V18 BSS Parameter Guide

8/10/2019 V18 BSS Parameter Guide

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V18.0 BSS Parameter User Guide (BPUG)

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PE/DCL/DD/000036 18.04 / EN Standard 16/01/2009 /545

PUBLICATION HISTORY

System release: GSM/BSS V18

January 2009

Issue 18.04/EN

Update for v18 Customer Readiness after review (iPOR Id 422749)

December 2008

Issue 18.03/EN

Update for v18 Channel Readiness

AMR Maximization parameters (§ 5.38), Single BCCH Multizone Enhancement (§ 5.20)

Enhanced Very Early Assignment (§ 5.46).

October 2008

Issue 18.02/EN

Update for v18 Customer Readiness after review (iPOR Id 391287)

AMR Maximization parameters (§ 5.38).

September 2008

Issue 18.01/EN

Update for v18 Customer Readiness

2G 3G UTRAN FDD TDD Cell Reselection (§ 4.4) Single BCCH Multizone Enhancement

(§4.8.2, §4.8.6, §4.10.6); AMR Based on Traffic (§4.22.8); AMR Maximization (§ 4.22.9);

Queuing HR (§ 4.22.10 ); Repeated Downlink FACCH (§ 4.22.11); Smart BTS Power

Management (§4.28 ); Enhanced Very Early Assignment (§ 4.29).




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May 2008

Issue 17.04/EN

Update for v17 Channel Readiness + 8 Weeks.

Update of 2G-3G Reselection description (§4.8.24);

March 2008

Issue 17.03/EN

Update for v17 Channel Readiness.

Update of Enhanced Measurement Reporting Parameters (§4.8.24); update of GSM to UMTShandovers parameters (§4.5.8); clarification on msTxPwrMax2ndBand on Power Control

Parameters section (§ 5.16)

October 2007

Issue 17.02/EN

Update for v17 Customer Readiness.

Update of GSM to UMTS handover with normal measurement reporting (§4.8.24); update of

legacy measurement reporting to include UTRAN neighbours (§4.5.8); update of reporting

priority criteria used in EMR (§4.6.5); summary of differences between MR and EMR (§4.6.8);

new section on eMLPP Preemption (§4.12); clarification of types of TDMA priorities (§6.19.2);new recommendation for trafficPCMAllocationPriority; new range for hoMarginBeg;

clarification of bscHopReconfUse; diversity mandatory for ICA (§4.18); list of Railway

parameters (§3.3); update of handover decision table for AMR TCH (§4.8.4); clarification of

Downlink DTX activation (§4.11.10).

July 2007

Issue 17.01/EN

Update for v17 Business Readiness + 21 weeks:

Legacy measurement report (§4.5); Enhanced Measurement Report (§4.6); Downlink FER

(§4.6.11); GSM to UMTS Handover (§4.8.24, §7.7); Single BCCH Multizone Enhancement

(§4.8.2, §4.8.6, §4.10.6); AMR-HR on preempted pDTCH (§4.22.6, impact on AboT §4.22.8);

A5/3 Encryption (§4.27); Smart BTS Power management (§4.28); Novel adaptive receiver

(§4.26); BSS CS Paging Coordination (§4.13.8); H3 impact on BTS cabinet power setting

(§4.16); new recommended values for modeModifyMandatory (§5.18); addition of RxQual

criteria for interzone handovers (§4.8.6); removal of reference to gsmProtocol in ICA (§5.30);

Sysinfo broadcast cycle (§4.17.3).




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March 2007

Issue 16.04/EN

Update for V16 ChR + 8 Weeks: Update of Network Synchronization (§ 4.34); Update of TX

Power Offset for signalling Channels parameters (§ 5.34); Update of network Synchronization

Impacts (§ 6.36); Addition of Network Synchronization Engineering planning (§ 6.37) and

Network Synchronization First Trial Results (§ 6.38)

November 2006

Issue 16.03/EN

Update for V16 ChR after review: Update of CellAllocation (§ 5.21); update PCM error

correction (§ 4.17.3); update of AMR based on traffic parameters (§ 5.34)

October 2006

Issue 16.02/EN

Update for V16 ChR: Update of TEPMOS for AMR and not EFR calls (§ 6.32.2 and § 6.32.6)

I Multipaging command message (§ 4.10.5); UI Multipaging command message (§ 4.10.6);

Tx Power Offset for signalling Channels (§ 4.23.9); update coderPoolConfiguration (§ 5.34);

update PCM error correction (§ 4.17.3); update rescue Handover (§ 4.6.1) and PBGT formula

(§ 4.5.1); PCM priority (§ 6.27.5); update Cabinet power description (§ 4.13.1)

May 2006

Issue 16.01/EN

Update for V16 CuR: 6.16 Frequency Spacing Between Two TRXs of the Same Area

March 2006

Issue 16.0/EN

Update for V16. CuR: Repeated Downlink FACCH (§ 4.23.8); Tx Power Offset for signalling

Channels (§ 4.23.9); Directed Retry Handover and queuing (§ 4.5.5, § 4.23.5 removed from

WPS description); updates on CellAllocation and mobileAllocation description (§ 5.21);updates

on AMR mechanism (§ 4.23.2, §4.23.4);updates on TCH allocation management (§ 4.9.1,

§4.9.2); updates on interference cancellation (§ 4.15, 6.22); update on lRxQualDLH and

lRxQualULH description (§ 5.10);update on dARPPh1Priority description (§ 5.36); update

coderPoolConfiguration (§ 5.34); update on extended cell description (§ 5.12)




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CONTENTS

1. ABOUT THIS DOCUMENT .........................................................................................................13

1.1. OBJECT..................................................................................................................................13 1.2. SCOPE ...................................................................................................................................13 1.3. AUDIENCE FOR THIS DOCUMENT ..............................................................................................13 1.4. DISCLAIMER ...........................................................................................................................13 1.5. DOCUMENT STRUCTURE ..........................................................................................................14 1.6. UPDATES TO PREVIOUS RECOMMENDATIONS ............................................................................15

1.6.1 between V17 and V18...................................................................................................15 1.6.2 between V16 and V17...................................................................................................15

2. RELATED DOCUMENTS............................................................................................................16

2.1. APPLICABLE DOCUMENTS ........................................................................................................16 2.2. REFERENCE DOCUMENTS .......................................................................................................16

3. CLASSIFICATION OF BSS PARAMETERS ..............................................................................19

3.1. P ARAMETER LIST ....................................................................................................................19 3.2. GSM UNUSED PARAMETERS....................................................................................................29 3.3. R AILWAY-SPECIFIC PARAMETERS (GSM-R)..............................................................................29 3.4. P ARAMETERS VERSUS BSS FEATURES AND PROCEDURES .......................................................30

3.4.1 2G Cell Selection and Reselection ...............................................................................30 3.4.2 2G-3G UTRAN FDD & TDD Cell Reselection..............................................................30 3.4.3 Legacy Measurement Reporting...................................................................................30 3.4.4 Enhanced Measurement Reporting ..............................................................................30 3.4.5 Level averaging.............................................................................................................30 3.4.6 Quality averaging ..........................................................................................................30 3.4.7 Distance averaging .......................................................................................................30 3.4.8 Cell eligibility..................................................................................................................30 3.4.9 Radio Link Failure .........................................................................................................31 3.4.10 Interference management.............................................................................................31 3.4.11 PCH and RACH control parameters .............................................................................31 3.4.12 Concentric Cell ..............................................................................................................31 3.4.13 Extended cell.................................................................................................................31

3.4.14 Queuing and priority management................................................................................31 3.4.15 eMLPP Preemption.......................................................................................................31 3.4.16 SMS-CB ........................................................................................................................31 3.4.17 Frequency Hopping.......................................................................................................32 3.4.18 Dynamic barring of access class ..................................................................................32 3.4.19 DTX ...............................................................................................................................32 3.4.20 Uplink Power control .....................................................................................................32 3.4.21 Downlink Power control.................................................................................................32 3.4.22 Directed retry handover.................................................................................................32 3.4.23 Uplink intracell handover...............................................................................................32 3.4.24 Downlink intracell handover..........................................................................................32 3.4.25 Intercell handover on bad uplink quality criterion..........................................................32 3.4.26 Intercell handover on bad downlink quality criterion .....................................................33

3.4.27 Intercell handover on bad uplink level criterion.............................................................33 3.4.28 Intercell handover on bad downlink level criterion ........................................................33 3.4.29 Intercell handover on power budget criterion................................................................33




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3.4.30 Microcellular algorithm ..................................................................................................33 3.4.31 Intercell handover on distance criterion ........................................................................33 3.4.32 Handover for traffic reasons..........................................................................................33 3.4.33 Handover decision according to adjacent cell...............................................................33 3.4.34 General protection against HO PingPong.....................................................................33

3.4.35 Call clearing...................................................................................................................33 3.4.36 Frequency Band favouring............................................................................................34 3.4.37 Minimum Time between Handover ...............................................................................34 3.4.38 Radio resource control at cell level ...............................................................................34 3.4.39 Pre-synchronised Handover..........................................................................................34 3.4.40 Interferer cancellation....................................................................................................34 3.4.41 Early HO decision .........................................................................................................34 3.4.42 Maximum RxLev for PBGT ...........................................................................................34 3.4.43 Cell Tiering ....................................................................................................................34 3.4.44 TTY support on BSC/TCU 3000....................................................................................34 3.4.45 Protection against intracell HO Ping-pong....................................................................34 3.4.46 Automatic Handover adaptation....................................................................................34 3.4.47 GSM to UMTS Handover ..............................................................................................35

3.4.48 Adaptative Full/Half Rate ..............................................................................................35 3.4.49 Wireless Priority Service ...............................................................................................35 3.4.50 Network Synchronization ..............................................................................................35 3.4.51 Repeated Downlink FACCH..........................................................................................35 3.4.52 Tx Power Offset for Signalling.......................................................................................35 3.4.53 Novel adaptive Receiver ...............................................................................................35 3.4.54 A5/3 Encryption Algorithm.............................................................................................36 3.4.55 BTS Smart Power Management ...................................................................................36 3.4.56 Enhanced Very Early Assignment ................................................................................36 3.4.57 AMR Maximization ........................................................................................................36

4. ALGORITHMS .............................................................................................................................37

4.1. INTRODUCTION .......................................................................................................................37 4.2. CONVENTIONS AND UNITS .......................................................................................................37

4.2.1 Unit ................................................................................................................................37 4.2.2 Phase 2 BTS and MS maximum transmitting output powers .......................................38 4.2.3 GSM Products sensitivity and power ............................................................................40 4.2.4 Conversion rules ...........................................................................................................41 4.2.5 Accuracy related to measurements ..............................................................................41 4.2.6 Frequency band ............................................................................................................42

4.3. 2G CELL SELECTION AND RESELECTION ..................................................................................43

4.3.1 Overview .......................................................................................................................43 4.3.2 Selection or reselection between cells of current Location Area..................................44

4.3.3 Reselection to a cell of a different Location Area..........................................................44 4.3.4 Additional reselection criterion (for phase 2).................................................................45

4.4. 2G - 3G UTRAN FDD & TDD CELL RESELECTION ..................................................................48

4.4.1 UE algorithm in GSM circuit mode................................................................................48 4.4.2 3G neighbouring cell information in SI2quater..............................................................51 4.4.3 Control Information in SI2Quater ..................................................................................52

4.5. LEGACY MEASUREMENT REPORTING .......................................................................................53

4.5.1 Principle.........................................................................................................................53 4.5.2 Neighbour cell Monitoring .............................................................................................53 4.5.3 Serving cell monitoring..................................................................................................54 4.5.4 Reporting Period ...........................................................................................................54

4.5.5 Neighbour Cell Lists......................................................................................................54 4.5.6 Measurement Report Content.......................................................................................55 4.5.7 Multiband reporting .......................................................................................................56




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4.5.8 UTRAN cell reporting using legacy measurement reports (V17)..................................56 4.5.9 Note on powerControlIndicator parameter....................................................................59 4.5.10 Note on Rxlev Uplink/Downlink difference....................................................................60

4.6. ENHANCED MEASUREMENT REPORTING (EMR) .......................................................................61

4.6.1 Principle.........................................................................................................................61 4.6.2 Reporting period............................................................................................................61 4.6.3 Enhanced Measurement Report content ......................................................................61 4.6.4 Neighbour Cell lists .......................................................................................................62 4.6.5 Order of reporting priority of neighbour cells.................................................................63 4.6.6 Measurement Information message .............................................................................63 4.6.7 MI/SACCH scheduling ..................................................................................................66 4.6.8 Main differences between Normal and Enhanced Measurement Reporting ................66 4.6.9 New BSS parameters....................................................................................................67 4.6.10 Impact of EMR on Interference Matrix ..........................................................................68 4.6.11 Impact of EMR on Radio Measurement Distribution (RMD).........................................69

4.7. UPLINK MEASUREMENT PROCESSING ......................................................................................70

4.7.1 Principle.........................................................................................................................70 4.7.2 Averaging process ........................................................................................................71 4.7.3 Rescaling.......................................................................................................................72 4.7.4 Missing downlink measurements..................................................................................72

4.8. DIRECT TCH ALLOCATION AND H ANDOVER ALGORITHMS .........................................................75

4.8.1 General formulas...........................................................................................................75 4.8.2 Direct TCH Allocation....................................................................................................78 4.8.3 Handovers.....................................................................................................................82 4.8.4 Handovers decision priority...........................................................................................85 4.8.5 Directed Retry Handover...............................................................................................87 4.8.6 Concentric/DualCoupling/DualBand Cell Handover .....................................................90 4.8.7 Rescue Handover .........................................................................................................96 4.8.8 Power Budget Handover...............................................................................................98 4.8.9 Handover for traffic reasons..........................................................................................98 4.8.10 Handover decision according to adjacent cell priorities and load.............................. 101 4.8.11 Automatic cell tiering.................................................................................................. 102 4.8.12 Microcellular Handover .............................................................................................. 107 4.8.13 Forced Handover ....................................................................................................... 110 4.8.14 Early HandOver Decision........................................................................................... 111 4.8.15 Maximum RxLev for Power Budget ........................................................................... 112 4.8.16 Pre-synchronized HO................................................................................................. 113 4.8.17 Radio channel allocation............................................................................................ 113 4.8.18 Define eligible neighbor cells for intercell handover (except directed retry) .............. 114 4.8.19 Handover to 2nd best candidate when return to old channel .................................... 115 4.8.20 Protection against RunHandover=1........................................................................... 115 4.8.21 General protection against HO ping-pong ................................................................. 116 4.8.22 Automatic handover adaptation ................................................................................. 118 4.8.23 Protection against Intracell HO Ping-Pong ................................................................ 121 4.8.24 GSM to UMTS handover............................................................................................ 124

4.9. H ANDOVER ALGORITHMS ON THE MOBILE SIDE ..................................................................... 135 4.10. POWER CONTROL ALGORITHMS ........................................................................................... 136

4.10.1 Step by step Power Control ....................................................................................... 136 4.10.2 One shot Power Control............................................................................................. 137 4.10.3 Fast Power Control at TCH assignment .................................................................... 139 4.10.4 Power Control on mobile side .................................................................................... 140 4.10.5 AMR Power Control ................................................................................................... 140 4.10.6 Power Adaptation After An Interzone HO .................................................................. 141

4.11. TCH ALLOCATION M ANAGEMENT ......................................................................................... 144




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4.11.1 TCH Allocation and Priority........................................................................................ 144 4.11.2 Queuing...................................................................................................................... 148 4.11.3 Barring of access class .............................................................................................. 152 4.11.4 Radio link failure process (run by the MS)................................................................. 157 4.11.5 Radio link failure process (run by the BTS) ............................................................... 157

4.11.6 Call reestablishment procedure ................................................................................. 158 4.11.7 Call Clearing Process (run by BTS) ........................................................................... 159 4.11.8 Interference Management (BTS and BSC) ................................................................ 159 4.11.9 Uplink DTX................................................................................................................. 159 4.11.10 Downlink DTX......................................................................................................... 161

4.12. EMLPP PREEMPTION .......................................................................................................... 163

4.12.1 Principle of eMLPP..................................................................................................... 163 4.12.2 End-to-end perspective.............................................................................................. 164 4.12.3 Preemption attributes................................................................................................. 166 4.12.4 BSS Radio Resource preemption algorithm.............................................................. 167 4.12.5 Activation parameter .................................................................................................. 170 4.12.6 eMLPP preemption versus PDTCH preemption ........................................................ 170

4.12.7 Interworking................................................................................................................171 4.12.8 Restrictions.................................................................................................................172

4.13. PCH AND RACH CHANNEL CONTROL ................................................................................... 173

4.13.1 Paging command Process ......................................................................................... 173 4.13.2 Paging command repetition process (run by BTS) .................................................... 175 4.13.3 Request access command process........................................................................... 177 4.13.4 Request access command repetition process ........................................................... 177 4.13.5 I Multipaging command message .............................................................................. 178 4.13.6 UI Multipaging command message............................................................................ 180 4.13.7 Network Mode of Operation I support in BSS............................................................ 182 4.13.8 BSS CS Paging Coordination .................................................................................... 184

4.14. FREQUENCY HOPPING ......................................................................................................... 186 4.14.1 Frequency hopping principles .................................................................................... 186 4.14.2 Main benefits of frequency hopping........................................................................... 187 4.14.3 Synthesised frequency hopping................................................................................. 189 4.14.4 Baseband frequency Hopping.................................................................................... 190 4.14.5 Ad-Hoc frequency plan............................................................................................... 192

4.15. BSC OVERLOAD M ANAGEMENT MECHANISMS....................................................................... 193

4.15.1 BSC3000 Overload Management .............................................................................. 193 4.15.2 Load Balancing .......................................................................................................... 195 4.15.3 Evolution of Load Balancing....................................................................................... 195

4.16. C ABINET OUTPUT POWER SETTING ...................................................................................... 197

4.16.1 Cabinet power description.......................................................................................... 197 4.16.2 Pr computation........................................................................................................... 198 4.16.3 Ps computation .......................................................................................................... 198

4.17. SYSTEM INFORMATION MESSAGES RELATED FEATURES ........................................................ 200

4.17.1 Dual Band Handling ................................................................................................... 200 4.17.2 SI2Quater & SI13 on Extended or Normal BCCH...................................................... 203 4.17.3 Summary of SYSINFO Scheduling............................................................................ 205

4.18. INTERFERENCE C ANCELLATION ............................................................................................ 206 4.19. EXTENDED CCCH ............................................................................................................... 208

4.19.1 Customer/service provider benefits ........................................................................... 208

4.19.2 Feature functional description.................................................................................... 208 4.20. CELLULAR TELEPHONE TEXT MODEM (TTY) ......................................................................... 209




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5.1. INTRODUCTION .................................................................................................................... 283 5.2. 2G CELL SELECTION AND RESELECTION P ARAMETERS.......................................................... 284 5.3. 2G-3G CELL RESELECTION PARAMETERS............................................................................. 289 5.4. LEGACY MEASUREMENT REPORTING P ARAMETERS ............................................................... 292 5.5. ENHANCED MEASUREMENT REPORTING P ARAMETERS .......................................................... 293

5.6. R ADIO LINK F AILURE P ARAMETERS....................................................................................... 297 5.7. SIGNAL QUALITY AVERAGING P ARAMETERS .......................................................................... 300 5.8. SIGNAL STRENGTH AVERAGING P ARAMETERS....................................................................... 302 5.9. NEIGHBOR CELL AVERAGING P ARAMETERS .......................................................................... 305 5.10. DISTANCE AVERAGING P ARAMETERS .................................................................................... 307 5.11. H ANDOVER (GLOBAL) P ARAMETERS ..................................................................................... 309 5.12. INTRACELL H ANDOVER P ARAMETERS.................................................................................... 322 5.13. INTERCELL H ANDOVER THRESHOLD P ARAMETERS ................................................................ 325 5.14. H ANDOVER FOR MICROCELLULAR NETWORK P ARAMETERS ................................................... 328 5.15. DISTANCE M ANAGEMENT P ARAMETERS ................................................................................ 330 5.16. POWER CONTROL P ARAMETERS........................................................................................... 334 5.17. TCH ALLOCATION M ANAGEMENT P ARAMETERS .................................................................... 342 5.18. EMLPP R ADIO RESOURCE PREEMPTION PARAMETER ........................................................... 356

5.19. DIRECTED RETRY H ANDOVER P ARAMETERS ......................................................................... 357 5.20. CONCENTRIC CELL P ARAMETERS ......................................................................................... 361 5.21. INTERFERENCE LEVEL P ARAMETERS .................................................................................... 371 5.22. R ADIO RESSOURCES CONTROL AT CELL LEVEL .................................................................... 374 5.23. BSS TIMERS ....................................................................................................................... 375 5.24. P AGING P ARAMETERS.......................................................................................................... 382 5.25. FREQUENCY HOPPING P ARAMETERS .................................................................................... 387 5.26. BSC LOAD M ANAGEMENT P ARAMETERS............................................................................... 394 5.27. DUALB AND CELL P ARAMETERS ............................................................................................ 395 5.28. DTX P ARAMETERS .............................................................................................................. 402 5.29. MISCELLANEOUS ................................................................................................................. 403 5.30. INTERFERENCE C ANCELLATION P ARAMETERS ....................................................................... 406 5.31. PCM ERROR CORRECTION P ARAMETERS ............................................................................. 408

5.32. CELL TIERING P ARAMETERS................................................................................................. 409 5.33. ENCODING P ARAMETERS ..................................................................................................... 412 5.34. SMS-CELL BROADCAST P ARAMETERS ................................................................................. 413 5.35. PROTECTION AGAINST INTRACELL HO PING-PONG P ARAMETERS .......................................... 414 5.36. AUTOMATIC H ANDOVER ADAPTATION P ARAMETERS .............................................................. 415 5.37. GSM TO UMTS HANDOVER PARAMETERS............................................................................. 417 5.38. AMR - ADAPTATIVE MULTI R ATE FR/HR P ARAMETERS ......................................................... 425 5.39. WPS - WIRELESS PRIORITY SERVICES P ARAMETERS ............................................................ 444 5.40. NETWORK SYNCHRONIZATION PARAMETERS ......................................................................... 445 5.41. NETWORK MODE OF OPERATION P ARAMETERS ..................................................................... 447 5.42. BSS CS P AGING COORDINATION PARAMETER ...................................................................... 448 5.43. NOVEL ADAPTIVE RECEIVER PARAMETER .............................................................................. 448 5.44. A5/3 ENCRYPTION ALGORITHM PARAMETERS........................................................................ 449 5.45. BTS SMART POWER M ANAGEMENT P ARAMETERS................................................................. 451 5.46. ENHANCED VERY E ARLY ASSIGNMENT P ARAMETERS ............................................................ 453

6. ENGINEERING ISSUES........................................................................................................... 454

6.1. GSM/GPRS TS SHARING: PRIORITY H ANDLING AND QUEUING ............................................. 454

6.1.1 Resources reserved for priority 0 and preemption..................................................... 454 6.1.2 GSM/GPRS TS sharing and queuing: ....................................................................... 455 6.1.3 Resources strategy .................................................................................................... 456

6.2. MINIMUM TIME BETWEEN H ANDOVER.................................................................................... 457

6.2.1 Micro-cellular network ................................................................................................ 457 6.2.2 Non micro-cellular network......................................................................................... 459

6.3. DIRECTED RETRY H ANDOVER BENEFIT ................................................................................. 460




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6.3.1 Benefit of feature on mono-layer structure................................................................. 460 6.3.2 Benefit of feature on multi-layers structure ................................................................ 461

6.4. CONCENTRIC CELLS ............................................................................................................ 464

6.4.1 Concentric Cell Parameter Definition......................................................................... 465

6.4.2 Concentric Cell Field Experience............................................................................... 468 6.5. IMPACT OF DTX ON AVERAGING ........................................................................................... 472 6.6. BEST NEIGHBOUR CELLS STABILITY ..................................................................................... 473 6.7. TCH ALLOCATION GENERAL RULES ..................................................................................... 474 6.8. GENERAL R ADIO FREQUENCY RULES ................................................................................... 475 6.9. DIFFERENCE BETWEEN UPLINK AND DOWNLINK LEVELS ........................................................ 476 6.10. EFFECTS OF SMS-CELL BROADCAST USE ON “NOOFBLOCKSFOR ACCESSGRANT”................. 477 6.11. IMPACT OF THE AVERAGING ON THE H ANDOVERS .................................................................. 478

6.11.1 Global statistics.......................................................................................................... 478 6.11.2 Study of reactivity....................................................................................................... 479 6.11.3 Ping pong vs Reactivity.............................................................................................. 479

6.12. IMPACT OF C ALL RE-ESTABLISHMENT ON THE NETWORK ....................................................... 480 6.12.1 Impact on capacity ..................................................................................................... 480 6.12.2 Impact on call drops................................................................................................... 480

6.13. MINIMUM COUPLING LOSS (MCL)......................................................................................... 481

6.13.1 Broadband noise ........................................................................................................ 481 6.13.2 Blocking...................................................................................................................... 481 6.13.3 How to improve the MCL............................................................................................ 482

6.14. MICROCELL BENEFITS.......................................................................................................... 483

6.14.1 Frequency super reuse .............................................................................................. 483 6.14.2 Traffic Homogenization .............................................................................................. 483 6.14.3 Radio conditions improvement................................................................................... 483 6.14.4 Microcell Field Experience ......................................................................................... 484

6.15. INTERFERENCE C ANCELLATION USAGE ................................................................................. 485 6.16. STREET CORNER ENVIRONMENT .......................................................................................... 486

6.16.1 Description ................................................................................................................. 486 6.16.2 Case A: Mobile moving straight ................................................................................. 487 6.16.3 Case B: Mobile turning at the cross road................................................................... 488

6.17. SYNCHRONIZED HO VERSUS NOT SYNCHRONIZED HO.......................................................... 489

6.17.1 Introduction.................................................................................................................489 6.17.2 OMC-R Parameter settings........................................................................................ 489 6.17.3 Timing HO.................................................................................................................. 490

6.18. BTS SENSITIVITY................................................................................................................. 494 6.18.1 Definition of sensitivity................................................................................................ 494 6.18.2 Static and dynamic sensitivity .................................................................................... 495 6.18.3 Typical / guaranteed sensitivity.................................................................................. 495 6.18.4 Space diversity gains ................................................................................................. 495 6.18.5 Cross-polarization antenna use ................................................................................. 496 6.18.6 Circular polarization and crosspolar antennas........................................................... 497

6.19. SDCCH DIMENSIONING AND TDMA PRIORITIES.................................................................... 499

6.19.1 SDCCH Dimensioning................................................................................................ 499 6.19.2 TDMA priorities .......................................................................................................... 501

6.20. ENGINEERING GUIDELINES FOR EXCEPTIONAL EVENTS.......................................................... 503

6.20.1 BSS prerequisite ........................................................................................................ 503 6.20.2 BSS: Suggestions for parameters to be modified for the special event .................... 504




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6.20.3 NSS level.................................................................................................................... 505

6.21. IMPACT OF AUTOMATIC H ANDOVER ADAPTATION ACTIVATION................................................. 508

6.21.1 Related parameters.................................................................................................... 508 6.21.2 Deployment Optimization and Monitoring.................................................................. 509

6.22. H ANDOVER FOR TRAFFIC REASONS ACTIVATION GUIDELINE .................................................. 513

6.22.1 Algorithms and Parameters Definition ....................................................................... 513 6.22.2 Expected effects and recommended parameters ...................................................... 515

6.23. DISABLING AMR BASED ON TRAFFIC IN V15.1.1.................................................................... 519

7. APPENDIX A: MAIN EXCHANGE PROCEDURES AT BSC LEVEL...................................... 520

7.1. ESTABLISHMENT PROCEDURE .............................................................................................. 520 7.2. CHANNEL MODE PROCEDURE .............................................................................................. 521 7.3. DEDICATED CHANNEL ASSIGNMENT ...................................................................................... 522 7.4. INTRACELL H ANDOVER PROCEDURE ..................................................................................... 523 7.5. INTRABSS H ANDOVER PROCEDURE ..................................................................................... 524 7.6. INTERBSS H ANDOVER PROCEDURE ..................................................................................... 525 7.7. 2G-3G H ANDOVER PROCEDURE........................................................................................... 526 7.8. RESOURCE RELEASE PROCEDURE (EXAMPLE)...................................................................... 527 7.9. SACCH DEACTIVATION PROCEDURE ................................................................................... 528 7.10. MOBILE TERMINATING C ALL ................................................................................................. 529 7.11. MOBILE ORIGINATING C ALL .................................................................................................. 530

8. APPENDIX B: ERLANG TABLE.............................................................................................. 531

9. ABBREVIATIONS & DEFINITIONS......................................................................................... 534

9.1. ABBREVIATIONS ................................................................................................................... 534 9.2. DEFINITIONS........................................................................................................................ 540

10. INDEX ....................................................................................................................................... 543




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1. ABOUT THIS DOCUMENT

1.1. OBJECT

This document describes BSS GSM and Nortel algorithms and parameters from an

engineering point of view.

This document is written by Nortel BSS experts and contains extensive Nortel BSS

parameters setting know-how. Informations coming from experiments, studies, simulations are

also related in the document.

The parameters are called by the name used in the features and algorithms. For their

corresponding name (when different) at the OMC, refer to [R6].

The parameters described in this document are the ones used in the features and algorithms.

Refer to [R2] to have a description of all BSS parameters.

1.2. SCOPE

This version is issued for the ChR milestone of the V18 BSS GSM release.

1.3. AUDIENCE FOR THIS DOCUMENT

Draft and preliminary: Nortel R&D, PLM and Eng'

Standard: customers and Nortel R&D, Product Line Management and Engineering teams.'

1.4. DISCLAIMER

Depending on particular objective, call profile and network characteristics, a parameter setting

can never be judged as being universally optimized.

The recommended setting presented in this document should result in good network

performance; however several iterations and improvements may be required in order to be

optimal according to customer specificities. Every effort is made to incorporate suggestions

and feedback received from customers.

PRELIMINARY VERSION

The recommended setting has been validated with product and system tests in lab. This

document will be updated and adjusted after the first results from VO site or new Product

Test/End-to-end labs if available.

STANDARD VERSION

This is a living document and the contents will be modified based on feedback received from

R&D, Engineering and customers.




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1.5. DOCUMENT STRUCTURE

In chapter §3 CLASSIFICATION OF BSS PARAMETERS, BSS algorithm parameters are

presented in alphabetic order according to their group. Process and related objects are also

provided.

Chapter §4 ALGORITHMS describes the GSM Nortel BSS algorithms and recommends ways

to use them efficiently.

BSS parameters used in the algorithms are described in chapter §5 ALGORITHM

PARAMETERS. For each parameter, a recommended value and a default value are given.

Engineering rules explain how to select the parameter value.

In chapter §6 ENGINEERING ISSUE, engineering issues resulting from studies on parameter

setting and on products, simulations and experiments are developped.

Chapter §7 APPENDIX A: MAIN EXCHANGE PROCEDURES AT BSC LEVEL gives the main

exchange procedures at BSC level.

In chapter §8 APPENDIX B: ERLANG TABLE, an Erlang table presents the maximum offered

load according to the number of channels and the blocking rate.

In chapter §9 ABBREVIATIONS & DEFINITIONS, the signification of all the abbrevations used

in this document and some key-definitions are explained.




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1.6. UPDATES TO PREVIOUS RECOMMENDATIONS

1.6.1 BETWEEN V17 AND V18

No modification

1.6.2 BETWEEN V16 AND V17

modeModifyMandatory:

New recommended value set to “not used”. This parameter is no longer useful but setting to

“used” may yield undesirable side-effects in particular circumstances.

enhancedTRAUframeIndication :

This parameter is no longer useful in V17 due to the end of support of the PCM Error

Correction feature.

pcmErrorCorrection :

This parameter is no longer useful in V17 duie to the end of support of the PCM Error

Correction feature.

bscHopReconfUse :

New recommended value for BSC that manage only BTS with hybrid coupling.

Old recommendation : “false (mandatory for hybrid coupling).”

New recommendation : “the value (true or false) is indifferent for a BSC that manages only

BTS with hybrid coupling”.

trafficPCMAllocationPriority :

New recommended value for BCCH TDMA.

Old recommendation : highest priority (0) for BCCH TDMA.

New recommendation : lowest priority (255) for BCCH TDMA.




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3. CLASSIFICATION OF BSS PARAMETERS

3.1. PARAMETER LIST

The following table gives a classification of the main BSS tunable parameters sorted by

alphabetical order, the object they are associated to at the OMC-R (as they are described in

[R1]) and the main features using those parameters.

Parameter name BSS Object- Feature(s) using this parameter

accessClassCongestion V9 bts Barring of access class

adaptiveReceiver V17 transceiver Novel Adaptive Receiver

adjacent_cell_umbrella_ref V9 bts Directed Retry Handover

allocPriorityTable V7 bts TCH Allocation and Priority

Queuing

WPS – Queuing management

allocPriorityThreshold V7 bts TCH Allocation and Priority

Queuing

allocPriorityTimers V7 bts Queuing


allocWaitThreshold V7 bts Queuing


allOtherCasesPriority V7 bts TCH Allocation and Priority

Queuing

amrUlFrAdaptationSet V15 bts AMR Codec mode adaptation

amrUlHrAdaptationSet V15 bts AMR Codec mode adaptation

amrDlFrAdaptationSet V15 bts AMR Codec mode adaptation

amrUlHrAdaptationSet V15 bts AMR Codec mode adaptation

amrDirectAllocIntRxLevDL V14 bts AMR Handover mechanisms

Direct TCH Allocation

amrDirectAllocIntRxLevUL V14 bts AMR Handover mechanisms


amrDirectAllocRxLevDL V14 bts AMR Handover mechanisms


amrDirectAllocRxLevUL V14 bts AMR Handover mechanisms


amrFRIntercellCodecMThresh V14 handOverControl AMR Handover mechanisms

amrFRIntracellCodecMThresh V14 handOverControl AMR Handover mechanisms

amrHRIntercellCodecMThresh V14 handOverControl AMR Handover mechanisms

amrHRtoFRIntracellCodecMThresh V14 handOverControl AMR Handover mechanisms

amriRxLevDLH V14 handOverControl AMR Handover mechanisms

amriRxLevULH V14 handOverControl AMR Handover mechanisms

amrReserved1 V16 handOverControl AMR RATSCCH Proceudre

amrReserved2 V14 handOverControl AMR Legacy L1M

answerPagingPriority V7 bts TCH Allocation and Priority

Queuing




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assignRequestPriority V7 bts TCH Allocation and Priority

Queuing

averagingPeriod V7 handOverControl Radio channel allocation

Interference Management

baseColourCode V7 bts Network Synchronization

bCCHFrequency V7 adjacentCellHandover

bCCHFrequency V7 adjacentCellReselection

bCCHFrequency V7 bts

biZonePowerOffset V12 adjacentCellHandover General formulas


Concentric/DualCoupling/DualBand CellHandover

biZonePowerOffset V12 handoverControl General formulas


Concentric/DualCoupling/DualBand Cell

Handover

bscHopReconfUse V8 bsc Reconfiguration procedure

bscMSAccessClassBarringFunction V9 bsc Barring of access class

bscQueuingOption V7 signallingPoint Queuing


bsMsmtProcessingMode V7 bts Measurement Processing

bsPowerControl V7 powerControl Power Control Algorithms

AMR Power Control

bssMapT1 V7 bsc

bssMapT12 V7 bsc

bssMapT13 V7 bsc

bssMapT19 V8 bsc

bssMapT20 V8 bsc

bssMapT4 V7 bsc

bssMapT7 V7 bsc

bssMapT8 V7 bsc

bssMapTchoke V7 bsc

bssPagingCoordination V17 bts BSS CS Paging Coordination

bssSccpConnEst V7 signallingPoint

bsTxPwrMax V7 powerControl General formulas

Cabinet Output Power Setting

btsSMSynchroMode V15 btsSiteManager Network Synchronization

bts Time Between HO configuration V9

V12

bts Minimum time between Handover

General protection against HO ping-pong

btsHopReconfRestart V8 bts Reconfiguration procedure

btsIsHopping V7 bts Frequency Hopping

btsMSAccessClassBarringFunction V9 bts Barring of access class

btsThresholdHopReconf V8 bts Reconfiguration procedure

callClearing V7 bts Call Clearing Process

callReestablishment V7 bts Radio link failure process,

Call reestablishment procedure

callReestablishmentPriority V7 bts TCH Allocation and Priority

Queuing

capacityTimeRejection V14 handOverControl Protection against Intracell HO Ping-Pong

AMR Handover mechanisms




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cellAllocation V7 bts Frequency Hopping

cellBarQualify V8 bts Selection, Reselection Algorithms

cellBarred V7 bts Selection, Reselection Algorithms

cellDeletionCount V7 bts Measurement Processing

Handovers screening

cellDtxDownLink V7 bts DTX

cellReselectHysteresis V8 bts Selection, Reselection Algorithms

cellReselectOffset V7 bts Selection, Reselection Algorithms

cellReselInd V8 bts Selection, Reselection Algorithms

cellType V7 adjacentCellHandOver Microcellular Algo

cellType V7 bts Microcellular Algo

channelType V7 channel

cId V17 adjacentCellUTRAN GSM to UMTS handover

coderPoolConfiguration V14 transcoder AMR Channel allocation

Cellular Telephone Text Modem (TTY)

compressedModeUTRAN V17 bts GSM to UMTS handover

concentAlgoExtMsRange V9 handOverControl Direct TCH Allocation


concentAlgoExtRxLev V9 handOverControl Direct TCH Allocation


concentAlgoExtRxLevUL V18 handOverControl Direct TCH Allocation

Concentric/DualCoupling/DualBand Cell

Handover

concentAlgoIntMsRange V9 handOverControl Concentric/DualCoupling/DualBand CellHandover

concentAlgoIntRxLev V9 handOverControl Concentric/DualCoupling/DualBand CellHandover

concentAlgoIntRxLevUL V18 handOverControl Direct TCH Allocation


concentric_cell V9

V12

bts Concentric/DualCoupling/DualBand CellHandover

cpueNumber V12 btsSiteManager Cell Group Management

CPU/BIFP LOAD SHARING

cypherModeReject V8 signallingPoint A5/3 Encryption algorithm

dARPPh1Priority V15 transceiver Network Synchronization

Data14_4OnNoHoppingTs V12 bts PCM Error Correction

data mode 14.4 kbit/s V11 transcoder board PCM Error Correction

data non transparent mode V11 bts PCM Error Correction

data non transparent mode V11 signallingPoint PCM Error Correction

data transparent mode V11 bts PCM Error Correction

data transparent mode V11 signallingPoint PCM Error Correction

delayBetweenRetrans V8 bts Paging command repetition process

directAllocIntFrRxLevDL V18 handOverControl Direct TCH Allocation

directAllocIntFrRxLevUL V18 handOverControl Direct TCH Allocation

directedRetry V9 adjacentCellHandOver Directed Retry Handover

directedRetryModeUsed V9 bts Directed Retry Handover




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directedRetryPrio V12 bts Directed Retry Handover

distHreqt V7 handOverControl Measurement Processing

distWtsList V7 handOverControl Measurement Processing

diversity V7 bts Interference Cancellation

diversityUTRAN V17 adjacentCellUTRAN GSM to UMTS handover

dtxMode V7

V14

bts DTX

EATrafficLoadEnd V18 bts Enhanced Very Early Assignment

EATrafficLoadStart V18 bts Enhanced Very Early Assignment

early classmark sending V10 bts Modified SYS INFO 3

Location Services

earlyClassmarkSendingUTRAN V17 bts GSM to UMTS handover

emergencyCallPriority V7 bts TCH Allocation and Priority

Queuing

enableRepeatedFacchFr V16 bts Repeated Downlink FACCH

enableRepeatedFacchHr V18 bts Repeated Downlink FACCH

encrypAlgoAssComp V8 signallingPoint A5/3 Encryption algorithm

encrypAlgoCiphModComp V8 signallingPoint A5/3 Encryption algorithm

encrypAlgoHoPerf V8 signallingPoint A5/3 Encryption algorithm

encrypAlgoHoReq V8 signallingPoint A5/3 Encryption algorithm

encryptionAlgorSupported V7 bsc A5/3 Encryption algorithm

enhancedTRAUFrameIndication V12 bsc PCM Error Correction

enhCellTieringConfiguration V14 handOverControl Cell Tiering Parameters

estimatedSiteLoad V15 btsSiteManager V15.1 Evolution of Load Balancing

extended cell V9 bts

facchPowerOffset V16 bts Tx Power Offset for Signalling

fDDARFCN V17 adjacentCellUTRAN GSM to UMTS handover

fDDMultiratReporting V17 bts Enhanced Measurement Reporting

GSM to UMTS handover

UTRAN cell reporting using legacymeasurement reports (V17)

fDDreportingThreshold V17 handOverControl Enhanced Measurement Reporting


fDDreportingThreshold2 V17 handOverControl Enhanced Measurement Reporting



fhsRef V7 channel Frequency Hopping filteredTrafficCoefficient V15 bts AMR based on traffic

fnOffset V15 btsSiteManager Network Synchronization

forced handover algo V9 adjacentCellHandOver Forced Handover

fullHRCellLoadEnd V18 bts AMR Maximization

fullHRCellLoadStart V18 Bts AMR Maximization

frAMRPriority V14 transceiver AMR Channel allocation

frPowerControlTargetMode V14 transceiver AMR Power Control

frPowerControlTargetModeDl V16 powerControl AMR Power Control

gprsNetworkModeOperation V15 bts Network Mode of Operation I support in BSS

gprsPreemptionForHR V17 bsc pDTCH Preemption by AMR HR calls

gsmToUmtsReselection V14 bts 2G - 3G Cell Reselection

gsmToUMTSServiceHo V17 bsc GSM to UMTS handover




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handOver from signalling channel V7 handOverControl Direct TCH Allocation and Handover Algorithms

hoMargin V7 adjacentCellHandOver Handovers

Power budget formula

Handover for traffic reasons

Define eligible neighbor cells for intercellhandover

Automatic handover adaptation

hoMarginAMR V14 adjacentCellHandOver AMR Handover mechanisms

Handovers

hoMarginAMRUTRAN V17 adjacentCellUTRAN GSM to UMTS handover

hoMarginBeg V11 bts Handovers

Early HandOver Decision



hoMarginDist V8 adjacentCellHandOver Handover condition for leaving a cell ondistance


hoMarginDistUTRAN V17 adjacentCellUTRAN GSM to UMTS handover

hoMarginRxLev V8 adjacentCellHandOver Handovers


hoMarginRxLevUTRAN V17 adjacentCellUTRAN GSM to UMTS handover

hoMarginRxQual V8 adjacentCellHandOver Handovers

Define eligible neighbor cells for intercell

handover hoMarginRxQualUTRAN V17 adjacentCellUTRAN GSM to UMTS handover

hoMarginTiering V14 handOverControl Automatic cell tiering

hoMarginTrafficOffset V12 adjacentCellHandOver Handover for traffic reasons

hoMarginTrafficOffsetUTRAN V17 adjacentCellUTRAN GSM to UMTS handover

hoMarginUTRAN V17 adjacentCellUTRAN GSM to UMTS handover

hoPingpongCombination V12

V14

adjacentCellHandOver General protection against HO ping-pong

hoPingpongCombinationUTRAN V17 adjacentCellUTRAN GSM to UMTS handover

hoPingpongTimeRejection V12 adjacentCellHandOver General protection against HO ping-pong

hoPingpongTimeRejectionUTRAN V17 adjacentCellUTRAN GSM to UMTS handover

hoppingSequenceNumber V7 frequencyHopSystem Synthesised frequency hopping

hoRejectionTimeOverloadUTRAN V17 adjacentCellUTRAN GSM to UMTS handover

hoSecondBestCellConfiguration V9 bsc Handover to 2nd best candidate when returnto old channel

hoTraffic V12 bsc Handover for traffic reasons

hoTraffic V12 bts Handover for traffic reasons

hrAMRPriority V14 transceiver AMR Channel allocation

hrCellLoadEnd V14 bts AMR Channel allocation

hrCellLoadStart V14 bts AMR Channel allocation

hrPowerControlTargetMode V14 powerControl AMR Power Control

hrPowerControlTargetModeDl V16 powerControl AMR Power Control

incomingHandOver V7 handOverControl Handovers

interBscDirectedRetry V9 bsc Directed Retry Handover




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interBscDirectedRetryFromCell V9 bts Directed Retry Handover

interCellHOExtPriority V7 bts TCH Allocation and Priority

Queuing

interCellHOIntPriority V7 bts TCH Allocation and Priority Queuing

interferenceType V12 adjacentCellHandover Automatic cell tiering

interferer cancel algo usage V10 bts Interference Cancellation

intraBscDirectedRetry V9 bsc Directed Retry Handover

intraBscDirectedRetryFromCell V9 bts Directed Retry Handover

intraCell V7

V12

handOverControl Intracell Handover decision for signal quality

intraCellHOIntPriority V7 bts TCH Allocation and Priority

Queuing

intraCellQueuing V8 bts Queuing

intraCellSDCCH V8 handOverControl Intracell Handover decision for signal quality

layer3MsgCyphModComp V8 signallingPoint A5/3 Encryption algorithm

locationAreaCodeUTRAN V17 adjacentCellUTRAN GSM to UMTS handover

lRxLevDLH V7 handOverControl Handover condition for leaving a cell on rxlev


lRxLevDLP V7 powerControl Power Control Algorithms

AMR Power Control

lRxLevULH V7 handOverControl Handover condition for leaving a cell on rxlev

lRxLevULP V7 powerControl Power Control Algorithms

AMR Power Control

lRxQualDLH V7 handOverControl Handover condition for leaving a cell on rxqual lRxQualDLP V7 powerControl Power Control Algorithms

AMR Power Control

lRxQualULH V7 handOverControl Handover condition for leaving a cell on rxqual

lRxQualULP V7 powerControl Power Control Algorithms

AMR Power Control

maio V7 channel Synthesised frequency hopping

masterBtsSmId V15 btsSiteManager Network Synchronization

maxNumberRetransmission V8 bts Request access command repetition process

measurementProcAlgorithm V12 bts Measurement Processing

Direct TCH Allocation and Handover Algorithms

microCellCaptureTimer V8 adjacentCellHandOver Microcellular Algo

microCellStability V8 adjacentCellHandOver Microcellular Algo

minNbOfTDMA V7 bts

missDistWt V7 handOverControl Measurement Processing

missRxLevWt V7 handOverControl Measurement Processing

missRxQualWt V7 handOverControl Measurement Processing

mobileCountryCodeUTRAN V17 adjacentCellUTRAN GSM to UMTS handover

mobileNetworkCodeUTRAN V17 adjacentCellUTRAN GSM to UMTS handover

mobileAllocation V7 frequencyHopSystem Synthesised frequency hopping

Baseband Frequency Hopping

modeModifyMandatory V9 bsc Directed Retry Handover

msBtsDistanceInterCell V7 handOverControl Handovers screening




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Handover condition for leaving a cell ondistance

msRangeMax V7 handOverControl Handover condition for leaving a cell ondistance

msTxPwrMax V7 bts Accuracy related to measurements

General formulas

Forced Handover

Power Control Algorithms

msTxPwrMax2ndBand V12 bts Concentric/DualCoupling/DualBand CellHandove

msTxPwrMaxCCH V7 bts Selection, Reselection Algorithms

msTxPwrMaxCell V7 adjacentCellHandOver General formulas

Handovers screening

Directed Retry Handover: BTS

Forced Handover


Power Control Algorithms

multi band reporting V10 bts Multiband reporting

Enhanced Measurement Reporting


nbLargeReuseDataChannels V14 bts Automatic cell tiering

nbOfRepeat V8 bts Paging command repetition process

nCapacityFRRequestedCodec V14 handOverControl AMR Handover mechanisms

neighDisfavorOffset V14 handOverControl Automatic handover adaptation

new power control algorithm V9

V12

powerControl Power Control Algorithms

nFRRequestedCodec V14 handOverControl AMR Handover mechanisms

nHRRequestedCodec V14 handOverControl AMR Handover mechanisms

noOfBlocksForAccessGrant V7 bts Paging command Process

noOfMultiframesBetweenPaging V7 bts Paging command Process

notAllowedAccessClasses V7 bts Barring of access class

numberOfPwciSamples V14 handOverControl Automatic cell tiering

numberOfSlotsSpreadTrans V7 bts Request access command repetition process

numberOfTCHFreeBeforeCongestion V9 bts Barring of access class


numberOfTCHFreeToEndCongestion V9 bts Barring of access class


numberOfTCHQueuedBeforeCongestion V9 bts Barring of access class Handover for traffic reasons

numberOfTCHQueuedToEndCongestion V9 bts Barring of access class


offsetLoad V12 adjacentCellHandover Handover decision according to adjacent cellpriorities ans load

offsetPriority V12 adjacentCellHandover Handover decision according to adjacent cellpriorities ans load

offsetPriorityUTRAN V17 adjacentCellUTRAN GSM to UMTS handover

otherServicesPriority V7 bts TCH Allocation and Priority

Queuing

pagingOnCell V9 bts PCH and RACH channel control

pcmErrorCorrection V12 bts PCM Error Correction

penaltyTime V8 bts Selection, Reselection Algorithms




Nortel confidential


powerBudgetInterCell V7 handOverControl Handovers screening

Power budget formula


powerControlIndicator V7 bts Power Control Algorithms

powerIncrStepSizeDL V14 powerControl Power Control Algorithms

powerIncrStepSizeUL V14 powerControl Power Control Algorithms

powerRedStepSizeDL V14 powerControl Power Control Algorithms

powerRedStepSizeUL V14 powerControl Power Control Algorithms

preemptionAuthor V15 signallingPoint eMLPP Preemption

pRequestedCodec V14 handOverControl AMR Handover mechanisms

preSynchroTimingAdvance V10 adjacentCellHandOver Pre-synchronized HO

priority V7 transceiver

processorLoadSupConf V8

V12

bsc BSC Overload Management Mechanisms

pwciHreqave V14 handOverControl Automatic cell tiering

minTimeQualityIntraCellHO V14 handOverControl Protection against Intracell HO Ping-Pong

AMR Handover mechanisms

qsearchC V17 handOverControl Enhanced Measurement Reporting



radChanSelIntThreshold V8 handOverControl Interference Management

radioLinkTimeout V7 bts Radio link failure process

radResSupBusyTimer V8 bsc

radResSupervision V8 bts

radResSupFreeTimer V8 bsc

reportTypeMeasurement V17 bts Enhanced Measurement Reporting


retransDuration V8 bts

rlf1 V8 bts Radio link failure process



rNCId V17 adjacentCellUTRAN GSM to UMTS handover

rndAccTimAdvThreshold V8 bts Request access command process

runCallClear V7 bts Call Clearing Process

runHandOver V7 bts Handovers

Microcellular Algo

Protection against RunHandover=1

runPwrControl V7 bts Power Control Algorithms

AMR Power Control

rxLevAccessMin V7 bts Selection, Reselection Algorithms

rxLevDLIH V7 handOverControl Intracell Handover decision for signal quality

rxLevDLPBGT V11 adjacentCellHandOver Handovers screening

Maximum RxLev for Power Budget

rxLevDLPbgtUTRAN V17 adjacentCellUTRAN GSM to UMTS handover

rxLevHreqave V7 handOverControl Measurement Processing

rxLevHreqaveBeg V11 handOverControl Early HandOver Decision


Fast power control at TCH assignment

rxLevHreqt V7 handOverControl Measurement Processing




Nortel confidential


rxLevMinCell V7 adjacentCellHandOver General formulas

Handovers screening


rxLevMinCellUTRAN V17 adjacentCellUTRAN GSM to UMTS handover

rxLevNCellHreqaveBeg V11 handOverControl Early HandOver Decision


Fast power control at TCH assignment

rxLevULIH V7 handOverControl Intracell Handover decision for signal quality

rxLevWtsList V7 handOverControl Measurement Processing

rxNCellHreqave V7 handOverControl Measurement Processing



rxQualAveBeg V14 handOverControl Automatic handover adaptation

rxQualDLIH V7 handOverControl Intracell Handover decision for signal quality

rxQualHreqave V7 handOverControl Measurement Processing rxQualHreqt V7 handOverControl Measurement Processing

rxQualULIH V12 handOverControl Intracell Handover decision for signal quality

rxQualWtsList V12 handOverControl Measurement Processing

sacchPowerOffset V16 bts Tx Power Offset for Signalling

sacchPowerOffsetSelection V16 bts Tx Power Offset for Signalling

scramblingCode V17 adjacentCellUTRAN GSM to UMTS handover

selfAdaptActivation V14 bts Automatic handover adaptation

selfTuningObs V12 handOverControl Automatic cell tiering

servingBandReporting V17 bts Enhanced Measurement Reporting


servingBandReportingOffset V17 handOverControl Enhanced Measurement Reporting GSM to UMTS handover

servingfactorOffset V14 handOverControl Automatic handover adaptation

sharedPDTCHratio V18 bts AMR Maximization , AMR Channel allocation

siteGsmFctList V7 btsSiteManager

small to large zone HO priority V9 handOverControl TCH Allocation and Priority

Queuing

smartPowerManagementConfig V17 PowerControl BTS Smart Power Management

smartPowerSwitchOffTimer V17 PowerControl BTS Smart Power Management

smsCB V7 bts SMS-Cell Broadcast

speechMode V8

V14

bts AMR - Adaptative Multi Rate FR/HR

speechMode V8

V14

signallingPoint AMR - Adaptative Multi Rate FR/HR

standard indicator AdjC V10

V12

adjacentCellHandover Dual Band Handling

standard indicator AdjC V10

V12

adjacentCellReselect Dual Band Handling

standardIndicator V12 bts Concentric/DualCoupling/DualBand CellHandover

synchronized V7 adjacentCellHandOver Pre-synchronized HO

Handover Algorithms on the Mobile Side

t3101 V9 btst3103 V9 bts




Nortel confidential


t3107 V9 bts

t3109 V9 bts

t3111 V9 bts

t3121 V17 bts GSM to UMTS handover

t3122 V9 bts

temporaryOffset V8 bts Selection, Reselection Algorithms

thresholdInterference V7 handOverControl Radio channel allocation

Interference Management

timeBetweenHOConfiguration V9

V12

bsc Power Budget Handover


timerPeriodicUpdateMS V7 bts

tnOffset V15 btsSiteManager Network Synchronization

trafficPCMAllocationPriority V9 transceiver

transceiver equipment class V9 transceiverEquipment Concentric/DualCoupling/DualBand CellHandover

transceiver equipment class V9 transceiverZone Concentric/DualCoupling/DualBand CellHandover

transceiverZone V9 transceiver Concentric/DualCoupling/DualBand CellHandover

3GAccessMinLevel V14 bts 2G - 3G Cell Reselection

3GReselectionARFCN V14 bts 2G - 3G Cell Reselection

3GReselectionOffset V14 bts 2G - 3G Cell Reselection

3GSearchLevel V14 bts 2G - 3G Cell Reselection

3GTechnology V18 bts 2G - 3G Cell Reselection

uplinkPowerControl V8 powerControl Power Control Algorithms

AMR Power Control

uRxLevDLP V7 powerControl Power Control Algorithms

uRxLevULP V7 powerControl Power Control Algorithms

uRxQualDLP V7 powerControl Power Control Algorithms

uRxQualULP V7 powerControl Power Control Algorithms

VEASDCCHOverflowAllowed V18 bts Enhanced Very Early Assignment

wPSManagement V15 bsc WPS - Wireless Priority Service

wPSQueueStepRotation V15 bts WPS - Wireless Priority Service

zone Tx power max reduction V9 transceiverZone Concentric/DualCoupling/DualBand CellHandover

zoneFrequencyHopping V9 transceiverZone Concentric/DualCoupling/DualBand CellHandover

zoneFrequencyThreshold V9 transceiverZone Concentric/DualCoupling/DualBand Cell

Handover




Nortel confidential


3.4. PARAMETERS VERSUS BSS FEATURES AND PROCEDURES

Here is the list of the main BSS tunable parameters sorted by procedure or feature.

3.4.1 2G CELL SELECTION AND RESELECTION

cellBarQualify, cellBarred, rxLevAccessMin, msTxPwrMaxCCH, cellReselInd,

cellReselectHysteresis, cellReselectOffset, temporaryOffset, penaltyTime,

rndAccTimAdvThreshold.

3.4.2 2G-3G UTRAN FDD & TDD CELL RESELECTION

3GAccessMinLevel, 3GReselectionARFCN, 3GReselectionOffset, 3GSearchLevel.

3GTechnology

3.4.3 LEGACY MEASUREMENT REPORTING

multiBandReporting, powerControlIndicator , fDDMultiratReporting, fDDreportingThreshold2 ,

qsearchC

3.4.4 ENHANCED MEASUREMENT REPORTING

multiBandReporting, reportTypeMeasurement, servingBandReportingOffset ,

servingBandReporting, fDDMultiratReporting, fDDreportingThreshold,fDDreportingThreshold2, qsearchC

3.4.5 LEVEL AVERAGING

rxLevHreqave, rxLevHreqt, rxLevWtsList, missRxLevWt, rxLevHreqaveBeg.

3.4.6 QUALITY AVERAGING

rxQualHreqave, rxQualHreqt, rxQualWtsList, missRxQualWt.

3.4.7 DISTANCE AVERAGING

distHreqt, distWtsList, missDistWt.

3.4.8 CELL ELIGIBILITY

rxLevMinCell, rxNCellHreqave, cellDeletionCount, rxLevHreqave, missRxLevWt,

msTxPwrMaxCell, msTxPwrMax, hoSecondBestCellConfiguration , rxLevNCellHreqaveBeg.




Nortel confidential


3.4.9 RADIO LINK FAILURE

radioLinkTimeOut, rlf1, rlf2, rlf3, t3111, t3109.

3.4.10 INTERFERENCE MANAGEMENT

averagingPeriod, thresholdInterference, radChanSelIntThreshold.

3.4.11 PCH AND RACH CONTROL PARAMETERS

delayBetweenRetrans, maxNumberRetransmission , nbOfRepeat, noOfBlocksForAccessGrant ,

noOfMultiframesBetweenPaging , numberOfSlotsSpreadTrans, pagingOnCell, retransDuration,

t3122, gprsNetworkModeOperation, bssPagingCoordination.

3.4.12 CONCENTRIC CELL

concentric cell, concentAlgoExtMsRange, concentAlgoExtRxLev, concentAlgoExtRxLevUL,

concentAlgoIntMsRange, concentAlgoIntRxLev, concentAlgoIntRxLevUL,

directAllocIntFrRxLevDL , directAllocIntFrRxLevUL , transceiverEquipmentClass ,

transceiverZone, zoneFrequencyHopping, zoneFrequencyThreshold, small to large zone HO

Priority, zone Tx power max reduction, biZonePowerOffset, biZonePowerOffset(n),

rxLevMinCell(n).

3.4.13 EXTENDED CELL

extended cell, rndAccTimAdvThreshold, msRangeMax, callClearing, channelType.

3.4.14 QUEUING AND PRIORITY MANAGEMENT

allocPriorityTable, allocPriorityTimers, allocPriorityThreshold , allocWaitThreshold,

allOtherCasesPriority, answerPagingPriority, assignRequestPriority, bscQueuingOption,

callReestablishmentPriority, emergencyCallPriority, interCellHOExtPriority,

interCellHOIntPriority, intraCellHOIntPriority, otherServicesPriority, small to large zone HO

Priority, directedRetryPrio, intraCellQueuing.

3.4.15 EMLPP PREEMPTION

preemptionAuthor .

3.4.16 SMS-CB

smsCB, noOfBlocksForAccessGrant , channelType.




Nortel confidential


3.4.17 FREQUENCY HOPPING

btsIsHopping, hoppingSequenceNumber , maio, siteGsmFctList, cellAllocation,

mobileAllocation, fhsRef , bscHopReconfUse, btsHopReconfRestart, btsThresholdHopReconf ,

zoneFrequencyHopping, zoneFrequencyThreshold.

3.4.18 DYNAMIC BARRING OF ACCESS CLASS

bscMsAccessClassBarringFunction, btsMsAccessClassBarringFunction,

accessClassCongestion, numberOfTCHFreeBeforeCongestion ,

numberOfTCHFreeToEndCongestion , numberOfTCHQueuedBeforeCongestion ,

numberOfTCHQueuedToEndCongestion, notAllowedAccessClasses.

3.4.19 DTX

dtxMode, cellDtxDowlink.

3.4.20 UPLINK POWER CONTROL

uplinkPowerControl, new power control algorithm, runPowerControl, , powerIncrStepSizeUL,

powerRedStepSizeUL, lRxQualULP, uRxQualULP, lRxLevULP, uRxLevULP, msTxPwrMax,

msTxPwrMax2ndBand.

3.4.21 DOWNLINK POWER CONTROL

bsPowerControl, new power control algorithm, runPwrControl, powerIncrStepSizeDL,

powerRedStepSizeDL, lRxQualDLP, uRxQualDLP, lRxLevDLP, uRxLevDLP.

3.4.22 DIRECTED RETRY HANDOVER

interBscDirectedRetry, intraBscDirectedRetry, interBscDirectedRetryFromCell,

intraBscDirectedRetryFromCell, modeModifyMandatory, directedRetryModeUsed,

msTxPwrMaxCell, msTxPwrMax, directedRetry, adjacent cell umbrella ref , directedRetryPrio.

3.4.23 UPLINK INTRACELL HANDOVER

intraCell, intraCellSDCCH, runHandOver , rxLevULIH, lrxQualULH, rxQualULIH.

3.4.24 DOWNLINK INTRACELL HANDOVER

intraCell, intraCellSDCCH, runHandOver , rxLevDLIH, lRxQualDLH, rxQualDLIH.

3.4.25 INTERCELL HANDOVER ON BAD UPLINK QUALITYCRITERION

handOver from signalling channel, runHandOver , lrxQualULH, hoMarginRxQual.




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3.4.26 INTERCELL HANDOVER ON BAD DOWNLINK QUALITYCRITERION

handOver from signalling channel, runHandOver , lRxQualDLH, hoMarginRxQual.

3.4.27 INTERCELL HANDOVER ON BAD UPLINK LEVEL CRITERION

handOver from signalling channel, runHandOver , lRxLevULH, hoMarginRxLev.

3.4.28 INTERCELL HANDOVER ON BAD DOWNLINK LEVELCRITERION

handOver from signalling channel, runHandOver , lRxLevDLH, hoMarginRxLev.

3.4.29 INTERCELL HANDOVER ON POWER BUDGET CRITERION

handOver from signalling channel, runHandOver , powerBudgetInterCell , hoMargin,

rxLevDLPBGT.

3.4.30 MICROCELLULAR ALGORITHM

handOver from signalling channel, runHandOver , cellType, microCellCaptureTimer ,

microCellStability, rxNCellHreqave.

3.4.31 INTERCELL HANDOVER ON DISTANCE CRITERION

msBtsDistanceInterCell, handOver from signalling channel, runHandOver ,hoMarginDist.

3.4.32 HANDOVER FOR TRAFFIC REASONS

handOver from signalling channel, runHandOver , hoTraffic, hoMarginTrafficOffset .

3.4.33 HANDOVER DECISION ACCORDING TO ADJACENT CELL

handOver from signalling channel, runHandOver , offsetLoad, offsetPriority.

3.4.34 GENERAL PROTECTION AGAINST HO PINGPONG

hoPingpongCombination, hoPingpongTimeRejection.

3.4.35 CALL CLEARING

callClearing, runCallClear .




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3.4.47 GSM TO UMTS HANDOVER

gsmToUMTSServiceHO, earlyClassmarkSendingUTRAN , compressedModeUTRAN,

mobileCountryCodeUTRAN, mobileNetworkCodeUTRAN, locationAreaCodeUTRAN, rNCId,

cId, fDDARFCN, scramblingCode, diversityUTRAN, t3121, rxLevMinCellUTRAN,

rxLevDLPbgtUTRAN, hoMarginUTRAN, hoMarginAMRUTRAN, hoMarginRxLevUTRAN,

hoMarginRxQualUTRAN, hoMarginDistUTRAN, hoMarginTrafficOffsetUTRAN ,

offsetpriorityUTRAN, hoPingpongCombinationUTRAN, hoPingpongTimeRejectionUTRAN ,

hoRejectionTimeOverloadUTRAN

3.4.48 ADAPTATIVE FULL/HALF RATE

amrDlFrAdaptationSet, amrDlHrAdaptationSet, amrUlFrAdaptationSet, amrUlHrAdaptationSet,coderPoolConfiguration, speechMode, HRCellLoadStart, HRCellLoadEnd, frAMRPriority,

hrAMRPriority, hrPowerControlTargetMode, hrPowerControlTargetModeDl,

frPowerControlTargetMode, frPowerControlTargetModeDl, bsPowerControl,

uplinkPowerControl, pRequestedCodec, nHRRequestedCodec, nFRRequestedCodec,

amrFRIntercellCodecMThresh , amrFRIntracellCodecMThresh , amrHRIntercellCodecMThresh ,

amrHRtoFRIntracellCodecMThresh , hoMarginAMR, amriRxLevDLH, amriRxLevULH,

nCapacityFRRequestedCodec , amrDirectAllocIntRxLevDL, amrDirectAllocIntRxLevUL,

amrDirectAllocRxLevDL, amrDirectAllocRxLevUL, filteredTrafficCoefficient,

gprsPreemptionForHR.

3.4.49 WIRELESS PRIORITY SERVICE

allocPriorityTable, allocPriorityTimers, allocWaitThreshold, bscQueuingOption,

wPSManagement, wPSQueueStepRotation.

3.4.50 NETWORK SYNCHRONIZATION

btsSMSynchroMode, tnOffset, fnOffset, dARPPh1Priority, masterBtsSmId, baseColourCode

3.4.51 REPEATED DOWNLINK FACCHenableRepeatedFacchFr , enableRepeatedFacchHr

3.4.52 TX POWER OFFSET FOR SIGNALLING

facchPowerOffset, sacchPowerOffset, sacchPowerOffsetSelection

3.4.53 NOVEL ADAPTIVE RECEIVER

adaptiveReceiver




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3.4.54 A5/3 ENCRYPTION ALGORITHM

cypherModeReject, encrypAlgoAssComp, encrypAlgoCiphModComp, encrypAlgoHoPerf ,

encrypAlgoHoReq, encryptionAlgorSupported , layer3MsgCyphModComp

3.4.55 BTS SMART POWER MANAGEMENT

smartPowerManagementConfig , smartPowerSwitchOffTimer

3.4.56 ENHANCED VERY EARLY ASSIGNMENT

EATrafficLoadEnd, EATrafficLoadStart, VEASDCCHOverflowed

3.4.57 AMR MAXIMIZATION

fullHRCellLoadEnd, fullHRCellLoadStart, sharedPDTCHratio




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4. ALGORITHMS

4.1. INTRODUCTION

This chapter describes major BSS GSM algorithms using OMC-R algorithm parameters, both

on the BTS and the MS side.

4.2. CONVENTIONS AND UNITS

In this chapter, the following abbreviations are used:

• RXQUAL_DL: weighted average for DL signal quality (MS measurements)

• RXQUAL_UL: weighted average for UL signal quality (BTS measurements)• RXLEV_DL: weighted average for DL signal strength (MS measurements)

• RXLEV_UL: weighted average for UL signal strength (BTS measurements)

• MS_BS_Dist: weighted average of MS distance from BTS (MS timing

advance)

• RXLEV_NCELL(n): arithmetic average for signal strength on neighbor cell

(reported by the MS)

4.2.1 UNIT

Thresholds on signal quality are given in RXQUAL values. Samples measurements are also

reported in RXQUAL values. When internal calculations are performed, RXQUAL values are

converted into bit error rates (BER) using mean values and compared to thresholds which are

also converted into bit error rate. From the V9 BSS release, the comparison is done with the

upper or the lower limit of the BER range.

RxQual value BER range value Mean BER value

0 BER < 0.2% 0.14%

1 0.2% < BER < 0.4% 0.28%

2 0.4% < BER < 0.8% 0.57%

3 0.8% < BER < 1.6% 1.13%

4 1.6% < BER < 3.2% 2.26%

5 3.2% < BER < 6.4% 4.53%

6 6.4% < BER < 12.8% 9.05%

7 12.8% < BER 18.10%

Signal strength thresholds are given in dBm (from -110 dBm to -47 dBm).

Signal strength measurements reported by the mobiles and the BTS are given in the rxlev

format (from 0 to 63).

The average signal strength measurement values, which are compared to the rxlev

thresholds, are the integer part of the average result.




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4.2.2 PHASE 2 BTS AND MS MAXIMUM TRANSMITTING OUTPUT POWERS

MOBILE PHASE 2 MAXIMUM TRANSMITTING OUTPUT POWER

PowerClass

GSM 850 / GSM 900

Nominal MaximumOutput Power

DCS 1800


PCS 1900


Tolerance forcondition

Normal Extreme

1 restricted MS Phase 1 1W (30 dBm) 1W (30 dBm) +/- 2 dB +/- 2,5 dB

2 8W (39 dBm) 0,25W (24 dBm) 0,25W (24 dBm) +/- 2 dB +/- 2,5 dB

3 5W (37 dBm) 4W (36 dBm) 2W (33 dBm) +/- 2 dB +/- 2,5 dB

4 2W (33 dBm) +/- 2 dB +/- 2,5 dB

5 0,8W (29 dBm) +/- 2 dB +/- 2,5 dB

ASSOCIATED POWER CONTROL LEVELS

GSM 850 / GSM 900

Powercontrol

level

NominalOutputpower(dBm)

Tolerance(dB) for

conditions

N E0-2 39 ± 2 ± 2,5

3 37 ± 3 ± 4

4 35 ± 3 ± 4

5 33 ± 3 ± 4

6 31 ± 3 ± 4

7 29 ± 3 ± 4

8 27 ± 3 ± 4

9 25 ± 3 ± 4

10 23 ± 3 ± 4

11 21 ± 3 ± 4

12 19 ± 3 ± 4

13 17 ± 3 ± 4

14 15 ± 3 ± 4

15 13 ± 3 ± 4

16 11 ± 5 ± 6

17 9 ± 5 ± 6

18 7 ± 5 ± 6

19-31 5 ± 5 ± 6

DCS 1800

Powercontrol

level


Tolerance(dB) for

conditions

N E29 36 ± 2 ± 2,5

30 34 ± 3 ± 4

31 32 ± 3 ± 4

0 30 ± 3 ± 4

1 28 ± 3 ± 4

2 26 ± 3 ± 4

3 24 ± 3 ± 4

4 22 ± 3 ± 4

5 20 ± 3 ± 4

6 18 ± 3 ± 4

7 16 ± 3 ± 4

8 14 ± 3 ± 4

9 12 ± 4 ± 5

10 10 ± 4 ± 5

11 8 ± 4 ± 5

12 6 ± 4 ± 5

13 4 ± 4 ± 5

14 2 ± 5 ± 6

15-28 0 ± 5 ± 6

PCS 1900

Powercontrol

level


Tolerance(dB) for

conditions

N E22-29 Reserved

30 33 ± 3 ± 4

31 32 ± 3 ± 4

0 30 ± 3 ± 4

1 28 ± 3 ± 4

2 26 ± 3 ± 4

3 24 ± 3 ± 4

4 22 ± 3 ± 4

5 20 ± 3 ± 4

6 18 ± 3 ± 4

7 16 ± 3 ± 4

8 14 ± 3 ± 4

9 12 ± 4 ± 5

10 10 ± 4 ± 5

11 8 ± 4 ± 5

12 6 ± 4 ± 5

13 4 ± 4 ± 5

14 2 ± 5 ± 6

15 0 ± 5 ± 6

16-21 Reserved




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BASE STATION PHASE 2 MAXIMUM TRANSMITTING OUTPUT POWERS

GSM 850 / GSM 900 GSM 1800 / GSM 1900 Tolerance for condition

Normal ExtremeCLASS 1: [320 - 640[ W [55 - 58[ dBm CLASS 1: [20 - 40[ W [43 - 46[ dBm +/- 2 dB +/- 2,5 dB

CLASS 2: [160 - 320[ W [55 - 58[ dBm CLASS 2: [10 - 20[ W [40 - 43[ dBm +/- 2 dB +/- 2,5 dB

CLASS 3: [80 -160[ W [49 - 52[ dBm CLASS 3: [5 - 10[ W [37 - 40[ dBm +/- 2 dB +/- 2,5 dB

CLASS 4: [40 - 80[W [46 - 49[ dBm CLASS 4: [2.5 - 5[ W [34 - 37[ dBm +/- 2 dB +/- 2,5 dB

CLASS 5: [20 - 40[ W [43 - 46[dBm +/- 2 dB +/- 2,5 dB

CLASS 6: [10 - 20[ W [40 - 43[ dBm +/- 2 dB +/- 2,5 dB

CLASS 7: [5 - 10[ W [37 - 40[ dBm +/- 2 dB +/- 2,5 dB

CLASS 8: [2.5 - 5[ W [34 - 37[ dBm +/- 2 dB +/- 2,5 dB

Settings will be provided to allow output power to be reduced from its maximum level to at

least six steps of nominally 2 dB with an accuracy of ≈1 dB to allow a fine adjustment of the

coverage by the network operator. In addition, the actual absolute output power at each static

RF power step (N) shall be 2*N dB below the absolute output power at static RF power step 0

with a tolerance of ≈3 dB under normal conditions and ≈4dB under extreme conditions. The

static RF power step 0 will be the actual output power according to the TRX power class.




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4.2.3 GSM PRODUCTS SENSITIVITY AND POWER

Please refer to the following documents for information on main RF characteristics of the

Nortel BTS portfolio :

BTS S2000L Engineering Rules : [R47]

BTS S2000H Engineering Rules : [R48]

BTS S4000 Outdoor Engineering Rules : [R49]

BTS S4000 Indoor Engineering Rules : [R50]

BTS eCell Engineering Rules : [R51]

BTS S8000-S8003 Indoor & S8000 Outdoor Engineering Rules : [R52]

BTS S12000 Indoor & Outdoor Engineering Rules : [R53]

BTS 18000 Indoor & Outdoor Engineering Rules : [R54]

BTS 18000 GSM-UMTS Indoor & Outdoor Engineering Rules : [R55]

BTS 6000 GSM Indoor & Outdoor Engineering Rules : [R56]




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4.2.4 CONVERSION RULES

POWER CONVERSION

The main power conversion rules are provided below.

P (dB) = P (dBW) = 10 log (PW)

P (dBm) = P (dBmW) = 10 log (PmW)

P (dB) = P (dBm) - 30

E (dBV / m) = P (dBm) + 20 log FHz + 77,2

DISTANCE - TIMING ADVANCE CONVERSION

The table below gives the conversion rules of the timing advance versus the distance.

One bit corresponds to 554 m and the accuracy is 0.25 bit (i.e 138.5 m)

Timing Advance Distance (m) Recommendation accuracy

0 [0..554[ 25 %

1 [554..1108[ 12.5 %

2 [1108..1662[ 6.1 %

3 [1662.. 3.1 %

…63 [34 902..35456[ 0.4 %

Due to multipath and to MS synchronization accuracy, the gap of timing advances between

two different MS for a given distance can reach 3 bits (i.e. 1,6 km).

The value of the timing advance has an impact on decision taking for handover and call

clearing. The timing advance is calculated by taking into account all the rays coming from a

same signal.

The timing advance must be used carefully as a handover and call clearing criteria, especially

in a microcellular configuration.

4.2.5 ACCURACY RELATED TO MEASUREMENTS

The GSM recommendation specifies the absolute and relative accuracy of the MS and BTS

measurements (Rec. GSM 05.08 § 8.1.2). The table below provides the GSM absolute

accuracy recommendation.

MS and BTS absolute measurement accuracy

from - 110 dBm to - 70 dBm under normal conditions +/- 4 dB

from - 110 dBm to - 48 dBm under normal conditions +/- 6 dB

from - 110 dBm to - 48 dBm under extreme conditions +/- 6 dB




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The overlap between the different ranges (see above normal condition cases) are specified in

the recommendation.

This recommendation is not restrictive and most of the BTS and MS may provide better

results. However, these figures show that the threshold accuracy handover and power

control field strength may be off by a few dB.

The relative accuracy depends on the gap between measurement levels and sensivity levels.

The table below provides the GSM relative accuracy recommendation of a difference between

two measurements lower than 20 dB.

MS and BTS absolute measurement accuracy

lower measured level > sensitivity + 14 dB + 2 / - 2 dB

sensitivity + 14 dB> lower measured level > sensitivity + 1 dB + 2 / - 3 dB

sensitivity + 1 dB > lower measured level + 2 / - 4 dB

For example, the level difference between two field strengths, which are higher than the

sensivity + 14 dBm, must be within the range of [-2 dB to +2 dB].

Output power tolerance must also be considered in the parameters setting because the

parameters bsTxPwrMax and msTxPwrMax are used in the algorithms.

4.2.6 FREQUENCY BAND

Frequency band Fl(n) [lower band] n range Fu(n) [upper band]

P-GSM 900 Fl(n) = 890 + 0,2 * n 1 ≤ n ≤ 124 Fu(n) = Fl(n) + 45

E-GSM 900

Fl(n) = 890 + 0,2 * n

Fl(n) = 890 + 0,2 * (n - 1024)

0 ≤ n ≤ 124

975 ≤ n ≤ 1023 Fu(n) = Fl(n) + 45

R-GSM 900Fl(n) = 890 + 0,2 * n

Fl(n) = 890 + 0,2 * (n - 1024)

0 ≤ n ≤ 124

955 ≤ n ≤ 1023Fu(n) = Fl(n) + 45

DCS 1800 Fl(n) = 1710,2 + 0,2 * (n - 512) 512 ≤ n ≤ 885 Fu(n) = Fl(n) + 95

PCS 1900 Fl(n) = 1850,2 + 0,2 * (n - 512) 512 ≤ n ≤ 810 Fu(n) = Fl(n) + 80

GSM 450 Fl(n) = 450,6 + 0,2 * (n - 259) 259 ≤ n ≤ 293 Fu(n) = Fl(n) + 10

GSM 480 Fl(n) = 479 + 0,2 * (n - 306) 306 ≤ n ≤ 340 Fu(n) = Fl(n) + 10

GSM 850 Fl(n) = 824,2 + 0,2 * (n - 128) 128 ≤ n ≤ 251 Fu(n) = Fl(n) + 45

GSM 750 Fl(n) = 747,2 + 0,2 * (n - 438) 438 ≤ n ≤ 511 Fu(n) = Fl(n) + 30

Frequencies are in MHz.




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4.3. 2G CELL SELECTION AND RESELECTION

4.3.1 OVERVIEW

NETWORK SELECTION

At switch-on, the mobile is required to select, among a set of PLMNs that is further defined

below, the highest priority PLMN that is both :

• "available"

• and "allowable"

An available PLMN is a PLMN on which a cell has been found that is not barred and where

Rxlev > rxLevAccessMin

An allowable PLMN is a PLMN which is not in the list of "forbidden PLMNs" in the MS.

The set of possible PLMNs and their decreasing order of priority is :

• the last PLMN on which the MS performed a successful registration (Location area

update);

• the Home PLMN (this is the PLMN where the MCC and MNC of the PLMN identity

match the MCC and MNC of the IMSI);

• other PLMNs, in the order explicitely defined in the SIM.

This order of priority is valid, whether the MS is a roamer or not.

CELL SELECTION PROCEDURE:

• The selection process begins with a signal strength measurement averaging on the

whole frequency band lasting approximately three seconds in order to sort channels

according to their strength.

• Then, for the most powerful channel, the MS tries to detect the FCH channel, then

decodes the SCH channel, and if the MNC and MCC are not forbidden, it listens to

SYSTEM INFORMATION 1 to 4 to get full information on that cell and possibly select

it depending on the selection criterion.

• If one of the steps fails, the next powerful channel is tried and so on.




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CELL RESELECTION PROCEDURE:

• Reselection criteria are calculated every 5 to 60 seconds period (depending on the

number of cells for which BCCH is in BCCH Allocation and number of multiframes

between paging) because MS must perform at least 5 measurements on every cell

listed in the BCCH Allocation before averaging is allowed. For phase 1 MS, C1 path

loss criterion is used whereas for phase 2 MS, the C2 criterion is used.

• Then, for the most powerful channel, the MS attempts to detect the FCH channel, then

decodes the SCH channel, and if the NCC and BCC are not forbidden, it will listen to

SYSTEM INFORMATION 1 to 4 to get full information on that cell and possibly select

it depending on the selection criterion.

4.3.2 SELECTION OR RESELECTION BETWEEN CELLS OFCURRENT LOCATION AREA

In Phase 1, MS checks that cellBarred flag is not set to “barred” before sorting eligible cells.

In Phase 2, MS checks cellBarred and cellBarQualify flags in order to define the cell’s access

(normal,low,barred).

C1 is the path loss criterion for unbarred cells of allowed PLMN.

To be selected, a cell must have a positive C1:

C1 = RXLEV - rxLevAccessMin - Max (B,0) >0with B = msTxPwrMaxCCH - P

P = maximum RF output power of the MS

Received levels must be higher than rxlevAccessMin and if a mobile state has a classmark

lower than msTxPwrMaxCCH, it must get closer to the cell to have access to it.

4.3.3 RESELECTION TO A CELL OF A DIFFERENT LOCATION AREA

This is an additionnal criteria for reselection towards a “y” cell having a different Location Areafrom the current one. A choice must be made between C1 values for cell having a different

Location Area:

C1(x) < C1(y) - cellReselectHysteresis

The value used for the parameter cellReselectHysteresis is the-one set in the current serving

cell.




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4.3.4 ADDITIONAL RESELECTION CRITERION (FOR PHASE 2)

In Phase 2, MS checks cellBarred and cellBarQualify flags in order to define the cell’s access

(normal, low, barred).

To activate this feature, the cellReselInd parameter will be set to “true”.

The C1 criterion did not provide a way of preventing a fast moving mobile station from

reselecting a “fugitive cell” nor avoiding ping-pong reselection. The idea is to give a cell a

tunable access for reselection and to prevent mobiles from reselecting a cell if that cell is new

to the mobile or if it was recently the serving cell:

C2 = C1 + cellReselectOffset - temporaryOffset * H (penaltyTime - t)

for penaltyTime ≠ 640

C2 = C1 - cellReselectOffset

for penaltyTime = 640

where t is a timer started as soon as a cell enters the mobile best cell list:

• t = penaltyTime if the new cell in the list is the previous serving

cell

• t = 0 otherwise

and H(x) is a function:

• H(penaltyTime - t) = 0 if t ≥ penaltyTime

• H(penaltyTime - t) = 1 if t < penaltyTimetemporaryOffset is a negative offset.

By adding an offset (cellReselectOffset) it is possible to give different priorities, for example, to

different types of cells in case of a multilayer network or to different bands when multiband

operation is used.

The timer penaltyTime ensures that the mobile will reselect a cell which has been received

with a sufficient level for a sufficient time. Some microcellular handover algorithms are based

on this C2 reselection principle.




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Priority of access: cellBarred and cellBarQualify parameters.

The parameters are used to give each cell the authorization to be selected or reselected, and

for all of them a priority of access is given.

The selection procedure is mainly concerned by this priority introduction.

SELECTION

For the server cell and the neighboring cells, the C1 algorithm is computed. The C2 algorithm

is computed only if cell reselection is used (cellReselInd = true).

A priority is affected to each eligible cell and is only applied to Phase II MS.

IF cellBarQualify = TRUE THEN the cell priority is “low”, whatever the “cellBarred” value is.

IF cellBarQualify = FALSE AND IF the cell is barred (cellBarred set to “barred”) THEN the cell

priority is null (the cell can not be reselected in idle mode).

IF cellBarQualify = FALSE AND IF the cell is not barred THEN the priority is “normal”.

For a mobile Phase II: if no cell with NORMAL priority is eligible (cell contained in the eligible

list constituted using the C1 algorithm), then the cells with LOW priority are scanned. So even

if a cell is barred, a phase II mobile is able to select this cell, but it will not be able to perform a

call on it.

For a mobile Phase I: it is not possible to reselect a cell that is barred.




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cellBarred cellBarQualify Priority

barred false no selection possible

barred true low

not barred false normal

not barred true low

Note: To forbid the access of a cell to a MS, the cellBarred set to “not barred” and

incomingHandover set to ”disabled”, is not sufficient. Care must be taken with the

cellBarQualify that gives the priority.

RESELECTION

There is only one kind of priority which is NORMAL.

IF the cell is barred

AND IF cellBarQualify is false

THEN the reselection is not authorized.

cellBarred cellBarQualify Priority

barred false no selection possible

barred true normal

not barred false normal

not barred true normal




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4.4. 2G - 3G UTRAN FDD & TDD CELL RESELECTION

As 3G is deployed, if GSM access network does not provide "GSM to UMTS mobility" for

mobiles in idle mode, all the dual-mode mobiles (e.g. mobile supporting both GSM andUTRAN/FDD radio access technologies) will be stuck on GSM cells:

• when leaving UMTS coverage the mobile will reselect a GSM cell

• when on a GSM cell a dual-mode mobile will only reselect a GSM cell

• switching off-on the mobile will not make the mobile reselect UMTS, since

the mobile is first looking for its last "Registered technology" at power on

• using a different PLMN for UMTS (being the mutimode subscriber HPLMN)

and GSM layers can help, but this will not work for the operators not taking

this option

The cell reselection GSM to 3G technology (FDD or TDD) does not require any specific

algorithm in the GSM-BSS. The intersystem reselection only requires pieces of information to

be broadcast on the BCCH by the GSM-BSS:

• intersystem cell reselection control parameters (as described later in the

document)

• neighboring 3G cell list

The broadcast of this information is ensured using the "System Information 2quater" message

Since 3G technology based on FDD or TDD are very closed from a BSS point of view, in V18

a new O&M parameter is available in order to select the 3G technology (FDD or TDD which

are of course exclusive) and configure up to 4 UTRAN ARFCN (TDD or FDD) with appropriate

intersystem cell reselection control parameters. Then the BSC is able to build the SI 2quater

message accordingly.

4.4.1 UE ALGORITHM IN GSM CIRCUIT MODE

Instead of the C2 criterion used in GSM only network, the multimode cell reselection uses a

criteria based on RLA_C (Received Level Averages for Circuit services), which is an

unweighted average of the received signal levels measured in dBm.

The UE starts measuring 3G cells when RLA_C in serving cell is below or above Qsearch_I(depending on the value of Qsearch_I), the MS starts measuring 3G cells (FDD or TDD).

Main reason is to save mobile battery.

UTRAN/FDD NEIGHBORING CELL RESELECTION

The UTRAN/FDD neighbouring cell n is reselected by the UE if the 2 following conditions are

met for a period of 5s:

1. (CPICH_RSCP(n) > RLA_Cserving + FDD_Qoffset)

2. (CPICH Ec/No)(n) ≥ FDD_Qmin – FDD_Qmin_Offset




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PROCESS IN THE BSS

The intersystem reselection requires new information to be broadcast on the BCCH

via "System Information 2quater" message:

• new intersystem cell reselection control parameters (as described above)

• neighboring 3G cell list

The broadcast of this new information is ensured using the "System Information 2quater"

message.

When the information is updated (following a change at the OMC-R), the CHANGE MARK bit

is set to a new value.

The System Information 2quater is scheduled either on Normal or Extended BCCH (seechapter SI2Quater & SI13 on Extended or Normal BCCH):

• If sent on Normal BCCH:

it shall be sent when TC = 5 if neither of 2bis and 2ter are used

otherwise it shall be sent at least once within any of 4 consecutive

occurrences of TC = 4

• If sent on BCCH Ext, it is sent at least once within any of 4 consecutive

occurrences of TC = 5

As a consequence, System Information 3 message has been updated in order to indicate to

the mobile:

• whether or not SI2quater is broadcast

• if broadcast is done on Normal or Extended BCCH

4.4.2 3G NEIGHBOURING CELL INFORMATION IN SI2QUATER

The GSM standard offers different possibilities to broadcast 3G neighbouring cell information

using SI2quater:

• 1) The BSS broadcast FDD_ARFCN or TDD_ARFCN and primary scrambling

code for each of the UMTS FDD neighbouring cells.

• 2) for each ARFCN, a list of scrambling codes

In this version, neighboring cell scrambling codes are not broadcast, and FDD / TDD

technologies are exclusive (either TDD or FDD ARFCN are broadcast).

Therefore, 3G neighboring cells will be described by up to 4 FDD or TDD AFRCN following 3G

technology selected.

This limitation of 4 ARFCN (TDD or FDD) is due to the fact that the System Information

2quater message segmentation is not supported in this version by the BSS.




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As it will take "some" additional time with that solution (the mobile have to decode the UTRAN

FDD neighbouring cells scrambling codes) 2 additional informations are provided and used by

the network and the mobile when the mobile reports measurement in connected mode:

• a one bit 3G-BA_IND field used to correlate the measurements with a

neighbouring cell list

• a Absolute_Index_Start_EMR used for building the neighbouring cell list in the

mobile. The value of this parameter is dynamic, and depends on the number

of 2G neighbouring cells (this allows shorter Meas. Report messages from the

UE).

4.4.3 CONTROL INFORMATION IN SI2QUATER

The following Control information is broadcast by SI2quater message :

• FDD_Qoffset or TDD_Qoffset (3GReselectionOffset)

• FDD_Qmin (FDD only) (3GAccessMinLevel)

• Qsearch_I applicable for FDD and TDD (3GSearchLevel)




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4.5. LEGACY MEASUREMENT REPORTING

4.5.1 PRINCIPLE

Legacy measurement reporting consists in a mobile in dedicated mode - on a TCH or an

SDCCH - sending downlink signal measurements to the network, at regular intervals.

The BSS then uses these measurements in the uplink power control and handover

procedures.

4.5.2 NEIGHBOUR CELL MONITORING

DOWNLINK SIGNAL STRENGTH MEASUREMENTS

In this entire section, the mobile is assumed to be in dedicated mode.

While in dedicated mode, the mobile performs signal strength monitoring on all declared

neighbouring BCCH carriers. Signal strength measurements are done in every TDMA frame

on at least one of the BCCH carriers indicated in the BCCH allocation (BA), one after another.

As an exception, a dual-mode MS may omit GSM measurements during up to 9 TDMA frames

per SACCH multiframe and use these periods for measurements on UMTS.

Furthermore, an MS on SDCCH is allowed to schedule the measurements freely within the

multiframe as long as the total number of measurement samples is maintained and the

samples on each carrier are evenly spaced.

BSIC DECODING

It is essential for the MS to identify precisely which surrounding BTS is being measured in

order to ensure reliable handover. Because of frequency re-use with small cluster sizes, the

BCCH carrier frequency may not be sufficient to uniquely identify a neighbouring cell, i.e. the

cell in which the MS is situated may have more than one surrounding cell using the same

BCCH frequency. Thus it is necessary for the MS to synchronize to and identify the base

station identification code (BSIC). The 6-bit BSIC shall be transmitted by the network on the

SCH channel of each cell.

The MS shall use at least 4 spare frames per SACCH block period for the purpose of decoding

the BSICs (e.g. in the case of TCH, the four idle frames per SACCH block period). These

frames are termed "search" frames.

The MS shall attempt to demodulate the SCH on the BCCH carrier of as many neighbouring

cells as possible, and decode the BSIC as often as possible, and as a minimum at least once

every 10 seconds.




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4.5.3 SERVING CELL MONITORING

DOWNLINK SIGNAL STRENGTH MEASUREMENTS

For each channel, the measured downlink RXLEV shall be the average of the received

downlink signal level measurement samples in dBm taken on the TCH or SDCCH channel

within the reporting period of length one SACCH multiframe.

Signal strength measurement samples shall be taken on all bursts of the physical channel that

carries the TCH or the SDCCH, including those of the SACCH.

DOWNLINK SIGNAL QUALITY MEASUREMENTS

The received downlink signal quality shall be measured by the mobile in a manner that can be

related to the average BER before channel decoding, assessed over all received bursts in themultiframe, except bursts carrying a portion of a SACCH frame.

4.5.4 REPORTING PERIOD

A measurement report contains values averaged over samples collected over 104 TDMA

frames for a TCH (480 ms = duration of 4 TCH multiframes) and 102 TDMA frames for an

SDCCH (471 ms = duration of 2 SDCCH multiframes).

The mobile sends 1 measurement report every 480 ms for a TCH, and every 471 ms for an

SDCCH. Measurements performed during that measurement period are reported on the next

SACCH block occurrence.

The transmission of a single measurement report message is done on four consecutive bursts

of the SACCH channel :

• For a TCH, there is one SACCH burst available every 120 ms.

• For an SDCCH, the 4 SACCH bursts occur in 4 TDMA frames in immediate

succession, but these 4 TDMAs in succession occur once every 471 ms.

Note : The BTS also performs uplink signal strength and uplink signal quality measurements .However, the BTS delays the processing of these uplink measurements by 480 ms or 471 ms

to ensure that they are synchronised with the downlink measurements from the mobile (i.e.

they relate to the same reporting period as the downlink measurements, which the BTS

receives with a 480 ms or 471 ms delay).

4.5.5 NEIGHBOUR CELL LISTS

Reporting with the MEASUREMENT REPORT message is usually performed on the BCCH

allocation list (i.e. GSM cells only), but could also use cells from the 3G neighbour list in the

case of 2G/3G mobiles.




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The BCCH Allocation list is provided by the network to the mobile through SI5 messages on

SACCH. The number of neighbour cell BCCH carriers in the BCCH allocation cannot exceed

32.

The UTRAN neighbour list is provided to the 2G/3G mobile through Measurement Information

messages sent on SACCH.

4.5.6 MEASUREMENT REPORT CONTENT

2G MEASUREMENT REPORT

Each measurement report contains the following data :• (neighbour cells) RXLEV_NCELL : RXLEV computed from samples taken on the

BCCH frequency of the 6 cells with the highest signal level. For each of the 6 cells, the

number of samples that is used to compute the RXLEV of that cell depends on the

total number of neighbours to be monitored (this number is the size of the BCCH

Allocation list).

• (serving cell) RXLEV_FULL : RXLEV computed from 100 (resp. 12) measurement

samples of the mobile’s TCH (resp. SDCCH). The samples are measured in each of

the 100 (resp. 12) TDMA frames that transmit either the TCH burst (resp. SDCCH) or

the SACCH burst, over the measurement period.

• (serving cell) RXQUAL_FULL : RXQUAL computed from 100 (resp. 12) measurement

samples of the mobile’s TCH (resp. SDCCH)

• (serving cell) RXLEV_SUB : For a TCH, RXLEV computed from 12 samples taken

from the 4 SACCH bursts and – in case of speech only - the 8 Silence Descriptor

(SID) frames. Not applicable for SDCCH because DTX is not allowed on SDCCH : in

that case, RXLEV_SUB = RXLEV_FULL.

• (serving cell) RXQUAL_SUB : For a TCH, RXQUAL computed from the same 12

samples as RXLEV_SUB. Not applicable for SDCCH and in that case, RXQUAL_SUB

= RXQUAL_FULL.

The mobile reports every 480 ms for a TCH and every 471 ms for an SDCCH.

3G MEASUREMENT REPORT

The measurement report is the same as for 2G, except for the RXLEV_NCELL of neighbour

UTRAN cells. The RXLEV_NCELL neighbour cell measurement is replaced by the appropriate

measurement for UTRAN. The measurement quantity reported by mobiles could be either

“CPICH RSCP” or “CPICH Ec/N0”. In Nortel implementation, mobiles are told by the network

to report only RSCP measurements on CPICH channels. However, the mobile selects the

UTRAN cells to report, based on internal measurements of the CPICH Ec/N0.




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4.5.7 MULTIBAND REPORTING

For a multi band MS the number of cells, for each frequency band supported, which must be

included in the measurement report is indicated by the value of the parameter

MULTIBAND_REPORTING, broadcast by the network in SI2ter on BCCH and SI5ter onSACCH.

The value of this parameter is set by the BSS parameter multiBandReporting (class 3, bts

object) :

• Value 0 : reporting of the six strongest cells, irrespective of the band used. No band is

favoured.

• Value 1, 2 or 3 : reporting of the 1, 2 or 3 strongest neighbour cell(s) in the non-

serving band. The remaining positions in the measurement report shall be used for

reporting of cells in the band of the serving cell. If there are still remaining positions,

these shall be used to report the next strongest identified cells in the other bandsirrespective of the band used.

4.5.8 UTRAN CELL REPORTING USING LEGACY MEASUREMENTREPORTS (V17)

If GSM to UMTS Handover feature is enabled (see §4.8.24), the network may request the

2G/3G mobiles to report on UTRAN cells as well as on GSM cells, using either :

• Legacy measurement reports : this option is covered in this subsection.

• Enhanced measurement reports : this option is covered in §4.6

Note that 2G only mobiles never report UTRAN cells. UTRAN cells’ reporting only concerns

2G-3G mobiles and is performed by these mobiles using normal measurement reports only

when HO 2G-3G is enabled (parameter gsmToUMTSServiceHo not equal to

gsmtoUMTSDisabled) and EMR is disabled. In that case, the network informs the 2G/3G

mobiles of the type of measurement report to be used by sending a parameter called

REPORT_TYPE (3GPP name) / reportTypeMeasurement (Nortel BSS parameter name)

which can take only 2 values : “enhanced measurement report” or “normal measurement

report”. It is sent on SACCH inside a message called MEASUREMENT INFORMATION.

BSS PARAMETERS

The choice criteria of 2G and 3G cells that the 2G/3G mobile must include in the Measurement

Report in the list of the 6 cells are driven by 4 network parameters, the use of which is detailed

further on in this subsection :

• fDDMultiratReporting (v17, bts object)

• fDDreportingThreshold2 (v17, handoverControl object)

• qsearchC (v17, handoverControl object)

• multiBandReporting (v10, bts object)




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If the dedicated channel (TCH or SDCCH) uses the BCCH frequency, then qsearchC is

meaningful. However, in that case, the recommended Nortel value is 7 (always search for

UTRAN cells regardless of the downlink power level of the serving cell BCCH carrier).

Conclusion : with Nortel’s recommended value qsearchC = 7, the 2G/3G mobile is required to

always search for and measure UTRAN cells, regardless of the downlink power level of the

serving cell BCCH carrier

CELL CHOICE ALGORITHM

The MS fills the normal measurement report with measurements from 6 neighbour cells

chosen in the following order :

• Strongest valid UTRAN FDD cells :

o a valid UTRAN cell is an identified cell where the primary CPICH has been

received by the mobile when using the scrambling code provided for that

frequency in the neighbour cell list.

o to be eligible, a valid cell’s Ec/N0 must also be greater than

fDDReportingThreshold2 .

o these valid and eligible cells are ranked according to the CPICH RSCP value

and the strongest are included first. The number of such reported cells is

defined by the fDDMultiratReporting parameter.

• Strongest GSM cells (including GSM cells of unknown BSIC) in each of the non-

serving frequency bands in the neighbour list. The number of such reported cells isdefined by the multiBandreporting parameter.

• Strongest GSM cells (including unknown BSIC) in the frequency band of the serving

cell. There is no limitation on the number of such reported cells.

• Remaining strongest GSM cells in each of the non-serving frequency bands in the BA

list.

• Remaining strongest UTRAN FDD cells.

Comments:

• Unlike EMR (§4.6), this algorithm does not discriminate between GSM cells with

known BSIC and GSM cells with unknown BSIC.

• Unlike EMR (§4.6), the RxLev of serving band GSM cells are not required to exceed a

reporting threshold.

• Unlike EMR (§4.6), the RSCP of UTRAN cells is not required to exceed a reporting

threshold.

• Unlike EMR (§4.6), UTRAN cells are included before GSM cells.




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ENGINEERING RECOMMENDATION

Unlike EMR, a normal measurement report contains 6 cells. Therefore, it is necessary to

exercise caution when setting the parameters fDDMultiRatReporting and multiBandReporting.

These parameters define the number of UTRAN cells and non-serving band GSM cells,repsectively, that must be included by the mobile in the list of strongest cells in the

measurement report. Therefore it leaves (6 - fDDMultiRatReporting - multiBandReporting)

spaces for the serving band cells.

Therefore, if EMR is disabled, it is recommended not to exceed fDDMultiRatReporting = 2 and

multiBandReporting = 2.

4.5.9 NOTE ON POWERCONTROLINDICATOR PARAMETER

powerControlIndicator is a BSS parameter that sets the value of the flag "PWRC". "PWRC" is

a field that is broadcast on BCCH channel inside SYSTEM INFORMATION n°3 messages.

PWRC = 1 is equivalent to powerControlIndicator = "do not include BCCH measurements"

PWRC = 0 is equivalent to powerControlIndicator = "include BCCH measurements"

The mobiles are required to interpret this flag as follows :

• if frequency hopping is not used : MS ignores the PWRC flag

• if frequency hopping is used and the BCCH frequency is not part of the Mobile

Allocation frequency list : MS ignores the PWRC flag

• if frequency hopping is used and the BCCH frequency is part of the Mobile Allocation

frequency list :

o if PWRC = 1 : in the RXLEV averaging process, the MS shall discard the

samples measured on the TCH channel's Downlink bursts that have been

transmitted by the BTS on the BCCH frequency

o if PWRC = 0 : in the RXLEV averaging process, the MS shall use the samples

measured on the TCH channel's Downlink bursts that have been transmitted

by the BTS on the BCCH frequency

In practice, in our networks :

• In case of Synthesized Frequency Hopping, there is one TRX which is dedicated to

transmitting the BCCH frequency all 8 Timeslots of the TDMA. If the BCCH frequency

was part of the hopping list of a TCH (on another TRX, of course), then there would be

systematic collisions. Therefore, in case of SFH, BCCH frequency cannot be part of

the hopping frequency list. Therefore, in case of SFH, the setting of

powerControlIndicator is irrelevant.

• In case of Baseband Frequency Hopping (BB FH is the only hopping scheme possible

with Cavity coupling), it is theoretically possible - but not recommended by Nortel - to

include the BCCH frequency in the hopping frequency list. If, in spite of ourrecommendation, the BCCH frequency is part of the hopping frequency, then :




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o if downlink power control is activated, then the TCH channel's Downlink bursts

transmitted on the BCCH frequency should not be used in the Rxlev

averaging process because, unlike the samples from other frequencies, they

are transmitted at full power : so, PWRC must be = 1 and

powerControlIndicator = "do not include BCCH measurements".

o if downlink power control is not activated, then the TCH channel's Downlink

bursts transmitted on the BCCH frequency may be used in the Rxlev

averaging process : PWRC = 0 and powerControlIndicator = "include BCCH

measurements"

4.5.10 NOTE ON RXLEV UPLINK/DOWNLINK DIFFERENCE

On the mobile side, every downlink sample is made up of measurements performed on

several bursts in dBm. On the BTS side, uplink measurements are performed in Watts. So, the

uplink RxLEv average is first computed in Watts before it is converted into dBm.

These two different ways of calculating the RxLev average yield results that are artificially

approximately 2,5 dB higher for the uplink than for the downlink (see chapter Difference

Between Uplink and Downlink Levels.




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4.6. ENHANCED MEASUREMENT REPORTING (EMR)

4.6.1 PRINCIPLE

Compared to Legacy Measurement Reporting, Enhanced Measurement Reporting allows the

mobile to:

• Report more GSM neighbouring cells and, if required, 3G cells

• Enhance the information reported about the quality of the signal received by the

mobile (MEAN_BEP and CV_BEP, downlink FER).

Enhanced Measurement Reporting by the mobile may be used in the context of 2G-3G

handover but is not a mandatory prerequisite.

4.6.2 REPORTING PERIOD

Same as Measurement Reporting.

4.6.3 ENHANCED MEASUREMENT REPORT CONTENT

The Enhanced Measurement Report contains the following information :

• (GSM neighbour cells) RXLEV computed from samples taken on the BCCH frequency

of GSM neighbour cells with the highest signal level. The number of neighbour cells to

be reported belonging to the serving GSM band on the one hand, and to the non-

serving GSM band on the other hand, depends on the values of parameters sent by

the network multibandReporting (v10 parameter), servingBandReporting (v17.0

parameter), and servingBandReportingOffset(v17.0 parameter)

• (3G neighbour cells) The reported value for 3G neighbour cells is the CPICH RSCP.

The CPICH Ec/N0 is not reported in Nortel’s current implementation. The number of

neighbour cells to be reported belonging to the 3G technology depends on the values

of parameters sent by the network fDDMultiratReporting (v17.0 parameter),

fDDreportingThreshold (v17.0 parameter) and fDDreportingThreshold2 (v17.0

parameter)

• (GSM serving cell) : The reported values for the GSM serving cell are :

o RXLEV_VAL : The average over the reporting period of RXLEV measured on

bursts whose associated FACCH, SID, or traffic frame has been the last time

slots of each fully received and correctly decoded data block and on all

SACCH frames. For speech traffic channels, blocks that have not been

erased, shall be considered as correctly decoded. For non-transparent data,

blocks are considered as correctly decoded according the CRC received. For

transparent data, all blocks are considered as correctly decoded.




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o MEAN_BEP : The average over the reporting period of the Mean Bit Error

Probability, computed from each fully received and correctly decoded data

block and from all SACCH frames.

o CV_BEP : The average over the reporting period of the Coefficient of

Variation of the Mean Bit Error Probability, computed from each fully received

and correctly decoded data block.

o RXQUAL_FULL : RXQUAL computed over the reporting period from 100

measurement samples of the mobile’s dedicated traffic channel TCH

o NBR_RCVD_BLOCKS : the number of correctly decoded TCH blocks that

were completed during the measurement report period.

4.6.4 NEIGHBOUR CELL LISTS

EMR reporting is performed on the Neighbour Cell List.

The Neighbour Cell List is the concatenation of 2 lists

• The GSM neighbour cell list

• The 3G neighbour cell list (if any)

GSM NEIGHBOUR CELL LIST

The GSM neighbour cell list is the combination of the BCCH Allocation list received in

SI5/SI5bis/SI5ter with the BSIC list received in one or more instance of the MEASUREMENT

INFORMATION message.

3G NEIGHBOUR CELL LIST

This applies only to a 2G-3G mobile. One or more instances of the Measurement Information

message may provide UTRAN Neighbour Cell Description information. This is used to build

the 3G Neighbour Cell list.

MAXIMUM LIST SIZE

In Nortel’s v17 implementation, the maximum number of cells of the lists in the Measurement

Information message is :

• maximum 32 UMTS cells

• If the 3G list is void, maximum 32 GSM cells

• If the 3G list is non-void, maximum 31 GSM cells




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4.6.5 ORDER OF REPORTING PRIORITY OF NEIGHBOUR CELLS

The Mobile includes measurement results of neighbour cells using the following priority order:

• Highest priority : the number of strongest GSM cells with known and valid BSIC in the

frequency band of the serving cell, according to the value of servingBandReporting;

• 2nd highest priority : the number of strongest GSM cells with known and valid BSIC in

each of the frequency bands in the BCCH Allocation list, excluding the frequency band

of the serving cell, according to the value of multiBandReporting;

• 3rd highest priority : the number of best valid UTRAN cells with a reported value equal

or greater than fDDReportingThreshold in the 3G neighbour cell list, according to the

value of fDDmultiRatReporting. Additionally the CPICH Ec/No shall be equal or

greater than fDDReportingThreshold2 . A valid cell is an identified cell where the

primary CPICH has been received when using the scrambling code provided for that

frequency in the neighbour cell list.• 4th highest priority : the remaining GSM cells with known and valid BSIC or, if allowed

by the flag INVALID_BSIC_REPORTING, with known and allowed NCC part of the

BSIC in any frequency band.

• Last priority : remaining valid UTRAN cells

For each of the priority levels above, the mobile shall apply the following rules :

• if the number of valid cells is less than indicated, the unused positions in the report

shall be left for cells of lower priority;

• if there is not enough space in the report for all valid cells of a given priority, cells shall

be ranked according to :

o for GSM cells belonging to the serving band : RxLev +

servingBandReportingOffset . Note that this ranking criterion shall not affect

the value that is effectively included in the report, which remains RxLev.

o for GSM cells belonging to the non-serving band : RxLev. (reporting offset =

0)

o for UTRAN cells : RSCP. (reporting offset = 0)

4.6.6 MEASUREMENT INFORMATION MESSAGE

PURPOSE OF MI MESSAGE

The activation of EMR in the network requires the network to inform the relevant mobiles that

EMR reports are expected from them.




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To do this, the network sends a new information message to the mobiles, called Measurement

Information. The Measurement Information message is regularly sent by the network to the

mobiles in dedicated mode on the SACCH, in addition to System information messages 5,

5bis, 5ter, and 6.

The following mobiles receive MI messages :

• 2G-3G mobiles that are at least Release 99

• 2G-only mobiles that are at least Release 4

CONTENT

In the version of EMR reporting currently implemented, the MI message contains essentiallythe following information :

• EMR activation flag. The value of this flag is set by the reportTypeMeasurement

parameter.

• Information enabling the mobile to derive the full list of GSM neighbour cells, i.e.

(BCCH frequency, BSIC) pairs, that may be reported in EMR reports.

• INVALID_BSIC_REPORTING : 0 for disabled, 1 for enabled. When set to 1, report on

cells with invalid BSIC and allowed NCC part of BSIC is allowed. The value 1 is

mandatory if feature “switch interference matrix” is activated.

• Number of GSM neighbour cells of the serving band that the Mobile shall include inthe list of strongest cells in the EMR report (up to 3). The value of this number is set

by the servingBandReporting parameter.

• Threshold power level above which serving band cells may be reported among the

servingBandReporting number of reported cells. In v17 implementation, this threshold

is -110 dBm, meaning that all serving band cells may be reported regardless of their

power level.

• (applicable to multi-band mobiles only) Number of GSM neighbour cells of the other

band that the Mobile shall include in the list of strongest cells in the EMR report (up to

3). The value of this number is set by the multiBandReporting parameter (v10

parameter).

• (applicable to multi-band mobiles only) Offset to apply to the reported value when

prioritizing the cells for reporting for GSM serving frequency band. The value of this

offset is set by the servingBandReportingOffset parameter

• (applicable to 2G-3G mobiles only) UTRAN neighbour cell list : list of FDD (ARFCN,

scrambling code, diversity) triplets, identifying each 3G neighbour cell. The values of

these triplets are set by the following AdjacentCellUTRAN object parameters :

o fDDARFCN,

o scramblingCode,

o diversityUTRAN




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• (applicable to 2G-3G mobiles only) UTRAN cells’ measurement parameters :

o Number of FDD cells to be reported in the list of strongest cells in the EMR

message. This number is set by the O&M network parameter

fDDMultiRatReporting.

o CPICH RSCP level above which the mobile will apply a higher priority to

UTRAN cells in the EMR message. The value of this level is set by the O&M

network parameter fDDReportingThreshold.

o CPICH Ec/N0 level above which the mobile will report UTRAN cells in the

EMR message. The value of this level is set by the O&M network parameter

fDDReportingThreshold2 .

o Serving cell BCCH frequency power threshold above which, or below which,

the mobile may search for UTRAN cells. The value of this level is set by the

O&M network parameter qsearchC.

o Type of reporting quantity (value always equal to RSCP in v17

implementation)

RELATION WITH 2G-3G HANDOVER

Note that 2 different versions of the Measurement Information message may be sent by the

network depending on the mobile’s radio access capability (2G or 2G-3G) :

• If EMR reporting is activated but not 2G-3G handover (i.e. the gsmToUMTSServiceHo

parameter is set to "gsmToUMTSDisabled") :

o the BSC only sends 2G Measurement Information to the BTS. However, the

BSC does send the whole L1M configuration to the BTS. The BTS is therefroe

aware of the UTRAN neighbouring cells.

o The BTS only sends 2G Measurement Information messages to 2G-3G

Release 99 mobiles and Release 4 2G mobiles. Thus UMTS cells are hidden

from the mobiles so that mobiles do not report 3G measurement results in

vain, which could adversely affect their performance.

• If both EMR reporting and 2G-3G handover are activated (i.e. the

gsmToUMTSServiceHo parameter is not set to "gsmToUMTSDisabled") :

o the BSC sends to the BTS both the 2G Measurement Information and the

2G/3G Measurement Information messages.

o The BTS sends the 2G/3G Measurement Information to 2G-3G Release 99

mobiles and the 2G Measurement Information to the Release 4 2G mobiles.




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4.6.7 MI/SACCH SCHEDULING

The scheduling of Mesaurement Information and System Information messages in the SACCH

channel is :

SI 5

SI5bis

SI 5ter

SI 6

MI

SI 5

... etc.

4.6.8 MAIN DIFFERENCES BETWEEN NORMAL AND ENHANCEDMEASUREMENT REPORTING

This section attempts at summarising the main differences between normal measurement

reporting (§4.5) and enhanced measurement reporting (§4.6).

MR EMR

A normal measurement report contains up to 6 neighbour cells An enhanced measurement report contains up to 32neighbour cells

No reporting offset is applied to rank cells. Competing cells areranked based only on the strongest RxLev (GSM) and RSCP(UTRAN) values

servingBandReportingOffset is applied to the RxLev of servingband GSM cells for ranking purposes. No offset is applied fornon-serving band GSM cells and UTRAN cells

One (1) reporting threshold is used to define eligible UTRANcells : fDDReportingThreshold2 for Ec/No (non-reportedquantity). No threshold for RSCP.

2 reporting thresholds are used to define eligible UTRAN cells: fDDReportingThreshold for RSCP (reported quantity) andfDDReportingThreshold2 for Ec/No (non-reported quantity)

A parameter (fDDMultiRatReporting) defines the number ofUTRAN cells to be included in the report as a matter of priority

A parameter (fDDMultiRatReporting) defines the number ofUTRAN cells to be included in the report as a matter of priority

A parameter (MultiBandReporting) defines the number of non-

serving band GSM cells to be included in the report as amatter of priority

A parameter (MultiBandReporting) defines the num ber of non-

serving band GSM cells to be included in the report as amatter of priority

There is no required minimum number of serving band GSMcells in the report

A parameter (servingBandReporting) defines the number ofserving band GSM cells to be included in the report as amatter of priority

GSM cells with known BSIC and GSM cells with unknownBSIC are treated the same

GSM cells with known and valid BSIC have higher priority

UTRAN cells have top priority in the report Sering and GSM cells have top priority in the report




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4.6.9 NEW BSS PARAMETERS

The following parameters are created in v17.0 and are needed to support Enhanced

Measurement Reporting :

Parameter name Definition Equivalent in GSM specification

fDDMultiratReporting Number of FDD UTRAN cells to be reported in the listof strongest cells in the EMR message

FDD_MULTIRAT_REPORTING

fDDReportingThreshold defines the CPICH RSCP level above which the MS willapply a higher priority to UTRAN cells in the enhancedmeasurement report message

FDD_REPORTINGTHRESHOLD

fDDReportingThreshold2 defines the CPICH Ec/N0 level above which the MS willreport UTRAN cells in the enhanced measurement

report message

FDD_REPORTINGTHRESHOLD2

qsearchC

search for UTRAN cells if signal level on BCCH ofserving cell :

is below threshold (0-7):

-98, -94, … , -74 dBm, ∞ (always)

or is above threshold (8-15):

-78, -74, … , -54 dBm, ∞ (never)

If the serving BCCH frequency is not part of theBA(SACCH) list, the dedicated channel is not on theBCCH carrier, and qsearchC is not equal to 15, the MSshall ignore the qsearchC parameter value and alwayssearch for UTRAN cells. If qsearchC is equal to 15, theMS shall never search for cells on 3G.

Qsearch_C

reportTypeMeasurement type of measurement report to be reported on this cell :enhanced measurement report or legacy measurementreport

REPORT_TYPE

servingBandReporting defines the number of cells from the GSM servingfrequency band that shall be included in the list ofstrongest cells in the measurement report.

SERVING_BAND_REPORTING

servingBandReportingOffset

If there is not enough space in the report for all validcells, the cells shall be reported that have the highestsum of the reported value (RXLEV) and the parameterservingBandReportingOffset(XXX_REPORTING_OFFSET) for the serving GSMband. Note that this parameter shall not affect the valueitself of the reported measurement.

XXX_REPORTING_OFFSET(XXX=900,1800,400,850,1900)




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4.6.10 IMPACT OF EMR ON INTERFERENCE MATRIX

IMPROVED ACCURACY

There are more GSM neighbours reported with EMR than with legacy measurement reporting

:

• With EMR, up to 32 GSM neighbours if no UTRAN cells are defined in the Neighbour

Cell List

• With standard MR, 6 neighbour cells.

This means that the statistical processing induces less systematic bias error in the case of

EMR.

GREATER NUMBER OF CYCLES

If no 3G cells are declared as neigbours, the number of cycles depends only on the number of

declared real neighbours and the number of fake neighbours, so it is not impacted by EMR.

However, if 3G cells are declared as neighbours, the maximum number of GSM neighbours

(real + fake) is 31 instead of 32. Therefore, more cycles may be required if 3G cells are

present in the Neighbouring Cell List.

CHANGE OF TRAFFIC DISTRIBUTION

If, during the Interference Matrix campaign in a dual band network, the reporting of serving

band neighbours is deliberately favoured by using the servingBandReportingOffset , then, as a

side-effect, the traffic distribution may be modified. This undesirable side-effect may in turn

modify the results of the IM measurements, whjich therefore may no longer reflect the real

situation in the field once the IM has ceased.

Therefore it is recommended to ensure that the chosen value of servingBandReportingOffset

does not cause unacceptable changes in the traffic distribution.




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4.6.11 IMPACT OF EMR ON RADIO MEASUREMENT DISTRIBUTION

(RMD)Thanks to enhanced measurement reports, the downlink FER indicator is available to the

network. Specific distributions are added for the different codec types.

Also, a distribution of estimated downlink voice quality is added. This indicator is based on the

same principle as MOS for uplink, but is a marginally less accurate because the mobile does

not provide the distribution of codecs used during the measurement period.

The post processing tool WQA is modified accordingly.

DOWNLINK FRAME ERASURE RATE

In the EMR message, the mobile provides the number of received traffic frames :

NBR_RCVD_BLOCKS. The BTS knows the number of times each codec have been used

during the measurement period so it is now possible to get a rough estimate of the probable

number of frames, per codec, that have not been decoded by the mobile and a rough

estimate, per codec, of the probable downlink FEP (Frame Erasure Probability). Note that

each sum of estimated number of bad frames is rounded to the nearest integer value at the

end of the connection.

Thanks to RMD feature, downlink FER distributions at the OMC-R level are made available

for the following types of circuit calls:

• EFR and FR speech calls,

• AMR FR speech calls,

• AMR HR speech calls.

DOWNLINK VOICE QUALITY INDICATOR

With EMR, it is possible to estimate the downlink voice quality (DVQI) in the same way as

TEPMOS estimates the uplink voice quality.

Distinction is done for the different codec types (EFR (and FR), AMR FR and AMR HR).

As the downlink FER per codec is an estimated one, the downlink voice quality indicator will

be less precise than TEPMOS, but the formula used to calculate DVQI is similar to the

TEPMOS one.




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4.7. UPLINK MEASUREMENT PROCESSING

4.7.1 PRINCIPLE

Each sample on the uplink side used by the Layer 1 Management in the average computation

is composed of measurements performed in Watts on several bursts. So the uplink samples

are first computed in Watts before being translated into dBm.

The general idea is to perform arithmetic averages. These averages are stored, and each time

a decision has to be taken, an other average (weighted-average) is computed. This weighted-

average is based on a defined number (Hreqt) of arithmetic averages, which are weighted in

order to favor the latest results.

In the new version of the Layer 1 Management (L1mV2), the process of averaging is based on

fully sliding windows.

Examples for Hreqave = 8, Hreqt = 1, run xx = 4




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Example: If r3 is missing, then r3 = r2 X weighting factor.

RULE 3

If no measurement value is available, the missing measurement is replaced by a default value.

Example: If r1 is missing, then r1 = default value.

RULE 4:

In the following, the substitution of a missing value is only done when 6 neighbouring cells are

reported during the considered period.

From L1mV2 missing measurements for neighboring cells are replaced as follows; for both

cases, inputs are:

• Ncell1 no longer belongs to the list of 6 preferred cells at T+1 period,

• T, T+1 correspond to measurement periods.

First case:

IF RxLevNCell1(T) ≤ min(RxLevNCell(T+1) of the 6 reported cells)

THEN RxLevNCell1(T+1) = RxLevNCell1(T)

r1 r2 r3 r4 r5 r6 r7 r8

m1

m2

m3

m4

m5

time

r1 r2 r3 r4 r5 r6 r7 r8

m1

m2

m3

m4

m5

time

r1 r2 r3 r4 r5 r6 r7 r8

m1

m2

m3

m4

m5

time

r1 r2 r3 r4 r5 r6 r7 r8

m1

m2

m3

m4

m5

time




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Second case:

IF RxLevNCell1(T) > min(RxLevNCell(T+1) of the 6 reported cells)

THEN RxLevNCell1(T+1) = min(RxLevNCell(T+1)) - missOffsetdB

missOffset has a fixed value of 3 dB.




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4.8. DIRECT TCH ALLOCATION AND HANDOVER ALGORITHMS

Since V14, a new version of the Layer 1 Management (L1mV2) is applicable (see chapter

Measurement Processing)

CAUTION!

It is understood in all the following formulas that RxLev_XX is computed with L1mV2.

4.8.1 GENERAL FORMULAS

PBGT

The general PBGT formula is computed in the band0 because HO_MARGIN is always specific

to the band0:

PBGT(n) = Min [msTxPwrCapability(Band0), msTxPwrMax]

- Min [msTxPwrCapabilityCell(n), msTxPwrMaxCell(n)]

+ (RxLevNCell(n)ave - RxLevDLave))

• msTxPwrCapability: maximum transmission power capability of the MS according

to the BCCH frequency (Band0) and its power class (§ 4.2.2).

• msTxPwrMax: maximum transmission power level the MS is allowed to use on a

traffic channel in the current cell.• msTxPwrMaxCapabilityCell(n): maximum transmission power capability of the MS

(in the BCCH frequency band) of an adjacent cell (n), according to:

o the BCCH frequency band of the adjacent cell (n)

o the power class of the mobile in this band (§ 4.2.2)

• msTxPwrMaxCell(n): maximum transmission power level the MS is allowed to use

on a traffic channel of neighbour cell n (or the band0 of the neighbour dual band cell n)

• RxLevNCell(n) ave: averaged downlink signal strength of the neighbour cell n

• RxLevDLave: averaged downlink signal strength of the serving cell

However, if the MS is in band1 the PBGT formula is changed.

Indeed, RxLevNCell(n)ave should be replaced by RxLevNCell(n)ave + biZonePowerOffset inorder to simulate what the field strength would be like in band0.




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EXP1

The expression named EXP1 used for defining eligible cells:

EXP1(n) = RxLevNCell(n) ave - [ rxLevMinCell(n) + Max(0, msTxPwrMaxCell(n) -

msTxPwrCapability(n) ) ]

It is also used in the following process:

EXP1Capture(n) = RxLevNCell(n) ave - rxLevMinCell(n)

EXP1DirectedRetry(n) = RxLevNCell(n) ave - [directedRetry(n) + Max(0,

msTxPwrMaxCell(n) - msTxPwrCapability(n)]

EXP1Forced HO (n) = RxLevNCell(n) ave - [forced handover algo(n) + Max(0,


• RxLevNCell(n) ave: averaged downlink signal strength of the neighbour cell n

• rxLevMinCell(n): minimum RXLEV value required for a MS to handover towards

cell n

• msTxPwrMaxCell(n): maximum transmission power level the MS is allowed to use

on a traffic channel of neighbour cell n / in the band0 of the neighbour dual band cell

• msTxPwrCapability(n): maximum transmission power capability of the MS

according to the power class of the mobile and the BCCH frequency (the band0) of the

neighbour cell n

• directedRetry(n): minimum signal strength level received by the MS to process

directed retry handovers in BTS mode

• forced handover algo(n): minimum signal strength level received by the mobiles to

be granted access to a neighbor cell in case of forced handover.

Note: If HO decision is made toward the inner zone of a multizone cell, then related

EXP1XX(n) is computed with biZonePowerOffset(n) .




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EXP2

The expression named EXP2 used for defining suitable cells:

EXP2PBGT(n) = Pbgt(n) - AdaptedHoMargin(n)

EXP2Traffic(n) = Pbgt(n) - [hoMargin(n) - hoMarginTrafficOffset(n)]

EXP2Quality(n) = Pbgt(n) - hoMarginRxQual(n)

EXP2Strength(n) = Pbgt(n) - hoMarginRxLev(n)

EXP2Distance(n) = Pbgt(n) - hoMarginDist(n)

EXP2AMR(n) = Pbgt(n) - hoMarginAMR(n)

EXP2bis(n) = rxLevDLPBGT(n) - RxLevDL ave

• AdaptedHoMargin(n): margin computed when AHA feature is enabled. It takes into

account neighDisfavorOffset and servingfactorOffset parameters (see chapter

Automatic handover adaptation)

• hoMargin(n): margin to be used for power budget HO

• hoMarginTrafficOffset(n) : offset to be applied to hoMargin(n) for traffic HO decision

(when current cell is overloaded)

• hoMarginRxQual(n): margin to be used for quality HO

• hoMarginRxLev(n): margin to be used for signal strength HO

• hoMarginDist(n): margin to be used for distance HO

• hoMarginAMR(n): margin to be used for quality intercell HO defined for AMR TCH

channels

• rxLevDLPBGT(n): maximum downlink RxLev received from serving cell to allow a

power budget or traffic HO towards this NCell

Note: If HO decision is made in the inner zone of a multizone cell, then related EXP2XX(n) is

computed with (hoMarginXX(n) + biZonePowerOffset).




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4.8.2 DIRECT TCH ALLOCATION

This chapter describes the Direct TCH Allocation feature which applies to the dualband cell,

the concentric cell and the dualcoupling cell features. Direct TCH Allocation has beenenhanced in v17.0.

PRINCIPLE

The principle of “Direct TCH Allocation” is manifold. It consists in the following aspects :

• At call setup, to allocate a FR TCH directly into the inner-zone of a multizone cell

• At call setup, to allocate an HR TCH directly into the outer-zone of a multizone cell

• At call setup, to allocate an HR TCH directly into the inner-zone of a multizone cell

• On intercell handover, to allocate a TCH directly into the inner-zone of the targetmultizone cell.

At call setup, while the mobile is still on SDCCH (SDCCH is always allocated in the large zone

of a multi-zone cell), the BSC asks the BTS if the call (FR or HR) may be directed to the

appropriate zone by sending the BTS an “Abis Connection state request” message. The

acknowledgement of this request by the BTS provides the BSC with the information allowing

the BSC to decide to perform the requested TCH allocation.

The BTS uses several criteria to decide which zone is eligible. These criteria have been

altered in v17.0 as explained in the next section.

V17.0 ENHANCEMENT PRINCIPLE

CALL SETUP

In initial phase of call establishment, the time spent on SDCCH is usually too short for the BTS

to compute a weighted average on downlink Rxlev measurement before the BST receives the

Abis connection state request from the BSC. Therefore, the allocation criteria for direct TCH

allocation use, by decreasing order of priority:

• a weighted average computed with RxLevHreqAve*RxLevHreqT latest measurements

(unlikely to happen on SDCCH).

• an arithmetic average computed with RxLevHreqAve latest measurements (unlikely to

happen on SDCCH)

• a short and fully reliable average (RxLevHreqAveBeg measurements) in the sense of

the Automatic handover Adaptation feature if this feature is enabled and if the MS is

fast enough or hopping on enough frequencies to filter the Raleigh fading.

• a short, not fully reliable average (from RxLevHreqAveBeg up to RxLevHreqAve-1

measurements) in all other cases.

In the last case, the v17 enhancement consists in the L1M compensating for the lower

reliability of the short average by adding the hoMarginBeg margin to the various allocationthresholds. For all other cases, there is no change in v17.0.




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Note : If hoMarginBeg parameter is set to 63, the Direct TCH allocation procedure only uses

normal averages.

INTERCELL HANDOVER

Some handover decisions (Early Power budget or Directed Retry) may be taken using less

than RxLevNcellHreqAve measurements on the neighbouring cell. So, the allocation

information for direct TCH allocation uses by decreasing order of priority:

• an arithmetic average computed with RxLevNcellHreqAve latest measurements.

• a short and fully reliable average (RxLevNcellHreqAveBeg measurements) in the

sense of the Automatic Handover Adaptation feature if this feature is enabled and if

the MS is going fast enough to filter the Raleigh fading

• a short not fully reliable average (from RxLevNcellHreqAveBeg up toRxLevNcellHreqAve -1 measurements) in all other cases.

In the last case, the L1M now compensates for the lower RxlevNcell average reliability by

adding the hoMarginBeg margin to the BizonePowerOffset(n) parameter in order to ensure the

same grade of service.

Note : If hoMarginBeg parameter is set to 63, inter-cell handover Direct TCH allocation

procedure only uses normal averages.

DIRECT FR TCH ALLOCATION IN INNER-ZONE, AT CALL SETUP

From V18, if using a not fully reliable short average, hoMarginBeg is added to the following

thresholds :

• DirectAllocIntFrRxlevUL

• DirectAllocIntFrRxLevDL

CONCENTRIC CELLS

The criteria for a successful direct TCH allocation in the inner-zone are:

RxLevDL > DirectAllocIntFrRxLevDL

And

RxLevUL>DirectAllocIntFrRxLevUL

and

MS_BS_Dist < concentAlgoExtMsRange (timing advance criterion)




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DUALBAND OR DUALCOUPLING CELLS

The timing advance criterion is disabled for a dualcoupling or dualband cell since the algorithmonly needs to check that the BS Tx power in the innerzone is sufficient to maintain the

communication.

For dualband cells, obviously, a test is also performed on the capability of the mobile to

support the band1.

The criterion for a successful direct TCH allocation in the inner-zone is :

RxLevDL > DirectAllocIntFrRxLevDL

And

RxLevUL>DirectAllocIntFrRxLevUL

DIRECT HR TCH ALLOCATION IN OUTER-ZONE, AT CALL SETUP

In v17, if using a not fully reliable short average, hoMarginBeg is added to the following

thresholds :

• amrDirectAllocRxLevDL

• amrDirectAllocRxLevUL

CONCENTRIC CELLS

The criteria for a successful direct HR TCH allocation in the outer-zone are :

RxLevDL > amrDirectAllocRxLevDL

and

RxLevUL > amrDirectAllocRxLevUL


The criteria for a successful direct HR TCH allocation in the outer-zone are :

RxLevDL > amrDirectAllocRxLevDL

and

RxLevUL > amrDirectAllocRxLevUL




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DIRECT HR TCH ALLOCATION IN INNER-ZONE, AT CALL SETUP

In v17, if using a not fully reliable short average, hoMarginBeg is added to the following

thresholds :

• amrDirectAllocIntRxLevDL

• amrDirectAllocIntRxLevUL

CONCENTRIC CELLS

The criteria for a successful direct HR TCH allocation in the inner-zone are :

RxLevDL > amrDirectAllocIntRxLevDL

and

RxLevUL > amrDirectAllocIntRxLevUL

and

MS_BS_Dist < concentAlgoExtMsRange (timing advance criterion)


The criteria for a successful direct HR TCH allocation in the inner-zone are :

RxLevDL > amrDirectAllocIntRxLevDL

and

RxLevUL > amrDirectAllocIntRxLevUL

DIRECT TCH ALLOCATION ON INTER-CELL HANDOVER

In v17, if using a not fully reliable short average, hoMarginBeg is added to bizonePowerOffset.

If the target cell for handover is a multi-zone cell, the BTS is in charge of indicating to the BSC

if a TCH can be allocated in the inner zone of the target cell. This information is provided in the

"additional cells information” IEI within Abis Handover indication or Connection state ack

messages :

This capability (to handover directly in the innerzone/band1 of the adjacent cell) is inhibited

when biZonePowerOffset(n) is set to 63.




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CONCENTRIC OR DUALCOUPLING CELLS

The criterion for the inner-zone of the neighbour cell to be eligible is :

RxLevNCell(n)ave > rxLevMinCell (n) + bizonePowerOffset (n) + Max(0, msTxPwrMaxCell(n) -

msTxPwrCapabilityCell(n) )

DUALBAND CELLS

The criteria for the inner-zone (band 1) of the neighbour dualband cell to be eligible are :

MS supports band 1 of NCell

and

RxLevNCell(n)ave > rxLevMinCell (n) + bizonePowerOffset (n) + Max(0, msTxPwrMaxCell(n) -msTxPwrCapabilityCell(n) )

REMARK ON OUTER TO INNER ZONE INTRA CELL HANDOVER

It should be noted that the BTS provides the same allocation information to the BSC on an

intra-cell handover initiated from a TCH belonging to the Large zone. However, no

hoMarginBeg margin applies to allocation thresholds because a Weighted average is always

available.

4.8.3 HANDOVERSEach runHandOver, after L1M initialisation process for handover, the BTS performs handover

decision process based on regular uplink and downlink measurements on the current cell

(level and quality) and neighbouring cells (level only); the main steps of this process are:

• Triggering: the BTS detects that a handover is needed by comparison with

thresholds: lRxLevXLH for alarm on level; lRxQualXLH for alarm on Quality;

msRangeMax for alarm on distance, there is no “triggering” for handover on

PBGT

• Screening: the BTS determines what are the 6 best suitable cells For the

handover (preferred cells list) and sends them to the BSC in the Handover

Indication message; to be in the preferred cells list, a cell must first be eligible

(eligibility checking) then sorted (Ncells list sorting); the preferred cells list is

an ordered list of sorted cells.

• Selecting: the BSC determines THE target cell according to the resource

found after reducing the preferred cells list to a maximum of three elements

• Executing: allocation, activation, assignment of the new channel, switching

onto this channel




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HANDOVERS TRIGGERING

Intercell handover normally occurs for two main reasons:

• Rescue handovers: when the MS gets too far from the BS (Distance) and/or

radio link measurements show low received signal strength (DL/UL signal

Strength) and/or signal quality on the current serving cell (DL/UL signal

Quality)

• Network Optimization Handovers: a better signal strength is available on an

adjacent cell (Power Budget), the serving cell gets overloaded (Traffic) or in

the particular case of a multilayer network (Capture)

Note: new intercell handover decisions have been introduced for AMR channels

Intracell handovers normally occur for the following reasons:

• Interference handover: radio measurements show a low received signal

quality but a high received signal strength on the serving cell.

• inter-zone handover from a "zone" of a multizone cell to another "zone".

• frequency tiering handover

• specific intracell handover for AMR TCH channels,

HANDOVERS SCREENING

To a given handover is associated (hard coded) a set of expressions used both to check

eligibility of a neighbour cell (a cell from the list of Ncells reported by the MS is eligible if allexpressions attached to this HO cause and neighbour cell are strictly positive) and to sort

target cells list.

See the chapter General formulas to get the detail of each expression.




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4.8.4 HANDOVERS DECISION PRIORITY

HANDOVER DECISION FUNCTIONS FOR SDCCH & TCH/F CHANNELS

The whole set of HO decision functions currently implemented for non AMR channels, with

their priority, is defined in the table below (handover functions are executed in increasing order

of priority as shown below):

HO decision function early HO intercell HO priority comment

Capture false intercell 1

UL signal quality false intercell 2

DL signal quality false intercell 3

UL signal strength false intercell 4

DL signal strength false intercell 5

Distance false intercell 6

Power Budget true intercell 7

Traffic false intercell 8 (d)

Intracell on UL signal strength & quality false intracell 9 (a) (c)

Intracell on DL signal strength & quality false intracell 10 (a) (c)

Interband HO (dualband cells) false intracell 11 (b) (c)

Interband HO (concentric cells) false intracell 11 (b) (c)

Interband HO (dualcoupling cells) false intracell 11 (b) (c)

Frequency tiering false intracell 12 (a) (c)

Directed Retry false intercell 0

(a) intracell and tiering handover functions are exclusive from each other

(b) these handover functions are exclusive from each other (a given cell may be of only one

type among concentric, dual-coupling & dual-band) and do not apply to SDCCH channels.

(c) these intracell handover functions are ihnibited when in directed retry mode.

(d) only for a monozone cell or in the large zone of a multizone cell.

Note: The so-called "Directed Retry" handover is a "pseudo" handover indication message

sent upon request from the BSC. This specific case is mainly intended to provide BSC with a

target cells list for intercell HO and is discussed in chapter Directed Retry Handover .




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HANDOVER DECISION FUNCTIONS FOR AMR TCH CHANNELS

HO decision function early HO intercell HO priority comment

Capture false intercell 1quality intercell HO on UL codec mode false intercell 2

quality intercell HO on DL codec mode false intercell 3

UL signal strength false intercell 4

DL signal strength false intercell 5

Distance false intercell 6

Power Budget false intercell 7

Traffic false intercell 8 (d)

capacity intracell HO on UL / DL codec modes false intracell 9 (b) (c)

quality intracell HO on UL codec mode false intracell 10 (b)

quality intracell HO on DL codec mode false intracell 11 (b)

Interband HO (dualband cells) false intracell 12 (a) (b)

Interband HO (concentric cells) false intracell 12 (a) (b)

Interband HO (dualcoupling cells) false intracell 12 (a) (b)

Frequency tiering false intracell 13 (b)

Directed Retry false intercell 0

(a) these handover functions are exclusive from each other (a given cell may be of only one

type among concentric, dual-coupling & dual-band).

(b) these intracell handover functions are ihnibited when in directed retry mode or in dual

tranfer mode.

(c) this intracell handover function applies to TCH/AFS (Full Rate) channels only.

(d) only for a monozone cell or in the large zone of a multizone cell.

Note: The so-called "Directed Retry" handover is a "pseudo" handover indication message

sent upon request from the BSC. This specific case is mainly intended to provide BSC with a

target cells list for intercell HO and is discussed in chapter Directed Retry Handover .




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4.8.5 DIRECTED RETRY HANDOVER

After the initial establishment procedure, if the MS is attached to a SDCCH and if there is no

TCH resource available, a directed retry handover is required.

The following parameters enable this feature:

• intraBscDirectedRetry (bsc)

• interBscDirectedRetry (bsc)

• intraBscDirectedRetryFromCell (bts)

• interBscDirectedRetryFromCell (bts)

Note: Directed Retry can be activated indepently from Queuing

DIRECTED RETRY HANDOVER: BSC (OR LOCAL) MODE

This mode is enabled by the bts object parameter directedRetryModeUsed set to “bsc”.

One of the adjacent cells is predefined as the one used for directed retry. The

adjacentCellUmbrellaRef parameter gives the position of this cell in the neighbor list.

CAUTION!

In this mode, there is no check of the RF conditions on the predefined target cell before the

directed retry HO occurs: the predefined cell must cover the whole area of the current cell.

To ensure that the MS is pre-synchronised with the predefined target cell (MS has decoded

GSM time and the BSIC), the neighbor cell BCCH must be put in the adjacentCellReselection

parameter bCCHFrequency.




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DIRECTED RETRY HANDOVER: BTS (OR DISTANT) MODE

This mode is enabled by the bts object parameter directedRetryModeUsed set to “bts”. It is

used, for example in the case of a high traffic cell covered by several neighbors.

When the BSC receives the Assign Request message from the MSC, the BSC requests the

BTS through a Connection State Request message to return a list of eligible neighbor cells

generated by the following criteria. This list is immediately sent through a Connection State

Acknowledgement message to the BSC. If the list is empty, the BTS tries to regenerate it later.

As soon as handover conditions are fulfilled for at least one neighbouring cell, the BTS sends

the BSC a spontaneous Handover Indication message with the specific cause “Directed

Retry”.

If RxLevNcell(n) > directedRetry(n) + Max[0, (msTxPwrMaxCell(n) - P)]

where P = maximum RF output power of the MS

then cell n is candidate for Directed Retry Handover

If RxLevNcell(m) = Max(RxLevNcell(n))

then Cell m is chosen by the BSC as the target cell for the Directed Retry HO

CAUTION!The Directed Retry criterion is based on only one measurement of RxLevNcell(n) and not on

NCellHreqave measurements.

In a microcell network, a directed retry HO may handover a call from a macro cell to a micro

cell even if the stability criteria is not fulfilled (microcellular handover type A). In this

environment, to avoid a ping-pong HO, one may put a high value to the adjacentCellHandOver

parameter directedRetryAlgo.

DIRECTED RETRY AND QUEUING

As soon as the directed retry is enabled in the BSS, whatever is the queuing activation, thedirected retry is processed. In that case,

• if queuing is activated, it is the same behavior as before V15.0. The only

change is that if the request could not be queued, the directed retry (if

allowed) is processed independently from the queuing.

• If queuing is desactivated, (or if the request could not be queued), then the

procedure is as follow: when the BSC receives from the MSC an Assignment

Request and there is no TCH available in the cell, then the directed retry

procedure is started and the BSC sends to the MSC a Queuing Indication

message to inform the MSC of a delay in the TCH allocation, and the MS

remains on SDCCH channel.




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If there is a resource in the target cell, the directed retry procedure is

successful and the communication is established.

If there is no resource available in the target cell, the directed retry

procedure fails and the BSS sends an Assignment failure (cause “no radio

resource available”) message to the MSC.If there is no neighbouring cells indicated by the BTS in the connection state

ack message, it means that neighbouring cells information are not available

in the BTS (it depends also on the MS performances) or handover conditions

are not met. Then the BSC starts an internal timer

directedRetryWithNoQueuingTimer (5 seconds, non configurable) in order to

wait for a handover indication message (cause “directed retry”) the BTS

sends if the handover conditions are fulfilled. The BSC processes this

handover indication message as described here above. In case the timer

directedRetryWithNoQueuingTimer expires, the BSC sends an Assignment

failure message (cause “no radio resource available”) to the MSC.

Note: during a directed retry procedure, if there is no TCH available in the target cell, the

procedure can neither be queued, nor execute another directed retry from the target cell.




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4.8.6 CONCENTRIC/DUALCOUPLING/DUALBAND CELL HANDOVER

CONCENTRIC CELL PRINCIPLES

The concept of concentric cell is enlarged and concentric cell parameter may have 4 possible

values: monozone, concentric, dualband or dualcoupling.

CONCENTRIC CELL

Definition: a cell is defined as concentric if it exists two transceiverzones configured to transmit

at different power resulting in two different coverage areas. For the two different

transceiverzones, the same antenna is used.

The principle of the concentric cells is to share the ressources in both zones assuming that the

TRXs are transmitting at different power. The BCCH and the signalling channels use the high

power TRXs (outer zone) thus the BTS needs to check if the link budget MS-BTS is sufficientto allocate a ressource of the inner zone. Furthermore, to avoid a subsequent intracell

handover, the BSC is checking this condition with the BTS each time a first TCH has to be

allocated at the end of the call setup, i.e an Assign Request has been sent by the MSC. The

same checking is done by the curent BTS when an intercell handover is required.

The smaller range of the frequencies in the internal zone, due to low maximum available

power for transmission, means that these internal zone frequencies can be reused a short

distance away. With this greater re-utilization of frequencies an operator can achieve the same

coverage using less bandwidth.

Concentric cell functionalities have been deployed allowing an easier frequency planning in

case of frequency hopping (fractional reuse techniques), and a major enhancement with the

TCH allocation directly in the relevant zone in case of calll setup and handover.

Note: a configuration with HePA on the outer zone and ePA on the inner zone is a kind of

concentric cell and not a kind of dualcoupling cell, eventhough the biZonePowerOffset

parameter has to be set accordingly to that particular case.

Please refer to the associated Functional Note [R10] Concentric cell improvements

(CM888/TF889). See also chapter Concentric Cells.

OuterzoneInnerzone

BCCH and

signalling

channels

traffic

channels

OuterzoneInnerzone

BCCH and

signalling

channels

traffic

channels




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DUALBAND CELL

Definition: a cell is defined as dualband if GSM900 TRXs and DCS1800 TRXs coexist and

share the same BCCH. The propagation loss being different, it results in two different

coverage areas.

Main benefits of dualband cell functionality are:

• The number of cells to configure and monitor is roughly divided by two

• No BCCH pattern has to be defined in the second band

• Frequency Hopping, Power Control, Downlink DTX are available on all second

band DRX’s (instead of all but one with conventional management)

• Slight increase in capacity: one TS saving + DCS and GSM DRX’s in one

pool, which provides more network control of the traffic distribution

• Intra cells Handover between DCS and GSM DRX’s of a same cell instead of

synchronous inter cell handovers reduce the muting time

Please refer to the associated Functional Note [R9] Dual band cells management:TF875. See

also chapter Concentric Cells.

DUALCOUPLING CELL

Definition: a cell is defined as dualcoupling if the TRXs are not combined with the same type of

combiner and thus have not the same coupling loss resulting in two different coverage areas.

In a dualcoupling cell, as the TRXs are not combined with the same type of combiner the most

powerful TRXs define the large zone. Such cells are managed with the concentric cell principle

and dualcoupling cell feature take advantage of it using different coupling modules rather than

a mono type coupling module in a sector.

Please refer to the associated Functional Note [R11] FN for stepped coupling. See also

chapter Concentric Cells.

Outerzone

band0GSM (or DCS)

Innerzone / band1DCS (or GSM)

BCCH and

signalling

channels

traffic channels

Outerzone

band0GSM (or DCS)


BCCH and

signalling

channels

traffic channels

OuterzoneH2D

InnerzoneH4D

BCCH andsignalling

channels

traffic

channels

OuterzoneH2D

InnerzoneH4D

BCCH andsignalling

channels

traffic

channels




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INTERZONE HANDOVERS FOR CONCENTRIC CELL / DUALCOUPLINGCELL

LARGE ZONE TO SMALL ZONE

The MS is permitted to migrate from the large zone to the small zone if:

• the MS is close to the BTS (Timing Advance used to estimate the MS to BTS

distance, only for concentric cells))

• and if RF conditions are good enough (RxLev downlink).

Note: The transceiverZone object parameter zone Tx power max reduction value is always set

to 0 for the large zone, and in the range of [1 to 55]dB for the small zone.

Since V18, a new criterion on uplink RxLev prevents MS from an assignment failure when the

uplink signal strength is not good enough to perform a handover toward the inner zoneThe Concentric/Dualcoupling Cell Handover from Large to Small zone is triggered if:

RxLev_DL > concentAlgoExtRxLev

AND

RxLev_UL>ConcentAlgoExtRxLevUL

AND (only for concentric cells)

MS_BS_Dist < concentAlgoExtMsRange

SMALL ZONE TO LARGE ZONE

The MS is handed over from the small zone to the large one if:

• the MS is far from the BTS (Timing Advance, used to estimate the MS to BTS

distance, only for concentric cells)

• or if RF conditions are too bad (RxLev downlink, RxQual uplink and downlink).




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For a non-AMR channel, or an AMR channel with legacy L1M, the Concentric/Dualcoupling

cell handover from small to large zone is triggered if:

RxLev_DL < concentAlgoIntRxLev

OR

RxLev_UL<concentAlgoIntRxLevUL

OR

RxQual_DL > lRxQualDLH

OR

RxQual_UL > lRxQualULH

OR

(only for concentric cells)

MS_BS_Dist > concentAlgoIntMsRange

For an AMR channel with AMR L1M, the Concentric/Dualcoupling cell handover from small to

large zone is triggered if:

RxLev_DL < concentAlgoIntRxLev

OR

RxLev_UL<concentAlgoIntRxLevUL

OR

(only for concentric cells)

MS_BS_Dist > concentAlgoIntMsRange

OR

Quality intercell HO on UL codec mode criterion is satisfied

OR

Quality intercell HO on DL codec mode criterion is satisfied

Please note that an external priority [0...17] can be given to the Concentric Cell Handover from

a Small to Large zone, because of the small to large Zone HO priority parameter.

INTERZONE HANDOVERS FOR DUALBAND CELLS

Convention:

• if BCCH gsm, then band 0 = gsm, band 1 = dcs and standardIndicator =

gsmdcs

• If BCCH dcs, then band 0 = dcs, band 1 = gsm and standardIndicator =

dcsgsm

The algorithms created for concentric cell are the same for dualband cells, except the timingadvance criterion is not used and the dualband capability of the mobile is checked.




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4.8.7 RESCUE HANDOVER

INTRACELL HANDOVER DECISION FOR SIGNAL QUALITY

The interferences are generally related to a specific TDMA. When signal quality is bad but

signal strength is sufficient, the BSC allocates another channel in the current cell.

Condition to be fulfilled is:

(((RXLEV_UL > rxLevULIH) AND (RXQUAL_UL > rxQualULIH))

OR

((RXLEV_DL > rxlevDLIH) AND (RXQUAL_DL > rxQualDLIH))

Thresholds should be set in order to ensure good subjective voice quality (rxqualXLIH 5 with

frequency hopping or rxqualXLIH 4 without hopping).

This feature is enabled by intraCell or intraCellSDCCH flags.

CAUTION!

In order to avoid the choice of a more interfered channel, channels are allocated in the 2 low

interference pools (hopping and not hopping); if no free channel is detected among these 2

pools and although queuing is allowed, the intracell HO must not be done; if queuing is

allowed, the request is queued then satisfied only after reception of suitable interference level

on idle channels (RF_RESOURCE_INDICATION message); when TDMA removals leads to

intracell HO, the first free resource is taken whatever its interference level.

Note: RF_RESOURCE_INDICATION message is received from BTS and induces the

interference level of channels of a particular TDMA. Therefore a channel has 3 states for the

BTS:

• Busy

• Free with interference measure level available

• Free without interference measure level available (for example the channel has just

been release and the measure are not yet done)

No interference level management is performed on PDTCH channels. The level status ofPDTCH resource is always high (bad level). So intracell HO is not performed on PDTCH




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4.8.8 POWER BUDGET HANDOVER

POWER BUDGET FORMULA

If powerBudgetInterCell parameter is set to “enabled” (handover on Power Budget is allowed),

the following formula is used to determine handover condition for power budget reason. This

handover is preventive and ensures best allocation of a serving cell for a given

communication. The formula used to determine handover condition for power budget reason

is:

EXP2PBGT(n) = Pbgt(n) - AdaptedHoMargin(n)

AdaptedHoMargin(n) is the margin computed when AHA feature is enabled. It takes into

account neighDisfavorOffset and servingfactorOffset parameters (see chapter Automatic

handover adaptation)

MINIMUM TIME BETWEEN HANDOVER

Minimun Time between handover feature is replaced by the General protection against HO

ping-pong feature.

However, in order for the new feature to be enabled the timeBetweenHOConfiguration

parameter must be set to “used”, and the bts Time Between HO configuration parameter must

be set to “1”.

4.8.9 HANDOVER FOR TRAFFIC REASONS

This feature aims at improving the network behaviour when one or several cells are

overloaded by attempting to redirect the most appropriate calls in progress to neighbour cells

with a PBGT handover procedure.

Please refer to the associated Functional Note [R12] Handover for traffic reasons: TF132. See

also chapter Handover for Traffic Reasons Activation Guideline.

This feature is enabled by the new BSC object parameter hoTraffic and by the new BTS object

parameter hoTraffic. For each neighboring cell of the cell (adjacentCellHandover object), a

parameter is defined: hoMarginTrafficOffset is the offset to (negatively) apply to the hoMargin

parameter linked to the power budget when the cell status becomes overloaded (if 0, the

handover for traffic reason is not allowed for this adjacent cell).

This features relies on the definition of the overload condition ; a cell overload condition can

only be determined by the radio resource allocator when the detection mechanism is

activated; it is activated as soon as the handover for traffic reasons feature or the Barring of

access class feature is authorized.




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This overload detection mechanism is based on the number of free TCH or the number of

queued TCH requests in the cell ; TCH resources reserved for maximum priority requests are

not taken into account ; in a concentric cell, TCH resources of the small zone are not taken

into account (no queuing procedure in the small zone) ; in a dualband cell, TCH resources of

the band1 are not taken into account (no queuing procedure in the band1) ; no more operator

warning is sent at the beginning and the end of the overload phase.

The overload begins when:

the number of free TCH <= numberOfTCHFreeBeforeCongestion

OR

the number of queued TCH requests >= numberOfTCHQueuedBeforeCongestion

The overload ends when:

the number of free TCH >= numberOfTCHFreeToEndCongestion

OR

the number of queued TCH requests <= numberOfTCHQueuedToEndCongestion

When the cell status becomes overloaded, a request is done to the L1M to consider a new

ho_margin (hoMargin-hoMarginTrafficOffset) ; this request is sent only to the TRXs which

belong to the large zone/band0 (for concentric/dualband cells).

In case of intra BSS handover (for traffic reasons), the BSC checks the target cell status

during the handover selection phase and if overload condition is set, the BSC will try on the

following cell of the list (a handover between the band0 of a serving cell and the band1 of a

target cell is possible if the eligibility of band1 is indicated in the handover indication

message).

In case of inter BSS handover (for traffic reasons), the target cell overload status is not known

until the HO procedure is launched (HO request). Also, a handover between the band0 of a

serving cell and the band1 of a target cell is not possible (due to the present A interface).

It is advised to set the General protection against HO ping-pong feature with this feature in

order to overcome the associated risk of ping-pong.

CAUTION!

This feature is not applicable for S4000/S2000E-DCU2 or S4000/S2000E-DCU2/DCU4.

This feature is applicable for all cases where PBGT handover is possible; so, handover for

traffic reasons is not possible between microcell and macrocell.

This feature is applicable to concentric/dualband cells but is restricted to the large zone/band0

since the thresholds used to define the overload conditions concern the large zone/band0 ; if a

handover indication is received by the BSC with a cause set to traffic reasons and concerns acommunication established in the small zone/band1 of the cell, the message is discarded.




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This feature is not applicable to a network which sets all the TCH request priorities to the

maximum priority since the cell is always overloaded whatever are the cell overload

thresholds.

Since the handover for traffic reasons feature uses the PBGT handover procedure, the

powerBudgetInterCell parameter shall be set to “true” (the BSC does not control this flag to

modify the hoMarginTrafficOffset). The BTS never transmits the Handover for traffic reasons if

this flag is not set.

There is no standby chain updating for the cell overload status ; thus, in case of switch-over,

the L1M value for hoMarginTrafficOffset is set to 0 and the cell is no longer overloaded.

About hoMarginTrafficOffset setting:

Typically, when hoMargin is reduced by 1dB (which implies that hoMarginTrafficOffset=1 dB),

this affects around 13% of the mobiles, assuming that cell overlapping is larger than the

hoMargin; roughly:

• 1dB of power reduction decreases the cell radius by 6.8% thus the cell

coverage by 13%

• 2dB of power reduction decreases the cell radius by 14%

• 3dB of power reduction decreases the cell radius by 21.9%

If hoMarginTrafficOffset is set to 0 dB, the HO traffic is somehow disabled since PBGT will be

done before the traffic has a chance to be done (higher priority).




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4.8.11 AUTOMATIC CELL TIERING

PREREQUISITE

It requires the implementation of L1mV2 and is exclusively applicable to fractional reuse

pattern networks (see chapter Frequency Hopping).

GOAL

The frequency tiering technique aims at decreasing the global interference level in a fractional

reuse pattern network and offers efficient traffic management at a TRX level through the self-

tuning system at the BTS

EXPECTED GAINS

The main benefits expected are:

• A large capacity increase: The cell tiering increases the fractional load

capabilities, therefore, permits bigger BTS configurations with the same

amount of available frequencies.). In a 1x1 network, the fractional load can go

up to 33.3% and up to 100% in 1x3.

• A better network quality (worst communications, typically at the cell boundary,

do no longer corrupt other communications). The reduction of the global level

of interference may also significantly decrease the global number of dropped

calls and other faults in particularly loaded networks.• A better uplink/downlink balancing (the uplink interference cancellation gain is

balanced by a significant downlink cell tiering improvement)

PRINCIPLES

The mechanism relies on simple dynamic resources allocation strategies that are intended to

allocate the worst communications, in terms of downlink Carrier on Interference ratio (CIR), to

the non-hopping frequencies (like BCCH), taking advantage of their larger reuse pattern and

consequently of their better resistance to interference, while the best communications are

driven to the hopping frequencies.

Evaluation of the calls is based on a ratio (in Watts) of the RxLevDL measured for the serving

cell over the sum of RxLevNCell measured for the BCCH of each neighbour, weighted

according to the type of interference brought (adjacent or co-channel).

This evaluation, called Potential Worst C/I (PWCI), potential because it does not include the

frequency hopping gain, is meant to simulate what the interference on the small pattern would

be like.




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The PWCI is computed by the BTS for all the calls in progress in the cell and arranged into an

averaged PWCI distribution that provides 2 handover decision parameters: lCirDLH (low) and

uCirDLH (high):

• lCirDLH is the abscissa corresponding to an ordinate of P% (percentage of

TCH resources in the large pattern) on the averaged PWCI distribution curve.

• uCirDLH is determined from: uCirDLH = lCirDLH + hoMarginTiering

In V12 P% is calculated as follow:

In V14, with AMR introduction P% is now calculated as follow:

• FH_HR% is the percent of HR calls managed by the hopping pattern in the

cell,

• HR% is the percent of HR calls managed in the cell.

The tiering handover decision can be summarised as:

• If PWCI > uCirDLH => HO is performed from large to small pattern

• If PWCI < lCirDLH => HO is performed from small to large pattern

The number of values required to trace the PWCI distribution curve may be modified via MMI

with the numberOfPwciSamples parameter (whereas cell tiering HO thresholds cannot be

tuned via MMI).

The lCirDLH is defined from the available traffic channels (i.e. TCH & PDTCH) in the non

hopping layer (because these one will be allocated to communications with worst PWCI). In

order to manage speech and data interworking, the averaged number of TCHs reserved for

data is defined with the nbLargeReuseDataChannels parameter.

To avoid the introduction of new configuration parameters or thresholds required by such a

function, the associated selfTuningObs functionality enables to set tiering working parameters

at their most relevant values, fitting with cell real radio profile and dynamically adapted to O&M

events or radio environment modifications ensuring that the gains of the tiering strategy are

always optimum.

P%=Number of non hopping TCH - nbLargeReuseDataChannel

Total number of TCH in the cell - nbLargeReuseDataChannelP%=

Number of non hopping TCH - nbLargeReuseDataChannel

Total number of TCH in the cell - nbLargeReuseDataChannel

P%=(Number of non hopping TCH – nbLargeReuseDataChannel) * (1 + Non_FH_HR%)

(Total number of TCH in the cell – nbLargeReuseDataChannel) * (1 + HR%)P%=

(Number of non hopping TCH – nbLargeReuseDataChannel) * (1 + Non_FH_HR%)

(Total number of TCH in the cell – nbLargeReuseDataChannel) * (1 + HR%)




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Formula of PWCI in Watts:

With

• RXLEV(0) the DL signal strength in Watts received from the serving cell, re-

scaled at maximum power (RxLev_DL + BS_Att)

• RXLEV (i) is the level in Watts measured on the BCCH of a neighbor cell

using the same TCH frequencies set as the current cell. These neighbors

generate co-channel interferences.

• RXLEV (j) is the level in Watts measured on the BCCH of a neighbor cell

using a TCH frequencies set different from that of the current cell. These

neighbors generate adjacent channel interferences.

• ADC corresponds to the first adjacent channel protection factor which is fixed

in the BTS software typically to 18dB

The PWCI value is the same whatever the effective load.

COMPATIBILITY WITH MULTIZONE CELLS

With concentric/dualband/dualcoupling cells, ACT is only applicable within the large zone.

Indeed, the tiering handover decision relies on the following algorithm:

• IF the TDMA bearing the considered channel belongs to the small pattern

AND does not belong to the small zone of a multizone cell:

IF pwCi < lCirDLH

THEN the channel will be put on the large pattern

• IF the TDMA bearing the considered channel belongs to the large pattern

(which implies that it belongs to the large zone):

IF pwCi > uCirDLH

THEN the channel will be put on the small pattern

PWCI=RxLevDL Watts

SUM [RXLevNCell (i)] Watts SUM [RXLevNCell (j) - ADC] WattsPWCI=

RxLevDL Watts

SUM [RXLevNCell (i)] Watts SUM [RXLevNCell (j) - ADC] Watts




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In this case, P is computed by considering exclusively the resources in the large zone

(hopping as well as non hopping). In order to perform a tiering handover, the communication

must be in the large zone and there must be fractional reuse in it. The large pattern will only

be the BCCH frequency (the other TRXs in the large zone must hop) and the communication

will stay in the Large zone.

CELL TIERING MONITORING

The PWCI statistics and uCirDLH/lCirDLH may be transmitted on the Abis interface according

to the selfTuningObs parameter; these statistics are available independently of the activation

of the feature.

The hoRequiredTch counter C1138 has 2 new screenings (tiering handover from large to

small pattern and tiering handover from small to large pattern) ; two new counters are added:

C1802 (hoSuccessTieringTch) and C1801 (hoFailureTieringTchNorr) with 2 screenings each

(0: large pattern to small pattern & 1: small pattern to large pattern).

The table below gives indicative values for the time required to gather nbPwCISamples

measurements for different cell configurations, assuming the average TCH occupancy rate is

75% and that one TCH provides 1 PwCI measurement every 480 ms which is roughly 2 PwCI

measurements per second:

Cell configuration 20000 nbPwCISamples 60000 nbPwCISamples

O2 (14 TCH) # 16 min # 48 min

O4 (29 TCH) # 8 min # 24 min

O8 (59 TCH) # 4 min # 12 minO16 (121 TCH) # 2 min # 6 min

The time required to reach a sufficient statistics as well as the time between two consecutive

tiering threshold updates depends on the number of samples required, and the capacity

(number of TCH) and load of the cell.

So a way to decrease the period between 2 consecutive threshold updates is about the half of

the time required to reach a first reliable statistics.

CAUTIONS

Because it takes advantage of BTS O&M centralization, this feature applies also to 2G

products (equipped exclusively with DRXs).

The activation of this feature implies a previous activation of the L1mV2.

The statistics (for PWCI) are not kept during upgrade and must be gathered again after the

site reconfiguration.

Intracell handover for quality and intracell tiering handover are exclusive (choice managed with

the intracell parameter of the handOverControl object). For mobiles at cells boundaries, if for

PBGT reasons, a handover is decided towards a new cell on a hopping TCH, a subsequent

handover for tiering reasons will be possible towards a non hopping TCH and so on, so




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inducing a risk of ping-pong handovers ; this drawback will be avoided with the well tuning of

hoMarginTiering parameter.

No tiering handover decision is possible if the TDMA bearing the current TCH belongs to the

small zone/band1 of a multizone/dualband cell.

If tiering is activated, no tiering decision is undertaken by the BTS as long as a reliable

statistics has not been gathered (minimum nbPwCISamples for PWCI measurements); field

experiments have shown that at least 20000 PWCI samples are needed.

In V12, statistics are not maintained on the BCF passive chain.

The cell tiering configuration relies on a correct definition of interferes for each cell (through

interfererType). This feature is based on values of PWCI that depend on the overlap, the

available spectrum and the sites' density but neither on the traffic nor the fractional load.

However, when the traffic is low, there are fewer samples than at the busy hour and the PWCI

distribution is therefore a touch less relevant.




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4.8.12 MICROCELLULAR HANDOVER

HANDOVER PECULIARITIES IN MICROCELL ENVIRONMENT

Microcellular algorithms were initially defined to avoid issues due to fast moving mobiles

connected to microcells. People thought that fast moving mobiles would not have enough time

to receive handover information coming from the network or would jump some microcells. To

avoid communication failures, specific handover algorithms were defined to send fast moving

mobiles to the macro layer.

However, experiments performed on several microcellular networks demonstrated that fast

moving mobiles linked to outdoor microcells do not present any issues. Microcellular

algorithms are used mainly to split traffic loads on the two layers, regardless of mobile speed.

Most microcellular algorithms are based on a “capture” threshold. Mobiles linked to amacrocell perform a handover towards the micro layer as soon as the field strength received

from a microcell is sufficiently high (whatever the field strength received from the macrocell)

for a sufficient duration.

The microcellular handover algorithm type A is also based on the stability of the signal. Before

V12, with L1mV1, the stability was checked on the best neighbouring microcell, now L1mV2

launches in parallel the confirmation process for the 6 best microcells.

MICROCELLULAR ALGO TYPE A

The following table describes permitted handover causes according to the type of the serving

cell and the neighbor cell.

Note: the traffic handover is only possible from a large zone (or monozone).

The capture handover algorithm can only be defined from a macrocell to a microcell. However

the type of a cell is defined relative to the type of the neighboring one. It means that the type of

a cell A can be a macrocell from the cell B point of view but can be a microcell from the cell C

point of view. This way, it is possible to use the capture handover algorithm on both sides,

macrocell to microcell and microcell to macrocell.

L1mV2: Selection of the 6 best microcells

MS stability check on these 6 microcells

Selection of the 6 new best microcells

(transmitted to BSC)

Handover execution

L1mV2: Selection of the 6 best microcells

MS stability check on these 6 microcells

Selection of the 6 new best microcells

(transmitted to BSC)

Handover execution




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Neighbour cell cellType [adjacentCellHandover]

normalType umbrellaType microType

normalType

signal quality

signal strength

distance

power budget

traffic

directedRetry (BTSmode)

forced handover

signal qualitysignal strength

distance

power budget

traffic

directedRetry (BTS mode)

forced handover

signal qualitysignal strength

distance

power budget

traffic


forced handover

umbrellaType

signal quality

signal strength

distance

power budget

trafficdirectedRetry (BTSmode)

forced handover

signal quality

signal strength

distance

power budget

traffic


forced handover

capture


forced handover

S e r v i n g c e l l c e l l T y p e

[ b t s ]

microType

signal quality

signal strength

distance

power budget

traffic

directedRetry (BTSmode)

forced handover

signal quality

signal strength

distance

directedRetry

(BTS mode)

forced handover

signal quality

signal strength

distance

power budget

traffic


forced handover

However the Type A handover algorithm has not been specifically defined to perform

handovers from microcells to the macrocell layer.

A timer linked to that algorithm is tunable via the microCellCaptureTimer parameter. That timer

prevents the BSC from doing a handover on capture reason during a fixed period.

See also General formulas for the capture expression:

EXP1Capture(n) = RxLevNCell(n) ave - rxLevMinCell(n)

Furthermore a strength level stability Criterion (microCellStability) has to be respected beforetriggering a handover toward the microcell.

While microCellCaptureTimer(n) goes on, if a normal handover decision is verified, a handover

towards a cell of the same type or a normal cell is allowed.

While a handover is decided, the list of eligible cells is provided at each runHandover

(microCellCaptureTimer (n) is not reinitialised).

The threshold microCellStability(n) must be put previously to 63 dB. This value ensures that a

handover is performed as long as the field strength received from the neighbor cell is higher

than the “capture” threshold. The value can then be reduced case by case.




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CAUTION!

The microcellular feature is an OMC-R option (must be activated at OMC-R installation).

Thanks to the Advanced Speech Call Items Evolution functionality (refer to [R30]) the range of

the microCellCaptureTimer has been modified.

Initially that modification was designed for GSM-R applications: microcellCaptureTimer at 500s

is to avoid to be captured by a railway station cell for a communication established in the train

and thus to avoid that an on going communication from a train arriving in a railway station with

no stop, is captured by the railway station cells and when leaving the railway station, leads to

a new handover to the railways track cells.

Before V15.1 microCellCaptureTimer, on adjacentCellHandover object, has a range [0 … 255]

which means a maximum of about 255 * runHandOver (runHandOver is expressed in

multiples of 480 ms for SACCH frames and multiples of 470 ms for SDCCH frames) for a

communication, before being captured by a neighbouring cell which has a minimum and a

stable rxlev during this period.The request consists in increasing the range of this parameter, so as it is kept as it is, but the

meaning of specific values are changed to give them greater values (conversion to a value

greater than 255).

microCellCaptureTimervalue received by the BTS

microCellCapture value used by the BTS for the computation

(number of reporting period x*480ms)

0 to 249 0 to 249

250 512 245 s

251 1024 491 s

252 2048 983 s

253 4096 1966 s

254 8192 3932 s

255 16384 7864 s

This table is applicable for a runHandOver = 1. If runHandOver = 2, then 491 seconds are

obtained with MicrocellCapture value set to 250.

Note: if the Handover on SDCCH feature is activated, the timer must be computed by

multiplying the BTS used value by 470 ms.




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4.8.13 FORCED HANDOVER

This feature is used to force a handover towards neighboring cells. If a cell is to be shut down,

forcing handovers avoids dropped calls.

It has to be used in addition to the soft blocking feature (barring of incoming Handover, barring

of new calls).

Through a Connection State Request message, the BSC requests that the BTS sends it a list

of eligible neighbor cells. This list, immediately sent through a Connection State

Acknowledgement message to the BSC, is generated by the following criteria:

EXP1Forced HO =(n) RxLevNCell(n) ave - [forced handover algo(n) + Max(0,


By putting a low value to forced handover algo(n) , the HO becomes easier: the cell is

released more rapidly.

CAUTION!

A forced HO is possible after a certain communication duration:

duration = Max( rxQualHreqave * rxQualHreqt, rxLevHreqave * rxLevHreqt,

rxNCellHreqave).

Therefore, when integrating this feature in the soft blocking procedure, the operating mode is

the following:

• soft blocking,

• wait a certain time (20 seconds),

• trigger the forced HO.

There is only one attempt per cell.

Another reason to use a Forced HO with soft blocking is that a Forced HO may interrupt a

Directed Retry HO (if the Connection State Request message of the Forced HO arrives before

the Handover Indication cause Directed Retry message). One must wait a period of time after

the soft blocking so that all calls have time to move from SDCCH channels to TCH channels.




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4.8.14 EARLY HANDOVER DECISION

PROBLEM DESCRIPTION

The time for a mobile to reselect a cell in idle mode is quite long. So, a mobile can start a

communication while camping in another cell, leading to a call drop in the worst case.

If the reselection algorithm execution occurs close to the border of cell A the mobile can setup

a call a short moment after in the cell B while the cell A is still selected. Unfortunately, the MS

has to wait a certain period of time before being able to make an handover. The system has to

perform some measurements before taking some handovers decisions.

This period of time is quite critical, there are some risks of call drop because of the low level ofthe signal.

Another issue is concerned by this feature ; that is the problem of a mobile turning at a street

corner, when the RxLev suddenly decreases in the serving cell and increases for a neighbour

cell.

FEATURE DESCRIPTION

The principle is not to speed the selection process but to allow a handover on PBGT quicker.

Time

Cell A

Cell B

1

2

3

Risk

of

call

drop

1 sel/reselection

algo execution

2 call setup in cell A

3 HO toward cell B

Time

Cell A

Cell B

1

2

3

Risk

of

call

drop

1 sel/reselection

algo execution

2 call setup in cell A

3 HO toward cell B

cell A

cell B

Beginningof new call

cell A actually selected

Endof last call

cell A

cell B

Beginningof new call

cell A actually selected

Endof last call




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Two shorter averages are defined for the level of the serving cell (rxLevHReqaveBeg) and for

the level of the neighbouring cells (rxLevNCellHReqaveBeg).

The L1M will use this new shorter averages at the beginning of the call until Max

(rxLevHreqave*rxLevHreqt, rxQualHreqave*rxQualHreqt) is reached and after loss and

recovery of BSIC.

The L1M must only wait:

• shorter level arithmetic average of serving cell (rxLevHReqaveBeg)

• shorter level average of the neighbouring cell (rxLevNCellHReqaveBeg)

Therefore, the handover can be performed more quickly and with less measurements.

The principle is not to speed the selection process but to allow a handover on PBGT quicker.

It allows to reduce the zone which represents the critical period of time. The first impact of this

feature is to reduce the probability of establishment failure and the call drop ratio.

A third parameter has been created (HOMarginBeg) in order to compensate the lack of

measurements by increasing the HOMargin.

The parameter rxLevNCellHReqaveBeg is used each time a new cell is detected by the

mobile. Therefore, it increases the system reactivity.

EXP2PBGT(n) early = Pbgt(n) - [hoMargin(n) + hoMarginBeg(n)]

UNTIL

Max(rxLevHreqave * rxLevHreqt, rxQualHreqave * rxQualHreqt) is reached

4.8.15 MAXIMUM RXLEV FOR POWER BUDGET

One of the issues to solve, in a microcellular network, is street corner (cross road)

environment:

In case of mobile moving straight the cross road (two orthogonal cells A and B), a handover

for Power Budget may be processed from cell B to cell A. Once the cross is passed, the

mobile is handed again over the cell B.

This ping-pong handover shall be avoided as useless handover leads to voice quality

degradation and signalling increase.

Another advantage of this feature is the possibility to reduce unnecessary handovers at border

of Location Area, interBSC or interMSC HO. In this case the need to perform Power Budget

handovers is diminished against the extra load on NSS and the voice quality.

The feature provides a solution by preventing handover for power budget from the serving cell

if the RXLEV downlink serving cell level exceed a specific threshold

To prevent handovers for power budget from the serving cell if the RXLEV downlink serving

cell level exceed a specific threshold (rxLevDLPBGT), the following expression used in

combination with existing cell selection criteria is actually:

RXLEV_DL < rxLevDLPBGT




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4.8.16 PRE-SYNCHRONIZED HO

During an asynchronous handover, the MS repeats the HO access bursts until it receives the

physical information message containing the timing advance of the new cell. So the speech

cut duration may last as long as the MS receives the new TA (Timing Advance) applied in the

new cell.

The pre-synchronized handover feature allows a Phase 2 MS to make a synchronized

handover between two (2) cells not belonging to the same site but managed by the same

BSC. The procedure is the same as for an intra-site synchronized handover, excepted that the

TA is set in advance and is transmitted to the MS at the beginning of the HO procedure.

CAUTION!

Only intra BSC synchronized handover are possible.

There are two possibilities to set the timing advance in case of pre-synchronized HO:

Presynchro with default value or with a determined Timing Advance.

Two parameters are impacted in the adjacentCellHandOver object to enable this feature:

• synchronized is set to the value “pre sync HO, with timing advance” or “pre sync

HO,default timing advance”.

• preSynchroTimingAdvance indicates the value of the TA.

By comparing not synchronized handovers with synchronized handover, a phonetic gain from

20ms to 40 ms is expected. This is due to the Physical_Info message suppression, which is

not necessary because on pre-synchronized handover, the timing advance value is carried by

the Handover_Command message. Moreover, only four Handover_Access messages are

used on pre-synchronized handover instead of more than four in case of not synchronized

handover.

4.8.17 RADIO CHANNEL ALLOCATION

The radio channel allocation is based on the interference levels computed on the BTS free

channels (SDCCH and TCH).

Every averagingPeriod the BTS sends RF RESOURCE INDICATION messages to the BSC.These messages are related to one TRX and contain the level of interference of the free

channels. These interference levels are classified into one from the five possible interference

bands (thresholdInterference parameter). In each of the five bands, the resources are sorted

from the least to the most recently used.

At the BSC level the free channels are divided into two new groups depending on whether

their interference level is above or below the RadChanSellIntThreshold value. Each group is

itself divided into two sub-groups, depending on whether the resource supports the Frequency

Hopping.




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CAUTION!

• If, during three (3) successive RF RESOURCE INDICATION messages, an

incoherency is noticed at the BSC level concerning the avaibility of a radio

channel, the channel is released and is returned free to the allocator.

• When a resource is released upon a call termination, it always returns to thepool of worst interference level, whatever its level before the allocation. The

next measurement received from the BTS for this resource will be used to

update the level and, consequently, to find the appropriate pool.

• The inner zone of a concentric cell does not support SDCCH channels. Till

V11, although they belong to the same cell, TCH pools for the inner zone are

separated from the same pools of the outer zone, and there are no possible

channel exchanges between the two zones.

• When a SDCCH is requested and no SDCCH is available, the external

priorities are considered as a TCH can be allocated instead of a SDCCH,

following the TCH allocation principles.

• If a TCH is requested and the priority threshold is reached, only priority 0

requests will be served. Other priorities will generate negative responses from

the allocator.

4.8.18 DEFINE ELIGIBLE NEIGHBOR CELLS FOR INTERCELLHANDOVER (EXCEPT DIRECTED RETRY)

When an intercell handover is required, the BTS sends a list of at most 6 best suitable cells

according to EXP1 and EXP2 formulas.

The following diagram shows an example of cell interlapping produced by different values of

lRxLevDLH (threshold out of Cell A) and rxLevMinCell (threshold in Cell B, assuming it is a 2W

mobile and msTXPwrMaxcell is set to 33dB). If values are too restrictive, then Cell B will not

be considered as an eligible cell for handover and the call might be dropped. This might be the

case especially in rural areas where cells have little overlap.

Putting a high value for rxLevMinCell(n) or a high value for msTXPwrMaxCell(n) results in

restricting access to that cell (see following diagram).

There is a different margin for each handover cause:

hoMarginDist, hoMarginRxLev, hoMarginRxQual (can be negative), hoMargin (for power

budget), thus compliance to that formula becomes mandatory i.e a handover can only be

performed towards a neigbourCell for which the (PBGT(n) - hoMargin(dist, rxqual, rxlev)) ispositive.

Cell BCell A

HO 1

-98 dBm

HO 2

-92 dBm

lRxLevDLH

-100 dBm

rxLevMinCell (B)

-95 dBm

Cell BCell A

HO 1

-98 dBm

HO 2

-92 dBm

lRxLevDLH

-100 dBm

rxLevMinCell (B)

-95 dBm




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4.8.19 HANDOVER TO 2ND BEST CANDIDATE WHEN RETURN TOOLD CHANNEL

This feature is triggered by a handover failure during the execution phase.

If hoSecondBestCellConfiguration = 1

then no HO attempt to 2nd best candidate cell


then HO attempt to 2nd best candidate cell


then HO attempt to 2nd best candidate cell and to 3rd best candidate cell

(if the HO attempt to 2nd best candidate cell fails)

When the HO attempt towards the last candidate fails, the bssMapTchoke starts at the BSC.

At the expiry of the timer, the BSC asks the BTS to provide a new list of eligible cells.

4.8.20 PROTECTION AGAINST RUNHANDOVER=1

The objective is to get a more responsive handover detection mechanism. To reach this goal,

the HO algorithm shall be run every 480 milliseconds (i.e runHandover =1 SACCH period).

This feature is useful for call drop rate improvement.

With this configuration (runHandover=1), a protection shall be implemented to avoid BSC

overload.

In case of saturated network (no free TCH) the request for handover (HO-Indication message)

will be repeated every 480 ms by the BTS, even if the target cell list has not changed.

This could cause SICD overload problems at the BSC. Although the BSC is protected against

this, such a situation should be avoided as much as possible in order not to disturb cells not

concerned by the congestion situation that could also be supported by the overloaded SICD.

As a consequence, the HO_Indication shall be repeated every 2 SACCH periods (1 second) in

case of run HO = 1.

If the content of the “preferred cell list” IE is modified (i.e. the content or the order of the cell

list), the HO_IND message shall be repeated every runHandover (even if runHandover=1).

In addition to that, the HO_IND message has also to be sent if the reason for handover has

changed, for the reason that there is no “preferred cell list” IE in case of intracell handover for

example.

The value of 1 second is justified by the fact that existing operational networks are currently

working with the value of runHandover=2, and therefore no strongest protection is needed.




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4.8.21 GENERAL PROTECTION AGAINST HO PING-PONG

This feature allows to easily solve some ping-pong handover problems (like ping-pong after

directed retry or ping-pong microcell -> macrocell -> microcell or ping-pongs already managed

by the previous feature Minimum time between Handover ).

It is enabled by the BSC object parameter timeBetweenHOConfiguration and by the BTS

object parameter bts Time Between HO configuration (0 means “not used” and value greater

than 0 means “used”).

For each neighboring cell of a cell (adjacentCellHandover object), two new parameters are

defined: hoPingpongCombination defines up to four combinations (incoming cause, outgoing

cause) used in order to define forbidden handovers during hoPingpongTimeRejection seconds

for all combinations.

When the BSC receives from the BTS a Handover Indication, it calculates the time spent in

the cell since the last handover (named connection_time) and removes from the preferred

cells list the eligible cells for which the connection_time is lower than the corresponding

timeRejection and for which the combination (incoming cause, outgoing cause) corresponds to

a combination defined in HOPingpongCombination.

The incoming causes may be: RXLEV (indifferently for uplink and downlink), RXQUAL

(indifferently for uplink and downlink), DISTANCE, PBGT, CAPTURE, DIRECTED_RETRY,

O&M (for forced handovers), TRAFFIC, AMRQUALITY, ALL (if the incoming cause matches

all the preceding causes), ALLCAPTURE, ALLPBGT.

The outgoing causes may be:

• RXLEV (indifferently for uplink and downlink)

• RXQUAL (indifferently for uplink and downlink)

• DISTANCE

• PBGT

• CAPTURE

• O&M (for forced handovers)

• TRAFFIC

• AMR QUALITY

• ALL (if the incoming cause matches all the preceding causes)

• ALLCAPTURE (if the outgoing cause matches the CAPTURE cause for all themicrocells belonging to the current macrocell)

• ALLPBGT (if the outgoing cause matches the PBGT cause for all the

neighboring cells of the current cell ; this cause can be used to restore the

“Minimum time between handovers” feature

AMR QUALITY cause has been introduced for AMR purpose. See also chapter General

protection against HO Ping Pong in the feature interworking part of AMR chapter.




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CAUTION!

The parameters hoPingpongCombination and hoPingpongTimeRejection must be defined at

the “entering cell” (relatively to the first HO of the combination) level, for the neighbouring cell

(adjacentCellHandover object) corresponding to the “left cell” (still relatively to the first HO of

the combination). Thus, these parameters are known by the “new BSC” whatever the type of

HO is (intra or interBSC).

For interBSS handovers, if the Cause element is not included in the HANDOVER_REQUEST

message sent from the MSC to the target BSC, then this feature is not applied except when

the incoming_cause in hoPingpongCombination parameter is set to ALL.

During upgrades, if bts Time Between HO configuration is greater than 0, then bts Time

Between HO configuration is set to 1, hoPingpongTimeRejection is set to the previous value of

bts Time Between HO configuration and hoPingpongCombination is set to (all, allPBGT) and if

bts Time Between HO configuration is equal to 0, then it keeps the same value,

hoPingpongTimeRejection is set to 0 and hoPingpongCombination is set to empty.

The C1166 counter related to the “Minimum time between handover” feature is removed and

replaced by the C1782 counter incremented when a cell is removed of the preferred cells list

(so, for one handover indication message, it can be incremented several times).

This feature gives no protection against intracell or interzone ping-pong handovers and gives

no protection against ping-pong handovers between more than 2 cells except for allCapture or

allPBGT outgoing causes.




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4.8.22 AUTOMATIC HANDOVER ADAPTATION

This feature adapts handover parameters to radio environment of each call, taking into

account mobile speed and frequency hopping. The objective is to minimize call drops and badquality transients.

PRINCIPLE

In order to eliminate the fading in the measurement processing, some averaging mechanisms

are implemented. But the frequency hopping and the mobile speed introduce frequency and

space diversity and average the attenuation of the received signal:

As shown on the diagram above, the faster the mobile moves the less the fading is impacting

(space diversity).

Mobiles can also be sensitive to the frequency diversity as shown on the diagram below. The

more hopping frequencies are used the less fading is impacting.




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The principle of this feature is to use these averages introduced by the frequency hopping and

the MS speed, in order to decrease the number of measurements take into account or the

handover margin.

DECISIONS FACTORS

FREQUENCY HOPPING

In order to have a sufficient averaging of the Rayleigh fading, the number of frequencies in the

hopping law has to be greater or equal than 4. If the number of frequencies in the hopping law

is less than 4, mobiles are considered as non-hopping, and all processing defined for non

hopping mobiles are applied.

This criterion and all associated mechanisms are applied to the following channels:

• TCH full rate whatever the channel coding (data circuit, EFR, FR, AMR…),

• TCH half rate,

• SDCCH.

MS SPEED EVALUATOR

From internal studies and simulation, a mobile can be considered as a fast mobile, if the

standard deviation in dB of the Rxlev during one period of measurement (i.e. 104 bursts, thus

480ms) is less than 1.4dB.

This standard deviation represents approximately:

• 20 km/h in GSM900,

• 10km/h in GSM1800 and GSM1900,

and is sufficient to have a good averaging of the Rayleigh fading.




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HALF RATE AND SDCCH CHANNELS

For half rate channels, the number of bursts during one period is sufficient to evaluate with a

correct accuracy the standard deviation criteria, then all treatments associated to this criteria

are relevant for this kind of channels.

UPLINK DTX

In case of uplink DTX activation during the period, the number of bursts received is decreased,

thus the accuracy of the calculated standard deviation is decreased. In this case, the standard

deviation is not evaluated and the last calculated standard deviation is taken.

UPLINK POWER CONTROL

In case of uplink power control, the BTS is not able to distinguish between a variation due to

Rayleigh fading and one due to a power control attenuation. Thus if the power control requireda variation of more than 8 dB during the period, then the standard deviation is not evaluated

and the last calculated standard deviation is taken.

AUTO ADAPTATION MECHANISMS

This feature is activated if the selfAdaptActivation parameter is set to “enabled”.

PBGT HANDOVER ADAPTATION

For this mechanism, two new parameters are added: servingfactorOffset, neighDisfavorOffset

and the previous factor hoMarginBeg is reused.

Following tables show for each case, the AdaptedHoMargin value and the averaging windows

taken into account in the PBGT handover mechanism according to

• the MS type: fast or slow mobile or managed by a hopping TCH,

• the number of measurement of the serving cell compared with the normal

averaging window,

• the number of measurement of the neighbouring cell compared with the

normal averaging window.

See chapter EXP2 to understand how AdaptedHoMargin is used.

For each cases of measurement, the tables below give the HO Margin result.

Example:

IF

number of available measurements for the cell < normal window

AND IF

number of available measurements for the neighbour cell < normal window

THEN

AdaptedHoMargin = hoMargin+ neighDisfavorOffset




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Mobile Type: SFH MS

cell measurement neighbour cell measurement AdaptedHoMargin

< rxLevHreqaveBeg < rxLevNCellHreqaveBeg hoMargin + neighDisfavorOffset

< rxLevHreqaveBeg ≥ rxNCellHreqave hoMargin

≥ rxLevHreqave < rxLevNCellHreqaveBeg hoMargin + neighDisfavorOffset - servingfactorOffset

≥ rxLevHreqave ≥ rxNCellHreqave hoMargin - servingfactorOffset

Mobile Type: Slow non SFH MS

cell measurement neighbour cell measurement AdaptedHoMargin

< rxLevHreqaveBeg < rxLevNCellHreqaveBeg hoMargin + hoMarginBeg

< rxLevHreqaveBeg ≥ rxNCellHreqave hoMargin + hoMarginBeg

≥rxLevHreqave < rxLevNCellHreqaveBeg hoMargin + neighDisfavorOffset

≥ rxLevHreqave ≥ rxNCellHreqave hoMargin

Mobile Type: Fast non SFH MS

cell measurement average neighbour cell average AdaptedHoMargin

rxLevHreqaveBeg rxLevNCellHreqaveBeg hoMargin

POWER CONTROL ADAPTATION

For this mechanism, a new parameter is added: rxQualAveBeg.

The following table shows for each case, the averaging taken into account in the power control

mechanism.

Mobile type RxLev average RxQual average

SFH MS rxLevHreqaveBeg rxQualAveBeg

“Fast” non SFH MS rxLevHreqaveBeg rxQualAveBeg

“Slow” non SFH MS no modification

In case of short averaging, due to the measurement quality, no specific value of K (refer to

chapter One shot power control (Pc_2) for more details on this value) is taken into account.

For slow mobile, Fast power control at TCH assignment (Pc_3) is still available in order to

reduce the power control activation time, but the first decision of power control is now taken

with Max[rxLevHreqAveBeg, rxQualAveBeg] measurements, instead of rxLevHreqAveBeg.

4.8.23 PROTECTION AGAINST INTRACELL HO PING-PONG

This feature controls the overall handover process, to avoid oscillations or so called "ping-

pong" handovers, to deal with the complexity introduced by all various situations with

BSC3000




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There are various reasons where intracell handovers needs to be triggered, for instance:

• RxQual degradation with high RxLev,

• transition from inner zone to outer zone in a multi-zone cell

but also

• transition from AMR-FR to AMR-HR,

• transition from outer zone to inner zone in a multi-zone cell.

The first two cases are required to maintain call quality, whereas the last two cases are

decided to optimise system capacity.

PRINCIPLE

For this feature, two kinds of intracell handover are distinguished:

• capacity intracell handover: this expression groups all intracell handovers,

which are triggered in order to increase the network capacity:

interzone handover from the outer to the inner zone,

AMR handover from FR to HR TCH,

tiering from BCCH to TCH frequency pattern.

• quality intracell handover: this expression groups all intracell handovers,

which are triggered if the quality of the call is not sufficient:

normal intracell handover,

inter-zone handover from the inner to the outer zone,

AMR handover from HR to FR TCH,

tiering from TCH to BCCH frequency pattern.

The principle of this feature is to introduce two timers, associated to the intracell handover

type, which delay an intracell handover after an intracell handover:

• capacityTimeRejection: defines the rejection time of a capacity intracell

handover after an intracell handover,

• minTimeQualityIntraCellHO: defines the rejection time of a quality intracell

handover after an intracell handover.

First intracell HO

minTimeQualityIntraCell HO

capacityTimeRejection

Quality intracell

HO request

Capacity intracell

HO requestFirst intracell HO

minTimeQualityIntraCell HO

capacityTimeRejection

Quality intracell

HO request

Capacity intracell

HO request




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4.8.24 GSM TO UMTS HANDOVER

PRINCIPLE

Thanks to this feature, GSM to UMTS handover is possible for dual-mode mobiles in areas of

2G-3G coverage.

This feature requires the setting of O&M parameters in the following domains :

• Normal or Enhanced Measurement Reporting activation and configuration

• UTRAN classmark activation and configuration

• Declaration of neighbouring cells belonging to the UTRAN

• Handover timers, thresholds and margins

PREREQUISITES

Note that EMR is not a preequisite for 2G-3G handover. The system can perform handover on

mobiles that perform normal reporting.

EARLY CLASSMARK SENDING ACTIVATION

Early classmark sending consists in the mobile sending as early as possible after access a

CLASSMARK CHANGE message to provide the network with additional classmark

information.

Early classmark sending activation is mandatory as EMR capability and FDD radio capability

is provided by the mobile to the BSS in the Classmark 3 IE sent in the CLASSMARK CHANGE

message.

Rule :

earlyClassmarkSending (v10 parameter) = allowed.

3G CLASSMARK SENDING ACTIVATION

Although it is not used by the BSS, the UTRAN classmark information is mandatory to perform

a GSM to UMTS handover as the "INTER RAT HANDOVER INFO" IE shall be included by theBSC in HANDOVER REQUIRED message.

The activation flag earlyClassmarkSendingUTRAN is used by the BSC and the MS:

• when the “3G Early Classmark Sending Restriction” field in SYSTEM INFORMATION

TYPE 3 message is set 1 (enabled), the MS is asked to the send its UTRAN

capabilites at the call set-up in the UTRAN CLASSMARK CHANGE message

subsequent to the CLASSMARK CHANGE one.




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• on an incoming handover, if the UTRAN capabilities have not been received by the

the target BSC in the HANDOVER REQUEST message, this BSC sends a

CLASSMARK ENQUIRY message in order to ask the MS to send the UTRAN

CLASSMARK CHANGE message.

Rule :

earlyClassmarkSendingUTRAN = ”enabled”.

USE OF MEASUREMENT INFORMATION MESSAGE

The MEASUREMENT INFORMATION message is used for 3 different purposes:

• declaration of UTRAN neighbouring cells and configuration of UTRAN reporting

requirements

• activation/deactivation of EMR feature

The feature GSM to UMTS handover can be used with either normal measurement reporting

or enhanced measurement reporting. The part of the MEASUREMENT INFORMATION

message related to EMR feature activation is fully described in §4.6.6.

When the mobile does not have the UMTS FDD RAT capability, it shall not receive information

about UTRAN cells. As a consequence, the BSC sends two different version of Measurement

information to the BTS: a 2G version with GSM cell information only and a 2G/3G version with

both GSM and UTRAN cell information. The BTS then broadcasts the appropriate message

according to each mobile’s capability and according to the status of the “GSM to UMTS

handover” activation, as specified in the table below.

GSM to UMTS HO disabled GSM to UMTS HO enabled

EMR disabled EMR enabled EMR disabled EMR enabled

Release 4 2G onlymobiles

No MI message MI 2G message None MI 2G message

2G-3G mobiles No MI message MI 2G message MI 2G-3G message MI 2G-3G message

The 2G measurement information message (2G MI) contains mainly the following information:

• reportTypeMeasurement : parameter that defines the type of measurement report that

the mobiles are required to use

• common (EMR and non-EMR) reporting configuration parameters :

multiBandReporting

• EMR-specific configuration parameters : servingBandReporting,


The 2G-3G measurement information message (2G-3G MI) contains mainly the following

information:

• reportTypeMeasurement : parameter that defines the type of measurement report thatthe mobiles are required to use




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• common (EMR and non-EMR) reporting configuration parameters :

multiBandReporting, qsearchC, fDDMultiRatReporting, fDDReportingThreshold2

• EMR-specific reporting configuration parameters : fDDReportingThreshold ,

servingBandReporting, servingBandReportingOffset

• UTRAN cells definition : mobileCountryCodeUTRAN, mobileNetworkCodeUTRAN,

locationAreaCodeUTRAN, rNCId, cId, fDDARFCN, scramblingCode, diversityUTRAN

NEIGHBOUR CELL LISTS

DEFINITION

The Neighbouring Cell List is built by a concatenation of two lists:

• The GSM Neighbour Cell List : it is the list of GSM cells, ordered by ARFCN and

BSIC, as defined in the BSIC_Description parameter of the

MEASUREMENT_INFORMATION message, which takes the first position in the list

• The 3G Neighbour Cell list: it is the list of UMTS cells, ordered by ARFCN &

scrambling code (the ARFCN are ordered the same way as received from the

network. For each ARFCN, scrambling codes are ordered in increasing number).

MAXIMUM SIZE

In this version the list is limited to 32 GSM cells and 32 UMTS cells.

When at least one UTRAN neighbouring cells is declared, only 31 different BCCH frequencies

for GSM neighbouring cells can be declared.

NEW BSS PARAMETERS

CREATION OF A NEW OBJECT

A new object is created alongside adjacentCellHandover: adjacentcellUTRAN.

2G-3G HANDOVER ACTIVATION : GSMTOUMTSSERVICE HO

PARAMETER

The following parameter (gsmToUMTSServiceHO) belonging to bsc object serves to

deactivate the 2G-3G Handover feature in all cells of the BSC or to provide a default GSM to

UMTS handover strategy when the MSC has failed to set one for the call :




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gsmToUMTSServiceHO value range :

• Shall not

• Should not

• Should

• GsmToUMTSDisabled

The MSC may include a similar “service handover” field in BSSMAP “ASSIGNMENT

REQUEST” and BSSMAP “HANDOVER REQUEST” messages sent to the BSS:

• Shall not: the BTS shall never hand off the communication to UTRAN (No UMTS

neighbouring cell can be present in the candidate cells list)

• Should not: the BTS shall not hand off the communication to UTRAN for a PBGT

reason but other criteria are nevertheless authorized to avoid call drop (handover for

alarm reason) or to reduce the load of the current cell when in congestion state

(handover for traffic reason)

• Should: It can be understood either as “immediate” or as “when possible or if

necessary”. The hoMarginUtran(n) parameter setting allows dual-mode MS to go

more or less easily on UTRAN layer. With a very negative values, the PBGT emulates

a capture in order to recover the UTRAN service as soon as possible.

For each call, we must differentiate the following cases :

• Case n°1 : gsmToUMTSServiceHO is set to GsmToUMTSDisabled.

Handover to UMTS is disabled.

• Case n°2 : "service handover" is provided by the MSC, and gsmToUMTSServiceHO

value is different from GsmToUMTSDisabled.

The MSC "service handover" value is sent to the BTS and the handover strategy is

decided by the MSC (according to OMC hoMarginXX setting).

• Case n°3 : "service handover" field is not provided by the MSC and

gsmToUMTSServiceHO is different from GsmToUMTSDisabled

Then, the default OMC "service handover" (i.e. the gsmToUMTSServiceHO

parameter) value is sent to the BTS and the handover strategy is decided by the

Access network instead of the Core network.

Note: In case the gsmToUMTSServiceHO is modified, the change only applies to new calls (or

after a handover) except for a feature deactivation.




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CONFIGURATION PARAMETERS OF CLASSMARK SENDING

The following parameter should be set to “enabled” to allow the mobile to send its UTRAN

Classmark at call setup :

• earlyClassmarkSendingUTRAN

The UTRAN_CLASSMARK_CHANGE message takes about 2 or 3 radio frames to transmit.

However, when supported by the UTRAN network, it is possible to reduce the size of the

message thanks to the compression of UE radio access capabilities and predefined

configuration Information Elements :

compressedModeUTRAN = enabled

Note: During IOT activities, it is recommended to disable this compression.

UMTS NEIGHBOUR CELLS DECLARATION PARAMETERS

The following 8 new parameters belonging to adjacentcellUTRAN object define the UMTS

neighbours :

• mobileCountryCodeUTRAN

• mobileNetworkCodeUTRAN

• locationAreaCodeUTRAN

• rNCId

• cId

• fDDARFCN

• scramblingCode

• diversityUTRAN

Up to 32 UMTS neighbours and 31 GSM neighbours may be declared.

MEASUREMENT REPORTING PARAMETERS

EMR must be activated for 2G-3G handover. The following 7 new parameters serve to

configure the Enhanced Measurement Reporting for 2G-3G handover purposes:

• reportTypeMeasurement

• qsearchC

• fDDMultiRatReporting

• fDDReportingThreshold

• fDDReportingThreshold2




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• servingBandReporting

• servingBandReportingOffset

2G-3G HANDOVER TIMER

t3121 has the same use as t3103 in the GSM inter-BSC handover procedure. It sets the value

before countdown of T3121 timer deined in the GSM specification:

• T3121 starts when the BSC sends an INTER SYSTEM TO UTRAN HANDOVER

message to the mobile.

• T3121 stops when the mobile has correctly seized the UTRAN channel. The purpose

of this timer is for the BSC to keep the old channels long enough for the mobile to be

able to return to the old channels.

• On expiry of T3121 (indicating the mobile is lost), the BSC may release the channels.

2G-3G HANDOVER THRESHOLDS

The following new parameters serve to configure thresholds :

• rxLevMinCellUTRAN

• rxLevDLPbgtUTRAN

These parameters have the same meaning as their counterparts on adjacentCellHandOver

object, but apply to a UTRAN neighbouring cell instead of a GSM neighbour cell.

2G-3G HANDOVER MARGINS

The following new parameters serve to configure margins for various types of handovers to 3G

cells :

• hoMarginUTRAN

• hoMarginAMRUTRAN

• hoMarginRxLevUTRAN

• hoMarginRxQualUTRAN

• hoMarginDistUTRAN

• hoMarginTrafficOffsetUTRAN

• offsetpriorityUTRAN

All these parameters have the same meaning as their counterpart on adjacentCellHandOver

object, but apply to a UTRAN neighbouring cell instead of a GSM neighbour cell.

In practice, all handovers algorithms except Capture and Directed retry are allowed towards

an UMTS neighbouring cell.

Note : the Power Budget handover as defined in GSM may be used to emulate a capture by

UTRAN layer.




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CONFIGURATION PARAMETERS OF PING-PONG MECHANISM FOR 2G-3G HANDOVERS

The existing mechanism to protect against ping-pong handover is used also for 2G-3G

handovers.

The list of outgoing causes for handovers towards UMTS neighbour cells is : traffic, pbgt,

rxLev, rxQual, dist, O&M (forced ho), all. This list is defined by setting the new parameter

hoPingpongCombinationUTRAN.

A specific timer is defined for time Rejection : hoPingpongTimeRejectionUTRAN .

If a pair of causes in the hoPingpongCombinationUTRAN parameter list refers to an incoming

or an outgoing cause that is not implemented in the source or in the target system, the existing

causes will be ignored.

On an incoming UMTS to GSM handover, if the BSC has not received the source "UTRAN

Cell identifier" (HANDOVER REQUIRED message / Old BSS to new BSS information"container / “Cell load information group” IE), no rejection timer will be started for that UTRAN

cell.

UMTS CELL LOAD MANAGEMENT

UMTS cell load management is managed three different ways:

• Through existing anti ping-pong mechanism for incoming 3G to 2G handovers

• Through a new mechanism for outgoing handover failures : When a UMTS cell rejects

the handover, the 2G-MSC sends a BSSMAP HANDOVER REQUIRED REJECT

message including cause “Traffic Load in the target cell higher than in the source cell”or “no radio resource available”. The BSC stores this information and does not attempt

a new handover towards this cell for a given time equal to

hoRejectionTimeOverloadUTRAN parameter.

• Through a new mechanism for incoming handover from UTRAN :

o if the handover cause in the BSSMAP HANDOVER REQUEST message is

either “traffic”, “directed retry” or “reduce load in serving cell” ,

o and if the source RNC and the MSC have implemented the “old BSS to new

BSS information” container

o and if the source RNC has included the “Cell load information group” withinthis container

o then the BSC stores the information and will not try a handover towards this

UTRAN cell for a given time equal to hoRejectionTimeOverloadUTRAN

parameter,

o otherwise, the BSC does not start any rejection timer for that UTRAN cell.




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SUMMARY OF HO 2G-3G PARAMETERS (V17)

Parameter name Definition object

cId Cell identity of the UMTS neighbouring cell for handoveradjacentCellUTRAN

compressedModeUTRAN

flag to indicate whether compressed mode UTRAN is supported ornot. This flag is used by the network to indicate to mobiles whether touse a compressed version of the INTER RAT HANDOVER INFOmessage (UE to UTRAN message).

bts

diversityUTRAN flag indicating whether there is deiversity in the neighbouring UTRANcell

adjacentCellUTRAN

earlyClassmarkSendingUTRAN flag indicating whether UTRAN classmark change message shall besent with Early Classmark Sending

bts

fDDARFCN fDD channel number of the UTRAN neighbouring celladjacentCellUTRAN

fDDMultiratReporting Number of FDD UTRAN cells to be reported in the list of strongestcells in the MR or EMR message

bts

fDDReportingThreshold (used in EMR only) defines the CPICH RSCP level above which theMS will apply a higher priority to UTRAN cells in the enhancedmeasurement report message

Handovercontrol

fDDReportingThreshold2 (used in MR and EMR) defines the CPICH Ec/N0 level above whichthe MS will report UTRAN cells in the normal or enhancedmeasurement report message

Handovercontrol

gSMToUMTSServiceHO This parameter serves to disable 2G-3G handover at BSC level or toindicate the preference (2G versus 3G cells) to be applied forhandovers

bsc

hoMarginUTRAN Handover margin for PBGT handover to a UMTS celladjacentCell

UTRAN

hoMarginAMRUTRAN Handover margin for intercell quality handovers to UMTS, for AMRcalls

adjacentCellUTRAN

hoMarginDistUTRAN handover margin for handover to UMTS on distance criterionadjacentCellUTRAN

hoMarginRxLevUTRAN handover margin for signal strength handover to UMTSadjacentCellUTRAN

hoMarginRxQualUTRAN handover margin for signal quality handover to UMTSadjacentCellUTRAN

hoMarginTrafficOffsetUTRAN offset to be subtracted to the homarginUTRAN to allow handover fortraffic reason when the current cell is congested

adjacentCellUTRAN

hoPingpongCombinationUTRAN list of pair of causes indicating the causes of ping-pong handovers inthe overlapping areas.

adjacentCellUTRAN

hoPingpongTimeRejectionUTRAN time that must elapse before attempting another handover towardsan UTRAN cell.

adjacentCellUTRAN

hoRejectionTimeOverloadUTRAN time that must elapse before attempting another handover towards acongested UTRAN cell

adjacentCellUTRAN

locationAreaCodeUTRAN Location area code of the UMTS neighbouring celladjacentCellUTRAN

mobileCountryCodeUTRAN Mobile country code of the UMTS neighbouring celladjacentCellUTRAN

mobileNetworkCodeUTRAN Mobile network code of the UMTS neighbouring celladjacentCellUTRAN

offsetPriorityUTRAN priority offset applied by the BSC when selecting the candidate cellfor the handover process

adjacentCellUTRAN




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Parameter name Definition object

qsearchC

search for UTRAN cells if signal level on the BCCH of serving cell :

is below threshold (0-7):

-98, -94, … , -74 dBm, ∞ (always)

or is above threshold (8-15):-78, -74, … , -54 dBm, ∞ (never)

If the serving BCCH frequency is not part of the BA(SACCH) list, andif the dedicated channel is not on the BCCH carrier, and if qsearchCis not equal to 15, the MS shall ignore the qsearchC parameter valueand always search for UTRAN cells. If qsearchC is equal to 15, theMS shall never search for UTRAN cells.

Handovercontrol

reportTypeMeasurement type of measurement report to be reported on this cell : enhancedmeasurement report or legacy measurement report

bts

rNCId identity of the UTRAN neighbouring cell’s RNCadjacentCellUTRAN

rxLevDLPbgtUTRAN downlink signal strength threshold above which handovers to UTRANfor cause power budget are inhibited

adjacentCellUTRAN

rxLevMinCellUTRAN minimum signal strength level that the MS must measure on anUMTS neighbour cell to be able to be granted a handover to thisUMTS neighbour cell

adjacentCellUTRAN

scramblingCode Scrambling code of the UMTS neighbouring celladjacentCellUTRAN

servingBandReporting defines the number of cells from the GSM serving frequency bandthat shall be included in the list of strongest cells in the measurementreport.

bts


If there is not enough space in the report for all valid cells, the cellsshall be reported that have the highest sum of the reported value(RXLEV) and the parameter servingBandReportingOffset(XXX_REPORTING_OFFSET) for the serving GSM band. Note thatthis parameter shall not affect the value itself of the reportedmeasurement.

Handovercontrol

t3121

t3121 has the same use as t3103 in the GSM inter-BSC handoverprocedure. It sets the value before countdown of T3121 timer definedin the GSM specification .

T3121 starts when the BSC sends an INTER SYSTEM TO UTRANHANDOVER message to the mobile. T3121 stops when the mobilehas correctly seized the UTRAN channel. The purpose of this timer isfor the BSC to keep the old channels long enough for the mobile tobe able to return to the old channels if necessary. On expiry of T3121(indicating the mobile is lost), the BSC may release the channels.

bts

2G-3G HANDOVER ALGORITHMS

REPORTING QUANTITY

In the Enhanced Measurement Report message, the downlink received power level of UMTS

neighbouring cells may be reported by the mobiles using one of two possible reporting

quantities :

• either CPICH RSCP

• or CPICH Ec/N0

In our v17.0 implementation, the reporting quantity that mobiles are expected to report to the

network is always CPICH RSCP. The mobiles are informed of this obligation by the

FDD_REP_QUANT flag that is sent by the network on SACCH in Measurement Information

messages.




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MAPPING BETWEEN RSCP (3G) AND RXLEV (2G)

This CPICH RSCP value is directly comparable to a “classical” RxLev value.

According to the mapping specified in the GSM specification, we can define the following

conversion table between RSCP values and the reported values in range [0..63]. Values below

0 are reported as 0 and values above 63 are reported as 63 by the mobiles. The L1M then

subtracts 5 to the reported value to obtain the equivalent Rxlev signal strength.

RSCP (unit : dBm) Reported value inside EMR(no unit)

L1M converted value (nounit)

RxLev “equivalent” in dBm

RSCP<-120 0 0 <-110

-120<RSCP<-119 0 0 <-110

-119<RSCP<-118 0 0 <-110

-118<RSCP<-117 0 0 <-110

-117<RSCP<-116 0 0 <-110

-116<RSCP<-115 0 0 <-110

-115<RSCP<-114 1 0 <-110

-114<RSCP<-113 2 0 <-110

-113<RSCP<-112 3 0 <-110

-112<RSCP<-111 4 0 <-110

-111<RSCP<-110 5 0 <-110

-110<RSCP<-109 6 1 -110<RxLev<-109

… … … …

-54<RSCP<-53 62 57 -54<RxLev<-53

-53<RSCP<-52 63 58 -53<RxLev<-52

-52<RSCP<-51 63 58 -53<RxLev<-52

… … … …

-26<RSCP<-25 63 58 -53<RxLev<-52

-25<RSCP 63 58 -53<RxLev<-52

ALGORITHMS

Once the power level of all 2G and 3G neighbouring cells can be compared with one another,

all L1M handover algorithms are directly reusable.

For example, the algorithm for a Power Budget handover to UTRAN can be described as

follows :

• The MS listens to UTRAN cells if RxLev < qsearchC

• The MS reports the measured RSCP of the UTRAN cells for which CPICH Ec/N0 ≥

fDDReportingThreshold2

• The “service handover” shall be set to “should”

• The BTS discards UTRAN cells for which :

o either CPICH RSCP < rxLevMinCellUTRAN(n)

o or RxLev of the serving cell > rxlevDLPbgtUTRAN(n)

• PBGT handover decision is taken if :




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o CPICH RSCP(neighbour 3G cell) > RxLev (serving 2G cell) +

hoMarginUtran(neighbour 3G cell).

• UTRAN cells are sorted according to EXP2() values

IMPACT OF HO 2G-3G ON INTERFERENCE MATRIX

UMTS cells are not measured by the Interference Matrix feature.

EMR CASE

The introduction of UTRAN neighbouring cells has an impact on Interference Matrix feature

because of the number of GSM neighbour cells it induces.

If at least one UTRAN neighbour cell is declared, no more than 31 GSM neighbour cells can

be declared, instead of 32. The impacts on IM are the following:

• The algorithm that calculates the number of cycles (used by launching tool on OMC-R

and by BSC for cycle definition) shall be done with only 31 BCCH frequencies

• UTRAN neighbour cell creation must be forbidden if 32 different BCCH frequencies

are already declared for GSM neighbour cells

• GSM neighbour cell creation with a 32nd different BCCH frequency must be forbidden

if at least one UTRAN neighbour cell is declared.

• UTRAN neighbour cell creation, UTRAN neighbour cell deletion, fDDARFCN change,

scramblingCode change, must be forbidden while Interference Matrix feature isrunning on the BSC.

• the control that warns the operator if he tries to activate Interference matrix when one

cell has 32 GSM neighbouring cells (this control exists already in this case) must be

extended to the case where one cell has 31 GSM neighbouring cells and at least one

UTRAN neighbouring cell.

NORMAL MR CASE

Although fewer possibilities are available with MR than with EMR, the way GSM and UTRAN

neighbouring cells are reported in Measurement report messages is manageable, thanks to

multiBandReporting and fDDMultiratReporting parameters. Unlike EMR, the number of

reported non-serving band GSM and UTRAN valid neighbouring cells has an impact on the

number of remaining spare places in the Measurement report message that could be used for

fake neighbours in Interference Matrix.




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4.9. HANDOVER ALGORITHMS ON THE MOBILE SIDE

For an intracell handover, the mobile receives an ASSIGNMENT COMMAND and simply

switches to another timeslot belonging to any TDMA of the cell.

For an intercell handover, upon reception of the HANDOVER COMMAND, the mobile checks

if it has the synchronization information. If not a handover failure is reported and

communication remains on old channel.

Then, if it is a synchronized handover, four access bursts are sent on the new channel before

actually switching to it.

If it is a non synchronized handover, the mobile will send contiguous access bursts on new

cell, expecting a PHYSICAL INFORMATION message to be sent back by the BTS, in order to

know the Timing Advance to be used on the new channel and actually switch to it. If that

message is not received within one second, then there is a handover failure and the mobile

returns to the old channel.

Once on the new cell, the mobile tries to establish level 2 connexion (SABM and UA exchange

procedure). If that procedure fails, then the mobile returns to the old channel, but if it succeeds

the synchronization information with previous best cells is kept for updating with new cell

parameters.

To conclude this paragraph, one realizes that a handover can be a rather lengthy process,

which should not be performed too late in order to ensure its success and not too often to

maintain a smooth voice or data flow.




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4.10. POWER CONTROL ALGORITHMS

The aim of the Power Control feature is to reduce the average interference level on the

Network and to save mobile batteries.

4.10.1 STEP BY STEP POWER CONTROL

CAUTION!

In L1mV2, RxLevXX is always rescaled at the maximum power output (see chapter

Measurement Processing)

This algorithm is a step by step full path loss compensation. The algorithm determines the gap

between the received level at Pmax (theoretical maximum power without taking into account

Power Control) and the power control threshold (lRxLevDLP, lRxLevULP) and compensates

the path loss step by step until the received level reaches the threshold. That algorithm has

been improved in L1mV2 with the introduction of a limitation based on the one shot

computation when there is a need to re-compute the attenuation (high level and good quality)

The basic idea of the step by step power control algorithm is:

• to reduce transmitted power when reception level is high and quality is

good

• to compute a new transmitted power with total path loss compensation

when reception level is high and quality is good

At every runPwrControl event, the Weighted Average is computed at Pmax (SAveRxlev) and

the following algorithm is perfomed by Ms/Bs:

IF (SAveRxLev < lRxLevP) OR (SAveRxQual > lRxQualP)

NewAttRequestdB = Max (CurrentAttRequestdB - IncStepSizeXX, 0)

ELSE IF [(SAveRxLev > uRxLevP) AND (SAveRxQual < uRxQualP)]

TempAttRequestdB = SAveRxLev – lRxLevP

IF (TempAttRequestdB < CurrentAttRequest –IncrStepSizeXX)

NewAttRequestdB = CurrentAttRequestdB – IncStepSizeXX

ELSE IF (TempAttRequestdB > CurrentAttRequest + RedStepSizeXX)

NewAttRequestdB = CurrentAttRequestdB + RedStepSizeXX

ELSE NewAttRequestdB = TempAttRequestdB

ELSE ((lRxLevP ≤SAveRxLev ≤ uRxLevP) OR (uRxQualP ≤ SAveRxQual ≤ lRxQualP))

NewAttRequestdB = LastCommandedAttRequestdB

The resultfor the new attenuation request is stored into NewAttRequestdB




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The figure below summarizes the command for (UL or DL) transmission power according to

RxLev/RxQual values.

CAUTION!

When the MS or the BTS is in the “NEW TX POWER COMPUTATION” zone, the re-

computation of the attenuation does not lead necessarily to a reduction of the emitted power.

Note: This feature is activated at the BTS level by setting the following parameters:

• powerControl object: uplinkPowerControl = enabled and bsPowerControl =

enabled

• bts object: new power control algorithm = step by step

4.10.2 ONE SHOT POWER CONTROL

CAUTION!


Measurement Processing).

The enhanced power control is a one shot partial path loss compensation algorithm.

The one shot power control algorithm determines the “optimal” transmit power by computing a

partial path loss compensation and compensates it in one step.

This feature is activated at the BTS level by setting the following parameters:


enabled

• BTS object: new power control algorithm = one shot

RxQual

lRxQual

uRxQual

RxLevlRxLev uRxLev

Increase Tx Power

No new command for MS

(or BS) transmission power

New Tx Power computation

RxQual

lRxQual

uRxQual

RxLevlRxLev uRxLev

Increase Tx Power

No new command for MS

(or BS) transmission power

New Tx Power computation




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At every runPwrControl event, the Weighted Average is computed at Pmax (SAveRxlev) and

the following algorithm is perfomed by Ms/Bs:

IF (SAveRxLev < lRxLevP) OR (SAveRxQual > lRxQualP)

NewAttRequestdB = 0

ELSE

NewAttRequestdB = K * (SaveRxLev - lRxLevP)

The values of K depend on the activation of frequency hopping and of the RxQual. Here are

the values of K, which come from simulation results:

RXQUAL 0 1 2 3 4 5 6 7

K with Frequency Hopping 0,9 0,8 0,7

K without Frequency Hopping 0,7 0,6 0,5

The figure below summarizes the command for (UL or DL) transmission power according to

RxLev/RxQual values.

Please note that if NewAttRequestdB = 0 then the MS power becomes equal to the maximum

power possible in the cell, i.e. Min(msTXPwrMaxCell(n), MSTxPwrMax). The limitation can

come from the mobile (MSTxPwrMax) or from the cell (msTxPwrMax).

Concerning the BTS, the attenuation (difference between current power and max power) is

considered, so if NewAttRequestdB = 0 then the BTS power becomes equal to the maximum

static power possible.

RxQual

lRxQual

RxLevlRxLev

Tx Power max

(MS or BS attenuation = 0)

New Tx Power

computation

RxQual

lRxQual

RxLevlRxLev

Tx Power max

(MS or BS attenuation = 0)

New Tx Power

computation




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CAUTION!

An 8 dB limitation applies on decrease, e.g.the BTS will never decrease its power by more

than 8 dB (some mobiles would lose the BTS)

4.10.3 FAST POWER CONTROL AT TCH ASSIGNMENT

CAUTION!


Measurement Processing).

This feature is an improvement of the one shot power control (described above). One shot

power control reactivity is improved by deciding power control on SDCCH allocation and on

TCH allocation with only rxLevHreqaveBeg or rxQualAveBeg measurements. With this

feature, attenuation (possibly decided on SDCCH) is kept at TCH assignment and for each

channel switch-over (start on SDCCH, SDCCH to TCH or TCH to TCH), the few first

measurements (from Max[rxLevHreqAveBeg, rxQualAveBeg] to Max[rxLevHreqave *

rxLevHreqt, rxQualHreqave * rxQualHreqt]-1) may be used to decide power control.

This feature is activated by setting the following parameters:


enabled

• BTS object: new power control algorithm = enhanced one shot

The triggering of the one shot power control is accelerated because rxLevHreqaveBeg or

rxQualAveBeg measurements are taken into account.

Until Max[rxLevHreqave * rxLevHreqt, rxQualHreqave * rxQualHreqt] is reached, theattenuaton is computed with the compensation factor K for uplink and downlink. This factor no

more depends on the rxQualHreqave measurements but only on the frequency activation:

NewAttRequestdB = K * (SaveRxLev - lRxLevP)

• K = 0.5 in case of non hopping channel,

• K = 0.7 in case of hopping channel,

When Max[rxLevHreqAveBeg, rxQualAveBeg] > Max[rxLevHreqave * rxLevHreqt,

rxQualHreqave * rxQualHreqt] this feature is no more activated.

When Max[rxLevHreqave * rxLevHreqt, rxQualHreqave * rxQualHreqt] is reached the usual

average of the one shot power control described before is computed with the K value

depending of the rxQualHreqave measurements.

CAUTION!

This feature is not supported with DCU2 boards or with a mix of DCU2/DCU4 boards.

Note: In some very specific cases with a poor quality and a good level strength (very interfered

environment) the Fast Power Control algorithm may prevent from powering up after a TCH

assignment until max(rxLevHreqave*rxLevHreqt, rxQualHreqave*rxQualHreqt) is reached.




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4.10.4 POWER CONTROL ON MOBILE SIDE

In RACH phase, the MS power is equal to Min [msTxPwrMax, msTxPwrMaxCCH].

When the MS switches from RACH to SDCCH or TCH, it keeps the same power.

In dedicated mode, the mobile transmits at the power required in the POWER COMMAND

message transmitted in the layer1 header of SACCH blocks. This command will be received at

the end of a reporting period (102 frames in SDCCH, 104 in TCH). It will be applied at the

beginning of the following period at a rate of 2dB per 13 frames.

Before triggering an intercell handover due to uplink causes (RXQUAL or RXLEV) and only

step by step power control and for L1mV1 (only), the BTS should request the MS to transmit to

its maximum power capability. In such cases, if the MS can increase its transmit power, no

Handover Indication is transmitted by the BTS.

In the case of a handover, the maximum transmitted power allowed in the target cell is sent tothe mobile in the handover command message (msTxPwrMaxCell).

In case of intracell handover, the power reduction is kept.

The current txpwr value is saved so that it can be sent in the next transmitted uplink SACCH.

For the BTS, the duration of the entire process (from order to acknowledgment) is three

multiframes.

4.10.5 AMR POWER CONTROL

With the introduction of the AMR feature a new Layer 1 Management has been desgined to

take into account AMR channels specificity, including new algorithm for Power Control.

Please refer to section Power Control in the chapter AMR - Adaptative Multi Rate FR/HR.

SA0 SA1 SA2 SA3 SA0 SA1 SA2 SA3 SA0 SA1 SA2 SA3

BTS sends PC andTA

commands in a

SACCH block

MS gets the

SACCH block

MS starts applying

New PC and TA

One SACCH reporting period

26 * 4 = 104 frames (480 ms)

MS starts transmitting

SACCH concerning

Previous multiframe

BTS gets the

Measurement

Report

SA0 SA1 SA2 SA3 SA0 SA1 SA2 SA3 SA0 SA1 SA2 SA3

BTS sends PC andTA

commands in a

SACCH block

MS gets the

SACCH block

MS starts applying

New PC and TA

One SACCH reporting period

26 * 4 = 104 frames (480 ms)

MS starts transmitting

SACCH concerning

Previous multiframe

BTS gets the

Measurement

Report




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4.10.6 POWER ADAPTATION AFTER AN INTERZONE HO

This section is only applicable to RF power control in multizone cells (see

Concentric/DualCoupling/DualBand Cell Handover ).

PURPOSE

Before V17.0, after an inter-zone handover, the BSC sets the BTS and MS initial powers on

the new channel of the new zone to values that are identical to those used on the previous

channel in the other zone. As a result, the strength of the uplink and the downlink received

signal may decrease significantly on the establishment on the new channel. The risk is that the

handover could fail or the voice quality could deteriorate until the BTS has adjusted the BTS

and MS output TX power on the first run of the L1M power control process.

In v17.0, if the BSC expects the reception level to decrease following the interzone handover,

the BSC shall adapt the BTS and the MS output power, when activating the new channel, toensure a constant reception level for the MS and for the BTS. If on trhen other hand, the BSC

expects the reception level to increase, the BSC shall keep the BTS and MS power levels

unchanged and will simply wait for the L1M to adjust them via the standard power control

process.

ESTIMATION OF THE THEORETICAL POWER GAP

The BSC has to estimate the power gap in uplink and in downlink that would exist after an

inner to outer zone handover and an outer to inner handover :

• Delta_RxLev_DL_oz_to_iz : DL signal strength gap following an outer to inner HO

• Delta_RxLev_UL_oz_to_iz : UL signal strength gap following an outer to inner HO

• Delta_RxLev_DL_iz_to_oz : DL signal strength gap following an inner to outer HO

• Delta_RxLev_UL_iz_to_oz : UL signal strength gap following an inner to outer HO

This estimation depends only on the following O&M parameters :

• concentric_cell (bts object): parameter defining the type of multizone cell : concentric,

dualband or dualcoupling.

• zoneTxPowerMaxreduction (transceiverZone object): attenuation to be applied to

bsTxPwrMax (maximum theoretical level of BTS transmission power in a cell),

defining the maximum TRX/DRX transmission power in the zone.

• bizonePowerOffset (handoverControl object): Estimated downlink power offset

between inner zone and outer zone TRXs of a multizone cell. For a dual-band cell,

this parameter has to be estimated in a worst case (edge of band1 zone). For a

concentric or dualcoupling cell, bizonePowerOffset = zoneTxPowerMaxreduction

The 3 different cases of concentric cell give different resultrs for the power gap :




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Concentric Dual-coupling Dual-band

Delta_RxLev_DL_ oz_to_iz

ZoneTxPowerMaxReduction [oz]- ZoneTxPowerMaxReduction [iz]

ZoneTxPowerMaxReduction [oz]- ZoneTxPowerMaxReduction [iz]

ZoneTxPowerMaxReduction [oz]- ZoneTxPowerMaxReduction [iz] - bizonePowerOffset (

3)(

4)

Delta_RxLev_UL_

oz_to_iz

0(1) 0(

1) - bizonePowerOffset (

3)

Delta_RxLev_DL_ iz_to_oz(

5)

-(Delta_RxLev_DL_oz_to_iz) -(Delta_RxLev_DL_oz_to_iz) -(Delta_RxLev_DL_oz_to_iz)

Delta_RxLev_UL_ iz_to_oz(

5)

0(1) 0(

1) bizonePowerOffset

Notes :

(1) : for concentric and dualcoupling cells, there is no uplink signal strength gap. The uplink

gap only applies to dualband cells.

(2) : the type of coupler (D, H2D etc) does not impact the formula because the BTS takes the

coupling into account to reach the required output power which is equal to bstxpwrmax -zonetxpowermaxreduction. So it is the same formula as concetric cell.

(3) : The higher the frequency, the steeper the signal strength decrease as a function of MS-

BTS distance. “bizonePowerOffset” is a worst case assessment of this path loss performed at

the inner-zone boundary.

(4) : As both heterogeneous coupling and dual-band could be applied simultaneously to a cell,

zoneTxPwrMaxReduction must be taken into account in te downlink formula

(5) : We hold this truth to be self-evident, that the inner-to-outer zone power gap is the

opposite of the outer-to-inner zone power gap.

CORRECTION OF THE POWER GAP

Upon activating the channel in the destination zone, the BSC considers the relevant

theoretical power gap as well as the last BTS transmission power and MS transmission power

used on the channel of the initial zone. These are reported by the BTS to the BSC in the Abis

connection state ack message.

MS TRANSMISSION POWER ADAPTATION

As explained above, no power adaptation is required on the uplink for a Concentric cell or a

Dual-coupling cell.

In a Dual-band cell :

• if the uplink power gap is less than zero, this power loss shall be corrected with a

command sent to the MS to increase its transmission power

• if the uplink power gap is more than zero, the last MS transmission power level shall

be kept unchanged. However, the new MS transmission power level shall not be

allowed to exceed the maximum power allowed by the network and the maximum MS

output power allowed in that band.




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4.11. TCH ALLOCATION MANAGEMENT

4.11.1 TCH ALLOCATION AND PRIORITY

ALLOCATION AND PRIORITY (RUN BY THE BSC) (ALL_1)

Different priorities are defined in GSM to prioritise TCH resource usage for the different types

of procedures. Basically, GSM procedures can be divided into the following types:

• Assignment Request Messages: coming from MSC. It includes Public calls

and WPS calls. The only difference between the types of Assignment

Requests is basically the priority included in the message.

• InterBSC Handovers

• IntraBSC Intercell Handovers

• Directed Retry Handovers

• IntraCell Handovers: normal Intracell HO, small to Large zone, AMR, cell

tiering …

• TCH overflow cases: this includes different procedures in the signaling phase

when trying to get a resource SDCCH. If this one is not available, a resource

TCH will be requested instead.

For certain procedures like the handovers, where reactivity is crucial, it is important to

immediately have TCH resources available. This can be done by reserving some resources for

them. For other procedures like the Assignment Requests where the communication is not

established yet, it might be more interesting to allow the queuing of the requests for someseconds in order to gain access to the network even if it is a few seconds later. The reactivity

time in this last context is not as important as for the handovers. To be able to control this, a

priority system has been created.

Priorities can be divided into two different groups: external and internal. The BSC is in charge

of converting external priorities into internal ones. Conversion rules will be detailed.

Two kinds of external priorities, NSS external priorities and BSS external, can be defined:

• NSS external priorities are those included in the BSSMAP message coming

from the MSC. As only the Assignment Requests and the Handover Requests

(for interBSC HO) can generate this type of messages, these are the onlyprocedures having an external NSS priority.

• BSS external priorities are defined via OMC parameter settings. They are set

for all types of procedures, even for the Assignment Requests.

The type of external priority of the Assignment Request procedures taken for conversion to an

internal priority is depending on the value of another OMC parameter (bscQueuingOption) that

indicates if the mode is “MSC driven” or “OMC driven”.

The mode “MSC driven” means that it is the NSS external priority which is taken into account

for internal priority conversion of Assignment Request Procedures. For Handover Request and

TCH overflow, it is BSS external priority that is used for conversion.

The mode “OMC driven” means it is the BSS external priority which is taken into account for

conversion, whatever the procedure.




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CAUTION!

Note that if we are in “MSC driven” mode there might be different Assignment Requests

coming from MSC with different priorities, meaning that we could treat them differently

according to the type of call.

However, in “OMC driven” mode there is only one priority, set with a parameter, for all the

types of Assignment Requests. In particular, assignment requests with cause emergency call

are not differentiated from the other assignment requests.

At this point we can start introducing some of the main OMC parameters used for the TCH

allocation management:

ALLOCATION AND PRIORITY PARAMETERS

bscQueuingOption

bscQueuingOption = allowed bscQueuingOption = forced bscQueuingOption = not allowed

MSC driven mode

Queuing is allowed

NSS external priorities are takeninto account for AssignmentRequest.

BSS external priorities are takeninto account for handover requestand TCH overflow

OMC driven mode

Queuing is allowed

BSS external priorities aretaken into account for allprocedures

OMC driven mode

Queuing is not allowed

BSS external priorities are taken intoaccount all procedures.

allocPriorityTable

It is probably the most important parameter for the allocation priority management. It is used to

make the conversion between external and internal priorities and it consists of a vector

containing 18 values. The values can go from 0 to 12 and define the internal priorities

associated to the different procedures. The association between external and internal priority

is done using the index number (or slot number) in this table that goes from 0 to 17. The index

in the table represents the BSS external priority. When NSS external priority is used, in order

to convert into internal priority, we look in the slot NSS external priority - 1.

NSS external priority contained in the BSSMAP message can take a value from 1 to 14. Slots

1 to 5 are reserved for WPS call treatment.Example: allocPriorityTable = 0 8 9 10 11 12 2 2 2 2 2 2 2 2 3 0 4 2

Slot number 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

allocPriorityTable 0 8 9 10 11 12 2 2 2 2 2 2 2 2 3 0 4 2

With this example in MSC driven mode, for a BSS external priority = 16, the internal priority

defined is 4 and for a NSS external priority = 5, we have to look at the slot number = 5 – 1 = 4,

so the internal priority is 11.




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Interest of MSC driven mode is to allow distinction between assignment request and then the

possibility to set different priority for them (WPS calls, VIP users …).

CAUTION!

if WPS is activated, Slots from 1 to 5 are reserved for WPS priorities, as the assignmentrequest coming from the MSC for WPS requests can go from 2 to 6 (see chapter WPS -

Wireless Priority Service).

QUEUING DRIVEN BY THE BSC (ALL_3)

The OMC drive mode is enabled by the bscQueuingOption parameter set to “forced”.

In this mode queuing is used according uniquely to the priority defined with the BSS external

priorities (Slots from 14 to 17).

Queuing is managed by the BSC whatever queuing information coming from the MSC are. So

an assignment request priority is set accordingly to assignRequestPriority and the mapping

associated to in the allocPriorityTable.

CAUTION!

In this mode, WPS can not be efficient because resource allocation request queuing depends

on the type of operation only: thus the priority in the WPS assignement request is not

considered (see chapter WPS - Wireless Priority Service).

In the same way, assignment request with cause emergency calls cannot be differentiated in

this mode, and are treated with priority according to assignRequestPriority.

QUEUING PROCESS

Whatever the queuing mode is, a queue is defined by its size and the maximum waiting time

beyond which it is not allowed to queue the request anymore,. set by these two parameters:

allocWaitThreshold

This parameter is a 13 slot vector. The slot number (0…12) represents the internal priority

queues and the values define the maximum number of TCH allocation requests queued for

each internal priority. The last five slots set to 5 are reserved for WPS call treatment. These

values are accumulative, so the value for one queue represents the maximum number of

requests for that queue and all the queues with lower priorities. Note that the serving

preference for these queues has an increasing order, e.g. if there are two TCH allocation

requests waiting in two different queues, when a TCH resource is released, the request with

the lowest priority is served.

Slot number 0 1 2 3 4 5 6 7 8 9 10 11 12

allocWaitThreshold n 0 n n 0 0 0 0 5 5 5 5 5

n is the integer part of (number of SDCCH sub-channels in the cell)/2.

Note: that while the TCH request is queued it remains in a SDCCH sub-channel. A queue size

longer than the number of sub-channels SDCCH in the cell is so useless. On the other hand a

value closed to the number of SDCCH channels may cause an increase of SDCCH blockingrate due to the lack of SDCCH resources.




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allocPriorityTimers

This parameter is a 13 slot vector. The slot number (0…12) represents the internal priority

queues and the values mean the maximum waiting time (in seconds) in the queue of a TCH

allocation request for each internal priority. The last five slots set to 28 are reserved for WPS

call treatment.

Slot number 0 1 2 3 4 5 6 7 8 9 10 11 12

allocPriorityTimers 5 0 5 5 0 0 0 0 28 28 28 28 28

Note: a too long timer is unrealistic as an user will not wait indefinetely.

Sum up of the recommanded value

Slot number 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

allocPriorityTable 0 8 9 10 11 12 2 2 2 2 2 2 2 2 3 0 4 2

Internal priority /queue number

0 1 2 3 4 5 6 7 8 9 10 11 12

allocWaitThreshold n 0 n n 0 0 0 0 5 5 5 5 5

allocPriorityTimers 5 0 5 5 0 0 0 0 28 28 28 28 28

• procedures coming with an external priority 0 or 15 are associated to internal

priority and queue 0, but queuing is not allowed for intercell handovers

(system rule). In this configuration, only Emergency Call can be queued forthe external priority 0.

• internal priority and queue 1 are reserved for future use

• procedures coming with an external priority from [6 to 13] or 17 are associated

to internal priority and queue 2 and queuing is allowed

• procedures coming with an external priority 14 are associated to internal

priority and queue 3 and queuing is allowed

• procedures coming with an external priority 16 are associated to internal

priority and queue 4 but queuing is not allowed

• procedures coming with an external priority from [1 to 5] are associated to

internal priorities and queues [8 to 12] and queuing is allowed (if WPS

activated)

• internal priorities and queues [5 to 7] are not used

CAUTION!

• There is no queuing for TCH in “signaling mode” (TCH overflow).

• It is important to note that even if Directed Retry Handovers are associated to

an internal priority 2 queuing is not allowed for this type of procedure, as for

the other intercell handover procedures.

• Queuing set for procedures with internal priority 0 has been intentionally

configured for Assignment Requests cause “Emergency Call” (which shouldhave in this case a NSS external priority set to 1 if in MSC driven mode).




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Indeed, the only other procedures with priority 0 are intercell handover for

which queuing is forbidden.

• It is recommended to give different BSS external priorities for the Assignment

Requests and intracell Handovers in order to prioritise the queued allocationsfor Assignment Requests. This type of procedure is more sensitive from an

end-user point of view. A user not succeeding in the assignment request will

experience an establishment failure and have to re-establish the call, whereas

in the intracell Handovers, the call is already established and even in case of

Intracell Handover failure that does not necessarily mean a call drop. The

intracell Handover may be re-tried without a real end-user impact.

Below is the flowchart summarizing the TCH allocation handling if queuing is configured as

recommended in MSC driven mode:

Note: if directed retry handover is activated, another way of leaving the queue is a directed

retry handover. Refer to Directed Retry Handover for more details.




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4.11.3 BARRING OF ACCESS CLASS

On SYS INFO messages, the list of mobile access classes that can not start a call on the cell

is broadcast. Up to V8, this list is represented by the OMC-R parameternotAllowedAccessClasses. A feature allows the modification of what is sent on SYS INFO in

case of congestion.

CAUTION!

As the MS reads SYS INFO messages every 30 seconds in idle mode, there could be a time

window where non-authorized mobiles will still be allowed, e.g. if the MS did not read the

message before the cell selection, it could start a call.

DYNAMIC BARRING OF ACCESS CLASS (ALL_4)

The mechanism consists of temporarily forbidding cell access to some of the mobiles

(according to their access class) when a congestion situation is observed. The congestion

condition is based on:

• The number of free TCH channels.

Note that TCH resources reserved for maximum priority requests (internal

priority = 0) are not considered as free TCH channels.

The parameters are numberOfTCHFreeBeforeCongestion and

numberOfTCHFreeToEndCongestion .

or

• The number of queued requests in the cell.

The parameters are numberOfTCHQueuedBeforeCongestion and

numberOfTCHQueuedToEndCongestion .

The feature is enabled at bsc level by the attribute bscMSAccessClassBarringFunction, and at

bts level by the attribute btsMSAccessClassBarringFunction.

PRINCIPLE

In case of non-congestion, only the list of mobile access classes in notAllowedAccessClasses

is not allowed to select the cell.

In case of congestion, the list of mobile access classes in accessClassCongestion is not

allowed.

Congestion ? YESNO

notAllowedAccessClassesForbidden in the cell

accessClassCongestionForbidden in the cell

Congestion ? YESNO

notAllowedAccessClassesForbidden in the cell

accessClassCongestionForbidden in the cell




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CONGESTION DETERMINATION

To enter a congestion state, either the number of free TCH must be less than

numberOfTCHFreeBeforeCongestion or the number of queued TCH requests must be greater

than numberOfTCHQueuedBeforeCongestion.

To leave a congestion state, either the number of free TCH is greater than

numberOfTCHFreeToEndCongestion or the number of queued TCH request is less than

numberOfTCHQueuedToEndCongestion.

Example with a one TRX cell where one time slot is reserved for requests with an internal

priority equal to 0:

A congestion situation may be detected each time one of the following events occurs:• allocation of a TCH resource

• queuing of a TCH resource request

• blocking of a TCH resource (O&M action)

• TDMA removal for defense or O&M reason

• detection thresholds modification

End of congestion situation may be detected each time one of the following events occurs:

• release of a TCH resource

• a queued TCH resource request is served or aborted

• unblocking of a TCH resource (O&M action)

• TDMA attribution

• detection thresholds modification

Note: The overload state duration of a cell can be monitored thanks to the counter C1714, but

that counter is effectively reported to the OMC-R only if the load of the cell is taken into

account (i.e. only if hoTraffic = enabled at cell and BSC levels).

SA0 SA1 SA2 SA3 SA0 SA1 SA2 SA3


BCCH

BCCH

SA1 SA0 Free TCHUsed TCH

time

SA0 SA1 SA2 SA3 SA0 SA1 SA2 SA3BCCH

SA3reserved TS

for priority 0

T: TDMA enter in congestion

T+1: TDMA is still in congestion

T+2: TDMA gets out of congestion

numberOfTCHFreeBeforeCongeston = 1

numberOfTCHFreeToEndCongeston = 3



BCCH

BCCH

SA1 SA0 Free TCHUsed TCH

time

SA0 SA1 SA2 SA3 SA0 SA1 SA2 SA3BCCH

SA3reserved TS

for priority 0

T: TDMA enter in congestion

T+1: TDMA is still in congestion

T+2: TDMA gets out of congestion

numberOfTCHFreeBeforeCongeston = 1

numberOfTCHFreeToEndCongeston = 3




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V15.0 CHANGES OF DYNAMIC BARRING OF ACCESS CLASS (ALL_4)

The previous “access class barring” mechanism can be improved on 3 main points:

• The list of forbidden access classes is fixed, so the same customers are

always impacted.

• The number of barred access classes is fixed, so the number of barred

access classes may be insufficient.

• The mechanism is triggered on TCH allocation or release basis, but due to the

Erlang law (which induces sudden traffic modification) and because the MS

rereads the SYS INFO (only every 30 seconds), that mechanism could be

improved.

To ensure the functionning of the new mechanism, two levels of barring are created and run at

the same time:

• One level (low level) to provide point 1 and point 3

• One level (high level) to provide point 2

This feature is controlled by bscMSAccessClassBarringFunction on the bsc object and

btsMSAccessClassBarringFunction on the bts object.

HIGH LEVEL MECHANISM DESCRIPTION

To provide point 2, the number of access classes can be modified (additional or less) in order

to adapt to the length of congestion level. Once the cell enters in the congestion state, a

supervision timer is set, and every 3 minutes (system rule), an adaptation is made based on

the new cell congestion state:

• If the cell is still in the congestion state, 2 additional access classes are barred

(assuming they are not all barred)

• If the cell is not in the congestion state, 2 less access classes are barred (until

none are barred)

Once the cell is no longer in the congestion state, and if no access classes are barred, the

supervision timer (3 minutes) is stopped.

This mechanism is independent of the low level of barring mechanism.

Beginning of congestion:

3 minutes timer is setEnd of congestion :

3 minutes timer

is running

Congestion level

time

End of

congestion

Beginning of

congestion

[0 to 2]Number of access

classes barred [2 to 4] [4 to 6] [6 to 4] [4 to 2] [2 to 0]

No more classes

barred: 3 minutes

timer is stopped

3 minutes


3 minutes timer is setEnd of congestion :

3 minutes timer

is running

Congestion level

time

End of

congestion

Beginning of

congestion

[0 to 2]Number of access

classes barred [2 to 4] [4 to 6] [6 to 4] [4 to 2] [2 to 0]

No more classes

barred: 3 minutes

timer is stopped

3 minutes




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The barred access classes rotate inside the 3 minute time period according to the low level

mechanism of barring described below:

LOW LEVEL MECHANISM DESCRIPTION

Two parameters are important in this mechanism: the periodicity and the

accessClassCongestion parameter.

Periodicity: the congestion condition is still triggered on a TCH allocation or TCH release

basis, but once the congestion condition is triggered, a 60 seconds interval (system rule) is

used to periodically change which access classes are barred.

accessClassCongestion parameter: this parameter is a list of access classes which are

eligible to be barred during the congestion condition. The principle is that, during each 60

seconds interval of congestion, a different subset of access classes (and thus a different set of

mobile sets) may be barred. Access classes 11 to 15 are managed and can be automatically

barred if they are included in the accessClassCongestion parameter. They can not beautomatically barred if they are not in the accessClassCongestion parameter.

LOW AND HIGH LEVEL MECHANISM EXAMPLE

Let us take an example for the accessClassCongestion = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9].

Next time the cell is in congestion, since the last barred access classes are memorised in the

BSC, the new barred access class are the 2 followings in the list of access classes indicated in

the accessClassCongestion parameter.

In case the BSC12000 switchover, TMU reset for BSC3000 or lock/unlock of the cell, the first

barred access class is the first one in the list of access classes indicated in the

accessClassCongestion parameter.

In case the feature is turned off (cell or BSC level), the BSC sends immediately the system

information with notAllowedAccessClasses parameter included whatever is the cell congestion

status.


3 minutes timer is set

Congestion level

time

Number of access classes

barred

60 seconds3 minutes

Barred access classes [0,1] [2,3] [4,5] [6,7,8,9] [0,1,2,3] [4,5,6,7] [8,9]

[0 to 2] [2] [2] [2 to 4]

End ofcongestion

Beginning of

congestion

[4] [4] [4 to 2]


3 minutes timer is set

Congestion level

time

Number of access classes

barred

60 seconds3 minutes

Barred access classes [0,1] [2,3] [4,5] [6,7,8,9] [0,1,2,3] [4,5,6,7] [8,9]

[0 to 2] [2] [2] [2 to 4]

End ofcongestion

Beginning of

congestion

[4] [4] [4 to 2]




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In case the accessClassCongestion parameter is modified while the cell is in congestion, the

list of access classes to be barred will be re-evaluated on the 60s timer expiry, and on the 3

minutes timer expiry, the evaluation will be done on this new list (and not on the list of the

previous 3 minutes timer expiry).

NOTALLOWEDACCESSCLASSES PARAMETER MANAGEMENT

The following principle applies:

• In case of non congestion, only the list of mobile access classes in

“notAllowedAccessClasses” is not allowed to select the cell

• In case of congestion, the list of mobile access classes in

“accessClassCongestion” is not allowed.

Usually all users are authorized, and the notAllowedAccessClasses list is empty.

With the redefinition of the access class barring functionality, the management of the

notAllowedAccessClasses parameter is modified in the following way:

• In case of non congestion, only the list of mobile access classes in the

“notAllowedAccessClasses” parameter is not allowed to select the cell: there

is no modification compared to the previous management.

• In case of congestion, the accessClassCongestion parameter is used to

process access classes rotation on all the access classes listed in the

accessClassCongestion except on the access classes listed in the

notAllowedAccessClasses parameter, which remain barred during the

congestion.

Let us take the example for the accessClassCongestion = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] and

notAllowedAccessClasses = [3, 4].

This means, as described here above, that access class rotation will be done on the following

access class list = [0, 1, 2, 5, 6, 7, 8, 9] and that access classes 3 and 4 remain barred during

the congestion.




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4.11.4 RADIO LINK FAILURE PROCESS (RUN BY THE MS)

It is performed by the MS in dedicated mode on SACCH blocks.

RLC counter is initialized to radioLinkTimeout at the beginning of a dedicated mode.

IF good SACCH block

THEN RLC = Min[RLC+2, radioLinkTimeout]

IF bad SACCH block

THEN RLC = RLC - 1

If RLC reaches 0, then call is dropped and re-establishment is tried if reselection is made on a

cell with CallReestablishment set.

4.11.5 RADIO LINK FAILURE PROCESS (RUN BY THE BTS)

The FrameProcessor sets the CT counter to 0 at channel activation

On each correct SACCH:

IF good SACCH block AND IF (CT = 0)

THEN CT = 4*rlf1 + 4

ELSE CT = Min[4*rlf1 + 4,CT+rlf2]

IF bad SACCH block

CT = max(0,CT-rlf3)

If CT reaches 0, a connection Failure Indication is sent to the BSC every T3115, until a

Deactivate Sacch or RF Channel Release message is received.

This process is started when the first SACCH frame is received correctly, and the CT counter

is set according to rlf1 value. If SACCH frame is not received, then the radio link failure

process is not started, CT value is kept to zero and is not modificated.

Interest of the algorithm: the quality of an uplink communication is now considered for the

decision to cut a communication.




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4.11.6 CALL REESTABLISHMENT PROCEDURE

The call re-establishment procedure allows a mobile station to resume a connection in

progress after a radio link failure, possibly in a new cell and possibly in a new location area.

So this feature avoids losing calls, improving in that way the quality of service. Moreover, in

case of call drop, it reduces the SICD load by avoiding the subscriber to hang off and on.

The Call Re-establishment can be launched following 2 different procedures depending on the

entity which detects the radio link failure:

a) The radio failure is first seen at the MS side (RadioLinkTimeOut value):

The mobile sends a call-reestablishment on a selected cell (previous one or

new one) and the MSC re-allocate new resources. The old resources are

free by the BSS after the rlf1 timer has expired.

b) The radio failure is first seen at the BSS side:

The BTS send a radio_link_failure message to the BSC after rlf1 has

expired, the BSC releases the radio resources and in the same time the

MSC activates the t3109 timer and waits a call-reestablishment. Then, when

the MS has detected the radio link failure as well, it performs the selection

and sends a channel request on the selected cell.

To attempt a call re-establishment on a cell, the parameter callReestablisment of the cell will

be set to “allowed” and the cell will not be barred (see chapter Barring of access class).

The mobile station is not allowed under any circumstance, to access a cell to attempt call re-

establishment later than 20 seconds after it detects the radio link failure causing the call re-

establishment attempt.

The mobile station shall perform the following algorithm to determine which cell to use for the

call re-establishment attempt within 5 seconds max:

• The level measurement samples taken on the serving cell BCCH carrier and

on neigbhor cells carriers (carriers indicated in the BA (SACCH) received on

the serving cell) received in the last 5 seconds shall be averaged.

• The carried with the highest average received level is selected.

• On this carrier the MS shall attempt to decode the BCCH data block

containing the parameters affecting cell selection.

• If the parameter C1 is greater than zero call re-establishment shall be

attempted on this cell.• If the MS is unable to decode the BCCH data block or if the call re-

establishment is not allowed, the carrier with the next highest average

received level shall be taken, and the MS shall repeat steps 2) and 3) above.

• If the cells with the 6 strongest average received level values have been tried

but cannot be used, the call re-establishment attempt shall be abandoned.

Beware, during a re-establishment attempt the mobile station does not return to idle mode,

thus no location updating is performed even if the mobile is not updated in the location area of

the selected cell, however the mobile station will update its location area at the end of the call.

Generally a call re-establishment procedure lasts from 4 seconds to 20 seconds max.




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4.11.7 CALL CLEARING PROCESS (RUN BY BTS)

This process is used to drop calls with mobiles which are located too far away from a serving

cell and that may disturb other communications on adjacent time slots.

Every runCallClear:

IF (MS_BS_Dist > CallClearing)

THEN call needs clearing.

4.11.8 INTERFERENCE MANAGEMENT (BTS AND BSC)

All interference measurements performed by the BTS on the idle channels are performed in

Watts. Each sample is computed in Watt before being translated in dBm and sent to the L1M.

This method of calculation provides a result which is 2.5 dB higher than the one directly

performed in dB.

Every averagingPeriod, BTS computes Interference levels of idle channels (SDCCH and TCH)

according to the 4 defined thresholdInterference (resulting in 5 Interference ranges) and sends

this information to the BSC. It is therefore possible to monitor interference levels at the OMC.

The BSC will use RadChanSelIntThreshold parameter in order to sort available channels

according to their interference level. Thus the BSC will allocate channels using the following

priority:

• Hop and low_IF

• NoHop and low_IF

• Hop and (high_IF or just released)

• NoHop and (high_IF or just released).

Note: No interference level management is performed for PDTCH channel, Therefore the level

status of PDTCH resource is always high level (bad level).

4.11.9 UPLINK DTX

DTX is possible both downlink and uplink, but configuration and activation are uncorrelated in

the 2 mechanisms.

The uplink DTX feature is enabled when dtxMode parameter is set to “msShallUseDtx” (the

shall is dependent on the MS decision or capability.

When uplink DTX is activated on the network, MS gets the information from the BTS

(activation parameter). Then it is allowed to perform uplink DTX, i.e. to transmit

discontinuously only a subset of TCH bursts.

If the MS perform DTX on a call, the minimum number of transmitted bursts is 12 (out of 104

for a complete reporting period of 480ms).

The 12 bursts correspond to the 4 SACCH + 8 fixed positioned TCH bursts.




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4.11.10 DOWNLINK DTX

In the same way as the mobile, the BTS is able to transmit discontinuously (cellDtxDownLink

parameter, bts object).

The activation of downlink DTX follows depends on :

• authorisation for the BSS to use DL DTX, given by the MSC to the BSC at

assignment request, dynamically on a call-by-call basis

• The value of cellDtxDownLink parameter (bts object)

• The type of radio channel : voice half-rate, voice full-rate, cicuit data

• The values of certain bits in the bscDataConfig file (bits n°1, n°2 and n°3 of label 64)

MSC AUTHORISATION

On a call per call basis, the MSC may forbid the BSS to use Downlink DTX.

The MSC indicates this to the BSC by including a 1-bit long field called “DTX Downlink Flag”

inside BSSMAP Assignment Request (for call setup) or BSSMAP VBS/VGCS Assignment

Request (for group call setup, GSM-R only) or BSSMAP Handover Request (for incoming

external handover of a call coming from another BSS) :

- If “DTX Downlink Flag” is present and if DTX Downlink Flag = 1, then the MSC forbids the

use of DL DTX for that particular call

- If “DTX Downlink Flag” is absent or if DTX Downlink Flag is present and DTX Downlink

Flag = 0, then the MSC does not forbid the use of DL DTX for that particular call

In the second case, the decision to use DL DTX for that call is left entirely up to the BSS and

depends on BSS configuration parameters and the type of channel.

CELLDTXDOWNLINK

If cellDtxDownLink = disabled in the cell, then Downlink DTX is unconditionally turned off in

the cell for all types of call (voice and circuit-switched data).

So, cellDtxDownLink = enabled is a necessary condition to activate downlink DTX in the cell,

but it is not sufficient. It further depends on the type of channel (circuit data, voice half-rate,

voice full-rate).




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TYPE OF CHANNEL

CIRCUIT-SWITCHED DATA CHANNELS

DTX downlink is unconditionally turned off for circuit-switched data channels, even if

cellDtxDownLink = enabled.

Note : Bit n°1 of label 64 of bscDataConfigfile, called “DTX Downlink in data”, is not used any

longer in the software. Whatever its value, and whatever the value of cellDtxDownLink, DTX

Downlink is disabled for CS data channels.

FULL-RATE VOICE CHANNELS

If bit n°2 of label 64, called “DTX Downlink FR”, is equal to 1 : DTX Downlink is unconditionally

turned off for FR voice channels. This applies to all types of full-rate codecs supported by the

BSS : AMR FR, EFR and FR.If bit n°2 = 0, and if cellDtxDownLink = “enabled” in the cell, then downlink DTX is used on all

FR Voice channels, provided that its use has not been explicitly forbidden by the MSC at

assignment request stage.

By default, label 64 bit n°2 = 0 so by default DL DTX is activated for FR voice calls.

HALF-RATE VOICE CHANNELS

If bit n°3 of label 64, called “DTX Downlink HR”, is equal to 1 : DTX Downlink is unconditionally

turned off for AMR HR voice channels.

If bit n°3 of label 64 = 0, and if cellDtxDownLink = “enabled” in the cell, then downlink DTX isused on all AMR HR Voice channels, provided that its use has not been explicitly forbidden by

the MSC at assignment request stage.

By default, label 64 bit n°3 = 0 so by default DL DTX is activated for FR voice calls.

SUMMARY

The table below summarises the activation scenarios of DL DTX :

DTX DL flag(from MSC)

cellDtxDownLink

Label 64 bit1

Label 64 bit2

Label 64 bit3

DL DTX forCS data

DL DTX forFR voice

DL DTX forHR voice

1 any value any value any value any value disabled disabled disabled

0 or absent disabled any value any value any value disabled disabled disabled

0 or absent enabled 0 0 0 disabled enabled enabled

0 or absent enabled 0 0 1 disabled enabled disabled

0 or absent enabled 0 1 0 disabled disabled enabled

0 or absent enabled 0 1 1 disabled disabled disabled

0 or absent enabled 1 0 0 disabled enabled enabled

0 or absent enabled 1 0 1 disabled enabled disabled

0 or absent enabled 1 1 0 disabled disabled enabled

0 or absent enabled 1 1 1 disabled disabled disabled




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4.12. EMLPP PREEMPTION

4.12.1 PRINCIPLE OF EMLPP

DEFINITIONS

eMLPP priority : eMLPP priority associated to a call for preemption purposes. The BSC

transparently conveys eMLPP priority between the mobile and the NSS. The BSC does not

process this eMLPP priority.

NSS external priority (also known as BSSMAP priority) : priority associated to a call by the

NSS in the assignment or handover procedure. This priority is sent by the NSS to the BSS and

may then be used by the BSS for queuing or for preemption. Unlike the eMLPP priority, it is

transparent to the mobile.

BSS external priority : queuing priority defined via OMC parameter settings. Each type of

procedure is associated to a BSS external priority for queuing. This priority is used by the BSS

but it is strictly local, therefore the NSS and MS are not aware of it.

internal priority : this priority is local to the BSS. Therefore the NSS and MS are not aware of it.

It is an output of the allocprioritytable.

PRINCIPLE

eMLPP is an extension to GSM networks of the existing MLPP service for fixed lines.

eMLPP covers 2 basic aspects :

• Resource preemption for mobile originated or mobile terminated call establishment

procedures

• Called party preemption for mobile terminated calls

RESOURCE PREEMPTION

eMLPP allows the network to preempt resources from ongoing calls (circuits on the A interface

and/or radio resources in the BSS) to allocate them to an incoming call of greater priority :

o Preemption on the A interface is fully managed (decision and execution), on a per call

basis, by the NSS.

o Preemption on the Radio interface is executed, on a per call basis, by the BSS.

However, the decision to allow the preemption comes from the NSS because the NSS

is in charge of the Call Control procedures.




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• By the BSS in the PAGING REQUEST type 1, 2 ,3 messages sent to the mobile on

the PCH channel. The purpose of including eMLPP priority in paging requests is used

by mobiles who are engaged as listeners in a group call to decide to leave the group

call or not.

• By the NSS in the PAGING message sent to the BSS. The purpose of including

eMLPP priority in BSSMAP PAGING message is so that the BSS may include it in the

Paging Request (see previous bullet point)

• By the NSS in the SETUP message sent to the mobile for mobile-terminated call

establishment. It indicates to the mobile already engaged in a call whether to perform

called party preemption or not.

• By the NSS in the CALL PROCEEDING message by the network to the mobile. This

message is sent by the network to the calling mobile station to indicate that the

requested call establishment information has been received. In this message, the NSS

indicates to the mobile station the eMLPP priority level that the NSS has granted tothe call.

EMLPP SUBSCRIPTION

Two precedence levels are defined by subscriber and stored at the HLR:

• Subscriber’s Maximum Precedence Level. The subscriber may originate a call with a

precedence level up to his maximum precedence level

• Subscriber’s Default Priority Level. In the case no precedence level is sent in the “CM

service request” message, this level is used as the priority of the call

EMLPP PRIORITY SETTING AT MO CALL SETUP

For Mobile Originated point to point calls, the eMLPP priority precedence level is included

inside the CM SERVICE REQUEST message sent by the mobile to the network. Its value is

set as follows.

EMLPP SUBSCRIBER

The user may select an eMLPP priority value for the call. If he does not, the precedence is set

to its default value by the mobile.

The mobile checks that the priority is within the provisioned range.

The MSC validates the priority value, and possibly reduces it to the subscriber’s maximum

precedence stored in the VLR




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NON-EMLPP SUBSCRIBER

A default priority level is set by the MSC.

4.12.3 PREEMPTION ATTRIBUTES

OVERVIEW

Each call that comes into a BSC from the NSS (via ASSIGNMENT REQUEST or HANDOVER

REQUEST) has radio resource preemption capabilities, that have been allocated to it by the

NSS.

BSS Radio resource Preemption works as follows. In case of a lack of available radio

resources, the BSC is capable of allocating currently occupied resources to incoming calls that

have a preemption capability, by preempting resources of ongoing calls that are preemption-vulnerable.

Only TCH channels in dedicated mode, or PDTCH channels used for a CS call, are subject to

preemption.

The preemption mechanism of radio resources that is detailed here is based on the “BSSMAP

Priority” Information Element carried in ASSIGNMENT REQUEST or HANDOVER REQUEST

messages at the BSSMAP layer of the A interface. The BSSMAP priority is the input given to

the BSC by the MSC. The “BSSMAP Priority” Information Element contains preemption

attributes that are the result of the eMLPP functionality implementation in the NSS.

PREEMPTION ATTRIBUTES

The BSSMAP priority information element of a given call is optional and contained in

ASSIGNMENT REQUEST and HANDOVER REQUEST. It is sent by the NSS to the BSS, and

it provides the BSS with the eMLPP preemption capability of the call.

IF THE BSSMAP PRIORITY IS PRESENT

The BSSMAP priority information element is made up of the following 4 attributes : PCI, PVI,QA and Priority.

PCI: preemption capability indicator. The PCI attribute is a flag that specifies whether the call

is allowed to preempt another one or not. It is applicable while negotiating the allocation of

resources :

• PCI = 0 : this allocation request (resulting from assignment or handover) cannot

trigger the preemption procedure.

• PCI = 1 : this allocation request (resulting from assignment or handover) can trigger

the running of the preemption procedure.




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PVI: preemption vulnerability indicator. The PVI attribute is a flag that specifies whether the

call is allowed to be preempted by another call or not.

• PVI = 0 : this connection is not vulnerable to preemption.

• PVI = 1 : this connection is vulnerable to preemption.

QA: queueing allowed indicator. The QA attribute is a flag that specifies whether the call is

allowed to b a queueing procedure or not :

• QA = 0 : queuing is not allowed

• QA = 1 : queuing is allowed

PRIORITY : priority level. The priority attribute is an integer value in the range 1 ... 14 that

specifies the level that is applied to the call. Values 0 and 15 indicate “priority not used”.

It is built by the MSC thanks to a hardcoded lookup table that maps the eMLPP priority of the

call to the BSSMAP priority.

eMLPP priority value BSSMAP priority value

A (strongest priority) 1

B 2

0 3

1 4

2 5

3 6

4 (weakest priority) 7

IF THE BSSMAP PRIORITY IS ABSENT

If the BSSMAP priority is absent, the assignment request for that call is treated by the BSS as

though the flags were defined as follows :

• PCI = 0: no preemption capability;

• PVI = 0: no vulnerability;

• QA = 0: queueing not allowed;

• priority level = 0: no priority.

4.12.4 BSS RADIO RESOURCE PREEMPTION ALGORITHM

PROCEDURE

Definition : a vulnerable resource is a radio resource whose PVI is defined and equals 1.




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Upon receiving an ASSIGNMENT REQUEST or a HANDOVER REQUEST, the BSC follows

the following allocation algorithm :

• If there is an available radio resource, the BSC immediately performs the allocation

without invoking the preemption procedure;

• If there is no available radio resource :

o If PCI = 1 attribute is set for the request, and if a vulnerable resource (PVI = 1)

is available whose priority is strictly weaker than the request’s priority, the

BSC triggers the preemption procedure : the BSC starts the release of the

active call using this vulnerable resource and starts a specific internal timer

(Tpreempt).

If the release of the vulnerable resource is completed before expiry of

Tpreempt, or if another resource is freed up in the meantime, the

assignment is successful.

if Tpreempt expires before the resource is freed up, the preemption

procedure stops and the BSC declares an assignment failure. No

queuing or directed retry is attempted.

o If PCI is absent or if PCI = 0 or if no vulnerable resource exists or if the

weakest priority of the existing vulnerable (PVI =1) resources is at least as

strong as the request’s priority, the BSC does not start a preemption

procedure. Instead :

If allowed, the queuing and directed retry procedures are started,

Otherwise the BSC declares an assignment failure.

PREEMPTION TIMER

The preemption timer value Tpreempt is computed from T3111 timer ( t3111 parameter) as

follows:

Tpreempt = TdeactAck + (4 x T3111)

Tdeactack = 5 seconds (hard-coded).

VULNERABLE TCH SELECTION CRITERIA

The selection algorithm differs depending on the type of transceiver : DRX and DCU2. To

simplify, we assume that only DRX are used (not DCU2).

RANKING OF OCCUPIED TCH RESOURCES

To be considered a possible candidate for preemption by the BSC, a TCH must first fulfill the

following requirements :

o the TCH must be occupied by a FR voice call,




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o If the circuit data allocation request concerns the CSD 14.4 service and if the bts

object parameter data14-4OnNoHoppingTs = enabled, the preferred “busy TCH” pool

is the non-hopping one.

o If the circuit data allocation request concerns the CSD 14.4 service and if the bts

object parameter data14-4OnNoHoppingTs = disabled, the preferred “busy TCH” pool

is the hopping one (same a speech allocation request).

o If the circuit data allocation request concerns CSD services other than 14.4, the

preferred “busy TCH” pool is the non-hopping one(same a speech allocation request).

4.12.5 ACTIVATION PARAMETER

BSS Radio resource preemption must be authorised by a specific O&M parameter :

preemptionAuthor :

• Class 3

• signallingPoint object

• range : forbidden, authorizedWithRelease, authorizedWithForcedHO

preemptionAuthor = “forbidden” means that the BSC never performs radio resource

preemption, whatever the priority and PCI/PVI flags’ values.

preemptionAuthor = “authorizedWithRelease” means that the BSC is allowed to perform radio

resource preemption if necessary and if authorised by the MSC.A successful preemption

results in the preempted call being released.

preemptionAuthor = “authorizedWithForcedHO” means the same thing as preemptionAuthor =“authorizedWithRelease” in the current implementation, despite the different name.

4.12.6 EMLPP PREEMPTION VERSUS PDTCH PREEMPTION

PDTCH “preemption” consists in the BSC negotiating with the PCU to be allowed to use (to

“preempt”) a PDTCH for a CS call.

Although the same word is used, PDTCH “preemption” is not the same as eMLPP preemption.

In particular, PDTCH preemption is targeted on a chosen resource, whereas eMLPP

preemption is not.

PDTCH PREEMPTION

o The BSC receives an allocation request from the MSC

o The BSC chooses a radio resource for that particular allocation request.

o If the chosen resource is a PDTCH, the BSC starts the preemption negotiation with

the PCU. No other resource can be used instead, even if a TCH is freed in the

meantime.




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EMLPP PREEMPTION

o The BSC receives an allocation request from the MSC

o The BSC chooses a preemptable radio resource and starts the release of the call

currently using that resource.

o In parallel, while the preemption procedure is ongoing, the BSC puts the allocation

request that was the cause of the preemption inside a special queue entirely

dedicated to preemption-capable allocation requests.

o The first radio resource that becomes available is allocated to the preemption request

that is at the front of the queue. Therefore the radio resource that was preempted

originally is not necessarily allocated to the request which initially triggered that

particular preemption.

4.12.7 INTERWORKING

HANDOVER

During handover procedures, preemption in best cell is always preferred than fallback to

another one. Preemption leads to favour attempting to obtain a radio resource in the first cell

of the handover list (ensures better quality, but may cause additional delay to the handover

procedure completion), even though a radio resource may be immediately free in a further cell

in the list.

DIRECTED RETRY

If preemption is authorised (i.e. preemptionAuthor = “authorizedWithRelease”), and if no

resource is free, the BSC first looks to see, based on the PVI flag and the relative BSSMAP

priorities, whether a resource could be preempted.

If so, the BSC starts the preemption procedure. Then, either the preemption (and the

assignment) succeeds, or the BSC returns an assignment failure. Directed Retry cannot be

attempted as a fallback.

Therefore, Directed retry may be attempted only after the BSC has decided not to trigger thepreemption procedure (due to lack of potential candidate resources, e.g. PVI of all TCH = 0).

QUEUING

As for Directed retry, queuing may be attempted only after the BSC has decided not to trigger

the preemption procedure (due to lack of potential candidate resources, e.g. PVI of all TCH =

0). To solve a congestion issue, preemption is always considered first by the BSC. If a

preemption procedure is started and if it fails, queuing may not be attempted as a fallback : the

assignment request results in an assignment failure.




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Also, the BSS priority table (allocPriorityTable) is not used by the BSS in the preemption

procedure. Only the external BSSMAP priority given by the MSC is considered by the BSC in

the preemption algorithm, regardless of the corresponding internal priority given by the BSS

priority table.

RESERVED RADIO RESOURCES

Reminder : it is possible to reserve radio resources to assignment requests of internal priority

= 0 thanks to the allocPriorityThreshold parameter. When the number of free resources falls

below allocPriorityThreshold , these remaining free resources may only be allocated to

assignment requests of internal priority = 0.

Even preemption-capable assignment requests cannot use these free timeslots if the value of

their internal priority is different from 0. They have to preempt ongoing calls on other timeslots

and leave these reserved timeslots free.

4.12.8 RESTRICTIONS

Network resources (both radio channels and fixed circuits) used by emergency calls (TS12

service) may not be preempted.

SDCCH channels may not be preempted.

The following TCH channels may not be preempted :

o TCH channels used for signalling (TCH overflow)

o TCH channels used for HR calls

All other TCH, including those used for data calls, are preemptable provided that PVI = 1.

In the very first phase of a mobile originated call establishment, in case there are no SDCCH

and no TCH available, a Channel Request is not capable of triggering a preemption.




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transmit paging messages for the paging group A. This space is necessary to locate several

paging groups.

This parameter is deeply involved in the time needed to establish a call when a paging

message is coming. For instance, if a paging command is to be transmitted in a paging group

P1 just after the paging group P1 occurrence, the paging command will have to wait for at

least noOfMultiframesBetweenPaging x 240ms to be transmitted.

If noOfMultiframesBetweenPaging = 8, the time waited to transmit a paging message can be

of 2 seconds without any other delays.

From the configuration, paging group occurences are determined. In the previous example,

the paging groups will be split as follows:

Nb of Paging groups = (na - nb) x nc

• na = number of CCCH groups per BCCH multiframe• nb = noOfBlocksForAccessGrant

• nc = noOfMultiframesBetweenPaging

Note: see chapter Paging Parameters for more information on this parameter recommended

values.

noOfMultiframesBetweenPaging has also an influence on mobile battery consumption and on

reselection reactivity (see chapter Effects of “noOfMultiFramesBetweenPaging” on Mobile

Batteries and Reselection Reactivity).

4.13.2 PAGING COMMAND REPETITION PROCESS (RUN BY BTS)Paging messages are systematically repeated. Three (3) parameters will manage paging

message repetitions:

• nbOfRepeat

defines the number of times a paging message will be repeated by the BTS

• delayBetweenRetrans

defines the number of occurrence between 2 repetitions of the same paging

group

• retransDuration

defines the maximum time allocated to broadcast a paging message

B C

C H

B C

C H

B C

C H

B C

C H

F C

C H

S C H

F C

C H

S C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

F C

C H

S C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

F C

C H

S C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

I D

L EBlock

bookedfor AGCH

Paging

groupnb0 (A)

Paging

groupnb1

B C C H

B C C H

B C C H

B C C H

F C C H

S C H

F C C H

S C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

F C C H

S C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

F C C H

S C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

I D L EBlock

booked

for AGCH

Paging

group

nb2

Paging

group

nb3

B C C H

B C C H

B C C H

B C C H

F C C H

S C H

F C C H

S C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

F C C H

S C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

F C C H

S C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

I D L EBlock

booked

for AGCH

Paging

group

nb0 (A)

Paging

group

nb1

FN0

FN1

FN2

F C

C H

S C H

F C C H

S C H

F C C H

S C H

B C

C H

B C

C H

B C

C H

B C

C H

B C

C H

B C

C H

B C

C H

B C

C H

F C

C H

S C H

F C

C H

S C H

F C

C H

S C H

F C

C H

S C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

F C

C H

S C H

F C

C H

S C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

F C

C H

S C H

F C

C H

S C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

I D

L EBlock

bookedfor AGCH

Paging

groupnb0 (A)

Paging

groupnb1

B C C H

B C C H

B C C H

B C C H

B C C H

B C C H

B C C H

B C C H

F C C H

S C H

F C C H

S C H

F C C H

S C H

F C C H

S C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

F C C H

S C H

F C C H

S C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

F C C H

S C H

F C C H

S C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

I D L EBlock

booked

for AGCH

Paging

group

nb2

Paging

group

nb3

B C C H

B C C H

B C C H

B C C H

B C C H

B C C H

B C C H

B C C H

F C C H

S C H

F C C H

S C H

F C C H

S C H

F C C H

S C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

F C C H

S C H

F C C H

S C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

S D C C H

F C C H

S C H

F C C H

S C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

S A C C H

I D L EBlock

booked

for AGCH

Paging

group

nb0 (A)

Paging

group

nb1

FN0

FN1

FN2

F C

C H

S C H

F C

C H

S C H

F C C H

S C H

F C C H

S C H

F C C H

S C H

F C C H

S C H




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The following rule is checked at the OMC-R:

retransDuration > (delayBetweenRetrans + 1) x nbOfRepeat

This inequality is to insure at least nbOfRepeat paging transmissions when there is no

blocking on paging channel.

See chapter Paging Parameters and chapter GSM Paging Repetition Process Tuning to find

engineering rules to set these parameters.




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4.13.3 REQUEST ACCESS COMMAND PROCESS

RACH are used when mobiles request a channel to establish a communication (both

terminated and initiated calls, see chapters Mobile Terminating Call and Mobile Originating

Call). Request management is configurated (nb of repetitions, time between repetitions...) at

the OMC-R thanks to different parameters.

4.13.4 REQUEST ACCESS COMMAND REPETITION PROCESS

After sending the initial CHANNEL REQUEST message, the MS starts a timer (T3120) and

listens to AGCH logical channel. When this timer expires and number of retransmissions does

not exceed maxNumberRetransmission , the MS repeats the CHANNEL REQUEST.

See also chapter GSM Paging Repetition Process Tuning.

PHASE 1 MOBILES

When the timer is started, a random value n is drawn with equal probability between 0 and N-1

where N is:

• for the initial access: max (8, numberOfSlotsSpreadTrans)

• for next attempts: numberOfSlotsSpreadTrans

T3120 is set so that there are n RACH slots between T1 and the expiry of T3120. T1 is a fixed

delay thanks to the configuration of the BCCH:

• before initial access, T1 = 0

• after initial access, T1 = 250 ms (for non combined CCCH)

• after initial access, T1 = 350 ms (for combined CCCH)

time

Fixed delay whose

value depends on

whether or not the

BCCH is combined

Variable delay from 0 to

numberOfSlotsSpreadTrans – 1

RACCH

time

Fixed delay whose

value depends on

whether or not the

BCCH is combined

Variable delay from 0 to

numberOfSlotsSpreadTrans – 1

RACCH




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PHASE 2 MOBILES

Rec 04.08 have been modified to avoid double allocation (see chapter Paging Parameters).

When the timer is started, a random value n is drawn with uniform probability distribution in the

interval [S, S+1, ..., S+T-1]:

• where T is numberOfSlotsSpreadTrans

• where S depends on the BCCH configuration and on T (see following table).

numberOfSlotsSpreadTrans S on non-combined BCCH S on combined BCCH

3, 8, 14, 50 55 41

4, 9, 16 76 52

5, 10, 20 109 58

6, 11, 25 163 86

7, 12, 32 217 115

4.13.5 I MULTIPAGING COMMAND MESSAGE

The multipaging command message is a Nortel Specificity. The principle of this

implementation is to form group of paging on the Abis interface. Before BSS V14.3.1, for each

paging message receives from the MSC; one paging message is sent on Abis interface to a

target cell.

The aim of this feature is to reduce the congestion and overload messages on Abis interface.

In order to achieve this goal, a new BSC timer Called T_Paging_Group was introduced, to

define the minimum of time between two occurrences of multi paging command messages on

Abis interface.

Therefore, at emission of one multi paging command message, the BSC starts

T_Paging_Group.

If during T_Paging_Group, more than 10 paging messages are received, then only the 10

first messages are stored, thus others messages are discarded.

time

Fixed delay whose

value depends on

BCCH configuration and

numberOfSlotsSpreadTrans

Variable delay set according to


time

Fixed delay whose

value depends on

BCCH configuration and


Variable delay set according to





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At T_Paging_Group expiry, either no paging message is received from the MSC or at least

more than one paging message is stored and the BSC sends these messages to the BTS.

In both cases the BSC restarts the timer.

Note: The maximum length is 12 paging messages.

A multi paging command is sent by the BSC in two cases:

• As soon as the 12 first paging are received by the BSC, a paging group

message is sent to the BTS leading to avoid discarding paging messages

and waiting for T_Paging_Group timer expiry.

• If T_Paging_Group timer is reached and at least one paging message is

received, a multi paging command is sent

Caution!

The value of this T_Paging_Group is set to 200ms. Only CS paging use I Multipagingcommand, therefore the PS pagings are not combined. Thus a single paging I is used for data

paging.

The following figure illustrates the principles of multipaging command

The two major improvements bring by this feature are:

• a large Lap D bandwidth associated to the BCCH for non-paging messages,

which provides a better quality of service,

• a reduction of the CPU load generated by paging messages at BSC and BTS

levels.

However, it induces a delay (average=100ms, min=0ms, max=200ms) during the paging

management at the BSC level, and the mobile terminated call setup time is lightly increased.

CAUTION!

Note: As this feature increases the BSS capacity, since BSS V14.3.1 it is activated by default.

Pa in MS4

BTS

BSCMSC

Paging MS1

Multi paging command

T_Paging_groupPa in MS2

MS1, MS2, MS3

Pa in MS3

T_Paging_group

Multi paging command

MS4




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4.13.6 UI MULTIPAGING COMMAND MESSAGE

PRINCIPLE

Each time a data request message (I frame on LapD) is used to convey a multipaging

message to the BTS, the BSC has to wait for an acknowledgement before sending the

next multipaging message. Therefore, the paging process is RTD dependent.

Using the Unit Data Request message (UI frame on the LapD), no acknowledgement

is required before sending the next frame, which decreases the lapd bandwidth

associated to the BCCH TRX for paging messages.

Hence, whatever is the paging number per second, the quality of service is increased

and more especially in case of large location area which generates high number ofpaging messages or during exceptional events.

This feature is introduced in V15.1.1 and it allows, at equivalent paging messages

number, to better fill the downlink lapd bandwidth associated to the BCCH for paging

messages and to decrease the use of the uplink lapd bandwidth. Hence it increases

the lapd bandwidth associated to the BCCH for non-paging messages.

SPECIFICATIONS OF THE UI MULTIPAGING COMMAND MESSAGE

UI Multipaging command message uses the same mechanisms (to group the paging

command messages) as the I Multipaging command message described in below

except the ones described here under.

In order to build the UI Multipaging message, the BSC timer T_Paging_Group is

used, which defines the maximum time between 2 occurrences of UI Multi Paging

Command message on the Abis interface.

The BSC starts T_Paging_Group at emission of one UI Multi Paging Command

message.

Until T_Paging_Group expiry, as soon as a MultiPaging command message has

stored 12 unit paging command messages, it is transmitted immediately to the BTS.

At T_Paging_Group expiry, if one or more than one paging command messages arecurrently stored:

• the MultiPaging command message is transmitted to the BTS and

T_Paging_Group timer is restarted

• otherwise T_Paging_Group timer is restarted

Hence, all paging requests messages accepted by the BSC filter are all sent to the

BTS which means up to 105 paging command / second.

Note: The value of this T_Paging_Group is set to 200ms and can not be modified

even via the bsc data config tool.




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The Packet paging message, received from the PCU, are sent by the BSC to the BTS

(on the SAPI GSL) whereas the Circuit paging message from MSC are sent to the

BTS by the BSC on the SAPI RSL. Therefore PS and CS pagings are not sent into the

same multipaging message command.

With I multipaging command message the process of combining paging messages

into one multipaging command message is supported by CS paging only.

The restriction is removed with UI multipaging command feature as it allows

combining the packet paging messages before sending them to the BTS.

FEATURE ACTIVATION

The feature is deactivated by default and can be activated thanks to a build on line.

Recommended upgrade steps are the following:

• Upgrade of the BSC without activation of the UI MultiPaging feature (type 4)

• Upgrade of the BTS supported by the BSC

• Activation of the UI Multipaging feature in the BSC (via a build on line)

CAUTION!

In order to identify bad PCM links and fix it, the operator should monitor the quality of

all the PCM links before the feature activation.

As soon as the BSCe3 and the TRXs of BTS are able to manage this feature, the BSC

sends UI MultiPaging Command messages.

The BSC is aware of the BTS capacity for the Circuit Service thanks to the DRX

catalog file and especially the bit 8 (from 0 to 31) of the hardware mask defined as

follow:

• 0: UI MultiPaging Command message for Circuit Service not supported

• 1: UI MultiPaging Command message for Circuit Service supported

As all types of DRX support this feature (except DCU2), there is no modification of the

"display all" feature, in order to know the activation state of this feature.

Note: As this feature is not implemented on BSC12000 and due to upgrade

constraints, then the BTS has to manage the following types of paging messages: I

paging command, I MultiPaging and UI MultiPaging command messages.




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4.13.7 NETWORK MODE OF OPERATION I SUPPORT IN BSS

The Network Mode of Operation 1 (NMO1) takes benefit of the Gs interface to exchange

messages between the MSC and SGSN in order to coordinate the CS and PS paging

management and to optimize some signaling procedures.

Note that Gs interface (between SGSN and MSC) is a pre-requesite before using NMO1.

The feature should be enabled with gprsNetworkModeOperation (bts object). The parameter is

at BTS object but must be consistent at Routing Area level, i.e. activated (or de-activated) in

all cells of a given Routing Area.

PAGING MANAGEMENT

If NMO1 is activated, CS-Paging are managed through Gb interface for any GPRS-attached

MS. ClassB MS may be simultaneously attached to GSM and GPRS services but cannot

simultaneously perform CS and PS transfer.

If the MS is not attached to GPRS services, the CS-Paging procedure is not modified and

done through the A interface.

If the MS is attached to GPRS, the CS-Paging is sent from the MSC to the SGSN (Gs

interface) and then to the PCU (Gb interface):

• If the target mobile is in GMM STANDBY state, the PCU transmits the Paging

message to the BSC on the SAPI RSL. Therefore the BSC has to broadcast

this message on the CCCH of all target cells.

• If the mobile is in GMM READY state, the PCU sends the Paging on the

PACCH of the TBF or on the CCCH of the cell if there is not an established

TBF for the target mobile. In case Paging is sent on PACCH, the PCU repeats

the paging message 3 times (1 emission + 3 repetitions), with a delay

between 2 occurrences equal to 480 ms. This enhances the probability of

success of the Paging procedure.

The 3 different cases (MS not GPRS-attached, MS in GPRS STANDY state and MS in GPRS

READY state) are illustrated below.

Note that the load of some interfaces is impacted by NMO1 activation:

• less paging on A interface less load on A interface.

• more paging on AGPRS interface more load on AGPRS LAPD TS.




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COMBINED SIGNALING PROCEDURES

Two procedures are combined when using NMO1:

• Combined GSM / GPRS Attach

• Combined LA / RA update.

Each procedure is performed with a single access on packet channels. This is transparent for

the PCU, which manages it as usual without any particular action. The SGSN then informs the

MSC through the Gs inteface.

The following gains are expected:

• decrease of SDCCH occupancy

• less load on A and Abis interfaces

• less load on BSC

• faster cell reselection between 2 LA.

Notes:

• As the combined procedures are performed on packet channels, it is critical to

protect the access to GPRS service and thus set minNbrGprsTs > 0

• There is a LAPD impact on Agprs interface due to the addition of cs_paging

messages for the data attached mobiles.

MSC/VLR

BSC

BTSBTS BTS BTS

SGSN

PCU

MSC/VLR

BSC

BTSBTS BTS BTS

SGSN

PCU

MSC/VLR

BSC

BTSBTS BTS BTS

SGSN

PCU

MS not attached to

GPRS services

Paging procedure not

modified

MS attached to

GPRS services &

standby state

MS attached to

GPRS services &

ready state

BSC broadcasts paging

on CCCH

Paging on:

• PACCH if TBF established

• CCCH if no TBF established

MSC/VLR

BSC

BTSBTS BTS BTS

SGSN

PCU

MSC/VLR

BSC

BTSBTS BTS BTS

SGSN

PCU

MSC/VLR

BSC

BTSBTS BTS BTS

SGSN

PCU

MS not attached to

GPRS services

Paging procedure not

modified

MS attached to

GPRS services &

standby state

MS attached to

GPRS services &

ready state

BSC broadcasts paging

on CCCH

Paging on:

• PACCH if TBF established

• CCCH if no TBF established




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4.13.8 BSS CS PAGING COORDINATION

For details please refer to the functional note ([R57] and also to the aPUG document ([A1]).

PRINCIPLE

When NMO II is used, the network sends all paging messages on the PCH paging channel

even if the mobile has been assigned a packet data channel, which might require the MS to

leave the packet channel to monitoring the occurrence of paging messages. Compared to

NMO II, the BSS CS Paging Coordination is an additional mechanism for handling CS paging.

It provides an NMO I-like mechanism (BSS CS Paging Coordination) without involving the

packet core and Gs interface. This maximizes the end-user availability for receiving CS calls

and the related revenues.

While the network is running with NMO II, the BSC sends all CS paging messages received on A interface both to the BTS and, with BSS CS Paging Coordination feature activated, to the

PCU as well. The PCU then checks whether the corresponding MS is engaged in a PS

session, by checking the IMSI. If so, the PCU sends the CS paging message to the mobile on

PACCH channel.

BSS CS PAGING COORDINATION MECHANISM

ACTIVATION PARAMETER

The activation parameter of this feature is bssPagingCoordination (class 3, bts objet).If the network is running in Network Mode of Operation II and if BSC and PCUSN support the

BSS CS Paging Coordination feature, the bssPagingCoordination parameter serves to set

BSS_PAGING_COORDINATION bit in GPRS Cell Options to “1” to enable the BSS CS

Paging Coordination mechanism for all GPRS/EDGE mobiles.

Therefore, the behaviour of class B mobiles (from Release 97) is modified when enabling this

new BSS CS Paging Coordination in the network, provided that both the BSC and the PCUSN

support the feature.

SI13 UPDATE

The BSC updates the System Information 13 message to indicate the activation/deactivation

of the feature and sends PCU BROADCAST INFO MODIFY to provide the updated content of

the SI13 to the PCU.

DETAILED PAGING COORDINATION MECHANISM




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If the network is running in Network Mode of Operation II, when the BSC receives a CS paging

from A interface :

• the BSC broadcasts this paging message in the target cells (as it has always done so

far), regardless of bssPagingCoordination parameter value,

• and, if bssPagingCoordination is enabled on at least one cell of the area, the BSC

sends the paging message in a single BSC CS Paging message to the PCU (even if

the CS paging addressee is a list of cells) on one of the available Agprs PCM (with a

round-robin mechanism to spread the CS paging load on all Agprs PCMs connectedto this BSC).

When a PCU element receives a CS paging on its Agprs PCM, it broadcasts this message to

all PCU elements connected to the same BSC that issued the CS paging message. Each PCU

element then checks whether the IMSI value included in the BSC CS Paging message

corresponds to one of the existing MS context (i.e. a mobile that is known as currently having

an established TBF). In this case :

• if the bssPagingCoordination parameter is set to “enable BSS paging coordination” in

the corresponding cell, the PCU sends the CS paging on PACCH using the

mechanism used for Network mode of Operation I (see §4.13.7).

• otherwise the paging is discarded.

CS pages onCCCH

MSC/VLRSGSN

PCUSN

BS

C

BTS

BTS BTS

BTS

BTS

CS Pages

CS Pages

broadcast on CCCH

All CS pages

are transferred tothe PCUSN

SPM

SPMSPM

SPM

SPMSPM

SPM

PCUSN

SPM has

found that aTBF is alive

for this MS

CS pages

on PACCH

TBF alive

No TBF alive




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4.14. FREQUENCY HOPPING

4.14.1 FREQUENCY HOPPING PRINCIPLES

Basically, Frequency Hopping aims at spreading the spectrum of the signal to minimise the

impact of potential interferers. Frequency Hopping consists in changing the frequency used by

a channel at regular intervals.

In GSM, the transmission frequency remains the same during the transmission of a whole

burst. Thus, it is possible to have different frequencies on each burst of a frame. The radio

interface of GSM uses then slow Frequency Hopping.

According to the type of coupler used in the BTS, two (2) main types of Frequency Hopping

mechanism can be used:

• Synthesised mode for Hybrid couplers with duplexers: hopping time slots can

hop on a large band of frequencies.

• Baseband mode using Cavity couplers with duplexers: hopping time slots can

hop on a set of frequencies limited by the number of TRXs (only available with

S4000 BTS).

Note: using frequency hopping allows to adapt and maximise the frequency re-use pattern

efficiency by maximising the capacity in term of offered Erlang/Mhz/km2. The pattern to use

will depend on the available frequency band and the traffic requirement.

It is possible (and recommended) to mix different frequency re-use technique, as 4X12 for

BCCH and 1X3 or 1X1 for TCH. Indeed, a traditional 4X12 reuse pattern is appropriate to awide spectrum allocation as for BCCH frequency (only one frequency per cell is needed).

However, in order to increase the number of TRX per cell with a given frequency band, while

keeping a low interference level, the only solution is to use more restricting reuse pattern, as

1X1 or 1X3.

See also chapter General Rules For Synthesised Frequency Hopping.




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4.14.2 MAIN BENEFITS OF FREQUENCY HOPPING

• the higher the number of frequencies in the hopping law, the smaller the

Fading margin taken into account in the link budget (due to Rayleigh fading).

• the smaller the mobile speed and the higher the number of frequencies, the

higher the benefit of the frequency hopping.

• the higher the number of frequencies in the hopping law, the narrower the

Rxqual distribution. However Rxqual mean remains the same (see figure

below). Hence the Frequency Hopping eliminates the number of bad Rxqualsamples but it also reduces the number of good Rxqual ones.

RXLEV cdf versus SFH

FADING MARGIN (dB)

%

1

10

100

-2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

1 freq

2 freq

4 freq

8 freq

2

48

RXLEV cdf versus SFH

FADING MARGIN (dB)

%

1

10

100

-2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

1 freq

2 freq

4 freq

8 freq

2

48

Frame Erasure Rate versus SFH at –104 dBm (DCS)

NUMBER OF FREQUENCIES FOR HOPPING

F E R ( % )

0.00

2.00

4.00

6.00

8.00

10.00

12.00

1 2 3 4 5 6 7 8

0.5 km/h

1.5 km/h

2.5 km/h

5 km/h25 km/h

0.5

1.5

2.5

5

25

Frame Erasure Rate versus SFH at –104 dBm (DCS)

NUMBER OF FREQUENCIES FOR HOPPING

F E R ( % )

0.00

2.00

4.00

6.00

8.00

10.00

12.00

1 2 3 4 5 6 7 8

0.5 km/h

1.5 km/h

2.5 km/h

5 km/h25 km/h

0.5

1.5

2.5

5

25




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• Increase resistance to Rayleigh fading:

re-centred RxQual distribution for slow moving mobilesbetter stability of the received signal level (smoothing effect)

completion of diversity task on uplink and full benefit on downlink

high improvement for areas of weaker signal strength (inside buildings and

on street level)

• Resistance to interference

spread of interference over all RF spectrum

spread of interference over time

highly loaded sites benefit from lower load on adjacent sites

more efficient error correction gain from digital processing

cdf RxQual with SFH, at 0.5 km/h, -104 dBm (DCS)

BER %

0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10

1 freq4 freq8 freq

16 freq4 816

cdf RxQual with SFH, at 0.5 km/h, -104 dBm (DCS)

BER %

0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10

1 freq4 freq8 freq

16 freq4 816




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4.14.3 SYNTHESISED FREQUENCY HOPPING

Using synthesised frequency hopping, each TX is associated to one FP (TDMA) and can

transmit on all the frequencies. It is used with hybrid coupling systems then more frequenciesthan TRXs can be used.

The main issue is to ensure that the frequency BCCH is transmitted all the time (on all the TS

of the TDMA) at a constant power even if there is no call to transmit (no voice or data burst).

This is done by a specific configuration which consists in dedicating a TRX to the BCCH

frequency (so the TDMA called BCCH does not hop).

Generally, the number of frequencies is greater than the number of TRX in order to have the

smallest Fading margin in the link budget.

The TDMA configurations in case of synthesised frequency hopping are defined as follows:

• F1 is the BCCH frequency.

• the other two TDMA of the cell have the same MA. HSN and MAIO can be

different.

MA frequency list

TDMA1TX1

TX2

TX3

TX4

BCCH Freq

TDMA3

TDMA2

TDMA4

MAIOMA frequency list

TDMA1TX1

TX2

TX3

TX4

BCCH Freq

TDMA3

TDMA2

TDMA4

MAIO




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4.14.4 BASEBAND FREQUENCY HOPPING

PRINCIPLE

Using baseband frequency hopping, each TX is dedicated to one frequency and is connected

to all the Frame Processor (TDMA) via the FH bus. It is used with cavity coupling system. It

uses exactly the same number of frequencies as TRXs.

The filling is done by the FP according to the configuration of the TDMA (all the parameters for

the frequency hopping are static and not per call basis; so even if there is no call the FP

knows if it has to transmit on the BCCH frequency).

Moreover the TX can have a carrier filling functionality which is not useful for the BCCH

frequency (Carrier filling is already done by the FP) but which can be used in case of other

frequencies carrier filling with the use of a specific BCF load.

For a given cell with the previous configuration (4 TRX), one Mobile Allocation should bedefined:

• MA0 contains all the frequencies except the BCCH frequency (3

frequencies in the exemple).

The baseband frequency hopping configuration is the following:

• hopping on TCH, no hopping on BCCH

FP1 TX1

FP2

FP3

FP4

TX2

TX3

TX4

BCCH Freq

Filling burst when there is no information

to transmit on the BCCH frequency.

If filling is needed on other frequencies,

it is managed by the TXs.

FP1FP1 TX1

FP2FP2

FP3FP3

FP4FP4

TX2

TX3

TX4

BCCH Freq

Filling burst when there is no information

to transmit on the BCCH frequency.

If filling is needed on other frequencies,

it is managed by the TXs.




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TS 0 1 2 3 4 5 6 7

TDMA 0 F1 F1 F1 F1 F1 F1 F1 F1 MAIO=0

TDMA 1 MA0 MA0 MA0 MA0 MA0 MA0 MA0 MA0 MAIO=1



• MA: Mobile Allocation (list of hopping frequencies for a TRX)

• MAIO: Mobile Allocation Index Offset between 0 and (Nb of Freq in MA -

1).

• F1: BCCH frequency

CAUTION!

It is not recommended to hop on BCCH frequency when using baseband frequency hopping,

because it can lead to some troubles when downlink DTX or downlink power control are

enabled.

RECONFIGURATION PROCEDURE

This procedure is not applicable to BTS that use hybrid coupling.

With the baseband frequency hopping mechanism (used only by BTS that have cavity

couplers), it is possible to reconfigure the frequencies in certain cases. In case of equipment

failure/recovery within a TRX, the BSC starts the reconfiguration process for a Radio Cell

which supports frequency hopping and uses the Frequency Management GSM function.

This function is supported by the TRX and allows the BSC to configure or to reset a frequency

on a TX which is identified by the TEI of the corresponding TRX. The loss of one TX implies

the loss of one frequency (which is not the BCCH) and of one TDMA (the one defined with the

lowest priority) if no redundant TRX.

Two symmetric mechanisms are managed by the BSC to handle the automatic frequency

reconfiguration in the case of frequency hopping cavity coupling BTS:

• loss of a frequency

the cell is stopped and restarted with new set of frequencies. This may lead

to release the calls if there is more live TX than btsThresholdHopReconf

• recovery of all frequencies

an automatic reconfiguration is triggered by the BSC when all the

frequencies are recovered. This may lead to release the calls

There will be a reconfiguration if the flag bscHopReconfUse is set to “true” (defined at BSC

level) and if there are more frequencies than the threshold btsThresholdHopReconf (defined at

BTS level). Otherwise the cell is badly configured.

When a end of fault occurs if the flag btsHopReconfRestart is set to “true” and if there are

more frequencies than the threshold (btsThresholdHopReconf), there is a complete cell

reconfiguration.




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4.14.5 AD-HOC FREQUENCY PLAN

The Ad-Hoc frequency hopping does not reproduce a pattern all over the network. Frequency

planning is done (HSN, MAIO, MA lists) according to the interference matrix. The particularityis that the number of hopping TRX = the number of hopping frequencies in most of the cases.

A frequency plan optimizes frequency hopping list of each sector in order to reduce the

interferences. The length of the frequency hopping list is variable (it should be at least equal to

the number of TRx on the sector).

For ad-hoc frequency planning, an interference matrix or a very intense and accurate drive

tests campaign is needed. A frequency planing tool can also be used.

For each method the principle is the same: take into account DL BCCH and HO interactions

between cells. The frequencies on the list are planned intelligently in order to avoid collision

with the neighboring cells, allocating same frequencies on the hopping list to cells which are

far in distance or that the interaction between them is the minimum as possible.

There is a reduction on the number of frequencies on the frequency hoping list. It is

recommended to space the maximum as possible (at least 3 channels) the frequencies used

in the same frequency list to maximize frequency hopping gain (fading reduction)

Every sector of one site has a different HSN in order to minimize co-channel or adjacent

collisions.

The main drawback is the cost to maintain the plan since regularly it is recommended to

review the plan in order to optimize its performances.

Ad-hoc should be considered as a spectral efficiency feature in a constraining bad condition

assuming the cost associated. In case of non frequency band constraining conditions, 1x1 has

shown a great cost-performance trade-off and is worth to use in the case of a fast growing

network in order to minimize operational impacts.

In summary Ad-Hoc frequency plan allows good performances if the calculation method is

very precise (either Interference matrix, drive tests or frequency planning tool) and number ofhopping frequencies per TDMA is sufficicent (at least MA list ≥ 4 frequencies)

TDMA1 TX1

TX2

TX3

TX4

BCCH Freq

TDMA3

TDMA2

TDMA4

MA frequency list: n frequencies for n TRX

TDMA1 TX1

TX2

TX3

TX4

BCCH Freq

TDMA3

TDMA2

TDMA4

MA frequency list: n frequencies for n TRX




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4.15. BSC OVERLOAD MANAGEMENT MECHANISMS

The aim of such a feature is to avoid BSC restart or crash because of overload conditions.

Without defense mechanism, an overload of one of the BSC boards will imply a suicide of the

active chain, a switch to the passive chain and at last a suicide of the new active chain. This

implies a suppression of all the communications and an interruption of service.

For further details on this feature please refer to BSS Engineering Rules in chapter Reference

Documents

4.15.1 BSC3000 OVERLOAD MANAGEMENT

The Overload software manages the board load and the global load of the system so as to

avoid the crash in case of overload. On the BSC sub-system an overload situation is mainly

due to the traffic management which is computed on the TMU module. The overload software

uses system indicators to calculate overload levels that allow applications to decrease the load

level.

BSC3000 DIMENSIONING RULES

The BSC is responsible for accepting or rejecting sites creation or reparenting in order to

ensure that the hardware capacity is sufficient to handle the traffic.

The maximum dimensioning of a BSC 3000 is 3000 or 4000 Erlang, 500 Sites, 600 Cells,

1000 or 1500 TRX, 16 SS7 links, 567 LAPD links. A good dimensioning lead to the following

relations:

Carried Traffic ≤ BSC hardware capacity (number of TMU)

Offered Traffic ≤ BSC hardware capacity (number of TMU)

CARRIED TRAFFIC

The carried traffic (or real traffic) is the number of simultaneous voice communication a BSC

handles at the busy hour. The carried traffic is given by the customer for an area or can be

observed with monitoring. It is necessary to consider a margin carried traffic for a lot of

reasons (GPRS traffic is increasing lightly the load on the TMU, Load balancing algorithm

shares fairly the load between TMU, The operator wants to be able to absorb additional traffic

in case of special Event).

As a consequence it is recommanded to use a margin of about 20-25 % when considering the

carried traffic.

Moreover AMR handset penetration should be considered if half rate vocoder is used on a

network since it increases offered capacity on radio sites.




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LIST OF OPERATIONS TO BE FILTERED

• Overload level 1: filtering 33,33% requests of the following messages:

Paging request

Channel request with cause different from “Emergency call” All first layer 3 messages with cause different from emergency call

Handover for traffic reason

Directed retry

• Overload level 2: filtering 66,66% requestsof the messages described above

• Overload level 3: no new traffic is accepted by filtering all previous and

following messages

All first layer 3 messages

All handover indication

All handover requests

PARAMETERS

No specific new counters or configuration parameters are introduced with this feature.

4.15.2 LOAD BALANCING

The Load Balancing is a mechanism that allows a distribution as balanced as possible (from

the traffic weight point of view) of the Cell Groups (CG) among the existing TMUs (See

chapter BSC Boards Management) during the initialization phase. It also allows a

redistribution of the CG on the TMUs (if all the CG are duplex), without disturbing theestablished calls when:

• A TMU module fails or comes into operation (for hardware or operator

reasons)

• An imbalance of the TMU loads is detected by the BSC (on online operations

such as new TMU board, new BTS, or new TRX). In this case, the load

balancing can be manually started.

For further details on this feature please refer to the corresponding chapter in the BSS

Engineering Rules (chapter Reference Documents).

4.15.3 EVOLUTION OF LOAD BALANCING

Some evolutions are introduced in the Cell Group Management and Load Balancing

algorithms used by the BSCe3. These evolutions are made in order to take into account the

introduction of new TMU boards (TMU2), to better introduce new big site configurations.

MAIN EVOLUTIONS

Global dimensioning constraints for the BSC remain unchanged: the BSC capacity is limited

by the following maximum number of managed objects:

• Maximum of 1000 TRX or 1500 per BSC

• Maximum of 600 Cells per BSC




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4.16. CABINET OUTPUT POWER SETTING

This section aims at describing the way to determine the output power of a BTS knowing its

coupling and its associated parameter setting. As described in following figure, two OMCparameters are involved: bsTxPwrMax (powerControl object) and attenuation

(btsSiteManager object).

4.16.1 CABINET POWER DESCRIPTION

There are three steps in the cabinet output power evaluation.

Txtranslation

table

Txtranslation

table

Coupling

system

Coupling

system

OR

SUM

OMC attenuation

(since V9)

DLUattenuation

(until V8)

bsTxPwrMaxPc Pr Ps

Pc: bsTxPwrMax + DLU/OMC attenuation

Pr: given by a translation table

Ps: Cabinet output power

Txtranslation

table

Txtranslation

table

Coupling

system

Coupling

system

OR

SUM

OMC attenuation

(since V9)

DLUattenuation

(until V8)

bsTxPwrMaxPc Pr Ps

Pc: bsTxPwrMax + DLU/OMC attenuation

Pr: given by a translation table

Ps: Cabinet output power




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4.16.2 PR COMPUTATION

According to bsTxPwrMax, the coupling system and the product family (S8000/S12000) Pr

can be defined

For more details on the Pmax per products, please refer to the Engineering Rules (ref. [R47]

to ref. [R56]).

4.16.3 PS COMPUTATION

Then, the effective cabinet output power is:

Ps = Pr - cablesLoss - couplingLoss

Pr is derived from Pc (where Pc = bsTxPwrMax + OMCattenuation or DLU attenuation) based

on the translation table (§ 4.13.2). Pr can only be equivalent to Pmax in case when the

operator has chosen the maximum value for bsTxPwrMax for a given coupling system.

POWER AMPLIFIER 30W

The nominal output power output for PA is 44.8 dBm (+/- 0.5dBm). This nominal output is the

same for all frequencies.

HIGH POWER EDGE POWER AMPLIFIER (HEPA)

The nominal power output for HePA depends on the frequencies and on the product. Please

note that not all product support HePA for all the frequency bands.

For more details on HePA output power as a function of the product and the frequency band,

please refer to the appropriate Engineering rules document ([R47] to [R56])..

COUPLING SYSTEM

To know the input power, it is important to factor in the system coupling losses. Please refer to

the appropriate Engineering rules document ([R47] to [R56]).

CABLE LOSS

For the values of the losses depending on the BTS configuration and frequency band, please

refer to the appropriate Engineering rules document ([R47] to [R56]).




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4.17. SYSTEM INFORMATION MESSAGES RELATED FEATURES

4.17.1 DUAL BAND HANDLING

The purpose of this feature is to allow an operator with licenses in several frequency bands to

support the use of multiband mobile stations in all its bands. In addition, it also allows the

operator to support the use of single band mobile stations in each band of the license. The

specification indicates that GSM900 and GSM1800 frequency bands can be combined. No

frequency band is treated as the primary band. However, parameter setting can help

multiband MS to give a higher priority to one of the bands.

CAUTION!

It has been experimented that with some mobile brands a delay in the other band neighbor

cells reports occurs, i.e. a minimum time is necessary for those mobiles to sendmeasurements from neighbors transmitting of the other band to the current cell.

MULTIBAND MOBILE STATION

A multiband mobile station is a mobile station which:

• supports more than one band

• has the functionality to perform handover, directed retry, channel assignment,

cell selection and cell reselection between the different bands in which it can

operate (within the PLMN)

• has the functionality to make PLMN selection in the different bands in whichcan it operate

• has 2 receivers, one specific to each band

• has 2 transmitters, one specific to each band

MODIFIED SYS INFO 3

Two new fields have been added to SYS INFO 3:

EARLY_CLASSMARK_SENDING_CONTROL

It indicates if multiband MS is authorized to send the early Classmark Change message to theBSC via the BTS. This allows the MSC to receive as soon as possible the multiband

information and to pass it to the target BSC. It will speed up call set-ups and allows to perform

Handover and directed retry when needed. The Classmark Change indicates the frequency

bands supported by the MS and MS power classes to perform HO procedures in the best

conditions.

The corresponding parameter is the class 3 attribute early classmark sending belonging to bts

objects. If it is set to “enabled”, the Classmark_Change message is sent just after the SABM

and UA frames exchange on the Immediate_Assignment procedure. This message makes

interband handover procedures possible. Moreover this parameter allows the mobile to send

its capacity downlink Advanced Receiver performance. That helps to have SAIC mobilepenetration




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In single band networks, early classmark sending will be set to “disabled”.

Note: indeed monoband network may forbid a dual band mobile to use the Early Classmark

sending procedure in order to prevent phase 2 mobiles to send useless information to the

network, and to cope with any potential problems with this feature in the mobiles.

SYS_INFO_2TER_INDICATOR

It is used to inform multiband MS that SYS INFO 2ter information is available.

NEW SYS INFO MESSAGES

The neighbouring cell lists for handover and cell reselection are broadcast towards multiband

and single band mobile stations. The frequencies of neighbouring cells in other frequency

bands than the current cell will be carried by new SYS INFO messages:

• SYS INFO 2ter for reselection neighbours.• SYS INFO 5ter for handover neighbours.

A single band mobile station will only use frequencies from SYS INFO 2 and 5 and if

necessary, 2bis and 5bis for reselection and handover purposes, i.e. frequencies from the

frequency band it supports. The BSC selects neighbour cells from the other band out of the

neighbour list and sends them in SYS INFO 2ter and 5ter (see table below).

Sys info 2

Sys info 5

Sys info 2bis

Sys info 5bis

Sys info 2ter

Sys info 5ter

GSM900 cell GSM900 nei list - GSM1800 nei list

GSM 1800 cell GSM1800 nei list GSM1800 nei list GSM900 nei list

NEIGHBOUR CELL LIST IN SYS INFO

The new SYS INFO 2ter and 5ter messages carry parameters which are needed by multiband

mobile stations to perform respectively cell reselection (2ter) and handover (5ter) towards cell

from another band:

• Multiband Reporting: indicates to multiband MS the minimum number of cells

to report in their measurement report outside the current frequency band. Its

value is equal to the Multiband reporting parameter in the SYS INFO 5ter

message.• Neighbouring Cells List: coding of the frequencies of neighbouring cells.

CAUTION!

Some single band mobiles are disturbed by the receipt of SYS INFO 5ter. They react by

sending an RR status message, that can load the BSC. To avoid this, the sending of these

messages is controlled by the BTS. On the opposite, single band mobile stations are not

disturbed by 2ter messages because they ignore them.

No field called ‘Sys_Info_5ter_Indicator’ exists. To know if 5ter messages are sent, SACCH

filling messages are used.

The parameter cellBarQualify is not used by some dual band MS in selection and reselectionalgorithms.




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MULTIBAND REPORTING

Multiband mobile stations report cells from different frequency bands according to Multiband

Reporting parameter (corresponding to class 3 attribute ‘multi band reporting’ of bts objects)

broadcast in SYS INFO messages:

• the six strongest cells: default value. The multiband MS reports the six

strongest allowed cells regardless of the frequency band.

• 1, 2, 3: the multiband MS reports the strongest or the two, three strongest

allowed cells outside the current frequency band. The remaining space in the

report is used to give information about cells in the current frequency band. If

there are still some remaining positions (not enough neighbours in the current

frequency band), these positions are used to report cells outside the current

frequency band.

CAUTION!

A maximum of six cells will be reported. Only this maximum of 6 ”best” cells will be

transmitted to the BSC by the L1M in a Handover_Indication message .

OHER PROCEDURES

The handling of multiband MS did not need specific changes in L1M. Main changes are on MS

side. However, main procedures can be reviewed with the differences that occur in V10.

• PLMN selection: a single band MS only selects a PLMN from its frequency

band. A multiband MS can select PLMNs of both bands.

• Cell selection & reselection: a single band MS only selects or re-selects cells

from its frequency band. A multiband MS can select or re-select cells of both

bands. Priority can be given to one band (see chapter Selection, Reselection

Algorithms).

• Handovers: a new attribute is introduced in both adjacentCellReselection and

adjacentCellHandover objects. Its name is standardIndicator Adjc and tells the

type of network where the neighboring cell operates (“gsm” or “dcs” or

“gsmdcs” or “dcsgsm”). A single band MS only performs handovers towards

cells from its frequency band. A multiband MS can perform handovers

towards cells of both bands if classmark 3 is supported on NSS side.

If local mode directed retry is chosen, as it is performed towards a specific neighbour, one

type of single band MS (the one which does not support the frequency band of adjacent cell

umbrella ref ) will not use this feature.

For multiband MS, formulas like PBGT or thresholds are the same as single band ones, their

power class is replaced according to the band of the cell they are in (se chapter General

formulas).




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range 0 to 7. This number is called TC. The 3GPP specifications define in which BCCH repeat

period (TC value) a specific SYS INFO message can be sent.

SI2Ter, SI13 and SI2quater can be sent when TC=4.

This means that:

• if 1 of SI2Ter, SI13 and SI2Quater messages has to be sent, it will be sent

every 1.88 seconds.

• if 2 of SI2Ter, SI13 and SI2Quater messages has to be sent, each will be sent

every 3.76 seconds.

• if all of SI2Ter, SI13 and SI2Quater messages has to be sent, each will be

sent every 5.64 seconds.

Redirection procedure duration is directly linked to the time the MS needs to read system

information messages.

On the contrary, the sending of system information on extended BCCH increase load on

AGCH/PCH channel.

BENEFITS

Customers are facing MS issues:

• Devices being unable to read SI13 messages when these are sent on the

Extended BCCH. The impact of the failure to read this message was that the

device is partially or completely unable to connect to GPRS services.

• Devices seeing valid SI messages containing 3G NCells (SI2Quater) as

“corrupted” when sent on the Normal BCCH; continued reception of these

messages resulted in the device rebooting or failing to set up CS calls.

So if customers don’t wish to recall affected MS the feature allows to modify the allocation of

SI2Quater and SI13 messages

SI2Quater and SI13 on Ext BCCH allow as well speeding up 3G toward 2G cell reselection

(see chapter Mobility 2G - 3G Reselection).

The drawback is a PCH / AGCH capacity lost.

CAUTION!

When this feature is enabled, e.g. if SI2Quater and/or SI13 on extended BCCH features are

activated, the parameter noOfBlocksForAccessGrant has to be greater than 0.




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4.17.3 SUMMARY OF SYSINFO SCHEDULING

For each multi-frame, the BCCH block is used to transmit a BCCH system information. TC

defines the index of the multiframe in which the Sysinfo message is sent by the network. The

broadcast cycle is 8 multiframes therefore the TC index ranges from TC = 0 to TC = 7.

In the absence of option SYSINFO messages, the basic cycle is :

SYSINFO 1, SYSINFO 2, SYSINFO 3, SYSINFO 4, SYSINFO 1, SYSINFO 2, SYSINFO 3,

SYSINFO 4.

TC5 may be preempted by the optional SYSINFO 2x that has the highest priority, where 2bis

priority > 2ter priority > 2quater priority. TC4 is shared by remaining optional SYSINFO

messages one after the other in the following order : SYSINFO 2ter, SYSINFO 2quater and

SYSINFO 13.

Optional SYSINFO tobroadcast

TC=0 TC=1 TC=2 TC=3 TC=4 TC=5 TC=6 TC=7

None (Si n°) 1 (SI n°) 2 (SI n°) 3 (SI n°) 4 (SI n°) 1 (SI n°) 2 (SI n°) 3 (SI n°) 4

2bis only or 2ter only or2quater only

1 2 3 4 12bis or2ter or2quater

3 4

13 only 1 2 3 4 13 2 3 4

2bis & (2ter or 2quater or13)

1 2 3 42ter or2quateror 13

2bis 3 4

2ter & (2quater or 13) 1 2 3 42quateror 13

2ter 3 4

2quater & 13 1 2 3 4 13 2quater 3 4

1 2 3 4 2ter 2bis 3 42bis & 2ter & (2quater or13) 1 2 3 4

2quateror 13

2bis 3 4

1 2 3 4 2quater 2bis 3 42bis & 2quater & 13

1 2 3 4 13 2bis 3 4

1 2 3 4 2quater 2ter 3 42ter & 2quater & 13

1 2 3 4 13 2ter 3 4

1 2 3 4 2ter 2bis 3 4

1 2 3 4 2quater 2bis 3 42bis & 2ter & 2quater &13

1 2 3 4 13 2bis 3 4




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4.18. INTERFERENCE CANCELLATION

Note : to activate interference cancellation feature, it is necessary to have receive diversity

enabled. Interference cancellation is a very important feature in a mobile network, especiallywhen capacity is a critical issue and aggressive frequency reuse schemes are applied to

maximize it. Experience has shown gains with an adhoc frequency plan. Preliminary studies

had indicated that in a 1X3 reuse frequency pattern network, capacity could be limited by

uplink interferers. In general, even if capacity is not limited by uplink interferers, it is essential

to mitigate their effect for quality improvement. Moreover it has been experienced that even if

capacity is not UL limited, Interference Cancellation ensures improvements on data

performance in UL, vocal quality in UL and measurement reports in UL, which improve

mobility management. This results in a descreasing number of radio drops (study done with

half MS quite UL weak, half MS quite DL weak).

A BTS-based interference cancellation algorithm is of great interest. Nortel has designed aproprietary signal processing scheme aimed at cancelling the interferers. It works on the Base

Stations equipped with all DRX S8K/S12K and with BTS18000. The effect of the feature

depends on diversity: on a site without diversity, the feature Interference Cancelation will have

no benefit. The algorithm works as well with or without frequency hopping and it can remove

any kind of interferer that has some spatial or temporal coherence (co-channel, adjacent

channel, CDMA signal leaking in the PCS band, TV transmitter, etc..). It can be viewed as a

digital beam-forming technique in which a null of the radiation pattern is pointed towards the

interferer.

The algorithm is based on the use of the Maximum Ratio Combining diversity technique and

the midamble in the GSM burst that is used to gain some indication of the channel

characteristics, and hence an estimate of the noise present. This noise is approximately made

up of interference and thermal-noise. The midamble is a known sequence of bits, which

undergoes changes after propagation. The interference estimation is necessarily biaised since

it is estimated on a short period of time (22 Tsymbol compared to the 148 Tsymbol) and the

interference cancellation in the absence of interference will result in decreasing the SNR ratio.

To avoid this problem, a parameter ρ is introduced.

8 interfering MS ’s

on the 8 TS ’s of F0

MS driving away

from serving BS

BS#2

BS#1call drop:

too high C/I

8 interfering MS ’s

on the 8 TS ’s of F0

MS driving away

from serving BS

BS#2

BS#1call drop:

too high C/I




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4.19. EXTENDED CCCH

This feature consists in the implementation of the extended CCCH feature The need of this

feature has been identified in some configuration where only one CCCH is not sufficient, dueto a high rate of paging and immediate assignment.

4.19.1 CUSTOMER/SERVICE PROVIDER BENEFITS

This feature allows increasing the rate of paging and immediate assignment messages related

to a cell and thus:

• Allows managing large location area with up to 16 TRX per cell,

• Gives the ability to manage multi-layers networks

• Allows managing GPRS traffic.

4.19.2 FEATURE FUNCTIONAL DESCRIPTION

You can allow the configuration of extended CCCH on TS 2, 4 and 6 of the BCCH TDMA.

The following CCCH configurations are now available :

CCCH_Conf = 0:

• TS 0 = FCCH+SCH+BCCH+CCCH

CCCH_Conf = 1:

• TS 0 = FCCH+SCH+BCCH+CCCH+SDCCH/4+SACCH/4

CCCH_Conf = 2:


• TS 2 = CCCH

CCCH_Conf = 4:


• TS 2 = CCCH

• TS 4 = CCCH

CCCH_Conf = 6:


• TS 2 = CCCH

• TS 4 = CCCH

• TS 6 = CCCH

Note: By increasing the number of CCCH, we decrease the number of TCH, so it leads to

reduction of the capacity. For example, an O8 with 1 BCCH has a capacity of 48,65 Erlangs

(with 2% of blocking rate); with 4 CCCH its capacity drops to 45,88 Erlangs.

To configuration of a CCCH block on a TS the channelType parameter must be set to “cCH’.

See also chapter SDCCH Dimensioning an TDMA Models.




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4.20. CELLULAR TELEPHONE TEXT MODEM (TTY)

Deaf, hard of hearing, and speech-impaired persons have been using specific Text Telephone

(referred to as TTY in North America) equipment in the fixed network for many years totransmit text and speech through ordinary speech traffic channels.

To answer US FCC requirements, NORTEL release with BSC/TCU 3000 introduction) BSS

includes now the Cellular text Telephone Modem (CTM) solution for reliable transmission of a

Text Telephone conversation via the speech channel of cellular or PSTN networks.

4.20.1 TTY PRINCIPLE

Data transmission methods exist in the wireless services, but for various reasons, a text

telephone transmission method for the speech path is desired. Two reasons are:

• text telephony is acknowledged as a way to contact the emergency services,

and emergency services in wireless networks are so far only defined for

speech calls.

• alternating speech and text in a call is desired, and one simple way to

accomplish that without special service support (like multimedia) is by

alternating the use of the speech channel.

CTM allows reliable transmission of a text telephone conversation alternating with a speech

conversation through the existing speech communication paths in cellular mobile phone

systems. This reliability is achieved by an improved modulation technique, including error

protection, interleaving and synchronization.

The CTM is intended for use in end terminals (on the mobile or fixed side) and within the BSS

network for the adaptation between CTM and existing traditional text telephone standards.

The signal adaptation Baudot CTM is localized in the TCU 3000 in each TRM board.

NORMAL CASE

“SPEECH/DATA INDICATOR” = “SPEECH + CTM”

If an ASSIGNMENT REQUEST or HANDOVER REQUEST message is received from the

MSC with:

• Circuit Identity Code compatible with TRM capability (EFR+CTM)

• “Speech/data indicator” = “Speech + CTM”

• and “permitted speech version identifiers” = EFR

an ASSIGNMENT COMPLETE or HANDOVER COMPLETE message will be sent to the MSC

with Speech Version (Chosen) = EFR.




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“SPEECH/DATA INDICATOR” = “SPEECH”

If an ASSIGNMENT REQUEST or HANDOVER REQUEST message is received from the

MSC with:

• Circuit Identity Code compatible TRM capability (EFR+CTM)

• “Speech/data indicator” = “Speech”


• and unavailable archipelago EFR resource (SPU)

an ASSIGNMENT COMPLETE or HANDOVER COMPLETE message will be sent to the MSC

with Speech Version (Chosen) = EFR.

ABNORMAL CASE

On reception by the BSC of an ASSIGNMENT REQUEST or HANDOVER REQUESTmessage with:

• Circuit Identity Code incompatible with TRM capability (the circuit pool implied

by the CIC information element is incompatible with the channel type

indicated)

• “Speech/data indicator” = “Speech + CTM”


• and unavailable archipelago EFR_CTM resource (SPU)

In a first step an ASSIGNMENT FAILURE or HANDOVER FAILURE message will be sent to

the MSC.

In a second step an ASSIGNMENT COMPLETE or HANDOVER COMPLETE message will be

sent to the MSC with Speech Version (Chosen) = EFR TTY impact

4.20.2 TTY IMPACT

TCU 3000

The TCU 3000 capacity is affected by the CTM implementation according to the configured

archipelagos EFR_CTM number.

Please refer to BSC/TCU 3000 Engineering Rules [R63]




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4.21. SMS-CELL BROADCAST

The objective of this feature is to support new broadcast services as advertising or

information’s with BSC12000 and BSC3000

The goal is to offer an interface for the SMS-CB that allows to send easily the same message

on every cell of a list of BSCs and so that the system can update all the cells in a quicker time.

4.21.1 PRINCIPLE

In the Nortel network’s structure of Cell Broadcast Service a Cell Broadcast Center is

interfaced with the OMC via a non Q3 interface. The OMC act as the SMS-CB manager and

broadcast SMS over all the BSCs placed under its control.

The new requirements concern:

• the broadcast of the same short messages on all the cells which are managed

by an OMC-R or a BSC list.

• the change rate of these short messages: 13 seconds are required;

• The current implementation about the short message broadcast involves

several limitations and OAM constrains which should be raised:

• CBC/OMC-R interface throughput which must be compliant with the user

activity performance.

• OMC-R/BSC interface throughput which must be compliant with the number of

message (TGE) to be processed by the BSC (from 1 up to 2 TGE/sec for all

transactions).

• Heavy OAM constraint to update the data base CBC when network (re)configuration occurs.

Cell

Broadcast

Center

OMC

SMS-CB

manager

BSC

BSC

BS

BS

BS

BS

BS

Cell

Broadcast

Center

OMC

SMS-CB

manager

BSC

BSC

BS

BS

BS

BS

BS




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4.21.2 PERFORMANCES

The following table depicts the number of messages:

CBC / OMC / I/F OMC / BSC / I/F

Messages Old New Old New

Create short message 1 1

Start broadcast (first time) X*Y 1 Y 1

Set short message (continued) 1 1

Stop broadcast (continued) X*Y 0 Y 0

Start broadcast (continued) X*Y 1 Y 1

Stop broadcast (last) X*Y 1 Y 1

Periodic MMI commandsnumber

(1+2*X*Y)*n 2*n

Periodic TGEs number

2*y*n

320*n max or

1200*n max

n

X: BSC number [1:30]

Y: Cell number / BSC12000 [1:160]

X*Y: Cell number / OMC [1:2400]

n: Number of updates of messages

With this solution, SMS-CB has been dimensioned for following capacities:

• 5 messages maximum per cell (broadcast in loop)

• message format: 1 page / 93 characters• broadcast periodicity (30 sec, 1 mn, 2mn, 4 mn, 8 mn or 16 mn), 2 sec (1

message / cell) corresponding to the CBCH maximum capacity

The whole users activity can be:

• on an average: 1 MMI command every 10 sec. for the whole set of users. Or,

1 MMI unitary command every 160 sec. per users, with a maximum of 16

users.

• on a maximum: 1 MMI unitary command every 2 sec. for the whole set users,

during 2 hours maximum. Or 1 MMI unitary command every 32 sec. per users,

during 2 hours maximum, with a maximum of 16 users.

The CBC can be associated to n users among 16 ones: then the number of MMI commands

on the CBC / OMC interface is n every 32 sec.

Every short message modifications involves 2 MMI unitary commands (set short message &

start broadcast) the short message change rate is 32*2n.

Note:

When the OMC-R receives one command for all the cells of one or several BSC, it checks for

each cell if there is a CBCH channel and if the limit of 5 short messages is not exceeded. That

defines a “compliant” cell. It then checks if a threshold S (per BSC) corresponding to a max of

tolerated non compliant cells is reached.




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If the limit of 5 messages is exceeded for one or several cells and if the number of non

compliant cells exceeds the threshold S for one or several BSC, the OMC-R rejects the

command and does not sent the TGEs. The TGEs will not be sent for these BSC(s), but will be

sent for the others. The response (FAILED) to the CBC will report per BSC the non compliant

bts identities (up to the first S bts identities per BSC).

If the number of non compliant cells does not exceed the threshold S for any BSC, the OMC-R

accepts the command and sends the TGEs. The response (SUCCEEDED) to the CBC will

report per BSC the non compliant bts identities (up to S bts identities per BSC).

CBCH CHANNEL RECOMMENDATION

On the air interface the CBCH channel takes 4 TS bursts (4*0.577 ms) on one 51 multiframe.

The CBCH channel takes the place of one SDCCH channel.

The SDCCH channel can be mapped on two different ways on TDMA: with BCCH combined

(SDCCH/4) or on one reserved TS for SDCCH (SDCCH/8). Thus it is the same thing for

CBCH.

The CBCH is not using the radio resources of the CCCH. It is using the radio resources of one

SDCCH channel. The activation and the use of the SMS-CB will not impact the load on the

CCCH.

The activation of the CBCH will take 1 SDCCH channel and so will increase the SD

congestion. After the activation of the CBCH one needs to follow the SDCCH congestion and

maybe if necessary on some cells to increase the number of SDCCH channels.

Once defined on the cell the CBCH channel can only be used to send SMS-CB. Thus the

quantity of SMS-CB sent will not impact the load of the radio channels other than the CBCH.

Throughput calculation:

The CBCH (idem to SDCCH) offers 184 bits for a block message (or 4TS).

The corresponding throughput offered by the CBCH carried on 51 multitrame:

Throughput = 184 * 4 / 4.615 ms / 51 = 781 b/s

The limitations described in the FN are:

• SMS of 88 bytes

• 5 messages per cell

• 2 seconds between each message.

This means a throughput of: 88 * 8 * 5 / 2= 1760 b/s, which is more than 2 times the max

throughput of the CBCH channel.




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4.22. AMR - ADAPTATIVE MULTI RATE FR/HR

Nortel BSS has evolved to introduce sophisticated traffic management features dealing with

call quality management and capacity improvements. This feature manages AMR services,which allow high gains and good trade-off between these 2 objectives.

4.22.1 BASICS AND SPECIFIC TERMINOLOGY

In GSM, speech is transmitted on a radio channel (using a speech coder also called source

coder) which has a fixed raw bit rate. The coder delivers speech frames every 20 ms. From

that standpoint, speech quality tends to improve when the source coder bit rate is increased.

If we use a high coder rate, the speech quality will be very good in excellent radio conditions,

as long as speech frames can be decoded properly. But in bad radio conditions, a high

proportion of speech frames will not be decoded, in which case some interpolation will bedone by the decoder, and speech quality actually drops. If we use a low coder rate, speech

quality will be medium or low, but will resist very well to radio channel impairments, due to the

high level of redundancy. Consequently, present techniques like FR or EFR are the result of

compromises between the source coder rate, and the channel coding, within the boundaries of

the raw bit rate of a GSM channel.

AMR techniques are adaptive, and multirate. It means that it allows adapting the compromise

between source coder rate and channel coding/redundancy to actual radio conditions. AMR

may operate in full rate channels, or half rate channels. This is called the “channel type”

(TCH/FR or TCH/HR). Uplink and downlink always apply the same channel type.

Basis of AMR is that within the channel (FR or HR), there is a set of voice coders, along with

associated channel coding, among which the best combination can be selected to maximize

speech quality according to conditions met on the radio link. This is “codec mode adaptation”.

For codec mode adaptation the receiving side performs link quality measurements of the

incoming link. The measurements are processed yielding a Quality Indicator.

For uplink adaptation, the Quality Indicator, as measured in the BTS is compared to certain

thresholds and generates, also considering possible constraints from network control, a Codec

Mode Command (CMC) indicating the codec mode to be used on the uplink. The Codec Mode

Command is then transmitted inband to the mobile side where the incoming speech signal is

encoded in the corresponding codec mode. For downlink adaptation, the DL Mode Request

Generator within the mobile compares the DL Quality indicator with certain thresholds andgenerates a Codec Mode Request (CMR) indicating the preferred codec mode for the

downlink.

Both for uplink and downlink, the presently applied codec mode is transmitted inband as

Codec Mode Indication (CMI) together with the coded speech data. At the decoder, the Codec

Mode Indication is decoded and applied for decoding of the received speech data.




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The following figure provides the AMR data flow from a "CMR, CMC and CMI" point of view

and explains the CMI, CMC and CMR period.

AMR is introduced to choose in real time the repartition between rate of the source vocoder

and channel protection:

• when the transmission is good, a high rate vocoder is chosen and the

number of bits dedicated to the channel protection is low,

• in case of degraded radio conditions, the vocoder rate is decreased, in

order to provide a better channel protection and allow a better voice

quality.

MS BTS

CMI

CMR

CMI

CMR

CMI

CMC

CMI

CMC

20ms

40ms 20ms

40ms

MS BTS

CMI

CMR

CMI

CMR

CMI

CMC

CMI

CMC

20ms

40ms 20ms

40ms

Half Rate

Full Rate

Source coding

Channel codingGlobal throughput = 11,4 kBits/s

Global throughput = 22,8 kBits/s

Half Rate

Full Rate

Source coding

Channel codingGlobal throughput = 11,4 kBits/s

Global throughput = 22,8 kBits/s




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UPLINK REQUESTED CODEC MODE

The BTS computes for each burst the SNR criteria, which provides a good approximation of

C/I. In order to have a smooth variation of these criteria, the BTS applies the following filter:

(SNR)(k) = ß * (SNR)(k) + (1 - ß) * (SMR)(k - 1)

Where ß is equal to:

0.05 in case of FR no frequency hopping channel and slow moving mobile,

0.1 in others cases of FR channels,

0.1 in case of HR no frequency hopping channel and slow moving mobile,

0.2 in others cases of HR channels.

In case of DTX, the BTS cannot evaluate the SNR criteria, thus during the DTX period, the last

value of (SNR)k is taken into account and at the end of the DX period, a time exponential filter

is used in order to increase the weight of the new measures and keep the same period of

filtering. This filtered SNR is compared to a set of thresholds and allows determining the

requested codec mode. If no uplink correct frames is received, the BTS has no way to

evaluate the quality of the downlink path, the BTS decreases the applied downlink codec

mode of one step each 40ms. This procedure is repeated until an uplink frame is correctly

received or the 4k75 codec mode is selected for the downlink path.

CAUTION! Before V16.0 there was a limitation on UL SNR in order to have homogeneousbehavior for AMR calls with every kind of DRX. From now, UL SNR measurements aretruncated at 24dB (48 in 0.5dB) at SDO level, whatever hardware is used. The 48 value givenfrom the BTS corresponds to 24dB and more. This new implementation improves the powercontrol reactivity. That impacts on the AMR metric. Therefore C/I metric values for both AMRand EFR calls cannot be compared.

PARAMETERS

For each mobile, the following set of parameters has to be defined:

• for each link direction (upLink or DownLink), one threshlod per subsequent

codec in the defined Active Codec Set (ACS),

• one hysteresis (the same value is used for each codec mode, but one for FR

and another one for HR channel).

But these parameters are linked to a set of factors, some of them being determined by the

BTS (frequency hopping, MS speed), others being network dependent (environment profile…).

The following table is implemented in the BSS:




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According to the network configuration, and for each combination of codec mode and link

direction, the operator selects the appropriate thresholds by using the parametersamrUlFrAdaptationSet, amrUlHrAdaptationSet, amrDlFrAdaptationSet, amrDlHrAdaptationSet

(or the single parameter amrAdaptationSet before V15.1.1). These parameters allow to

choose between 3 sets of pre-defined tables (optimistic, pessimistic and typical settings) plus

one set of tables which is user-defined The BSS using the TS configuration and the MS speed

applies the appropriate column for the uplink path.

As specifed in the GERAN recommendations (05.09) the mobile shall use the downlink

thresholds provided by the BSS defined for a reference environement: Typical Urban 3 km/h

with ideal frequency hopping at 900 MHz. The MS shall then apply a normalization factor to

normalize with respect to different channel types. The normalization factor is mobile

dependant.

See also chapter AMR Field Feedback for further informations on the codec adaptation table.

RATSCCH MANAGEMENT

This new channel is used in order to change the set of codec modes (see "L1m" section), and

has the following main characteristics:

• frame stealing (1 speech frame for a FR channel, 2 speech frames for a HR

channel),• priority of RATSCCH frames is lower than FACCH priority,

• a RATSCCH message has to be acknowledged in the next 3 frames by the

MS,

• the content of RATSCCH message is applicable 12 frames after this

message,

• in case of failure (ACK_ERR message), a RATSCCH procedure is repeated

twice. If the procedure completely fails, the MS and the BTS use the previous

set of codec modes.

downlink

5k9 to 4k75 81 90 99 108 1176k7 to 5k9 82 91 100 109 118

10k2 to 6k7 83 92 101 110 119

12k2 to 10k2 84 93 102 111 120

FR hysteresis 85 94 103 112 121

5k9 to 4k75 86 95 104 113 122

6k7 to 5k9 87 96 105 114 123

7k4 to 6k7 88 97 106 115 124

HR hysteresis 89 98 107 116 125

SFH 900

TU3

uplink

FR thresholds

HR thresholds

slow MS -

no FH

fast MS -

no FH< 4 FH

ideal FH

(>= 4 freq)




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When amrReserved1 is set to enabled, this procedure is used by the L1m to modify the set of

codec modes, for a FR channel and in case of handover failure with return on the old FR

channel, in order to avoid inconsistency between the BTS and the MS (the BTS sends the

AMR_CONFIG_REQ message).

For TCH/FR, the default transmission phase shall be such that Codec Mode Indications are

sent aligned with TDMA frame 0 in the uplink and with TDMA frame 4 in the downlink. For

TCH/HR, the default transmission phase shall be such that Mode Indications are sent aligned

with TDMA frame 0 or 1 depending on the subchannel in the uplink and with TDMA frame 4 or

5 depending on the subchannel, in the downlink.

If at call setup or after a handover, the Codec Mode Indication is not aligned, an Ater

procedure is engaged in order to change the default phase in downlink direction.

PRINCIPLES

The RATSCCH as the FACCH shares the dedicated channel of the TCH. Contrarily to the

FACCH the RATSCCH is time synchronous. The RATSCCH allows modification of the AMR

configuration (CMI/CMC phasing, Adaptation Thresholds, ACS)..The introduction of the AMR,

Nortel Networks BTS will support the RATSCCH (All Nortel’s BTS from the S4000 DCU4 to

the most recent BTS will support the AMR speech service.)

The RATSCCH message is composed of a preamble and of a message part. Several

messages have been defined. These messages correspond to different procedures. At the

moment the following have been defined:

• Changing of the Active Codec Set• Changing of the thresholds and hysteresis

PRE-HANDOVER

In case of intracell or intercell handover, the adaptation mechanism has to be frozen to the

ICM. For this result, the BTS has to intercept:

• the Assignment Command in case of intracell,

• the Handover Command in case of intercell handover,

and to perform up to 2 codec mode adaptations, in order to activate the initial codec mode

(5k9 kbits in all cases) and to stop the adaptative mechanism.

This induces:

• an increase of around 150ms on the handover duration from the BSS point of

view,

• a delay of around 150ms on the handover starting time from a MS point of

view, but no impact for the end-user in term of voice quality (i.e. same speech

gap).

In case of handover failure when the MS returns on the old channel, the adaptation

mechanism is restarted by the BTS at reception of the Start Measurement message




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4.22.3 TRAFFIC MANAGEMENT MECHANISMS

CHANNEL ALLOCATION

TCH channel allocation is triggered by the reception of an Assignment request or a Handover

request message from the MSC, or in case of an intraBSC handover. The BSC should

determine whether AMR is to be used, and select between FR or HR. This mechanism is

based on proprietary algorithms, which provide to the operator a full control of the allocation.

These decisions are made based on several criteria:

• OAM flags which indicate if the BSC, the TCU, and the cell support AMR, and

strategy selected

• MS capability, which is reported by the MSC in Assignment request or

Handover request messages

• radio context, for instance as evaluated during the SDCCH phase.

The BSC also has to control the BSS version: an AMR channel is activated only if all nodes

managing the call are at least in V14.

FLAG MANAGEMENT

We use the two following parameters:

• coderPoolConfiguration (AMR, fullrate, enhancedfullrate) attribute. This

attribute indicates enumerated speech coding algorithms supported by the

TCU.

• speechMode (halfRateAMR, fullRateAMR, fullrate, enhancedfullrate) attribute.

This attribute indicates speech coding algorithms supported by the cell.

CHANNEL TYPE MANAGEMENT

In order to select the channel type associated to the connection, the BSC uses the channel

rate and type and permitted speech version information, in order to know the MS capability in

term of:

• FR/HR management

• Speech codec

But the chosen channel type is fixed according to radio criteria and some O&M parameters,

and the BSS has the possibility to modify the channel type during the connection, in all cases.

So at reception of the Assignment Request or Handover Request, the following mediation is

done on the Channel Type octet 4:

IF Target TCH = FR TCH

THEN the BSC always allocates a FR TCH




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IF Target TCH = HR TCH

AND IF AMR HR is allowed in the cell

THEN the BSC allocates a HR TCH

ELSE the BSC allocates a FR TCH.

CELL LOAD STATE

The cell load state is used in order to choose between a FR or a HR channel, and is defined

using following parameters:

• hrCellLoadStart

• hrCellLoadEnd

• filteredTrafficCoefficient

Previously to V15.1.1, if hrCellLoadStart = 0, then FR radio channel is always allocated to the

MS, and if hrCellLoadStart > 0, then HR radio channel is allocated to the MS, according to its

radio conditions. For one call, the cell load state is evaluated at the first TCH allocation in the

cell, thus in case of intracell handover, the cell load state is not reevaluated.

In V15.1.1, the feature AMR based on traffic is introduced. The goal is to enhance the HR

allocation in order to take into account the cell load: AMR HR channels are allocated only

during loaded period. The cell load state is evaluated every 10s (see Filtered Erlang traffic andcell load state)

ASSIGNMENT

In case of assignment, according to:

• the speechMode parameter value of the target cell (signalingPoint +

TranscoderBoard + bts parameters)

• the cell load of the target cell

• the radio condition of the MS

the BSC selects the target Channel Type.

To know the radio conditions, the BSC sends to the BTS a Connection State Request and in

the Connection State Ack the BTS gives the following bit map:

• “small zone” bit indicates if the small zone of the serving is eligible in case of

multi-zone cell

• “HR large” bit indicates if the MS has sufficient radio conditions to manage a

HR channel in the large zone of a mullti-zone cell or in normal cell

• “HR small” bit indicates if the MS has sufficient radio conditions to manage a

HR channel in the small zone of a mullti-zone cell or in normal cell




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4.22.4 AMR L1M

Up to V14, L1m algorithms are common for all types of dedicated channel, but due to

performances of AMR channels:

• A FR AMR channel, specially with low codec mode, is more resistant than the

normal FR channel

• A HR AMR channel, is more sensitive to interference than the normal FR

channel

Some new mechanisms dedicated for AMR channels based on "requested codec mode" in

uplink and downlink paths, which are the best representation of the quality in this case, are

designed.

For this reason, RxQual criterion is not used in AMR L1m algorithm, dealing with AMR

channel.

12K2 AND 7K4 CODEC MODE FALSE ACTIVATION

As seen before following codec mode sets are implemented in the BTS:

AMR FR AMR HR

10k2

6k7 6k7

5k9 5k9

4k75 4k75

In AMR L1m mechanisms, the main criterion for L1m is the requested codec mode provided

by the MS or the BTS. With this set of codec modes, it is impossible to detect if the quality is

good or very good (in both cases the MS and the BTS provide the 10k2 or 6k7 codec mode

according to the channel type).

In order to solve this problem, for an half rate channel, a fourth codec mode (7k4) is added to

the list allowing to distinguished between good and very good radio conditions. Thus the half

rate codec mode set becomes:

AMR HR

7k4

6k7

5k9

4k75

For a full rate channel:

• if the radio conditions are good for uplink and downlink, then the 12k2 kbits

codec mode is configured and the 4k75 discarded allowing to distinguish

between good and very good radio conditions (using RATSCCH channel).

• if the radio conditions are bad for uplink or downlink, then the 12k2 kbits

codec mode is removed and the 4k75 is set back (using RATSCCH channel).




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Thus the codec mode set becomes:

AMR FR AMR FR

12k2

10k2 10k2

6k7 6k7

5k9 5k9

4k75

The following algorithm details the way of changing the codec mode set, for both paths:

1) initial state: the active codec mode set is {12k2, 10k2, 6k7, 5k9}

2) during the last 480ms period, at least one 4k75 code mode or 3 * 5k9 codec mode

are requested for uplink or downlink paths, then the active codec mode set is changeto {10k2, 6k7, 5k9, 4k75}

3) if the active code mode set is {10k2, 6k7, 5k9, 4k75} and during the last 2*480ms

period, no 5k9 nor 4k75 code mode is requested for uplink and downlink paths, then

the active codec mode set is change to {12k2, 10k2, 6k7, 5k9}.

POWER CONTROL

The Power Control feature reduces the average interferences level on the Network and saves

mobile batteries.

Power control algorithms are redesigned for AMR calls, in order to take into account the

requested codec mode. With the following parameters (powerControl object), the operator

defines the target codec mode of each channel type:

Uplink target codec

• hrPowerControlTargetMode

• frPowerControlTargetMode

Downlink target codec

• hrPowerControlTargetModeDl

• frPowerControlTargetModeDl

For the uplink path, SNR and CMR criteria are available, but the SNR is more accurate than

the CMR. For the downlink path only the CMR is available. Thus the AMR power control does

not apply same principles for both paths. This new power control mechanism is also controlled

by the 2 classical power control parameters:

• bsPowerControl for the downlink path,

• uplinkPowerControl for the uplink path.




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UPLINK POWER CONTROL

For the uplink path, the criterion is the SNR, averaged on 2 measurement periods. As this

mechanism shall guarantee a voice quality, the target SNR is the upper threshold of the

adaptation mechanism:

Note: for the 12k2 (or 7k4) value, the BTS takes into account the 10k2 (or 6k7) value plus the

FR (or HR) hysteresis.

At each measurement period, the BTS calculates the new MS power using the following

formula:

IF (Filtered_SNR – Target _SNR) > 0

THEN MS_txpwr(N) = MS_txpwr(N-1) – 0.7*( Filtered_SNR – Target _SNR)

ELSE IF

THEN MS_txpwr(N) = MS_txpwr(N-1) + 1.4*( Target _SNR -Filtered_SNR)

Note: From V 16, the reactivity of UL power control is improved as UL SNR measurements

limited to 24 dB (48 in 0.5 dB) are taken out.

DOWNLINK POWER CONTROL

The power control principle is:

• To decrease the power level of one step if the last requested codec mode of

the 480 ms is greater than the target codec mode,

• To increase the power level of one step if the last requested codec mode of

the 480 ms is lower than the target codec mode

Note: in AMR like in EFR, the parameter lRxLevDLP indicates the threshold below which

power control is inhibited.

HANDOVER MECHANISMS

The following table describes which handover mechanisms are impacted by the AMR

introduction

Handover type modifieduplink and downlink quality yes

uplink and downlink strength no

distance no

power budget no

uplink and downlink intra-cell handover yes

capture no

inter-zone yes

directed retry no

Traffic no




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PRINCIPLE

These 4 handovers are based on "(n,p) voting" principle, using the requested codec mode.

The (n,p) voting principle considers the last p requested codec modes, it compares them to

two parameters: a codec mode threshold defined for the procedure and the specific n value

used for the procedure.

If p is set to 2 SACCH periods (2*12), n is set to 10, the target codec mode is the green one,

and then a handover is triggered in the following example:

This principle applies in uplink and downlink direction independently.

This mechanism is managed by the L1m and triggered at the end of each period of

measurement, thus p has to be a multiple of the number of requested codec mode in one

measurement period (i.e. 480 / 40 = 12).

The following parameters are defined in the handOverControl object:

• pRequestedCodec

• nHRRequestedCodec

• nFRRequestedCodec

If the n parameter is set to a value greater than the p parameter, then all associated features

are deactivated. If the target codec mode is the smallest, then the associated feature is

deactivated.

INTERBSC HANDOVER

In case of interBSC handover, according to:

• the speechMode parameter value of the target cell (signallingPoint +

transcoderBoard + bts parameters)

• the cell load of the target cell

• the Current Channel element

• the Cause element

the BSC selects the target Channel Type:

• if one out of these last 2 optional A interface elements is not set in the

Handover Request message, the chosen channel type is FR

• if these 2 elements are present and the half rate is allowed in the target cell,

then the following table is applied:

t

Handover

decision

pRequestedCodec

t

Handover

decision

pRequestedCodec




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Current Channel type 1

CauseHR FR

uplink quality FR FR

uplink strength FR FR

downlink quality FR FR

downlink strength FR FR

Distance FR FR

O&M intervention FR FR

Better cell HR FR

Directed retry FR FR

Traffic HR FR

In all other case, a FR channel is allocated.

INTRABSC INTERCELL HANDOVER

In case of intraBSC handover, following transitions are defined in order to determine the target

channel type:

Initial Channel type

Handover causeHR AMR FR AMR

AMR quality FR AMR FR AMR

DISTANCE FR AMR FR AMR

PBGT HR AMR FR AMR

TRAFFIC HR AMR FR AMRForced HO FR AMR FR AMR

Capture FR AMR FR AMR

Directed retry FR AMR FR AMR

The speechMode parameter value of the target cell and the cell load are also checked in order

to verify that the half rate is allowed in the cell.

With AMR calls, RxLev and RxQual criteria for uplink and downlink are not used and replaced

by an algorithm based on "(n,p) voting" principle, using the requested codec mode.

Following parameters are introduced in order to specify the target requested codec mode for

FR and HR AMR channel:

• amrHRIntercellCodecMThresh

• amrFRIntercellCodecMThresh

In order to manage the eligible cell list, a new handover margin is introduced in the

adjacentCellHandOver object: hoMarginAMR this parameter is used in order to calculate the

Exp2 (this expression is used to evaluate the PBGT criteria for each cell and to classify eligible

cells, please refer to chapter EXP2).




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IF N(Uplink) ≥ nXXRequestedCodec

OR N(Downlink) ≥ nXXRequestedCodec

THEN the Handover is triggered

With N the number of requested codec mode for the uplink or the downlink strictly lower than

AMRXXIntercellCodecModeThreshold (XX stands for HR or FR)

INTRABSC INTRACELL HANDOVER

In order to select the channel type, the BSC applies the following table:

Handover cause original channel type target channel type

normal intra-cell FR FR

Small to large zone FR or HR FR

large to small zone FR FR or HR according to radio conditions*

large to small zone HR HR**

tiering FH to no FH FR FR

tiering FH to no FH HR FR

tiering no FH to FH FR FR

tiering no FH to FH HR HR

AMR FR to HR FR HR

AMR HR to FR HR FR

*The radio conditions are given by the BTS to the BSC using the Current Cell Add information

element in the Handover Indication message.

**If radio conditions are not sufficient in the small zone to manage this HR MS, the MS

remains in the large one, due to the HR priority.

Intracell handover principle is to give to the mobile a better resource in term of interference, if

its C/I is low, with a high C value.

This principle is only applicable to FR AMR mobiles, due to interaction with HR >FR handover:

in these radio conditions, it is really more efficient to allocate a FR radio TS to a HR AMR

mobile, than to perform a handover from an HR TS to a HR TS. This intracell handover is

triggered only if the intracell parameter of handovercontrol object is set to enable.

The following parameter is introduced on the handoverControl object, in order to specify the

target requested codec mode for FR AMR channel:

• amrFRIntracellCodecMThresh

The minimum level to perform an AMR intracell handover is defined by following parameters

on the handoverControl object:

• amriRxLevDLH

• amriRxLevULH




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So the intracell handover uses the following criteria:

IF N(Uplink) ≥ nFRRequestedCodec AND RxLevUL > amriRxLevULH

OR N(Downlink) ≥ nFRRequestedCodec AND RxLevDL > amriRxLevDLH

THEN the handover is triggered.

With N the number of requested codec mode for the uplink or the downlink strictly lower than

amrFRIntracellCodecMThresh for the uplink or the downlink

INTRACELL HANDOVER AMR FR AMR HR

This handover is used to change the channel type of a mobile from FR to HR if the quality is

sufficient.

Due to the high C/I requirement for HR channel, the requested codec mode of "(n,p) voting"

mechanism is fixed by default to 12k2 kbits/s and a dedicated "n" parameter allows to set the

trade-off between quality and capacity:

• nCapacityFRRequestedCodec

The handover is triggered if the "(n,p) voting" principle is fulfilled in both directions.

Note:

• this mechanism is not linked to the intracell parameter of handovercontrol

object.

• this mechanism is deactivated if nCapacityFRRequestedCodec is greater than

pRequestedCodec.

So the handover AMR FR to HR uses the following criteria:

IF N(Uplink) ≥ nCapacityFRRequestedCodec

AND N(Downlink) ≥ nCapacityFRRequestedCodec

THEN the capacity handover is triggered.

With N the number of requested codec mode for 12k2 in the p requested codec mode for the

uplink and the downlink path,

INTRACELL HANDOVER AMR HR AMR FR

This handover is used to change the channel type of a mobile from HR to FR if the quality is

not sufficient.

The handover is triggered if the "(n,p) voting" principle is fulfilled in one direction.

The following parameter is introduced on the handoverControl object, in order to specify the

target requested codec mode for this handover:

• amrHRtoFRIntracellCodecMThresh




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Note: this mechanism is not linked to the intracell parameter of handovercontrol object, and it

is deactivated if amrHRtoFRIntracellCodecMThresh is set to 4k75.

DIRECT HALF RATE TCH ALLOCATION

In order to avoid some unnecessary handover from FR to HR channel, it is mandatory to

evaluate the radio conditions at following stages:

• primo allocation: SDCCH to TCH in a normal cell,

• primo allocation: SDCCH to large zone TCH in a multi-zones cell,

• primo allocation: SDCCH to small zone TCH in a multi-zones cell,

• inter-zone handover from large to small in a multi-zones cell.

and allocate immediately a HR channel if radio conditions are sufficient.

The principle of this mechanism is to compare the RxLev uplink and downlink to dedicated

thresholds, in order to estimate the MS HR capability.

Following parameters are introduced on the handoverControl object, in order to specified

RxLev thresholds for this handover:

• amrDirectAllocIntRxLevDL

• amrDirectAllocIntRxLevUL

• amrDirectAllocRxLevDL

• amrDirectAllocRxLevUL

So the direct half rate TCH allocation uses the following criteria:

In a normal cell or in the large zone:

IF RxLevDL > amrDirectAllocRxLevDL and RXLevUL > amrDirectAllocRxLevUL

THEN the direct HR TCH allocation is eligible

In a small zone:

IF RxLevDL > amrDirectIntAllocRxLevDL and RXLevUL > amrDirectIntAllocRxLevUL

THEN the direct HR TCH allocation is eligible

In v17.0, the Direct TCH Allocation mechanism has been improved to take into account thecase where only a short, not fully reliable, measurement average is available. In that case, all

algorithm criteria are tightened by adding the hoMarginBeg parameter to the appropriate

thresholds (amrDirectAllocIntRxLevDL, amrDirectAllocIntRxLevUL, amrDirectAllocRxLevDL,

amrDirectAllocRxLevUL).




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SUMMARY

The following table presents a summary of all new L1m decisions:

HO decision channel type p value for (n,p) voting n value for (n,p) voting target codec

quality intercell UL / DL

TCH FR pRequestedCodec nFRRequestedCodec amrFRIntercellCodecMThresh

TCH HR pRequestedCodec nHRRequestedCodec amrHRIntercellCodecMThresh

quality intracell UL / DL

FR FR TCH FR pRequestedCodec nFRRequestedCodec amrFRIntracellCodecMThresh

HR FR TCH HR pRequestedCodec nHRRequestedCodec amrHRtoFRIntracellCodecMThresh

capacity intracell

FR HR TCH FR pRequestedCodec nCapacityFRRequestedCodec fixed to FR codec 12k2

Direct HR TCH allocation channel type averaging window thresholds

outer zone SDCCH 1 … rxLevHreqt*

rxLevHreqave

amrDirectAllocRxLevDL

amrDirectAllocRxLevUL

inner zone SDCCH

TCH FR

TCH HR

1 … rxLevHreqt*

rxLevHreqave

amrDirectAllocIntRxLevDL

amrDirectAllocIntRxLevUL

* in this case, all available measures, up to rxLevHreqt are taken into account.0




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Following figures illustrate all possible transitions for an AMR call, in a multi-zones cell

environment:

INTRACELL HANDOVERS ON QUALITY

INTRACELL HANDOVERS ON CAPACITY

Tiering BCCH to FH FR

Tiering BCCH to FH HRFR

Intracell FR or HR FR

Interzone FR or HR FR

Intracell FR or HR FR





Intracell FR or HR FRIntracell FR or HR FR

Interzone FR or HR FRInterzone FR or HR FR

Intracell FR or HR FRIntracell FR or HR FR


Tiering BCCH to FH HR

FR

HR

Interzone FR FR or HR

Interzone HR HR

Capacity FR HR

HR

Capacity FR HR

Direct TCH

allocation

FR or HR

FR or HR


Tiering BCCH to FH HR

FR

HR

Interzone FR FR or HR

Interzone HR HR

Capacity FR HR

HR

Capacity FR HR

Direct TCH

allocation

FR or HR

FR or HR




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AMR FR REQUEST

In case of AMR FR request, there is no specific mechanism. The request is granted in the

same conditions as for a non-AMR circuit-switched call.

AMR HR REQUEST

Before v17.0, in case of an AMR HR request, if a preemption has to be done, then the

allocated channel following preemption is an AMR FR channel.

From v17.0, if the “AMR-HR on preempted pDTCH” feature is activated (v17 parameter

gprsPreemptionForHr = enabled), then the BSC is able to preempt a shared GPRS timeslot to

serve an AMR-HR request. The algorithm is as follows :

When the BSC receives an assignement or a handover request for a half-rate speech channel,the BSC searches for an available HR channel in the following order of preference :

• free half-rate channel of a TCH physical channel whose other half-rate channel is

already allocated to a voice AMR HR call (no dialog between BSC and PCU is

needed)

• free TCH physical channel (no dialog between BSC and PCU is needed)

• free half-rate channel of an already preempted PDTCH whose other half-rate channel

is already allocated to a voice AMR HR call (no dialog between BSC and PCU is

needed)

• half-rate channel of a newly preempted PDTCH (BSC and PCU must negotiate)

This feature for AMR-HR preemption may have an impact on the AMR based on Traffic

threshold settings, see 4.23.7




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4.22.7 ENGINEERING RULES

QUEUING/PRIORITY 0

• queuing is not possible for an HR only request,

• for a FR or HR request in queue, only a FR TCH can be allocated.

The number of priority 0 TS takes into account only radio TS which are completely free (i.e. a

free half rate TS is count for 0).

TCH SIGNALLING

A signaling half rate TCH can not be activated at reception of Channel Required.

If a “signaling” Assignment Request (channel type: “speech/ data indicator” field), for a mobileusing a half rate TCH, an assignment procedure is triggered to a SDCCH channel and the

associated CIC is released (this case occurs at the end of a speech call, if a SMS procedure is

started and not finished).

If a “signaling” Assignment Request (channel type: “speech/ data indicator” field), for a mobile

using a full rate TCH, a channel mode modify procedure is triggered to a signaling TCH

channel and the associated CIC is released (this case occurs at the end of a speech call, if a

SMS procedure is started and not finished).

If an AMR HR or FR Assignment Request is received for a mobile using a signaling FR TCH,

the BSC modifies the current signaling FR TCH to a AMR FR TCH and later, if radio

conditions are sufficient, then a handover from AMR FR to AMR HR will be triggered by the

BTS (see section “Principles/ L1m/Handover mechanisms/ handover HR->FR”).

AUTOMATIC CELL TIERING

This mechanism has to be enhanced as show below, in order to take into account AMR HR

calls:

• P% is evaluated as:

• FH_HR% is the percent of HR calls managed by the hopping pattern in the

cell,

• HR% is the percent of HR calls managed in the cell.

These 2 percentages are calculated by the BTS.

P%=


(Total number of TCH in the cell – nbLargeReuseDataChannel) * (1 + HR%)P%=


(Total number of TCH in the cell – nbLargeReuseDataChannel) * (1 + HR%)




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GENERAL PROTECTION AGAINST HO PING PONG

Due to AMR L1m introduction, a new cause value is added in hoPingPongCombination:

AMRquality. This value is used in case of AMR handover triggered for alarm purpose.

In case of interBSC handover, in order to distinguish between RxQual handover and AMR

quality handover, the BSC uses following rules:

• If the handover cause = RxQual and the speech version <> AMR then the

Handover cause = RxQual.

• If the handover cause = RxQual and the speech version = AMR then the

Handover cause = AMR quality.

HANDOVER EFR/FR - AMR

For handover from an AMR cell to a non-AMR cell it is performed via the A interface using

external handover mechanism, in order to allow the fallback to EFR or FR channel (according

to Assignment Request order).

For handover from a non-AMR cell to an AMR cell, in order to decrease the MSC load, the call

is not upgraded to AMR and a normal EFR handover occurs.

Note that interBSC procedure may increase the number of dropped call, so it is recommended

to minimize that trnasition period.

TDMA CONFIGURATION

Due to the half rate channel introduction and to limit the number of contexts in the BSC, the

number of SDCCH per TDMA is limited as following:

normal cell:

• Maximum number of SDCCH per TDMA: 2,

• only one SDCCH TS managed by odd TS per TDMA,

• only one SDCCH TS managed by even TS per TDMA.

extended cell:

• Maximum number of SDCCH per TDMA: 1.

CAUTION!

It is highly recommended to respect that TDMA configuration in case of activation of AMR.




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AMR HR-FR INTERWORKING

In case of deactivation of AMR FR service, following points have to be highlighted:

• direct HR TCH allocation is available, even if AMR FR is not configured in the

cell,

• handovers from FR radio TS to AMR HR are triggered on “requested codec

mode” criterion, but this criterion is available only for AMR calls, thus this kind

of handover is not possible from a FR or EFR channel and decreases the

AMR HR efficiency,

• handovers from (or to) an AMR HR channel to (or from) EFR channel are

performed using an external handover procedure and thus induce:

• more load on the MSC,

• more perturbations on the voice quality, thus it is mandatory to activate AMRFR service, in case of AMR HR activation.

4.22.8 AMR BASED ON TRAFFIC

PRINCIPLE

Before the feature introduction the choice between an half rate and full rate channel was

based only on radio criteria, thus in order to guarantee the voice quality at any time the

operator had to tune the network with conservative values.

With the introduction of AMR based on traffic, AMR HR channels are allocated only during

loaded period, so the operator could choose more aggressive radio thresholds and then get

more radio capacity for the same number of TRX.

In order to minimize impacts of this strategy, this feature tunes the half rate penetration

according to the cell load:

FR capacity

HR capacity

HR

FR

FR capacity

HR capacity

HR

FR




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This feature is based on a smooth mechanism, which allows anticipating the cell load and

switching the allocation into HR mode, when an Erlang threshold is reached.

The following picture illustrates the interworking between these 2 kinds of mechanisms over24 hours:

Two typical periods are observed:

• Low traffic: all calls are allocated in full rate mode and the blocking is

managed thanks to directed retry and traffic handovers features.

• High traffic: call are allocated in half or full rate modes, according to radio

conditions of each calls and the ultimate blocking is managed thanks to

directed retry and traffic handovers features.

FILTERED ERLANG TRAFFIC AND CELL LOAD STATE

Prior to V18, the Filtered Erlang Traffic used the following formula

n n-1

busy_TCH_TS Filtered_TCH_ratio = a* + (1 - a) * Filtered_TCH_ratio

available_TCH_TS

where:

• Filtered_TCH_ration is the busy TCH ratio managed by the cell at period n.

• α is the filter coefficient (filteredTrafficCoefficient parameter).

• busy_TCH_TS is the number of TCH TS allocated to a FR or a HR TCH call

(in case of multi-zones cell, traffic of both zones is taken into account).

• Available_TCH_TS is the number of TCH TS configured and available in the

cell (in case of multi-zones cell, traffic of both zones is taken into account).

The initial value of Filtered_TCH_ration is set to 0.

FR->HR threshold

Max HR

capacity

Max FR

capacity

Traffic

24 hours

t

Avg Erlang

Number of

allocated TCH

Full rate area

Half rate area

Blocking managed

thanks to directed retry

and HO traffic

Blocking managed


and HO traffic

FR->HR threshold

Max HR

capacity

Max FR

capacity

Traffic

24 hours

t

Avg Erlang

Number of

allocated TCH

Full rate area

Half rate area

Blocking managed


and HO traffic

Blocking managed


and HO traffic

Max HR

capacity

Max FR

capacity

Traffic

24 hours

t

Avg Erlang

Number of

allocated TCH

Full rate area

Half rate area

Blocking managed


and HO traffic

Blocking managed


and HO traffic




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From V18, thanks to AMR maximization introdution the the filtered Erlang evaluation was

modified to take into account a configurable number of shared PDTCH

Where:

• Filtered_Erlang is the number of Erlang managed by the cell at second n.

• α is the filter coefficient (filteredTrafficCoefficient parameter).

• busy_TCH_TS is the number of TCH TS allocated to a FR or HR TCH call

voice in this cell (in case of multi-zones cell, traffic of both zones is taken into

account).

• Preempted_PDTCH_ is the number of PDTCH TS allocated to a FR or HR

call voice in this cell (in case of multi-zones cell, traffic of both zones is taken

into account).• shared PDTCH_ratio is a percentage of shared PDTCH TS (configured and

available) taken into account in the Filtered_Erlang.

• available_TCH_TS is the number TCH TS (configured and available) in the

cell

• available_PDTCH is the number PDTCH TS (configured and available) in the

cell

• MinNbrGprsTS is the number of GPRS TS in the cell (cell object parameter)

to guarantee a minimal number of radio TS allocated to GPRS service.

This formula is valid for AMR Based on Traffic and AMR maximization algorithm.

Note that if the denominator of the Filtered_Erlang formula is null or negative, no computation

is done and the previous value of Filtered_Erlang value is kept.

This filtered busy TCH ratio is then compared to the 2 thresholds HRCellLoadStart and

HRCellLoadEnd in order to determine the cell load state:

• If (Filtered_TCH_ration < HRCellLoadEnd),

Then Cell_Load_Staten = min(max (0, Cell_Load_Staten-1 -1); nb of in service DRX)

• Else if (Filtered_TCH_ration >= HRCellLoadStart),

Then Cell_Load_Staten = min(nb of in service DRX, Cell Load_Staten-1 +1).

• Else Cell_Load_Staten = min(Cell_Load_Staten-1; nb of in service DRX)

The initial value of this Cell_Load_Staten is set to 0.

This mechanism is activated whatever values of all associated parameters (AMR FR and / or

HR activated or not, HRCellLoadStart, HRCellLoadEnd …), in order to allow the monitoring at

the OMC-R level of this mechanism.

)1( _ *)1(

_ _ *) _ ( _ _

)) _ _ * _ (Pr _ _ (*)( _ −−+

−+

+= N ErlangFiltered

ratioPDTCH shared TS MinNbrGprsPDTCH availableTS TCH available

ratioPDTCH shared PDTCH eempted TS TCH busy N ErlangFiltered α α




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In case of TDMA / TRX defense mechanism, the BSC has to take into account the new

number of DRX in service at the next period, in order to evaluate the cell load state.

TRAFFIC MANAGEMENT PRINCIPLE

The 3 algorithms used to allocate a HR channel to a mobile are tuned in order to be adapted

to the cell load.

DIRECT HALF-RATE ALLOCATION

Direct half rate allocation: the range between the OMC-R RxLev threshold and -48dBm (the

deactivation value) is divided in N sub-range, thus new subthresholds are dynamically created

by the BSC. At each cell load state modification, appropriate sub-thresholds is used by the

BTS:

The principle is for the BSC to adapt the following OMC-R parameters according to the cell

load state:

• AMRDirectAllocRxLevUL

• AMRDirectAllocRxLevDL

• AMRDirectAllocIntRxLevUL

• AMRDirectAllocIntRxLevDL

The threshold associated to the cell load state i is evaluated according to the following

formula:

amrDirectAlloc

(Int)RxLevxx-110 -48 dBm

Cell load state

S0

S1

S2

S3

S4

SmaxRxLev

distribution

RxLev1RxLev2RxLev3RxLev4amrDirectAlloc

(Int)RxLevxx-110 -48 dBm

Cell load state

S0

S1

S2

S3

S4

SmaxRxLev

distribution

RxLev1RxLev2RxLev3RxLev4

Nb_DRX-iThreshold_i = int AMRDirectAllocyyRxlevxx + (-48 - AMRDirectAllocyyRxlevxx)*

Nb_DRX

⎡ ⎤⎢ ⎥⎣ ⎦




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Where:

• xx is used for UL or DL,

• yy is used for int or nothing.

Every 10 seconds if needed, new thresholds are sent to all DRX.

The initial value of this mechanism is the threshold_0 (-48dBm),

At the end of a defense TDMA procedure, current thresholds are sent to the BTS.

This mechanism is activated only if:

• at least one OMC-R threshold is not equal to -48.

• The AMR HR service is activated in the cell (speechMode parameters of the

BSC & cell object)

In case of modification of one AMRDirectAllocyyRxlevxx parameter, the new value is takeninto account at the next period.

FR TO HR HANDOVER

FR to HR handover: this handover is activated DRX per DRX according to the cell load state:

• S0: no DRX is configured in order to allow the FR to HR handover

• Si: i DRX are configured in order to allow the FR to HR handover and N-i-1

are configured in order to deactivate this handover.

The BSC chooses the i DRX in the cell according to the AMR FR radio allocator priority.

Highest priority TDMA are switched in FR->HR mode in first. Every 10 seconds if needed, new

parameters are sent to all DRX.

The initial is no DRX activated, especially at the end of a defense TDMA procedure.

In case of modification of any AMR FR to HR handover parameter, the new value is taken into

account at the next period.

All Handover Indication messages sent by the BTS, have to be managed by the BSC

whatever the cell load state.

This mechanism is activated only if:

• nCapacityFRRequestedCodec not greater than pRequestedCodec.• The AMR HR service is activated in the cell (speechMode parameters of the

BSC & cell object)




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INTRA CELL HANDOVER

From V18, the following table describes the BSC mediation in case of intra-cell

handover for an AMR call with the cell in AMR Based on Traffic congestion state:

AMR Based on Traffic

Intra-cell incoming handover mediation


Handover Cause

HR AMR FR AMR

Intracell uplink

FR only FR only

Intracell downlink

FR only FR only

Capture

FR only FR only

Inter-zone (outer to inner zone) HR preferred (***) HR preferred (***)

Inter-zone (inner to outer zone) FR only FR only

Frequency tiering FR only FR only

Alarm intra-cell HO (FR => FR) for uplink criteria

in case of AMR FR channelNot applicable FR only

Alarm intra-cell HO (FR => FR) for downlink

criteria in case of AMR FR channelNot applicable FR only

HR => FR HO for uplink criteria in case of AMR

HR channelFR only Not applicable

HR => FR HO for downlink criteria in case of

AMR HR channel

FR only Not applicable

Capacity HO (FR => HR) for uplink and downlink

criteria in case of AMR FR channelNot applicable HR only

(***) The HR or FR → HR inter-zone handover is only possible if the HR eligibility in

the inner zone is allowed by the BTS inside the HANDOVER INDICATION message

(i.e. the radio conditions are sufficient to allow HR).

AMR HR preferred is activated only if the AMR HR service is activated in the target

cell (speechMode parameters of the BSC and cell object).




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INTER CELL HANDOVER

From V18, the following table describes the algorithm used on the reception of a HANDOVER

REQUEST inter-cell (from the MSC or internal BSC) for an AMR call with the target cell in

AMR Based on Traffic congestion conditions (Cell Load State > 0):

AMR Based on Traffic

Inter-BSC and inter-cell intra-BSC incoming handover mediation


Handover Cause

HR AMR FR AMR

Uplink quality (*) FR only FR only

Uplink strength (*) FR only FR only

Downlink quality (*) FR only FR only

Downlink strength

(*) FR only FR only

Distance FR only FR only

O&M intervention FR only FR only

Better cell HR preferred HR preferred(**)

Directed Retry FR only FR only

Traffic HR preferred HR preferred(**)

(**) New behavior introduced with AMR Based on Traffic evolution.

(*) Note that this handover causes include following Alarm AMR causes:

• Alarm inter-cell HO for uplink criteria in case of AMR FR channel

• Alarm inter-cell HO for downlink criteria in case of AMR FR channel

• Alarm inter-cell HO for uplink criteria in case of AMR HR channel

• Alarm inter-cell HO for downlink criteria in case of AMR HR channel




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4.22.9 AMR MAXIMIZATION

PRINCIPLE

The aim of this feature is to maximize usage of AMR HR in order to reduce congestion, even if

this objective could lead to potential voice quality degradation. It offers temporarily higher cell

capacity to manage traffic peak

• by disabling the RF checks for HR allocation, i.e. forcing 100% new call in HR

• by disabling fall back in AMR FR for ongoing call

• by forcing all incoming handover in AMR HR whatever the received cause

Area of AMR HR maximization application is configurable through 2 new thresholds in additionto the existing “AMR based on traffic” algorithm (See figure below):

• fullHRCellLoadStart

• fullHRCellLoadEnd.

This function is active as soon as these 2 new thresholds are both different from 100.

In case of modification of one any new parameter, the new value is taken into account at the

next period.

Note that the AMR Half Rate speech mode is a pre-requirement of AMR Maximization.

Without Half Rate capacity allowed, all calls will be allocated in FR mode whatever the cellstate (normal, high traffic or congested).

FR - >HR threshold

Max HR capacity

Max FR capacity

Traffic

24 hourst

Avg Erlang

Number of

allocated TCH

Full rate area

Blocking managed thanks to directed retry

and HO traffic


and HO traffic

HRRCellLoadEnd

-

Max HR capacity

Traffic

24 hourst

Avg Erlang

Number of

allocated TCH

Full rate area


and HO traffic


and HO traffic

Max HR capacity

Max FR capacity

Traffic

24 hourst

Avg Erlang

Number of

allocated TCH

Full rate area

AMR HR based on traffic area


and HO traffic


and HO traffic

AMR HR maximization

HRCellLoadStart

FullHRCellLoadStart

FullHRCellLoadEnd




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AMR MAXIMIZATION ALGORITHM

This filtered erlang defined for AMR based on traffic is also used for AMR maxization

algorithmto. The term congestion period used in the following sentence means cell is in AMR

maximization conditions. Indeed the filtered busy TCH ratio obtained thanks to filtered erlang

formula is then compared to the 2 new thresholds fullHRCellLoadStart and fullHRCellLoadEnd

in order to determine the cell load state therefore the congestion period

If the cell is not in congestion period then

If the Filtered erlang is equal or greater than fullHRCellLoadStart, the cell is at the

beginning of the congestion period:

• Direct Half rate allocation (primo allocation) shall be forced in HR mode.

Note that the AMR HR Direct allocation thresholds remain at their previous value

and will be only updated at the end of congestion state.

• The HR to FR handover shall be deactivated: fall back to AMR FR not possible for

on going AMR HR (see Handover during congestion period). In order to prevent

those handovers, the Extended Current Cell Parameters message is sent to all

DRX with the parameter AMRHRToFRIntracellCodecModeThreshold set to

4.75.This parameter is in the AMR Handover Parameters IEI of the Extended

Current Cell Parameters message.

• all incoming Handover shall be forced to Half rate mode whatever the cause

received in the request of the handover if the MS capability supports the HR mode

(channel type);

• all intra cell handover FR to HR rate mode are authorized for all DRX

• The cell load state continues to be calculated.

Else the HR calls are managed by AMR Based on Traffic algorithm

If the cell is in congestion period then

If the Filtered erlang is lower than fullHRCellLoadEnd: The cell is at the ending of

congestion period.

In order to update the controls of the Handover by the BTS, the Extended Current Cell

Parameters message is sent to all DRX with the parameter

AMRHRToFRIntracellCodecModeThreshold set to MMI value.

If the AMR based on Traffic is activated, the current traffic load (AMR BOT criteria) is

calculated thanks to the cell load state elaborated during the congestion period.

New thresholds are elaborated based on this current load and sent to all DRX

using the Extended Current Cell parameters message. The number of DRX allowing

the FR to HR handover is updated according to the current cell load state value.

Else, the cell stays in congestion period. The cell load state continues to be elaborated




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HANDOVER DURING CONGESTION PERIOD

During AMR maximization period, the MS on an AMR-HR channel should not be handed over

to an AMR-FR resource in the serving cell, that is to say that AMR quality intracell handover

on uplink CMC (Codec mode command) or downlink CMR (Codec mode request) shall be

inhibited setting the AMRHRToFRIntracellCodecModeThreshold to 4.75 codec value. AMR

codec mode adaptation is not impacted as it is not correlated with AMR handovers.

Note that, as the AMR Based on Traffic and AMR Maximization thresholds can be reached at

the same time, the AMR Maximization supersedes the AMR BOT mechanism in case of

conflict.

The following table describes the algorithm used on the reception of a handover request inter

cell (from the MSC in the Handover Request message or internal BSC) for an AMR call.

It is based on the value of channel rate and type and handover cause received in the

Handover Request.

AMR Maximization

Inter-BSC and inter-cell intra-BSC incoming handover mediation

Handover cause

Target Cell in

congestion and

MS supports HR

mode

Target Cell not in

congestion

Uplink quality (**) HR FR only

Uplink strength (**) HR FR only

Downlink quality

(**) HR FR only

Downlink strength

(**) HR FR only

Distance HR FR only

O&M intervention HR FR only

Better cell HRFR only or HR

preferred (*)

Directed Retry HR FR only

Traffic HRFR only or HR

preferred (*)

(*): HR preferred according to the AMR Based on Traffic condition: cell Load

State > 0




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(**) Note that this handover causes include following Alarm AMR causes:

• Alarm inter-cell HO for uplink criteria in case of AMR FR channel

• Alarm inter-cell HO for downlink criteria in case of AMR FR channel

• Alarm inter-cell HO for uplink criteria in case of AMR HR channel

• Alarm inter-cell HO for downlink criteria in case of AMR HR channel

The following table describes the BSC mediation in case of intra-cell handover for an AMR call

with the cell in AMR Maximization congestion state:

AMR Maximization

Intra-cell incoming handover mediation

Handover cause

Target Cell in congestion and

MS supports HR mode

Intracell uplink

HR

Intracell downlink

HR

Capture

HR

Inter-zone HR

Frequency tiering HR

Alarm intra-cell HO (FR => FR) for uplink criteria in

case of AMR FR channelHR

Alarm intra-cell HO (FR => FR) for downlink

criteria in case of AMR FR channelHR

HR => FR HO for uplink criteria in case of AMR HR

channelHR

HR => FR HO for downlink criteria in case of AMR

HR channelHR

Capacity HO (FR => HR) for uplink and downlink

criteria in case of AMR FR channelHR




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AMR MAXIMIZATION INTERWORKING

Since ABOT (AMR Based on Traffic) and AMR maximization can be activated independantly,

the following conditions are required for the ABOT and AMR Maximization thresholds

• In case where both ABOT & Maximization activated i.e hrCellLoadStart <> 100 AND

fullHRCellLoadStart <> 100

Then the following rule must be followed

fullHRCellLoadStart > fullHRCellLoadEnd

fullHRCellLoadStart > hrCellLoadStart

fullHRCellLoadEnd > hrCellLoadEnd

• In case where ABOT not activated & Maximization activated i.e hrCellLoadStart =100

AND fullHRCellLoadStart <> 100Then the following rule must be followed

fullHRCellLoadStart > fullHRCellLoadEnd

• In case where ABOT activated & Maximization not activated i.e hrCellLoadStart <>

100 AND fullHRCellLoadStart = 100

Then the following rule must be followed

hrCellLoadStart >= hrCellLoadEnd

4.22.10 QUEUING HRThe previous Nortel implementation does not allow a direct AMR HR allocation for a call that is

being queued. In V18, the requested AMR-HR from queuing can be served in AMR-HR mode.

Moreover in case of one HR resource is released, an HR request queued should take

precedence over a FR request in same queue (same internal priority) in a cell congested or in

high traffic state. This new functionality is available by default on the V18 software load, no

need to activate the feature.

.

FR requested HR requested

Before V18 BSS version FR FR

AMR Maximization (Congestion period) HR HR

AMR Based On Traffic (cell load state > 0) FR HR

AMR Based On Traffic (cell load state = 0) FR FR




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FEATURE ACTIVATION

A dedicated cell class 2 parameter, enableRepeatedFacchFr , is used to enable the feature by

chosing a codec threshold or to disable the support of Repeated FACCH in each cell.for AMR

FR

Since V18 a new dedicated cell class 2 parameter enableRepeatedFacchHr , is used to enable

the feature for AMR HR calls

MECHANISM OF THE FEATURE

When the Repeated FACCH feature has been enabled on the cell, each time the AMNU entity

needs to re-transmit an I-frame on FACCH due to T200 expiry, it sends this frame again to the

SPU entity (with a flag related to the retransmission). The SPU entity sends first the I-frame on

FACCH in TDMA frame M as it does when the feature is disabled. And if the selected CODEC

is lower than the threshold set to activate the feature, it stores the LAPDm frame to berepeated in TDMA frame M+ 8 or M+ 9 for AMR FR calls (resp TDMA frame M+ 6 or M+ 7 for

AMR HR calls if activated)

When repeating FACCH messages, T200 is started when transmitting the subsequent FACCH

(~ 40 ms later) to cope with the case where an MS fails to decode the downlink FACCH block

used to send the first instance of a repeated LAPDm frame.




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PERFORMANCE

When repeating a frame, the applicable T200 duration is increased by about 40 ms (~20%).

This induces a longer time for drop call detection with T200 mechanism because N200 cannot

be modified.

In addition, a new MS shall soft combine the frames to optimize the decoding probability

whereas legacy mobile will simply see an increased probability of decoding Lapdm frame. The

expected benefit for mobiles using soft combining is about 4 dB gain and about 2 dB gain for

legacy mobiles.

This graph presents the expected benefits on softcombining MS and lecacy MS.

Soft combining gain

Legacy MS gain




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4.22.12 TX POWER OFFSET FOR SIGNALING CHANNELS

In order to increase the signaling channels (FACCH and SACCH) robustness in downlink, BTS

may use a power offset (above the Tx power applicable for speech) to transmit the signalingbursts.

The benefit in term of C/I is depending on the power offset for the signaling robustness and

allows the operator increasing the fractional load and thus the spectrum efficiency. Voice

quality can be still acceptable thanks to the use of robust AMR codec.

PRINCIPLE OF THE FEATURE

The Tx Power Offset for Signaling Channels is applicable to:

• The first transmission of HO COMMAND and ASSIGNMENT COMMAND for all AMRcalls in order to maximize the likelihood of decoding these messages from the first

instance,

• Every re-transmission of I-frame on FACCH for all AMR calls (HR and FR) in order to

maximise the likelihood of decoding these messages.

• Every RR and REJect frame on FACCH corresponding to an uplink retransmission for

all AMR calls (HR and FR) in order to improve the two-ways robustness.

• Every UA (respectively DM) frame on FACCH corresponding to an uplink re-

transmission of SABM (respectively DISC) frames for all AMR calls (HR and FR) in

order to improve the two-ways robustness.

• The transmission of all SACCH frames for AMR FR 4.75 kbps, 5.9 kbps and 6.7 kbps

calls (tunable with an OMC-R parameter) in order to avoid radio link time-out (that

leads to drop calls.

On theses messages a power offset (tunable from the OMC-R) is applied up to the nominal Tx

power.

Note: The power offset applies (up to the nominal Tx power of the BTS) on BTS18000, ecell,

as well as S8000 and S12000 fitted with e-DRX or DRX-ND3. For other BTS hardware, the

feature does not apply. In addition this feature is not applicable on BCCH TRX (PA is alwaystransmitting with Pmax and transmitting power should not fluctuate).




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FEATURE ACTIVATION

This feature is activated at cell level; dedicated class 2 parameters are used to enable/disable

the feature in each cell. The parameters related to tune the feature are the following:

• facchPowerOffset

• sacchPowerOffset

• sacchPowerOffsetSelection

Note: If the BTS hardware (DRX or RM) does not support the signalling offset mode (up to

Pnominal), the facchPowerOffset and sacchPowerOffset provisioning is not considered and

the DRX or RM behaves as it behaves when facchPowerOffset and sacchPowerOffset are setto 0 dB.

FEATURE DESCRIPTION

The Tx Power Offset for Signaling Channels is applicable to different type of message;

hereafter the process for each specific handling:

SPECIFIC HANDLING OF HO COMMAND AND ASSIGNMENT COMMAND

For all AMR calls, these messages are transmitted with the maximum power (considering

facchPowerOffset) from the first instance in order to maximize the likelihood of decoding thesemessages with no LAPDm repetition at all, and therefore avoid as far as possible the drop

calls during (inter-cell or AMR triggered) handover procedure.

Since these messages can be segmented, the power offset applies on all segments: the level

3 entity flags all frames of the HO COMMAND and ASSIGNMENT COMMAND messages then

SPU entity checks this flag in each I-frame to apply (or not) the power offset

(facchPowerOffset) on the transmitted frame.

When applying the power offset,

First case:

IF PWR + facchPowerOffset ≤ Pnominal

THEN

SPU modifies the dynamic power control in accordance with PWR + facchPowerOffset




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Second case:

IF PWR + facchPowerOffset > Pnominal

THEN

SPU set the dynamic power control to: 0 BTS transmits the frame at Pnominal

Note: PWR is the BTS transmit power computed by L1M power control algorithm and

applicable for speech and Pnominal is the BTS Tx power set by the static power control

SPECIFIC HANDLING OF RE-TRANSMITTED I-FACCH FRAMES, RR ANDREJECT CORRESPONDING TO RE-TRANSMITTED UPLINK FACCHFRAMES AND UA CORRESPONDING TO RE-TRANSMITTED SABM ORDM

For all AMR calls, every re-transmission of FACCH frames as well as:

• UA (with F bit set to 1) corresponding to a retransmitted SABM or Disconnect Mode,

• and RR and REJect frames on FACCH (with F bit set to 1) corresponding to an uplink

retransmission of a FACCH frame

are transmitted with the maximum power in order to maximise the likelihood of decoding

these messages and therefore avoid as far as possible the drop calls due to N200 overrun.

The BTS LAPDm entity flags each FACCH frame mentioned here-above then SPU entity

checks this flag and apply (or not) the power offset (facchPowerOffset) on the re-transmitted

frame.

When applying the power offset:

SPU (as describes for HO command and assignment command) either modifies the dynamic

power control in accordance with PWR + facchPowerOffset or set this power control to 0

leading the BTS to transmit the frame at Pnominal.

SPECIFIC HANDLING OF SACCH FRAMES

For AMR calls, depending on sacchPowerOffsetSelection provisioning, the transmission of

SACCH frames for AMR FR 4.75 kbps, 5.9 kbps and 6.7 kbps calls are transmitted with the

maximum power (considering sacchPowerOffset) in order to avoid radio link time-out (that

leads to drop calls) and the drop calls due to N200 overrun (for re-transmission).

For SACCH transmission, SPU entity, according to the last selected AMR CODEC and

sacchPowerOffsetSelection provisioning, applies (or not) the power offset (sacchPowerOffset)on the transmitted bursts.




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When applying the power offset:

First case:

IF PWR + sacchPowerOffset ≤ Pnominal

THEN

SPU modifies the dynamic power control in accordance with PWR +

sacchPowerOffset

Second case:

IF PWR + sacchPowerOffset > Pnominal

THEN

SPU set the dynamic power control to: 0 BTS transmits the frame at Pnominal

Note: Correction of RxLev (to remove the impact of the power offset on Tx power control

mechanism) can be approximated by SPU entity and conveyed to the L1m. In another hand,

correction of CMR is not possible since BTS does not have the SNR info from MS. The impact

on the choice of AMR CODEC cannot be by-passed see [R36]




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ENHANCEMENT OF AMR POWER CONTROL MECHANISM

Since this feature improves the downlink robustness, new parameters are introduced to define

dedicated target for uplink and downlink AMR CODEC.

The existing parameters (hrPowerControlTargetMode and frPowerControlTargetMode) still

apply on uplink and two new parameters are introduced for downlink targets:

• hrPowerControlTargetModeDl: downlink AMR codec target to define the downlink

power control threshold for HR AMR calls,

• frPowerControlTargetModeDl: downlink AMR codec target to define the downlink

power control threshold for FR AMR calls,

With setting a lower codec as a Downlink Power control target:

• A more protected AMR speech codec is used in downlink,

• Overall BS attenuation is higher and the overall interference level is decreased

accordingly.

So, in poor radio condition, the transmission power for signaling burst may stay identical

thanks to the Power offset while interference level has decreased.

Since the low target codec for Downlink Power control cannot be reached if the RxLev Power

control threshold limits the BS attenuation and if the Tx Power Offset for Signaling Channels

feature is enabled, lRxLevDLP for AMR communication is set to:

LRxLevDLP - min (facchPowerOffset, sacchPowerOffset).




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4.23. WPS - WIRELESS PRIORITY SERVICE

The current United States industry focus in support of National Security and Emergency

Preparedness telecommunications services is to specify the requirements for Wireless Priority

Services. The initial deployment of WPS is intended to allow qualified and authorized NS/EP

users to obtain priority access to radio traffic channels during situation when Commercial

Mobile Radio Service (CMRS) network congestion is blocking call attempts.

WPS is intended to facilitate emergency response and recovery operations in response to

natural and man-made disasters and events, such as floods, earthquakes, hurricanes, and

terrorist attacks. WPS is also intended to support both national and international emergency

communications.

4.23.1 PRINCIPLE

If a Service user invokes WPS (Wireless Priority Service) and no radio traffic channel is

available in the cell, the WPS request shall be queued according to the WPS priority, the call

initiation time and the state of the queue for the cell.

This feature is an improvement of the queuing services available to WPS users.

The WPS queuing principle is the following:

• The eight (8) current queues are kept unchanged

• Five (5) new queues are added an dedicated to WPS request

For public queue management and related parameters, refer to chapter Queuing.

4.23.2 WPS – QUEUING MANAGEMENT

The new queuing management of WPS requests is activated when queuing is driven by the

MSC (bscQueuingOption parameter is set to “allowed”) and WPS management is activated

(wPSManagement parameter is set to “enabled”)

CAUTION!

The bscQueuingOption is a class 1 parameter, which means that parameter can be set only

when the parent bsc object is locked.

It is important to underline that the internal queues associated with WPS requests and the

internal queues associated with public requests are treated in completely separate ways.

CHARACTERISTIC OF THE WPS QUEUE

Each WPS queue is defined with:

• Its associated priority Pi

• Its queue size Ni, the maximum number of WPS call requests (of priority Pi or

higher) which can be queued simultaneously




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• Its own T11 timer value, which represents the maximum time a WPS call

request of a given priority Pi can remain in queue

The priority Pi is received from the MSC in the assignement request message.

The size Ni of a given WPS queue is set according to the allocWaitThreshold parameter. Inorder to be in accordance with the WPS industry requirement and configuration, each queue

size threshold Ni (with 8< i <12) should be equal (N8=N9=N10=N11=N12) and equals the

maximum number of WPS requests allowed in the WPS queues.

The timer T11 for a given queue can be defined with the allocPriorityTimers parameter. It is

understood that the request will immediately be denied with a cause “no radio resource

available” if this timer is set to “0”.

PROCEDURE TO QUEUE SERVICE REQUEST USER WPS

FIRST CASE: MS IS PUT IN QUEUE

As no radio channel is available, and as the queue size threshold Ni of the queue

corresponding to the WPS priority Pi is not reached, the WPS call request is put in queue i. A

queuing indication message is sent to the MSC.

SECOND CASE: MS IS DENIED (QUEUE FULL)

As no radio channel is available, and as the queue size threshold Ni of the queue

corresponding to the WPS priority Pi is reached, the WPS call request is denied. An

assignement failure message with cause “no radio resource available “is returned to the MSC.

THIRD CASE: MS IS PUT IN QUEUE TAKING THE PLACE OF AN OTHERMS

As no radio resource is available, if the queue size threshold Ni corresponding to the WPS

priority Pi is not reached, but if adding the call request to queue i would cause the threshold Nj

of another internal WPS queue j to be violated, and if the WPS request priority (Pi) is higher

than at least one WPS request (Pk) already in queue in the cell, the BSS takes the following

actions:

• the BSS shall remove the WPS request with the lowest priority (Pk) and the

most recent initiation time from the queue. It sends an assignment failure forthis removed WPS request with the cause “no radio resource available”.

• the BSC shall place the newly arrived WPS request in the queue i according

to the initiation time and the priority level.

A queuing indication for the WPS call request of priority Pi and an assignement failure for the

WPS call request of priority Pk are sent to to the MSC.




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MANAGEMENT OF SERVICE REQUEST USER WPS PUT IN QUEUE

RESOURCE AVAILABLE

If a radio traffic channel becomes available when there are WPS requests in queue, the

process of ressource allocation decribed in the WPS – Public access bandwith protection

(see chapter WPS – Public access bandwith protection below) has to be followed.

T11 EXPIRY

If the WPS request is in queue i for a radio traffic channel and the maximum time allowed for

that queue expires, the WPS request is removed from the queue and the call is cleared. A

clear request with the cause “no radio resource available” is then sent to the MSC.

RADIO CONTACT WITH THE MS IS LOST

If the WPS request is in queue for a radio traffic channel but radio contact with the mobile is

lost (detected by the BTS which informs the BSC), the WPS request is removed from the

queue and the call cleared. A clear request with the cause “Radio Interface Failure” is sent to

the MSC.

MS DISCONNECTS THE CALL

If the MS decides to disconnect the call while the WPS request is queued, the BSC receives a

clear command message from the MSC and processes the release of the call including the

request removing from the WPS queue.

FEATURE ACTIVATION

If the bscQueuingOption parameter is set to “not allowed” then queuing is not performed, i.e.

no request goes into any of the queues 0 to 12, whatever the wPSManagement value is. In all

the following cases, the bscQueuingOption flag is considered as “allowed (MSC driven)”.

One has to well understand the two levels of queuing in “MSC Driven” queuing mode:

• At the MSC level the call request is described by two fields in the assignement

request message: “queuing allowed” set to allowed / not allowed, and “priority

level” (14 are defined)

• At the BSC level the queuing management of the call requests is set to

allowed, so the BSC takes into account the 2 fields described above

WPS queuing is so done according both to the “queuing allowed” field value set in the

assignment request message sent by the MSC (if this field value is set to “queuing not

allowed”, then there is no queuing) and the WPS priority (1 to 5).

In all the following cases, this field value is considered as “queuing allowed” for all WPS and

public call requests.

WPSMANAGEMENT FLAG IS ENABLED

The WPS request is queued according to the mapping (GSM 08.08 priority / internal priority)

done by the customer at the OMC-R.




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Internal priorities correspond to the queues 0 to 7 for public requests, and queues 8 to 12 for

WPS requests.

When the wPSManagement flag is enabled, a recommended mapping of the allocPriorityTable

has to be respected.

When the wPSManagement flag is turned on, it also enables the PURQ AC algorithm feature.

(see chapter WPS – Public access bandwith protection below)

WPSMANAGEMENT FLAG IS DISABLED

It is recommended that the customer sets the mapping (GSM 08.08 priority / internal priority)

at the OMC-R, so that only internal priority 0-7 are used when the wPSManagement flag is

disabled. In this case, if a WPS request is received by the BSC, the request will be managed

like a public call since it will be queued in the public queues.

If no mapping is specified by the customer, the default mapping is done to the internal queue

0.

4.23.3 WPS – ACCESS CLASS BARRING WITH CLASS PERIODICROTATION

In normal conditions, the number of WPS Users should be sufficiently small that there is little

likelihood of them having a significant impact on public use. But in case of exceptional events,

the number of initial access is dramatically increased and can induce a full blocking of the

system.

In V9, a feature called "access class barring" was designed in order to avoid this kind ofproblem, thanks to a dynamic barring of a significant part of users. An enhancement of this

feature has been designed, in order to allow users to access periodically to the network,

without huge network congestion.

To synthesize, one can say that this feature allows users to access the network periodically

during network congestion by modifying the number of barred access classes in function of the

congestion state of the cell, and by periodically changing which access classes are barred.

There are no specific access class parameters that can be tuned in order to optimize WPS

use.

For further details about this change of access class baring, see chapter Barring of access

class.

4.23.4 WPS – PUBLIC ACCESS BANDWITH PROTECTION

The public access bandwidth protection is required in case of cell congestion with WPS users

in the cell. Assuming that the number of WPS users is less important than public users, and

taking into account that WPS users are priority users, this feature ensures that a radio network

bandwidth is available to public users during cell congestion (lack of radio resources).




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PRINCIPLE

The idea of the algorithm is to allocate a specified portion of the traffic channels (as they

become free) with preference to public calls, and to allocate a second portion of the traffic

channels (as they become free) with preference to WPS calls.

The BSC radio resource allocator processes the algorithm which favors WPS calls 1 out of

wPSQueueStepRotation times and then process the algorithm which favors public calls P out

of wPSQueueStepRotation times (P = wPSQueueStepRotation – 1).

With this choice, 1 out of wPSQueueStepRotation of the call capacity can be allocated for

WPS users, wPSQueueStepRotation being 1,2, …,10. (recommended value is 4 and hence

25% can be allocated with preference to WPS requests)

PURQ-AC ALGORITHM WITH SUPERCOUNT

PURQ-AC stands for Public Use Reservation for Queuing - All Calls

This algorithm is only activated if If the wPSManagement flag (BSC level) authorizes the WPS

requests management

When the algorithm is turned on (i.e at the startup of a BSC or after a lock/unlock of the cell),

the priority is given to a WPS call request (1 out of wPSQueueStepRotation times), the

algorithm proceeds to some checks about the state of the WPS queues (left side on the

schema below), then the priority is given to public call requests (P out of

wPSQueueStepRotation times) and the algorithm proceeds also to some checks about thestate of the WPS queues (right side of the schema below).

The aim of the supercount is to allow “10 call running deficit” over allocation, and enhanced

small cell performances. It smoothes out short term variations, and decreases delay. The

Supercount tigger value of 10 is a fixed value. Supercount is initialised to 0 and is reset to 0

when a lock/unlock action is done on the cell for instance.

FEATURE ACTIVATION

If the wPSManagement flag (BSC level) is disabled but queuing indications in the assignement

request message still give the priority to WPS call requests, in case of cell congestion, theWPS users may use all the cell bandwidth (due to their priority) and public users may not have

an access to the network. However that case could only occur if WPS queues are mapped on

internal queues 0-7 instead of the queues dedicated for WPS, because only internal queues 0-

7 are evaluated to serve a queued request when wPSManagementFlaf is turned off. The new

algorithm has a cell based internal management that does not impact any other cells in term of

traffic management.

This feature is linked with the queuing management (public and WPS requests) and hence

parameters related to the queue management have to bet set in order to take advantage of

the benefits provided by the PURQ AC algorithm.




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4.24. SATELLITE ABIS INTERFACE

The use of Satellite Abis links will be possible to allow the connection between BSC and BTS.

In some network areas, there is no earth terrestrial transmission infrastructure between the

BSC and the BTS. This feature solves this problem thanks to a satellite link between these 2

nodes.

To get detailed information about the implementation of this feature, please refer to document

[R31].

More details on recommended parameter associated to feature restrictions are given in the

Satellite Abis Interface - Engineering Guideline (refer to document [R32])

BSCBTS

Abis

Abis

Agprs

Ater BTS

Abis

BSCBTS

Abis

Abis

Agprs

Ater BTS

Abis




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4.25. NETWORK SYNCHRONIZATION

4.25.1 GLOBAL DESCRIPTION

ASYNCHRONOUS NETWORK

When NW synchronization is not applied (asynchronous network), cells get their time base

through the PCM time. As PCM of different cells are not correlated, it can be considered that,

comparing to the hypothetical network time reference, the not co-site cells have on a site

basis:

• Random time bit offsets (from 0 to 156,25)

• Random time slot offsets (integer from 0 to 7)

• Random frame numbers offsets (integer from 0 to 2 715 647).

Consequently, as shown in the figure below, between two not co-site cells there are random:

• Δtime bit offsets

• Δtime slot offsets

• Δframe numbers offsets

General case of non synchronization

It has to be noted that a MS computes - using its timebase counter - the time offset by

measuring the time from the beginning of TS0 on its BCCH carrier and the beginning of the

first TS0 on a neighbor BCCH carrier. Also, the data found on these 2 TS0 may be used for

calculating the FNOffset between its cell and the neighbor cell.

7

FN x-1

0 1 3

FN x FN x FN x

4

FN x

5 6

FN x FN x

5

FN x-1

6

FN x-1

0

FN y

1 2 3

FN y FN y FN y

4

FN y

5 6 7

FN y FN y FN y

7

FN y-1

cell 1

cell 2

Δ time bit offset (random)

Δ time slot offset

(random)

Δ frame number offset = y-x

(random)

7

FN x-1

0 1 3

FN x FN x FN x

4

FN x

5 6

FN x FN x

5

FN x-1

6

FN x-1

0

FN y

1 2 3

FN y FN y FN y

4

FN y

5 6 7

FN y FN y FN y

7

FN y-1

cell 1

cell 2

Δ time bit offset (random)

Δ time slot offset

(random)

Δ frame number offset = y-x

(random)




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Consequently, see general case of synchronization figure on previous page, between two not

co-site burst synchronized cells there are:

• Δtime bit offsets = 0• Random Δtime slot offsets

• Random Δframe numbers offsets

As in the case of an asynchronous network, the co-site cells have the same time bit offsets,

time slot offsets and frame number offsets.

TIME SYNCHRONIZED NETWORK

In a time synchronized network, it can be considered that, comparing to the hypothetical

network time reference, the not co-site cells have on a site basis:

• Time bit offsets = 0

• Known & controlled time slot offsets

• Known&controlled frame numbers offsets

Also, similar to the asynchronous network, the co-site cells have the same time bit offsets,

time slot offsets and frame number offsets.

Consequently, see general case of synchronization figure on previous page, between two not

co-site time synchronized cells there are:

• Δtime bit offsets = 0

• Known & controlled Δtime slot offsets• Known&controlled Δframe numbers offsets

It has to be noted that the main difference between a time synchronized and a burst

synchronized network is that time slot offset planning and frame number offset

planning are possible only in a time synchronized network.

4.25.2 FEATURE ACTIVATION

The parameters related to tune the feature are the following:

• btsSMSynchroMode

• tnOffset,

• fnOffset

• masterBtsSmId

Note: Other network existing parameters may have a significant impact on network

performances when network synchronization is applied:

• baseColourCode TSC (TSC=BCC) planning and therefore whole BSIC (NCC&

BCC) planning.




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• Hopping laws parameters (HSN, MAIO, MA list)

• dARPPh1Priority

Also, it has to be noted that more parameters (for handovers, location services etc…) may

have to be eventually retuned for an optimal functioning when network synchronization feature

is deployed.

4.25.3 FEATURE IMPACTS EXPECTATIONS

Network synchronization simple deployment may have positive impact on location services as

the location precision will improve with a better synchronization of the network elements.

However, synchronizing all BTS in a network, meaning synchronizing interferers and their

victims, doesn’t provide alone any gain of RF quality or RF capacity. On the contrary, thenetwork synchronization may degrade the network RF performances if no additional feature or

engineering solution is applied. (The main degradation is mainly due to the eventual TSC

collisions if a traditional BSIC -NCC/BCC- planning as for an asynchronous network is used)

Therefore, for improving the RF quality and capacity, a network synchronization deployment

must be accompanied by additional features and significant engineering parameter planning.

Please refer to chapter Network synchronization engineering planning methodologies.

After Activing NW synchronization significant modifications of the NW behavior may occur at

various levels:

• Quantity of interferences:

being able to control cell FN Offsets, it may be possible to use some

carefully chosen of hopping laws (HSN, MAIO, MA list, FN) in order to

decrease the collision probability between one or more couples of cells

being able to control cell TN and FN Offsets, it is possible to completely

avoid the collisions between two cells which are not co-site when using a

fractional reuse frequency plan

Note: all this eventual control of the quantity of interferences is possible only

when time synchronizing the network as it is required to control and plan the

FN Offsets (and TN Offsets as well);

• Impact of interferences:

the various features of interferences cancellation and noise cancellation for

both BTS and MS are expected to work optimally (or better) when

synchronizing the network

• Others

HO reactivity, LCS precision …

Please refer to Network Synchronization handbook [R34] for a complete Impact, engineering

rules and KPI Results presentation.




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4.26. NOVEL ADAPTIVE RECEIVER

4.26.1 PRINCIPLE

This v17.0 feature introduces a novel digital processing approach developed by Nortel

Networks for improving reception performances of GSM and EDGE radio communications. It

has been developed to enhance performances in real radio conditions (multipath profiles), with

a particular focus on interference from other radio channels (a major cause of disturbance for

reception performances).

Usual reception schemes are optimal under one specific noise assumption only, basically

thermal noise. However, digital communication faces in practice other noise sources, namely

adjacent channel and/or co-channel interferences, the statistics of which strongly differ from

thermal noise. The consequence is lower reception performances in presence of interferers,

leading to a poorer speech quality or lower throughput for the end-user. The approach

developed by Nortel consists in a scheme that adapts itself to the interference condition

affecting each received burst. In addition, a new filter design strategy has been developed in

order to come out, for each basic noise situation, with a filtering process yielding the minimal

BER.

This new method calls, prior to processing the burst, for an estimation of the noise situation.

This is achieved by a filter bank detector for the adjacent interferers; co-channels interferences

are taken into account later on, after channel sounding. According to the adjacent interference

noise estimated by the detector, a filter matching the noise situation is designed and applied to

the current burst.

Reception performance is significantly improved in most situations, especially with adjacent

interference conditions.

These benefits apply both to GMSK and 8PSK modulations, traffic and data applications. It

thus provides the end-user with an increased throughput for data transmission as well as an

improved quality of service for voice calls.

For more details, please refer to the Functional Note ([R45]).

4.26.2 HW/SW DEPENDENCE

This feature is applicable to :

• Hardware : BTS 6000/BTS18000 Radio Modules, 1900 MHz band only

• Software : v17.0 release.

4.26.3 ACTIVATION GUIDELINES

O&M PARAMETER

adaptiveReceiver is a new Class 2, transceiver object, parameter that serves to activate or

deactivate the Novel Adaptive Receiver. It can take two values :




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• “enabled” : use of the Novel Adaptive Receiver

• “disabled” : use of the legacy signal processing

RECOMMENDATIONS

HILLY TERRAIN PROFILES

For cells operating under very specific radio conditions, namely hard Hilly Terrain profiles, the

Novel Adaptive Receiver structure may possibly cause a slight performance loss compared

with the initial processing. Therefore, it is recommended to disable the adaptive receiver for

these cells. :

adaptiveReceiver = disabled

INTERWORKING WITH RX DIVERSITY

If Rx diversity is used, best receiver performance is achieved by activating both Joint diversity

and Novel Adaptive Receiver features :

adaptiveReceiver = enabled; diversity = enhancedDiversity.

INTERWORKING WITH EXTENDED CELL

Novel Adaptive Receiver does not interwork with the Extended Cell feature.

Therefore, for extended cells, the Novel Adaptive Receiver must be deactivated :

adaptiveReceiver = false.




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4.27. A5/3 ENCRYPTION ALGORITHM

4.27.1 PRINCIPLE

For details, please refer to the Functional Note ([R41]).

PURPOSE OF THE FEATURE

Before v17.0, the only available encryption algorithms available in the BSS were :

• No encryption

• Encryption algorithm version 1, also called A5/1

• Encryption algorithm version 2 (also called A5/2). A5/2 was removed from the GSM

networks at the end of 2006 in compliance with the 3GPP recommendations, as a

consequence of the published attacks against A5/2.

This v17.0 feature provides a new encryption algorithm in the BSS called A5/3.

Also, this feature changes the class of the existing parameter encryptAlgorSupported from

class 0 to class 3 to limit service disruption when changing its setting.

A5/3 ALGORITHM OVERVIEW

The A5/3 algorithm is stream cipher that is used to encrypt/decrypt blocks of data under a

confidentiality key Kc. The algorithm is based on the KASUMI algorithm, which is specified in3GPP TS 35.202. KASUMI is a block cipher that produces a 64-bit output from a 64-bit input

under the control of a 64-bit ciphering key.

4.27.2 HARDWARE DEPENDENCE

A5/3 is supported on :

• DRX ND3

• eDRX

• RM.

4.27.3 CIPHERING ACTIVATION RULES

BSS PARAMETERS

ENCRYPTION ALGORITHM ACTIVATION

The BSS can select A5/3, on MSC request, for a call, assuming that :

• A5/3 is supported by the TRX

• A5/3 is supported by the mobile




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• A5/3 is configured at the O&M level as the preferred encryption algorithm in the BSS

Since the A5/3 encryption algorithm is neither supported by all types of TRX nor by all

mobiles, and more especially by legacy mobiles already deployed by the operators, a fallback

encryption algorithm needs to be available whenever the A5/3 encryption algorithm is

requested by the MSC. In such a case, based on the value of the O&M parameter

encryptAlgorSupported , either “no encryption” or “A5/1” may be defined at O&M level as the

fallback encryption algorithm to be used by the BSS.

The encryptAlgorSupported parameter is an existing parameter which has been modified in

v17.0 as follows :

• The class is changed in v17.0 from class 0 to class 3. Thus, no BDA build is

necessary when changing the value of this parameter : no interruption of service

• The range of values has been expanded and now includes the following values :

o “None” : the BSS will not cipher any calls

o “gsmEncryptionV1” : all the BTS of the BSS will use A5/1 for ciphering, if

requested and allowed by the NSS

o (new value) “gsmEncryptionV3FallbackNoEncryption” : A5/3 is the preferred

algorithm for the BTSs of the BSS, but if this algorithm cannot be used for a

specific call in a specific cell (due to mobile capability limitation or TRX

capability limitation or MSC request), the BSS will not cipher the call

o (new value) “gsmEncryptionV3FallbackV1” : A5/3 is the preferred algorithm

for the BTSs of the BSS, but if this algorithm cannot be used for a specific callin a specific cell (due to mobile capability limitation or TRX capability limitation

or MSC request), the BSS will attempt to use A5/1 instead.

BSSMAP MESSAGES CONFIGURATION PARAMETERS

With a Nortel BSS supporting the A5/3 feature, the NSS must be able to understand ciphering

information fields conveyed by the BSS to the NSS in the following BSSMAP messages :

• CIPHER MODE REJECT

• ASSIGNMENT COMPLETE

• HANDOVER PERFORMED

• HANDOVER REQUEST ACKNOWLEDGE

• CIPHER MODE COMPLETE.

Today (2007), all NSS software on the market supports these messages. Therefore, these

BSSMAP messages and fields must be enabled on the BSS side, otherwise the BSS will not

send them to the NSS, and this risks causing the ciphering procedure to operate in a less-

than-optimal manner.

To prevent this happening, the following BSS parameters must be set to value “true” :

• cypherModeReject




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• encrypAlgoAssComp

• encrypAlgoCiphModComp

• encrypAlgoHoPerf

• encrypAlgoHoReq

• layer3MsgCyphModComp

NSS PARAMETERS

A5/3 is supported by the NSS Nortel since GSM07 by feature AD8028.

A5/3 is datafilled in the MSC by setting the following Office Parameters :

• GMSC_CIPHERING (OFCOPT table) : enables ciphering and deciphering of the radio

interface control between the MSC and the radio network subsystem (RNS) for the

transmission of user data or confidential network parameters.

• GSM_CIPHER_ALGORITHM_SUPPORTED” (OFCENG table) : indicates which GSM

ciphering algorithms are supported, in addition to the “no” encryption option. There are

seven defined algorithms (A5/1, A5/2, A5/3, A5/4, A5/5, A5/6, and A5/7).

4.27.4 PERFORMANCE IMPACT

BTS PROCESSING TIME

The ciphering processing time of the A5/3 encryption algorithm is not degraded compared to

the A5/1 processing time inside the BTS.

CALL SETUP TIME

On the other hand, since the “ciphering mode setting field” may be included in the Radio

Interface ASSIGNMENT COMMAND message, adding 1 byte, the BSS may need to send an

additional frame on the radio interface SDCCH channel in case the existing frame is already

full without this field. This additional frame could lead to 235 ms additional delay at the call

setup.

HANDOVER DURATION

In the same way, since the “ciphering mode setting field” may be added in the Radio Interface

HANDOVER COMMAND message, adding 1 byte, the BSS may need to send an additional

frame on the radio interface dedicated channel in case the existing frame is already full without

this field. This additional frame could lead to 235 ms (handover on SDCCH) or 20 ms

(handover on TCH) additional delay during the handover.




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4.28. BTS SMART POWER MANAGEMENT

4.28.1 DEFINITIONS

Several definitions will be used in this section :

• Configured TRX : TRX that is mapped to a TDMA. The state of a configured TRX’s PA

depends on whether the TRX is active or idle (see definitions below) and on the

circumstances.

• Unconfigured TRX : transient state of the TRX that exists while the TRX has not yet

received the “current cell parameters” from the BTS

• Deconfigured TRX : state of a TRX that exists after having received a “clear config”

command from the BTS

• Spare TRX : TRX that is not mapped to a TDMA. The PA of a spare TRX may be in

state “ON” or state “OFF” depending on the circumstances, as explained in what

follows.

• Active TRX : configured TRX that is being used by signaling or traffic on at least one

of the TDMA’s radio timeslots. The PA of an active TRX is always “ON”.

• Idle TRX : configured TRX whose TDMA is not currently carrying any ongoing traffic or

signalling. The PA of an idle TRX may be in state “ON” or state “OFF” depending on

the circumstances, as explained in what follows.

4.28.2 PRINCIPLE

This feature permits to reduce BTS power consumption by automatically switching the PA off

when no circuit communication is on-going.

On BTS 18000 family, the PA can be switched OFF or ON thanks to an electronic

switch. This switch can be set to ON or OFF by software, thanks to a dedicated new

TX firmware function.

On S8000 and S12000 BTS, the PA RF part can be switched OFF or ON thanks to a

firmware command.

PA switching off can be managed in two different ways, depending on RM hardware:

• Regular smart power management feature: the PA is switched off when no circuit

communication is on-going on the TRX for a configurable time. PA is automatically

switched on as a circuit communication establishment begins

• Enhanced smart power management feature: the PA is switched off per timeslot

when there is nothing to be emitted for the timeslot.

Enhanced smart power management is only available for BTS 18000 families on RM

equipped with PA Andrew. It is not available on RM equipped neither with PA

Powerwave nor on BTS S8000 or S12000.




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When the TRX receives the current cell parameter message activating smart power

management, it activates either “regular” or “enhanced” feature depending on type of

activation requested by the operator.

If enhanced feature is requested on a non compatible PA hardware, regular feature is

activated by the TRX in place. When enhanced feature is activated, the “timing before

PA switching OFF” parameter is ignored by the TRX.

• On BTS 18000 family, if the RM is equipped with PA Andrew, both regular and

enhanced features are supported.

• On BTS 18000 family, if the RM is equipped with PA Powerwave, only regular

smart power management is supported.

• On BTS S8000 and S12000, only regular smart power management is supported.

Note:

• For BTS 18000 families, if some RM is equipped with PA Andrew and

other are equipped with PA Powerwave, enhanced feature can be

activated on RM with PA Andrew, while regular feature is activated on

RM with PA Powerwave.

• If enhanced feature has been requested at MMI on a non compatible

PA, the BTS does not notify the OMC that regular feature has been

actually activated on the TRX in place.

• The "enhanced" feature behavior is not compatible with the PA

Powerwave switching time; this is the reason why it is only availableon RM with PAs Andrew.

4.28.3 BTS BEHAVIOR BEFORE FEATURE INTRODUCTION

Before v17.0, the BTS behaviour is the following:

When the TRX restarts (BTS start up, TRX lock/unlock, TRX trap …) the PA is in an un-

powered state. It remains un-powered until it has received an RF Trans message from the

BSC.

Once the PA has been powered on, it remains so until the next reset or lock of the TRX.

This behaviour applies to all TRX regardless of their state:

• configured TRX (by definition, a configured TRX is mapped to a TDMA),

• spare TRX (by definition, a spare TRX is not mapped to a TDMA)




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4.28.4 REGULAR SMART POWER MANAGEMENT BEHAVIOR

FEATURE DEACTIVATED

CASE OF CONFIGURED TRX

In v17.0, if the feature is deactivated, the TRX behaves as before v17.0.

CASE OF SPARE, UNCONFIGURED OR DECONFIGURED TRX

The feature cannot be activated on a spare, unconfigured or deconfigured TRX. However, the

behaviour has been modified between v16.0 and v17.0 so that a spare or unconfigured or

deconfigured TRX is systematically switched off after a certain time For this, a 30 second

internal timer is started when the “enable TRX procedure” (RF Trans un-configuring) is

performed. When this timer expires, if no TDMA has been configured on the TRX, the PA is

switched off and its display hardware state is set to “OK – OFF cause

SmartPowerManagement”

As soon as the TRX is configured with a TDMA, this PA will be switched on.

FEATURE ACTIVATED

CASE OF TRX CONFIGURED WITH SPECIFIC TDMA

The TRX that are mapped to specific TDMA configurations are not allowed to turn off their PA.

The feature, even if it is activated, does not apply to them. These TDMA configurations are the

following:

• TDMA containing a BCCH channel

• TDMA containing a combined BCCH/SDCCH channel without CBCH

• TDMA containing a combined BCCH/SDCCH channel with CBCH

• TDMA containing a non-combined SDCCH/8 channel with CBCH channel

• TDMA containing a pDTCH channel

ALL OTHER CASES OF CONFIGURED TRX

For all other configured TRX whose TDMA is not in one of the above categories, if the feature

has been activated, the TRX automatically switches its PA OFF after the TDMA has been idle

a certain amount of time (configurable timer). The TRX switches its PA on again when a

channel is activated on the TDMA for a circuit-switched call establishment or for an incoming

handover.




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More precisely :

• when the BTS receives a channel activation message from the BSC :

o If the PA had been switched off, it is switched back on. PA hardware state is

set to OK (or KO).

o If the PA is still on but the TRX is idle, meaning that the smart Power Switch-

Off timer is running, then this timer is immediately stopped.

• when the BTS receives a channel release message from the BSC : if there are no

more ongoing circuit-switched calls on the TRX (TRX has become idle), the

countdown of the smart Power Switch-Off timer is started.

The fact that the PA is switched off has no impact on the TRX operational state : the TRX

remains in the “in service” state.

The PA switching off has no impact on the TRX receive chain.

CASE OF SPARE TRX

The feature does not operate on a spare, unconfigured or deconfigured TRX, even if the

feature is activated on the cell.

However, the behaviour has been modified between v16.0 and v17.0 so that a spare,

unconfigured, or deconfigured TRX is systematically switched off, regardless of the activation

or deactivation of the smart power management feature. For this, a 30-second internal timer is

started when the “enable TRX procedure” (RF Trans un-configuring) is performed. When this

timer expires, if no TDMA has been configured on the TRX, the PA is switched off and itsdisplay hardware state is set to “OK – OFF cause SmartPowerManagement”

As soon as the TRX is configured with a TDMA, it ceases to be a spare, unconfigured or

deconfigured TRX and its PA will be switched on.




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4.28.5 ENHANCED SMART POWER MANAGEMENT BEHAVIOR

Once the “enhanced” feature has been activated, the PA is switched off as soon as there is

nothing to emit during at least two consecutive Timeslots. It is switched on as soon as somesignal has to be sent again.

There is no signal to emit on one timeslot in the two following cases:

• No communication is on-going on the timeslot,

• One communication is on-going on a TCH timeslot but the communication is on DTX

(during silence, no signal is emitted). It is considered that a communication is on DTX

during 50% of the time.

TCH timeslot may be switched off during DTX period while a communication is on-going.

At reception of current cell parameter message activating the feature, the RM (with PA

Andrew) applicative software activates the enhanced feature in the firmware. The PA

switching off and switching on are then managed by the firmware this way:

The firmware knows two timeslots in advance if there is some signal to emit or not.

If nothing has to be emitted (for at least two consecutive TS), the firmware switches the PA off

at the beginning of the first “idle” timeslot. Once PA is switched off, when there is some signal

to emit again, the firmware switches the PA on one timeslot in advance, so that the PA is

switched on at the beginning of the timeslot to emit.

As a consequence, if there are N consecutive idle timeslots, the PA will be effectively switched

off during N-1 timeslots. PA can only be switched off if there are at least 2 consecutive idle

timeslots. It is called “timeslot switching off”.

As PA switching off and on is managed per Timeslot when there is some signal to emit or not,

the enhanced feature can be activated on all the TDMA, whatever the type of channels

configured on the TDMA. BCCH and combined BCCH TDMA will never be switched off

because its Timeslots are never idle; TRX supporting combined BCCH, SDCCH/8 used for

CBCH or PDTCH channel will switch its PA off when there are idle timeslots.

4.28.6 HARDWARE DEPENDENCE

This feature is applicable to RM family only.

4.28.7 ACTIVATION GUIDELINES

O&M PARAMETERS

ACTIVATION PARAMETER

This feature is activated thanks to a BSS parameter called smartPowerManagementConfig :




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• Class 3

• object : powercontrol

• range : “disabled”; “enabled”; “enhanced”;

POWER SWITCH-OFF TIMER

Once the regular feature has been activated, when the TRX has detected its PA has to be

switched off, it is not done immediately but after a “confirmation time” configured at the OMC.

Once the enhanced feature has been activated, the PA is switched off as soon as there are

two consecutive idle timeslots; no timer is managed in that case. When enhance feature is

active no timer is started or stopped until the feature is deactivated.

When it is used, the “confirmation time” is managed thanks to smartPowerSwitchOffTimer

• Class 3

• Object : powercontrol

• range : 5 to 255 minutes

At TRX start up it is initialized at 30 s default value. It is set to smartPowerSwitchOffTimer at

reception of regular feature activation (current cell parameter message, if feature can be

activated on TDMA). It is set to non significant value at reception of enhanced feature

activation.

It is reset to 30 s default value at TRX reset, and at clear config.

RECOMMENDATIONS

CONFIGURATION OF LOGICAL CHANNELS ON TDMA

At radio TS configuration, if BCCH, combined BCCH (and SDCCH/4 or not), SDCCH/8 used

for CBCH channel, or PDTCH channel is configured on the TRX, the regular feature cannot be

activated on the TRX. Enhanced feature can be activated on any type of TDMA.

, As TDMAs that carry BCCH, SDCCH or pDTCH are never switched off when using regular

feature it is recommended to collect these channels as far as possible on the same TDMA

rather than spread them onto several TDMAs or not to configure more pDTCH than are strictly

necessary.




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MINIMUM TIMER VALUE

On BTS family 1800 (without the feature), if there is no call on a TRX for 5 minutes at least,the VVA consign of the PA is reduced by 2 dB.

The aim is to avoid untimely a “high current” alarm when the PA starts transmitting again after

a while without transmission. Such an alarm could occur if the PA gain, which depends on the

VVA consign, is not consistent with the “new” temperature of the PA when it starts transmitting

again (temperature goes down when PA stops transmitting).

With the “smart power management” feature activated, the temperature will fall all the more

as, on top of not transmitting, the PA is actually completely switched off. Moreover, this “off”

state may last the whole night causing even further temperature drop.

Therefore, before a PA is switched off, it is vital that the VVA consign should have been

reduced by 2dB so that when the PA is switched back on again, there are no high current

alarms. To ensure this VVA is reduced by 2dB, as explained above, 5 minutes must elapse

after the last call on the TDMA has been released. If the smart power timer is less than 5

minutes, the PA would be switched off before a VVA consign reduction cpuld be applied. So,

when the PA is switched back on again, it will apply the old consign corresponding to a high

temperature, whereas the PA will have significantly cooled down. This risks triggering an

alarm ans dpossibly damaging the PA.

To prevent this, the smart power swicth off timer minimum value has, by design, been set to 5

minutes.

In case enhanced feature is active, if the PA is switched on then off in the same frame,temperature variation will be low enough to remain compatible with current VVA consign. We

consider this is true even if PA remains completely OFF during 5 minutes. Beyond 5 minutes

off, VVA consign will be “automatically” reduced.

This doesn’t apply to S8000 or S120000 BTS whose power loop behavior doesn’t need such

attenuation.

OPTIMUM TIMER VALUE

When regular smart power management is used, the smaller the switch-off timer :

• the more reactive the power management will be to the minute-by-minute changes to

the call profile as the day progresses towards quieter moments

• the more power is likely to be saved as a result.

• but the more frequently the PA is likely to go through off/on cycles, especially at the

transition from busy hour to quieter hours, thus possibly impacting its life expectancy.

Furthermore, the more TRX per cell, the more TRX are eligible for switch-off, and therefore the

more the feature is expected to make a difference to the power consumption.




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4.29. EVEA: ENHANCED VERY EARLY ASSIGNMENT

4.29.1 PRINCIPLE

When a mobile initiates an access to the network, the BSC allocates a SDCCH channel. Then,

according to the MSC request, the call stays on the signaling channel, or changes on a traffic

channel.

The BSC is able to allocate for signalling purpose a TCH channel instead of a SDCCH

channel, with the introduction of the feature “SDCCH overflow”. This feature is activated as

soon as there is no more SDCCH

Note: PDTCH can't be preempted to perform signaling, because of the timer in the mobile

which expire too quickly and requests a new channel.

The BSC is also able to allocate directly a TCH with a fall back with SDCCH, with the

introduction of “call reestablishment” feature. It is triggered when the establishment cause,

included in channel request message on Air interface, is set to specific cause. The NECI bit is

not used in current version limiting the possibility of using such a mechanism.

Indeed prior to V18, the following 2 processes were available:

EA: Early Assignment; GSM feature consisting to allocate a SDCCH during signaling phase

and then a TCH during speech/data phase.

VEA: Very Early Assignment; GSM feature consisting to allocate a TCH during signaling

phase.

In V18, EVEA: Enhanced Very Early Assignment feature consists mainly in broadcasting NECI

bit in system information so the BSC is able to analyze more accurately the mobile request.

Therefore, when there is no traffic load in cell : according to the type of communication

requested by the mobile in the channel request, the BSC shall allocate a TCH for a speech

call or a CS data call, and to keep SDCCH channels for procedures in signaling mode, like

location update, attach, detach, SMS in idle mode...

4.29.2 ACTIVATION

New parameters which manage the feature activation are:• EATrafficLoadStart

• EATrafficLoadEnd

• VEASDCCHOverflowAllowed




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The EVEA feature is activated as soon as the two new parameters EATrafficLoadStart and

EATrafficLoadEnd are both different from 100.

Note that if EATrafficLoadStart is equal to 100 and EATrafficLoadEnd is different to 100,

EVEA feature is activated.

The VEA allocation is activated until the traffic load in cell is high, and deactivated if the load

increases. To avoid ping pong effects, a hysteresis is managed:

Here below is the synthetic view

No traffic load Traffic load

EVEA deactivated

(v17 behavior) (*)

No SDCCH blocking VEA EA EA

SDCCH blockingVEA, SDCCH overflow if

allowedVEA, no SDCCH overflow EA, SDCCH overflow

(*) Whatever the traffic load

-

Max HR capacity

Max FR capacity

Traffic

24 hours

Time

Number of

allocated TCH

Full rate area-

Max HR capacity

Traffic

24 hours

Number of

allocated TCH

Full rate area

Max HR capacity

Max FR capacity

Traffic

Number of

allocated TCH

Full rate area

AMR HR based on traffic area

EATrafficLoadStart

EATrafficLoadEnd

VEA

VEA

EAEA

EA

VEA

HRCellLoadStart

HRCellLoadEnd

EA

EA EA

EA




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SDCCH BLOCKING

The SDCCH blocking cases are temporary and transitional.

To manage the SDCCH blocking, SDCCH overflow (i.e. allocating a TCH for signaling

call) is allowed:

• if there is no traffic load and,

• if the parameter VEASDCCHOverflowAllowed allows it.

The VEASDCCHOverflowAllowed allows or not to perform SDCCH overflow when

there is no traffic load but there is no more available SDCCH in cell. This parameter is

used only when EVEA is activated and doesn’t impact the actual behavior.

TRAFFIC LOAD

The Filtered TCH ratio used for AboT explained in is reused to evaluate traffic load

and compared to two thresholds:

IF EATrafficLoadStart and EATrafficLoadEnd are both different from 100

THEN

IF Filtered TCH ratio < EATrafficLoadEnd then the traffic is not loaded

ELSE IF Filtered TCH ratio ≥ EATrafficLoadStart THEN the traffic is loaded

ELSE no change

IF EATrafficLoadStart and EATrafficLoadEnd are both equal to 100

THEN

The EVEA feature is deactivated and so the V17 behaviour is kept

At the beginning, the traffic is considered as not loaded

Note : the case traffic load and SDCCH blocking may seem inconsistent but is in fact

is logical : if there is no more SDCCH available, no more signaling communication can

be established and a TCH signaling is used for speech communication (this is VEA

behavior).

CAUTION!

The explanation of the activation/deactivation VEA allocation, is that VEA allocation

may disturbs many features useful when the network is loaded (AMR Based on Traffic

or AMR Maximization features for instance).




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4.29.3 FEATURE INTERWORKING

EVEA feature disturbs the AMR feature because the AMR TDMA priority can't be

checked before allocating a TCH.

No specific allocation is performed during signaling phase; so, the classical allocation

algorithm is run (TS number, TDMA number, and level of interference).

If parameters are consistent, the EVEA feature is complementary with AMR

maximization, because the first one is used only when there is no load, while the

second is used when there is load.

• AMR BOT evolution: no impact.

• Direct HR allocation: no impact; the case TCH FR signaling to TCH HR

speech is already taken into account in EVEA feature.

• HR to FR handover deactivation: no impact; the BSC can’t allocate HR

signaling channel.

• All incoming handover forced to HR: no impact.

• Queueing HR: no impact.

If parameters are inconsistent, then EVEA disturbs ABoT & AMR maximization




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5. ALGORITHM PARAMETERS

5.1. INTRODUCTION

This chapter lists parameters, sorted according to their group, as they were defined in the

previous Chapter.

The following information is provided for each parameter:

• a brief description

• value range and unit

• the recommended value: takes the best benefit of the feature in a standard

network configuration and environment.

• process in which it is used (see Chapter 2)• some engineering rules that must be considered for the parameter setting

• the object that contains this parameter

• the default value. Most of the time, the default value inhibits the feature

characterized by this parameter

• corresponding GSM name

• GSM Recommendation

• parameter type and OMC-R class (see note below)

Note: The recommended value is established from Nortel experience and studies. This value

has to be adapted according to the network specificities. For the recommended value in GSM

900, it is the same value for eGSM and GSM-R when nothing else is recommended for these

two networks. This value is not contractual, and it could change with Nortel new studies results

and experience growth.

The following types of parameters can be distinguished:

• Customer engineering parameters:

Addressing: relative to an object

Design: contract characteristic

Optimization:network tuning

Operation: network operation

• Manufacturer parameters:

System: modifying such a parameter seriously impacts system

behaviour

Product: parameters related to the current system release

DP: stands for permanent data

OMC-R class gives rules to be followed when modifying a parameter:

CLASS Rules

Class 0 Implies reconstruction of the BDA

Class 1Put BSC out of service (i.e. BSC state set to “locked”), takes new parameters into account byresetting active chain and passive chains

Class 2 Declares the object (or its parent) temporarily out-of-service before modification

Class 3 Modification is dynamically taken into account




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5.2. 2G CELL SELECTION AND RESELECTION PARAMETERS

cellReselectHysteresis Class3 V7

Description: Hysteresis to reselect towards a cell:

when the MS is in IDLE mode and reselects a cell with a different

LA (Location Area)

when the MS is in GPRS STANDBY mode and reselects a cell with

a different LA (Location Area) or a different RA (Routing Area)

when the MS is in GPRS ready state and reselects a different cell

Value range: [0 to 14, by steps of 2] dB

Object: bts

Default value: 6 dB

Type: DP, Optimization

Rec. value: 6 dB (rural / low cell overlap), 10 dB (urban / high cell overlap)

Used in: Criteria for reselection towards a cell of a different Location Area(Sel_2)

Eng. Rules: GSM case:

A high value prevents the MS from making frequent location updatesand may also prevent an MS from performing adequate locationupdates, thus risking not receiving calls. The level variation of thesignal is more important in an urban context, so a higher value ofhysteresis should be set. To avoid frequent location updates, there isalso a timer forbidding the reselection of the previous server cell. Fora reselection with change of location area, the value is 15 seconds.

GPRS case:In order to minimize the impact of the introduction of the GPRS in anexisting GSM network, it is recommended not to modify the currentvalue of CellReselectHysteresis used for voice. A high value wouldkeep the link for a long time hence some communications would havea high BLER due to an important load of the cell. The throughputwould then decrease because of the retransmission at RLC/MAClayer.On the other hand a low value would ease the cell reselection ping-pong in data mode which could severely decrease the overall userthroughput due to the gap of transmission during the reselection.

In case of cell overlap (i.e. urban environment, site covered in severalfrequency bands), 10dB should be considered in order to minimizeping-pong reselections.




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Eng. Rules: In GSM 900 & 850MHz, msTxPwrMax = msTxPwrMaxCCH. In GSM1800 or 1900, msTxPwrMaxCCH ≤ msTxPwrMax. Both are verified atOMC-R level. This value is related to typical mobile (handheld orvehicle-mounted) and assumed an environment (urban, rural). If thecell is rural, it is possible to put a higher value because lot of mobiles

have car kits (can transmit at a higher power). In urban environment,the density of mobile increases and care should be taken to reduceinterferences. Furthermore, the major part of the mobile market arehandsets.

Remark: If the cell is used as a neighbor cell of another serving cell in thenetwork, msTxPwrMaxCCH must be identical to the msTxPwrMaxCellpower defined for the corresponding adjacentCellHandOver object(the values must be checked by users).

penaltyTime Class 3 V8

Description: Timer used by an idle mobile before reselecting a cell (C2 criterion)

When a mobile places the cell on the list of strongest carriers, it startsa timer that stops after penaltyTime seconds. This timer is reset whenthe mobile removes the cell from the list.For the entire timer duration, the reselection criterion (C2) is assigneda negative temporaryOffset value.Refer to the cellReselectOffset parameter in the Dictionary.

Value range: [20 to 640, by steps of 20] seconds.

The value “640” is reserved and indicates that the temporary offset isignored in the reselection criterion (C2) calculation. It also changesthe sign in the C2 formula.

Object: bts

Default value: 20Type: DP, Optimization

Rec. value: 20

Used in: Additional reselection criterion (for phase 2) (Sel_3)

Eng. Rules: The longer this timer is, the longer a penalty is applied for reselectingthat cell. The value should be correlated with the expected mobilesspeeds, which are to be managed by that cell.




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rxLevAccessMin Class 3 V7

Description: Minimum signal strength level received by the mobiles for being

granted access to a cell. The information is sent to MS prior toregistering.

As an example, a threshold level of -104 dBm corresponds to anacceptable BER of approximately 10-2 (minimum recommendedvalue).

Value range: [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm

Object: bts

Default value: less than -110 dBm


Rec. value: GSM 900/GSM 850: -101 to -100 dBm,

GSM 1800/1900: -99 to -98 dBm

Used in: Selection or reselection between cells of current Location Area(Sel_1), Criteria for reselection towards a cell of a different Location Area (Sel_2), Additional reselection criterion (for phase 2) (Sel_3)

Eng. Rules: Main parameter for selection or reselection.

Notice that the tuning of this parameter strongly depends on theoperator strategy. Decreasing the value eases the access to thenetwork by reducing the quality. This parameter defines the cellaccess size.

Remark: The difference between GSM 900/GSM 850 and GSM 1800/1900 isdue to MS sensitivity (-104 dBm (GSM 900/GSM 850), -102 dBm(GSM 1800/1900)).

Example:

RxLevAccessMin 1 = -100 dBm

RxLevAccessMin 2 = -99 dBm A rough calculation gives the following impact on the cell accesssurface: Access Zone 1 = Access Zone 2 x 1.2

CAUTION! A very low value of RxlevAccessMin allows mobiles to camp andattempt calls. Most of calls attempts at very low field levels fail, or leadto a call drop a few seconds after the call has been established. Thisassessment is also true for GPRS/EDGE procedure, a verypermissive value of RxlevAccessMin leads to data establishmentfailure and TBF drop.




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temporaryOffset Class 3 V8

Description: Negative offset applied during Penalty Time for reselecting a cell (C2criterion)

This negative offset is applied during the entire penaltyTime durationand allows to prevent speeding mobiles from selecting the cell. Referto the cellReselectOffset entry in the Dictionary.

Value range: [0 to 70, by steps of 10] dB

Object: bts

Default value: 70


Rec. value: 0 (microcell & macrocell in mono-layer),

70 (macrocell in multi-layers)

Used in: Additional reselection criterion (for phase 2) (Sel_3)

Eng. Rules: The value prevents a mobile from reselecting a cell duringPenaltyTime. By giving the highest possible value, which is higherthan the field strength range (0 to 63), we ensure that the mobile willnot reselect the cell before the timer expires. Then, the value 70means the applied offset is infinite.

It could be dangerous on a microcell or macrocell in a mono-layerenvironment to have a high value, because it slows down thereselection process. However, on a macrocell in a multi-layersenvironment, it is recommended to prevent from reselecting a cell(value 70), in keeping a low value for “penaltyTime” (20 seconds).




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5.3. 2G-3G CELL RESELECTION PARAMETERS

3GTechnology Class 3 V17

Description: FDD or TDD 3G technology selection

Value range: FDD (0) /TDD (1)

Object: bts

Default value: FDD

Type: DP

Rec. value: Accordingly to the technology used for 3G

Used in: 2G - 3G Cell Reselection

Eng. Rules:

gsmToUmtsReselection Class 3 V14

Description: gsmToUmtsReselection is composed of 4 parameters:

3GsearchMinLevel

3GreselectionOffset

3GAccessMinLevel

3GReselectionARFCN

Object: bts

Type: DP

3GAccessMinLevel Class 3 V14

Description: A minimum threshold for Ec/No for UTRAN FDD cell re-selection(GSM spec 45.008 name for this parameter is FDD_Qmin)

Value range: [0: - 20 dB, 1: - 6 dB, 2: - 18 dB, 3: - 8 dB, 4: - 16 dB, 5: - 10 dB, 6: -14 dB, 7: - 12 dB]

Object: bts

Default value: - 12 dB

Type: DP

Rec. value: - 12 dB

Used in: 2G - 3G Cell Reselection Eng. Rules: below the recommended value UE may not be able to reach the 3G

network in good conditions.

Note: The SI2Quater message broadcasted by the BSS is an index [0 to 7]that is interpreted by the mobile depending on the release date of thatmobile:




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Index Mobiles’ interpretationbefore October 2003

Mobiles’ interpretationafter October 2003

0 - 20 dB - 20 dB

1 - 19 dB - 6 dB2 - 18 dB - 18 dB

3 - 17 dB - 8 dB

4 - 16 dB - 16 dB

5 - 15 dB - 10 dB

6 - 14 dB - 14 dB

7 - 13 dB - 12 dB

One should be advised that OMC-R may eventualy display “old”values while the offset is broadcasted.

3GReselectionARFCN Class 3 V14

Description: Neighbouring UMTS cell ARFCN. The BSS does not perform anycheck on UARFCN value so new UMTS frequency band introductionapplies to any BSC architecture.

(GSM spec 45.008 name for this parameter is FDD_ARFCN)

Value range: 0 to 16383

Object: bts

Default value: 0

Type: DP

Rec. value: a non-null value to broadcast the SI2Quater on the BCCH


Eng. Rules:

3GReselectionOffset Class 3 V14

Description: Applies an offset to RLA_C for cell reselection to access technology /mode FDD (GSM spec 45.008 name for this parameter isFDD_Qoffset)

Value range: [-∞dB, -28 dB, -24 dB, -20 dB, -16 dB, -12 dB, -8 dB, -4 dB, 0 dB, 4dB, 8 dB, 12 dB, 16 dB, 20 dB, 24 dB,28 dB]

Object: bts

Default value: -∞dB

Type: DP

Checks:

Rec. value: see Engineering Rules


Eng. Rules: that parameter allows a fine tuning in UMTS re-selection byintroducing a favorable/defavorable offset toward a UMTS cell.

The recommanded value by default is “0 dB”.




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3GSearchLevel Class 3 V14

Description: Search for 3G cell if signal level is below or above the threshold

(GSM spec 45.008 name for this parameter is Qsearch_I)

Value range: [0: “< -98 dBm”, 1: “< -94 dBm”, 2: “< -90 dBm”, 3: “< -86 dBm”, 4: “< -82 dBm”, 5: “< -78 dBm”, 6: “< -74 dBm”, 7: “Always”, 8: “> -78 dBm”,9: “> -74 dBm”, 10: “> -70 dBm”,11: “> -66 dBm”, 12: “> -62 dBm”, 13:“> -58 dBm”, 14: “> -54 dBm”, 15: “Never”]

Object: bts

Default value: -98 dBm

Type: DP



Eng. Rules: this parameter set whether UE should search for UMTS cells or not. It

can allow UE to search above a certain level, below a certain level, oralways. Note that in this last case the UE battery autonomy can beimpacted.




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5.4. LEGACY MEASUREMENT REPORTING PARAMETERS

powerControlIndicator Class 3 V7

Description: Whether MS signal strength measurements on the TCH or SDCCHshould include measurements on BCCH frequency or not.

Value range: [include BCCH measurements / do not include BCCH measurements]

Object: bts

Default value: include BCCH measurements


Rec. value: See Eng. Rules

Used in: Power Control Algorithms

Eng. Rules: Downlink measurements performed by the mobile on TCH or SDCCHshould not include measurements done when the channel frequencyis the BCCH frequency if the following two conditions are met:

The radio channel hops at least on two different frequencies, on of

which is the BCCH frequency.

Power control on the downlink is used.

CAUTION! This parameter is only relevant with BTS using cavity couplingbecause only cavity coupling allows to use BCCH frequency as part ofthe hopping frequency list. For BTS using hybrid coupling, the BCCHfrequency is never part of the hopping list, so this parameter isirrelevant in that case. See §4.5.9 for details.




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5.5. ENHANCED MEASUREMENT REPORTING PARAMETERS

fDDMultiratReporting Class 3 V17

Description: (applicable both to normal measurement reporting and EMR) Numberof UTRAN FDD cells to be reported by the mobile in the list ofstrongest cells inside the normal or Enhanced Measurement Reportmessage.

Value range: 0: “no UTRAN cell is favoured”

1: “1 UTRAN strongest cell is favoured”

2: “2 strongest UTRAN cells are favoured”

3: “3 strongest UTRAN cells are favoured”

Object: bts

Default value: 0


Rec. value: see Eng. Rules

Used in: Enhanced Measurement Reporting (EMR)

UTRAN cell reporting using legacy measurement reports (V17)

Eng. Rules: The value depends on the network operator strategy.

However, in case of HO2G-3G enabled with normal measurementreporting (EMR disabled), it is necessary to exercise caution whensetting the parameters fDDMultiRatReporting andmultiBandReporting. These parameters define the number of UTRANcells and non-serving band GSM cells, respectively, that must be

included by the mobile in the list of strongest cells in the measurementreport. Therefore it leaves (6 - fDDMultiRatReporting -multiBandReporting) spaces for the serving band GSM cells.Therefore, if EMR is disabled, it is recommended not to exceedfDDMultiRatReporting = 2 and multiBandReporting = 2.

fDDreportingThreshold Class 3 V17

Description: CPICH RSCP level measured on UTRAN cells, above which themobile shall apply a higher priority to UTRAN cells in the enhancedmeasurement report message

Value range: -115 dBm, -109 dBm, -103 dBm, -97 dBm, -91 dBm, -85 dBm, -79dBm, never

Object: handoverControl

Default value: never


Rec. value: -97 dBm


Eng. Rules: An operator willing to unload GSM network to UMTS network butkeeping calls in good conditions should set this parameter to at least -97dBm, ensuring a high probability of good Ec/No value after the HOand limiting the high increase of UTRAN incoming HO due to ping

pong handover.




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This parameter must be in accordance with 3G to 2G HOparameters.

In order to limit ping pong effect, a hysteresis of 5 dB is

recommended between fDDreportingThreshold and UTRAN hardHO 3G to 2G CPICH RSCP threshold.

fDDreportingThreshold2 Class 3 V17

Description: (applicable both to normal measurement reporting and EMR,applicable from MS release 5) CPICH Ec/N0 level measured onUTRAN cells, above which the mobile shall report UTRAN cells in theenhanced measurement report message

Value range: 0 to 63 (0 means “always reported”)


Default value: 0 (“always reported”)


Rec. value: 28



Eng. Rules: To ensure a good quality after the handover, a simultaneously not toorestrictive and good C/I value must be required.

Setting this parameter at 28 which corresponds to Ec/No = -10 dBseems to be a good compromise.

This parameter must be in accordance with 3G to 2G HOparameters.

In order to limit ping pong effect, a hysteresis of 2 dB isrecommended between fDDreportingThreshold2 and UTRANhard HO 3G to 2G Ec/No threshold.

Note: The Ec/No step is in half dB:

- “0” means always reported

- In range 1 to 49, “1” means “CPICH Ec/No ≥ -24 dB” and “49” means“CPICH Ec/No ≥ 0 dB”.

CPICH Ec/N0 level measured = - 24 + fDDreportingThreshold2 /2

- Values from 50 to 63 should not be used for Ec/No.

qsearchC Class 3 V17

Description: (applicable both to normal measurement reporting and EMR). Thisparameter is called Qsearch_C in the GSM specification. It gives theserving cell’s BCCH level below which the MS must listen toneighbours. If the serving BCCH frequency is not part of theBA(SACCH) list, the dedicated channel is not on the BCCH carrier,and qsearchC is not equal to 15, the MS shall ignore the qsearchCparameter value and always search for UTRAN cells. If qsearchC isequal to 15, the MS shall never search for UTRAN cells.

Value range: 0: “< -98 dBm”

1: “< -94 dBm”

2: “< -90 dBm”3: “< -86 dBm”




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4: “< -82 dBm”

5: “< -78 dBm”

6: “< -74 dBm”

7: “always”

8: “> -78 dBm”

9: “> -74 dBm”

10: “> -70 dBm”

11: “> -66 dBm”

12: “> -62 dBm”

13: “> -58 dBm”

14: “> -54 dBm”

15: “never”

QsearchC < -XX dBm: the HO towards the UMTS can be done only ifthe RxLev from the serving cell is below -XX dBm.

QsearchC > -XX dBm: the HO towards the UMTS can be done only ifthe RxLev from the serving cell is above -XX dBm.


Default value: 15 (“never”)


Rec. value: 7 (“always”)



Eng. Rules: Cases where a different value from “always” could be useful have notbeen identified. Therefore value “always” is recommended.

reportTypeMeasurement Class 3 V17

Description: type of measurement report to be reported on this cell : enhancedmeasurement report or legacy measurement report

Value range: 0 : Measurement report

1 : Enhanced Measurement Report

Object: bts


Rec. value: 1



Eng. Rules: To take advantage of EMR benefits it is recommended to activateEMR.

In case of HO 2G -3G activation either EMR or legacy measurementdoes not have any impact on the Handover 2G to 3G efficiency.




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servingBandReporting Class 3 V17

Description: (applicable to EMR only) This parameter sets the value of theSERVING_BAND_REPORTING field in Measurement Informationmessages.

It defines the number of cells from the GSM serving frequency bandthat shall be included in the list of strongest cells in the enhancedmeasurement report.

Value range: 0 : “no inband cell is favoured”

1: “1 strongest inband cell is favoured”

2: “2 strongest inband cells are favoured”

3: “3 strongest inband cells are favoured”

Object: bts

Default value: 3


Rec. value: 3Used in: Enhanced Measurement Reporting (EMR)

Eng. Rules: Depends on the network operator strategy.

servingBandReportingOffset Class 3 V17

Description: (applicable to EMR only) This parameter sets the value of theXXX_REPORTING_OFFSET field in Measurement Informationmessages, for the GSM band (XXX =900 or 1800 or 400 or 850 or1900).

If there is not enough space in the report for all valid cells, the cells

shall be reported that have the highest sum of the reported value(RXLEV) and the parameter servingBandReportingOffset(XXX_REPORTING_OFFSET) for the serving GSM band. Note thatthis parameter shall not affect the value itself of the reportedmeasurement.

Value range: 0, 1, ... 7, 0xFF : 0 dB, 6 dB, …, 42 dB, “not significant”


Default value: empty




Eng. Rules: This parameter should be tuned if EMR is used during an IMcampaign. If, during the Interference Matrix campaign in a dual bandnetwork, the reporting of serving band neighbours is deliberatelyfavoured by using the servingBandReportingOffset , then, as a side-effect, the traffic distribution may be modified. This undesirable side-effect may in turn modify the results of the IM measurements, whichtherefore may no longer reflect the real situation in the field once theIM has ceased. Therefore it is recommended to ensure that thechosen value of servingBandReportingOffset does not causeunacceptable changes in the traffic distribution.




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5.6. RADIO LINK FAILURE PARAMETERS

callReestablishment Class 3 V7

Description: Whether call re-establishment in a cell is allowed when the radio linkis broken off for propagation reasons

The information is broadcast to the mobiles at regular intervals on thecell BCCH.On receipt of a CHANNEL REQUIRED message with cause “call re-establishment”, the BSC attempts to allocate a TCH in one of the cellswhere call re-establishment is allowed. Then, if no TCH is availablethe BSC attempts to allocate a SDCCH.

Value range: [allowed / not allowed]

Object: bts

Default value: not allowed


Rec. value: allowed

Used in: Radio link failure process (run by the MS),

Call reestablishment procedure

Eng. Rules: Enabling or not this feature is a MSC capability issue

radioLinkTimeout Class 2 V7

Description: Maximum value of the counter (S) associated with the downlinkSACCH messages, beyond which the radio link is cut off. It is lower

than or equal to t3109.Mobiles comply with system operating conditions when the counter(S) is assigned a value lower than or equal to t3109.If the receiver is unable to decode a downlink SACCH message(BTS–to–MS direction), the counter is decreased by 1. If the messageis received, the counter is increased by 2. When the counter goesdown to zero, the radio link is declared “faulty”.

Value range: [4 to 64, by steps of 4] SACCH frames (1 unit = 480 ms on TCHs, 470ms on SDCCHs)

Object: bts

Default value: 20 SACCH


Rec. value: 2032 when AMR is activated




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Used in: Radio link failure process (run by the MS),

AMR - Adaptative Multi Rate FR/HR

Eng. Rules: radioLinkTimeOut < t3109.

If surrounding cells accept re-establishment (from GSM08 for DMS

MSC), overall process should not be too long. Small value: call might be dropped before a move to a more

favorable environment could occur.

High value: in case of permanent bad conditions, user’s anger and

taxation increase before actual call’s end or reestablishment.

Remark: The rlf1 attribute serves the same goal on the uplink, but the systemdoes not check that the values of the two attributes are consistent.

rlf1 Class 2 V8

Description: Value to compute the initial and maximum value of the (CT) counter

used in the BTS radio link control algorithmThe FP runs the following algorithm to monitor the uplink SACCHs(MS–to–BTS direction):The CT counter is reset to zero when the FP receives a CHANNEL ACTIVATION message.On each occurence of an uplink SACCH, the following occurs:

if the channel is decoded and CT = 0, then CT = 4 * rlf1 + 4

if the channel is decoded and CT ≠ 0, then CT = min (4 * rlf1 + 4,

CT+rlf2)

if the channel is not decoded, then CT = max (0, CT - rlf3)

When the CT counter goes down to zero, the radio link is broken and

the BTS sends a CONNECTION FAILURE INDICATION message tothe BSC.

Value range: [0 to 15]

Object: bts

Default value: 4


Rec. value: 4

7 when AMR is activated

Used in: Radio link failure process (run by the BTS),


Eng. Rules: The resulting CT value is the same as “radioLinkTimeOut” value.There is no reason to recommend to cut a communication morerapidly in the uplink or downlink direction. In a network with a lot oftraffic or with many zones of interference, a lower value (between 2and 4) of this parameter is recommended. Typically the value, in sucha case should be 2.

Notes: The radioLinkTimeOut attribute serves the same goal on the downlink,but the system does not check that the values of the two attributes areconsistent.




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rlf2 Class 2 V8

Description: Step value by which the (CT) counter is increased by the radio link

control algorithm when an uplink SACCH is decoded.Refer to the rlf1 entry.

Value range: [1 to 4] SACCH frames

Object: bts

Default value: 2


Rec. value: 2

Used in: Radio link failure process (run by the BTS)

Eng. Rules: The value should be higher than rlf3 value, in order to encourage thecontinuity of service. The higher the value, the longer an MS will keep

a bad quality communication in a disturbed zone. The choice of thisvalue must be made by the operator, in keeping with its service qualitylevel.

rlf3 Class 2 V8

Description: Step value by which the (CT) counter is decreased by the radio linkcontrol algorithm when an uplink SACCH is not decoded

Refer to the rlf1 entry.

Value range: [1 to 4] SACCH frames

Object: bts


Rec. value: 1

Used in: Radio link failure process (run by the BTS)

Eng. Rules: It is recommended to fix this value to 1. This allows the use of the rlf1value to set the maximal duration of consecutive non-reception ofSACCH frame.




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5.7. SIGNAL QUALITY AVERAGING PARAMETERS

missRxQualWt Class 3 V7

Description: Weight applied to missing Quality measurement

The missing measurement is replaced by the latest computedarithmetic average, or by the latest received raw measurement if noaverage value is available, weighed by this corrective factor whencalculating the average bit error rate in the radio link. The range ofpermitted values makes missing quality measurements not favored.

Value range: [100 to 200] %

Object: handOverControl

Default value: 110


Rec. value: 110Used in: Missing Downlink Measurements

Eng. Rules: The higher the value is, the higher the missing measurement will beweighted.

rxQualHreqave Class 3 V7

Description: Number of bit error rate measurements performed on a serving cell,used to compute arithmetic BER averages in handover and powercontrol algorithms

Value range: [1 to 10] number of measurement results

Object: handOverControlDefault value: 8


Rec. value: 4 in urban environment,

> 8 in rural environment

Used in: Measurement Processing

Eng. Rules: In order to minimize calculation of temporary averages it is better ifrunHandOver and runPwrControl are multiples or sub multiples ofrxQualHreqAve. Length of weighed average window should bereduced when the cell is small or environment requires quickreactivity. Studies have shown that a reduction of the window size

value (from 8 to 4 for instance) does not increase the number ofhandovers on a network and does not change handover causes.

However, it has a positive impact, because it leads to a greaterreactivity.Then, the weighted average window size (rxQualHreqAve *rxQualHreqt) has to be correlated to the hoMargin value to keep a lowping-pong probability.The larger the window size, the lower the hoMargin should be.




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rxQualHreqt Class 3 V7

Description: Number of arithmetic averages taken into account to compute the

weighted average bit error rate in handover and power controlalgorithms. Each is calculated from rxQualHreqave bit error rate(BER) measurements on a radio link.



Default value: 1


Rec. value: 1


Eng. Rules: The quality and signal strength weighted average window shouldencompass the same period. For the sake of simplicity, the default

value disables weighting. The weighed average window size(rxQualHeqAve * rxQualHreqt) must be correlated to the hoMarginvalue to keep a low ping-pong probability.

The larger the window size, the lower the hoMargin should be.

rxQualWtsList Class 3 V7

Description: List of up to sixteen weights used to compute the average bit errorrate on a radio link

The L1M function calculates rxQualHreqave arithmetic averages fromraw measurements, and balances rxQualHreqt averages among those

with the weights defined in rxQualWtsList.Each arithmetic average is partnered with one weight in the list.Weight/average associations are set in the order in which the weightsare recorded. The latest computed arithmetic average is alwayspartnered with the first weight in the list.Super–average = [∑ (averagei x weighti)] / 100, i = 1 to rxQualHreqt



Default value: 100


Rec. value: 100

Used in: Measurement Processing Eng. Rules: Values add up to 100.

If there are several values, the biggest weights must be used for morerecent reports.In rural environment, rxLev and rxQual weighed average window willnot refer to the same time window.




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5.8. SIGNAL STRENGTH AVERAGING PARAMETERS

missRxLevWt Class 3 V7

Description: Weight applied in case of missing signal strength measurementreport

The missing measurement is replaced by the latest computedarithmetic average, or by the latest received raw measurement if noaverage value is available, weighed by this corrective factor whencalculating the average signal strength in the cell.Selecting the greatest value makes missing strength measurementsnot favored.



Default value: 90


Rec. value: 90


Eng. Rules:

rxLevHreqave Class 3 V7

Description: Number of signal strength measurements performed on a serving cell,used to compute arithmetic strength averages in handover and powercontrol algorithms

Value range: [1 to 10] number of measurement resultsObject: handOverControl

Default value: 8


Rec. value: 6 for small cells (Dintersite < 800m)

between 8 and 10 for large cells (Dintersite > 1600m)


Eng. Rules: In order to minimize calculation of temporary averages it is better ifrunHandOver and runPwrControl are multiples or sub multiples ofrxLevHreqAve. In an urban environment, the window size should beminimized and the hoMargin value should be high. However, choosing

too small a value leads to averaging meaningless measures in case ofDTX activation uplink or downlink. Then, in an urban environment,according to building density, antenna height and global environment,the window size can fluctuate between 6 and 8. The minimum value,6, may be preferred, because it ensures a good reactivity without badinfluence if the parameter hoMargin is well chosen.




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rxLevHreqaveBeg Class3 V11

Description: Number of measurement reports used in short averaging algorithm on

current cell for signal strength arithmetic averageRefer to the rxLevHreqave entry in the Dictionary.



Default value: 2


Rec. value: 2

Used in: Early HandOver Decision

Automatic handover adaptation Fast power control at TCH assignment

Eng. Rules: rxLevHreqaveBeg < rxLevHreqaveThis parameter has to be coupled with hoMarginBeg andrxLevNCellHreqaveBeg.

Remark: This parameter is only available for DCU4 or DRX transceiverarchitecture.

rxLevHreqt Class 3 V7

Description: Number of arithmetic averages taken into account to compute theweighted average signal strength in handover and power controlalgorithms. Each is calculated from rxLevHreqave signal strengthmeasurements on a serving cell.



Default value: 1


Rec. value: 1


Eng. Rules: In a urban environment, the window size should be minimized and thehoMargin value should be high.

For the sake of simplicity, weighted averaging is disabled by defaultvalue.

CAUTION! The weighted average is not used for the PBGT. The weighedaverage window size (rxLevHreqAve * rxLevHreqt) has to becorrelated to the hoMargin value to keep a low ping-pong probability.The larger the window size, the lower the hoMargin should be.




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rxLevWtsList Class 3 V7

Description: Values of weights to be used for signal strength weighed average

The L1M function first calculates rxLevHreqave arithmetic averagesfrom raw measurements, and balances rxLevHreqt averages amongthose with the weights defined in rxLevWtsList.Each arithmetic average is partnered with one weight in the list.Weight/average associations are set in the order which the weightsare recorded. The latest computed arithmetic average is alwayspartnered with the first weight in the list.Super–average = [ ∑ (averagei x weighti)] / 100, i = 1 to rxLevHreqt



Default value: 100

Type: DP, OptimizationRec. value: 100


Eng. Rules: Arithmetic law to be preferred, biggest weight for most recent reports




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5.9. NEIGHBOR CELL AVERAGING PARAMETERS

cellDeletionCount Class 3 V7

Description: The cellDeletionCount is to be compared to the number ofconsecutive Measurement Results messages not containinginformation on one of the neighbour cells that would result in the cellbeing no longer eligible.

(TF 1089-2), from a number ≥ cellDeletionCount the cell will be noneligible, but the information of that neighbour cell will only bediscarded when the number of consecutive Measurement Results withno information on the cell will reach 10 (i.e. 5 sec).


Object: bts

Default value: 5 in rural environment, 2 in microcell environment

Type: DP, Design

Rec. value: 5 in rural,

2 in urban environment


Handovers screening

Eng. Rules: As there is no weighting factors on neighboring cells, low values ofcellDeletionCount are advised and so the rule cellDelectionCount <rxNcellHrequave. A mobile is required to keep synchronizationinformation at least 10 seconds after a cell was removed from the bestcells list. This synchronisation becomes quickly obsolete in the case offast moving mobiles.

CAUTION! This mechanism applies only for Power budget handover.

Remark: Further informations are provided in chapter Best Neighbor CellsStability




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rxNCellHreqave Class 3 V7

Description: Number of measurement results used in the PBGT algorithm to

compute the average neighboring signal strengthNo weighed average is computed for this category of measurement

Value range: [1 to 10] number of measurement results


Default value: 8


Rec. value: 6 for small cells (Dintersite < 800m)

between 8 and 10 for large cells (Dintersite > 1600m)



Automatic handover adaptation Eng. Rules: In the PBGT formula, the RXLEV_DL is the last arithmetic signal

strength on the current cell. In order to use the same time base, weshould have rxNcellHreqAve = rxLevHreqAve.

rxLevNCellHreqaveBeg Class 3 V11

Description: Number of measurement results used in short averaging algorithm tocompute the average neighboring signal strength



Default value: 2


Rec. value: 2

Used in: Early HandOver Decision

Eng. Rules: rxLevNCellHreqaveBeg < rxLevNCellHreqave

This parameter has to be coupled with hoMarginBeg andrxLevHreqaveBeg.





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5.10. DISTANCE AVERAGING PARAMETERS

distHreqt Class 3 V7

Description: Number of distance measurements, used to compute the weightedaverage MS–to–BTS distance in handover algorithms



Default value: 4


Rec. value: 4


Eng. Rules: For distance handover and Call Clearing, a weighted average of theMS-BS distance is computed from timing-advance results.

distWtsList Class 3 V7

Description: List of no more than sixteen weights, used to compute the averageMS–to–BTS distance from distHreqt measurements

The L1M function balances distHreqt raw measurements with theweights defined in the distWtsList list. Each measurement is partneredwith one weight in the list. Weight/measurement associations are setin the order which the weights are recorded. The latest receivedmeasurement is always partnered with the first weight in the list.Super–average = [∑ (measurementi x weighti)] / 100, i = 1 to distHreqt

Value range: [0 to 100] %Object: handOverControl

Default value: 40 30 20 10


Rec. value: 40 30 20 10


Eng. Rules: A supply weights to distHreqt values, highest value for latestmeasurements. Choosing an arithmetic law enables to enhance latestvalues while not putting too much weight upon the period of timewhich might not be representative of the current trend.




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missDistWt Class 3 V7

Description: Weight applied to missing Distance measurement.

The missing measurement is replaced by the latest received rawmeasurement weighed by this corrective factor when calculating theaverage MS–BTS distance.The range of permitted values makes missing distance measurementsnot favored.



Default value: 110


Rec. value: TBD


Eng. Rules: The higher the value is, the higher the missing measurement will beweighted.




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5.11. HANDOVER (GLOBAL) PARAMETERS

bts time between HO configuration Class 3 V9

Description: Whether the hoPingpongTimeRejection timer can be used at bts levelwhen processing handovers

Value range: [0 / 1]

“0”:The timer is disabled.

“1”:The timer is used.

Object: bts

Default value: 0


Rec. value: 1

Used in: Minimum time between Handover


Eng. Rules: New semantic in order to restore the minimum time between HOfeature (TF218, V9):

timeBetweenHOconfiguration = used

bts time between HO configuration = 1

ho Pingpong combinaison = (all, allPBGT)

ho Pingpong Time Rejection > 0

forced handover algo Class 3 V9

Description: Minimum signal strength level received by the mobiles to be grantedaccess to a neighbor cell in case of forced handover

Value range: [less than -110, -110 to -109, ..., -49 to -48, more than -48] dBm

Object: adjacentCellHandover

Default value: less than -110


Rec. value: = rxLevMinCell -1

Used in: Forced Handover

Eng. Rules: The neighbour cell eligibility criterion for forced handover comparesthe Rxlev received by the mobile from the neighbour cells with thevalue of "forced handover algo". If the Rxlev is greater than "forced

handover algo", then the forced handover is triggered. Therefore :

the higher the value of "forced handover algo" parameter, theless efficient the forced handover feature, because fewer mobileswill comply with the eligibility criterion. The mobiles who arelocated too far away from the strongest neighbour cell will bekept by the network on the current cell. So, it will take longer toempty the cell because the operator has to wait for all mobiles tomove around and get closer to a neighbour cell. Note that it doesnot make sense to set "forced handover algo" to a higher valuethan "rxLevMinCell", although nothing prevents from doing so.

the smaller the value of "forced handover algo" parameter, thefaster mobiles will be forced out of the current cell. On the

downside, if "forced handover algo" is significantly lower than"rxlevMinCell", quality of service for the mobile on the destinationcell will be poorer with a risk, ultimately, of call drop.




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Therefore a compromise should be found, and BPUG recommendsthat forced handover algo = RxlevMinCell - 1dB. This is only arecommendation. A different value may be chosen by the customer.

handOver from signalling channel Class 3 V7

Description: Authorization to perform intercell handovers on signalling channels(SDCCH or TCH in signalling mode)

Value range: [enabled / disabled]


Default value: disabled

Type: DP, Design

Rec. value: disabled

Used in: Direct TCH Allocation and Handover Algorithms

Eng. Rules: It is recommended to enable this feature when queuing is activated.

hoMargin Class 3 V7

Description: Margin to use for PBGT handovers to avoid subsequent handover, inPBGT formula

Value range: [-63 to 63] dB

Object: adjacentCellHandOver

Default value: 4


Rec. value: between 4 and 6 for small cells

(4 in an 1X1 pattern, 5 or 6 otherwise),5 for large cells.

Used in: Handovers

Power budget formula Handover for traffic reasons Define eligible neighbor cells for intercell handover (except directedretry) Automatic handover adaptation

Eng. Rules: As a general rule, this parameter enables to harden access to a newcell in order to avoid a subsequent return to the current cell (providedrxLevMinCell is set to its minimal value and does not already take intoaccount ping-pong handover protection).

The value of this hoMargin must be correlated to the window sizevalue to keep a low ping-pong probability. In case of ping-pong,handover hoMargin value must be incremented, and the window sizevalue must be decremented.For a dual Band Network where one frequency band is privileged, it isadvised to increase this value in neighbouring objects with afrequency belonging to the low priority frequency band. Thus, theseneighbours will be underprivileged.




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hoMarginBeg Class 3 V11

Description: Margin that is added to hoMargin, concentAlgoExtRxLev,

amrDirectAllocRxLevUL, amrDirectAllocRxLevDL,amrDirectAllocIntRxLevUL, amrDirectAllocRxLevDL,bizonePowerOffset, until rxLevHreqave for short averaging algorithmin order to compensate the lack of reliable measurements

This parameter is coupled with hoMargin, concentAlgoExtRxLev,amrDirectAllocRxLevUL, amrDirectAllocRxLevDL,amrDirectAllocIntRxLevUL, amrDirectAllocRxLevDL,bizonePowerOffset and rxLevHreqaveBeg.

Value range: [0 to 63] dB

Object: bts

Default value: 4 dB

Type: DP, OptimizationRec. value: 4 dB

2 dB with Automatic Handover Adaptation

Used in: Handovers

Early HandOver Decision Automatic handover adaptation Direct TCH Allocation

Eng. Rules:


hoMarginDist Class 3 V8

Description: Margin to be used for Distance Handovers



Default value: - 24 dB


Rec. value: - 2 dB

Depends on the environment and on the value of themsRangeMax Threshold.

Used in: Handover condition for leaving a cell on distance Define eligible neighbor cells for intercell handover (except directedretry)

Eng. Rules: Because the priority of the handover on Distance cause is lower thanthe Quality and Strength causes, it is performed while the quality andthe signal strength on the current cell are still acceptable. Setting anegative value decreases the interference.

CAUTION! PBGT hoMargin in the target cell should be set in order to avoid aping-pong handover. For a dual Band Network where one frequencyband is privileged, it is advised to increase this value in neighbouringobjects with a frequency belonging to the low priority frequency band.Thus, these neighbours will be underprivileged.




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CAUTION! PBGT hoMargin in target cell should be set in order to avoid a ping-pong handover. This parameter, defined per neighbor, is used toselect and sort neighbors. For a dual Band Network where onefrequency band is privileged, it is advised to increase this value inneighbouring objects with a frequency belonging to the low priority

frequency band. Thus, these neighbours will be underprivileged.

hoMarginTrafficOffset Class 3 V12

Description: Minimum signal strength margin with the serving cell that allows toselect the best neighbor cell when a handover is triggered for overloadreasons



Default value: 0 dB


Rec. value: 6 dB (if overlapping exists)

Used in: Handovers


Eng. Rules: Since the HO for traffic reasons uses the PBGT HO procedure, theparameter powerBudgetInterCell shall be “enabled”.

It is advised to combine the HO for traffic reason with the feature HOdecision according to priority and Load.This parameter shall be set at a value which guarantees that celloverlapping exists with (hoMargin -hoMarginTrafficOffset).See Paragraph 2.5k9 for more details.When set to “0”, handovers for traffic reasons are not allowed in the

adjacent cell (the PBGT HO is done before because it has a higherpriority than the HO for traffic).

CAUTION Only applicable to BTSs equipped with non mixed DCU4, or DRXboards

hoPingpongCombination Class3 V12

Description: List of couples of causes (HOInitialCause and HONonEssentialCause)indicating the causes of ping-pong handovers in the overlapping areas

The following causes are defined with regard to the neighboring cell:

HOInitialCause indicates the essential handover cause which leads

to enter the neighbor cell (cause of incoming handover). HONonEssentialCause indicates the non-essential handover

cause which leads to leave the cell (cause of outgoing handover).

This parameter defines the combination for which theHOPingpongTimeRejection attribute is used.

Value range: [rxQual, rxLev, distance, powerBudget, capture, directedRetry, OaM,traffic, all, allCapture, allPowerBudget, AMRquality]


Default value:


Rec. value: (all, PBGT)Used in: General protection against HO ping-pong




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Eng. Rules: This parameter shall be known by the new BSC (whatever the type ofHO is intra or inter BSC) ; so, it must be defined at the “entering cell”(relatively to the first HO of the combination) level, for theneighbouring cell (adjacentCellHandover object) corresponding to the“left cell” (still relatively to the first HO of the combination).

Example: if you perform a handover from cell A to cell B for qualityreason and you want to protect against pingpong HO for PBGTreason (from B to A), you have to declare (rxQual, PBGT) as one ofthe forbidden handover combinations at cell B level (for theneighbouring cell A).

Note: The hoPingpongCombination list can hold up to 4 couples of causes.

CAUTION! No protection against intracell or interzone pingpongHO

No protection against pingpong HO between more than 2 cells exceptfor allcapture / all PBGT causes.Directed retry can only be an initial cause.timeBetweenHOConfiguration and bts Time Between HOconfiguration shall be set accordingly in order for the feature to be

activated.

hoPingpongTimeRejection Class 3 V12

Description: Time before a new handover attempt can be triggered

Refer to bsc object timeBetweenHOConfiguration and bts object btstime between HO configuration attributes in this Dictionary ofParameters for this timer activation.Refer to adjacentCellHandOver object HOPingpongCombination attribute in this Dictionary of Parameters for the combinations forwhich this timer applies.To avoid ping-pong handovers this new timer is started after asuccessful handover. Up to the expiration of this timer, the receipt ofHANDOVER INDICATION message is ignored.

Value range: [0 to 60] s


Default value: 30 s


Rec. value: between 8 and 30 s

Used in: General protection against HO ping-pong

Eng. Rules: The value of “HOPingpongTimeRejection” may be between 8 and 30to have a real impact. The following rule can be applied:

HOPingpongTimeRejection = 50% TCH effective occupancy averagein a cell.

If the rescue handovers are disabled in the network a too high valuecan result in dropped calls.The value depends on the speed of the mobile, the size of the cell andthe type of cell (micro-micro etc).For an area where there are ping-pong handovers on “Quality” cause(the first HO occurs on “Quality” reason, the second one on PBGT),the value corresponds to the distance between the interference pointand the limit of the cell.Care must be taken for small cells with high speed mobiles.See also chapter Minimum Time Between Handover




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hoSecondBestCellConfiguration Class 3 V9

Description: Number of neighbor cells in which the BSC immediately attempts to

perform a new handover when the previous handover attempt failedwith return to the old channel

Giving the attribute a value greater than 2 allows the BSC to renewthe handover request without waiting for a new set of radiomeasurements (the first attempt is included in this count). The samelist of neighbor eligible cells is used to process the request (no new listis provided by the BTS).


Object: bsc

Default value: 3

Type: DP, Design

Rec. value: 3Used in: Handover to 2nd best candidate when return to old channel

Eng. Rules: The value 1 means no new attempt after a handover failure, 2 meansone new attempt and 3 corresponds to another new attempt if the firstnew attempt has failed. The recommended value optimizes thehandover completion rate.

Comment about the process: when all handover attempts have failed,the mobile returns on the previous channel. The measurement historyis then complety lost, and the BTS will wait until the next (HReqAve xHReqt) period to relaunch a handover request.See also chapter Directed Retry Handover Benefit

hoTraffic Class 3 V12

Description: Whether handovers for traffic reasons at bts level are allowed.

Value range: [disabled / enabled]

Object: bts

Default value: enabled


Rec. value: enabled

Used in: Handover for traffic reasons

Eng. Rules: “enabled” will be effective only if it is also “enabled” for the bsc object.

In order to activate the feature “handover decision according toadjacent cell priority and load” (TF716), either hoTraffic shall be“enabled” or btsMSAccessClassBarringFunction shall be “enabled”(with also bscMSAccessClassBarringFunction).See parameter hoMarginTrafficOffset

hoTraffic Class 3 V12

Description: Whether handovers for traffic reasons at bsc level are allowed.


Object: bsc






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Rec. value: enabled (only if “hot spot”cells linked to the BSC)

Used in: Handover for traffic reasons

Eng. Rules: See parameter hoMarginTrafficOffset

incomingHandOver Class 3 V7

Description: Whether incoming handovers are allowed in a cell.




Type: DP

Rec. value: enabled

Used in:

Eng. Rules:

msTxPwrMax Class 3 V7

Description: Maximum MS transmission power in a serving cell. It is equal tomsTxPwrMaxCCH in a GSM 900 network.

Value range: [5 to 43, by steps of 2] dBm (GSM 900, GSM850, GSM-R, GSM850-GSM1900 and GSM 900 - GSM 1800 networks)

[0 to 36, by steps of 2] dBm (GSM 1800, and GSM 1800 - GSM 900networks)[0 to 33] dBm (GSM 1900 network)[0 to 33] dBm (E-GSM network and 1900-850 network)[0 to 33] dBm (GSM850 network)

Object: bts

Default value: Typical value of 33 dBm for GSM 900 handhelds and 30 dBm forGSM 1800 and 1900 handhelds


Rec. value: 33 dBm for GSM 900 in urban environment

39 dBm for GSM 900 in rural environment handhelds

30 dBm for GSM 1800 and 1900 handhelds

33 dBm for GSM 850s

Used in: Accuracy related to measurements

General formulas

Forced Handover One shot power control Power control on mobile side

Eng. Rules: We must have msTxPwrMax = msTxPwrMaxCCH for GSM 900Networks and msTxPwrMaxCCH ≤ msTxPwrMax for GSM 1800 and1900 Networks (check done at OMC-R). This parameter is adapted tomobile classes taken into account in Network Design.




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msTxPwrMaxCell Class 3 V7

Description: Maximum MS transmission power in a neighbor cell. It is equal to

msTxPwrMaxCCH when the cell is declared as a serving cell on thenetwork (the value must be checked by users).

Value range: [5 to 43, by steps of 2] dBm (GSM 900, GSM850, GSM-R and GSM900 - GSM 1800 networks)

[0 to 36, by steps of 2] dBm (GSM 1800 networkand GSM 1800 - GSM 900)[0 to 33] dBm (GSM 1900 network)[0 to 33] dBm (E-GSM network)[0 to 33] dBm (GSM 1900-850 network)


Default value: Typical value of 33 dBm for GSM 900/850 handhelds and 30 dBm forGSM 1800 and 1900 handhelds


Rec. value: msTxPwrMaxCell = msTxPwrMaxCCCH of the current cell

Used in: General formulas

Handovers screening Directed Retry Handover: BTS (or distant) mode Forced Handover Define eligible neighbor cells for intercell handover (except directedretry) One shot power control Power control on mobile side

See Paragraph 2.5.1 and Paragraph 2.7.

Eng. Rules: If this value is higher than the actual MS classmark, then MS will applyits own capability.

Remark: If the cell is used as a neighbor cell of another serving cell in thenetwork, msTxPwrMaxCell should be identical to themsTxPwrMaxCCH power defined for the correspondingadjacentCellHandOver object (the values must be checked by users).




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offsetLoad Class 3 V12

Description: Load offset applied by the bsc in the cell selection process of the

Handover algorithm.Value range: [0 to 63] dB


Default value: 0 dB


Rec. value: 3 dB

offsetLoad ≥ hoMarginTrafficOffset (Handovers for traffic reasonfeature activated)

Used in: Handover decision according to adjacent cell priorities and load Eng.Rules: When set to “0”, no offset is effective.

This parameter is set to “0” for the cells that do not belong to the

related bsc object.This parameter allows to put a disadvantage to overloaded eligiblecells for HO (for cells with the same offsetPriority).In order to take into account this parameter, the overload detectionmust be activated ; so either hoTraffic shall be “enabled” (bsc and btsobjects) or btsMSAccessClassBarringFunction shall be “enabled”(with also bscMSAccessClassBarringFunction). A bad offset load parameter tuning can induce a risk of ping-pong HOor longer handover procedures; so, it is advised to set the “Generalprotection against HO ping-pong” feature withHOPingpongCombination including (traffic, all PBGT).See also chapter Handover for Traffic Reasons Activation Guideline.

offsetPriority Class 3 V12

Description: Priority offset applied by the bsc to the cell selection process in theHandover algorithm



Default value: 1


Rec. value: 1

Used in: Handover decision according to adjacent cell priorities and load

Eng. Rules: “1” is the highest priority.

This parameter allows to classify eligible cells according to its value;so, it is used to optimize the traffic distribution between layers.See also chapter DualBand Networks.




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powerBudgetInterCell Class 3 V7

Description: Authorization to perform intercell handovers for power budget





Rec. value: enabled

Used in: Handovers screening

Power budget formula Handover for traffic reasons

Eng. Rules: Handover on PBGT should be enabled, because for an optimizednetwork it ensures the best quality of service.

runHandOver Class 3 V7

Description: Number of Measurement Results messages that must be receivedbefore the handover algorithm in a cell is triggered

Value range: [1 to 31] SACCH frames (1 unit = 480 ms on TCHs, 470 ms onSDCCHs)

Object: bts

Default value: 1

Type: DP, System

Rec. value: 1

Used in: Handovers

Microcellular Algo type A Protection against RunHandover=1

Eng. Rules: Should be run as often as possible, main impact is upon BSS load.

Therefore, runHandOver may be set to 1 in some environments wherethe reactivity is crucial (microcell, high-speed environment). it isrecommended to set this parameter to 1. However, this parametersetting must be done in accordance with the value of handoverthresholds, margins and timers.See also chapter Impact of the Averaging on the Handovers andchapter Street Corner Environment




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rxLevMinCell Class 3 V7

Description: Minimum signal strength level received by MS for being granted

access to a neighbor cellValue range: [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm


Default value: - 95 to -94 dBm (GSM 900 & 850), - 93 to - 92 (GSM 1800 & 1900)


Rec. value: - 95 to - 94 dBm (GSM 900 & 850)

- 93 to - 92 dBm (GSM 1800& 1900) in urban environment

RxLevMinCell = lRxLevDLH if HOmargin ≥ 0 in rural environment


Handovers screening

Define eligible neighbor cells for intercell handover (except directedretry)

Eng. Rules: A method to estimate this value is to use MS sensitivity (-104 dBm inGSM 900 for handheld, and -102 dBm in GSM 1800/1900 forhandheld, otherwise -104 dBm) and applying a margin to it. However,if most of communications are handled in an indoor environment, oroverlap between cell coverage is not sufficient, these recommendedvalues can be decreased.

For a dual Band Network where one frequency band is privileged, it isadvised to set this parameter to a lower value in neighbour cellsbelonging to the priority frequency band. Thus, this band will bepreferred. However, it may be greater than the value rxLevAccessMin.Thus the recommended value is -99 to -98 dBm (GSM900) or -97 to -96 dBm (GSM1800) for neighbour cells belonging to the priorityfrequency band.Studies have shown that the subjective quality depends on the wayerroneous bits are spread into each frame. Experiments have shownthat with frequency hopping in TU3 (Typical urban at 3 Km/h) up toRxqual = 5 the subjective quality seems to be good, on the other handwithout frequency hopping Rxqual = 4 seems to be the maximumvalue for which subjective quality is good.The table below gives examples of the margins that could be takeninto account for an infinite C/I and for different mobile speeds.

t 50 km/h u 50 km/h - t 80 km/h u 80 km/h

margin with FH 2 dB 2 dB 2 dB

margin without FH 5 dB 4 dB - 2 dB 2 dB

And that other table below shows the different margins that could betaken into account in a slow mobile area depending of the C/I.

C/I = 35 C/I = 20 C/I = 15

margin with FH 2 dB 3 dB 4 dB

margin without FH 5 dB 6 dB 10 dB

See also chapter Directed Retry Handover Benefit and chapter

DualBand Networks.




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synchronized Class 3 V7

Description: Whether the neighbor cell and the associated serving cell aresynchronous, that is attached to the same BTS

Value range: [not synchronized cells / synchronized cells / pre sync HO with timing

advance / pre sync HO, default timing advance]

“not synchronized cells”: the neighbor cell and the serving cell are

not attached to the same BTS.

“synchronized cells”: the neighbor cell and the serving cell are

attached to the same BTS

“pre sync HO with timing advance”: the handover procedure

between the neighbor cell and the serving cell is pre–synchronized

with the real Time Advance.

“pre sync HO, default timing advance”: a pre–defined timing

advance is used in the pre–synchronized handover procedure

between the serving cell and the neighbor cell. Refer topreSynchroTimingAdvance parameter.


Default value: not synchronized cells



Used in: Pre-synchronized HO

Handover Algorithms on the Mobile Side

Eng. Rules: It is recommended to use pre-synchronized HO in microcellularenvironment because in small cells the timing advance whenhandovers are triggered is generally a low value (less than 3).

It is also interesting to use this feature for determined path such asrailways, highways, and tunnels where handovers between two cellshappen always at the same place.See also chapter Synchronized HO versus Not Synchronized HO

timeBetweenHOConfiguration Class 3 V9

Description: Whether the HOPingpongTimeRejection timer can be used in a BSSwhen processing handovers. Refer to bts object bts time between HOconfiguration and adjacentCellHandOver objectHOPingpongTimeRejection attributes in this Dictionary of Parameters.

Value range: [used / not used]

Object: bsc

Default value: used

Type: DP, Design

Rec. value: used

Used in: Power Budget Handover


Eng. Rules: see Engineering Rules for the parameter bts time Between HOConfiguration.

See also chapter Minimum Time Between Handover and chapterDirected Retry Handover Benefit.




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5.12. INTRACELL HANDOVER PARAMETERS

intraCell Class 3 V7

Description: Whether intra–bts handovers on TCH are allowed in a cell forinterference reasons or Cell Tiering reasons

Value range: [cellTieringHandover / intraCellHandover / handoverNotAllowed]

cellTieringHandover: the intraBTS handovers are allowed for

CellTiering reason

intraCellHandover: the intraBTS handovers are allowed for

interference reason

handoverNotAllowed: the intra bts handovers are not allowed


Default value: handoverNotAllowed

Type: DP, Design

Rec. value: cellTieringHandover

Used in: Intracell Handover decision for signal quality

Eng. Rules: For mono-TRX cell, do not enable intracell handover(handoverNotAllowed).

As the MS power is not checked before performing an intracellhandover, it is not advised to enable this feature as intraCellHandover.It would lead to a high ratio of intracell handover.To enable “tiering”, the cell tiering conditions shall be fulfilled and thecell tiering advantages shall be estimated as well (see chapter Automatic cell tiering and hoMarginTiering parameter).

intraCellSDCCH Class 3 V8

Description: Whether intraBTS handovers on SDCCH are authorized in a cell forinterference reasons







Eng. Rules: None except system ability.

Note that, some mobiles have been reported to drop the call whenthat feature is performed.




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rxLevDLIH Class 3 V7

Description: Maximum interference level in BTS–to–MS direction, beyond which an

intraCell handover may be triggeredValue range: [less than -110, -110 to -109,..., -49 to -48, more than -48] dBm


Default value: -85 to -84 dBm


Rec. value: -85 to -84 dBm


Eng. Rules:

CAUTION! Path balance must be looked for this threshold parameter setting.

rxLevULIH Class 3 V7

Description: Maximum interference level in MS–to–BTS direction, beyond which anintra cell handover may be triggered

Value range: [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm.






Eng. Rules:CAUTION! Path balance must be looked for this threshold parameter setting.




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rxQualDLIH Class 3 V12

Description: Bit error rate threshold in BTS-to-MS direction for intracell handover,

above which a handover may be triggered.Value range: [less than 0.2, 0.2 to 0.4, 0.4 to 0.8, ... , 6.4 to 12.8, more than 12.8] %


Default value: 1.6 to 3.2 %


Rec. value: rxQualDLIH ≤ lRxQualDLH


Eng. Rules: Intracell HO for signal quality uses a different threshold than theintercell one and intracell HO can only use either hopping channelshaving low interference or non hopping channels having lowinterference. This should improve the voice quality and the

performance.The possible drawback could be to increase queuing at BSC level fornetworks experiencing interferences.To favor intracell HO for quality (compared to intercell HO for quality),the following rule shall be satisfied: rxQualDLIH < lRxQualDLH.The intracell HO has a lower priority than the intercell HO for quality.

rxQualULIH Class 3 V12

Description: Bit error rate threshold in MS-to-BTS direction for intracell handover,above which a handover may be triggered.

Value range: [less than 0.2, 0.2 to 0.4, 0.4 to 0.8, ... , 6.4 to 12.8, more than 12.8] %Object: handOverControl



Rec. value: rxQualULIH ≤ lRxQualULH


Eng. Rules: Intracell HO for signal quality uses a differentthreshold than theintercell one and intracell HO can only use either hopping channelshaving low interference or non hopping channels having lowinterference. This should improve the voice quality and theperformance.

The possible drawback could be to increase queuing at BSC level fornetworks experiencing interferences.To favor intracell HO for quality (compared to intercell HO for quality),the following rule shall be satisfied: rxQualULIH < lRxQualULH.The intracell HO has a lower priority than the intercell HO for quality.




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5.13. INTERCELL HANDOVER THRESHOLD PARAMETERS

lRxLevDLH Class 3 V7

Description: Signal strength threshold in BTS–to–MS direction, below which ahandover may be triggered



Default value: -101 to -100 dBm (GSM 900) / -99 to -98 dBm (GSM1800/1900)


Rec. value: -95 to -94 dBm in urban environment (900 MHz or 850 MHz)

-101 to -100 dBm in rural environment (900 MHz or 850 MHz)

Used in: Handover condition for leaving a cell on rxlev

Define eligible neighbor cells for intercell handover (except directed

retry)

Eng. Rules: This threshold must be set from the MS sensitivity. A margin must betaken to consider shadowing, fast fading and MS measurementaccuracy. At least, a 3 dB margin can be taken into account in a ruralenvironment and a 10 dB margin in an urban environment.

CAUTION! where the cell is declared as a neighbor, we should have: lRxLevDLH< rxlevMinCell, and path balance must be considered for thisthreshold parameter setting.

See also chapter lRxlevDLH and lRxlevULH Definition.

lRxLevULH Class 3 V7Description: Signal strength threshold in MS–to–BTS direction, below which a

handover may be triggered



Default value: -101 to -100 dBm (GSM 900) / -99 to -98 dBm (GSM 1800/1900)


Rec. value: -95 to -94 dBm in urban environment (900 MHz or 850 MHz)

-101 to -100 dBm in rural environment (900 MHz or 850 MHz)

Used in: Handover condition for leaving a cell on rxlev

Eng. Rules: The recommended values given above correspond to the worst caseBTS (e-cell). An e-cell has -104 dBm Rx sensitivity in all frequencybands and diversity is not applicable, thus leading to "-95 to -94" forurban environments and "-101 to -100" for rural environments whenapplying a 3dB margin in a rural environment and a 10 dB margin inan urban environment. In fact, these thresholds depend on BTSsensitivity. Values should be increased if one of the following points isverified:

the thresholds on quality are permissive

run-handover 3 scarce

mobile speed is high

initial tuning causes frequent level strength handover failure rate

At least, a 3 dB margin can be taken into account in a ruralenvironment and a 10 dB margin in an urban environment.




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CAUTION! where the cell is declared as a neighbor, we should have: lRxLevULH< rxLevMinCell, and path balance must be considered for thisthreshold parameter setting.

See also chapter lRxlevDLH and lRxlevULH Definition.

lRxQualDLH Class 3 V7

Description: Bit error rate threshold in BTS–to–MS direction, above which an intercell handover may be triggered

Value range: [less than 0.2, 0.2 to 0.4, 0.4 to 0.8, ... , 6.4 to 12.8, more than 12.8] %




Rec. value: 1.6 to 3.2 % (4 in rxqual GSM unit) without frequency hopping.

See Engineering Rules in case of frequency hopping.

Used in: Handover condition for leaving a cell on rxqual

Eng. Rules: According to some experiments and studies, 4 in GSM unit is theupper limit for TU3 no hopping, while 5 in GSM unit for TU3 hopping.Suggested values become 4 in GSM unit (no frequency hopping orMS speed > 80km/h) and 5 in GSM unit (frequency hopping and lowurban speed). High BER rate for threshold is dangerous (risk ofhandover failure). On the contrary, if a tight rxqual threshold is linkedwith a short averaging period, the risk is that a single bad qualityreport will affect the whole result (ie: if 8 samples without weightingand a threshold of 2 in GSM unit: if 7 of these samples are 2 in GSMunit and 1 of them is 5 in GSM unit, handover decision will be takenon a wrong basis). Experience shows whatever the MS speed, rxQual

= 6 does not provide a comfortable voice quality.The average in the above is equal to:(7 * 0.57 + 4.53) B 8 = 1.065 greater than 0.57 (2 in GSM unit).In case of using synthesized frequency hopping, this threshold has tobe increased in order to limit the increase of the number of handoveron quality criteria.In a 1X1 pattern, it is advised to set this value to 5 or 6 (3.2 to 6.4 %or 6.4 to 12.8 %).In case of a 1X3 pattern, the recommended value is 4 or 5 (1.6 to 3.2% or 3.2 to 6.4 %).DTX is often used with Frequency Hopping. There are lessmeasurement reports with DTX, and thus the RxQual_average maybe less reliable. But no degradation was observed when using both

features therefore there is no need to disable handovers on qualitycriteria in this case.

lRxQualULH Class 3 V7

Description: Bit error rate threshold in MS–to–BTS direction, above which an intercell handover may be triggered








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5.14. HANDOVER FOR MICROCELLULAR NETWORKPARAMETERS

cellType Class 3 V7

Description: Type of the adjacent cell

Value range: [normalType / umbrellaType / microType]


Default value: normalType

Type: DP, Design

Rec. value: normalType

Used in: Microcellular Algo type A

Eng. Rules: To run a capture handover (umbrella to micro) on a neighbor, whichmust be microType, the bts must be declared as umbrellaType. It ispossible to manage a three layer network by declaring cell A and cellB as umbrellaType, neighbor B and neighbor C as microType for cell A, neighbor A as umbrellaType and neighbor C as microType for cellB, and finally neighbor B as umbrellaType for cell C.

See also chapter Minimum Time Between Handover

cellType Class 3 V7

Description: Type of the serving cell

Value range: [normalType / umbrellaType / microType]

Object: bts

Default value: normalType

Type: DP, Design

Rec. value: normalType


Eng. Rules: To run a capture handover (umbrella to micro) on a neighbor, whichmust be microType, the bts must be declared as an umbrellaType. Itis possible to manage a three layer network by declaring cell A andcell B as umbrellaType, neighbor B and neighbor C as microType forcell A, neighbor A as umbrellaType and neighbor C as microType forcell B, and finally neighbor B as umbrellaType for cell C.

Remark: The adjacent cell umbrella Ref attribute is defined at the OMC-R if the

cell is a microcell (cellType) and directed retry handovers areprocessed in BSC mode (directed-RetryModeUsed).




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microCellCaptureTimer Class 3 V8

Description: Time used to confirm a capture (signal strength stability) when using

microcell Algorithm type AValue range: Time = N multiplied by runHandOver .

According to microCellCaptureTimer value, N values are thefollowing:

[0 to 249] N = [0 to 249]

250 N = 512

251 N = 1024

252 N = 2048

253 N = 4096

254 N = 8192

255 N = 16384


Default value: 0

Type: DP, Design

Rec. value: 8s, whatever runHandOver value

(e.g. if runHandOver = 2 N = 8, if runHandOver = 1 N = 16)


Eng. Rules: Experiments done in urban areas show that a timer of 8 seconds to 10seconds allows a better use of the capture.

See also chapter Impact of the Averaging on the Handovers.

microCellStability Class 3 V8

Description: Strength Level Stability Criterion for Capture Algorithm A



Default value: 10 dB

Type: DP, Design

Rec. value: 63 dB


Eng. Rules: To allow handovers on capture this parameter has to be set at a value

greater than 0. A value of microCellStability equal to 63 dB has to beset first, because with such a value, the stability constraints arealways verified.

The value of this parameter can then be decreased case by case.




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5.15. DISTANCE MANAGEMENT PARAMETERS

callClearing Class 3 V7

Description: Maximum distance between MS and BTS before call is cleared

It is greater than msRangeMax.This distance defines the cell maximum coverage area.

Value range: [2 to 35] km (non-extended mode)

[2 to 120] km (extended mode)

Object: bts

Default value: 35 in non-extended mode, 90 in extended mode

Type: DP, Product

Rec. value: Depends on the environment, typical value = (1.5 * cell diameter)+ 2 km or best cell distance coverage server

Generaly for non-extended mode: 7 km for urban, 35 km for rural

Used in: Call Clearing Process (run by BTS) (Cc)

Eng. Rules: The value should be related to the current cell coverage. A margin istaken by using the 1.5 coefficient. A 2km margin is also considered tocompensate lack of mobile timing advance accuracy.

If the observation counter shows a high number of call clearings, itmay mean that handover parameters on that cell are too permissive orbadly tuned. At the OMC-R, a control exists: callClearing > msRangeMax

extended cell Class 2 V9

Description: Whether the cell is extended (up to 120 km large) or not

The cell working mode governs the upper limit of the followingattribute values (refer to theses entries in the Dictionary):

callClearing, msRangeMax, and rndAccTimAdvThreshold

attributes of the bts object

concentAlgoExtMsRange and concentAlgoIntMsRange attributes

of the associated handOverControl object if the bts object

describes a concentric cell

Value range: [true (extended) / false (normal)]

Object: bts

Default value: false



Used in:

Eng. Rules: Extended cells will be used to reach mobiles that are far from the BTS(in the case of sea shores and pleasure boats, for example).

In an extended cell, two consecutive time slots are reserved for eachchannel. The capacity is then decreased.

CAUTION! Up to V10, an extended cell cannot be concentric. Whatever the MS-BTS distance is, two consecutive time slots are reserved on Airinterface.

See also chapter SDCCH Dimensioning an TDMA Models.

CAUTION! GPRS/EDGE is not supported when extended cell feature is activated.




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msRangeMax Class 3 V7

Description: Maximum MS–to–BTS distance beyond, which a handover may betriggered. It can be set to 1 for a microcell and is less than callClearingin all cases.




Default value: 34 in non-extended mode, 89 in extended mode


Rec. value: = callClearing - 1 km

Used in: Handover condition for leaving a cell on distance

Eng. Rules: If the associated serving cell is a concentric cell, the followinginequality, that is not checked by the system, must be true (refer to

this entry in the Dictionary):concentAlgoExtMsRange ≤ concentAlgoIntMsRange ≤ msRangeMax

CAUTION! callClearing > msRangeMax is controled at the OMC level. It must beadapted to current cell extent in order to be an efficient preventivehandover. If value is too small, there is a big risk of ping-ponghandover.

CAUTION! Due to lack of mobile timing advance accuracy this parameter mustnot be set at a too low value (not < 2). Generaly for non-extendedmode (6 km for urban and 34 km for rural)

msBtsDistanceInterCell Class 3 V7

Description: Whether inter–bts handovers are allowed in a cell for distancereasons





Rec. value: enabled

Used in: Handovers screening

Handover condition for leaving a cell on distance

Eng. Rules: Due to the imprecision of some MS on Timing Advance (see chapterDistance - timing advance conversion) and due to the delay spread ina very urban environment, it is possible to set this parameter to“disabled” (in an urban environment). However, for all cells with aradius of more than 1 km, handover on distance must be authorized.




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preSynchroTimingAdvance Class 3 V10

Description: Pre-defined timing advance used in a pre-synchronized handover

procedure between the serving cell and this neighbor cell.Value range: [1 to 35] (km)


Default value: Refer to parameter synchronized

Type: DP, Design


Used in: Pre-synchronized HO

Eng. Rules: This value of timing advance is used when the parametersynchronized is set to “pre sync HO with timing advance”. Apredefined timing advance can be defined when phase 2 MSs alwayshandove from the serving cell to this neighbor cell approximately at

the same place (railway, highway).If the parameter synchronized is set to “presyncho HO, default timingadvance”, the default TA value is “-1” (554 m).If the parameter synchronized is set to “presyncho HO, with timingadvance”, the parameter preSynchroTimingAdvance must be tuned tothe estimated value of TA.See also chapter Synchronized HO versus Not Synchronized HO.

CAUTION! preSynchroTimingAdvance value is not controlled at the OMC-R

rndAccTimAdvThreshold Class 3 V8

Description: MS–to–BTS distance beyond which mobile access requests to a cellare refused.

It defines the maximum timing advance value accepted.The effective timing advance value is broadcast in the CHANNELREQUIRED message sent by the BTS to the BSC. If it is above theuser defined threshold, the BSC ignores the request.



Object: bts

Default value: 35 (non-extended cell), 90 (extended cell)


Rec. value: msRangeMax (= call clearing - 1km = 1.5* cell diameter + 2 km -1km)

Generally for non-extended mode: 6 km for urban, 35 km for rural

Used in: Request access command process (RA)

Eng. Rules: The maximum authorized value will inhibit the feature.

By adjusting the value to the size of the cell (see recommendedvalue), parasite RACH (noise which is decoded by the system like aRACH) are filtered. This avoids the unnecessary assigment ofSDCCH.For example, for small cells, if the value is 35 km, almost 30% of theRACHs are parasite. If the value is modified to 2, almost no parasitesRACH are detected.




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runCallClear Class 3 V7

Description: Number of “Measurement Results” messages that must be receivedbefore the call clearing algorithm in a cell is triggered

Value range: [1 to 31] SACCH frames (1 unit = 480 ms on TCHs, 470 ms on

SDCCHs)

Object: bts

Default value: 16

Type: DP, System

Rec. value: 16

Used in: Call Clearing Process (run by BTS) (Cc)

Eng. Rules: It is not necessary to run Cc too often, since those calls are going tobe ended anyway. Nevertheless, traffic out of a cell’s range interfereson other cells or timeslots.




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5.16. POWER CONTROL PARAMETERS

bsMsmtProcessingMode Class 2 V7

Description: Whether radio measurements collected by the mobiles for a cell areprocessed by the BTS or the BSC

Value range: [preProcessedMeasurementReporting (BTS) /basicMeasurementReporting (BSC)]

Object: bts

Default value: preProcessedMeasurementReporting

Type: DP, Product

Rec. value: preProcessedMeasurementReporting


Eng. Rules: Since radio measurements are always preprocessed by the BTS,

changing this attribute has no meaning.

bsPowerControl Class 3 V7

Description: Whether BTS transmission power control is allowed at cell level


Object: powerControl



Rec. value: enabled

Used in: Step by step Power control One shot power control Fast power control at TCH assignment Power Control (AMR)

Eng. Rules: Not useful for mono-TRX cells, because BTS power control on BCCHfrequency is not allowed.

CAUTION! During a measurement field campaign, it can be normal to disable thisfeature in order to have the real signal strength and not the adjustedone.

bsTxPwrMax Class 3 V7

Description: Maximum theoretical level of BTS transmission power in a cell

The BSC relays the information to the mobiles in the Abis CELLMODIFY REQUEST message.

Value range: [0 to 47] dBm


Default value: 43 dBm


Rec. value: depends on the equipment


Cabinet Output Power Setting




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Eng. Rules: This power is used to calculate the cabinet output power. It dependson the attribute “attenuation” of btsSiteManager objects (see chapterPr computation), because the value of the parameter “attenuation” isthen taken into account as DLU attenuation.

Remark: For a GSM 1900 network (standardIndicator of bts object set to

‘pcs1900’), the MD-R checks the following: bsTxPwrMax < 32 (dBm)when an edge frequency is defined for the cell (i.e. if the value isincluded in the cellAllocation attribute values).

Some bsTxPwrMax values are not compatible with the effective poweroutput by the BTS (see chapter Pr computation).

lRxLevDLP Class 3 V7

Description: Signal strength threshold in BTS–to–MS direction, below which thepower control function increases power. It is lower than uRxLevDLP.





Rec. value: -95 to -94 dBm (step by step)

-85 to -84 dBm (one shot)

Used in: Step by step Power control

One shot power control Fast power control at TCH assignment Power Control (AMR)

Eng. Rules: The difference between lower and upper thresholds must be greater

or equal to max (powerIncrStrepSize, powerRedStepSize), because itis controled at the OMC level.

lRxLevDLP > lRxLevDLH, up to V7, because power Control andhandover algorithms are decorrelated.

CAUTION! In case the AMR power control algorithm is activated ( refer to theamrReserved2 parameter) that parameter defines the threshold belowwhich the AMR power control is inhibited.

In that case the recommended values remain the same if the AMRpenetration is low, and the same + 2dB if the AMR penetration is high.

lRxLevULP Class 3 V7

Description: Signal strength threshold in MS–to–BTS direction, below which thepower control function increases power. It is lower than uRxLevULP.





Rec. value: -95 to -94 dBm (step by step)

-85 to -84 dBm (one shot)


One shot power control

Fast power control at TCH assignment Power Control (AMR)




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Eng. Rules: lRxLevULP > lRxLevULH, up to V7, because power Control andhandover algorithms are decorrelated.

CAUTION! In case the AMR power control algorithm is activated ( seeamrReserved2 parameter) that parameter defines the threshold belowwhich the AMR power control is inhibited.

In that case the recommended values remain the same if the AMRpenetration is low, and the same + 2dB if the AMR penetration is high.

lRxQualDLP Class 3 V7

Description: Bit error rate threshold in BTS–to–MS direction, above which thepower control function increases power. It is greater than or equal touRxQualDLP.



Default value: 0.4 to 0.8Type: DP, Optimization

Rec. value: 0.8 to 1.6 % (RxQual = 3 in GSM unit) without SFH

3.2 to 6.4 % (RxQual = 5 in GSM unit) with SFH



Eng. Rules: This value must be lower than lRxQualDLH in order to maintainpriority between power control and handover.

lRxQualULP Class 3 V7

Description: Bit error rate threshold in MS–to–BTS direction, above which thepower control function increases power. It is greater than or equal touRxQualULP.



Default value: 0.4 to 0.8






Eng. Rules: This value must be lower than lRxQualULH in order to maintainpriority between power control and handover.




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powerIncrStepSizeDL Class 3 V14

Description: Increment step size for downlink power control.

Value range: [2, 30] dB


Default value: 4 dB


Rec. value: 4 dB


Eng. Rules: A high step is required to be reactive in increasing the power whenentering an area where propagation is not acceptable.

A higher step (6 dB) is recommended for specific networks orenvironment (high speed trains for example).The attribute powerIncrStepSizeDL must verify: lRxLevDLP +

powerIncrStepSizeDL ≤ uRxLevDLP

CAUTION! Not used in one shot power control nor in AMR power control.

powerIncrStepSizeUL Class 3 V14

Description: Increment step size for uplink power control.



Default value: 4 dB


Rec. value: 4 dB


Eng. Rules: A high step is required to be reactive in increasing the power whenentering an area where propagation is not acceptable.

A higher step (6 dB) is recommended for specific networks orenvironment (high speed trains for example).The attribute powerIncrStepSizeUL must verify:lRxLevULP +powerIncrStepSizeUL ≤ uRxLevULP

CAUTION! Not used in one shot power control nor in AMR power control.

powerRedStepSizeDL Class 3 V14

Description: Decrement step size for downlink power control.



Default value: 2 dB


Rec. value: 2 dB


Eng. Rules: Small steps are enough to adapt two subsequent changes in qualityand strength. Moreover, calls become sensitive to low MS or BS

TxPower.




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The attribute powerIncrStepSizeDL must verify: uRxLevDLP –powerRedStepSizeDL ≥ lRxLevDLP

CAUTION! Not used in one shot power control.

powerRedStepSizeUL Class 3 V14

Description: Decrement step size for uplink power control.



Default value: 2 dB


Rec. value: 2 dB


Eng. Rules: Small steps are enough to adapt two subsequent changes in quality

and strength. Moreover, calls become sensitive to low MS or BStxPower.

The attribute powerRedStepSizeUL must verify: uRxLevULP –powerRedStepSizeUL ≥ lRxLevULP


runPwrControl Class 3 V7

Description: Number of Measurement Results messages that must be receivedbefore the power control algorithm in a cell is triggered.

Value range: [1 to 31] frames (1 unit = 480 ms on TCH, 470 ms on SDCCH)

Object: btsDefault value: 4

Type: DP, System

Rec. value: 2


Power Control (AMR)

Eng. Rules: The lowest is the parameter value, the best will be the reactivity;nevertheless, it is better to wait for the effect of MS power decreaseon the uplink quality.

uplinkPowerControl Class 3 V8

Description: Whether power control in the MS–to–BTS direction is authorized atcell level





Rec. value: enabled


Power Control (AMR)

Eng. Rules:




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uRxLevDLP Class 3 V7

Description: Upper strength threshold for BTS txpwr decrease for step by stepalgorithm (it is greater than IRxLevDLP)





Rec. value: = lRxLevDLP + Max (powerIncrStepSizeDL,powerRedStepSizeDL) typically


Eng. Rules: Difference between the lower and upper thresholds must be greater orequal to the maximum power step size.


uRxLevULP Class 3 V7

Description: Upper strength threshold for MS txpwr decrease for step by stepalgorithm (it is greater than lRxLevULP).





Rec. value: lRxLevULP + Max (powerIncrStepSizeUL, powerRedStepSizeUL)typically


Eng. Rules: Difference between the lower and upper threshold, must be greater orequal to the maximum power step size.


uRxQualDLP Class 3 V7

Description: Upper quality threshold to reduce BTS txpwr for step by step algorithm(it is lower than or equal to lRxQualDLP).








Eng. Rules: This value must be lower than lRxQualDLH in order to maintainpriority between power control and handover.





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uRxQualULP Class 3 V7

Description: Upper quality threshold to reduce MS txpwr for step by step algorithm

(it is lower than or equal to lRxQualULP).Value range: [less than 0.2, 0.2 to 0.4, 0.4 to 0.8, ... , 6.4 to 12.8, more than 12.8] %





1.6 to 3.2 % (RxQual = 4 in GSM unit) wtih SFH


Eng. Rules: This value must be lower than lRxQualULH in order to maintainpriority between power control and handover.

There is no reason why this value should differ from uRxQualDLP.CAUTION! Not used in one shot power control.




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5.17. TCH ALLOCATION MANAGEMENT PARAMETERS

accessClassCongestion Class 3 V9

Description: List of access classes that are not authorized in a cell during TCHcongestion phase (class 10 not included)

Value range: [0 to 9] User classes

[11 to 15] Operator classes

Object: bts

Default value: [0,1,2,3,4,5,6,7,8,9]

Type: DP, Design


Used in: Dynamic barring of access class (All_4)

V15.0 Changes of dynamic barring of access class (All_4)

Eng. Rules: Usually, in a low capacity cell (between 1 and 2 TRXs), many classesmust be forbidden in case of congestion (few resources available). Ina high capacity cell, only a few classes must be forbidden.

allocPriorityTable Class 3 V7

Description: Table of eighteen elements that define the internal priorities forprocessing TCH queued allocation requests for each external prioritydefined (among them, fourteen are GSM priorities)

TCH is always allocated using the internal priority.

Value range: [0 to 12]. “0” defines the highest priority.

Object: bts

Default value: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Type: DP, System

Rec. value: 0 2 2 2 2 2 2 2 2 2 2 2 2 3 0 4 2

0 8 9 10 11 12 2 2 2 2 2 2 2 2 3 0 4 2 for WPS use

Used in: Allocation and priority (run by the BSC) (All_1)

Queuing driven by the MSC (All_2) Queuing driven by the BSC (All_3) WPS – Queuing management

Eng. Rules: The default set means that all TCH allocation requests have the same

priority, which is equal to 0.When queuing is activated, set the following parameters in order notto disadvantage the interCell handover procedures:

Priority for interCell handover: 0

Priority for other procedures: ≠ 0

allocPriorityThreshold > 0

CAUTION! When WPS Queuing Management is activated, the WPS priorities (8to 12) have to be set as recommended, otherwise WPS queues will bemanaged like internal public queues.




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allocPriorityThreshold Class 3 V7

Description: Number of free TCHs needed for processing a TCH allocation request

with an internal priority higher than 1These channels are reserved to allocation requests with a maximuminternal priority (priority 0).The TCH allocation is performed according to this algorithm:

Nb of free TCH = 01 ≤ Nb of free TCH ≤

allocPriorityThresholdNb of free TCH >

allocPriorityThreshold

TCH requestof priority 0

queuing if defined orrejected

TCH allocated TCH allocated

TCH requestof priority > 0



TCH allocated

For GPRS with shared PDTCH, the allocation is performed accordingto this algorithm: free resources are composed of free TCH andshared PDTCH not already used by a GSM call:

Nb of free TCH = 01 ≤ Nb of free TCH ≤

allocPriorityThresholdNb of free TCH >

allocPriorityThreshold

TCH requestof priority 0


TCH allocated if TCHfree > 0

if preemption isauthorized and PCU

ACK, allocation of ashared PDTCH

if preemption is notauthorized or PCUNACK, queuing if

defined or rejected




if preemption is notauthorized or PCUNACK, queuing if

defined or rejected

TCH requestof priority > 0






if preemption is notauthorized or PCUNACK, queuing ifdefined or rejected



Type DP, Design

Rec. value: n, with n TRX


Queuing driven by the MSC (All_2) Queuing driven by the BSC (All_3)




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Eng. Rules: When TCH channels are reserved and the internal priority forassignRequest is ≠ 0, the capacity for incoming calls decreases:

Example:

1 TRX, 7 TCH, 2 % blocking rate, allocPriorityThreshold = 0,

capacity for incoming calls = 2,88 Erlang

1 TRX, 7 TCH, 2 % blocking rate, allocPriorityThreshold = 1,

capacity for incoming calls = 2,23 Erlang

Queuing spreads out the TCH allocation request. As incominghandover requests are not queued, such requests are disadvantaged. A solution is to reserve 1 TCH channel (for 1 or 2 TRXs) or 2 TCHchannels (for at least 2 TRX) for calls of internal priority 0, and set thepriority 0 for incoming handovers only.Note that when TCH channels are reserved for handovers, thecapacity for incoming calls decreases.

allocPriorityTimers Class 3 V7

Description: Table of timers defining the maximum waiting time of TCH allocationsrequest (public and WPS request), according to the internal priority.

Value range: [0 … 65535] for BSC3000

[0 … 2147483646] for BSC12000

Object: bts

Default value: 0 0 0 0 0 0 0 0 28 28 28 28 28

Type: DP, System

Rec. value: 5 0 5 5 0 0 0 0 28 28 28 28 28

Used in: Queuing driven by the MSC (All_2)

Queuing driven by the BSC (All_3) WPS – Queuing management

Eng. Rules: A high value of timer is not realistic, since a subscriber will not waitunless the last TCH is available quickly. The last five parameters inthe table (those set to 28) define the waiting time of WPS callsqueued.

See also chapter Directed Retry Handover Benefit




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allocWaitThreshold Class 3 V7

Description: Table of thresholds defining the maximum number of TCH allocation

requests queued (public and WPS), according to their internal priority. A TCH request of priority Pi, P0<Pi<P7, is queued if the total numberof requests of priority Pj, with j<i, already in the queue does notexceed the waiting threshold of the queue “i” (element “i” of theallocWaitThreshold table). A WPS request priority is queued according to the rules of WPSqueuing.

Value range: [0 to 63] MMI Range

Object: bts

Default value: 0 0 0 0 0 0 0 0 5 5 5 5 5

Type: DP, System

Rec. value: n 0 n n 0 0 0 0 5 5 5 5 5, with n = integer part of (number ofSDCCH subchannels / 2)



Eng. Rules: The maximum size in each queue must be lower than the number ofSDCCH channels in the cell.

For an incoming call, when the assignRequest is queued, it remainson the SDCCH subchannel.The last five parameters in the table are determining the maximumnumber of WPS calls of the same priority that can be queued.

allOtherCasesPriority Class 3 V7

Description: Index in the allocPriorityTable that defines the processing priority ofTCH allocation requests with cause “other cases”

This priority is used in primo–allocations or when an SDDCH cannotbe allocated for overload reasons.


Object: bts

Default value: 17

Type: DP, System

Rec. value: 16



Eng. Rules: The associated internal priority is > 0.

A TCH allocation request (in signaling mode) whose cause is “othercase” is acknowledged when at least allocPriorityThreshold + 1channels are free.Refer also to the allocPriorityTable parameter.




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answerPagingPriority Class 3 V7

Description: Index in the allocPriorityTable that defines the processing priority of

TCH allocation requests with cause “reply to paging”This priority is used in signaling mode on TCH only.


Object: bts

Default value: 17

Type: DP, System

Rec. valueb 16



Eng. Rules: The associated internal priority is > 0. A TCH allocation request (in signaling mode) whose cause is “othercase” is acknowledged when at least allocPriorityThreshold + 1channels are free.Refer also to the allocPriorityTable parameter.

assignRequestPriority Class 3 V7

Description: Index in the allocPriorityTable that defines the processing priority ofTCH allocation requests with cause “immediate assignment”

This priority is used when radio resource allocation queuing is notrequested by the MSC or not authorized in the BSS (refer to the

bscQueuingOption parameter).


Object: bts

Default value: 17

Type: DP, System

Rec. value: 17



Eng. Rules: When queuing driven by the MSC is used, this parameter is not

significant.It is recommended not to associate an internal priority equal to 0.There is no queuing for TCH in “signaling mode”.Refer also to the allocPriorityTable parameter.




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bscMSAccessClassBarringFunction Class 3 V9

Description: Enable or disable dynamic barring of access class at the bsc level


Object: bsc


Type: DP, Design

Rec. value: enabled, see Engineering Rules



Eng. Rules: Set to disabled, this parameter allows to inhibit the dynamic barring ofaccess class feature for the whole BSC whatever the values of theother parameters related to All_4 are.

If queuing or directed retry is activated, the following parameters mustbe used:

numberOfTCHQueuedBeforeCongestion

numberOfTCHQueuedToEndCongestion

bscQueuingOption Class 1 V7

Description: Whether radio resource allocation requests are queued in the BSCwhen no resources are available

If no resource is available when an allocation request is received and queuing is notallowed, the allocation request is refused immediately.

Value range: [allowed (MSC driven) / forced (O&M driven) / not allowed] allowed: resource allocation request queuing depends on the type

of operation and indicative items provided with the messages

received from the MSC.

forced: resource allocation request queuing depends on the type of

operation only.

not allowed: resource allocation request queuing is forbidden.

Object: signallingPoint

Default value: forced

Type: DP, Design

Rec. value: forced (O&M driven)allowed (MSC driven) for WPS use



Eng. Rules: When queuing is activated, the queued procedures (assignRequestand intraCellHO if OMC driven) statistically take advantage on theother procedures. If all the TCH channels are already allocated, thequeued procedures stay in the queue during a defined time (seeallocPriorityTimers), when the others are rejected.




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Suppose the operator expects to enable the queuing later. Due to theclass of the parameter bscQueuingOption, it is recommended not toset “not allowed”. Otherwise, the BSC will need to be switched off toimplement the feature.See also chapter Directed Retry Handover Benefit

CAUTION! WPS Queuing Management can be activated only ifbscQueuingOption is set to “allowed”, i.e if MSC can handle differentpriorities of assignement request.

btsMSAccessClassBarringFunction Class 3 V9

Description: Enable or disable dynamic barring of access class at the bts level


Object bts


Type: DP, DesignRec. value: See Engineering Rules



Eng. Rules: To enable dynamic barring of access class at the bts level, thisparameter and the bscMSAccessClassBarringFunction parameter ofthe corresponding bsc must be set to enabled.

This feature globally reduces the cell capacity.The fewer the number of TRXs on the cell, the more the capacity isreduced.

callReestablishmentPriority Class 3 V7

Description: Index in the allocPriorityTable that defines the processing priority ofTCH allocation requests with cause “call reestablishment”

This priority is used in primo–allocations or when an SDDCH cannotbe allocated for overload reasons.


Objectb bts

Default value: 17

Type: DP, System

Rec. value: 15



Eng. Rules: The value that must be given should correspond to a priority 0.

Refer to the allocPriorityTable parameter.




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cellBarQualify Class 3 V8

Description: Cell selection priority used in the C2 algorithm in Phase II

The information is broadcast to the mobiles at regular intervals on thecell BCCH.

Value range: [true (low priority) / false (normal priority)]

Object: bts

Default value: False


Rec. value: False

Used in: Selection or reselection between cells of current Location Area(Sel_1)

Additional reselection criterion (for phase 2) (Sel_3) New SYS INFO messages

Eng. Rules: refer to Sel_3 algorithm, see also chapter DualBand Networks.

cellBarred Class 3 V7

Description: Whether direct cell access are barred to mobiles

The information is broadcast to the mobiles at regular intervals on thecell BCCH.During a call, it is transmitted on a signaling link.If the attribute value is changed to “barred”, all in–progress calls cancontinue but the BSC will direct further mobile calls to another cell.

Value range: [barred / not barred]

Object: btsDefault value: not barred


Rec. value: not barred

Used in: Selection or reselection between cells of current Location Area(Sel_1)

Additional reselection criterion (for phase 2) (Sel_3)

Eng. Rules: refer to Sel_3 algorithm, see also chapter DualBand Networks.

channelType Class 2 V7

Description: Type of logical channel supported by a radio TS

Value range: [tCHFull / sDCCH / mainBCCH / mainBCCHCombined /bcchsdcch4CBCH / sdcch8CBCH / cCH (V12) / pDTCH (V12)]

Object: channel

Default value: None


Rec. value: None.

No recommended value is specified since this parameterdepends on the strategy of the operator.

Used in:

Eng. Rules: In the case of GSM, refer to chapter SDCCH Dimensioning an TDMAModels for the rules with SDCCH.




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emergencyCallPriority Class 3 V7

Description: Index in the table allocPriorityTable for a TCH allocation request

whose cause is “emergency call”This priority is used in primo–allocations or when an SDDCH cannotbe allocated for overload reasons.


Object: bts

Default value: 17

Type: DP, System

Rec. value: 15



Eng. Rules: The internal priority associated is 0. A TCH allocation request (insignaling mode) whose cause is “emergency call” is acknowledgedwhen at least 1 channel is free.

Refer also to the allocPriorityTable parameter.

interCellHOExtPriority Class 3 V7

Description: Index in the allocPriorityTable that defines the processing priority ofincoming inter–bss handovers in a cell

This priority is used when radio resource allocation queuing is notrequested by the MSC or not authorized in the BSS (refer to the

bscQueuingOption parameter).


Object: bts

Default value: 17

Type: DP, System

Rec. value: 15



Eng. Rules: The internal priority associated is 0. A TCH allocation request (in

signaling mode) on interBSC handover is aknowledged when at least1 channel is free.

When queuing is used, it is recommended to give the priority 0 andreserve the TCH channels (allocPriorityThreshold) since itdisadvantages requests that cannot be queued.Refer also to the allocPriorityTable parameter.




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interCellHOIntPriority Class 3 V7

Description: Index in the allocPriorityTable that defines the processing priority of

incoming intra–bss handovers in a cellThis priority is always used, whether radio resource allocation queuingis authorized in the BSS or not.


Object: bts

Default value: 17

Type: DP, System

Rec. value: 15



Eng. Rules: The internal priority associated is 0.

A TCH allocation request (in signaling mode) on intraBSC handover isaknowledged when at least 1 TCH is free.When queuing is used, it is recommended to give the priority 0 andreserve the TCH channels (allocPriorityThreshold) since itdisadvantages requests that cannot be queued.Refer also to the allocPriorityTable parameter.

intraCellHOIntPriority Class 3 V7

Description: Index in the allocPriorityTable that defines the processing priority of an

intra–bts handover in a cellThis priority is always used, whether radio resource allocation queuingis authorized in the BSS or not.


Object: bts

Default value: 17

Type: DP, System

Rec. value: 14


Queuing driven by the MSC (All_2)

Queuing driven by the BSC (All_3) Eng. Rules: Refer also to the allocPriorityTable parameter.




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directedRetryPrio V12

Description: Index in the allocPriorityTable that defines the processing priority for

directed retry handoversValue range: [0 to 17]

Object: bts

Default value:


Rec. value: 17

Used in: TCH Allocation Management

Eng. Rules: Refer also to the allocPriorityTable parameter.

intraCellQueuing Class 3 V8

Description: Whether intra–bts handover requests are queued for a cell. Thisparameter is significant only when queuing radio resource allocationrequests is allowed in the BSS.

Refer to the bscQueuingOption parameter.


Object: bts



Rec. value: Enabled


Queuing driven by the BSC (All_3)

Eng. Rules: None.

minNbOfTDMA Class 2 V7

Description: Minimum number of TDMA frames that must be working in order forthe cell itself to be working.

The frame carrying the cell BCCH must be among them and issuccessfully configured.

Value range: [1 to 16]Object: bts

Default value: 1


Rec. value: 1

Used in:

Eng. Rules: None.




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notAllowedAccessClasses Class 3 V7

Description: List of mobile access classes that are forbidden in the cell, exceptcase of congestion.

This attribute, together with the emergencyCallRestricted attribute,

allows to control access to a cell according to the service classesauthorized.

Value range: List of mobile access class:

[0 to 9]: user classes

[11 to 15]: operator classes

Object: bts

Default value: Leave the field empty

Type: DP,Operation

Rec. value: “null” (empty list)


Changes of dynamic barring of access class (All_4)

Eng. Rules: This parameter contains the list of forbidden access classes. Usuallyall users are authorized, in this case, the list must be empty.

numberOfTCHFreeBeforeCongestion Class 3 V9

Description: Minimum number of free TCHs which triggers the beginning of theTCH congestion phase and the beginning of the traffic overloadcondition

Value range: [0 to infinite]

Object: bts

Default value: 0

Type: DP, Design

Rec. value: 1 for cells with 1-2 TRXs

2 or 3 for cells with more than 3 TRXs


Changes of dynamic barring of access class (All_4) Handover for traffic reasons

Eng. Rules: Note that the congestion feature does not distinguish betweenreserved or unreserved TCHs. A reserved TCH is a TCH booked for apriority 0 procedure. Setting this parameter must consider the numberof reserved TCHs.

numberOfTCHFreeToEndCongestion Class 3 V9

Description: Threshold that gives the number of free TCHs, which triggers the endof TCH congestion phase and the end of the traffic overload condition.


Object: bts

Default value: 0

Type: DP, Design


3 or 4 cells with more than 3 TRXs




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Eng. Rules: numberOfTCHFreeToEndCongestion >numberOfTCHFreeBeforeCongestion

Note, this inequality is not checked at the OMC.

numberOfTCHQueuedBeforeCongestion Class 3 V9

Description: Maximum number of TCH allocation requests queued which triggersthe beginning of the TCH congestion phase and the beginning of thetraffic overload condition


Object: bts

Default value: 0

Type: DP, Design


3 or 4 cells with more than 3 TRXs



Eng. Rules:

numberOfTCHQueuedToEndCongestion Class 3 V9

Description: Maximum number of TCH allocation requests queued which triggersthe end of TCH congestion phase and the end of the traffic overloadcondition


Object: bts

Default value: 0

Type: DP, Design


2 or 3 for cells with more than 3 TRXs



Eng. Rules:




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otherServicesPriority Class 3 V7

Description: Index in the table allocPriorityTable for a TCH allocation request (in

signaling mode) whose cause is “other services”This priority is used in primo–allocations or when an SDDCH cannot be allocated for

overload reasons.


Object: bts

Default value: 17

Type: DP, System

Rec. value: 16



Eng. Rules: The internal priority associated is > 0. A TCH allocation request (insignaling mode) whose cause is “other services” is acknowledgedwhen at least allocPriorityThreshold + 1 channels are free.

Refer also to the allocPriorityTable parameter.

priority Class 2 V7

Description: Priority level of a TDMA frame for mapping TDMA onto TRXs.

At least minNbOfTDMA TDMA frames related to a cell must besuccessfully configured for the cell to be working.They include the TDMA frame carrying the cell BCCH and those with

the other priority(ies).


Object: transceiver

Default value:


Rec. value: See Engineering Rules

Used in:

Eng. Rules: Refer to section SDCCH Dimensioning and TDMA priorities.




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5.18. EMLPP RADIO RESOURCE PREEMPTION PARAMETER

Note that other parameters related to eMLPP Radio Resource Preemption

(emergencyThreshold and eMLPPThreshold) are only meaningful in GSM-R, therefore theyare not described in this document.

preemptionAuthor Class 3 V15

Description: This parameter activates or deactivates radio resource preemptioncapability in the BSS (used in the context of eMLPP supplementaryservice).

This parameter is available for both GSM-R and public GSM.

Value range: [forbidden, authorizedWithRelease, authorizedForcedHO]Object: signallingPoint

Default value: forbidden

Type: DP

Rec. value: see Eng Rules

Used in: eMLPP Preemption

Eng. Rules: preemptionAuthor = “forbidden” means that the BSC never performsradio resource preemption, whatever the priority and PCI/PVI flags’values.

preemptionAuthor = “authorizedWithRelease” means that the BSC isallowed to perform radio resource preemption if necessary and ifauthorised by the MSC.A successful preemption results in thepreempted call being released.

preemptionAuthor = “authorizedWithForcedHO” means the same thingas preemptionAuthor = “authorizedWithRelease” in the currentimplementation, despite the different name




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5.19. DIRECTED RETRY HANDOVER PARAMETERS

adjacent cell umbrella ref Class 3 V9

Description: Identifier of the adjacentCelHandOver object that describes theneighbor cell towards which a directed retry will be triggered in BSCmode


Object: bts

Default value:

Type: DP, Design

Rec. value: Identifier of the adjacentCellHandOver of the macrocell whichtotally covers the micro cell.

Used in: Directed Retry Handover: BSC (or local) mode

Eng. Rules: BSC mode is especially used in a two layer network. For micro cells,directed retry needs to be triggered towards the macro cell. However,if the recovering of each micro cell is good enough,adjacentUmbrellaRef can identify a micro cell.

To facilitate the procedure, the BCCH frequency of the target neighborcell must be in the reselection list.See also chapter Directed Retry Handover Benefit.

directedRetry Class 3 V9

Description: Minimum signal strength level received by the mobiles to be grantedaccess to the neighbor cell, used in processing directed retry

handovers in BTS mode



Default value: more than -48 dBm


Rec. value: = rxLevMinCell + 3 to 25 dB

Used in: Directed Retry Handover: BTS (or distant) mode

Eng. Rules: The choice of recommended value has to be done regarding thegeneral design of the network. A 3 dB margin must be considered asa minimum on a network to eliminate field strength bumps effect due

to multipath. However, this margin must be increased in an urbanenvironment or with the use of reuse pattern (overall for a 1X1pattern) because of the generated interference when the MS is not onthe best server cell.

See also chapter Directed Retry Handover Benefit.

CAUTION! Directed retry is not allowed between 2 zones of a concentric cell.

For a dual Band Network where one frequency band is privileged, it ispossible to set this parameter to a higher value in neighbour cellsbelonging to the low priority frequency band. Thus, this band will beunderprivileged. However, it will impact the directed retry formonoband MS on this band (less directed retry).




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intraBscDirectedRetry Class 3 V9

Description: Whether intra–bss directed retry handovers are allowed in a BSS


Object: bscDefault value: allowed

Type: DP, Design

Rec. value: allowed


Directed Retry Handover: BTS (or distant) mode

Eng. Rules: See also chapter Directed Retry Handover Benefit.


intraBscDirectedRetryFromCell Class 3 V9

Description: Whether intra–bss directed retry handovers are allowed in a cell


Object: bts

Default value: allowed


Rec. value: allowed


Directed Retry Handover: BTS (or distant) mode

Eng. Rules: If the value is “not allowed” then, the value ofintraBscDirectedRetryFromCell must be set to “not allowed” for theconcerned cells.

See also chapter Directed Retry Handover Benefit.


modeModifyMandatory Class 3 V9

Description: Whether a CHANNEL MODE MODIFY message should be sent to themobile after a directed retry handover in the BSS

Value range: [used (yes) / not used (no)]

Object: bsc

Default value: not used


Rec. value: not used

Used in: Directed Retry Handover




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Eng. Rules: In the early days of GSM, this parameter was useful for mobilesbelonging to specific brands, that used not to be able to switch directlyfrom signaling (SDCCH) to speech (TCH) when executing a Directedretry procedure. For that reason, this parameter used to be set to"used" so that a Channel Mode Modify procedure could be done,

forcing an explicit change of channel upon the mobile. However,today, as these mobile bugs have now presumably been corrected,with few or no faulty mobiles remaining in the field today, thesystematic invokation of the CMM procedure is no longer required.Setting to "used" may, in addition, have detrimental side-effects forsome kinds of inter-cell handovers (problem noted on instances ofintercell 3G-2G Handovers) which will systematically invoke aChannel Mode Modify. Therefore it is recommended to set thisparameter systematically to value “not used”.




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5.20. CONCENTRIC CELL PARAMETERS

biZonePowerOffset Class 3 V12

Description: Offset added in calculation formula to draw up the list of eligible cellsfor handover towards a dualband, dualcoupling, or concentric cellinner zone to take into account the difference of propagation modelsbetween the two bands of the cells and the difference of transmissionpower between TRXs of the two zones due to either BTSconfiguration or coupling.



Default value: if main band = 850 MHz biZonePowerOffset = 3 dB

if main band = 1900 MHz biZonePowerOffset = -3 dB




Direct TCH allocation Concentric/DualCoupling/DualBand Cell Handover

Eng. Rules: Used for intercell handover to control whether the inner zone is“eligible” or not.

to inhibit Direct TCH Allocation on an adjacent cell (when the

adjacent cell is declared as monozone / concentric / dualband /

dualcoupling) biZonePowerOffset(n) = 63

to allow Direct TCH Allocation on an adjacent cell (when the

adjacent cell is declared as concentric / dualband / dualcoupling)biZonePowerOffset(n) =concentAlgoExtRxLev(n) - rxLevMinCell(n)

Note: Shall be 63 for a monozone adjacent cell.

The higher (in positive) is the value, the more difficult it will be tohandover in the inner zone of the adjacent cell.It is advised to set a value higher than the max offset (in rxLevDLband 0) corresponding to the biggest difference of coverages betweenthe 2 bands (for the adjacent cell) otherwise an intercell handover tothe inner zone would be wrongly decided.

CAUTION! If HO decision is made toward the inner zone of a multizone cell, thenrelated EXP1XX(n) is computed with biZonePowerOffset(n).

See also chapters Concentric Cells and DualBand Networks.




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biZonePowerOffset Class 3 V12

Description: Power offset between inner and outer TRXs of the handOverControl

object of a dualband, dualcoupling, or concentric cell.Value range: [-63 to 63] dB


Default value: if main band = 850 MHz, biZonePowerOffset = 3 dB

if main band = 1900 MHz, biZonePowerOffset = -3 dB




Direct TCH allocation Concentric/DualCoupling/DualBand Cell Handover

Eng. Rules: monozone cell:

biZonePowerOffset = 63

concentric cell:

biZonePowerOffset = zone Tx powermax reduction

concentric cell with HePA only on outer zone:


dualband cell (main band = 850 or 900 MHz):


dualband cell (main band = 1800 or 1900 MHz):

biZonePowerOffset = - 6 dualcoupling cell:

biZonePowerOffset = zone Tx powermax reduction = coupling lossesdifference between inner and outer zone

dualband + dualcoupling cell combination:

biZonePowerOffset = coupling losses + propagation losses

CAUTION! When using dualcoupling cell DLU attenuation should be NULL andcompensated by the zone Tx power max reduction, see concentriccell parameter

Note: Shall be 63 for a monozone adjacent cell.

CAUTION! If HO decision is made in the small zone of a multizone cell then

related EXP2xx(n) = hoMarginxx(n) + biZonePowerOffset.See also chapters Concentric Cells and DualBand Networks.




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concentAlgoExtMsRange Class 3 V9

Description: MS to BTS distance below which a handover is requested from the

large zone to the small zone if the level criteria is verifiedValue range: [1 to 34] km (non-extended mode)



Default value: 1

Type: DP, Design

Rec. value: 34

Used in: Direct TCH Allocation

Concentric cell / dualcoupling cell intracell handovers

Eng. Rules: The calculated distance between the MS and the BTS is based on

timing advance (TA), which has an accuracy of ± 3 bits (correspondingto more than 1,5 km), thus not very useful in urban areas where thecell size is relatively small and multipath affect the MS_BS distance.

However this parameter can be useful in rural areas or suburbanareas, and concentAlgoExtMsRange should respect following rules:

concentAlgoExtMsRange = concentAlgoIntMsRange - 1 km

concentAlgoExtMsRange < concentAlgointMsRange

concentAlgoExtMsRange < msRangeMax

Note: 34 disable the parameter since condition is always fullfilled.


concentAlgoIntMsRange Class 3 V9

Description: MS to BTS distance from which a handover from the small zone to thelarge zone will be requested




Default value: 34

Type: DP, Design

Rec. value: 34

Used in: Concentric cell / dualcoupling cell intracell handovers Eng. Rules: The calculated distance between the MS and the BTS is based on

timing advance (TA), which has an accuracy of ± 3 bits (correspondingto more than 1,5 km), thus not very useful in urban areas where thecell size is relatively small and multipath affect the MS_BS distance.

However this parameter can be useful in rural areas or suburbanareas, and concentAlgoIntMsRange should respect following rules:

concentAlgoIntMsRange > concentAlgoExtMsRange

concentAlgoIntMsRange < msRangeMax

Note: 34 disable the parameter since condition is always fullfilled.





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concentAlgoExtRxLev Class 3 V9

Description: The Downlink level of the MS signal strength above which a handover

is requested from the large zone to the small zoneValue range: [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm


Default value: - 95 to - 94

Type: DP, Design



Concentric/DualCoupling/DualBand Cell Handover Concentric cell / dualcoupling cell intracell handovers

Eng. Rules: The recommended value depends on the network design. Depending

on capacity distribution between inner and outer zone, CPT can beused to match the RxLev DL number of samples toconcentAlgoExtRxLev, which defines when users interzone handoverfrom outer to inner zone, i.e. inner zone traffic load.

The following rules shall be respected:

concentAlgoExtRxLev > concentAlgoIntRxLev

concentAlgoExtRxLev≤ rxLevMinCell + biZonePowerOffset


concentAlgoExtRxLevUL Class 3 V18

Description: The uplink level of the MS signal strength above which a handover isrequested from the large zone to the small zone



Default value: - 95 to - 94

Type: DP, Design



Concentric/DualCoupling/DualBand Cell Handover Concentric cell / dualcoupling cell intracell handovers

Eng. Rules: The recommended value depends on the network design. Dependingon capacity distribution between inner and outer zone, CPT can be

used to match the RxLev DL number of samples toconcentAlgoExtRxLev, which defines when users interzone handoverfrom outer to inner zone, i.e. inner zone traffic load.

The following rules shall be respected:

concentAlgoExtRxLevUL > concentAlgoIntRxLevUL





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concentAlgoIntRxLev Class 3 V9

Description: Downlink Level of the MS signal strength below which a handover is

requested from the small zone to the large zoneValue range: [less than -110, -110 to -109, ... , -49 to -48, more than -48] dBm


Default value: less than -110

Type: DP, Design


Used in: Concentric/DualCoupling/DualBand Cell Handover


Eng. Rules: In order to avoid unnecessary ping-pong interzone HO a HysteresisMargin should be added:

concentAlgoIntRxLev = concentAlgoExtRxLev - biZonePowerOffset- Hysteresis Marginwhere recommended Hysteresis Margin = 4 dBSee also chapters Concentric Cells and DualBand Networks.

concentAlgoIntRxLevUL Class 3 V18

Description: Uplink Level of the MS signal strength below which a handover isrequested from the small zone to the large zone



Default value: less than -110Type: DP, Design




Eng. Rules: In order to avoid unnecessary ping-pong interzone HO a HysteresisMargin should be added:

concentAlgoIntRxLevUL=concentAlgoExtRxLevUL-biZonePowerOffset- Hysteresis Marginwhere recommended Hysteresis Margin = 4 dB

In addition concentAlgoIntRxLevUL has to be set regardingconcentAlgoIntRxLev and the path balance of the cellExample concentAlgoIntRxLev = -85 path balance =4, thereforeconcentAlgoIntRxLevUL = -89





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directAllocIntFrRxLevUL Class 3 V18

Description: uplink RxLev threshold above which a TCH-FR could be allocated inthe small zone of a multi-zone cell (in conjunction withdirectAllocIntFrRxLevDL).



Default value: -84 to -83

Type: DP, Design




Eng. Rules:

directAllocIntFrRxLevDL Class 3 V18

Description: downlink RxLev threshold above which a TCH-FR could be allocatedin the small zone of a multi-zone cell (in conjunction withdirectAllocIntFrRxLevUL).



Default value: -79 to -78

Type: DP, Design




Eng. Rules:




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concentric cell Class 2 V9

Description: Whether the cell is monozone, concentric, dualband or dualcoupling

A concentric, dualband, or dualcoupling cell describes a combinationof two transmission zones, the outer (or large) zone and the inner (orsmall) zone. The inner zone is entirely included in the outer zone. A dualband cell is a particular type of concentric cell for which GSM900 and GSM1800 (or GSM 850 and GSM1900) TRXs/DRXs coexistand share the same BCCH. A dualcoupling cell is a particular type of concentric cell for which theTRXs/DRXs are combined with two types of combiners.For concentric configurations (concentric, dualband or dualcoupling),a TDMA frame belongs to one zone or the other, but never to both.

Value range: [monozone / concentric / dualband / dualcoupling]

monozone: normal cell

concentric: two concentric transmission zones dualband: two concentric transmissions zones with GSM 900

TRXs/DRXs for the one and GSM 1800 TRXs/DRXs for the other

dualcoupling: two concentric transmission zones with TRXs/DRXs

combined with one type of combiner for the one and with another

type of combiner for the other

Object: bts

Default value: monozone



Used in: Concentric/DualCoupling/DualBand Cell Handover Eng. Rules:

concentric cell:

It is possible to allocate directly a TCH in the innerzone for call set-upor HO and to reuse the same frequency in both zones, and hoppingconcerns the total available number of frequencies. A cell configuration with HePA only on outer zone is concentric cell,not a dualcoupling cell.

dualband cell:

The dualband combining into one cell allows to save up to oneSDCCH in particular configurations, the combining of GSM 900 / GSM1800 (or GSM 850 / GSM 1900) resources into one pool allows to

increase the traffic capacity.

CAUTION! dualband is not supported on S4000 with DCU2/DCU4, S4000 withDCU2, S4000 with DCU4

dualcoupling cell:

The DLU attenuation shall be used: so configure the “attenuation”parameter (btsSiteManager object) to null, configure the max powerfor the cell to the desired max power (power for the outer zone) andconfigure zone Tx power max reduction for the inner zone to the deltavalue.

CAUTION! dualcoupling is not supported on mixed DCU4 or DRX transceiverarchitecture.





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small to large zone HO priority Class 3 V12

Description: External priority of inter-zone handovers from the inner zone to the

outer zone in a concentric cell. This attribute is defined if theassociated bts object describes a concentric cell.



Default value: 17

Type: DP

Rec. value: 14


Queuing driven by the MSC (All_2) Queuing driven by the BSC (All_3) Concentric cell / dualcoupling cell intracell handovers

Eng. Rules: Refer also to the allocPriorityTable parameter.

transceiver equipment class Class 2 V9

Description: Class of a TRX/DRX.

The class of a TRX/DRX sets, among others, its maximumtransmission power. The attribute possible values have the followingmeaning:

Class 1 corresponds to GSM 850/900 class 5 or GSM 1800/1900

class 1 (20W to 40W transmitters)

Class 2 corresponds to GSM 900 class 6 which is not supported orGSM 1800/1900 class 2 (10W to 20W transmitters)

Value range: [0 (reserved) / 1 / 2]

Object: transceiverEquipment

Type: DP

Rec. value: monozone: 1

concentric cell: outer=1, inner=1

dualband cell: outer=1, inner=2

dualbcoupling cell: outer=1, inner=2


Eng. Rules: When dual band is used, the class of a TRX/DRX enables todistinguish which DRX and which TDMA are used in the outer zone orinner zone.

Class 1 corresponds to to a TDMA in the frequency band carryingBCCH so belonging to transceiverZone = 0 (large/outer zone).Class 2 corresponds to a TDMA in the frequency band not carryingBCCH so belonging to transceiverZone = 1 (small/inner zone).If the TRX/DRX is partnered with a TDMA frame, its class matches theTRX/DRX class allotted to the zone to which the TDMA frame belongs(refer to the next parameter).

Note: In case of concentric cell configuration, setting inner and outer class to“1” allows a reconfiguration of TRX/DRX from the inner to the outer if

needed.




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transceiver equipment class V9

Description: Class of the TRX/DRXs partnered with the TDMA frames of the zone.

The class of a TRX/DRX sets, among others, its maximumtransmission power. Refer to the previous parameter.


Object: transceiverZone

Type: DP

Rec. value: monozone: 1

concentric cell: outer=1, inner=1

dualband cell: outer=1, inner=2

dualbcoupling cell: outer=1, inner=2


Eng. Rules: When dual band is used, the class of a TRX/DRX enables todistinguish which DRX and which TDMA are used in the outer zone orinner zone.

Class 1 corresponds to to a TDMA in the frequency band carryingBCCH so belonging to transceiverZone = 0 (large/outer zone).Class 2 corresponds to a TDMA in the frequency band not carryingBCCH so belonging to transceiverZone = 1 (small/inner zone).

Note: In case of concentric cell configuration, setting inner and outer class to“1” allows a reconfiguration of TRX/DRX from the inner to the outer ifneeded.

transceiverZone Class 2 V12

Description: Identifier of the transceiverZone object that defines the zone to whicha TDMA frame belongs in a concentric cell.

The transceiverZone objects are only significant for the bts objectsthat describe concentric cells. Two transceiverZone objects arecreated for each created concentric bts object; one describes thelarge or outer transmission zone, and the other describes the smallorinner transmission zone.

Value range: [0 (large outer zone) / 1 (small or inner zone)]


Type: DP

Rec. value: 0 for outer zone

1 for inner zone


Eng. Rules: When a concentric/dualband/dualcoupling cell is created thetransceiverZone outer zone must set to “0” and the transceiverZoneinner zone must be set to “1”.

It is not applicable for monozone cells.




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zone Tx power max reduction Class 2 V9

Description: Attenuation vs bsTxPwrMax that defines the maximum TRX/DRX

transmission power in the zoneValue range: large zone = [0] dB, small zone = [1 to 55] dB


Default value: 0 dB

Type: DP, Design


Used in: Concentric cell / dualcoupling cell intracell handovers

Eng. Rules:

concentric cell:

zone Tx Power Max Reduction(outer) = 0

zone Tx Power Max Reduction(inner) ≤ zone Tx Power MaxReduction(outer)(zone Tx Power Max Reduction(inner) = 0 is recommanded)

dualband cell (homogeneous coupling):

zone Tx Power Max Reduction(outer) = 0zone Tx Power Max Reduction(inner) = 1

dualcoupling cell:

zone Tx Power Max Reduction(outer)=0zone Tx Power Max Reduction(inner)=3 simulates the D/H2Dconfigurationzone Tx Power Max Reduction(inner)=4 simulates the H2D/H4Dconfiguration

CAUTION! when using dualcoupling cell DLU attenuation should be NULL andcompensated by the zone Tx power max reduction, see concentriccell parameter





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5.21. INTERFERENCE LEVEL PARAMETERS

averagingPeriod Class 2 V7

Description: Number of SACCH multiframes over which the interference levels areaveraged. This averaging will be performed immediately before thetransmission of the RESOURCE INDICATION message.

This attribute, together with the “thresholdInterference” attribute,allows users to manage interferences in radio cells. Refer to this entryin the Dictionary.

Value range: [0 to 255] SACCH frame (1 unit = 480 ms on TCH, 470 ms onSDCCH)


Default value: 20

Type: DP, System

Rec. value: 20

Used in: Radio channel allocation

Interference Management (BTS and BSC) (If)

Eng. Rules: Performing this message broadcast has a great impact on the systemload and should not be done too often.

Reducing this value speeds-up the channel allocation algorithm, sinceit checks temporary channel interference non frequently. However, themain purpose of this algorithm is to take into account long terminterference and not short term interference which do not have astatistically large impact on call quality.




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radChanSelIntThreshold Class 3 V8

Description: Maximum interference level on free radio channels, below which the

channels are ranged in the group of allocation priority channelsThe information is used to first allocate the free channels with thelowest interference level. The levels depend on thethresholdInterference attribute value defined for the cell. Refer to thisentry in the Dictionary.The BSC distributes the free radio channels among two groups:

The first group contains the list of channels with a measured

averaged interference level equal to or lower than the defined

level.

The second group contains the list of channels with a measured

averaged interference level higher than the defined level, and

recently released channels for which no measurement is available.

Four resource pools are defined for each SDCCH or TCH type ofchannel:

low interference level radio channels that are authorized to hop

low interference level radio channels that are not authorized to hop

high interference level radio channels that are authorized to hop

high interference level radio channels that are not authorized to

hop



Default value: 1


Rec. value: 3

1 (for 1X1 & 1X3)

Used in: Interference Management (BTS and BSC) (If)

Eng. Rules: A high value for this parameter means a tolerant interference sorting.

It is easier to change the value of this pointer than to tune thethresholds themselves since the thresholds are used in the lower layerof signal processing at the BTS.The radChanSellIntThreshold counter can be set after interferencecounters monitoring. Ideally, it should depend on the average traffic

load expected on the cell and on the interference distribution.With low Traffic per TCH, radChanSellIntThreshold can be set to 1.This means that the selection of the non interefered channels is veryselective. The few TCH selected are sufficient for the traffic to becarried. RadChanSellIntThreshold can be decreased to 1 when using1X1 or 1X3 reuse pattern in order to use as more BCCH resources aspossible.

With high Traffic per TCH, radChanSellIntThreshold can be set to 4.This means MS will get allocated to a channel regardless of theinterference as long as there are resources available.




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thresholdInterference Class 2 V7

Description: List of four thresholds defined in ascending order, used to sort idlechannels on the basis of measured interference levels

This attribute, together with the averagingPeriod attribute, allowsmanaging interferences in a radio cell. The classification is used bythe radio resource allocator.For each idle radio channel, the BTS permanently measures thesignal strength level RXLEV.When averagingPeriod “Measurement results” messages have beenreceived, the L1M function in the BTS calculates interference levelaverages, sorts the idle channels according to the five definedinterference levels, and sends the information to the BSC.

Level 0 corresponds to: RXLEV < threshold 1

Level 1 corresponds to: threshold 1 < RXLEV < threshold 2



Level 4 corresponds to: threshold 4 < RXLEV

Value range: [-128 to 0] dBm


Default value: -100 -90 -80 -70


Rec. value: -114, -112, -108, -100

Used in: Radio channel allocation

Interference Management (BTS and BSC) (If)

Eng. Rules: Those values define 5 interference level ranges, so free channelclassification can be displayed at the OMC-R level. The setting of thethreshold Interference level should be linked to the interference leveldistribution in the cell. As a first definition, thresholds can be evenlydistributed over the defined range.




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5.23. BSS TIMERS

bssMapT1 Class 1 V7

Description: A interface timer triggered by the BSC in the BSSMAP managementprocedure.

It is started on transmission of BLOCK or UNBLOCK by the BSC andcancelled on receipt of BLOCK ACKNOWLEDGE or UNBLOCK ACKNOWLEDGE sent by the MSC.

Value range: [2 to 300] seconds

Object: bsc

Default value: 5

Type: DP, System

Rec. value: 5, 60 (if using DMS switch)

Used in:Eng. Rules:

bssMapT12 Class 1 V7


This timer is used with a Phase I MSC only. It is started ontransmission of RESET CIRCUIT by the BSC and cancelled on receiptof RESET CIRCUIT ACKNOWLEDGE sent by the MSC.


Object: bsc

Default value: 5

Type: DP, System

Rec. value: 5, 60 (if using DMS switch)

Used in:

Eng. Rules:


Description: An interface timer triggered by the BSC in the BSSMAP management

procedure.It is started on receipt of RESET sent by the MSC. On elapse, theBSC sends RESET ACKNOWLEDGE to the MSC.


Object: bsc

Default value: 32

Type: DP, System

Rec. value: 32

Used in:

Eng. Rules:




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Description: A interface timer triggered by the BSC in the BSSMAP management

procedure.This timer is used with a Phase II MSC only. It is started ontransmission of RESET CIRCUIT by the BSC and cancelled on receiptof RESET CIRCUIT ACKNOWLEDGE sent by the MSC.


Object: bsc

Default value: 32

Type: DP, System

Rec. value: 32

Used in:

Eng. Rules:



It is started on transmission of CIRCUIT GROUP BLOCK or CIRCUITGROUP UNBLOCK by the BSC and cancelled on receipt of CIRCUITGROUP BLOCK ACKNOWLEDGE or CIRCUIT GROUP UNBLOCK ACKNOWLEDGE sent by the MSC.


Object: bsc

Default value: 32

Type: DP, System

Rec. value: 32

Used in:

Eng. Rules:

bssMapT4 Class 1 V7


It is started on transmission of RESET and cancelled on receipt ofRESET ACKNOWLEDGE sent by the MSC. On elapse, the BSCsends RESET.


Object: bsc

Default value: 60

Type: DP, System

Rec. value: 60

Used in:

Eng. Rules:




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bssMapT7 Class 1 V7

Description: A interface timer triggered by the BSC in the BSSMAP management

procedure.It is started on transmission of HANDOVER REQUIRED andcancelled on receipt of HANDOVER COMMAND, RESET, RESETCIRCUIT, CLEAR COMMAND or HANDOVER REQUIRED REJECT.


Object: bsc

Default value: 7


Rec. value: 7

Used in:

Eng. Rules:

bssMapT8 Class 1 V7


It is greater than t3103 for each cell managed by the BSC. It is startedon transmission of HANDOVER COMMAND and cancelled on receiptof CLEAR COMMAND sent by the MSC or HANDOVER FAILUREsent by MS.


Object: bsc

Default value: 15


Rec. value: 15

Used in:

Eng. Rules: It is greater than t3103 for each cell managed by the BSC.

bssMapTchoke Class 1 V7

Description: A interface timer triggered by the BSC in the handover managementprocedure.

It is started by the BSC when the last neighbour cell in the list isrejected. On timer elapse, the BSC asks the BTS to provide a new listof eligible cells.


Object: bsc

Default value: 4

Type: DP, System

Rec. value: 4

Used in:

Eng. Rules: It is strongly recommended to keep this value.




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bssSccpConnEst Class 1 V7

Description: A interface timer triggered by the BSC in the handover management

procedure.It is set on transmission of CONNECTION REQUEST and cancelledon receipt of CONNECTION CONFIRM or CONNECTION REFUSED.

Value rang: [5 to 360, by steps of 5] seconds


Default value: 5

Type: DP, System

Rec. value: 5

Used in:

Eng. Rules: A high value is dangerous in case of slowing down on A interface.

Then, the minimum value (5 s) must be chosen for this parameter; it isstrongly recommended not to modify this value.

t3101 Class 3 V7

Description: BSC timer triggered during the immediate assignment procedure. Usethe suggested system value.

It is set on transmission of CHANNEL ACTIVATION by the BSC andcancelled on receipt of ESTABLISH INDICATION sent by the BTS.


Object: bts

Default value: 3Type: DP, System

Rec. value: 3

Used in:

Eng. Rules: Most of the time, the timer expires in the case of double allocation (i.e,when two RACHs are sent by the same mobile to the network). Thehigher the timer is the longer unnecessary signaling resources arereserved. Up to 30% of signaling resources are allocated for a secondRACH for phase 1 MS according to numberOfSlotsSpreadTrans (32).To optimize signaling resources (especially in case of Queuing), itcould be useful to decrease the timer value. The minimum timebetween the two messages is 600 ms and the maximum for a lightly

loaded BSS is almost 1.8 seconds when MS is answering.




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t3103 Class 3 V7

Description: BSC timer triggered during the handover procedure. Use the

suggested system value.It is set on transmission of HANDOVER COMMAND by the BSC andcancelled on receipt of either HANDOVER COMPLETE orHANDOVER FAILURE sent by the MS (intra–bss handover), orCLEAR COMMAND sent by the MSC (inter–bss handover). At expiryof T3103, the channel is released.

Value range: [2 to 255] seconds (t3103 < bssMapT8)

Object: bts

Default value: 5 seconds


Rec. value: 9 seconds

Used in:

Eng. Rules: The longest procedure (inter BSS handover) is taken as an example.The timer is set on receipt of the HO command and reset on clearcomplete. It means that as long as the timer runs, 2 channels arekept: one on the originating BSC and one on the target BSC. If thetimer is too long, two resources are used which can be a bad in caseof capacity problems.

Tests showed that t3103 set to 9 seconds offers the best compromisebetween the execution of the procedure and the hold of ressources.

t3107 Class 3 V7

Description: BSC timer triggered during the assignment command procedure. Usethe suggested system value.

It is set on transmission of ASSIGN COMMAND by the BSC andcancelled on receipt of either ASSIGN COMPLETE or ASSIGNFAILURE sent by MS.


Object: bts



Rec. value: 10 seconds in a network without any capacity problems.

If not, the value can be decreased. The minimum theoreticalvalue is 5 seconds.

Used in:

Eng. Rules: At expiry of the timer, the mobile is assumed to be lost and itsresource can be used by another mobile. Mobile on SDCCH is aconstraining case: the timer T200 leads to a 230 ms wait instead of180 ms on TCH, before repeating a message. If no message isrepeated, this procedure lasts about 1 second. However, if the radiolink is bad, it is necessary to repeat some messages. The maximumtime before resetting t3107 is approximately 5 seconds: after this time,the timer will expires: no new message will be received to reset t3107.

The default value of 10 seconds is then a good value to ensure that

the link is not cut too early.




Nortel confidential


t3109 Class 3 V7

Description: BSC timer triggered during the SACCH deactivation procedure. Usethe suggested system value.

It is set on receipt of DEACTIVATE SACCH ACKNOWLEDGE sent by

the BTS and cancelled on receipt of RELEASE INDICATION sent bythe BTS. If the timer expires, a RF CHANNEL RELEASE message issent to the BTS and a RF CHANNEL RELEASE ACK is expected.Mobiles comply with system operating conditions when the counter(S) associated with SACCH messages is assigned a value below orequal to t3109.

Value range: [2 to 255] seconds (t3109 ≥ radioLinkTimeout)

Object: bts



Rec. value: 12 seconds (related to radioLinkTimeOut value)

Used in:

Eng. Rules: On receipt of the Deactivate SACCH message, the radio link controlalgorithm will lead to a decrease on the value of the‘radioLinkTimeOut’ timer and this on MS side or on BTS sideaccording to the situation. t3109 added to t3111 must be greater thanradioLinkTimeOut and greater than the time corresponding to rlf1:t3109 ≥ radioLinkTimeOut

If t3109 is too small, the ressources could be allocated even ifradiolinkTimeOut did not reach zero yet.

CAUTION! When AMR is activated that parameter should be set to 17.

t3111 Class 3 V7

Description: BSC timer triggered during the radio resource clearing procedure. Usethe suggested system value.

It is set on receipt of RELEASE INDICATION sent by the BTS. Onelapse, the BSC sends RF CHANNEL RELEASE.


Object: bts


Type: DP, System


Used in:

Eng. Rules: This timer is used to delay the channel deactivation afterdisconnection of the main signalling link. Its purpose is to allow timefor the possible repetition of the disconnection by the BTS to the MS.

After Release Indication, resources are kept until t3111 expires. Incase of capacity problems, t3111 must be as little as possible. Thesmallest possible value is 2 seconds (range 2-255 seconds).Theminimum theoretic value is 5 times the repetition time which is lessthan 2 seconds No advantage has been found to have a higher valuethan the smallest possible one.This timer is also used in the formula to compute the preemtion timer :Tpreempt = Tdeactack + 4* T3111




Nortel confidential


t3122 Class 3 V7

Description: Minimum time that mobiles must wait before issuing a channel

allocation request when an immediate assignment has failed. In asimilar way, in GPRS mode, this value is indicated in the Packet Access Reject (PAREJ) to inform the MS with the waiting time beforesending a new Channel Request. The timer is called T3172 in GPRSmode, with T3172 = T3122.


Object: bts




Used in:

Eng. Rules: This value is broadcast to the mobile stations. When an immediateassignment reject command is received (when no SDCCH and noTCH in signalling mode is available or when the A-interface is down),mobile stations wait t3122 seconds before sending the request again.In case of BSC Overload, t3122 is automatically increased ordecreased between its value set by O&M and 30s according to aspecific algorithm.

This parameter can be used to solve a problem of a load pick. Byincreasing the value, the access to the network is regulated.

timerPeriodicUpdateMS Class 3 V7

Description: Time between two location update requests

Value range: [0 to 255] 1/10th of hour. “0” means that no periodic location update isrequested.

Object: bts

Default value: 60


Rec. value: 10 (not loaded network)

20 (loaded network)

Used in:

Eng. Rules: Location updatings are performed when initiating a call or when

entering a new location area in idle mode. When those events do notoccur, timerPeriodicUpdateMS is used to ensure a maximum timebetween two location update requests. The value of this timer shouldbe set regarding the value of the same timer used in the switch(‘attach mobile audit’ for a DMS)

If the value chosen is low, the load of the BSC is severely increased.On the contrary, a too high value would lead to a smaller reactivity ofthe mobile (e.g. if a mobile is in a hole of coverage and a shortmessage is sent to it, it will be aware of it only at the next locationupdate which could be several hours later). A good trade-off is 2hours.




Nortel confidential


5.24. PAGING PARAMETERS

delayBetweenRetrans Class 2 V8

Description: Number of occurences of a paging sub–group that separates twotransmissions of the same paging message.


Object: bts

Default value: 0


Rec. value: 0

Used in: Paging command repetition process (run by BTS) (Pag_rep)

Eng. Rules: The recommended value is 0 because the time between two pagingcommands broadcast must not be too long, otherwise there is a risk of

double allocation. This phenomenon occurs when the suscriberanswers and hangs up very quickly. In that case, the mobile is readyto receive a new paging message, for example the previous one if it isresent. The value of this parameter is linked to the values of thenbOfRepeat and retransDuration parameters. Furthermore, thefollowing inequality, that is not checked by the system, must be true:

retransDuration ≥ (delayBetweenRetrans + 1) x nbOfRepeat See also chapter GSM Paging Repetition Process Tuning.

maxNumberRetransmission Class 3 V8

Description: Maximum number of RACH burst retransmissions allowed in a call in

case of non-system response. The information is broadcast to themobiles at regular intervals on the cell BCCH. It defines the maximumnumber of times a mobile can renew access requests to the BTS onRACH.

Value range: [one / two / four / seven]

Object: bts

Default value: two


Rec. value: two in non-interfered areas

four in interfered areas

Used in: Request access command repetition process (RA_rep) Eng. Rules: In interfered areas, it is necessary to repeat RACHs because of bad

conditions. Even if it increases a little overall noise, the gain indecreasing the number of RACHs not received should be significant(under study). In non-interfered areas, the value of ‘two’ is sufficient.‘one’ is not advised because mobile stations can be in holes ofcoverage due to multipath fading and, in these cases, at least oneretransmission is necessary.





Nortel confidential


nbOfRepeat Class 2 V8

Description: Maximum number of times that paging messages are repeated to

mobiles that belong to the same paging sub-groupIt is set to “3” in former BSS versions (static configuration parameter).The following inequality, that is not checked by the system, must betrue (refer to these entries in the Dictionary):retransDuration ≥ (delayBetweenRetrans + 1) x nbOfRepeat


Object: bts

Default value: 3




Eng. Rules: The value of 3 ensures a good quality of service. With less repetition,paging messages can be lost, and, as the repetitions are performedsystematically, a signicantly higher value would increase the load ofthe system and the risk to page a mobile twice. The value of thisparameter is linked to the values of the delayBetweenRetrans andretransDuration parameters.

That parameter can be tuned regarding the paging parameters andthe TDMA configuration, but very cautiously with some metricmonitoring (see chapter GSM Paging Repetition Process Tuning)

noOfBlocksForAccessGrant Class 2 V7

Description: Number of CCCH blocks not used for paging

A BCCH is combined when it shares the same radio time slot with fourSDCCHs, which can include a CBCH (refer to the channelType entryin the Dictionary). In that case, the attribute value is no greater than to2 (the value must be checked by users).

Value range: [0 to 2] if the cell uses a combined BCCH,

[1 to 7] otherwise.“0” means that PCH blocks are used for sending immediateassignment messages as and when needed.

Object: bts

Default value: 0

Type: DP, System

Rec. value: 0 if no SMS-CB or SMS-CB with combined BCCH

1 if SMS-CB with non-combined BCCH

> 0 if SI2Quater or/and SI13 on ext BCCH are activated

Used in: Paging command Process (Pag)

Effects of SMS-Cell Broadcast Use on “noOfBlocksForAccessGrant” SI2Quater & SI13 on Extended or Normal BCCH

Eng. Rules: See also chapter GSM Paging Repetition Process Tuning.




Nortel confidential


noOfMultiframesBetweenPaging Class 2 V7

Description: Number of occurrences of a paging sub–group

The greater this number, the greater the number of paging sub–groups.

Value range: [2 to 9] multi–frame of fifty-one frames

Object: bts

Default value: 6


Rec. value: 6 for rural environments

2 or 4 for urban environments

Used in: Paging command Process (Pag)

Eng. Rules: This parameter has an impact on the use of mobile batteries

(determine when an MS needs to listen to paging channels) and onreselection selectivity. For this operation, frequency of measurementsperformed on idle neighbours thanks to the formula: mesurementsdone every Max (5 seconds, ((5*nb of idle neighbors + 6) DIV 7) *noOfMultiframesBetweenPaging /4).

Regarding mobile batteries, a value of 6 is sufficient to have a trade-off between the saving of energy and effective paging. In ruralenvironments, the maximum size of reselection list is usually 4/5. 5seconds is then the maximum in the formula, so it does not slow downthe reselection mechanism. The value of 6 is then advised.In urban environments, the size of the list is a bit higher. Furthermore,in this kind of environment, reselection reactivity is a key issue. Theway to avoid having more than 5 seconds in the formula is to

decrease noOfMultiframesBetweenPaging to 2 or 4 even if itincreases battery consumption. Some studies are in progress todetermine the value with more accuracy.

See also chapter Effects of “noOfMultiFramesBetweenPaging” onMobile Batteries and Reselection Reactivity.




Nortel confidential


numberOfSlotsSpreadTrans Class 3 V7

Description: Number of radio time slots over which RACH transmission access are

spread in a random way to avoid collisionsThe information is broadcast to the mobiles at regular intervals on thecell BCCH. In the event of non-system response, the mobile willrenew the RACH bursts after a randomly defined period that varieswith numberOfSlotsSpreadTrans.MS Phase 1The time T between two transmissions of the same RACH burst is thefollowing:T= [D + (N+1) x 4.615]ms

D is the maximum system response pending time:

D= 250 ms for BCCH not combined (i.e. 55 time slots)D= 350 ms for BCCH combined (i.e. 77 time slots)

N is the randomly number generated by the mobile in the range [0to numberOfSlotsSpreadTrans-1]

4.615 ms is the time occupied by a time slot.

MS Phase 2The time T between two transmissions of the same RACH burst is thefollowing (whatever the BCCH is combined or not):T= 4.615 x [S+(N + 1)] ms where

S is a parameter depending on the BCCH configuration and on the

value of numberOfSlotsSpreadTrans (see table hereafter)

N is the randomly number generated by the mobile in the range [0

to numberOfSlotsSpreadTrans-1]

4.615 ms is the time occupied by a time slot.

numberOfSlotsSpreadTransS on non-combined

BCCHS on combined

BCCH

3, 8, 14, 50 55 41

4, 9, 16 76 52

5, 10, 20 109 58

6, 11, 25 163 86

7, 12, 32 217 115

Value range: [3 to 12, 14, 16, 20, 25, 32, 50] time slots

Object: bts

Default value: 32


Rec. value: 32

Used in: Request access command repetition process (RA_rep)

Eng. Rules: From Rec 04.08, numberOfSlotsSpreadTrans has a different meaningfor phase 1 and phase 2 mobiles. For phase 1 mobiles, if the value istoo small, two resources may be allocated to the same mobile (doubleallocation). For phase 2 mobiles, it is different. The best trade-off is totake “32” which is very good for phase 2 mobiles and not too bad forphase 1 mobiles.

The choice will depend on the quantities of GSM phase 1 and GSMphase 2 mobiles.




Nortel confidential


For Mobile phase 1, numberOfSlotsSpreadTrans = 50 leads to thelower double allocation rate.For Mobile phase 2, numberOfSlotsSpreadTrans = 6, 7, 11, 12, 25, 32(respectively 5, 10, 20) for BCCH combined (respectively BCCH notcombined) leads to the lower double allocation rate.

Therefore, for a network that handles a combination of both types ofmobiles, numberOfSlotsSpreadTrans should be set to 32 (defaultvalue).


pagingOnCell Class 3 V9

Description: Enable or disable paging requests in a cell


Object: bts



Rec. value: enabled but can be disabled on special occasions (seeEngineering Rules)

Used in: PCH and RACH channel control

Eng. Rules: When pagingOnCell is set to disabled, the BSC does not send anyPAGING_COMMAND to the cell. This feature is used when operatorswant to forbid mobile terminated call set-up in specific cells. It can beuseful during special events or in places like cinemas, theaters...

retransDuration Class 2 V8

Description: Maximum number of occurrences of a same paging sub-group thatseparates the first and the last transmissions of the same pagingmessage.


Object: bts

Default value: 10


Rec. value: 10


Eng. Rules: If many paging commands must be broadcast, repetitions of oldpaging messages are delayed because fresh paging has a higherpriority. Therefore, repetitions could be so delayed that it leads todouble paging. By setting this parameter to an accurate valueretransDuration , the risk of sending very old paging messages islimited. Anyway, the value of this parameter is linked to the ones ofnbOfRepeat and retransDuration. Furthermore, the followinginequality, that is not checked by the system, must be true:

retransDuration ≥ (delayBetweenRetrans + 1) x nbOfRepeat





Nortel confidential


5.25. FREQUENCY HOPPING PARAMETERS

bscHopReconfUse Class 1 V8

Description: Whether frequency hopping reconfiguration is authorized in BTSs thatuse cavity coupling

When frequency reconfiguration is authorized, it allows toautomatically reconfigure the hopping sequence whenever afrequency is lost or recovered in the BTS.This parameter is only useful if there is at least one BTS with cavitycoupling in the BSS. Otherwise its effect is neutral regardless of thevalue.

Value range: [true / false]

Object: bsc

Default value: true

Type: DP, Design

Rec. value: true for a BSC that manages at least one BTS using cavitycoupling

The value (true or false) is indifferent for a BSC that managesonly BTS with hybrid coupling

Used in: Reconfiguration procedure

Eng. Rules: If the value is ‘True’ then the value of btsHopReconfRestart (btsobject) must be true in case of cavity coupling in the BTS.

However, when enabling frequency hopping, it is advised to use

hybrid coupling and synthesized frequency hopping.

In order to facilitate the further use of frequency hopping in the

network, the parameter bscHopReconfUse can be set to “True”,

even if frequency hopping is not used yet.

btsHopReconfRestart Class 2 V8

Description: Whether hopping frequency reconfiguration is authorized on TXrestarts in a cell

Value range: [true / false]

Object: bts

Default value: true


Rec. value: true (for a BTS using cavity coupling)

false (for a BTS using hybrid coupling)


Eng. Rules: If the value is ‘True’ then the value of bscHopReconfUse must be true.

However, when enabling frequency hopping, it is advised to use

hybrid coupling and synthesized frequency hopping.

With cavity coupling, in order to facilitate the further use of

frequency hopping in the network, the parameter

btsHopReconfRestart can be set to “True”, even if frequency

hopping is not used yet.




Nortel confidential


btsIsHopping Class 2 V7

Description: Whether frequency hopping is allowed in a cell

Value range: [hopping / noHopping / hoppingWithCarrierFilling /noHoppingWithCarrierFilling]

Object: bts

Default value: Hopping

Type: DP, Design

Rec. value: Hopping

Used in: Frequency Hopping

Eng. Rules: The two main advantages of using Frequency Hopping are interfererand frequency diversities. Enabling frequency hopping allows to adaptand maximize the frequency reuse efficiency by maximizing thecapacity in terms of offered Erlang/MHz/km². Moreover, enabling

frequency hopping makes easier the task of frequency planning andTRXs addition. Although when using DTX there is a few number ofRxQual measurements, there is no need to disable handovers onquality criteria, as no degradation was observed.

CAUTION! When TRX are hopping, it is highly recommended to modify someTDMA configuration. Channel SDCCH must be set on time slot 1 ofthe concerned TDMA. Moreover this modification can be introducedbefore enabling frequency hopping.

CAUTION! It is also recommended not to use Power Control with FrequencyHopping in case of cavity couplers. Indeed, with cavity couplers, theBCCH frequency can be part of the Mobile Allocation List (that is notpossible in case of Hybrid couplers) and then the gap between the

emitted power of two adjacent bursts could be at its maximum.Remark: Except this particular case (cavity coupler + FH + PWC) there is no

restriction in combining Frequency hopping with Power Control.

btsThresholdHopReconf Class 2 V8

Description: Minimum number of frequencies that must be working in a cell to allowfrequency hopping reconfiguration. If this attribute defines the nominalnumber of cell frequencies, the reconfiguration process is deactivated.Refer to the btsHopReconfRestart parameter.




Rec. value: 1


Eng. Rules: This parameter is checked before reconfiguration is started, for cavitycoupling. If there are less remaining frequencies than the value of thisparameter, the cell is deconfigured. The minimum value (1) allows acell to be reconfigured even if there is only one frequency stillavailable.




Nortel confidential


cellAllocation Class 2 V7

Description: List of no more than 64 frequencies allocated to a cell in the network

frequency band.Normally, the maximum number of frequencies that can be set up withthis parameter is 64 per frequency band. However, due to SI13 sizeconstraints, when GPRS or EDGE is activated in the cell and there isat least one hopping data TDMA, the limitation becomes a maximumof 55 frequencies (in V15.0 and V15.0.1) ,52 frequencies (in V15.1and V15.1.1), 49 frequencies (from V16).By definition, all cells covered by a given radio site use the samefrequency band defined by the type of the network (standardIndicator ). All cells declared as neighbor cells of a serving cell use the samefrequency band as the serving cell.

Value range: [1 to 124] (GSM 900 network),

[975 to 1023] & [0 to 124] (E-GSM network),[955 to 1023] & [0 to 124] (GSM-R network),[512 to 885] (GSM 1800 network),[512 to 810] (GSM 1900 network)[128 to 251] (GSM 850 network)

Object: bts

Default value:



Used in:

Eng. Rules: This list must include all the frequencies used by TRX of the cell, even

the BCCH frequency and shall respect following rules: With cavity couplers, two (2) consecutive frequencies must be

spaced of at least 600 kHz in order to avoid interference

With hybrid couplers, considering UL power control activated:

in case of intra cell and intrasite configuration Nortel recommends

400kHz frequency spacing between TRX with or without frequency

hopping.

in case of intersite configuration, 200kHz frequency spacing are

necessary between TRX with or without frequency hopping.

These frequency spacings (400kHz in intrasite and intracell, 200kHz

in intersite) guarantee a minimum of 12dB in C/I. This can providecertain quality of service. With particular applications (e.g. EDGE), an

upper frequency spacing is needed (600kHz for EDGE).

It is recommended to declare only 1 hopping frequency list by band

(the use of the frequency band is optimal with all hopping

frequencies in the same list and it is much easier for OAM).

If at least one of the cell allocation ARFCN is in the range [975;

1023] & [0], the BCCH should be in that range also (this monoband

EGSM cell does not support monoband PGSM MS nor dualband

PGSM/DCS1800 MS), else BCCH should be a PGSM one.




Nortel confidential


CAUTION! When setting CellAllocation, a check is performed at OMCR in order toverify the number of frequencies. This number is limited by the spreadof frequencies

• if 1 =< spread of frequencies =< 112Then max number of frequencies = 64

• if 113 =< spread of frequencies =< 128

Then max number of frequencies = 29





The spread of frequencies is the maximal distance between the valueof frequence calculed as (Fmax – Fmin +1).This spread of frequencies

verification is performed for each band separately. For standardindicators like e-gsm and r-gsm, which have 2 ranged bands, thefollowing must be taken into account:

For E-GSM the range is [0..124]U[975..1023] ; so by realigning thefrequence the result is [975…1022, 1023, 1,..124]. the distance forexample100 and 1000 is 125 (not 901) because:

100 belongs to [0...124] spread of frequencies is 101

1000 belong to [975…1023] spread of frequencies is 24

fhsRef Class 2 V7

Description: Identifier of the frequencyHoppingSystem object that defines thefrequency hopping management parameters for the radio time slot

Setting this attribute and the maio attribute allows the time slot to obeyfrequency hopping laws.


Object: channel

Default value:



Used in:

Eng. Rules: It is advised to use only one (1) fhsRef per cell (when the Mobile Allocation is the same for all its TRX), because it is time saving forcreation at the OMC.




Nortel confidential


hoppingSequenceNumber Class 2 V7

Description: Hopping sequence number used by a radio time slot which obeys

frequency hopping laws.Select different HSNs for nearby cells that use the same set offrequencies.


Object: frequencyHoppingSystem

Default value:



Used in: Synthesised frequency hopping

Eng. Rules: In case of synthesized frequency hopping, whatever the fractional

reuse pattern for TCH, using a unique HSN per site allows to avoidfrequency collisions. However, it leads to a specific MAIO plan, morerestricting than with the use of different HSN in cells (needs morefrequencies). Indeed, the frequency load would be higher withdifferent HSN. But it is possible to reach the maximum fractional load(value limited by RF constraints to 16,6 % for 1X1 pattern and 50 %for 1X3 pattern in case of no intra-site collision). When intra-sitecollision is allowed, field experience has shown that with anappropriate tuning of the parameters, 1X1 can go up to 20% fractionalload and 1X3 up to 58% while keeping a very good quality for theoffered capacity.) with a unique HSN per site and then systematicallyavoiding frequency adjacencies.

See also chapter General Rules For Synthesised Frequency Hopping

maio Class 2 V7

Description: Index in the list of frequencies allotted to a radio time slot, whichobeys frequency hopping laws.

Setting this attribute, together with the fhsRef attribute, allows the timeslot to obey frequency hopping laws.

Value range: [0 to N-1] N is the number of frequencies allotted to the time slot.

Object: channel

Default value:




Eng. Rules: The MAIO must be different for each TRX within a cell in order toavoid frequency collision. If the Mobile Allocation contains adjacentfrequencies, the difference between two TRX MAIO within a cell mustbe greater or equal than two (2).

However, for a 1X3 pattern, it is possible to use the same MAIOsequence in all cells of a same site. Moreover, for such a pattern, ifeach list of MA frequencies does not contain adjacent frequencies,adjacent MAIO can be used.For a 1X1 pattern, different MAIO for each TRX must be used and noadjacent MAIO if there are adjacent frequencies in the MA list.

See also chapter General Rules For Synthesised Frequency Hopping




Nortel confidential


mobileAllocation Class 2 V7

Description: List of frequencies allocated in the network frequency band to a radiotime slot which obeys frequency hopping laws.

Normally, the maximum number of frequencies that can be set up withthis parameter is 63 i.e. 64 – BCCH frequency. However, due to SI13size constraints, when GPRS or EDGE is activated in the cell andthere is at least one hopping data TDMA (carrying at least onePDTCH), the limitation becomes a maximum of 55 – n frequencies (forV15.0 and V15.0.1) or 52 – n frequencies (for V15.1 and V15.1.1),or49 – n frequencies (from V16) where n is the number of non-hoppingfrequencies in the cell.


[975 to 1023] & [0 to 124] (E-GSM network),[955 to 1023] & [0 to 124] (GSM-R),[512 to 885] (GSM 1800 network),[512 to 810] (GSM 1900 network)[128 to 251] (GSM 850 network).

Object: frequencyHoppingSystem



Baseband Frequency Hopping


Eng. Rules: This list must include all the hopping frequencies used by a TRX. Asthe first TRX of a cell does not hop, it is not related to a MA (TRX

channels frequency is BCCH).The following TRXs may have a common MA containing all thehopping frequencies (not including the BCCH frequency).

With cavity couplers, two (2) consecutive frequencies must be

spaced of at least 600 kHz in order to avoid interference, because

of material constraints.

With hybrid couplers, considering UL power control activated:

in case of intra cell and intrasite configuration Nortel recommends

400kHz frequency spacing between TRX with or without frequency

hopping.

in case of intersite configuration, 200 kHz frequency spacing are

necessary between TRX with or without frequency hopping.

These frequency spacings (400kHz in intrasite and intracell, 200kHz

in intersite) guarantee a minimum of 12dB in C/I. This can provide

certain quality of service. With particular applications (e.g. EDGE), an

upper frequency spacing is needed (600kHz for EDGE).

It is recommended to declare only 1 hopping frequency list by band

(the use of the frequency band is optimal with all hopping

frequencies in the same list and it is much easier for OAM).




Nortel confidential


trafficPCMAllocationPriority Class 2 V9

Description: Allocation priority of a TDMA frame on the covering site PCMs

This attribute is used in case of Abis PCM reconfiguration.


Object: transceiver

Default value:


Rec. value: 255 for the TDMA supporting the BCCH

0 for the others

Used in:

Eng. Rules: see chapter SDCCH Dimensioning and TDMA priorities.

zoneFrequencyHopping Class 2 V9

Description: Whether frequency hopping is authorised in the zone.

If frequency hopping is not allowed in a zone, a channel objects thatdescribe the radio time slots of the TDMA frames used in the zonecannot be allowed to hop.

Value range: [hopping / not hopping]


Default value: not hopping

Type: DP


Used in:

Eng. Rules: In case of a dualband cell and if PDTCHs are configured on the innerzone, that parameter must be set to “not hopping” on thetransceiverZone corresponding to the inner zone.

In any other case that parameter must be set to “hopping”.

zoneFrequencyThreshold Class 2 V9

Description: Minimum number of frequencies needed to allow frequencyreconfiguration in the zone.



Default value: 1

Type: DP

Rec. value: TBD

Used in:

Eng. Rules:




Nortel confidential


5.26. BSC LOAD MANAGEMENT PARAMETERS

processorLoadSupConf Class 3 V8

Description: Threshold used in the load control algorithm by the BSC

Value range: [0] The only accepted value is 0 (outOfRangeError).

Object: bsc

Default value: 0


Rec. value: 0

Used in: Mechanism defined

Eng. Rules:

CAUTION! This parameter is valid for BSC12000 only.

estimatedSiteLoad Class 3 V15

Description: This parameter is used:

at site creation, in order to preset the erlang consumption of the

new Cell Group

ortherwise, in order to set the erlang consumption

Value range: [0 to 1100] erlangs. 1100 is the internal erlang capacity of a TMU2.

Object: btsSiteManager

Default value: 0

Type: DP


Used in: Evolution of Load Balancing

Eng. Rules: It is usually recommended to try to set the estimatedSiteLoad of a siteat the creation of this site (with the maximum configuration wanted forthis site) to be sure that at this time the global dimensioning of theBSC is correct.

It may also help in handling exceptional events on some parts ofthe network.




Nortel confidential


5.27. DUALBAND CELL PARAMETERS

early classmark sending Class 3 V10

Description: Whether Early classmark sending procedure initiated by a multibandmobile and/or a 2G-3G mobile is allowed.

The information is broadcast to the mobiles at regular intervals on thecell BCCH (SYSTEM INFORMATION n°3).

Value range: [Not Allowed, Allowed]

Object: bts

Default value: Not Allowed

Type: DP, Design

Rec. value: Allowed

Used in: Modified SYS INFO 3

Location Services GSM to UMTS handover (v17)

Eng. Rules: When this parameter is set to “allowed”, the mobile sends theClassmark_Change message just after the SABM and UA framesexchanged during the Immediate_Assignment procedure. Thismessage enables interband handover procedures (handovers on TCHand SDCCH, Directed Retry); Morever this parameter allows themobile to send its capacity downlink Advanced Receiver performance.In GSM cells where handover to UTRAN is possible, or UTRANmeasurement reporting is expected from the mobile, the "earlyclassmark sending" must also be requested from the mobile.

Therefore, if the operator is interested to have the SAIC mobile

penetration, it is recommended to set this parameter to “Allowed”In single band networks where no handover to 3G is required, “earlyclassmark sending” will be set to “not allowed”.In dual-band networks and in networks where handover to 3G may berequested, then early classmark sending will be set to “allowed”.

multi band reporting Class 3 V10

Description: Indication of the number of cells to be reported for each GSMfrequency band in multiband operation. This parameter is used bothfor normal and enhanced measurement reporting.

Value range: [0 : “no outband cell is favoured” / 1 : “1 strongest outband cell isfavoured” / 2 : “2 strongest outband cells are favoured” / 3 : “3strongest outband cells are favoured”

Object: bts

Default value: 0 : “no outband cell is favoured”


Rec. value: “two strongest outband cells are favoured” (case of privilegedband)

”no outband cell is favoured” (case of no privileged band)

Used in: Multiband reporting

Enhanced Measurement Reporting (EMR)





Nortel confidential


Eng. Rules: For values indicating the one (1), two (2) or three (3) strongest cellsout band, the multiband MS respectively reports the one, two or threestrongest allowed cells outside the current frequency band. Theremaining space in the report (at least 5, 4 or 3 cells) is used to giveinformation about cells in the current frequency band. If there are still

some remaining positions, they are used to report cells outside thecurrent frequency band.

When the operator wants to privilege one of the frequency band, it isadvised to report two (2) cells outside the current frequency band, forcells in the privileged frequency band. Then, neighbour cells in thepriority frequency band will be privileged. Actually, if multibandReporting is set to “1”, the risk is to report five (5)priority frequency band neighbour cells with a bad quality or signalstrength (near priority frequency band boundaries for example) andone (1) good neighbour cell in the low priority frequency band, butunder congestion. Thus the MS will not make a handover toward agood neighbour cell and the quality of service may be impacted.For cells outside the privileged frequency band, it is advised to report

three (3) cells outside the current frequency band. Thus, it ensures thereport of all (if less than 3) or at least three (3) neighours in the priorityfrequency band.In case no frequency band is preferred, the report of the “the sixstrongest cells” allows to make a handover toward the best neighbourcell, whatever the current cell is.

In case of 2G-3G handover being enabled, and EMR disabled (use ofnormal measurement reporting), it is necessary to exercise cautionwhen setting the parameters fDDMultiRatReporting andmultiBandReporting . These parameters define the number of UTRANcells and non-serving band GSM cells, respectively, that must beincluded by the mobile in the list of strongest cells in the measurement

report. Therefore it leaves (6 - fDDMultiRatReporting -multiBandReporting ) spaces for the serving band GSM cells.Therefore, if EMR is disabled, it is recommended not to exceedfDDMultiRatReporting = 2 and multiBandReporting = 2.

standard indicator AdjC Class 3 V10

Description: Type of network in which this neighbour cell is working

Value range: [gsm / extended gsm / dcs1800 / pcs1900 / R gsm / gsmdcs / dcsgsm/ gsm850 / gsm850pcs / pcsgsm850]

Object: adjacentCellHandover

Default value: gsm


Rec. value: extended gsm if available in the network. See Engineering Rules

Used in: Oher procedures (Dual Band Handling)

Eng. Rules: The indicates standard indicator must have the same value inadjacentCellHandover or adjacentCellReselection objects and in theassociated neighbour bts object.

Refer to the standardIndicator parameter engineering rules to getmore information about neighbours management.

CAUTION! “gsmdcs” and “dcsgsm” are only available for S8000 DRX transceiverarchitecture.

“eGSM” is only available for S8000 CBCF transceiver architecture.




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standard indicator AdjC Class 3 V10

Description: Type of network in which this neighbor cell is working

Value range: [gsm / extended gsm / dcs1800 / pcs1900 / R gsm / gsmdcs (V12) /dcsgsm (V12) / gsm850 / gsm850pcs / pcsgsm850]

Object: adjacentCellReselection

Default value: gsm


Rec. value: extended gsm if available in the network. See Engineering Rules

Used in: Oher procedures (Dual Band Handling)

Eng. Rules: The standard indicator must have the same value inadjacentCellHandover or adjacentCellReselection objects and in theassociated neighbour bts object

Refer to the standardIndicator parameter engineering rules to getmore information about neighbours management.

CAUTION! “gsmdcs” and “dcsgsm” are only available for S8000 DRX transceiverarchitecture.

“eGSM” is only available for S8000 CBCF transceiver architecture.

bCCHFrequency Class 3 V7

Description: Radio frequency allocated to a neighbour cell BCCH in the networkfrequency band.

The information is broadcast on the serving cell SACCH.


[512 to 885] (DCS 1800 network),[512 to 810] (PCS 1900 network),[955 to 1023] & [0 to 124] (R–GSM network),[975 to 1023] & [0 to 124] (E–GSM network),[128 to 251] (GSM 850 network).


Type: DP

Rec. value:

Used in:

Eng. Rules:




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Description: Radio frequency used for selection and reselection management. The

information is broadcast on the serving cell BCCH.Value range: [1 to 124] (GSM 900 network ),

[512 to 885] (DCS 1800 network),[512 to 810] (PCS 1900 network),[955 to 1023] & [0 to 124] (R–GSM network),[975 to 1023] & [0 to 124] (E–GSM network).[128 to 251] (GSM 850 network)

Object: adjacentCellReselection

Type: DP

Rec. value:


Eng. Rules:

Note: An adjacentCellReselection object can use the same BCCH as theserving cell to which it is associated. This allows a mobile toimmediately recover the cell on which it was “camping” after beingswitched off, then switched back on, and is especially useful in theselection process.


Description: Radio frequency allocated to a cell BCCH (Broadcast ControlCHannel) in the network frequency band.

The information is broadcast on the cell SACCH.The BCCH frequency is automatically assigned to the radio time slotcarrying the cell BCCH when the cell is brought into service(absoluteRFChannelNo attribute of the channel object describing thecarrier TDMA frame TS0). It is broadcast to the radio time slotwhenever modified.The BCCH is used by the BTS for broadcasting cell related systeminformation to MS, such as frequency band and list of frequencychannels used, authorized services and access conditions, list ofneighbour cells, and radio parameters (maximum transmissionstrength, minimum reception strength, etc).

Value range: [1 to 124] (GSM 900 network ),

[512 to 885] (DCS 1800 network),

[512 to 810] (PCS 1900 network),[955 to 1023] & [0 to 124] (R–GSM network),[975 to 1023] & [0 to 124] (E–GSM network).[128 to 251] (GSM 850 network)

Object: bts

Type: DP

Rec. value:

Used in:

Eng. Rules: If at least one of the cell allocation ARFCN is in the range [975; 1023]& [0], the BCCH should be in that range also (this monoband EGSMcell does not support monoband PGSM MS nor dualband

PGSM/DCS1800 MS), else BCCH should be a PGSM one.




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standardIndicator Class 2 V10

Description: Type of network in which the cell is working

From the value given to this attribute, the OMC–R determines thenetwork frequency band and the frequencies that can be used by allradio entities (cells and radio time slots) in the related site.

Value range: [gsm / extended gsm / dcs1800 / pcs1900 / R gsm / gsmdcs (V12) /dcsgsm (V12) / gsm 850 / gsm850pcs / pcsgsm850]

Object: bts

Type: DP

Rec. value:

Checks:

GSM 900 network (gsm)The GSM 900 frequency band is 2*25 MHz wide and includes 124

pairs of carrier frequencies, numbered [1 to 124], which are 200 kHzapart:

Uplink direction (MS–to–BTS) = 890 to 915 MHz

f1 = 890 + 0.2xN MHz where N = [1 to 124]

Downlink direction (BTS–to–MS) = 935 to 960 MHz

f2 = f1 + 45 MHz

GSM 850 networkThe GSM 850 frequency band is 2*25 MHz wide and includes 124pairs of carrier frequencies, numbered [1 to 124], which are 200 kHzapart:


f1 = 824.2 + 0.2x N MHz where N = [1 to 124]


f2 = f1 + 45 MHz

EXTENDED GSM network (extended gsm)The extended GSM frequency band is 2*35 MHz wide and includes174 pairs of carrier frequencies, numbered [0 to 124] and [975 to1023], which are 200 kHz apart:


f1 = 880.2 + 0.2x(N – 975) MHz where N = [975 to 1023]f1 = 890 + 0.2xN MHz where N = [0 to 124]


f2 = f1 + 45 MHz

GSM–R network (R gsm)The GSM–R frequency band is 2*39 MHz wide and includes 194 pairsof carrier frequencies, numbered [0 to 124] and [955 to 1023], whichare 200 kHz apart:


f1 = 876.2 + 0.2x(N – 955) MHz where N = [955 to 1023]f1 = 890 + 0.2xN MHz where N = [0 to 124


f2 = f1 + 45 MHz

GSM 1800 network (dcs1800)




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The GSM 1800 frequency band is 2*75 MHz wide and includes 374pairs of carrier frequencies, numbered [512 to 885], which are 200kHz apart:


f1 = 1710k2 + 0.2x(N – 512) MHz where N = [512 to 885] Downlink direction (BTS–to–MS) = 1805 to 1880 MHz

f2 = f1 + 95 MHz

GSM 1900 network (pcs1900)The GSM 1900 frequency band is 2*60 MHz wide and includes 299pairs of carrier frequencies, numbered [512 to 810], which are 200kHz apart:


f1 = 1850.2 + 0.2x(N – 512) MHz where N = [512 to 810]


f2 = f1 + 80 MHz

GSM 900 – GSM 1800 network (gsmdcs)The primary band is GSM 900The secondary band is GSM 1800

GSM 1800 – GSM 900 network (dcsgsm)The primary band is GSM 1800The secondary band is GSM 900

GSM 850 – GSM 1900 network (gsmdcs)The primary band is GSM 850The secondary band is GSM 1900

GSM 1900 – GSM 850 network (dcsgsm)The primary band is GSM 1900The secondary band is GSM 850

Remark: The frequency bands defined hereabove are the definition of theETSI.


Eng. Rules:

As P-GSM range is included in E-GSM one, the following table givesfor each current cell standard indicator, the type (main or other) ofneighbouring cells according to their standard indicator:

standard indicator Adjc (neighbouring cell)

PGSM E GSM GSM 1800

GSM 900 main other other

E GSM main main otherstandardIndicator

(current cell)GSM 1800 other other main

If one of a cell ARFCN is in [975;1023] & [0] range, this monobandEGSM (RGSM or EGSM) cell does not support monoband PGSM MSnor dualband PGSM/DCS1800 MS.If a EGSM cell has a BCCH in PGSM band, a PGSM mobile will listento it and may be handed over in that cell on a TCH in the E band. Inthat case, the mobile will send a handover failure.

Sys-infos management:




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According to recommendations, only « main » frequencies can bepresent in the SI2 and SI2bis (resp. 5 and 5bis).Following table gives the standard indicator of the neighbouring cellsthat can be included in the different sys_info messages.(extended gsm is noted EGSM in the table).

SYS_INFO

SI2 / SI5 SI2 bis / SI5 bis SI2 ter / SI5 ter

GSM 900 GSM GSM if neededE GSM + GSM1800 (1)

E GSMGSM + EGSM

GSM + E GSM ifneeded

GSM 1800standardIndicator

(current cell)

GSM 1800 GSM 1800GSM 1800 ifneeded

GSM + E GSM

Note (1): In that case, the number of frequencies in the frequency listis limited due to their large range.

=> Thus, due to the range of frequencies in EGSM + GSM 1800bands, and the fact that only 1 message (ter) can contain suchneighbours info (if StandardIndicator = GSM), it is stronglyrecommended to set the standard indicator of PGSM cells containingEGSM neighbours to extended gsm (2 messages to encode EGSMneighbours).




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5.28. DTX PARAMETERS

cellDtxDownLink Class 3 V7

Description: Whether the use of discontinuous transmission in BTS–to–MSdirection is allowed in a cell


Object: bts




Used in: Downlink DTX

Eng. Rules: DTXDownLink is particularly interesting in case of low interferednetworks with fractional reuse patterns for frequency plan. In this

case, it is recommended to uses a reactive configuration with a shortdelay between HO decision (runHandover=1) and with short averagewindows (Hreqt = 1, HreqAve = 4). Ho margins can also be lowered.

CAUTION! Using this feature may create a more sensitivity to bad values (fading,frequencies collision). Activation of DTXDownlink when DTX isalready used leads to a diminution in the precision of themeasurement on the cell, on quality and on level.

dtxMode Class 3 V7

Description: MS control of the discontinuous transmission mechanism in a cell

Discontinuous transmission is designed to lessen MS battery

consumption and diminish interference by breaking off thetransmission when no data or speech are being transmitted.

Value range: [FRmsmayuseDTX / HRmsshallnotuseDTX, FRmsshalluseDTX /HRmsshallnotuseDTX, FRmsmayuseDTX / HrmsmayuseDTX,FRmsshallnotuseDTX / HRmsshallnotuseDTX, FRmsshalluseDTX /HrmsshalluseDTX, FRmsshallnotuseDTX / HRmsshalluseDTX]

Object: bts

Default value: msMayUseDtx


Rec. value: msShallUseDtx

Used in: Uplink DTX Eng. Rules:

CAUTION! When AMR is activated that parameter should be set toFRmsshalluseDTX / HRmsshalluseDTX

See also chapter Impact of DTX on Averaging




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5.29. MISCELLANEOUS

Data14_4OnNoHoppingTs Class 3 V12

Description: Whether data 14.4 kbit/s transmission rate is allowed at bts level onthe non hopping TSs


Object: bts



Rec. value: TBD

Used in:

Eng. Rules:

data mode 14.4 kbit/s Class 2 V12

Description: Whether data 14.4 kbit/s transmission rate is allowed


Object: transcoderBoard


Type: DP

Rec. value: TBD

Used in:

Eng. Rules:

data non transparent mode Class 3 V12

Description: Set of transmission rates used for data non transparent modetransmission of the Radio interface and Abis interface.

Value range: [9.6 / 14.4] (kbit/s)

Object: bts

Default value: 9.6 kbit/s

Type: DP

Rec. value: TBD

Used in:

Eng. Rules:

data non transparent mode Class 3 V12

Description: Set of transmission rates used for data non transparent modetransmission of the Radio interface and Abis interface.

Value range: [9.6 / 14.4] (kbit/s)


Default value: 9.6 kbit/s

Type: DP

Rec. value: TBD

Used in:

Eng. Rules:




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data transparent mode Class 3 V12

Description: Set of transmission rates used for data transparent mode transmission

of the Radio interface and Abis interface.Value range: [“1.2/0.075” / 0.6 / 1.2 / 2.4 / 4.8 / 9.6 / 14.4] (kbit/s)

Object: bts

Default value:

Type: DP

Rec. value: TBD

Used in:

Eng. Rules:

data transparent mode Class 3 V12

Description: Set of transmission rates used for data transparent mode transmissionof the Radio interface and Abis interface.

Value range: [“1.2/0.075” / 0.6 / 1.2 / 2.4 / 4.8 / 9.6 / 14.4] (kbit/s)


Default value:

Type: DP

Rec. value: TBD

Used in:

Eng. Rules:

measurementProcAlgorithm Class 2 V12

Description: Whether the new L1M interface is used

Value range: [L1MV1, L1MV2]

L1MV1: the older L1M is used

L1MV2: the newer L1M is used

Object: bts


Rec. value: L1MV2


Direct TCH Allocation and Handover Algorithms

Eng. Rules: L1MV2 is not supported on DCU2.

It is not recommended to set L1MV2 on a DCU2/DCU4 BTS mixedconfiguration since the enhancements offered will be available only onpart of the site so with a call processing not homogeneous on thewhole communications.Major benefits are:

ability to support advanced capacity and coverage features such

as “Automated cell tiering”

capture process more reactive

less handover failure (better updating of eligible cells)




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diversity = “enabled”, provided diversity antenna(s) have been fitted tothe BTS.

diversity = “disabled” otherwise

2/ In and after v17.0 :diversity = “enhancedDiversity”, for eDRX and Radio Module family,provided diversity antenna(s) have been fitted to the BTS.

diversity = “disabled” in other cases.




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5.31. PCM ERROR CORRECTION PARAMETERS

Note : this feature is no longer supported as of V17.

enhancedTRAUFrameIndication V12

Description: before V17 : Whether the BTS uses the Enhanced TRAU Frame(ETF) for TCU

After V17 : This parameter is no longer useful in V17 as the featurePCM Error Correction is no longer supported

Value range: [notAvailable / available / active]

Object: bsc

Default value: n/a

Type: DI, Optimization

Rec. value: n/a

Used in: PCM Error Correction

Eng. Rules: The PCM Error Correction is no longer supported as of BSS V17release. This parameter is no longer useful and the OMC-R V17automatically forces its value to “notAvailable”.

pcmErrorCorrection Class 2 V12

Description: Before V17 : whether the bts uses the new ETF (Enhanced TRAUFrame) frame (set to “1”) or the ETSI “Rec 08.60” frame (set to “0”).

After V17 : This parameter is no longer useful in V17 as the featurePCM Error Correction is no longer supported.


Object: bts

Default value: n/a


Rec. value: n/a

Used in: PCM Error Correction

Eng. Rules: The PCM Error Correction is no longer supported as of BSS V17release. This parameter is no longer useful and the OMC-R V17automatically forces its value to 0.




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5.32. CELL TIERING PARAMETERS

enhCellTieringConfiguration Class 3 V14

Description: This attribute allows to configure the cell tiering algorithm at BTS level

This parameter is composed of the following five parameters:

hoMarginTiering

nbLargeReuseDataChannels

numberOfPcwiSamples

pwciHreqave

selfTuningObs



hoMarginTiering Class 3 V14

Description: Hysteresis between the uCirDLH and lCirDLH tiering thresholds. Usedto avoid ping-pong handovers (expressed in dB)



Default value: 4 dB


Rec. value: 4dB (to be optimized with the HO cell tiering monitoring)

Used in: Automatic cell tiering

Eng. Rules:

interferenceType Class 3 V14

Description: It is used for identifying the type of interference created by a neighborcell. The possible values are not applicable (no interference), adjacentinterference or cochannel interference.

Value range: [notApplicable / adjacent / coChannel]


Default value: notApplicable


Rec. value: This parameter should be set according to frequency planstrategy.


Eng. Rules:




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nbLargeReuseDataChannels Class 3 V14

Description: Mean number of logical channels belonging to the large frequency

reuse pattern and used at the same time for data communicationsValue range: [-16 to +16]


Default value: 0


Rec. value: To be determined according to configuration (see below)


Eng. Rules: This parameter gives the mean number of radio TS in the large reusepattern (BCCH) used for data communications (and consequently notavailable for tiering).

nbLargeReuseDataChannels = number of timeslots dedicated GPRS

+ average number of timslots for 14.4 if the parameter data 14.4OnNoHoppingTs is set to 1.This last value can be obtained through the counters 1705/2 and1707/2.

numberOfPwciSamples Class 3 V14

Description: Minimum number of PwCI samples required to reach a reliabledistribution (representative of the real distribution in the whole cell) *1000



Default value: 20


Rec. value: 20. However, it is a deal between PWCI distribution refresh timeand accurancy (see below).


Eng. Rules: It gives the minimum number of PWCI samples required to reach areliable distribution of PWCI that will be representative of the realdistribution in the whole cell x 1000.

The number of samples before a PWCI distribution is undertaken is :1000 x numberOfPwciSamples.

For example, in a cell bearing 29 TCHs and loaded at 75%, at eachmoment, 0.75x29=21.75 TCHs are occupied. Then, every 480 mswe’ll have 21.75 samples available and every second(1000*21.75)/480=45.3 samples. If we set numberOfPwciSamples at20, a PWCI distribution will be computed when 20000 samples will beavailable, wich means that a PWCI distribution will be computed every20000/45.3 = 441.5 seconds ( almost every 7 minutes and a half).




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pwciHreqave Class 3 V12

Description: Averaging window size for PwCI. It defines the number of

measurement reports for a PWCI arithmetic averaging.Value range: [0 to 16]


Default value: 8


Rec. value: 8


Eng. Rules: In a given cell, each communication in the cell reports itsmeasurements every 480 ms which allows computing the PWCI.When 20000 samples are gathered in the cell, a distribution of all thePWCI is computed and, lCirDLH and uCirDLH are determined for the

cell.In order to take a tiering decision, a PWCI is averaged over apwciHreqAve window, for each communication and compared tolCirDLH and uCirDLH obtained from the previous distribution, to lead(or not) to a handover decision.

selfTuningObs Class 3 V12

Description: BTS mode of the sending the PwCI distribution on the Abis interface.This allows a closer monitoring of the cell tiering feature behavioronce activated.

Value range: [pwCi distribution not sent,pwCi distribution sent after gathering,one pwCi distribution sent per hour]


Default value: pwCi distribution not sent


Rec. value: Other than “pwCi distribution not sent” when fine tuning thefeature, with close monitoring needed.


Eng. Rules: The possible values are pwCi distribution not sent (PWCI distributionis gathered but not sent onto the Abis interface), pwCi distribution sent

after gathering (the distribution is sent each time a new tieringthreshold is computed for a maximum of 10 cells) or one pwCidistribution sent per hour (the distribution is sent when a new tieringthreshold is computed but no more than one message every hour fora maximum of 40 cells).

Remark: PWCI distribution may be gathered and sent onto the Abis interfaceindependantly of tiering activation.




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5.33. ENCODING PARAMETERS

speechMode Class 3 V12

Description: List of the speech algorithms associated with channel use modes inthe cell

The “full rate” value refers to the standard algorithm. The “enhancedfull rate” value only applies when all the TCUs linked to the BSC areequipped with TCB2 boards.

Value range: list of [algoid] where algoid id: full rate, enhanced, full rate, AMR fullrate, AMR half rate

Object: bts

Default value: [full rate, enhanced full rate]

Type: DP

Rec. value: [full rate, enhanced full rate]Used in: AMR - Adaptative Multi Rate FR/HR

Eng. Rules:

CAUTION! When AMR is activated, SpeechMode must be set to full rate,enhanced full rate, AMR full rate, AMR half rate

speechMode Class 3 V12

Description: List of the speech algorithms associated with channel use modes onthe A interface. The “full rate” value refers to the standard algorithm.The “enhanced full rate” value only applies when all the TCUs linked

to the BSC are equipped with TCB2 boards.Value range: list of [algoid] where algoid id: full rate, enhanced, full rate, AMR full

rate, AMR half rate


Default value: [full rate, enhanced full rate]

Type: DP

Rec. value: [full rate, enhanced full rate]

Used in: AMR - Adaptative Multi Rate FR/HR

Eng. Rules:

CAUTION! When AMR is activated, SpeechMode must be set to full rate,enhanced full rate, AMR full rate, AMR half rate




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5.34. SMS-CELL BROADCAST PARAMETERS

smsCB Class 3 V12

Description: Whether broadcasting of short messages in unacknowledged mode isauthorized in a cell.

Value range: [used / unused]

Object: bts

Default value: used

Type: DP

Rec. value:

Used in: SMS-Cell Broadcast

Eng. Rules: Configuration of logical channels and broadcast of short messagesare managed by two separate OMC-R functions.

When a short message broadcast is started, the presence of a CBCHin the channelType of a channel object is dependent on a concernedbts object.However, the SMS-CB function are not aware of changes made tothat attribute.Consequently, withdrawing a CBCH from the configuration will stopany short message broadcast in the concerned cell without th SMS-CB function knowing.




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5.35. PROTECTION AGAINST INTRACELL HO PING-PONGPARAMETERS

capacityTimeRejection Class 3 V14

Description: Rejection time of a capacity intracell handover after an intracellhandover

Value range: [0 to 120 s.]


Default value: 0 s.

Type: DP

Rec. value: [15 to 30 s.]

Used in: Protection against Intracell HO Ping-Pong

Handover mechanisms (AMR)

Eng. Rules:

Remark: Applies to a BSC 3000 architecture only.

CAUTION! When AMR is activated that parameter should be set to 40 s

minTimeQualityIntraCellHO Class 3 V14

Description: Rejection time of a quality intracell handover after an intracellhandover

Value range: [0 to 120 s.]


Default value: 0 s.

Type: DP

Rec. value: [0 to 10 s.]

Used in: Protection against Intracell HO Ping-Pong


Eng. Rules:

Remark: Applies to a BSC 3000 architecture only.

Note: That parameter can be named qualityTimeRejection in the literature.

CAUTION! When AMR is activated that parameter should be set to 5 s




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5.36. AUTOMATIC HANDOVER ADAPTATION PARAMETERS

selfAdaptActivation Class 3 V12

Description: Use for activate the Automatic Handover adaptation


Object: bts


Type: DP

Rec. value: enabled

Used in: Automatic handover adaptation

Eng. Rules:

servingfactorOffset Class 3 V12

Description: This attribute defines the offset linked to the serving cell, used todecrease the HO margin, in some specific cases

Value range: [-63 to 63]


Default value: - 2

Type: DP

Rec. value: 0


Eng. Rules:




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neighDisfavorOffset Class 3 V12

Description: This attribute modifies the offset linked to the neighbouring cell, used

to increase the HO marging, in some specific casesValue range: [-63 to 63]


Default value: 2

Type: DP

Rec. value: 2


Eng. Rules:

Note: That parameter can be named offsetNeighbouringCell at the MMI.

rxQualAveBeg Class 3 V12

Description: This attribute defines the number of quality measurement results usedby the power control mechanism, in short averaging algorithm



Default value: 2

Type: DP

Rec. value: same as RxlevHreqAveBeg


Fast Power Control at TCH assignment (Pc_3)

Eng. Rules:




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5.37. GSM TO UMTS HANDOVER PARAMETERS

cId Class 3 V17

Description: Cell identity of the UMTS neighbouring cell for handover

Value range: 0..65535

Object: adjacentCellUTRAN

Default value: 0

Type: DP

Rec. value: n/a

Used in: GSM to UMTS handover (v17)

Eng. Rules: N/A

compressedModeUTRAN Class 3 V17

Description: flag to indicate whether compressed mode UTRAN is supported ornot. This flag is used by the network to indicate to mobiles whether touse a compressed version of the INTER RAT HANDOVER INFOmessage (UE to UTRAN message).

Value range: enabled/disabled

Object: bts


Type: DP



Eng. Rules: The UTRAN_CLASSMARK_CHANGE message sent by UE to theBSS takes about 2 or 3 radio frames. However, when supported bythe UTRAN network, it is possible to reduce the size of this messagethanks to the compression of UE radio access capabilities andpredefined configuration IE. This option is indicated inIMMEDIATE_ASSIGNMENT message sent to the UE (IA rest octetsfields). For that purpose, the parameter compressedModeUTRANindicates whether compression of UE information elements is

supported.

diversityUTRAN Class 3 V17

Description: flag indicating whether there is diversity in the neighbouring UTRANcell

Value range: no diversity/diversity


Default value: no diversity

Type: DPRec. value: see Eng. rules




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Eng. Rules: Please refer to diversity

earlyClassmarkSendingUTRAN Class 3 V17Description: flag indicating whether UTRAN classmark change message shall be

sent with Early Classmark Sending

Value range: disabled/enabled

Object: bts


Type: DP

Rec. value: enabled


Eng. Rules: earlyClassmarkSendingUTRAN shall be set to “enabled” before

handover 2G to 3G feature is activated.fDDARFCN Class 3 V17

Description: fDD channel number of the UTRAN neighbouring cell



Default value: N/A

Type: DP

Rec. value: N/A


Eng. Rules: N/A

gsmToUMTSServiceHo Class 3 V17

Description: This parameter serves to disable 2G-3G handover at BSC level or toindicate the preference (2G versus 3G cells) to be applied forhandovers

Value range: “should”/”should not”/”shall not”/”gsm to UMTS HO disabled”

Object: bsc

Default value: “gsm to UMTS HO disabled”

Type: DPRec. value: “should”


Eng. Rules: See GSM to UMTS handover (v17) section. This parameter is usefulin only 2 cases :

Case n°1 : the “service handover” field in HANDOVER REQUEST and ASSIGNMENT REQUEST is missing.

Case n°2 : the network operator wants to disable the 2G to 3Ghandover on the BSC, regardless of the presence, and/or the value, ofthe “service handover” field.




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hoMarginUTRAN Class 3 V17

Description: Handover margin for PBGT handover to a UMTS cell

Value range: -63 dB to 63 dB, in 1dB steps

Object: adjacentCellUTRANDefault value: 63 dB

Type: DP

Rec. value: - 6


Eng. Rules: If the operator wants to unload GSM traffic:

UMTS RSCP is lower than GSM Rxlev where a quite a high value isrequired for a good quality. This margin controls the probability toperform a handover.

Note that a the quality of UTRAN neighboring is ensured by thefDDreportingThreshold and fDDreportingThreshold2 parameter

hoMarginAMRUTRAN Class 3 V17

Description: Handover margin for intercell quality handovers to UMTS, for AMRcalls




Type: DP



Eng. Rules: TBD

hoMarginRxLevUTRAN Class 3 V17

Description: handover margin for signal strength handover to UMTS




Type: DP



Eng. Rules: TBD




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hoMarginRxQualUTRAN Class 3 V17

Description: handover margin to be used for signal quality handover to UMTS




Type: DP



Eng. Rules: TBD

hoMarginDistUTRAN Class 3 V17

Description: handover margin for handover to UMTS on distance criterion




Type: DP



Eng. Rules: TBD

hoMarginTrafficOffsetUTRAN Class 3 V17

Description: offset to be subtracted to the homarginUTRAN to allow handover fortraffic reason when the current cell is congested

Value range: 0 dB to 63 dB, in 1dB steps



Type: DP



Eng. Rules: TBD




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hoPingpongCombinationUTRAN Class 3 V17

Description: list of pair of causes indicating the causes of ping-pong handovers in

the overlapping areas. Each pair is structured as follows : (incomingHO cause, outgoing HO cause). Incoming HO cause indicates theessential handover cause which leads to enter the neighbour cell.outgoing HO cause indicates the non-essential handover cause whichleads to leave the neigbour cell.

Value range: list of pairs of causes (GSM to UMTS HO, UMTS to GSM HO): traffic,powerbudget, directed retry, Rxlev, Rxqual, distance, O&M (forcedHO), all, allpowerbudget.


Default value: (rxqual, pbgt)

Type: DP

Rec. value: (all, pbgt)Used in: GSM to UMTS handover (v17)

Eng. Rules:

hoPingpongTimeRejectionUTRAN Class 3 V17

Description: time that must elapse before attempting another handover towards anUTRAN cell. Refer to HOPingpongCombinationUTRAN attribute forthe combinations of HO causes for which this timer applies. To avoidping-pong handovers this new timer is started after a successful

handover. Up to the expiry of this timer, any HANDOVERINDICATION message received from the BTS is ignored by the BSC.

Value range: : 0...60 (0 means immediately).



Type: DP



Eng. Rules:

hoRejectionTimeOverloadUTRAN Class 3 V17

Description: time that must elapse before attempting another handover towards acongested UTRAN cell

Value range: 0..60 (60 means “immediately”)

Object: bsc


Type: DP



Eng. Rules:




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locationAreaCodeUTRAN Class 3 V17

Description: Location area code of the UMTS neighbouring cell



Default value: N/A

Type: DP

Rec. value: N/A


Eng. Rules: N/A

mobileCountryCodeUTRAN Class 3 V17

Description: Mobile Country Code (MCC) of the UTRAN neighbouring cellValue range: 000…999 (string)


Default value: N/A

Type: DP

Rec. value: N/A


Eng. Rules: N/A

mobileNetworkCodeUTRAN Class 3 V17

Description: Mobile Network Code (MNC) of the UTRAN neighbouring cell

Value range: 000…999 (string)


Default value: N/A

Type: DP

Rec. value: N/A


Eng. Rules: N/A

offsetPriorityUTRAN Class 3 V17

Description: priority offset applied by the BSC when selecting the candidate cell forthe handover process

Value range: 1..5


Default value: 1

Type: DP

Rec. value: 1


Eng. Rules:




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rNCId Class 3 V17

Description: identity of the UTRAN neighbouring cell’s RNC



Default value: N/A

Type: DP

Rec. value: N/A


Eng. Rules: N/A

rxLevDLPbgtUTRAN Class 3 V17

Description: downlink signal strength threshold above which handovers to UTRANfor cause power budget are inhibited

Value range: <-110 dBm, -110<x<-109, … to >-48 dBm


Default value: >-48

Type: DP

Rec. value: see Eng. Rule


Eng. Rules: This parameter has to be managed carefully because it can prevent

all the UTRAN handover for power budget when set to less than -110.

Moreover, the setting of this parameter has to be done with the help of

some radio measurement campaigns.

This parameter shall be disabled by setting the value to more

than –48 (dBm).

rxLevMinCellUTRAN Class 3 V17

Description: minimum signal strength level that the MS must measure on an UMTSneighbour cell to be able to be granted a handover to this UMTSneighbour cell

Value range: <-110 dBm, -110<x<-109, … to >-48 dBm


Default value: >-48

Type: DP

Rec. value: see Eng. Rule


Eng. Rules: The value of rxLevMinCellUTRAN must be greater than the value ofminimumCpichRscpValueForHO UTRAN parameter.




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scramblingCode Class 3 V17

Description: scrambling code of the UTRAN neighbouring cell

Value range: 0..511


Default value: N/A

Type: DP

Rec. value: N/A


Eng. Rules: N/A

t3121 Class 3 V17

Description: t3121 has the same use as t3103 in the GSM inter-BSC handoverprocedure. It sets the value before countdown of T3121 timer definedin the GSM specification .

T3121 starts when the BSC sends an INTER SYSTEM TO UTRANHANDOVER message to the mobile. T3121 stops when the mobilehas correctly seized the UTRAN channel. The purpose of this timer isfor the BSC to keep the old channels long enough for the mobile to beable to return to the old channels if necessary. On expiry of T3121(indicating the mobile is lost), the BSC may release the channels.

Value range: 2..255 seconds

Object: bts


Type: DP



Eng. Rules: T3121 purpose is very similar to T3103 one. However,INTERSYSTEM TO UTRAN HANDOVER COMMAND message fromBSS to Mobile is much larger than the HANDOVER COMMANDmessage so it takes about one second more to send the inter systemmessage to the MS. An additional safety margin should therefore be

considered for LAPDm repetitions.




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5.38. AMR - ADAPTATIVE MULTI RATE FR/HR PARAMETERS

BTS OBJECT

amrUlFrAdaptationSet Class 3 V15

Description: Define the lines of parameter used for the adaptation mechanism.

It sets the C/I thresholds when AMR speech codecs are used on a FRchannel in UL.when AMR speech codecs are used.

Value range: [0 to3]

Object: bts

Default value: 0

Type: DP

Rec. value: 3Used in: Codec mode adaptation

Eng. Rules:

0: typical radio condition

1: optimistic radio condition

2: pessimistic radio condition

3: personalize with the BSC data configuration table

The recommanded value of 0 offers a good compromise between HRpenetration and radio environment.For optimization of the table amrUlFrAdaptationSet should be turn to 3(refer to AMR Activation Guideline PE/BSS/APP/11438 in Reference

Documents)See also chapter AMR Engineering Studies.

amrUlHrAdaptationSet Class 3 V15




Object: bts

Default value: 0

Type: DPRec. value: 3

Used in: Codec mode adaptation

Eng. Rules:





The recommanded value of 0 offers a good compromise between HRpenetration and radio environment.For optimization of the table amrUlHrAdaptationSetshould be turn to 3

(refer to AMR Activation Guideline PE/BSS/APP/11438 in ReferenceDocuments)See also chapter AMR Engineering Studies.




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amrDlFrAdaptationSet Class 3 V15




Object: bts

Default value: 0

Type: DP

Rec. value: 3


Eng. Rules:





The recommanded value of 0 offers a good compromise between HRpenetration and radio environment.For optimization of the table amrDlFrAdaptationSetshould be turn to 3(refer to AMR Activation Guideline PE/BSS/APP/11438 in ReferenceDocuments)See also chapter AMR Engineering Studies.

amrDlHrAdaptationSet Class 3 V15




Object: bts

Default value: 0

Type: DP

Rec. value: 3


Eng. Rules:





The recommanded value of 0 offers a good compromise between HRpenetration and radio environment.For optimization of the table amrDlHrAdaptationSetshould be turn to 3(refer to AMR Activation Guideline PE/BSS/APP/11438 in ReferenceDocuments)See also chapter AMR Engineering Studies.




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filteredTrafficCoefficient Class 3 V15

Description: Filter coefficient taken into account in the cell load evaluation.

Value range: [0..1] step 0.001


Type: DP

Rec. value: 0.5

Used in: AMR based on traffic

Eng. Rules: The parameter shoud be set to 1 to reach V15.1 behaviour (HR callsallocated on RxLev criterion only)

fullHRCellLoadEnd Class 3 V18

Description: This attribute defines the threshold that triggers the ending of

congestion period of AMR MaximizationValue range: [0 to 100]

Object: bts

Default value: 100

Type: DP

Rec. value: 60

Used in: Channel allocation

Eng. Rules: This value should be tuned according to the operator strategy. But incase of activation of AboT the engineering rules related tointerworking between AMR maximization and AboT shall be followed.

fullHRCellLoadStart Class 3 V18

Description: This attribute defines the threshold that triggers the beginning ofcongestion period of AMR Maximization.


Object: bts

Default value: 100

Type: DP

Rec. value: 80


Eng. Rules: This value should be tuned according to the operator strategy. But incase of activation of AboT the engineering rules related tointerworking between AMR maximization and AboT shall be followed.




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sharedPDTCHratio Class 3 V18

Description: percentage of shared PDTCH TS (configured and available) taken intoaccount in the Filtered_Erlang


Object: bts

Default value: 0

Type: DP

Rec. value: 60


Eng. Rules: This parameter have to be tuned according to the PDTCH configuredon the cell and the MinGprsTS parameter in case of 4 PDTCH andMinGprsTS egal to 1 sharedPDTCHratio =75%

hrCellLoadEnd Class 3 V14

Description: This attribute is used to trigger the end of AMR HR allocation in thecell.


Object: bts

Default value: 0

Type: DP

Rec. value: 40


Eng. Rules: The parameter should be set to 0 to reach V15.1 behaviour (HR callsallocated on RxLev criterion only).

This value should be tuned according to the operator strategy and thenumber of TCH (preemptable PDTCH are not taken into account).

60 is a good compromise but it can be increased for cells with morethan 12 TCH.

hrCellLoadStart Class 3 V14

Description: This attribute is used to trigger the beginning of AMR HR allocation inthe cell.


Object: bts

Default value: 100

Type: DP

Rec. value: 0 for AMR FR only, different from 0 to trigger the HR allocation inthe cell.

60 for AMR based on Traffic

Used in: Channel allocation Eng. Rules: This parameter shall be different from “0” to use Half Rate allocation.

The parameter should be set to 1 to reach V15.1 behaviour (HRcalls allocated on RxLev criterion only)




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This value should be tuned according to the operator strategy and thenumber of TCH (preemptable PDTCH are not taken into account).

80 is a good compromise but it can be increased for cells with morethan 12 TCH.

TRANSCODER OBJECT

coderPoolConfiguration Class 2 V12

Description: This attribute indicates enumerated speech coding algorithmssupported by the TCU.

List of algoid [minimumCalls, powerUplink, powerDownlink]

Value range: Algoid: fullRateCoder, enhancedFullRateCoder,amrFullHalfRateCoder, ctmEnhancedFullRateCoder

MinimumCall: 0 to 65535

PowerUL: -15 to +15PowerDL: -15 to +15

Object: Transcoder

Default value: fullRateCoder, minimumCall = 1, pwrUL = 0, pwrDL = 0

enhancedFullRateCoder, minimumCalls = 1, pwrUL = 0, pwrDL = 0amrFullHalfRateCoder, minimumCalls = 1, pwrUL = 0, pwrDL = 0ctmEnhancedFullRateCoder, minimumCalls = 1, pwrUL = 0, pwrDL =0

Type: DP


Used in: Channel allocation (AMR)

Cellular Telephone Text Modem (TTY)

Eng. Rules: Used for the AMR, TTY activation at the TCU level (downlink anduplink amplification level and use to define the minimum of AMRcommunications on the TCU level).

Each coded has to be present only if is is activated by the operator,FR is mandatory.

During normal operation, it dynamically reallocates the resourcesbetween the TRMs to meet traffic demand. For the EFR and FRcodecs, the archipelago capacity is 72, i.e. 216 circuits per TRM. Forthe AMR codec, the archipelago capacity is 60, i.e.180 circuits per

TRM. For the EFR+TTY codec, the archipelago capacity is 48, i.e. 144circuits per TRM.The customer can set for each enabled vocoder type (FR, EFR, AMR)a warrantied minimum number of communications. This field is calledminimumCalls and is used for the initial distribution.The TCU assigns CODEC to each available archipelago in an round-robin manner until the TCU satisfies the minimumCalls condition foreach enabled CODEC. Remaining archipelagoes are configured inorder to achieve as close as possible the CODEC ratios given byminimumCalls parameters.Let nbMinimumCalls = sum of minimumCalls of each enable CODEC.The ratio to achieve for a given CODEC is computed as follows:CODEC_rate = (minimumCalls (for this CODEC) / nbMinimumCalls).

Examples:




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For E1 network with 20% FR, 40% EFR and 40% AMR setting couldbe:

FullRateCoder, minimumCalls = 4, powerUL = 0, powerDL = 0

EnhancedFullRateCoder, minimumCalls = 8, powerUL = 0,

powerDL = 0 amrFullHalfRateCoder, minimumCalls = 8, powerUL = 0,

powerDL = 0

Remark: Whatever is the repartition between the codecs, the two parameterspowerUL and powerDL should always be set to “0“.

For T1 network, no TTY CODEC is available at the MMI. So whentheTCU receives TRM related config messages indicating for eachCODEC(FR, EFR and AMR) their minimumCalls, the equivalentEFR+TTYCODEC is enabled with a minimumCalls set to 1 by default.

CAUTION! For any TCUe3 upgrade from V14/V15 to release V16.0, TTY must beexplicitly set at MMI on G3Trans object via thecoderPoolConfiguration field.




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TRANSCEIVER OBJECT

frAMRPriority Class 2 V14

Description: defines TDMA allocation priority for AMR FR calls.


Object: Transceiver

Default value: 0

Type: DP

Rec. value: 1 for BCCH TDMA

0 for hopping TDMA

Used in: Channel allocation (AMR)

Eng. Rules: BCCH and non-hopping TDMA should be set to low priority, i.e. 1,while hopping TDMA should be set to high priority, i.e. 0.

Priority 0 is given to a high priority TDMA,Priority 1 is given to a low priority TDMA,Priority 2 disables this service on the TDMA.See also chapter Isolated Areas in AMR Monitoring.

CAUTION! Priority 2 is not recommended as it could introduce an AMRcongestion on the cell due to a barring of access to some TDMAs for AMR calls. However, that setting could be interesting in some specificcases.

hrAMRPriority Class 2 V14

Description: defines TDMA allocation priority for AMR HR calls.


Object: Transceiver

Default value: 0

Type: DP

Rec. value: 1 for BCCH TDMA

0 for hopping TDMA


Eng. Rules: BCCH and non-hopping TDMA should be set to low priority, i.e. 1,

while hopping TDMA should be set to high priority, i.e. 0Priority 0 is given to a high priority TDMA,Priority 1 is given to a low priority TDMA,Priority 2 disables this service on the TDMA.See also chapter Isolated Areas in AMR Monitoring.

CAUTION! Priority 2 is not recommended as it could introduce an AMRcongestion on the cell due to a barring of access to some TDMAs for AMR calls. However, that setting could be interesting in some specificcases.




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POWER CONTROL OBJECT

Since the introduction of the ML0, there is a treshold preventing from doing Power Controlbelow a defined level when using AMR power control (refer to the amrReserved2 parameter).

The two parameters lRxLevDLP and lRxlevULP setting that threshold are defined in chapter

Power Control Parameters.

hrPowerControlTargetMode Class 3 V14

Description: AMR codec target to define the Uplink power control threshold for HR AMR calls

Value range: [4k75, 5k9, 6k7, 7k4]

Object: power controlDefault value: 7k4

Type: DP

Rec. value: 7k4

Used in: Power Control (AMR)

Eng. Rules: Power has to be decreased when call quality is very good andincreased when the quality could be better.

Even if 7k4 AMR HR is set, which corresponds to the mostconstraining Power control value, AMR Power control has shown tobe more aggressive than EFR Legacy L1m. If cell radio conditions arevery good, optimization to 6k7 HR target could be justified.Power control has to be triggered before handover for quality reason. AMRHRIntercellCodecModeThreshold<hrPowerControlTargetMode

frPowerControlTargetMode Class 3 V14

Description: AMR codec target to define the Uplink power control threshold for FR AMR calls

Value range: [4k75, 5k9, 6k7, 10k2, 12k2]

Object: power control

Default value: 12k2

Type: DP

Rec. value: 12k2



Even if 12k2 AMR HR is set, which corresponds to the mostconstraining Power control value, AMR Power control has shown tobe more aggressive than EFR Legacy L1m. If cell radio conditions arevery good, optimization to 10k2 FR target could be justified.Power control has to be triggered before handover for quality reason. AMRFRIntercellCodecModeThreshold<frPowerControlTargetMode




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hrPowerControlTargetModeDl Class 3 V16

Description: AMR codec target to define the downlink power control threshold for

HR AMR callsValue range: [4k75, 5k9, 6k7, 7k4]


Default value: 7k4

Type: DP

Rec. value: 7k4



Even if 7k4 AMR HR is set, which corresponds to the mostconstraining Power control value, AMR Power control has shown to

be more aggressive than EFR Legacy L1m. If cell radio conditions arevery good, optimization to 6k7 HR target could be justified.Power control has to be triggered before handover for quality reason. AMRHRIntercellCodecModeThreshold<hrPowerControlTargetModeDl

frPowerControlTargetModeDl Class 3 V16

Description: AMR codec target to define the downlink power control threshold forFR AMR calls



Default value: 12k2

Type: DP

Rec. value: 12k2



Even if 12k2 AMR HR is set, which corresponds to the mostconstraining Power control value, AMR Power control has shown tobe more aggressive than EFR Legacy L1m. If cell radio conditions arevery good, optimization to 10k2 FR target could be justified.Power control has to be triggered before handover for quality reason.

AMRFRIntercellCodecModeThreshold<frPowerControlTargetModeDl




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HANDOVER OBJECT

amrDirectAllocRxLevUL Class 3 V14

Description: Uplink RxLev threshold for direct AMR TCH allocation in a normal cellor in the large zone of a bizone cell (in conjunction withamrDirectAllocRxlevDL).



Default value: - 80 dBm



Used in: Handover mechanisms (AMR)


Eng. Rules: Direct HR allocation enables to avoid some unnecessary handoversfrom FR to HR channels. To define the value of those parameters it isnecessary to study the distribution of RxLev for the codec modedefined as the target for the HR to FR intra cell HO to avoid aimmediate come back on a FR channel after a direct HR allocation.The uplink parameter may be set considering a thresholdcorresponding to 90% of C/I values higher than 16 dB (proposedvalue, depends on the network quality). Furthermore, it has to bechecked that the RxLev value is more restrictive than the threshold togo back to the large zone to avoid an immediate comeback on thelarge zone.

See also chapter Half Rate Penetration Analysis.

amrDirectAllocRxLevDL Class 3 V14

Description: Downlink RxLev threshold for direct AMR TCH allocation in a normalcell or in the large zone of a bizone cell (in conjunction withamrDirectAllocRxlevUL).








Eng. Rules: Direct HR allocation enables to avoid some unnecessary handoversfrom FR to HR channels. To define the value of those parameters it isnecessary to study the distribution of RxLev for the codec modedefined as the target for the HR to FR intra cell HO to avoid aimmediate come back on a FR channel after a direct HR allocation.The uplink parameter may be set considering a thresholdcorresponding to 90% of C/I values higher than 16 dB (proposedvalue, depends on the network quality). Furthermore, it has to bechecked that the RxLev value is more restrictive than the threshold togo back to the large zone to avoid an immediate comeback on thelarge zone.




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See also chapter Half Rate Penetration Analysis.

amrDirectAllocIntRxLevUL Class 3 V14

Description: UplinkRxLev threshold for directAMR TCH allocation in the inner zoneof a bizone cell (in conjunction with amrDirectAllocIntRxlevDL).








Eng. Rules: see Engineering Rules of amrDirectAllocRxLevUL.

amrDirectAllocIntRxLevDL Class 3 V14

Description: Downlink RxLev threshold for directAMR TCH allocation in the innerzone of a bizone cell (in conjunction with amrDirectAllocIntRxlevUL).






Used in: Handover mechanisms (AMR) Direct TCH Allocation

Eng. Rules: see Engineering Rules of amrDirectAllocRxLevUL.

Furthermore, it has to be checked that the RxLev value is morerestrictive than the threshold to go back to the large zone to avoid animmediate comeback on the large zone.amrDirecAllocIntRxLevDL≥ concentAlgoIntRxLev

amrFRIntercellCodecMThresh Class 3 V14

Description: Target codec mode to trigger an intercell AMR quality handover.

Value range: [4k75, 5k9, 6k7, 10k2, 12k2]Object: handoverControl

Default value: 6k7


Rec. value: 10k2


Eng. Rules: The target codec mode has to be more restrictive than the one forintracell handover otherwise intracell handover will not be possiblemost of the time.

amrFRIntercellCodecMThresh<amrFRIntracellCodecMThresh .On the other hand, the codec mode threshold for intercell handover

has to be smaller than the target codec for power control.amrFRIntercellCodecMThresh< frPowerControlTargetMode




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This parameter is directly linked to AMR adaptation set and the C/Ithreshold. Intercell codec target, which directly applies on a C/I target,has to be aligned to C/I relation with RxQual. CPT could be used.C/I associated to HO intercell codec target should be between 7dBand 14 dB depending on radio environment

amrFRIntracellCodecMThresh Class 3 V14

Description: Target codec mode to trigger an intracell quality handover FR to FR



Default value: 4k75


Rec. value: 4k75 (AMR intracell deactivation value)


Eng. Rules: The target codec mode has to be less restrictive than the one forintercell handover otherwise intracell handover will not be possiblemost of the time.

amrFRIntercellCodecMThresh<amrFRIntracellCodecMThresh

amrHRIntercellCodecMThresh Class 3 V14

Description: Target codec mode to trigger an intercell quality handover from a HRchannel.



Default value: 5k9


Rec. value: 5k9


Eng. Rules: The target codec mode has to be more restrictive than the one forintracell handover otherwise intracell handover will not be possiblemost of the time.

amrHRIntercellCodecMThresh< amrHRtoFRIntracellCodecMThresh .On the other hand, the codec mode threshold for intercell handoverhas to be smaller than the target codecs for power control.amrHRIntercellCodecMThresh< hrPowerControlTargetMode.

amrHRtoFRIntracellCodecMThresh Class 3 V14

Description: Target codec mode to trigger an AMR intracell quality handover from AMR HR to FR



Default value: 6k7


Rec. value: 6k7





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Eng. Rules: The target codec mode has to be less restrictive than the one forintercell handover otherwise intracell handover will not be possiblemost of the time. In case same intercell and intracell codec target ischosen, intercell has the priority.

amrHRIntercellCodecMThresh <AMRHRtoFRIntracellCodecMThresh

If the operator’s strategy is to increase capacity versus quality, lowvalues for AMRHRtoFRIntracellCodecModeThreshold can be chosento delay a come back on a FR channel.Change of AMR adaptation set could also be used for HR penetrationincrease (see chapter Half Rate Maximization Analysis)

amriRxLevDLH Class 3 V14

Description: Minimum downlink level to receive to trigger an intracell handover FRto FR

Value range: [less than -110, -110 to -109, ..., -49 to -48, more than -48] dBm

Object: handoverControlDefault value: - 75 dBm




Eng. Rules: Since AMR coding is better than standard coding, the threshold forintracell AMR handover must be more restrictive than the one forstandard calls: amriRxLevDLH>rxLevDLIH.

amriRxLevULH Class 3 V14

Description: Minimum uplink level to receive to trigger an intracell handover FR toFR







Eng. Rules: Since AMR coding is better than standard coding, the threshold for

intracell AMR handover must be more restrictive than the one forstandard calls: amriRxLevULH>rxLevULIH.




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amrReserved1 Class 3 V16

Description: Allows the activation of RATSCCH procedure for AMR FR calls


0: RATSCCH procedure enabled (default value)

1: RATSCCH procedure disabled - initial Full Rate ACS if optimistic

therefore; ACS is [12.2k, 10.2k, 6.7k, and 5.9k]

2: RATSCCH procedure disabled - initial Full Rate ACS if pessimistic

therefore; ACS is [10.2k, 6.7k, 5.9k and 4.75]


Default value: 0

Type: DP

Rec. value: 0

Used in: AMR Legacy L1M

Eng. Rules: Before v15.1.1, in case of poor uplink radio conditions, the BTS issometimes unable to detect RATSCCH acknowledgements frommobiles. This triggers a mismatch between the AMR Codec Set usedby the mobile and the one used by the BTS. Then the BTS (or MS)cannot correctly decode the codec used by the MS (or BTS). Thissequence leads to a mute call until the next RATSCCH procedure iscorrectly executed.

A workaround for this problem of mute call consists in settingamrReserved1 to value “1” which means “RATSCCH disabled andinitial ACS optimistic” : only codec 5k9, 6k7, 10k2 and 12k2 will beused. The only drawback of the workaround is that this parameter

setting prevents the usage of 4,75 AMR FR codec, useful in case ofvery degraded radio conditions.

In v16, an improvement of the L1M has been implemented whichconsists in the BTS repeating the RATSCCH command until itreceives an acknowledgment from the mobile.

In v17, a further improvement has been implemented. It consists inimproving the robustness of the detection of the acknowledgementmessage received from the mobile : this increases the probability ofcorrectly decoding this message when it is first received.

Thanks to these 2 improvements, amrReserved1 should be set to "0"in V16 and V17.

Warning: pessimistic Codec Set 10,2 / 6,7 / 5,9 /4,75 (amRreserved1= 2) must not be chosen because it would inhibit capacity HO i.e.handover from AMR FR to AMR HR (as 12.2 cannot be used).

amrReserved2 Class 3 V12

Description: Legacy L1m procedures (Power control and Handover) or AMR L1mmechanisms (based on (n,p) voting algorithm and codec target) canbe chosen



Default value: 0

Type: DP





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Used in: AMR Legacy L1M

Eng. Rules:

amrReserved2

AMR alarm handovers

based on

AMR PowerControl

algorithm based on

0 CMR/CMC [(n,p) voting] CMR/CMC

1 RxQual CMR/CMC

2 CMR/CMC [(n,p) voting] RxQual

3 RxQual RxQual

CAUTION! A mix between AMR L1m for Power Control and Legacy L1m for AMRalarm HO is recommended at this stage (amrReserved2 = 1); however AMR activation with full AMR algorithms on HO management andPower Control has shown good performances.

nCapacityFRRequestedCodec Class 3 V14

Description: Number of 12k2 codec mode requested to trigger a capacity handover(FR to HR)



Default value: 44


Rec. value: set to 100% of pRequestedCodec, i.e. 48


Eng. Rules: The recommended value was chosen in order to increase capacity inreal good conditions: 100% of the requested codecs should be 12k2meaning the radio conditions are really good. If the operator’s strategyis to increase capacity vs. quality, low value fornCapacityFRRequestedCodec can be chosen.

Higher nCapacityFRRequestedCodec assures a better HR radioconditions and reduce probability intraHO ping pong.See also chapter Half Rate Settings.

nFRRequestedCodec Class 3 V14

Description: Minimum number of codecModeRequest out of pRequestedCodec inthe (n,p) voting mechanism to trigger an AMR HO while in FR mode.



Default value: 24




Eng. Rules:




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nHRRequestedCodec Class 3 V14

Description: Minimum number of codecModeRequest out of pRequestedCodec in

the (n,p) voting mechanism to trigger an AMR HO while in HR mode.Value range: [0 to 196]


Default value: 34




Eng. Rules:

pRequestedCodec Class 3 V14

Description: Number of codec mode requests to consider in the (n,p) votingdecisions.

Value range: [12 to 192] (step of 12)


Default value: 48


Rec. value: 48


Eng. Rules: A similar reactivity between AMR and non-AMR calls should bereached. The recommended value corresponds to the same qualityaveraging window as for standard calls in urban environment. Fieldexperimentation should give further information as for the value ofpRequestedCodec.




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ADJACENTCELLHANDOVER

hoMarginAMR Class 3 V14

Description: HO margin taken into account in an intercell quality handover for AMRcalls in order to manage the eligible cell list.


Object: AdjacentCellHandover

Default value: - 2


Rec. value: same as hoMarginRxQual


Handovers screening

Eng. Rules: In case of AMR L1mis activated (cf. amrReserved2) Handover cause AMR quality: case where access to another cell should beencouraged, provided target cell field strength is not much lower thanthe current one. If bad quality remains, there is a risk of returnhandover but there is nothing much to be done.

Depending on radio environment:

Interfered environment:

It is better to have a low C/I threshold for Quality HO (chosen via AMRadaptation set or intercell HO codec target) and have homarginAMR =hoMarginRxQual

Coverage limited environment:

It is better to have a high C/I threshold for Quality HO (chosen via AMR adaptation set or intercell HO codec target) and have hoMargin= hoMarginRxQual + 2

REPEATED DOWNLINK FACCH

enableRepeatedFacchFr Class 2 V16

Description: Enable/ disable the Repeated FACCH feature on AMR FR calls

Value range: Disable / FR 4.75 / FR 5.9 and lower / FR 6.7 and lower

Object: btsDefault value: Disable


Rec. value: FR 6.7 and lower


Eng. Rules:




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enableRepeatedFacchHr Class 2 V16

Description: Enable/ disable the Repeated FACCH feature on AMR HR calls

Value range: Disable / FR 4.75 / FR 5.9 and lower / FR 6.7 and lower

Object: bts

Default value: Disable




Eng. Rules:

TX POWER OFFSET FOR SIGNALLING CHANNELS

facchPowerOffset Class 2 V16

Description: Power offset to be applied on FACCH signalling

Value range: [0 to 10] dB (with 2 dB step)

Object: bts

Default value: 0


Rec. value: 6

Used in: This parameter is used to tune the power offset to be applied onFACCH re-transmission, specific FACCH messages (for firsttransmission) as well as RR and REJect frames on FACCHcorresponding to an uplink re-transmission (F bit set to 1) and UAframes corresponding to an uplink re-transmission of SABM or DISCframes (F bit set to 1).

Eng. Rules:

sacchPowerOffset Class 2 V16

Description: Power offset to be applied on SACCH signalling

Value range: [0 to 6] dB (with 2 dB step)

Object: bts

Default value: 2


Rec. value: 6

Used in: This parameter is used to tune the power offset to be applied onselected SACCH frames transmission

Eng. Rules:




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sacchPowerOffsetSelection Class 2 V16

Description: CODEC selection for applying a power offset on SACCH

Value range: NULL / FR 4.75 kbps / FR 5.9 and lower / FR 6.7 and lower

Object: bts

Default value: NULL



Used in:

Eng. Rules:

AMR-HR CHANNEL ON PREEMPTED PDTCH

gprsPreemptionForHR Class 3 V17

Description: Activation of PDTCH pre-emption for HR channel


Object: bsc



Rec. value: enabled

Used in: pDTCH Preemption by AMR FR or HR calls (V17) Eng. Rules: “AMR based on traffic” thresholds may need to be retuned if the

PDTCH preemption for HR channels is enabled.




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5.39. WPS - WIRELESS PRIORITY SERVICES PARAMETERS

wPSManagement Class 3 V15

Description: WPS feature is enabled or disabled

Value range: [disabled ; enabled ]

Object: bsc


Type: DP, System

Rec. value: enabled for WPS use

Used in: WPS - Wireless Priority Service

Eng. Rules: In order to enabled the new queuing management of WPS requeststhe wPSManagement flag has to be set to the value “enabled”

CAUTION! Queuing management of WPS requests can only be activated if thebscQueuingOption parameter is set to “allowed” (MSC driven) and theWPS priorities have been set properly

wPSQueueStepRotation Class 3 V15

Description: One out of the wPSQueueStepRotation value to first have anevaluation of the WPS queues in the radio resource allocator.


Object: bts

Default value: 4

Type: DP, System

Rec. value: 4

Used in: WPS - Wireless Priority Service

Eng. Rules: If the operator choose to activate WPS queuing management on itsnetwork this parameter can ensure a minimum amount of non-WPScalls (with low priorities) that can access the network even if it is verycongested

With that parameter fixed to “4”, when a radio resource become freeand there are WPS or public call requests queued, the priority is given1 out of 4 times to a WPS call request and 3 out of 4 times to a publiccall. In that case WPS calls are favored in 25% of the time.

CAUTION! The operator can choose to enabled queuing uniquely on WPS calls,hence public calls are never queued and this parameter becomeobsolete.

The Algorithm for the traffic channel allocation applies at a cell level inthe BSC, and hence wPSQueueStepRotation is a cell parameter.




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5.40. NETWORK SYNCHRONIZATION PARAMETERS

btsSMSynchroMode Class 2 V15

Description: Type of site synchronization.

Activation of the Synchronisation feature (either site synchro eithernetwork synchro features). Its value defines also the synchronizationmode (burst or time)

Value range: [normal, master, slave, gprBurstSync, gpsTimeSync,masterGpsBurstSync, masterGpsTimeSync]


Default value: normal


Rec. value: normal

Used in: Network Synchronization Eng. Rules:

tnOffset Class 2 V15

Description: Its value allows to specify and control TN difference between BTS incase of network synchronisation by GPS

Value range: [0..7]


Default value: 0


Rec. value: 0

Used in: Network Synchronization

Eng. Rules:

fnOffset Class 2 V15

Description: Its value allows to specify and control FN difference between BTS incase of network synchronisation by GPS

Value range: [0..84863]


Default value: 0


Rec. value: N/A


Eng. Rules:




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dARPPh1Priority Class 2 V15

Description: Its value allows specifying the priority of SAIC mobiles on the TDMA.

Value range: [high priority, low priority]

Object: transceiver

Default value: high priority


Rec. value: high priority


Eng. Rules: Actually, for radio resource allocation only SDCCH requests are notdifferentiated depending if the mobile requesting is SAIC capable ornot.

masterBtsSmId Class 2 V15

Description: Gives the identity of the master BTS if the BTSSMSynchroMode isslave and remains empty if the BTS is master or normal

Value range: Master BTS id or empty


Default value: Empty


Rec. value: Depends on context


Eng. Rules:

baseColourCode Class 2 V7

Description: Base station Color Code assigned to a serving cell. It is broadcast onthe cell SCH and is used to distinguish cells that share the sameBCCH frequency.

The (BCC, NCC) pair forms the cell BSIC.The information is broadcast on the cell SCH.Several BCCs may be assigned to a same BTS. Hence, differentcodes can be allotted to cells that may have overlapping areas(adjacent cells).The Base Station Identity Code (BSIC) is a 6–bit code: bits 6-5-4 =NCC (PLMN color code), bits 3-2-1 = BCC (Base station color code). At cell level, the NCC bits can be used to increase BCC colorpossibilities when the NCC is not needed.

The BCC value is determining the TSC (training sequence code) ofthe cell.


Object: bts

Default value: N/A




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Rec. value: N/A


Eng. Rules: Several BCCs may be assigned to cells of a same site. Hence,

different codes can be allotted to cells that may have overlappingareas (adjacent cells). See also chapter Set Up Principles of aNeighboring List and a BCC Plan

5.41. NETWORK MODE OF OPERATION PARAMETERS

gprsNetworkModeOperation Class 3 V15

Description: Flag to choose the network mode of operation.

Value Range: [0 - 2] ; 0 = NMO II , 1 = NMO I , 2 = NMO 3 (value forbidden) .

Object: bts.

Default value: 0.

Rec. value: 1.

Used in: Network Mode of Operation I support in BSS

Eng. rules: NMO 1 must be activated or deactivated at RA level: the setting mustbe consistent in all cells of a RA.

NMO1 activation is recommended when GPRS is activated on all cellsof the network: NMO1 should not be activated on a LA where somecells do not affer GPRS service.

As combined procedures are performed on PDTCH with NMO1(combined attach/detach and combined LA/RA update), it is stronglyrecommended to guaranty the continuity of GPRS service by settingminNbrGprsTs > 0.

The feature must be activated first at Core Network level and then atBSS level.

The bscDataConfig must be modified to take the value ofgprsNetworkModeOperation into account. (see [R36] for details)




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5.42. BSS CS PAGING COORDINATION PARAMETER

bssPagingCoordination Class 3 V17

Description: Activation parameter of BSS CS Paging Coordination feature

Value range: 0: disable BSS CS paging coordination/ 1: enable BSS CS pagingcoordination

Object: bts

Default value: disable BSS CS paging coordination



Used in: BSS CS Paging Coordination Eng. Rules: On (legacy) PCUSP board, the processing load is expected to

consume a significant proportion of the available processingcapability. In that case, the impact of the feature activation should bemonitored. See section Performance of BSS CS Paging coordination

5.43. NOVEL ADAPTIVE RECEIVER PARAMETER

adaptiveReceiver Class 2 V17Description: Activation parameter of the novel adaptive receiver


Object: transceiver



Rec. value: enabled

Used in: Novel Adaptive Receiver

Eng. Rules: 1/ For cells operating under very specific radio conditions, namelyhard Hilly Terrain profiles, the Novel Adaptive Receiver structure may

possibly cause a slight performance loss compared with the initialprocessing. Therefore, it is recommended to disable the adaptivereceiver for these cells.

2/ If Rx diversity is used, best receiver performance is achieved byactivating both the Joint diversity and the Novel Adaptive Receiverfeatures

3/ Novel Adaptive Receiver does not interwork with the Extended Cellfeature. Therefore, for extended cells, the Novel Adaptive Receivermust be deactivated.




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5.44. A5/3 ENCRYPTION ALGORITHM PARAMETERS

cypherModeReject Class 1 V8

Description: Whether the CIPHER MODE REJECT messages are used (Phase IIcompliance).

Value range: true/false



Type: DP

Rec. value: true

Used in: A5/3 Encryption algorithm (V17) Eng. Rules: This parameter must be set to true for the ciphering procedures to

operate correctly between the BSS and the NSS

encrypAlgoAssComp Class 1 V8

Description: Whether the "Chosen encryption algorithm" element is used in the ASSIGN COMPLETE messages (Phase II compliance).




Type: DP

Rec. value: true

Used in: A5/3 Encryption algorithm (V17)

Eng. Rules: This parameter must be set to true for the ciphering procedures tooperate correctly between the BSS and the NSS

encrypAlgoCiphModComp Class 1 V8

Description: Whether the "Chosen encryption algorithm" element is used in theCIPHER MODE COMPLETE messages (Phase II compliance).




Type: DP

Rec. value: true






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encrypAlgoHoPerf Class 1 V8

Description: Whether the "Chosen encryption algorithm" element is used in theHANDOVER PERFORMED messages (Phase II compliance).




Type: DP

Rec. value: true



encrypAlgoHoReq Class 1 V8

Description: Whether the "Chosen encryption algorithm" element is used in theHANDOVER REQUEST ACKNOWLEDGE messages (Phase IIcompliance).




Type: DP

Rec. value: true



encryptionAlgorSupported Class 3 V8

Description: Type of ciphering capability supported by the BTSs of a BSS. Whenno ciphering capability is supported, users’ calls are not encrypted bythe BSS over the air interface.

Value range: [none, gsmEncryptionV1, gsmEncryptionV3FallbackNoEncryption,gsmEncryptionV3FallbackV1]

Object: bsc

Default value: none

Type: DP



Eng. Rules: The setting of this parameter depends on the level of data integrityand security required by the network operator. A5/3 is more powerfulthan A5/1 but may slightly impact Call setup time and handover

duration.




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Notes: 1/This parameter’s class has been modified from class 0 to class 3 inv17.0.

2/This parameter’s range has been modified from [none /

gsmEncryptionV1 / gsmEncryptionV2] to [none, gsmEncryptionV1,gsmEncryptionV3FallbackNoEncryption,gsmEncryptionV3FallbackV1] in v17.0.

3/A5/2 must no longer be used in any network, as of December 2006.

layer3MsgCyphModeComp Class 1 V8

Description: Whether the "Layer 3 message" element is used in the CIPHERMODE COMPLETE messages (Phase II compliance).



Default value: falseType: DP

Rec. value: true



5.45. BTS SMART POWER MANAGEMENT PARAMETERS

smartPowerManagementConfig Class 3 V17

Description: Enable/disable the smart power management feature.

Value range: disabled/ enabled/enhanced



Type: DP

Rec. value: enhanced

see Eng. Rules

Used in: BTS Smart Power Management (V17) Eng. Rules: 1/ It is recommended to put combined BCCH and SDCCH/8 TS on the

same TDMA as BCCH.

2/ As a TRX supporting a PDTCH never switches its PA off, it isrecommended not to configure more PDTCH TS than necessary.




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smartPowerSwitchOffTimer Class 3 V17

Description: Sets the initial countdown value of the timer that must expire beforethe PA may be switched OFF.

Value range: 5 to 255 minutes in 1-minute steps


Default value: 5 minutes

Type: DP

Rec. value: 5 minutes

see Eng. Rules

Used in: BTS Smart Power Management (V17)

Eng. Rules: The smaller the switch-off timer :

• the more reactive the power management will be to theminute-by-minute changes to the call profile as the dayprogresses towards quieter moments

• the more power is likely to be saved as a result.

• but the more frequently the PA is likely to go through off/oncycles, especially at the transition from busy hour to quieterhours, thus possibly impacting its lifespan.




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5.46. ENHANCED VERY EARLY ASSIGNMENT PARAMETERS

EATrafficLoadEnd Class 3 V18

Description: Used to trigger the activation/deactivation of VEA allocation, accordingto Filtered_TCH_ratio.

Value range: 0...100 step 1

Object: bts

Default value: 100

Type: DP

Rec. value: 40

Used in: Enhanced very Early assignment Eng. Rules:

EATrafficLoadStart Class 3 V18

Description: Used to trigger the activation/deactivation of VEA allocation, accordingto Filtered_TCH_ratio.

Value range: 0...100 step 1

Object: bts

Default value: 100

Type: DP

Rec. value: 60

Used in: Enhanced very Early assignment

Eng. Rules:

VEASDCCHOverflowAllowed Class 3 V18

Description: Used to allow (or not) the SDCCH overflowing when EVEA isactivated.

Value range: Disabled (0) / Allowed(1)

Object: bts

Default value: 0Type: DP

Rec. value: 1

Used in: Enhanced very Early assignment

Eng. Rules:




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6. ENGINEERING ISSUES

6.1. GSM/GPRS TS SHARING: PRIORITY HANDLING ANDQUEUING

With GSM/GPRS TS sharing, the operator’s strategy can be of three main different kinds:

• Minimize the impact of GPRS introduction on GSM.

• Guarantee GPRS quality of service thus impacting on GSM if no resources

are added

• Find a trade-off impacting GSM as little as possible and guaranteeing GPRS

as much as possible.

The tuning of priority handling, queuing and also the use of the preemption mechanismdepends on the adopted strategy.

6.1.1 RESOURCES RESERVED FOR PRIORITY 0 ANDPREEMPTION

allocPriorityThreshold is a parameter used to reserve resources for priority 0 TCH allocation

requests. This reservation of resources decreases the capacity for incoming calls when

resources are reserved for handovers. Depending on the difference between

allocPriorityThreshold and the number of shared PDTCH, several phenomenon can happen.

IF allocPriorityThreshold ≥ shared PDTCH

THEN GPRS preemption mechanism is reserved for priority 0 TCH allocation requests

This behaviour is normal and comes from the definition of allocPriorityThreshold and the

allocation strategy that allocates in priority free TCH.

On the contrary:

IF allocPriorityThreshold ≤ Number of shared PDTCH

THEN the only free resources left for priority 0 TCH allocation request are shared

PDTCH.

• Reestablishment will not be enabled at those periods of time (no

reestablishment on shared PDTCH is allowed).

• A more frequent issue will come from GprsPreemption set to yes enabling the

PCU to NACK a preemption requested by the BSC. This phenomenon

decreases the efficiency of allocPriorityThreshold: reserved resources

considered free by the BSC might not be used to serve a TCH allocation

request when the PCU NACKs the preemption. This phenomenon will only

happen in case of heavy GPRS traffic at the same time as heavy GSM traffic.




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The table below proposes a setting of GSM/GPRS TS dynamic sharing with priority handling

with or without reestablishment (MinNbOfGprsTs is only indicative). With reestablishment, two

sets of values are sometimes proposed, one of them for less GPRS capacity.

Number of TRX allocPriorityThreshold minNbOfGprsTsNumber of shared

PDTCH

1 TRX with or without reestablishment 1 1 0

2 TRX with or without reestablishment 2 1 1

3 TRX without reestablishment 2 2 2

2 2 13 TRX with reestablishment

3 2 2

4 TRX without reestablishemnt 2 2 2

2 2 14TRX with reestablishment

3 2 2

6.1.2 GSM/GPRS TS SHARING AND QUEUING:

No queued allocation request can use the preemption mechanism to leave the queue. The

allocation request must wait until a TCH is free. Hence, a too high number of shared PDTCH

(without adding a TDMA) increases the time a queued request will stay in the queue.

A solution to decrease the length of the queue is to forbid intracell queuing (intraCellQueuing

set to disabled). The intracell handover request will be repeated later (increases the BSC

signaling load) if no resource is free but thanks to the repetition of the handover request if the

radio conditions are still bad, the shared PDTCH preemption will be allowed (not the case if

put in queue).For example on a 2 TDMA cell queuing can be done on 14 TCH TS, but in the case of a 2

TDMA cell with 3 shared PDTCH and minNbOfGprsTs = 0 the queuing can only be done on

11 TCH TS, so queued requests will leave the queue less quickly and one could see an

increase in the number of discarded requests.




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6.1.3 RESOURCES STRATEGY

MINIMIZE IMPACT OF GPRS INTRODUCTION ON GSM

• Gprspreemption is set to no

• MinNbGprsTS is set to 0

It means that all PDTCH configurated are shared by GSM and GPRS and thePCU is not

allowed to NACK the preemption requested by the BSC.Impact on queuing, impact on

preemption depending on allocPriorityThreshold value.

GUARANTEE GPRS QUALITY OF SERVICE

• GprsPreemption set to yes

• MinNumberGprsTs > 0

It means that some resources are always dedicated to GPRS and that the PCU can NACK a

pre-emption requested by the BSC.

Impact on queuing and preemption efficiency since the PCU can NACK the preemption

It might be interesting to activate HO traffic so as to enable a spatial repartition of traffic on

overlapping cells (with protection against HO ping pong): this spatial repartition of traffic will

save PDTCH channels for GPRS traffic and guarantee a constant availability of preemptable

PDTCH.

TRADE-OFF ON GSM AND GPRS

• GprsPreemption set to no

• minNumberGprsTs> 0

IMPACT ON QUEUING.

Minimum resources are guaranteed to GPRS and all the other resources can be used by GSM

calls if needed since the PCU can never NACK a preemption. It might be interesting to

activate HO traffic so as to enable a spatial repartition of traffic on overlapping cells (with

protection against HO ping pong): this spatial repartition of traffic will save PDTCH channelsfor GPRS traffic and guarantee a constant availability of preemptable PDTCH.




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6.2. MINIMUM TIME BETWEEN HANDOVER

Different cases of handovers are given, and for each, the parameter setting influence is

described.

6.2.1 MICRO-CELLULAR NETWORK

HANDOVER MICROCELL TO MICROCELL

Avoiding handover ping-pong is important but a mobile could cross a cell in 2 or 3 seconds. A

delay (bts Time Between HO configuration) should not be used in this case.

The parameter setting should be:

• timeBetweenHOConfiguration = true, because the feature may be important

for other cells in the BSS.

• bts Time Between HO configuration = minimal value, e.g. = rxLevHreqave *

rxLevHreqt * 0.48 sec

Actually, even in such configuration, the value of the delay depends on the speed of the

mobiles. If the speed is low and the mobile speed in the cell is homogeneous then the delay

can be significant and have an action on ping-pong handover. If the speed is non

homogeneous then the most “rapid-moving mobiles” must be considered for the value of the

delay, though ping-pong handovers could occur. The lower the most rapid moving mobiles’

speed, the more important the delay is”. Then bts Time Between HO configuration is a

function of the cell size and the mobile speed.

In such situation, the problem of field variation is solved:

• If the mobile speed is low then the delay will help to avoid a ping-pong

handover

• If the mobile speed is high, the averaging will not show all these variations.

HANDOVER MICROCELL TO MACROCELL

microCell means: its bts object cellType is set to microcell.macroCell means: in the microcell adjacentCellHandOver object, the cellType field

corresponding to this macrocell is set to “umbrella” whatever the value of its cellType field in

its bts object (normal cell, umbrella or microCell). In this way a microCell can be seen as an

umbrella for another microCell.

This kind of handover is only triggered on alarm cause. So, in this case the delay is not very

useful.

Let’s consider the following case:




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With a macroCell, the delay can be used for the microCell. A mobile that goes from microCell

A to macroCell B will perform a handover (on alarm cause). Then, it is worth setting a delay on

cell A to avoid a ping-pong handover (between A and C).

Therefore, this delay is beneficial for a mobile in cell C that turns into the street of cell A. The

same is true in opposite direction.

The only restriction is for a mobile coming from macro B and going to micro C. The delay has

a negative influence for the handover microA-microB. It is the same case as before.

The feature General Protection against HO ping-pong can solve this kind of problem. Forinstance, in this particular case, the parameter hoPingPongCombination should be set to

(alarm, capture) and hoPingPongTimeRejection should be set to the previous V9 value of bts

Time Between HO configuration.

HANDOVER MACROCELL TO MACROCELL

The timer is usefull for a cell intersection where there is much interference.

Let’s take as an example a handover with cause “quality” triggered from macroCell A towards

macroCell B. But just after this change of cell, a handover with cause “power budget” is

attempted. Using an appropriate delay, depending on the speed of the mobile, many ping-pong handovers may be avoided.

This is also achieved through the General Protection against HO PingPong feature (see

chapter General protection against HO ping-pong). In this particular case, the parameter

hoPingPongCombination should be set to (quality, PBGT) and hoPingPongTimeRejection

should be set to the previous V9 value of bts Time Between HO configuration. In order to

inhibit completely the ping-pong hoPingPongCombination should be set to (all, all).

macroCell B

microCell A

microCell C

macroCell B

microCell A

microCell C




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6.2.2 NON MICRO-CELLULAR NETWORK.

The solution is the use of the minimum time between handover. The value of the delay

depends on the distance between the interference point and the point where macroA and

MacroB have the same level. With the hypothesis that the following neighbor cell is far away,the value of the delay depends on the minimun speed of the mobile.

It is not really obvious to recommend a value because it is a question of interference point

position. So, before test and measurement results, the recommended value is the default

value: 16, that corresponds to 8 seconds.

There are two ways to determine the best value:

• system test: the counters show that ping-pong handovers exist. With a little

variation of the delay (bts Time Between HO configuration), it is possible to

see the influence (always with counters). So with only some steps of delay

variation the best value to avoid ping-pong handover and radio link failure canbe found.

• measurements: with mobile measurements, the point of interference and the

equivalence point can be found. Then the delay value can be deduced from

the distance between both points.

However the following “light constraints” are applied to the value of the delay:

• average time of a mobile in the cell (weighted if nedeed for each speed)

• bts Time Between HO configuration.

Those constraints could also be a way to find the best value of minimum time between

handover.




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6.3. DIRECTED RETRY HANDOVER BENEFIT

This paragraph provides theorical studies results of the benefit that Directed Retry can provide

in mono and multi-layers Networks.The Directed Retry is mainly a benefit in the case of smallcongestion zone in the network. In others cases the network is either under-dimensioned or

the queuing gives better results. Moreover, the HOTraffic feature must be favoured instead of

using Directed Retry.

6.3.1 BENEFIT OF FEATURE ON MONO-LAYER STRUCTURE

O HYPOTHESIS

• 12 macroCells with 3 TRX/cell

• Non-combined BCCH

• 22 TCH available for the 12 cells

• 9 cells with 41% use rate (i.e. 9 TCH/22) and 3 overloaded cells with 26

channels requested for 22 available (i.e. 24% of blocking rate)

• 25% of cell overlapping

WITHOUT DIRECTED RETRY

The carried capacity is:

• 9 cells * 9 TCH + 3 * 76% * 26= 140 Erlang

• the highest blocking rate is over 24%

Long duration

Large surface

Duration of

congestion

Directed Retry

CallNormal

situation

Network

under dimensioned

Long duration

Large surface

Duration of

congestion

Directed Retry

CallNormal

situation

Network

under dimensioned




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WITH DIRECTED RETRY

The added carried capacity is:

• 25% cell overlapping => 25% * (24% * 26 requests * 3) = 4,7 Erlang

• the highest blocking rate is over 18%

With Directed Retry and 25% overlapping: gain on traffic 3,3% on the whole set of 12 cells of

this example and gain on blocking rate.

6.3.2 BENEFIT OF FEATURE ON MULTI-LAYERS STRUCTURE

HYPOTHESIS

• blocking rate of 2% max on the macroCell• 3 TRX (22 TCH) with 9 TCH used / 22 (41% use rate)

• 1 TRX per μ -cell with not combined BCCH

• 10 requests for 6 TCH on the μ -cell (48% of blocking rate)

WITHOUT DIRECTED RETRY

Carried capacity of “n” μ-cell under 1 macroCell: = n μ-cell * 52% + 1 macro * 9 * 100%

For “n” μ-cell under 1 umbrella cell: number of carried Erlangs = 5,2n + 9

If n = 1, we have carried 14,2 Erlangs.

WITH DIRECTED RETRY

When the Macrocell begins to be full (the blocking rate will become low (from 2% to 3%)) then

no more calls are redirected from the µ-cell to the macro.

Capacity of microCell + macroCell: we aim to satisfy the 10 + 9 requests (i.e. 19 Erl needed):

n micro * X% * 10 + 1 macro * 9

The macro cell is able to carry: 14.9 Erlang

• 9 requests from the macroCell

• 5.9 requests from the μ-cells

Then, the macroCells keep: X% * ((n macroCell * 10) – 5.9)

WITH N = 1:

The Erlang law gives X = 87.6% (a blocking rate of 12.4%), the carried traffic is:

14.9 + 87.6% * (10-5.9) = 18.5 Erl

Gain 30% on ONE μ-cell and the highest blocking rate is over 12.4% (instead of 48%).




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WITH SEVERAL N:

microCells transfer their calls into one umbrella-cell, and with the hypothesis of our example,

the gain should be (en = enabled, dis = disabled):

As a consequence Gain(%) = f (number of µ-cells under one umbrella).

The best cells to implement directed retry are the cells that have potential problems due to a

lack of TCH resources. Directed Retry may solve the problem of load if the cell is the only one

to have this kind of problem in the close area. If the entire area is congested, almost no

improvement will be observed.

If queuing is enabled on the cell, the parameter setting of the queuing should lead to queues

of size 3 and a waiting timer of 6 seconds in the candidate cell.

Directed Retry can be also activated without queuing. See chapter Directed retry without

queuing activation for further informations.

The last value to set is the rxLev threshold used in the feature to choose a “good” neighborcell (distant mode). As the decision is taken on the basis of one measurement, a margin of a

few dBs needs to be taken to deal with multipath fading. Then, the advised value should be at

least rxLevMinCell + 3 dB.

Gain%=Erl carried DR(en)

Erl carried DR(dis)- 1 Gain%=

X(n) * (10n – 5,9) – (5,2n + 9)

5,2n + 9Gain%=

Erl carried DR(en)

Erl carried DR(dis)- 1 Gain%=

X(n) * (10n – 5,9) – (5,2n + 9)

5,2n + 9




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EXAMPLE OF POSSIBLE CONFIGURATIONS:

At BSC level:

• interBscDirectedRetry = allowed

• intraBscDirectedRetry = allowed

• modeModifyMandatory = used

• bscQueuingOption = forced

• timeBetweenHOConfiguration = true

• HOSecondBestCellConfiguration = 3

At Cell level (where directed retry is implemented):

• allocPriorityTimers = 0 0 6 0 0 0 0 0

• allocWaitThreshold = 0 0 3 0 0 0 0 0

• directedRetryModeUsed = bts

• interBscDirectedRetryFromCell = allowed

• intraBscDirectedRetryFromCell = allowed

At neighbor cell level:

• directedRetry = rxLevMinCell + 3 dB

• hoPingPongTimeRejection = 30 (= the previous V9 value of bts Time Between

HO configuration

• hoPingPongCombination = (DirectedRetry , all) or for instance (DirectedRetry,

PBGT)

At cell level for neighbor cells:

• bts Time Between HO configuration = 1 (V12 update, the parameter changes

its possible vallues)

• allocPriorityThreshold = 3




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6.4. CONCENTRIC CELLS

The concentric cell feature has been introduced from the BSS version V9.1. The main

principle is to define two zones in a cell: inner (or small) and outer (or large) zone. BCCH andsignaling channels use TMDAs of outer zone.

This feature enables the system to have two separate zones within the same cell using

different TDMAs and giving the operator flexibility to have separate frequency hopping

systems. Therefore, concentric cell zones give better spectral efficiency through mobility

management between zones and being able to increase inner zone frequency reuse.

For a good understanding of this feature, please refer to the chapter

Concentric/DualCoupling/DualBand Cell Handover , and the associated Functional Notes [R10] Concentric cell improvements (CM888/TF889) and [R11] FN for stepped coupling.

Expected Network Impacts:

• Radio Quality Improvement: C/I and RxQual improvement and an overall RF

and HO drops improvement

• Slight increase in intracell HO drops, inherent to concentric cell interzone

traffic management.

Outerzone

(large zone)Innerzone

(small zone)

BCCH and

signalling

channels

traffic

channels

Outerzone

(large zone)Innerzone

(small zone)

BCCH and

signalling

channels

traffic

channels




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6.4.1 CONCENTRIC CELL PARAMETER DEFINITION

As shown on the figure above, the definition of inner zone coverage depends mainly on

concentAlgoExtRxLev; concentAlgoIntRxLev and biZonePowerOffset+hysteresis parameters.

Main related parameters to the concentric cell feature are listed below:

Parameter Description

concentric cell enable the concentric cell feature on the cell (also used for dualband / dualcoupling)

concentAlgoExtRxLev level threshold used for TCH Direct Allocation in the inner zone or to trigger an interzone HO from theouter to the inner zone

concentAlgoExtRxLevUL * Uplink level threshold used for TCH Direct Allocation in the inner zone or to trigger an interzone HOfrom the outer to the inner zone

concentAlgoIntRxLev level threshold used to trigger an interzone HO from th inner to the outer zone

concentAlgoIntRxLevUL * Uplink level threshold used to trigger an interzone HO from th inner to the outer zone

biZonePowerOffset offset used to simulate the power difference between TDMAs of the inner and the outer zone (powerdifference either due to power emission, coupling losses or propagation losses)

zone Tx power max reduction set the power difference between the two zones of a concentric/dualaband/dualcoupling cell

concentAlgoExtMsRange distance threshold used for TCH Direct Allocation in the inner zone or to trigger an interzone HO fromthe outer to the inner zone (not used for dualband functionality)

concentAlgoIntMsRange distance threshold used to trigger an interzone HO from th inner to the outer zone

biZonePowerOffset(n) offset used to reflect the difference of propagation between the two zones of an adjacent cell in case ofhandover toward the inner zone

rxLevMinCell(n) minimum signal strength level received by MS for being granted access to a neighbor cell

*From V18 new parameters are added in order to secure uplink path during direct allocation

and interzone HO

CONCENTALGOEXTRXLEV

The concentAlgoExtRxLev value can be set depending on how TRXs capacity in the cell is

shared between the inner and outer zone. The following figure shows CPT cumulative

distribution of RxLev uplink and downlink of a cell before concentric cell activation.

concentAlgoExtRxLev may be deduced from the downlink RxLev distribution which representssamples of communications in function of the strength level.

concentAlgoIntRxLev(inner to outer

threshold)

concentAlgoExtRxLev(outer to inter threshold)

biZonePowerOffset

+ hysteresis Margin

concentAlgoIntRxLev(inner to outer

threshold)

concentAlgoExtRxLev(outer to inter threshold)

biZonePowerOffset

+ hysteresis Margin




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On the figure above we can see that only 10% of the traffic is handled with a level under -86dBm. So if the traffic size of inner zone (% of TS in the inner zone with regard to total number

of TS in the cell) is 90% of the outer zone, it means that 90% of downlink Rxlev sample may

be inside of inner zone, and 10% is outside. A downlink RxLev value L90, L75 or L50 should

then correpsond to 90%, 75% or 50% of traffic on the inner zone.

concentAlgoExtRxLev = LXX (use of the CPT tool)

BIZONEPOWEROFFSET (HANDOVERCONTROL OBJECT)

biZonePowerOffset is used to simulate the power offset between TDMAs of the inner and the

outer zone.

CONCENTRIC CELL CASE

In this case biZonePowerOffset simulates the power difference between the two zones

introduced by zone Tx power max reduction of the inner zone.

• zoneTxPowerMaxReduction(outer) = 0

• zoneTxPowerMaxReduction(inner) = 0, best value tested (see

chapter zone Tx power max reduction)

biZonePowerOffset = zone Tx power max reduction(inner)

DUALCOUPLING CELL CASE


introduced by coupling losses.

• zone Tx power max reduction(outer)=0

• zone Tx power max reduction(inner)=3 simulates the D/H2D

configuration

• zone Tx power max reduction(inner)=4 simulates the H2D/H4D

configuration

biZonePowerOffset = zone Tx power max reduction(inner)




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Note: DLU Attenuation should be NULL and replaced by zone Tx power max reduction as

explained in the parameter description: zone Tx power max reduction and concentric cell.

DUALBAND CELL CASE


introduced by propagation losses. It should then be set according to the band used on the cell.

biZonePowerOffset = +3 dB (dualband: main band= 850 or 900 MHz)

biZonePowerOffset = -3 dB (dualband: main band= 1800 or 1900 MHz)

CONCENTALGOINTRXLEV

To avoid ping-pong interzone HO, a hysterisis margin is recommended. The level threshold to

trigger an interzone HO from the inner to the outer zone could be calculated as follow:

concentAlgoIntRxLev = concentAlgoExtRxLev - Hysteresis Margin -

biZonePowerOffset

where Hysteresis Margin = 4 dB is recommended.

BIZONEPOWEROFFSET(N) (ADJACENTCELLHANDOVER OBJECT)

biZonePowerOffset(n) in adjacentCellHandover object reflects the difference of propagation

between the two zones of an adjacent cell in case of handover toward the inner zone. When

attempting an HO directly to the inner zone of an adjacent cell EXP2xx(n) = hoMarginxx(n) +

biZonePowerOffset (n) > 0 shall be respected. So in order to avoid HO in sequence afterincoming HO into inner zone, it’s necessary to respect the following relation:

biZonePowerOffset (n) = concentAlgoExtRxLev(n) - rxLevMinCell(n)

rxLevMinCell(n)

concentAlgo

ExtRxLev(n)

cellA cellB

rxLevMinCell(n)

concentAlgo

ExtRxLev(n)

cellA cellB




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6.4.2 CONCENTRIC CELL FIELD EXPERIENCE

RADIO QUALITY IMPROVEMENT

Inner zone isolation-capacity trade-off is found in concentric cell. The smaller the inner zone

coverage, the better inner zone isolation is found but less traffic, which takes profit of higher

inner zone fractional reuse pattern, is carried. Concentric cell success on improving KPI

performances is based on this balance.

On one hand reducing inner zone coverage:

• provides better isolation of inner zone interferences by keeping only the calls

with very good RxLev to enter the inner zone

• allows deploying a more constraining inner zone frequency plan (or a

consequent inner zone radio quality improvement) and reducing 3107 dropssince inter HO are done in better radio conditions.

On the other hand, one of the inherent risks of using this approach is to block on the outer

zone while resource availability remains on the inner zone. Even though inner zone blocking is

not customer perceived (calls can overflow onto the outer zone radios if available TCH

resources), a compromise exists between the traffic distribution between the zones, and the

improvement in KPI. Therefore, additional tuning of the concentAlgoExt/IntRxLev thresholds

may be necessary on certain sites to set an appropriate threshold for transitioning from and to

the inner zone.

INNER-OUTER ZONE CAPACITY TRADE-OFF

It is recommended having more than 1 TDMA on outer zone since it allows redundancy in

case BCCH TDMA is lost, and also because TDMAs carrying SDCCH channels must also be

on the outer zone. Furthemore, it is advised to have higher capacity in the outer than in the

inner zone, because it minimizes the probability that outer zone is blocked, which would cause

a capacity cell reduction even if inner zone TS are available.

60%-40% outer-inner capacity is recommended.

CONGESTION TARGET FOR HO TRAFFIC

Capacity is shared between inner and outer zone depending on TDMAs allocated in eachzone. Outer zone congestion targets should be updated to take into account reduction in terms

of TDMAs in outer zone. Inner zone is not considered for congestion since no congestion for

the user is found when all TS are occupied.

SDCCH DIMENSIONING

It should be noted that with Concentric Cell SDCCH channels cannot be configured in the

inner zone and all the SDCCH channels will have to be re-mapped to the outer zone radios.

All the sectors prior to implementation of Concentric Cell in the concerned BSCs must follow

Nortel’s recommended rule of spreading the SDCCH channels amongst different radios and

therefore had to be re-mapped carefully such that SDCCH congestion is not encountered.




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CONCENTRIC CELL PARAMETER TUNING

ZONE TX POWER MAX REDUCTION

This parameter is used to reduce the output power of the BTS on the inner zone TDMAs to

improve inner zone isolation. Simulations show it is preferred to keep the inner zone reduction

at 0 dB and rely on power control efficiency to reduce power level. Like this, power control is

always capable to power up to maximum power to save worst call who received punctual

interferences. Inner zone power reduction has not brought any significant KPI improvement

when it has been tested on field trials.

Simplified power control simulation results are shown on graph below. 250 meters of cell

radius in 1900MHz (150 meters for inner zone coverage which corresponds to 40% inner zone

capacity for a uniform traffic distribution) and perfect power control to attempt DL RxLev target

of -86 dBm are considered.

If BTS inner zone TDMA are not attenuated at all (0dB), 14,8 dBm mean BTS TX DL power

would be found while if 8 dB output power would be attenuated, mean BTS TX DL Power

would become 13,4 dBm. Therefore the impact on interference and isolation on innerzone is

very limited and it is preferred to leave power control the possibility to power up rather than

induce an external attenuation

CONCENTALGOEXT/INTRXLEV

It is recommended to set concentAlgoExtRxLev using CPT tool. DL RxLev number of samples

repartition found in CPT is a good indicator on how traffic load is spread around the cell.

concentAlgoExtRxLev threshold can be defined to match inner/outer zone capacity repartition.

It is recommended to define concentAlgoExtRxLev instead of concentAlgoIntRxLev throughCPT methodology. Like this, inner zone RxLev samples are slightly underestimated (signal

BTS Power and RxLev evolution depending on

BTSoffset parameter

0

5

10

15

20

25

30

35

40

45

50

0,00 0,05 0,10 0,15 0,20 0,25

Cell Range [km]

B T S P o

w e r [ d B m ]

-104,0

-102,0

-100,0

-98,0

-96,0

-94,0

-92,0

-90,0

-88,0

-86,0

-84,0

R x L e v [ d B m ]

BTSPower(Offsetpower0)

BTSPower(Offsetpower8dB)

InnerZone Coverage (40%)

RxLev(Offsetpower0)

RxLev(Offsetpower8dB)




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level from concentAlgoExtRxLev and concentAlgoIntRxLev could also be allocated in inner

zone) and a margin to pack the inner zone TDMAs is left.

concentAlgoExt/IntRxLev impact on inner/outer traffic load has not shown to be very sensible

to their value. Same mean values have been spread all over clusters in field trials and they

have required little tuning to avoid outer zone blocking and KPI improvements.

CONCENTALGOEXT/INTMSRANGE

concentAlgoExtMsRange and concentAlgoIntMsRange could be used to reinforce or to

complement inner and outer inter zone handovers using concentAlgoExt/IntRxLev.

The calculated distance between the MS and the BTS is based on timing advance (TA), which

has an accuracy of ± 3 bits (corresponding to more than 1,5 km), due to the shift of

synchronization of some MSs. Thus, this parameter is not very useful in urban areas where

the cell size is relatively small and due to the multipath effect, the MS to BS distance is not

very accurate. However this parameter could be used in rural areas or suburban areas.

BIZONEPOWEROFFSET IN DUALBAND CELLS

6 dB Rxlev DL level difference has been found between 900 MHz and 1800 MHz calls due to

propagation losses in field trials. When a call who is allocated in the outer zone (900MHz) is

inter handover to inner zone (1800MHz), 6 dB level loss is expected to be found due to

propagation loss.

Since biZonePowerOffset is taken into account in power budget handovers, there is a trade-off

between biZonePowerOffset value and number of power budgets of inner zone calls. Having a

biZonePowerOffset too big can reduce significantly power budget of inner cell provoking calls

to be dragged to inner zone cell edge because of overestimating own BCCH level of the

outerzone.

6 dB presents a good trade-off and it is the value recommended.

INTRACELL HANDOVER DROP SLIGHT INCREASE

On activation of concentric cell feature, interzone handovers get triggered based on signal

level within the same cell, increasing the probability of dropped calls. The key to successful

implementation of Concentric Cell is to reduce the other drop call components such as T3103

and RLT Drops.

HYSTERISIS MARGIN DEFINITION

The inner to outer Hysteresis Margin corresponds to the delta between concentAlgoIntRxLev

and concAlgoExtRxLev minus zone TX power maximum reduction. The delta should be

adequate so that the captured traffic in the inner zone (which is the key to spectral efficiency)

is not immediately allocated back to outer zone via a ping-pong handover. A big hysterisis

zone helps to contain the users in the inner zone and keeps this zone packed in order to avoid

losing capacity and interzone HO, therefore it reduces T3107 drops.




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L1M REACTIVITY

It is not recommended to increase L1m reactivity when concentric cell is used for HO

decisions since it can increase significantly interzone HO with the consequent increase on

T3107 drops. An average of 8 frames is recommended.

CONCENTRIC CELL IMPACT ON AMR HR PENETRATION

Interzone handover from inner to outer zone is considered as a quality handover. Therefore,

even though an AMR HR call was on going in the inner zone, after a quality inner to outer

interzone handover AMR FR is allocated in outer zone.

Depending on AMR FR to HR and HR to FR thresholds, this interzone handovers can cause

an increase of intracell HO from HR to FR (inner to outer zone) and immediately from FR to

HR (in the outer zone), reducing AMR HR penetration on the cell.




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6.5. IMPACT OF DTX ON AVERAGING

The RxLev_Full measured on a dedicated channel is the arithmetic mean of 104 received time

slots power, excepted in the case of DTX: then it is the arithmetic mean of only 12 receivedtime slots power.

A study was done to compare the difference (RxLev_Full - RxLev_Sub). It was based on

10800 measurements from a single network, characterized by a great proportion of microcells

and a high RxLev mean value.

The following array presents the results of this study. We considered the difference

(RxLev_Full - RxLev_Sub), without averaging (1 measurement), and then with averaging on 2,

3, 4 and 8 measurements.

number of values for averaging 1 2 3 4 8

mean value of RxLev_Full - RxLev_Sub (dB) - 0,15 - 0,15 - 0,15 - 0,15 - 0,15

standard deviation (dB) 2,12 1,48 1,19 1,03 0,72

The results show that, for an averaging on 4 measurements, the standard deviation is only 1

dB. This is insignificant enough to consider that we can run simulations, and analyze the

measurements with one of the two levels, if we don’t know which one is used.

Moreover, the measurement processing used for the neighbor cells is close to the process

used in the case of DTX: it is the arithmetic mean of about (104/N) received time slots power,

where N is the number of neighbor cells declared, between 1 and 32.

If 6 < N < 12, which is often the case, the two processes are quite comparable. 8 to 10 for

neighbor; standard deviation on RxLev_Sub can be extended to RxLev(i).

This means that the RxLev_NCell(i) measured on a neighbor cell, is close to the RxLev that

would be measured if it was the current cell.




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6.6. BEST NEIGHBOUR CELLS STABILITY

The parameter CellDeletionCount is used to keep a neighbor cell eligible, even if a few

measurements are lost.

A study was done with a measurement file of 2 hours, without handover. Each time one of the

6 best neighbor cells disappeared, the time before it re-appeared, called absent_time, was

calculated. 420 absent_times were found; that follow this distribution:

absent_time (s) % % cumulate

0,66 1,18 1,18

1,32 1,89 3,07

1,98 4,01 7,08

2,64 5,42 12,5

3,3 1,89 14,39

3,96 4,01 18,4

4,62 4,48 22,88

5,28 1,65 24,53

5,94 1,42 25,94

6 to 11 8,02 33,96

> 11 66,04 100

Note: absent_time values are multiples of 0,66 seconds.

For instance, for the recommended value 5 and according to these measurements, in 12,5

percent of the cases the neighbor cell concerned is accessible after 2,64 seconds, in 87,5

percent, it is still missing.




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6.7. TCH ALLOCATION GENERAL RULES

When no queuing is allowed, as no request can be treated by the BSC at the same time, there

are two kinds of TCH allocation requests:

• priority 0: the request is acknowledged if there is at least one free TCH

• priority > 0: the request is acknowledged if there is at least

allocPriorityThreshold + 1 free TCHs

If allocPriorityThreshold equals 0, all the requests are treated in the same manner.

If queuing is in OMC driven mode (run by the BSC), incoming handovers cannot be queued.

The highest priority must be given to incoming handovers.

The queuing plays a part when, there is not enough TCH resources. When traffic increases to

a blocking state, the queuing has no impact on the total ratio of TCH allocation success: the

more call attempts that are acknowledged, the more incoming handovers are refused.

The queuing is prefered when all TCH resources are busy during a short time; it cannot

replace a resource.

Please refer to chapter TCH Allocation Management.




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6.8. GENERAL RADIO FREQUENCY RULES

1) In dB, the path loss slope with distance, decreases as 1/D. This means that the received

signal variation, in dB/m, is greater at the close vicinity of the base station and decreases withthe distance. It depends directly on the propagation exponent.

2) We can assume stationnarity (during some seconds) of the median path loss in dB,

assumption is more and more valid since the MS is far from its antenna cell, close to the

handover area.

3) Shadowing is due to obstruction of the signal paths, created by obstacles. It is known that

these obstacles create log_normal variations of the received signal, ie the received power at a

distance, expressed in dBm, fluctuates as a gaussian random variables.

4) The shadowing “depth” is strongly linked to the position of the mobile as compared with the

dominant building, and as a consequence, that shadowing decorrelates when different

buildings are involved. With a building mean width d = 30m, shadowing can be considered

completely decorrelated.

5) The higher the mobile speed, the smaller the impact of the shadowing on the average

signal.

6) The higher the average window size is, the smaller the impact of the shadowing on the

average signal is.

7) The variance of the signal due to the Rayleigh fading, depends on the speed of the mobile

and of the frequency in use. About 30 to 50 wavelengths must be spanned to ”filter out” the

fading variations with a residual error less than 1 dB. If the number of samples is equal to N =

10 the mean matches the true local mean to within 2 dB at 90%.

8) Whatever the mobile speed, from a certain window size the increase of the size does not

modify the average Rayleigh standard deviation. From 8 to 16 samples, even at a very low

speed the gain is inferior than 0.5 dB.

9) The dispersion of two MRC combined Rayleigh is decreased by more than 1.5 dB for an

MRC order 2, compared to a single channel. It means that diversity reception can help

average out the fading faster than a single channel, i.e the local mean is tracked faster. If d >

20 l, an efficient 2 order space diversity has the same effect as multiplying the speed by 3 to 4.

10) .With Rayleigh fading, it is known that the mean in dB of samples in Watts is greater than

the mean in dB of samples in dBm. The limit is 2.5 dB, that means that the RXLEV tends to beartificially 2.5 dB higher for the uplink than for the downlink.

11) The RxLev_Full as measured on a dedicated channel is the arithmetic mean of 104

received time slots power, in the case of DTX, only 12 times.




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6.9. DIFFERENCE BETWEEN UPLINK AND DOWNLINK LEVELS

At the BTS, averages are performed from measurements made in Watts before . On the

contrary, some MS make measurements in dBm and then, perform their averages. In Rayleighenvironment, the first method of calculating can be up to 2.51 dB higher than the second

method.

This comes from the fact that in Rayleigh fading environment, the information goes through

several paths (at least two) between the BTS and the MS. At the antenna, according to the

phase of the signal, the different path can add up or not. This varies with time and it can vary

from complete cancellation (hole) or, on the contrary, perfect adding. This effect is called

multipath fading.

This effect implies that received levels follow a Gaussian law and its mean has an exponential

density. The evaluation of the bias between the mean of the decibels and the mean in

decibels is then:

10 .Log (e) ξ = 2.51 dB

This comes from the following expression that relates the mean of the natural logarithm of an

exponential random variable of mean one to the Euler constant (ξ):

∑ Ln (x) exp (- x) dx = ξ = 0,57721

The 10.Log (e) factor just accounts for the base 10 log.

In this normalised example:

• averaged mean of Watt samples converted in dB = 0 = BTS

calculation

• averaged mean of dB samples = 2.51 dB = MS calculation

So, the maximum difference between the two ways of calculating the average power is 2.51

dB. The uplink value will be the higher.

However, here, the hypothesis of the Rayleigh fading lead to deal with two paths, if there are

many paths, the value of the correction needs to be decreased.




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6.10. EFFECTS OF SMS-CELL BROADCAST USE ON“NOOFBLOCKSFORACCESSGRANT”

If the SMS-CB feature is activated, SMS-CB messages are carried on the CBCH, a subchannel of the SDCCH. The TDMA model mapping of the SDCCH becomes SDCCH-CBCH/8,

and the CBCH occurs from frame number 8 to frame number 11 of the SDCCH multiframe.

If noOfBlocksForAccessGrant = 0, then a paging message can be transmitted on frames

number 8 and 9.

Then, if the SDCCH is transmitted on the Time Slot 0 of another TDMA than the one carrying

the BCCH, a collision will occur.

In that case, the mobile must choose between an incoming call and a SMS-CB, by selecting

one kind of data to listen.

Setting noOfBlocksForAccessGrant to a value superior or equal to 1 avoids this problem: only

AGCH can be transmitted on that block.

This rule

NoOfBlocksForAccessGrant > 1

is a recommendation requirement on not combined CBCH.

In that case, on the frame number 8 and 9, the MS can just receive an Immediate Assignment.

If an Immediate Assigment message is transmitted, it means that the mobile has sent a

channel request, and is not in idle mode any more. Therefore, the MS won’t listen to theCBCH channel.

Please also refer to chapter Consequences of NoOfBlocksForAccessGrant.




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6.11. IMPACT OF THE AVERAGING ON THE HANDOVERS

The following study applies only to L1M V1.

Simulations have been performed with NMC Engineering tools to determine the impact of

some BSS parameters values in terms of handover reactivity. The simulations were performed

from real RF measurements and network field configuration.

Four Simulations have been performed with the following sets of parameters:

runHandOver Hreqt

1 2 2

2 2 1

3 1 2

4 1 1

The results are spread on three items:

• Global statistics: number of HO in each configuration.

• Study of reactivity: impact of parameters on reactivity.

• Reactivity vs ping-pong.

6.11.1 GLOBAL STATISTICS

HO CAUSE PBGT AND QUALITY DL

For each of the four sets of parameters presented, the amount of HO on quality DL and PBGT

is the same.

HO CAUSE LEVEL DL

The modification of the parameters has a low impact on the total amount of HO detected on

Level DL cause.

HO CAUSE CAPTURE

For each of the four sets of parameters used, the total amount of handovers is the same. The

difference is not significant because microCellCaptureTimer * runHandover is kept constant.

CONCLUSION

The simulations show that:

• Setting Hreqt=1 instead of 2 has a very low impact on the total

amount of handovers (less than 4%)

• Same conclusion for runHandover=1 instead of 2




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6.11.2 STUDY OF REACTIVITY

The second item of the study is to show the impact of runHandover and Hreqt on the

reactivity: how much sooner do the handovers occurs ?

RUNHANDOVER=1

Field simulations have shown that such a value of runHandOver has low impact on reactivity

compared to runHandOver=2. The increase of reactivity due to runHandOver=1 is less than or

equal to 0,5 second.

HREQT=1

The influence of Hreqt on reactivity is much more decisive, 15% are being advanced by setting

Hreqt=1 (hoMargin unchanged). Two reasons can explain this:• After the beginning of communication on a new TCH, L1M waits for a fixed

delay before a new HO: HreqAve*Hreqt*0,48 sec. Among the HO performed

within 8 seconds1 after a callsetup or another HO, 45% are advanced thanks

to Hreqt=1.This can be very helpful if, for example, the callsetup was initiated

on a bad cell, because of Reselection failure.

• Reducing the length of the weighted averaging window can make the

variations of the weighted average less smooth. This effect is observed for

only 2% of the HO. For this particular case, it is still possible to tune hoMargin.

The low impact of this measure can be explained as follows.

HREQT=2

That configuration does not always double the size of the averaging window.

Example: runHandover=1, HreqAve=4, Hreqt=2. Every runHandover, the L1M calculates a

weighted average based on the last average stored and the sliding average of the moment.

These two averages can have up to 3 measures in common.

CONCLUSION

• Hreqt=1 is an efficient way to increase reactivity for 15% of the HO.

• Among the HO performed within 8 seconds (after call setup or another HO),

45% are performed sooner with Hreqt=1 (in average 1,6 sec sooner).

• Among the HO performed long after the beginning of the communication, only

2% are performed sooner because Hreqt=1 makes the weighted average less

smooth.It is still possible to tune hoMargin.

• runHandOver=1 can not advance HO of more than 0,5 sec.

6.11.3 PING PONG VS REACTIVITY

Among the 15% of HOs that were advanced for more than 1 second by Hreqt=1, simulations

show that without changing hoMargin, no supplementary ping pong handover was observed.




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6.12. IMPACT OF CALL RE-ESTABLISHMENT ON THE NETWORK

6.12.1 IMPACT ON CAPACITY

The Call-Reestablishment feature has a big impact on the MSC resources occupation. Without

Call Re-establishment, T3109 (BSC timer) is usually set to a small value (>

Min(radioLinkTimeOut, 4*rlf1+4) which is given in SACCH block) in order to free resources as

soon as possible after a radio link failure (see t3109 recommanded value).

Setting a large value to T3109 for Call Re-establishment leads the MSC to freeze the resource

for the call waiting for a Channel Request from the MS. Therefore, if the MS is unable to select

a destination cell, or if the radio link failure is due to coverage limits (border cells), the

resource is frozen for nothing.

Call Re-establishment should not be activated on border cells, or the impact could be reduced

by decreasing the value of T3109 on these specific locations.

On the other hand, on Sunday network, tests have been performed showing that, after the Call

Re-establishment activation, nearly no trunk erlangs have been noticed by Mandarin Radio

Engineers.

Please also refer to chapter Call reestablishment procedure (Cr).

6.12.2 IMPACT ON CALL DROPS

The Call Re-establishment doesn’t decrease the amount of call drops from a counter point of

view, even if it improves the quality of service. The subscriber is satisfied to get back hiscommunication after few seconds instead of totally loosing it, but this procedure is launched

after a call drop detection, counted by the system.

Moreover, the Call Re-establishment can increase in some cases the overall number of call

drops. For instance, when a temporary destination cell is selected by the MS without providing

a long term solution:

The operator can deduce that Call Re-establishment has a bad influence on call drops

amount. Actually, the communication lasts longer, maybe allowing the subscriber to end his

call properly.




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6.13. MINIMUM COUPLING LOSS (MCL)

The Minimum Coupling Loss is the minimal value recommended in the link budget to avoid

problems in the transmission.

The MCL is calculated to avoid the two major problems which may occur, broadband noise

and blocking. It is mainly used in a micro-cellular and pico-cellular environment where MSs are

likely to operate in the vicinity of the BTS antennas.

6.13.1 BROADBAND NOISE

The Broadband noise takes into account all kinds of noise which disturb the BTS and the MSs.

According to GSM Recommendation 05.05, the MS must keep its output noise level 60 dB

below its power level (for a frequency spacing of 600 kHz). On the BTS part, the received

noise level must be at least 9 dB below its sensitivity.

The decoupling value is the difference between the maximum output noise level and the

maximum received noise level.

Considering a S2000L BTS and a GSM 1800 MS, values are the following in both uplink and

downlink:

UPLINK DOWNLINK

Transmitter Max Power A (dBm) 30 33

Output Noise Level Margin B (dB) 60 60

Max Output Noise Level C (dBm) = A - B -30 -27

Receiver Sensitivity D (dBm) -104 -101

Input Noise Level Margin E (dB) 9 9

Max Input Noise Level F (dBm) -113 -110

Noise Decoupling Value G (dB) = C - F 83 83

As we can notice in the results of the upper table, the values are the same for uplink and

downlink.

6.13.2 BLOCKING

The Blocking takes into account the interferences generated by the others MSs.

The BTS can handle, for the 600 kHz adjacent frequency, a received signal strength 35 dB

below the maximum received power of the current frequency. Over this value, a phenomenon

of flashing occurs.

The flashing phenomenon consists in a BTS or a MS which would emit at a very high value,

and would by this way interfere the communication of the others MSs. The effect of this

phenomenon is the deterioration of the wanted signal.

The decoupling value is the difference between the maximum output power and the maximum

received signal level.

Considering an S2000L BTS and a GSM 1800 MS, values are the following in both uplink and

downlink:




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UPLINK DOWNLINK

Transmitter Max Power A (dBm) 30 33

Max Received Signal Strength B (dB) -35 -44

Decoupling Value C (dB) = A - B 65 77

Moreover, in the blocking case, the probability of collision of the burst between MS and BTS

must be taken into account.

In the blocking case, the downlink is more affected than the uplink. However, this difference is

not very important (except if the study is done at the frequency of the interferer) since the

decoupling value for the Broadband noise is more restricting than the decoupling values for

blocking.

6.13.3 HOW TO IMPROVE THE MCL

If the MCL is not respected, the communications will be deteriorated and will have a poor

quality. To improve that quality (or decrease the probability of such problems to occur), its to

say respect the MCL, solutions consist in increasing the frequency spacing between the cell

and the neighboring cells and/or ensure a better decoupling between BTS antenna and MS.




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6.14. MICROCELL BENEFITS

Microcell is a spectral efficiency feature. This algorithm enables us to shift traffic irrespective of

the traffic condition based on downlink signal strength and mobile speed. This gives flexibilityin filling the micro layer first before loading the macro/umbrella layer.

Different gain can be obtained depending on microcell deployment strategy, e.g. capacity gain,

indoor coverage gain, voice quality improvement… Several microcell strategies should be

considered:

6.14.1 FREQUENCY SUPER REUSE

In a good isolated micro layer network, a separated frequency plan can be allocated for

microcells with a few frequencies for BCCH and high fractional reuse pattern increasing

spectral efficiency increasing capacity keeping same QoS.

6.14.2 TRAFFIC HOMOGENIZATION

One of the most critical frequency plan challenge is high configuration sites. Indeed they are

difficult to control since they create interferences with no way to minimize the collisions.

Declaring cells as microcell allows shifting traffic and homogenizes site configurations having

a cleaner frequency plan.

Benefits of this feature could be realized by rearranging the DRX counts and carrying more

traffic in the micro layer traffic channels and simultaneously carrying lesser traffic and DRXs in

the umbrella layer thus giving room to reduce spectrum from the Macro layer which is moreinterfered. This allows a cleaner and more manageable frequency plan avoiding high

configurations

6.14.3 RADIO CONDITIONS IMPROVEMENT

Cells with low antenna height are normally better isolated by environment protection. If these

cells are declared as micro, shifted traffic generates less interference creating a cleaner

frequency plan. Less interferences are traduced in a better voice quality or feasibility to

increase fractional reuse pattern keeping same voice quality.

On one hand microcell deployment is a good strategy to improve radio conditions., thus the

operator can whether increase fractional reuse and therefore increase network capacity or

increase voice quality, keeping same fractional reuse pattern.

On the other hand, microcell deployment is a good strategy to improve indoor coverage in a

specific area, such as business or travelling hot spots.




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6.14.4 MICROCELL FIELD EXPERIENCE

MICROCELL IMPACT ON AMR HR PENETRATION

Microcell deployment reduces AMR HR penetration. Indeed, in microcell PBGT HO are

disabled, and yet when PBGT HO are activated we assume to be on the best serving cell, so

in the best C/I conditions. This effect has an impact on AMR HR penetration as good C/I

conditions are required for Half Rate, which slightly reduces its penetration.

LRXLEVDLH AND LRXLEVULH DEFINITION

When a micro to umbrella relationship is declared between two different cells, it is important to

have a close look on Call Trace / Call Path Trace in order to determine lRxlevDLH and

lRxlevULH. Depending on micro and macro cell layer design, it has been found some caseswhere a call, which is allocated in the micro cell and getting close to the micro cell limits,

receives an RxLev signal from the macro cell which is even lower than micro cell RxLev

signal. Since Power Budget is deactivated when micro-umbrella relationship is declared, this

phenomenon makes that rescue RxLev handover rarely executed and calls are dragged until

quality handover is triggered, which could happen too late to save the call, increasing the call

drop rate.

In this case, it is recommended to analyze with CT/CPT the level of microcell and the

neighboring macrocell level received to declare the suitable value where level handover can

safely occur.




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6.15. INTERFERENCE CANCELLATION USAGE

All the field results so far lead to the following conclusion:

• 50% for interferer cancel algo usage is a very good compromise between

interference cancellation and pure thermal noise sensitivity: it does not

degrade the sensitivity and gives almost the same interference cancellation

performance as 100% with 5dB cancellation loss in the range I/N=0 to 20dB.

For instance, it will be very useful in a medium traffic area, where the isolated

interferers will be very well removed with no coverage degradation.

• When pure thermal noise sensitivity is not an issue (not coverage but

interference limited situation), 100% achieves the best interference

cancellation.

• In an actual network, some particular synchronization patterns may exhibit a

performance loss when interference cancellation is applied although there aremany interferers. However, on the overall network a typical net gain of about

1dB will be obtained with 50% (remember that 1dB is 26% increased capacity

if the network capacity is limited by the uplink interferers).

The following guidelines should be applied: when the interference cancellation is available,

50% is an excellent compromise between coverage and interference cancellation. When

speed is the main problem (high speed train coverage) 100% is the best value.

Improvement appears when there is an update from a previous v15.1.1 BSS to a later one.

Indeed, before V15.1.1, gain of interferer cancellation was not optimal in case of low Rxlev.

Since V15.1.1 interferer cancellation algorithm has been improved to take into account all

range value for parameter “interferer cancel algo usage” for all RxLev range.




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6.16. STREET CORNER ENVIRONMENT

6.16.1 DESCRIPTION

Especially in micro-cellular network, where the antennas are under the roof, the level received

by the mobile can dramatically fluctuate. Ping pong handovers and call drop were experienced

in this type of environment, and led to bad quality of service as well as a significant increase in

signalling traffic. One of the toughest issues to solve in a micro cellular network is street corner

environment.

Two cases must be distinguished:

• The first one deals with mobile moving straight the cross road. In the case, the

handover toward the cell A must be avoided.

• Mobiles turning at the cross road is the second case. The handover from cell

B to A must be performed quickly before the field of the current cell dropped

under a critical value, leading a call drop.

cell A

cell B

cell A

cell B




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6.16.2 CASE A: MOBILE MOVING STRAIGHT

In the case of a mobile moving straight the cross road, a handover for PBGT may be

processed from cell B to cell A. Once the cross is passed, the mobile is handed again over thecell B. This ping pong handover shall be avoided as useless handover leads to voice quality

degradation.

The parameter rxLevDLPBGT allows to cope with that case. Actually, if the signal received by

the mobile from the serving cell exceeds this threshold, then the handovers with power-budget

criteria are prevented.

cell A

cell B

cell A

cell B

RxLev

Time

rxLevDLPBGT

cell A

cell B

RxLev

Time

rxLevDLPBGT

cell A

cell B




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6.16.3 CASE B: MOBILE TURNING AT THE CROSS ROAD

In a microcell environment, the size of cells is very small (40 to 400 meters). The overlapping

margin between cells is not very important. Moreover, a fast moving mobile may cover a fewhundred meters during the handover process (in the worst configuration, the duration time of a

handover can be more than 1.5 s). The overlapping margin can be insufficient to prevent the

field of the current cell from dropping under a critical value before mobile locks on the next cell

(with standard parameters values). In such environment, reactivity is essential, handovers

have to be performed as quickly as possible.

The problem is solved by the combination of the following features:

• Early Handover decision (see chapter Early HandOver Decision)

• Protection against runHandOver = 1: in a microcell environment reactivity is

essential (see chapter Protection against RunHandover=1).

• Max rxLev for PBGT: the problem of handover toward cell A when mobile

goes straight forward is solved by a negative hoMargin for PBGT that can be

set in order to help handover when mobile turns (see chapter MaximumRxLev for Power Budget)

cell A

cell B

cell A

cell B

RxLev

Time

cell A

cell B

RxLev

Time

cell A

cell B




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6.17. SYNCHRONIZED HO VERSUS NOT SYNCHRONIZED HO

6.17.1 INTRODUCTION

Some tests have been carried in order to compare the timing HO of the three kinds of

handovers. No interBSC handovers were performed as synchronized handovers are only

available for intraBSC HO.

The test plan was the following:

Intra BSC / Intra BTS HO

• Not synchronized HO from Cell A to Cell B (UL & DL)

• Synchronized HO from Cell A to Cell B (UL & DL)

• Pre–synchronized HO from Cell A to Cell B (UL & DL) with different values of

the PresynchTimingAdvance parameter.

Intra BSC / Inter BTS HO

• Not synchronized HO from Cell A to Cell B (UL & DL)

• Pre–synchronized HO from Cell A to Cell B (UL & DL) with different

• values of the PresynchTimingAdvance parameter.

6.17.2 OMC-R PARAMETER SETTINGS

It has to be noted that ECU was enabled on both Cell A and Cell B. ECU may have an

influence on UL measurements.

SYNCHRONIZED HO

Parameters Cell A Cell B

adjacentCellHO object

CellId Cell B Id Cell A Id

Synchronized Synchronized Synchronized

hoMargin -24 -24

NOT SYNCHRONIZED HO


adjacentCellHO object

CellId Cell B Id Cell A Id

Synchronized Not Synchronized Not Synchronized

hoMargin -24 -24




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PRE-SYNCHRONIZED HO


AdjacentCellHO objectCellId Cell B Id Cell A Id

Synchronized Pre sync HO with timing advance Pre sync HO with timing advance

PreSynchroTA

0

1

2

3

4

5

6

30

0

1

2

3

4

5

6

30

hoMargin -24 -24

Note: the value - 1 for the PreSynchroTA parameter stands for a TA value equal to 1 (554 m).

6.17.3 TIMING HO

PROCEDURE

The test procedure was based on tone recordings. A specific tone is sent for UL (resp. DL)

from the MS (resp. the land line). The tone is a pattern of a 3 second 500 Hz signal and a 3

second 700 Hz signal. The use of 2 contiguous signal is needed because problems of no

signal emission occurred when a one frequency tone signal is used.

The tone was sent for a minute. An HO occurred approximately every 5,7 seconds. Each

record has a serial of about 10 HOs.

All the averages shown in that study are calculated from these 10 values.

SYNCHRONIZED HO RESULTS

COLLECTED DATA

HO # Muting (ms) Silence (ms) Demuting (ms) Total (ms)

1 26 55 28 109

2 14 60 21 95

3 21 57 15 93

4 31 61 14 106

5 14 52 15 81

6 26 50 19 95

7 70 26 19 115

8 66 28 26 120

9 43 25 46 114

10 49 10 38 97

11 29 18 36 83




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The (1,2,3,4,5,6) HO # are HOs which occurred in the 500 Hz frequency part of the tone.

The (7,8,9,10,11) HO # are HOs which occurred in the 700 Hz frequency part of the tone.

STATISTICS & COMMENTS

• HOs in 500 Hz frequency tone part

Muting (ms) Silence (ms) Demuting (ms) Total (ms)

22 56 19 97

14 50 14 78

31 61 28 120

7 4 5 16

• HOs in 700 Hz frequency tone part

Muting (ms) Silence (ms) Demuting (ms) Total (ms)

51 21 33 106

29 10 19 58

70 28 46 144

17 7 11 35

For both frequencies, the average timing HO of a synchronized HO is the same, around 100

ms. The interesting part is that the time repartition between the muting, silence and demuting

phases are not the same.

The muting and demuting phases appear to be dependent on the frequency. However, the

muting and demuting algorithms at the TCB are not dependent on the frequency. Actually, the

ECU activation on both cells may be responsible of this dependence. It seems that the ECU

algorithm at the BTS makes the muting and demuting dependent on frequency.

When ECU is enabled, it seems that the muting and demuting slopes are correlated to the

frequency.

NOT SYNCHRONIZED HO RESULTS

COLLECTED DATA

HO # Muting (ms) Silence (ms) Demuting (ms) Total (ms)

1 25 133 4 162

2 47 113 84 244

3 40 114 43 197

4 20 137 47 204

5 24 131 43 198

6 48 93 33 174

7 18 123 46 187

8 38 143 38 219

9 25 109 44 178




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The (1,2,3,4,5,6,7,8,9) HO # are HOs which occurred in the 500 Hz tone part of the signal.

STATISTICS & COMMENTS

Muting (ms) Silence (ms) Demuting (ms) Total (ms)32 122 42 196

18 93 4 162

48 143 84 244

12 16 20 25

The Not Synchronized Timing HO is around 200 ms. Unfortunately, the high standard

deviation value does not allow any conclusion on this specific duration.

Note: Not synchronized HO procedure

Here is a brief example of the L3 radio protocol of such a HO:

• DL: HANDOVER COMMAND

• UL: HANDOVER ACCESS

• DL: PHYSICAL INFO



• UL: HANDOVER COMPLETE

The TA is indicated from the target BTS to the MS in the PHYSICAL INFO.

We can make the statement that the not synchronized HO is twice slower than the

synchronous one. It is mainly due to the PHYSICAL INFO expectation of the MS.

PRE-SYNCHRONIZED HO RESULTS

PRINCIPLE

The pre-synchronized handover procedure is exactly the same than the synchronized

handover procedure.

After the Handover Access bursts which shall be sent with a TA value of 0 the MS shall use a

TA as specified in the HO Command by the old BTS, or a default value of 1, if the old BTS did

not provide a TA value.

The BSC indicates in the HO Command message that the handover will be pre-synchronized

and, if needed, the predefined Timing Advance to be used by the MS in the new cell

(preSynchroTimingAdvance parameter).

COLLECTED DATA

The real TA of both cells is 0 (but fluctuant sometimes to a TA value of 1). The aim of these

tests is to evaluate the voice quality loss and/or gain of a pre-synchronized HO versus the

preSynchroTimingAdvance value set at the OMC-R.




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STATISTICS

PreSynchroTA (kms) 0 -1 1 2 3 4 5 6 30

Average (ms) 120 122 89 105 436 739 756 684 705

Minimum 108 94 65 89 79 524 606 532 533

Maximum 129 144 126 105 958 971 970 947 945

Standard Deviation 8 18 17 13 334 172 133 132 133

COMMENTS

It has to be understood that the pre-synchronized handover has been implemented in order to

fasten the handover procedure in a dense (size <2kms) environment or in a railway / highway

optimization. As the setting of the preSynchroTimingAdvance parameter is not that easy (on-

field measurements and TA distributions after HO per pair of cells), the behavior of the MS for

a wrong (2 or 3 steps of TA) and a very wrong (greater than 3 steps of TA) TA value is very

interesting for the network optimization.

Actually, regarding the timing HO results versus different preSynchroTimingAdvance values, it

seems that the MS is able to re-synchronize with the BTS. The drawback is that the speech

cut duration and the handover procedure are highly increased (up to 1 second).

CONCLUSION

Regarding the results of that study, it clearly appears that the synchronized handover is the

faster type of handover. It is available for intraBTS or intracell handovers, or if the Network

Synchronisation is activated. In this case, if the two cells are synchronized by GPS, and they

have the same TNOffset, handover can be synchronized, even if the two cells are not in the

same BSC.

However, the pre-synchronized handover has shown very good results (almost the same

performance than the synchronized one) if the TA after HO is previously known.

Therefore, pre-synchronized HO is a good solution to fasten handover and to decrease (up to

80 ms) the speech cut duration. The fields of appliance should be dense (cell size < 2kms),

railway or highway environment to ensure that the distance after handover is known.

Not synchronized handover still remains the only setting for InterBSC handovers.

Anyway, the UL results of that memo show that the speech cut duration is less than 250 ms.

This value allows to keep a pretty good voice quality during handovers.




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6.18. BTS SENSITIVITY

6.18.1 DEFINITION OF SENSITIVITY

In this chapter, sensitivity figures are clarified, knowing that such notions as static, dynamic,

guaranteed and typical may often lead to confusion.

The sensitivity is completely defined in the GSM recommendation 05.05. §6.2., as the input

level for which all performances in terms of frame erasure, bit error or residual error rates are

met. A reference table specifies rates varying according to the type of GSM channel (traffic,

signaling) and the type of propagation channel (static, urban, rural, hilly terrain).

Sensitivity is measured at antenna connector, and by definition this figure takes into account

all RF elements losses included in BTS cabinet, as shown on the following figure:

Base Station

Rx diversity gain

Duplexor

Combiner

Power Amplifier

Antenna connector

Antenna

Common

Cable losses

Rx sensivity

Base Station

Rx diversity gain

Duplexor

Combiner

Power Amplifier

Antenna connector

Antenna

Common

Cable losses

Rx sensivity




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6.18.2 STATIC AND DYNAMIC SENSITIVITY

Static sensitivity could be viewed as the level at which sensitivity performance is met in the

static channel mode. Yet, the static mode is only one of the propagation models among others

specified in the GSM Recs. reference table. The static mode is the most favorable case(excepted a few cases of fully not correlated antennas and 2-branchs diversity). In terms of

radio, it can be understood that for a given signal input, less communication errors are

expected within a configuration where there are no multi-path effects at all.

6.18.3 TYPICAL / GUARANTEED SENSITIVITY

Typical sensitivity is 1dB better than the worst-case used, mainly due to the variation in

performance of the RF front end and not the variation in the DRX module. The variation in

performance of DRXs on a per cell basis is therefore very tightly controlled. For more details,

please refer to the BTS Engineering Rules ([R47] to [R56]).

6.18.4 SPACE DIVERSITY GAINS

FADING CORRELATION

One major parameter to assess space diversity gain is the fading correlation, which depends

on many factors, such as radio environment (angular distribution of reflectors), antenna

configuration (spacing between antennas) and position of the mobile respective to the BTS.

The sensitivity for fully correlated antennas and not correlated antennas (correlation 0.2) can

be viewed respectively as the worst case and quasi-best case situations. In reality, the

correlation figure lies ‘somewhere between’ both figures, depending on the factors mentioned

previously.

To assess correlation values applicable to engineering is not an easy task. Yet, it can be

observed that by taking 10 wavelengths of antenna separation (recommended distance is 20),

the correlation factor is as low as 0.2 for an angular spread of only 1 degree .These results

give us enough confidence to interpolate the sensitivity at values near the not correlated case,

in such environments as built-up areas (urban, suburban), as well as hilly terrain, which offer a

multiplicity of reflectors. However, this appears less obvious for open area environments,

typically flat rural, for which we will assume a more conservative correlation factor.

BRANCH SENSITIVITY

Diversity gains are calculated by doing the difference between “with” and “without” 2 antennas

figures. Then diversity gains vary a lot with correlation and propagation channels. Yet, it can

be observed that after rounding figures, the overall sensitivity + diversity figure stays relatively

constant, independently of the configuration. The trend is a cumulated figure of -113 dBm for

the S8000 without enhanced coverage option, and -115 dBm for the S8000 with enhanced

coverage option.

This observation partly justifies the uniformity of the diversity gain of 5 dB for the S8000. It

must be stressed that this artifice is only meant to provide separate figures for sensitivity and

diversity gain, which are still distinguished when discussing link budgets




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6.18.5 CROSS-POLARIZATION ANTENNA USE

The use of cross-polarization antenna has followed a growing trend, due to the flexibility

offered in terms of site installation (two antenna packaged into one, offering diversity gain and

coupling 2 TRXs on a single antenna without hybrid coupling).

Cross polar antenna is characterized by:

• 2RF ports for one antenna

• slant polarized transmission.

Hence use of cross polar antennas implies:

• simplification of the coupling stage.

• radio link performances modification.

• diversity of polarization.

SIMPLIFICATION OF COUPLING STAGES

It should be understood that with the same number of antennas as for spatial diversity

crosspolar antennas provide 2 times more RF ports. This means that on one feeder, the

number of supported DRX is divided by two, and the size of the coupling stage too.

RADIO LINK PERFORMANCES

Radio link performances are affected by the transmission over slanted polarization:

measurement reports indicate performances of crosspolar antennas compared to vertical

antenna are lower:

• in urban area of 1dB in 900 MHz and 2dB in 1800 MHz.

• in flat rural area of 3dB in 900 MHz and 1800 MHz.

Note: performances of crosspolar antennas are strongly dependent on environment, and

mainly on reflectors and scatterers: the more they are, the better the performances.

For link budget purposes, crosspolar antennas recommended typical losses are:

• in all environment, 1.5dB in 900 MHz and 1800 MHz.

• in flat open area, 3dB in 900 MHz and 1800 MHz.

POLARIZATION DIVERSITY

Polarization diversity is obtained by processing the two signals coming from the two branches

of one crosspolar antenna. Polarization diversity is estimated after measurements of signal

decorrelation between the two diversity receiving branches of one crosspolar.




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LINK BUDGET FIGURES

Proposed link budget figures for crosspolar antenna use are summarized in the table below:

all environments

900 MHz & 1800 MHz

flat rural, flat open

900 MHz & 1800 MHz

radio link performances (DL & UL) -1.5dB -3dB

diversity gain +4dB (5dB)* +4dB (5dB)*

(*) Crosspolar antennas offer as diversity solution:

• polarization diversity (4dB gain) when 1 crosspolar antenna is used.

• spatial diversity(5dB gain) with 2 crosspolar antennas.

6.18.6 CIRCULAR POLARIZATION AND CROSSPOLAR ANTENNASThis system, Nortel patented, combines two types of advantages:

• the crosspolar antenna benefit of the 2 antennas connectors within one

antenna chassis.

• the robustness of circular polarization against depolarization effect and mobile

positioning.

This system relies on a single 3dB-90° dephaser-hybrid coupler located at the bottom of the

crosspolar antenna feeding the two ports of the crosspolar antenna with exactly the same

feeder length. The system scheme is shown below:

BTS with

polarization

diversity

BTS with

space

diversity

BTS with

polarization

diversity

BTS with

polarization

diversity

BTS with

space

diversity

BTS with

space

diversity




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In term of radio figures, the benefits of the crosspolar antenna use combined with the 3dB-

coupler are:

• the radio transmission is no more affected by the slanted polarization due to

the transmission of the whole signal over a circular polarized wave. Whatever

the position, the mobile receives all the power

• the combining stages are divided by 2

• the diversity gain is:

4dB with 1 crosspolar antenna the polarization diversity gain

5dB with 2 crosspolar antenna the space diversity gain

Recommended figures for this system are

all environments 900 MHz & 1800 MHz

diversity gain polarization diversity

space diversity

+4dB

+5dB

radio link performances

(UL and DL)0dB




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6.19. SDCCH DIMENSIONING AND TDMA PRIORITIES

The aim of this chapter is to define engineering rules associated to SDCCH dimensioning and

TDMA priorities .

6.19.1 SDCCH DIMENSIONING

An SDCCH assignment is provided when one of the following Layer 3 message is received:

• CM Service Request (includes IMSI attach)

• Paging Response

• IMSI Detach

• Location Update

So the number of these messages has to be taken into account in the dimensioning of the

SDCCH channels. Some rules are defined here below.

PARASITE SDCCH ALLOCATION

The level of noise can provide a parasite SDCCH allocation, the BTS seems to receive an

RACH and allocates an SDCCH channel. In this case the SDCCH is assigned for a short

duration (free after T3101 (3 sec by default)). The parasite SDCCH assignment depends of

the BCCH TDMA model.

BTS GEOGRAPHICAL POSITION IN THE LAC

The location update frequency must also be considered for the evaluation of the blocking rate

ratio for SDCCH. For BTS located at the border of a Location Area, a lot of location updates

are performed. Then, the signaling traffic is very high. In this case (as for area with a high

SMS traffic), the number of SDCCH channels must be quite high. Therefore, the blocking rate

ratio to consider for SDCCH must be lower than the-one for TCH.

Thus, a table can be established for the blocking rates to consider, depending on the load of

the network and the kind of signaling.

SDCCH Blocking rateTCH

Blocking rate Middle LAC LAC border

Normal load 2 % 0.1 % 0.1 %

Very loaded 5 % 0.1 % 0.1 %

DOUBLE SDCCH ALLOCATION

The double SDCCH allocation occurs when a second RACH is sent by the mobile before the

Immediate Assignment message of the first RACH is received.

The double allocation issue depends on the numberOfSlotsSpreadTrans value.




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ACTIVATION OF SMS-CB

The SMS-CB is multiplexed with the SDCCH. So the activation of the SMS-CB reduces the

number of SDCCH sub-channels and so the signaling capacity of the BTS. For example:

• SDCCH/4 + SMS-CB => 3 SDCCH available (combined case)

• SDCCH/8 + SMS-CB => 7 SDCCH available (not combined case)

TDMA Model Capacity (erlang)

SDCCH/4 0.439

SDCCH/3 0.194

SDCCH/7 1.579

SDCCH/8 2.057

So the activation of the SMS-CB has a great impact on the signaling capacity of cell (see also

chapter SMS-Cell Broadcast)

Note: in case of SMS-CB, the SDCCH TS number has to be lower than 4 (< 4)

SUBSCRIBERS MOBILITIES

In a high mobility area (rural, highway) a none negligible number of the RACH are requested

for Location Updates. The total number of RACH is then higher than in a low mobility area, it is

then better to increase the number of SDCCH channels.

In a very high mobility area (high speed train) the number of Location Area are generally

reduced in order to avoid a BSS signaling overload due to the LA update. Moreover the TCH

allocation has to be as fast as possible in order to avoid dropped calls set-up. So for the cellswhich are dedicated to the coverage of very high mobility area only, (e.g. cells which cover

only the high speed train railways and not surrounding roads or villages) it is better to reduce

the SDCCH channels number. If the cell is at the boundary of a location area the SDCCH

channels have to be set according to the Location Area update load.

NUMBER OF NETWORKS

The SIM card can contain the Id of only 4 forbidden networks, i.e if there are more than four

networks in a country a mobile can attempted a Location Update on other networks (->

Location Reject). So wherever there are more than four competitors in the same frequency

band it is recommended to increase the number of SDCCH channels.




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6.19.2 TDMA PRIORITIES

It is possible to allocate “priorities” to TDMA frames. Each TDMA has two priorities, each

serving a different purpose :

- the “TRX/TDMA mapping priority”, represented by the parameter priority (transceiver

object)

- the “PCM allocation priority”, represented by the parameter trafficPCMallocationPriority

(transceiver object)

TRX/TDMA MAPPING PRIORITY (PARAMETER : PRIORITY)

This priority defines the order with which the BTS allocates the available hardware resources(the transceivers) to the TDMA frames. In practice, if due to a hardware failure, there are fewer

TRX than TDMA, then only the TDMAs of higher priority will be mapped onto a TRX.

The parameter is called priority (transceiver object).

Among the set of TDMA frames attached to a cell, it is mandatory for the one carrying the

BCCH to have the highest priority allocated and to be the only one to have that priority.

For the TDMA carrying SDCCH channels, that priority should be the second highest priority,

i.e. not as high as the BCCH priority.

For the TDMA carrying only TCH channels that priority should be the lowest.

The generic rule to set the TRX/TDMA mapping priorities is the following :

BCCH TDMA : priority = 0

SDCCH TDMA : priority = 1

TCH TDMA : priority = 2

The typical values for priority of each TDMA model is defined in detail in the Radio Interface

Engineering Rules ([R58]).

PCM ALLOCATION PRIORITY (PARAMETER :TRAFFICPCMALLOCATIONPRIORITY)

The parameter trafficPCMAllocationPriority (transceiver object) defines the priority level of a

TDMA frame for mapping onto a PCM on the A-bis interface. In case of failure of one or more

Abis PCMs, TDMAs of highest such priorities are allocated DS0 on the remaining Abis PCM

links before TDMAs of lower priority.

The engineering rule associated to this parameter will depend on the strategy the operator

wants to use for the corresponding site.

The default engineering rule is to give the lowest priority (255) to the TDMA supporting the

BCCH, because the BCCH is conveyed on a LAPD TS, which is always present. So the BCCHsignalling and the SDCCH signalling is never lost. As the TDMA supporting the BCCH has




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fewer traffic channels than other TDMA, it makes sense to save these other TDMA before

saving the BCCH TDMA.

However, one can privilege:

• the traffic in one of the sectors: for example on a site linked by two PCMs if acell is considered as more important by the operator (strategic coverage), one

can give to the TDMAs of that cell a higher priority than those of the other cell.

Thus, during a PCM failure, those TDMA will be re-configured in priority on the

left PCM.

• circuit traffic instead of packet data traffic, by setting a higher priority for

TDMAs having only TCH compared to TDMA that have also pDTCH




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6.20. ENGINEERING GUIDELINES FOR EXCEPTIONAL EVENTS

This chapter is intended to provide guidelines on how to prepare Nortel GSM networks for

“exceptional events” from an engineering perspective. An exceptional event, as described inthis document, is a temporary event which is known in advance and which will generate an

exceptional high traffic load on the network. Nortel’s estimation is that it is economically not

justifiable to dimension a GSM network for these special events. Commonly, a GSM network

is dimensioned to carry the traffic of the busy hour. The actions proposed in this document are

intended to optimize the behaviour of the network during an exceptional event. The document

covers recommended actions on the NSS and on the BSS. On the NSS, the document

describes a set of recommended verifications that Nortel encourages the operator to do in

order to optimize the DMS behaviour. In addition a set of recommended office parameter

settings on the MSC is given with the aim of optimizing the behaviour of the BSC. On the BSS

side, this document presents the list of strongly recommended verifications and a set of

parameters values to be applied for any wide area special event. Nortel recommends that the

normal parameter setting should be reconfigured after the exceptional event.

On the NSS side, the document is applicable to GSM09, GSM10, GSM11 and GSM12. It is

assumed that all required patches on NSS and BSS are applied. Apart from the paragraphs on

CM, LPP and NSS recommendations in Chapter 4.31.3.1, most of the NSS recommendations

can also easily be applied on non-Nortel NSS equipment.

As signalling is the bottleneck during a high load situation on the BSS, the guiding idea here is

to reduce as much as possible unnecessary signalling during the exceptional event. Nortel’s

estimation is that this should improve the behaviour of the BSC.

The control of this situation is done by various verifications and parameter modifications. Theproposal is organised in 4 main levels:

• Prerequisite

• Basic tuning of parameters

• Overload configuration change

• Other parameter modification

6.20.1 BSS PREREQUISITE

CHECKS

SANITY CHECKS

Should be done at least one month before the foreseen event :

• Verification of the state of the different BSC: no BSC boards should be in a

faulty state

• Recommended values are applied

• Dimensioning rules are respected




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NETWORK:

Each BSC is fully operational and a switchover should be done, LapD load balancing over

TMU, LapD loadsharing, Location Area (LA) sizing,, TCH congestion (this is particularly

important in case of concentric cell use), Call Drop rate, HandOver failure rate (andneighbouring reciprocity).

CHECKS CORRELATED WITH THE SPECIAL EVENT

The Nortel Recommendation is that these checks be done a few hours before the special

event.

LIMITATION OF THE OAM ACTIVITIES

The Operation, Administration and Maintenance shall be minimum. So:

• all Call Traces and Call Path Traces shall be stopped/discarded

• Observations should be limited; temporization for permanent observation

should be set to at least 30 minutes

• Freeze of the network operation: No reparenting activity or NRP should be

performed during the critical period

Moreover, no modification of the network during the special event (such as command files,

OMC commands, …) shall be done.

LIMITATION OF THE SIGNALIZATION TOWARDS THE BSC

• Periodic location updates should be limited on the BSS side (recommended

value for timerPeriodicUpdateMS = 60)

• Operator advertising using SMS should be avoided

• If a degradation of the QoS is acceptable during the corresponding critical

period:

Paging repetition at NSS side should be reduced / suppressed,

Notification of voice mail through SMS should be limited / deactivated

Authentication procedures should be limited / deactivated at NSS level

Ciphering should be limited at NSS level

6.20.2 BSS: SUGGESTIONS FOR PARAMETERS TO BE MODIFIEDFOR THE SPECIAL EVENT

It is suggested that the following parameters be modified before the special event and set

back to the previous value afterwards (when the amount of traffic is back to a ”normal” level):




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These parameters are split into 3 categories.

• The modification of parameters of the 1st category does not lead to any

service interruption. These modifications may be done very quickly and a fewhours before the event.

• Parameters of the 2 nd category are only applied if it can be done without

service interruption (refer to chapter ALGORITHM PARAMETERS).

• Modification of parameters of the 3 rd category is optional and only applicable

on networks in which queuing is already activated. It requires a quite long

preparation and should be decided at least three months before the special

event. It does not lead to service interruption.

Parameters to modify:

• abisSpy = “not in progress”

• unknownCellWarning = “disabled”• interBscDirectedRetry = “not allowed”

• intraBscDirectedRetry = “not allowed”

• Multipaging timer on Abis interface = 200 ms

• maxNumberRetransmission = 1

• bscCapacityLoadReduction dedicated overload mechanism for BSC3000 exist

(see chapter BSC3000 Overload Management)

6.20.3 NSS LEVEL

DMS PREPARATION

Note: the recommendations in this Chapter should also be followed after the exceptional

event.

COMPUTING MODULE (CM)

The Computing Module (CM) of the DMS is protected by a highly efficient overload

mechanism. This mechanism allows the DMS to stand a significant overload.

In order to maintain the craftsperson’s capability to access the DMS in the expected overload

situation, it is suggested that verification is made to ensure that at least the 2 MAP terminalsas well as the ETAS modems are declared as guaranteed background task for the CPU. This

is done by setting for these devices in table TERMDEV the GUAR field to Y. A maximum of 5

devices can be declared in this way. Refer to NTP 411-3001-451 Customer Service Data

Schema Vol 3.

LINK PERIPHERAL PROCESSOR (LPP)

The behaviour of the LPP under heavy traffic conditions can be improved by optimizing the

allocation of BSSAP instances to LIU7s. It should be checked that the following

recommendations are followed.

Context




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Table GSMSSI defines the subsystem instances of the BSSAP local subsystem. These

instances reside on an LIU7 and serve SCCP Class 2 connections between the BSS and the

DMS-MSC.

Table GSMSSI allows the customer to associate BSSAP instances with LIU7s.

BSSAP instances are used only for A-interface messaging. They can be datafilled on any LIU7

in the MSC. Also, there is no restriction that an A-interface LIU7 must have a BSSAP datafilled

against it. However, datafilling the BSSAPs in a non-optimal manner can negatively impact

the DMS-MSC’s performance under heavy messaging conditions.

Further information about table GSMSSI and the BSSAP instances can be obtained in The

CCS7 Application Guide, NTP #411-2231-310. This document includes a datafill example for

GSMSSI.

Recommendations

The recommendation is that all customers apply the following guidelines:

• BSSAP instances in table GSMSSI should only be defined against LIU7s

which have an inservice link to a BSC.

• Each A-interface linkset should at least have one BSSAP instance assigned to

it. The remaining instances (total of 32) should be spread out among the

remaining A-interface LIU7s. Priority should be given to the highest traffic

linksets.

SS7 LINK

Underprovisioned SS7 links can result in link congestion, which potentially inhibit mobile call

processing. It is therefore recommended to audit the link provisioning in the network before thespecial event. During the busy hour the mean link occupancy should not exceed 40%. The

expected subscriber growth in the network has to be taken into account. This check should be

done about 4 months before the special event in order to allow potential HW extensions.

LAC DATAFILL

The Location Area Code (LAC) is a configurable parameter on the BSS and on the NSS (table

LAC). If the values are not the same, Mobile location updates on the MSC will fail. This will

result in all mobiles to repeat the locationupdate attempt. The resulting high signaling load can

decrease stability of the LPP due to the increased signaling traffic. It is therefore highly

recommended to verify that the LAC values on BSS and NSS match up before the specialevent.

BSC PROTECTION

Reduction of the signaling load on the BSC optimizes its behavior in a high traffic situation.

This chapter proposes actions in the NSS, which will help to decrease the signaling load on

the BSC.

SMS VOICEMAIL NOTIFICATION

Most of the GSM networks use voicemail notification via SMS. SMS traffic is real-time cost

intensive on the BSC processors. Furthermore, in a high traffic situation with degraded QoS,




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the Voicemail traffic is expected to significantly increase. The operator should consider to

deactivate the notification of voicemails via SMS. Under very high load the notified subscribers

will not be able to consult their voicemails anyway, due to the high blocking rate at the Air

interface. The deactivation should be done either on the VMS or on the SMSC.

AUTHENTICATION

Authentication in GSM aims at ensuring that only mobiles with an official SIM card can access

the network. Reducing authentication reduces the signaling on the BSS. The operator should

consider to disable the optional authentication activities in the network. This can be done by

modifying parameter AUTH_CONTROL_PARM in table OFCVAR. To configure to a minimum

activity the parameter has to be set as follows

GSM09: AUTH_CONTROL_PARM = NORM_0 PER_0 ATT_0 MO_0 MT_0

IMPACT

It should be noted that even with this minimum setting the authentication procedure will be

executed at the first Attach or Inter-VLR-location update of a mobile at the MSC. This implies

that a reasonable degree of security is reached. The default value of NORM_20 PER_20

ATT_20 MO_20 MT_20 configures that every 20th call, location update and attach will trigger

the authentication procedure. The above described minimum value results in only the first

location update (inter-VLR or attach) to trigger authentication.

The parameter allows to individually set authentication rates for normal (NORM), periodic

(PER) location updates location, Attachs (ATT), mobile originated (MO) and mobile terminated(MT) calls.

PAGE RETRY

The Paging message sent to the BSC is highly costly in terms of BSC CPU processing. After a

timer expires without a response from a mobile, the DMS sends a second Paging message.

Monitoring of live networks has shown that only an insignificant portion of the second paging

message is successfully responded by a mobile. Due to this it is recommended to deactivate

the paging retry. This is done by setting the parameter GSM_PAGE_RETRY in table

GSMVAR to 0.

CIPHERING

Ciphering guarantees confidentiality of GSM communications on the radio interface.

Deactivating Ciphering reduces the signaling on the BSC. The operator should consider

whether the deactivation of ciphering is acceptable during the special event. To deactivate, the

officeparameter GMSC_CIPHERING in table OFCENG of the MSC has to be set to OFF.




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6.21. IMPACT OF AUTOMATIC HANDOVER ADAPTATIONACTIVATION

The Automatic Handover Adaptation feature adapts handover parameters to radioenvironment of each call; taking into account mobile speed and frequency hopping with

BSCe3 The objective is to minimize call drops and bad quality transients.

The feature also has a power control adaptation mechanism in addition to the power budget

handover adaptation.

For a good understanding of this feature, please refer to the Automatic handover adaptation

chapter, or to the Functional Note TF1216 : Automatic handover adaptation ([R17])

6.21.1 RELATED PARAMETERS

All the parameters directly related to this feature are described in the Automatic Handover

Adaptation Parameters chapter, but one should also take into account the following

parameters to monitor an impact of the feature on an existing network.


selfAdaptActivation Use for activate the Automatic Handover adaptation

servingfactorOffset This attribute defines the offset linked to the serving cell, used to decrease the HO margin

neighDisfavorOffset This attribute modifies the offset linked to the neighbouring cell, used to increase the HO marging

rxLevHreqave Number of signal strength measurements performed on a serving cell, used to compute arithmeticstrength averages in handover and power control algorithms

rxNCellHreqave Number of measurement results used in the PBGT algorithm to compute the average neighboring

signal strength

rxLevHreqaveBeg Number of measurement reports used in short averaging algorithm on current cell for signal strengtharithmetic average

rxLevNCellHreqaveBeg Number of measurement results used in short averaging algorithm to compute the averageneighboring signal strength

rxQualHreqave Number of arithmetic averages taken into account to compute the weighted average bit error rate inhandover and power control algorithms. Each is calculated from rxQualHreqave bit error rate (BER)measurements on a radio link

rxQualAveBeg This attribute defines the number of quality measures used by the power control mechanism, incase of hopping TS or fast MS

hoMargin Margin to use for PBGT handovers to avoid subsequent handover, in PBGT formula

hoMarginBeg Margin to be added to hoMargin until rxLevHreqave for short averaging algorithm in order tocompensate the lack of measurements

runHandOver Number of Measurement Results messages that must be received before the handover algorithm ina cell is triggered




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6.21.2 DEPLOYMENT OPTIMIZATION AND MONITORING

The expected gains when deploying Automatic Handover Adaptation feature are:

• Reduce Overall RF Drops

• Improve HO Drops and HO Failures

• RLT drops and BER improvement due to automatic power control effects

• Reduced time at max power due to better efficiency in power control

Hereunder is an example of activation of AHA that shows those improvements.

FIRST ACTIVATION

Activation parameters setting:

Parameter ValueselfAdaptActivation enabled

servingfactorOffset 2

neighDisfavorOffset 2

rxLevHreqave 8

rxNCellHreqave 8

rxLevHreqaveBeg 2

rxLevNCellHreqaveBeg 2

rxQualHreqave 8

rxQualAveBeg 2

hoMargin 4

hoMarginBeg 4

runHandOver 1

That activation has proven some good results, mainly on RF drops and Minute Of Usage, but

also on HO repartition, as shown below:

RF Drop per Erlang EvolutionRF Drop per Erlang Evolution




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As explained in the feature description the algorithm helps in the Urban areas by making

intelligent decisions for Power Budget handovers and reducing interference by more reactive

adjustment in attenuation.

In coverage limited environment the advantage is highly mitigated. In order to capture the

benefits from the feature in the Suburban and Rural areas through reducing rescue

handovers; appropriate recommendations should be applied (see chapter Final recommendedsetting).

Hereunde are the general conclusions about AHA activation:

• RF MoU/Drop improvement follows more closely the reduction in drop due to

handovers. BSCs with good coverage and having interference issues

definitely showed improvement in drops.

• BSCs with good ratio of hopping radios and having reduction in BER showed

some considerable improvement in RLT drops. These were areas where the

UL BER had shown consistent improvement after the feature activation

• BSCs with very low ratio of hopping Sectors OR even with high ratio of

hopping sectors showed NO considerable improvement in drops if they are

coverage limited OR less RF overlap.

Handover DistributionHandover Distribution




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FINE TUNING

FREQUENCY HOPPING CASE

The power Budget handover adaptation in the frequency hopping case ( > 3 SFH per sector)

uses servingfactorOffset to favor the server as suppose to the neighbor in two of the four

cases. So the setting of “-2” for servingFactorOffset means it will actually favor the server OR

in other words disfavor the neighbor greatly. The neighDisfavorOffset is already applied at “2”

dB such that the two cases where you have enough measurements of your server the

effective HOMargin (eff) will be 8 dB when you have not enough measurements in the

neighbor and 6 dB when you have enough measurements in the server as well as from the

neighbor. In the expectation of making better and more handovers decisions on PBGT in

these two case the HOMargin (eff) should be reduced by 2 dB in both these cases in order not

to disfavor the neighbor by effectively HOMargin of “6” OR “4” by tuning the

servingFactorOffset from “-2” to “0”.

Note: experience results presented in this part are done with 8 SFH per sector.

NON FREQUENCY HOPPING CASE

The power Budget handover adaptation in the non-frequency hopping case ( < 4 SFH per

sector) does not use servingFactorOffset to favor the server as suppose to the neighbor. This

case uses the neighborDisfavorOffset and so the HOMargin (eff) remains at 6 and 4 dB for

cases with server having enough measurements. However, the other two cases where the

neighbor is disfavored when the server is not having enough measurements seems to be very

high with the intial settings; HOMargin (eff) ( 4 + 4 = 8 dB). It was recommended to change the

HOMargin (eff) by tuning hoMarginBeg from “4” dB to “2” dB to get effective margin of “6” dB.

Handover QoSHandover QoS




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FINAL RECOMMENDED SETTING

The table below provides the recommended setting to take advantage of AHA activation

depending on the area characteristics:

Parameter Urban area Suburban area Rural area

selfAdaptActivation enabled enabled enabled

servingfactorOffset 0 2 0

neighDisfavorOffset 2 2 2

rxLevHreqave 8 8 8

rxNCellHreqave 8 8 8

rxLevHreqaveBeg 2 2 2

rxLevNCellHreqaveBeg 2 2 2

rxQualHreqave 8 8 8

rxQualAveBeg 2 2 2

hoMargin 4 4 2

hoMarginBeg 2 2 4

runHandOver 1 1 1

Handover QoSHandover QoS




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6.22. HANDOVER FOR TRAFFIC REASONS ACTIVATIONGUIDELINE

The purpose of this guideline is to define a default activation of the feature “Handovers fortraffic reasons” over the whole BSC. This proposal includes also the usage of the feature

“Handover decision according to adjacent cell priorities and load” and the default activation of

directed retry. We remind that HoTraffic must be favoured for traffic reason instead of using

the feature Directed Retry, which is a solution only for occasional cases of congestion.

For a better understanding please refer to the following Functional Notes and chapters:

• [R12] Handover for traffic reasons: TF132

• Handover for traffic reasons

• [R13] Handover decision according to adjacent cell priorities and load TF716

• Handover decision according to adjacent cell priorities and load

• Directed Retry Handover

The objectives of a BSC deployment of that feature would be:

• to reduce current TCH blocking wherever it happens on normal origination

and during HO phase

• to anticipate unexpected TCH blocking in order to improve traffic carried on

originating and ongoing calls

• to facilitate feature activation process by generalising the settings on the

whole BSC

6.22.1 ALGORITHMS AND PARAMETERS DEFINITION

As the Directed Retry handover is intended to re-direct TCH Allocation on a loaded cell to an

other cell, the traffic handover’s objective is to leverage resources blocking when one cell is

overloaded by redirecting the most appropriate calls in progress to neighbour cells with a

PBGT handover procedure.

OVERLOAD CRITERION

The overload criterion is defined on a cell basis and can take two expressions according to the

operator’s choice :

• If queuing is not activated the number of available TCHs is lower than the

defined threshold,

• If queuing is activated: the number of queued TCH requests is greater than

the defined threshold.

That mechanism is decribed in the chapter Congestion determination.

When overload occurs, the BTS sends, on request from the BSC, HO indications including the

list of candidate neighbors n for which the following expression is fullfilled:

EXP2Traffic(n) = Pbgt(n) - [hoMargin(n) - hoMarginTrafficOffset(n)]

Refer also to the chapter General formulas.




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RELATED PARAMETERS


hoTraffic (bsc) enable the traffic HO feature at BSC levelhoTraffic (bts) enable the traffic HO feature at BTS level

hoMarginTrafficOffset level strength margin added to compute the neighbor eligibility in case of traffic HO(refer to EXP2Traffic)

numberOfTCHFreeBeforeCongestion minimum number of free TCHs which triggers the beginning of the TCH congestionphase and the beginning of the traffic overload condition

numberOfTCHFreeToEndCongestion number of free TCHs which triggers the end of the TCH congestion phase and the endof the traffic overload condition

hoPingpongCombination list of couples of causes (HOInitialCause and HONonEssentialCause) to preventpossible HO ping pong due to traffic HO

hoPingpongTimeRejection timer associated to the anti ping pong feature

offsetLoad level strength offset added to compute the neighbor eligibility depending on its state ofcongestion (refer to EXP4)

Furthermore and as described in the chapter Expected effects and recommended parameters,

queuing and directed retry parameters have to be set properly. As a reminder:

• Queuing activation: please refer to chapters Queuing and TCH Allocation

Management Parameters

• Directed retry: please refer to chapters Directed Retry Handover and Directed

Retry Handover Parameters

FEATURE INTERWORKING

In order to avoid blocking the originating calls on congested cells, directed retry with default

settings should be enabled, and to avoid a return from non congested to congested cell after

HO traffic activation two features should be used:

• prevent « ping-pong » effect by applying a protection timer for all incoming

relations onto the congested cell

• prevent a « snow ball » effect by using the load status conditions through the

usage of the offset load parameter in :

EXP4(n) = EXP2(n) – [offsetLoad(n) * stateLoad(n)]




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6.22.2 EXPECTED EFFECTS AND RECOMMENDED PARAMETERS

Let’s consider a cell A passing through different states of congestion and the HO interactions

in its neighborhood.

In a normal phase incoming HO toward cell A can be alarm HO, PBGT HO, or traffic HO

coming from congested neighbor cells.

As the congestion state is reached on cell A, depending on the cell load state and the

associated parameter, some procedures are engaged to try to set back the cell to a non

congested state:

• traffic HO are activated from cell A to its non congested neighbor cells, i.e.

PBGT HO with a smaller margin

• traffic HO are disfavored toward congested cell thanks to Handover decision

according to adjacent cell priorities and load feature

• HO toward cell A are also disfavored

When the cell A succeed in balancing the excess of traffic it reaches again a non congested

cell and the normal procedures are applicable again.

PARAMETER TUNING

As described hereabove the expected behaviour takes benefit from the Handover for traffic

reasons feature that allows to balance calls in good radio conditions toward neighbor cells via

a traffic HO, from the directed retry HO that balance TCH assignment to neighbor cells, and

from the Handover decision according to adjacent cell priorities and load feature that prevents

from oading the cell with unnecessary incoming HO.

Directed retry parameters settings are summarized in the following chapter §4.5.5 and

hoMarginTrafficOffset and offsetLoad parameters tuning is explained hereunder.

Cell A Cell A Cell A

Congested cell

Non congested cell

Overload phaseNormal phase Normal phase

Normal HO (PBGT, Qual, Lev, …)

Traffic HO

Prevented HO on load condition

Cell A Cell A Cell A

Congested cell

Non congested cell

Overload phaseNormal phase Normal phase

Normal HO (PBGT, Qual, Lev, …)

Traffic HO

Prevented HO on load condition




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One can observe on the above figure that using traffic HO is likely to simulate an increase in

the non congested neighbor cell coverage of hoMarginTrafficOffset dB. In order to prevent

outgoing traffic HO from A to B to come back on A an offsetLoad value equal to

hoMarginTrafficOffset is recommended. In that case any attempt of HO from “traffic extended”

B cell coverage to A would be discarded.

offsetLoad ≥ hoMarginTrafficOffset

Furthermore, the correct setting of the anti ping pong feature sould harden that behaviour for

the PBGT HO from B to A.

CAUTION!

The following exceptions should be applied:

• Timer protection should not be set from cells like: indoor, microcells, special

coverage, or any relation with HOmarginPBGT < 0

• Offset load should not be set from cells like: indoor, microcells, special

coverage, or any relation with HOmarginPBGT < 0

Cell A congested

hoMarginTrafficOffset

Offset load

Cell B non congestedCell A congested

hoMarginTrafficOffset

Offset load

Cell B non congested




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RECOMMENDED PARAMETERS

CONGESTION DETECTION

Parameter Recommended value

numberOfTCHFreeBeforeCongestion 10 % of potential ressources for circuit cal ls including preemptable PDTCH

numberOfTCHFreeToEndCongestion 20 % of potential ressources for circuit cal ls including preemptable PDTCH

Note: potential ressources for circuit calls including preemptable PDTCH cans be deduced

from the following metric

(C1700 max value (tchFrAveragedAvailableMax) - AllocPriorityThreshold)

HANDOVER FOR TRAFFIC REASONS ACTIVATION


hoTraffic (bsc) enabled

hoTraffic (bts) enabled

hoMarginTrafficOffset 6 dB

Note: HoMarginTrafficOffset should be tune such as the resulting margin should be equivalent

to the one for rescue HO. This margin can be increase case by case for cell with important

congestion. At on stage it is preferable to add capacity.




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HANDOVER DECISION ACCORDING TO ADJACENT CELL PRIORITIES AND LOAD ACTIVATION


offsetLoad ≥ hoMarginTrafficOffset

GENERAL PROTECTION AGAINST HO PINGPONG


hoPingpongCombination (all, PBGT)

hoPingpongTimeRejection at least 20s

DIRECTED RETRY HANDOVER ACTIVATION


directedRetryModeUsed bts

interBscDirectedRetry allowed

intraBscDirectedRetry allowed

interBscDirectedRetryFromCell allowed

intraBscDirectedRetryFromCell allowed

modeModifyMandatory used

directedRetry - 80 dBm




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6.23. DISABLING AMR BASED ON TRAFFIC IN V15.1.1

Previously to V15.1.1, if hrCellLoadStart > 0, then HR calls can be allocated as long as the

RxLev criterion is matched.

To achieve such a behavior in V15.1.1, since AMR based on traffic is automatically activated,

it is necessary to set the parameters as following:

• filteredTrafficCoefficient = 1

• hrCellLoadStart = 1 (range [0 to 100])

• hrCellLoadEnd = 0 (range [0 to 100])

With this values, the “V15.1 like” behaviour should be reached after nb_of_inService_DRX*10

seconds.

Note: the behaviour with this configuration is based on a theoretical study of the AMR based

on traffic algorithm.

To prevent HR allocation, it is necessary to set the parameters as following :

• hrCellLoadStart = 0 (range [0 to 100])

• amrDirectAllocRxLevUL or amrDirectAllocRxLevDL = more than -48 dBm




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7. APPENDIX A: MAIN EXCHANGE PROCEDURES

AT BSC LEVEL

7.1. ESTABLISHMENT PROCEDURE

SABME: frame to set asynchronous balanced mode (initiate a link for numbered information

transfer).

UA: unnumbered aknowledge




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7.2. CHANNEL MODE PROCEDURE




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7.4. INTRACELL HANDOVER PROCEDURE




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7.5. INTRABSS HANDOVER PROCEDURE

From BTS 1 to BTS 2




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7.6. INTERBSS HANDOVER PROCEDURE

BTS 1 (from BSC 1) to BTS 2 (from BSC 2)




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7.7. 2G-3G HANDOVER PROCEDURE




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7.8. RESOURCE RELEASE PROCEDURE (EXAMPLE)




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7.9. SACCH DEACTIVATION PROCEDURE




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7.10. MOBILE TERMINATING CALL




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7.11. MOBILE ORIGINATING CALL




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8. APPENDIX B: ERLANG TABLE

The table below presents the number of Erlang that are expected with regards to the numberof TCH channels on a given cell and considering a blocking rate of 0,01 %. The computation

follows the Erlang B law.

Additionally, this table gives the number of Erlang expected depending on the AMR Half Rate

penetration.

CAUTION!

The expected number of Erlang with regards to the AMR HR penetration has been calculated

based on an estimation of the gain in capactiy provided by AMR HR. It should not be

considered as contractual but as a good approximation of the expected gain.

% Blocking 2% 2% 2% 2% 2%

AMR HR penetration 0 % 25 % 50 % 75 % 100 %

Number of TCH

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

1920

21

22

23

24

25

26

27

28

29

30

31

32

0,021

0,223

0,602

1,092

1,657

2,276

2,935

3,627

4,345

5,084

5,842

6,615

7,401

8,200

9,010

9,829

10,656

11,491

12,33313,181

14,036

14,896

15,761

16,631

17,504

18,383

19,265

20,150

21,040

21,932

22,827

23,725

0,021

0,230

0,630

1,158

1,783

2,483

3,208

3,972

4,767

5,589

6,434

7,299

8,182

9,082

9,978

10,885

11,800

12,724

13,65614,594

15,540

16,525

17,520

18,524

19,536

20,558

21,587

22,624

23,669

24,643

25,617

26,593

0,022

0,247

0,698

1,324

2,097

3,000

3,882

4,814

5,786

6,794

7,833

8,899

9,991

11,106

12,114

13,119

14,119

15,112

16,09917,077

18,046

19,272

20,517

21,783

23,068

24,374

25,698

27,041

28,403

29,596

30,791

31,989

0,023

0,284

0,849

1,688

2,787

4,138

5,299

6,502

7,732

8,982

10,245

11,516

12,790

14,065

15,360

16,655

17,946

19,234

20,51621,791

23,059

24,579

26,118

27,678

29,257

30,857

32,474

34,112

35,767

37,200

38,629

40,058

0,027

0,365

1,177

2,482

4,294

6,621

8,377

10,152

11,922

13,669

15,385

17,056

18,677

20,241

22,004

23,747

25,468

27,164

28,83430,473

32,082

34,075

36,081

38,102

40,135

42,182

44,240

46,310

48,391

50,467

52,551

54,645




Nortel confidential


33

34

35

36

3738

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

6061

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

8384

24,626

25,529

26,435

27,343

28,25429,166

30,081

30,997

31,916

32,836

33,758

34,682

35,607

36,534

37,462

38,392

39,323

40,255

41,189

42,124

43,060

43,997

44,936

45,876

46,816

47,758

48,700

49,64450,589

51,534

52,480

53,428

54,376

55,325

56,275

57,226

58,177

59,129

60,082

61,035

61,990

62,945

63,901

64,857

65,813

66,771

67,729

68,688

69,647

70,607

71,56872,529

27,569

28,545

29,521

30,498

31,53432,574

33,618

34,664

35,714

36,768

37,825

38,886

39,815

40,741

41,662

42,580

43,493

44,402

45,308

46,426

47,549

48,678

49,812

50,951

52,095

53,245

54,399

55,34456,285

57,224

58,158

59,091

60,019

61,029

62,039

63,048

64,057

65,065

66,073

67,080

68,087

69,258

70,434

71,614

72,798

73,987

75,179

76,377

77,340

78,300

79,25880,215

33,191

34,394

35,600

36,808

37,98839,169

40,349

41,528

42,708

43,886

45,065

46,242

47,306

48,364

49,414

50,458

51,494

52,523

53,546

54,862

56,184

57,513

58,847

60,187

61,533

62,886

64,243

65,34566,443

67,537

68,626

69,711

70,792

71,867

72,937

74,003

75,065

76,122

77,174

78,222

79,266

80,665

82,071

83,482

84,900

86,325

87,755

89,192

90,276

91,358

92,43493,508

41,485

42,908

44,329

45,748

47,24848,750

50,255

51,761

53,269

54,779

56,290

57,803

59,197

60,585

61,968

63,346

64,719

66,085

67,447

68,982

70,519

72,059

73,600

75,144

76,690

78,237

79,786

81,12482,456

83,782

85,101

86,414

87,720

89,092

90,459

91,822

93,181

94,536

95,886

97,232

98,574

100,154

101,738

103,323

104,912

106,504

108,098

109,696

111,137

112,578

114,017115,455

56,748

58,857

60,975

63,100

65,07767,051

69,023

70,990

72,954

74,914

76,870

78,822

80,555

82,272

83,973

85,658

87,327

88,979

90,616

92,628

94,640

96,654

98,667

100,682

102,697

104,712

106,726

108,458110,181

111,893

113,592

115,282

116,961

118,865

120,765

122,664

124,559

126,452

128,341

130,227

132,109

134,307

136,512

138,723

140,939

143,163

145,392

147,628

149,435

151,237

153,032154,822




Nortel confidential


85

86

87

88

8990

91

92

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112113

114

115

116

117

118

73,490

74,452

75,415

76,378

77,34278,306

79,270

80,235

81,201

82,167

83,133

84,100

85,067

86,035

87,003

87,972

88,941

89,910

90,880

91,850

92,820

93,791

94,763

95,734

96,706

97,678

98,651

99,624100,597

101,571

102,545

103,519

104,493

105,468

81,169

82,120

83,069

84,016

85,13186,247

87,365

88,485

89,607

90,732

91,857

92,944

94,033

95,122

96,212

97,303

98,395

99,487

100,581

101,704

102,828

103,955

105,083

106,212

107,342

108,474

109,568

110,663111,758

112,854

113,951

115,047

116,145

117,244

94,578

95,644

96,706

97,764

99,178100,596

102,020

103,448

104,882

106,322

107,765

108,975

110,184

111,393

112,601

113,809

115,017

116,223

117,429

118,717

120,005

121,295

122,587

123,880

125,173

126,467

127,684

128,900130,115

131,331

132,546

133,760

134,974

136,187

116,890

118,324

119,756

121,187

122,918124,654

126,396

128,144

129,899

131,659

133,424

134,758

136,088

137,415

138,736

140,053

141,366

142,675

143,979

145,583

147,190

148,800

150,412

152,025

153,640

155,257

156,717

158,177159,634

161,091

162,547

164,001

165,454

166,906

156,606

158,384

160,156

161,922

164,140166,362

168,590

170,823

173,062

175,307

177,556

179,493

181,428

183,361

185,291

187,220

189,146

191,070

192,993

195,088

197,185

199,284

201,385

203,487

205,590

207,694

209,642

211,588213,531

215,473

217,414

219,352

221,289

223,224




Nortel confidential


9. ABBREVIATIONS & DEFINITIONS

9.1. ABBREVIATIONS

For other abbreviations, refer to [R3].

AMNU Advanced Management Unit

AMR Adaptative Multi-Rate

AMR-HR Adaptative Multi-Rate Half Rate

AMR-FR Adaptative Multi-Rate Full Rate

BCC Base station Colour Code

Last three bits of BSIC code. The BCC is used to identify one of the cellssharing the same BCCH frequency. Neighouring cells may, or may not, havedifferent BCC.

BCCH Broadcast Control CHannel

Common mobile logical channel used for broadcasting system informationon the radio interface

BCF Base Common Function

BDA BSC application database

This database contains all the information objects describing the BSS.

BDE OMC-R operations database

This database contains all the information objects describing the BSS underOMCR management control, and the objects required to manage OMC-Rfunctionalities

BER Bit Error Rate

Method of measuring the quality of radio link transmission

A ratio of the number of digital errors received in a specified period to thetotal number of bits received in the same period. Usually expressed as anegative exponent, i.e:

10-6 means one bit error in 106 bits of transmission, or one in a million

BIFP Base Interface Front-end Processor

Set of BSC functional units managing the interface with BTS

BSC Base Station Controller

BSCB BTS Signalling Concentration Board

Board which concentrates 12 LAPD signalling channels between BSC andBTS into 3 channels




Nortel confidential


BSIC Base Station Identity Code

Code used to identify a base station which allows mobile stations todistinguish the cells sharing the same BCCH frequency. A BSIC is defined

by an (NCC, BCC) combination

BSS Base Station Subsystem

Radio Cellular Network radio subsystem made up of Base StationControllers, one or more remote TransCoder Units and one or more BaseTransceiver Stations

BTS Base Transceiver Station

CA Cell Allocation

Radio frequency channel allocated to a cell

CBCH Cell Broadcast CHannel

Logical channel used inside a cell to broadcast short messages inunacknowledged mode

CC Call Control

Sublevel of layer 3 on the radio interface charged with managing callprocessing

CCCH Common Control CHannel

Common bidirectional mobile control channel, used for transmittingsignalling information on the radio interface

CCH Control ChannelCommon or dedicated control channel

CGI Cell Global Identifier

Global identifier of a mobile network cell. The CGI contains the Location Area Code (LAC), Mobile Country Code (MCC), Mobile Network Code(MNC) and the cell identifier in the location area

CMC Codec Mode Command

CPU Central Processing Unit

Slave BSC processing unit

CPU-MPU/BIFP Central BSC processing unit handling MPU and BIFP functions

dB Decibel

Measurement unit of relative power level defined as 10 log10 (P1/P2) whereP1 and P2 are the power levels.

dBm Power in dB relative to 1 mW




Nortel confidential


DCCH Dedicated Control CHannel

Dedicated radio signalling channel with one SDCCH + one SACCH

DITR Dominant to Interferer TSC Ratio

DLNA Duplexer Low Noise Amplifier

Amplifier installed between BTS and the antenna

DRX Driver and Receiver Unit

Signal processing unit for radio transmission and reception.

DTX Discontinuous Transmission

EFR Enhanced Full Rate vocoder

EIRP Equivalent Isotropic Radiated Power

eMLPP enhanced Multi Level Precedence and Preemption

FACCH Fast Associated Control CHannel

Dedicated signalling channel (Um interface)

FCCH Frequency Correction CHannel

Common frequency synchronization channel

FCH Frequency CHannel

Common frequency synchronization channel

FER Frame Erasure Rate

FH Frequency Hopping

FN Frame Number

FP Frame Processor

FR Full Rate TCH

GSM Global System for Mobile Communications

GSM 900 Radio Cellular Network standard adapted for the 900 MHz frequency band.



HO HandOver: automatic call transfer between two radio channels

HR Half Rate TCH

HSN Hopping Sequence Number

ICM Iinitial Codec Mode

L1M Processor functional unit handling BTS radio measurements

LAC Location Area Code

Code used to identify a location area in the GSM network

LAI Location Area Identity

Geographic identity of a group of cells used to locate a mobile station




Nortel confidential


LB Link Budget

LNA Low Noise Amplifier, part of DLNA system

MA Mobile Allocation

MAI Mobile Allocation Index

MAIO Mobile Allocation Index Offset

MCC Mobile Country Code

MTBF Minimum Time Between Failure

MEU Masthead Electronics Unit

Mini-masthead electronics cabinet. Remote amplifier located between BTSand the antenna

MHz MegaHertz

MMU Mass Memory Unit (BSC)

MPU Main Processor Unit (BSC)

Set of BSC functional units charged mainly with call processing functions

MNC Mobile Network Code

Mp Measurement processing

MRC Maximum Radio Combiner

MS Mobile Station

MSC Mobile Services Switching Center

MCL Minimum Coupling Loss

MTBF Mathematical Time Between Failure

It is a mathematical time expectancy between two successive parts ofequipment or unit failure

NCC Network Colour Code

First three bits of the BSIC code. Each country is assigned a list of NCC.

NMC Network Management Centre

NSS Network and Switching SubSystem

Radio Cellular Network subsystem including an MSC, main HLR, VLR, EIRand AUC

NS/EP National Security and Emergency Preparedness

OMC Operation and Maintenance Centre for the radio subsystem

OMC-R Operation and Maintenance Centre - Radio

OMC-S Operation and Maintenance Centre - Switching

OMU Central BSC Operation & Maintenance Unit

OSS Operation SubSystem




Nortel confidential


Radio Cellular Network operations subsystem including the OMC-R andOMC-S

PA Power Amplifier

PBGT Power Budget

PC Power Control

PCH Paging CHannel

Common subscriber radio paging channel

PLMN Public Land Mobile Network

PSTN Public Switched Telephone Network

PURQ-AC Public Use Reservation for Queuing – All Calls

RACH Random Access CHannel

Common mobile logical channel, reserved for random access requeststransmitted by mobile stations on the radio interface.

RF Radio Frequency

RLC Radio Link Counter

RX BTS receiver

RXLEV Received signal Level

RXQUAL Received signal Quality

SACCH Slow Associated Control CHannel

Slow logical control channel associated with a traffic channel during acommunication

SCH Synchronization CHannel

Common time division synchronization channel

SDCCH Standalone Dedicated Control CHannel

Dedicated radio signalling channel temporarily allocated during call set up.There are 2 types of SDCCH: SDCCH/8 and SDCCH/4, on which the logicalchannels are grouped by 8 and by 4 respectively and combined with CCH

SFH Slow Frequency Hopping

SFH mobile mobile using an hopping channel

Non SFH mobile mobile using a non hopping channel

SICD Serial Interface Controller LAPD

BSC board controller for Abis and Ater Interface

SNR Signal to Noise Ratio

SPU Signal Processing Unit

SUP SUPervision unit

Functional BSC monitoring unit




Nortel confidential


SWC SWitching matrix Controller (BSC 6000)

TA Timing Advance

Alignment process designed to compensate propagation time between amobile and base station

TCH Traffic CHannel

Radio traffic channel

TCH/F Traffic CHannel/Full rate

TCH/H Traffic CHannel/Half rate

TDMA Time Division Multiple Access

Abbreviation used to designate a transmission frame on the radio interface,divided into eight time slots (TS) or channels

TMU Traffic Management Unit

TRX Transmission/reception subsystem of the BTS

TS Time Slot

TSC Training Sequence Code

TSCB Transcoder Signalling Concentration Board (BSC)

Board which concentrates LAPD signalling channels between BSC and TCUinto a single channel

TX BTS transmitter

WPS Wireless Priority Service




Nortel confidential


9.2. DEFINITIONS

CODEC MODE

Codec mode is used to designate one of the 8 AMR vocoder and identified using its rate

(12k2, 10k2, 7.95, 7k4, 6k7, 5k9, 5k15, 4k75) give in kbps.

CONCENTRIC CELL

Two concentric geographical zones delimited by distance and level criteria (outer zone and

inner zone).

DUAL BAND CELL

Each group of TRXs is dedicated to a frequency band (900 and 1800 MHz for example) with

different radio propagation condition; the frequency band used for the largest zone (outer) is

the one used by the mono-band MS already existing in the network, since a mono-band MS

must still be able to decode the common channels.

DUAL COUPLING CELL

Each group of TRXs is dedicated to a frequency band and the two groups of TRXs are

combined with coupling systems with different losses, resulting in different coverage areas

with the same TX transmission power.

OuterzoneInnerzone

BCCH and

signallingchannels

trafficchannels

OuterzoneInnerzone

BCCH and

signallingchannels

trafficchannels

Outerzone

band0GSM (or DCS)


BCCH and

signalling

channels

traffic channels

Outerzone

band0GSM (or DCS)


BCCH and

signalling

channels

traffic channels




Nortel confidential


ERLANG

Unit of telecommunications traffic intensity.

The number of erlangs represents the average number of resources or circuits occupied

during the peak traffic hour.

FREQUENCY LOAD

Defines the load of a frequency hopping pattern and is evaluated as below:

fl = Nb of hopping TRX in the cell / Nb of frequencies in the hopping law

FREQUENCY HOPPING: AD-HOC

The Ad-Hoc frequency hopping does not reproduce a pattern all over the network. Frequency

planning is done (HSN, MAIO, MA lists) according to the interference matrix. The particularity

is that the number of hopping TRX = the number of hopping frequencies in most of the cases.

FREQUENCY HOPPING PATTERNS: 1X1

This frequency pattern is used in case of frequency hopping. Each hopping TRX of 1*1 cell,

uses all frequencies of the frequency law:

FREQUENCY HOPPING PATTERNS: 1X3

This frequency pattern is used in case of frequency hopping. Each hopping TRX of 1*3 cell,

uses 1/3 frequencies of the frequency law:

OuterzoneH2D

InnerzoneH4D

BCCH and

signallingchannels

traffic

channels

OuterzoneH2D

InnerzoneH4D

BCCH and

signallingchannels

traffic

channels

f1,f2,f3,f4

f1,f2,f3,f4 f1,f2,f3,f4

f1,f2,f3,f4

f1,f2,f3,f4 f1,f2,f3,f4




Nortel confidential


MULTIZONE CELL

Used in order to refer following kinds of cell:

• concentric cell (see above)

• heterogeneous coupling cell (see above)

• dual-band cell (see above)

RADIO INTERFACE

Interface between the mobile station (MS) and the BTS.

SPEECH FRAME

Corresponds to 20 ms of speech on the radio interface and theTRAU interface.

TIMING ADVANCE

Delay used to compensate propagation time between mobile and base station.

UM-INTERFACE

See “Radio interface”

WPS CALL

Call which has priority level set in the Assignment Request or Handover Request between 2

and 6 (3GPP TS 48.008)

f1,f2,f3

f7,f8,f9 f4,f5,f6

f1,f2,f3

f7,f8,f9 f4,f5,f6




Nortel confidential


10. INDEX

All the parameters listed in the chapter ALGORITHM PARAMETERS are listed and indexedhere below:

accessClassCongestion, 343adaptiveReceiver, 449adjacent cell umbrella ref, 358allocPriorityTable, 343allocPriorityThreshold, 344allocPriorityTimers, 345allocWaitThreshold, 346allOtherCasesPriority, 346amrAdaptationSet, 426, 427, 428

amrDirectAllocIntRxLevDL, 436amrDirectAllocIntRxLevUL, 436amrDirectAllocRxLevDL, 435amrDirectAllocRxLevUL, 435amrFRIntercellCodecMThresh, 436amrFRIntracellCodecMThresh, 437amrHRIntercellCodecMThresh, 437amrHRtoFRIntracellCodecMThresh, 437amriRxLevDLH, 438amriRxLevULH, 438amrReserved1, 439amrReserved2, 439answerPagingPriority, 347

assignRequestPriority, 347averagingPeriod, 372baseColourCode, 447bCCHFrequency_adjacentCellHandover, 398bCCHFrequency_adjacentCellReselection, 398bCCHFrequency_bts, 400biZonePowerOffset_adjacentCellHandover, 362biZonePowerOffset_handoverControl, 363bscHopReconfUse, 388bscMSAccessClassBarringFunction, 348bscQueueingOption, 348bsMsmtProcessingMode, 335bsPowerControl, 335bssMapT1, 376bssMapT12, 376bssMapT13, 376bssMapT19, 377bssMapT20, 377bssMapT4, 377bssMapT7, 378bssMapT8, 378bssMapTchoke, 378bssPagingCoordination, 448bssSccpConnEst, 379bsTxPwrMax, 335bts Time Between HO configuration, 309btsHopReconfRestart, 388btsIsHopping, 389

btsMSAccessClassBarringFunction, 349btsSMSynchroMode, 446btsThresholdHopReconf, 389callClearing, 331callReestablishment, 297callReestablishmentPriority, 349capacityTimeRejection, 415cellAllocation, 390cellBarQualify, 350

cellBarred, 350cellDeletionCount, 305cellDtxDownLink, 403cellReselectHysteresis, 284cellReselectOffset, 285cellReselInd, 285cellType_adjacentCellHandover, 329cellType_bts, 329channelType, 350cId, 418coderPoolConfiguration, 430compressedModeUTRAN, 418concentAlgoExtMsRange, 364

concentAlgoExtRxLev, 365concentAlgoIntMsRange, 364concentAlgoIntRxLev, 366, 367concentric cell, 368cypherModeReject, 449dARPPh1Priority, 447data mode 14.4 kbit/s, 404data non transparent mode_bts, 404data non transparent mode_signalingPoint, 404data transparent mode_bts, 405data transparent mode_signalingPoint, 405Data14_4OnNoHoppingTs, 404delayBetweenRetrans, 383directedRetry, 358directedRetryModeUsed, 359directedRetryPrio, 353distHreqt, 307distWtsList, 307diversity, 407diversityUTRAN, 418dtxMode, 403early classmark sending, 396earlyClassmarkSendingUTRAN, 419emergencyCallPriority, 351enableRepeatedFacchF, 443encrypAlgoAssComp, 450encrypAlgoCiphModComp, 450encrypAlgoHoPerf, 450




encrypAlgoHoReq, 451encryptionAlgorSupported, 451enhancedTRAUFrameIndication, 409enhCellTieringConfiguration, 410estimatedSiteLoad, 395

extended cell, 331facchPowerOffset, 443fDDARFCN, 419fDDMultiratReporting, 293fDDreportingThreshold, 293fDDreportingThreshold2, 294fhsRef, 391fnOffset, 446forced handover algo, 309frAMRPriority, 432

intraCell, 322intraCellHOIntPriority, 352intraCellQueueing, 353intraCellSDCCH, 322layer3MsgCyphModeComp, 452

locationAreaCodeUTRAN, 423lRxLevDLH, 325lRxLevDLP, 336lRxLevULH, 325lRxLevULP, 336lRxQualDLH, 327lRxQualDLP, 337lRxQualULH, 327lRxQualULP, 337maio, 392

V18 BSS Parameter Guide

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Transcript of V18 BSS Parameter Guide