GSM Optimization Handbook

Radio Network Optimisation Handbook

GSM OPTIMIZATION

HANDBOOK

1.Introduction32.Support Arrangement43.Optimisation Team Structure54.Bad Perfromance FisH Bone diagram65.Information Preparation76.General Optimisation Proceedure87.Alarm Analysis98.Statistics Investigation Procedure109.Drive Test129.1.Drive Test Reminder129.2.Drive Test Log Investigation Consideration1210.Frequeny Planning1310.1.BCCH and BSIC planning criteria1310.2.Frequency Assignment Criteria1310.3.Frequency Retune Procedure1411.Add Neighbor Criteria1412.High Rise Building Coverage1513.Maximum System Configuration1514.HDPC Setting Template1714.1.TX Power and Power Control1714.2.Handover2014.3.Multiband2214.4.Miscellaneous2215.Tools Available2416.Problem Root Cause2516.1.High SDCCH Blocking2516.2.High TCH Blocking2616.3.SDCCH Access Failure Rate2716.4.Handover Failure & Loss2816.5.MSC Connection Rate 2916.5.SDCCH and TCH RF Loss3016.6.Power Control3116.7.Handover Problem3116.8.Others32

1. Introduction

Teamwork, listen to order, cycle time reduction and follow procedure are critical to every successful optimisation.

Below is the optimisation flow chart:

2. Support Arrangement

3. Optimisation Team Structure

Job Function

BSS Controller

- Understand fully on BTS maintenance, BSS configuration

Alarm Monitoring,

- Monitor daily alarm

Statistics Monitoring

- Investigate problem from statistics

D.B. & Feature Controller

- Check database and monitor feature deployment process

Drive Test Log Investigator

- Investigate problem from drive test log

4. Bad Perfromance FisH Bone diagram

Example of each major problems:

a. Database Setting improper HOPC settings

b. Neighbor wrong external neighbors BCCH or BSIC values, missing neighbor

c. Coverage weak, highly overlapped, improper antenna downtilt and orientation

d. External Interference microwave, repeater, faulty alarm

e. Calculation incorrect statistics equations

f. Cable Connection no/cross connection

g. Statistics Pegging and Collection SW problem on statistics pegging, or retrieval

h. Capacity lack of TRCU, improper channel configuration, lack of RSL, MTL links

i. Frequency Plan co-channel, adj-channel, improper BSIC planning

j. Software bug

k. Hardware wrong cable connection, faulty combiner and filter, PCM link down

l. Network Topology bad site location selection, redundant site deployed

m. Signaling Improper cause value and message sequence

n. Mobile faulty mobile in term of signaling or frequency hopping capability

o. Documentation wrong feature/parameter usage description

5. Information Preparation

6. General Optimisation Proceedure

7. Alarm Analysis

Below lists some important alarms that we focus,

a. Critical and major alarm

b. Alarms affect voice quality like MSI, KSW, RXCDR, DRIM, DRI

c. GCLK affects HO

d. Link alarms affect site availability and voice quality

e. XBL alarm affects acknowledgement of OOS CIC

8. Statistics Analysis Procedure

Statistics Tree Diagram

Firstly, we need to understand account teams and customer performance equation.

Problem Identification from Statistics

1. per carrier on HW, external interference, channel interference, coverage

a. PATH_BALANCE for faulty hardware (Every 3 days)b. IOI for external interference and bad channel assignment (Every Day)c. BER for external interference and bad channel assignment (Every Day)d. TCH_RF_LOSS for faulty hardware and bad channel assignment (Every Day)e. CHAN_REQ_FAIL_ROLL for faulty hardware and BCCH and SDCCH coverage footprint difference (Every Day)2. per cell on usage

a. AVAILABLE_TCH and AVAILABLE_SDCCH (Every Day)b. BUSY_SDCCH_MAX, SDCCH Blocking for faulty hardware (Every Day)c. SDCCH_CONGESTION and BUSY_SDCCH_MEAN for phantom RACH (Weekly)d. BUSY_TCH_MAX, TCH Blocking for faulty hardware (Every Day)e. OK_ACC_PROC_SUC_RACH for sleeping cell (Every Day)f. No TOTAL_CALL, OUT_INTRA_BSS_ATMPT, OUT_INTER_BSS_ATMPT (Every Day)g. CONN_REFUSED { - IMSI_DETACH} for CIC blocking (Weekly)h. cell without any statistics for OOS cell (Every Day)3. per cell on dual band mobile usage

a. MA_ACCESS_BY_TYPE (Weekly)b. MS_TCH_USAGE_BY_TYPE (Weekly)4. per cell on Cipher Mode

a. CIPHER_MODE_FAIL (Weekly)5. per cell on loading

a. BSS GPROC loading mean 70% (Weekly)b. MSC Processor Loading and Subscriber (Weekly)c. RSL TX, RX Utilisation mean 25% (Weekly)d. MTL TX, RX Utilisation mean 20% (Weekly)e. Pages per second (Weekly)

f. ALLOC_SDCCH, ALLOC_SDCCH_FAIL ,OK_ACC_PROC relationship (Weekly)g. HO per call (Weekly)6. per cell on paging

a. PCH_PAGE_Q_DISCARD (Weekly)7. per cell for BCCH and BSIC planning

a. INV_EST_CAUSE_RACH and BAD_HO_REFNUM_MS (Weekly)8. per cell inter-BSS HO monitoring

a. OUT_INTER_BSS_MS_FAIL + OUT_INTER_BSS_MS_LOST = HP_MSC_REQ_FAIL (not include blocking) (Weekly)b. OUT_INTER_BSS_MS_ATMPT = HO_MSC_REQ_FAIL + HO_MSC_REQ_OK (Weekly)Below all are daily task:

9. evaluate target

a. calculate system total call, total loss, ho loss, rf loss, drop call%

b. calculate how many total loss reduction is required to achieve the goal

c. do (b) again for other statistics

10. select worst cells and BSCs

d. pick worst 20 cells and worst 5 BSCs

11. per cell on TCH Assignment

a. CONN_REQ_TO_MSC

b. MA_REQ_FROM_MSC, CONN_REFUSED { - IMSI_DETACH}, if CONN_REFUSED is high, MSC procedure is required.

c. MA_CMD_TO_MS_BLKD, MA_CMD_TO_MS

d. MA_FAIL_FROM_MS, MA_COMPLETE_TO_MSC (same as TOTAL_CALL)

12. per cell on HO Cause

a. OUT_HO_CAUSE

13. per cell on HO Failure

a. OUT_INTRA_BSS_HO_FAIL, OUT_INTER_BSS_HO_FAIL, IN_INTRA_BSS_HO_FAIL and IN_INTER_BSS_MS_NO_SEIZE for ho failues

14. per cell on TCH_RF_LOSS, SD_RF_LOSS, HO Loss

a. TCH_RF_LOSS, OUT_INTRA_BSS_HO_REQ, OUT_INTRA_BSS_HO_ATMPT, OUT_INTER_BSS_HO_REQ, OUT_INTER_BSS_HO_ATMPT

b. SD_RF_LOSS and HO_LOSS relationship on cell coverage

c. OUT_INTER_BSS_HO_LOSTMS, OUT_INTRA_BSS_HO_LOSTMS, OUT_INTRA_CELL_HO_LOSTMS

For hardware fix, it usually takes 3 days to fix, hence we suggest to review those statistics every 3 days. For system loading and usage, we will visit them once in a week.

Weekly and every 3 days statistics should be reviewed when that corrective action is done.

Special Request

For growth planning per cell on blocked call setup, we can use ALLOC_TCH_FAIL HO_FAIL_NO_RESUORCES_INTRA_BSS - HO_FAIL_NO_RESUORCES_INTER_BSS - HO_FAIL_NO_RESUORCES_INTRA_CELL to estimate expanded network total calls.

For coverage analysis and improve MSC connection rate, we can use per LAC ACCESS_PER_RACH PAGING_RESPONSE. Difference tells us how many no page reponses.

9. Drive Test

9.1. Drive Test Reminder

i. prepare cell definition file

ii. 2mins per call

iii. 10-15mins per log file

iv. force to appropriate band (GSM only, DCS only or Dual)

v. mark benchmark route per log file in map

vi. mark on maps about (a) drop call (b) weak coverage (c) lot of rxquality (d) bad coverage

vii. fill in drive test problem sheet

9.2. Drive Test Log Investigation Consideration

General TEMS Log Investigation Concern

1. check undecoded BCCH this affects RF loss and creates log of ping pong handover

2. decoded neighbor but no handover is attempted due to missing neighbor or incorrect external neighbor path

3. focus on drop call and rxqual greater than 4 for non-hopping, 5 for hopping for at least 4 seconds

4. look for handover failure investigation target cell assigned ARFCN/MA from ASSIGNMENT COMMAND and HANDOVER COMMAND

5. mark down weak coverage area, no dominant server, say less than 85dBm

6. mark down highly overlapped area

Besides, be careful that when you see a decoded cell, that cell is not definitely a neighbor of serving, it can be due to serving cell having a neighbor which has same BCCH as decoded cell.

Note: (a) Focus on new site database

(b) Due to CCB, no SFH can be deployed

(c) Dedicated ARFCN/MA is different from BCCH

(d) After Assignment and Handover, the cell ID may not be updated yet due to serious rxquality at DL.

10. Frequeny Planning

10.1. BCCH and BSIC planning criteria

a. Cells have same BCCH and BSIC that increases TEMS log review troublesome.

b. Nearby cells have same BCCH:BSIC with ARFCN:BSIC.

c. Nearby cells have adjacent BCCH with ARFCN and same BSIC.

10.2. Frequency Assignment Criteria

Non-hopping Case

Hopping Case for non-BCCH

BCCH in hopping case is same as the non-hopping case.

10.3. Frequency Retune Procedure

Frequencies can be grouped into 5 types, they are:-

a. same site co- and adj-channel to BCCH

b. adjacent site co- and adj-channel to BCCH

c. adjacent site co-channel to ARFCN

d. same site co-channel to ARFCN

e. same site adj-channel to ARFCN

f. adjacent site adj-channel to ARFCN

g. others ARFCN

Priority of ARFCN retune is from g. to e. for fix and BBH, from g. to d. for SFH. If no available ARFCN can be found, site planning need to be reviewed.

Besides, 400k separation is required for CCB.

58, 70 shouldnt be used for BCCH.

MCell generates UL interference on channel 50 and 56.

11. Add Neighbor Criteria

In general, LOS and 2nd Round Interferer will be added as neighbor; however, for 3rd Round, this is very network dependant. field knowledge is required to make the decision.

12. High Rise Building Coverage

Introduce high rise building coverage must make sure to have good street coverage.

High Rise Building provide high level (likely above 8th floor) high rise building coverage

Macro provide low floors and street level coverage

Micro provide street level and indoor coverage

13. Maximum System Configuration

It is important to understand how system grows from phase to phase. It can be described in 3 phases.

Phase 1: Only macro layer, antenna located at tower top with small downtilt. Antenna uses large vertical beam-width.

Phase 2: Start to introduce micro layer, and increase macro cell downtilt and lower macro cell height of macro antenna.

Phase 3: Introduce high rise building coverage to office building and hotel. Before deploying this kind of coverage, street level coverage MUST be strong enough (likely more than 75dBm) to protect interference from high rise building coverage.

For a mature network which its system rxlevel has reach average 75dBm, it is time for us to deploy SFH to expand system capacity.

14. HDPC Setting Template

14.1. TX Power and Power Control

TX Power

ParameterCurrent

SettingSuggest SettingReason

max_tx_ms

max_tx_bts

Downlink Power Control due to Level

ParameterCurrent


decision_alg_num

bts_power_control_allowed

bts_p_con_ack (TIMER)

bts_p_con_interval (TIMER)

pow_inc_step_size

pow_red_step_size

rxlev_dl_pc, hreqave

rxlev_dl_pc, hreqt

decision_1_dl_rxlev_av_p

l_rxlev_dl_p

u_rxlev_dl_p

decision_1_n1

decision_1_p1

decision_1_n2

decision_1_p2

Downlink Power Control due to Quality

ParameterCurrent


decision_alg_num

bts_power_control_allowed

bts_p_con_ack (TIMER)

bts_p_con_interval (TIMER)

pow_inc_step_size

pow_red_step_size

rxqual_dl_pc, hreqave

rxqual_dl_pc, hreqt

rxqual_dl_pc, qual_weight

decision_1_dl_rxqual_av_p

l_rxqual_dl_p

u_rxqual_dl_p

decision_1_n3

decision_1_p3

decision_1_n4

decision_1_p4

w_qual

Uplink Power Control due to Level

ParameterCurrent


decision_alg_num

ms_power_control_allowed

ms_p_con_ack

ms_p_con_interval

pow_inc_step_size

pow_red_step_size

rxlev_ul_pc, hreqave

rxlev_ul_pc, hreqt

decision_1_ul_rxlev_av_p

l_rxlev_ul_p

u_rxlev_ul_p

decision_1_n1

decision_1_p1

decision_1_n2

decision_1_p2

Uplink Power Control due to Quality

ParameterCurrent


decision_alg_num

ms_power_control_allowed

ms_p_con_ack

ms_p_con_interval

pow_inc_step_size

pow_red_step_size

rxqual_ul_pc, hreqave

rxqual_ul_pc, hreqt

rxqual_ul_pc, qual_weight

decision_1_ul_rxqual_av_p

l_rxqual_ul_p

u_rxqual_ul_p

decision_1_n3

decision_1_p3

decision_1_n4

decision_1_p4

w_qual

Data and Hopping Quality Power Control

ParameterCurrent


data_qual_flag

l_rxqual_dl_p_data

l_rxqual_ul_p_data

hop_qual_enabled

l_rxqual_dl_p_hopping

l_rxqual_ul_p_hopping

Standard MS HO Power, MS Ho Power Level based on Path Loss Calculations (GSR3)

ParameterCurrent


handover_power_level

use_derived_ho_power01Reduce MS UL power and interference

Optimised Power Control (GSR4)

ParameterCurrent


dyn_step_adj

dyn_step_adj_fmpr

pow_inc_step_size_dl

pow_inc_step_size_ul

pow_red_step_size_dl

pow_red_step_size_ul

Oscillation Prevention for MS Power Control

ParameterCurrent


mspwr_alg

Rapid MS Power Down

ParameterCurrent


rpd_pwr_down

rpd_period (TIMER)

rpd_trigger

rpd_offset

14.2. Handover

Inter-cell HandoverParameterCurrent


inter_cell_handover_allowed

Intra-cell Handover

ParameterCurrent


intra_cell_handover_allowed

ho_ack (TIMER)

hop_count

hop_count_ timer

Uplink Quality

ParameterCurrent


ul_rxqual_ho_allowed

rxqual_ul_ho, hreqave

rxqual_ul_ho, hreqt

rxqual_ul_ho, qual_weight

rxqual_ul_ho, qual_pwr_flag

rxqual_ul_ho, qual_margin

rxqual_ul_ho, adj_qual_margin

decision_1_ul_rxqual_av_h

l_rxqual_ul_h

u_rxqual_ul_h

decision_1_n6

decision_1_p6

w_qual

Uplink Interference

ParameterCurrent


interfer_ho_allowed

rxlev_ul_ho, hreqave

rxlev_ul_ho, hreqt

rxlev_ul_ho, qual_margin

rxlev_ul_ho, adj_qual_margin

decision_1_ul_rxlev_av_ih

u_rxlev_ul_ih

decision_1_n7

decision_1_p7

Downlink Quality

ParameterCurrent


dl_rxqual_ho_allowed

rxqual_dl_ho, hreqave

rxqual_dl_ho, hreqt

rxqual_dl_ho, qual_weight

rxqual_dl_ho, qual_pwr_flag

rxqual_dl_ho, qual_margin

rxqual_dl_ho, adj_qual_margin

decision_1_dl_rxqual_av_h

l_rxqual_dl_h

u_rxqual_dl_h

decision_1_n6

decision_1_p6

w_qual

Downlink Interference

ParameterCurrent


interfer_ho_allowed

rxlev_dl_ho, hreqave

rxlev_dl_ho, hreqt

rxlev_dl_ho, qual_margin

rxlev_dl_ho, adj_qual_margin

decision_1_dl_rxlev_av_ih

u_rxlev_dl_ih

decision_1_n7

decision_1_p7

Uplink Level

ParameterCurrent


ul_rxlev_ho_allowed

rxlev_ul_ho, hreqave

rxlev_ul_ho, hreqt

decision_1_ul_rxlev_av_h

l_rxlev_ul_h

u_rxlev_ul_h

deicion_1_n5

decision_1_p5

Downlink Level

ParameterCurrent


dl_rxlev_ho_allowed


rxlev_dl_ho, hreqt

decision_1_dl_rxlev_av_h

l_rxlev_dl_h

u_rxlev_dl_h

decision_1_n5

decision_1_p5

Distance

ParameterCurrent


ms_distance_allowed

rel_tim_adv, hreqave

rel_tim_adv, hreqt

decision_1_tim_adv_av_alg

ms_max_range

decision_1_n8

decision_1_p8

poor_initial_assignment

timing_advance_period (TIMER)Define the interval between timing advance changes

Power Budget

ParameterCurrent


pwr_handover_allowed


rxlev_dl_ho, hreqt

surround_cell, hreqave

decision_1_pbgt_rxlev_av_h

decision_1_ncell_rxlev_av_h_calc

max_tx_ms (serving cell)

ms_tx_pwr_max_def (internal neighbor default)

ms_tx_pwr_max_cell (external neighbor)

use_neighbor_pbgt_hreqave1

Data and Hopping Quality Handover Control

ParameterCurrent


data_qual_flag

l_rxqual_dl_h_data

l_rxqual_ul_h_data

hop_qual_enabled

l_rxqual_dl_h_hopping

l_rxqual_ul_h_hopping

14.3. Multiband

Multiband Handover

ParameterCurrent


mb_preference

phase2_classmark_ allowed

early_classmark_sending

early_classmark_delay

interband_ho_allowed

band_preference

band_preference_mode

multiband_reporting

14.4. Miscellaneous

Criteria 1

ParameterCurrent


rxlev_min_def5rxlev_min_def (internal neighbor default)

rxlev_min_cell5rxlev_min_cell (external neighbor)

Criteria 2

ParameterCurrent


ho_margin_def4,5

Neighboring Cell Processing

ParameterCurrent


ncell_pro0

disuse_cnt_hreqave0

ho_only_max_pwr1

neighbor_journal0

worse_neighbor_ho0

Alternative Processing of Rxqual Measurements

ParameterCurrent


alt_qual_proc00Quality Band Unit

Broadcast Control Channel Allocation (BA) Reinitialization

ParameterCurrent


ba_alloac_proc1

Missing ReportParameterCurrent


missing_rpt00Waiting for the actual data

Handover Timer

ParameterCurrent


handover_recongnized_period

bssmap_t7

Link Disconnection

ParameterCurrent


radio_link_timeout

rr_t3109

link_about_to_fail

link_fail

full_pwr_rfloss

15. Tools Available

COP Event Counting Tool, Call Trace Product, Generic Look Up, Cell Analysis Tool 2

TEMS and Safco

K1103

Web Statisitcs

NetPlan

BSS Database

GEP

16. Problem Root Cause

16.1. High SDCCH Blocking

16.2. High TCH Blocking

16.3. SDCCH Access Failure Rate

Note: SDCCH blocking is excluded.

16.4. Handover Failure & Loss

MSC Connection Rate

16.5. SDCCH and TCH RF Loss

16.6. Power Control

Sudden Power Drop

1. Incorrect call clearing timer setting

2. Faulty hardware

Slow Power Control

1. ho_only_max_pwr is turned on

2. Bad xx_p_con_ack and xx_p_con_interval

Power Control Window

1. Any external interference

2. Frequency planning technique

3. Speed of power down and up

4. Street or indoor coverage

16.7. Handover Problem

Ping Pong Handover

1. Bad radio calibration

2. Hardware fault

3. Negative handover allowed

4. Quality handover without turning on qual_pwr flag

5. Especially air combing, one of TX, RX antenna is blocked by building

Negative Handover

1. Neighbor journal

2. qual_margin_flag=0

3. Bad radio calibration between BCCH and non-BCCH

4. Turn on ho_magrin_rxqual feature with default value

No and Delay Handover

1. Inappriorate hreqave, hreqt and N & P voting

2. Negative handover margin

3. Improper setting on handover_recognised_period and bssmap_t7

4. Improper HO algorithm (Type 4, 6)

5. Blocking

16.8. Others

Low Erlang Usage

1. Inappropriate C1, C2 and handover criteria

High Rxqual

1. Adjacent site interference

2. Same site MAIO assignment problem

3. High internal same site hit rate

4. External interference like cordless phone, alarm, BTS hardware

Undecode BSIC

1. GCLK shift

2. BCCH interfered

Spurious Coverage

1. Coverage optimization

2. TA control

Killed Paging

1. Too many access grant block reserved

2. Location area too large

No Paging After Mobile is on certain time period

1. MSC Location Update Timer < BSS Location Update Timer

No Call Setup

1. LACI is different between BSS and MSC

2. Cell BAR

Immediate Assignment Reject

1. NO SDCCH

Monthly performance meeting to identify optimisation targets.

Start optimisation

PEG discuss with account teams to identify optimisation targets.

Engineers perform brief audit in Beijing to understand REAL situation

Optimisation Flow

Contractor prepares optimisation information

in Beijing

9. Radio Calibration

PEG Arrangement

OMC Engineer arrives local office to setup data collection platform

8. HW (DRCU, Filter) Fault

6. Excessive TA

5. UL Interference

External check night line IOI

High cell site

High UL Path Loss

Co. or adj. channel interference

4. HW Problem, check per carrier chan_req_ms_fail stats. or check alarm

3. Link balance, DB power setting

2. Path Balance, BCCH is OK bat SD carrier not OK

1. Phantom RACH, check any same ARFCN and BSIC

LOW SDCCH ACCESS SUCCESS RATE

12. Inappropriate congestion HO setting

11. Increase of single or dualband MSs.

Y

N

N

Y

Y

N

Reduce ho margin and enable congestion relief

Site reconfiguration

8. check adjacent cell busy_tch_max, if the busy_tch_max-8>configured TCH

10. Add radio to cell without

adding new cabinet

9. Coverage hole and improper DT & orientation

Find neighbors which has high

in_intra_bss_ho_return in_inter_bss_ho_seize then

check its fp

7. If SD has no blocking. May reconfigure channels or enable channel reconfiguration feature

6. Check any co-located or close

micro-cell,see whether traffic

offload is possible by optismisig

DB

END

5. check out_intra_bss_no_return and out_inter_bss_ho_return, it is high

4. Long timer setting

intra_BSS HO_rrt3103

channel release_rrt3109

3. Its GCLK SHIFT causes neighbors bsic undecoded

2. Missing Neighbor or incorrect Neighbor BSIC

1. Any neighbors BCCH interfered

Find faulty TS From BER Stats or check alarm

BUSY_TCH_MAX

=MAX_CONFIGURED_TCH

HIGH TCH BLOCKING

Y

Y

Y

Y

N

N

N

N

Neighbors tx power reduced

No TCH BLOKING, ENABLE CHANNEL RE CONFIGUPATION

FP, Neighobr and Coverage

LAC BORDER REDESIGN check t3121

Network Topology

Database, Interference & Capacity

Capacity

Hardware

TEMS Log & FP. mainly on

Undecoded BCCH

Missing Neighbor

HO Failure

Incorrect External Neighbor

Weak Coverage

High Overlapping

use non-dominant server

by ARFCN retune, neighor change and coverage

Statistics & DB. mainly on

SDCCH Access Failure

CSFR

Drop Call

TCH_RF_Loss

HO_Loss

HO_Failure

by ARFCN retune, neighor change and coverage

Network Topology Problem due to no available ARFCN is found by:

Site Replacement

Coverage Optimisation

Capacity Dimensioning

Solve Blocking by:

BCCH Optimisation

Neighor Optimisation

Add Radio

Site Reconfiguration

Add Site

Antenna Refinement

Suggest Better Database Setting (Channel Reconfiguration, Standard HOPC, Blocking Timer , Congestion Relief)

Capture External Interference

Frequency Retune for high IOI, BER and TCH_RF_LOSS

Audit External Neighbor

Improper ARFCN:BSIC Planning

GPROC loading

RSL & MTL Usage

Hardware Fix (Sleeping Cell, OOS TCU, OOS TS

Path Balance Issue, Faulty TCU from TCH_RF_Loss Issue)

GCLK shift and frequent Phase Lock Loop failure from Alarm

Network Audit from

Alarm

Statistics

Database

Check customer statistics equations

Data Preparation & NetPlan Information Correction

Data Collection & Check Local Office NetPlan Information

Statistics Monitoring

Alarm Monitoring

Drive Test Log Investigator

D.B. & Feature Controller

Team Leader

2 days

2 days

2 days

12 days

1 day

Check neighbor in_intra_BSS_ho_return and in_inter_bss_ho_Seize, if high, Check neighbors fp

END

Is out_INTRA_BSS_HO_RETURN AND out_INTER_BSS_HO_RETURN A LOT?

END

Lot of location Update?

Coverage Hole

Neighbor Cell Outage or own cell carrier outage (l carrier can have max 2 SD)

Review OK_ACC_PROC like CM_SERVICE_REQ_CALL, PAGE_RESPONSE,LOCATION UPDATE

Missing Neighbor or incorrect neighbor DB Path, TOTAL_CALL/ALLOC_TCH may be used

Start optimisation and skill transfer and acquisition

Best engineering arrangement arrives at local office

All engineers return to Beijing to derive plan

PEG arrives local office to discuss the optimisation plan with Account Team and Customer

PEG derives optimisation plan

PEG audits network in Beijing

PEG prepares INFORMATION FOR OPTIMISTION

Account Team supplies required information

Check Neighbor BCCH being Interfered

May due to Phantom RACH and HO access burst, check any same ARFCN and BSIC

Path Imbalance (SDCCH not on BCCH carrier)

SD_MEAN_HOCDING TIME CONVERGES to T3101

Find faulty TS from BER stats or check alarm

Frequency

Plan

Software

Hardware

Capacity

Network Topology

Bad Performance

Calculation

External

Interference

Database

Setting

Coverage

Neighbor

Statistics Pegging and Retrieval

3rd Round Interferer

2nd Round Interferer

LOS interferer

serving cell

No

Yes

Satisfactory Result?

Data Collection

Optimisation

Complete

Data Preparation

Data Analysis

ACTION

serving cell

MONITORING

BSS Controller

2 days

2 days

BUSY_SD_MAX

=MAX CONFIGUREDSD

HIGH SD BLOCKING

co-channel

adjacent channel

adjacent

channel

co-channel

cant be co- or adj-cahannel

serving cell

6. Handover_power_level is max?

3. MSC Problem

7. HO failure

- Check target cell fp

5. HO Failure

- Incorrect External Neighbor Database

4. Bad fp or external Interference -find % of UL/DL Quality by out_ho_cause

2. Short rr_t3103

7. Proper setting on ms_txpwr_max_cch and ms_txpwr_max_def

8. MSC Connection Refused (MTL Congested)

6. Cipher Mode Fail

5. Infrequent Location Update

4. TCH BLOCKING

3. SD RF loss

2. Coverage Hole

1. Paging Overflow Causing Discard

Low MSC Connection Rate

Y

N

Check neighbor in_intra_bss_ho_return and in_inter_bss_ho_seize if high, check neighbor(s fp

END

9. Is out_intra_bss_ho_return

and out_inter_bss_ho_return

a lot?

8. Poor HDPC setting

7. SD RF LOSS

Inconsistent coverage

Not enough overlapping

No SDCCH HO

5. Coverage hole, check UL Path Loss

Missing Neighbor, usually by drive test or trace-call

Neighbor Blocking

-check (OUT_INTRA_BSS_HO_REQ_OUT_INTRA_BSS_HO_ATTEMPT)

or (OUT_INTER_BSS_REQ_TO_MSC_OUT_TNETER_BSS_HO_ATTEMPT)

and check neighbor(s ALLOC_TCH_FAIL

2. Hardware

(a)Path balance

-idea is 108;(120 (serious UL Path Loss)

;(100 (serious DL Path Loss)

(b)Radio

-check per carrier RF loss stats

(c) Neighbor cell outage

(d) GCLK SHIFT

a. Neighbors BCCH Interfered

b. External Interference

c. Use guard band

d. Use AMPS frequency

High SD & TCH RF LOSS

Micro

Macro

High Rise Building

9. Call clearing timer (t3109

GSM Optimization Handbook

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