WCDMA RNP Design Specifications for the Link Budget Tool-20050526-A-3.5

Product name Confidentiality level WCDMA RNP For internal use only Product version

V100R001 Total 40pages

WCDMA RNP

Design Specifications for the Link Budget Tool

(For internal use only)

Prepared by: URNP-SANA Date: 2002-08-17 Reviewed by: Date: Reviewed by: Date: Approved by: Date:

Huawei Technologies Co., Ltd. All Rights Reserved

WCDMA RNP Design Specifications for the Link Budget Tool

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2006-06-07 All Rights Reserved of 40

Revision Record

Date Revision version

Change Description Author

2002-08-17 1.00 Initial transmittal Wang Mingmin 2002-12-27 1.10 Upgrades sheet “Link Budget” to V3.10.

Modifications include: 1. Updates the link performance data based on the latest emulation data (12.16), including downlink & uplink demodulation performance and PC headroom. 2. Changes the background noise input method in the sheet to avoid associating the margin for background noise with the system noise performance, and sets the default value of the background noise at 2GHz to “-104dBm” based on the previous test reports. 3. The downlink interference margin used for the calculation of the downlink interference margin required can be queried from a table based on the cell radius, and the values are derived from [Mehta&Greenstein VTC'0]. 4. The coverage probability for outdoor subscribers is higher than that for indoor ones for lack of the penetration loss margin, and this factor has been taken into consideration in the setting of the coverage probability required. 5. The noise figure can be directly queried from a table so that the workload of updating the product specifications in the future can be reduced.

Wang Mingmin

2003-05-10 3.30 Upgrades sheet “Link Budget” to V3.30. Modifications include: 1. Changes the coupling loss calculation formula in the calculation of the downlink interference margin. The original formula is: “C38 + C13 + C33 - C14 - C18 + C19 + 1.4”=mean coupling loss on cell edge, while the changed formula is: “C38 + C13 + C33 - C14 - C18 + C19 + 1.4 + C36 - D37”

Wang Mingmin


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2003-05-10

3.30 Upgrades sheet “Link Budget” to V3.30. New features include: 1. Adds an “export link budget results” feature that makes it easy to refer to the link budget within a network planning document. 2. Adds an attached sheet “DL interference margin parameters” to make parameters “maximum output power of BS” and “adjacent-cell interference” therein configurable by user. 3. Adds a “no diversity” option to the uplink diversity configuration, which may be applicable to a highway scenario. 4. Increases the upper limit of the edge coverage probability in sheet “soft handover MultiCell gain” from 90% to 98%. 5. Hides the link performance data sheets “NodeB_Perf” and “UE_Perf” as well as macro codes to ensure information security.


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2003-05-10 3.30 Upgrades sheet “Link Budget” to V3.30. Modifications include: 1. Upgrades the link performance data based on

Treatise on WCDMA RNP Link Performance Data V1.0 provided by the Link Emulation Team.

2. Upgrades the noise figure settings based on the data provided by the RF Team.

3. Makes the “maximum output power of UE” as configurable by user, and sets its default value to “21dBm”. In the earlier version, the maximum output power of UE is set to “21dBm” in the case of a voice service and to “24dBm” in the case of a data service.

4. Changes the reference point for “sensitivity of receiver” from “TMA connector” to “cabinet top connector”.

5. Changes the default value of the background noise from “-104dBm” to “-200dBm”, which corresponds to an interference-free scenario, thus allowing us to compare our link budget results with other manufacturers’.

6. Changes the default value of the penetration loss required for outdoor coverage from 0dB to 8dB, which corresponds to the penetration loss required for in-vehicle coverage.

7. Associates C11 in sheet "Tools" with C34 in sheet “Link Budget" to synchronize the “stddev_of_slow_fading” with the current setting in the tool used to calculate the edge coverage probability.

8. Changes the typical value of C3 in sheet "Tools" from 0.8dB to 1.0dB to give consideration to the arrester loss.

9. Gives consideration to different methods in handling the downlink and uplink cable losses with TMA being used. The cable loss from cabinet-top connector to TMA connector is set by the user, while the loss from the TMA connector to antenna connector is defaulted to 0.7dB. For an uplink, the loss is used for the calculation of the NF at antenna connector. For a downlink, the loss plus the user-defined “cable loss” from cabinet-top connector to TMA connector is the total downlink cable loss.

10. Deletes the CS144 and C3384 bearer types for they are currently not supported by the product.

Wang Mingmin

2003-05-10 3.30 In addition to descriptions on the above modifications, this Design Specifications also include the following modifications: 1. Adds a description on the path loss

discrepancy involved in the calculation of the downlink interference margin, 1.4dB, caused by the difference between uplink and downlink frequencies.

Wang Mingmin


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2003-09-10 3.40 Upgrades sheet “Link Budget” to V3.40. Modifications include: 1. Updates the link performance data based on Treatise on WCDMA RNP Link Performance Data Version 2.10 provided by the Link Emulation Team. 2. Adds two multipath channel models, i.e. TU30 and RA250. 3. Gives consideration to the BLER, the default values of which are as follows: AMR12.2 1% CS64 0.1% PS64 5% PS144 5% PS384 5% 4. At present, the receiver performance is used as link performance. 5. Has removed the bug that causes an error in exporting link budget results. 6. Gives consideration to the downlink fast fading margin. 7. The fast fading margin will be set to 0 if it is a negative value. 8. The default values of parameters k1~k7 of model ASSET Standard MacroCell are derived from model Cost231-Hata.

Yang Shijie

2003-09-10 3.41 Upgrades sheet “Link Budget” to V3.40. Modifications include: 1. Adds a description on the “slant loss” of a cross polarization antenna in section Gain of BS Antenna. 2. Has removed the bug that the link budget tool in use would function improperly and need refreshing if another Excel file is opened. 3. Updates the SHO over slow fading table and expands the edge coverage probability range to “2%-98%”.

Yang Shijie

2003-10-29 3.42 Upgrades sheet “Link Budget” to V3.42. Modifications include: 1. The maximum output power of UE is set to “21dBm” in the case of a service at a rate lower than 64kbps, or to “24dBm” in the case of a service at 64kbps or a higher rate.

Yang Shijie

2003-12-11 3.50 Upgrades sheet “Link Budget” to V3.42. Modifications include: 1. Updates the noise figure settings with and without TMA being used, based on the product specifications. 2. Changes the default parameters of model Asset based on the suggestions of Wang Shengyou. 3. The path loss factor in sheet “Tools” is calculated based on the propagation model selected.

Yang Shijie


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Table of Contents

1 Overview...................................................................................................................................................10 1.1 Objective ..............................................................................................................................................10 1.2 Scope ...................................................................................................................................................10

2 Implementation Technology .....................................................................................................................10 3 Parameter Settings.....................................................................................................................................10 3.1 Scenarios .............................................................................................................................................10

3.1.1 Morphology ............................................................................................................................10 3.1.2 Channel model ......................................................................................................................11 3.1.3 Sectorise ................................................................................................................................11 3.1.4 Bearer Type ...........................................................................................................................11 3.1.5 Diversity Configuration ..............................................................................................................12 3.1.6 TMA (Tower Mounted Amplifier) ........................................................................................12 3.1.7 Indoor Coverage ........................................................................................................................12

3.2 Max Power of TCH.............................................................................................................................13 3.2.1 Maximum Output Power of Uplink TCH ............................................................................13 3.2.2 Maximum Output Power of Downlink TCH .......................................................................13

3.3 Cable Loss...........................................................................................................................................13 3.3.1 Cable Loss without TMA......................................................................................................14 3.3.2 Cable Loss with TMA ...........................................................................................................14

3.4 Body Loss............................................................................................................................................14 3.5 Gain of Antenna ..................................................................................................................................14

3.5.1 Gain of UE Antenna .............................................................................................................14 3.5.2 Gain of BS Antenna..............................................................................................................14

3.6 EiRP ....................................................................................................................................................15 3.7 NF (Noise Figure) ...............................................................................................................................15

3.7.1 NF of UE Receiver................................................................................................................15 3.7.2 NF of BS Receiver ................................................................................................................15

3.8 EbvsNo Required ................................................................................................................................16 3.8.1 Demodulation performance of UE......................................................................................16 3.8.2 Demodulation performance of BS ......................................................................................16

3.9 Sensitivity of Receiver ........................................................................................................................16 3.10 Cell Loading ..................................................................................................................................16

3.10.1 Uplink Cell Loading .................................................................................................................16 3.10.2 Downlink Cell Loading ............................................................................................................17

3.11 Interference Margin .......................................................................................................................17 3.11.1 Uplink interference margin .....................................................................................................17 3.11.2 Downlink interference margin ................................................................................................17

3.12 Margin for Background Noise .......................................................................................................19 3.13 Fast Fading Margin........................................................................................................................19

3.13.1 Uplink Fast Power Control Headroom ...................................................................20 3.13.2 Downlink Fast Power Control Headroom ..............................................................21

3.14 Minimum Signal Strength Required ..............................................................................................21 3.15 Penetration Loss ................................................................................................................................21 3.16 Slow Fading Margin ......................................................................................................................22

3.16.1 Uplink Slow Fading Margin Required ...................................................................................22 3.16.2 Downlink Slow Fading Margin ...............................................................................................24

3.17 SHO Gain.......................................................................................................................................25 3.17.1 Uplink MultiCell Gain...............................................................................................................25 3.17.2 Uplink MDC Gain .....................................................................................................................28 3.17.3 Downlink MultiCell Gain..........................................................................................................29 3.17.4 Downlink MDC Gain ................................................................................................................29

3.18 Path Loss........................................................................................................................................29 3.19 Propagation Model ............................................................................................................................30

4 Definitions of Functions............................................................................................................................30


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4.1 Calculation of the Area Coverage Probability.....................................................................................30 4.1.1 Function Name......................................................................................................................30 4.1.2 Purpose ..................................................................................................................................30 4.1.3 Input Parameters .......................................................................................................................31 4.1.4 Returned Value .....................................................................................................................31 4.1.5 Implementation......................................................................................................................31 4.1.6 Functions Called ...................................................................................................................31

4.2 Calculation of the Slow Fading Margin...............................................................................................32 4.2.1 Function Name......................................................................................................................32 4.2.2 Purpose ..................................................................................................................................32 4.2.3 Input Parameters ..................................................................................................................32 4.2.4 Returned Value .....................................................................................................................32 4.2.5 Implementation......................................................................................................................32 4.2.6 Functions Called ...................................................................................................................32

4.3 Model COST231_HATA ....................................................................................................................32 4.3.1 Function Name......................................................................................................................33 4.3.2 Purpose .......................................................................................................................................33 4.3.3 Input Parameters ..................................................................................................................33 4.3.4 Returned Value .....................................................................................................................33 4.3.5 Implementation......................................................................................................................33 4.3.6 Functions Called ...................................................................................................................34

4.4 ASSET Standard MacroCell Model ....................................................................................................34 4.4.1 Function Name......................................................................................................................34 4.4.2 Purpose ..................................................................................................................................34 4.4.3 Input Parameters ..................................................................................................................34 4.4.4 Returned Value .....................................................................................................................34 4.4.5 Implementation......................................................................................................................35 4.4.6 Functions Called ...................................................................................................................35

5 Instructions for Use...................................................................................................................................35 5.1 Launch the Link Budget Tool .............................................................................................................35 5.2 Set the Scenario...................................................................................................................................36 5.3 Set-by-User Parameters .......................................................................................................................36

5.3.1 Maximum Output Power of Downlink TCH .......................................................................36 5.3.2 Cable Loss .............................................................................................................................36 5.3.3 Uplink/Downlink Cell Loading .............................................................................................37 5.3.4 Edge Coverage Probability Required .....................................................................................37 5.3.5 Base Station Height...................................................................................................................38 5.3.6 Downlink Frequency.............................................................................................................38 5.3.7 Parameters of ASSET Std. MacroCell Model...................................................................38

5.4 Export Link Budget Results ................................................................................................................38 5.5 Other Issues .........................................................................................................................................38

5.5.1 Existing Link Performance Data .........................................................................................38 5.5.2 OTSR Configuration .............................................................................................................39 5.5.3 Product & Auxiliary Equipment Performance and Version .............................................39


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List of Tables

table 1 UE power classes ....................................................................................................................13 table 2 Gain of Antenna ......................................................................................................................14 table 3 Relationship between cable loss and NF at TMA connector...................................................15 table 4 Relationship between non-orthogonality factor, cell radius and multipath channel model.....19 table 5 Mean penetration loss and standard deviation of indoor slow fading .....................................21 table 6 Relationship between edge coverage probability and slow fading margin .............................23 table 7 Relationship between area coverage probability and slow fading margin ..............................24 table 8 Relationship between SHO MultiCell gain, edge coverage probability and standard deviation

of slow fading............................................................................................................................................26 table 9 Typical values of the path loss factor in various morphologies ..............................................37

List of Figures

Figure 1 PC_HeadRoom vs. EbvsNo ....................................................................................................20 Figure 2 Outage probability curve in terms of distance of points in the SHO area ........................28 Figure 3 Meanings of cell background colors ..................................................................................36


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Key words: WCDMA, Link Budget

Abstract: This document introduces the parameter settings, implementation technology and

instructions for use of the Link Budget Tool V3.40.

List of abbreviations:

Abbreviation Full name Description


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1 Overview

1.1Objective As the Design Specifications for the Link Budget Tool V3.40, this document introduces the theory, implementation technology and instructions for use of the link budget tool.

1.2 Scope This document consists of the following parts: 1. Implementation Technology: Briefly introduces the technology used to implement

the link budget tool. 2. Parameter Settings: Describes in detail how to set each parameter and to what

value. 3. Custom Functions: Describes the custom functions in the link budget tool. 4. Instructions for Use: Explains issues that may be encountered during the use of

the link budget tool.

2 Implementation Technology

This version of link budget tool is implemented with Excel by using the following features of it: 1. Window control: Combo box, check box and grouping box. 2. Custom functions For details on how to use the tool, please refer to Help in Excel and section 5.

3 Parameter Settings

3.1 Scenarios

3.1.1 Morphology Target cell coverage areas are categorized into the following types: 1. Dense Urban 2. Urban 3. SubUrban 4. Rural Area 5. HighWay The morphology setting will affect the following parameters in sheet “Link Budget” (refer to sheet Scenarios): 1. Mean penetration loss, 2. Standard deviation of slow fading (stddev_of_slow_fading), 3. Propagation model and path loss factor. The following parameters should be set to appropriate values based on the morphology setting of the target area: 1. Channel model


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2. Sectorise 3. Indoor coverage 4. Basic services (services required to a ensure seamless coverage) 5. Configuration of the BS: TMA and diversity configuration 6. Cell loading 7. Height of BS antenna 8. Cable loss

3.1.2 Channel model According to recommendations in 3GPP R4 TR25.943 V4.0.0 (2001-06), this version of link budget tool provides the following typical channel models for selection: 1. Static: Static channel, non-multipath 2. TU3: Walk speed in typical urban area 3. TU50: Vehicle speed in typical urban area 4. TU120: High speed in typical urban area 5. RA120: High speed in rural area 6. RA250: High-speed in rural area 7. HT120: High speed in hilly terrain An appropriate multipath channel model should be selected. This setting will affect the following parameters in sheet “Link Budget”: 1. Link performance (EbvsNo required): Please refer to sheets EbvsNo (BS) and

EbvsNo (UE). 2. Uplink cell loading: Set to an appropriate value. 3. Downlink cell loading: Set to an appropriate value. 4. Downlink interference margin: Please refer to sheet “Senarios-non-othogonality

factor vs. multipath channel model”. 5. Fast PC margin. 6. Soft handover gain. Please refer to subsequent sections for details on these parameters.

3.1.3 Sectorise This version of link budget tool provides the following “Sectorise” settings for selection: 1. Omni 2. 3 Sector 3. 6 Sector This setting will affect the following parameters in sheet “Link Budget”: 1. Gain of antenna In addition, because the “Sectorise” setting will also affect the coverage area and soft handoverprobability, the following parameter should be set to an appropriate value as required:

1. Cell Loading

3.1.4 Bearer Type


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This version of link budget tool provides the following bearer types for selection: 1. Voice (12.2kbps) 2. CS64 3. CS144 4. CS384 5. PS64 6. PS144 7. PS384 This setting will affect the following parameters in sheet “Link Budget”: 1. Link performance (EbvsNo required): Please refer to sheets EbvsNo (BS) and

EbvsNo (UE). The major purpose of a link budget is to determine the cell coverage area and thereby determine the services required to ensure a seamless coverage (basic services). Hence, this parameter should be set based on the basic service requirement. Because the uplink and downlink traffics may be different due to the asymmetry attribute of a data service, the link budget tool provides controls used to set them separately.

3.1.5 Diversity Configuration All the diversity configurations described here refer to NodeB. Available uplink diversity configurations are as follows: 1. 2-antenna diversity 2. 4-antenna diversity 3. no Diversity (may be applicable to such scenarios as highways) Available downlink diversity configurations are as follows: 1. no Diversity 2. STTD 3. CloseLoop-Mode1 4. CloseLoop-Mode2 The Diversity Configuration setting will affect the following parameters in sheet “Link Budget”: 1. Link performance (EbvsNo required): Please refer to sheets NodeB_Perf and

UE_Perf.

3.1.6 TMA (Tower Mounted Amplifier) In a scenario with a high cable loss, TMA can be used to compensate for the deterioration of sensitivity of receiver due to the cable loss. This setting will affect the following parameters in sheet “Link Budget”:

1. Uplink NF of receiver (at antenna connector)

3.1.7 Indoor Coverage According tooperator’s requirements , decide whether to ensure indoor coverage or not. Please note that requirements for different target areas may be different.


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This setting will affect the following parameters in sheet “Link Budget”: 1. Penetration loss 2. std dev_of_slow_fading

3.2 Max Power of TCH

3.2.1 Maximum Output Power of Uplink TCH For a UE, the maximum output power of each TCH is the nominal maximum output power of UE. Though the RNC can use a signaling message to limit this maximum output power, it is usually set to the nominal maximum output power of UE in the link budget. Four UE power classes are defined in section 6.2.1 of TS 25.101 v3.7.0 (2001-06):

table 1 UE power classes Power Class Nominal maximum

output power Tolerance

1 +33 dBm +1/-3 dB

2 +27 dBm +1/-3 dB

3 +24 dBm +1/-3 dB

4 +21 dBm � 2 dB

In this version of link budget tool, this parameter should be set to “21dBm” in the case of a voice service or service at a rate lower than 64kbps, or to “24dBm” in the case of a service at 64kbps or a higher rate. During the actual network planning, the user should set this parameter based on the lowest UE power class used on the operator’s network.

3.2.2 Maximum Output Power of Downlink TCH The maximum output power of each downlink TCH is set by the RNC based on the service type. In this version of link budget tool, this parameter is configurable by user. The user should set this parameter to an appropriate value based on the service type, capacity requirement as well as uplink & downlink coverage balance requirement.

3.3 Cable Loss “Cable loss” refers to the cable loss of BS. The cable loss of UE is set to 0dB. "Tools-Cable Loss Estimation" can be used to estimate the cable loss. This setting will affect the following parameters in sheet “Link Budget”：

1. NF of uplink receiver (refer to section Noise Figure) 2. Downlink EiRP In this version of link budget tool: Without TMA, the “cable loss” is defined as between the cabinet-top connector and antenna connector. In this case, the downlink and uplink cable losses are identical with each other. With TMA being used, the “cable loss” is defined as between the cabinet-top connector and TMA connector. In this case, the uplink cable loss is used for the calculation of the NF at TMA connector, while the downlink cable loss is equal to the insertion loss of the duplex filter in the TMA plus the jumper loss between TMA and antenna connectors, the typical value of which is 0.7dB. Please refer to the following sections for details.


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3.3.1 Cable Loss without TMA Without TMA being used, the path from the cabinet-top connector to antenna connector consists of: 1. The segment from the cabinet-top connector to arrester; 2. Arrester; 3. The segment from the lightning arrester to feeder jumper; 4. The primary feeder; 5. The jumper from the feeder to antenna connector. The typical value of the loss at 2GHz over a 1/2" super-flexible jumper is 0.18dB/m. If the length of each jumper is 1.5m, the total jumper loss is about 0.8dB. The typical value of the arrester loss is 0.2dB. The primary cable loss depends upon the actual type and length.

3.3.2 Cable Loss with TMA With TMA being used, the cable loss from the cabinet-top connector to TMA connector is estimated in the same way as without TMA, except for that the jumper from the feeder to antenna connector becomes the jumper from the feeder to TMA connector. The loss from TMA connector to antenna connector consists of the insertion loss of the duplex filter in the TMA and the jumper loss from TMA connector to antenna connector. If the jumper length is 1.5m, the loss is about 0.3dB. The typical value of the insertion loss of the duplex filter in TMA is 0.4dB (uplink & downlink). For uplink, the loss from TMA connector to antenna connector is used for the calculation of the NF at antenna connector. For downlink, the loss plus the user-defined “cable loss” from cabinet-top connector to TMA connector is the total downlink cable loss.

3.4 Body Loss The body loss occurs on the UE side. The setting of this parameter depends upon how the UE is used. This version of link budget tool sets “body loss” by default to: 1. 3dB for voice service; 2. 0dB for data service, because data service is mainly for viewing,and UE is not

close to boby.

3.5 Gain of Antenna

3.5.1 Gain of UE Antenna Please refer to section 6.1 of 3GPP TS25.101 V2.7.0 (2001-06). We assume that the gain of UE antenna is 0dBi.

3.5.2 Gain of BS Antenna The “gain of BS antenna” should be set based on the specifications of the selected antenna. This version of link budget tool sets “gain of BS antenna” by default to:

table 2 Gain of Antenna


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In the case of a cross polarization antenna, because the radio wave arrives in a direction different from that of the antenna polarization, the actual gain is lower than the nominal gain. In the link budget tool of Ericsson and Nortel, this loss is reflected by a parameter called “slant loss” which is usually set to anywhere between 1 and 1.5dB. In our link budget tool, this loss is not an individual parameter but is included in the “gain of antenna”. Hence, the “gain of antenna” for an antenna with a nominal value of 18.5dBi (741794) will be set to 17dBi in the link budget tool.

3.6 EiRP EiRP is the abbreviation of Equivalent Isotropic Radiator Power. EiRP (dBm) = Max Power of TCH (dBm) - Cable Loss (dB) - Body Loss (dB) + Gain of Antenna (dBi)

3.7 NF (Noise Figure)

3.7.1 NF of UE Receiver In this version of link budget tool, the typical value of the “NF of UE receiver” is 7dB.

3.7.2 NF of BS Receiver To facilitate the calculation of NF with or without TMA being used, the reference point for the “NF of BS receiver” is defined as tower-top antenna connector.

3.7.2.1 Without TMA

Without TMA being used, the NF at tower-top antenna connector is equal to the cable loss from the cabinet top plus the NF at cabinet-top antenna connector. The NF at cabinet-top antenna connector was previously set to “2.92dB”, which applies to the most demanding environment. At present, it is set to 2.2dB, which is also used in the link budget tool. Hence, without TMA being used, the NF at tower-top antenna connector=NF_BS + cable loss.

3.7.2.2 With TMA

With TMA being used, to ensure a constant gain of uplink channel, the gain of NDDL should be set based on the actual cable loss to ensure that the gain of RF channel is about 38dB. When a TMA, the gain of which is 12dB, is used, the relationship between the cable loss calculated, gain of NDDL and NF at TMA connector is as shown in table below.

table 3 Relationship between cable loss and NF at TMA connector


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There is a 1/2’’ super-flexible jumper between the tower-top antenna connector and TMA. If its loss is assumed to be 0.3dB, the NF at tower-top connector is equal to the NF at TMA connector in the above table plus 0.3dB.

3.8 EbvsNo Required

3.8.1 Demodulation performance of UE The setting of this parameter is provided by the Link Simulation Team. The Link Budget Tool V3.40 corresponds to document Treatise on WCDMA RNP Link Performance Data Version 2.10.

3.8.2 Demodulation performance of BS The setting of this parameter is provided by the Link Simulation Team. The Link Budget Tool V3.40 corresponds to document Treatise on WCDMA RNP Link Performance Data Version 2.10.

3.9 Sensitivity of Receiver The “sensitivity of receiver” refers to the minimum signal strength determined by the background noise of the receiver. Sensitivity of Receiver_TOC (dBm) = -174 (dBm/Hz) + NF_TOC (dB) + 10lg[1000 * Rb (kHz)] + EbvsNo required (dB) To avoid different interpretations and keep it consistent with the published product specifications, the NF at cabinet-top connector rather than previously defined NF at antenna connector is used for the calculation of the sensitivity of receiver, accordingly, the sensitivity be defined at cabinet-top. In addition, please note that the “sensitivity of receiver” described here differs from the “reference sensitivity” described in section 7.2 of 3GPP TS25.104 V3.7.0 (2001-06) in:

1. Configuration: The “reference sensitivity” specified by the protocol is based on the testing of a single diversity channel, while the “sensitivity of receiver” in a link budget is a specification with the downlink diversity being used. 2. Channel model: The “reference sensitivity” specified by the protocol is measured using the “static channel” model, while the “sensitivity of receiver” in a link budget is calculated based on the demodulation performance using a multipath channel model.

3.10 Cell Loading

3.10.1 Uplink Cell Loading


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Definition:

UL = 1 − No/ITOT = 1 − 1NoiseRise

Formula 1

Assumption power control is perfect, the following formula is available:

UL = (1 + f)j=1

N 11 + 1

EbvsNo(j)WR(j)

1v(j)

Formula 2

The above formula can be used during the network planning to estimate the cell loading factor in a specified scenario.

3.10.2 Downlink Cell Loading The definition of the downlink cell loading in this version of link budget tool is as follows:

DL = PTX/Pmaxmaxmax Assumption power control is perfect, the following formula ([Dodoo Margin 1.10] formula 14) is available:

PTX =PCCH + No

n=1

N[SIR_Tx(n) CL(0,n)]

1 −n=1

NSIR_Tx(n) [ (n) + f(n)]

Formula 3

The above formula and analysis method in [Dodoo Margin 1.10] can be used to estimate the downlink cell loading.

3.11 Interference Margin

3.11.1 Uplink interference margin According to the definition about the uplink loading factor on formula 1, the uplink interference margin should be equal to the value of “NoiseRise” corresponding to the cell loading:

Formula 4

3.11.2 Downlink interference margin According to formula 19 [Dodoo Margin 1.10], obtained

Formula 5

Note: In the calculation of the interference margin, we use the “adjacent cell” definition in Best Server to calculate the downlink adjacent cell interference. Under the perfect soft handover condition, when the coupling loss from a UE to the adjacent cell is equal to that from it to this cell, the UE is located on the cell edge .

Uplink interference margin

( d B ) = N oiseRise(dB) = 10 llgg 11 − DL

Downlink interference margin

( d B ) = 1 0 llgg [ (j) + f(j)] ∃ DL_Ptx ∃ PmmmN0 ∃CL(0, j )

axaxax + 1

zeeshan

Text Box

Uplink Cell loading


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Because of the shadow fading, the coupling loss from the edge to Best Server may be greater or less than the mean coupling loss on cell edge calculated with the link budget. According to formal 5, the greater the coupling loss from the edge point to the serving cell, the less the downlink interference margin is required, but the gain of this link is less than the increase in the coupling loss. Hence, the maximum coupling loss at the edge point corresponds to the most demanding scenario for the link concerned, and this is the objective of link budget. Therefore, we should use the maximum coupling loss on cell edge to calculate the downlink interference margin required, and this coupling loss is defined as between the BS cabinet-top connector and UE receiver. Hence, the maximum uplink coupling loss as follows: CL_UL_max (dB) = Path Loss_max (dB) + Body Loss (dB) + Penetration Loss (dB) - Gain of Tx Antenna - Gain of Rx Antenna (dBi) + Cable Loss (dB) = mean_PathLoss_edge (dB) + Slow Fading Margin (dB) - SHO MultiCell Gain (dB) + Body Loss (dB) + Penetration Loss (dB) - Gain of Tx Antenna - Gain of Rx Antenna (dBi) + Cable Loss (dB) Note: Because the coupling loss is defined as between the BS cabinet-top connector and UE receiver, the “Cable Loss” in the above formula should be the total downlink cable loss from antenna connector to cabinet-top connector rather than the user-defined cable loss. For details, please refer to section 3.3. In the case of uplink coverage limited, the maximum downlink coupling loss is equal to the maximum uplink coupling loss plus the path loss discrepancy due to the difference in uplink and downlink frequencies. According to model COST231-HATA, Lu (dB) = 46.3 + 33.9*log(f) - 13.82*log(Hb) - a(Hm) +[44.9 - 6.55*log(Hb)]*log(d) + Cm. If the uplink frequency is 1950MHz and downlink frequency is 2140MHz, the path loss discrepancy due to the difference between them is around 1.4dB. Parameters related to the calculation of the downlink interference margin are listed in table Parameters of DL Interference Margin in sheet “Link Budget”.

According to the analysis in [Dodoo Margin 1.10], In formula 5, f(j) ‘s defaultvalue is 1.78 , and can be also set by the user base on actual cell conditions. The setting of a(j) is related to the assumptions of cell radius and multipath channel model, which can be queried in the link budget tool. Such as the following table 4:


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table 4 Relationship between non-orthogonality factor, cell radius and multipath channel model

3.12 Margin for Background Noise Because of external electromagnetic interference in some areas, we should reserve corresponding margin for background noise in the link budget. Suppose that the background noise of NodeB or UE is “X dBm”, and the external interference is “Y dBm”. The margin for background noise required is:

Margin for Background Noise = (X dBm + Y dBm) - X dBm This version of link budget tool sets the uplink and downlink background noises to -200dBm, which corresponds to 0dB margin for background noise required. During the actual network planning, user set the uplink and downlink background noises separatly according to the results of frequency cleaning test, the link budget tool use the above formula to calculate the interference margin required.

3.13 Fast Fading Margin The EbvsNo of receiver used in the link budget is the simulation result under the assumption of perfect power control. In a working system, because the transmitter power is limited, an non-ideal factor is introduced in the closed loop power control. Suppose the maximum output power of transmitter is TCH_max, under the power limited, within the special path loss, and the average output power of transmitter required to ensure the BLER/BER requirement is TCH_Average(PL). Defined the power control headroom as:

HeadRoom(r) = TCH_ − TCH_Average(r)

r

maxmaxmax And,

μ υ P L (r) μ υ H e a d R oom ο υ EbvsNo μυ υ r ο Sensitivity ο

[NOKIA 2002] Figure 4.23 shows the uplink simulation results obtained under a specified condition:


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Figure 1 PC_HeadRoom vs. EbvsNo

As shown in the above figure, when HeadRoom is very high, the target EbvsNo set by the outer loop power control is close to the simulation result under the perfect power control condition, namely, 4.8dB. EbvsNo increases as headroom decreases. After EbvsNo is greater than 7dB, it will increase nearly by 1dB each time when headroom decreases by 1dB. At the circle, as shown in the figure, which represents no power control, the BLER/BER required can no longer be ensured. What the link budget calculated is the cell edge and the maximum path loss allowed. In the above figure, the point where EbvsNo = 7dB (with the corresponding HeadRoom being about 4.7dB) is the cell edge point. Beyond this point,the outer loop power control couldn’t ensure the BLER/BER required, and the outage will occur. As the previously described, the EbvsNo required used in the link budget is the simulation result under the perfect power control, to ensure the maximum path loss calculated up to practical, we should set to the PC_HeadRoom to:

PC_HeadRoom = HeadRoom_Edge + (EbvsNo_Edge − EbvsNo_Ideal)

= (HeadRoom_Edge + EbvsNo_Edge) − EbvsNo_Ideal

(0dB+ EbvsNo_noPC) − EbvsNo_Ideal

= EbvsNo_noPC − EbvsNo_Ideal

Formula 6

Hence, Fast power control headroom can be set to the in the link budget to the EbvsNo required under no-power-control condition minus that under the perfect power control.

3.13.1 Uplink Fast Power Control Headroom


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The setting of this parameter is calculated based on the link performance data provided by the Link Simulation Team. The Link Budget Tool V3.40 corresponds to document Treatise on WCDMA RNP Link Performance Data Version 2.10.

3.13.2 Downlink Fast Power Control Headroom The setting of this parameter is calculated based on the link performance data provided by the Link Simulation Team. The Link Budget Tool V3.40 corresponds to document TREATISE ON WCDMA RNP Link Performance Data Version 2.10.

3.14 Minimum Signal Strength Required The minimum signal strength required to ensure the link performance can be calculated based on such factors as the static sensitivity of receiver, SHO gain and fast fading margin. In this version of link budget tool:

1. For uplink,

UL Minimum Signal Strength Required = Sensitivity of Receiver_TOC (dBm) + ( NF_Ant connector (dB) - NF_TOC (dB) ) - Gain of Antenna (dBi) + Body Loss (dB) + Interference Margin (dB) - SHO Gain over fast fading (dB) + Fast Fading Margin (dB)

2. For downlink:

DL Minimum Signal Strength Required = Sensitivity of Receiver (dBm) - Gain of Antenna (dBi) + Cable Loss (dB) + Body Loss (dB) + Interference Margin (dB) - SHO Gain over fast fading (dB) + Fast Fading Margin (dB)

3.15 Penetration Loss To ensure indoor coverage, we should include the penetration loss in the link budget. The penetration loss is related to such factors as the building type and incidence angel of the radio wave. Suppose that the penetration loss complies with the logarithmic normal distribution, the mean penetration loss(logarithmic value) and its standard deviation are used to describe the penetration loss. Because the types of buildings differ according to different areas, the morphology should be specified in the link budget tool. In this version of link budget tool, the standard deviation of penetration loss and that of path loss is combined into the standard deviation of indoor slow fading:

TOT = PathLoss2 + PenetrationLoss

2

Formula 7

Hence, to ensure indoor coverage, the slow fading margin and SHO gain should be calculated based on the standard deviation of indoor slow fading. In this version of link budget tool, typical values of mean penetration loss and standard deviation of indoor slow fading are listed in table below:

table 5 Mean penetration loss and standard deviation of indoor slow fading


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Network planning usually need toensure the communications quality for in-vehicle users. therefore, the penetration loss margin should be set 8dB for in-vehicle users rather than 0dB, even if outdoor coverage is our only concern.

3.16 Slow Fading Margin

3.16.1 Uplink Slow Fading Margin Required

3.16.1.1 Link Outage Probability

The link budget tool can calculate the minimum input signal level required, Smin, for the radio link of a UE at a specified location (d, )

_outage(d) =

. With a specified loading, Smin is determined by the demodulation performance of the link and has nothing to do with location. If the maximum output power of UE still cannot compensate for the path loss to ensure this Smin required, an outage will occur to the link. Hence, the link outage probability of a UE at d is:

PrPr PrPr P _UE − PL(d) < Smaxmaxmax minminmin

= PrPr P _UE − 10 (d) − < Smaxmaxmax lglg minminmin

= PrPr P _UE − S − 10 (d) <maxmaxmax minminmin lglg

= PrPr (r) <

Formula 8

wherein,

(r) = P _UE − S − 10 (d) = PL_ − 10 (d)maxmaxmax minminmin lglg maxmaxmax lglg , which means the maximum path loss allowed minus the mean path loss at d. To conform to the slow fading component in logarithmic normal distribution, the mean value of is 0 with its deviation being . 2

_outage(r) = 12

Hence,

PrPr(d)Exp − 2

2 2 d = Q

Formula 9

During the network construction, operators usually would specify a maximum outage probability requirement. From the above formula, we can easily conclude that the outage probability is in inverse proportion to . Because reaches its minimum value on cell edge, the probability reaches its maximum value there.

(r) (R)


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PrPr

When using the link budget tool to estimate the cell coverage, we should preserve the slow fading margin, , in addition to the maximum path loss calculated, to ensure the fulfillment of the maximum outage probability requirement.

= (R)

edge( , ) = 1 − _outage(R) = 1 − 12

3.16.1.2 Calculation of the uplink slow fading margin required with the edge coverage

probability required being specified

The relationship between edge coverage probability and slow fading margin is as follows:

PrPr Exp − 2

2 2 d ＝1 −Q = P

Formula 10

According to formula 10, the formula used to calculate the slow fading margin required to ensure a specified edge coverage probability is as follows:

= P−1( _edge_ )PrPr maxmaxmax Formula 11

Function NORMSINV in Excel can be used directly as the inverse function, P−1 , of the standard normal distribution cumulative function in the above formula. For details, please refer to Help in Excel. The table below is derived from formula 4:

table 6 Relationship between edge coverage probability and slow fading margin stddev_of_slow_fading

(dB) Slow fading margin (dB) Morphology

Outdoor Edge coverage probability required

75%

Edge coverage probability required

90%

Dense urban 10 6.74 12.82

Urban 8 5.40 10.25

Sub urban

6 4.05 7.69

Rural area 6 4.05 7.69

Highway 6 4.05 7.69

3.16.1.3 Calculation of the uplink slow fading margin required with the area coverage probability

required being specified

Sometimes, the vendor would specify an area coverage probability required rather than an edge coverage probability required. For example, “Available in over 95% part of the area and 99% of time”. The first part of this requirement, i.e. “Available in over 95% part of the area” is the area coverage probability requirement. According to the above descriptions, we have:

Rd(d) = + 10 lglg

The area coverage probability is the averaged coverage probability of all the points in the cell:


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0

1

0

2

Pedge + 10 ( 1rParea( , , ) = 1 lglg ), r dr d

= 12 1 − (a) + ( 1 − 2ab

b2 erferferf 1 − abberferferf expexpexp ) 1 −

Formula 12

wherein, ([Rappaport 1996]3.9.3),

a =2

b =102

(e)lglg

In this version of link budget tool, "Tools - Area Coverage Probability" can be used to establish the relationship between edge coverage probability and area coverage probability under specified standard deviation of slow fading and path loss factor. The “Tools” uses a single-variable function, GoalSeek

table 7 Relationship between area coverage probability and slow fading margin

stddev_of_slow_fading

(dB) Area coverage

probability required 90%

Area coverage probability required

95%

Morphology Path loss factor

Outdoor Slow fading margin

(dB)

Edge coverage probability

Slow fading margin

(dB)

Edge coverage probability

Dense urban

4.5 10 6.69 74.83% 10.77 85.93%

Urban 4.2 8 4.83 72.71% 8.21 79.41%

Sub urban

3.8 6 3.11 69.77% 5.70 71.56%

Rural area 3.3 6 3.50 72.01% 6.00 72.58%

Highway 3.3 6 3.50 72.01% 6.02 72.65%

3.16.2 Downlink Slow Fading Margin Unlike the uplink direction, in the downlink direction, the noise received by the UE receiver varies at each point, therefore the Smin required and maximum path loss allowed also varies at each point, and we have


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maxmaxmax minminmin

maxmaxmax

PL_ (d, ) = P_TCH_ − S (d, )

= P_TCH_ − No − Ioc(d, ) − Isc(d, ) [1 − (d, )]

maxmaxmax

Formula 13

3.16.2.1 Calculation of the downlink slow fading margin with the specified edge coverage

probability

If we can determine the settings of Isc, Ioc and orthogonality factor on the cell edge, namely, the setting of the downlink slow fading margin, we can determine the maximum path loss allowed on the cell edge, then use the same method as in the calculation of the uplink slow fading margin to calculate the slow fading margin required to ensure a specified edge coverage probability.

3.16.2.2 Calculation of the downlink slow fading margin with the specified area coverage

probability

Co-frequency adjacent-cell interference is the major interference on the cell edge. When the UE gets closer to the BS, the co-frequency adjacent–cell interference will decrease but the intra-cell interference will increase quickly. As a result, the sensitivity of UE will deteriorate quickly and the maximum path loss allowed will decrease. Because the presupposition for using formula 6 is that the maximum path loss allowed remains the same at any point in the cell as on the cell edge, if we still use this formula to estimate the area coverage probability based on the edge coverage probability area, we will overestimate the area coverage probability and therefore get a smaller slow fading margin. For the purpose of simplification, this version of link budget tool assumes that the downlink slow fading margin is equal to the uplink one. The error caused by this assumption is acceptable.

3.17 SHO Gain The SHO gain consists of the following two parts: 1. MultiCell gain: get from the decrease of the slow fading margin due to the existence of multiple SHO independent branches; 2. MDC (Macro Diversity Combining) gain: the link performance Gain because of soft handover.

3.17.1 Uplink MultiCell Gain Suppose that soft handover has 2-branches , and the dependency of the soft handover radio link branches on slow fading is 50%. We can calculate the slow fading margin required with soft handovers being involved based on this supposition, and compare it with the slow fading margin required without soft handover to get the SHO gain. In a real system, more than 2 branches may be involved in a soft handover, though this probability is pretty low, and the corresponding SHO gain is slightly higher than that of a 2-branch soft handover. Therefore, the SHO gain derived from the above supposition on 2-branch handovers is a relative conservative estimate value . Here below we will discuss how to calculate the MultiCell gain with the specified edge coverage probability and area coverage probability .


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PrPr

3.17.1.1 Calculation of the uplink SHO MultiCell gain with the edge coverage probability


On the cell edge, if no soft handover is involved, the uplink outage probability, according to formula 8, is:

_outage(R) = PL_ < 10 (R) +PrPr maxmaxmax lglg If soft handovers are involved, an outage would occur only when the path losses of both radio links exceed the maximum path loss allowed. Hence,

PrPr _outage_SHO(R) = PrPr PL_ <maxmaxmax maxmaxmax 10 (R) +lglg primary, 10 (R) +lglg soft Formula 14

wherein,

primary = a + b 1

soft = a + b 2

_outage_SHO(R) = 12

From [A. J. Viterbi 1998] 6.5.2, we can derive:

PrPr−e− 2/2 Q

− ab

2

d

Formula 15

Because the above formula involves integral calculation, we cannot directly use the Excel for calculation but only by querying the table below:

table 8 Relationship between SHO MultiCell gain, edge coverage probability and standard deviation of slow fading

In this version of link budget tool, we can query the above table for the MultiCell gain with ROUND (std. dev. of slow fading) and edge coverage probability.

3.17.1.2 Calculation of the uplink SHO MultiCell gain with the specified area coverage

probability


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If the vendor specifies an area coverage probability, we must, like in formula 5, integrate the coverage probabilities at each point in the cell with a specified slow fading margin. However, because the soft handover area is limited, we must divide the cell coverage area into two parts, i.e. SHO area and non-SHO area, calculate the area coverage probabilities of them respectively, then average the results with area-weighted .

1. SHO area

Suppose the threshold of SHO is Th_SHO dB. All the cells whose path loss discrepancy with the Best Server cell is less than Th_SHO dB will be added to the active set. Based on the round cell Suppossition . The SHO area would be a circle one with its outer radius being R and inner radius being

−Th_SHO10R_SHO = R 10^

At any point in this area, (r, ), there are two links to two BSs, i.e. L_Primary and L_SHO, the path losses of which are respectively:

PL_primary(r, ) = 10 (r) + a + b 1lglg PL_SHO(r, ) = 10 (2R− r) + a + b 2

10 (R) +

lglg Formula 16

An outage will occur only when the path losses of both links exceed the maximum path loss allowed, i.e. lglg . Hence, the outage probability at this point is:

PrPr _outage_SHO(r, , , )

= PrPr minminmin lglg lglg lglg[10 (r) + b 1 , 10 (2R− r) + b 2 ] > 10 (R) + − a dA

= PrPr minminmin 10 ( rRlglg ) + b 1 , 10 ( 2R− rRlglg ) + b 2 > − a dA

= 12 −

e− 2/2Q− 10 (r) − a

blglg

Q− 10 (2 − r) − a

blglg

d

Formula 17

The outage probability curve in terms of distance of points in the SHO area is illustrated in figure below.

0.86 0.88 0.9 0.92 0.94 0.96 0.98

0.235

0.24

0.245

0.25


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Figure 2 Outage probability curve in terms of distance of points in the SHO area

The area coverage probability of the SHO area is equal to the average of coverage probabilities at each point in the area:

PrPr_coverage_SHO_area

= 1(R− R_SHO)2

R_SHO

R

0

2[1 − _outage(r, , , )] r d dr

_coverage_nonSHO_area = 1R_SHO2

PrPr

Formula 18

2. Non-SHO area

Formula 5 is used to calculate the area coverage probability of the non-SHO area, except that the distance integral field changes from (0, R) to (0 , R_SHO).

PrPr0

R_SHO

0

2

Q+ 10 ( 1

rlglg )r drd

Formula 19

3. Area coverage probability of the cell

The area coverage probability of the entire cell is equal to the area-weighted average of the area coverage probability of the SHO area and that of the non-SHO area in terms.

PrPr _coverage_area

= PrPrPrPr_coverage_SHO_area (R − R_SHO)2

+ _coverage_nonSHO_area R_SHO2 /( R2 )

Formula 20

4. Implementation method

Although we can calculate the area coverage probability in the above described method, the calculations are very complex and cannot produce quick result even if they are numerical calculations. In this version of link budget tool, we can use "Tools - Area Coverage Probability" to estimate the edge coverage probability required corresponding to the area coverage probability without soft handover, then calculate the SHO gain in the same method as described in section 3.171.1. Because in the SHO area, the SHO gain will decrease as the discrepancy in strength between the two SHO branches increases, the SHO gain obtained in this method will be overestimated. The same method is used in [NOKIA 2002] 3.1.3, but the possible error that may be caused is not described therein.

3.17.2 Uplink MDC Gain When multiple links involved in a soft handover are combined at RNC on the basis of frames, the process can resist the fast fading to a certain extent when the UE moves at a slow speed, and therefore serves as the link MDC gain where the links are concerned. The value of the uplink MDC gain can be determined through link emulations. [NOKIA 2002] 4.6.1.2 provides some emulation results of the uplink MDC gain.


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Note: [NOKIA 2002] Table 4.7 provides SHO gains at input Eb/Io, and Table 4.8

provides SHO gains at output Eb/Io, which are different from each other. The

difference between them is the fast power control headroom required by the

transmitter. Because the calculation in the link budget is between the transmitter and

receiver, this gain should also be included.

According to the results, the MDC gain will reach its maximum value when the strengths of the two SHO branches are equal to each other, and decrease near to 0 as the discrepancy in strength between them increases. Because what the link budget is concerned about is the cell edge where the path loss between the UE and Best Server cell is the same as the path loss between the UE and the adjacent cell, we will consider the strengths of the two SHO branches equal to each other in the calculation of the SHO MDC gain. The MDC gain varies with different multipath channels. Its value should be determined through link simulations, during which we can assume that the fast fadings over different SHO branches are independent from each other. According to emulation results provided by [NOKIA 2002], this version of link budget tool approximately sets the SHO MDC gain (SHO Gain over Fast Fading) to 1.5dB.

3.17.3 Downlink MultiCell Gain Its calculation is similar to that of the downlink slow fading margin required. Because such parameters as lsc, loc and orthogonality factor in the calculation of the downlink outage probability are closely related to the UE location, cell layout, etc., it is very difficult to calculate the downlink SHO MultiCell gain.

3.17.3.1 Calculation of the downlink SHO MultiCell gain with the specified edge coverage

probability

We can assume that the slow fadings over the uplink and downlink are completely dependent upon each other. Hence, with the edge coverage probability being specified, the calculation of the downlink SHO MultiCell gain is the same as that of the uplink one.

3.17.3.2 Calculation of the downlink SHO MultiCell gain with the area coverage probability


As described above in section 3.14.2.2, because such parameters as lsc, loc and orthogonality factor are closely related to the UE location in the cell, layout, etc., it is very difficult to calculate the downlink SHO MultiCell gain with the area coverage probability required being specified. For the purpose of simplification, we can estimate the edge coverage probability corresponding to the specified area coverage probability without soft handovers being involved, and then calculate the slow fading margin required to ensure this edge coverage probability required with soft handovers being involved in the same method as described in section 3.15.3.1.

3.17.4 Downlink MDC Gain The RAKE combination is used for downlinks. The value of the downlink MDC gain depends upon the multipath channel attribute and should be determined through link emulations in the same method described in section 3.17.2. This version of link budget tool approximately sets the downlink MDC gain to 1.5dB.

3.18 Path Loss


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The path loss on cell edge is equal to the maximum path loss allowed plus the slow fading margin, SHO gain and penetration loss for indoor coverage required to ensure a specified edge/area coverage probability required: Path Loss (dB) = [ EiRP (dBm) - Minimum Signal Strength Required (dBm) ]- Penetration Loss (dB) - Slow Fading Margin (dB) + SHO Gain over Slow Fading (dB)

3.19 Propagation Model Having estimated the mean path loss on cell edge, we can use a mean path loss distribution model to estimate the cell radius. At the network estimation phase when detailed propagation properties of the target area are not available, we can use model COST231-HATA [GSM 03.30]. Frequency f: 1500 - 2000 MHz Base station height Hb: 30 - 200 m Mobile height Hm: 1 - 10 m Distance d: 1 - 20 km Large and small cells (i.e. base station antenna heights above roof-top levels of buildings adjacent to the base station). Urban areas (for rural areas the correction factors given in subparagraph 1.3 and 1.4 can be used up to 2000 MHz). Lu (dB) = 46.3 + 33.9*log(f) - 13.82*log(Hb) - a(Hm) +[44.9 - 6.55*log(Hb)]*log(d) + Cm with : a(Hm) =[1.1*log(f) - 0.7]*Hm -[1.56*log(f) - 0.8] Cm = 0 dB for medium sized city and suburban centres with moderate tree density Cm = 3 dB for metropolitan centres As stated above, this model is applicable to a propagation distance range of 1-20km. In practice, an error may occur if the cell radius is less than 1km. Compared with model Walfish-Ikagami, model COST231-HATA may greatly underestimate the number of base stations required. Hence, whenever possible, we should use the model that has being corrected based on CW test data to estimate the cell radius .

4 Definitions of Functions

4.1 Calculation of the Area Coverage Probability

4.1.1 Function Name area_coverage

4.1.2 Purpose To calculate the area coverage probability with the slow fading margin being specified. According to [Rappaport 1996] 3.9.3:

0

1

0

2

Pedge + 10 ( 1rParea( , , ) = 1 lglg ), r dr d

= 12 1 − (a) + ( 1 − 2ab

b2 erferferf 1 − abberferferf expexpexp ) 1 −


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Formula 21

wherein,

a =2

b =102

(e)lglg

4.1.3 Input Parameters 1. Slow fading margin

fading_margin (dB)

2. Standard deviation of slow fading

stddev_of_slow_fading (dB)

3. Path loss factor

Pathloss_factor

At present, the path loss factor is calculated also based on the propagation model selected. The formulas are: 1. If model COST231-HATA is selected, Pathloss_factor=(44.9-6.55log10(Hb))/10, wherein “Hb” is the base station height; 2, If model Asset is selected, Pathloss_factor=(k2 + k6*log10(Hb))/10.

4.1.4 Returned Value Area coverage probability, range (0, 1).

4.1.5 Implementation Function area_coverage(fading_margin, stddev_of_slow_fading, pathloss_factor)

Dim a As Double

Dim b As Double

Dim c As Double

Dim d As Double

Dim e As Double

e = 2.71828

a = -fading_margin / stddev_of_slow_fading / Sqr(2)

b = 10 * pathloss_factor * Log10(e) / stddev_of_slow_fading / Sqr(2)

c = Exp((1 - 2 * a * b) / (b * b))

d = 1 - MY_Erf((1 - a * b) / b, stddev_of_slow_fading)

area_coverage = 0.5 * (1 - MY_Erf(a, stddev_of_slow_fading) + c * d)

End Function

4.1.6 Functions Called

4.1.6.1 LOG10


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Static Function Log10(X)

Log10 = Log(X) / Log(10#)

End Function

4.1.6.2 MY_Erf

Static Function MY_Erf(X, sigma)

Dim M As Double

Dim e As Double

e = 2.71828

M = -Sqr(2) * X * sigma

MY_Erf = 1 - 2 * Application.WorksheetFunction.LogNormDist(10 ^ M, 0, sigma /

Log10(e))

End Function

4.2 Calculation of the Slow Fading Margin

4.2.1 Function Name "Link Budget".Worksheet_SelectionChange

4.2.2 Purpose This function is an event-trigged callback function which is automatically called once a selection field in sheet “Tools” changes.

4.2.3 Input Parameters Target, Excel.Range type, inputted by Excel upon callback , not used by this

function.

4.2.4 Returned Value None. Directly Change the value of the corresponding cell in sheet "Link Budget".

4.2.5 Implementation Private Sub Worksheet_SelectionChange(ByVal Target As Excel.Range)

Worksheets("Tools").Range("D9").GoalSeek _

Goal:=Worksheets("Tools").Range("C9"), _

ChangingCell:=Worksheets("Tools").Range("C13")

End Sub

4.2.6 Functions Called GoalSeek, an Excel embedded Visual Basic function. For details, please refer to Help in Excel.

4.3 Model COST231_HATA


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4.3.1 Function Name COST231_HATA

4.3.2 Purpose To use model COST231_HATA to calculate the propagation distance with the specified path loss

4.3.3 Input Parameters 1. Path loss

PL, Double type (dB)

2. Frequency

f, Double type (MHz)

3. Base station height

Hb, Double type (m)

4. Mobile height

Hm, Double type (m)

5. Morphology

E, Integer type:

E = 1: Dense urban

E = 2: Urban

E = 3; Sub urban

E = 4: Rural area

E = 5: Highway

4.3.4 Returned Value Distance, Double type(km).

4.3.5 Implementation Function COST231_HATA(PL As Double, f As Double, Hb As Double, _

Hm As Double, e As Integer) As Double

Dim a As Double

Dim k As Double

Dim E_factor As Double

Dim gamma As Double

a = 46.3 + 33.9 * Log10(f)

k = 3.2 * (Log10(11.75 * Hm)) ^ 2 - 4.97

If e = 1 Then

E_factor = 3


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ElseIf e = 2 Then

E_factor = 0

ElseIf e = 3 Then

E_factor = -2 * (Log10(f / 28)) ^ 2 - 5.4

ElseIf e = 4 Then

E_factor = -4.78 * (Log10(f)) ^ 2 + 18.33 * Log10(f) - 40.94

ElseIf e = 5 Then

E_factor = -4.78 * (Log10(f)) ^ 2 + 18.33 * Log10(f) - 35.94

End If

gamma = 44.9 - 6.55 * Log10(Hb)

COST231_HATA = 10 ^ ((PL - a + 13.82 * Log10(Hb) + k - E_factor) / gamma)

End Function


4.3.6.1 LOG10

4.4 ASSET Standard MacroCell Model

4.4.1 Function Name COST231_HATA

4.4.2 Purpose To use model COST231_HATA to calculate the propagation distance with the path loss being specified.

4.4.3 Input Parameters 1. Path loss

PL, Double type (dB)

2. Frequency

f, Double type (MHz)

3. base station height

Hb, Double type (m)

4. Mobile height

Hm, Double type (m)

5. Propagation model parameters

k1 ~ k7 & Clutter Loss: Corrected propagation model parameters

4.4.4 Returned Value Distance, Double type (km).


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4.4.5 Implementation Function ASSET_StdMacro(PL As Double, f As Double, Hb As Double, Hm As

Double, _

k1 As Double, k2 As Double, k3 As Double, k4 As Double, k5 As

Double, _

k6 As Double, k7 As Double, ClutterLoss As Double) As Double

Dim Loss As Double

Dim gamma As Double

Dim Heff As Double

Heff = Hb - Hm

Loss = PL - (k1 + k3 * Hm + k4 * Log10(Hm) + k5 * Log10(Heff) + k7 +

ClutterLoss)

gamma = k2 + k6 * Log10(Heff)

ASSET_StdMacro = 10 ^ (Loss / gamma)

End Function


4.4.6.1 LOG10

5 Instructions for Use

5.1 Launch the Link Budget Tool This version of link budget tool is implemented by Excel. Before launching it, make sure Excel97 or higher version has been installed on the computer. Because macros will be used, Excel Viewer cannot work normally. If the macro virus protection feature is enabled, Excel will prompt you to enable or disable macro. Please select “Enable macro” when prompted. A change protective password (wlgh) has been set to avoid accidental changes to the design. It is recommended to open the worksheets in “read only” mode that allows you to make changes but not save them. To save changes, please use “Save as” to acquire your own version. The link budget sheet is the sheet named “Link Budget”. Sheet "Tools" contains the following two tools: 1. Cable Loss Estimation 2. Area Coverage Probability All other sheets are auxiliary sheets which should not be changed unless absolutely necessary.


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5.2 Set the Scenario Scenarios used in the link budget are in the sheet "Scenarios". The user should elect an appropriate scenario to obtain a correct cell radius.

5.3 Set-by-User Parameters Except “Scenarios”, all the set-by-user cells in Sheet "Link Budget" are displayed in light blue. Meanings of background colors of cells in the sheet are as follows:

Figure 3 Meanings of cell background colors

In this version of link budget tools, parameters to be set by user include: 1. Maximum downlink Traffic Channel output power 2. Cable loss 3. Uplink/downlink cell loading 4. Edge coverage probability required 5. Base station height 6. Downlink frequency 7. Parameters of ASSET Std MacroCell model. Recommended settings for these parameters are as follows:

5.3.1 Maximum Output Power of Downlink TCH If the maximum TCH output powers in the system have been already set, directly use the setting values. At the estimation phase, there are two cases, coverage limited and capacity limited. In the case of coverage limited, the objective of the planning is to expand the cell coverage area as large as possible, and the maximum downlink TCH output power should be set to balance the uplink and downlink coverage within an appropriate range. In the case of capacity limited, we may need to limit the maximum downlink output power and as a result, the downlink coverage area will be less than the uplink one. Please note that because in the calculation process of the downlink interference margin we have assumed that the downlink and uplink are balanced, if it is not the truth, there will be an error in the calculated downlink interference margin. To avoid this, we can adjust the maximum uplink TCH output power of to balance the uplink and downlink coverage. Because of the automatic calculation units, we may need to go through several iterations to achieve this result.

5.3.2 Cable Loss The current version of link budget tool sets the cable loss to 3.0dB by default. In practice, we should set it to the actual value. At the estimation phase when the feeder cable length is still unknown, we should set this parameter according to the installation mode (mounted in building or on tower).


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Please note that in this version of link budget tool, the uplink cable loss parameter set by user is located at C19 , while the downlink cable loss is calculated based on the uplink one. Without TMA being used, the cable loss is defined as the total loss of all the parts along the signal path from the cabinet-top connector to antenna connector. With TMA being used, the cable loss is defined as the total loss of all the parts along the signal path from the cabinet-top connector to TMA connector. Please refer to section 3.3 for the reason why it should be so defined.

5.3.3 Uplink/Downlink Cell Loading The uplink and downlink cell loadings are associated with each other, and should be calculated based on the user density, service model and service ratio. Please note that the downlink cell loading is defined as the average output power of BS/maximum output power of BS ([Dodoo Margin 20020702]).

5.3.4 Edge Coverage Probability Required If the vendor has specified the required edge coverage probability, set this parameter to it. Sometimes, the vendor will specify an area coverage probability rather than an edge coverage probability, say, “Available in over 95% part of the area and 99% of time”. In this case, we can use tool Area Coverage Probability in sheet "Tools" to estimate the area coverage probability. To use this tool, we must set the standard deviation of slow fading and path loss factor. The standard deviation of slow fading can be set refer to the value in sheet “Link Budget”, while the typical values of the path loss factor in various morphologies are listed below:

table 9 Typical values of the path loss factor in various morphologies Morphology Path loss factor

Dense urban 4.5

Urban 4.2

Sub urban 3.8

Rural area 3.3

Highway 3.3

Note: If the penetration loss is included in the link budget to ensure indoor coverage, the coverage probability for outdoor subscribers is higher than that for indoor subscribers for lack of this penetration loss, thus lowering the slow fading margin required to ensure a specified edge coverage probability. We should take this factor into consideration while setting the edge coverage probability, and calculate the indoor edge coverage probability based on the known ratio between indoor and outdoor subscribers. Below is a simplified calculation method. Suppose there are X% users which are outdoor subscribers whose coverage probability is nearly 100%. Then, the indoor edge coverage probability required=(general edge coverage probability required-X)/(1-X). In the commercial network bidding process, we should negotiate with the vendor on this setting method to reach a common understanding. To ensure the coverage


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quality, we recommend that the setting of the edge coverage probability required should not be less than 75%.

5.3.5 Base Station Height It should be set according to the actual situation. The typical value is 30m.

5.3.6 Downlink Frequency It should be set on a case-to-case basis. The typical value is the central frequency of the core band, i.e. 2140MHz. There is no need to change this value for it does not have a great impact on the path loss. The downlink frequency is associated with the uplink frequency. Uplink frequency =downlink frequency-190MHz.

5.3.7 Parameters of ASSET Std. MacroCell Model If the model has been corrected for the target area, we can use ASSET Std. MacroCell model to estimate the cell radius. In this case, we should set the parameters k1~k7 and Clutter Loss based on the model correction results. Please note that “Clutter” type should be the major “clutter type” in the target area. The current version of link budget tool provides the default values of k1~k7. Please note that these default values are derived from the COST231-HATA model, with the frequency set to 2130MHz because this frequency is often used for model correction. When Asset model is used, the impact of the difference between uplink and downlink frequencies has already been taken into consideration. Because we cannot import the terrain map into the link budget, we will not consider the diffraction loss. However, because parameter k7 of ASSET Std. MacroCell model is mainly used to reflect the diffraction loss, we should set k7 to zero in the link budget tool when using this model.

5.4 Export Link Budget Results The “exporting the link budget results” function is added to the link budget tool V3.30, which makes it easy to refer to link budget results in the planning documents. Click the “Export” button on the right of “Scenario” setting term in sheet “Link Budget” the link budget results will be exported to the sheet “Results”. Check “Export UL only” to export uplink budget results only. Click the “Clear” button in sheet “Results” to clear exported results. The link budget tool V3.40 has removed the bug that causes an exporting error in the antenna diversity mode.

5.5 Other Issues

5.5.1 Existing Link Performance Data Sheets “NodeB_Perf” and “UE_Perf” contain some parameters related to the link performance . These parameters are set based on the WCDMA RNP Link Performance Data Version 2.10 provided by Link simulation Team. Parameters that have not available simulation results are marked as "N/A". An error may occur due to the unavailability of some parameters when the scenario setting is changed. This issue will be addressed through the link emulation works.


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Because our link performance is confidential information, in link budget tool V3.40, sheets containing these data are hidden.

5.5.2 OTSR Configuration Though Huawei NodeB V100R003 supports OTSR configuration, the current version of link budget tool does not provide the corresponding scenario. Because only uplink/downlink RF channel specifications will change as a result of the OTSR configuration ,and the others almost remain the same as in the 3-sector directional configuration, we can change the default value in the link budget tool to get the cell coverage result in this configuration.

5.5.3 Product & Auxiliary Equipment Performance and Version All the equipment parameters used in the Link Budget tool (link performance and RF channel performance) are based on NodeBV100R003. An update of the product version and auxiliary equipment may result in changes in the settings of these parameters,This can be realized by changing their default values. Later versions of link budget tools will be developed for each product version and auxiliary equipment.


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List of References:

[1] [A. J. Viterbi 1998] Andrew J. Viterbi, Principles of Spread Spectrum Communication,

ADDISON-WESLEY,1998

[2] [NOKIA 2002] Janna Laiho, Achim Wacker,etc., Radio Network Planning and Optimisation

for UMTS, John Wiley & Sons LTD., 2002

[3] [GSM 03.30] Digital Cellular Telecommunication Systems: Radio Network Planning Aspects,

GSM 03.30 Ver 7.0.0 Release 1998, ETSI

[4] [Mehta&Greenstein VTC'02] N. B. Mehta, L. Greenstein, T. Willis, Z. Kostic.“Analysis and

Results for the Orthogonality Factor in WCDMA Downlinks,” Submitted to IEEE Trans.

Wireless Commun., VTC’02 (spring)

WCDMA RNP Design Specifications for the Link Budget Tool-20050526-A-3.5

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