TRX Cooperation(GBSS13.0 02)

TRX Cooperation GBSS13.0

Feature Parameter Description

Issue

02

Date

2012-06-30

HUAWEI TECHNOLOGIES CO., LTD.

Copyright © Huawei Technologies Co., Ltd. 2012. All rights reserved. No part of this document may be reproduced or transmitted in any form or by any means without prior written consent of Huawei Technologies Co., Ltd.

Trademarks and Permissions and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd. All other trademarks and trade names mentioned in this document are the property of their respective holders.

Notice The purchased products, services and features are stipulated by the contract made between Huawei and the customer. All or part of the products, services and features described in this document may not be within the purchase scope or the usage scope. Unless otherwise specified in the contract, all statements, information, and recommendations in this document are provided "AS IS" without warranties, guarantees or representations of any kind, either express or implied. The information in this document is subject to change without notice. Every effort has been made in the preparation of this document to ensure accuracy of the contents, but all statements, information, and recommendations in this document do not constitute the warranty of any kind, express or implied.

Huawei Technologies Co., Ltd. Address:

Huawei Industrial Base Bantian, Longgang Shenzhen 518129 People's Republic of China

Website:

http://www.huawei.com

Email:

[email protected]

GSM BSS TRX Cooperation

Contents

Contents 1 About This Document ..............................................................................................................1-1 1.1 Scope ............................................................................................................................................ 1-1 1.2 Intended Audience......................................................................................................................... 1-1 1.3 Change History.............................................................................................................................. 1-1

2 Overview......................................................................................................................................2-1 3 Technical Description ..............................................................................................................3-1 3.1 BCCH TRX Cooperation ............................................................................................................... 3-1 3.1.1 BSC-controlled BCCH TRX cooperation .............................................................................. 3-1 3.1.2 BSC-Collaborated BCCH TRX Cooperation ........................................................................ 3-4 3.1.3 BTS-Controlled BCCH TRX Channel Cooperation .............................................................. 3-7 3.2 Baseband FH TRX Cooperation ................................................................................................... 3-8

4 Related Features .......................................................................................................................4-1 5 Impact on the Network.............................................................................................................5-2 5.1 Impact on System Capacity........................................................................................................... 5-2 5.2 Impact on Network Performance................................................................................................... 5-2

6 Engineering Guidelines ...........................................................................................................6-3 6.1 When to UseTRX Cooperation ...................................................................................................... 6-3 6.2 Deploying TRX Cooperation ......................................................................................................... 6-3 6.3 Performance Optimization ............................................................................................................. 6-3 6.4 Troubleshooting ............................................................................................................................. 6-3

7 Parameters..................................................................................................................................7-4 8 Counters ......................................................................................................................................8-1 9 Glossary ......................................................................................................................................9-1 10 Reference Documents .........................................................................................................10-1

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Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd

i


1 About This Document

1 About This Document 1.1 Scope This document describes the GBFD-113801 TRX Cooperation feature, including BCCH TRX cooperation and baseband FH TRX cooperation.

1.2 Intended Audience This document is intended for: 

Personnel who need to understand the TRX Cooperation feature



Personnel who work with Huawei GSM products

1.3 Change History The section provides information about the changes in different document versions. There are two types of changes, which are defined as follows: 

Feature change: refers to a change in the TRX Cooperation feature of a specific product version.



Editorial change: refers to a change in wording or the addition of the information that was not described in the earlier version.

Document Issues The document issues are as follows: 

02(2012-06-30)



01 (2011-03-31)



Draft A (2011-01-15)

02 (2012-06-30) This is the first release of GBSS13.0. Compared with issue 01 (2011-03-31)) of GBSS13.0, this issue incorporates the changes described in the following table. Change Type

Change Description

Parameter Change

Feature change

None

None

Editorial change

Added the following chapters:

None



Chapter 4 "Related Features"



Chapter 5 "Impact on the Network"



Chapter 6 "Engineering Guidelines"

01 (2011-03-31) This is the first release of GBSS13.0.

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1 About This Document

Compared with issue draft A (2011-01-15) of GBSS13.0, issue 01 (2011-03-31) of GBSS13.0 has no change.

Draft A (2011-01-15) This is the draft release of GBSS13.0. Compared with issue 01 (2010-06-30) of GBSS12.0, issue Draft A (2011-01-15) of GBSS13.0 has no change.

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2 Overview

2 Overview TRX cooperation is categorized into the following types: 

BCCH TRX cooperation When the BCCH TRX fails, the BSC selects a normal TRX as the new BCCH TRX according to the TRX cooperation algorithm to ensure that the cell is functional. When the fault in the original BCCH TRX is rectified, the BSC can switch the main BCCH back to the original TRX. When the physical TRX board or channel bound to a logical TRX fails, the BTS binds the logical TRX to a normal TRX board or channel, ensuring that the logical TRX works normally.



Baseband FH TRX cooperation Baseband FH TRX cooperation is a function enabled by the BSC when a TRX involved in FH is faulty in a cell whose FHMODE is set to BaseBand_FH(Baseband frequency hopping). In such a case, the BSC removes the faulty TRX from the FH group, whereas other TRXs in the FH group remain BaseBand_FH(Baseband frequency hopping).

TRX cooperation ensures that the cell works normally when faults occur on the TRXs in the cell. From the time of service disruption due to TRX failure to the time of service recovery after TRX cooperation, the system determines whether TRX cooperation is required, hands over the calls in the faulty cell to another cell, and re-initializes the cell.

TRX cooperation is not triggered within a certain period after the cell is initialized. The period is determined by AIDDELAYPROTECTTIME. By default, AIDDELAYPROTECTTIME is set to 15 minutes.

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3 Technical Description

3 Technical Description 3.1 BCCH TRX Cooperation When the BCCH TRX in a cell is unavailable, the BSC designates another available TRX in the cell to replace the original BCCH TRX, ensuring that the cell is functional. When the fault in the original BCCH TRX is rectified, the BSC can switch the main BCCH back to the original TRX. BCCH TRX cooperation involves the following: 

BCCH TRX cooperation



BCCH TRX switchback

BCCH TRX cooperation can be classified into the following types by the initiator: 

BSC-controlled BCCH TRX cooperation



BSC-collaborated BCCH TRX cooperation



BTS-controlled BCCH TRX channel cooperation

3.1.1 BSC-controlled BCCH TRX cooperation BSC-controlled BCCH TRX cooperation means that the BSC controls BCCH TRX cooperation and the BTS implements BCCH TRX cooperation. BSC-controlled BCCH TRX cooperation involves the following: 

BSC-Controlled BCCH TRX Cooperation



BSC-Controlled BCCH TRX Switchback

BSC-Controlled BCCH TRX Cooperation BCCH TRX cooperation is triggered when the BTS reports the status change message regarding the following: 

The operating status of the current main BCCH is DISABLED.



The availability status of the current main BCCH must be one of those listed in Table 3-1.

Table 3-1 Availability status and meaning Availability Status

Description

POWER_OFF

Indicates that the equipment is powered off.

FAILED

Indicates that the equipment fails.

NOT_INSTALLED_REAL

Indicates that the equipment is not installed.

DEPENDENCY

Indicates that the equipment is unavailable because of other faulty equipment.

The cell ID in the BCCH TRX cooperation message is used to identify the cell where BCCH TRX cooperation is performed. BCCH TRX cooperation can be performed concurrently in different cells. The process of BCCH TRX cooperation is as follows:

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1. When a cell satisfies the conditions for BCCH TRX cooperation, the BSC starts a protection timer with the duration as one minute. The 1-minute protection timer can avoid TRX cooperation caused by unstable TRX status.

2. After the protection timer expires, the BSC checks whether the cell satisfies the conditions for TRX cooperation again. − If

the cell satisfies the conditions, the BSC forcibly hands over all the calls in the cell and starts a 10-second timer.

− If

the cell does not satisfy the conditions, the BSC terminates the process of TRX cooperation.

3. After all the calls in the cell are handed over or the 10-second timer expires, the BSC selects an available TRX in the cell to replace the original BCCH TRX. 4. The BSC initializes the cell and sends the new configuration data to the BTS. In addition, the BSC exchanges the configuration data of the original BCCH TRX with the configuration data of the cooperating TRX. Then, BCCH TRX cooperation is complete.

BSC-Controlled BCCH TRX Switchback After the BCCH TRX cooperation, if the fault on the original BCCH TRX in the cell is rectified, BCCH TRX switchback is performed. The configuration data of the two TRXs involved in TRX cooperation is adjusted, and the initial configuration data of the cell is restored. The process of BCCH TRX switchback is reverse to that of BCCH TRX cooperation. The differences between them are the triggering conditions and processing. TRX switchback is controlled by TRXAIDSWITCH. BCCH TRX switchback is triggered when the BTS reports a status change message indicating that the operating status of the original main BCCH is DISABLED. The cell ID in the BCCH TRX switchback message is used to identify the cell where BCCH TRX switchback is performed. BCCH TRX switchback can be performed concurrently in different cells. If the triggering conditions are satisfied, BCCH TRX switchback is performed. Finally, the initial configuration data before TRX cooperation is restored.

Algorithm for Selecting the Cooperating TRX The TRX boards to which each logical TRX belongs differ in the frequency band and POWT; therefore, selection of a cooperating TRX should satisfy certain conditions. 

Mandatory conditions − The

original BCCH TRX and the candidate TRX must be in the same BTS cabinet group.

− The

TRX board bound to the original BCCH TRX can exchange the frequency with the TRX board bound to the candidate TRX. The exchanged frequencies must belong to the frequency band supported by the TRX board.

− If

the original BCCH TRX or the candidate TRX is connected to the Power Boost Unit (PBU), the PBU must support the exchanged frequencies.

− The

antenna feeder boards connected to the original BCCH TRX and candidate TRX must support the exchanged frequencies. The antenna feeder boards include the Combing and Distribution Unit (CDU), Enhanced Duplexer Unit (EDU), Dual-Duplexer Unit for DTRU BTS (DDPU), Filter Combiner Unit for DTRU BTS (DFCU), and Filter Combiner Unit for DTRU BTS (DFCB). Besides the preceding conditions, the DFCU and DFCB must meet the requirements for the Absolute Radio Frequency Channel Number (ARFCN) difference. The requirements are as follows:

− For

the frequencies on the 900/850 MHz band, the ARFCN difference must be at least 3.

− For

the frequencies on the 1800/1900 MHz band, the ARFCN difference must be at least 2.

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− The

QTRU(Quadruple-Transceiver Unit) adopts the power sharing technology; therefore, the maximum power can be set to different values when the numbers of logical TRXs bound to the QTRU are different. If the TRX board of the original BCCH TRX or the candidate TRX is a QTRU, the power of the TRX after BCCH TRX cooperation cannot be greater than the maximum power of the QTRU.



Condition for Selecting Preferable TRXs In a cell, multiple candidate TRXs may satisfy the mandatory conditions. These candidate TRXs are filtered to select an optimum cooperating TRX with the minimum impact on services. Table 3-2 lists the conditions for selecting preferable TRXs. The priorities of the conditions decrease from the top down.

Table 3-2 Conditions for selecting preferable TRXs PRI

Condition for Selecting Preferable TRXs

Description

1

HW_Concentric Attribute

The candidate TRX with the same concentric attribute as that of the original BCCH TRX is preferably selected. That is, they are in an underlaid subcell or an overlaid subcell.

2

QTRU bandwidth

If the original BCCH TRX or the candidate TRX is bound to a QTRU, the candidate TRX that meets the bandwidth requirement of every carrier frequency of the QTRU after frequency exchange is preferably selected. If neither the original BCCH TRX nor the candidate TRX is bound to a QTRU, the condition is considered as satisfied. The candidate TRX that has the same capability in supporting the EDGE as the original BCCH TRX is preferably selected. That is, both of them support the EDGE or neither of them supports the EDGE.

3

Support of EDGE

4

RF send and receive modes of The candidate TRX that is the the TRX same as the original BCCH TRX in the RF RCVMD and SNDMD is preferably selected. If neither of the original BCCH TRX nor the candidate TRX supports the RF RCVMD and SNDMD, this condition is considered as satisfied.

5

CBCH configuration

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The candidate TRX that is not configured with the CBCH is preferably selected.


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PRI


Description

6

PDCH configuration

The candidate TRX that is not configured with the PDCH is preferably selected.

Do as follows to select the cooperating TRX based on the conditions listed in Table 3-2: 1. Apply the condition with the highest priority to filter all the non-BCCH TRXs in the cell. − If

only one logical TRX satisfies the condition after filtering, the logical TRX is selected as the cooperating TRX.

− If

multiple logical TRXs satisfy the condition, these logical TRXs are used in the next round of filtering, as described in step 2.

− If

no logical TRX satisfies the condition, all logical TRXs are used in the next round of filtering, as described in step 2.

2. Apply the condition with the priority one level lower to filter the logical TRXs available for further filtering. − If


− If

multiple logical TRXs or no logical TRX satisfies the condition after filtering, repeat step 2.

− If

multiple logical TRXs or no logical TRXs satisfy the condition of the lowest priority, select any one of these logical TRXs as the cooperating TRX.

3.1.2 BSC-Collaborated BCCH TRX Cooperation BSC-collaborated BCCH TRX cooperation is performed by the BSC and the BTS. The fundamentals are the same as those of BSC-controlled BCCH TRX cooperation. The difference between them is that the BTS initiates BCCH TRX cooperation and selects the cooperating TRX in BSC-collaborated BCCH TRX cooperation. The BSC only exchanges the configuration data of the original BCCH TRX with the configuration data of the cooperating TRX upon the cooperation request of the BTS. BSC-collaborated BCCH TRX cooperation involves the following: 

BSC-collaborated BCCH TRX cooperation



BSC-collaborated BCCH TRX switchback

BSC-Collaborated BCCH TRX Cooperation The triggering conditions of BSC-collaborated BCCH TRX cooperation are the same as those of BSC-controlled BCCH TRX cooperation. When the BTS detects that the main BCCH satisfies the following conditions, BCCH TRX cooperation is triggered: 

The operating status of the current main BCCH is DISABLED.



The availability status of the current main BCCH must be one of those listed in Table 3-3.


Meaning

POWER_OFF


FAILED


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Availability Status

Meaning

NOT_INSTALLED_REAL


DEPENDENCY


The process of BSC-collaborated BCCH TRX cooperation is as follows: 1. When a cell satisfies the conditions for BSC-collaborated BCCH TRX cooperation, the BTS starts a protection timer with the duration as two minutes. The 2-minute protection timer can avoid TRX cooperation caused by unstable TRX status.

2. After the protection timer expires, the BTS sends a request to the BSC for forcibly handing over all the calls in the cell and starts a 10-second timer. 3. After the handovers of all the calls in the cell are complete or the 10-second timer expires, the BTS selects a functional cooperating TRX in the cell and sends a TRX cooperation request to the BSC. 4. The BSC initializes the cell and sends the new configuration data to the BTS. In addition, the BSC exchanges the configuration data of the original BCCH TRX with the configuration data of the cooperating TRX. Then, BCCH TRX cooperation is complete.

BSC-Collaborated BCCH TRX Switchback After BSC-collaborated BCCH TRX cooperation, if the fault on the original BCCH TRX in the cell is rectified, BSC-collaborated BCCH TRX switchback is performed. The configuration data of the two TRXs involved in TRX cooperation is adjusted, and the initial configuration data of the cell is restored. The process of BCCH TRX switchback is reverse to that of BCCH TRX cooperation. The differences between them are the triggering conditions and processing. TRX switchback is controlled by TRXAIDSWITCH. The triggering conditions of BSC-collaborated BCCH TRX switchback are as follows: 

The BTS detects that the operating status of the original main BCCH is ENABLED.



TRXAIDSWITCH is set to TRX Aiding Not Allowed.



The triggering conditions of TRX cooperation are not satisfied after dynamic configuration. If the BCCH TRX is still faulty after BCCH TRX switchback, BCCH TRX cooperation is triggered again.

If the triggering conditions are satisfied, BCCH TRX switchback is performed. The process of BCCH TRX switchback is reverse to that of BCCH TRX cooperation. Finally, the initial configuration data before TRX cooperation is restored.

Algorithm for Selecting the Cooperating TRX The TRX boards to which each logical TRX belongs differ in the frequency band and POWT; therefore, selection of a cooperating TRX should satisfy certain conditions. 


original BCCH TRX and the candidate TRX must have the same power type.

− The

original BCCH TRX and the candidate TRX must be the same in the RF RCVMD and SNDMD.

− After

TRX cooperation, the frequencies of the original BCCH TRX must belong to the frequency band of the board that carries the candidate TRX.

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− After

TRX cooperation, the frequencies of the original BCCH TRX must meet the bandwidth requirements of the board that carries the candidate TRX. The bandwidth consists of the tributary output bandwidth and the board input bandwidth.



Conditions for selecting preferable TRXs In a cell, multiple candidate TRXs may satisfy the mandatory conditions. These candidate TRXs are filtered to select an optimum cooperating TRX with the minimum impact on services. Table 3-4 lists the conditions for selecting preferable TRXs. The priorities of the conditions decrease from the top down.

Table 3-4 Conditions for selecting preferable TRXs Priority

Condition

Meaning

1

Diversity

The candidate TRX that is the same as the original BCCH TRX in the RF RCVMD and SNDMD is preferably selected. If the SNDMD of the RF TRX is set to Diversity Transmitter, the candidate TRX whose diversity can work normally after TRX cooperation is preferably selected.

2

Frequency band

The candidate TRX whose frequencies are on the frequency band of the board that carries the original BCCH TRX is preferably selected.

3

Bandwidth

The candidate TRX whose frequencies meet the bandwidth requirement of the board that carries the original BCCH TRX is preferably selected.

4

CBCH configuration

The candidate TRX that is not configured with the CBCH is preferably selected.

5

PDCH configuration

The candidate TRX that is not configured with the PDCH is preferably selected.

Do as follows to select the cooperating TRX based on the conditions listed in Table 3-4: 1. Apply the condition with the highest priority to filter all the non-BCCH TRXs in the cell. − If


− If

multiple logical TRXs satisfy the condition, these logical TRXs are used in the next round of filtering, as described in step 2.

− If

no logical TRX satisfies the condition, all logical TRXs are used in the next round of filtering, as described in step 2.

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2. Apply the condition with the priority one level lower to filter the logical TRXs available for further filtering. − If


− If

multiple logical TRXs or no logical TRX satisfies the condition after filtering, repeat step 2.

− If

multiple logical TRXs or no logical TRXs satisfy the condition of the lowest priority, select any one of these logical TRXs as the cooperating TRX.

3.1.3 BTS-Controlled BCCH TRX Channel Cooperation When the physical TRX board or channel bound with a logical TRX carrying the BCCH fails, the BTS binds the logical TRX to a functional TRX board or channel, ensuring that the logical TRX works properly. In BTS-controlled BCCH TRX channel cooperation mode, the parameters of the logical TRX are not changed; however, the physical TRX board or channel bound to the logical TRX is changed. BTS-controlled BCCH TRX channel cooperation is performed by the BTS independently without the cooperation of the BSC. BTS-controlled BCCH TRX channel cooperation involves the following: 

BTS-controlled BCCH TRX channel cooperation



BTS-controlled BCCH TRX channel switchback

BTS-Controlled BCCH TRX Channel Cooperation The triggering condition of BTS-controlled BCCH TRX channel cooperation is the same as that of BSC-collaborated BCCH TRX cooperation. If the original BCCH TRX has the LAPD alarm or is manually blocked, BTS-controlled BCCH TRX channel cooperation is not performed.

BTS-Controlled BCCH TRX Channel Switchback The triggering condition of BTS-controlled BCCH TRX channel switchback is the same as that of BSC-collaborated BCCH TRX switchback.

Algorithm for Selecting the Cooperating TRX If no TRXs on the board meet the requirements for BCCH TRX cooperation, a TRX on the antenna tributary is bound to the TRX on the tributary of the BCCH TRX, ensuring that the BCCH TRX can work normally. The algorithm for selecting a TRX on the board is the same as the algorithm for selecting the cooperating TRX in BSC-collaborated BCCH TRX cooperation. The algorithm of the cooperation between the TRX on the antenna tributary and the TRX on the tributary of the BCCH TRX is described as follows: 


3G TRX is not configured on the tributary of the original BCCH TRX and the candidate tributary.

− The

tributary of the original BCCH TRX and the candidate tributary must belong to the same cell.

− The

board of the tributary that carries the original BCCH TRX is the same as the board of the candidate tributary in the frequency band.

− For

M series TRX modules configured with two transmit channels, the number of TRXs configured on the candidate tributary must be the same as the number of TRXs configured on the tributary of the BCCH TRX.

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− The

cooperating TRX must meet the requirement of the candidate tributary for the maximum output power.

− The 

cell where the original BCCH TRX is located is not configured with the multi-site cell function.

Conditions for selecting preferable TRXs Multiple channels or boards may satisfy the mandatory conditions. These channels or boards are filtered to select an optimum channel or board as the cooperating channel or board based on the conditions listed in Table 3-5. The priorities of the conditions decrease from the top down.

Table 3-5 Conditions for selecting preferable channels or boards Priority


1

Bandwidth of the original BCCH The original BCCH TRX should TRX meet the bandwidth requirement of the board after TRX channel cooperation.

2

Bandwidth of the cooperating channel

3

Diversity bandwidth when the If the RF SNDMD of the logical RF SNDMD of the logical TRX TRX bound to the original main bound to the original main BCCH is Diversity BCCH is Diversity Transmitter Transmitter, the diversity should meet the bandwidth requirement of the cooperating channel after TRX channel cooperation.

4

Diversity bandwidth when the RF SNDMD of the cooperating channel is Diversity Transmitter

Meaning

The cooperating channel should meet the bandwidth requirement of the board that carries the original BCCH TRX after TRX channel cooperation.

If the RF SNDMD of the cooperating channel is Diversity Transmitter, the diversity should meet the bandwidth requirement of the cooperating channel after TRX channel cooperation.

3.2 Baseband FH TRX Cooperation Baseband FH TRX cooperation is a function enabled by the BSC when a TRX involved in FH is faulty in a cell whose FHMODE is set to BaseBand_FH(Baseband frequency hopping) or RF_FH(RF frequency hopping). In such a case, the BSC removes the faulty TRX from the FH group, whereas other TRXs in the FH group remain BaseBand_FH(Baseband frequency hopping). After the fault is rectified, the BSC enables the TRX to join the FH group and involve in baseband FH again. Baseband FH TRX cooperation involves the following: 

Baseband FH TRX Cooperation



Baseband FH TRX Switchback

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Baseband FH TRX Cooperation Baseband FH TRX cooperation can be performed only in baseband FH cell when any of the following conditions is satisfied: 

BCCH TRX cooperation is performed in the cell.



The BTS reports the status change message indicating that the operating status of the TRX involved in baseband FH is DISABLED and the availability status of the TRX involved in baseband FH is one of those listed in Table 3-6.


Description

POWER_OFF


FAILED


NOT_INSTALLED_REAL


DEPENDENCY


The cell ID in the baseband FH TRX cooperation message is used to identify the cell where baseband FH TRX cooperation is performed. Baseband FH TRX cooperation can be performed concurrently in different cells. The process of baseband FH TRX cooperation is as follows: 1. When a cell satisfies the conditions for baseband FH TRX cooperation, the BSC starts a protection timer with the duration as one minute. The 1-minute protection timer can avoid TRX cooperation caused by unstable TRX status.

2. After the protection timer expires, the BSC checks whether the cell satisfies the conditions for TRX cooperation again. − If

the cell satisfies the conditions, the BSC forcibly hands over all the calls in the cell and starts a 10-second timer.

− If

the cell does not satisfy the conditions, the BSC terminates the process of TRX cooperation.

3. After all the calls in the cell are handed over or the 10-second timer expires, the BSC removes the frequency of the faulty TRX from the MA list and adjusts the MAIO of other TRXs in the FH group. Meanwhile, other TRXs in the FH group remain BaseBand_FH(Baseband frequency hopping). 4. The BSC initializes the cell and sends the new configuration data to the BTS.

Baseband FH TRX Switchback When the faults in the baseband FH TRX in the cell are rectified, the BSC reverts the FH mode of the cell to Baseband FH. TRX switchback is controlled by TRXAIDSWITCH. If some faulty TRXs in a baseband FH group are restored, the system takes actions according to the setting of the parameter BHPREPOLICY. If the parameter is set to ALL(All), the system performs baseband FH TRX switchback after all the faulty TRXs in the FH group are restored. If the parameter is set to PART(Part), the system performs baseband FH TRX switchback after any of the faulty TRXs in the FH group is restored. After the switchback, the FH group remains in the state of baseband FH TRX cooperation. In such a case, the FH group contains only the TRXs in the normal state. The faulty TRXs remain NO_FH(No frequency hopping). After all the faulty TRXs are restored, the fault is rectified. Issue 02 (2012-06-30)


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The process of baseband FH TRX switchback is reverse to that of baseband FH TRX cooperation. The differences between them are the triggering conditions and processing. Baseband FH TRX switchback can be performed only in the baseband FH cell and is triggered by the required status change message reported from the BTS. The object in the baseband FH TRX switchback message must be of the BT level and must be the TRX involved in the baseband FH. The operating status of the original baseband FH TRX must be ENABLED. The cell ID in the baseband FH TRX switchback message is used to identify the cell where baseband FH TRX switchback is performed. Baseband FH TRX switchback can be performed concurrently in different cells.

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4 Related Features

4 Related Features Feature

Baseband FH TRX cooperation

Prerequisite Feature 

Frequency Hopping (RF hopping, baseband hopping) 

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GBFD-113701

Mutually Exclusive Feature 

GBFD-510104

Affected Feature

None

Multi-site Cell 

GBFD-118701 RAN Sharing

GBFD-113702

Note:

BCCH Carrier Frequency Hopping

If the channel carrying the BCCH TRX is faulty after the preceding features are enabled, TRX Cooperation for the BCCH TRX does not take effects.


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5 Impact on the Network

5 Impact on the Network 5.1 Impact on System Capacity After BCCH TRX cooperation and baseband FH TRX cooperation are enabled, the number of available TRXs in a cell decreases, decreasing cell capacity. When the traffic volume in a cell exceeds the cell capacity, traffic congestion may occur. When certain TRXs enter the intelligent shutdown state to decrease power consumption during off-peak hours, congestion does not occur after baseband FH TRX cooperation is enabled. When BCCH TRX cooperation and baseband FH TRX cooperation are disabled, or the requirements for enabling BCCH TRX cooperation and baseband FH TRX cooperation are not met, a cell is out of service when its BCCH TRX or the TRX participating in FH is faulty. Services in the cell are recovered after TRX faults are rectified.

5.2 Impact on Network Performance When the traffic volume in a cell exceeds the cell capacity, traffic congestion may occur.

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6 Engineering Guidelines

6 Engineering Guidelines 6.1 When to UseTRX Cooperation You are advised to enable TRX Cooperation in all scenarios to reduce the GSM cell out-of-service duration.

6.2 Deploying TRX Cooperation For details about how to activate, verify, and deactivate this feature, see Configuring TRX Cooperation.

6.3 Performance Optimization Monitoring N/A

Parameter Optimization N/A

6.4 Troubleshooting N/A

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7 Parameters

7 Parameters Table 7-1 Parameter description Parameter ID NE

MML Command Feature ID Feature Name Description

AIDDELAYPR BSC6900 SET GBFD-113 TRX OTECTTIME GCELLSOFT(Opt 801 Cooperation ional)

Meaning: Delay time for mutual-aid detection on a cell after the cell is initialized. When the cell initialization has just finished, the cell is in an unstable state. Mutual-aid detection at this time may cause a wrong decision. Therefore, this parameter is used for specifying proper delay. GUI Value Range: 1~60 Actual Value Range: 1~60 Default Value: 15 Unit: min

BHPREPOLIC BSC6900 SET GBFD-113 TRX Y GCELLCCACCE 801 Cooperation SS(Optional)

Meaning: Mutual-aid switchback policy of baseband frequency hopping (FH). If multiple TRXs in a baseband FH group are faulty and switchback is needed after mutual aid of the baseband FH TRXs occurs: If you choose ALL, mutual-aid switchback is implemented after all the TRXs in the FH group recover; if you choose PART, as long as any of the faulty TRXs recovers, it is changed back at once and added to the FH group. GUI Value Range: ALL(All), PART(Part) Actual Value Range: ALL, PART Default Value: ALL Unit: None

FHMODE

GBFD-113 Frequency BSC6900 SET GCELLHOPTP(O 701 Hopping (RF ptional) hopping, baseband hopping)

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Meaning: This parameter specifies the frequency hopping mode of a cell. When this parameter is set to "NO_FH", all the TRXs of the cell do not join in frequency hopping. When this parameter is set to "BaseBand_FH", the cell is in baseband frequency hopping


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Parameter ID NE

7 Parameters

MML Command Feature ID Feature Name Description mode. In this case, there can be TRXs that do not join in frequency hopping on the cell. When this parameter is set to "RF_FH", the cell is in RF frequency hopping mode. In this case, there can be TRXs that do not join in frequency hopping on the cell. When this parameter is set to "Hybrid_FH", the cell is in hybrid frequency hopping. In this case, some TRXs on the cell must join in baseband frequency hopping, some cells on the cell must join in RF frequency hopping, and some cells on the cell must not join in frequency hopping. GUI Value Range: NO_FH(No frequency hopping), BaseBand_FH(Baseband frequency hopping), RF_FH(RF frequency hopping), Hybrid_FH(Hybrid frequency hopping) Actual Value Range: NO_FH, BaseBand_FH, RF_FH, Hybrid_FH Default Value: NO_FH Unit: None

POWT

MRFD-210 Configuration Meaning: This parameter BSC6900 SET GTRXDEV(Optio 301 Management specifies the maximum transmit nal) power supported by the power amplifier of the TRX. The macro BTS and the mini BTS support different power levels. GUI Value Range: 80W(80W), 63W(63W), 60W(60W), 55W(55W), 50W(50W), 45W(45W), 40W(40W), 31W(31W), 30W(30W), 27W(27W), 26W(26W), 25W(25W), 24W(24W), 21W(21W), 20W(20W), 19W(19W), 18W(18W), 17W(17W), 16W(16W), 15W(15W), 14W(14W), 13_3W(13.3W), 13W(13W), 12_5W(12.5W), 12W(12W), 11_5W(11.5W), 11W(11W),

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Parameter ID NE

7 Parameters

MML Command Feature ID Feature Name Description 10W(10W), 9_5W(9.5W), 9W(9W), 8_5W(8.5W), 8W(8W), 7_5W(7.5W), 7W(7W), 6_5W(6.5W), 6W(6W), 5_5W(5.5W), 5W(5W), 4_5W(4.5W), 4W(4W), 3_7W(3.7W), 3_1W(3.1W), 3W(3W), 2_5W(2.5W), 2W(2W), 1_5W(1.5W), 1W(1W), 200mW(200mW), DEFAULT(Default) Actual Value Range: 80W, 63W, 60W, 55W, 50W, 45W, 40W, 31W, 30W, 27W, 26W, 25W, 24W, 21W, 20W, 19W, 18W, 17W, 16W, 15W, 14W, 13_3W, 13W, 12_5W, 12W, 11_5W, 11W, 10W, 9_5W, 9W, 8_5W, 8W, 7_5W, 7W, 6_5W, 6W, 5_5W, 5W, 4_5W, 4W, 3_7W, 3_1W, 3W, 2_5W, 2W, 1_5W, 1W, 200mW, DEFAULT Default Value: DEFAULT Unit: None

RCVMD

MRFD-210 Configuration Meaning: RF receive mode of BSC6900 SET GTRXDEV(Optio 301 Management the TRX. nal) The BTS3012, BTS3012AE, BTS3012II, BTS3006C, and BTS3002E do not support Main Diversity. The DBS3900 GSM and BTS3900 GSM support Four Diversity Receiver and Main Diversity. GUI Value Range: INDEPENDENT(Independent Receiver), DIVIDING(Dividing Receiver), FOURDIVERSITY(Four Diversity Receiver), MAINDIVERSITY(Main Diversity), NONE(None) Actual Value Range: INDEPENDENT, DIVIDING, FOURDIVERSITY, MAINDIVERSITY, NONE Default Value: INDEPENDENT Unit: None

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Parameter ID NE SNDMD

7 Parameters

MML Command Feature ID Feature Name Description

MRFD-210 Configuration Meaning: RF send mode of the BSC6900 SET GTRXDEV(Optio 301 Management TRX. nal) The BTS3006C and BTS3002E do not support Wide Band Combining, Power Booster Technology, DPBT, or Transmitter Independent or Combining. The DBS3900 GSM GRRU does not support Wide Band Combining, Transmitter Independent or Combining, Power Booster Technology, or DPBT. The BTS3900 GSM and BTS3900A GSM do not support Transmitter Independent or Wide Band Combining. GUI Value Range: NOCOMB(No Combination), PBT(PBT), WBANDCOMB(Wideband Combination), DIVERSITY(Transmit Diversity), DDIVERSITY(Dynamic Transmit Diversity), DPBT(DPBT), DTIC(Transmit Independency or Combination), NONE(none) Actual Value Range: NOCOMB, PBT, WBANDCOMB, DIVERSITY, DDIVERSITY, DPBT, DTIC, NONE Default Value: NOCOMB Unit: None

TRXAIDSWIT BSC6900 SET GBFD-113 TRX CH GCELLCCACCE 801 Cooperation SS(Optional)

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Meaning: Whether TRX mutual aid is enabled for the BSC6900. TRX mutual aid is classified into main BCCH mutual aid and baseband frequency hopping (FH) mutual aid. If main BCCH mutual aid is enabled, the BSC6900 can switch a faulty main BCCH TRX over to a functional TRX in the cell. When the original main BCCH TRX recovers, it can be switched back based on the


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Parameter ID NE

7 Parameters

MML Command Feature ID Feature Name Description parameter setting. If baseband FH mutual aid is enabled, the BSC6900 can remove a faulty TRX from the baseband FH group to ensure the proper FH. The removed TRX will not participate in frequency hopping. When the removed TRX recovers, the BSC6900 determines whether to switch the TRX back to the baseband FH group according to the value of the "Switchback Policy of Baseband FH Mutual Aid" parameter. If the parameter is set to TRXAid_NotAllow, TRX mutual aid is not allowed. If the parameter is set to AllowReForbid, TRX mutual aid is allowed, but TRX switchback is not allowed. If the parameter is set to AllowReImmed, TRX mutual aid is allowed, and the faulty TRX is switched back immediately when conditions for TRX switchback are met. If the parameter is set to AllowReCheckRes, TRX mutual aid is allowed, and the faulty TRX is switched back when conditions for TRX switchback are met in the specified resource check period. GUI Value Range: TRXAid_NotAllow(TRX Aiding Not Allowed), AllowReForbid(Allowed & Recover Forbidden), AllowReImmed(Allowed & Recover Immediately), AllowReCheckRes(Allowed & Recover When Chk Res) Actual Value Range: TRXAid_NotAllow, AllowReForbid, AllowReImmed, AllowReCheckRes Default Value: AllowReCheckRes Unit: None

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8 Counters

8 Counters Table 8-1 Counter description Counter ID

Counter Name

Counter Description

1276071419

CELL.AIDING.BCCHAIDING

R3710:Number of GBFD-113801 Cell BCCH Mutual Aids

TRX Cooperation

1276071420

CELL.AIDING.BCCHRECOVER R3711:Number of GBFD-113801 Recoveries after Cell BCCH Mutual Aids

TRX Cooperation

1276071421

CELL.AIDING.HOPAIDING

R3720:Number of GBFD-113801 Cell Baseband Hopping Mutual Aids

TRX Cooperation

1276071422

CELL.AIDING.HOPRECOVER R3721:Number of GBFD-113801 Recoveries after Cell Baseband Hopping Mutual Aids

TRX Cooperation

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Feature ID


Feature Name

8-1


9 Glossary

9 Glossary For the acronyms, abbreviations, terms, and definitions, see the Glossary.

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9-1


10 Reference Documents

10 Reference Documents [1] BSC6900 Feature List [2] BSC6900 Optional Feature Description [3] BSC6900 GSM Parameter Reference [4] BSC6900 GSM MML Command Reference [5] BSC6900 GSM Performance Counter Reference

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10-1

TRX Cooperation(GBSS13.0 02)

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