eWSE GSM-R 5.0 BSC6000 Optional Feature Description_V1.1

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eWSE GSM-R 5.0 BSC6000

Optional Feature Description

Issue V1.1

Date 2012-06-21

HUAWEI TECHNOLOGIES CO., LTD.


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Copyright Huawei Technologies Co., Ltd. 2009. 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 commercial contract made between Huawei and

the customer. All or partial products, services and features described in this document may not be within the

purchased scope or the usage scope. Unless otherwise agreed by 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 thisdocument 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]


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Contents

1 Optional Feature ............................................................................................................................ 71.1 Network Reliability .......................................................... ................................................................. ............... 7

1.1.1 GBFD-510330 BBU Redundancy ........................................................... ................................................ 71.1.2 GBFD-510327 Single Frequency Double Coverage ................................................................ ............... 81.1.3 GBFD-117801 Ring Loop ............................................................ ........................................................... 81.1.4 GBFD-113801 TRX Cooperation ................................................................................. ........................ 101.1.5 GBFD-117401 MSC Pool .................................................................................. ................................... 111.1.6 GBFD-119701 SGSN Pool ................................................................................ ................................... 121.1.7 GBFD-116601 Abis Bypass ..................................................................................................... ............. 141.1.8 GBFD-113721 Robust Air Interface Signalling .................................................................................... 141.1.9 GBFD-113726 TC POOL .................................................................................. ................................... 151.1.10 GBFD-113724 Single Frequency TRX Redundancy ........................................................................ .. 171.1.11 GBFD-115301 Local Multiple Signaling Points ......................................................... ........................ 181.1.12 GBFD-113725 Duo-location BSC ........................................................ .............................................. 19

1.2 High Speed Coverage ................................................................. .................................................................. .. 201.2.1 GBFD-510101 Automatic Frequency Correction (AFC) ...................................................................... 201.2.2 GBFD-510102 Fast Move Handover .................................................................................................... 211.2.3 GBFD-510103 Chain Cell Handover ................................................................. ................................... 221.2.4 GBFD-510326 AFC-Based Handover Algorithms....................... ......................................................... 23

1.3 Coverage enhancement .............................................................. ................................................................. ... 241.3.1 GBFD-115901 PBT(Power Boost Technology) ............................................................ ........................ 241.3.2 GBFD-115902 Transmit Diversity .......................................................... .............................................. 241.3.3 GBFD-115903 4-Way Receiver Diversity .................................................................... ........................ 25

1.4 Enhanced Voice Service .............................................................................................. ................................... 261.4.1 GBFD-113301 Enhanced Full Rate ........................................................ .............................................. 26

1.5 Special Application and Service ............................................................ ......................................................... 271.5.1 GBFD-510104 RRU Multi-site Cell .................................................................. ................................... 271.5.2 GBFD-510328 Flat Shunting ....................................................... ......................................................... 281.5.3 GBFD-510329 Cab Radio QoS Report .............................................................. ................................... 281.5.4 GBFD-510306 Talker Identification .................................................................. ................................... 291.5.5 GBFD-510309 Group Call Reliability Enhancing ................................................................................ 30

1.6 Frequency Improving ............................................................................ ......................................................... 311.6.1 GBFD-510303 Group Channel Assignment for Active Cells ............................................................ ... 31


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1.6.2 GBFD-510304 Broadcast Channel Assignment for Active Cells....................................................... ... 311.6.3 GBFD-510323 Uplink Reply ....................................................... ......................................................... 321.6.4 GBFD-510305 Single Channel Group Call Originating ....................................................................... 33

1.7 GPRS/EGPRS Service ............................................................... ................................................................. ... 341.7.1 GBFD-114101 GPRS ........................................................ ................................................................. ... 341.7.2 GBFD-118901 CS-3/CS-4 ...................................................................... .............................................. 351.7.3 GBFD-510002 Gb Over FR ......................................................... ......................................................... 361.7.4 GBFD-510001 Network Operation Mode I .......................................................................................... 371.7.5 GBFD-114201 EGPRS ...................................................................................... ................................... 381.7.6 GBFD-113101 PDCH Dynamic Adjustment ........................................................................................ 40

1.8 EGPRS Service Enhancement ............................................................... ......................................................... 411.8.1 GBFD-119201 11-Bit EGPRS Access .......................................................................... ........................ 411.8.2 GBFD-119202 Packet Assignment Taken Over by the BTS .............................................................. ... 411.8.3 GBFD-119203 Extended Uplink TBF ......................................... ......................................................... 431.8.4 GBFD-119204 Dynamically Adjusting the Uplink MCS Coding ......................................................... 431.8.5 GBFD-119205 Dynamically Adjusting the RRBP Frequency .............................................................. 441.8.6 GBFD-119302 Packet Channel Dispatching ................................................................. ........................ 451.8.7 GBFD-119303 Load Sharing ....................................................... ......................................................... 461.8.8 GBFD-119501 Adaptive Adjustment of Uplink and Downlink Channels ......... ................................... 471.8.9 GBFD-119305 BSS Paging Coordination .......................................................... ................................... 481.8.10 GBFD-118603 Gb over IP ......................................................... ......................................................... 491.8.11 GBFD-119502 PS Handover ...................................................... ......................................................... 501.8.12 GBFD-119503 Early TBF Establishment .................................. ......................................................... 50

1.9 Cell Reselection of PS Domain ............................................................. ......................................................... 511.9.1 GBFD-116201 Network-Controlled Cell Reselection (NC2) ............................................................... 511.9.2 GBFD-116301 Intra BSC Network Assisted Cell Change (NACC) .................................................. ... 521.9.3 GBFD-119801 Packet SI Status (PSI) ................................................................ ................................... 53

1.10 CS General Enhancement ......................................................... .................................................................. .. 541.10.1 GBFD-115601 Automatic Level Control (ALC) ................................................................... ............. 541.10.2 GBFD-115602 Acoustic Echo Cancellation (AEC) ............................................................................ 541.10.3 GBFD-115603 Automatic Noise Restraint (ANR) ................................................................. ............. 551.10.4 GBFD-115701 TFO .............................................................................. .............................................. 561.10.5 GBFD-116801 Voice Quality Index (VQI) ........................................... .............................................. 571.10.6 GBFD-117501 Enhanced Measurement Report (EMR) ....................... .............................................. 571.10.7 GBFD-117101 BTS Power Lift for Handover ............................................................ ........................ 591.10.8 GBFD-115703 Automatic Noise Compensation (ANC) ........................................................ ............. 59

1.11 Network Synchronization ..................................................................................................... ........................ 601.11.1 GBFD-510401 BTS GPS Synchronization ......................................................................................... 60

1.12 Energy Saving ................................................................................................ .............................................. 61


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1.12.1 GBFD-117601 HUAWEI III Power Control Algorithm ............ ......................................................... 611.12.2 GBFD-111602 TRX Power Amplifier Intelligent Shutdown .............................................................. 621.12.3 GBFD-111603 TRX Power Amplifier Intelligent Shutdown on Timeslot Level ................................ 631.12.4 GBFD-111604 Intelligent Combiner Bypass .............................................................. ........................ 631.12.5 GBFD-111605 Active Backup Power Control ............................................................ ........................ 641.12.6 GBFD-111606 Power Optimization Based on Channel Type .......................................................... ... 651.12.7 GBFD-111609 Enhanced BCCH Power Consumption Optimization ................................................. 661.12.8 GBFD-111611 TRX Working Voltage Adjustment .................... ......................................................... 671.12.9 GBFD-111608 PSU Smart Control ....................................................... .............................................. 67

1.13 Maintainability ............................................................................................... .............................................. 681.13.1 GBFD-114701 Semi-Permanent Connection ...................................................................................... 681.13.2 GBFD-116401 End-to-End MS Signaling Tracing ................................................................ ............. 70

1.14 Power Control Algorithm ..................................................................................................... ........................ 711.14.1 GBFD-117602 Active Power Control ................................................... .............................................. 71

1.15 Handover ................................................................................................................... ................................... 721.15.1 GBFD-510501 HUAWEI II Handover............................................................................................. ... 721.15.2 GBFD-510502 Handover Re-establishment .................................................... ................................... 72

1.16 Network Security ......................................................................................................................................... 731.16.1 GBFD-113501 A5/1 and A5/2 Ciphering Algorithm ...... .................................................................. .. 731.16.2 GBFD-113503 A5/3 Ciphering Algorithm .......................................................................................... 741.16.3 GBFD-113521 A5/1 Encryption Flow Optimization ....................................... ................................... 751.16.4 GBFD-113522 Encrypted Network Management .................................................................. ............. 75

1.17 Short Message and Fax Service.................................................................................................................... 771.17.1 GBFD-113601 Short Message Service Cell Broadcast (TS23) ........................................................ ... 771.17.2 GBFD-110203 Short messageTS21,TS22) ........................................................................ ............. 781.17.3 GBFD-110204 G3 Fax TS61,TS62) ................................................ .............................................. 791.17.4 GBFD-113602 Simplified Cell Broadcast........................................................ ................................... 80

1.18 Optional Bearer Service ...................................................................... ......................................................... 811.19 VIP Service Support ............................................................................................................. ........................ 81

1.19.1 GBFD-116001 Resource Reservation .............................................................. ................................... 811.19.2 GBFD-115002 Flow Control Based on Cell Priority .......................................................................... 821.19.3 GBFD-510308 Fast Group Call Setup ................................................................................................ 83

1.20 Abis Transmission Saving .................................................................................................... ........................ 84

1.20.1 GBFD-116701 16Kbit RSL and OML on A-bis Interface ................................................................ ... 841.20.2 GBFD-118601 Abis over IP ....................................................... ......................................................... 85

1.21 IP Transmission .............................................................................................. .............................................. 861.21.1 GBFD-118606 Clock Over IP ............................................................... .............................................. 861.21.2 GBFD-118620 Clock over IP Support 1588V2 ......................... ......................................................... 871.21.3 GBFD-118605 IP QoS ............................................................... ......................................................... 89


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1.21.4 GBFD-118607 IP Performance Monitor ........................................................................................... .. 921.21.5 GBFD-118630 Ethernet OAM ............................................................................................................ 93

1.22 PS QOS ........................................................................................................................................................ 951.22.1 GBFD-119901 Streaming QoS(GBR) .............................................................. ................................... 951.22.2 GBFD-119902 QoS ARP&THP ............................................................ .............................................. 961.22.3 GBFD-119904 PS Active Package Management ................................................................................ 97

1.23 Emergency Communications ................................................... ................................................................. ... 981.24 LCS .............................................................................................................................................................. 98

1.24.1 GBFD-115401 NSS-based LCS (Cell ID + TA) .................................................................... ............. 981.24.2 GBFD-115402 BSS-based LCS (Cell ID + TA) .............................................. ................................... 981.24.3 GBFD-115403 Simple Mode LCS (Cell ID + TA) ............................................................................. 99

Acronyms and Abbreviations .................................................................................................... 100


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1 Optional Feature1.1 Network Reliability

1.1.1GBFD-510330 BBU Redundancy

Availability

This feature is available from GSM-R 3.1.

Summary

One RRU is connected to the active and standby BBUs at the same time, but communicates

with only one BBU at a special time.

Benefits

This feature improves the reliability of network devices and prevents the single point failure.

Description

A group of RRUs are connected to the active and standby BBUs. To be specific, one RRU is

connected to two BBUs. Under normal circumstances, the RRU communicates with only the

active BBU. In addition, the RRU supports the CPRI switchover. When the active BBU is

faulty, the BSC performs switchover on the active and standby BBUs. The RRU, in turn,triggers the CPRI switchover. After the CPRI switchover, the RRU communicates with the

current active BBU.

The causes of the switchover of the active and standby BBUs are as follows:

The active BBU is faulty.

The OML corresponding to the active BBU is faulty.

The resource utilization of the active BBU changes.


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In addition, the active and standby BBUs can be installed in two base stations to provide theBBU redundancy function as well as the transmission backup function.

1.1.2GBFD-510327 Single Frequency Double Coverage

Availability


Summary

Two base stations are deployed at the same site to provide network coverage for the same area.The two base stations work in active/standby mode and operate at the same frequencies. Onlyone base station works at a time, and this base station is considered as the active base station.

Under normal circumstances, the active base station is functional, and the standby base station

is powered on but its TRXs do not transmit or receive any signals. When a TRX of the active

base station is faulty, the TRX of the standby base station is activated to replace the faultyTRX. The substitute TRX operates at the same frequency used by the faulty TRX.

Benefits

The two co-sited base stations work in active/standby mode to ensure thatcommunication is not affected even if one base station is faulty.

This feature applies to the railway network scenario where the frequency resources areinsufficient and the redundancy coverage is required. It improves the network reliability,

simplifies frequency planning, reduces handovers, and improves network performance.

DescriptionThe working principle of this feature is as follows: On the BSC side, the active/standby mode

is configured for the two co-sited base stations. Under normal circumstances, the active base

station is functional, and the standby base station is powered on but its TRXs do not transmit

or receive any signals. When the active base station is faulty or a TRX of the active basestation is faulty, the active base station sends a message to the BSC to notify the BSC of the

fault. The BSC then sends a command to the standby base station. On receiving the commandfrom the BSC, the TRXs of the standby base station start to transmit and receive signals. Afterthe standby base station is functional, the BSC sends a message to the active base station,

instructing the active base station to stop transmitting and receiving signals. The switchover isperformed on the whole active and standby base stations when the related conditions are met.

1.1.3GBFD-117801 Ring Loop

Availability

This feature is available from GSM-R 1.0


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Summary

The ring topology is a special chain topology. Several BTSs form a chain, and the

lowest-level BTS is connected to the BSC through the transmission link, thus forming a ring.If there is a breakpoint on the ring, the BTSs that precede the breakpoint remain unchanged in

networking mode whereas the BTSs that follow the breakpoint form a new chain connectionin the reverse direction.

the ring network switchover is accelerated and the BTS need not be initialized in the reversering direction. Thus, the call drops due to the ring network switchover and the impact of the

switchover on the new calls are reduced.

Benefits

Compared with the ordinary chain topology, the advantage of the ring topology is that when a

connection is broken, the ring automatically breaks into two chains. In this way, the BTSs thatprecede and follow the breakpoint can work normally, thus improving the robustness of the

system.

Fast loop switcher reduces the impact of the ring network switchover on the services, thus

increasing the network reliability and improving the user satisfaction.

Description

The ring topology supports the following operations:

Automatic switchover

Manual switchover

Querying and dynamically configuring of the switchover parameters

Dynamic data configuration such as adding or deleting a BTS, cell, or TRX.

Figure 1-1 and Figure 1-2 show the ring topologies of the BTS:

Figure 1-1Ring topology (1)


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Figure 1-2Ring topology (2)

Numbers 0 and 1 shown in Figure 1-1 refer to port 0 and port 1 of the BTS. In the BTS ring

topology, the link established at port 0 is a forward link and the link established at port 1 is areverse link.

The BTS ring topology can be implemented between interface boards but not betweensubracks. In other words, the BTS ring topology must be implemented between the GEIUBs

located in the same subrack, as shown in Figure 1-2.

Generally, the BTS ring topology is a chain of BTS0, BTS1, and BTS2 in sequence, known as

a forward direction. In the forward direction as shown in Figure 1, BTS0 is the highest-levelBTS, BTS1 is the second-level BTS, and other BTSs are connected analogically. When thelink A, B, C, or D is broken, the BTSs that precede the breakpoint remains in the same

topology, and the BTSs that follow the breakpoint form a chain in a reverse direction.

The BTS ring topology is categorized into two types: Huawei BTS ring topology I and

Huawei BTS ring topology II. In BTS ring topology I, the BTS with a reverse link isinitialized again after transmission disruption, and thus the services of the BTS are disrupted.

In BTS ring topology II, the services of the BTS with a reverse link are not disrupted aftertransmission disruption.

When the Fast Ring Network Switch feature is enabled, the ring network switchover isaccelerated and the BTS need not be initialized in the reverse ring direction. Thus, the call

drops due to the ring network switchover and the impact of the switchover on the new callsare reduced. Thus, the network reliability is increased and the user satisfaction is improved.

1.1.4GBFD-113801 TRX Cooperation

Availability



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Summary

With this feature, when the BCCH TRX is faulty, the cell automatically rectifies the faults.

Thus, the services in the cell are not affected before the faulty TRX is replaced.

Benefits

The TRX Cooperation feature ensures that the cell provides services continuously. This

feature reduces the probability that the cell is out of service because of the faulty BCCH TRX.

Thus, the reliability of the network is greatly improved.

Description

In the idle state, the MS needs to obtain information through the broadcast messages senton the BCCH. The messages carry information about cell selection, adjacent cell, access

control, dedicated channel control, cell identification code, location, and systemparameters related to the PS services. When a BCCH TRX of a cell is faulty, all the

services in this cell are interrupted. Therefore, when the BCCH TRX is faulty, anotheravailable TRX of the cell is used to substitute the faulty BCCH TRX to ensure that the

cell can continue to provide services. After the fault in the original BCCH TRX is

rectified, the BSC can switch the BCCH back to the original TRX. This process is calledBCCH TRX cooperation.

1.1.5GBFD-117401 MSC Pool

Availability


Summary

With this feature, multiple MSCs form a resource pool to provide services for the subscribers

belonging to one group of BSCs.

Benefits

The MSCs in an MSC pool share the traffic load and resources. Therefore, this feature

provides the following benefits:

This feature increases the network capacity and saves the equipment investment.

This feature realizes the redundancy backup and thus improves the network reliability

because the addition or deletion of an MSC does not affect the services.

This feature automatically adjusts the traffic load on an MSC and reduces the operation

and maintenance cost of operators.

The MSC pool is logically an MSC. Therefore, the number of handovers between MSCsis reduced and the network performance is improved.


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Description

With this feature, a maximum of 32 MSCs form a resource pool to provide services for the

subscribers under one group of BSCs. Through the MSC pool, one BSC can be connected tomultiple MSCs simultaneously. In addition, the traffic on the BSC is evenly distributed to the

MSCs in the pool according to the NRI or load balancing principle. The following figureshows the typical networking of the MSC Pool feature:

In the preceding figure, MSC 1, MSC 2, and MSC 3 form an MSC pool. All the CS services

or PS services in the BSC service areas (Area 1, Area 2, Area 5, and Area 6) are routed to theMSC pool for further processing. The routing policies are described as follows:

Routing by network load

For the newly-registered MS, the BSC selects an MSC by using the load balancing

algorithm based on the IMSI carried in the CMP L3 message, the status of MSCs in theMSC pool, and the available capacity. Then, the BSC directs the traffic of the MS to the

selected MSC for processing.

If the MS without the SIM card initiates an emergency call, the BSC selects the MSCbased on the IMEI, the status of MSCs in the MSC pool, and the available capacity and

then directs the traffic of the MS to the selected MSC for processing.

Routing by the NRI

After the MS is registered, the MSC allocates the TMSI containing the NRI to the MS.The NRI is used for identifying an MSC in the MSC pool. During the call processing,

the MS sends the TMSI to the network side. On receiving the TMSI, the BSC resolvesthe NRI from the TMSI and then directs the traffic to the MSC based on the MSC

signaling point corresponding to the NRI in the configuration data.With this feature, the BSCs in the pool area share a group of MSCs. If heavy traffic

hours of each BSC are different, less CN resources are required compared with thenetwork where the MSC Pool feature is disabled. This saves the investment in the CN

equipment.

When an MSC in the MSC pool is faulty, the traffic of the newly accessed MS is

automatically directed to another normal MSC, thus enhancing the network reliability.When some maintenance operations such as software upgrade are performed on an MSC

in the MSC pool, the traffic on this MSC can be easily directed to other MSCs. After theoperation is complete, the traffic is reallocated to the original MSC. This reduces the

service interruption duration and thus improves the user satisfaction.

1.1.6GBFD-119701 SGSN Pool

Availability



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Summary

With this feature, multiple SGSNs form a resource pool to provide services for the subscribers

belonging to one group of BSCs.

Benefits

The SGSNs in an SGSN pool share the traffic load and resources. This feature provides the

following benefits:

Increases the network capacity and saves the investment on equipment.

Implements redundancy backup and thus improves the network reliability because the

addition or deletion of an SGSN does not affect the services.

Reduces handovers between the SGSNs because the SGSNs in an SGSN pool are

logically one SGSN and thus improves the network performance.

DescriptionThis feature, which is similar to the MSC Pool feature, enables a maximum of 32 SGSNs to

form a resource pool to provide services for the subscribers belonging to one group of BSCs.

With this feature, one BSC can be connected to multiple SGSNs at the same time. In addition,the traffic on the BSC is evenly distributed to the SGSNs in the pool according to the network

resource identifier (NRI) or load balancing principle.

The routing policies are described as follows:

Routing by network loadWhen an MS accesses the network for the first time, it generates a random TLLI and

sends it to the BSC because it does not have a local/foreign TLLI. Then, the BSC usesthe load balancing algorithm to select an SGSN for the MS according to the status and

available capacity of the SGSNs in the pool and routes the MS to the selected SGSN.

Routing by the NRI

After an MS accesses the network for the first time, the SGSN allocates a new localTLLI that includes the NRI information associated with this SGSN to the MS. When the

MS processes services, it sends the NRI information to the network through the

local/foreign TLLI. Then, the BSC obtains the NRI from the local/foreign TLLI androutes the services to the SGSN corresponding to the NRI in the configuration data.

Using the SGSN pool, the BSCs in the pool share a group of SGSNs. If peak hours oftraffic on each BSC are different, less CN resources are required in comparison with thenon SGSN pool networking. This saves the investment on the CN equipment.

When an SGSN in the SGSN pool is faulty, the new services are automatically

transferred to another normal SGSN and thus the network reliability is enhanced. When

some maintenance operations such as software upgrade are performed on an SGSN inthe SGSN pool, the traffic on this SGSN can be easily transferred to other SGSNs. After

the operation is complete, the traffic is reallocated to the original SGSN. This reduces theservice interruption duration and thus improves the user satisfaction.


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1.1.7GBFD-116601 Abis Bypass

Availability


Summary

In the case of chain topology, when the power supply to a BTS fails, this feature can bypass

this BTS (that is, this BTS is used only as the path) so that the signals of the lower-level BTSs

can be sent to the BSC.

Benefits

In the chain topology, if the power supply to the upper-level BTS fails, the transmission of the

lower-level BTSs cannot proceed normally. With this feature, the lower-level BTSs can work

normally even if the power supply to the upper-level BTS fails. Thus, this feature provideshigher reliability for the network in the chain topology, especially in the areas where thepower supply fails frequently.

Description

To improve the working capability of the BSS system in the areas where the power supply

fails frequently, Huawei BTS provides the Abis Bypass feature. This feature is applicable inthe case of chain topology. When the power supply to a BTS fails, the BTS automatically

bypasses the Abis interface so that the lower-level BTSs in the chain network can work

normally. When the power supply is recovered, the BTS and the lower-level BTSs are resetautomatically.

1.1.8GBFD-113721 Robust Air Interface Signalling

Availability


Summary

With this feature, the FACCH frames and SACCH frames are sent repeatedly when the radio

quality is poor. Thus, this feature enhances the anti-interference capability of the signaling

links on the FACCH and SACCH and increases the possibility that the MS and the BSCsuccessfully receive the signaling messages. This feature involves repeated sending ofdownlink FACCH frames and repeated sending of uplink/downlink SACCH frames.

Benefits

This feature provides the following benefits:


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Repeated sending of FACCH frames improves the FACCH link performance of theordinary MS by 2 dB and the FACCH link performance of the MS in R6 version by 4 dBto 5 dB.

Repeated sending of SACCH frames improves the SACCH link performance of the

ordinary MS by 4 dB to 5 dB. The improvement in the FACCH and SACCH performance reduces call drops and

increases the accuracy of the handover decision and power control decision of the BSC.

Description

In the network with tight frequency reuse and poor radio transmission performance, the

messages sent through the FACCH frames or the SACCH frames may be lost because of thehigh bit error rate on the Um interface. This feature consists of repeated sending of downlink

FACCH frames and repeated sending of uplink/downlink SACCH frames.

Repeated sending of downlink FACCH frames

When the receive quality in the downlink measurement report is lower than the specifiedthreshold, the BTS determines whether to resend the FACCH frames. The repeatedsending of downlink FACCH frames can increase the possibility that the MS

successfully receives the signaling messages.

Repeated sending of uplink/downlink SACCH frames

If the BTS detects that the SACCH frames are incorrectly decoded, it instructs the MS toresend the recent SACCH frame. If the MS detects that the SACCH frames are not

correctly decoded, it instructs the BTS to resend the recent SACCH frame.

With this feature, the voice quality is slightly affected because the signaling messages are sent

through frame stealing.

When the radio quality is poor, repeated sending of signaling messages in the downlink can

reduce call drops caused by decoding failure. Repeated sending of signaling messages in theuplink can increase the accuracy of the handover decision and power control decision of the

BSC by increasing the possibility of correctly decoding the uplink measurement reports.

1.1.9GBFD-113726 TC POOL

Availability


Summary

With this feature, multiple BSCs share the same TC resources in the TC pool. This increases

the efficiency of the codec hardware.

Benefits

The efficiency of the codec hardware is increased because multiple BSCs share the same


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resources in one TC pool. For the small-capacity BSC, 20% to 30% TC codec resources

can be saved.

Saving roomage is possible.For example, three small-capacity GTCSs require three

cabinets. In TC pool mode, three GTCSs require only one cabinet. In this manner, 40% to

60% area in the equipment room can be saved.

Description

In general, one GTCS belongs to only one BSC and is used to process the CS services of this

BSC. The GTCSs in different BSCs are not associated with each other. In this kind of networktopology, the TC resources cannot be multiplexed among multiple BSCs. In the scenario wheremultiple BSCs with small capacity are grouped into a network, the TC resources are greatlywasted.

In TC pool mode, multiple BSCs share a TC pool of large capacity. The typical networktopology is shown in the following figure.

E1/STM-1

E1/STM-1

E1/STM-1

E1/ST

M-1

E1/STM

-1

E1/STM-1

The TC pool adapt to the mode that the GTCS is separated from the BSC cabinet and is

connected to the BSC through the Ater interface. The codec resources in the TC pool areshared by the main BSC and sub-BSCs, which work in load sharing mode. When a voice

processing board is faulty, it will out of service automatically. In this manner, the subsequentCS services are not affected, which improves the system reliability. The speech versionssupported by the TC pool are FR, EFR, HR, AMR-FR, and AMR-HR.

To synchronize the clock of the GSM network, the main BSC and sub-BSCs in a TC poolshould use the same clock source. In addition, a BSC can be connected to only one TC pool.

One TC pool supports a maximum of 16 BSCs.


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1.1.10 GBFD-113724 Single Frequency TRX Redundancy

Availability


Summary

Huawei BTS is able to provide TRX redundancy, i.e. the standby transceivers can take over

the work of active ones with the same ARFCN, as soon as the active transceivers fail.

Inside a same DTRU board, 1 TRX can act as backup for the other TRX

Between different DTRU boards, the TRX of one DTRU can act as backup for the TRX

of another DTRU.

Benefits

The failure of one TRX will not affect the coverage and capacity of the network.

This feature improves the reliability of the network and removes a single point of failure.

Description

In normal operating conditions, the active TRXs work for the network coverage and providethe required capacity. When an active transceiver fails, the BTS automatically activates the

relative standby TRXs so as to replace the failed TRX: the newly-activated standby TRX will

use the same frequency as the failed TRX. Therefore, although ongoing calls on the failedTRX are dropped, the capacities of the cell and the access to the GSM-R services are fully

recovered within 30 seconds.

The TRX recovery within one DTRU is 30 seconds, the TRX recovery between differentDTRUs is 2 minutes.

The two modes (Intra-DTRU and Inter-DTRU) of the TRX redundancy can not exist inside

one BTS.

The number of master TRX and the number of redundancy TRX must be equal.

The figure below explains the network architecture of this feature:


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1.1.11GBFD-115301 Local Multiple Signaling Points

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Summary

With this feature, a physical node is logically classified into multiple signaling points. Each

signaling point can be independently connected to other signaling points.

Benefits

This feature breaks the capacity limitation of a single signaling point using the narrowband

signaling.

Description

With this feature, a physical node is logically classified into multiple signaling points. Each

signaling point can be independently connected to other signaling points. If a physical node islogically classified into N signaling points, the number of links between this physical node

and the remote signaling point is extended to N x 16 because the maximum number ofsignaling links between the OSP and DSP is 16. This feature breaks the limitation of 16

signaling links of a single signaling point using the narrowband signaling and thus meets thesignaling link requirements for large capacity processing of the BSC6000.

In addition, the requirements for the signaling networking capability of the CN are reducedbecause the high-speed signaling technology is not used.

1.1.12GBFD-113725 Duo-location BSC

Availability


Summary

This feature enables 2 BSCs (a master and a slave) to be connected to the same MSC/SGSNand to the same set of BTSs, but one BSC is active and the other one is not active. In normal

operating conditions, only the master BSC provides the communication service; the slaveBSC only provides a physical connection. If the active BSC fails, the other BSC

automatically takes over the provision of the communication service.

Benefits The two BSCs work in active/standby mode to ensure that access to the GSM-R service

is restored as soon as possible in the event of the active BSC breaking down.

This feature improves the availability of the GSM-R network and removes a single point

failure.

Description

The master and slave BSCs are connected to the same MGW, the same SGSN and the same

BTSs. In normal conditions, it is the responsibility of the master BSC to perform the usualBSC functions for the BTS and for the Core network. The master BSC keeps in touch with theslave BSC via a heartbeat signal sent through MTP through the MSC server.


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If the master BSC fails (BSC failure causes include failure of the BSC node itself but alsofailure of the A interface), the slave BSC takes over full control of the BTS and begins tointeract with the Core network. All ongoing calls are dropped but access to the GSM-R

service is restored automatically for new calls in a matter of a few minutes, thus greatlyenhancing the network availability. The service will be affected for less than 5 minutes.

The data synchronization between master and slave BSC is done by the CME and MML of

M2000.

The figure below explains the network architecture of this feature:

1.2 High Speed Coverage1.2.1GBFD-510101 Automatic Frequency Correction (AFC)

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Summary

The automatic frequency correction (AFC) feature uses a special balancing algorithm to

estimate the difference between the standard frequency and the frequency of theGMSK-coded signal sent from the fast-moving MS to the BTS. The AFC estimates the

frequency offset between the frequency of each received burst and the standard frequency inreal time. Then, the estimated frequency offset is used to correct the RX working frequency of

the BTS.

Benefits

This feature improves the decoding performance of the physical link in the uplink in the fast

moving condition, thus ensuring the physical transmission performance and reliableconnections between the fast-moving MS and the BTS. In addition, this feature enables the

system to support a telecommunication environment with a speed higher than 500 km/h,which serves as the basis of the high-speed frequency offset handover algorithm.

Description

AFC is a BTS frequency correction algorithm designed for fast-moving MSs. This algorithm

ensures reliable radio links and continuous services with good voice quality when the MSmoves at a speed of 500 km/h.

According to Doppler frequency shift principle, the frequency of the signals sent by thefast-moving MS shifts. The frequency shift information is related to the moving speed and

direction of the MS relative to the BTS. The BTS digital signal processor uses a special

balancing algorithm to estimate the difference between the standard frequency and thefrequency of the GMSK-coded signal sent from the fast-moving MS to the BTS. The AFC

estimates the frequency offset between the frequency of each received burst and the standard

frequency in real time. Then, the estimated frequency offset is used to correct the RX workingfrequency of the BTS. This improves the decoding performance of the physical link in the

uplink in the fast moving condition, thus ensuring the physical transmission performance andreliable connections between the fast-moving MS and the BTS.

The performance of AFC depends on the vertical distance between the BTS and the railway.The shorter the vertical distance is, the faster the change of the frequency offset is when thetrain approaches the BTS. Therefore, the AFC loop cannot keep pace with the change of

frequency offset, leading to a great residual frequency offset.

Simulation results show that the frequency offset smaller than 100 Hz has little impact on thedemodulation performance. Therefore, when the TRX is on the GSM900 band and the speed

of the train is 600 km/h, only the vertical distance of more than 100 m is supported if the loop

bandwidth is 2 Hz. In the case of a lower demand for the voice quality, the vertical distancebetween the BTS and the railway can be shorter.

1.2.2GBFD-510102 Fast Move Handover

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Summary

This feature enables better cell handover in a short period of time.

BenefitsGenerally, the chain cell algorithm is not used because of the special characteristics of the

railway and highway users. This may lead to slow handover or call drops during handover.With this feature, the handover success rate in the fast-moving condition is increased and thus

the subscriber satisfaction is increased.

Description

In a fast-moving train, it takes a short time for an MS to move across a cell. Therefore, ahandover must be performed quickly. To reduce the handover failure rate, a handover must be

quickly initiated when required. If the handover fails (for example, when the radio interfacesuddenly incurs interference), a second handover must be quickly initiated.

The fast PBGT handover algorithm enables better cell handover in a short period of time.Compared with the existing PBGT handover algorithm, the fast PBGT handover algorithm

has the following advantages:

Handing over an MS to a proper target cell by predicting the moving direction of the MS

Accelerating the handover decision to improve the handover rate

1.2.3GBFD-510103 Chain Cell Handover

Availability


Summary

This feature enables the fast-moving MS to be preferentially handed over to the chain

neighboring cell.

Benefits

This feature increases the handover success rate in the fast-moving condition and thus

increases the subscriber satisfaction.

Description

By predicting the moving direction of a fast-moving MS, this feature enables the fast-moving

MS to be handed over between two chain neighboring cells. Thus, the handover success rateis increased and the network quality is improved. Chain neighboring cells ensure reliable

handovers between cells.

Chain neighboring cells are formed on the basis of the linear coverage characteristic ofthe fast-moving environment such as the railway.


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A handover to a chain neighboring cell is preferred. In addition, handover to the movingdirection of the user should be guaranteed.

1.2.4GBFD-510326 AFC-Based Handover Algorithms

Availability


Summary

The AFC-Based Handover Algorithm acts as an algorithm that quickens the handover

decision, it is based on AFC.

BenefitsThe AFC-Based Handover Algorithm is used in the application scenarios of high-speed

mobile communications. It quickens the handover decision, shortens the handover area, andimproves the inter-cell handover performance. When moving at a high speed, the MS canperform a second handover if the first handover fails in a limited handover area.

Description

According to the Doppler frequency offset principle, frequency offset occurs when an MS

moves at a high speed. The frequency offset is related to the movement speed and direction of

the MS against the BTS.

The AFC-Based Handover Algorithm adopts the obtained information about the movementspeed and direction of an MS against the BTS from the AFC algorithm. It improves thehandover decision algorithm and shortens the handover decision time when an MS moves at a

high speed. Thus the MS completes the handover in a limited handover area (overlapped

coverage area of neighboring cells) or shrinks the handover area.

The BTS calculates the frequency offset value in real time, packs the value in the

measurement report message, and sends the message to the BSC. The BTS calculates thefrequency offset value of each received burst, so the frequency offset value can be updated in

real time.

Based on the frequency offset f, if the absolute value of the MS movement speed is less

than a preset value (the MS is regarded to be in slow movement or at rest), the commonhandover decision algorithm of the original GSM system is adopted. If the absolute value is

greater than or equal to the preset value, the AFC-Based Handover Algorithm is adopted.

According to the measurement report delivered by the MS, do as follows if the signal quality

of a certain neighboring cell (generally only one neighboring cell owing to linear coverage) isbetter than that of the current cell:

1. When the frequency offset f of the MS is a negative number (indicating that the MS is

moving away from the BTS), trigger the handover immediately if the P/N rule is met.


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2. When the frequency offset f of the MS is a positive number (indicating that the MS isgetting close to the BTS), the handover is not triggered.

The algorithm is based on the characteristics (handover is performed only from one cell toanther one and only cell) of linear coverage along the railway or highway.

1.3 Coverage enhancement

1.3.1GBFD-115901 PBT(Power Boost Technology)

Availability


Summary

The Power Boost Technology (PBT) enables the DTRU to transmit the combined signals with

high gain and to achieve extended network coverage.

Benefits


This feature can realize the mutual transformation between the network coverage and thenetwork capacity.

In the initial network deployment stage, the operators can use the PBT to extend the

network coverage, thus reducing the number of BTSs.

When the subscriber number increases and the network capacity needs to be expanded,

operator can transform the PBT-enabled single TRX into two common-mode TRXs, thusprotesting the hardware investment.

Description

In the DTRU, two TRXs are integrated into a TRX module that is configured with a combiner.The combiner combines the radio signals of the same frequency and same phrase from twoTRXs, and then transmits the combined signals. In this way, the downlink transmit power is

higher than the transmit power of the original signals, and the transmit power with high gainis achieved and the downlink coverage is extended.

1.3.2GBFD-115902 Transmit Diversity

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Summary

To enable this feature, the two TRXs in the DTRU are connected to the two separated antenna

feeders respectively, and the two antennas transmit the same downlink signal on the samefrequency. Through the introduction of the controllable delay and changeable phase between

two signals of the two TRXs, the diversity gain in terms of time and space can be obtained,thus enhancing the RX signals and reducing the signal attenuation. This in turn, extends the

network coverage.

Benefits


This feature can realize the mutual transformation between the network coverage and thenetwork capacity.

This feature can effectively extend the downlink coverage, thus reducing the number ofrequired BTSs.

When the requirement for the network coverage decreases and the requirement for the

capacity increases, operator can transform the transmit diversity-enabled single TRX into

common-mode TRXs.

Description

The feature enables the two TRXs that are integrated in the DTRU to transmit the correlated

signals on the same frequency. This provides two independent downlink multi-path signals,

and these signals are processed by the equalizer of the MS. In this way, the diversity gain isobtained, and the quality of the RX signal is improved. Therefore, the downlink coverage is

improved. If the DTRU works in single TRX mode, this feature can be enabled throughremote data configuration.

1.3.3GBFD-115903 4-Way Receiver Diversity

Availability


Summary

The 4-way receiver diversity technology allows four antennas (four uni-polarized antennas or

two dual-polarized antennas) to receive the muti-path uplink signals from one cell. Then thereceived signals are combined. Compared with two-way receiver diversity, four-way receiverdiversity can improve the receive sensitivity, thus extending the uplink coverage.

Benefits

The 4-way receiver diversity technology can enhance the uplink RX signal strength by

increasing the receive gain of the BTS antennas without increasing the transmit power of theMS. In this way, the cell coverage is extended and the improved QoS can be achieved.


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Description

The coverage of a cell is determined by the transmit power of the BTS and MS, and the

receive gain of the BTS antenna. Because the transmit power of an MS is much lower thanthat of a BTS, in most cases, the actual coverage is lower than the designed value and the

voice quality deteriorates.

With appropriate design, the 4-way receiver diversity technology allows one TRX module to

receive the uplink signals from four RX channels and then combine the uplink signals toachieve better signal quality and demodulation performance. Thus, the receive sensitivity is

improved, and the receive effect is much better than that of none receiver diversity and that of

two-way receiver diversity.

1.4 Enhanced Voice Service

1.4.1GBFD-113301 Enhanced Full Rate

Availability


Summary

The enhanced full rate (EFR) is an improved speech coding scheme. The quality of the speech

using EFR is better than that of the speech using FR.

BenefitsThe user experience is improved because the voice quality in the EFR that uses the FR

channel resource approaches or even exceeds the voice quality in the ADPCM.

Description

The EFR is an improved speech coding scheme, which works at the rate of 12.2 kbit/s. The

quality of the voice using the FR channel resource in the EFR scheme approaches or even

exceeds the voice quality in the ADPCM scheme.

The EFR has good anti-noise performance. If the quality of the Um interface is good, you canobtain the voice quality as good as the voice quality of the traditional wired telephone even if

there is a lot of background noise. Therefore, in the same air conditions, the subscriber canperceive a better voice quality in the EFR than in the FR. In addition, the rate of the EFR islower than that of the FR (13 kbit/s). Thus, the BER sensitivity of EFR is lower than that of

FR. In this manner, the data can be transmitted more reliably on the Abis interface, which

further improves the voice quality.


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1.5 Special Application and Service

1.5.1GBFD-510104 RRU Multi-site Cell

Availability


Summary

This feature enables the subsites in different physical sites to be set to a logical cell, which isalso called a cascading cell. A subsite refers to a certain area physically covered by multiple

RRU/RFUs that belong to the same BBU. In the scenarios such as railway, tunnel, or indoor

coverage, a cascading cell can reduce handovers, improve the coverage efficiency, andenhance the user experience.

Benefits


This feature reduces handovers between cells and increases the handover success rate.

A cascading cell increases the effective coverage distance of each subsite and improves

the coverage efficiency of the entire cell because few handover areas are required

between different subsites.

Description

Cell cascading means that different subsites in the same BBU physically belong to differentsites but logically belong to the same cell. The principle is shown in the following figure.

Cascading cells are carried in multiple subsites. These subsites have the same cell parameterssuch as physical configurations, the number of TRXs, and frequencies. One cascading cell hasonly one primary subsite responsible for cell management and service control. Other subsites

are secondary subsites. Under the control of the primary subsite, these secondary subsitesimplement cell service functions such as the selection of available TRXs and the activation of

channels.

During the initial access of an MS, all the subsites calculate the uplink signal noise ratio (SNR)of the MS respectively and report the result to the primary subsite. Then the primary subsiteselects the subsite with the optimal SNR as the serving subsite.

All the subsites continuously calculate the uplink SNR of the MS and then report the SNR tothe primary subsite. When the SNR reported by an adjacent subsite is better than the SNR

reported by the serving subsite, the handover between subsites is triggered. When the MS is

handed over between subsites, the new subsite is connected and then the old subsite isdisconnected without the interruption of services. In this manner, seamless handover is

implemented and the QoS is guaranteed.


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1.5.2GBFD-510328 Flat Shunting

Availability


Summary

This feature enables the simultaneous transmission of the Voice Group Call Service (VGCS)

and the CSD data.

During a VGCS call, every participant can send short data (that is, flat shunting data) to otherparticipants without affecting the VGCS call.

Benefits This feature helps to implement the special services in the railway network scenario.

This feature enables the flat shunting data to be transmitted without interrupt the VGCS.

This feature ensures the transmission of the flat shunting data. The delay of the flatshunting data is shorter than 500 ms.

Description

The working principle of this feature is as follows: The talker of the VGCS call occupies adedicated channel. The other participants send short data in the uplink of the group callchannel, and the talking of the speaker is not affected. That is, the CSD can be performed

without affecting the VGCS.

During the group call, the participants of the VGCS call can press a pre-defined key to sendthe short data to other participants.

The data is sent on all group call channels of the VGCS call and on the FACCH of the

dedicated channel of the speaker. The data is sent to all other participants of the VGCS call.After being parsed, the short data is displayed on the screen of the terminal of the participants.

1.5.3GBFD-510329 Cab Radio QoS Report

Availability


Summary

This feature enables the traffic statistical results of the 8 W cab to be obtained on the basis of

Circuit Switched Data (CSD) and speech service.

Benefits This feature facilitates obtaining the traffic statistical results in a specific manner.

Through this feature, the CSD traffic statistical results of the 8 W cab, the speech service


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statistical results of the 8 W cab, and the speech service statistical results of the 2 Woperational radio can be obtained separately.

The separated traffic statistical results assist in the assessment of the network quality and

in network optimization.

Description

The train crew members use two types of radio terminals: 2 W operational radios (handheld

devices) and 8 W cab (installed in the locomotive). The 2 W operational radios are used for

speech communication. The 8 W cab is divided into two types on the basis of functions:speech terminal and CSD terminal.The speech terminal is used for speech communication,and the CSD terminal is used to transmit train control signals.

The traffic statistical results of the 8 W cab (consisting of the CSD traffic statistical resultsand the speech service statistical results) are used to assess the quality of the GSM-R network

for the high-speed railway. The traffic statistical results of the 8 W cab can be obtained asfollows:

(1) Obtain the classmark information about the radio terminal to check whether the radioterminal is an 8 W cab.

(2) Check whether the service belongs to the CSD service according to the service type.

(3) When the "8 W Traffic Statistics Switch" parameter is set to ON, the results of the newtraffic statistical items are obtained. The measurement points of the new traffic statistical

items for the 8 W cab are the same as the measurement points of the related traffic statisticalitems for the radio terminals (including 8 W and 2 W).

In addition, the new traffic statistical items for the 8 W cab are not changed.

1.5.4GBFD-510306 Talker Identification

Availability


Summary

During a VGCS/VBS call, the real-time information of the current talker is displayed on eachMS of the subscriber involved in the call.

BenefitsIt enables the MSs involved in a VGCS call to display the information regarding the talker

such as telephone number, subscriber name, and priority within the group. In this way, thegroup members can obtain the real-time information of the current talker and determinewhether to initiate PTT preemption within the group.


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Description

Like the function of Calling Name Identification Presentation (CNIP), talker identification

allows the information of the current talker to be displayed in real time on the MSs in theVGCS/VBS. The information includes telephone number (subscriber name in the phonebook)

and priority.

During a VGCS/VBS call, the network side periodically broadcasts the talk information

including the MSISDN of the talker and the priorities of group members in the cell within thecoverage area. After receiving the information, the MSs of other subscribers display the

information of the current talker, including the MSISDN (or subscriber name in the

phonebook) and priority in the group. After the talker terminates the conversation, thenetwork side broadcasts the information periodically without the content of the talker andthen other group members remove the information displayed on the MSs.

1.5.5 GBFD-510309 Group Call Reliability EnhancingAvailability

This feature is introduced in GSM-R 5.0.

Summary

When the BTS is disconnected from the network, the BTS still supports the VGCS/VBS calls

for specified fixed group numbers within the coverage area.

Benefits

Based on this feature, when the BTS is disconnected from the network due to accident ordisaster, operators can still provide VGCS/VBS service in the area covered by the BTS, thus

enhancing user experience and brand image of the product.

Description

In addition to the system-specific reliability mechanisms such as active/standby switchover

and resource pool, Huawei GSM-R VGCS/VBS also provides fail soft capability for the

VGCS/VBS feature to improve its reliability.

After the BTS is disconnected from the network, the BTS works in fail soft mode and

supports the VGCS/VBS within the coverage area. A single cell or several cells can beconfigured under a BTS. The BTS automatically switches to normal working mode after the

transmission recovers

In fail soft mode, Huawei GSM-R supports the regular call initiation. The BTS initiates a

VGCS call that is fixedly configured once the transmission is disrupted. Then, the subscriberscan seize the uplink to talk to the subscribers in other groups within the coverage area of theBTS. The VGCS call, however, cannot be stopped so that the calls with high priority can be

set up automatically once the transmission is disrupted.


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1.6 Frequency Improving

1.6.1GBFD-510303 Group Channel Assignment for Active Cells

Availability


Summary

After a VGCS call is established, if no group member involved in the call is in the cell withinthe predefined coverage area, the VGCS traffic channel is not assigned. If a group member

accesses the cell during the VGCS call, then the network side assigns a traffic channel for the

call.

BenefitsThis feature effectively saves the radio channel resources when operators promoteVGCS-based services.

Description

During VGCS, the voice of the talker is sent to other group members through the VGCS

channel of the cell. If no group member involved in the call is in the cell within the coveragearea, the VGCS channel is actually idle.

With this feature, the network side sends a VGCS call notice periodically in each cell withinthe coverage area and the cell in which group members exist receives the response of the MS.

Then, the network side assigns a VGCS channel for the cell and notifies the group membersto join the VGCS call. The cells that do not respond are not assigned VGCS channels.

In addition, the network side periodically detects the MSs of all the cells within the coveragearea. If no group member involved in the VGCS call exists in a cell due to some reason, for

example, outgoing cell handover, the network side releases the VGCS channel assigned to thecell.

1.6.2GBFD-510304 Broadcast Channel Assignment for ActiveCells

Availability


Summary

After a VBS call is established, if no group member involved in the call is in the cell within

the predefined coverage area, the VBS traffic channel is not assigned. If a group memberaccesses the cell during the VBS call, then the network side assigns a traffic channel for thecall.


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Benefits

This feature effectively saves the radio channel resources when operators promote VBS

-based services.

Description

During VBS, the voice of the talker is sent to other group members through the VBS channel

of the cell. If no group member involved in the call is in the cell within the coverage area, the

VBS channel is actually idle.

With this feature, the network side sends a VBS call notice periodically in each cell within the

coverage area and the cell in which group members exist receives the response of the MS.Then, the network side assigns a VBS channel for the cell and notifies the group members tojoin the VBS call. The cells that do not respond are not assigned VBS channels.

In addition, the network side periodically detects the MSs of all the cells within the coverage

area. If no group member involved in the VBS call exists in a cell due to some reason, forexample, outgoing cell handover, the network side releases the VBS channel assigned to the

cell.

1.6.3GBFD-510323 Uplink Reply

Availability


SummaryFor a cell with group channel but no talking subscriber, the system periodically detectswhether any group subscriber is listening. If no group subscriber is listening, the assignedgroup channel is released. When any group subscriber moves into the cell, a group channels is

assigned to the group call again.

Benefits

The function reduces the congestion rate of radio channels during busy hours and enhancesthe network performance.

DescriptionAfter group channels are set up and the uplink reply function is enabled, the BSS sends an

Uplink Free message carrying a query command on the group channels in the non-speaking

MS cells according to the timer (defining the retransmission times and retransmission intervalof the downlink supervision) configured in the OMC.

If there is an MS listening on the group channel in the cell, the MS responds to the BSS withan Uplink Access message upon receiving the Uplink Free message from the BSS and


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resumes to the supervision state. The BSS returns the timer to zero upon receiving the UplinkAccess message from the MS.

If no group subscriber listens in the cell, the BSS cannot receive the Uplink Access messageduring the retransmission interval of the downlink supervision. Then the BSS retransmits the

Uplink Free message that carries a query command. If no Uplink Access message is reportedafter the Uplink Free message is retransmitted for preset times, the BSS releases the group

channel assigned to the cell and delivers a group call notification message without

descriptions of the group channel on the notification channel.

The MSs with late entry report notification responses upon receiving the group call

notification message. Then the BSS reassigns group channels in the cell and delivers a groupcall notification message with descriptions of the group channel. After receiving the

notification message, the MSs transfer themselves to the group channel for downlinklistening.

1.6.4GBFD-510305 Single Channel Group Call Originating

Availability


Summary

When a VGCS/VBS call is originated, only one TCH is occupied.

Benefits

When a VGCS/VBS call is originated, the originating cell needs only one TCH. This

improves the utilization of frequency resources, reducing the congestion rate of TCHs duringbusy hours, and enhancing the QoS of network.

Description

When a VGCS/VBS call is originated, the originating cell requires two TCHs by default,

where one TCH is a VGCS/VBS channel and the other TCH is used for the originator to talkbefore a VGCS/VBS call is established. After the VGCS/VBS call is established, the networkswitches the originator to the VGCS/VBS channel and then releases the TCH that is assigned

initially. This is called dual-channel group call originating.

In the single channel group call originating mode, the BSS switches the VGCS/VBS

originator from the SDCCH to the VGCS/VBS channel directly. In the entire VGCS/VBSoriginating phase, no more traffic channels are occupied.


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1.7 GPRS/EGPRS Service

1.7.1GBFD-114101 GPRS

Availability


Summary

The General Packet Radio Service (GPRS) is a type of end-to-end packet switched servicebased on the GSM technology.

Benefits

By providing the data service to the subscriber, the GPRS increases the operators' revenue andthe proportion of the PS services in the mobile services.

Description

Huawei GPRS is implemented by adding GPRS support nodes (GSNs) and packet control

unit (PCU) on the GSM system and upgrading the software. There are two PCU modes:

built-in PCU and external PCU. The GPRS provides quick access of PS services for the

mobile subscribers. Huawei external PCU is connected to the BSC through the Pb interface.

Huawei GPRS has an open system architecture, which facilitates smooth capacity expansion.

The standard interfaces ensure the device compatibility and supports the QoS features and thedynamic allocation of radio resources. In addition, the flexible networking and configuration

save a large amount of CAPEX for the operator in the initial phase of the GPRS serviceoperation. GPRS provides abundant packet services, for example, mobile Internet access,

e-Commerce (e-Bank and e-Currency), cluster management, remote control/remote

measurement, booking system (hotels, theatres, and airplanes), and group services (stockinformation publication).

Huawei GPRS implements mainly three functions: managing radio links and resources,controlling MS access, and providing routing functions for packet data transmission. The

radio link management includes establishment, maintenance, and release of radio links. Theradio resource management includes encoding/decoding, configuration, and multiplexing of

the radio packet channel and conversion between the CS service channels and the PS service

channels. In addition, by controlling the access of the MSs, the GPRS solves the problem of

channel contention and assigns channels for MSs according to the requested QoS. The GPRSsystem also provides routes to transmit the packet data to the SGSN and receives thedownlink data from the SGSN.

Huawei GPRS uses 16 kbit/s links on the G-Abis interface. When the CS-3 and CS-4 codingschemes are used, the rate of one PDCH is 15.6 kbit/s and 21.5 kbit/s respectively. Therefore,

when the radio channel is mapped onto the terrestrial channel, one PDCH in CS-3 and CS-4

coding schemes should be mapped onto two 16 kbit/s links. Using the dynamic additionalsub-timeslot technology, Huawei GPRS solves the transmission problem over the G-Abisinterface when the CS-3 and CS-4 coding schemes are used. The dynamic additional


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sub-timeslot technology assigns a main 16 kbit/s sub-timeslot statically and an additional 16kbit/s sub-timeslot dynamically on the G-Abis interface for each PDCH using CS-3 or CS-4.The dynamic additional sub-timeslot technology has the following features: Any idle 16 kbit/s

sub-timeslot on the G-Abis interface can be used as an additional 16 kbit/s sub-timeslot; theadditional sub-timeslot can be dynamically attached to different main timeslots within the

same site and thus the usage of additional sub-timeslot is increased based on the statisticalmultiplexing rule; the additional sub-timeslot does not need to be the neighbor of the main

timeslot; the data packet is assembled and fragmented through software, which avoids the

upgrade of hardware due to different product specifications; dynamical assignment of theTCH on the Abis interface can reduce the cost of the transmission on the Abis interface and

thus reduce the O&M cost of the equipment.

1.7.2GBFD-118901 CS-3/CS-4

AvailabilityThis feature is available from GSM-R 1.0.

Summary

The CS-3/CS-4 feature makes use of the capability that the GPRS MS already has, thus

increasing the throughput. The BSC adjusts the coding scheme to a higher level in the areawith low error bit rate according to the transmission quality of the MS.

Benefits

This feature has the following benefits:

Increases the GPRS service rate, improves the packet service performance in areas where

the EGPRS is not supported, and improves the satisfaction of the subscribers in the

entire GPRS network.

Makes full use of the capability that the GPRS MS already has, chooses more suitablecoding scheme (from CS-1 to CS-4) according to reasonable GPRS link controlalgorithm, thus improving the spectrum efficiency.

Description

According to GSM specifications, the GPRS can use four coding schemes, namely, CS-1,

CS-2, CS-3, and CS-4.

Although the CS-1 and CS-2 coding schemes ensure 100% and 90% cell coveragerespectively and meet the co-channel interference requirement C/I = 19 dB, they only have adata rate of 9.05 kbit/s and 13.4 kbit/s (containing the head of the RLC block) respectively.The reason is that the half-rate and 1/3 rate bits in the RLC blocks of the CS-1 and CS-2

schemes are used for forward error correction (FEC). This reduces the requirement for C/I

and the transmission rate.

To increase the transmission rate, Huawei provides the CS-3 and CS-4 schemes. The CS-3

and CS-4 schemes provide the transmission rate of 15.6 kbit/s and 21.4 kbit/s (containing the


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head of the RLC block) respectively. In addition, the CS-3 and CS-4 schemes have higherrequirements for C/I. During the data transmission, the BSC dynamically adjusts the channelencoding/decoding scheme according to the retransmission rate of the RLC blocks transmitted

on the uplink TBF and downlink TBF. This improves the transmission rate on the basis ofguaranteed transmission quality and maximizes the use of radio resources.

This feature supports the dynamic conversion among CS-1, CS-2,

Documents

eWSE GSM-R 5.0 BSC6000 Optional Feature Description_V1.1