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GBSS13.0Basic Feature Description

IssueV1.3

Date2011-06-20

DOCPROPERTY Confidential

HUAWEI TECHNOLOGIES CO., LTD.

Copyright Huawei Technologies Co., Ltd. 2011. 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.NoticeThe 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 this document do not constitute the warranty of any kind, express or implied.

Huawei Technologies Co., Ltd.

Address:Huawei Industrial BaseBantian, LonggangShenzhen 518129People's Republic of China

Website:http://www.huawei.com

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Contents71 Basic Features

71.1 System Improvement

71.1.1 GBFD-110000 GBSS9.0 System Improvement

81.1.2 GBFD-110001 GBSS12.0 System Improvement

91.1.3 GBFD-110030 3GPP Protocol Compliance

101.1.4 GBFD-110002 GBSS13.0 System Improvement

121.2 Radio Service Function

121.2.1 GBFD-110101 Frequency Band

131.2.2 GBFD-114401 Multi-band Sharing One BSC

141.2.3 GBFD-114901 Support for E-GSM and R-GSM Frequency Band

161.2.4 GBFD-110201 Telephone Service (TS11)

171.2.5 GBFD-110202 Emergency Call Service (TS12)

181.2.6 GBFD-110203 Point To Point Short Message Service (TS21, TS22)

191.2.7 GBFD-110204 G3 Fax (TS61, TS62)

201.2.8 GBFD-110205 Bearer Service (CSD)

221.3 Mobility Management

221.3.1 GBFD-110301 Location Updating

241.3.2 GBFD-110302 IMSI Detach

251.3.3 GBFD-110303 CS Paging

271.3.4 GBFD-110304 Authentication

281.3.5 GBFD-110601 HUAWEI I Handover

311.3.6 GBFD-110607 Directed Retry

321.3.7 GBFD-110608 SDCCH Handover

331.3.8 GBFD-110401 Basic Cell Selection

351.3.9 GBFD-110402 Basic Cell Re-selection

371.4 Connection Management

371.4.1 GBFD-110501 Call Control

381.4.2 GBFD-110502 Assignment and Immediate Assignment

401.4.3 GBFD-110503 Call Reestablishment

411.4.4 GBFD-112501 TCH Re-assignment

421.5 Radio Resource Management

421.5.1 GBFD-111001 TRX Management

431.5.2 GBFD-111002 Radio Link Management

451.5.3 GBFD-111003 Radio Common Channel Management

461.5.4 GBFD-111004 Radio Dedicated Channel Management

481.5.5 GBFD-111005 Enhanced Channel Assignment Algorithm

501.6 Operation and Maintenance

501.6.1 MRFD-210301 Configuration Management

521.6.2 MRFD-210302 Performance Management

551.6.3 MRFD-210303 Inventory Management

571.6.4 MRFD-210304 Faulty Management

611.6.5 MRFD-210305 Security Management

621.6.6 MRFD-210309 DBS Topology Maintenance

641.6.7 MRFD-210310 BTS/NodeB Software USB Download

651.6.8 GBFD-111202 O&M of BTS

671.6.9 GBFD-111203 O&M of BSC

691.6.10 GBFD-111207 BTS Test Function

711.6.11 GBFD-111210 Integrated Network Management Interface

731.6.12 GBFD-116501 Man Machine Language (MML)

741.6.13 GBFD-116402 Maintenance Mode Alarm

751.6.14 GBFD-113523 NAT Beside OM

771.7 Software Management

771.7.1 MRFD-210401 BSC/RNC Software Management

781.7.2 MRFD-210402 BTS/NodeB Software Management

801.7.3 GBFD-111213 Remote Upgrade of the BSC&BTS Software

811.7.4 MRFD-210403 License Management

831.8 GBSS Network Architecture

831.8.1 GBFD-114601 Multi-Cell Function

841.8.2 GBFD-111501 BTS Combined Cabinet

851.8.3 GBFD-111502 BTS Hybrid Cabinet Group

861.8.4 GBFD-118801 BSC Cabinet/Subrack Sharing

881.8.5 MBFD-210204 Star Topology

881.8.6 MBFD-210205 Chain Topology

891.8.7 MBFD-210206 Tree Topology

901.8.8 GBFD-118621 Connection Inter BSC over IP

911.9 System Reliability

911.9.1 GBFD-111701 Board Switchover

921.9.2 GBFD-111705 GSM Flow Control

941.9.3 GBFD-112301 Remote EAC Maintenance

951.9.4 GBFD-111214 Operation & Maintenance System One-Key Recovery

961.9.5 GBFD-111211 Reporting the Temperature List of the BTS Equipment Room

971.9.6 MRFD-210101 System Redundancy

981.9.7 MRFD-210102 Operate System Security Management

1001.9.8 MRFD-210103 Link Aggregation

1011.9.9 MRFD-210104 BSC/RNC Resource Sharing

1021.9.10 GBFD-117804 Intelligent Shutdown of TRX Due to PSU Failure

1031.9.11 GBFD-511003 Call-Based Flow Control

1041.10 Basic features

1041.10.1 GBFD-110901 Adjustment of Adaptive Timing Advance

1051.10.2 GBFD-110801 Processing of Measurement Report

1061.10.3 GBFD-110802 Pre-processing of Measurement Report

1071.10.4 GBFD-111101 System Information Sending

1091.10.5 GBFD-111102 Forced System Information Sending by OMC

1101.10.6 GBFD-111901 Supporting Three-Digit MNC

1111.10.7 GBFD-116101 Support of Daylight Saving Time

1121.10.8 GBFD-113001 SDCCH Dynamic Adjustment

1131.10.9 GBFD-112401 Cell Frequency Scan

1141.10.10 GBFD-111806 STP (Signaling Transport Point)

1151.10.11 GBFD-111802 14-Digit Signaling Point Code

1171.10.12 MRFD-210801 Interface Message Tracing

1181.10.13 MRFD-210802 User Signaling Tracing

1191.10.14 GBFD-112203 Cell Tracing

1201.10.15 GBFD-111301 LAPD Multiplexing at Abis Interface

1221.10.16 GBFD-114802 Discontinuous Reception (DRX)

1231.10.17 GBFD-111601 BTS Power Management

1241.10.18 GBFD-110703 Enhanced Power Control Algorithm

1261.10.19 GBFD-113525 DTMF Downlink Message Filter

1271.10.20 GBFD-115201 High Speed Signaling

1281.10.21 GBFD-110521 Guaranteed Emergency Call

1301.10.22 GBFD-511001 License Control for Urgency

1311.11 Interface Features

1311.11.1 GBFD-111801 Ater Interface 4:1 Multiplexing

1321.11.2 GBFD-119001 Gb Interface Function

1331.11.3 GBFD-111803 A Interface Circuit Management

1351.11.4 GBFD-111804 A Interface Protocol Process

1361.11.5 GBFD-111805 A Interface Occupation Rate Monitoring

1371.11.6 GBFD-113904 Satellite Transmission over Pb Interface

1381.12 PS Services Features

1381.12.1 GBFD-119101 Packet Channel Combination Type

1401.12.2 GBFD-119102 Packet System Information

1421.12.3 GBFD-119103 MS Types

1431.12.4 GBFD-119104 MAC Mode

1441.12.5 GBFD-119105 RLC Mode

1451.12.6 GBFD-119106 Coding Scheme

1461.12.7 GBFD-119107 Networking Control Mode

1471.12.8 GBFD-119108 Network Operation Mode Support

1491.12.9 GBFD-119109 QoS (Best Effort)

1501.12.10 GBFD-119110 Access

1511.12.11 GBFD-119111 Assignment

1531.12.12 GBFD-119112 PS Paging

1541.12.13 GBFD-119113 Timing Advance Update

1551.12.14 GBFD-119115 Power Control

1561.12.15 GBFD-119116 Uplink Flow Control

1581.12.16 GBFD-119117 Flow Control on Gb Interface

1591.13 Antenna System Solution

1591.13.1 MRFD-210601 Connection with TMA (Tower Mounted Amplifier)

1611.13.2 MRFD-210602 Remote Electrical Tilt

1641.13.3 MRFD-210604 2-Way Antenna Receive Diversity

1651.14 Synchronization Mechanism

1651.14.1 MRFD-210501 BTS/NodeB Clock

1671.14.2 MRFD-210502 BSC/RNC Clock

1681.15 Maintainability and Testing

1681.15.1 GBFD-119301 Voice Fault Diagnosis

1701.15.2 GBFD-119306 Abis Crossed Pair Diagnosis

1711.15.3 GBFD-119307 Spectrum Scan

1721.15.4 GBFD-119308 Intermodulation Testing

1731.16 Documentation

1731.16.1 MRFD-210701 Documentation

1752 Acronyms and Abbreviations

1 Basic Features1.1 System Improvement1.1.1 GBFD-110000 GBSS9.0 System ImprovementAvailabilityThis feature is introduced in GBSS9.0.SummaryThe GBSS9.0 complies with the 3GPP R6. When using new signaling processing board and interface boards, the GBSC supports up to 3072 TRXs and the GSM network can evolve to the UMTS network.BenefitsWith this feature, the BSC of large capacity is provided. Thus, the equipment footprint, the O&M cost, the power consumption, and the CAPEX and OPEX are reduced. The MBSC can be enabled with this feature. This makes it easy for the GSM network to evolve to the UMTS network.DescriptionThe GBSS9.0 complies with the 3GPP R6 and provides the following enhancements:1. The BSC supports up to 3072 TRXs.2. The newly introduced signaling processing board XPUb and interface boards POUc, GOUc, and FG2c improve the processing capability of boards.3. This feature supports the MBSC. In this way, the network can be configured as GSM only, UMTS only, or GSM&UMTS. The switching among these three configurations is easy. Thus, a smooth evolution from GSM to GSM&UMTS to UMTS is achieved.4. In MBSC mode, co-O&M, co-radio resources management, co-IP transmission, and co-hardware equipment are supported.5. GBSS9.0 supports EDGE+ Evolution, including Uplink EGPRS2-A, Downlink EGPRS2-A, MSRD, Dual Carriers in Downlink, and Latency Reduction.6. GBSS9.0 supports IP Enhancement, including A IP over E1/T1, Abis IP over E1/T1, UDP MUX for A Transmission, A over IP, and 3GPP Protocol Compliance.7. GBSS9.0 supports voice quality improvement, including AMR-WB (Adaptive Multi Rate Wide Band), Automatic Noise Compensation (ANC), and Enhancement Packet Loss Concealment (EPLC).8. GBSS9.0 supports EGPRS Service Enhancement, including Conversational QoS, PS Handover, and Early TBF Establishment.9. GBSS9.0 supports Dynamic Cell Power Off for energy saving.10. GBSS9.0 supports Intelligent Shutdown of TRX Due to PSU Failure for improving the system reliability.EnhancementNoneDependencyImpacts on the BSC hardwareThe XPUb board is introduced for signaling processing.The interface boards POUc, GOUc, and FG2c are introduced.Impacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.1.2 GBFD-110001 GBSS12.0 System ImprovementAvailabilityThis feature is introduced in GBSS12.0.SummaryThis feature provides the following enhancements and improvements in GBSS12.0: Increased system capacity Support of more network topologies Improved reliability of the network topologies Improved maintainability and testabilityBenefits The system capacity is increased in GBSS12.0, and less equipment can be used to provide the same capacity as before. Therefore, the required footprint in the equipment room and the power consumed by each TRX are reduced. GBSS12.0 supports more network topologies to meet the trend of all-IP network. The reliability of the network topologies is improved in GBSS12.0. In this way, the reliability of the GBSS system is improved in the case of sudden traffic burst. The operation and maintenance efficiency is improved in GBSS12.0.DescriptionThe System Improvement of GBSS12.0 feature is described as follows:1. The capacity of the BSC system is increased.In full configuration, the BSC supports 4,096 TRXs and a traffic volume of 24,000 Erlang.2. The BSC of GBSS12.0 supports more network topologies.The A interface supports TDM/IP dual stack and supports the gradual evolution from A over TDM to A over IP.3. The reliability of the network topologies is improved.Various flow control measures are taken to improve the reliability of the GBSS system in the case of sudden traffic burst.4. The maintainability and testability are improved.To improve the operation and maintenance efficiency, GBSS12.0 provides fault detection measures to detect the fault in speech services. In this way, a problem on the existing network can be quickly identified.EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.1.3 GBFD-110030 3GPP Protocol ComplianceAvailabilityThis feature is introduced in GBSS6.1.SummaryHuawei GBSS equipment complies with the 3GPP specifications.BenefitsIn compliance with the 3GPP R6, this feature enables the interconnection with other NEs that comply with the 3GPP R99, R4, R5, or R6. Thus, it brings diverse services with optimal performance to the subscribers and improves the competitiveness of operators.DescriptionGBSS6.1 complies with the 3GPP R99/R4.EnhancementGBSS7.0 complies with the 3GPP R99/R4.GBSS8.0 complies with the 3GPP R99/R4.GBSS8.1 complies with the 3GPP R99/R4.GBSS9.0 complies with the 3GPP R99/R4/R5/R6.GBSS12.0 complies with the 3GPP R99/R4/R5/R6.GBSS13.0 complies with the 3GPP R99/R4/R5/R6/R8.DependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsIf new features defined in the 3GPP R6 need to be provided, the MSC and MS must comply with the related specifications.1.1.4 GBFD-110002 GBSS13.0 System ImprovementAvailabilityThis feature is introduced in GBSS13.0.SummaryThis feature provides the following enhancements and improvements in GBSS13.0: New TC board DPUf and enhanced system integration Support of VAMOS Improved voice quality and support of the E-coder, EPLC, EVAD Support of identification of packet services Improved transmission efficiency and support of Abis IPHC (IP header compression) and Abis PPP multiplexing. Improved maintainability and testabilityBenefits A BSC cabinet supports 4,096 TRXs, which reduces the footprint in the equipment room and reduces the power consumption per TRX. The VAMOS solution is provided, which improves the spectral efficiency and network capacity. The voice quality is improved, which enhances the customer satisfaction. Identification of packet services improves the radio resource efficiency and increases the income of data services for operators. The Abis transmission solution enhances the transmission efficiency. The maintainability and testability improve the OM efficiency and network security. DescriptionThe System Improvement of GBSS13.0 feature is described as follows:1. The integration of the BSC system is enhanced.A new TC board DPUf is introduced. In full configuration, a BSC cabinet supports 4,096 TRXs and a traffic volume of 24,000 Erlang.2. The spectral efficiency and system capacity is increased.With the increasing number of radio voice users and the 900 MHz refarming started in cities of some countries, the GSM spectral resources may be limited. The VAMOS solution supported by GBSS13.0 improves spectral efficiency, thus relieving the limitation on system capacity.3. The voice quality is enhanced.The E-coder function is supported. The voice experience and MOS of users are improved by optimizing the voice coding and decoding algorithms of EFR, AMR users. In addition, identification of ring back tone and music is enhanced through the improved VAD technology: music identification rate > 99%; improvement of the subjective MOS of the ring back tone > 0.1.4. The identification of packet services is supported.The QoS based on the packet service identification is supported. In this way, types and characteristics of packet service applications are differentiated and the BSC allocates appropriate radio resources for each service. Radio resources can be avoided being wasted by low-rate data services and the resource usage of the whole network is improved. In addition, the user experience of data service is enhanced and the income of data services increases for operators.5. The transmission efficiency is improved.The Abis IP HC (IP header compression) and Abis PPP multiplexing are supported to improve the transmission efficiency at on the Abis interface.6. The maintainability and testability are improved.The OM and fault location functions, such as BTS antenna FDR fault detection, real-time monitoring of IP transmission status, and automatic configuration of the IP addresses, are supported to improve the OM efficiency.EnhancementNoneDependencyImpacts on the BSC hardwareA new TC board DPUf is added.Impacts on the BTS hardwareNoneDependency on other features of the GBSSNoneDependency on other NEsNone1.2 Radio Service Function1.2.1 GBFD-110101 Frequency BandAvailabilityThis feature is introduced in GBSS6.1.SummaryHuawei GBSS equipment supports the following frequency bands: GSM850, GSM900, DCS1800, and PCS1900.BenefitsWith this feature, the BTS supports multiple frequency bands and thus TRXs of different frequency bands can be inserted into the slots in the same cabinet. In this way, the number of required cabinets and the area required for the equipment room are reduced.GBSS equipment supports multiple frequency bands. Thus, the GSM network can be deployed with different frequency bands to meet the requirements of operators.DescriptionThe following table lists the frequency bands supported by Huawei GBSS equipment.

Frequency BandUplink Frequency (MS TX, BTS RX)Downlink Frequency (BTS TX, MS RX)ARFCN

850 MHz824849 MHz869894 MHz128251

900 MHz(P-GSM)890915 MHz935960 MHz1124

1800 MHz17101785 MHz18051880 MHz512885

1900 MHz18501910 MHz19301990 MHz512810

The GSM900 frequency band contains the standard P-GSM and extended E-GSM and R-GSM. The GSM900 listed in the preceding table refers to P-GSM. For details of E-GSM and R-GSM, see the optional feature GBFD-114901 "Support for E-GSM and R-GSM Frequency Band."EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.2.2 GBFD-114401 Multi-band Sharing One BSCAvailability

This feature is introduced in GBSS6.1.Summary

Multi-band sharing one BSC enables operators to deploy a multi-band network, that is, one BSC supports multiple bands. This feature enables operators to expand frequency bands, and thus alleviates the problem of insufficient frequency resources.

Benefits

Multi-band sharing one BSC enables a network to support multiple frequency bands and enables operators to expand frequency bands.

Description

Huawei GBSS supports GSM900, DCS1800, PCS1900, and GSM850. Huawei GBSS supports multi-band network sharing one BSC. DCS1800 and PCS1900, when these two frequency bands build a multi-band network, some restriction list below:DCS1800 cell and PCS1900 cell cannot be configured as neighboring cell One cells neighboring cell cannot has DCS1800 cell and PCS1900 cell at the same timeHuawei GBSS supports the following types of multi-band networks:

GSM850+GSM900+DCS1800

GSM850+GSM900+PCS1900In a multi-band network, the parameters associated with the cell selection and handover can be set according to the specific frequency band so that the strategies of cell selection, cell reselection, and handover between different bands can be implemented. The dual-band network is the most common multi-band network. The dual-band network consists of two types: GSM900+DCS1800 and GSM850+PCS1900. Enhancement

NoneDependency

Impacts on the BSC hardwareNoneImpacts on the BTS hardwareRefer to the BTS dependency in the GBSS13.0 Feature List.

Dependency on other GBSS featuresNoneDependency on other NEsNone1.2.3 GBFD-114901 Support for E-GSM and R-GSM Frequency BandAvailability

This feature is introduced in GBSS6.1.

Summary

Huawei GBSS equipment supports the E-GSM900 and R-GSM900 frequency bands.

Benefits

This feature provides the following benefits:This feature enables services to be processed on the extended frequency bands and extends the frequency range.

The state radio regulatory commission of each country is responsible for the division and selling of the frequency resources of the country. The GSM900 is the commonly used frequency band. To fully utilize frequency resources, the P-GSM900 frequency band is extended to bring more benefits to governments and operators.

In this way, the related government organizations can make profits by selling this frequency band.

In addition, the operators obtain more radio resources and thus make more profits by providing better services to end users.

Description

The operating frequency of E-GSM (including the standard GSM900) is as follows:

Uplink: 880915 MHz

Downlink: 925960 MHz

ARFCN: 0124, 9751023

The operating frequency of R-GSM (dedicated to the railway communications) is as follows:Uplink: 876915 MHz

Downlink: 921960 MHz

ARFCN: 0124, 9551023The E-GSM900, R-GSM900, and P-GSM900 belong to the same frequency band while their frequencies are not adjacent. Therefore, the extended frequency bands of E-GSM and R-GSM are introduced. The E-GSM extended frequency band refers to the E-GSM frequency band excluding the P-GSM frequency band. The R-GSM extended frequency band refers to the R-GSM frequency band excluding the E-GSM frequency band.

For the cells configured with E-GSM extended frequency band or R-GSM frequency band, the system adopts different channel assignment strategies according to the frequency band supporting capability of the MS and the channel. During the immediate assignment, the system assigns a channel to the MS based on the frequency band supported by the BCCH carrier. When assigning a channel, the system obtains the classmark of the MS and then determines whether a channel is supported by the MS. Among all the channels supported by the MS, the system preferentially assigns a channel that is not in the intersection of the frequency bands to the MS. For example, if an MS supports the E-GSM band, and the available channels are carried on the P-GSM band and the E-GSM extended band, the system preferentially assigns the channel on the E-GSM extended band to the MS. The band intersection, that is, P-GSM band, is reserved for other MSs with weak multiband capability.

Enhancement

None

Dependency

Impacts on the BSC hardwareNone

Impacts on the BTS hardwareRefer to the BTS dependency in the GBSS13.0 Feature List.

Dependency on other GBSS featuresNone

Dependency on other NEsE-GSM and R-GSM should be support by MS.1.2.4 GBFD-110201 Telephone Service (TS11)AvailabilityThis feature is introduced in GBSS6.1.SummaryHuawei GBSS supports the telephone service (TS11) specified in GSM specifications.The telephone service can be classified into mobile-originated calls (MOC) and mobile-terminated calls (MTC). The full rate (FR) speech coding is adopted by default. The speech calls can be made not only between MSs within a GSM PLMN, but also between a PLMN MS and a subscriber of PSTN or other communication networks.BenefitsTelephone service is a basic speech service specified in GSM specifications. It is also one of the basic speech service functions provided by the operators. The excellent speech service provided by Huawei BSS provides the following benefits: Telephone services with high quality, hence better user experience for subscribers Better brand reputation, hence increase in the operators' profitDescriptionTelephone service (TS11) specified in GSM specifications is a basic function of the GSM equipment. It is also a basic service provided by Huawei GBSS.In terms of the called party, the telephone service is classified into MOCs and MTCs. The telephone service supports the speech calls between MSs within a GSM PLMN, also between a PLMN MS and a subscriber of PSTN or other communication networks. In the BSS, the transcoder & rate adaptation unit (TRAU) is responsible for the speech conversion between the GSM speech codings and the 64 kbit/s PCM coding. If the speech coding schemes specified in optional features are not activated for a common call, the full rate speech coding is adopted by default.EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.2.5 GBFD-110202 Emergency Call Service (TS12)AvailabilityThis feature is introduced in GBSS6.1.SummaryHuawei GBSS supports the emergency call service (TS12) specified in GSM specifications and provides higher priority for the emergency call service.BenefitsEmergency call service enables a subscriber to contact local services for assistance in case of emergency. For subscribers in emergencies, the emergency call service is of great importance. During an emergency, the subscriber can dial the specified emergency service number free of charge for assistance even if the MS is suspended or the subscriber is a defaulting subscriber. The emergency call service takes precedence over other services in accessing the network. Even located in congested cells, the subscriber can contact the aid agencies by dialing the emergency service number.DescriptionEmergency call service (TS12) specified in GSM specifications is a basic function of the GSM equipment. It is also a basic service provided by Huawei GBSS.The emergency call takes precedence over common calls. Compared with common calls, the procedure of the emergency call is simplified to accelerate the call establishment and to ensure a higher call establishment success rate. For example, during the immediate assignment procedure, a traffic channel (TCH) can be assigned directly so that an emergency call can be quickly and easily allocated with radio resources.EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.2.6 GBFD-110203 Point To Point Short Message Service (TS21, TS22)AvailabilityThis feature is introduced in GBSS6.1.SummaryHuawei GBSS supports the TS21 and TS22 services specified in GSM specifications, that is, the sending and receiving of short messages.BenefitsThe point-to-point short message service is more and more widely used in daily life and work. As a value-added service, the short message service is a complement to the non-diversified mobile speech services of the GSM. The MS can exchange information with other MSs by using the point-to-point short message services. This feature provides the following benefits: The point-to-point short message service meets the subscribers' increasingly diversified data service requirements. The point-to-point short message service has become an increasingly important source of operators' revenue and makes the operators' profit more diversified. The point-to-point short message service can be provided as the SP service to enrich the operating of the operators.DescriptionMobile-terminated (MT) point-to-point short message service (TS11) and mobile-originated (MO) point-to-point short message service (TS12) specified in GSM specifications are basic functions of the GSM equipment. They are also basic services provided by Huawei GBSS.The point-to-point short message service can be used to exchange information in plain text. With this service, the subscribers can exchange simple information with each other and the operators can send service promotion information and sale information. Both the short message center (SMC) and the MS can initiate the point-to-point short message service. The BSS supports the sending and receiving of the short messages. On receiving the signaling of a short message from the MSC, the BSS forwards the short message to the MS. In turn, on receiving a short message from the MS, the BSS forwards the short message to the MSC.The short message here refers to the one that is transmitted through SS7 signaling. The short message service implemented in the PS domain is not included. The PS short message is a function mainly implemented by the SGSN. The PS short message is treated as a common data service on the BSC side.EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsThe SMS center is needed.1.2.7 GBFD-110204 G3 Fax (TS61, TS62)AvailabilityThis feature is introduced in GBSS6.1.SummaryHuawei GBSS supports the TS61 and TS62 services specified in GSM specifications. TS61 refers to the G3 alternate voice and fax service and TS62 refers to the G3 automatic voice and fax service. The TS61 and TS62 enable the MS to send and receive the fax.BenefitsThe G3 fax feature is a value-added mobile data service that allows MSs to send and receive the voice fax. The G3 fax feature complements the non-diversified mobile speech service of the GSM and enables MSs to carry out fax services. This feature provides the following benefits: This feature enables the MS to receive and send fax any time anywhere and meets the diversified requirements of the subscribers. This feature enabled operators to provide mobile fax service to extend the service range and the source of revenue.DescriptionTS61 fax and TS62 fax services specified in GSM specifications are basic functions of the GSM equipment. They are also basic services provided by Huawei GBSS.With the TS61 fax and TS62 fax services, the MS can send and receive the voice fax.The fax service is realized through other upper-layer protocols. Therefore, the BSS provides the lower-layer connection but does not process the upper-layer services.The main device required by this feature is deployed in the CN.This feature cannot be used in A IP scenario. EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.2.8 GBFD-110205 Bearer Service (CSD)AvailabilityThis feature is introduced in GBSS6.1.SummaryHuawei BSS supports the traditional CSD services and the data services of multiple rates.BenefitsBoth CSD and GPRS are the standard 2G data services.Data services are more and more widely used in daily life and work. As a value-added mobile data service, CSD complements the non-diversified GSM mobile speech services to some extent. With the CSD service, the MS can connect to the operators' data network or even to the Internet.This feature provides the follows benefits: The CSD service meets the subscribers' increasingly diversified data service requirements. The CSD service also enables data transfer between networks. The CSD service has become an increasingly important source of operators' revenue and increases the operators' profit. Operators can provide diversified services on the data platform of CSD to attract more subscribers, thereby achieving more profit. Unlike GPRS, CSD does not require the change of the existing BSS hardware. Instead, CSD can be implemented directly in the existing system without adding the PCU device or hardware and software. This reduces the space required by the equipment room and facilitates the management of the equipment room. Moreover, the CSD increases the choices of data services.DescriptionHuawei GBSS supports various bearer services specified in GSM specifications. The GBSS provides the lower-layer connection but does not process the upper-layer services. The bearer service can be used in low-rate data service applications. Huawei GBSS supports the following bearer services: BS21 asynchronous duplex circuit data service, transparent/nontransparent, 300 bps BS22 asynchronous duplex circuit data service, transparent/nontransparent, 1200 bps BS23 asynchronous duplex circuit data service, transparent/nontransparent, 1200/75 bps (Remark 1) BS24 asynchronous duplex circuit data service, transparent/nontransparent, 2400 bps BS25 asynchronous duplex circuit data service, transparent/nontransparent, 4800 bps BS26 asynchronous duplex circuit data service, transparent/nontransparent, 9600 bps BS31 synchronous duplex circuit data service, transparent/nontransparent, 1200 bps BS32 synchronous duplex circuit data service, transparent/nontransparent, 2400 bps BS33 synchronous duplex circuit data service, transparent/nontransparent, 4800 bps BS34 synchronous duplex circuit data service, transparent/nontransparent, 9600 bps BS41 PAD access service, asynchronous circuit, transparent/nontransparent, 300 bps BS42 PAD access service, asynchronous circuit, transparent/nontransparent, 1200 bps BS43 PAD access service, asynchronous circuit, transparent/nontransparent, 1200/75 bps (Remark 1) BS44 PAD access service, asynchronous circuit, transparent/nontransparent, 2400 bps BS45 PAD access service, asynchronous circuit, transparent/nontransparent, 4800 bps BS46 PAD access service, asynchronous circuit, transparent/nontransparent, 9600 bps BS51 packet access service, 2.4 kbps, synchronous, UDI, nontransparent BS52 packet access service, 4.8 kbps, synchronous, UDI, nontransparent BS53 packet access service, 9.6 kbps, synchronous, UDI, nontransparent BS61 alternate speech/data service, transparent/nontransparent BS81 speech followed by data serviceRemark 1: Bearer services BS23 and BS43 are applicable to the MOC only. In BS23 and BS43 services, the data rate of 75 bit/s is applicable to the uplink and the data rate of 1200 bit/s is applicable to the downlink.EnhancementGBSS8.0The service of 14.4 kbit/s is realized as an optional feature of GBSS8.0, that is, 119405 14.4Kbps Circuit Switched Data.DependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.3 Mobility Management1.3.1 GBFD-110301 Location UpdatingAvailabilityThis feature is introduced in GBSS6.1.SummaryTo ensure that services such as paging service can be processed normally, the network needs to know the location of the MS. The MS registers to the network through the location updating procedure. In this way, the VLR and HLR keep track of the location information about the MS, thus ensuring the normal communication of MSs.BenefitsLocation updating is a basic feature for operators to provide the CS speech services.Description The location updating procedure is the signaling procedure for the MS to update the location information on the network. This ensures that the location information about the MS stored in the HLR and VLR is consistent with the actual location information about the MS.The general location updating procedure is as follows: 1. The MS initiates the access request with the location updating as the access cause; 2. The network side allocates a signaling channel to the MS;3. The MS sends a location updating request on this signaling channel; 4. The NSS side determines whether to accept the location updating request based on the identity of the MS.In different scenarios, three types of specific location updating procedures are initiated: normal location updating, periodic location updating, and IMSI attach location updating. Normal location updatingWhen the location of an MS changes, the MS initiates a normal location updating procedure. During the normal location updating procedure, the network side may initiate other supplementary procedures, such as the classmark interrogation, identification request, authentication, and ciphering mode setting. Periodic location updatingWhen timer T3212 expires, the MS initiates the periodic updating procedure. The value of T3212 is provided by the network in the system information type 3 message. The MS resolves this system information message to obtain the value of the T3212 timer. IMIS attach location updating procedureThe IMSI attach location updating is a complement to the IMSI detach procedure. The network uses the system information type 3 message to indicate whether the IMSI attach and IMSI detach are allowed. If the network indicates that the IMSI attach and IMSI detach are required, the MS triggers the IMSI attach procedure when the IMSI is activated. When the MS activates the IMSI or the MS has moved from a non-coverage area to a coverage area, the IMSI attach procedure is triggered if the IMSI attach is allowed and the stored location area of the MS is the same as the location area of the serving cell.Location updating ensures smooth communication by updating the information about the location of MSs stored in the VLR and HLR in real time.EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.3.2 GBFD-110302 IMSI DetachAvailabilityThis feature is introduced in GBSS6.1.SummaryAfter the IMSI is detached, the subscriber is marked as an invalid subscriber by the network. Then, the network does not send any paging message to this subscriber. BenefitsIMSI detach is a basic feature for the operators to provide the CS speech services.DescriptionIMSI attach and detach are IMSI-specific procedures. When an MS is powered off, it sends the network the last message containing the detach request. On receiving this message, the MSC/VLR sets the subscriber status to invalid. Then, the network does not page this subscriber.During the IMSI detach, the subscriber status is set only on the MSC/VLR but not on the HLR. After the MS powers on again, the MS performs the IMSI attach procedure if the current location area of the MS is the same as the location area registered before the MS is powered off. Otherwise, the MS performs the normal location updating procedure to make the location information stored in the HLR and VLR the same as the actual location area of the MS.The network informs the MS whether the IMSI attach or detach is allowed by sending the system information type 3 message.EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.3.3 GBFD-110303 CS PagingAvailabilityThis feature is introduced in GBSS6.1.SummaryThe network instructs the MS as the called party to access the network through the paging procedure to complete the call establishment.BenefitsPaging is a basic feature for the operators to provide the CS speech services. The paging algorithm determines the paging efficiency of the GBSS. The paging algorithm provides the following benefits: The paging processing capability is one of the KPIs that indicate the system capability. Huawei GBSS paging algorithm guarantees the paging processing capability while maintaining the paging efficiency and reducing the paging load. The paging algorithm prevents the paging from being missed so that the subscriber can receive calls. Thus, complaints decrease and customer satisfaction increases.DescriptionPaging procedure: To answer the call timely, the MS in idle state listens to the paging channel all the time. If there is a paging message to the MS, the MS responds to the paging and completes the subsequent procedure as a called party.The pagings are classified into PS pagings and CS pagings. When there is downlink data to be transferred to the MS, the SGSN initiates the PS paging procedure. If a packet common control channel (PCCCH) is configured, the PS paging message is transmitted on the PCCCH. If PCCCH is not configured, the PS message is transmitted on PCH.The CS paging message is sent on PCH. When a call arrives at the MSC that serves the MS, the MSC determines the location area of the MS and then sends the paging message to all BSCs in this location area. The BSCs determine the paging cell based on the location area and determine the paging group that the MS belongs to based on the IMSI. Then, the BSC sends the paging message to the corresponding BTS. The BTS then sends the paging message to the MS on the assigned PCH.Huawei GBSS supports the following three standard paging modes: Common paging modeThe paging message is transmitted on only the configured PCH and the IMSI defined channel. Complete paging modeWhen an MS group is informed in this mode, the paging message of this group may be transmitted on any PCH of the same timeslot. When dynamic change of PCH configuration occurs, paging message loss can be avoided in this mode. Spaced paging modeThe BSS adds the paging message of a group to another paging channel to avoid temporary overload. That is, the MS receiving common paging messages on channel N can get the paging message on the next paging channel N+2.Huawei GBSS supports paging message queuing, paging retransmission, simultaneous processing of multiple pages, and paging flow control. This can effectively improve and ensure the paging capacity of the BSC. Paging message queuingThe transmission of paging messages on the Um interface is limited on the basis of paging groups. The paging message of one paging group can only be transmitted on the paging block corresponding to the paging group. Therefore, the paging message queuing is implemented on the BTS. That is, during the period when the BTS waits for transmission, the paging messages from the BSC are buffered on the BTS. Upon the transmission, the BTS selects the appropriate paging messages from the queue to transmit on the corresponding block. If many paging messages have the same transmission priority, the BTS processes these messages according to the FIFO principle. Paging retransmissionGenerally, both the CN and BSS of the GSM network allow paging retransmission. A two-level retransmission mechanism is provided. One retransmission is initiated by the CN to handle long intermittence during the paging transmission. The retransmission initiated by the CN takes a relatively long time. The other retransmission is implemented on the BTS. The retransmission initiated by the BTS takes a relatively short time. Hence, the two-level retransmission mechanism reduces the signaling load on the Abis interface and A interface. Huawei BSS supports the paging retransmission. That is, when there is no paging message or immediate assignment message to be transmitted on the corresponding sending block, the paging messages that are already transmitted are retransmitted on this sending block. The maximum number of paging retransmissions can be specified by the system parameter. Simultaneous processing of multiple paging messagesEach paging command from the BSC comprises only one paging message sent to one MS, but each paging request on the Um interface may pack a maximum of four paging messages sent to four different MSs. Therefore, to improve the efficiency of the paging processing, the number of paging commands to the MS included in the paging message on the Um interface should be as many as that is specified. In detail, a maximum of four paging messages can be included. When the sending block of a paging group is polled, the BTS searches for the paging messages to be transmitted in the paging queue corresponding to the paging group. Then, based on the maximum combination principle, the BTS packs these paging messages or several of the paging messages as appropriate type of paging request on the Um interface. The paging request is then sent on the sending block to the MSs. In this way, the paging commands of multiple MSs can be transmitted on the Um interface. Paging flow controlWhen the paging flow from the MSC exceeds the processing capability of the BSS, the BSS initiates the selective flow control based on the current network situation to ensure the robustness and proper operation of the system, the high efficiency of the paging capacity, and the smoothness and stability of services.EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.3.4 GBFD-110304 AuthenticationAvailabilityThis feature is introduced in GBSS6.1.SummaryAuthentication is an identity verification procedure. With the authentication, only legal subscribers can access the network.BenefitsAuthentication is a basic feature for the operators to provide the CS speech services. This feature ensures that only the legal subscribers can access the network, thereby guaranteeing the security of the network and services.DescriptionAuthentication is a procedure in which the GSM network verifies the validity of the identity of an MS.The purpose of authentication is to prevent unauthorized subscribers from accessing the network and to protect the private information of authorized subscribers.The network initiates the authentication procedure in the following situations: The MS requests to change the information restored in VLR or HLR. Service access such as MOC, MTC, MS activation or deactivation, or supplementary services is required. Initial network access is required after MSC/VLR reboot. The ciphering key Kc sequence is mismatched. The network needs to determine whether the MS is accessible to network. Parameters for the MS to calculate new ciphering key is required.The authentication procedure is always initiated and controlled by the network.After the RR connection between the MSC and the BSS is established, the network can decide whether to initiate the authentication procedure to verify the subscriber's identity. The BSS is mainly responsible for the RR connection establishment and the transparent transmission between the MSC and the MS. When the network determines to initiate the authentication procedure, the MSC/VLR sends the MS an Authentication Request message to trigger the authentication procedure. The MS responds to this request with an Authentication Response message and reports the calculated result to the CN for approval for the authentication.Authentication strengthens the network identification of subscribers and ensures their security.EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.3.5 GBFD-110601 HUAWEI I HandoverAvailabilityThis feature is introduced in GBSS6.1.SummaryThis feature involves the following phases: MR reporting, MR processing, handover decision, and handover execution. In the handover decision phase, an appropriate candidate cell is selected for the handover.BenefitsWith this feature, the MSs in movement can continue with the ongoing call.Handover is an important method to ensure the voice quality.Handover optimizes the overall performance of the system by adjusting the traffic volume of the cells.DescriptionThe GSM service area is composed of a number of cells that provide continuous coverage. The handover technique is introduced into the GSM system to enable the MSs in movement to continue with the ongoing calls within the coverage area, thus optimizing the network performance.This feature involves the following phases: MR reporting, MR processing, handover decision, and handover execution. The NEs involved in the handover include the MS, BSS, and MSC. The measurement and MR reporting are implemented by the MS and BTS. The MS measures the downlink level strength, downlink quality, and TA of the GSM cell and then reports the information to the BTS. The BTS measures the receive level strength and quality of the MS and then reports all the information to the BSC. Generally, the MR processing is implemented by the BSC. The BSC performs the basic functions such as filtering and interpolation to provide reference for the subsequent handover decisions. If the BTS performs the pre-processing of MRs, the MR processing can be implemented by the BTS. Based on different factors such as radio signal quality, radio signal level, speed, load, and requirement of operators, the handover decision algorithm determines which candidate cell to be used as the target cell for handover. After the target cell is selected, the handover procedure is initiated. If the handover failure or rollback occurs, the MR indicating the result is reported to the handover decision module. Then, the handover decision algorithm selects another candidate cell as the target cell.The handover decision algorithm is categorized into five types: high-speed railway fast handover, emergency handover, enhanced dual-band network handover, load handover, and normal handover. The emergency handover is of five types: TA handover, bad quality handover, quick level drop handover, interference handover, and no downlink measurement report handover. The normal handover is of the following types: edge handover, hierarchical handover, PBGT handover, concentric cell handover, AMR handover, and better 3G cell handover.High-speed railway fast handover: This handover reduces the filtering time, speeds up the handover and determines whether to trigger the handover based on the frequency offset and signal level. In addition, the neighboring cell on a chain is selected to improve the reliability.TA handover: The timing advance can be used as a standard to limit the cell coverage to some extent. The BSC determines whether the TA value of the current MS exceeds the timing advance limit (TALIM). If the TALIM is exceeded, the BSC initiates an emergency handover with the cause value being great TA value. The TA value ranges from 0 to 63. The step of each bit corresponds to the distance from the MS to the BTS, which is 553.5 m. The TA value 63 corresponds to a distance of 35 km. If the serving cell meets the conditions to trigger a TA emergency handover, penalty is performed on the originating cell after a successful to prevent a handover back to this cell due to other causes. The TA handover algorithm has been optimized to meet the special requirements of the extended cells.Quick level drop handover: This handover is responsive to the signals with rapid signal level drop. The average value filtering and P/N decision methods are used in edge handover and PBGT handover, and therefore the time for measurement and decision is prolonged. Thus, these handovers are not sensitive to rapid level drop in a short period. Therefore, concerning the rapid level drop, you can perform finite impact response (FIR) filtering on the original receive level. This filtering method is responsive to the rapid level drop based on the drop slope of the original receive level. When the quick level drop handover is triggered, the selected target cell should have the highest priority based on the ranking in the preprocessing. If the candidate GSM cells do not meet the handover conditions and there are neighboring 3G cells available, the inter-RAT handover is performed if allowed. Otherwise, the algorithm determines to perform the emergency handover of other types.Edge handover: Edge handover is a type of rescue handover based on the signal level. To trigger an edge handover, the receive level of the target cell should be at least one hysteresis value (hysteresis of inter-cell handover) higher than the receive level of the serving cell. When the receive level of the serving cell is lower than the edge handover threshold and the P/N criterion is met within a period of measurement time, the edge handover is triggered for the MS to maintain proper communication quality.Bad quality handover: The transmission quality of the link is measured in bit error ratio (BER). The BSC determines the quality of a radio link based on the quality level in the MR. There are eight quality levels ranging from 0 to 7. Level 0 is the best and level 7 is the worst. Bad quality level may be resulted from low signal power or channel interference. When the receive quality of the serving cell is lower than the BQ handover threshold, the BSC starts the handover algorithm for the MS to maintain proper communication quality. This procedure is called BQ handover. If the serving cell meets the conditions to trigger the bad quality handover, penalty is performed on the originating cell after a successful handover to prevent a handover back to the cell due to other causes.Interference handover: When the receive level of the serving cell is good, the network starts the interference handover for the MS to maintain proper communication quality if the receive quality deteriorates to a certain degree. If interference handover is triggered, the quality of the channel in the serving cell is affected to some extent. Conversation, however, can be maintained. At the same time, the receive level of the serving cell is relatively high and other channel in the serving cell may be affected to some extent. Therefore, the intra-cell handover is recommended.PBGT handover: PBGT handover is also referred to as better cell handover. The PBGT handover is based on the path loss. In PBGT handover, the system searches in real-time for a cell with less path loss and in compliance with the system requirements. Then, the BSC determines whether a handover is required. Compared with other handover algorithms, the PBGT handover is triggered on the basis of path loss instead of receive level.Hierarchical handover: The radio systems with the same coverage can be divided into four layers. The highest layer, also the fourth layer, is the umbrella-shaped GSM900 cell with wide coverage. This GSM900 cell implements the coverage and the connection of the fast-moving MS. The third layer is composed of GSM900 macro cells. These are the most widely used cells of the current system. Most of the MSs camp on this layer. The second layer is composed of DCS1800 micro cells with smaller coverage. The DCS1800 cell is also the target cell for capacity expansion aiming at solving the problem of insufficient frequency resources. The bottom layer is composed of DCS1800 pico cells, which aims to meet the requirements of the hot spot or the blind spot. The cell at the lower layer has a higher priority than the cell at the higher layer.Inter-layer handover: This handover is performed between different layers or between different hierarchies at the same layer. The inter-layer handover is not performed between cells at the same layer and the same hierarchy. If the following situations occur in a layered and hierarchical network: A cell with a higher priority exists. The cell meets the conditions to trigger the hierarchical handover. That is, the signal level of a neighboring cell is higher than the sum of inter-layer handover threshold and hysteresis. The P/N criterion is met. That is, within period P, the conditions to trigger the handover are met for period N.Then, the call is handed over to the cell with a higher priority even if the serving cell can provide good services. The purpose of hierarchical handover is to direct the traffic of the MS to the cell with a higher priority so that the traffic can be distributed more properly.During the call, the hierarchical handover flexibly adjusts the traffic distribution between different layers to meet the requirements of various networking modes.EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.3.6 GBFD-110607 Directed RetryAvailabilityThis feature is introduced in GBSS6.1.SummaryDirected retry is a special type of handover. That is, during the assignment procedure, the BSC initiates the directed retry procedure to switch the MS to a neighboring cell if no TCH is available or the traffic load is heavy in the serving cell.BenefitsThis feature provides the following benefits: This feature helps reduce the call access failure due to TCH congestion in the serving cell, and hence increases the access success rate. This feature can balance the traffic load between different cells, and hence avoids the traffic load imbalance among cells.DescriptionWhen the MS initiates a call, the BSC determines the assignment procedure that is to be used according to the load of the current cell if the BSC receives an ASSIGN REQ message from the MSC. There are three types of assignment procedures: normal assignment procedure, mode modification procedure, and directed retry procedure. If the load of the cell is so high that the cell does not admit a new service or that a newly admitted service will affect the existing services, the BSC determines to perform a directed retry. The directed retry procedure is as follows:The BSC sends a CHAN ACTIV message to the target cell. After receiving a CHAN ACTIV ACK message, the BSC requests circuit service resources. After the requested resources are allocated successfully, the BSC sends an HO CMD to the MS through the originating cell. The MS sends an HO ACC message in the target cell to attempt to access the network. The BTS sends an HO DETECT message to notify the BSC of the request and sends the PHY INFO message to the MS. The MS accesses the network through the FIRST SABM frame. Then, the BTS sends an EST IND message and a UA frame to the MS for acknowledgment. The MS sends an HO CMP message to the BSC through the target cell. Then, the BSC sends an ASS CMP message to the MSC to process signaling in other assignment procedures. The mobile originated procedure is complete.Based on the homing BSC and MSC of the serving cell and target cell, the directed retry can be classified into these types: intra-BSC directed retry, inter-BSC directed retry, and inter-MSC directed retry. The directed retry helps reduce the call access failures due to TCH congestion in the serving cell, increase the access success rate, and improve the network quality.EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.3.7 GBFD-110608 SDCCH HandoverAvailabilityThis feature is introduced in GBSS6.1.SummarySDCCH handover refers to the handover from one SDCCH to another SDCCH in the immediate assignment procedure.BenefitsThis feature helps improve the access success rate of MSs on the edge of the network.DescriptionThe SDCCH handover refers to the handover from one SDCCH to another SDCCH. This feature helps improve the access success rate of MSs on the edge of the network, thus improving the network quality.The handover decision in SDCCH status is the same as that in TCH status. That is, the TA handover, interference handover, BQ handover, signal level rapid fall handover, and edge handover are allowed, and the load handover, PBGT handover, concentric handover, and AMR handover are not allowed. In addition, the parameter used for handover decision in SDCCH status is the same as that used for handover decision in TCH status.Generally, the time for seizing the SDCCH is short, and thus the SDCCH handover seldom occurs. To prevent unnecessary handovers due to inaccurate MR in the initial phase of call setup, the minimum time to start the SDCCH handover can be configured to control the handover rate of the signaling channel.EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.3.8 GBFD-110401 Basic Cell SelectionAvailabilityThis feature is introduced in GBSS6.1.SummaryWhen the MS is powered on or moves from a blind spot to a coverage area, the MS searches for all frequencies that the PLMN allows and selects a proper cell to camp on. This procedure is called cell selection.BenefitsThis feature facilitates the automatic selection of the network on the MS and avoids the complexity of manual operations.DescriptionThe cell selection involves two scenarios: The MS does not store any information about the BCCH TRX.The MS sets a search frequency band first. When the MS is tuned to the frequency with the highest level, it decides whether this frequency is the BCCH TRX. If it is the BCCH TRX, the MS tries to decode the SCH to synchronize with this frequency and read the BCCH system broadcast messages. The MS camps on this cell if the MS can decode the BCCH data correctly and confirms that this cell belongs to the selected PLMN, parameter C1 exceeds 0, and that the access to this cell is not denied. Otherwise, the MS is tuned to the frequency with the second highest level and repeats the decoding and data verification procedures until the MS finds the available cell. The MS stores the information about the BCCH frequency.The MS searches for the stored BCCH frequency first. If the MS can decode the BCCH data of the cell but cannot camp on this cell, it checks the BA (BCCH) list. If none of the BCCH frequency in the list is suitable, the MS initiates the cell selection procedure without the BCCH message mentioned earlier.Whether an MS can select a cell to camp on is also influenced by the following factors: Two parameters in system information 1Cell bar access (CBA): It indicates whether a cell allows access of an MS. Cell bar access is a one-bit code: Value 0 indicates that the access is allowed, and value 1 indicates that the access is not allowed. This parameter does not influence the access of MSs that are handed over to the cell.Access control (AC): It can be graded from level 0 to level 9 and from level 11 to level 15. Usually each GSM subscriber has an access level and each level is represented by one bit: Value 1 indicates that the current cell does not allow the access of the MS with the corresponding level value. Otherwise, the access is allowed. Subscribers with level 11 to level 15 have higher priority over subscribers with level 0 to level 9 in access, but there is no priority difference within level 11 to level 15 or within level 0 to level 9. The minimum receive level allowed in system information 3:RXLEV_ACCESS_MIN: It is the signal level threshold represented by a 6-bit code. The range 0 to 63 corresponds to the level value range 110 dBm to 47 dBm. Access parameter CBQ in system information 4Cell Bar Qualify (CBQ): It is a one-bit code. CBQ and CBA together indicate the priority status of the cell. For details, see the following table.

CBQCBAPriority Status of Cell SelectionCell Reselection Status

00NormalNormal

01BarredBarred

10LowNormal

11LowNormal

EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.3.9 GBFD-110402 Basic Cell Re-selectionAvailabilityThis feature is introduced in GBSS6.1.SummaryThe MS in idle mode reselects the cell based on the trigger condition to find a cell that can provide better services. This procedure is called cell reselection.BenefitsThe MS is always bound to a relatively good cell to obtain better service quality.DescriptionThe MS in idle mode periodically measures the receive level of the downlink BCCH TRX of the serving cell and that of all downlink BCCH TRX in the BA list indicated by the BCCH system information. Based on the corresponding algorithm, the MS then calculates the C2 value and determines whether to select a new serving cell. The MS periodically reselect cells based on the cell reselection algorithm. In this way, the MS can find a cell that can provide better service. This feature enables the MS to bind to a relatively good cell to obtain better service quality.The cell reselection of the MS is based on the BA list provided in the system broadcast information about the serving cell. The GSM network has two BA lists. One is transmitted in the system information on the BCCH, used for cell selection and reselection of MSs in idle mode. The other is transmitted in the system information on the SACCH, used to inform the MS about which BCCH TRX is used for handover monitoring in dedicated mode.The MS triggers the cell reselection procedure in any one of the following scenarios (if the C2 algorithm is not activated, that is, C2 = C1): The C2 value of a cell (belonging to the same location area as the current cell) exceeds the C2 value of the current cell for five consecutive seconds. The C1 value of a cell (belonging to a location area different from that of the current cell) exceeds the sum of the C2 value of the current serving cell and cell selection hysteresis value for five consecutive seconds. The current serving cell is barred. The MS detects a downlink failure. The C1 value of the serving cell is less than 0 for five consecutive seconds. The access attempt fails after the number of retransmissions exceeds the maximum one during the random access of the MS.The following parameter in system information 4 determines whether to activate the C2 calculation:PI (Cell Reselect Parameters Indication) indicates whether the MS uses C2 as cell reselection parameter and whether the parameters related to the C2 formula exist. It is a one-bit code: 0 indicates that the MS uses C1 as the cell reselection parameter; 1 indicates that the MS uses C2 retrieved from the system information as the cell reselection parameter.EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.4 Connection Management1.4.1 GBFD-110501 Call ControlAvailabilityThis feature is introduced in GBSS6.1.SummaryThrough the call control procedure, the BSS provides required radio resources and terrestrial circuit to the call so that the CN can complete the call connection procedure.BenefitsCall control is a basic feature for the operators to provide the CS speech services.DescriptionHuawei GBSS supports MOC, MTC, and emergency call. Through resource management algorithms and control functions, the BSC provides the transmission channel for the call control signaling between the MS and the MSC by establishing the RR connection. In the call control, the BSS handles the call requests by priorities. For example, the emergency call takes precedence over common calls, and thus the BSS preferentially allocate the required resources to the emergency call. For the BSC, the call control mainly involves the radio channel allocation, A interface resource allocation with the coordination of MSC, and TCH release. The following call procedures are supported: MOC MTC Emergency call MS-originated call release Network-originated call releaseEnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.4.2 GBFD-110502 Assignment and Immediate AssignmentAvailabilityThis feature is introduced in GBSS6.1.SummaryImmediate assignment and assignment are two important procedures during the call setup. Through the immediate assignment procedure, the MS can establish an RR connection with the network. Through the assignment procedure, the network assigns TCHs to the MS. In this way, a stable service connection is established between the network and the MS.BenefitsImmediate assignment and assignment are basic features for the operators to provide the CS speech services. Excellent immediate assignment and assignment algorithms ensure relatively high KPIs, and thus improves the radio network performance.DescriptionHuawei GBSS supports the immediate assignment procedure, immediate assignment combination, and corresponding assignment procedure specified in GSM specifications.The purpose of the immediate assignment is to establish the RR connection between the MS and the network.Through the assignment procedure, the BSS assigns the TCH to the MS. The assignment is classified into early assignment for MOC, late assignment for MOC, very early assignment for MOC, early assignment for MTC, late assignment for MTC, and very early assignment for MTC. Immediate assignmentThe immediate assignment procedure is initiated every time the MS responds to the paging request or the MS initiates a service request. The purpose of the immediate assignment is to establish the RR connection between the MS and the network. In the immediate assignment procedure, the MS sends a CHANNEL REQUEST message on the random access channel (RACH). The network then responds with an IMMEDIATE ASSIGNMENT message to instruct the MS to access the network through the dedicated channel. This channel can be a stand-alone dedicated control channel (SDCCH) or a TCH. Huawei BSC supports cell-level SDCCH immediate assignment and TCH immediate assignment. Immediate assignment combinationEach immediate assignment from the BSC on the Abis interface includes the response for only one MS's channel request message. The response messages for channel request on the Um interface, however, are of three types: immediate assignment, immediate assignment extended and immediate assignment reject. One immediate assignment extended may include the responses for two immediate assignment messages and one immediate assignment reject may include the immediate assignment commands (reject type) for a maximum of four MSs. To improve the processing efficiency on the Um interface, the BTS encapsulates as many immediate assignment commands as possible into one immediate assignment extended message or immediate assignment reject message on the Um interface and sends it to the MS. This type of processing method is called immediate assignment combination. Early assignment for MOCEarly assignment for MOC is a procedure in which the MOC is assigned a TCH before the call is established. After the immediate assignment is complete, the network sends the assignment command to the MS, requesting the calling party to seize the TCH even if the Altering message is not received. In this case, the ring tone is generated by the network. Late assignment for MOCIn terms of signaling, the network sends the assignment command to the MS only after the Alerting message from the called party is received, requesting the calling party to seize the TCH. In this case, the ring tone is generated by the MS because no TCH is available before the connection is established. Very early assignment for MOCThe very early assignment for MOC is a procedure in which the TCH instead of the SDCCH is assigned to the calling party during the immediate assignment phase. This function increases the service access speed. The system performs the authentication, ciphering, other signaling exchanges, and subsequent call connection procedures on the TCH. After receiving the ASS REQ message from the network, the BSS changes the TCH used for signaling exchanges to a real TCH through the Mode Modify command. Early assignment for MTCEarly assignment for MTC is a procedure in which the MTC is assigned with a TCH before the call is established. In terms of signaling, the MTC establishment is triggered when the Paging Request message from the network is received. After the immediate assignment is complete, the network sends the assignment command to the MS, requesting the called party to seize the TCH even if the Altering message is not received. In this case, the ring tone is generated by the network. Late assignment for MTCIn terms of signaling, the network sends the assignment command to the MS only after the Alerting message is received, requesting the called party to seize the TCH. In this case, the ring tone is generated by the MS because no TCH is available before the connection is established. Very early assignment for MTCThe very early assignment for MTC is a procedure in which the TCH instead of the SDCCH is assigned to the called party during the immediate assignment phase. This function increases the service access speed. The system performs the authentication, ciphering, other signaling exchanges, and subsequent call connection procedures on the TCH. After receiving the ASS REQ message from the network, the BSS modifies the TCH used for signaling exchanges to a real TCH through the Mode Modify command.EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.4.3 GBFD-110503 Call ReestablishmentAvailabilityThis feature is introduced in GBSS6.1.SummaryWhen the MS encounters a radio link failure during the call, the call reestablishment procedure can be used to reestablish the radio link connection so that the original call can proceed.BenefitsThe call is reestablished quickly after a call drop caused by the radio link failure. This mechanism shortens the call intermission, and thus improves the user experience.DescriptionCall reestablishment is a procedure for connection recovery after the MS encounters a radio link failure during the call. Call reestablishment may occur in a new cell or new location area. The initiation of the call reestablishment attempt depends on the call status and whether the cell allows call reestablishment.After detecting a radio link failure, the BTS sends a radio link failure message to the BSC. The BSC then releases the corresponding radio resource and waits for the MS to initiate the call reestablishment.After detecting a radio link failure, the MS sends a Channel Request message for call reestablishment) in the selected cell (the original cell or a new cell) to the BSS. The BSS then initiates and completes the immediate assignment procedure. After the immediate assignment is complete, the MS sends a call reestablishment request to the MSC.The MSC initiates the encryption and assignment procedures. The call establishment is almost complete. The MSC sends a status query message to the MS to confirm whether the call status or attach status matches the status information stored on the MSC. The MS sends the MSC a status message to report the call status or attach status. The call reestablishment is complete.During the call reestablishment, the MS cannot return to idle mode. Therefore, when the MS selects a cell in a different location area as the target cell for call reestablishment, the location updating procedure cannot be performed until this call terminates.The MSC controls the call reestablishment procedure, and the BSC is responsible for the channel establishment and layer 3 message forwarding. Other processing is not required.EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsMSC support is needed.1.4.4 GBFD-112501 TCH Re-assignmentAvailabilityThis feature is introduced in GBSS6.1.SummaryThe TCH re-assignment refers to that the BSC re-assigns a TCH to the MS after a TCH assignment fails.BenefitsThis feature provides the following benefits: Minimizes the impact on the call continuity caused by the TRX channel fault, and thus ensures a successful first dialing. Greatly reduces the assignment failures caused by the frequency interference in a cell, and thus minimizes the impact on the call continuity and improve the service quality.DescriptionDuring a call, the BSC assigns a TCH to the MS after receiving an assignment request message from the MSC. Then, the assignment command is issued to the MS through the Um interface. If the TCH assignment fails because of various causes such as the co-channel interference, the BSC re-assigns another TCH to the MS instead of sending an assignment failure message to the MSC. If the TCH re-assignment is successful, the BSC sends a message to the MSC, indicating that the assignment is complete; otherwise, the BSC sends a message to the MSC, indicating that the assignment fails.EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.5 Radio Resource Management1.5.1 GBFD-111001 TRX ManagementAvailabilityThis feature is introduced in GBSS6.1.SummaryTRX management involves four procedures about the TRX to support the signaling flow on the control plane of layer 3.BenefitsTRX management is a basic feature for the operators to provide the CS speech services. This feature enables the management of the error reporting, flow control, and radio resources of the TRX such as SACCH resources.In Huawei GBSS, this feature can be implemented completely on the BSC side. Thus, the management operations on the BTS are avoided, O&M is simplified, O&M expenditure is reduced, and thereby O&M efficiency is improved.DescriptionTo enable the Abis interface to support the signaling flow on the control plane of layer 3 specified by 3GPP TS 44.018/3GPP TS 24.008, a set of TRX-level service management procedures are provided. This set of procedures is referred to as TRX management. Procedures involved in the TRX management are all completed at the BTS or BSC without being directed to the core network elements. The procedures are as follows: SACCH filling information modification procedureThe BSC informs the BTS of the new system information used on all downlink SACCHs so that the BTS can instruct the MS to initiate the system information updating procedure. Radio resource indication procedureThe BTS informs the BSC of the interference level on the idle dedicated channels of each TRX. Thus, the BSC is completely informed of the interference level of the current idle channels to facilitate subsequent channel assignments. Flow control procedureThe frame unit controller (FUC) on a TRX informs the BSC of the TRX overload due to CCCH overload, AGCH overload, or TRX processor overload. Error reporting procedureThe BTS informs the BSC of the detected downlink errors that cannot be reported by other procedures. EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.5.2 GBFD-111002 Radio Link ManagementAvailabilityThis feature is introduced in GBSS6.1.SummaryRadio link management involves not only the establishment and release of radio links but also the transfer of layer 3 messages.BenefitsRadio link management is a basic feature for the operators to provide the CS speech services. This feature involves the establishment and release of radio links, the transfer of layer 3 messages, and the real-time monitoring of radio links, and thus facilitates the basic radio link management.DescriptionRadio link management, mainly used for the establishment and release of radio links and the message forwarding, manages the data link layer. Through the procedures in the radio link management, the BTS and the BSC can perform channel status management, initial service establishment and service release. The procedures involved in the radio link management are as follows: Link establishment and release proceduresLink establishment indication: Through this procedure, the BTS informs the BSC that the multi-frame link has been established. The BSC establishes an SCCP link to the MSC according to this indication procedure. Link establishment request: Through this procedure, the BSC requests to establish a multi-frame link on the radio path. Link release indication: Through this procedure, The BTS informs the BSC that the radio link release initiated by the MS is complete. Link release request: Through this procedure, the BSC instructs the BTS to release a radio link. Transparent transmission of layer 3 messagesTransmission of a transparent layer 3 message in acknowledged mode: Through this procedure, the BSC instructs the BTS to forward a transparent layer 3 message on the Um interface in acknowledged mode. Reception of a transparent layer 3 message in acknowledged mode: Through this procedure, the BTS informs the BSC that a transparent layer 3 message on the Um interface is received in acknowledged mode. Transmission of a transparent layer 3 message in unacknowledged mode: Through this procedure, the BSC instructs the BTS to forward a transparent layer 3 message in unacknowledged mode. Reception of a transparent layer 3 message in unacknowledged mode: Through this procedure, the BTS informs the BSC that a transparent layer 3 message on the Um interface is received in unacknowledged mode. Notification and handling of the link faultLink error indication: Through this procedure, the BTS informs the BSC of the errors on the radio link layer.EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.5.3 GBFD-111003 Radio Common Channel ManagementAvailabilityThis feature is introduced in GBSS6.1.SummaryRadio common channel management involves the management of common control channels such as PCH, RACH, AGCH, NCH, PPCH, PRACH, and PAGCH.BenefitsRadio common channel management is a basic feature for the operators to provide the CS speech services.Description Common control channelsCommon control channels include PCH, RACH, AGCH, NCH, PPCH, PRACH, and PAGCH.Paging Channel (PCH): Downlink channel. The MS listens to the PCH at intervals to determine whether there is a call request from the MSC.RACH: Uplink channel: The MS accesses the network through the RACH and requests the network to assign an SDCCH.Access Grant Channel (AGCH): Downlink channel. The network informs the MS of the assigned dedicated channel (SDCCH or TCH) through the AGCH.Notification Channel (NCH): Downlink channel, used for voice group call service (VGCS) and voice broadcast service (VBS).Packet Paging Channel (PPCH): Downlink channel. The MS listens to the PPCH at intervals to determine whether there is a packet call to the MS from the SGSN.Packet Random Access Channel (PRACH): Uplink channel. The MS requests for network access through the PRACH.Packet Access Grant Channel (PAGCH): Downlink channel. The network informs the MS of the assigned packet data service channel through the PAGCH. Radio common channel managementThe radio common channel management procedures involve the signaling procedures of MS access and assignment, and also the resource management of the common channel. The involved procedures are as follows: Channel request by MS: This procedure is triggered when the TRX detects a random access request (channel request message) from the MS. Paging: This procedure is used to page an MS on a paging sub-channel. It is used for the MOC and initiated by the MSC through the BSC. The BSC determines the paging group to be used according to the IMSI of the called MS. The values of this paging group are sent to the BTS along with the identity information of the MS. Immediate assignment: When the MS first accesses the BTS, the BSC assigns a dedicated channel for the MS immediately through this procedure. CCCH load indication: The BTS informs the BSC of the load information on a CCCH timeslot. If this load exceeds the load limit predefined in the system, the BTS sends the CCCH overload indication to the BSC periodically.Delete indication: Through this procedure, the BTS informs the BSC that one immediate assignment message is deleted without being put in the AGCH queue due to AGCH overload. To do this, the BTS sends a Delete indication message to the BSC.Broadcast information modification: The BSC informs the BTS of the new information to broadcast on the BCCH. To do this, the BSC sends a BCCH information message to the BTS.Short message cell broadcast: Through this procedure, the BSC instructs the BTS to send the cell broadcast short message. VGCS establishment notification: On receiving the VGCS ASSIG REQ message from the CN, the BSC establishes a VGCS channel immediately or later based on the strategy information in the VGCS ASSIG REQ message. Then, the BSC sends the Notification information to the BTS. The BTS then sends this information to the MS. On receiving this information, the MS responds to the information accordingly.EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.5.4 GBFD-111004 Radio Dedicated Channel ManagementAvailabilityThis feature is introduced in GBSS6.1.SummaryRadio dedicated channel management involves the assignment, activation, release, management, and reporting of the dedicated channels such as SDCCH, SACCH, and TCH.BenefitsRadio dedicated channel management is a basic feature for the operators to provide the CS speech services.DescriptionRadio dedicated channel management involves the assignment, activation, release, management, and reporting of the dedicated channels such as SDCCH, SACCH, and TCH. The involved procedures are as follows:Channel activation: Through this procedure, the BSC instructs the BTS to activate a dedicated channel for an MS. After this channel is activated, the BSC assigns this channel to the MS through the Immediate Assign, Assign Command, Additional Assign or Handover Command message. Channel mode modification: Through this procedure, the BSC instructs the BTS to change the mode of an activated channel. Handover detection: This procedure is used to detect the access of the switched MS between the target BTS and the target BSC. Start of encryption: This procedure is used to initiate the encryption procedure specified by GSM TS 04.08. Measurement reporting: This procedure consists of the mandatory basic measurement reporting procedure and the optional measurement reporting procedure with pre-processing. Through these two procedures, the BTS reports to the BSC all the parameters related to handover decision. SACCH deactivation: Through this procedure, the BSC deactivates the related SACCH of a TRX according to the requirement of the channel release procedure specified by GSM TS 04.08. Radio channel release: Through this procedure, the BSC instructs the BTS to release a radio channel that is not in use. MS power control: Through this procedure, the BSS controls the transmit power of the MS related to an activated channel. The MS power control decision should be implemented on the BSC or BTS. BTS transmit power control: Through this procedure, the BSS controls the transmit power of the activated channel on the TRX. BSS transmit power control should be implemented on the BSC or BTS. Connection failure: Through this procedure, the BTS informs the BSC that an activated dedicated channel is disconnected. SACCH information modification: Through this procedure, the BSC instructs the BTS to change the filling information (system information) on an SACCH. Talker detection: During a VGCS call, on receiving the Talker uplink access from the MS on the idle uplink VGCS channel, the BTS constructs the VGCS UPLINK GRANT message on the activated dedicated channel and reports to the BSC the detected Access delay received from the MS.Listener detection: When there is no listener in the cell, the dedicated radio downlink channel allocated to the VGCS/VBS should be released timely to improve the resource utilization. The BSC periodically broadcasts the Uplink free message in the cell. After all the listeners receive this message, a Talker uplink access message is sent to the BTS on the idle uplink VGCS channel. The BTS constructs the VGCS UPLINK GRANT message on the activated dedicated channel and sends a listener detection message to the BSC. The BTS uses this message to inform the BSC of the Access delay detected on the MS.EnhancementNoneDependencyImpacts on the BSC hardwareNoneImpacts on the BTS hardwarePlease refer to the BTS Dependency of feature list.Dependency on other features of the GBSSNoneDependency on other NEsNone1.5.5 GBFD-111005 Enhanced Channel Assignment AlgorithmAvailabilityThis feature is introduced in GBSS6.1.SummaryEnhanced channel assignment algorithm is adopted to allocate the optimum channel based on various factors.BenefitsBy taking into account of various factors, this feature enables the BSS to allocate the optimum channel to each call, and hence ensures better voice quality for subscribers.This feature enables the BSS to provide as many services as possible by using limited channel resources, thus maximizing the service capacity of the network.Description Channel assignment priorities:Enhanced channel assignment algorithm is adopted for the selection of an optimum channel. Each channel is assigned with a priority level. The channel of lower priority level is less likely to be allocated than the channel of higher priority level.Enhanced channel assignment algorithm provides four types of priority levels: capacity, quality, PS coordination, and management. The four types of priorities work together and form the overall priority of each radio channel. A higher overall priority value indicates a higher priority level and an earlier assignment of the radio resource accordingly. Four factors are considered in determining the priority level: capacity, quality, PS coordination, and management. The priority