Datasets:
OrganizedProgrammers
/
ETSISpecContent

Dataset card Data Studio Files Community
1
hash
stringlengths
32
32
doc_id
stringlengths
7
13
section
stringlengths
3
121
content
stringlengths
0
3.58M
e1df81e32c85ac85801df65e6181a587
100 596
9.3.44 SMSCB Channel Indicator
This element is used to indicate the CB channel [see GSM 05.02] to be used for broadcasting the data. 8 7 6 5 4 3 2 1 Element identifier 1 Spare Channel Ind 2 This element is used to indicate the CB channel to be used for broadcasting the data. The Channel Ind field is coded as follows: Value Channel Ind 0 0 0 0 Basic CBCH 0 0 0 1 Extended CBCH (supporting the extended CBCH by the network or MSs is optional) all other values are reserved. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 80 (GSM 08.58 version 7.4.1 Release 1998)
e1df81e32c85ac85801df65e6181a587
100 596
9.3.45 Group call reference
It is coded as follows: 8 7 6 5 4 3 2 1 Element identifier 1 Length 2 Descriptive group or broadcast call reference 3-8 The octets 3 to 8 are coded in the same way as the octets 1-6 in the Descriptive group or broadcast call reference information element as defined in GSM 04.08.
e1df81e32c85ac85801df65e6181a587
100 596
9.3.46 Channel description
This is a variable length element used to pass a radio interface information element from BSC to BTS. 8 7 6 5 4 3 2 1 Element identifier 1 Length 2 Group Channel Description 3-n Octet j (j = 3, 4, ..., n) is the unchanged octet j-2 of a radio interface Group Channel description information element as defined in GSM 04.08, n-2 is equal to the length of the radio interface Group channel description information element.
e1df81e32c85ac85801df65e6181a587
100 596
9.3.47 NCH DRX information
This is a variable length element used to pass a radio interface information element from BSC to BTS. 8 7 6 5 4 3 2 1 Element identifier 1 Length 2 NCH DRX information 3 Octet 3 bits 1 and 2 are bits 1 and 2 of the radio interface NLN as defined in GSM 04.08. Octet 3 bits 3, 4 and 5 are bits 1, 2 and 3 of the radio interface eMLPP priority as defined in GSM 04.08. Octet 3 bit 6 is the NLN status parameter as defined in GSM 04.08. Octet 3 bits 7 and 8 are spare and set to zero.
e1df81e32c85ac85801df65e6181a587
100 596
9.3.48 Command indicator
8 7 6 5 4 3 2 1 Element identifier 1 Length 2 E Command Value 3 Command Extension 3a The Command Value is a single octet field (octet 3) if the extension bit E (bit 8) is set to 0. If it is set to 1 then the Command value is a 2 octet field (octets 3 and 3a). ETSI ETSI TS 100 596 V7.4.1 (2000-05) 81 (GSM 08.58 version 7.4.1 Release 1998) COMMAND VALUES: Value Command 0 0 0 0 0 0 0 Start 0 0 0 0 0 0 1 Stop 0 0 0 0 0 1 0 reserved for international use 0 : : : : : : 1 0 0 0 0 0 0 1 0 0 0 0 0 1 reserved for national use 1 : : : : : : 1 1 1 1 1 1 1
e1df81e32c85ac85801df65e6181a587
100 596
9.3.49 eMLPP Priority
This Information Element contains the eMLPP priority of the call. It is coded as follows: 8 7 6 5 4 3 2 1 Element identifier 1 spare call priority 2 The call priority field (bit 3 to 1 of octet 2) is coded in the same way as the call priority field (bit 3 to 1 of octet 5) in the Descriptive group or broadcast call reference information element as defined in GSM 04.08.
e1df81e32c85ac85801df65e6181a587
100 596
9.3.50 UIC
It is coded as follows: 8 7 6 5 4 3 2 1 Element identifier 1 Length 2 UIC information 3 Octet 3 bits 1 to 6 contain the radio interface octet 2 bits 3 to 8 of the UIC information element as defined in GSM 04.08. Octet 3 bits 7 and 8 are spare and set to zero.
e1df81e32c85ac85801df65e6181a587
100 596
9.3.51 Main channel reference
This element contains the main channel reference of a multislot connection. It is coded in two octets as follows: 8 7 6 5 4 3 2 1 Element identifier 1 Reserved for future use TN 2 TN is time slot number, binary represented as in GSM 05.02. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 82 (GSM 08.58 version 7.4.1 Release 1998)
e1df81e32c85ac85801df65e6181a587
100 596
9.3.52 MultiRate configuration
This element gives the description of the multirate speech codec configuration to be applied. 8 7 6 5 4 3 2 1 Element identifier 1 Length 2 Rest of element coded as in GSM 04.08 not including GSM 04.08 element identifier or GSM 04.08 octet length value 3-n
e1df81e32c85ac85801df65e6181a587
100 596
9.3.53 MultiRate Control
This element indicates whether TFO is enabled or not and whether the BSC authorises the BTS to perform autonomously multi-rate codec changes and whether an handover is to be expected. It is coded in two octets as follows: 8 7 6 5 4 3 2 1 Element identifier 1 Spare PRE RAE TFO 3 The TFO field (bit 1 of octet 3) indicates if TFO is enabled or not. It is coded as follows: Value TFO 0 Tandem Free Operation is enabled 1 Tandem Free Operation is disabled The RAE field (bits 2-3, octet 3) defines whether the RATSCCH mechanism is enabled or not. It is coded as follows: Value RAE 0 0 RATSCCH mechanism is generally enabled, the BTS may change the AMR configuration within the given SCS and MACS constraints and within the given radio and Abis channel. 0 1 RATSCCH mechanism will potentially be enabled for one exchange. The BSC will use a MultiRate CODEC MOD REQ message for that purpose 1 0 reserved 1 1 RATSCCH mechanism is generally disabled The PRE field (bit 4 of octet 3) indicates if an handover is to be expected soon or not. It is coded as follows: Value PRE 0 Handover is not expected, respectively has failed 1 Handover is expected soon
e1df81e32c85ac85801df65e6181a587
100 596
9.3.54 Supported Codec Types
This element indicates the codec types supported by the BSS or remote BSS. It is coded as follows: 8 7 6 5 4 3 2 1 Element identifier 1 Length 2 Sys-ID 3 ext Codec List 4-n Preferred Codec Type n+1 The Sys-ID field (octet 3) identifies the system that sends or has sent the configuration. It should be set to 0000 0000 for GSM. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 83 (GSM 08.58 version 7.4.1 Release 1998) The Codec List field (octet 4) lists the codec types that are supported by the BSS and Transcoder, and are therefore potential candidates for TFO establishment. If the Preferred Codec Type is not present (this field is set to “1111.1111”), then the Codec List belongs to the remote BSS, otherwise it is the list of alternative Preferred Codec Types. It is coded as follows: Bit 1: Set to 1 if the GSM FR Speech Codec is supported. Bit 2: Set to 1 if the GSM HR Speech Codec is supported. Bit 3: Set to 1 if the GSM EFR Speech Codec is supported. Bit 4: Set to 1 if the GSM FR AMR Speech Codec is supported. Bit 5: Set to 1 if the GSM HR AMR Speech Codec is supported Bit 6-7: Reserved, set to 0. Bit 8: Reserved for extension, set to 0. If bit 4 of the Codec List field (octet 4) indicates that FR AMR is supported or if bit 5 of the Codec List field (octet 4) indicates that HR AMR is supported, the following two octets (octets 5-6) should be coded as follows: 8 7 6 5 4 3 2 1 Spare TFO_VER MACS 5 SCS 6 If both FR AMR and HR AMR are supported, the octets 5-6 shall be sent twice. The first occurrence shall correspond to FR AMR configuration, the second one shall correspond to HR AMR configuration. The MACS field (bits 1-2 of octet 5, if present) indicates the Maximum number of AMR Codec ModeS the BSS can support in the Active Codec Set. It should be coded as follows: 0 0: A maximum of four codec modes can be supported in the Active Codec Set 0.1: A maximum of one codec mode can be supported in the Active Codec Set 1.0: A maximum of two codec modes can be supported in the Active Codec Set 1.1: A maximum of three codec modes can be supported in the Active Codec Set The TFO_VER field (bits 3-4 of octet 5, if present) indicates the TFO_VERSION. 0 0 : Version 0 of TFO All other values reserved for future used The SCS field (octet 6 if present) indicates the Set of AMR Codec modes Supported by the BSS. It should be coded as follows: Bit 8: Set to 1 if the AMR 12.2 Codec Mode is supported. Bit 7: Set to 1 if the AMR 10.2 Codec Mode is supported. Bit 6: Set to 1 if the AMR 7.95 Codec Mode is supported. Bit 5: Set to 1 if the AMR 7.40 Codec Mode is supported. Bit 4: Set to 1 if the AMR 6.70 Codec Mode is supported. Bit 3: Set to 1 if the AMR 5.90 Codec Mode is supported. Bit 2: Set to 1 if the AMR 5.15 Codec Mode is supported. Bit 1: Set to 1 if the AMR 4.75 Codec Mode is supported. The Preferred Codec Field (bits 1-8, octet n+1) indicates the preferred codec type for TFO establishment. It is coded as follows; 0 0 0 0 . 0 0 0 0: Full Rate Codec is preferred 0 0 0 0 . 0.0 0 1: Half Rate Codec is preferred 0 0 0 0 . 0 0 1.0: Enhanced Full Rate Codec is preferred 0 0 0 0 . 0 0 1.1: FR Adaptive Multi-Rate Codec is preferred 0 0 0 0 . 0 1 0 0: HR Adaptive Multi-Rate Codec is preferred 1 1 1 1 . 1 1 1 1: No preferred codec type All other values reserved for future used ETSI ETSI TS 100 596 V7.4.1 (2000-05) 84 (GSM 08.58 version 7.4.1 Release 1998) 9.3.55 Codec Configuration This element indicates the active codec in the BSS or the remote BSS It is coded as follows: 8 7 6 5 4 3 2 1 Element identifier 1 Length 2 Active Codec Type 3 The Active Codec Type field (bits 1-8, octet 3) indicates the type of codec in use. It is coded as follows: 0 0 0 0 . 0 0 0 0: Full Rate Codec in use 0 0 0 0 . 0 0 0 1: Half Rate Codec in use 0 0 0 0 . 0 0 1 0: Enhanced Full Rate Codec in use 0 0 0 0 . 0 0 1 1: FR Adaptive Multi Rate Codec in use 0 0 0 0 . 0 1 0 0: HR Adaptive Multi Rate Codec in use All other values are reserved for future use If the Active Codec Type field (octet 3) indicates that AMR (FR or HR) is the active codec type, then the following two octets (octets 4-5) shall provide the configuration in use. They shall be coded as follows: 8 7 6 5 4 3 2 1 Spare ICM 4 Active Codec Set 5 The ICM field (bits 1-2, octet 4) defines the Initial Codec Mode. It is coded as defined in the GSM 05.09, section 3.4.1. The Active Codec Set (octet 5) defines the set of AMR codec modes used in the active set. It is coded as defined for the Set of AMR codec modes in the Multi-Rate configuration IE in the GSM 04.08, section 10.5.2.21aa.
e1df81e32c85ac85801df65e6181a587
100 596
9.3.56 Round Trip Delay
This element indicates the value of the calculated round trip delay between the BTS and the transcoder, or between the BTS and the remote BTS, if TFO is established. It is coded in 2 octets as follows: 8 7 6 5 4 3 2 1 Element identifier 1 RTD Delay IND 2 The RTD field is the binary representation of the value of the round trip delay in 20 ms increments. The Delay IND field indicates if the delay corresponds to a BTS to transcoder delay or to a BTS to remote BTS delay. It is coded as follows: Value Delay IND 0 The RTD field contains the BTS-Transcoder round trip delay 1 The RTD field contains the BTS-Remote BTS round trip delay ETSI ETSI TS 100 596 V7.4.1 (2000-05) 85 (GSM 08.58 version 7.4.1 Release 1998)
e1df81e32c85ac85801df65e6181a587
100 596
9.3.57 TFO Status
This element indicates if TFO is established. It is coded in 2 octets as follows : 8 7 6 5 4 3 2 1 Element identifier 1 Spare TFO 2 The TFO field shall be coded as follows : Value TFO 0 TFO is not established 1 TFO is established
e1df81e32c85ac85801df65e6181a587
100 596
9.3.58 LLP APDU
This is a variable length element that conveys an embedded message or message segment associated with the higher level protocol LLP, as defined in GSM 04.71. This element can be sent from the BSC to the BTS or to the Standalone Type B LMU, and vice versa. 8 7 6 5 4 3 2 1 Element identifier 1 Length 2 The rest of the information element contains the embedded message that contains a Facility Information Element as defined in GSM 04.71 excluding the Facility IEI and length of Facility IEI octets defined in GSM 04.71. 3-n ETSI ETSI TS 100 596 V7.4.1 (2000-05) 86 (GSM 08.58 version 7.4.1 Release 1998) Annex A (informative): Document change history SMG# Spec CR Rev Cat Ph Vers New Vers Subject s28 08.58 A027 1 B R98 6.1.0 7.0.0 Introduction of AMR s29 08.58 A030 B R98 7.0.0 7.1.0 Addition of new system information messages for SoLSA support s29 08.58 A034 A R98 7.0.0 7.1.0 Wrong application of an approved CR S30 08.58 A042 A R98 7.1.0 7.2.0 L3 Info IE length in SACCH INFO MODIFY and FILLING S30 08.58 A044 B R98 7.1.0 7.2.0 Introduction of the AMR SMG2 TRAU/SMG11 TFO S30bis 08.58 A048 B R98 7.2.0 7.3.0 TFO AMR S31 08.58 A047 3 C R98 7.3.0 7.4.0 Addition of LCS message - 08.58 - - - R98 7.4.0 7.4.1 Editorial correction to Change History and graphics update for font compatibility ETSI ETSI TS 100 596 V7.4.1 (2000-05) 87 (GSM 08.58 version 7.4.1 Release 1998) History Document history V7.1.0 July 1999 Publication V7.3.0 December 1999 Publication V7.4.1 May 2000 Publication
10b5e06b1903c8b93c1db34a5ea49830
100 595
1 Scope
The present document specifies the link layer used for signalling on the A-bis interface between BSC and BTS. The use and general aspects of the A-bis interface are described in GSM 08.51 and the interface aspects in GSM 08.52. The Link Access Procedure on the D-channel (LAPD) specification used on the A-bis interface in the GSM PLMN is a subset of the ETS 300 125 which in turn has less options than the CCITT Recommendation Q.921. This description contains first the protocol definitions and second the services provided by the layer 2 to the layer 3.
10b5e06b1903c8b93c1db34a5ea49830
100 595
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present document. • References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. • For a specific reference, subsequent revisions do not apply. • For a non-specific reference, the latest version applies. • A non-specific reference to an ETS shall also be taken to refer to later versions published as an EN with the same number. • For this Release 1998 document, references to GSM documents are for Release 1998 versions (version 7.x.y). [1] GSM 01.04: "Digital cellular telecommunications system (Phase 2+); Abbreviations and acronyms". [2] GSM 08.51: "Digital cellular telecommunications system (Phase 2+); Base Station Controller (BSC) to Base Transceiver Station (BTS) interface General aspects". [3] GSM 08.52: "Digital cellular telecommunications system (Phase 2+); Base Station Controller (BSC) to Base Transceiver Station (BTS) Interface principles". [4] GSM 12.00: "Digital cellular telecommunications system (Phase 2+); Objectives and structure of Network Management (NM)". [5] GSM 12.01: "Digital cellular telecommunications system (Phase 2+); Common aspects of GSM Network Management (NM)". [6] GSM 12.07: "Digital cellular telecommunications system (Phase 2+); Operations and performance management". [7] GSM 12.02: "Digital cellular telecommunications system (Phase 2+); Subscriber, Mobile Equipment (ME) and services data administration". [8] GSM 12.03: "Digital cellular telecommunications system (Phase 2+); Security management". [9] GSM 12.04: "Digital cellular telecommunications system (Phase 2+); Performance data measurements". [10] GSM 12.05: "Digital cellular telecommunications system (Phase 2+); Subscriber related event and call data". [11] GSM 12.06: "Digital cellular telecommunications system (Phase 2+); GSM Network change control". [12] GSM 12.10: "Digital cellular telecommunications system (Phase 2+); Maintenance provisions for operational integrity of Mobile Stations (MS)". ETSI ETSI TS 100 595 V7.0.0 (1999-08) 6 (GSM 08.56 version 7.0.0 Release 1998) [13] GSM 12.11: "Digital cellular telecommunications system (Phase 2+); Maintenance of the Base Station System (BSS)". [14] GSM 12.13: "Digital cellular telecommunications system (Phase 2+); Maintenance of the Mobile- services Switching Centre (MSC)". [15] GSM 12.14: "Digital cellular telecommunications system (Phase 2+); Maintenance of location registers". [16] GSM 12.20: "Digital cellular telecommunications system (Phase 2+); Network Management (NM) procedures and messages". [17] GSM 12.21: "Digital cellular telecommunications system (Phase 2+); Network Management (NM) procedures and message on the A-bis interface". [18] GSM 12.22: "Digital cellular telecommunications system (Phase 2+); Interworking of GSM Network Management (NM) procedures and messages at the Base Station Controller (BSC)". [19] CCITT Recommendation Q.921: "Integrated services digital network (ISDN) user-network interface - Data link layer specification". [20] ETS 300 125: "Integrated Services Digital Network (ISDN); User-network interface data link layer specification Application of CCITT Recommendations Q.920/I.440 and Q.921/I.441".
10b5e06b1903c8b93c1db34a5ea49830
100 595
3 Definitions and abbreviations
The following abbreviations and acronyms are used in the present document. Ai Action indicator BCF Base Station Control Function BSC Base Station Controller BTS Base Transceiver Station C/R Command/Response field bit GSM Global System for Mobile communication L2ML Layer 2 Management Link LAPD Link Access Procedure on the D-Channel MPH- Communication between Management and PHysical layer MS Mobile Station N(S) Send sequence variable O&M Operation and Maintenance OML Operation and Maintenance Link PH- Communication between data link layer and PHysical layer PLMN Public Land Mobile Network Ri Reference number RSL Radio Signalling Link SAP Service Access Point SAPI Service Access Point Identifier SMS Short Message Service TEI Terminal Endpoint Identifier TRX Transceiver XID EXchange IDentification ETSI ETSI TS 100 595 V7.0.0 (1999-08) 7 (GSM 08.56 version 7.0.0 Release 1998)
10b5e06b1903c8b93c1db34a5ea49830
100 595
4 General description
The following information categories are supported by the procedures of this layer 2 Recommendation: - signalling (including Short Message Service (SMS) information); - operation and maintenance; - layer 2 management. For each of these categories the BSC may have one or more layer 2 links to every TRX and BCF. The signalling links over the A-bis interface are addressed to the different units by Terminal Endpoint Identifiers (TEI). The same unit will normally have more than one functional entity. The logical links between different functional entities are identified by functional addresses, the Service Access Points Identifier (SAPI). Figure 1 shows the architectural model with different layer 2 links. A number of logical links may be multiplexed on each physical link. The same layer 2 logical link may not be distributed over more than one physical link. ____________________ | ________ | | | | | | | | __ | __ ______ | | || |_______RSL________SAPI_=_0___| |__| | | | || |_______OML________SAPI_=_62__| |__| | | | || |_______L2ML_______SAPI_=_63__| |__| TRX |TEI 1 | | || | | |__| | | | ||__| |__| |______| | |LAYER 2| | __ ______ | | | __ | | |__| | | | || |_____|_RSL________SAPI_=_0___| |__| | | | || |_______OML________SAPI_=_62__| |__| TRX |TEI 2 | | || |_______L2ML_______SAPI_=_63__| |__| | | | T E I || | | | |______| | | || |_______RSL________SAPI_=_0___| | ______ | | || |_______OML________SAPI_=_62__| |__| | | | || |_______L2ML_______SAPI_=_63__| |__| | | | ||__| | |__| TRX |TEI 3 | | | | | |__| | | |MANAGE-| | |__| |______| | |MENT | __ | __ ______ | | || |_______OML________SAPI_=_62__| |__| | | | || |_______L2ML_______SAPI_=_63__| |__| BCF |TEI 4 | | ||__| |__| | | | | | __ _ | __ | | | | || | _ _ | OML _ _ _ _SAPI = 62_ | |__| |TEI 65 | | || | _ _ | L2ML_ _ _ _SAPI = 63_ | |__| | | |_______||__| | |__| |______| | | |___________________| Figure 1: An example of Logical Layer 2 links supported by three permanent and one semipermanent links ETSI ETSI TS 100 595 V7.0.0 (1999-08) 8 (GSM 08.56 version 7.0.0 Release 1998)
10b5e06b1903c8b93c1db34a5ea49830
100 595
5 Functional contents
The basic functional content of the layer 2 protocol is: - transparent layer 2 links and time fill; - point-to-point dedicated layer 2 links addressing both physical entities and functional entities; - point-to-multipoint addressed links used for layer 2 management; - basic functions for TEI assignment and management; - basic priority functions; - basic supervision of links when not carrying traffic; - sequence control; - transmission error control; - control of errors not recoverable by retransmission.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6 LAPD functions
The LAPD functions as specified in ETS 300 125 are applicable. However, the exceptions and modifications specified in the remainder of the present document shall be used.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1 Exceptions and modifications
In the following headlines from ETS 300 125 are kept and references are made to the corresponding subclause of ETS 300 125.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.2 Command/Response field bit (C/R)
(Refer to ETS 300 125, part 2, subclause 3.3.2) In GSM PLMN's BSC represents the network side and TRX/BCF the user side of the interface.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.3 Service Access Point Identifier (SAPI)
(Refer to ETS 300 125, part 2, subclause 3.3.3) The SAPI values for the A-bis interface are as listed in table 1. ETSI ETSI TS 100 595 V7.0.0 (1999-08) 9 (GSM 08.56 version 7.0.0 Release 1998) Table 1: Allocation of SAPI values and priority classes __________________________________________________________________________________ | | | | | SAPI | Related layer 3 or layer management entity | Priority | | value | | | |___________|________________________________________________________|____________| | | | | | 0 | Radio signalling procedures | 2 | | | | | | 1 | Reserved for packet mode communications using Q.931 | - | | | call control procedures (Not used in GSM PLMN) | | | | | | | 16 | Reserved for packet communication conforming to X.25 | - | | | level 3 procedures (Not used in GSM PLMN) | | | | | | | 62 | Operation and maintenance procedures | 1 | | | | | | 63 | Layer 2 management procedures | 1 | | | | | |All others | Reserved for future standardization | - | |___________|________________________________________________________|____________|
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.4 TEI for point-to-point data link connection
(Refer to ETS 300 125, part 2, subclause 3.3.4.2) The remaining Terminal Endpoint Identifier (TEI) values are used for the point-to-point data link connections associated with the addressed Service Access Point (SAP). The range of TEI values shall be allocated as shown in table 2. Table 2: Allocation of TEI values ____________________________________________________________________ |TEI | User type | |value____|_________________________________________________________| | | | |0 - 63 | TEI assignment for fixed TRX and BCF addresses. | | | | |64 - 126 | TEI assignment for additional, TRX or BCF addresses. | |_________|_________________________________________________________| NOTE: A BCF is given a separate layer 2 link only if it is not integrated with a TRX.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.5 Commands and responses
(Refer to ETS 300 125, part 2, subclause 3.6.1) The XID command and response are not used.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.6 Exchange identification (XID) command/response
(Refer to ETS 300 125, part 2, subclause 3.6.12) This functionality is not used.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.7 MDL-XID
(Refer to ETS 300 125, part 2, subclause 4.1.1.9) This functionality is not used.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.8 PH-DATA, PH DEACTIVATE and PH-ACTIVATE
(Refer to ETS 300 125, part 2, subclauses 4.1.1.10 - 4.1.1.12) This functionality is not relevant. ETSI ETSI TS 100 595 V7.0.0 (1999-08) 10 (GSM 08.56 version 7.0.0 Release 1998)
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.9 MPH-ACTIVATE, MPH-DEACTIVATE an MPH-INFORMATION
(Refer to ETS 300 125, part 2, subclauses 4.1.1.13 - 4.1.1.15) This functionality is not relevant.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.10 Priority indicator
(Refer to ETS 300 125, part 2, subclause 4.1.3.1) The different SAPIs are given the priority classes as listed in table 1 when contending (with priority one as the highest).
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.11 Terminal Endpoint Identifier (TEI) management procedures
(Refer to ETS 300 125, part 2, subclause 5.3) Due to the special assignment functions needed on the A-bis interface there are modifications and additions to the assignment procedures. The rest of subclause 5.3 in ETS 300 125, part 2, is kept if not stated otherwise.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.11.1 General
(Refer to ETS 300 125, part 2, subclause 5.3.1) TEI management for A-bis interface is based on the following procedural means: - a Subset of the TEI assignment procedures; - the TEI check procedures; - the TEI remove procedures; - an additional TEI assignment procedure. The TEI management needs procedures to check the used TEI values and procedures for reaction in situation where more than one TRX equipment uses the same TEI value. In addition to the fixed values it shall be possible to use additional TEI value to the same TRX equipment and thus increase the signalling capacity.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.11.2 TEI assignment procedure
(Refer to ETS 300 125, part 2, subclause 5.3.2) The TEI assignment procedure used on the A-bis interface has some additions to the automatic TEI assignment procedure specified in ETS 300 125, part 2. To facilitate the configuration control in the BSC each TRX will have a fixed TEI and possibly get access to one or more additional TEIs assigning physical channels/layer 2 links. The layer 2 links may all be turned on and off according to the normal automatic TEI assignment scheme but the TRX may only request identified TEI values which is (semi-) permanently programmed or programmed by operation and maintenance messages. In GSM the reference number Ri is not used. It is only misoperation situations resulting from double failures that could be prevented/solved faster by this parameter. The marginal advantage is not supposed to motivate the application of a random generator and the checking procedure. The subset of the automatic assignment procedure applicable for the first layer 2 link to a TRX shall have the following modifications to ETS 300 125, part 2: - the identity request shall have an Ai value in the range 0-63 identifying the TEI value which is requested for activation; - on reception of the identity request message the BSC will check that the requested TEI may be used from the configurations aspects and then perform a normal TEI check procedure to prevent a double assignment; - if the TEI request is accepted an identity assigned message with the requested TEI number is received by TRX before the expiry of timer T202; ETSI ETSI TS 100 595 V7.0.0 (1999-08) 11 (GSM 08.56 version 7.0.0 Release 1998) - a successful assignment procedure is shown in figure 2. TRX BSC | | | | Identity request (Ai) | | | | | | Identity check request (Ai) | | | | | | | | | Normal | | | | | identity | | | T202 | | check | | T201 | | | procedure | | | | | No answer | | | | | | | V | Identity assigned (Ai) | V | | If timer T201 expires the request shall be repeated once and timer T201 restarted Figure 2: A successful assignment procedure If timer T202 expires the assignment procedure did not succeed, and the TRX will take further actions in accordance with the procedures as specified in ETS 300 125, part 2. If within the assignment procedure an identity check response is received, then the requested TEI value is already in use. There shall be no answer to the requesting TRX and an error indication shall be sent to O&M. An example of a non-successful assignment procedure is shown in figure 3. TRX BSC | | | | Identity request (Ai) | | | | T202 | | Identity check request (Ai) | | | | | T201 | | Identity check response (Ai) | V | | | V | | | | If timer T201 expires the request shall be repeated once and timer T201 restarted Figure 3: An example of assignment in error case (TEI value already in use) The additional TEI assignment procedure is equivalent to the normal one with two exceptions: - the TEI value is in the range: 64-126; - the TEI value and the identification of which physical link it shall operate on is transmitted to the TRX from BSC in an operation and maintenance message. This layer 3 O&M message is transferred on an already assigned layer 2 link. (See 12-series of GSM Technical Specifications). The successful additional assignment procedure is shown in figure 4. TRX BSC | | | O&M command (Ai, physical address) | | | | | | Identity request (Ai) | | | | | | Identity check request (Ai) | | | | | | | | | Identity check | | T202 | | | Procedure | | | T201 | | with no response from | | | | | the TRX side | | | | | | | V | Identity assigned (Ai) | V | | If timer T201 expires the request shall be repeated once and timer T201 restarted Figure 4: The procedure for assigning an additional TEI to a TRX or BCF ETSI ETSI TS 100 595 V7.0.0 (1999-08) 12 (GSM 08.56 version 7.0.0 Release 1998)
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.11.3 TEI identity verify procedure
(Refer to ETS 300 125, part 2, subclause 5.3.5) This procedure is not used.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.11.4 Formats and codes.
(Refer to ETS 300 125, part 2, subclause 5.3.6) All messages except Identity verify and Identity denied are used. The Ai is used as described in subclause 6.1.11.2, the modification to ETS 300 125, part 2, subclause 5.3.2. The Ri parameter is not used and will always be coded 0000 0000. The coding of each field of the various messages is specified in table 3. Table 3: Codes for messages concerning TEI management procedures __________________________________________________________________________ | |Layer | | | | | Message |management |Reference |Message | Action indicator | | name |entity | number | type | Ai | |__________________|identifier_|__Ri______|__________|_____________________| | | | | | | |Identity request |0000 1111 |Not used |0000 0001 |Ai = 0-126 | |(user to network) | |(coded 0) | | | |__________________|___________|__________|__________|_____________________| | | | | | | |Identity assigned |0000 1111 |Not used |0000 0010 |Ai = 0-126 | |(network to user) | |(coded 0) | |Assigned TEI value | |__________________|___________|__________|__________|_____________________| | | | | | | |Identity | | | |Ai = 127 | |check request |0000 1111 |Not used | |Check all TEI values | |(network to user) | |(coded 0) |0000 0100 |---------------------| | | | | |Ai = 0-126 | | | | | |TEI value to be | |__________________|___________|__________|__________|__________checked____| | | | | | | |Identity | | | |Ai = 0-126 | |check response |0000 1111 |Not used |0000 0101 |TEI value in use | |(user to network) | |(coded 0) | | | |__________________|___________|__________|__________|_____________________| | | | | | | |Identity remove |0000 1111 |Not used |0000 0110 |Ai = 127 | |(network to user) | |(coded 0) | |Request for removal | | | | | |of all TEI values | | | | | |---------------------| | | | | |Ai = 0-126 | | | | | |TEI value to be | | | | | | removed | |__________________|___________|__________|__________|_____________________|
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.12 Automatic negotiation of data link layer parameters
(Refer to ETS 300 125, part 2, subclause 5.4 and annex IV) The procedures are not supported.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.13 Establishment procedures
(Refer to ETS 300 125, part 2, subclause 5.5.1.2) The timer T203 shall be implemented in the equipment on both sides of interface A-bis.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.14 N(S) sequence error
(Refer to ETS 300 125, part 2, subclause 5.8.1 and appendix I) As it is the case in ETS 300 125, the optional procedure for retransmission as described in Appendix I is not supported. ETSI ETSI TS 100 595 V7.0.0 (1999-08) 13 (GSM 08.56 version 7.0.0 Release 1998)
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.15 List of system parameters
(Refer to ETS 300 125, part 2, subclause 5.9) All the default values are given in the following subclauses.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.15.1 Timer T200
(Refer to ETS 300 125, part 2, subclause 5.9.1) The default value of timer T200 is 240 ms starting from the end of a transmitted frame. NOTE: This timer depends on the timer values used for supervising the message flow between the Mobile Station (MS) and the network. The proper operation of the procedure requires timer T200 to be greater than the maximum time between transmission of command frames and the reception of their corresponding response or acknowledgement frames and shorter than the shortest layer 3 timer used for supervising this message flow.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.15.2 Maximum number of retransmissions (N200)
(Refer to ETS 300 125, part 2, subclause 5.9.2) The default value of (N200) is 3.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.15.3 Maximum number of octets in an information field (N201)
(Refer to ETS 300 125, part 2, subclause 5.9.3) The default and maximum value of (N201) is 260 octets for all SAPI values. 6.1.15.4 Maximum number of transmission of the TEI identity request message (N202) (Refer to ETS 300 125, part 2, subclause 5.9.4) Not used (i.e. equivalent to infinity).
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.15.5 Maximum number of outstanding frames (K)
(Refer to ETS 300 125, part 2, subclause 5.9.5) For the SAPI value 0 identifying radio signalling the default (K) value shall be 2. For all other SAPIs the value shall be set to the fixed value of 1. NOTE: The value of K for SAPI value 0 shall always be greater than the k value for the other SAPIs.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.15.6 Timer T201
(Refer to ETS 300 125, part 2, subclause 5.9.6) Timer T201 shall have the default value 1 second.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.15.7 Timer T202
(Refer to ETS 300 125, part 2, subclause 5.9.7) The minimum time between the transmission of TEI Identity request messages is a system parameter (T202) which shall be set to 15 seconds.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.15.8 Timer T203
(Refer to ETS 300 125, part 2, subclause 5.9.8) The timer T203 represents the maximum time allowed without frames being exchanged for each TEI. The value of timer T203 shall be 10 seconds. ETSI ETSI TS 100 595 V7.0.0 (1999-08) 14 (GSM 08.56 version 7.0.0 Release 1998)
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.16 Data link layer monitor function
(Refer to ETS 300 125, part 2, subclause 5.10) The supervisory function will be used in the equipment on both sides of the A-bis interface.
10b5e06b1903c8b93c1db34a5ea49830
100 595
6.1.17 Miscellaneous
(Refer to ETS 300 125, part 2, appendix I-IV) The functionalities specified in appendix I-IV of ETS 300 125, part 2, is not used. ETSI ETSI TS 100 595 V7.0.0 (1999-08) 15 (GSM 08.56 version 7.0.0 Release 1998) Annex A (informative): Change Request History Change history SMG No. TDoc. No. CR. No. Section affected New version Subject/Comments SMG#08 4.0.2 ETSI Publication SMG#20 5.0.0 Release 1996 version SMG#27 6.0.0 Release 1997 version SMG#29 7.0.0 Release 1998 version ETSI ETSI TS 100 595 V7.0.0 (1999-08) 16 (GSM 08.56 version 7.0.0 Release 1998) History Document history V7.0.0 August 1999 Publication ISBN 2-7437-3370-5 Dépôt légal : Août 1999
858051528d06433dfa320aa65f167603
100 593
1 Introduction
858051528d06433dfa320aa65f167603
100 593
1.1 Scope
The use and general aspects of the A-bis interface are given in Technical Specification GSM 08.51. The present document gives the principle basis for the rest of the specifications specifying the interface between the Base Station Controller, BSC, and the Base Transceiver Station, BTS, with its transceivers, TRX. These components together form the Base Station System, BSS. (The interface between MSC and the BSS is specified in Technical Specifications GSM 08.01 - 08.20). The intention with this interface is to get a unified way of connecting remotely located BTSs/TRXs to a BSC allowing for the interconnection of BSCs and BTSs/TRXs from different manufacturers. In order to keep the BTS as simple as possible, BTS contains only those functions which have to recide close to the radio interface. ETSI ETSI TS 100 593 V7.0.0 (1999-08) 5 (GSM 08.52 version 7.0.0 Release 1998)
858051528d06433dfa320aa65f167603
100 593
1.2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present document. • References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. • For a specific reference, subsequent revisions do not apply. • For a non-specific reference, the latest version applies. • A non-specific reference to an ETS shall also be taken to refer to later versions published as an EN with the same number. • For this Release 1998 document, references to GSM documents are for Release 1998 versions (version 7.x.y). [1] GSM 01.04: "Digital cellular telecommunications system (Phase 2+); Abbreviations and acronyms". [2] GSM 08.01: "Digital cellular telecommunications system (Phase 2+); Base Station System - Mobile services Switching Centre (BSS - MSC) interface General aspects". [3] GSM 08.02: "Digital cellular telecommunications system (Phase 2+); Base Station System - Mobile-services Switching Centre (BSS - MSC) interface Interface principles". [4] GSM 08.04: "Digital cellular telecommunications system (Phase 2+); Base Station System - Mobile-services Switching Centre (BSS - MSC) interface Layer 1 specification". [5] GSM 08.06: "Digital cellular telecommunications system (Phase 2+); Signalling transport mechanism specification for the Base Station System - Mobile-services Switching Centre (BSS - MSC) interface". [6] GSM 08.08: "Digital cellular telecommunications system (Phase 2+); Mobile Switching Centre - Base Station System (MSC - BSS) interface Layer 3 specification". [7] GSM 08.20: "Digital cellular telecommunications system (Phase 2+); Rate adaption on the Base Station System - Mobile-services Switching Centre (BSS - MSC) interface". [8] GSM 08.51: "Digital cellular telecommunications system (Phase 2+); Base Station Controller - Base Transceiver Station (BSC - BTS) interface General aspects". [9] GSM 08.58: "Digital cellular telecommunications system (Phase 2+); Base Station Controller - Base Transceiver Station (BSC - BTS) interface Layer 3 specification". [10] GSM 08.60: "Digital cellular telecommunications system (Phase 2+); Inband control of remote transcoders and rate adaptors". [11] GSM 08.61: "Digital cellular telecommunications system (Phase 2+); Inband control of remote transcoders and rate adaptors (half rate)". [12] GSM 12.21: "Digital cellular telecommunications system (Phase 2+); Network Management (NM) procedures and message on the A-bis interface". ETSI ETSI TS 100 593 V7.0.0 (1999-08) 6 (GSM 08.52 version 7.0.0 Release 1998)
858051528d06433dfa320aa65f167603
100 593
2 Definitions and abbreviations
Abbreviations used in the present document are listed in GSM 01.04.
858051528d06433dfa320aa65f167603
100 593
2.1 Base Station System, BSS
The system of base station equipment (transceivers, controllers, etc..) which is viewed by the MSC through a single interface as defined by the GSM 08 0x series of recommendations, as being the entity responsible for communicating with Mobile Stations in a certain area. The radio equipment of a BSS may cover one or more cells. A BSS may consist of one or more base stations. If an internal interface according to the GSM 08.5x series at recommendations is implemented, then the BSS shall consist of one Base Station Controller (BSC) and several Base Transceiver Stations (BTSs). The functionality is described in Recommendation GSM 08.02.
858051528d06433dfa320aa65f167603
100 593
2.2 Base Station Controller, BSC
A network component in the PLMN with the functions for control of one or more Base Transceiver Stations (BTSs).
858051528d06433dfa320aa65f167603
100 593
2.3 Base Transceiver Station, BTS
A network component which serves one cell, and is controlled by a Base Station Controller. The BTS can consist of one or more TRXs with or without common control equipment.
858051528d06433dfa320aa65f167603
100 593
2.4 Cell
See GSM 03.02.
858051528d06433dfa320aa65f167603
100 593
2.5 Transceiver, TRX
The Transceiver, TRX, in the GSM PLMN is the functional entity which supports the 8 basic radio channels of the same TDMA-frame.
858051528d06433dfa320aa65f167603
100 593
2.6 Base Control Function, BCF
A functional entity which handles common control functions within a BTS, e.g. frequency hopping sequences etc. At a multi BTS site, one of the BCFs can also be choosen to perform functions common to the site (e.g. external alarms, power supply, time base). ETSI ETSI TS 100 593 V7.0.0 (1999-08) 7 (GSM 08.52 version 7.0.0 Release 1998)
858051528d06433dfa320aa65f167603
100 593
3 General
Technical Specifications GSM 08.01 - 08.20 specify the functional split and interface between MSC and the Base Station System, BSS, the A- interface. The BSS can be further subdivided into one BSC controlling one or more BTSs, each consisting of one or more TRXs. The interface treated by the present document is the interface between a BSC and a BTS. It is denoted the A-bis- interface. The A-bis-interface is capable of supporting three different internal BTS configurations: - one single TRX, - a collection of TRXs where all are served by a common physical connection, - a collection of TRXs, each served by its own physical connection. Figure 3.1 shows some possible configurations. BSS <-----------------------------------------> | +-----+ A-bis +-----+ | +--------•-------| TRX | BTS1 | | | + - - | | | | BCF | | | | +-----+ | | +-----+ | | | | TRX | | | A-bis + - - | | | +--------•-------| TRX | BTS2 | | + - - | | | | | TRX | | | + - - | | | | | BCF | | | +-----+ +-----+ A | | | +- - -+ | MSC +--------•-----------| BSC | A-bis |+---+| +-----+ | | +--------•--------|TRX| | | |+---+| | | | |+---+| | +--------•--------|TRX| | | | |+---+| BTS3 | | |+---+| | | +--------•--------|TRX| | | |+---+| | | | |+---+| | +--------•--------|BCF| | | | |+---+| +-----+ +-- - + Figure 3.1/08.52: BSS Subdivision and Interfaces The present document is based on the use of digital transmission system interfaces, either at 2048 kbit/s or at 64 kbit/s. Furthermore, the use of a subrate of 16 kbit/s and/or 8 kbit/s is supported for coded speech or rate adapted data. This interface will support the transcoder positioned either inside or outside BTS. In the latter case, remote control (synchronisation) of the transcoder is used. ETSI ETSI TS 100 593 V7.0.0 (1999-08) 8 (GSM 08.52 version 7.0.0 Release 1998)
858051528d06433dfa320aa65f167603
100 593
4 Functional division between BSC and BTS
858051528d06433dfa320aa65f167603
100 593
4.1 General
In Technical Specification GSM 08.02 the functional division between MSC and BSS is described. This section describes the further subdivision of functions between BSC and BTS/TRX required for the A-bis interface. A summary can be found in table 4.1. Some general requirements on the functionality of the A-bis interface are also specified.
858051528d06433dfa320aa65f167603
100 593
4.2 Terrestrial channel management
There is a unique mapping from traffic channels on the radio path to the terrestrial traffic channels. BSC makes the choice of radio channel and thereby also of the terrestrial channel for a call.
858051528d06433dfa320aa65f167603
100 593
4.3 Radio channel management
858051528d06433dfa320aa65f167603
100 593
4.3.1 Channel configuration management
The channel configuration is controlled between the BSC and OMC. Current configuration is downloaded from OMC to BSC which then controls the use of the radio channels (TDMA time slots for BCCH/CCCH, TCHs, SDCCHs etc).
858051528d06433dfa320aa65f167603
100 593
4.3.2 SDCCH (Stand alone DCCH) and TCH management
858051528d06433dfa320aa65f167603
100 593
4.3.2.1 Frequency hopping management
The hopping sequences for each BTS (cell) is downloaded from OMC to BSC. It is then the responsibility of BSC to download this information to each BTS and also to send the corresponding BCCH information to be transmitted in the BCCH time slots.
858051528d06433dfa320aa65f167603
100 593
4.3.2.2 Channel selection, link supervision and channel release
These functions are controlled by BSC. For channel selection BSC has to have information on blocked radio channels and also on interference level on idle channels. In the assignment messages to MS (Immediate Assign, Assign Command and Handover Command), a Starting Time parameter is included. This starting time is based on the frame number on the (new) BTS. Before sending the assign message to MS, BSC has to be informed on the current frame number in BTS. When assigning a channel, BSC shall inform BTS on relevant parameters, e.g. channel type, channel coding, rate adaption, starting time.
858051528d06433dfa320aa65f167603
100 593
4.3.2.3 Power control
The ordered MS power level is sent in the 16 bit L1-header of SACCH- blocks on the downlink and the actual power level used by MS is reported in the corresponding L1-header on the uplink. This header is inserted (downlink) and extracted (uplink) by BTS/TRX. The determination of required power level in MS is based on uplink radio measurements made by BTS/TRX and reported to BSC. The basic control of this power is performed by BSC and the dynamic regulation is performed by BSC or optionally by BTS. If BTS supports dynamic MS power regulation, BSC can indicate whether BTS is to regulate the MS power and if so, also the parameters required by BTS. The required TRX transmission power level on a channel is based on reported measurements performed by MS. The dynamic control of this power is optional. If supported, the basic control is performed by BSC and the dynamic regulation is performed by BSC or optionally by BTS. If BTS supports dynamic TRX transmission power regulation, BSC can indicate whether BTS is to regulate the transmission power and if so, also the parameters required by BTS. ETSI ETSI TS 100 593 V7.0.0 (1999-08) 9 (GSM 08.52 version 7.0.0 Release 1998)
858051528d06433dfa320aa65f167603
100 593
4.3.2.4 Idle channel observation
Idle channels are monitored by BTS.
858051528d06433dfa320aa65f167603
100 593
4.3.3 BCCH/CCCH management
TRX knows the timing of BCCH/CCCH slots (not known by BSC). The actual timing of BCCH/CCCH blocks therefore has to be made by BTS/TRX, including the scheduling of Paging Request messages on paging sub- channels. BCCH information is downloaded to BTS.
858051528d06433dfa320aa65f167603
100 593
4.3.4 Random access
Detection of a random access attempt has to be made by TRX which then sends a message to BSC containing the required timing advance, the frame number of the access attempt and the 8 bit Channel Request message sent by MS in the access burst. This information is then included by BSC in the following Immediate Assign message sent to MS.
858051528d06433dfa320aa65f167603
100 593
4.3.5 Channel coding/decoding
The error protection coding and decoding is made by BTS/TRX. Different coding and interleaving schemes are used for speech and data calls. This information has to be signalled from BSC to BTS on a per call basis.
858051528d06433dfa320aa65f167603
100 593
4.3.6 Transcoding/rate adaption
The A-bis interface has to allow for the transcoder/rate adaptor being positioned either inside or outside BTS.
858051528d06433dfa320aa65f167603
100 593
4.3.7 Timing advance
Timing advance has to be determined by TRX. When MS is on a dedicated channel (SDCCH, TCH), the required timing advance (TA) is sent to MS and the actual timing advance is reported by MS in the 16 bit L1-header of the SACCH blocks. At handover access, TA is determined by TRX and reported to MS in the PHYsical INFOrmation message sent by BTS/TRX. At random access, TA is determined by TRX but in those cases, TA has to be reported to BSC for inclusion in the IMMediate ASSIGN message sent to MS by BSC.
858051528d06433dfa320aa65f167603
100 593
4.3.8 Radio resource indication
BTS reports on status (interference level, blocking etc.) of idle channels to BSC on a regular basis.
858051528d06433dfa320aa65f167603
100 593
4.3.9 Measurements
MS measures the downlink received level and quality from the serving cell and the received level from surrounding cells. The results from these measurements are reported by MS in Measurement Report messages on SACCH. Uplink received level and quality are measured by BTS/TRX. The parameters for the uplink measurements are equivalent to the parameters used by MS for the corresponding downlink measurements (averaging period and dynamic range). The support of forwarding this basic raw measurement data over the A-bis interface is mandatory. Additionally, BTS and BSC may optionally support some pre-processing in BTS of this data. ETSI ETSI TS 100 593 V7.0.0 (1999-08) 10 (GSM 08.52 version 7.0.0 Release 1998)
858051528d06433dfa320aa65f167603
100 593
4.3.10 LAPDm functions (Layer 2)
Layer 2 on the radio interface (LAPDm) is terminated at BTS/TRX. Between BTS and BSC, LAPD is used.
858051528d06433dfa320aa65f167603
100 593
4.3.11 Paging
Paging is initiated by MSC via BSC. BSC determines the paging group to be used based on IMSI of the MS to be paged. The paging group value is sent to BTS together with the TMSI or IMSI. Based on the paging group information, BTS/TRX will build the relevant PAGING REQUEST message and execute the transmission of the message in the correct paging sub-channel.
858051528d06433dfa320aa65f167603
100 593
4.3.12 Handover
No handover recognition or decision is made by BTS. However, BTS/TRX has to detect the handover access made by a handed over MS. BTS/TRX also checks the Handover Reference value sent by MS in the handover access burst against the Handover Reference value received from BSC in the channel activation command. In case of an asynchronous handover, BTS/TRX then builds the PHYsical INFOrmation message (including the Timing Advance value) and sends it to MS. The handover access is also reported to BSC.
858051528d06433dfa320aa65f167603
100 593
4.3.13 Encryption
Encryption and decryption is made of the complete outgoing bit stream (except for preambles/synch words). This therefore has to be made by TRX. The encryption key has to be downloaded to BTS/TRX before encryption starts. Special control messages are therefore required between BSC and BTS/TRX.
858051528d06433dfa320aa65f167603
100 593
4.3.14 Mobility management and call control
All mobility management and call control functions recide in MSC. ETSI ETSI TS 100 593 V7.0.0 (1999-08) 11 (GSM 08.52 version 7.0.0 Release 1998) TABLE 4.1: Summary of functional division between BTS and BSC/MSC FUNCTION LOCATION BTS BSC/MSC TERRESTRIAL CHANNEL MANAGEMENT MSC-BSC channels Channel allocation...............................X Blocking indication..............................X BSC-BTS channels Channel allocation...............................X Blocking indication..................X RADIO CHANNEL MANAGEMENT Channel configuration management...................X Frequency Hopping Management.......................................X Execution............................X TCH management Channel allocation (choice)......................X Link supervision.................................X Channel release..................................X Idle channel observation.............X Power control determination..........X...........X Note 3 SDCCH management (Stand alone DCCH) SDCCH allocation.................................X Link supervision.................................X Channel release..................................X Power control determination..........X...........X Note 3 BCCH/CCCH management Scheduling of messages Management.....................................X Execution..........................X Random access Access detection...................X Immediate assign (access grant)................X Channel coding/decoding................X Transcoding/rate adaption..............X Note 1 Measurements Uplink measuring.....................X Note 2 Processing of reports from MS/TRX....X...........X Note 4 Traffic measurements.............................X ETSI ETSI TS 100 593 V7.0.0 (1999-08) 12 (GSM 08.52 version 7.0.0 Release 1998) TABLE 4.1. (continued): Summary of functional division between BTS and BSC/MSC BTS BSC/MSC Timing advance Calculation..........................X Signalling to MS at random access................X Signalling to MS at handover.........X Signalling to MS during call.........X Radio resource indication Report status of idle channels.......X LAPDm functions (Layer 2)..............X Encryption Management.......................................X Execution............................X (Key from BSC) Paging Initiation.......................................X DRX paging Management.....................................X Execution..........................X Handover BSC internal, one cell...........................X BSC internal, between cells......................X BSC external recognition, radio reason......................X recognition, traffic reason....................X decision.......................................X execution......................................X Handover access detection............X MOBILITY MANAGEMENT Authentication.....................................X Location updating..................................X CALL CONTROL.........................................X NOTE 1: Although the transcoder is always controlled by the BTS, it can optionally be located outside the BTS (e.g. at the BSC or at the MSC site). In that case, remote control is performed by BTS using inchannel signalling. NOTE 2: Including averaging comparable to what is done in the MS. NOTE 3: The support of power level determination in BTS is optional. NOTE 4: The support of forwarding all raw measurement data from MS/TRX over the A-bis interface and the processing of it in BSC is mandatory. The BTS/BSC may additionally support also some pre- processing in BTS of this raw data.
858051528d06433dfa320aa65f167603
100 593
5 Transcoding/rate adaption and multiplexing
The interface supports two options: transcoding/rate adaption performed in BTS or outside BTS.
858051528d06433dfa320aa65f167603
100 593
5.1 Transcoding/rate adaption in BTS
The transcoding of speech to normal 64 kbit/s A-law is performed within BTS. Data may be rate adapted or submultiplexed to 64 kbit/s circuits. ETSI ETSI TS 100 593 V7.0.0 (1999-08) 13 (GSM 08.52 version 7.0.0 Release 1998)
858051528d06433dfa320aa65f167603
100 593
5.2 Transcoding/rate adaption outside BTS
In this case the transcoder/rate adaptor is considered as part of the BSC. The channel coding/decoding is performed by BTS/TRX. The choice of coding/interleaving has to be signalled from BSC to BTS. The remote speech transcoder has to have knowledge of some radio parameters for an efficient decoding. In addition, the timing of the transcoder has to be aligned with the transmission of the frames over radio such that the frames from BSC arrive synchronized with the transmission over radio (minimizes delay due to remote transcoder). For this control and time alignment of the transcoder, inband signalling is used within a 16 kbit/s or an 8 kbit/s channel carrying speech or data, signalling and synchronisation. This remote control of the transcoder is specified in Technical Specifications GSM 08.60 (full rate traffic channels, 16 kbit/s submultiplexing only) and GSM 08.61 (half rate traffic channels, 16 or 8 kbit/s submultiplexing). For data, rate adaption to subrate 16 or 8 kbit/s is performed within BTS. For the link BTS-BSC, the following possibilities are foreseen: - rate adaption of 16 kbit/s or 8 kbit/s speech + control or 16 kbit/s data + control to 64 kbit/s (one radio traffic channel per 64 kbit/s terrestrial channel), - multiplexing of 16 kbit/s or 8 kbit/s speech + control or 16 kbit/s or 8 kbit/s data + control into one 64 kbit/s channel (up to eight radio traffic channels per 64 kbit/s terrestrial channel).
858051528d06433dfa320aa65f167603
100 593
6 Interface structures
858051528d06433dfa320aa65f167603
100 593
6.1 Communication channels
The A-bis interface is considered to have two types of communication channels (see figure 6.1): - traffic channel (SDC) at 8, 16 or 64 kbit/s carrying speech or data of one radio traffic channel (Bm or Lm channel), - signalling channels (SCH) at 16, 32 or 64 kbit/s, carrying signalling information (both BSC-MS and BSC-BTS signalling). B T S +-------------------+ ------------| SDCs | ------------| Speech and Data | ------------| 8, 16 or 64 kbit/s| B S C | | | | ------------| SCHs | ------------| Signalling | ------------|16, 32 or 64 kbit/s| +-------------------+ Figure 6.1/08.52: Communication Channel Types ETSI ETSI TS 100 593 V7.0.0 (1999-08) 14 (GSM 08.52 version 7.0.0 Release 1998)
858051528d06433dfa320aa65f167603
100 593
6.2 Signalling links
The addressing of TRXs and BCF is made using separate TEIs for each TRX and BCF. Three logical links are defined for each TEI: RSL: Radio Signalling Link used for supporting traffic management procedures (MS to network communication). One link per TRX. OML: Operations and Maintenance Link used for supporting network management procedures (transferring operations and maintenance messages). One link per TRX and BCF. L2ML: Layer 2 Management Link used for transferring layer 2 management messages to TRX or BCF. One link per TRX and BCF. A logical diagram for the architecture of the signalling links is given in figure 6.2/08.52. Only point to point signalling links are used. SMS messages are also carried on the signalling links. BSC BTS +-------------------+ +---------------------+ | +--------+ | | | | | | +-+ | | +-+ +-----+ | | | | | +-------- RSL --------------| +--| | | | | | | +-------- OML --------------| +--| TRX | TEI1 | | | | | +-------- L2ML--------------| +--| | | | | | +-+ | | +-+ + - - | | | | | | | | BCF | | | | | | | +-----+ | | | LAYER 2| +-+ | | +-+ +-----+ | | | | | +-------- RSL --------------| +--| | | | | | | +-------- OML --------------| +--| TRX | TEI2 | | | | | +-------- L2ML--------------| +--| | | | | | | | | | | | + - - | | | | | | | | | | | BCF | | | T E I | | | | | | | + - - + | | | | | | | | | | +-----+ | | | | | +-------- RSL --------------| +--| | | | | | | +-------- OML --------------| +--| TRX | TEI3 | | | | | +-------- L2ML--------------| +--| | | | | | | | | | | | + - - | | | | | | | | | | | BCF | | | MANAGE-| | | | | | | + - - + | | | MENT | +-+ | | +-+ | | | | +-+ | | +-+ +-----+ | | | | | + - - - - OML - - - - - - | + -| BCF | TEI4 | | | | | + - - - - L2ML - - - - - - | + -| | | | | | +-+ | | +-+ +-----+ | | | | ... | | ... ....... | | | | . ............................. .... BCF . | | | | ... | | ... ....... | | +--------+ | | | +-------------------+ +---------------------+ Figure 6.2/08.52: Logical L2 links of A-bis interface ETSI ETSI TS 100 593 V7.0.0 (1999-08) 15 (GSM 08.52 version 7.0.0 Release 1998)
858051528d06433dfa320aa65f167603
100 593
6.3 Signalling model
A signalling model for the A-bis interface and its signalling environment can be found in figure 6.3. CM and MM messages are not interpreted by BSC or BTS. Over the A interface they are tranferred using DTAP (Direct Transfer Application Part) and over the A-bis interface they are transferred as transparent messages. RR messages are mapped to BSSAP (BSS Application Part) in BSC. In BTS, most of them are handled as transparent messages. However, some of them have to be interpreted by BTS (e.g. random access, start ciphering, paging). The BTSM (BTS Management) entities contain procedures for handling these messages and also other procedures for managing the BTS as defined in Technical Specification GSM 08.58. In BTS there is a mapping between BTSM and the relevant RR messages over the radio interface (RR'). The Layer 2 protocol over the A-bis interface is based on LAPD. L2 addressing is made to TRX (or BCF) using the TEI of LAPD. Different L2 links are used for traffic management messages (RSL, Radio Signalling Link), network management messages (OML, Operation & Maintenance Link) and L2 management messages (L2ML, Layer 2 Management Link). A model of Layer 3 for the A-bis interface can be found in figure 6.4. For traffic management, two types of signalling messages have been defined: Transparent Messages:Messages which are forwarded by BTS without interpretation or changes. Non-Transparent Messages:Messages which are sent only between BSC and BTS and which BTS is acting upon or which are the results of BTS actions. In addition, the messages have been grouped into four main groups: Radio Link Layer Management, Dedicated Channel Management, Common Channel Management and TRX Management messages. Discrimination between these types and groups is based on the Message Discriminator which is sent as the first octet in all messages. Transparent and non-transparent messages are discriminated by a transparancy flag (T-bit) in the Message Discriminator. Transparent messages are merely forwarded to L2 on the radio interface. In order to address the relevant radio channel, a Channel Number element is included to support the distribution of messages to relevant physical channels on the TRX. A Link Identifier element supports the distribution on logical links/channels on the radio interface (compare the DLCI element of the A interface, GSM 08.06). ETSI ETSI TS 100 593 V7.0.0 (1999-08) 16 (GSM 08.52 version 7.0.0 Release 1998) ETSI ETSI TS 100 593 V7.0.0 (1999-08) 17 (GSM 08.52 version 7.0.0 Release 1998) Chan No Link distri- bution Other processes within BTS Traffic Management Procedures (08.58) Transparent Messages Non- Transparent Messages Distribution Network Management Procedures (12.21) L2 Management Procedures To radio interface 0 62 63 RSL OML L2ML L3 L2 Figure 6.4/08.52: L3 model ETSI ETSI TS 100 593 V7.0.0 (1999-08) 18 (GSM 08.52 version 7.0.0 Release 1998) Annex A (informative): Change Request History Change history SMG No. TDoc. No. CR. No. Section affected New version Subject/Comments SMG#07 4.0.4 ETSI Publication SMG#13 4.1.0 ETSI Publication SMG#15 4.2.0 ETSI Publication SMG#20 5.0.0 Release 1996 version SMG#27 6.0.0 Release 1997 version SMG#29 7.0.0 Release 1998 version ETSI ETSI TS 100 593 V7.0.0 (1999-08) 19 (GSM 08.52 version 7.0.0 Release 1998) History Document history V7.0.0 August 1999 Publication ISBN 2-7437-3366-7 Dépôt légal : Août 1999
52a095daef2821950f03b36be5124217
100 592
1 General
52a095daef2821950f03b36be5124217
100 592
1.1 Scope
The present document is an introduction to the 08.5X - 08.6X series of GSM Technical Specifications and deals with the definition of the base station controller (BSC) to base transceiver station (BTS) interface defined inside the base station system (BSS) for the GSM system. These Technical Specifications define the basic interface with some identified options requiring further elaboration. The BSC-BTS interface is mandatory within GSM only if the BSC and the BTS are not colocated. ETSI ETSI TS 100 592 V7.0.0 (1999-08) 5 (GSM 08.51 version 7.0.0 Release 1998)
52a095daef2821950f03b36be5124217
100 592
1.2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present document. • References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. • For a specific reference, subsequent revisions do not apply. • For a non-specific reference, the latest version applies. • A non-specific reference to an ETS shall also be taken to refer to later versions published as an EN with the same number. • For this Release 1998 document, references to GSM documents are for Release 1998 versions (version 7.x.y). [1] GSM 01.04: "Digital cellular telecommunications system (Phase 2+); Abbreviations and acronyms". [2] GSM 03.50: "Digital cellular telecommunications system (Phase 2+); Transmission planning aspects of the speech service in the GSM Public Land Mobile Network (PLMN) system". [3] GSM 08.08: "Digital cellular telecommunications system (Phase 2+); Mobile Switching Centre - Base Station System (MSC - BSS) interface Layer 3 specification". [4] GSM 08.51: "Digital cellular telecommunications system (Phase 2+); Base Station Controller - Base Transceiver Station (BSC - BTS) interface General aspects". [5] GSM 08.52: "Digital cellular telecommunications system (Phase 2+); Base Station Controller - Base Transceiver Station (BSC - BTS) interface Interface principles". [6] GSM 08.54: "Digital cellular telecommunications system (Phase 2+); Base Station Controller - Base Transceiver Station (BSC - BTS) interface Layer 1 structure of physical circuits". [7] GSM 08.56: "Digital cellular telecommunications system (Phase 2+); Base Station Controller - Base Transceiver Station (BSC - BTS) interface Layer 2 specification". [8] GSM 08.58: "Digital cellular telecommunications system (Phase 2+); Base Station Controller - Base Transceiver Station (BSC - BTS) interface Layer 3 specification". [9] GSM 08.60: "Digital cellular telecommunications system (Phase 2+); Inband control of remote transcoders and rate adaptors". [10] GSM 08.61: "Digital cellular telecommunications system (Phase 2+); Inband control of remote transcoders and rate adaptors (half rate)". [11] GSM 12.00: "Digital cellular telecommunications system (Phase 2+); Objectives and structure of Network Management (NM)". [12] GSM 12.01: "Digital cellular telecommunications system (Phase 2+); Common aspects of GSM Network Management (NM)". [13] GSM 12.07: "Digital cellular telecommunications system (Phase 2+); Operations and performance management". [14] GSM 12.02: "Digital cellular telecommunications system (Phase 2+); Subscriber, Mobile Equipment (ME) and services data administration". [15] GSM 12.03: "Digital cellular telecommunications system (Phase 2+); Security management". [16] GSM 12.04: "Digital cellular telecommunications system (Phase 2+); Performance data measurements". ETSI ETSI TS 100 592 V7.0.0 (1999-08) 6 (GSM 08.51 version 7.0.0 Release 1998) [17] GSM 12.05: "Digital cellular telecommunications system (Phase 2+); Subscriber related event and call data". [18] GSM 12.06: "Digital cellular telecommunications system (Phase 2+); GSM Network change control". [19] GSM 12.10: "Digital cellular telecommunications system (Phase 2+); Maintenance provisions for operational integrity of Mobile Stations (MS)". [20] GSM 12.11 "Digital cellular telecommunications system (Phase 2+); Maintenance of the Base Station System (BSS)". [21] GSM 12.13: "Digital cellular telecommunications system (Phase 2+); Maintenance of the Mobile- services Switching Centre (MSC)". [22] GSM 12.14: "Digital cellular telecommunications system (Phase 2+); Maintenance of location registers". [23] GSM 12.20: "Digital cellular telecommunications system (Phase 2+); Network Management (NM) procedures and messages". [24] GSM 12.21: "Digital cellular telecommunications system (Phase 2+); Network Management (NM) procedures and message on the A-bis interface". [25] GSM 12.22: "Digital cellular telecommunications system (Phase 2+); Interworking of GSM Network Management (NM) procedures and messages at the Base Station Controller (BSC)". [26] CCITT Recommendation Q.920: "ISDN user-network interface data link layer - General aspects". [27] CCITT Recommendation Q.921: "ISDN user-network interface - Data link layer specification".
52a095daef2821950f03b36be5124217
100 592
1.3 Definitions and abbreviations
Abbreviations used in the present document are listed in GSM 01.04.
52a095daef2821950f03b36be5124217
100 592
2 Interface capabilities
The BSC-BTS interface shall be capable of supporting all the services offered to the GSM users and subscribers. In addition it shall also allow control of the radio equipment and radio frequency allocation in the BTS.
52a095daef2821950f03b36be5124217
100 592
3 Interface specification objectives
The BSC to BTS interface specifications should allow the following: (I) Connection of various manufacturers BTS/TRX to the same BSC, according to the location of the transcoder. (II) The use of several manufacturers BSC to the same type of BTS/TRX, according to the location of the transcoder. (III) The use of the same BTS/TRX in any PLMN, according to the location of the transcoder. (IV) The use of the same BSC in any PLMN. (V) Separate evolution of BSC and BTS/TRX technology. (VI) Separate evolution of O & M facilities. (VII) Sub-multiplexing of speech channels on a 64 kbit circuit. (VIII) Evolution towards lower speech coding rates. (IX) Location of transcoders either in BSC or in BTS. (X) Support of all services defined in the 02 series of GSM Technical Specifications. (XI) A stepwise expansion of capacity in a BTS. (XII) Different physical solution of the various equipment in the BTS. (XIII) Support of a single TRX forming a BTS. ETSI ETSI TS 100 592 V7.0.0 (1999-08) 7 (GSM 08.51 version 7.0.0 Release 1998) (XIV) Support of a set of TRX'S forming a BTS. (XV) Support of a BTS as one entity.
52a095daef2821950f03b36be5124217
100 592
4 Interface characteristics
The interface is defined to be at the terrestrial link of a remote BTS connected to the BSC. The BSC to BTS interface is specified by a set of characteristics, including: a) physical and electrical parameters; b) channel structures; c) signalling transfer procedures; d) configuration and control procedures; e) operation and maintenance information support. The definition of the BSC to BTS/TRX interface follows a layered approach similar to the ISDN. Layer 3 is for the most part based on Technical Specification GSM 08.08 with additional procedures for control of radio resources. Layer 2 is based on the LAPD protocol. Layer 1 is either digital (at a rate 2048 kbit/sec with a frame structure of 32 x 64 kbit/sec time slots or at a rate of 64 kbit/sec.) or analogue with the data being passed by the use of modems (this latter case is a national option). In the case that the transcoder is positioned outside the BTS, the overall one way propagation delay between the Point Of Interconnection to PSTN/ISDN and the MS is limited to 1.5 ms (approximately 300 km). With the transcoder in the BTS, the limit is 6.5 ms (approximately 1300 km). These limits may be subject to increase resulting from savings made in the overall network. See also Technical Specification GSM 03.50. 5 Other technical specifications on the BSC-BTS interface The full structure of the Technical Specifications specifying the BSC to BTS interface are as follows: 5.1 Technical Specification GSM 08.52 BSC-BTS Interface Principles This specification gives the principle basis for the rest of the specifications specifying the interface between the base station controller and the base transceiver station. It gives the functional split between these two entities. 5.2 Technical Specification GSM 08.54 BSC-BTS Layer 1 Specification This specification defines the structure of the physical layer at the BSC - BTS interface. The physical interface is either chosen as 2048 kbit/sec or as 64 kbit/sec, both according to standard CCITT recommendations. Depending on location of transcoders, speech is standard A-law or it is 16 kbit/sec remote control protocol multiplexed or rate adapted to 64 kbit/sec in the same way as data. ETSI ETSI TS 100 592 V7.0.0 (1999-08) 8 (GSM 08.51 version 7.0.0 Release 1998) 5.3 Technical Specification GSM 08.56 BSC-BTS Layer 2 Specification At layer 2 the signalling information is passed by a standard LAPD protocol mechanism in accordance with the CCITT Recommendations Q.920 and Q.921. 5.4 Technical Specification GSM 08.58 BSC-BTS Layer 3 Specification This specification specifies the layer 3 procedures used on the BSC-BTS interface for control of the GSM services. The functional split between BSC and BTS is defined in Technical Specification GSM 08.52. 5.5 Technical Specification GSM 12.21 BSC-BTS Operation/Maintenance Signalling This specification defines the transport mechanism for O&M messages over the Abis interface. O&M procedures and messages are defined in GSM 12 series. 5.6 Technical Specification GSM 08.60 Inband Control of Remote Transcoders and Rate Adaptors The transcoder is a part of the BSS and may optionally be located outside the BTS (e.g. at MSC-site or at BSC-site) in order to make it possible to multiplex speech and data channels on the links within the BSS and on the BSC-BTS link. This specification describes the protocol which carries the full rate speech and data frames between the transcoder and the radio link codec across a 16 kbit/sec interface. Both full rate speech and full rate data services are covered. It also defines the signals needed for remote controlling the timing of the transcoder in accordance to the transmission time at the radio link. It also addresses the signals for voice activity and comfort noise. It interfaces the 06- series to the 05- series. 5.7 Technical Specification GSM 08.61 Inband Control of Remote Transcoders and Rate Adaptors for Half Rate Traffic Channels This Technical Specification describes the protocol which carries the half rate speech and data frames between the transcoder and the radio link codec across a 16 kbit/sec or an 8 kbit/sec interface. Both half rate speech and half rate data services are covered. It also defines the signals needed for remote controlling the timing of the transcoder in accordance to the transmission time at the radio link. It also addresses the signals for voice activity and comfort noise. ETSI ETSI TS 100 592 V7.0.0 (1999-08) 9 (GSM 08.51 version 7.0.0 Release 1998) Annex A (informative): Change Request History Change history SMG No. TDoc. No. CR. No. Section affected New version Subject/Comments SMG#07 4.0.4 ETSI Publication SMG#13 003 4.1.0 8 kbit/s submultiplexing SMG#20 5.0.0 Release 1996 version SMG#27 6.0.0 Release 1997 version SMG#29 7.0.0 Release 1998 version ETSI ETSI TS 100 592 V7.0.0 (1999-08) 10 (GSM 08.51 version 7.0.0 Release 1998) History Document history V7.0.0 August 1999 Publication ISBN 2-7437-3364-0 Dépôt légal : Août 1999
1352d9d2d97b335ddb6d861824150a6f
100 591
1 Scope
....................................................................................................................................................... 6
1352d9d2d97b335ddb6d861824150a6f
100 591
2 References, abbreviations and definitions
............................................................................................... 6
1352d9d2d97b335ddb6d861824150a6f
100 591
2.1 References
................................................................................................................................................................6
1352d9d2d97b335ddb6d861824150a6f
100 591
2.2 Abbreviations
...........................................................................................................................................................7
1352d9d2d97b335ddb6d861824150a6f
100 591
2.3 Definitions
................................................................................................................................................................7