hash
stringlengths 32
32
| doc_id
stringlengths 7
13
| section
stringlengths 3
121
| content
stringlengths 0
3.82M
|
|---|---|---|---|
6ce15bf95a1b22a297ad4f2826214f21
|
100 594
|
3 Abbreviations
|
Abbreviations used in the present document are listed in GSM 01.04
|
6ce15bf95a1b22a297ad4f2826214f21
|
100 594
|
4 Layer 1 specification
|
All the CCITT recommendations referred to are Blue Book. Layer 1 shall utilize digital transmission at a rate of 2 048 kbit/sec with a frame structure of 32 * 64 kbit/sec time slots, as specified in CCITT Recommendation G.705 section 3 or at a rate of 64 kbit/sec. The physical/electrical characteristics are defined in CCITT Recommendation G.703. Synchronization at the BTS/TRX for the transmitted bit stream toward the BSC shall be derived from the received bit stream from the BSC. For transmission rate at 64 kbit/sec it shall be an interface as defined in CCITT Recommendation G.703. For transmission rate at 2048 kbit/sec the functional characteristics are defined in CCITT Recommendation G.732 section 2 and 3, and fault conditions should be treated in accordance with CCITT Recommendation G.732 section 4. The idle pattern must be transmitted on every timeslot that is not assigned to a channel, and to every timeslot of a channel that is not allocated to a call. The idle pattern shall be 01010100 for a 64 kbit/sec channel and the 2-bit pattern 01 for 16 kbit/sec channels. For 8 kbit/s channels, the idle pattern shall be consecutive ones or zeros according to the corresponding idle pattern bit of a 16 kbit/s channel. If transcoders are located in BTS speech encoding shall be the A-law as defined in CCITT Recommendation G.711. If speech transcoders are located in the BSC the speech, data and signalling channels will utilize transmission rates of 8 kbit/sec, 16 kbit/sec or 64 kbit/sec according to Technical Specifications GSM 08.60 and GSM 08.61. They shall be rate adapted or multiplexed according to CCITT Recommendation I.460 with fixed format, to fit into the physical interface. Data encoding is covered in Technical Specification GSM 08.20. In the case of a 2 048 kbit/sec circuit, multidrop solutions should be possible. Dynamic sharing of terrestrial 64 kbit/sec channels between BTS:s on a per-call basis must not be used. ETSI ETSI TS 100 594 V7.0.0 (1999-08) 7 (GSM 08.54 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#16 5.0.0 Phase 2+ version SMG#27 6.0.0 Release 1997 version SMG#29 7.0.0 Release 1998 version ETSI ETSI TS 100 594 V7.0.0 (1999-08) 8 (GSM 08.54 version 7.0.0 Release 1998) History Document history V7.0.0 August 1999 Publication ISBN 2-7437-3368-3 Dépôt légal : Août 1999
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
1 Scope
|
The use and general aspects of the Base Station Controller (BSC) to Base Station Transceiver (BTS) interface (the A-bis interface) are given in GSM 08.51. The present document specifies the general structure of layer 3 and traffic management procedures and messages used on the A-bis interface to support signalling procedures as defined in GSM 04.08. Support for Location Services (LCS) related signalling, as defined in GSM 03.71, is also included. GSM 03.71 identifies new A-bis signalling to support BTS-embedded Type B LMUs as well as standalone, Type B LMUs. The standalone Type B LMU supports the layer 1 and 2 signalling for the A-bis as well as the Location Service message defined in this specification. Network management procedures and messages for the A-bis interface are defined in GSM 08.59. The functional split between BSC and BTS is defined in GSM 08.52. The procedures and messages required to support this split are defined in detail in this TS.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
1.1 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 03.20: "Digital cellular telecommunications system (Phase 2+); Security related network functions". [2a] GSM 03.71: "Digital cellular telecommunications system (Phase 2+); Location Services (LCS); (Functional description) - Stage 2". [3] GSM 04.04: "Digital cellular telecommunications system (Phase 2+); Layer 1; General requirements". [4] GSM 04.05: "Digital cellular telecommunications system (Phase 2+); Data Link (DL) layer; General aspects". [5] GSM 04.06: "Digital cellular telecommunications system (Phase 2+); Mobile Station - Base Station System (MS - BSS) interface; Data Link (DL) layer specification". [6] GSM 04.08: "Digital cellular telecommunications system (Phase 2+); Mobile radio interface layer 3 specification". [7] GSM 04.12: "Digital cellular telecommunications system (Phase 2+); Short Message Service Cell Broadcast (SMSCB) support on the mobile radio interface". [7a] GSM 04.71: "Digital cellular telecommunications system (Phase 2+); Mobile radio interface layer 3 Location Services (LCS) specification". [8] GSM 05.02: "Digital cellular telecommunications system (Phase 2+); Multiplexing and multiple access on the radio path". ETSI ETSI TS 100 596 V7.4.1 (2000-05) 9 (GSM 08.58 version 7.4.1 Release 1998) [9] GSM 05.05: "Digital cellular telecommunications system (Phase 2+); Radio transmission and reception". [10] GSM 05.08: "Digital cellular telecommunications system (Phase 2+); Radio subsystem link control". [11] GSM 05.09: "Digital cellular telecommunications system (Phase 2+); Link Adaptation". [12] GSM 05.10: "Digital cellular telecommunications system (Phase 2+); Radio subsystem synchronization". [13] 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". [14] GSM 08.08: "Digital cellular telecommunications system (Phase 2+); Mobile-services Switching Centre - Base Station System (MSC - BSS) interface; Layer 3 specification". [15] GSM 08.51: "Digital cellular telecommunications system (Phase 2+); Base Station Controller - Base Transceiver Station (BSC - BTS) interface; General aspects". [16] GSM 08.52: "Digital cellular telecommunications system (Phase 2+); Base Station Controller - Base Transceiver Station (BSC - BTS) interface; Interface principles". [17] GSM 08.56: "Digital cellular telecommunications system (Phase 2+); Base Station Controller - Base Transceiver Station (BSC - BTS) interface; Layer 2 specification".
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
1.2 Abbreviations
|
Abbreviations used in the present document are listed in GSM 01.04.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
2 Protocol model
|
A model for L3 can be found in figure 2.1. 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). 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 transparency 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). All messages in this GTS are to be transmitted on the A-bis interface using the I format of LAPD, except for MEASUREMENT RESULT which is sent in UI format. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 10 (GSM 08.58 version 7.4.1 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 2.1/08.58: L3 model
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
3 Radio Link Layer Management Procedures
|
This clause describes procedures related to the management of a link layer connection on the radio path.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
3.1 Link establishment indication
|
This procedure is used by BTS to indicate to BSC that a layer 2 link on the radio path has been established in multi- frame mode at the initiative of an MS. BSC can use this indication to set up an SCCP connection to MSC. Upon reception of a SABM frame on a link on an active channel, the BTS sends an ESTablish INDication message to BSC. The message contains the contents of the information field of the SABM frame if present. The procedure is used in all establishment cases, for all channels and all SAPIs. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 11 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
3.2 Link establishment request
|
This procedure is used by BSC to request the establishment of a link layer connection in multi-frame mode on the radio path. The procedure is started by BSC sending an ESTablish REQuest message to BTS. BTS then establishes the link by sending an SABM frame. Upon reception of the acknowledgement (UA-frame) from MS, BTS sends an ESTablish CONFirm message to BSC. In case of a failure, BTS sends a RELease INDication and an ERRor INDication message to BSC (cf. GSM 04.06).
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
3.3 Link release indication
|
This procedure is used by BTS to indicate to BSC that a link layer connection on the radio path has been released at the initiative of an MS. When receiving a DISC frame on a link layer connection in multi-frame mode, BTS sends a RELease INDication message to BSC. (If the link layer is in idle mode, BTS will send a DM frame to MS but does not notify BSC.) Collision cases are treated as specified in GSM 04.06.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
3.4 Link release request
|
This procedure is used by BSC to request the release of a link layer connection on the radio path. The procedure is started by BSC sending a RELease REQuest message to BTS. BTS then sends a DISC frame to MS. When it has received the acknowledgement (UA or DM frame), BTS sends a RELease CONFirm message to BSC. Collision cases are treated as specified in GSM 04.06. If BTS has repeated the DISC frame N200 times, BTS sends a RELease INDication and an ERRor INDication message to BSC (cf. GSM 04.06). ETSI ETSI TS 100 596 V7.4.1 (2000-05) 12 (GSM 08.58 version 7.4.1 Release 1998) 3.5 Transmission of a transparent L3-Message in acknowledged mode This procedure is used by BSC to request the sending of a L3 message to MS in acknowledged mode. BSC sends a DATA REQuest message to BTS. The message contains the complete L3 message to be sent in acknowledged mode. 3.6 Reception of a transparent L3-Message in acknowledged mode This procedure is used by BTS to indicate the reception of a L3 message in acknowledged mode. BTS sends a DATA INDication message to BSC. The message contains the received L3 message. 3.7 Transmission of a transparent L3-Message in unacknowledged mode This procedure is used by BSC to request the sending of a L3 message to MS in unacknowledged mode. BSC sends a UNIT DATA REQuest message to BTS. The message contains the L3 message to be sent to MS in unacknowledged mode. 3.8 Reception of a transparent L3-Message in unacknowledged mode This procedure is used by BTS to indicate the reception of a L3 message in unacknowledged mode. BTS sends a UNIT DATA INDication message to BSC. The message contains the received L3 message. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 13 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
3.9 Link error indication
|
This procedure is used by BTS to indicate an abnormal case such as the following. - a protocol error as specified in GSM 04.06, subclauses 5.6.4, 5.7.3 and annex G; - a link layer failure, i.e. the repetition of an I-frame N200 times without an acknowledgement; - the repetition of an SABM or DISC frame N200 times without an acknowledgement; - the reception of an SABM frame in multi-frame established state. When such an event has occurred, BTS notifies BSC by sending an ERROR INDication message containing the relevant cause information.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4 Dedicated channel management procedures
| |
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.1 Channel activation
|
This procedure is used to activate a channel at the BTS for an MS which later will be commanded to this channel by an IMMediate ASSIGN, an ASSIGN CoMmanD, an ADDitional ASSIGNment; a NOTIFICATION, a CHANNEL RELEASE (with a Channel description) a HANDOver CoMmanD or a CONFiguration CHange CoMmanD message. In the handover case, the procedure is used between the target BSC and the target BTS to activate a channel for a subsequent handover from the old BTS.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.1.1 Signalling Procedure
|
BSC determines what channel shall be used and starts up that channel at BTS by sending a CHANnel ACTIVation message to the relevant TRX. This message contains the reason for the activation (immediate assignment, assignment, asynchronous/synchronous handover, additional assignment, activation of a secondary channel in a multislot configuration), the identification of the channel to be used (channel no) and a complete description of the channel (full/half rate, speech/data, coding/rate adaption, hopping sequence, encryption key etc.). If the Encryption Information field is present, the activation is done with ciphering active. If the Encryption Information element is not present, activation is done without ciphering. After activating the channel as requested, TRX responds with the CHANnel ACTIVation ACKnowledge message. This message contains the current frame number at BTS. The frame number is used by BSC to determine the Starting Time parameter to be included in the following assignment message to MS. (A suitable number has to be added to current frame number to take all possible signalling delays into account). ETSI ETSI TS 100 596 V7.4.1 (2000-05) 14 (GSM 08.58 version 7.4.1 Release 1998) If the TRX for some reason cannot activate the resource as requested by the CHANnel Activation message, the TRX shall return a CHANnel ACTIVation Negative ACKnowledge message with the most appropriate cause value. Possible cause values may be: - O&M intervention (e.g. channel blocked); - resource not available (e.g. speech coder, encryption device); - equipment failure; - channel already activated; - etc. In the handover case, the procedure is initiated by the target BSC when this receives the HANDOver REQuest message from MSC (or autonomously by BSC for BSC internal handover). The BSC sends a CHANnel ACTIVation message to the relevant TRX. The message contains the Handover Reference value which can be used by the BTS to check the Handover Access from MS. After activation of the channel TRX responds with a CHANnel ACTIVation ACKnowledge message containing the current frame number at BTS. The BSC can then determine the Starting Time parameter to be included in the HANDOver REQuest ACKnowledge message to MSC (and the HANDOver CoMmanD message to MS).
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.1.2 Activation for Intra-Cell Channel Change
|
This activation precedes the Immediate Assignment, Assignment or Additional assignment procedures. The Timing Advance element must be included in the CHANNEL ACTIVATION message. BTS activates the channel and starts transmission and reception on the main channel in the indicated mode. Ciphering is started if so indicated in the encryption information. The reception and transmission on SACCH is also started immediately. If the BS and/or MS power elements and/or the Physical Context element are present, the reception and transmission processes and the L1-header of SACCH are initialized accordingly. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 15 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.1.3 Activation for Asynchronous Handover
|
BTS starts transmission immediately on the main channel in the indicated mode and with encryption if so indicated. If the MS Power element is present the BTS may start transmission also on the SACCH. When receiving a correct access burst with the correct handover reference, BTS starts the normal reception process on the main channel in the indicated mode and starts receiving (and sending if not started earlier) on SACCH. Deciphering is started if so indicated. The handover detection procedure towards BSC is also started.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.1.4 Activation for Synchronous Handover
|
BTS starts transmission immediately on the main channel in the indicated mode and with encryption if so indicated. If the MS Power and Timing Advance element are present, BTS shall start transmission also on SACCH with the timing advance and MS power control parameters indicated. If only the MS power element is present the BTS may start transmission also on the SACCH. When receiving a correct access burst with the correct handover reference, BTS starts the normal reception process on the main channel in the indicated mode, with deciphering applied if so indicated, and starts receiving (and sending if not started earlier) on SACCH. The handover detection procedure towards BSC is also started. Alternatively, the reception of a correctly decoded frame from the MS on the main channel, in the indicated mode and deciphering applied if so indicated, allows the start of sending on SACCH (if not already started) and starts the handover detection procedure towards the BSC. NOTE: The activation for synchronous handover can be used for pseudo synchronized handover.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.1.5 Activation for Secondary Channels in Multislot Configuration
|
BTS activates the channel and starts transmission and reception on the traffic and SACCH channels in the indicated mode. Ciphering is applied if so indicated in the encryption information. If the BS and/or MS power elements and/or the Physical Context element are present, the reception if applicable and transmission processes and the L1-header of SACCH are initialized accordingly.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.1.6 Channel reactivation
|
This procedure is used by BSC to request a reactivation of an active channel. During the reactivation, information flows, e.g., user information such as speech or data, that are common for the two phases of operation, are not interrupted. BSC initiates the procedure by sending a CHANNEL ACTivation message to BTS where the activation type indicates "reactivation", the BTS shall reactivate the channel with the new parameters. After having successfully reactivate the channel with the parameters supplied the BTS responds with a CHANNEL ACTivation ACKnowledge message to BSC. If the TRX for some reason cannot reactivate the channel as requested in the CHANNEL ACTIVATION message, the TRX shall return a CHANNEL ACTivation Negative ACKnowledge message with the most appropriate cause value. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 16 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.2 Channel MODE MODIFY
|
This procedure is used by BSC to request a change of the channel mode and/or a change between uni-directional and bi- directional channel types of an active channel. In addition, for secondary channels in a multislot configuration, the procedure can be used by BSC to request a change in the encryption information of an active channel. BSC initiates the procedure by sending a MODE MODIFY message to BTS. The message contains the new mode to be used. After having changed to the new mode, BTS responds with a MODE MODIFY ACKnowledge message to BSC. If the TRX for some reason cannot modify the channel as requested in the MODE MODIFY message, the TRX shall return a MODE MODIFY Negative ACKnowledge message with the most appropriate cause value.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.3 Handover detection
|
This procedure is used between the target BTS and BSC when a handed over MS accesses the new BTS. The procedure is initiated by BTS upon detection of an MS on a channel activated for handover as described in subclause 4.1.3 for the asynchronous handover and in subclause 4.1.4 for synchronous handover. In case of an asynchronous handover, BTS builds the PHYsical INFOrmation message as specified in GSM 04.08, sends the message to MS in unacknowledged mode on the main signalling link and starts timer T3105. A HANDOver DETection message is sent to BSC. This message contains the measured delay of the access burst. If the timer expires before the reception of a correctly decoded frame from MS, BTS repeats the PHYSical INFOrmation message to MS as specified in GSM 04.08. If the PHYsical INFOrmation message has been repeated Ny1 times without a correctly decoded frame being received from MS, the BTS shall send a CONNECTION FAILURE message to BSC with the cause value "handover access failure". In case of a synchronous handover, BTS only sends a HANDOver DETection message to BSC (no PHYsical INFOrmation message sent to MS). If the handover detection is based on the detection of an handover access burst with the correct handover reference, see subclause 4.1.4, the measured delay of the access burst is included in the HANDOver DETection message.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.4 Start of encryption
|
This procedure is used to start encryption according to the procedure defined in GSM 04.08. The procedure is initiated by BSC upon reception of the CIPHER MODE COMMAND message from MSC (see GSM 08.08). ETSI ETSI TS 100 596 V7.4.1 (2000-05) 17 (GSM 08.58 version 7.4.1 Release 1998) BSC sends the ENCRyption CoMmanD message to the relevant TRX and channel. In case of a Multislot configuration the message is sent only to the TCH used as a main channel (defined in GSM 05.02). The message contains all information required to select and load the user data and encryption device with the appropriate key and also the complete Ciphering Mode Command message to be sent to MS. After receipt of this message, TRX sends the CIPHering MODe CoMmanD message to MS in unciphered form and starts deciphering as described in GSM 04.08 and GSM 03.20. The start of deciphering and the sending of the Ciphering Mode Command message to MS must be done simultaneously. When receiving the CIPHering MODe CoMmanD, MS starts both deciphering and enciphering and sends the CIPHering MODe COMplete message. TRX starts enciphering upon reception of any correct layer 2 frame which is received after start of deciphering. If the TRX for some reason can not perform the enciphering as requested in the ENCRYPTION COMMAND, the TRX shall return an ERROR REPORT message, e.g., with the cause "Encryption algorithm not implemented".
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.5 Measurement reporting
|
These procedures are used to report to BSC all parameters and measurement results required by BSC for handover requirement determination. One procedure is also used to report to the BSC extended measurements made by Mobile Stations. MS measures downlink received signal level and quality from the serving cell and received signal level from surrounding cells as defined in GSM 05.05 and GSM 05.08. The measurement results are reported in Measurement Report messages sent in every SACCH block (every 480 ms) or, in case SACCH is used also for other signalling, in at least every second SACCH block (every 960 ms). The TRX measures the received signal level and the quality on the uplink of the current channel. The averaging period is one SACCH block period (same as the basic period for MS). These measurements made by MS and TRX form the basic raw data for the handover algorithms in BSC/MSC. The support of forwarding this raw data over the A-bis interface is mandatory for both BTS and BSC. The procedure to be used for this basic measurement reporting is defined in subclause 4.5.1. In addition, the BTS and BSC may optionally support some pre-processing in BTS of these basic measurements. The additional and optional procedures required to support this pre-processing are defined in subclause 4.5.2. Extended measurements made by MS shall be forwarded to the BSC, using the same procedure as for ‘normal’ measurements. This case is described in subclause 4.5.3. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 18 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.5.1 Basic measurement reporting
|
This procedure is used by BTS to report the results of the basic radio measurements made by MS and TRX according to GSM 05.08 and GSM 05.05. The support of this procedure is mandatory in all BTS:s and all BSC:s. It is the default procedure to use unless otherwise indicated (see subclause 4.5.2.1). TRX reports all these measurements in MEASurement RESult messages to BSC. The sending of the MEASurement RESult messages is synchronized with the reception of SACCH blocks from MS. If an uplink SACCH block does not contain a MEASurement REPort or an EXTended MEASurement REPort (see subclause 4.5.3) from MS (e.g. when it sends a short message), only the uplink measurement results are included with an indication that the MS measurements are missing.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.5.2 Measurement pre-processing
|
These additional and optional procedures are included to support some pre-processing in BTS of radio measurement data. When used, they may replace the basic procedure defined in subclause 4.5.1. However, it shall be possible to change back to the basic procedure. Pre-processing in BTS must not affect the procedures on the A interface (e.g. the Handover Candidate Enquiry procedure).
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.5.2.1 Pre-processing configuration
|
This procedure is used by BSC to modify the pre-processing parameters according to reported communication conditions (e.g. degradation of the communication). In order to change the parameters, BSC sends a PREPROCESS CONFIGURE message to BTS. A parameter setting in the PREPROCESS CONFIGURE message indicates if the basic procedure defined in subclause 4.5.1 or pre-processing is to be used. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 19 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.5.2.2 Pre-processed measurement reporting
|
This procedure is used by BTS to report the results of measurement pre- processing. To report the results, BTS sends a PREPROCESSED MEASUREMENT RESULT message to BSC. The conditions to send the message are set in the PREPROCESS CONFIGURE message.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.5.3 Extended measurement reporting
|
This procedure is used by BTS to report the results of the extended measurements made by MS according to GSM 05.08. If an uplink SACCH block contains an EXTended MEASurement REPort from MS, it shall be forwarded to the BSC using the same procedure as when reporting regular measurement reports from an MS. Though, no measurement pre- processing is possible. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 20 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.6 Deactivate SACCH
|
This procedure is used by BSC to deactivate the SACCH at BTS according to the Channel Release procedure defined in GSM 04.08. When sending the Channel Release message to MS, BSC also sends the DEACTIVATE SACCH message to BTS to deactivate the SACCH (see GSM 04.08, Channel Release procedure).
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.7 Radio channel release
|
This procedure is used by BSC to release a radio channel which is no longer needed. When an activated radio channel is no longer needed, BSC sends an RF CHANnel RELease message to the relevant TRX and channel. After having released the addressed resources, the BTS sends a RF CHANnel RELease ACKnowledge to BSC.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.8 MS power control
|
This procedure is used by BSC to set the MS power level or the parameters required by TRX for the control of MS power. The initial parameters are set by BSC in the CHANNEL ACTIVATION message (see Channel Activation procedure). If these parameters are to be changed for an active channel, BSC sends a MS POWER CONTROL message to TRX. The support of the power control performed by BTS is optional. If power control is supported by BTS and it is to be used, this is indicated by optional parameters in the MS POWER CONTROL message (or the CHANNEL ACTIVATION message). Based on the measurements performed on the uplink, TRX then attempts to keep the power control parameters within the limits set by the MS POWER CONTROL message (or by the CHANNEL ACTIVATION message) by changing the MS Power Level field of the L1 header sent to MS in each SACCH block. MS confirms the power in the uplink L1 header. When the BTS supports MS power control the BSC can modify the MS power parameters during the connection (e.g. because of a classmark change) by sending a MS POWER CONTROL message containing the new parameters. The MS POWER CONTROL and the CHANNEL ACTIVATION message must also contain a maximum power permitted for the MS. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 21 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.9 Transmission power control
|
This is an optional procedure which is used between BSC and BTS to set the TRX transmission power level or the parameters required by TRX for the control of TRX transmission power. The initial parameters are set by BSC in the CHANNEL ACTIVATION message (see Channel Activation procedure). If these parameters are to be changed for an active channel, BSC sends a BS POWER CONTROL message to TRX. The support of the power control performed by BTS is optional. If power control is supported by BTS and it is to be used, this is indicated by optional parameters in the BS POWER CONTROL message (or the CHANNEL ACTIVATION message). Based on the Measurement Report messages sent by MS, the TRX will then attempt to keep the power control parameters within the limits set in the BS POWER CONTROL message (or by the CHANNEL ACTIVATION message) by changing the transmitted power on that channel. The maximum power of the TRX is determined from network planning criteria. However, BSC may indicate a lower maximum power in the BS POWER CONTROL message (or the CHANNEL ACTIVATION message).
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.10 Connection failure
|
This procedure is used by BTS to indicate to BSC that an active connection has been broken (e.g. due to a radio link failure as defined in GSM 05.08). When BTS detects that a connection has been broken, BTS sends a CONNection FAILure INDication message to BSC with the most proper cause value. Further actions are defined in GSM 04.08. Some possible cause values are: - radio link failure (as defined in GSM 05.08); - hardware failure (e.g. transcoder failure); - etc.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.11 Physical context request
|
This is an optional procedure which allows the BSC to obtain information on the "physical context" of a radio channel just prior to a channel change. This information may be forwarded to the new TRX (possibly in another collocated cell). The procedure is initiated by BSC sending a PHYsical CONTEXT REQuest message to TRX. TRX responds with a PHYsical CONTEXT CONFirm message which contains information on the "physical context" of the channel. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 22 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.12 SACCH information modify
|
This procedure is used by the BSC to modify the SACCH filling information (System Information) sent on an individual SACCH channel. For this purpose, the BSC sends a SACCH INFO MODIFY message to the BTS. The SACCH filling information as given in the SACCH INFO MODIFY message shall be used on the indicated channel until the channel is released or the information is changed by another SACCH INFO MODIFY message.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.13 Talker detection
|
The procedure is used by the BTS during the period the channel is activated for a voice group call. Upon detection of an MS on a channel activated for group call as specified in subclause 4.1, the BTS builds the VGCS UPLINK GRANT message as specified in GSM 04.08, sends the message to the MS in unacknowledged mode on the main signalling link and starts timer T3115. A TALKER DETection message is sent to the BSC. This message contains the measured delay of the access burst. If the timer expires before the reception of a correctly decoded frame from the MS, the BTS repeats the VGCS UPLINK GRANT message to the MS as specified in GSM 04.08. If the VGCS UPLINK GRANT message has been repeated Ny2 times without a correctly decoded frame being received from the MS, the BTS shall send a CONNECTION FAILURE INDICATION message to the BSC with cause value "talker access failure".
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.14 Listener detection
|
The procedure is used by the BTS during the period the channel is activated for a voice group call. Upon detection of an uplink access having the value reserved for replying to an uplink access request as specified in subclause 4.1. The BTS builds the LISTENER DETection message and sends the message to the BSC. This message contains the measured delay of the access burst.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.15 Remote Codec Configuration
|
This procedure is used by the BTS to report to the BSC the codec information received from the remote BSS prior to a MultiRate Codec TFO establishment or within TFO. This information can be used by the BSC to solve potential codec type and codec mode mismatches. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 23 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.16 Round Trip Delay Report
|
This procedure is used by the BTS to report to the BSC the BTS to Transcoder or BTS to Remote BTS round trip transmission delay. This information can be used by the BSC to set the correct timing for a pre-handover warning and to optimise the AMR Configuration and/or Adaptation algorithm.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.17 Pre-handover Warning
|
This procedure is used by the BSC to notify the serving BTS that a handover is going to be performed and allow the serving BTS to take the necessary steps in preparation of the handover (adaptation freezing for MultiRate Codec, TFO discontinuation,….). The Pre-handover Warning may disable (withdraw the “general authorisation” of ) the RATSCCH mechanism between BTS and MS for a while or permanently to ensure consistent configurations in BSC, BTSs and MS during and after handover. The BSC shall provide to the BTS the codec configuration parameters after Handover. In case the announced handover has failed, the BSC sends the Pre-handover Notification again to the serving BTS, this time with the codec configuration parameters as before the handover attempt in order to re-establish the BTS operation (adaptation enable for MultiRate Codec, TFO enable, RATSCCH authorisation, …).
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.18 MultiRate Codec Configuration Change
|
This procedure is used by the BSC to authorise the BTS to change the MultiRate Codec Configuration to solve a codec mismatch prior to TFO establishment or within TFO. The BTS shall use the RATSCCH inband signalling with the MS as defined by Rec GSM 05.09. Once the MultiRate Codec Configuration has been changed, the BTS shall send a MultiRate CODEC MOD ACK to the BSC to acknowledge the execution of the codec change. The MultiRate CODEC MOD ACK contains the final MultiRate Codec configuration. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 24 (GSM 08.58 version 7.4.1 Release 1998) If for any reason, the BTS is not able to complete the MultiRate Codec Configuration change, it should send a MultiRate CODEC MOD Negative ACK with the most appropriate cause. Possible causes are: tbd
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.19 MultiRate Codec Configuration Change Performed
|
This procedure is used by the BTS to report to the BSC that a MultiRate Codec Modification was performed using the RATSCCH in-band signalling capability. The BTS shall report the MultiRate codec configuration after the completion of the procedure.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.20 TFO Report
|
This procedure is used by the BTS to report to the BSC that TFO (based on AMR) is established, or is not in operation anymore.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
4.21 TFO Modification Request
|
This procedure is used by the BSC to change the TFO configuration while operating with AMR: enabling or disabling TFO. This procedure shall be used only during an established call. At call setup, Channel Activation procedure shall be used. During an in-call modification from data to speech, Mode Modify procedure shall be used. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 25 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
5 Common channel management procedures
| |
e1df81e32c85ac85801df65e6181a587
|
100 596
|
5.1 Channel request by MS
|
The procedure is initiated by TRX upon detection of a random access from an MS (CHANnel REQuest message from MS). TRX then sends a CHANnel ReQuireD message to BSC containing the Request Reference parameter (random number selected by MS plus some low order bits of the TDMA frame number for the access) and the measured delay of the Access Burst.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
5.2 Paging
|
This procedure is used to request the paging of one mobile station on a given paging subchannel. The paging of an MS is initiated by BSC sending a PAGing CoMmanD message to BTS. The message contains the MS identity (TMSI or IMSI), the paging population number of the MS, optionally an indication for the MS about which combination of channels will be needed for the subsequent transaction related to the paging and optionally an indication of the eMLPP priority of the call. The PAGing REQuest messages to be sent on the radio path are built and sent by BTS. The use by BTS of the "extended paging" facilities and the general downlink scheduling of the downlink CCCH is operator dependant and is not specified in this GTS. This process may also be influenced by O&M procedures.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
5.3 Delete indication
|
This procedure is used by BTS to indicate that due to overload on the downlink CCCH, an IMMEDIATE ASSIGN COMMAND has been deleted. For that purpose BTS sends a DELETE INDication message to BSC. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 26 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
5.4 CCCH load indication
|
This procedure is used by a BTS to inform the BSC of the load on a particular CCCH timeslot. The CCCH LOAD INDication message is sent regularly from BTS to BSC if the load exceeds some value set by O&M. The sending rate is also set by O&M.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
5.5 Broadcast information modify
|
This procedure is used by BSC to indicate to BTS the new information to be broadcast on BCCH. For that purpose, BSC sends a BCCH INFOrmation message to BTS.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
5.6 Short Message Cell Broadcast
|
Short Message Service Cell Broadcast messages are sent to BTS as SMS BROADCAST REQUEST or SMS BROADCAST COMMAND messages. With the SMS BROADCAST REQUEST mode of operation, the BSC handles the queuing, repetition and transmission of the messages taking the capacity of the CBCHs (basic and extended channel (see GSM 05.02)) into account. The BSC is also responsible for the segmentation of the SMS Cell Broadcast messages on the Radio interface: With the SMS BROADCAST COMMAND mode of operation, the BSC can request the broadcast of a complete Cell Broadcast message. The BSC handles the queuing, repetition and transmission of the messages taking the capacity of the CBCHs (basic and extended channel [see GSM 05.02]) into account. The BSC is responsible for the segmentation of the SMS Cell Broadcast messages on the Radio interface: ETSI ETSI TS 100 596 V7.4.1 (2000-05) 27 (GSM 08.58 version 7.4.1 Release 1998) With the SMS BROADCAST COMMAND mode of operation, the BSC can also set the BTS broadcast default mode. The BTS is then responsible for transmission of a default message when no other message is to be broadcast. Even though BSC handles the transmission of messages taking the capacity of CBCH into account, BTS can indicate to BSC if an overflow or underflow situation is about to happen in the CBCH. With the CBCH LOAD INDICATION mode of operation, the BTS can request immediate broadcast of m (=amount indicated in the CBCH Load Information element) scheduled SMSCB messages in the underflow situation. BSC shall transmit m scheduled messages and after that continue the broadcast of messages according to its own timetable. If BTS requests more messages than BSC is possessing, then BSC shall transmit only the amount it is possessing. CBCH LOAD INDICATION mode of operation could only be applied when DRX mode is used (see GSM 04.12). With the CBCH LOAD INDICATION mode of operation, the BTS can also request immediate stop of broadcast for a period of m (=amount indicated in the CBCH Load Information element) message slots in the overflow situation. BSC shall stop the broadcast for a period of m message slots and after that continue the broadcast of messages according to its own timetable. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 28 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
5.7 IMMEDIATE ASSIGNMENT
|
This procedure is used by BSC to request the transmission of an immediate assign message on downlink CCCH. To initiate the immediate assign, the BSC sends an IMMEDIATE ASSIGN COMMAND message. The message contains the complete immediate assign message as defined in GSM 04.08 (IMMEDIATE ASSIGNMENT or IMMEDIATE ASSIGNMENT EXTENDED or IMMEDIATE ASSIGNMENT REJECT) with the "Page Mode" element set to the value "no change". Upon receipt of the message, the BTS may transmit the immediate assignment message as received or combine several to construct the IMMEDIATE ASSIGNMENT EXTENDED or IMMEDIATE ASSIGNMENT REJECT. The BTS may also update the "Page Mode" element before transmission. The IMMEDIATE ASSIGNMENT EXTENDED message is either sent by the BSC in the IMMEDIATE ASSIGN COMMAND, or built by the BTS from up to two IMMEDIATE ASSIGN COMMAND messages. The IMMEDIATE ASSIGNMENT REJECT message is either sent by the BTS as received in the IMMEDIATE ASSIGN COMMAND message or built by the BTS from the contents of two or more IMMEDIATE ASSIGN COMMAND messages. For the latter case the BTS may consider request references with identical contents within the same message as duplicates and all but one may be suppressed. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 29 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
5.8 Notification
|
This procedure is used to request that notification be performed by the BTS. The BSC indicates the exact action required by the BTS in the command indicator. The NOTIFication messages to be sent on the radio path are built and sent by BTS. The BSC manages the NCH DRX information whilst the BTS manages the scheduling of the messages on the NCH. If the BTS for some reason can not perform the notification commanded by the BSC, then the BTS shall return an ERROR REPORT message with the relevant cause value.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
6 TRX management procedures
| |
e1df81e32c85ac85801df65e6181a587
|
100 596
|
6.1 Radio resource indication
|
This procedure is used to inform BSC on the interference levels on idle channels of a TRX. In the RF RESource INDication message, TRX reports the interference level for each of the channels which have been idle (not active) for the whole measurement period. See also GSM 08.08, subclause 3.1.3.1 and GSM 05.08, subclause 3.1 e) of appendix A. The RF RESource INDication message is sent regularly with a rate set by O&M. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 30 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
6.2 SACCH filling information modify
|
This procedure is used by BSC to indicate to BTS the new information to be used as filling information on SACCHs. For that propose BSC sends a SACCH FILLing message to BTS.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
6.3 Flow control
|
This procedure is defined to give some degree of flow control. It can be used for TRX processor overload, downlink CCCH overload and ACCH overload. The algorithm used in BSC to control the traffic flow is as follows. Upon receipt of the first OVERLOAD message, BSC reduces the traffic by one step and starts timers T1 and T2. During T1 all OVERLOAD messages are ignored in order not to reduce the traffic too rapidly. Reception of an OVERLOAD message after T1 but still during T2 will decrease the traffic by one more step and timers T1 and T2 are restarted. This step by step reduction of traffic is continued until maximum reduction is obtained. If T2 expires (i.e. no OVERLOAD message was received during T2), the traffic will be increased by one step and T2 restarted. This step by step increase of traffic will be continued until full load has been resumed. The number of steps and the method of reducing the load is considered to be implementation dependent. For example, the amount of random accesses and thereby access grants can be reduced by use of the RACH Control parameters (e.g. Access Control Class or Cell Barred) or the Cell Selection parameters (e.g. CELL-RESELECT-HYSTERESIS or RXLEV- ACCESS-MIN) in the system information messages of GSM 04.08. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 31 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
6.4 Error reporting
|
This procedure is used by BTS to report detected errors as described in clause 7 below if they cannot be reported by any other procedure. When TRX detects the reception of an erroneous message, it sends an ERROR REPORT message to BSC with the most appropriate cause value. In order to identify the erroneous message, the Message Type, the Channel Number, the Link Identifier and/or the complete erroneous message can be included.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
6a Location services procedures
|
These procedures are related to Location Services (LCS).
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
6a.1 LLP message transport
|
This procedure is used to convey LLP messages between the BTS-or Standalone Type B LMU and the BSC, as defined in the Location Services (LCS) Stage 2 document GSM 03.71. The sending entity (BSC, Standalone Type B LMU or BTS) sends a Location Information message containing an embedded LLP message to the receiving entity (BSC, Standalone Type B LMU or BTS).
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
7 Error handling
| |
e1df81e32c85ac85801df65e6181a587
|
100 596
|
7.1 General
|
The procedures specified above apply to those messages which pass the checks described below. The behaviour of BSC in erroneous cases is implementation dependent. The behaviour of BTS in erroneous cases is to ignore the message and to send a report to BSC. The report can be sent in either of the following messages: - CHANNEL ACTIVATION NACK in connection with channel activations; - MODE MODIFY NACK in connection with a channel mode change; - ERROR REPORT in other cases. For procedures controlled by the BSC, and in particular procedures where the BSC sends a request for resources at the BTS and waits for an acknowledge, the implementation in the BSC must provide means for avoiding deadlock situations at the BTS as e.g. hanging resources. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 32 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
7.2 Message discriminator error
|
A message with a non-specified message discriminator is erroneous.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
7.3 Message type error
|
A message with a non-specified message type is considered correct, but is ignored by BTS.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
7.4 Message sequence error
|
A message with an existing message type which is not possible according to the specification and to the state of the BTS is erroneous.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
7.5 General information element errors
|
This category includes: - information element out of sequence; - abnormally duplicated element; - missing element. A message with such an error is erroneous.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
7.6 Mandatory information element errors
|
This includes: a) non-existing element type; b) information length error; c) content which does not comply with the specification (value reserved for future use is considered as case d)); d) value indicated as reserved for future use; e) bits reserved for future use not set to 0; f) content complying with specification but incompatible with the state; g) content complying with the specification but inconsistent. All cases except e) are considered erroneous. In case e), BTS simply ignores the reserved (RFU) bits.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
7.7 Optional information element errors
|
The same categories of errors as in previous subclause apply. In cases other than b), e), f) and g), BTS ignores the element and processes the rest of the message. Cases b), f) and g) are considered erroneous. In case e), BTS ignores the reserved (RFU) bits. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 33 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
7.8 Conditional information element errors
|
The same categories of errors as in subclause 7.6 apply. If the conditions for presence of the element are met, the same erroneous cases as in subclause 7.6 apply. If the conditions for presence of the element are not met, the same erroneous cases as in subclause 7.7 apply.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8 Message formats and contents
|
This clause defines the format and contents of the messages sent over the A-bis interface. Similar coding principles as in recs. 04.08 and 08.08 are used. For each message, the contained Information Elements are listed. For each Information Element, the following information is given: - Name of Information Element; - Reference section for the coding of the Information Element; - Presence condition for the Information Element: M Mandatory, must always be present; receiver: if not present, consider message erroneous; C Conditional, presence depending on e.g. a) value of other element; b) presence of optional element; receiver: if not present when condition met, consider message erroneous, else accept message; O Optional, receiver: present or not, accept message; - Format of Information Element: TType only, fixed length, only Element Identifier; V Value only, fixed length, no Element Identifier included; TV Type and Value, fixed length, Element Identifier included; TLV Type, Length and Value, variable length, Element Identifier and Length Indicator included; - Total length of Information Element; for variable length, lower and upper limits. NOTE: Maximum message length is determined by the N201 parameter of GSM 08.56. In a message, the message discriminator is transmitted first. The purpose is to distinguish between transparent messages (T-bit set to 1) and non-transparent messages (T-bit set to 0) and also between messages related to Radio Link Layer Management, Dedicated Channel Management, Common Channel Management and TRX Management. The octets are sent in the order shown in the description of the messages and information elements. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 34 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.1 Transparent messages
|
Transparent messages are used at the A-bis interface to convey layer 3 messages for the radio interface as defined in GSM 04.08 and for which BTS has to take or has taken no specific action. The T- bit of the Message Discriminator is set to 1. In the uplink direction (messages from MS), all messages received in I- frames and all messages received in UI-frames except for the MEASurement REPort message are considered as transparent. They are forwarded to BSC as DATA INDication and UNIT DATA INDication messages respectively. In the downlink direction (messages to MS) all messages as defined in GSM 04.08 are transparent except for the following messages, which are replaced by BSC-BTS specific messages over the A- bis interface and where BTS will send the corresponding L3 message over the radio interface after the necessary actions have been taken: Message to MS Replaced on A-bis interface by CIPHering MODe CoMmanD ENCRyption CoMmanD PAGing REQuest PAGing CoMmanD NOTIFication NOTIFication CoMmanD SYSTEM INFOrmation BCCH INFOrmation and SACCH FILLing EXTENDED MEASUREMENT ORDER SACCH FILLing Immediate assign (3 types) IMMEDIATE ASSIGN COMMAND Transparent messages are sent by BSC as DATA REQuest or UNIT DATA REQuest messages.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.2 Non-transparent messages (BSC-BTS specific messages)
|
These messages are used over the A-bis interface for messages on which BTS has to take some action (BSC to BTS direction) and for messages which are the result from actions taken by BTS (BTS to BSC direction). The T-bit of the Message Discriminator is set to 0.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.3 Radio link layer management messages
|
These messages are related to Radio Link Layer Management procedures. They all have the following general format: INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Link Identifier 9.3.2 M TV 2 (Information elements depending on message type) ETSI ETSI TS 100 596 V7.4.1 (2000-05) 35 (GSM 08.58 version 7.4.1 Release 1998) The messages concerned are the following: Message name Reference section DATA REQuest 8.3.1 DATA INDication 8.3.2 ERROR INDication 8.3.3 ESTablish REQuest 8.3.4 ESTablish CONFirm 8.3.5 ESTablish INDication 8.3.6 RELease REQuest 8.3.7 RELease CONFirm 8.3.8 RELease INDication 8.3.9 UNIT DATA REQuest 8.3.10 UNIT DATA INDication 8.3.11
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.3.1 DATA REQUEST
|
This message is sent from BSC to BTS to request the sending of a message in acknowledged mode on a radio link layer connection. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Link Identifier 9.3.2 M TV 2 L3 Information 9.3.11 M TLV >=3
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.3.2 DATA INDICATION
|
This message is sent from BTS to BSC to indicate the reception of a message in acknowledged mode on a radio link layer connection. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Link Identifier 9.3.2 M TV 2 L3 Information 9.3.11 M TLV >=3 ETSI ETSI TS 100 596 V7.4.1 (2000-05) 36 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.3.3 ERROR INDICATION
|
This message is sent from BTS to BSC to indicate an abnormal case for a radio link layer connection. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Link Identifier 9.3.2 M TV 2 RLM Cause 9.3.22 M TLV 2-4
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.3.4 ESTABLISH REQUEST
|
This message is sent from BSC to BTS to request the establishment of a multi-frame mode (acknowledged mode) link layer connection on the radio path. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Link Identifier 9.3.2 M TV 2
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.3.5 ESTABLISH CONFIRM
|
This message is sent from BTS to BSC to confirm the establishment of a radio link layer connection in multi-frame (acknowledged) mode. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Link Identifier 9.3.2 M TV 2 ETSI ETSI TS 100 596 V7.4.1 (2000-05) 37 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.3.6 ESTABLISH INDICATION
|
This message is sent from BTS to BSC to indicate the establishment of a radio link layer connection in multi-frame mode, initiated by an MS. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Link Identifier 9.3.2 M TV 2 L3 Information 9.3.11 O 1) TLV 3-23 1) The L3 Information field is present only if the SABM frame contained a non-empty information field. NOTE: The "establish mode" parameter appearing in GSM 04.06 is used only on the MS side.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.3.7 RELEASE REQUEST
|
This message is sent from BSC to BTS to request the release of multi- frame mode of a radio link layer connection. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Link Identifier 9.3.2 M TV 2 Release Mode 9.3.20 M TV 2
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.3.8 RELEASE CONFIRM
|
This message is sent from BTS to BSC to confirm the release of multi- frame mode of a radio link layer connection. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Link Identifier 9.3.2 M TV 2 ETSI ETSI TS 100 596 V7.4.1 (2000-05) 38 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.3.9 RELEASE INDICATION
|
This message is sent from BTS to BSC to indicate the release of a radio link layer connection (initiated by MS). INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Link Identifier 9.3.2 M TV 2
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.3.10 UNIT DATA REQUEST
|
This message is sent from BSC to BTS to request the sending of a message in unacknowledged mode on a radio link layer connection. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Link Identifier 9.3.2 M TV 2 L3 Information 9.3.11 M TLV 3-25
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.3.11 UNIT DATA INDICATION
|
This message is sent from BTS to BSC to indicate the reception of a message in unacknowledged mode on a radio link layer connection. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Link Identifier 9.3.2 M TV 2 L3 Information 9.3.11 M TLV 3-23
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.4 DEDICATED CHANNEL MANAGEMENT MESSAGES
|
These messages are related to Dedicated Channel Management procedures. They all have the following general format: INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 (Information elements depending on message type) ETSI ETSI TS 100 596 V7.4.1 (2000-05) 39 (GSM 08.58 version 7.4.1 Release 1998) The messages concerned are the following: Message name Reference section CHANnel ACTIVation 8.4.1 CHANnel ACTIVation ACKnowledge 8.4.2 CHANnel ACTIVation Negative ACK 8.4.3 CONNection FAILure INDication 8.4.4 DEACTIVATE SACCH 8.4.5 ENCRyption CoMmanD 8.4.6 HANDOver DETection 8.4.7 TALKER DETection 8.4.21 LISTENER DETection 8.4.22 MEASurement RESult 8.4.8 MODE MODIFY REQuest
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.4.9 MODE MODIFY
|
ACKnowledge 8.4.10 MODE MODIFY Negative ACKnowledge 8.4.11 PHYsical CONTEXT REQuest 8.4.12 PHYsical CONTEXT CONFirm 8.4.13 RF CHANnel RELease 8.4.14 MS POWER CONTROL 8.4.15 BS POWER CONTROL 8.4.16 PREPROCecc CONFIGure 8.4.17 PREPROCessed MEASurement RESult 8.4.18 RF CHANnel RELease ACKnowledge 8.4.19 SACCH INFO MODIFY 8.4.20 REMOTE CODEC CONFiguration REPort 8.4.23 Round Trip Delay REPort 8.4.24 PRE-HANDOver NOTIFication 8.4.25 MultiRate CODEC MODification REQuest 8.4.26 MultiRate CODEC MOD ACKnowledge 8.4.27 MultiRate CODEC MOD Negative ACK 8.4.28 MultiRate CODEC MOD PERformed 8.4.29 TFO REPort 8.4.30 TFO MODification REQuest 8.4.31 ETSI ETSI TS 100 596 V7.4.1 (2000-05) 40 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.4.1 CHANNEL ACTIVATION
|
This message is sent from BSC to BTS in order to activate a radio channel. The attributes of the channel are defined in the message. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Activation Type 9.3.3 M TV 2 Channel Mode 9.3.6 M TLV 8-9 Channel Identification 9.3.5 O 7) TLV 8 Encryption information 9.3.7 O 1) TLV >=3 Handover Reference 9.3.9 C 2) TV 2 BS Power 9.3.4 O 3) TV 2 MS Power 9.3.13 O 3) TV 2 Timing Advance 9.3.24 C 3) 4) TV 2 BS Power Parameters 9.3.32 O 5) TLV >=2 MS Power Parameters 9.3.31 O 5) TLV >=2 Physical Context 9.3.16 O 6) TLV >=2 SACCH Information 9.3.29 O 8) TLV >=3 UIC 9.3.50 O 9) TLV 3 Main channel reference 9.3.45 O 10) TV 2 MultiRate configuration 9.3.52 O 11) TLV >=4 MultiRate Control 9.3.53 O 12) TV 2 Supported Codec Types 9.3.54 O 12) TLV >=5 1) The Encryption Information element is only included if ciphering is to be applied. 2) The Handover Reference element is only included if activation type is handover. 3) If BS Power, MS Power and/or Timing Advance elements are present, they are to be used to set the initial transmission power and the initial L1-header. 4) The Timing Advance element must be included if activation type is intra cell channel change. 5) The BS and MS Power Parameters elements are included to indicate that BS and/or MS power control is to be performed by BTS. The maximum power to be used is indicated in the BS and MS Power elements respectively. 6) Optional element for additional physical channel information. 7) Included if compatibility with phase1 is required. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 41 (GSM 08.58 version 7.4.1 Release 1998) 8) Optional element for setting the SACCH filling information individually for this channel. If this element is present, the SACCH filling information as given by this element shall be used for this channel (replacing any SACCH filling information as given by the SACCH FILLING message(s)) until the channel is released or the information is changed by a SACCH INFO MODIFY message. (If this element is not present, the SACCH filling as given by the SACCH FILLING message(s) shall be used.) 9) The UIC element may be included for voice group calls. It is used in the same way as the BSIC for decoding the random access bursts when decoding uplink access bursts. If not included, the BSIC shall be used for decoding uplink access bursts. 10) Optional element for multislot operation, it may be used in case of power control in the BTS. 11) Included if the Channel Mode indicates that a multi-rate speech codec is used. 12) Optionally included if the Channel Mode indicates that a multi-rate speech codec is used and TFO control is required or to give to the BTS the possibility to change autonomously the multi-rate codec configuration.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.4.2 CHANNEL ACTIVATION ACKNOWLEDGE
|
This message is sent from BSC to BTS to acknowledge that the requested channel activation has been completed correctly. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Frame number 9.3.8 M TV 3 The Frame Number element is used by BSC to calculate the Starting Time parameter when required.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.4.3 CHANNEL ACTIVATION NEGATIVE ACKNOWLEDGE
|
This message is sent from BTS to BSC to indicate that the channel activation could not be performed as requested. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Cause 9.3.26 M TLV >=3 If the Channel Activation message was received with an erroneous Channel number information element, the Channel Activation Negative Acknowledge message is returned with the Channel Number information element equal to the received (and erroneous) Channel number and the Cause value "Mandatory Information Element Error" with Diagnostics equal to the Channel number element identifier value. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 42 (GSM 08.58 version 7.4.1 Release 1998)
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.4.4 CONNECTION FAILURE INDICATION
|
This message is sent from BTS to BSC to indicate that an active connection has been broken for some reason. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Cause 9.3.26 M TLV >=3
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.4.5 DEACTIVATE SACCH
|
This message is sent from BSC to BTS in order to deactivate the SACCH of an active channel. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.4.6 ENCRYPTION COMMAND
|
This message is sent from BSC to BTS to start ciphering mode operation. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Encryption information 9.3.7 M TLV >=3 Link Identifier 9.3.2 M TV 2 L3 Info (CIPH MOD CMD) 9.3.11 M TLV 6 The L3 Info element contains the complete Ciphering Mode Command message as defined in GSM 04.08.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.4.7 HANDOVER DETECTION
|
This message is sent from BTS to BSC when BTS correctly receives information from an MS on the handover activated channel. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Access Delay 9.3.17 O 1) TV 2 ETSI ETSI TS 100 596 V7.4.1 (2000-05) 43 (GSM 08.58 version 7.4.1 Release 1998) 1) The Access Delay element is included if the sending of the handover detection message was triggered by the reception of a handover access burst with the correct handover reference.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.4.8 MEASUREMENT RESULT
|
This message from BTS to BSC is used to report to BSC the results of radio channel measurements made by BTS (uplink) and to convey the measurement reports from MS received on SACCH and in the L1 headers. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Measurement result number 9.3.27 M TV 2 Uplink Measurements 9.3.25 M TLV >=5 BS Power 9.3.4 M TV 2 L1 Information 9.3.10 O 1) TV 3 L3 Info(MEAS REP or EXT MEAS REP) 9.3.11 O 1) TLV 21 MS Timing Offset 9.3.37 O 2) TV 2 1) The L1 Information element contains the last received L1-header (MS Power and Timing Advance) from MS and the L3 Information element contains the complete MEASurement REPort message or EXTended MEASurement REPort message freceived from MS. They are included only if received since last (EXTended) MEASurement RESult message. 2) MS Timing Offset can be optionally included to increase the accuracy of possible distance measurements. 8.4.9 MODE MODIFY This message is sent from BSC to BTS to request a change of channel mode of an active channel. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Channel Mode 9.3.6 M TLV 8-9 Encryption information 9.3.7 O 1) TLV >=3 Main channel reference 9.3.45 O 2) TV 2 MultiRate configuration 9.3.52 O 3) TLV >=3 Multirate Control 9.3.53 O 4) TV 2 Supported Codec Types 9.3.54 O 4) TLV >=5 1) The Encryption Information element is only included if ciphering is to be applied. 2) Optional element for multislot operation, it may be used in case of power control in the BTS. 3) Included if the Channel Mode indicates that a multi-rate speech codec is used. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 44 (GSM 08.58 version 7.4.1 Release 1998) 4) Optionally included if the Channel Mode indicates that a multi-rate speech codec is used and TFO control is required or to give to the BTS the possibility to change autonomously the multi-rate codec configuration.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.4.10 MODE MODIFY ACKNOWLEDGE
|
This message is sent from BTS to BSC to confirm the change of channel mode of an active channel. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.4.11 MODE MODIFY NEGATIVE ACKNOWLEDGE
|
This message is sent from BTS to BSC to indicate that the channel mode modification could not be performed as requested. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 Cause 9.3.26 M TLV >=3
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.4.12 PHYSICAL CONTEXT REQUEST
|
This message is sent from BSC to BTS to request the "physical context" of an active channel. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.4.13 PHYSICAL CONTEXT CONFIRM
|
This message is sent from BTS to BSC as a response to a PHYsical CONTEXT REQuest message. The message contains the "physical context" information. ETSI ETSI TS 100 596 V7.4.1 (2000-05) 45 (GSM 08.58 version 7.4.1 Release 1998) INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2 BS Power 9.3.4 M TV 2 MS Power 9.3.13 M TV 2 Timing Advance 9.3.24 M TV 2 Physical Context 9.3.16 O 1) TLV >=2 1) Optional element for additional physical channel information.
|
e1df81e32c85ac85801df65e6181a587
|
100 596
|
8.4.14 RF CHANNEL RELEASE
|
This message is sent from BSC to BTS to inform that a radio channel is no longer needed. INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH Message discriminator 9.1 M V 1 Message type 9.2 M V 1 Channel number 9.3.1 M TV 2
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.