SIST EN 300 979 V6.0.1:2003
(Main)Digital cellular telecommunications system (Phase 2+) (GSM); In-band control of remote transcoders and rate adaptors for half rate traffic channels (GSM 08.61 version 6.0.1 Release 1997)
Digital cellular telecommunications system (Phase 2+) (GSM); In-band control of remote transcoders and rate adaptors for half rate traffic channels (GSM 08.61 version 6.0.1 Release 1997)
Upgrade from Phase 2+ to Release 1997
Digitalni celični telekomunikacijski sistem (faza 2+) – Znotrajpasovno krmiljenje oddaljenih prekodirnikov in prilagodilnikov hitrosti pri prometnih kanalih s polovično hitrostjo govora (GSM 08.61, različica 6.0.1, izdaja 1997)
General Information
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Digital cellular telecommunications system (Phase 2+) (GSM); In-band control of remote transcoders and rate adaptors for half rate traffic channels (GSM 08.61 version 6.0.1 Release 1997)33.070.50Globalni sistem za mobilno telekomunikacijo (GSM)Global System for Mobile Communication (GSM)ICS:Ta slovenski standard je istoveten z:EN 300 979 Version 6.0.1SIST EN 300 979 V6.0.1:2003en01-december-2003SIST EN 300 979 V6.0.1:2003SLOVENSKI
STANDARD
EN 300 979 V6.0.1 (1999-09)European Standard (Telecommunications series)Digital cellular telecommunications system (Phase 2+);In-band control of remote transcoders and rate adaptors forhalf rate traffic channels(GSM 08.61 version 6.0.1 Release 1997)GLOBAL SYSTEM
FOR MOBILE COMMUNICATIONSRSIST EN 300 979 V6.0.1:2003
ETSIEN 300 979 V6.0.1 (1999-09)2(GSM 08.61 version 6.0.1 Release 1997)ReferenceDEN/SMG-020861Q6 (92c0300o.PDF)KeywordsDigital cellular telecommunications system,Global System for Mobile communications (GSM)ETSIPostal addressF-06921 Sophia Antipolis Cedex - FRANCEOffice address650 Route des Lucioles - Sophia AntipolisValbonne - FRANCETel.: +33 4 92 94 42 00
Fax: +33 4 93 65 47 16Siret N° 348 623 562 00017 - NAF 742 CAssociation à but non lucratif enregistrée à laSous-Préfecture de Grasse (06) N° 7803/88Internetsecretariat@etsi.frIndividual copies of this ETSI deliverablecan be downloaded fromhttp://www.etsi.orgIf you find errors in the present document, send yourcomment to: editor@etsi.frCopyright NotificationNo part may be reproduced except as authorized by written permission.The copyright and the foregoing restriction extend to reproduction in all media.© European Telecommunications Standards Institute 1999.All rights reserved.SIST EN 300 979 V6.0.1:2003
ETSIEN 300 979 V6.0.1 (1999-09)3(GSM 08.61 version 6.0.1 Release 1997)ContentsIntellectual Property Rights.5Foreword.51Scope.62References.63Definitions and abbreviations.73.1Definitions.73.2Abbreviations.74General approach.75Frame structure.95.116 kbit/s submultiplexing.95.1.1Speech frame.95.1.2Data frame.105.1.3O&M frame.115.1.4Coding.115.1.4.1Coding of speech frames.115.1.4.2Coding of data frames.135.1.4.3Coding of O&M frames.135.28 kbit/s submultiplexing.145.2.1Speech frame.145.2.2Data frame.145.2.3O&M frame.155.2.4Coding.155.2.4.1Uplink coding.155.2.4.2Downlink coding.175.3Order of Bit Transmission.186Procedures.186.1Remote Control of Transcoders and Rate Adaptors.186.2Resource Allocation.186.3Resource Release.196.4In Call Modification.196.5Handling of missing data.196.6Procedures for Speech Frames.206.6.1Time Alignment of Speech Frames.206.6.1.116 kbit/s submultiplexing.206.6.1.1.1Downlink Time Alignment.206.6.1.1.1.1Initial Time Alignment state.206.6.1.1.1.2Static Time Alignment state.216.6.1.1.2Uplink Time Alignment.236.6.1.1.3Initiation at Resource Allocation.236.6.1.1.4Time Alignment during Handover.236.6.1.28 kbit/s submultiplexing.236.6.1.2.1Downlink Time Alignment.236.6.1.2.2Uplink Time Alignment.256.6.1.2.3Initiation at Resource allocation.266.6.1.2.4Time Alignment during handover.266.6.2Procedures for Discontinuous Transmission (DTX).266.6.2.1DTX procedures in the uplink direction.266.6.2.2DTX procedures in the downlink direction.266.7Procedures for Data Frames.276.7.1The RAA Function.276.7.2The RA1/RA1' Function.286.7.3The RA2 Function.28SIST EN 300 979 V6.0.1:2003
ETSIEN 300 979 V6.0.1 (1999-09)4(GSM 08.61 version 6.0.1 Release 1997)6.7.4Procedures for 8 kbit/s intermediate rate adaption rate.286.7.5Support of Non-Transparent Bearer Applications.286.8Frame Synchronization.296.8.116 kbit/s submultiplexing.296.8.1.1Search for Frame Synchronization.296.8.1.2Frame Synchronization After Performing Downlink Timing Adjustments.296.8.1.3Frame Synchronization Monitoring and Recovery.296.8.28 kbit/s submultiplexing.306.8.2.1Search for Frame Synchronization.306.8.2.2Frame Synchronization Monitoring and Recovery.306.9Correction/detection of bit errors.306.9.116 kbit/s submultiplexing.306.9.1.1Error Detection on the Control Bits.306.9.1.1.1General Procedure.306.9.1.1.2Speech Frames.306.9.1.2Handling of frames received with errors.306.9.28 kbit/s submultiplexing.316.9.2.1Error Detection on the Control Bits.316.9.2.2Handling of frames received with errors.316.10Procedures for Operation & Maintenance.316.10.1Transfer of O&M Information Between the TRAU and the BSC.316.10.2Procedures in the TRAU.326.10.3Procedures in the BSC.326.10.3.1Use of O&M Frames.326.10.4Procedures in the BTS.32Annex A (informative):Change Request History.33History.34SIST EN 300 979 V6.0.1:2003
ETSIEN 300 979 V6.0.1 (1999-09)5(GSM 08.61 version 6.0.1 Release 1997)Intellectual Property RightsIPRs essential or potentially essential to the present document may have been declared to ETSI. The informationpertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be foundin SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respectof ETSI standards", which is available free of charge from the ETSI Secretariat. Latest updates are available on theETSI Web server (http://www.etsi.org/ipr).Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guaranteecan be given as to the existence of other IPRs not referenced in SR 000 314 (or the updates on the ETSI Web server)which are, or may be, or may become, essential to the present document.ForewordThis European Standard (Telecommunications series) has been produced by the Special Mobile Group (SMG).The present document defines the protocol between the Base Transceiver Station (BTS) and the remote Transcoder/RateAdaption Unit (TRAU) for half rate speech and half rate data, within the digital cellular telecommunications system.The contents of the present document is subject to continuing work within SMG and may change following formal SMGapproval. Should SMG modify the contents of the present document it will be re-released with an identifying change ofrelease date and an increase in version number as follows:Version 6.x.ywhere:6indicates Release 1997 of GSM Phase 2+xthe second digit is incremented for all changes of substance, i.e. technical enhancements, corrections, updates,etc.ythe third digit is incremented when editorial only changes have been incorporated in the specification.Proposed national transposition datesDate of adoption of this EN:3 September 1999Date of latest announcement of this EN (doa):31 December 1999Date of latest publication of new National Standardor endorsement of this EN (dop/e):30 June 2000Date of withdrawal of any conflicting National Standard (dow):30 June 2000SIST EN 300 979 V6.0.1:2003
ETSIEN 300 979 V6.0.1 (1999-09)6(GSM 08.61 version 6.0.1 Release 1997)1ScopeThe present document describes the protocol between the Base Transceiver Station (BTS) and the remoteTranscoder/Rate Adaption Unit (TRAU) for speech and data on half rate traffic channel (TCH/H).The protocol is specified for 8 kbit/s and 16 kbit/s submultiplexing scheme.The present document should be considered together with the GSM 06 series, GSM 04.21 (Rate Adaption on theMS-BSS Interface) and GSM 08.20 (Rate Adaption on the BTS/MSC Interface).2ReferencesThe following documents contain provisions which, through reference in this text, constitute provisions of the presentdocument.· References are either specific (identified by date of publication, edition number, version number, etc.) ornon-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 samenumber.· For this Release 1997 document, references to GSM documents are for Release 1997 versions (version 6.x.y).[1]GSM 01.02: "Digital cellular telecommunication system (Phase 2+); General description of a GSMPublic Land Mobile Network (PLMN)".[2]GSM 01.04: "Digital cellular telecommunication system (Phase 2+); Abbreviations and acronyms".[3]GSM 04.21: "Digital cellular telecommunications system (Phase 2+); Rate adaption on the MobileStation - Base Station System (MS - BSS) interface".[4]GSM 05.03: "Digital cellular telecommunications system (Phase 2+); Channel coding".[5]GSM 06.21: "Digital cellular telecommunications system (Phase 2+); Half rate speech;Substitution and muting of lost frames for half rate speech traffic channels".[6]GSM 06.22: "Digital cellular telecommunications system (Phase 2+); Half rate speech; Comfortnoise aspects for half rate speech traffic channels".[7]GSM 06.41: "Digital cellular telecommunications system (Phase 2+); Half rate speech;Discontinuous Transmission (DTX) for half rate speech traffic channels".[8]GSM 06.42: "Digital cellular telecommunications system (Phase 2+); "Half rate speech; VoiceActivity Detector (VAD) for half rate speech traffic channels".[9]GSM 08.08: "Digital cellular telecommunication system (Phase 2+); Mobile Switching Centre -Base Station System (MSC - BSS) interface Layer 3 specification".[10]GSM 08.20: "Digital cellular telecommunication system (Phase 2+); Rate adaption on the BaseStation System - Mobile-services Switching Centre (BSS - MSC) interface".[11]GSM 08.52: "Digital cellular telecommunication system (Phase 2+); Base Station Controller -Base Transceiver Station (BSC - BTS) interface Interface principles".[12]GSM 08.54: "Digital cellular telecommunication system (Phase 2+); Base Station Controller -Base Transceiver Station (BSC - BTS) interface Layer 1 structure of physical circuits".SIST EN 300 979 V6.0.1:2003
ETSIEN 300 979 V6.0.1 (1999-09)7(GSM 08.61 version 6.0.1 Release 1997)[13]GSM 08.58: "Digital cellular telecommunication system (Phase 2+); Base Station Controller -Base Transceiver Station (BSC - BTS) interface Layer 3 specification".[14]GSM 12.21: "Digital cellular telecommunication system (Phase 2); Network Management (NM)procedures and messages on the A-bis interface".[15]ITU-T Recommendation I.460: "Multiplexing, rate adaption and support of existing interfaces".[16]ITU-T Recommendation V.110: "Support of data terminal equipments (DTEs) with V-Seriesinterfaces by an integrated services digital network".3Definitions and abbreviations3.1DefinitionsNo specific definitions apply to the present document.3.2AbbreviationsFor the purposes of the present document, the following abbreviations apply:BSCBase Station ControllerBTSBase Transceiver StationCCUChannel Codec UnitRARate AdaptionTRAUTranscoder and Rate Adaption UnitOther abbreviations used in the present document are listed in GSM 01.04.4General approachThe TRAU shall be controlled by the BTS when it is positioned remote from the BTS. In this case, the speech/datainformation and TRAU control signals exchanged between the Channel Codec Unit (CCU) in the BTS and the TRAUshall be transferred in frames denoted "TRAU frames".The TRAU frames may be carried by either 16 kbit/s traffic channels or 8 kbit/s channels. The choice of the trafficchannel bit rate or submultiplexing scheme is operator dependent.The TRAU frames have a fixed length of:-160 bits (20 ms) when 8 kbit/s submultiplexing is used;-320 bits (20 ms) when 16 kbit/s submultiplexing is used.The protocol between the BTS and the TRAU should be the same if the TRAU is positioned either at the MSC site or atthe BSC site. In the first case, the BSC should be considered as transparent for 16 kbit/s and 8 kbit/s channels.The TRAU is considered a part of the BSC when the TRAU is remote from the BTS (see GSM 08.52), and thesignalling between the BSC and the TRAU (e.g. detection of call release, handover and transfer of O&M information)may be performed by using BSC internal signals. However, the signalling between the CCU and the TRAU, usingTRAU frames as specified in the present document, is mandatory when the TRAU is remote from the BTS.For data transfer, a conversion function is required, in addition to the conversion/rate adaption specified in GSM 08.20,to adapt ITU-T V.110 frames to the TRAU data frames. This function constitutes the RAA.NOTE:If standard 64 kbit/s switching is used in the BSC, multiplexing according to ITU-T RecommendationI.460 should apply at both sides of the switch.SIST EN 300 979 V6.0.1:2003
ETSIEN 300 979 V6.0.1 (1999-09)8(GSM 08.61 version 6.0.1 Release 1997)A possible configuration of the TRAU and the CCU is shown in figure 4.1.The functions inside the TRAU are:-"Remote Transcoder and Rate Adaptor Control Function" (RTRACF);-"Remote Speech Handler Function" (RSHF);-the RAA function;-the RA2 function;-the transcoder function.The functions inside the CCU are:-"Transcoder and Rate Adaptor Control Function" (TRACF);-"Speech Handler Function" (SHF);-the RAA function;-the RA1/RA1' function;-the channel codec function.The present document does not describe the procedures inside the TRAU and the CCU. The layout in figure 4.1 is onlyintended as a reference model.Transcoderand RAControlFunctionRemoteTranscoderand RAControlFunctionRAARA2RA1RA1'ChannelCodecFunctionDataControlSpeech/DataRemoteSpeechHandlerFunctionRadioframesSpeech64kbit/s8kbit/s16 kbit/s320bit/20ms160bit/20msSpeechHandlerFunctionTranscoderFunction(note)L3 controlsignalsRAADataSpeechNOTE:This technical specification assumes the DTX handler function to be part of the Transcoder Function.Figure GSM 08.61/4.1: Functional entities for handling of control of remote transcoders and rateadaptorsSIST EN 300 979 V6.0.1:2003
ETSIEN 300 979 V6.0.1 (1999-09)9(GSM 08.61 version 6.0.1 Release 1997)5Frame structure5.116 kbit/s submultiplexing5.1.1Speech frameBit numberOctet no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
ETSIEN 300 979 V6.0.1 (1999-09)10(GSM 08.61 version 6.0.1 Release 1997)5.1.2Data frameBit numberOctet no.123456781000000002000000031C1C2C3C4C5C6C74C8C9C10C11C12C13C14C1551D1D2D3D4D5D6D761D8D9D10D11D12D13D1471D15D16D17D18D19D20D2181D22D23D24D25D26D27D28Data frame91D29D30D31D32D33D34D35position 1101D36D37D38D39D40D41D42111D43D44D45D46D47D48D49121D50D51D52D53D54D55D56131D57D58D59D60D61D62D63141111111115111111111611111111171111111118111111111911111111201111111121111111112211111111231D'1D'2D'3D'4D'5D'6D'7241D'8D'9D'10D'11D'12D'13D'14251D'15D'16D'17D'18D'19D'20D'21261D'22D'23D'24D'25D'26D'27D'28Data frame271D'29D'30D'31D'32D'33D'34D'35position 3281D'36D'37D'38D'39D'40D'41D'42291D'43D'44D'45D'46D'47D'48D'49301D'50D'51D'52D'53D'54D'55D'56311D'57D'58D'59D'60D'61D'62D'63321111111133111111113411111111351111111136111111113711111111381111111139111111114011111111SIST EN 300 979 V6.0.1:2003
ETSIEN 300 979 V6.0.1 (1999-09)11(GSM 08.61 version 6.0.1 Release 1997)5.1.3O&M frameBit numberOctet no.1234567810000000020000000031C1C2C3C4C5C6C74C8C9C10C11C12C13C14C1551D1D2D3D4D5D6D76D8D9D10D11D12D13D14D1571D16D17D18D19D20D21D228D23D24D25D26D27D28D29D3091D31D32D33D34D35D36D3710D38D39D40D41D42D43D44D45111D46D47D48D49D50D51D5212D53D54D55D56D57D58D59D60131D61D62D63D64D65D66D6714D68D69D70D71D72D73D74D75151D76D77D78D79D80D81D8216D83D84D85D86D87D88D89D90171D91D92D93D94D95D96D9718D98D99D100D101D102D103D104D105191D106D107D108D109D110D111D11220D113D114D115D116D117D118D119D120211D121D122D123D124D125D126D12722D128D129D130D131D132D133D134D135231D136D137D138D139D140D141D14224D143D144D145D146D147D148D149D150251D151D152D153D154D155D156D15726D158D159D160D161D162D163D164D165271D166D167D168D169D170D171D17228D173D174D175D176D177D178D179D180291D181D182D183D184D185D186D18730D188D189D190D191D192D193D194D195311D196D197D198D199D200D201D20232D203D204D205D206D207D208D209D210331D211D212D213D214D215D216D21734D218D219D220D221D222D223D224D225351D226D227D228D229D230D231D23236D233D234D235D236D237D238D239D240371D241D242D243D244D245D246D24738D248D249D250D251D252D253D254D255391D256D257D258D259D260D261D26240D263D264S1S2S3S4S5S65.1.4CodingIn the following sections, the coding of the frames is described. Any spare or not used control bits should be codedbinary "1".5.1.4.1Coding of speech framesControl bits (C-bits):SIST EN 300 979 V6.0.1:2003
ETSIEN 300 979 V6.0.1 (1999-09)12(GSM 08.61 version 6.0.1 Release 1997)DescriptionUplinkDownlinkFrame type(Bits C1 - C4)C1 C2 C3 C4 0
1C1 C2 C3 C4 1
0Channel typeBit C51: half rate1: half rateTime Alignment(Bits C6 - C11)Binary number indicating therequired timing adjustment to bein steps of 250/500 µs.Binary number indicating the timingadjustment made.The following values apply for the codingC6C7 .
.
. C11 0
No change in frame timing 0
Delay frame 1 * 500 µs 0
Delay frame 2 * 500 µs
. . .
....
. . .
.... 1
Delay frame 39 * 500 µs 1
Not used
. . .
.... 1
Not used 1
Delay frame 1 * 250 µs 1
Advance frame 250 µsUplinkBad Frame Indicator (BFI)C12 (see GSM 06.41)DownlinkUplink Frame Error (UFE)C12 (see section 6.8.1.3)0: BFI = 01: BFI = 10: UFE = 0:bad uplink framing1: UFE = 1:good uplinkframingSilence Descriptor (SID)C13-C14(see GSM 06.41)C13C14: SIDSID1SID0
0: SID = 0
1: SID = 1
0: SID = 2Time Alignment Flag (TAF)C15(see GSM 06.41)0: TAF = 01: TAF = 1SpareSpeech indicator (SP)C16(see GSM 06.41)Spare0: SP = 01: SP = 1DTX downlink indicator (DTXd)C170: Downlink DTX shall not be applied1: Downlink DTX shall be appliedSpareBits C18 - C21SpareSpareUFI bit: Unreliable Frame Indication (see GSM 06.41).This bit is set to binary "1" in the downlink direction.Data Bits (D-bits)Bits D1 . D112:Speech block transferred in the same order as output from the transcoder (see GSM 06.20).Cyclic Redundancy Check bits (CRC-bits)Bits CRC0 . CRC2: CRC of the bits D1 to D44.The bits are coded according to a cyclic code using the generator polynomial:g(X) = X3+X+1The encoding of the cyclic code is performed in a systematic form, which means that, in GF(2), the polynomial:D1*X46 + D2*X45 + . + D44*X3 + CRC2*X2 + CRC1*X + CRC0.where CRC0, CRC1, CRC2 are the parity bits, when divided by g(X) yields a remainder equal to:1 + X + X2.SIST EN 300 979 V6.0.1:2003
ETSIEN 300 979 V6.0.1 (1999-09)13(GSM 08.61 version 6.0.1 Release 1997)Time Alignment BitsBits T1 . T4:Bits positioned at the end of the downlink and uplink TRAU speech frames.Downlink:If the timing of the frame is to be advanced 250 µs, these 4 bits are not transferred in order toreduce the frame length accordingly. When transferred, the bits are set to binary "1".Uplink:T1 and T2 are set to binary "1".If the timing of the frame is to be advanced 125 µs, the bits T3 and T4 are not transferred in orderto reduce the frame length accordingly. When transferred, the bits are set to binary "1" (seesection 6.6.1.1.2).5.1.4.2Coding of data framesAny spare or not used control bits should be coded binary "1".Control bits (C-bits):DescriptionUplinkDownlinkFrame typeBits C1-C4C1 C2 C3 C4 0
0: DataC1 C2 C3 C4 1
1: DataChannel typeBit C51: half rate1: half rateIntermediate RA bit rateBit C60: 8 kbit/s0: 8 kbit/sBits C7 - C11SpareSpareBit C12Uplink Frame Error (UFE)C12 (see section 6.8.1.3)Spare0: UFE = 0: bad uplink framing1: UFE = 1: good uplink framingBits C13-C15SpareSpareIdle data frameAn idle data frame is a data frame with all data bit positions set to binary "1" (i.e. all bits of the modified V.110 framesare set to "1").5.1.4.3Coding of O&M framesControl bits (C-bits):DescriptionUplinkDownlinkFrame typeBits C1-C4C1 C2 C3 C4 0
0: O&MC1 C2 C3 C4 1
1: O&MChannel typeBit C51: half rate1: half rateBits C6 - C11SpareSpareBit C12Uplink Frame Error (UFE)C12 (see section 6.8.1.3)Spare0: UFE = 0: bad uplink framing1: UFE = 1: good uplink framingBits C13-C15SpareSpareData Bits (D-bits)Bits D1 . D264:Bits used for transfer of O&M information. The coding and use of these bits are left to themanufacturer of the BSC/TRAU.Spare Bits (S-bits)Bits S1 . S6:Spare.SIST EN 300 979 V6.0.1:2003
ETSIEN 300 979 V6.0.1 (1999-09)14(GSM 08.61 version 6.0.1 Release 1997)5.28 kbit/s submultiplexing5.2.1Speech frameBit numberOctet no1234567810000000021C1C2C3C4C5XC1XC2301XC3XC4XC5XC6D1D241D3D4D5D6D7D8D951D10D11D12D13D14D15D1661D17D18D19D20D21D22D2371D24D25D26D27D28D29D3081D31D32D33D34D35D36D3791D38D39D40D41D42D43D44101CRC2CRC1CRC0D45D46D47D48111D49D50D51D52D53D54D55121D56D57D58D59D60D61D62131D63D64D65D66D67D68D69141D70D71D72D73D74D75D76151D77D78D79D80D81D82D83161D84D85D86D87D88D89D90171D91D92D93D94D95D96D97181D98D99D100D101D102D103D104191D105D106D107D108D109D110D111201D112C6C7C8C9T1T25.2.2Data frameBit numberOctet no.1234567810000000021C1C2C3C4C5D1D2301D3D4D5D6D7D841D9D10D11D12D13D14D1551D16D17D18D19D20D21D22Data frame61D23D24D25D26D27D28D29position 171D30D31D32D33D34D35D3681D37D38D39D40D41D42D4391D44D45D46D47D48D49D50101D51D52D53D54D55D56D57111D58D59D60D61D62D63D'1121D'2D'3D'4D'5D'6D'7D'8131D'9D'10D'11D'12D'13D'14D'15141D'16D'17D'18D'19D'20D'21D'22151D'23D'24D'25D'26D'27D'28D'29Data frame161D'30D'31D'32D'33D'34D'35D'36position 2171D'37D'38D'39D'40D'41D'42D'43181D'44D'45D'46D'47D'48D'49D'50191D'51D'52D'53D'54D'55D'56D'57201D'58D'59D'60D'61D'62D'631SIST EN 300 979 V6.0.1:2003
ETSIEN 300 979 V6.0.1 (1999-09)15(GSM 08.61 version 6.0.1 Release 1997)5.2.3O&M frameBit numberOctet no.1234567810000000021C1C2C3C4C5XC1XC2301XC3XC4XC5XC6D1D241D3D4D5D6D7D8D951D10D11D12D13D14D15D1661D17D18D19D20D21D22D2371D24D25D26D27D28D29D3081D31D32D33D34D35D36D3791D38D39D40D41D42D43D44101D45D46D47D48D49D50D51111D52D53D54D55D56D57D58121D59D60D61D62D63D64D65131D66D67D68D69D70D71D72141D73D74D75D76D77D78D79151D80D81D82D83D84D85D86161D87D88D89D90D91D92D93171D94D95D96D97D98D99D100181D101D102D103D104D105D106D107191D108D109D110D111D112D113D114201D115D116D117D118D119D12015.2.4CodingIn the following sections, the coding of the frames is described. Any spare or not used transmitted control bits should becoded binary "1".5.2.4.1Uplink codingControl bits (C-bits, for all frame types)The control bits are coded according to the following table:C1C2C3C4C5Meaning0001OPSpeech frame0011OPData frame0101OPO&M frameAll other codings are reserved.OP: odd parity of bits C1 to C4.In the following, the term "frame type" refers to the control bits C1 to C3.C6C7C8C9MeaningTA2TA1TA0DTXdFor speech frame onlyDTXd: DTX downlink indicator.0: Downlink DTX shall not be applied.1: Downlink DTX shall be applied.TA2-TA0: Time Alignment Command, see section 6.6.1.2.1.SIST EN 300 979 V6.0.1:2003
ETSIEN 300 979 V6.0.1 (1999-09)16(GSM 08.61 version 6.0.1 Release 1997)Extended control bitsThe extended control bits are coded according to the following table:Speech framesXC1XC2XC3XC4XC5XC6Meaning00000OPGood speech frame with UFI = 0(BFI=0, SID=0, TAF=1)(BFI=0, SID=0, TAF=0)00001OPUnreliable speech frame (if speech decoder is in speech decoding mode)or unusable frame (if speech decoder is in comfort noise insertion mode)with UFI = 1(BFI=0, SID=0, TAF=1)(BFI=0, SID=0, TAF=0)00010OPValid SID frame with UFI = 0(BFI=0, SID=2, TAF=1)(BFI=0, SID=2, TAF=0)00011OPInvalid SID frame with UFI = 1(BFI=0, SID=2, TAF=1)(BFI=0, SID=2, TAF=0)01000OPInvalid SID frame at TAF=0 with UFI = 0(BFI=0, SID=1, TAF=0)(BFI=1, SID=1, TAF=0)(BFI=1, SID=2, TAF=0)01001OPInvalid SID frame at TAF=0 with UFI = 1(BFI=0, SID=1, TAF=0)(BFI=1, SID=1, TAF=0)(BFI=1, SID=2, TAF=0)01010OPInvalid SID frame at TAF=1 with UFI = 0(BFI=0, SID=1, TAF=1)(BFI=1, SID=1, TAF=1)(BFI=1, SID=2, TAF=1)01011OPInvalid SID frame at TAF=1 with UFI = 1(BFI=0, SID=1, TAF=1)(BFI=1, SID=1, TAF=1)(BFI=1, SID=2, TAF=1)01100OPBad speech frame or unusable frame at TAF = 0 with UFI = 0(BFI=1, SID=0, TAF=0)01101OPBad speech frame or unusable frame at TAF = 0 with UFI = 1(BFI=1, SID=0, TAF=0)01110OPBad speech frame or unusable frame at TAF = 1 with UFI = 0(BFI=1, SID=0, TAF=1)01111OPBad speech frame or unusable frame at TAF = 1 with UFI = 1(BFI=1, SID=0, TAF=1)O&M frameXC1XC2XC3XC4XC5XC6Meaning11111OPO&M frameAll other codings are reserved.OP:odd parity of bits XC1 to XC5.BFI, SID, TAF:see description in section 5.1.4.1.UFI bit:Unreliable Frame Indication (see GSM 06.41).Cyclic Redundancy Check bits (CRC-bits)Speech frame: Bits CRC0 . CRC2: CRC of the bits D1 to D44. Same coding as in section 5.1.4.1.SIST EN 300 979 V6.0.1:2003
ETSIEN 300 979 V6.0.1 (1999-09)17(GSM 08.61 version 6.0.1 Release 1997)Data bits (D-bits)Speech frame: Bits D1 . D112:For good speech frame: speech block transferred in the same order as output from the transcoder(see GSM 06.20).For valid SID frame: SID data block transferred in the same order as output from the transcoder(see GSM 06.22).Data frame:Bits D1 . D63 for data frame position 1 and bits D'1 . D'63 for data frame position 2 (seesection 6.7.1).O&M frame: Bits D1 . D120: Bits used for transfer of O&M information. The coding and use of these bits areleft to the manufacturer of the BSC/TRAU.Time Alignment bits (T-bits)Bits T1.T2:Bits positioned at the end of the uplink TRAU speech frame.T1 is set to binary "1".If the timing of the frame is to be advanced 125 µs , the bit T2 is not transferred in order to reducethe frame length accordingly. When transferred, the bit T2 is set to binary "1".5.2.4.2Downlink codingControl bitsC1C2C3C4C5Meaning000UFEOPSpeech frame001UFEOPData frame010UFEOPO&M frameAll other codings are reserved.UFE: Uplink Frame Error.UFE = 0: bad uplink framing.UFE = 1: good uplink framing.See section 6.8.2.2.OP:Odd parity of bits C1 to C4.In the following, the term "frame type" refers to the control bits C1 to C3.C6C7C8C9Meaning1111Spare bitsExtended control bitsThe extended control bits are coded according to the following table:Speech framesXC1XC2XC3XC4XC5XC6Meaning00000OPGood speech frame (SP = 1)00010OPValid SID frame (SP = 0)SP:Speech indicator (see GSM 06.41).O&M frameXC1XC2XC3XC4XC5XC6Meaning11111OPO&MAll other codings are reserved.SIST EN 300 979 V6.0.1:2003
ETSIEN 300 979 V6.0.1 (1999-09)18(GSM 08.61 version 6.0.1 Release 1997)XC6:odd parity of bits XC1 to XC5.Data bits (D-bits)Same as the uplink.Time Alignment bits (T-bits)Bits T1.T2:Bits positioned at the end of the downlink TRAU speech frame.If the timing of the frame is to be advanced 250 µs, the bits T1 and T2 are not transferred in order toreduce the frame length accordingly. When transferred, the bits are set to binary "1" (seesection 6.6.1.2.1).Cyclic Redundancy Check bits (CRC-bits):Same as the uplink.5.3Order of Bit TransmissionThe order of bit transmission is:Bit m of octet n shall be transmitted as bit ((n-1)*8+m) with m=(1.8) and n=(1.20).6Procedures6.1Remote Control of Transcoders and Rate AdaptorsWhen the TRAU is positioned remote from the BTS, the CCU in the BTS has to control some of the functions in theremote TRAU.This remote control is performed by in-band signalling carried by the control bits in each TRAU frame.The following functions in the TRAU are remotely controlled by the CCU:-Change between speech and data;-Downlink frame timing for speech frames;-Transfer of DTX information.In addition, the in-band signalling also provides means for transfer of O&M signals between the TRAU and theBSC/BTS.6.2Resource AllocationAt reception of the GSM 08.08 ASSIGNMENT REQUEST message, e.g. at call setup, when a circuit switchedconnection is required, the BSC provides an appropriate TRAU to the circuit to be used between the BSC and the BTSand sends the GSM 08.58 CHANNEL ACTIVATION message to the BTS.When receiving the CHANNEL ACTIVATION message, the BTS allocates the appropriate radio resources and a CCUto be used.The CCU now starts sending uplink TRAU frames with the appropriate frame type.When receiving the first frame, the TRAU sets the mode of operation as indicated by the CCU and starts sendingdownlink TRAU frames with the corresponding frame type.SIST EN 300 979 V6.0.1:2003
ETSIEN 300 979 V6.0.1 (1999-09)19(GSM 08.61 version 6.0.1 Release 1997)6.3Resource ReleaseAt release of circuit switched resources, e.g. at call release, the connection between the CCU and the TRAU will bereleased by the BSC. The BSC has to indicate that the connection has been released. How this is performed is a BSCinternal matter. Two methods may be used for either submultiplexing scheme.i)The BSC indicates the call release to the TRAU by inserting the PCM idle bit pattern described in GSM 08.54 onthe circuits towards the TRAU. The TRAU shall be able to detect this idle bit pattern. When received at theTRAU, the TRAU will loose frame synchronization and will start timer Trelease = 1 second. If, when Treleaseexpires, the idle bit pattern is detected, the TRAU shall terminate the operation (go idle) until a valid frame isagain received. Trelease is reset every time the frame synchronization is again obtained.ii)It is handled by BSC internal signals (e.g. if the BSC and TRAU are collocated).6.4In Call ModificationAt reception of the GSM 08.58 MODE MODIFY message from the BSC indicating a change between speech and data,the BTS orders the corresponding CCU to modify its mode of operation. The CCU sets the frame type in the uplinkTRAU frames to the new mode of operation.When the TRAU receives an uplink TRAU frame with the frame type, different from the current mode but withouterrors detected (see section 6.9.1.2), the current mode is kept and speech/data bits are handled as erroneous. Whenreceiving the next TRAU frame with the same frame type, the TRAU changes the mode of operation accordingly andsets the new frame type in the downlink frames.6.5Handling of missing dataIf no speech is received from the MS (uplink direction), the CCU shall send TRAU speech frames with BFI flag set to 1(bad frame). If no data is received from the MS (uplink direction), the CCU shall send idle TRAU data frames.For speech calls, the CCU shall transmit a speech frame with the three parity bits inverted (protection of the mostsignificant 22 class 1 bits, see GSM 05.03) on the air interface:-if frame synchronization has been lost in the downlink direction;-if a CRC error is detected (bits CRC0-CRC2) in a downlink TRAU speech frame;-if an O&M TRAU frame is received (see section 6.10).For data calls, the CCU shall react towards the air interface as if an idle TRAU data frame has been received:-when frame synchronization has been lost in the downlink direction;-when an O&M TRAU frame is received (see section 6.10).An idle TRAU data frame is a TRAU data frame with all data bits set to binary "1".SIST EN 300 979 V6.0.1:2003
ETSIEN 300 979 V6.0.1 (1999-09)20(GSM 08.61 version 6.0.1 Release 1997)6.6Procedures for Speech Frames6.6.1Time Alignment of Speech FramesThe time alignment needed for obtaining minimum buffer delay will differ from call to call. The reasons for this are:-The BSC will have no information about the radio timing at the BTS, and will start sending TRAU frames at anarbitrary or default time. In the case of 16 kbit/s submultiplexing, each TRAU frame is 320 bits (20 ms) and willin the worst case be received at the BTS 318 bits out of phase. In the case of 8 kbit/s submultiplexing, eachTRAU frame is 160 bits (20 ms) and will in the worst case be received at the BTS 159 bits out of phase.-The different timeslots and half rate subchannels on one carrier are sent at different times (max. 8.66 ms whichequals 15 radio time slots).-Different channels may be transferred on different transmission systems using different routes in the network.The transmission delay may therefore differ.The required time alignment procedure between radio frames and TRAU frames is specified in sections 6.6.1.1 and6.6.1.2 for the 16 kbit/s submultiplexing and the 8 kbit/s submultiplexing respectively.In order to achieve optimum timing between the radio TDMA frames and the frames on the transmission side, thespeech coding and decoding function in the transcoder should not be synchronized.6.6.1.116 kbit/s submultiplexing6.6.1.1.1Downlink Time Alignment6.6.1.1.1.1Initial Time Alignment stateThe TRAU shall enter the Initial Time Alignment state at the switching-on of the system, when it goes idle (e.g. whenreceiving the PCM idle pattern after a call release as described in section 6.3), if loss of frame synchronization isdetected, in call modification from data to speech is performed or if BSS internal handover is detected.In the initial state, the frames shall only be delayed or no change is applied (see note below). The transcoder is able toadjust the time for transmitting the speech frames in steps of 125 µs (one speech sample). The CCU calculates therequired timing adjustment and returns a frame including the number of 250/500 µs steps by which the frames in thedownlink direction have to be delayed (binary number in the "Time Alignment" field).When receiving this information, the TRAU processes this data and sets the "Time Alignment" field in the nextdownlink frame as ordered and then delays the subsequent frame accordingly.If the TRAU, in this state, receives an order to advance the next frame 250 µs, this order shall be interpreted as "Delayframe 39*500 µs".When a frame is delayed due to timing adjustments, the TRAU shall fill in the gap between the frames with theappropriate number of binary "1".After having adjusted the timing, the TRAU shall receive at least three new frames before a new adjustment is made.This in order to avoid oscillation in the regulation.The TRAU shall change from the Initial Time Alignment state to the Static Time Alignment state when it has performedtwo subsequent timing adjustments which are less than 500 µs (including no change).The procedure is illustrated in figure 6.1.SIST EN 300 979 V6.0.1:2003
ETSIEN 300 979 V6.0.1 (1999-09)21(GSM 08.61 version 6.0.1 Release 1997)6.6.1.1.1.2Static Time Alignment stateIn the Static Time Alignment state, the TRAU performs timing adjustments in single steps of 250 µs. The timing mayeither be delayed (time alignment code 111110, advanced (time alignment code 111111) or not changed (time alignmentcode 000000).When receiving an order for adjusting the timing, the transcoder skips or repeats two speech samples in order to achievethe correct timing.If the timing is to be advanced 250 µs, the TRAU sets the "Time Alignment" field in the next downlink frame as orderedand then the 4 last bits of the frame are not transferred (the T-bits).If the timing is to be delayed, the TRAU sets the "Time Alignment" field in the next downlink frame as ordered and thendelays the subsequent frame by adding four binary "1" between the frames.After having adjusted the timing, the TRAU shall receive at least three new frames before a new adjustment is made.If, in this state, the TRAU detects a change in the timing of the uplink frames greater than 1ms, it shall enter the InitialTime Alignment state and in that state it may perform an adjustment on the downlink equal to the change detected on theuplink.SIST EN 300 979 V6.0.1:2003
ETSIEN 300 979 V6.0.1 (1999-09)22(GSM 08.61 version 6.0.1 Release 1997)MSCBSCBTSASSREQCHAN ACTIV Allocate andconnect TRAU
Allocate Radiochannel and CCU(L3
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