SIST EN 300 945 V7.0.3:2003

• Abstract:

  SUBJECT Synchronisation

• Status: Published
• Publication Date: 30-Nov-2003
• ICS: 33.070.50 - Global System for Mobile Communication (GSM)
• Technical Committee: SS EIT - Technical Board for the electrotechnical, information technology and telecommunications fields
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Dec-2003
• Due Date: 01-Dec-2003
• Completion Date: 01-Dec-2003
• Ref Project: ETSI EN 300 945 V7.0.3 (1999-12) - Digital cellular telecommunications system (Phase 2+) (GSM); Rate adaption on the Mobile Station - Base Station System (MS - BSS) Interface (GSM 04.21 version 7.0.3 Release 1998)

Overview

SIST EN 300 945 V7.0.3:2003 is the Slovenian implementation of the European standard EN 300 945, which specifies the rate adaptation functions for the interface between Mobile Stations (MS) and Base Station Systems (BSS) within the digital GSM cellular telecommunications system (Phase 2+). The standard, aligned with GSM 04.21 version 7.0.3 Release 1998, focuses on supporting the diverse data rate needs, ensuring proper synchronisation and compatibility across GSM networks for various bearer services.

Rate adaptation plays a critical role in mobile communications by enabling devices to efficiently convert terminal interface data rates to those required for transmission over GSM networks. This ensures seamless data transfer between terminals and network nodes, even when devices operate at different speeds or require different types of synchronisation.

Key Topics

• Rate Adaptation Functions: The standard defines a set of functions (RA0, RA1, RA1', RA1/RA1', RA1'', and RA2) to adapt terminal interface rates to MS-BSS interface requirements. Each function addresses specific scenarios such as conversion from asynchronous (e.g., serial ports) to synchronous data streams or from lower to higher bit rates.
• Data Rate Support: SIST EN 300 945 covers a range of supported user data rates, including single-slot and multislot configurations. Supported rates range from low-speed (≤600 bit/s) up to higher speeds (64 kbit/s), accommodating various GSM data services.
• Frame and Multiframe Structure: Specifies how user data, control, and synchronisation bits are structured in frames and multiframes for reliable transmission.
• Synchronisation: The scope emphasizes synchronisation of substreams in multislot operations, network-independent clocking, and compensation mechanisms to ensure timing coherence across the GSM network.
• Transparent and Non-transparent Services: Details adaptation for both service types, including padding, break signal handling, and support for both synchronous and asynchronous bearer services.
• Compliance with ITU-T V.110: Many adaptation mechanisms are harmonized with recommendations from ITU, ensuring international compatibility.

Applications

SIST EN 300 945 V7.0.3:2003 has practical value in the following areas:

• GSM Device Engineering: Developers of GSM mobile devices, base stations, and network elements rely on these specifications for designing data handling functions that are interoperable with GSM networks worldwide.
• Network Infrastructure: Telecom operators implement the rate adaptation requirements in MSCs (Mobile Switching Centres), BSSs, and related components to guarantee proper data flow between different network segments and user terminals.
• Mobile Data Services: Enables diverse services, such as high-speed circuit-switched data (HSCSD), SMS, fax, and internet access, by standardising data translation and synchronisation.
• Testing and Certification: Ensures that new equipment and software conform to GSM data interface requirements, enhancing network reliability and user experience.
• Interoperability: Facilitates cross-vendor and cross-border compatibility through adherence to a harmonised set of rate adaptation rules.

Related Standards

For comprehensive deployment and implementation, the following related GSM and telecommunications standards should be consulted:

• GSM 03.10 – GSM PLMN connection types (core overview of connection scenarios)
• GSM 08.20 – Rate adaptation on the BSS-MSC interface (complementary to the present document)
• GSM 05.03 – Channel coding
• GSM 07.01, 07.02, 07.03 – Terminal Adaptation Functions (TAF)
• EN 300 945 – European reference of the present standard
• ITU-T V.110/V.120 – International recommendations on rate adaptation for integrated services digital networks (ISDN)
• CCITT X.30 – Support of X.21 interfaces

These standards together provide a robust framework for synchronisation, rate adaptation, and seamless data interchange across multiple network technologies in the GSM ecosystem.

Keywords: GSM, rate adaptation, synchronisation, mobile station, base station system, interface, data rates, frame structure, network independent clocking, transparent services, non-transparent services, telecommunication standards, ITU-T V.110.

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Digital cellular telecommunications system (Phase 2+) (GSM); Rate adaption on the Mobile Station - Base Station System (MS - BSS) Interface (GSM 04.21 version 7.0.3 Release 1998)33.070.50Globalni sistem za mobilno telekomunikacijo (GSM)Global System for Mobile Communication (GSM)ICS:Ta slovenski standard je istoveten z:EN 300 945 Version 7.0.3SIST EN 300 945 V7.0.3:2003en01-december-2003SIST EN 300 945 V7.0.3:2003SLOVENSKI
STANDARD
ETSIEN300945V7.0.3(1999-12)EuropeanStandard(Telecommunicationsseries)Digitalcellulartelecommunicationssystem(Phase2+);RateadaptionontheMobileStation-BaseStationSystem(MS-BSS)Interface(GSM04.21version7.0.3Release1998)GLOBALSYSTEMFORMOBILECOMMUNICATIONSRSIST EN 300 945 V7.0.3:2003

ETSIETSIEN300945V7.0.3(1999-12)2(GSM04.21version7.0.3Release1998)ReferenceREN/SMG-040421Q7(8r003i20.PDF)KeywordsDigitalcellulartelecommunicationssystem,GlobalSystemforMobilecommunications(GSM)ETSIPostaladdressF-06921SophiaAntipolisCedex-FRANCEOfficeaddress650RoutedesLucioles-SophiaAntipolisValbonne-FRANCETel.:[phone]Fax:[phone]SiretN°34862356200017-NAF742CAssociationàbutnonlucratifenregistréeàlaSous-PréfecturedeGrasse(06)N°7803/[e-mail]ETSIdeliverablecanbedownloadedfromhttp://www.etsi.orgIfyoufinderrorsinthepresentdocument,sendyourcommentto:[e-mail]Ideliverablemaybemadeavailableinmorethanoneelectronicversionorinprint.Inanycaseofexistingorperceiveddifferenceincontentsbetweensuchversions,thereferenceversionisthePortableDocumentFormat(PDF).Incaseofdispute,thereferenceshouldbetheprintingonETSIprintersofthePDFversionkeptonaspecificnetworkdrivewithinETSISecretariat.CopyrightNotificationNopartmaybereproducedexceptasauthorizedbywrittenpermission.Thecopyrightandtheforegoingrestrictionextendtoreproductioninallmedia.©EuropeanTelecommunicationsStandardsInstitute1999.Allrightsreserved.SIST EN 300 945 V7.0.3:2003

ETSIETSIEN300945V7.0.3(1999-12)3(GSM04.21version7.0.3Release1998)ContentsIntellectualPropertyRights.5Foreword.51Scope.62References.62.1Abbreviationsanddefinitions.73Generalapproach.73.1Overviewofdataratesandconfigurations.74TheRA0Function.104.1Asynchronous-to-SynchronousConversion(RA0).104.2Breaksignal.104.3Overspeed/Underspeed.104.4ParityBits.104.5FlowControl.115TheRA1Function.115.1Adaptationofsynchronousdataratesupto38,4kbit/s.115.1.1NetworkIndependentClocking.125.1.1.1MultiframeStructure.125.1.1.2Encodingandcompensation.126TheRA1''function.136.1Rateadaptationof48kbit/suserrateswithDTE/DCEstatusto64kbit/s.136.2Rateadaptationof56kbit/suserrateto64kbit/s.137TheRA2Function.148TheRA1/RA1'Function.148.1Singleslotrates.148.1.1Radiointerfacerateof14,5kbit/s.158.1.1.1Multiframestructureovertheradio-interface.158.1.1.2Radio-interfacedatablockforTCH/F14.4channelcoding.178.1.2RadioInterfacerateof12kbit/s.178.1.4RadioInterfacerateof6kbit/s.188.1.5RadioInterfacerateof3,6kbit/s(transparentservicesonly).198.1.6Synchronisation.198.1.7Idleframes.198.2Multislotrates.198.2.1TCH/F14.4multislotoperation.208.2.2AIURsupto38,4kbit/susingTCH/F9.6andTCH/F4.8channelcodings.208.2.3AIURsupto38,4kbit/susingTCH/F14.4channelcoding.208.2.4AIURof48kbit/s;Intermediaterateof64kbit/s;Radiointerfacerateof5x12kbit/s.218.2.5AIURof48kbit/s;Intermediaterateof64kbit/s;Radiointerfacerateof4x14,5kbit/s.218.2.6AIURof56kbit/s;Intermediaterateof64kbit/s;.218.2.7AIURof56kbit/s;Intermediaterateof64kbit/s;Radiointerfacerateof4x14,5kbit/s.228.2.8AIURof64kbit/s;Radiointerfacerateof6x12kbit/s.228.2.9AIURof64kbit/s;Radiointerfacerateof5x14,5kbit/s.229TheRA1'Function.229.1Synchronoususerratesupto9,6kbit/s.239.2Synchronoususerratesfrom9,6kbit/sonward;TCH/F9.6/4.8channelcodings.239.3Synchronoususerratesfrom9,6kbit/sonward;TCH/F14.4channelcoding.2310TheSplit/CombineandPadding-functions.2410.1Dataframedistributionintothesubstreams/channelsbytheSplit/Combinefunction.2410.1.1Dataframedistributionintothesubstreams/channelsbytheSplit/Combinefunction(TCH/F9.6andTCH/F4.8channelcodings).24SIST EN 300 945 V7.0.3:2003

ETSIETSIEN300945V7.0.3(1999-12)4(GSM04.21version7.0.3Release1998)10.1.2DatablockdistributionintothesubstreamsbytheSplit/Combinefunction(TCH/F14.4channelcoding).2410.2Substreamnumberingintransparentoperation.2510.2.1SubstreamnumberingforTCH/F14.4channelcoding.2510.3SubstreamSynchronisation.2610.4Networkindependentclocking.2610.4.1NetworkIndependentClockingforTCH/F14.4channelcoding(bothsingle-andmultilinks).2610.4.1.1Negativecompensation.2610.4.1.2Positivecompensation.2610.5PaddingTCH/FframeswhentheAIURisnotamultipleof9,6or4,8kbit/s.2710.5.1PaddingforTCH/F14.4channelcoding.2711SupportofNon-TransparentBearerServices.2711.1Supportofnon-transparentoperationforTCH/F9.6andTCH/F4.8channelcodings.2711.2Supportofnon-transparentoperationforTCH/F14.4channelcoding.2812FiguresonFramestructures.28AnnexA(informative):Stacksofrateadaptation.33A.1Stacksofrateadaptationfor9,6/4,8kbit/ssingleslotoperation.33A.2Stacksofrateadaptationfor14,4kbit/ssingleslotoperation.34A.3Stacksofrateadaptationfor9,6/4,8kbit/smultislotoperation.36A.4Stacksofrateadaptationfor14,4kbit/smultislotoperation.37AnnexB(informative):AnexampleofmappingNetworkIndependentClockinginformationforTCH/F14.4whentheS-interfaceisdeployed:.39AnnexC(informative):Changehistory.40History.41SIST EN 300 945 V7.0.3:2003

ETSIETSIEN300945V7.0.3(1999-12)5(GSM04.21version7.0.3Release1998)IntellectualPropertyRightsIPRsessentialorpotentiallyessentialtothepresentdocumentmayhavebeendeclaredtoETSI.TheinformationpertainingtotheseessentialIPRs,ifany,ispubliclyavailableforETSImembersandnon-members,andcanbefoundinSR000314:"IntellectualPropertyRights(IPRs);Essential,orpotentiallyEssential,IPRsnotifiedtoETSIinrespectofETSIstandards",whichisavailablefromtheETSISecretariat.LatestupdatesareavailableontheETSIWebserver(http://www.etsi.org/ipr).PursuanttotheETSIIPRPolicy,noinvestigation,includingIPRsearches,hasbeencarriedoutbyETSI.NoguaranteecanbegivenastotheexistenceofotherIPRsnotreferencedinSR000314(ortheupdatesontheETSIWebserver)whichare,ormaybe,ormaybecome,essentialtothepresentdocument.ForewordThisEuropeanStandard(Telecommunicationsseries)hasbeenproducedbyTechnicalCommitteeSpecialMobileGroup(SMG).ThepresentdocumentdefinestherateadaptationfunctionstobeusedinMobileStations(MS)foradaptingterminalinterfacedataratestotheMobileStation-BaseStationSystem(MS-BSS)interfacedatarateswithinthedigitalcellulartelecommunicationssystem.ThecontentsofthepresentdocumentissubjecttocontinuingworkwithinSMGandmaychangefollowingformalSMGapproval.ShouldSMGmodifythecontentsofthepresentdocument,itwillbere-releasedbySMGwithanidentifyingchangeofreleasedateandanincreaseinversionnumberasfollows:Version7.x.ywhere:7IndicatesGSMPhase2+Release1998;xtheseconddigitisincrementedfortechnicalenhancements,corrections,updates,etcythethirddigitisincrementedwheneditorialonlychangeshavebeenincorporatedinthespecification;NationaltranspositiondatesDateofadoptionofthisEN:3December1999DateoflatestannouncementofthisEN(doa):31March2000DateoflatestpublicationofnewNationalStandardorendorsementofthisEN(dop/e):30September2000DateofwithdrawalofanyconflictingNationalStandard(dow):30September2000SIST EN 300 945 V7.0.3:2003

ETSIETSIEN300945V7.0.3(1999-12)6(GSM04.21version7.0.3Release1998)1ScopeThepresentdocumentdefinestherateadaptationfunctionstobeusedinGSMPLMNMobileStations(MS)sforadaptingterminalinterfacedataratestotheMobileStation-BaseStationSystem(MS-BSS)interfacedataratesinaccordancewithGSM03.10[3].Theprovisionofthesefunctionswilldependontheservicesaparticularstationisdesignedtosupport.NOTE:ThepresentdocumentshouldbeconsideredtogetherwithGSM08.20[9](RateAdaptationontheBSS-MSCInterface)togiveacompletedescriptionofPLMNrateadaptation.2ReferencesThefollowingdocumentscontainprovisionswhich,throughreferenceinthistext,constituteprovisionsofthepresentdocument.•Referencesareeitherspecific(identifiedbydateofpublication,editionnumber,versionnumber,etc.)ornon-specific.•Foraspecificreference,subsequentrevisionsdonotapply.•Foranon-specificreference,thelatestversionapplies.•Anon-specificreferencetoanETSshallalsobetakentorefertolaterversionspublishedasanENwiththesamenumber.•ForthisRelease1998document,referencestoGSMdocumentsareforRelease1998versions(version7.x.y).[1]GSM01.04:"Digitalcellulartelecommunicationsystem(Phase2+);Abbreviationsandacronyms".[2]GSM02.34:"Digitalcellulartelecommunicationssystem(Phase2+);HighSpeedCircuitSwitchedData(HSCSD)-Stage1".[3]GSM03.10:"Digitalcellulartelecommunicationsystem(Phase2+);GSMPublicLandMobileNetwork(PLMN)connectiontypes".[4]GSM03.34:"Digitalcellulartelecommunicationssystem(Phase2+);HighSpeedCircuitSwitchedData(HSCSD)-Stage2ServiceDescription".[5]GSM05.03:"Digitalcellulartelecommunicationssystem(Phase2+);Channelcoding".[6]GSM07.01:"Digitalcellulartelecommunicationsystem(Phase2+);GeneralonTerminalAdaptationFunctions(TAF)forMobileStations(MS)".[7]GSM07.02:"Digitalcellulartelecommunicationssystem(Phase2+);TerminalAdaptationFunctions(TAF)forservicesusingasynchronousbearercapabilities".[8]GSM07.03:"Digitalcellulartelecommunicationssystem(Phase2+);TerminalAdaptationFunctions(TAF)forservicesusingsynchronousbearercapabilities".[9]GSM08.20:"Digitalcellulartelecommunicationsystem(Phase2+);RateadaptionontheBaseStationSystem-Mobile-servicesSwitchingCentre(BSS-MSC)interface".[10]CCITTRecommendationV.110:"Supportofdataterminalequipments(DTEs)withV-Seriesinterfacesbyanintegratedservicesdigitalnetwork".[11]CCITTRecommendationX.30:"SupportofX.21,X.21bisandX.20bisbasedterminalequipments(DTEs)byintegratedservicesdigitalnetwork(ISDN)".SIST EN 300 945 V7.0.3:2003

ETSIETSIEN300945V7.0.3(1999-12)7(GSM04.21version7.0.3Release1998)2.1AbbreviationsanddefinitionsAbbreviationsusedinthepresentdocumentarelistedinGSM01.04.Overalldatastream:Thedatastreaminthosepartsofthenetworkwherethedataflowisnotsplitintomultiplechannels.Substream:Streamofdatawithexplicitorimplicitnumberingbetweensplitterandcombinerfunctions.Channel:Aphysicalfullratechannelontheradiointerface(TCH/F)independentofthecontentsMultislotintermediaterate:Intermediateratepersubstreaminthosepartsofthenetworkwheretheoveralldatastreamissplitintosubstreams.Intermediaterate:Intermediaterateintheoveralldatastream.Substreamrate:Theuserrateincludingpadding,ifapplicable,ononeindividualsubstream.3GeneralapproachGSM03.10definesthePLMNconnectiontypesnecessarytosupporttheGSMPLMNdataandtelematicservices.WithintheMSthereareseveraldifferentdatarateadaptationfunctions-andaSplit/Combine-functionincaseofamultislotdataconfiguration-whicharecombinedasshowninGSM03.10aspartoftheconnectiontype.TherateadaptationfunctionsareRA0,RA1,RA2,RA1',RA1''andRA1/RA1'.TheRA0,RA1andRA2areequivalenttothosefunctionsdescribedinCCITTrecommendationV.110[11].TheRA1'functionissimilartoRA1buthasareducedbitrateoutputcompatiblewiththecodingschemeproposedfordataservicesontheradiointerface.TheRA1''functionisusedforconvertingbetweensynchronoususerratesof48and56kbit/sandtherate64kbit/s.TheequivalentfunctioninCCITTrecommendationV.110doesnothaveaname.TheRA1/RA1'isarelayfunction,usedasindicatedinGSM03.10.Inmultislotdata-configurationstheoveralldatastreamissplitintoparallelsubstreamsbetweentheSplit/Combine-functions.3.1OverviewofdataratesandconfigurationsInTable1,anoverviewofthesupportedtransparentair-interfaceuserratesisgiven.Foreachrate,alsointermediateratesperchannelbetweenBTSandMSC,overallradiointerfacerates,andchannelconfigurationsaregiven.Forsingleslotconnectionstheintermediateratesareperchannelcarryingtheoveralldatastream,whereasformultislotconnections,theintermediateratesarepersubstream.InTable2,intermediaterateswithintheMS,overallradiointerfacerates,andchannelconfigurationsaregivenfortheair-interfaceuserrates.Theintermediateratesareperoveralldatastream.Forsingleslotratesupto4,8kbit/s,theusedintermediaterateis8kbit/s,andforthe9,6kbit/ssingleslotrate16kbit/s.ForTCH/F9.6andTCH/F4.8channelcodings,themultislotintermediateratesare16and8kbit/sperTCH/F,respectively.ForTCH/F14.4channelcoding,themultislotintermediaterateis16kbit/sperTCH/F.BetweentheTEandtheSplit/Combine-functionattheMS,wheretheoveralldatastreamisnotsplit,intermediateratesof8,16,32and64kbit/sareapplicableSIST EN 300 945 V7.0.3:2003

ETSIETSIEN300945V7.0.3(1999-12)8(GSM04.21version7.0.3Release1998)Table1:AIUR/MultislotintermediateratesAirinterfaceuserrateDTE/DCEstatusesRA0RA1'/RA1RA1'/RAA'RA1'MultislotintermediaterateFrametypeRadiointerfaceratePadding≤600bit/sXX8kbit/s80bitframes3,6kbit/s1200bit/sXX8kbit/s80bitframes3,6kbit/s2,4kbit/sXX8kbit/s80bitframes3,6kbit/s4,8kbit/sXX8kbit/s80bitframes6kbit/s9,6kbit/sXX16kbit/sor2×8kbit/s80bitframes12kbit/sor2×6kbit/s14,4kbit/sXX2×16kbit/sor3×8kbit/s80bitframes2×12kbit/sor3×6kbit/sP(note1)16kbit/sNote7Note814,5kbit/s19,2kbit/sXX2×16kbit/sor4×8kbit/s80bitframes2×12kbit/sor4×6kbit/s28,8kbit/sXX3×16kbit/s80bitframes3×12kbit/s2x16kbit/sNote7Note82×14,5kbit/s38,4kbit/sXX4×16kbit/s80bitframes4×12kbit/sP(note6)3x16kbit/sNote7Note83×14,5kbit/s48kbit/sXNote2Note25×12kbit/sP(note6)4x16kbit/sNote7Note84×14,5kbit/s56kbit/sNote2Note25×12kbit/s(note3)P(note6)4x16kbit/sNote7Note84×14,5kbit/s64kbit/sNote2Note26×12kbit/s(note3)P(note1)5×14,5kbit/s(note6)P=PaddingusedSIST EN 300 945 V7.0.3:2003

ETSIETSIEN300945V7.0.3(1999-12)9(GSM04.21version7.0.3Release1998)Table2:AIUR/IntermediateratesAirinterfaceuserrateDTE/DCEstatusesRA0RA1RA1'IntermediaterateFrametypeRadiointerfaceratePadding≤600bit/sXX8kbit/s80bitframes3,6kbit/s1200bit/sXX8kbit/s80bitframes3,6kbit/s2,4kbit/sXX8kbit/s80bitframes3,6kbit/s4,8kbit/sXX8kbit/s80bitframes6kbit/s9,6kbit/sXX16kbit/s80bitframes12kbit/sor2×6kbit/s14,4kbit/sXX32kbit/s80bitframes2×12kbit/sor3×6kbit/s1x14,5kbit/sP(note1)19,2kbit/sXX32kbit/s80bitframes2×12kbit/sor4×6kbit/s28,8kbit/sXX64kbit/s80bitframes3×12kbit/s2×14,5kbit/s38,4kbit/sXX64kbit/s80bitframes4×12kbit/s3×14,5kbit/sP(note6)48kbit/sXNote4Note45×12kbit/s4×14,5kbit/sP(note6)56kbit/sNote4Note45×12kbit/s(note3)4×14,5kbit/sP(note6)64kbit/sNote5Note56×12kbit/s(note3)5×14,5kbit/sP(note1)(note6)P=PaddingusedNOTE1:Forinformationonthepaddingprocedure,pleaserefertoclause10ofthepresentdocument.NOTE2:Nomultislotintermediaterate;substreamscombinedattheBSS.NOTE3:AIUR11,2kbit/sperchannelNOTE4:ForthisrateGSM-specificrateadaptationfunctionRA1''ratherthanRA1isapplied.NOTE5:ForthisrateRA1-andRA2-adaptationsarenotapplied.NOTE6:PaddingusedasspecifiedforTCH/F14.4channelcodingsNOTE7:Atthenetworkside,RA1'/RA1notapplied;insteadaTCH/F14,4-specificadaptationRA1'/RAA'used(GSM08.20)NOTE8:A320-bitframeformatdescribedinGSM08.60.SIST EN 300 945 V7.0.3:2003

ETSIETSIEN300945V7.0.3(1999-12)10(GSM04.21version7.0.3Release1998)4TheRA0Function4.1Asynchronous-to-SynchronousConversion(RA0)TheRA0Functionisonlyusedwithasynchronousinterfaces.Incomingasynchronousdataispaddedbytheadditionofstopelementstofitthesameornearesthighersynchronousratedefinedby2tothepowern(wheren≤6)times600bit/s,14,4kbit/sor28,8kbit/s.Thusboth75bit/sand300bit/suserdatasignallingratesshallbeadaptedtoasynchronous600bit/sstream.TheresultantsynchronousstreamisfedtoRA1orRA1'.TheRA0usedinGSMisnotidenticaltothatdescribedinITU-TRecommendationV.110whichconverts14,4and28,8kbit/suserratesto19,2and38,4kbit/s,respectively.AsynchronoususerrateSynchronoususerrate≤0.6kbit/s0.6kbit/s1,2kbit/s1,2kbit/s2,4kbit/s2,4kbit/s4,8kbit/s4,8kbit/s9,6kbit/s9,6kbit/s14,4kbit/s14,4kbit/s19,2kbit/s19,2kbit/s28,8kbit/s28,8kbit/s38,4kbit/s38,4kbit/s4.2BreaksignalTheRA0shalldetectandtransmitthebreaksignalinthefollowingfashion:Iftheconverterdetects2Mto2M+3bits,allofstartpolarity,whereMisthenumberofbitspercharacterintheselectedformatincludingstartandstopsbits,theconvertershalltransmit2M+3bitsofstartpolarity.Iftheconverterdetectsmorethan2M+3bitsallofstartpolarity,theconvertershalltransmitallthesebitsasstartpolarity.The2M+3ormorebitsofstartpolarityreceivedfromthetransmittingsidesshallbeoutputtothereceivingterminal.Theterminalmusttransmitoncircuit103atleast2Mbitsstoppolarityafterthestartpolaritybreaksignalbeforesendingfurtherdatacharacter.Theconvertershallthenregaincharactersynchronismfromthefollowingstoptostarttransition.4.3Overspeed/UnderspeedARA0shallinsertadditionalstopelementswhenitsassociatedterminalistransmittingwithalowerthannominalcharacterrate.Iftheterminalistransmittingcharacterswithanoverspeedofupto1%,theasynchronous-to-synchronousconvertermaydeletestopelementsasoftenasisnecessarytoamaximumofoneforeveryeightcharactersat1%overspeed.Theconverteronthereceivingsideshalldetectthedeletedstopelementsandreinserttheminthereceiveddatastream(circuit104).Therealizationofoverspeedhandling,asdescribedabove,attheinterfacetotheassociatedterminalisimplementationdependent.Possibleimplementationsaree.g.thereductionofthelengthofthestopelementsaccordingtoV.110[9]orincreaseddataratesbetweentheTAandterminal.4.4ParityBitsPossibleparitybitsincludedintheuserdataareconsideredasdatabitsbytheRA0function(andRA1function).SIST EN 300 945 V7.0.3:2003

ETSIETSIEN300945V7.0.3(1999-12)11(GSM04.21version7.0.3Release1998)4.5FlowControlWhereapplicable,thisfunctionisasspecifiedintherelevantterminaladaptationfunctionSpecification(seeGSM07series).5TheRA1FunctionThisfunctionisusedtoadaptbetweenthesynchronoususerrates,ortheoutputoftheRA0functionandtheintermediaterateof8,16,32or64kbit/s.5.1Adaptationofsynchronousdataratesupto38,4kbit/sSynchronoususerrateIntermediaterate≤2,4kbit/s8kbit/s4,8kbit/s8kbit/s9,6kbit/s16kbit/s14,4kbit/s32kbit/s19,2kbit/s32kbit/s28,8kbit/s64kbit/s38,4kbit/s64kbit/sACCITTV.11080bitsframeisconstructedusingtheuserdatabitsreceived(fromtheRA0intheasynchronouscase),thevaluesoftheSbitsarededucedfromtheRinterface.Adaptationof600bit/sto8Kbit/sisperformedby8timesconsecutiveduplicationofeachuserdatabit.(Figure9)Adaptationof1200bit/sto8Kbit/sisperformedby4timesconsecutiveduplicationofeachuserdatabit.(Figure8)Adaptationof2400bit/sto8kbit/sisperformedby2timesconsecutiveduplicationofeachuserdatabit.(Figure7)Adaptationof4800bit/sto8Kbit/sisperformedbytransmittingthebitstreamwithnoduplication.(Figure3)Adaptationof9600bit/sto16Kbit/sisperformedbytransmittingthebitstreamwithnoduplication(theemittingperiodishalvedwithrespecttothe4800bit/scase).(Figure3)Adaptationof14400bit/sto32Kbit/sisperformedasfor3600bit/sto8kbit/s(theemittingperiodisdividedbyfourwithrespecttothe3600bit/scase).(Adaptationof3600bit/sto8kbit/sisperformedbytransmittingthebitstreamwithnoduplication.)(Figure12)Adaptationof19200bit/sto32Kbit/sisperformedasfor4800bit/sto8kbit/s(theemittingperiodisdividedbyfourwithrespecttothe4800bit/scase).(Figure3)Adaptationof28800bit/sto64Kbit/sisperformedasfor3600bit/sto8kbit/s(theemittingperiodisdividedbyeightwithrespecttothe3600bit/scase).(Figure12)Adaptationof38400bit/sto64Kbit/sisperformedasfor4800bit/s8kbit/s(theemittingperiodisdividedbyeightwithrespecttothe4800bit/scase).(Figure3)TheCCITTV.11080bitframesshowninFigures3and12areused.TheDbitsareusedtoconveytheuserdataandtheSandXbitsareusedtoconveychannelcontrolinformationaccordingtoGSM07.01.SIST EN 300 945 V7.0.3:2003

ETSIETSIEN300945V7.0.3(1999-12)12(GSM04.21version7.0.3Release1998)TheEbitsareusedtoconveythefollowinginformation:i)UserDataRate-E1,E2,E3(forsingleslotoperationseeFigure4,andformultislotoperationFigure4andsubclause10.7)ii)NetworkIndependentClocking-E4,E5,E6iii)MultiframeSynchronisation-E7Theorderoftransmissionofthe80bitframeisfromlefttorightandtoptobottom.5.1.1NetworkIndependentClockingSynchronousdatasignalsreceivedbytheMTfromtheDTEattheMSorbyIWFfromthemodemonthePSTNmaynotbesynchronizedtothePLMN.ThefollowingmethodshallbeusedtoenabletransferofthosedatasignalsandthecorrespondingbittiminginformationviatheV.110frames.SuchasituationwouldexistwherethesignalsreceivedfromthemodemattheIWFrequireitsownclockorwherethesignalsreceivedfromtheDTEattheMSemploysitsownnetworkindependentclock.Inanycase,thefrequencytoleranceoftheclocksinvolvedis100ppm.5.1.1.1MultiframeStructureThetransmittingendoftheGSMPLMNconnectionshallestablishamultiframestructureutilizingbitE7consistingoffourframesbysettingE7ineveryfourthframetobinary0.ThisstructureisidenticaltotheuseofE7inV.110(andX.30)exceptthatsuchamultiframestructurewillexistforalluserdatarates.ThisframesynchronizationwillbeachievedandmaintainedduringtheentirecallsothatcorrectionsforthenetworkindependentclockingbythereceivingendoftheGSMPLMNconnectioncanbeeasilyrecognizedandappliedbasedonthecodewords(inc1,c2,c3,c4andc5)positionedinbitsE4,E5andE6oftwoconsecutiveV.110framesasillustratedinfigure1.Thus,themultiframestructureallowsforone5-bitcodewordstobetransmittedeverytwoV.110framesforthepurposesofnetworkindependentclocking.Thetwocode-wordsmaybedifferentfromeachotherwithinthemultiframeshowninfigure1.FrameE4E5E6E7MF0ac1c210MF1ac3c4c51MF0bc1c211MF1bc3c4c51Figure1:NICMultiframeStructureOnceMultiframesynchronizationisachieved,eachcodewordisindependentlyevaluatedtodeterminethecompensationneeded,ifany.Thecompensationisappliedasexplainedinsection3.1.2inV.110framesMF1aandMF1b.5.1.1.2EncodingandcompensationTheV.110transmitterwillusethefollowing5-bitcodewords,asshowninfigure2,toindicatethefourpossiblestatesofcompensationrequiredfornetworkindependentclocking.c1c2c3c4c5Nocompensation11111Negativecompensation10010Positivecompensationofazero01001Positivecompensationofone00100Figure2:NICCodeWordsWhennegativecompensationisindicated,onelessuserdatabitthannormalistransportedintheaffectedframe(MF1aorMF1b).AnegativecompensationshallcausethereceivertodeletetheuserdatabitoccupiedbybitpositionD25,sincethetransmittersetsthistobinary1anddoesnotutilizethispositionforuserdata.Atthoseuserdatarateswheretheuserdatabitisrepeated,allcopiesofD25shallbediscarded.Incaseof80-bitframeswith36databits,bitD19isdiscardedinstead.SIST EN 300 945 V7.0.3:2003

ETSIETSIEN300945V7.0.3(1999-12)13(GSM04.21version7.0.3Release1998)Whenapositivecompensationisindicated,oneadditionaluserdatabitistransferredbymeansofthecodeword.Atthereceiver,apositivecompensationwillcauseauserdatabitofbinaryvalue0or1,asindicatedbythecodeword,tobeinsertedbetweentheuserdatabitscarriedinbitpositionsD24andD25(inMF1aorMF1b)oftheV.110frameillustratedinfigure3.Incaseof80-bitframeswith36databits,theinsertionisdonetobetweenbitsD18andD19.Whennocompensationisnecessary,orwhenNICisapplied,thevaluesofE4,E5,E6,E7,onthe4multiframeschemeis:FrameE4E5E6E7MF0a1110MF1a1111MF0b1111MF1b1111WhenNICisnotapplicable,theMSandtheIWFshalldisregardthereceivedvalueofbitsE4,E5,E6andE7inthedatatransmissionphase.NOTE:NICisnotapplicableinthefollowingcases:-transparentasynchronousbearerservices;-thefacsimileteleservicesinthetransparentmode;-everytransparentbearerserviceswheninterworkingwithanUDIInformationTransferCapability.6TheRA1''functionTheRA1''functionisusedforconvertingbetweensynchronoususerratesof48and56kbit/sandthe'intermediate'rateof64kbit/s.(RA1''isaGSM-specifictermwhichisusedfortheone-stepadaptationof48and56kbit/sratesinto64kbit/sasspecifiedinITU-TV.110.ForthepurposesofGSMspecificationstheterm'intermediaterate'isusedfortheresulting64kbit/sratealthoughthisisnotdoneinV.110recommendation.)6.1Rateadaptationof48kbit/suserrateswithDTE/DCEstatusto64kbit/sACCITTV.11032bitsframeisconstructedusingtheuserdatabitsreceived,thevaluesoftheSbitsarededucedfromtheRinterface.TheCCITTV.11032bitframeshowninFigure13isused.TheDbitsareusedforconveyingtheuserdataandtheSandXbitsareusedforconveyingchannelcontrolinformationaccordingGSM07.01.Theorderoftransmissionofthe32bitframeisfromlefttorightandtoptobottom.6.2Rateadaptationof56kbit/suserrateto64kbit/sACCITTV.11064bitsframeisconstructedusingtheuserdatabitsreceived.TheCCITTV.11064bitframeshowninfigure14isused.TheDbitsareusedforconveyingtheuserdata.Theorderoftransmissionofthe64bitframeisfromlefttorightandtoptobottom.SIST EN 300 945 V7.0.3:2003

ETSIETSIEN300945V7.0.3(1999-12)14(GSM04.21version7.0.3Release1998)7TheRA2FunctionThisprocedureisbasedontheRA2functionasspecifiedinCCITTV.110.Itisusedtorateadaptto/fromtheintermediateratesof8,16or32kbit/sfrom/tothe64kbit/srateusedattheSinterface.IntermediaterateRateattheSinterface8kbit/s64kbit/s16kbit/s64kbit/s32kbit/s64kbit/s64kbit/s64kbit/sFortheintermediate-anduserdatarateof64kbit/s,theRA2transmitsthebitstreamovertheS-interfaceasitis.Itconsidersthe64kbit/sstreamovertheS-interfacetoconsistofoctets,bits1through8,withbit1beingtransmittedfirst.Theprocedurerequiresthat:i)The8kbit/sstreamoccupiesbitposition1;ii)The16kbit/sbitstreamoccupiesbitpositions(1,2);iii)The32kbit/sbitstreamoccupiesbitpositions(1,2,3,4);iv)Theorderoftransmissionofthebitsofthesubratestreamisidenticalbeforeandafterrateadaptation.v)Allunusedbitsinthe64kbit/sstreamaresettobinary"1".8TheRA1/RA1'FunctionTheRA1/RA1'functionisusedintransparentcasestoconvertbetweentheintermediaterateandtheinputratetothechannelcoderfunctionfortransmissionovertheradiointerface.Thisconversionalsoappearsontheinfrastructuresideinbothtransparentandnon-transparentcasesasspecifiedinGSM08.20exceptforTCH/F14.4.8.1SingleslotratesIntermediaterateRadiointerfacerate8kbit/s3,6kbit/s8kbit/s6kbit/s16kbit/s12kbit/s32kbit/s14,5kbit/sTherearefourdatarates(knownasRadioInterfacerates)usedfordatatransfertothechannelcoder.Theseare14,5kbit/s,12kbit/s,6kbit/sand3.6kbit/s,andinordertoadaptthe8,16,and32kbit/sintermediateratestothesedatarates,threeprocessesareused.Firstlythe17synchronizationbitsareremoved.SecondlytheE1,E2andE3bitsareremoved.Fortransparentservices,thevaluesoftheE1,E2,E3bitsaredeterminedattheMTandincaseofTCH/F9.6andTCH/F4.8,attheBTSbasedontheindicationgivenbyoutbandsignalling(eitherintheUserRatefieldoftheBC-IEoftheSETUPmessagefortheMTorintheChannelTypeinformationintheASSIGNMENTREQUESTmessagefortheBSS).Fornontransparentservices,thecodingoftheE1,E2andE3bitsisdescribedinGSM08.20.Thirdly,inthe3.6kbit/scase,halfthedatabitsarediscarded.TheseprocessesresultinmodifiedCCITTV.110framesofsizes60,60and36bitsforthe12,6and3.6kbit/sdataratesrespectively.TheresultantmodifiedCCITTV.110framesforthevarioususerdataratesareshowninfigures5-9.SIST EN 300 945 V7.0.3:2003

ETSIETSIEN300945V7.0.3(1999-12)15(GSM04.21version7.0.3Release1998)FurtherproceduresforTCH/F14.4channelcoderinputrateinsubclause8.1.1.8.1.1Radiointerfacerateof14,5kbit/sInthiscaseonemodifiedCCITTV.110frameisreceived/sentfrom/tothenetworkevery2.5ms(seeGSM05.03).TheRA1/RA1'functionadds/subtractsthe17-bitsynchronisationpattern,theF-,E-,X-,andS-bitsto/fromthe80-bitV.110-frames.BitsM1andM2aretransmittedalongwiththemodified36-bitV.110framesevery20msovertheradiointerface(SeeGSM05.03).BitM2isusedbytheRA1/RA1'-functionforderiving/mappingtheE-,S-,andX-bits.BitM1isusedformultislotsynchronisation.Theusageofthesebitsisfurtherelaboratedinsubclause8.1.1.1.ThemodifiedCCITTV.11036-bitframereceived/sentfrom/tothenetworkat14,4kbit/s:D1D2D3D4D5D6D7D8D9D10D11D12D13D14D15D16D17D18D19D20D21D22D23D24D25D26D27D28D29D30D31D32D33D34D35D36isconverted/derivedinto/fromthefollowing80-bitV.110-frameat32kbit/s.TheE-,S-,andX-bitsaremapped/extractedto/fromtheM2-bitsequence.000000001D1D2D3D4D5D6S11D7D8D9D10FFX1D11D12FFD13D14S31FFD15D16D17D18S41E1E2E3E4E5E6E71D19D20D21D22D23D24S61D25D26D27D28FFX1D29D30FFD31D32S81FFD33D34D35D36S9Forthe36-bitframesthereceivedD-bitsaresetastheyweretransmitted.FortransparentservicesE,S,andX-bitsarereproducedbasedontheM2-bitsequenceasdescribedinsubclause8.1.1.1.BitsE1,E2,andE3aresetaccordingtotheuserdatarateasshowninFigure4fortransparentservices.8.1.1.1Multiframestructureovertheradio-interfaceBitM1carriesa31-bitPNmultiframecode0000100101100111110001101110101.Onemultiframebitistransmittedevery20ms,whichmeansthatonewholemultiframeconsistsof24836-bit2.5msframes.BitM2carriesV.24circuitstatusinformation,networkindependentclocking(NIC)informationandsubstreamnumberingasindicatedinthefollowingfigure:bitnumber012345678-1112-1516-1920-2324-2728-30M1:0000100101100111110001101110101M2:###SBSBX###XSBSB###SBSBX###XSBSBNNNNNSBSBwhere###=Substreamnumber(multilinkoperation)SB=theSBstatusbitX=theX-statusbitNNNNN=NetworkindependentclockingcodeIntheMStoNetworkdirectiontheinformationcarriedbytheM2-bitsequenceismappedinthefollowingmanner:SIST EN 300 945 V7.0.3:2003

ETSIETSIEN300945V7.0.3(1999-12)16(GSM04.21version7.0.3Release1998)AnM1/M2-bitpairistransmittedalongeachblockofdatacontainingeightmodifiedV.11036-bitframes.Thethree-bit#-sequencecarriesanumberidentifyingeachsubstream(multislotoperation);thesubstreamsarenumbered0,1,2etc.Thestatus-andNIC-informationismappedbetweentheM2-sequence(s)andtheV.110-frames.BitsSBandXaremappedtoV.24circuitsasspecifiedinGSM07.01.TheSB-bitcarriestheV.110SB-statusinformation,andtheX-bittheX-statusinformation.FiveconsecutiveN-bitscarryinganNIC-codeintheM2-sequenceindicate'negativecompensation'or'positivecompensation'ifsuchacompensationisrequired.Otherwise'nocompensation'isindicatedbytheN-bits.N-bit24inM2-sequenceN-bit25inM2-sequenceN-bit26inM2-sequenceN-bit27inM2-sequenceN-bit28inM2-sequenceNocompensation11111Negativecompensation10010Positivecompensationofazero01001Positivecompensationofaone00100TheNetworktoMSdirection:Thestatus-informationisfilteredasdescribedinGSM07.01.TochangetheSB-orX-statusmode,itisrequiredthatatleasttwoconsecutiveSB-orX-bits,respectively,carrythesamevalue.ForNIC-procedure,refertosubclause10.5.1.SIST EN 300 945 V7.0.3:2003

ETSIETSIEN300945V7.0.3(1999-12)17(GSM04.21version7.0.3Release1998)8.1.1.2Radio-interfacedatablockforTCH/F14.4channelcodingAradio-interfacedatablockforaTCH/F14.4channelconsistsof836-bitdataframesandbitsM1andM2asshowninthefollowingtable:M1M21D1D2D3D4D5D6D7D8D9D10D11D12D13D14D15D16D17D18D19D20D21D22D23D24D25D26D27D28D29D30D31D32D33D34D35D362D1D2D3D4D5D6D7D8D9D10D11D12D13D14D15D16D17D18D19D20D21D22D23D24D25D26D27D28D29D30D31D32D33D34D35D363D1D2D3D4D5D6D7D8D9D10D11D12D13D14D15D16D17D18D19D20D21D22D23D24D25D26D27D28D29D30D31D32D33D34D35D364D1D2D3D4D5D6D7D8D9D10D11D12D13D14D15D16D17D18D19D20D21D22D23D24D25D26D27D28D29D30D31D32D33D34D35D365D1D2D3D4D5D6D7D8D9D10D11D12D13D14D15D16D17D18D19D20D21D22D23D24D25D26D27D28D29D30D31D32D33D34D35D366D1D2D3D4D5D6D7D8D9D10D11D12D13D14D15D16D17D18D19D20D21D22D23D24D25D26D27D28D29D30D31D32D33D34D35D367D1D2D3D4D5D6D7D8D9D10D11D12D13D14D15D16D17D18D19D20D21D22D23D24D25D26D27D28D29D30D31D32D33D34D35D368D1D2D3D4D5D6D7D8D9D10D11D12D13D14D15D16D17D18D19D20D21D22D23D24D25D26D27D28D29D30D31D32D33D34D35D36Thenumberontheleftindicatestheorderofthedataframesinthe290-bitblock;the36-bitframeinpositiononewasreceivedbeforethatinpositiontwoetc.Onesuchblockistransmittedovertheradiointerfaceevery20ms.8.1.2RadioInterfacerateof12kbit/sInthiscaseonemodifiedCCITTV.11060bitframeisreceived/sentfrom/tothenetworkevery5ms(seeGSM05.03).TheRA1/RA1'functionwilladd/subtractthe17bitsynchronizationpatternandtheE1,E2andE3bitsto/fromeachCCITTV.11080bitframeasfollows:ThemodifiedCCITTV.11060bitsframereceived/sentfrom/totheradiointerfaceat12Kbit/s,D1D2D3D4D5D6S1D7D8D9D10D11D12XD13D14D15D16D17D18S3D19D20D21D22D23D24S4E4E5E6E7D25D26D27D28D29D30S6D31D32D33D34D35D36XD37D38D39D40D41D42S8D43D44D45D46D47D48S9SIST EN 300 945 V7.0.3:2003

ETSIETSIEN300945V7.0.3(1999-12)18(GSM04.21version7.0.3Release1998)isconvertedintothefollowingaCCITTV.11080bitsframeat16Kbit/s:000000001D1D2D3D4D5D6S11D7D8D9D10D11D12X1D13D14D15D16D17D18S31D19D20D21D22D23D24S41E1E2E3E4E5E6E71D25D26D27D28D29D30S61D31D32D33D34D35D36X1D37D38D39D40D41D42S81D43D44D45D46D47D48S9Inthecaseofthenontransparentservices,bitsS1,X,S3,S4,E4,E5,E6,E7,S6,X(secondoccurrence),S8,andS9carrybitsD'1,D'2,D'3,D'4,D'5,D'6,D'7,D'8,D'9,D'10,D'11,andD'12,respectively.ForamodifiedCCITTV.11060bitframesreceivedfromthenetwork,thereceivedD,SandXbitsorDandD'bitsaresettothesamevalueasthetransmittedbits.BitsE1,E2,E3aresetaccordingtotheuserdatarateasshowninfigure4forthetransparentservices,ortheRLPmultiframeandDTXindicationasperGSM08.20inthenontransparentcase.FormodifiedCCITTV.11060bitframestransmittedoverthenetwork,thereceivedD,S,andXbitsorDandD'aresettothesamevalueasthetransmittedbits.BitsE1,E2,E3arediscarded.8.1.4RadioInterfacerateof6kbit/sInthiscaseonemodifiedCCITTV.11060bitframeisreceived/sentfrom/tothenetworkevery10ms(seeGSM05.03).TheRA1/RA1'functionwilladd/subtractthe17bitsynchronizationpatternandtheE1,E2andE3bitsto/fromeachCCITTV.11080bitframeasfollows:ThemodifiedCCITTV.11060bitsframereceived/sentfrom/totheradiointerfaceat6Kbit/s,D1D2D3D4D5D6S1D7D8D9D10D11D12XD13D14D15D16D17D18S3D19D20D21D22D23D24S4E4E5E6E7D25D26D27D28D29D30S6D31D32D33D34D35D36XD37D38D39D40D41D42S8D43D44D45D46D47D48S9isconvertedintothefollowingaCCITTV.11080bitsframeat8Kbit/s:000000001D1D2D3D4D5D6S11D7D8D9D10D11D12X1D13D14D15D16D17D18S31D19D20D21D22D23D24S41E1E2E3E4E5E6E71D25D26D27D28D29D30S61D31D32D33D34D35D36X1D37D38D39D40D41D42S81D43D44D45D46D47D48S9Inthecaseofthenontransparentservices,bitsS1,X,S3,S4,E4,E5,E6,E7,S6,X(secondoccurrence),S8,andS9carrybitsD'1,D'2,D'3,D'4,D'5,D'6,D'7,D'8,D'9,D'10,D'11,andD'12,respectively.SIST EN 300 945 V7.0.3:2003

ETSIETSIEN300945V7.0.3(1999-12)19(GSM04.21version7.0.3Release1998)ForamodifiedCCITTV.11060bitframesreceivedfromthenetwork,thereceivedD,SandXbitsorDandD'bitsaresettothesamevalueasthetransmittedbits.BitsE1,E2,E3aresetaccordingtotheuserdatarateasshowninfigure4forthetransparentservices,ortheRLPmultiframeandDTXindicationasperGSM08.20inthenontransparentcase.FormodifiedCCITTV.11060bitframestransmittedoverthenetwork,thereceivedD,S,andXbitsorDandD'bitsaresettothesamevalueasthetransmittedbits.BitsE1,E2,E3arediscarded.Itshouldbenotedthatthisprocessisidenticaltothatusedforthe12kbit/scaseexceptthattheframerepetitionratesarehalved.8.1.5RadioInterfacerateof3,6kbit/s(transparentservicesonly)InthiscaseonemodifiedCCITTV.11036bitframeisreceived/sentfrom/tothenetworkevery10ms(seeGSM05.03[3]).TheRA1/RA1'functionwilladd/subtractthe17bitsynchronizationpatternandtheE1,E2andE3bitsto/fromeachCCITTV.11080bitframeasfollows:ThemodifiedCCITTV.11036bitsframereceived/sentfrom/totheradiointerfaceat3.6Kbit/s,D1D2D3S1D4D5D6XD7D8D9S3D10D11D12S4E4E5E6E7D13D14D15S6D16D17D18XD19D20D21S8D22D23D24S9isconvertedintothefollowingaCCITTV.11080bitsframeat8Kbit/s:000000001D1D1D2D2D3D3S11D4D4D5D5D6D6X1D7D7D8D8D9D9S31D10D10D11D11D12D12S41E1E2E3E4E5E6E71D13D13D14D14D15D15S61D16D16D17D17D18D18X1D19D19D20D20D21D21S81D22D22D23D23D24D24S9FormodifiedCCITTV.11036bitframestransmittedtothenetwork,E1,E2,E3arediscarded.FormodifiedCCITTV.11036bitframesreceivedfromthenetwork,E1,E2,E3aresetasshowninfigure2.NOTE:Theactiontobetakeninthecasewheretwobitswhichshouldhavethesamevalue(e.g.bitsnotedD1arereceivedwithdifferentvaluesisforfurtherstudy.8.1.6SynchronisationTwointerfacesareinvolvedintheTAFregardingtheneedfordataframesynchronisation,i.e.theTAF/air-interfaceandTAF/TEinterface.FordetaileddefinitionofthesynchronisationproceduresrefertoGSM07.01.8.1.7IdleframesWhenevernodataisreceivedfromtheradiointerface(e.g.framestealingapplies,layer2fillframesarereceived,etc.)idleframesshallbesenttotheDTE.TheseareV.110frameswithframealignmentpatternaccordingtoCCITTrecommendation.V.110[11]andalldata,statusandE-bitssettobinary"1".8.2MultislotratesInmultislotoperationthetransmissionisperformedusingparallelsubstreamsbetweentheSplit/Combine-functions.SIST EN 300 945 V7.0.3:2003

ETSIETSIEN300945V7.0.3(1999-12)20(GSM04.21version7.0.3Release1998)8.2.1TCH/F14.4multislotoperationTheinformationcarriedbytheM2-sequencesisreadpersubstream;i.e.thesubstreamnumberandacompleteNIC-codearetransferredthroughonesubstream.ANIC-codeiscarriedonasmanysubstreamsasisnecessarytocoverallNIC-compensationsthathavetakenplace.OnchannelswherenoNIC-compensationiscarried,theN-bitsaresetto'nocompensation'.FortheexactNIC-procedures,refertosubclause10.5.1.8.2.2AIURsupto38,4kbit/susingTCH/F9.6andTCH/F4.8channelcodingsIntermediaterate/AIURRadiointerfacerate16kbit/s/9,6kbit/s2×6kbit/s32kbit/s/14,4;19,2kbit/s2×12or3×6or4×6kbit/s64kbit/s/28,8;38,4kbit/s3×12or4×12kbit/sInthesecases,thedatastreamismappedfrom80-bitintermediaterateframesintomodifiedframesof60bitsforradio-interfacetransmissionasspecifiedinsubclause8.1for12kbit/sand6kbit/sexceptforthefollowingcases:ForAIURs14,4and28,8kbit/susingchannelcodingsTCH/F4.8andTCH/F9.6,respectively,fourconsecutiveV.11080-bitframes(Figure12)aremappedontothreeconsecutivemodified60-bitV.110(Figure5or6)framesattheMS.The4×36databitsinthe80-bitframesaremappedontothe3×48databitsinthe60-bitframes.However,bitsE4-E7inthe80-bitframesaremappedontotheE4-E7bitsinthe60-bitframeswhentheirvalueindicateeitherpositiveornegativecompensation(NIC;Seesubclause5.1.1).TheE4-E7bitsthatindicate'Nocompensation'inthe80-bitframesneednotbemappedontothe60-bitframes.TheS-andX-bitsineveryfourth80-bitframearenotmappedontothe60-bitframes.Whenradiointerfacerateof2×12kbit/sisusedforcarryingAIUR14,4kbit/s,paddingisusedinthe60-bitframesofthehighersubstreamnumber(Subclause10.6).Forsubstreamnumberinginformation,pleaserefertosubclause10ofthepresentdocument.8.2.3AIURsupto38,4kbit/susingTCH/F14.4channelcodingIntermediaterate/AIURRadiointerfacerate64kbit/s/28,8;38,4kbit/s2×14,5or3×14,5ForAIURs14,4and28,8kbit/sthe36databitsinthe80-bitV.110intermediaterateframesareextractedandsentthroughthesubstreamsindatablockscontainingeight36-bitframesasdescribedinsubclause8.1.AnM1/M2-bitpairissentovertheradio-interfacealongwitheachdatablockevery20ms.Thesebitscarrythemultiframe,substreamnumber,V.24status,andNICinformationasdescribedinsubclauses8.1.1.1and8.2.1.ForAIUR38.4kbit/sthe80-bitV.110intermediaterateframescarry48userdatabits.The290-bitblocksinthesubstreamsofthelowersubstreamnumberscarry288userdatabitswhilethe290-bitblocksinthesubstreamofthehighestsubstreamnumbercarries192userdatabits;thismeansthatfiveoftheeight36-bitframesmakinguptheblockcarry36userdatabitswhereasthesixthframecarries12userdatabits(5×36+12).Framesseven,eight,andtherestofthesixthframearepaddedwith'1's.TheM2-bitsequencesareusedasdescribedinsubclauses8.1.1.1and8.2.1ForNIC-proceduresrefertosubclauses8.2.1and10.5.1.NoNIC-valuesaretransportedinassociationwithAIUR38,4;theN-bitsaresetto'nocompensation'.SIST EN 300 945 V7.0.3:2003

ETSIETSIEN300945V7.0.3(1999-12)21(GSM04.21version7.0.3Release1998)8.2.4AIURof48kbit/s;Intermediaterateof64kbit/s;Radiointerfacerateof5x12kbit/sOnemodifiedCCITTV.11060bitframe(Figure5)isreceived/sentfrom/toaTCH/Fev
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