TS 100 946 - V7.1.0 - Digital cellular telecommunications system (Phase 2+); Radio Link Protocol (RLP) for data and telematic services on the Mobile Station - Base Station System (MS - BSS) interface and the Base Station System - Mobile-services Switching

65 Pages·0.94 MB·English

by  European Telecommunications Standards Institute

ETSI TS 100 946
V7.1.0
(2000-01)
TechnicalSpecification
Digital cellular telecommunications system (Phase 2+);
Radio Link Protocol (RLP) for data and telematic services
on the Mobile Station - Base Station System (MS - BSS)
interface and the
Base Station System - Mobile-services Switching Centre
(BSS - MSC) interface
(GSM 04.22 version 7.1.0 Release 1998)
R
GLOBALSYSTEM FOR
MOBILECOMMUNICATIONS
(GSM04.22version7.1.0Release1998) 2 ETSITS100946V7.1.0(2000-01)
Reference
RTS/SMG-040422Q7R1
Keywords
Digitalcellulartelecommunicationssystem,
GlobalSystemforMobilecommunications(GSM)
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ETSI
(GSM04.22version7.1.0Release1998) 3 ETSITS100946V7.1.0(2000-01)
Contents
IntellectualPropertyRights................................................................................................................................5
Foreword............................................................................................................................................................5
1 Scope........................................................................................................................................................6
2 References................................................................................................................................................6
2.1 Definitionsandabbreviations.............................................................................................................................7
3 Introduction..............................................................................................................................................8
4 Framestructure.........................................................................................................................................9
4.1 Basicframestructure..........................................................................................................................................9
4.2 RLPheader.........................................................................................................................................................9
4.3 Orderoftransmission.........................................................................................................................................9
4.4 Framechecksequence........................................................................................................................................9
5 Elementsandprocedure.........................................................................................................................10
5.1 Modes...............................................................................................................................................................10
5.1.1 AsynchronousBalancedMode(ABM).......................................................................................................10
5.1.2 AsynchronousDisconnectedMode(ADM)................................................................................................10
5.2 Headerandparameters.....................................................................................................................................11
5.2.1 Generallyusedbits......................................................................................................................................11
5.2.1.1 Command/responsebit,C/R..................................................................................................................11
5.2.1.2 Poll/Finalbit,P/F..................................................................................................................................12
5.2.2 Unnumberedframes,U...............................................................................................................................12
5.2.2.1 SetasynchronousbalancedmodeSABM(11100)................................................................................12
5.2.2.2 UnnumberedAcknowledge.UA(00110)..............................................................................................12
5.2.2.3 Disconnect,DISC(00010)....................................................................................................................12
5.2.2.4 DisconnectedMode,DM(11000).........................................................................................................12
5.2.2.5 UnnumberedInformation,UI(00000)..................................................................................................12
5.2.2.6 ExchangeIdentification,XID(11101)..................................................................................................13
5.2.2.7 Test,TEST(00111)..............................................................................................................................14
5.2.2.8 Nullinformation,NULL(11110)..........................................................................................................14
5.2.2.9 REMAP(10001)...................................................................................................................................14
5.2.3 Supervisoryframes,S,andnumberedinformationtransferandsupervisoryframescombined,I+S..........15
5.2.3.1 Numbering.............................................................................................................................................15
5.2.3.2 SendSequencenumber,N(S)................................................................................................................15
5.2.3.3 Receivesequencenumber,N(R)...........................................................................................................15
5.2.3.4 L2RStatusbit........................................................................................................................................15
5.2.3.5 Receiveready,RR(00).........................................................................................................................15
5.2.3.6 Reject,REJ(01)....................................................................................................................................16
5.2.3.7 Receivenotready,RNR(10)................................................................................................................16
5.2.3.8 Selectivereject,SREJ(11)....................................................................................................................16
5.2.3.9 UpgradingProposalbit,UPbit.............................................................................................................16
5.3 ErrorRecovery.................................................................................................................................................17
5.3.1 Improperframes..........................................................................................................................................17
5.3.2 N(S)sequenceerror....................................................................................................................................17
5.3.3 N(R)error...................................................................................................................................................17
5.3.4 Time-outandcheckpointing.......................................................................................................................17
5.3.4.1 Treatmentoferrorsduringlinkestablishment,linkresetandlinkdisconnect......................................17
5.3.4.2 Treatmentoferrorsduringnumberedinformationtransfer...................................................................18
5.3.5 Contentioussituations.................................................................................................................................18
5.4 TransitionsbetweenTCH/F9.6andTCH/F14.4channelcodings....................................................................18
5.5 Listofsystemparameters.................................................................................................................................19
5.5.1 RLPVersionN°..........................................................................................................................................19
5.5.2 MaximumnumberofoutstandingIframesk(Windowsize)......................................................................20
5.5.3 TimerT1.....................................................................................................................................................20
5.5.4 MaximumnumberofretransmissionsN2...................................................................................................20
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5.5.5 DataCompressionParameters....................................................................................................................20
5.5.6 Re-sequencingperiod(TimerT4)...............................................................................................................21
5.5.7 Optionalfeatures.........................................................................................................................................21
5.6 Supportfordiscontinuoustransmission(DTX)................................................................................................21
6 Servicedefinitions..................................................................................................................................21
6.1 Introduction......................................................................................................................................................21
6.2 Conventions......................................................................................................................................................22
6.3 Queuemodel.....................................................................................................................................................22
6.4 ListofPrimitives..............................................................................................................................................24
6.5 PossibleRLPtimesequencediagrams.............................................................................................................25
AnnexA(informative): RLPSDLDiagrams.......................................................................................28
A.1 ListofRLPentitystates.........................................................................................................................28
A.1.1 (main)states.....................................................................................................................................................28
A.1.2 statevariables...................................................................................................................................................28
A.2 ListofRLPentityevents........................................................................................................................32
AnnexB(Informative): Changehistory...............................................................................................64
History..............................................................................................................................................................65
ETSI
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Intellectual Property Rights
IPRsessentialorpotentiallyessentialtothepresentdocumentmayhavebeendeclaredtoETSI.Theinformation
pertainingtotheseessentialIPRs,ifany,ispubliclyavailableforETSImembersandnon-members,andcanbefound
inSR000314:"IntellectualPropertyRights(IPRs);Essential,orpotentiallyEssential,IPRsnotifiedtoETSIinrespect
ofETSIstandards",whichisavailablefromtheETSISecretariat.LatestupdatesareavailableontheETSIWebserver
(http://www.etsi.org/ipr).
PursuanttotheETSIIPRPolicy,noinvestigation,includingIPRsearches,hasbeencarriedoutbyETSI.Noguarantee
canbegivenastotheexistenceofotherIPRsnotreferencedinSR000314(ortheupdatesontheETSIWebserver)
whichare,ormaybe,ormaybecome,essentialtothepresentdocument.
Foreword
ThisTechnicalSpecification(TS)hasbeenproducedbytheSpecialMobileGroup(SMG).
ThepresentdocumentspecifiestheRadioLinkProtocol(RLP)fordatatransmissionoverwithinthedigitalcellular
telecommunicationssystem.
ThecontentsofthepresentdocumentissubjecttocontinuingworkwithinSMGandmaychangefollowingformalSMG
approval.ShouldSMGmodifythecontentsofthepresentdocument,itwillbere-releasedbySMGwithanidentifying
changeofreleasedateandanincreaseinversionnumberasfollows:
Version7.x.y
where:
7 indicatesGSMPhase2+Release1998;
x theseconddigitisincrementedforallchangesofsubstrance,i.e.technicalenhancements,corrections,
updates,etc.;
y thethirddigitisincrementedwheneditorialonlychangeshavebeenincorporatedinthespecification.
ETSI
(GSM04.22version7.1.0Release1998) 6 ETSITS100946V7.1.0(2000-01)
1 Scope
ThepresentdocumentspecifiestheRadioLinkProtocol(RLP)fordatatransmissionovertheGSMPLMN.RLPcovers
theLayer2functionalityoftheISOOSIReferenceModel(IS7498).ItisbasedonideascontainedinIS3309,IS4335
andIS7809(HDLCofISO)aswellasCCITTX.25andQ.92x(LAP-BandLAP-DofCCITT,respectively.)RLPhas
beentailoredtothespecialneedsofdigitalradiotransmission.RLPprovidestoitsuserstheOSIDataLinkService(IS
8886).
RLPisintendedforusewithnon-transparentdata-transfer.Protocolconversionmaybeprovidedforavarietyof
protocolconfigurations.Thoseforeseenimmediatelyare:
- Character-modeprotocolsusingstart-stoptransmission(IA5);
- X.25LAP-B.
Forreasonsofbetterpresentation,materialaboutprotocolconversionhasbeenplacedwithinthoseSpecifications
concernedwiththerelevantTerminalAdaptors,i.e.GSM07.02fortheasynchronouscaseandGSM07.03forthe
synchronouscase.CaremustbetakenthatthatmaterialalsoappliestoInterworkingFunctions;seeGSM09.04-09.07.
2 References
Thefollowingdocumentscontainprovisionswhich,throughreferenceinthistext,constituteprovisionsofthepresent
document.
• Referencesareeitherspecific(identifiedbydateofpublication,editionnumber,versionnumber,etc.)or
non-specific.
• Foraspecificreference,subsequentrevisionsdonotapply.
• Foranon-specificreference,thelatestversionapplies.
• Anon-specificreferencetoanETSshallalsobetakentorefertolaterversionspublishedasanENwiththesame
number.
• ForthisRelease1998document,referencestoGSMdocumentsareforRelease1998versions(version7.x.y).
[1] GSM01.04:"Digitalcellulartelecommunicationsystem(Phase2+);Abbreviationsandacronyms".
[2] GSM04.21:"Digitalcellulartelecommunicationsystem(Phase2+);RateadaptionontheMobile
Station-BaseStationSystem(MS-BSS)interface".
[3] GSM07.02:"Digitalcellulartelecommunicationsystem(Phase2+);TerminalAdaptation
Functions(TAF)forservicesusingasynchronousbearercapabilities".
[4] GSM07.03:"Digitalcellulartelecommunicationsystem(Phase2);TerminalAdaptationFunctions
(TAF)forservicesusingsynchronousbearercapabilities".
[5] GSM09.04:"Digitalcellulartelecommunicationsystem(Phase2+);Interworkingbetweenthe
PublicLandMobileNetwork(PLMN)andtheCircuitSwitchedPublicDataNetwork(CSPDN)".
[6] GSM09.05:"Digitalcellulartelecommunicationsystem(Phase2+);Interworkingbetweenthe
PublicLandMobileNetwork(PLMN)andthePacketSwitchedPublicDataNetwork(PSPDN)for
PacketAssembly/Disassemblyfacility(PAD)access".
[7] GSM09.06:"Digitalcellulartelecommunicationsystem(Phase2+);Interworkingbetweena
PublicLandMobileNetwork(PLMN)andaPacketSwitchedPublicDataNetwork/Integrated
ServicesDigitalNetwork(PSPDN/ISDN)forthesupportofpacketswitcheddatatransmission
services".
ETSI
(GSM04.22version7.1.0Release1998) 7 ETSITS100946V7.1.0(2000-01)
[8] GSM09.07:"Digitalcellulartelecommunicationssystem(Phase2+);Generalrequirementson
interworkingbetweenthePublicLandMobileNetwork(PLMN)andtheIntegratedServices
DigitalNetwork(ISDN)orPublicSwitchedTelephoneNetwork(PSTN)".
[9] CCITTRecommendationI.440(Redbook):"ISDNuser-networkinterfacedatalinklayer-General
aspects".
[10] CCITTRecommendationI.441(Redbook):"ISDNuser-networkinterface,datalink".
[11] CCITTRecommendationQ.920(Redbook):"ISDNuser-networkinterfacedatalinklayer-
Generalaspects".
[12] CCITTRecommendationQ.921(Redbook):"ISDNuser-networkinterface-datalink".
[13] CCITTRecommendationQ.921bis:"AbstracttestsuitesforLAPDconformancetests".
[14] CCITTRecommendationQ.922:"ISDNdatalinklayerspecificationforframemodebearer
services".
[15] CCITTRecommendationV.42bis:"DataCompressionforDataCircuitTerminatingEquipment
(DCE)usingErrorCorrectionProcedures".
[16] CCITTRecommendationX.25(Redbook):"InterfacebetweenDataTerminalEquipment(DTE)
andDataCircuitTerminatingEquipment(DCE)forterminalsoperatinginPacketModeand
connectedtoPublicDataNetworksbydedicatedCircuit".
[17] ISO/IECRecommendation4335:"Informationtechnology-Telecommunicationsandinformation
exchangebetweensystems-Highleveldatalinkcontrol(HDLC)procedures-Elementsof
procedures".
[18] ISORecommendation3309:"Informationtechnology-Telecommunicationsandinformation
exchangebetweensystems-Highleveldatalinkcontrol(HDLC)procedures-Framestructure".
[19] ISORecommendation7498:"Informationprocessingsystems-OpenSystemsInterconnection-
BasicReferenceModel".
[20] ISORecommendation8885:"Informationtechnology-Telecommunicationandinformation
exchangebetweensystems-High-leveldatalinkcontrol(HDLC)procedures-Generalpurpose
XIDframeinformationfieldcontentandformat".
[21] ISORecommendation8886:"Informationtechnology-Telecommunicationandinformation
exchangebetweensystems-DatalinkservicedefinitionsforOpenSystemsinterconnection".
[22] ISORecommendation8509:"Informationprocessingsystems-OpenSystemsInterconnection-
Serviceconventions".
[23] ISO/IECRecommendation7809:"Informationtechnology-Telecommunicationandinformation
exchangebetweensystems-High-leveldatalinkcontrol(HDLC)procedures-Classesof
procedures".
[24] ISORecommendation7776:"Informationprocessingsystems-High-leveldatalinkcontrol
procedures-DescriptionoftheX.25LAPB-compatibleDTEdatalinkprocedures".
2.1 Definitions and abbreviations
AbbreviationsusedinthepresentdocumentarelistedinGSM01.04[1].
Forthepurposesofthepresentdocument,thefollowingtermsanddefinitionsapply.
backwardscompatibility:RLPdefinesseveralbackwards-compatibleversions.Thatmeansthatanewerversioncan
interworkwithanolderonewithoutchangingtheolderone.ThisisrealizedbyafallbackmechanismduringXID
exchange.
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command:AninstructionrepresentedintheRLPheader,causingthereceivingRLPentitytoexecuteaspecific
function.
framechecksequence:Afieldofredundantinformationbasedonacycliccode,usedforerrordetection.
I+Sframe:AnRLPframethatisusedforuserinformationtransfer,carryingsupervisoryinformationpiggyback.
improperframe:AnRLPframehavinganFCSerrororhavingaheaderthecontentsofwhichisinconsistentwiththis
Specification.
non-transparent:InPLMNdatatransmission,aconfigurationwhereatlayer2,protocolinformationofthefixed
networkismappedonRLPelements,andviceversa.
piggybacking:MeansbywhichoneandthesameframecancarrybothuserinformationandRLPrelatedsupervisory
information.
response:AreplyrepresentedintheRLP-header,bywhichthesendingRLPentityreportsbackaboutitsstatus.
RLPframe:Asequenceofcontiguousbits,representinganRLPproceduralelement.
RLPheader:ThatpartofanRLPframethatencodeseitheracommandoraresponse,locatedatthebeginningofthe
RLPframe.
Sframe:AnRLPframethatcontainssupervisoryinformationintheabsenceofuserinformation.
transparent:InPLMNdatatransmission,aconfigurationwhereatlayer2(andalsoatthelayersabove)noprotocol
conversiontakesplace.
Uframe:AnRLPframethatcontainsunnumberedprotocolcontrolinformation.
3 Introduction
ThreeversionsofRLParedefined:
- RLPversion0:single-linkbasicversion;
- RLPversion1:single-linkextendedversion(e.g.extendedbydatacompression);
- RLPversion2:multi-linkversion.
RLPusesone(single-link)orfrom1upto4(multi-link)physicallinks.However,theRLPmulti-linkversionis
designedtobeabletosupportupto8physicallinks.If,inthecallsetupsignalling,eitherendindicatesthatitcannot
supportmultilinkoperation,neitherendshallrequireusageofRLP-versionshigherthan1.IftheBCnegotiationduring
callsetupresultsinapossibilityformulti-linkoperationduringthecall,bothendsshallrequireandacceptRLPversion
2only.
IftheBCnegotiationduringcallsetupresultsinmaximumnumberoftrafficchannels=1TCHandUIMI=not
required/notallowedorupto1TCH/Fallowed/mayberequested,thisisinterpretedasifatleastoneenddoesnot
supportmultilinkoperation,andneitherendshallrequireRLPversionhigherthan1.
RLPmakesuseofanunderlyingFEC(ForwardErrorCorrection)mechanism.ForRLPtoperformadequatelyitis
assumedthatthebasicradiochanneltogetherwithFECprovidesforablockerrorrateoflessthan10%,whereablock
consistsof240or576bits(FurtherstudyontheBLERfor576-bitblocksisneeded).Furthermore,itisassumedthatin
caseofmulti-linkRLPthedifferenceofthedelaybetweenallphysicallinksislessthantimerT4.
RLPframesaresentinstrictalignmentwiththeradiotransmission.(Fordetails,seeGSM04.21).RLPframesareofa
fixedsizeof240(TCH/F9.6channelcoding)or576bits(TCH/F14.4channelcoding).Wheneveraframeistobesent,
theRLPentityhastoprovidethenecessaryprotocolinformationtobecontainedinit.Provisionismadefor
discontinuoustransmission(DTX).
RLPspansfromtheMobileStation(MS)totheinterworkingfunction(IWF),locatedatthenearestMobileSwitching
Centre(MSC),orbeyond.DependingontheexactlocationoftheIWF,handoveroftheMSmayresultinlink-resetor
eventotallossoftheconnection.
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TheMSshallinitiatetheRLPlink.InadditiontheMSC/IWFmayinitiatetheRLPlink.
IntheterminologyofHDLC,RLPisusedinabalancedconfiguration,employingasynchronousoperation,i.e.either
stationhastherighttoset-up,reset,ordisconnectalinkatanytime.Proceduralmeansareprovidedfortodealwith
contentioussituations,shouldtheyeveroccur.
RLPisfull-duplexinthesensethatitallowsforinformationtobetransferredinbothdirectionssimultaneously.
4 Frame structure
4.1 Basic frame structure
AnRLP-framehasafixedlengthofeither240or576bitsconsistingofaheader,aninformationfield,andanFCS
(framechecksequence)field.Thesizeofthecomponentsdependsonthetheradiochanneltype,RLPversionandon
theRLPframe.Asabenefitofusingstrictalignmentwithunderlyingradiotransmissionthereisnoneedforframe
delimiters(likeflagsetc.)inRLP.Inconsequence,thereisno"bit-stuffing"necessaryinordertoachievecode
transparency.Framescannotbeabortedwhilebeingtransmitted.
a)240bitframesize
Header Information FCS
version0and1,version2(Uframesonly) 16bit 200bit 24bit
version2(SandI+Sframesonly) 24bit 192bit 24bit
b)576bitframesize
Header Information FCS
version0,1,andversion2(Uframesonly) 16bit 536bit 24bit
version2(SandI+Sframesonly) 24bit 528bit 24bit
Figure1:Framestructure
4.2 RLP header
AnRLP-headercarriesoneofthreetypesofcontrolinformation,thefirstbeingunnumberedprotocolcontrol
information(Uframes),thesecondbeingsupervisoryinformation(Sframes),thethirdbeinguserinformationcarrying
supervisoryinformationpiggybacked(I+Sframes).
4.3 Order of transmission
Theheader,asdefinedinclause5.2,shallbetransmittedfromlefttoright.TheFCSshallbetransmittedcommencing
withthehighestorderterm.Theorderofbittransmissionfortheinformationfieldisfromlefttoright.
4.4 Frame check sequence
TheFCSshallbetheonescomplementofthemodulo2sumof:
a) theremainderof:
For9.6/4.8kbit/schannelcoding:
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x216(x23+x22+x21+x20+x19+x18+x17+x16+x15+x14+x13+x12+x11+x10+x9+x8+x7+x6+x5+x4+
x3+x2+x+1)
For14.4kbit/schannelcoding:
x552(x23+x22+x21+x20+x19+x18+x17+x16+x15+x14+x13+x12+x11+x10+x9+x8+x7+x6+x5
+x4+x3+x2+x+1
dividedmodulo2bythegeneratorpolynomial:
x24+x23+x21+x20+x19+x17+x16+x15+x13+x8+x7+x5+x4+x2+1
and
b) theremainderofthedivisionmodulo2bythegeneratorpolynomial:
x24+x23+x21+x20+x19+x17+x16+x15+x13+x8+x7+x5+x4+x2+1
oftheproductofx24bythecontentoftheframe,excludingtheFCSfield.(Thefirstbittransmittedcorresponds
tothehighestorderterm.)
Implementationnote:Asatypicalimplementation,atthetransmitter,theinitialcontentoftheregisterofthedevice
computingtheremainderofthedivisionispre-settoallonesandisthenmodifiedbydivisionbythegenerator
polynomial(asdescribedabove)oftheheaderandinformationfield;theonescomplementoftheresultingremainderis
transmittedasthe24bitFCSsequence.
Atthereceiver,theinitialcontentoftheregisterofthedevicecomputingtheremainderispre-settoallones.Thefinal
remainderaftermultiplicationbyx24andthendivision(modulo2)bythegeneratorpolynomial:
x24+x23+x21+x20+x19+x17+x16+x15+x13+x8+x7+x5+x4+x2+1
oftheserialincomingprotectedbitsandtheFCSwillbe:
011011011000100100110000(x23tox0,resp.)
intheabsenceoftransmissionerrors.
5 Elements and procedure
5.1 Modes
AnRLPentitycanbeinoneoftwomodes:
- AsynchronousBalancedMode(ABM)
- AsynchronousDisconnectedMode(ADM)
5.1.1 Asynchronous Balanced Mode (ABM)
InABM,whichisthedatalinkoperationalmode,eitherRLPentitymaysendcommandsatanytimeandmayinitiate
responseframetransmissionwithoutreceivingexplicitpermissiontodosofromtheotherRLP-station.InABM,frames
shallbeusedforinformationfieldtransferand/ortoindicatestatuschangesintheRLP-station.
5.1.2 Asynchronous Disconnected Mode (ADM)
InADM,whichisthedata-linknon-operationalmode,theRLPentityshallbelogicallydisconnectedfromthedatalink
andshall,therefore,neithertransmitnoracceptnumberedinformationframes.
ETSI