SIST EN 300 948 V7.1.1:2003

• Abstract:

  Upgrade from Phase 2+ to Release 1998

• 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 300 948 V7.1.1 (2000-05) - Digital cellular telecommunications system (Phase 2+) (GSM); Group Call Control (GCC) protocol (GSM 04.68 version 7.1.1 Release 1998)

Overview

SIST EN 300 948 V7.1.1:2003 is a Slovenian standard that is fully aligned with the European Standard EN 300 948, version 7.1.1. This document specifies the Group Call Control (GCC) protocol for the Voice Group Call Service (VGCS) within digital cellular telecommunications systems (GSM, Phase 2+), specifically aligning with GSM 04.68 version 7.1.1, Release 1998. Part of the global initiative to standardize GSM technologies, this standard describes the procedures, state management, and messaging required for group call handling over the radio interface between mobile stations (MS) and the network.

The main scope of this standard is to support the transition from GSM Phase 2+ to Release 1998, ensuring compatibility and refinement of group call services for public and private mobile communication networks.

Key Topics

• Group Call Control (GCC) Protocol: Detailed specification of the protocol entities and message flows for group call handling between mobile stations and the GSM network.
• Voice Group Call Service (VGCS): Defines how voice calls can be simultaneously established and managed across groups of mobile stations.
• GCC States and Procedures: Formalizes the states (idle, pending, initiated, active, etc.) and transitions for both mobile stations and network-side entities during group call operations.
• Elementary Procedures: Covers the key functional building blocks such as call establishment, termination, call information, and error handling.
• Compatibility: Ensures backward and forward compatibility with previous GSM releases, supporting both mobile- and network-initiated group calls.
• Error Handling and Consistency: Defines how the protocol manages abnormal events, inconsistencies, and signaling errors to maintain reliable service.

Applications

SIST EN 300 948 V7.1.1:2003 is essential for telecommunications vendors, operators, and integrators focused on the deployment and maintenance of GSM group call services. Typical areas of practical application include:

• Public Safety and Emergency Services: Enables reliable group communication for police, fire, and rescue operations, where instant, coordinated voice calls are critical.
• Railway and Transportation Communications: Supports operational group communications, including train crew and dispatch communication needs.
• Enterprise Private Mobile Networks: Facilitates efficient communication among defined user groups within large industrial or corporate sites.
• Multinational Radio Coverage: Ensures standardized group calling functionality across international GSM networks, supporting roaming and interoperability.

Implementing the GCC protocol according to this standard guarantees that group call features operate seamlessly and securely, maximizing the reliability and scalability of GSM-based services.

Related Standards

Compliance and interoperability are enhanced by referencing key related GSM standards, including:

• GSM 02.68: Voice Group Call Service (VGCS) - service description and requirements.
• GSM 03.68: VGCS architecture and functional aspects.
• GSM 04.08: Mobile radio interface layer 3 specification.
• GSM 04.07: Layer 3 general aspects, including Connection Management (CM) sublayer.
• GSM 01.04: Abbreviations and acronyms for GSM.

This standard also aligns with other ETSI and SIST documents governing GSM radio interfaces, numbering, addressing, and signaling procedures.

---

By adhering to SIST EN 300 948 V7.1.1:2003, implementers ensure robust support for group call communication, excellent service reliability, and full compatibility within the GSM ecosystem, supporting evolving user needs and regulatory requirements in digital mobile telecommunications.

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.NUPLOMHQMDDigital cellular telecommunications system (Phase 2+) (GSM); Group Call Control (GCC) protocol (GSM 04.68 version 7.1.1 Release 1998)33.070.50Globalni sistem za mobilno telekomunikacijo (GSM)Global System for Mobile Communication (GSM)ICS:Ta slovenski standard je istoveten z:EN 300 948 Version 7.1.1SIST EN 300 948 V7.1.1:2003en01-december-2003SIST EN 300 948 V7.1.1:2003SLOVENSKI
STANDARD
ETSIEN300948V7.1.1(2000-04)EuropeanStandard(Telecommunicationsseries)Digitalcellulartelecommunicationssystem(Phase2+);GroupCallControl(GCC)protocol(GSM04.68version7.1.1Release1998)GLOBALSYSTEMFORMOBILECOMMUNICATIONSRSIST EN 300 948 V7.1.1:2003

ETSIETSIEN300948V7.1.1(2000-04)2(GSM04.68version7.1.1Release1998)ReferenceREN/SMG-030468Q7R1KeywordsDigitalcellulartelecommunicationssystem,GlobalSystemforMobilecommunications(GSM)ETSI650RoutedesLuciolesF-06921SophiaAntipolisCedex-FRANCETel.:[phone]Fax:[phone]SiretN°34862356200017-NAF742CAssociationàbutnonlucratifenregistréeàlaSous-PréfecturedeGrasse(06)N°7803/88ImportantnoticeIndividualcopiesofthepresentdocumentcanbedownloadedfrom:http://www.etsi.orgThepresentdocumentmaybemadeavailableinmorethanoneelectronicversionorinprint.Inanycaseofexistingorperceiveddifferenceincontentsbetweensuchversions,thereferenceversionisthePortableDocumentFormat(PDF).Incaseofdispute,thereferenceshallbetheprintingonETSIprintersofthePDFversionkeptonaspecificnetworkdrivewithinETSISecretariat.Usersofthepresentdocumentshouldbeawarethatthedocumentmaybesubjecttorevisionorchangeofstatus.InformationonthecurrentstatusofthisandotherETSIdocumentsisavailableathttp://www.etsi.org/tb/status/Ifyoufinderrorsinthepresentdocument,sendyourcommentto:[e-mail]opartmaybereproducedexceptasauthorizedbywrittenpermission.Thecopyrightandtheforegoingrestrictionextendtoreproductioninallmedia.©EuropeanTelecommunicationsStandardsInstitute2000.Allrightsreserved.SIST EN 300 948 V7.1.1:2003

ETSI3ETSIEN300948V7.1.1(2000-04)(GSM04.68version7.1.1Release1998)ContentsIntellectualPropertyRights.5Foreword.51Scope.62References.63Definitionsandabbreviations.63.1Definitions.63.2Abbreviations.74Applicability.75Mainconcepts.76ElementaryproceduresforGroupCallControl.86.1Overview.86.1.1General.86.1.2Groupcallcontrolstates.106.1.2.1GroupcallcontrolstatesattheMSsideoftheinterface.106.1.2.1.1AttributesandparametersofGCCintheMS.106.1.2.1.2NULL(U0).106.1.2.1.3MMCONNECTIONPENDING(U0.p).106.1.2.1.4GROUPCALLINITIATED(U1).106.1.2.1.5GROUPCALLACTIVE(U2).116.1.2.1.6GROUPCALLPRESENT(U3).116.1.2.1.7GROUPCALLCONNECTIONREQUESTED(U4).116.1.2.1.8TERMINATIONREQUESTED(U5).116.1.2.1.9Sub-statesoftheGroupcallactivestate.116.1.2.1.10GCCTimersintheMS.126.1.2.1.11Consistencyofparametersandstates.126.1.2.2Groupcallcontrolstatesatthenetworksideoftheinterface.136.1.2.2.1NULL(StateN0).136.1.2.2.2GROUPCALLINITIATED(N1).136.1.2.2.3GROUPCALLACTIVE(N2).136.1.2.2.4GROUPCALLESTABLISHMENTPROCEEDING(N3).136.1.2.2.5TERMINATIONREQUESTED(N4).136.2Proceduresforestablishmentofagroupcall.136.2.1Activationofagroupcallbythenetwork.136.2.2Mobileoriginatedestablishment.136.2.2.1Terminationduringmobileoriginatedestablishment.146.2.2.2Abnormalcases.146.2.3MobileterminatinggroupcallestablishmentintheMS.156.3Proceduresduringtheactivestateofagroupcall.156.3.1Mobilestationproceduresintheactivestate.156.3.1.1Sub-statetransitionsintheMS.156.3.2Networkproceduresintheactivestate.166.4Proceduresforrelease,abortion,andterminationofagroupcall.166.4.1Terminationprocedure.166.4.2Abortandreleaseprocedures.166.5Miscellaneousprocedures.176.5.1Statusprocedures.176.5.1.1Getstatusprocedure.176.5.1.2Setparameterprocedure.177Handlingofunknown,unforeseen,anderroneousprotocoldata.177.1General.177.2Messagetooshort.187.3Unknownorunforeseentransactionidentifier.18SIST EN 300 948 V7.1.1:2003

ETSIETSIEN300948V7.1.1(2000-04)4(GSM04.68version7.1.1Release1998)7.4Unknownorunforeseenmessagetype.187.5Non-semanticalmandatoryinformationelementerrors.187.6Unknownandunforeseeninformationelementsinthenon-imperativemessagepart.197.6.1Informationelementsunknowninthemessage.197.6.2Outofsequenceinformationelements.197.6.3RepeatedInformationelements.197.7Non-imperativemessageparterrors.197.7.1SyntacticallyincorrectoptionalInformationelements.197.8Messageswithsemanticallyincorrectcontents.198Messagefunctionaldefinitionsandcontents.208.1CONNECT.208.2GETSTATUS.218.2.1mobileidentity.218.3IMMEDIATESETUP.218.3.1Mobileidentity.228.4SETPARAMETER.228.5SETUP.228.6STATUS.238.6.1Callstate.238.6.2Stateattributes.238.7TERMINATION.248.8TERMINATIONREJECT.248.9TERMINATIONREQUEST.249Contentsofinformationelementsvalueparts.259.1ProtocolDiscriminator.259.2Transactionidentifier.259.3MessageType.259.4Otherinformationelements.269.4.1CallReference.269.4.2Callstate.269.4.3Cause.279.4.4Originatorindication.289.4.5Notused.299.4.6SpareHalfOctet.299.4.7Stateattributes.29AnnexA(informative):ChangeRequestHistory.30History.31SIST EN 300 948 V7.1.1:2003

ETSI5ETSIEN300948V7.1.1(2000-04)(GSM04.68version7.1.1Release1998)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)hasbeenproducedbyETSITechnicalCommitteeSpecialMobileGroup(SMG),andisnowsubmittedfortheETSIstandardsOne-stepApprovalProcedure.ThepresentdocumentspecifiestheGroupCallControl(GCC)protocolusedbytheVoiceGroupCallService(VGCS)ontheradiointerfacewithinthedigitalcellulartelecommunicationssystem(Phase2+).ThecontentsofthepresentdocumentissubjecttocontinuingworkwithinTC-SMGandmaychangefollowingformalTC-SMGapproval.ShouldTC-SMGmodifythecontentsofthepresentdocument,itwillberesubmittedforOAPbyETSIwithanidentifyingchangeofreleasedateandanincreaseinversionnumberasfollows:Version7.x.y7IndicatesGSMPhase2+Release1998;xtheseconddigitisincrementedforallchangesofsubstance,i.e.technicalenhancements,corrections,updates,etc.;ythethirddigitisincrementedwheneditorialonlychangeshavebeenincorporatedinthespecification.NationaltranspositiondatesDateofadoptionofthisEN:31March2000DateoflatestannouncementofthisEN(doa):30June2000DateoflatestpublicationofnewNationalStandardorendorsementofthisEN(dop/e):31December2000DateofwithdrawalofanyconflictingNationalStandard(dow):31December2000SIST EN 300 948 V7.1.1:2003

ETSIETSIEN300948V7.1.1(2000-04)6(GSM04.68version7.1.1Release1998)1ScopeThepresentdocumentspecifiestheGroupCallControl(GCC)protocolusedbytheVoiceGroupCallService(VGCS)ontheradiointerface.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(ETR350):"Digitalcellulartelecommunicationsystem(Phase2+);Abbreviationsandacronyms".[2]GSM02.68(ETS300925):"Digitalcellulartelecommunicationsystem(Phase2+);"VoiceGroupCallService(VGCS)-Stage1".[3]GSM03.03(ETS300927):"Digitalcellulartelecommunicationsystem(Phase2+);Numbering,addressingandidentification".[4]GSM03.67(ETS300932):"Digitalcellulartelecommunicationsystem(Phase2+);"enhancedMulti-LevelPrecedenceandPre-emptionservice(eMLPP)-Stage2".[5]GSM03.68(ETS300933):"Digitalcellulartelecommunicationsystem(Phase2+);VoiceGroupCallService(VGCS)-Stage2".[6]GSM04.06(ETS300938):"Digitalcellulartelecommunicationsystem;MobileStation-BaseStationSystem(MS-BSS)interfaceDataLink(DL)layerspecification".[7]GSM04.07(ETS300939):"Digitalcellulartelecommunicationsystem(Phase2+);Mobileradiointerfacesignallinglayer3Generalaspects".[8]GSM04.08(ETS300940):"Digitalcellulartelecommunicationsystem(Phase2+);Mobileradiointerfacelayer3specification".3Definitionsandabbreviations3.1DefinitionsDefinitionsusedinthepresentdocumentarealsodefinedinGSM02.68.Forthepurposesofthepresentdocument,thefollowingtermsanddefinitionsapply.attachmentoftheuserconnection:SeeGSM04.08,subclause5.2.callinguser:GCCentityintheMobileStation(MS)initiatingorhavinginitiatedagroupcall.SIST EN 300 948 V7.1.1:2003

ETSI7ETSIEN300948V7.1.1(2000-04)(GSM04.68version7.1.1Release1998)clearingthecontextrelatedtothegroupcallestablishment:AllrunningGCCtimersintherelevantGCCentityarestopped,allattributesintherelevantGCCentityaredeleted.downlink:Networktomobilestationdirection.groupcall:Isusedinthesamesenseas"voicegroupcall".groupcallchannel:Combineduplink/downlinktobeallocatedineachcellofthegroupcallareaforaparticulargroupcall.Theuplinkcanbeusedbythepresentlytalkingservicesubscriberonly.AllMSsofthelisteningservicesubscribersinonecellshalllistentothecommondownlink.groupreceivemode:SeeGSM04.08.originatingmobilestation:Mobilestationinitiatingorhavinginitiatedthegroupcall.(Notethat,incertainsituations,aMSassumestobetheoriginatingMSofagroupcallwithoutactuallybeingtheoriginatingMSofthatgroupcall.NotethattheremaybeoneornoneoriginatingMSforagivengroupcall).uplink:Mobilestationtonetworkdirection.3.2AbbreviationsAbbreviationsusedinthepresentdocumentarealsolistedinGSM01.04.Forthepurposesofthepresentdocument,thefollowingabbreviationsapply:GCCGroupCallControl4ApplicabilitySupportofthegroupcallprotocolisoptionalintheMSandinthenetwork.5MainconceptsThepresentdocumentdescribesthegroupcallcontrol(GCC)protocol,whichisoneoftheprotocolsoftheConnectionManagement(CM)sublayer(seeGSM04.07).ThereisingeneralmorethanoneMSengagedinagroupcall.Consequently,thereisingeneralmorethanoneMSwithaGCCentityengagedinthesamegroupcall,andthereisoneGCCentityinthenetworkengagedinthatgroupcall.UnderwhichconditionsaGCCmessageispassedfromlower(sub-)layerstotheGCCentityisdefinedinthespecificationsofthesub-layers.TheMSshallignoreGCCmessagesthatitreceiveswhichweresentinunacknowledgedmodeandwhichexplicitlyspecifyasdestinationamobileidentitywhichisnotamobileidentityoftheMS.HigherlayersandtheMMsub-layerdecidewhentoacceptparallelGCCtransactionsandwhen/whethertoacceptGCCtransactionsinparalleltootherCMtransactions.Thegroupcallmaybeinitiatedbyamobileuserorbyadispatcher.Specificationofaprotocolfordispatchersisoutofthescopeofthepresentdocument.Hence,inthescopeofthepresentdocument,thereare:-oneGCCentityinthenetwork;and-oneormorethanoneGCCentitiesindifferentMSsengagedinagroupcall,andoneorenoneoftheMSsistheoriginatorofthegroupcall(calledtheoriginatingMSinthepresentdocument).Notethat,incertainsituations,aMSassumestobetheoriginatorofagroupcallwithoutbeingtheoriginator.SIST EN 300 948 V7.1.1:2003

ETSIETSIEN300948V7.1.1(2000-04)8(GSM04.68version7.1.1Release1998)TheoriginatoroftheGCCtransactionchoosestheTransactionIdentifier(TI).AMSnotassumingtobetheoriginatorofthetransactionwillchosethetransactionidentifierreceivedfromthenetwork,settingtheTIflagto1+xmod2wherexisthereceivedTIflag.Thepresentdocumentdescribesthegroupcallcontrolprotocolonlywithregardtotwopeerentities,oneinaMS,theotheroneinthenetwork.Thecallcontrolentitiesaredescribedascommunicatingfinitestatemachineswhichexchangemessagesacrosstheradiointerfaceandcommunicateinternallywithotherprotocol(sub)layers.Inparticular,theGCCprotocolusestheMMandRRsublayerspecifiedinGSM04.08.Thisdescriptioninonlynormativeasfarastheconsequentialexternallyobservablebehaviourisconcerned.Forsimplicity,insteadofusingtheterms"GCCentityintheMS"and"GCCentityinthenetwork",thepresentdocumentoftenusestheterms"MS"and"network"ifnoconfusionmayarise.Certainsequencesofactionsofthetwopeerentitiescompose"elementaryprocedures"whichareusedasabasisforthedescriptioninthepresentdocument.Theseelementaryproceduresaredefinedinclause6.ThenetworkshouldapplysupervisoryfunctionstoverifythattheGCCproceduresareprogressingandifnot,takeappropriatemeanstoresolvetheproblems.This,however,isoutofthescopeofthepresentdocument.6ElementaryproceduresforGroupCallControl6.1Overview6.1.1GeneralTheelementaryproceduresmaybegroupedintothefollowingclasses:-groupcallestablishmentprocedures;-groupcallterminationprocedures;-callinformationphaseprocedures;-miscellaneousprocedures.Figure6.1givesanoverviewofthemainstatesandtransitionsontheMSside.SIST EN 300 948 V7.1.1:2003

ETSI9ETSIEN300948V7.1.1(2000-04)(GSM04.68version7.1.1Release1998)MMConnectionpending0.PGCpresent3Null0GCconnectionrequested4Null0GCinitiated1GCactiveTerminationrequested5States1,2,3,4?L:EST-CNF!H:SETUP-IND(g-id,prio)?L:SETUP-IND(g-id,prio)?H:ABORTREQ!L:JOINGCREQ(g-id)?H:JOINGCREQ?H:SETUP-REQ(g-id,prio)!L:EST-REQ(SETUP)?H:TERM.REQ!L:ABORT-REQ!H:TERM.CNF?H:ABORTREQ!L:ABORTREQ?H:IMMSETUPREQ(g-id,prio)!L:EST-REQ(IMMSETUP)or?TimeoutH!TERMCNF?L:DI(TERMINATION)or?L:DI(TERM.REQ)?H:TERM.REQ!L:DR(TERM.REQ)?H:TERM.REQ*!L:DR(TERM.REQ)?Tnochanceexp!L:ABORTREQ?H:ABORTREQ!L:ABORTREQ!H:JOINGCCNF(mode)?L:JOINGCCNF(mode)?L:DI(CONNECT)!H:SETUP-CNF(mode)[MM-est'd](Explicit)!H:TERM-IND?L:DI(TERMINATION)!L:ABORT-REQ**?L:MM-EST_REJ!H:TERM_CONFFigure6.1:Overviewgroupcallcontrolprotocol/MSside*ifMSassumestobetheoriginatorofthegroupcall**ifnotinRRconnectedmodeSIST EN 300 948 V7.1.1:2003

ETSIETSIEN300948V7.1.1(2000-04)10(GSM04.68version7.1.1Release1998)6.1.2Groupcallcontrolstates6.1.2.1GroupcallcontrolstatesattheMSsideoftheinterfaceTheGCCentityoftheMSisdescribedasanextendedfinitestatemachine.Itperformstransitionsbetween(main)states,andinmainstateGROUPCALLACTIVE(U3)itperformstransitionsbetweensub-states.Ithascertainparametersandattributes,e.g.configurationparametersandbehaviourparameters,whichitsetsandchangesbasedoninteractionwithhigherandlower(sub-)layersandonmessageexchangewithitspeerentity.Ifaconfigurationparameterissettoacertainvalue,theMSshallalsoadapttheconfigurationaccordingly.Behaviourparametersdecideon(partof)thebehaviouroftheGCCentity.WhentheGCCentityintheMSreceivesamessage,itshallfirstanalysewhetheritshallignorethemessage,seeclauses5and7.6.1.2.1.1AttributesandparametersofGCCintheMSForthefollowingbehaviourparameters,thedescriptionisinformative.ParameterDescriptionORIGDependingonthecontext,theMSassumestobetheoriginatorofthecall(ORIG=T)ornottobetheoriginatorofthecall(ORIG=F).COMMDependingonthecontext,theMSassumesthatcommunicationwithitspeerentityisenabledinbothdirections(COMM=T)ornot(COMM=F).ForthefollowingconfigurationparameterstheMSshalladaptitsconfigurationaccordingtotheparametervalueandparameterdefinition.ParameterDefinitionD-ATTD-ATT=TmeansthattheMSattachestheuserconnectionforthegroupcallinthedownlink.D-ATT=FmeansthattheMSdoesnotattachtheuserconnectionforthegroupcallinthedownlink.U-ATTU-ATT=TmeansthattheMSattachestheuserconnectionforthegroupcallintheuplink.U-ATT=FmeansthattheMSdoesnotattachtheuserconnectionforthegroupcallintheuplink.6.1.2.1.2NULL(U0)NogroupcallexistsfortheGCCentity.Whenenteringthestate,parametersshallbesettothefollowingvalues,andconfigurationshallbeadaptedtothenewvaluesofconfigurationparameters:ORIG=F,COMM=F,D-ATT=F,U-ATT=F.6.1.2.1.3MMCONNECTIONPENDING(U0.p)TheGCCentityhasrequestedtheexplicitestablishmentofanMMconnection.Whenenteringthestate,parametersshallbesettothefollowingvalues,andconfigurationshallbeadaptedtothenewvaluesofconfigurationparameters:ORIG=T,COMM=F,D-ATT=F,U-ATT=F.6.1.2.1.4GROUPCALLINITIATED(U1)TheGCCentityhasrequestedthepeerentityinthenetworktoestablishagroupcall.Whenenteringthestate,parametersshallbesettothefollowingvalues,andconfigurationshallbeadaptedtothenewvaluesofconfigurationparameters:ORIG=T,COMM=T,D-ATT=F,U-ATT=F.SIST EN 300 948 V7.1.1:2003

ETSI11ETSIEN300948V7.1.1(2000-04)(GSM04.68version7.1.1Release1998)6.1.2.1.5GROUPCALLACTIVE(U2)Thegroupcallisestablishedatleastinonecell;dependingonthesub-state,theMShasattachedtheuserconnectionintheuplinkand/ordownlink.Thefollowingsub-statesexist:-separatelink(U2sl);-waitforreceivemode(U2wr);-receivemode(U2r);-waitforsendandreceivemode(U2ws);-sendandreceivemode(U2sr);-nochannel(U2nc).6.1.2.1.6GROUPCALLPRESENT(U3)TheMShasreceivedanotificationaboutanongoinggroupcall.Higherlayersarerequestedtoacceptorrejectthecall.Whenenteringthestate,parametersshallbesettothefollowingvalues,andconfigurationshallbeadaptedtothenewvaluesofconfigurationparameters:ORIG=F,COMM=F,D-ATT=F,U-ATT=F.6.1.2.1.7GROUPCALLCONNECTIONREQUESTED(U4)TheMShasreceivedanotificationaboutanongoinggroupcall.Higherlayershavedecidedtoacceptthecall.Whenenteringthestate,parametersshallbesettothefollowingvalues,andconfigurationshallbeadaptedtothenewvaluesofconfigurationparameters:ORIG=F,COMM=F,D-ATT=F,U-ATT=F.6.1.2.1.8TERMINATIONREQUESTED(U5)TheMS(whichassumestobetheoriginatorofthegroupcall)hasbeeninstateU1orU2andhassentaTERMINATIONREQUESTmessagetothenetwork.Whenenteringthestate,parametersshallbesettothefollowingvalues,andconfigurationshallbeadaptedtothenewvaluesofconfigurationparameters:ORIG=T,COMM=T,D-ATT=T,U-ATT=T.6.1.2.1.9Sub-statesoftheGroupcallactivestateNOTE:Controloftheuserconnectionattachmentisseenasagroupcallcontrolfunction.Thisisareasonwhythesub-statesaredistinguished.6.1.2.1.9.1separatelink(U2sl)AdedicatedonetooneRRconnectionexistsbetweenMSandnetwork.Whenenteringthesub-state,parametersshallbesettothefollowingvalues,andconfigurationshallbeadaptedtothenewvaluesofconfigurationparameters:COMM=T,D-ATT=T,U-ATT=T.6.1.2.1.9.2waitforreceivemode(U2wr)TheMShasaskedthenetworktoenterreceivemodebutadedicatedone-to-onechannelisstillassigned.Whenenteringthesub-state,parametersshallbesettothefollowingvalues,andconfigurationshallbeadaptedtothenewvaluesofconfigurationparameters:COMM=T,D-ATT=T,U-ATT=F.6.1.2.1.9.3receivemode(U2r)TheMSusesagroupcallchannel.Whenenteringthesub-state,parametersshallbesettothefollowingvalues,andconfigurationshallbeadaptedtothenewvaluesofconfigurationparameters:COMM=F,D-ATT=T,U-ATT=F.SIST EN 300 948 V7.1.1:2003

ETSIETSIEN300948V7.1.1(2000-04)12(GSM04.68version7.1.1Release1998)6.1.2.1.9.4waitforsendandreceivemode(U2ws)TheMS(whichwasinU2rorU2wr)hasaskedfortheuplink.Whenenteringthesub-state,parametersshallbesettothefollowingvalues,andconfigurationshallbeadaptedtothenewvaluesofconfigurationparameters:COMM=F,D-ATT=T,U-ATT=T.6.1.2.1.9.5sendandreceivemode(U2sr)TheMShasbeeninformedbyitspeerentitythattheuplinkisgranted.Whenenteringthesub-state,parametersshallbesettothefollowingvalues,andconfigurationshallbeadaptedtothenewvaluesofconfigurationparameters:D-ATT=T,U-ATT=T.6.1.2.1.9.6nochannel(U2nc)TheGCCentityhasbeeninformedthatnochanneliscurrentlyavailable.TimerTnochannellisrunning.Whenenteringthesub-state,parametersshallbesettothefollowingvalues,andconfigurationshallbeadaptedtothenewvaluesofconfigurationparameters:COMM=F,D-ATT=T,U-ATT=T.6.1.2.1.10GCCTimersintheMSTable6.1specifiesthetimersusedinGCC.Thedenotationofcolumnsisdefinedasfollows:timer::=nameofthetimer;set::=underwhichconditionsthetimerisset(i.e.,started);stopped::=underwhichconditionsthetimerisstopped;runninginstate(s)::=inwhichstate(s)thetimermayberunning;actionatexpiry::=whichactionstheGCCentityshallperformatexpiry;value::=thedurationbetweensettingthetimerandexpiryofthetimer("s"denotes"second(s)""xx-yy"meansthatanyvaluebetweenxxandyyispermitted).Table6.1:SpecificationoftimersusedinGCCtimersetstoppedrunninginstate(s)actionatexpiryvalueTnochannelwhenenteringU2ncwhenleavingU2ncU2ncseesubclause6.3.13sTMM-estwhenenteringU0.pusingtheset-upprocedurewhenenteringU1usingtheimmediateset-upprocedurewhenleavingU0.porU1U0.p,U1seesubclause6.2.15sTtermwhensendingaTERMINATIONREQUESTwhenreceivingaTERMINATIONorTERMINATIONREJECTU5abortgroupcall10sTconnreqwhenenteringstateU4whenleavingstateU4U4abortgroupcall10-30s6.1.2.1.11ConsistencyofparametersandstatesTheMSshallconsiderthefollowingparametervaluesasinconsistentwiththestateorsub-state:ORIG=TisinconsistentwithstatesU3andU4.COMM=TisinconsistentwithstatesU0,U3,U4,andwithsub-statesU2ncandU2rofstateU2.SIST EN 300 948 V7.1.1:2003

ETSI13ETSIEN300948V7.1.1(2000-04)(GSM04.68version7.1.1Release1998)AllothervaluesofparametersORIG,COMM,D-ATT,andU-ATTshallnotbeconsideredbytheMSasinconsistentwithastateorsub-state.6.1.2.2Groupcallcontrolstatesatthenetworksideoftheinterface6.1.2.2.1NULL(StateN0)NogroupcallexistsfortheGCCentity.6.1.2.2.2GROUPCALLINITIATED(N1)TheGCCentityhasreceivedtheindicationthatapeerentityinaMSwantstoestablishagroupcallforacertaingroupidentity.6.1.2.2.3GROUPCALLACTIVE(N2)Thegroupcallisestablishedinatleastonecell;theremaybeaMSwhichhasseizedtheuplinkornot;theremaybetalkingdispatchersornot.6.1.2.2.4GROUPCALLESTABLISHMENTPROCEEDING(N3)TheGCCentitywantstoacceptthegroupcall,hasinitiatedestablishmentofcorrespondinggroupcallchannels,and,ifthereisacallinguser.hassentaCONNECTmessagetothecallinguser(ifthereisacallinguser).6.1.2.2.5TERMINATIONREQUESTED(N4)TheGCCentityhasaskedlowersub-layerstoterminatethegroupcallinallcellsandwaitsforaconfirmationthatthegroupcallhasbeenterminatedinallcells.6.2Proceduresforestablishmentofagroupcall6.2.1ActivationofagroupcallbythenetworkTheGCCentityinthenetworkmayinitiatetheactivationofagroupcallwithacertaingroupcallreferenceandpriorityinalistofcellsbyaskinglowerlayerstoestablishthegroupcallwiththatgroupcallreferenceandpriorityinthosecells.Itthenwaitsuntilitisinformedbylower(sub-)layersthatresourceactivationwassufficientlysuccessful,andentersstateN2,GCA
...