SIST EN 300 911 V7.4.1:2003

• Abstract:

  05.08; s31b; CR: A251; R98; 7.3.1; 7.4.0; Correction to mapping of interference levels

• 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 300 911 V7.4.1 (2000-10) - Digital cellular telecommunications system (Phase 2+) (GSM); Radio subsystem link control (GSM 05.08 version 7.4.1 Release 1998)

Overview

SIST EN 300 911 V7.4.1:2003 specifies the radio subsystem link control for the digital cellular telecommunications system (Phase 2+) known as GSM, covering both GSM900 and DCS1800 frequency bands. Developed by the Slovenski inštitut za standardizacijo (SIST) and harmonized with EN 300 911, this standard outlines essential procedures and protocols for effective radio link management within GSM networks. It plays a critical role in ensuring reliable communications, seamless handovers, and optimal network performance for mobile users.

Key Topics

The standard addresses several crucial areas of the GSM radio subsystem:

• Handover Control: Procedures for transferring ongoing calls and data sessions between cells to maintain connection continuity as users move.
• Radio Frequency (RF) Power Control: Mechanisms for adjusting transmission power levels both at the Mobile Station (MS) and Base Station System (BSS) to minimize interference and improve efficiency.
• Radio Link Failure Management: Criteria and actions for detecting loss of radio connectivity or unacceptable interference, including procedures for call re-establishment or release.
• Cell Selection and Reselection: Guidelines for mobile devices to select and camp on the most suitable cell, ensuring robust network access in idle mode, group receive mode, and during GPRS operation.
• Cordless Telephony System (CTS) Tasks: Procedures specific to GSM’s cordless telephony, such as synchronization, cell selection, and intra-cell handover.

The standard also provides detailed processes for measurement and reporting between MS and BSS, encompassing parameters like received signal strength, interference levels, and quality metrics.

Applications

SIST EN 300 911 V7.4.1:2003 is foundational for:

• Mobile Network Operators: Implementing reliable handover and power control algorithms to enhance coverage, reduce dropped calls, and efficiently allocate resources as users move within the network.
• Equipment Manufacturers: Designing GSM-compliant mobile devices, base stations, and network infrastructure with robust radio link management capabilities.
• System Integrators: Ensuring interoperability between network components from different vendors and optimizing radio performance according to standardized criteria.
• Testing and Certification Bodies: Providing a basis for assessing conformity of GSM hardware and software to essential requirements for radio subsystem behavior.
• Network Optimization: Using measurement and reporting guidelines to inform radio planning, troubleshoot connectivity issues, and adapt dynamically to network conditions.

The radio subsystem link control processes defined in this standard are vital for seamless mobility (handover), network scalability, and maintaining consistent Quality of Service (QoS) in GSM systems.

Related Standards

SIST EN 300 911 V7.4.1:2003 references and complements several other core GSM standards, including:

• GSM 05.05: Radio transmission and reception
• GSM 03.09: Handover procedures
• GSM 03.22: Idle mode and group receive functions
• GSM 04.08: Mobile radio interface Layer 3 specification
• GSM 05.02: Multiplexing and multiple access on the radio path
• GSM 05.10: Radio subsystem synchronization
• GSM 03.64: GPRS radio interface description
• GSM 11.10: MS conformity specification

Adherence to these interconnected GSM standards ensures comprehensive specification and support for digital cellular telecommunications services, underpinning the evolution and expansion of mobile networks globally.

Keywords: GSM standard, radio link control, handover, RF power control, cell reselection, interference management, SIST, ETSI, mobile network, digital cellular telecommunications system, GPRS.

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Digital cellular telecommunications system (Phase 2+) (GSM); Radio subsystem link control (GSM 05.08 version 7.4.1 Release 1998)33.070.50Globalni sistem za mobilno telekomunikacijo (GSM)Global System for Mobile Communication (GSM)ICS:Ta slovenski standard je istoveten z:EN 300 911 Version 7.4.1SIST EN 300 911 V7.4.1:2003en01-december-2003SIST EN 300 911 V7.4.1:2003SLOVENSKI
STANDARD
ETSIEN300911V7.4.1(2000-10)EuropeanStandard(Telecommunicationsseries)Digitalcellulartelecommunicationssystem(Phase2+);Radiosubsystemlinkcontrol(GSM05.08version7.4.1Release1998)GLOBALSYSTEMFORMOBILECOMMUNICATIONSRSIST EN 300 911 V7.4.1:2003

ETSIETSIEN300911V7.4.1(2000-10)2(GSM05.08version7.4.1Release1998)ReferenceREN/SMG-020508Q7R2KeywordsDigitalcellulartelecommunicationssystem,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 300 911 V7.4.1:2003

ETSIETSIEN300911V7.4.1(2000-10)3(GSM05.08version7.4.1Release1998)ContentsIntellectualPropertyRights.6Foreword.61Scope.71.1References.71.2Abbreviations.82General.83Handover.93.1Overallprocess.93.2MSmeasurementprocedure.93.3BSSmeasurementprocedure.93.4Strategy.94RFpowercontrol.104.1Overallprocess.104.2MSimplementation.104.3MSpowercontrolrange.104.4BSSimplementation.114.5BSSpowercontrolrange.114.6Strategy.114.7Timing.114.8Dedicatedchannelsusedforavoicegroupcallorvoicebroadcast.115Radiolinkfailure.125.1Criterion.125.2MSprocedure.125.3BSSprocedure.126Idlemodetasks.136.1Introduction.136.2Measurementsfornormalcellselection.136.3Measurementsforstoredlistcellselection.146.4Criteriaforcellselectionandreselection.146.5Downlinksignallingfailure.156.6MeasurementsforCellReselection.166.6.1MonitoringofreceivedsignallevelandBCCHdata.166.6.2Pathlosscriteriaandtimingsforcellre-selection.176.6.3CellreselectionalgorithmforSoLSA.186.7ReleaseofTCHandSDCCH.186.7.1Normalcase.186.7.2Callre-establishment.196.8Abnormalcasesandemergencycalls.197Networkpre-requisites.207.1BCCHcarriers.207.2IdentificationofsurroundingBSSforhandovermeasurements.208Radiolinkmeasurements.218.1Signallevel.218.1.1General.218.1.2Physicalparameter.218.1.3Statisticalparameters.228.1.4Rangeofparameter.238.2Signalquality.238.2.1General.238.2.2Physicalparameter.238.2.3Statisticalparameters.23SIST EN 300 911 V7.4.1:2003

ETSIETSIEN300911V7.4.1(2000-10)4(GSM05.08version7.4.1Release1998)8.2.4Rangeofparameter.238.3Aspectsofdiscontinuoustransmission(DTX).248.4Measurementreporting.258.4.1MeasurementreportingfortheMSonaTCH.258.4.2MeasurementreportingfortheMSonaSDCCH.268.4.3AdditionalcellreportingrequirementsformultibandMS.268.4.4CommonaspectsfortheMSonaTCHoraSDCCH.278.4.5MeasurementreportingfortheBSS.278.4.6Extendedmeasurementreporting.288.5AbsoluteMS-BTSdistance.288.5.1General.288.5.2Physicalparameter.289Controlparameters.2910GPRSmodetasks.3110.1CellRe-selection.3110.1.1MonitoringthereceivedsignallevelandPBCCHdata.3110.1.1.1Packetidlemode.3110.1.1.2Packettransfermode.3210.1.2CellRe-selectionCriteria.3310.1.3CellRe-selectionAlgorithm.3410.1.3.1Abnormalcellreselection.3510.1.4NetworkcontrolledCellre-selection.3510.1.4.1Measurementreporting.3610.1.4.2Cellre-selectioncommand.3610.1.4.3Exceptionalcases.3710.1.5ExtendedMeasurementreporting.3710.2RFPowerControl.3810.2.1MSoutputpower.3810.2.2BTSoutputpower.3910.2.3MeasurementsatMSside.4010.2.3.1DerivingtheCvalue.4110.2.3.1.1Packetidlemode.4110.2.3.1.2Packettransfermode.4110.2.3.2DerivationofChannelQualityReport.4210.2.3.2.1Packettransfermode.4310.2.3.2.2Packetidlemode.4410.2.3.2.3Measurementreporting.4510.2.4MeasurementsatBSSside.4510.3Measurementrequirements.4510.4Controlparameters.4611CTSmodetasks.4811.1CTSidlemodetasks.4811.1.1CTScellselection.4811.1.1.1SynchronizationandmeasurementsforCTScellselection.4811.1.1.2InitialsychronizationofCTS-MS.4811.1.2CriterionforCTScellselection.4911.1.3MonitoringofCTSBCHandCTSPCH.4911.1.3.1Monitoringofreceivedsignallevel.4911.1.3.2Downlinkbeaconfailure.4911.1.3.3Downlinkpagingfailure.4911.1.4ProcedureswithreportingtotheCTS-FP.5011.1.4.1AFAmonitoring.5011.1.4.2BCCHdetection.5011.1.4.3ObservedFrequencyOffset(OFO)measurement.5011.2Intra-cellhandover.5111.2.1Overallprocess.5111.2.2CTS-MSmeasurementprocedure.5111.2.3CTS-FPmeasurementprocedure.5111.2.4Strategy.5111.3RFpowercontrol.51SIST EN 300 911 V7.4.1:2003

ETSIETSIEN300911V7.4.1(2000-10)5(GSM05.08version7.4.1Release1998)11.3.1Overallprocess.5111.3.2CTS-MSimplementation.5111.3.3CTS-MSpowercontrolrange.5211.3.4CTS-FPimplementation.5211.3.5CTS-FPpowercontrolrange.5211.3.6Strategy.5211.3.7Timing.5211.4Radiolinkfailure.5311.4.1Criterion.5311.4.2CTS-MSprocedure.5311.4.3CTS-FPprocedure.5311.5Radiolinkmeasurements.5311.5.1Signalstrength.5311.5.1.1General.5311.5.1.2Physicalparameter.5411.5.1.3Statisticalparameters.5411.5.1.4Rangeofparameter.5411.5.2Signalquality.5411.5.2.1General.5411.5.2.2Physicalparameter.5411.5.2.3Statisticalparameters.5411.5.2.4Rangeofparameter.5411.5.3Aspectsofdiscontinuoustransmission(DTX).5411.5.4MeasurementreportingfortheCTS-MSonaTCH.5411.6ControlofCTS-FPservicerange.5511.7Controlparameters.55AnnexA(informative):DefinitionofabasicGSMorDCS1800handoverandRFpowercontrolalgorithm.57A.1Scope.57A.2Functionalrequirement.57A.3BSSpre-processingandthresholdcomparisons.58A.3.1Measurementaveragingprocess.58A.3.2Thresholdcomparisonprocess.59A.3.2.1RFpowercontrolprocess.59A.3.2.2HandoverProcess.60A.4BSSdecisionalgorithm.61A.4.1Internalintracellhandoveraccordingtoradiocriteria:(Interferenceproblems).62A.4.2Internalhandoveraccordingtoothercriteria.62A.4.3Generalconsiderations.62A.5Channelallocation.62A.6HandoverdecisionalgorithmintheMSC.63AnnexB(informative):PowerControlProcedures.65B.1Openloopcontrol.65B.2Closedloopcontrol.66B.3Qualitybasedcontrol.66B.4BTSpowercontrol.67B.5Example.67AnnexC(informative):Changecontrolhistory.69History.71SIST EN 300 911 V7.4.1:2003

ETSIETSIEN300911V7.4.1(2000-10)6(GSM05.08version7.4.1Release1998)IntellectualPropertyRightsIPRsessentialorpotentiallyessentialtothepresentdocumentmayhavebeendeclaredtoETSI.TheinformationpertainingtotheseessentialIPRs,ifany,ispubliclyavailableforETSImembersandnon-members,andcanbefoundinETSISR000314:"IntellectualPropertyRights(IPRs);Essential,orpotentiallyEssential,IPRsnotifiedtoETSIinrespectofETSIstandards",whichisavailablefromtheETSISecretariat.LatestupdatesareavailableontheETSIWebserver(http://www.etsi.org/ipr).PursuanttotheETSIIPRPolicy,noinvestigation,includingIPRsearches,hasbeencarriedoutbyETSI.NoguaranteecanbegivenastotheexistenceofotherIPRsnotreferencedinETSISR000314(ortheupdatesontheETSIWebserver)whichare,ormaybe,ormaybecome,essentialtothepresentdocument.ForewordThisEuropeanStandard(Telecommunicationsseries)hasbeenproducedbyETSITechnicalCommitteeSpecialMobileGroup(SMG).ThepresentdocumentspecifiestheRadiosub-systemlinkcontrolimplementedintheMobileStation(MS),BaseStationSystem(BSS)andMobileSwitchingCentre(MSC)ofthedigitalmobilecellularandpersonalcommunicationsystemsoperatinginthe900MHzand1800MHzband(GSM900andDCS1800).ThecontentsofthepresentdocumentmaybesubjecttocontinuingworkwithinSMGandmaychangefollowingformalSMGapproval.ShouldSMGmodifythecontentsofthepresentdocumentitwillthenbere-submittedforformalapprovalproceduresbyETSIwithanidentifyingchangeofreleasedateandanincreaseinversionnumberasfollows:Version7.x.ywhere:7GSMPhase2+Release1998xtheseconddigitisincrementedforchangesofsubstance,i.e.technicalenhancements,corrections,updates,etc.;ythethirddigitisincrementedwheneditorialonlychangeshavebeenincorporatedinthespecification.NationaltranspositiondatesDateofadoptionofthepresentdocument:29September2000Dateoflatestannouncementofthepresentdocument(doa):31December2000DateoflatestpublicationofnewNationalStandardorendorsementofthepresentdocument(dop/e):30June2001DateofwithdrawalofanyconflictingNationalStandard(dow):30June2001SIST EN 300 911 V7.4.1:2003

ETSIETSIEN300911V7.4.1(2000-10)7(GSM05.08version7.4.1Release1998)1ScopeThepresentdocumentspecifiestheRadiosub-systemlinkcontrolimplementedintheMobileStation(MS),BaseStationSystem(BSS)andMobileSwitchingCentre(MSC)oftheGSM,DCS1800andPCS1900systems.Unlessotherwisespecified,referencestoGSMalsoincludeDCS1800.1.1ReferencesThefollowingdocumentscontainprovisionswhich,throughreferenceinthistext,constituteprovisionsofthepresentdocument.• Referencesareeitherspecific(identifiedbydateofpublication,editionnumber,versionnumber,etc.)ornon-specific.• Foraspecificreference,subsequentrevisionsdonotapply.• Foranon-specificreference,thelatestversionapplies.• Anon-specificreferencetoanETSshallalsobetakentorefertolaterversionspublishedasanENwiththesamenumber.• ForthisRelease1998document,referencestoGSMdocumentsareforRelease1998versions(version7.x.y).[1]GSM01.04:"Digitalcellulartelecommunicationssystem(Phase2+);Abbreviationsandacronyms".[2]GSM03.03:"Digitalcellulartelecommunicationssystem(Phase2+);Numbering,addressingandidentification".[3]GSM03.09:"Digitalcellulartelecommunicationssystem(Phase2+);Handoverprocedures".[4]GSM03.22:"Digitalcellulartelecommunicationssystem(Phase2+);FunctionsrelatedtoMobileStation(MS)inidlemodeandgroupreceivemode".[5]GSM04.04:"Digitalcellulartelecommunicationssystem(Phase2+);Layer1;Generalrequirements".[6]GSM04.06:"Digitalcellulartelecommunicationssystem(Phase2+);MobileStation-BaseStationSystem(MS-BSS)interface;DataLink(DL)layerspecification".[7]GSM04.08:"Digitalcellulartelecommunicationssystem(Phase2+);Mobileradiointerfacelayer3specification".[8]GSM05.02:"Digitalcellulartelecommunicationssystem(Phase2+);Multiplexingandmultipleaccessontheradiopath".[9]GSM05.05:"Digitalcellulartelecommunicationssystem(Phase2+);Radiotransmissionandreception".[10]GSM05.10:"Digitalcellulartelecommunicationssystem(Phase2+);Radiosubsystemsynchronization".[11]GSM06.11:"Digitalcellulartelecommunicationssystem;Fullratespeech;Substitutionandmutingoflostframesforfullratespeechchannels".[12]GSM08.08:"Digitalcellulartelecommunicationssystem(Phase2+);Mobile-servicesSwitchingCentre-BaseStationSystem(MSC-BSS)interface,Layer3specification".[13]GSM08.58:"Digitalcellulartelecommunicationssystem(Phase2+);BaseStationController-BaseTransceiverStation(BSC-BTS)interface;Layer3specification".SIST EN 300 911 V7.4.1:2003

ETSIETSIEN300911V7.4.1(2000-10)8(GSM05.08version7.4.1Release1998)[14]GSM11.10:"Digitalcellulartelecommunicationssystem(Phase2+);MobileStation(MS)conformityspecification".[15]GSM03.64:"Digitalcellulartelecommunicationssystem(Phase2+);GeneralPacketRadioService(GPRS);OveralldescriptionoftheGPRSRadioInterface;Stage2".[16]GSM03.52:"Digitalcellulartelecommunicationssystem(Phase2+);GSMCordlessTelephonySystem(CTS),Phase1;LowerlayersoftheCTSRadioInterface;Stage2".[17]GSM04.56:"Digitalcellulartelecommunicationssystem(Phase2+);GSMCordlessTelephonySystem(CTS),Phase1;CTSradiointerfacelayer3specification".[18]GSM05.56:"Digitalcellulartelecommunicationssystem(Phase2+);GSMCordlessTelephonySystem(CTS),Phase1;CTS-FPradiosubsystem".1.2AbbreviationsAbbreviationsusedinthepresentdocumentarelistedinGSM01.04.2GeneralTheradiosub-systemlinkcontrolaspectsthatareaddressedareasfollows:-Handover;-RFPowercontrol;-RadiolinkFailure;-Cellselectionandre-selectioninIdlemode,inGroupReceivemodeandinGPRSmode(seeGSM03.22);-CTSmodetasks.HandoverisrequiredtomaintainacallinprogressasaMSengagedinapoint-to-pointcallorwithaccesstotheuplinkofachannelusedforavoicegroupcallpassesfromonecellcoverageareatoanotherandmayalsobeemployedtomeetnetworkmanagementrequirements,e.g.reliefofcongestion.HandovermayoccurduringacallfromoneTCHormultipleTCHs(inthecaseofmultislotconfiguration)toanotherTCHormultipleTCHs.ItmayalsooccurfromDCCHtoDCCHorfromDCCHtooneormultipleTCH(s),e.g.duringtheinitialsignallingperiodatcallset-up.Thehandovermaybeeitherfromchannel(s)ononecelltootherchannel(s)onasurroundingcell,orbetweenchannelsonthesamecellwhicharecarriedonthesamefrequencyband.Examplesaregivenofhandoverstrategies,however,thesewillbedeterminedindetailbythenetworkoperator.ForamultibandMS,specifiedinGSM02.06,thehandoverdescribedisalsoallowedbetweenanychannelsondifferentcellswhicharecarriedondifferentfrequencybands,e.g.betweenaGSM900/TCHandaDCS1800/TCH.Handoverbetweentwoco-locatedcells,carriedondifferentfrequencybands,isconsideredasinter-cellhandoverirrespectiveofthehandoverproceduresused.AdaptivecontroloftheRFtransmitpowerfromanMSandoptionallyfromtheBSSisimplementedinordertooptimizetheuplinkanddownlinkperformanceandminimizetheeffectsofco-channelinterferenceinthesystem.Thecriteriafordeterminingradiolinkfailurearespecifiedinordertoensurethatcallswhichfaileitherfromlossofradiocoverageorunacceptableinterferencearesatisfactorilyhandledbythenetwork.Radiolinkfailuremayresultineitherre-establishmentorreleaseofthecallinprogress.Forchannelsusedforavoicegroupcall,anradiouplinkfailureresultsinthefreeingupoftheuplink.Proceduresforcellselectionandre-selectionwhilstinIdlemode(i.e.notactivelyprocessingacall),arespecifiedinordertoensurethatamobileiscampedonacellwithwhichitcanreliablycommunicateonboththeradiouplinkanddownlink.TheoperationsofanMSinIdleModearespecifiedinGSM03.22.SIST EN 300 911 V7.4.1:2003

ETSIETSIEN300911V7.4.1(2000-10)9(GSM05.08version7.4.1Release1998)Cellre-selectionisalsoperformedbytheMSwhenattachedtoGPRS,exceptwhentheMSsimultaneouslyhasacircuitswitchedconnection.Optionalproceduresarealsospecifiedfornetworkcontrolledcellre-selectionforGPRS.Cellre-selectionforGPRSisdefinedinsubclause10.1.AnMSlisteningtoavoicegroupcalloravoicebroadcastusecellre-selectionprocedurestochangecell.Thismaybesupportedbyalistofcellscarryingthevoicegrouporvoicebroadcastcalldownlink,providedtotheMSbythenetwork.TheoperationsofanMSinGroupReceiveModearespecifiedinGSM03.22.InformationsignalledbetweentheMSandBSSissummarizedintables1,2and3.AfullspecificationoftheLayer1headerisgiveninGSM04.04,andoftheLayer3fieldsinGSM04.08.ForCTS,informationsignalledbetweentheCTS-MSandCTS-FPissummarizedintables4,5and6.AfullspecificationoftheCTSLayer3fieldsisgiveninGSM04.56.3Handover3.1OverallprocessTheoverallhandoverprocessisimplementedintheMS,BSSandMSC.Measurementofradiosubsystemdownlinkperformanceandsignallevelsreceivedfromsurroundingcells,ismadeintheMS.ThesemeasurementsaresignalledtotheBSSforassessment.TheBSSmeasurestheuplinkperformancefortheMSbeingservedandalsoassessesthesignallevelofinterferenceonitsidletrafficchannels.InitialassessmentofthemeasurementsinconjunctionwithdefinedthresholdsandhandoverstrategymaybeperformedintheBSS.AssessmentrequiringmeasurementresultsfromotherBTSorotherinformationresidentintheMSC,maybeperformedintheMSC.GSM03.09describesthehandoverprocedurestobeusedinPLMNs.3.2MSmeasurementprocedureAprocedureshallbeimplementedintheMSbywhichitmonitorsthedownlinkRXsignallevelandqualityfromitsservingcellandthedownlinkRXsignallevelandBSICofsurroundingBTS.ThemethodofidentificationofsurroundingBTSisdescribedinsubclause7.2.TherequirementsfortheMSmeasurementsaregiveninsubclause8.1.3.3BSSmeasurementprocedureAprocedureshallbeimplementedintheBSSbywhichitmonitorstheuplinkRXsignallevelandqualityfromeachMSbeingservedbythecell.Inthecaseofamultislotconfigurationtheevaluationshallbeperformedonatimeslotpertimeslotbasis.AprocedureshallbeimplementedbywhichtheBSSmonitorsthelevelsofinterferenceonitsidletrafficchannels.3.4StrategyThehandoverstrategyemployedbythenetworkforradiolinkcontroldeterminesthehandoverdecisionthatwillbemadebasedonthemeasurementresultsreportedbytheMS/BSSandvariousparameterssetforeachcell.Networkdirectedhandovermayalsooccurforreasonsotherthanradiolinkcontrol,e.g.tocontroltrafficdistributionbetweencells.Theexacthandoverstrategieswillbedeterminedbythenetworkoperator,adetailedexampleofabasicoverallalgorithmappearsinannexA.Possibletypesofhandoverareasfollows:Inter-cellhandover:IntercellhandoverfromtheservingcelltoasurroundingcellwillnormallyoccureitherwhenthehandovermeasurementsshowlowRXLEVand/orRXQUALonthecurrentservingcellandabetterRXLEVavailablefromasurroundingcell,orwhenasurroundingcellallowscommunicationwithalowerTXpowerlevel.ThistypicallyindicatesthatanMSisontheborderofthecellarea.IntercellhandovermayalsooccurfromtheDCCHontheservingcelltoaTCHormultislotconfigurationonanothercellduringcallestablishment.ThismaybeusedasameansofprovidingsuccessfulcallestablishmentwhennoTCHresourceisavailableonthecurrentservingcell.SIST EN 300 911 V7.4.1:2003

ETSIETSIEN300911V7.4.1(2000-10)10(GSM05.08version7.4.1Release1998)Inter-cellhandoverbetweencellsusingdifferentfrequencybandsisallowedforamultibandMS.Intra-cellhandover:Intra-cellhandoverfromonechannel/timeslotintheservingcelltoanotherchannel/timeslotinthesamecellwillnormallybeperformedifthehandovermeasurementsshowalowRXQUAL,butahighRXLEVontheservingcell.ThisindicatesadegradationofqualitycausedbyinterferenceeventhoughtheMSissituatedwithintheservingcell.Theintra-cellhandovershouldprovideachannelwithalowerlevelofinterference.Intra-cellhandovercanoccureithertoatimeslotonanewcarrierortoadifferenttimeslotonthesamecarrier.Similarly,intra-cellhandovermayoccurbetweendifferentmultislotconfigurationsinthesamecell.Thesemultislotconfigurationsmaycomprisedifferentnumberoftimeslotsandmaypartlyoverlap.Intra-cellhandoverfromoneofthebandsofoperationtoanotheroneisallowedforamultibandMS.GSM08.08definesthecausesforhandoverthatmaybesignalledfromBSStoMSC.4RFpowercontrol4.1OverallprocessRFpowercontrolisemployedtominimizethetransmitpowerrequiredbyMSorBSSwhilstmaintainingthequalityoftheradiolinks.Byminimizingthetransmitpowerlevels,interferencetoco-channelusersisreduced.4.2MSimplementationRFpowercontrolshallbeimplementedintheMS.ThepowercontrolleveltobeemployedbytheMSoneachuplinkchannel,exceptPDCH,isindicatedbymeansofthepowercontrolinformationsenteitherinthelayer1headerofeachSACCHmessageblock(seeGSM04.04)onthecorrespondingdownlinkchannel,orinadedicatedsignallingblock(seeGSM04.08).PowercontrolforPDCHisdefinedinsubclause10.2.TheMSshallemploythemostrecentlycommandedpowercontrollevelappropriatetoeachchannelforalltransmittedburstsoneitheraTCH(includinghandoveraccessburst),FACCH,SACCHorSDCCH.TheMSshallconfirmthepowercontrollevelthatitiscurrentlyemployingintheSACCHL1headeroneachuplinkchannel.TheindicatedvalueshallbethepowercontrollevelactuallyusedbythemobileforthelastburstofthepreviousSACCHperiod.Incaseofamultislotconfiguration,eachbi-directionalchannelshallbepowercontrolledindividuallybythecorrespondingSACCH.Powercontrolinformationondownlinkunidirectionalchannelsshallbeneglected.WhenaccessingacellontheRACH(randomaccess)andbeforereceivingthefirstpowercommandduringacommunicationonaDCCHorTCH(afteranIMMEDIATEASSIGNMENT),allGSMandclass1andclass2DCS1800MSshallusethepowerleveldefinedbytheMS_TXPWR_MAX_CCHparameterbroadcastontheBCCHofthecell.Theclass3DCS1800MSshallusethepowerleveldefinedbyMSTXPWRMAXCCHplusthevaluePOWEROFFSETalsobroadcastontheBCCHofthecell.IfapowercontrolleveldefinedinGSM05.05isreceivedbutthelevelisnotsupportedbytheMS,theMSshallusethesupportedoutputpowerwhichisclosesttotheoutputpowerindicatedbythereceivedpowercontrollevel.4.3MSpowercontrolrangeTherangeoverwhichaMSshallbecapableofvaryingitsRFoutputpowershallbefromitsmaximumoutputdowntoitsminimum,instepsofnominally2dB.GSM05.05givesadetaileddefinitionoftheRFpowerlevelstepsizeandtolerances.SIST EN 300 911 V7.4.1:2003

ETSIETSIEN300911V7.4.1(2000-10)11(GSM05.08version7.4.1Release1998)4.4BSSimplementationRFpowercontrolmayoptionallybeimplementedintheBSS.4.5BSSpowercontrolrangeTherangeoverwhichtheBSSshallbecapableofreducingitsRFoutputpowerfromitsmaximumlevelshallbenominally30dB,in15stepsofnominally2dB.GSM05.05givesadetaileddefinitionoftheRFpowerlevelstepsizeandtolerances.4.6StrategyTheRFpowercontrolstrategyemployedbythenetworkdeterminestheorderedpowerlevelthatissignalledtotheMS,andthepowerlevelthatisemployedbytheBSS.ThepowerleveltobeemployedineachcasewillbebasedonthemeasurementresultsreportedbytheMS/BTSandvariousparameterssetforeachcell.Theexactstrategieswillbedeterminedbythenetworkoperator.AdetailedexampleofabasicalgorithmappearsinannexA.4.7TimingUponreceiptofacommandfromanSACCHtochangeitspowerlevelonthecorrespondinguplinkchannel,theMSshallchangetothenewlevelatarateofonenominal2dBpowercontrolstepevery60ms(13TDMAframes),i.e.arangechangeof15stepsshouldtakeabout900ms.ThechangeshallcommenceatthefirstTDMAframebelongingtothenextreportingperiod(asspecifiedinsubclause8.4).TheMSshallchangethepoweronenominal2dBstepatatime,atarateofonestepevery60msfollowingtheinitialchange,irrespectiveofwhetheractualtransmissiontakesplaceornot.Incaseofchannelchange,exceptformultislotconfigurationchange,thecommandedpowercontrollevelshallbeappliedoneachnewchannelimmediately.ThemultislotconfigurationchangemessagedoesnotcommandtheMStousenewpowercontrollevels.ForthosetimeslotsnotusedbytheMSbeforethemultislotconfigurationchangeprocedure,theMSshallusethepowercontrollevelusedonthemainchannelbeforethemultislotconfigurationchange.4.8DedicatedchannelsusedforavoicegroupcallorvoicebroadcastThenetworkshallnotallocatetheuplinkofthechannelusedforavoicegroupcalltomorethanoneMS.Ifmarkedbusy,nootherMSshalltransmitonthechannel.Thismarkingisindicatedbythenetwork,asdefinedinGSM03.68and04.08.AnyMSallocatedtheuplinkofachannelusedforavoicegroupcallshallonlytransmitiftheuplinkismarkedbusy,andshallstopusingtheuplinkifithappenstobecomemarkedfree.AnMSnotallocatedtheuplinkmayperformarandomaccessprocedureontheuplinktogainaccesstotalk,onlyiftheuplinkismarkedasfree.Onachannelusedduringavoicegroupcall,theuplinkpowercontrolshallonlyapplytotheMScurrentlyallocatedthatuplink,andtheMSpowercontrollevelorderedbythenetworkshallbeignoredbyallotherMSslisteningtothedownlink.Whenperformingarandomaccessonacelltogainaccesstotheuplinkofachannelusedforavoicegroupcall,untilreceivingthefirstdedicatedpowercommandfromthenetwork,theMSshallusethelastreceivedpowerlevelcommandasdefinedbytheMS_TXPWR_MAX_CCHparameterbroadcastontheBCCHofthecell,orifMS_TXPWR_MAX_CCHcorrespondstoapowercontrollevelnotsupportedbytheMSasdefinedbyitspowerclassinGSM05.05,theMSshallactasthoughtheclosestsupportedpowercontrollevelhadbeenbroadcast.RFdownlinkpowercontrolwillnormallynotbeappliedonchannelsusedforavoicegroupcallorvoicebroadcast.SIST EN 300 911 V7.4.1:2003

ETSIETSIEN300911V7.4.1(2000-10)12(GSM05.08version7.4.1Release1998)5Radiolinkfailure5.1CriterionThecriterionfordeterminingRadioLinkFailureintheMSshallbebasedonthesuccessrateofdecodingmessagesonthedownlinkSACCH.Foracircuitswitchedmultislotconfiguration,onlythemainSACCHshallbeusedfordeterminingRadioLinkFailure.ForGPRS,RadioLinkFailureisdeterminedbytheRLC/MACprotocol(seeGSM04.60).5.2MSprocedureTheaimofdeterminingradiolinkfailureintheMSistoensurethatcallswithunacceptablevoice/dataquality,whichcannotbeimprovedeitherbyRFpowercontrolorhandover,areeitherre-establishedorreleasedinadefinedmanner.Ingeneraltheparametersthatcontroltheforcedreleaseshouldbesetsuchthattheforcedreleasewillnotnormallyoccuruntilthecallhasdegradedtoaqualitybelowthatatwhichthemajorityofsubscriberswouldhavemanuallyreleased.Thepresentdocumentsuresthat,forexample,acallontheedgeofaradiocoveragearea,althoughofbadquality,canusuallybecompletedifthesubscriberwishes.TheradiolinkfailurecriterionisbasedontheradiolinkcounterS.IftheMSisunabletodecodeaSACCHmessage(BFI=1),Sisdecreasedby1.InthecaseofasuccessfulreceptionofaSACCHmessage(BFI=0)Sisincreasedby2.InanycaseSshallnotexceedthevalueofRADIO_LINK_TIMEOUT.IfSreaches0aradiolinkfailureshallbedeclared.TheactiontobetakenisspecifiedinGSM04.08.TheRADIO_LINK_TIMEOUTparameteristransmittedbyeachBSSintheBCCHdata(seetable1).TheMSshallcontinuetransmittingasnormalontheuplinkuntilSreaches0.ThealgorithmshallstartaftertheassignmentofadedicatedchannelandSshallbeinitializedtoRADIO_LINK_TIMEOUT.Thedetailedoperationshallbeasfollows:-theradiolinktime-outalgorithmshallbestoppedatthereceptionofachannelchangecommand;-(re-)initializationandstartofthealgorithmshallbedonewhenevertheMSswitchestoanewchannel(thisincludestheoldchannelinassignmentandhandoverfailurecases),atthelatestwhenthemainsignallinglink(seeGSM04.08)hasbeenestablished;-theRADIO_LINK_TIMEOUTvalueusedat(re-)initializationshallbethatusedonthepreviouschannel(intheImmediateAssignmentcasethevaluereceivedontheBCCH),orthevaluereceivedonSACCHiftheMShasreceivedaRADIO_LINK_TIMEOUTvalueonthenewchannelbeforetheinitialization;-ifthefirstRADIO_LINK_TIMEOUTvalueontheSACCHisreceivedonthenewchannelaftertheinitialization,thecountershallbere-initializedwiththenewvalue.AnMSlisteningtoavoicegroupcalloravoice
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