SIST EN 300 912 V6.6.1:2003

• Abstract:

  SUBJECT Clarification of packet polling procedure for calculating new TA

• 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 300 912 V6.6.1 (2001-05) - Digital cellular telecommunications system (Phase 2+); Radio subsystem synchronization (GSM 05.10 version 6.6.1 Release 1997)

Overview

SIST EN 300 912 V6.6.1:2003 is a European standard focusing on the synchronization of the radio subsystem within the Digital Cellular Telecommunications System (GSM Phase 2+). Developed by the Slovenski inštitut za standardizacijo (SIST), this standard aligns with EN 300 912 (GSM 05.10 version 6.6.1 Release 1997) and defines core requirements for the timing and synchronization between Base Transceiver Stations (BTS) and Mobile Stations (MS) in GSM networks. Its scope includes the critical subject of packet polling procedures for calculating new Timing Advance (TA) values, which are central to efficient network operation and user mobility in GSM cellular environments.

Key Topics

• Radio Subsystem Synchronization: Outlines how synchronization is achieved between BTS and MS to ensure seamless communication.
• Timebase Counters: Describes the use of various counters (quarter bit, bit, timeslot, TDMA frame) that structure radio signal timings.
• Timing Advance (TA) Procedures: Focuses on how TA is determined, transmitted, and applied for both circuit-switched and packet-switched channels, enabling accurate timing compensation for propagation delays.
• Packet Polling for Timing Advance: Clarifies the packet polling process, a method used to accurately calculate and update TA during mobile station operation in packet transfer mode.
• Delay Tracking: Specifies requirements for tracking transmission delays due to mobile station movement and adjusting timing accordingly.
• Synchronization During Handovers: Addresses procedures for maintaining or recalculating TA when mobile users transfer between BTSs, supported by synchronized or pseudo-synchronized handover techniques.

Applications

The standard is crucial in supporting the following GSM network operations:

• GSM Base Station Synchronization: Guarantees that all BTS transmissions and MS responses are accurately aligned, preventing interference and ensuring the integrity of voice and data communication.
• Timing Advance Calculation and Updates: Enables the network to determine and adjust TA, essential for keeping transmissions properly aligned regardless of user location within a cell.
• Smooth Packet-switched and Circuit-switched Operations: Facilitates effective communication in both circuits (voice calls) and packet modes (GPRS data sessions), making sure the radio link is always synchronized.
• Seamless User Handover: Enhances mobile user experience by reducing dropped calls and data session interruptions when users move between cells.
• Efficient Radio Spectrum Use: By keeping user transmissions strictly within their assigned time slots, the standard supports high network capacity and minimizes cross-interference.

Related Standards

For broader or more detailed guidance, refer to these standards closely linked to the synchronization and radio transmission framework:

• GSM 05.02: Multiplexing and multiple access on the radio path
• GSM 05.05: Radio transmission and reception requirements
• GSM 05.08: Radio subsystem link control
• GSM 03.30: Radio network planning aspects
• GSM 03.60, 03.64: General Packet Radio Service (GPRS) service description and radio interface
• GSM 04.08, 04.60: Mobile radio interface protocols and RLC/MAC specifications

Practical Value

Implementing the specifications in SIST EN 300 912 V6.6.1:2003 is vital for:

• Equipment Manufacturers: Ensuring compatibility and interoperability of radio units with global GSM networks.
• Mobile Network Operators: Maintaining robust and synchronized cellular coverage, improving customer satisfaction through reliable connectivity.
• System Integrators: Designing and deploying cells with optimal timing alignment, supporting high-speed mobility and minimization of delay errors.
• Regulatory and Standardization Bodies: Enforcing harmonized protocols for GSM network performance and spectrum efficiency.

This standard guides in achieving seamless GSM radio synchronization, underlying the performance and reliability of modern cellular networks.

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Digital cellular telecommunications system (Phase 2+); Radio subsystem synchronization (GSM 05.10 version 6.6.1 Release 1997)33.070.50Globalni sistem za mobilno telekomunikacijo (GSM)Global System for Mobile Communication (GSM)ICS:Ta slovenski standard je istoveten z:EN 300 912 Version 6.6.1SIST EN 300 912 V6.6.1:2003en01-december-2003SIST EN 300 912 V6.6.1:2003SLOVENSKI
STANDARD
ETSIEN300912V6.6.1(2001-05)EuropeanStandard(Telecommunicationsseries)Digitalcellulartelecommunicationssystem(Phase2+);Radiosubsystemsynchronization(GSM05.10version6.6.1Release1997)GLOBALSYSTEMFORMOBILECOMMUNICATIONSRSIST EN 300 912 V6.6.1:2003

ETSIETSIEN300912V6.6.1(2001-05)2(GSM05.10version6.6.1Release1997)ReferenceREN/SMG-020510Q6R4KeywordsDigitalcellulartelecommunicationssystem,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.©EuropeanTelecommunicationsStandardsInstitute2001.Allrightsreserved.SIST EN 300 912 V6.6.1:2003

ETSIETSIEN300912V6.6.1(2001-05)3(GSM05.10version6.6.1Release1997)ContentsIntellectualPropertyRights.5Foreword.51Scope.61.1References.61.2Definitionsandabbreviations.62Generaldescriptionofsynchronizationsystem.73Timebasecounters.73.1Timingstateofthesignals.73.2Relationshipbetweencounters.84Timingoftransmittedsignals.85BTSRequirementsforSynchronization.85.1Frequencysource.85.2Timebasecounters.85.3InternalBTScarriertiming.85.4InitialTimingadvanceestimation.95.5Maximumtimingadvancevalue.95.6Delaytracking.95.6.1Forcircuitswitchedchannels.95.6.2Forpacketswitchedchannels.95.6.3Delayassessmenterror.95.7Timeslotlength.95.8RangeofTimingadvance.96MSRequirementsforSynchronization.106.1MScarrierfrequency.106.2Internaltimebase.106.3AssessmentofBTStiming.106.4Timingoftransmission.106.5ApplicationofTimingAdvance.106.5.1Forcircuitswitchedchannels.106.5.2Forpacketswitchedchannels.116.6AccesstoanewBTS.116.7Temporarylossofsignal.126.8Timingofintracellchannelchange.126.9ApplicationofnewTimingAdvancevalue.126.10Definitionof"readytotransmitwithinxms".126.11DefinitionofadditionalreactiontimesforGPRSmobilestations.126.11.1Uplinkanddownlinkassignmentreactiontimes.126.11.2Changeinchannelcodingschemecommandedbynetwork.126.11.3Contentionresolutionreactiontime.136.11.4Reactiontimeinresponsetoothercommandingmessages.13AnnexA(normative):Additionalrequirementsforpseudo-synchronization,synchronizedhandoversandpseudo-synchronizedhandovers.14A.1Generaldescriptionsanddefinitions.14A.1.1Conventions.14A.1.2Definitions.14A.1.3Detailsofoperations.14A.2BTSrequirements.15A.2.1Thepseudo-synchronizationscheme.15A.2.1.1BTSatimedifferenceestimate.15A.2.1.2Thereceptionepochcriterion.15SIST EN 300 912 V6.6.1:2003

ETSIETSIEN300912V6.6.1(2001-05)4(GSM05.10version6.6.1Release1997)A.2.1.3Pseudo-synchronizedhandover.15A.2.2Thesynchronizationrequirement.15A.3MSrequirements.16A.3.1Provisionoftimedifferenceinformation.16A.3.2Aftereachsuccessfulhandover.16A.3.3Synchronizedorapseudosynchronizedhandover.16AnnexB(informative):ChangeRequestHistory.17History.18SIST EN 300 912 V6.6.1:2003

ETSIETSIEN300912V6.6.1(2001-05)5(GSM05.10version6.6.1Release1997)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).ThepresentdocumentdefinestherequirementsforsynchronizationontheGSMradiosub-systemofthedigitalmobilecellularandpersonalcommunicationsystemsoperatinginthe900MHzand1800MHzband(GSM900andDCS1800).ThecontentsofthepresentdocumentaresubjecttocontinuingworkwithinSMGandmaychangefollowingformalSMGapproval.ShouldSMGmodifythecontentsofthepresentdocumentitwillthenberepublishedbyETSIwithanidentifyingchangeofreleasedateandanincreaseinversionnumberasfollows:Version6.x.ywhere:6indicatesrelease1997ofGSMPhase2+xtheseconddigitisincrementedforallchangesofsubstance,i.e.technicalenhancements,corrections,updates,etc.ythethirddigitisincrementedwheneditorialonlychangeshavebeenincorporatedinthespecification.NationaltranspositiondatesDateofadoptionofthisEN:18May2001DateoflatestannouncementofthisEN(doa):31August2001DateoflatestpublicationofnewNationalStandardorendorsementofthisEN(dop/e):28February2002DateofwithdrawalofanyconflictingNationalStandard(dow):28February2002SIST EN 300 912 V6.6.1:2003

ETSIETSIEN300912V6.6.1(2001-05)6(GSM05.10version6.6.1Release1997)1ScopeThepresentdocumentdefinestherequirementsforsynchronizationontheGSMradiosub-system.(However,itdoesnotdefinethesynchronizationalgorithmstobeusedintheBaseTransceiverStation(BTS)andMobileStation(MS).Theseareuptothemanufacturertospecify.)1.1ReferencesThefollowingdocumentscontainprovisionswhich,throughreferenceinthistext,constituteprovisionsofthepresentdocument.• Referencesareeitherspecific(identifiedbydateofpublication,editionnumber,versionnumber,etc.)ornon-specific.• Foraspecificreference,subsequentrevisionsdonotapply.• Foranon-specificreference,thelatestversionapplies.• Anon-specificreferencetoanETSshallalsobetakentorefertolaterversionspublishedasanENwiththesamenumber.• ForthisRelease1997document,referencestoGSMdocumentsareforRelease1997versions(version6.x.y).[1]GSM01.04:"Digitalcellulartelecommunicationssystem(Phase2+);Abbreviationsandacronyms".[2]GSM03.60:"Digitalcellulartelecommunicationssystem(Phase2+);GeneralPacketRadioService(GPRS);ServiceDescriptionStage2".[3]GSM03.64:"Digitalcellulartelecommunicationssystem(Phase2+);GeneralPacketRadioService(GPRS);GPRSRadioInterfaceStage2".[4]GSM04.08:"Digitalcellulartelecommunicationssystem(Phase2+);Mobileradiointerfacelayer3specification".[5]GSM04.60:"Digitalcellulartelecommunicationssystem(Phase2+);GeneralPacketRadioService(GPRS);MobileStation(MS)-BaseStationSystem(BSSinterface;RadioLinkControl(RLC)andMediumAccessControl(MAC)LayerSpecification".[6]GSM05.02:"Digitalcellulartelecommunicationssystem(Phase2+);Multiplexingandmultipleaccessontheradiopath".[7]GSM05.05:"Digitalcellulartelecommunicationssystem(Phase2+);Radiotransmissionandreception".[8]GSM05.08:"Digitalcellulartelecommunicationssystem(Phase2+);Radiosubsystemlinkcontrol".[9]GSM03.30:"Digitalcellulartelecommunicationssystem(Phase2+);Radionetworkplanningaspects".1.2DefinitionsandabbreviationsInadditiontothosebelow,abbreviationsusedinthepresentdocumentarelistedinGSM01.04.Forthepurposesofthepresentdocument,thefollowingtermsanddefinitionsapply:BTS:BaseTransceiverStationTimingAdvance:signalsentbytheBTStotheMSwhichtheMSusestoadvanceitstimingsoftransmissionstotheBTSsoastocompensateforpropagationdelaySIST EN 300 912 V6.6.1:2003

ETSIETSIEN300912V6.6.1(2001-05)7(GSM05.10version6.6.1Release1997)Quarterbitnumber:timingofquarterbitperiods(12/13µs)withinatimeslotTimeslotnumber:timingoftimeslotswithinaTDMAframeTDMAframenumber:countofTDMAframesrelativetoanarbitrarystartpointCurrentServingBTS:BTSononeofwhosechannels(TCH,DCCH,CCCHorPDCH)theMSiscurrentlyoperatingTimebasecounters:setofcounterswhichdeterminethetimingstateofsignalstransmittedbyaBTSorMSMStimingoffset:delayofthereceivedsignalrelativetotheexpectedsignalfromanMSatzerodistanceunderstaticchannelconditionswithzerotimingadvance.Thisisaccurateto±1bit,andreportedonceperSACCHorafteraRACHas.required(i.e.atthesamerateastimingadvance).Forexample,foranMSwitharoundtrippropagationdelayofPbits,butwithatimingadvanceofTbits,thereportedtimingoffsetwillbeP-Tquantizedtothenearestbit.ForGPRStheMStimingoffsetisnotreportedTimingAdvanceIndex:TimingAdvanceIndexTAIusedforGPRS,whichdeterminesthepositionofthesubchannelonPTCCH(seeGSM05.02)usedbytheMStosendanaccessburst,fromwhichthenetworkcanderivethetimingadvance2GeneraldescriptionofsynchronizationsystemThisclausegivesageneraldescriptionofthesynchronizationsystem.Detailedrequirementsaregiveninclauses3to6.TheBTSsendssignalsontheBCCHtoenabletheMStosynchronizeitselftotheBTSandifnecessarycorrectitsfrequencystandardtobeinlinewiththatoftheBTS.ThesignalssentbytheBTSforthesepurposesare:a)frequencycorrectionbursts;b)synchronizationbursts.Thetimingsoftimeslots,TDMAframes,TCHframesandcontrolchannelframesareallrelatedtoacommonsetofcounterswhichruncontinuouslywhethertheMSandBTSaretransmittingornot.Thus,oncetheMShasdeterminedthecorrectsettingofthesecounters,allitsprocessesaresynchronizedtothecurrentservingBTS.TheMStimesitstransmissionstotheBTSinlinewiththosereceivedfromtheBTS.TheBTSsendstoeachMSa"timingadvance"parameter(TA)accordingtotheperceivedroundtrippropagationdelayBTS-MS-BTS.TheMSadvancesitstimingbythisamount,withtheresultthatsignalsfromdifferentMS'sarrivingattheBTSandcompensatedforpropagationdelay.Thisprocessiscalled"adaptiveframealignment".Additionally,synchronizationfunctionsmaybeimplementedinboththeMSandtheBTStosupporttheso-calledpseudosynchronizationscheme.ThesupportofthisschemeisoptionalexceptthatMSshallmeasureandreporttheObservedTimingDifference(OTD),whichisamandatoryrequirement.Thedetailedspecificationsofthepseudo-synchronizationschemeareincludedinannexA.3Timebasecounters3.1TimingstateofthesignalsThetimingstateofthesignalstransmittedbyaBTSorMSisdefinedbythefollowingcounters:-QuarterbitnumberQN(0-624)-BitnumberBN(0-156);-TimeslotnumberTN(0-7);-TDMAframenumberFN(0to(26x51x2048)-1=2715647).SIST EN 300 912 V6.6.1:2003

ETSIETSIEN300912V6.6.1(2001-05)8(GSM05.10version6.6.1Release1997)3.2RelationshipbetweencountersTherelationshipbetweenthesecountersisasfollows:-QNincrementsevery12/13µs;-BN=IntegerpartofQN/4;-TNincrementswheneverQNchangesfromcount624to0;-FNincrementswheneverTNchangesfromcount7to0.4TimingoftransmittedsignalsThetimingofsignalstransmittedbytheMSandBTSaredefinedinGSM05.02.TheMScanusethetimingofreceiptofthesynchronizationbursttosetupitstimebasecountersasfollows:QNissetbythetimingofthetrainingsequence;TN=0whenthesynchburstisreceived;FN=51((T3-T2)mod(26))+T3+51x26xT1whenthesynchburstisreceived,(whereT3=(10xT3')+1,T1,T2andT3'beingcontainedininformationfieldsinsynchronizationburst).Thereafter,thetimebasecountersareincrementedasinclause3.2.(WhenadjacentBTS'sarebeingmonitoredforhandoverpurposes,orforcellreselectionpurposesingroupreceivemode,theMSmaychoosetostorethevaluesofQN,TNandFNforalltheBTS'swhosesynchronizationburstshavebeendetectedrelativetoQN,TNandFNforitscurrentservingBTS.)5BTSRequirementsforSynchronizationTheconditionsunderwhichtherequirementsofclauses5.4and5.6mustbemetshallbe3dBbelowthereferencesensitivitylevelinGSM05.05and3dBlesscarriertointerferenceratiothanthereferenceinterferenceratiosinGSM05.05.5.1FrequencysourceTheBTSshalluseasinglefrequencysourceofabsoluteaccuracybetterthan0,05ppmforbothRFfrequencygenerationandclockingthetimebase.ThesamesourceshallbeusedforallcarriersoftheBTS.5.2TimebasecountersItisoptionalwhetherthetimebasecountersofdifferentBTS'saresynchronizedtogether.5.3InternalBTScarriertimingThechannelsofdifferentcarrierstransmittedbyaBTSshallbesynchronizedtogether,i.e.controlledbythesamesetofcounters.Thetimingdifferencebetweenthedifferentcarriersshallbelessthan1/4bitperiods,measuredattheBTSantenna.SIST EN 300 912 V6.6.1:2003

ETSIETSIEN300912V6.6.1(2001-05)9(GSM05.10version6.6.1Release1997)5.4InitialTimingadvanceestimationWhentheBTSdetectsanaccessbursttransmissiononRACHorPRACH,itshallmeasurethedelayofthissignalrelativetotheexpectedsignalfromanMSatzerodistanceunderstaticchannelconditions.Thisdelay,calledthetimingadvance,shallberoundedtothenearestbitperi
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