SIST EN 300 912 V6.6.1:2003
(Main)Digital cellular telecommunications system (Phase 2+); Radio subsystem synchronization (GSM 05.10 version 6.6.1 Release 1997)
- Abstract
SUBJECT Clarification of packet polling procedure for calculating new TA
- Status
- Published
- Publication Date
- 30-Nov-2003
- Current Stage
- 6060 - National Implementation/Publication (Adopted Project)
- Start Date
- 01-Dec-2003
- Due Date
- 01-Dec-2003
- Completion Date
- 01-Dec-2003
SIST EN 300 912 V6.6.1:2003 is the Slovenian adoption of ETSI EN 300 912 Version 6.6.1 for the GSM digital cellular telecommunications system. It specifies radio subsystem synchronization for the Base Transceiver Station (BTS) and Mobile Station (MS), including timing counters, timing advance, and handover timing. The document is aimed at GSM implementers, network engineers, and equipment makers working on GSM900 and DCS1800 systems.
What does SIST EN 300 912 V6.6.1:2003 specify?
SIST EN 300 912 V6.6.1:2003 defines synchronization requirements for the GSM radio subsystem. It sets the timing behavior for BTS and MS operation, while leaving the detailed synchronization algorithms to the manufacturer.
The document is organized into clauses 1 to 6, plus two annexes.
| Annex | What it covers |
|---|---|
| Annex A | Additional requirements for pseudo-synchronization, synchronized handovers, and pseudo-synchronized handovers |
| Annex B | Change request history |
What are the key requirements of SIST EN 300 912 V6.6.1:2003?
Clause 2 introduces the synchronization model: the BTS sends frequency correction bursts and synchronization bursts on BCCH so the MS can lock to the network timing and, if needed, correct its frequency reference. In practice, this is what lets the terminal align its clock before it transmits.
Clauses 3 and 4 define the timing counters and how they move together. The timing state uses Quarter bit number (QN), Bit number (BN), Timeslot number (TN), and TDMA frame number (FN), and the MS derives its timing from the synchronization burst. That gives both sides a common timebase for radio operation.
Clause 5 sets BTS requirements. The BTS uses a single frequency source with absolute accuracy better than 0.05 ppm for both RF generation and timebase clocking, and all carriers of the BTS use that same source. The different carriers must stay synchronized within less than a quarter bit period at the antenna, which matters for stable multi-carrier transmission.
Clause 5 also defines how the BTS estimates and tracks Timing Advance (TA). It measures the delay of access bursts on RACH or PRACH, rounds the result to the nearest bit period, limits TA to 63, and continues to track delay changes on circuit-switched and packet-switched channels. For testing, the delay assessment error has to stay below half a bit period for stationary MS, with allowance for movement up to 500 km/h.
Clause 6 gives the MS synchronization requirements. The MS carrier frequency must be accurate to within 0.1 ppm, the MS must keep its internal timebase aligned with the BTS, and it transmits according to the last received TA. For multi-slot operation, the MS uses a common timebase across channels, so timing stays consistent when several channels are active.
Clause 6.5.2 is the most relevant part for packet timing advance. In packet transfer mode, the MS uses the Timing Advance Index (TAI) on PTCCH, sends access bursts on the assigned subchannel, and applies the updated TA received from the BTS for normal burst transmission. The network may request four access bursts through a PACKET_POLLING_REQUEST to calculate a new TA, which is the packet polling procedure clarified by this standard.
Clauses 6.7 to 6.11 define reaction times and recovery behavior. The MS can ride through short total signal loss using a 0.2 ppm clock for up to 64 SACCH block periods, and it must react within defined time limits for channel changes, new TA values, GPRS assignments, and contention resolution. In practice, these limits control how quickly a terminal can keep talking after the network changes resources.
Annex A adds pseudo-synchronization and synchronized handover behavior. It uses Observed Time Difference (OTD) and Real Time Difference (RTD) so a handover can reuse timing knowledge from the previous BTS and help the new BTS estimate timing without starting from zero.
What terms does SIST EN 300 912 V6.6.1:2003 define?
- Base Transceiver Station (BTS) - the radio base station that transmits to and receives from the MS.
- Mobile Station (MS) - the mobile device or terminal that communicates with the BTS.
- Timing Advance (TA) - the value the BTS sends so the MS transmits earlier and its signal arrives on time.
- Timing Advance Index (TAI) - the GPRS timing index that selects the PTCCH subchannel used to derive TA.
- Observed Time Difference (OTD) - the timing difference between two BTSs as measured by the MS.
- Real Time Difference (RTD) - the local GSM time of one BTS minus that of another BTS.
- Timebase counters - the counters that define the timing state of BTS and MS signals.
Who uses SIST EN 300 912 V6.6.1:2003?
GSM network operators use this standard to set up timing and handover behavior in radio networks. BTS and MS designers use it to implement timing counters, frequency accuracy, timing advance, and packet transfer timing. Test labs and quality teams use it to check synchronization accuracy, delay tracking, and reaction times in GSM900 and DCS1800 equipment.
What changed in SIST EN 300 912 V6.6.1:2003 from the previous edition?
Annex B records the change request history leading to Version 6.6.1, which updates Version 6.6.0 for publication. The listed subjects include clarification of the use of TAI, renaming of GPRS RR states, missing timing advance updates on PTCCH, correction of timing advance for GPRS, packet polling procedure for calculating new TA, GPRS MS timing requirements, correction of the timing advance procedure, additional GPRS reaction times, timing advance for access bursts on PTCCH/U, reaction time after contention resolution during one phase access, and definition of other reaction times.
Which standards are used with SIST EN 300 912 V6.6.1:2003?
- GSM01.04 - supplies abbreviations and acronyms used in the document.
- GSM03.60 - provides the GPRS service description stage 2.
- GSM03.64 - provides the GPRS radio interface stage 2.
- GSM04.08 - defines the mobile radio interface layer 3 specification.
- GSM04.60 - defines the MS-BSS interface for RLC and MAC.
- GSM05.02 - covers multiplexing and multiple access on the radio path.
- GSM05.05 - covers radio transmission and reception.
- GSM05.08 - covers radio subsystem link control.
- GSM03.30 - covers radio network planning aspects.
What does the SIST EN 300 912 V6.6.1:2003 document contain?
The document contains the timing model for GSM radio synchronization, including counter relationships and the timing of transmitted signals. It also gives the procedures for initial TA estimation, continuous delay tracking, packet transfer timing advance, and the timing behavior needed when the MS changes channel or handover mode.
Annex A contains the formulas and message behavior for pseudo-synchronization and the different handover cases. Annex B contains the change request history that led to this version.
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Frequently Asked Questions
SIST EN 300 912 V6.6.1:2003 is a standard published by the Slovenian Institute for Standardization (SIST). Its full title is "Digital cellular telecommunications system (Phase 2+); Radio subsystem synchronization (GSM 05.10 version 6.6.1 Release 1997)". This standard covers: SUBJECT Clarification of packet polling procedure for calculating new TA
SUBJECT Clarification of packet polling procedure for calculating new TA
SIST EN 300 912 V6.6.1:2003 is classified under the following ICS (International Classification for Standards) categories: 33.070.50 - Global System for Mobile Communication (GSM). The ICS classification helps identify the subject area and facilitates finding related standards.
SIST EN 300 912 V6.6.1:2003 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
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.:+33492944200Fax:+33493654716SiretN°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:editor@etsi.frCopyrightNotificationNopartmaybereproducedexceptasauthorizedbywrittenpermission.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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