SIST EN 301 706 V7.1.1:2003

• Abstract:

  Adaptive Multi- Rate (AMR) Comfort noise

• 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
• Mandate: T-172
• Ref Project: ETSI EN 301 706 V7.1.1 (1999-12) - Digital cellular telecommunications system (Phase 2+) (GSM); Comfort noise aspects for Adaptive Multi-Rate (AMR) speech traffic channels (GSM 06.92 version 7.1.1 Release 1998)

SIST EN 301 706 V7.1.1:2003 is the Slovenian adoption of ETSI EN 301 706 Version 7.1.1 for the GSM Phase 2+ Adaptive Multi-Rate (AMR) speech traffic channels. It specifies how comfort noise is evaluated, encoded, signalled, decoded, and regenerated in Mobile Stations (MSs) and Base Station Systems (BSSs) during Discontinuous Transmission (DTX).

What does SIST EN 301 706 V7.1.1:2003 specify?

SIST EN 301 706 V7.1.1:2003 specifies the detailed requirements for background acoustic noise evaluation, noise parameter encoding/decoding, and comfort noise generation for AMR full rate and half rate speech traffic channels. It is organized into seven clauses and one informative annex.

• Clause 1 gives the scope and implementation obligations.
• Clause 2 lists the referenced GSM documents.
• Clause 3 defines the terms, symbols, and abbreviations used in the procedures.
• Clause 4 explains the comfort-noise problem that DTX creates and the purpose of SID frames.
• Clause 5 describes the transmit side.
• Clause 6 describes the receive side.
• Clause 7 gives computational details and bit allocation, including Table 1.
• Annex A is informative and records the document change history.

The scope is narrow and practical: it is about how the codec and radio system handle comfort noise when speech transmission pauses, so the listener does not hear abrupt noise dropouts.

What are the key requirements of SIST EN 301 706 V7.1.1:2003?

SIST EN 301 706 V7.1.1:2003 makes the comfort-noise processing mandatory for GSM MSs that support AMR full rate and half rate speech traffic channels. For BSSs, the receiver requirements are mandatory whenever AMR is supported, and the transmitter requirements apply where downlink DTX is used. That matters because it tells implementers which parts must be built and verified on each side of the link.

Transmit side

• Clause 5 requires the encoder to evaluate comfort-noise parameters from the AMR speech encoder output. The important inputs are the unquantized LP parameters and the frame energy, which means the transmitter must measure the speech spectrum and level during inactive periods.
• Clause 5.1 averages the LSF parameters over eight consecutive frames marked VAD = 0. In practice, this smooths the background-noise spectrum before it is sent in a SID frame.
• Clause 5.1 also selects a reference vector from a codebook of typical background-noise vectors, then sends the selected index and the LSF data in the SID frame. This gives the receiver a compact description of the noise shape.
• Clause 5.2 averages logarithmic frame energy over the same eight-frame window and quantizes it with a 6-bit algorithmic quantizer. That is the noise-loudness part of the description.
• Clause 5.3 changes the normal speech-encoding behaviour while a SID frame is generated: it suppresses ordinary quantization and codebook search steps that are only needed for speech. This keeps SID frames distinct from speech frames.
• Clause 5.4 states that the 35 comfort-noise bits are encoded as a SID frame, with the first SID frame handled as described in GSM05.03.

Receive side

• Clause 6 starts comfort-noise generation or update when a valid SID frame is received. The receiver therefore needs to track SID timing and not just speech frames.
• Clause 6.1 keeps the last seven speech-frame LP and energy parameters in memory and uses them to form the first SID frame after a speech burst. This gives a smoother transition at the end of speech.
• Clause 6.2 uses the AMR speech decoder algorithm, with fixed-codebook excitation generated from pseudorandom numbers, adaptive codebook gain set to zero, and pitch delay set to 40. In practice, the decoder synthesizes noise that follows the transmitted spectral and energy cues.
• Clause 7 points to a bit-exact computational description in GSM06.73 and gives the bit allocation order for comfort-noise encoding. That is the basis for interoperable implementations and test vectors.

What terms does SIST EN 301 706 V7.1.1:2003 define?

• Frame: a 20 ms time interval used by the AMR speech transcoder and, in this document, the basic unit for comfort-noise averaging.
• SID frame: a Silence Descriptor frame that carries background-noise information or tells the decoder to start generating comfort noise.
• Speech frame: a traffic frame that is not a SID frame.
• Voice Activity Detection (VAD) flag: the flag that marks whether the current frame is treated as speech activity or inactivity.
• TX_TYPE: the transmit-side classification that can be SPEECH, SID_FIRST, SID_UPD, or NO_DATA.
• RX_TYPE: the receive-side classification of the incoming traffic frame, used to decide how comfort noise is updated.

Who uses SIST EN 301 706 V7.1.1:2003?

SIST EN 301 706 V7.1.1:2003 is used by engineers who implement AMR speech coding in GSM MSs and BSSs, especially where DTX and comfort noise are part of the design. It is also relevant to verification teams that need to check SID frame generation, SID reception, and smooth comfort-noise synthesis. Buyers and quality managers use it to confirm that a GSM platform supports the required AMR behaviour on the transmit and receive sides.

What changed in SIST EN 301 706 V7.1.1:2003 from the previous edition?

Annex A records a change from Version 7.1.0 to Version 7.1.1: the averaging formula was corrected. The annex also notes the update to Version 7.1.1 for publication.

Which standards are used with SIST EN 301 706 V7.1.1:2003?

The document cites these GSM references:

• GSM01.04 - provides abbreviations and acronyms.
• GSM06.73 - gives the bit-exact ANSI-C computational description for comfort-noise encoding and generation.
• GSM06.90 - defines AMR speech transcoding and the decoder/encoder operations used by this document.
• GSM06.91 - covers substitution and muting of lost frames for AMR speech traffic channels.
• GSM06.93 - defines DTX operation, frame classification, and the conditions for SID updates and comfort-noise generation.

For this Release 1998 document, GSM references apply as Release 1998 versions.

What does the SIST EN 301 706 V7.1.1:2003 document contain?

The document contains the transmit-side and receive-side procedures for comfort-noise handling, including averaging of LSF and energy parameters, SID frame handling, and noise synthesis steps. It also includes the bit allocation for comfort-noise encoding in Table 1, so implementers know how the SID information is packed. Clause 7 points to the bit-exact implementation in GSM06.73, which is useful for code development and interoperability testing. Annex A provides the document change history.

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Digital cellular telecommunications system (Phase 2+) (GSM); Comfort noise aspects for Adaptive Multi-Rate (AMR) speech traffic channels (GSM 06.92 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 301 706 Version 7.1.1SIST EN 301 706 V7.1.1:2003en01-december-2003SIST EN 301 706 V7.1.1:2003SLOVENSKI
STANDARD
ETSIEN301706V7.1.1(1999-12)EuropeanStandard(Telecommunicationsseries)Digitalcellulartelecommunicationsystem(Phase2+);ComfortnoiseaspectsforAdaptiveMulti-Rate(AMR)speechtrafficchannels(GSM06.92version7.1.1Release1998)GLOBALSYSTEMFORMOBILECOMMUNICATIONSRSIST EN 301 706 V7.1.1:2003

ETSIETSIEN301706V7.1.1(1999-12)2(GSM06.92version7.1.1Release1998)ReferenceDEN/SMG-110692Q7KeywordsDigitalcellulartelecommunicationssystem,GlobalSystemforMobilecommunications(GSM)ETSIPostaladdressF-06921SophiaAntipolisCedex-FRANCEOfficeaddress650RoutedesLucioles-SophiaAntipolisValbonne-FRANCETel.:[phone]Fax:[phone]SiretN°34862356200017-NAF742CAssociationàbutnonlucratifenregistréeàlaSous-PréfecturedeGrasse(06)N°7803/[e-mail]ETSIdeliverablecanbedownloadedfromhttp://www.etsi.orgIfyoufinderrorsinthepresentdocument,sendyourcommentto:[e-mail]Ideliverablemaybemadeavailableinmorethanoneelectronicversionorinprint.Inanycaseofexistingorperceiveddifferenceincontentsbetweensuchversions,thereferenceversionisthePortableDocumentFormat(PDF).Incaseofdispute,thereferenceshallbetheprintingonETSIprintersofthePDFversionkeptonaspecificnetworkdrivewithinETSISecretariat.CopyrightNotificationNopartmaybereproducedexceptasauthorizedbywrittenpermission.Thecopyrightandtheforegoingrestrictionextendtoreproductioninallmedia.©EuropeanTelecommunicationsStandardsInstitute1999.Allrightsreserved.SIST EN 301 706 V7.1.1:2003

ETSIETSIEN301706V7.1.1(1999-12)3(GSM06.92version7.1.1Release1998)ContentIntellectualPropertyRights.4Foreword.41Scope.52References.53Definitions,symbolsandabbreviations.53.1Definitions.53.2Symbols.63.3Abbreviations.64General.75Functionsonthetransmit(TX)side.75.1LSFevaluation.75.2Frameenergycalculation.85.3ModificationofthespeechencodingalgorithmduringSIDframegeneration.85.4SID-frameencoding.96Functionsonthereceive(RX)side.96.1AveraginganddecodingoftheLPandenergyparameters.96.2Comfortnoisegenerationandupdating.107Computationaldetailsandbitallocation.11AnnexA(informative):Documentchangehistory.12History.13SIST EN 301 706 V7.1.1:2003

ETSIETSIEN301706V7.1.1(1999-12)4(GSM06.92version7.1.1Release1998)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)hasbeenproducedbySpecialMobileGroup(SMG).ThepresentdocumentintroducestheAdaptiveMulti-Rate(AMR)speechtrafficchannelswithinthedigitalcellulartelecommunicationssystem.ThecontentsofthepresentdocumentissubjecttocontinuingworkwithinSMGandmaychangefollowingformalSMGapproval.ShouldSMGmodifythecontentsofthepresentdocumentitwillbere-releasedwithanidentifyingchangeofreleasedateandanincreaseinversionnumberasfollows:Version7.x.ywhere:7indicatesRelease1998ofGSMPhase2+xtheseconddigitisincrementedforallchangesofsubstance,i.e.technicalenhancements,corrections,updates,etc.ythethirddigitisincrementedwheneditorialonlychangeshavebeenincorporatedinthespecification.NationaltranspositiondatesDateofadoptionofthisEN:3December1999DateoflatestannouncementofthisEN(doa):31March2000DateoflatestpublicationofnewNationalStandardorendorsementofthisEN(dop/e):30September2000DateofwithdrawalofanyconflictingNationalStandard(dow):30September2000SIST EN 301 706 V7.1.1:2003

ETSIETSIEN301706V7.1.1(1999-12)5(GSM06.92version7.1.1Release1998)1ScopeThepresentdocumentgivesthedetailedrequirementsforthecorrectoperationofthebackgroundacousticnoiseevaluation,noiseparameterencoding/decodingandcomfortnoisegenerationinMobileStations(MSs)andBaseStationSystems(BSSs)duringDiscontinuousTransmission(DTX)onadaptivemulti-ratefullrateandhalfratespeechtrafficchannels.TherequirementsdescribedinthepresentdocumentaremandatoryforimplementationinallGSMMSscapableofsupportingtheadaptivemulti-ratefullrateandhalftatespeechtrafficchannels.ThereceiverrequirementsaremandatoryforimplementationinallGSMBSSscapableofsupportingtheadaptivemulti-ratefullrateandhalfratespeechtrafficchannels,thetransmitterrequirementsonlyforthosewheredownlinkDTXwillbeused.IncaseofdiscrepancybetweentherequirementsdescribedinthepresentdocumentandthefixedpointcomputationaldescriptionoftheserequirementscontainedinGSM06.73[2],thedescriptioninGSM06.73[2]willprevail.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:"Digitalcellulartelecommunicationsystem(Phase2+);Abbreviationsandacronyms".[2]GSM06.73:"Digitalcellulartelecommunicationssystem(Phase2+);ANSI-CcodefortheGSMAdaptiveMulti-Ratespeechcodec".[3]GSM06.90:"Digitalcellulartelecommunicationssystem(Phase2+);AdaptiveMulti-Ratespeechtranscoding".[4]GSM06.91:"Digitalcellulartelecommunicationssystem(Phase2+);SubstitutionandmutingoflostframeforAdaptiveMulti-Ratespeechtrafficchannels".[5]GSM06.93:"Digitalcellulartelecommunicationssystem(Phase2+);Discontinuoustransmission(DTX)forAdaptiveMulti-Ratespeechtrafficchannels".3Definitions,symbolsandabbreviations3.1DefinitionsForthepurposeofthepresentdocument,thefollowingtermsanddefinitionsapply.Frame:timeintervalof20mscorrespondingtothetimesegmentationoftheadaptivemulti-ratespeechtranscoder,alsousedasashorttermfortrafficframe.SIST EN 301 706 V7.1.1:2003

ETSIETSIEN301706V7.1.1(1999-12)6(GSM06.92version7.1.1Release1998)SIDframes:specialSID(SilenceDescriptor)frames.Itmayconveyinformationontheacousticbackgroundnoiseorinformthedecoderthatitshouldstartgeneratingbackgroundnoise.Speechframe:trafficframethatcannotbeclassifiedasaSIDframe.VADflag:voiceActivityDetectionflag.TX_TYPE:oneofSPEECH,SID_FIRST,SID_UPD,NO_DATA(definedinGSM06.93).RX_TYPE:classificationofthereceivedtrafficframe(definedinGSM06.93).OtherdefinitionsoftermsusedinthepresentdocumentcanbefoundinGSM06.90[3]andGSM06.93[5].TheoveralloperationofDTXisdescribedinGSM06.93[5].3.2SymbolsForthepurposeofthepresentdocument,thefollowingsymbolsapply.Boldfacesymbolsareusedforvectorvariables.[]fTfff=1210.UnquantizedLSFvector[].fTfff=1210QuantizedLSFvectorf()mUnquantizedLSFvectorofframemf()mQuantizedLSFvectorofframemfmeanAveragedLSFparametervectorenlogLogarithmicframeenergyenmeanlogAveragedlogarithmicframeenergyfrefReferencevectorforLSFquantizationeComputedLSFparameterpredictionresidualeQuantizedLSFparameterpredictionresidualxnnab()=()()()()=++++−+xaxaxbxb113.3AbbreviationsForthepurposeofthepresentdocument,thefollowingabbreviationsapply.AMRAdaptiveMulti-RateBSSBaseStationSubsystemDTXDiscontinuousTransmissionMSMobileStationSIDSIlenceDescriptorLPLinearPredictionLSPLineSpectralPairLSFLineSpectralFrequencyRXReceiveTXTransmitVADVoiceActivityDetectorForabbreviationsnotgiveninthissubclause,seeGSM01.04[1].SIST EN 301 706 V7.1.1:2003

ETSIETSIEN301706V7.1.1(1999-12
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