SIST EN 300 970 V7.0.1:2003
(Main)Digital cellular telecommunications system (Phase 2+) (GSM); Half rate speech; Substitution and muting of lost frames for half rate speech traffic channels (GSM 06.21 version 7.0.1 Release 1998)
- Abstract
Upgrade from Phase 2+ to Release 1998
- 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
- Mandate
- T-172
SIST EN 300 970 V7.0.1:2003 is the Slovenian adoption of ETSI EN 300 970 Version 7.0.1 for GSM half rate speech. It specifies the receive-side substitution and muting procedure for lost or unreliable speech and Silence Descriptor (SID) frames on half rate speech traffic channels, for GSM Base Station Systems (BSS) and Mobile Stations (MS).
What does SIST EN 300 970 V7.0.1:2003 specify?
SIST EN 300 970 V7.0.1:2003 defines how the Receive (RX) Discontinuous Transmission (DTX) handler shall react when frames from the Radio SubSystem (RSS) are lost or decoded unreliably. The aim is to conceal missing speech and avoid harsh audio effects when the channel degrades.
The document is organized into Scope, References, Definitions and abbreviations, General, Requirements, Example solutions, and an informative Annex A.
| Annex | What it covers |
|---|---|
| Annex A | Change Request History |
What are the key requirements of SIST EN 300 970 V7.0.1:2003?
SIST EN 300 970 V7.0.1:2003 centers on two indicators from the RSS: Bad Frame Indication (BFI) for lost frames and Unreliable Frame Indication (UFI) for suspect frames. The practical goal is to keep speech output intelligible and to make frame loss less noticeable to the user.
Detecting unreliable frames
Clause 4 says a set BFI flag means the frame is lost, while a set UFI flag means the frame was decoded but may be wrong. Clause 5.1 then requires extra error detection based on both frame-parameter behavior and output-signal behavior.
In practice, the decoder does not rely only on the channel flag. It checks whether the received frame looks usable, and if not, it sets BFI and switches to substitution and muting.
Concealing unreliable speech or SID frames
Clause 5.1.2 requires output-signal concealment when a frame is still considered usable but looks suspicious. The decoder compares the current output signal with the previous valid frames and limits large jumps.
For implementers, this means the decoder should smooth abrupt changes before they become audible. That reduces artifacts even when the frame was not formally marked as lost.
Replacing lost speech frames
Clause 5.2.1 says the first and second lost speech frames shall be partly or completely substituted with the last valid speech frame, and the output shall not be muted directly. This keeps short interruptions from turning into silence too quickly.
Clause 5.2.2 then requires gradual muting for later lost speech frames, with the output level falling to silence after a maximum of 80 ms. The muting is then maintained if losses continue.
Replacing lost SID frames
Clause 5.2.3 says the first and second lost SID frames shall be substituted with the last good SID frame, again without direct muting. That preserves background-noise characteristics during brief frame losses.
Clause 5.2.4 requires gradual muting for subsequent lost SID frames, with silence reached after a maximum of 320 ms. In practice, the decoder keeps the comfort-noise behavior for longer than speech before fading out.
What the example solutions show
Clause 6 gives example solutions in C code, referenced to GSM06.06. These examples show one way to implement error detection, output-signal concealment, and substitution/muting.
The examples use signal-energy checks, LPC synthesis behavior, and an 8-state machine for lost speech frames. For lost SID frames, the example repeats the last good SID frame and reduces frame energy step by step.
What terms does SIST EN 300 970 V7.0.1:2003 define?
- Bad Frame Indication (BFI) - A flag showing that a speech or SID frame is lost, which triggers substitution and muting.
- Unreliable Frame Indication (UFI) - A flag showing that a frame may be erroneous even though it was received.
- Discontinuous Transmission (DTX) - The receive-side handling used to conceal lost frames and manage muting in half rate speech traffic channels.
- Silence Descriptor (SID) - A frame that carries background-noise information and is handled separately from speech frames.
- Receive (RX) - The speech-processing path on the receive side where this procedure is applied.
- Radio SubSystem (RSS) - The source of the received speech or SID frames and the BFI/UFI indications.
- Base Station System (BSS) - The GSM infrastructure side that implements this procedure.
- Mobile Station (MS) - The user equipment that implements this procedure when it supports half rate speech traffic channels.
Who uses SIST EN 300 970 V7.0.1:2003?
SIST EN 300 970 V7.0.1:2003 is used by GSM speech codec engineers, base-station and handset developers, and integration teams working on half rate speech traffic channels. It is also relevant to test and quality teams checking how equipment behaves when frames are lost, unreliable, or repeatedly missing.
The document matters in practice when implementing the RX DTX handler, validating decoder behavior, and checking that BSS and MS products treat speech and SID frame loss in a consistent way.
What changed in SIST EN 300 970 V7.0.1:2003 from the previous edition?
SIST EN 300 970 V7.0.1:2003 is identified as version 7.0.1 for Release 1998. Annex A records the change request history across the ETSI publication, Release 1996, Release 1997, and Release 1998 versions, ending with the publication update to V7.0.1.
Which standards are used with SIST EN 300 970 V7.0.1:2003?
| Standard | What it contributes |
|---|---|
| GSM01.04 | Abbreviations and acronyms used in the GSM series |
| GSM05.03 | Channel coding terms and definitions used by this document |
| GSM06.20 | Half rate speech transcoding, including shared definitions |
| GSM06.41 | Discontinuous Transmission (DTX) for half rate speech traffic channels |
| GSM06.06 | ANSI-C code for the GSM half rate speech codec, used for the example solutions |
The foreword also places this document in the half rate speech series together with GSM06.02, GSM06.22, GSM06.42 and GSM06.07.
What does the SIST EN 300 970 V7.0.1:2003 document contain?
SIST EN 300 970 V7.0.1:2003 contains the procedure rules, the mandatory frame-handling requirements, and example implementations. Clause 6 gives practical C-code examples for unreliable-frame detection, output concealment, lost speech frame handling, and lost SID frame handling.
The examples refer to signal energy, LPC synthesis, code vectors, and a state machine, so implementers can translate the text requirements into decoder logic. Annex A provides the change request history for traceability.
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Frequently Asked Questions
SIST EN 300 970 V7.0.1:2003 is a standard published by the Slovenian Institute for Standardization (SIST). Its full title is "Digital cellular telecommunications system (Phase 2+) (GSM); Half rate speech; Substitution and muting of lost frames for half rate speech traffic channels (GSM 06.21 version 7.0.1 Release 1998)". This standard covers: Upgrade from Phase 2+ to Release 1998
Upgrade from Phase 2+ to Release 1998
SIST EN 300 970 V7.0.1:2003 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 300 970 V7.0.1:2003 is associated with the following European legislation: Standardization Mandates: T-172. When a standard is cited in the Official Journal of the European Union, products manufactured in conformity with it benefit from a presumption of conformity with the essential requirements of the corresponding EU directive or regulation.
SIST EN 300 970 V7.0.1:2003 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+) (GSM); Half rate speech; Substitution and muting of lost frames for half rate speech traffic channels (GSM 06.21 version 7.0.1 Release 1998)33.070.50Globalni sistem za mobilno telekomunikacijo (GSM)Global System for Mobile Communication (GSM)ICS:Ta slovenski standard je istoveten z:EN 300 970 Version 7.0.1SIST EN 300 970 V7.0.1:2003en01-december-2003SIST EN 300 970 V7.0.1:2003SLOVENSKI
STANDARD
ETSIEN300970V7.0.1(2000-01)EuropeanStandard(Telecommunicationsseries)Digitalcellulartelecommunicationssystem(Phase2+);Halfratespeech;Substitutionandmutingoflostframesforhalfratespeechtrafficchannels(GSM06.21version7.0.1Release1998)GLOBALSYSTEMFORMOBILECOMMUNICATIONSRSIST EN 300 970 V7.0.1:2003
ETSIETSIEN300970V7.0.1(2000-01)2(GSM06.21version7.0.1Release1998)ReferenceREN/SMG-110621Q7KeywordsDigitalcellulartelecommunicationssystem,GlobalSystemforMobilecommunications(GSM)ETSIPostaladdressF-06921SophiaAntipolisCedex-FRANCEOfficeaddress650RoutedesLucioles-SophiaAntipolisValbonne-FRANCETel.:+33492944200Fax:+33493654716SiretN°34862356200017-NAF742CAssociationàbutnonlucratifenregistréeàlaSous-PréfecturedeGrasse(06)N°7803/88Internetsecretariat@etsi.frIndividualcopiesofthisETSIdeliverablecanbedownloadedfromhttp://www.etsi.orgIfyoufinderrorsinthepresentdocument,sendyourcommentto:editor@etsi.frImportantnoticeThisETSIdeliverablemaybemadeavailableinmorethanoneelectronicversionorinprint.Inanycaseofexistingorperceiveddifferenceincontentsbetweensuchversions,thereferenceversionisthePortableDocumentFormat(PDF).Incaseofdispute,thereferenceshallbetheprintingonETSIprintersofthePDFversionkeptonaspecificnetworkdrivewithinETSISecretariat.CopyrightNotificationNopartmaybereproducedexceptasauthorizedbywrittenpermission.Thecopyrightandtheforegoingrestrictionextendtoreproductioninallmedia.©EuropeanTelecommunicationsStandardsInstitute2000.Allrightsreserved.SIST EN 300 970 V7.0.1:2003
ETSIETSIEN300970V7.0.1(2000-01)3(GSM06.21version7.0.1Release1998)ContentsIntellectualPropertyRights.4Foreword.41Scope.62References.63Definitionsandabbreviations.63.1Definitions.63.2Abbreviations.64General.75Requirements.75.1ErrordetectionandconcealmentincaseofunreliablespeechorSIDframes.75.1.1Errordetection.75.1.2Outputsignalconcealment.75.2FramesubstitutionandmutingincaseoflostspeechorSIDframes.75.2.1Firstandsecondlostspeechframe.75.2.2Subsequentlostspeechframes.85.2.3FirstandsecondlostSIDframe.85.2.4SubsequentlostSIDframes.86Examplesolutions.86.1Examplesolutionforerrordetectionincaseofunreliableframes.86.2Examplesolutionforoutputsignalconcealmentincaseofunreliableframes.86.3Examplesolutionforsubstitutionandmutingoflostspeechframes.86.4ExamplesolutionforsubstitutionandmutingoflostSIDframes.9AnnexA(informative):ChangeRequestHistory.10History.11SIST EN 300 970 V7.0.1:2003
ETSIETSIEN300970V7.0.1(2000-01)4(GSM06.21version7.0.1Release1998)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)hasbeenproducedbytheSpecialMobileGroup(SMG).ThepresentdocumentdefinesaframesubstitutionandmutingprocedurewhichshallbeusedbytheReceive(RX)DiscontinuousTransmission(DTX)handlerforthehalfratespeechtrafficchannelswithinthedigitalcellulartelecommunicationssystem.Thepresentdocumentispartofaseriescoveringthehalfratespeechtrafficchannelsasdescribedbelow:GSM06.02"Digitalcellulartelecommunicationssystem(Phase2+);Halfratespeech;Halfratespeechprocessingfunctions".GSM06.20"Digitalcellulartelecommunicationssystem(Phase2+);Halfratespeech;Halfratespeechtranscoding".GSM06.21"Digitalcellulartelecommunicationssystem(Phase2+);Halfratespeech;Substitutionandmutingoflostframesforhalfratespeechtrafficchannels".GSM06.22"Digitalcellulartelecommunicationssystem(Phase2+);Halfratespeech;Comfortnoiseaspectsforhalfratespeechtrafficchannels".GSM06.41"Digitalcellulartelecommunicationssystem(Phase2+);Halfratespeech;DiscontinuousTransmission(DTX)forhalfratespeechtrafficchannels".GSM06.42"Digitalcellulartelecommunicationssystem(Phase2+);Halfratespeech;VoiceActivityDetector(VAD)forhalfratespeechtrafficchannels".GSM06.06"Digitalcellulartelecommunicationssystem(Phase2+);Halfratespeech;ANSI-CcodefortheGSMhalfratespeechcodec".GSM06.07"Digitalcellulartelecommunicationssystem(Phase2+);Halfratespeech;TestsequencesfortheGSMhalfratespeechcodec".ThecontentsofthepresentdocumentissubjecttocontinuingworkwithinSMGandmaychangefollowingformalSMGapproval.ShouldSMGmodifythecontentsofthepresentdocumentitwillbere-releasedwithanidentifyingchangeofreleasedateandanincreaseinversionnumberasfollows:Version7.x.ywhere:7indicatesRelease1998ofGSMPhase2+.xtheseconddigitisincrementedforallchangesofsubstance,i.e.technicalenhancements,corrections,updates,etc.ythethirddigitisincrementedwheneditorialonlychangeshavebeenincorporatedinthespecification.SIST EN 300 970 V7.0.1:2003
ETSIETSIEN300970V7.0.1(2000-01)5(GSM06.21version7.0.1Release1998)NationaltranspositiondatesDateofadoptionofthisEN:31December1999DateoflatestannouncementofthisEN(doa):31March2000DateoflatestpublicationofnewNationalStandardorendorsementofthisEN(dop/e):30September2000DateofwithdrawalofanyconflictingNationalStandard(dow):30September2000SIST EN 300 970 V7.0.1:2003
ETSIETSIEN300970V7.0.1(2000-01)6(GSM06.21version7.0.1Release1998)1ScopeThepresentdocumentdefinesaframesubstitutionandmutingprocedurewhichshallbeusedbytheReceive(RX)DiscontinuousTransmission(DTX)handlerwhenoneormorelostorunreliablespeechorSIlenceDescriptor(SID)framesarereceivedfromtheRadioSubSystem(RSS).TherequirementsofthepresentdocumentaremandatoryforimplementationinallGSMBaseStationSystems(BSS)sandMobileStations(MS)scapableofsupportingthehalfratespeechtrafficchannel.2ReferencesThe
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