SIST EN 300 723 V8.1.1:2003

• Abstract:

  CRs from SMG#32

• 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 300 723 V8.1.1 (2000-11) - Digital cellular telecommunications system (Phase 2+) (GSM); Enhanced Full Rate (EFR) speech processing functions; General description (GSM 06.51 version 8.1.1 Release 1999)

SIST EN 300 723 V8.1.1:2003 is the Slovenian adoption of ETSI EN 300 723 V8.1.1. It covers Enhanced Full Rate (EFR) speech processing functions for the digital cellular telecommunications system (Phase 2+) (GSM), and it points readers to the detailed GSM standards that define each speech-processing function.

This standard is for people who need to understand how GSM EFR speech is encoded, protected, detected, muted, and tested. In practice, it helps equipment makers, test labs, network engineers, and type-approval teams work from the same speech-processing framework.

What does SIST EN 300 723 V8.1.1:2003 specify?

SIST EN 300 723 V8.1.1:2003 gives a general description of the GSM EFR speech processing chain and identifies the standards that specify each function in detail. Clause 1 makes clear that it is an introduction to the ENs covering the speech processing functions in the Enhanced Full Rate channel of the GSM system.

The document is organized into clauses for the scope, references, definitions and abbreviations, a general overview, and then the main speech-processing functions. It ends with an informative annex that records change request history.

Annex	What it covers
Annex A	Change Request History

What are the key requirements of SIST EN 300 723 V8.1.1:2003?

SIST EN 300 723 V8.1.1:2003 does not define the detailed algorithms itself for most functions. Instead, it states which companion standards define transcoding, DTX, VAD, comfort noise, lost-frame handling, and codec homing, and it explains how those functions fit together.

Speech transcoding

Clause 5 describes the EFR speech channel transcoding path. The speech encoder takes 13-bit uniform PCM input, and the coded speech is passed to GSM 05.03 channel coding; the receive path performs the reverse operation. For readers, this means the document defines the speech coding chain and the interfaces between the codec and the radio channel.

DTX and VAD

Clause 6 explains discontinuous transmission (DTX), where the transmitter is active only for frames that carry useful information. It identifies the Voice Activity Detector (VAD), background-noise evaluation, comfort-noise generation, and the use of SIlence Descriptor (SID) frames, SP flags, and interaction with the Radio SubSystem (RSS). In practice, this is what reduces air-interface activity during pauses and helps battery life and spectrum use.

Clause 7 states that the Enhanced Full Rate VAD uses parameters from the speech encoder to decide whether a 20 ms frame contains speech. The VAD flag feeds the TX DTX handler, but it does not directly key the transmitter. That distinction matters because the DTX control chain is split between speech analysis and radio control.

Comfort noise and lost frames

Clause 8 covers comfort noise insertion at the receiver. It describes background-noise measurement, SID encoding and decoding, and comfort-noise generation so that pauses do not sound like sudden drops in background sound.

Clause 9 covers lost speech frame substitution and muting. Isolated lost speech frames are replaced by predicted content, while several consecutive lost frames trigger muting. This is the receiver-side behavior that limits the audible effect of transmission errors or frame stealing.

Homing and testing

Clause 10 describes codec homing for bit-exact parts of the EFR speech transcoder, VAD, DTX system, and comfort-noise functions. It ties this to home-state behavior, test sequences, and use in mobile terminal type approval, infrastructure type approval, and remote operation and maintenance. For implementers, this is the part that supports repeatable verification.

Alternative implementation

Clause 11 allows an alternative EFR implementation based on the Adaptive Multi Rate 12.2 kbit/s mode from TS 26.071, with GSM 06.81 DTX transmission format and GSM 06.62 comfort-noise generation still used. It also notes that compliance is verified with the digital test sequences in GSM 06.54. This gives implementers a second route to interoperability while keeping the GSM EFR behavior.

What terms does SIST EN 300 723 V8.1.1:2003 define?

• ACELP - Algebraic Code Excited Linear Prediction, the speech coding method used for the EFR codec.
• DTX - Discontinuous Transmission, a mode that sends only frames with useful speech information.
• VAD - Voice Activity Detector, the function that decides whether a frame contains speech.
• SID - Silence Descriptor, the frame that carries noise information during pauses.
• SP - Speech flag, used to indicate whether transmitted information is speech or SID information.
• BFI - Bad Frame Indication, a signal that marks a received frame as bad.
• TAF - Time Alignment Flag, which marks the position of a SID frame in the SACCH multiframe.

Who uses SIST EN 300 723 V8.1.1:2003?

SIST EN 300 723 V8.1.1:2003 is used by GSM equipment designers, codec implementers, test laboratories, and type-approval teams. It is also relevant to infrastructure equipment makers, mobile terminal makers, and people involved in operation and maintenance of GSM systems.

In practice, these users need it to understand how EFR speech functions connect to the rest of the GSM chain, how to verify bit-exact behavior, and how to apply the named companion standards for detailed implementation and testing.

What changed in SIST EN 300 723 V8.1.1:2003 from the previous edition?

Annex A records the change request history leading to Version 8.1.1. It shows earlier release versions and states that the Release 1999 update added mu-law (PCS 1900) to Figure 1 and clause 5, and added the alternative EFR implementation using the AMR 12.2 mode in clauses 4 and 11.

Which standards are used with SIST EN 300 723 V8.1.1:2003?

Clause 2 names the following standards as references that support the document:

• GSM 01.04 - abbreviations and acronyms.
• GSM 03.50 - transmission planning aspects of the speech service, including the audio path.
• GSM 05.03 - channel coding.
• GSM 06.53 - ANSI-C code for the GSM EFR speech codec.
• GSM 06.54 - test vectors for the GSM EFR speech codec.
• GSM 06.60 - Enhanced Full Rate speech transcoding.
• GSM 06.61 - substitution and muting of lost frame for EFR speech traffic channels.
• GSM 06.62 - comfort noise aspects for EFR speech traffic channels.
• GSM 06.81 - discontinuous transmission for EFR speech traffic channels.
• GSM 06.82 - Voice Activity Detector for EFR speech traffic channels.
• TS 26.071 - the 12.2 kbit/s AMR speech coder mode used for the alternative implementation in clause 11.

What does the SIST EN 300 723 V8.1.1:2003 document contain?

SIST EN 300 723 V8.1.1:2003 contains a reference configuration figure that shows the speech path between the Mobile Station (MS), the Public Switched Telephone Network (PSTN), and the Radio SubSystem (RSS). It also identifies the signal types used in that path, including PCM, VAD flag, encoded speech frames, SID frames, SP flag, BFI, and TAF.

The document includes the general descriptions of transcoding, DTX, VAD, comfort noise, lost-frame handling, and homing behavior, plus the clause on the alternative AMR-based implementation. Annex A provides the change-request record used to track revisions and publication updates.

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Digital cellular telecommunications system (Phase 2+) (GSM); Enhanced Full Rate (EFR) speech processing functions; General description (GSM 06.51 version 8.1.1 Release 1999)33.070.50Globalni sistem za mobilno telekomunikacijo (GSM)Global System for Mobile Communication (GSM)ICS:Ta slovenski standard je istoveten z:EN 300 723 Version 8.1.1SIST EN 300 723 V8.1.1:2003en01-december-2003SIST EN 300 723 V8.1.1:2003SLOVENSKI
STANDARD
FOR MOBILE COMMUNICATIONSR
ETSI ETSI EN 300 723 V8.1.1 (2000-11)2(GSM 06.51 version 8.1.1 Release 1999)
Reference REN/SMG-110651Q8R1 Keywords Digital cellular telecommunications system, Global System for Mobile communications (GSM) ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE
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Important notice Individual copies of the present document can be downloaded from: http://www.etsi.org The present document may be made available in more than one electronic version or in print. In any case of existing or perceived difference in contents between such versions, the reference version is the Portable Document Format (PDF). In case of dispute, the reference shall be the printing on ETSI printers of the PDF version kept on a specific network drive within ETSI Secretariat. Users of the present document should be aware that the document may be subject to revision or change of status. Information on the current status of this and other ETSI documents is available at http://www.etsi.org/tb/status/ If you find errors in the present document, send your comment to: [e-mail] Copyright Notification No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 2000. All rights reserved.
ETSI ETSI EN 300 723 V8.1.1 (2000-11)3(GSM 06.51 version 8.1.1 Release 1999) Contents Intellectual Property Rights.4 Foreword.4 1 Scope.5 2 References.5 3 Definitions and abbreviations.6 3.1 Definitions.6 3.2 Abbreviations.6 4 General.6 5 Enhanced Full Rate speech channel transcoding.8 6 Enhanced Full Rate speech channel discontinuous transmission (DTX).8 7 Enhanced Full Rate speech channel Voice Activity Detection (VAD).9 8 Enhanced Full Rate speech channel comfort noise insertion.9 9 Enhanced Full Rate speech channel lost speech frame substitution and muting.9 10 Enhanced Full Rate codec homing.10 11 Alternative Enhanced Full Rate implementation using the Adaptive Multi Rate 12.2 kbit/s mode.10 Annex A (informative): Change Request History.11 History.12
ETSI ETSI EN 300 723 V8.1.1 (2000-11)4(GSM 06.51 version 8.1.1 Release 1999) Intellectual Property Rights IPRs essential or potentially essential to the present document may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (http://www.etsi.org/ipr). Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become, essential to the present document. Foreword This European Standard (Telecommunications series) has been produced by ETSI Technical Committee Special Mobile Group (SMG). The present document introduces the Enhanced Full Rate (EFR) speech traffic channels within the digital cellular telecommunications system. The contents of the present document is subject to continuing work within SMG and may change following formal SMG approval. Should SMG modify the contents of the present document it will be re-released with an identifying change of release date and an increase in version number as follows: Version 8.x.y where: 8 indicates Release 1999 of GSM Phase 2+. x the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections, updates, etc. y the third digit is incremented when editorial only changes have been incorporated in the specification.
National transposition dates Date of adoption of this EN: 24 November 2000 Date of latest announcement of this EN (doa): 28 February 2001 Date of latest publication of new National Standard or endorsement of this EN (dop/e):
31 August 2001 Date of withdrawal of any conflicting National Standard (dow): 31 August 2001
ETSI ETSI EN 300 723 V8.1.1 (2000-11)5(GSM 06.51 version 8.1.1 Release 1999) 1 Scope The present document is an introduction to GSM 06.60 [6], GSM 06.61 [7], GSM 06.62 [8], GSM 06.81 [9] and GSM 06.82 [10] ENs dealing with the speech processing functions in the Enhanced Full Rate channel of the GSM system. A general overview of the speech processing functions is given, with reference to the ENs where each function is specified in detail. 2 References The following documents contain provisions which, through reference in this text, constitute provisions of the present document. • References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. • For a specific reference, subsequent revisions do not apply. • For a non-specific reference, the latest version applies. • A non-specific reference to an ETS shall also be taken to refer to later versions published as an EN with the same number. • For this Release 1999 document, references to GSM documents are for Release 1999 versions (version 8.x.y). [1] GSM 01.04: "Digital cellular telecommunications system (Phase 2+); Abbreviations and acronyms". [2] GSM 03.50: "Digital cellular telecommunications system (Phase 2+); Transmission planning aspects of the speech service in the GSM Public Land Mobile Network (PLMN) system". [3] GSM 05.03: "Digital cellular telecommunications system (Phase 2+); Channel coding". [4] GSM 06.53: "Digital cellular telecommunications system (Phase 2+); ANSI-C code for the GSM Enhanced Full Rate (EFR) speech codec".
[5] GSM 06.54: "Digital cellular telecommunications system (Phase 2+); Test vectors for the GSM Enhanced Full Rate (EFR) speech codec". [6] GSM 06.60: "Digital cellular telecommunications system (Phase 2+); Enhanced Full Rate (EFR) speech transcoding". [7] GSM 06.61: "Digital cellular telecommunications system (Phase 2+); Substitution and muting of lost frame for Enhanced Full Rate (EFR) speech traffic channels". [8] GSM 06.62: "Digital cellular telecommunications system (Phase 2+); Comfort noise aspects for Enhanced Full Rate (EFR) speech traffic channels". [9] GSM 06.81: "Digital cellular telecommunications system (Phase 2+); Discontinuous transmission (DTX) for Enhanced Full Rate (EFR) speech traffic channels". [10] GSM 06.82: "Digital cellular telecommunications system (Phase 2+); Voice Activity Detector (VAD) for Enhanced Full Rate (EFR) speech traffic channels". SIST EN 300 723 V8.1.1:2003

ETSI ETSI EN 300 723 V8.1.1 (2000-11)6(GSM 06.51 version 8.1.1 Release 1999) 3 Definitions and abbreviations 3.1 Definitions Definition of terms used in the present document can be found in GSM 06.60 [6], GSM 06.61 [7], GSM 06.62 [8], GSM 06.81 [9] and GSM 06.82 [10]. 3.2 Abbreviations For the purposes of the present document, the following abbreviations apply: ACELP Algebraic Code Excited Linear Prediction BFI Bad Frame Indication
BSS Base Station System CCITT Comité Consultatif International Télégraphique et Téléphonique DTX Discontinuous Transmission ETS European Telecommunication Standard GSM Global System for Mobile communications MS Mobile Station PCM Pulse Code Modulated PLMN Public Land Mobile Network
PSTN Public Switched Telephone Network RF Radio Frequency RSS Radio SubSystem RX Receive SACCH Slow Associated Control CHannel SID SIlence Descriptor SP flag SPeech flag TAF Time Alignment Flag TX Transmit For abbreviations not given in this clause, see GSM 01.04 [1]. 4 General Figure 1 presents a reference configuration where the various speech processing functions are identified. In this figure, the relevant Standards for each function are also indicated. In figure 1, the audio parts including analogue to digital and digital to analogue conversion are included, to show the complete speech path between the audio input/output in the Mobile Station (MS) and the digital interface of the PSTN. The detailed specification of the audio parts are contained in GSM 03.50 [2]. These aspects are only considered to th
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