SIST ETS 300 723 E1:2003

• Abstract:

  This European Telecommunication Standard [ETS] is an introduction to GSM EFR 06.60, GSM EFR 06.11, GSM EFR 06.62, GSM EFR 06.81 and GSM EFR 06.82 ETSs 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 ETSs where each function is specified in detail.

• 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 ETS 300 723 ed.1 (1997-03) - Digital cellular telecommunications system; Enhanced Full Rate (EFR) speech processing functions; General description (GSM 06.51)

SIST ETS 300 723 E1:2003 is the European Telecommunication Standard that introduces the Enhanced Full Rate (EFR) speech processing functions for the GSM system. It is published by ETSI and gives a general overview of the EFR speech path, with pointers to the companion ETSs where each function is specified in detail. For engineers and buyers, it is a map of the EFR speech-processing set, not the detailed algorithm specification itself.

What does SIST ETS 300 723 E1:2003 specify?

SIST ETS 300 723 E1:2003 specifies the overall organization of GSM Enhanced Full Rate speech processing functions in the EFR channel. The document explains how the main speech functions fit together and identifies the ETSs that define each function in detail.

The scope links this overview to the following companion ETSs:

• GSM 06.60 for speech transcoding
• GSM 06.61 for substitution and muting of lost frames
• GSM 06.62 for comfort noise aspects
• GSM 06.81 for discontinuous transmission (DTX)
• GSM 06.82 for Voice Activity Detector (VAD)

The main body is organized into these clauses:

• Clause 4 - General
• Clause 5 - Enhanced Full Rate speech channel transcoding
• Clause 6 - Enhanced Full Rate speech channel discontinuous transmission (DTX)
• Clause 7 - Enhanced Full Rate speech channel Voice Activity Detection (VAD)
• Clause 8 - Enhanced Full Rate speech channel comfort noise insertion
• Clause 9 - Enhanced Full Rate speech channel lost speech frame substitution and muting
• Clause 10 - Enhanced Full Rate codec homing

What are the key requirements of SIST ETS 300 723 E1:2003?

SIST ETS 300 723 E1:2003 describes the EFR speech-processing chain and how the functions interact. In practice, it tells implementers which module does what, what signals pass between modules, and which detailed specification governs each part.

Speech transcoding and codec structure

Clause 5 explains that the speech encoder takes 13-bit uniform PCM input and that the encoded output is passed to channel coding. It also states that the EFR coding scheme is Algebraic Code Excited Linear Prediction (ACELP). For implementers, this means the codec interface, sampling basis and bit stream relationship are fixed by the linked GSM 06.60 specification.

Discontinuous transmission, VAD and comfort noise

Clauses 6 to 8 describe the DTX chain. The transmit side uses a Voice Activity Detector (VAD), the system evaluates background noise, and the receive side inserts comfort noise using Silence Descriptor (SID) information. In practice, this reduces transmitter activity during pauses, which matters for battery life, RF spectrum use, and avoiding abrupt noise changes at the listener end.

Loss handling in the receiver

Clause 9 covers lost speech frame substitution and muting. The receiver replaces an isolated lost speech frame with a predicted frame, and uses muting for several consecutive lost frames. This matters because frame loss can happen in transmission or by frame stealing, and the document points implementers to the companion ETS for the required receiver behavior.

Bit-exact homing and testability

Clause 10 describes codec homing for the transcoder, VAD, DTX system, and comfort noise parts. These functions are defined in bit exact arithmetic, and special inband signalling frames can drive modules into their home states for testing, type approval, and remote maintenance. In practice, this is the part that supports repeatable verification and controlled reset behavior.

Interworking signals and flags

The overview identifies the main flags used in the speech path, including the Speech flag (SP), Bad Frame Indication (BFI), Silence Descriptor (SID) flag, and Time Alignment Flag (TAF). These flags tell connected functions whether a frame contains speech or SID information, whether a frame was damaged, and where SID timing sits in the SACCH multiframe.

What terms does SIST ETS 300 723 E1:2003 define?

SIST ETS 300 723 E1:2003 points the reader to the companion ETSs for formal term definitions, and it uses several key abbreviations throughout the overview.

• ACELP - Algebraic Code Excited Linear Prediction, the speech coding method used for EFR.
• DTX - Discontinuous Transmission, a mode where transmission is switched off for frames without useful speech.
• VAD - Voice Activity Detector, the function that decides whether a frame contains speech.
• SID - Silence Descriptor, the frame used to carry comfort-noise information.
• SP - Speech flag, indicating whether transmitted information bits are speech or SID information.
• BFI - Bad Frame Indication, a receiver-side indication that a frame is damaged or unusable.
• TAF - Time Alignment Flag, marking the position of the SID frame within the SACCH multiframe.

Who uses SIST ETS 300 723 E1:2003?

SIST ETS 300 723 E1:2003 is used by people working on GSM EFR speech functions in mobile stations and network equipment. It is relevant to designers, implementers, and test engineers who need to understand how the speech-processing blocks fit together before working from the detailed ETSs.

It is also relevant for:

• type approval of mobile terminal equipment
• type approval of infrastructure equipment
• remote control and testing for operation and maintenance
• interoperability work on GSM speech paths and DTX behavior

Which standards are used with SIST ETS 300 723 E1:2003?

The document relies on these companion and referenced standards:

• GSM 01.04 - provides abbreviations and acronyms used in GSM documents
• GSM 03.50 - covers transmission planning aspects of the GSM speech service and the audio parts
• GSM 05.03 - defines channel coding used after speech encoding
• GSM 06.53 - gives ANSI-C code for the EFR speech codec
• GSM 06.54 - provides test vectors for the EFR speech codec
• GSM 06.60 - defines EFR speech transcoding
• GSM 06.61 - defines substitution and muting of lost frames
• GSM 06.62 - defines comfort noise aspects
• GSM 06.81 - defines DTX for EFR speech traffic channels
• GSM 06.82 - defines VAD for EFR speech traffic channels

What does the SIST ETS 300 723 E1:2003 document contain?

SIST ETS 300 723 E1:2003 contains a reference configuration in Figure 1 that shows the speech path from the Mobile Station audio side to the PSTN interface. It identifies where transcoding, DTX, VAD, comfort noise, and lost-frame handling sit in the chain.

The document also explains the roles of the SP, SID, BFI and TAF-related signals in the overall mechanism. It describes how bit exact arithmetic and homing support verification, type approval, and maintenance testing. The history section records that this is the first edition of the ETS.

SLOVENSKI STANDARD
01-december-2003
'LJLWDOQLFHOLþQLWHOHNRPXQLNDFLMVNLVLVWHP±)XQNFLMH]DREGHODYRL]EROMãDQHJD
JRYRUDVSROQRKLWURVWMR()5±6SORãQLRSLV*60
Digital cellular telecommunications system; Enhanced Full Rate (EFR) speech
processing functions; General description (GSM 06.51)
Ta slovenski standard je istoveten z: ETS 300 723 Edition 1
ICS:
33.070.50 Globalni sistem za mobilno Global System for Mobile
telekomunikacijo (GSM) Communication (GSM)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN ETS 300 723
TELECOMMUNICATION March 1997
STANDARD
Source: ETSI TC-SMG Reference: DE/SMG-020651
ICS: 33.020
Key words: EFR, digital cellular telecommunications system, Global System for Mobile communications
(GSM), speech
R
GLOBAL SYSTEM FOR
MOBILE COMMUNICATIONS
Digital cellular telecommunications system;
Enhanced Full Rate (EFR) speech processing functions;
General description
(GSM 06.51)
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
Postal address: F-06921 Sophia Antipolis CEDEX - FRANCE
Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
X.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: [e-mail]
Tel.: [phone] - Fax: [phone]
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 1997. All rights reserved.

Page 2
ETS 300 723 (GSM 06.51 version 5.1.2): March 1997
Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to
"ETSI Editing and Committee Support Dept." at the address shown on the title page.

Page 3
ETS 300 723 (GSM 06.51 version 5.1.2): March 1997
Contents
Foreword .5
1 Scope .7
2 Normative references.7
3 Definitions and abbreviations .7
3.1 Definitions .7
3.2 Abbreviations .8
4 General.8
5 Enhanced Full Rate speech channel transcoding.10
6 Enhanced Full Rate speech channel discontinuous transmission (DTX) .10
7 Enhanced Full Rate speech channel Voice Activity Detection (VAD) .11
8 Enhanced Full Rate speech channel comfort noise insertion .11
9 Enhanced Full Rate speech channel lost speech frame substitution and muting.11
10 Enhanced Full Rate codec homing .12
History.13

Page 4
ETS 300 723 (GSM 06.51 version 5.1.2): March 1997
Blank page
Page 5
ETS 300 723 (GSM 06.51 version 5.1.2): March 1997
Foreword
This European Telecommunication Standard (ETS) has been produced by the Special Mobile Group
(SMG) Technical Committee of the European Telecommunications Standards Institute (ETSI).
This ETS introduces the Enhanced Full Rate (EFR) speech traffic channels within the digital cellular
telecommunications system.
This ETS corresponds to GSM technical specification, GSM 06.51, version 5.1.2
Transposition dates
Date of adoption: 28 February 1997
Date of latest announcement of this ETS (doa): 30 June 1997
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 31 December 1997
Date of withdrawal of any conflicting National Standard (dow): 31 December 1997

Page 6
ETS 300 723 (GSM 06.51 version 5.1.2): March 1997
Blank page
Page 7
ETS 300 723 (GSM 06.51 version 5.1.2): March 1997
1 Scope
This European Telecommunication Standard (ETS) is an introduction to GSM 06.60 (ETS 300 726) [6],
GSM 06.61 (ETS 300 727) [7], GSM 06.62 (ETS 300 728) [8], GSM 06.81 (ETS 300 729) [9] and GSM 06.82
(ETS 300 730) [10] ETSs 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
ETSs where each function is specified in detail.
2 Normative references
This ETS incorporates by dated and undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of any of these publications
apply to this ETS only when incorporated in it by amendment or revision. For undated references, the
latest edition of the publication referred to applies.
[1] GSM 01.04 (ETR 100): "Digital cellular telecommunications system (Phase 2);
Abbreviations and acronyms".
[2] GSM 03.50 (ETS 300 540): "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 (ETS 300 575): "Digital cellular telecommunications system
(Phase 2); Channel coding".
[4] GSM 06.53 (ETS 300 724): "Digital cellular telecommunications system; ANSI-C
code for the GSM Enhanced Full Rate (EFR) speech codec".
[5] GSM 06.54 (ETS 300 725): "Digital cellular telecommunications system; Test
vectors for the GSM Enhanced Full Rate (EFR) speech codec".
[6] GSM 06.60 (ETS 300 726): "Digital cellular telecommunications system;
Enhanced Full Rate (EFR) speech transcoding".
[7] GSM 06.61 (ETS 300 727): "Digital cellular telecommunications system;
Substitution and muting of lost frame for Enhanced Full Rate (EFR) speech
traffic channels".
[8] GSM 06.62 (ETS 300 728): "Digital cellular telecommunications system;
Comfort noise aspects for Enhanced Full Rate (EFR) speech traffic channels".
[9] GSM 06.81 (ETS 300 729): "Digital cellular telecommunications system;
Discontinuous transmission (DTX) for Enhanced Full Rate (EFR) speech traffic
channels".
[10] GSM 06.82 (ETS 300 730): "Digital cellular telecommunications system; Voice
Activity Detector (VAD) for Enhanced Full Rate (EFR) speech traffic channels".
3 Definitions and abbreviations
3.1 Definitions
Definition of terms used in this ETS can be found in GSM 06.60 (ETS 300 726) [6], GSM 06.61
(ETS 300 727) [7], GSM 06.62 (ETS 300 728) [8], GSM 06.81 (ETS 300 729) [9] and GSM 06.82
(ETS 300 730) [10].
Page 8
ETS 300 723 (GSM 06.51 version 5.1.2): March 1997
3.2 Abbreviations
For the purposes of this ETS, 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 subclause, see GSM 01.04 (ETR 100) [1].
4 General
Figure 1 presents a reference configuration where the various speech processing functions are identified.
In this figure, the relevant ETSs 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
(ETS 300 540) [2]. These aspects are only considered to the extent that the performance of the audio
parts affect the performance of the speech transcoder.

---------------------- Pag
...