SIST ETS 300 972 E2:2003

Digital cellular telecommunications system (Phase 2+) (GSM); Half rate speech; Discontinuous Transmission (DTX) for half rate speech traffic channels (GSM 06.41 version 5.1.1)

This European Telecommunication Standard (ETS) gives a description of the general baseband operation of half rate speech traffic channels in the transmitter and in the receiver of GSM Mobile Stations (MS)s and Base Station Systems (BSS)s during Discontinuous Transmission (DTX). For clarity, the description is structured according to the block diag rams in figures 1 and 4. Except in the case described below, this stru cture of distributing the various functions between system entities is not mandatory for implementation, as long as the operation on the air interface and on the speech decoder output remains the same. In the case of BSSs where the speech transcoder is located remotely in the Base Station Controller (BSC), the implementation of the interfac es between the DTX Handlers and the Radio Sub System (RSS) as describe d in this ETS together with all their flags is mandatory, being a part of the A-bis interface as described in GSM 08.61 (ETS 300 979) [10]. The DTX functions described in this ETS are mandatory for implementati on in all GSM MSs. The receiver requirements are mandatory for impleme ntation in all GSM BSSs, the transmitter requirements only for those w here downlink DTX will be used.

Digitalni celični telekomunikacijski sistem (faza 2+) – Govor s pol hitrosti – Prekinjano oddajanje (DTX) pri kanalih za prenos govora s pol hitrosti (GSM 06.41, različica 5.1.1)

General Information

• 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 300 972 ed.2 (1998-03) - Digital cellular telecommunications system (Phase 2+) (GSM); Half rate speech; Discontinuous Transmission (DTX) for half rate speech traffic channels (GSM 06.41 version 5.1.1)

Standards Content (Sample)

SLOVENSKI STANDARD
SIST ETS 300 972 E2:2003
01-december-2003
'LJLWDOQLFHOLþQLWHOHNRPXQLNDFLMVNLVLVWHPID]D±*RYRUVSROKLWURVWL±
3UHNLQMDQRRGGDMDQMH'7;SULNDQDOLK]DSUHQRVJRYRUDVSROKLWURVWL*60
UD]OLþLFD
Digital cellular telecommunications system (Phase 2+) (GSM); Half rate speech;
Discontinuous Transmission (DTX) for half rate speech traffic channels (GSM 06.41
version 5.1.1)
Ta slovenski standard je istoveten z: ETS 300 972 Edition 2
ICS:
33.070.50 Globalni sistem za mobilno Global System for Mobile
telekomunikacijo (GSM) Communication (GSM)
SIST ETS 300 972 E2:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ETS 300 972 E2:2003

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SIST ETS 300 972 E2:2003
EUROPEAN ETS 300 972
TELECOMMUNICATION March 1998
STANDARD Second Edition
Source: SMG Reference: RE/SMG-110641QR1
ICS: 33.020
Key words: Digital cellular telecommunications system, Global System for Mobile communications (GSM)
R
GLOBAL SYSTEM FOR
MOBILE COMMUNICATIONS
Digital cellular telecommunications system (Phase 2+);
Half rate speech;
Discontinuous Transmission (DTX) for half rate
speech traffic channels
(GSM 06.41 version 5.1.1)
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
Internet: [e-mail] - http://www.etsi.fr - http://www.etsi.org
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 1998. All rights reserved.

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ETS 300 972 (GSM 06.41 version 5.1.1): March 1998
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.

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ETS 300 972 (GSM 06.41 version 5.1.1): March 1998
Contents
Foreword .5
1 Scope .7
2 Normative references.7
3 Definitions, symbols and abbreviations.8
3.1 Definitions .8
3.2 Symbols .9
3.3 Abbreviations .9
4 General.9
4.1 General Organisation.9
5 Transmit (TX) side.10
5.1 General Operation .10
5.1.1 Functions of the TX DTX handler.10
5.1.2 Functions of the TX radio subsystem.11
6 Receive (RX) side .13
6.1 General operation .13
6.1.1 Functions of the RX radio subsystem .13
6.1.2 Functions of the RX DTX handler .14
History.15

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ETS 300 972 (GSM 06.41 version 5.1.1): March 1998
Foreword
This second edition European Telecommunication Standard (ETS) has been produced by the Special
Mobile Group (SMG) of the European Telecommunications Standards Institute (ETSI).
This ETS is a GSM technical specification version 5 and is part of the 1996 release of the GSM Technical
Specifications. This ETS is part of ETSs series covering the half rate speech traffic channels as described
below:
GSM 06.02 ETS 300 966: "Digital cellular telecommunications system (Phase 2+); Half rate
speech; Half rate speech processing functions".
GSM 06.06 ETS 300 967: "Digital cellular telecommunications system (Phase 2+); Half rate
speech; ANSI-C code for the GSM half rate speech codec".
GSM 06.07 ETS 300 968: "Digital cellular telecommunications system (Phase 2+); Half rate
speech; Test sequences for the GSM half rate speech codec".
GSM 06.20 ETS 300 969: "Digital cellular telecommunications system (Phase 2+); Half rate
speech; Half rate speech transcoding".
GSM 06.21 ETS 300 970: "Digital cellular telecommunications system (Phase 2+); Half rate
speech; Substitution and muting of lost frames for half rate speech traffic
channels".
GSM 06.22 ETS 300 971: "Digital cellular telecommunications system (Phase 2+); Half rate
speech; Comfort noise aspects for half rate speech traffic channels".
GSM 06.41 ETS 300 972: "Digital cellular telecommunications system (Phase 2+); Half
rate speech; Discontinuous Transmission (DTX) for half rate speech traffic
channels".
GSM 06.42 ETS 300 973: "Digital cellular telecommunications system (Phase 2+); Half rate
speech; Voice Activity Detector (VAD) for half rate speech traffic channels".
Transposition dates
Date of adoption of this ETS: 3 April 1998
Date of latest announcement of this ETS (doa): 30 June 1998
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 31 December 1998
Date of withdrawal of any conflicting National Standard (dow): 31 December 1998

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ETS 300 972 (GSM 06.41 version 5.1.1): March 1998
1 Scope
This European Telecommunication Standard (ETS) gives a description of the general baseband operation
of half rate speech traffic channels in the transmitter and in the receiver of GSM Mobile Stations (MS)s
and Base Station Systems (BSS)s during Discontinuous Transmission (DTX).
For clarity, the description is structured according to the block diagrams in figures 1 and 4. Except in the
case described below, this structure of distributing the various functions between system entities is not
mandatory for implementation, as long as the operation on the air interface and on the speech decoder
output remains the same.
In the case of BSSs where the speech transcoder is located remotely in the Base Station Controller
(BSC), the implementation of the interfaces between the DTX Handlers and the Radio Sub System (RSS)
as described in this ETS together with all their flags is mandatory, being a part of the A-bis interface as
described in GSM 08.61 (ETS 300 979) [10].
The DTX functions described in this ETS are mandatory for implementation in all GSM MSs. The receiver
requirements are mandatory for implementation in all GSM BSSs, the transmitter requirements only for
those where downlink DTX will be used.
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 350): "Digital cellular telecommunication system (Phase 2+);
Abbreviations and acronyms".
[2] GSM 04.08 (ETS 300 940): "Digital cellular telecommunication system
(Phase 2+); Mobile radio interface layer 3 specification".
[3] GSM 05.05 (ETS 300 910): "Digital cellular telecommunications system
(Phase 2+); Radio transmission and reception".
[4] GSM 05.08 (ETS 300 911): "Digital cellular telecommunication system
(Phase 2+); Radio subsystem link control".
[5] GSM 06.02 (ETS 300 966): "Digital cellular telecommunications system
(Phase 2+); Half rate speech Part 1: Half rate speech processing functions".
[6] GSM 06.20 (ETS 300 969): "Digital cellular telecommunications system
(Phase 2+); Half rate speech; Half rate speech transcoding".
[7] GSM 06.21 (ETS 300 970): "Digital cellular telecommunications system
(Phase 2+); Half rate speech; Substitution and muting of lost frames for half rate
speech traffic channels".
[8] GSM 06.22 (ETS 300 971): "Digital cellular telecommunications system
(Phase 2+); Half rate speech; Comfort noise aspects for half rate speech traffic
channels".
[9] GSM 06.42 (ETS 300 973): "Digital cellular telecommunications system
(Phase 2+); Half rate speech; Voice Activity Detector (VAD) for half rate speech
traffic channels".
[10] GSM 08.61 (ETS 300 979): "Digital cellular telecommunications system
(Phase 2+); Inband control of remote transcoders and rate adaptors for half rate
traffic channels".

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ETS 300 972 (GSM 06.41 version 5.1.1): March 1998
[11] GSM 06.06 (ETS 300 967): "Digital cellular telecommunications system
(Phase 2+); Half rate speech Part 7: ANSI-C code for the GSM half rate speech
codec".
3 Definitions, symbols and abbreviations
3.1 Definitions
For the purpose of this ETS, the following definitions apply:
accepted SID frame: A traffic frame which is flagged with SID= "1" or SID= "2" by the Radio Subsystem.
bad traffic frame: A traffic frame flagged BFI= "1" (Bad Frame Indication) or with UFI= "1" (Unreliable
Frame Indication) by the Radio Subsystem.
frame: Time interval of 20 ms corresponding to the time segmentation of the half rate speech transcoder
defined in GSM 06.20 (ETS 300 969) [6]), also used as a short term for a traffic frame.
good speech frame: A good traffic frame which is not an accepted SID frame.
good traffic frame: A traffic frame flagged BFI= "0" and UFI= "0" by the Radio Subsystem.
GS averaging period: The period in which the quantized energy tweak parameters GS are averaged: it
corresponds to the hangover period.
hangover period: A period of 7 frames added at the end of a speech burst in which VAD flag = "0" and
SP flag= "1".
invalid SID frame: An accepted SID frame which was not classified as valid SID frame. This frame is not
valid for updating comfort noise parameters, but the frame conveys information that comfort noise
generations should be started or continued.
lost SID frame: An unusable frame received when the RX DTX Handler is generating comfort noise and a
SID frame is expected (Time Alignment Flag TAF= "1").
lost speech frame: An unusable frame received when the RX DTX Handler is passing on traffic frames
directly to the speech decoder.
SID code word: Fixed bit pattern defined in GSM 06.22 (ETS 300 971) [8], for labelling a traffic frame as
a SID frame.
SID field: The bit positions defined in GSM 06.22 (ETS 300 971) [8], of the SID codeword within a SID
frame.
SID frame: Frame characterised by the SID (Silence Descriptor) code word. It conveys information on the
acoustic background noise.
SP flag: Boolean flag, generated by the TX DTX handler, indicating the presence of a speech fr
...