SIST ETS 300 966 E1:2003

• Abstract:

  This European Telecommunication Standard (ETS) is an introduction to G SM 06.20 (ETS 300 969) [4], GSM 06.21 (ETS 300 970) [5], GSM 06.22 (ET S 300 971) [6], GSM 06.41 (ETS 300 972) [7] and GSM 06.42 (ETS 300 973 ) [8] ETSs dealing with the speech processing functions in the half-ra te channel of the GSM system. A general overview of the speech process ing 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 300 966 ed.1 (1997-05) - Digital cellular telecommunications system; Half rate speech; Half rate speech processing functions (GSM 06.02 version 5.0.1)

SIST ETS 300 966 E1:2003 is the Slovenian adoption of ETS 300 966 Edition 1, published by SIST and based on an ETSI European Telecommunications Standard. It gives a general overview of the half rate speech processing functions used in the GSM digital cellular telecommunications system and points to the related ETSs that define each function in detail. It is intended for people who need to understand the half-rate speech path before implementing, testing, or integrating the detailed GSM 06.xx parts.

What does SIST ETS 300 966 E1:2003 specify?

SIST ETS 300 966 E1:2003 is an introduction to the GSM half-rate speech processing chain. It explains how the speech functions in the half-rate channel are organized and identifies the companion standards that specify each function more precisely.

The document is structured as a short overview:

• Clause 1 gives the scope.
• Clause 2 lists the normative references.
• Clause 3 gives definitions and abbreviations.
• Clause 4 presents the general reference configuration.
• Clauses 5 to 10 describe the main half-rate speech processing functions.

What are the key requirements of SIST ETS 300 966 E1:2003?

SIST ETS 300 966 E1:2003 mainly describes how the half-rate speech path is divided into functions and how those functions interact. In practice, it tells implementers what blocks exist, what signals pass between them, and which companion ETS to consult for the detailed algorithm.

Clause 4 - reference configuration

Clause 4 sets out a reference configuration for the audio path between the Mobile Station (MS) and the Public Switched Telephone Network (PSTN). It shows that the audio parts are included only to the extent that their performance affects the speech transcoder. This matters because the speech chain has to be considered as a complete path, not as isolated blocks.

Clause 5 - half rate speech transcoding

Clause 5 identifies GSM 06.20 as the detailed description of half-rate speech transcoding. It states that the encoder works from 13 bit uniform Pulse Code Modulated (PCM) speech and that the codec uses Vector Sum Excited Linear Predictor (VSELP) coding. It also ties the codec output to channel coding in GSM 05.03. In practice, this tells designers the frame sizes, sample rate, and where codec output goes in the GSM channel chain.

Clause 6 - Half rate Discontinuous Transmission (DTX)

Clause 6 explains that DTX turns the transmitter on only for frames that carry useful information. It links DTX to three functions:

• Voice Activity Detection (VAD) on the transmit side
• background noise evaluation and SID frame generation
• comfort noise generation on the receive side

This matters because DTX is used to extend battery life and reduce average RF interference, while still keeping the call sounding natural during pauses.

Clause 7 - Half rate Voice Activity Detection (VAD)

Clause 7 says that VAD uses parameters from the half-rate speech encoder to decide whether each 20 ms frame contains speech. The VAD flag feeds the TX DTX handler, but it does not key the transmitter directly. In practice, implementers need to route the VAD output through the DTX handling logic, not straight to transmitter control.

Clause 8 - Half rate comfort noise insertion

Clause 8 describes comfort noise as the artificial noise added at the receiver during speech pauses. The process uses background-noise evaluation, SID frame encoding and decoding, and comfort noise generation. This reduces the sudden drop in background noise that can be distracting to listeners.

Clause 9 - Half rate lost speech frame substitution and muting

Clause 9 says that isolated lost speech frames are replaced by predicted frames, while several consecutive losses are handled by muting. It also notes that silent frame insertion is not allowed. In practice, this is the speech error-concealment method used when frames are lost in transmission.

Clause 10 - Half rate codec homing

Clause 10 defines homing behavior for the bit-exact parts of the half-rate speech transcoder, VAD, DTX system, and comfort noise parts. It supports type approval, remote control, and maintenance testing by forcing modules back to a known home state with special homing frames.

What terms does SIST ETS 300 966 E1:2003 define?

SIST ETS 300 966 E1:2003 uses a small set of abbreviations that are central to the half-rate speech chain:

• DTX - Discontinuous Transmission, where the transmitter is active only for useful speech or control frames.
• VAD - Voice Activity Detector, which decides whether a frame contains speech.
• SID - Silence Descriptor, a frame used to carry comfort-noise information.
• SP - Speech flag, which indicates whether transmitted information is speech or SID information.
• BFI - Bad Frame Indication, a flag used when a received frame is considered bad.
• UFI - Unreliable Frame Indication, used to mark unreliable received information.
• TAF - Time Alignment Flag, which marks the position of a SID frame in the SACCH multiframe.

Who uses SIST ETS 300 966 E1:2003?

SIST ETS 300 966 E1:2003 is used by GSM speech codec developers, mobile station designers, base station and radio subsystem engineers, and test laboratories. It is also relevant to type approval and maintenance teams that need to verify bit-exact behavior, homing functions, and the way DTX-related frames are handled across the speech path.

What changed in SIST ETS 300 966 E1:2003 from the previous edition?

SIST ETS 300 966 E1:2003 is identical to ETS 300 966 Edition 1. The Slovenian standard therefore carries the same technical content and structure as that edition.

Which standards are used with SIST ETS 300 966 E1:2003?

Reference	What it contributes
GSM 01.04	Abbreviations and acronyms used across GSM documents
GSM 03.50	Speech services transmission planning aspects in the GSM PLMN system
GSM 05.03	Channel coding for the speech stream
GSM 06.20	Half rate speech transcoding
GSM 06.21	Substitution and muting of lost frames
GSM 06.22	Comfort noise aspects
GSM 06.41	Discontinuous Transmission (DTX) for half rate speech traffic channels
GSM 06.42	Voice Activity Detector (VAD) for half rate speech traffic channels
ITU-T G.711	Pulse Code Modulation of voice frequencies
GSM 06.07	Test sequences for the GSM half rate speech codec
GSM 06.06	ANSI-C code for the GSM half rate speech codec

What does the SIST ETS 300 966 E1:2003 document contain?

The document contains a general reference figure showing the transmit and receive speech processing path, including the MS, BSS, PSTN interface, and the flags used by DTX-related functions. It also gives the main frame types and signal labels used in the half-rate speech chain, such as encoded speech frames, SID frames, SP, BFI, TAF, and UFI. The text then explains how the main functions relate to the companion GSM 06.xx standards. Its final pages include the document history and publication information.

SLOVENSKI STANDARD
01-december-2003
'LJLWDOQLFHOLþQLWHOHNRPXQLNDFLMVNLVLVWHP±*RYRUVSROKLWURVWL±)XQNFLMH]D
REGHODYRJRYRUDVSROKLWURVWL*60UD]OLþLFD
Digital cellular telecommunications system; Half rate speech; Half rate speech
processing functions (GSM 06.02 version 5.0.1)
Ta slovenski standard je istoveten z: ETS 300 966 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 300 966
TELECOMMUNICATION May 1997
STANDARD
Source: ETSI TC-SMG Reference: DE/SMG-110602Q
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;
Half rate speech;
Half rate speech processing functions
(GSM 06.02 version 5.0.1)
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
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.

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ETS 300 966 (GSM 06.02 version 5.0.1): May 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.

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ETS 300 966 (GSM 06.02 version 5.0.1): May 1997
Contents
Foreword .5
1 Scope .7
2 Normative references.7
3 Definitions and abbreviations .8
3.1 Definitions .8
3.2 Abbreviations .8
4 General.9
5 Half rate speech transcoding .10
6 Half rate Discontinuous Transmission (DTX).10
7 Half rate Voice Activity Detection (VAD) .11
8 Half rate comfort noise insertion .11
9 Half rate lost speech frame substitution and muting .11
10 Half rate codec homing .12
History.13

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ETS 300 966 (GSM 06.02 version 5.0.1): May 1997
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ETS 300 966 (GSM 06.02 version 5.0.1): May 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 gives a general overview of the half rate speech traffic channels speech processing functions for
the digital cellular telecommunications system. 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; Half rate
speech; Half rate speech processing functions".
GSM 06.20 ETS 300 969: "Digital cellular telecommunications system; Half rate speech;
Half rate speech transcoding".
GSM 06.21 ETS 300 970: "Digital cellular telecommunications system; 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; Half rate speech;
Comfort noise aspects for half rate speech traffic channels".
GSM 06.41 ETS 300 972: "Digital cellular telecommunications system; Half rate speech;
Discontinuous Transmission (DTX) for half rate speech traffic channels".
GSM 06.42 ETS 300 973: "Digital cellular telecommunications system; Half rate speech;
Voice Activity Detector (VAD) for half rate speech traffic channels".
GSM 06.06 ETS 300 967: "Digital cellular telecommunications system; Half rate speech;
ANSI-C code for the GSM half rate speech codec".
GSM 06.07 ETS 300 968: "Digital cellular telecommunications system; Half rate speech;
Test sequences for the GSM half rate speech codec".
Transposition dates
Date of adoption: 4 April 1997
Date of latest announcement of this ETS (doa): 31 August 1997
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 28 February 1998
Date of withdrawal of any conflicting National Standard (dow): 28 February 1998

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ETS 300 966 (GSM 06.02 version 5.0.1): May 1997
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ETS 300 966 (GSM 06.02 version 5.0.1): May 1997
1 Scope
This European Telecommunication Standard (ETS) is an introduction to GSM 06.20 (ETS 300 969) [4],
GSM 06.21 (ETS 300 970) [5], GSM 06.22 (ETS 300 971) [6], GSM 06.41 (ETS 300 972) [7] and
GSM 06.42 (ETS 300 973) [8] ETSs dealing with the speech processing functions in the half-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 350): "Digital cellular telecommunications system (Phase 2+);
Abbreviations and acronyms".
[2] GSM 03.50 (ETS 300 903): "Digital cellular telecommunications system
(Phase 2+); Transmission planning aspects of the speech services in the GSM
Public Land Mobile Network (PLMN) system".
[3] GSM 05.03 (ETS 300 909): "Digital cellular telecommunications system
(Phase 2+); Channel coding".
[4] GSM 06.20 (ETS 300 969): "Digital cellular telecommunications system; Half
rate speech: Half rate speech transcoding".
[5] GSM 06.21 (ETS 300 970): " Digital cellular telecommunications system; Half
rate speech; Substitution and muting of lost frame for half rate speech traffic
channels".
[6] GSM 06.22 (ETS 300 971): "Digital cellular telecommunications system; Half
rate speech; Comfort noise aspects for half rate speech traffic channels ".
[7] GSM 06.41 (ETS 300 972): "Digital cellular telecommunications system; Half
rate speech; Discontinuous transmission (DTX) for half rate speech traffic
channels".
[8] GSM 06.42 (ETS 300 973): "Digital cellular telecommunications system; Half
rate speech; Voice Activity Detector (VAD) for half rate speech traffic channels ".
[9] ITU-T Recommendation G.711: "Pulse Code Modulation (PCM) of voice
frequencies".
[10] GSM 06.07 (ETS 300 968): "Digital cellular telecommunications system; Half
rate speech; Test sequences for the GSM half rate speech codec".
[11] GSM 06.06 (ETS 300 967): "Digital cellular telecommunications system; Half
rate speech; ANSI-C code for the GSM half rate speech codec".

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ETS 300 966 (GSM 06.02 version 5.0.1): May 1997
3 Definitions and abbreviations
3.1 Definitions
Definition of terms used in this ETS can be found in GSM 06.20 (ETS 300 969) [4],
GSM 06.21 (ETS 300 970) [5], GSM 06.22 (ETS 300 971) [6], GSM 06.41 (ETS 300 972) [7] and
GSM 06.42 (ETS 300 973) [8].
3.2 Abbreviations
For the purposes of this ETS, the following abbreviations apply:
BFI Bad Frame Indication
BSS Base Station System
DTX Discontinuous Transmission
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
RX Receive
RSS Radio SubSystem
SACCH Slow Associated Control CHannel
SID SIlence Descriptor
SP flag SPeech flag
TAF Time Alignment Flag
TX Transmit
VSELP Vector Sum Excited Linear Predictor
UFI Unreliable Frame Indication
For abbreviations not given in this subclause, see GSM 01.04 (ETR 100) [1].

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ETS 300 966 (GSM 06.02 version 5.0.1): May 1997
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 fig
...