1、 ETSI TS 146 081 V14.0.0 (2017-04) Digital cellular telecommunications system (Phase 2+) (GSM); Discontinuous Transmission (DTX) for Enhanced Full Rate (EFR) speech traffic channels (3GPP TS 46.081 version 14.0.0 Release 14) TECHNICAL SPECIFICATION GLOBAL SYSTEM FOR MOBILE COMMUNICATIONSRETSI ETSI T
2、S 146 081 V14.0.0 (2017-04)13GPP TS 46.081 version 14.0.0 Release 14Reference RTS/TSGS-0446081ve00 Keywords GSM ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16 Siret N 348 623 562 00017 - NAF 742 C Association but non lucratif enregi
3、stre la Sous-Prfecture de Grasse (06) N 7803/88 Important notice The present document can be downloaded from: http:/www.etsi.org/standards-search The present document may be made available in electronic versions and/or in print. The content of any electronic and/or print versions of the present docu
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9、 ETSI ETSI TS 146 081 V14.0.0 (2017-04)23GPP TS 46.081 version 14.0.0 Release 14Intellectual 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 memb
10、ers 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 (https:/ipr.etsi
11、.org/). 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
12、 present document. Foreword This Technical Specification (TS) has been produced by ETSI 3rd Generation Partnership Project (3GPP). The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or GSM identities. These should be interpreted as bein
13、g references to the corresponding ETSI deliverables. The cross reference between GSM, UMTS, 3GPP and ETSI identities can be found under http:/webapp.etsi.org/key/queryform.asp. Modal verbs terminology In the present document “shall“, “shall not“, “should“, “should not“, “may“, “need not“, “will“, “w
14、ill not“, “can“ and “cannot“ are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of provisions). “must“ and “must not“ are NOT allowed in ETSI deliverables except when used in direct citation. ETSI ETSI TS 146 081 V14.0.0 (2017-04)33GPP TS 46.
15、081 version 14.0.0 Release 14Contents Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 4g31 Scope 5g32 References 5g33 Definitions, symbols and abbreviations . 6g33.1 Definitions 6g33.2 Symbols 7g33.3 Abbreviations . 7g34 General . 7g34.1 General organization 7g35
16、Transmit (TX) side . 8g35.1 General operation . 8g35.1.1 Functions of the TX DTX handler 8g35.1.2 Functions of the TX Radio Subsystem . 10g36 Receive (RX) side 11g36.1 General operation . 11g36.1.1 Functions of the RX radio subsystem . 11g36.1.2 Functions of the RX DTX handler 12g3Annex A (informati
17、ve): Change history . 13g3History 14g3ETSI ETSI TS 146 081 V14.0.0 (2017-04)43GPP TS 46.081 version 14.0.0 Release 14Foreword This Technical Specification has been produced by the 3rdGeneration Partnership Project (3GPP). The present document describes the general baseband operation of Enhanced Full
18、 Rate speech traffic channels in the transmitter and in the receiver of GSM Mobile Stations and Base Station Systems during Discontinuous Transmission (DTX) within the digital cellular telecommunications system. The contents of the present document are subject to continuing work within the TSG and m
19、ay change following formal TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an identifying change of release date and an increase in version number as follows: Version x.y.z where: x the first digit: 1 presented to TSG for information;
20、2 presented to TSG for approval; 3 or greater indicates TSG approved document under change control. y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections, updates, etc. z the third digit is incremented when editorial only changes have been incorpora
21、ted in the document. ETSI ETSI TS 146 081 V14.0.0 (2017-04)53GPP TS 46.081 version 14.0.0 Release 141 Scope The present document gives a description of the general baseband operation of Enhanced Full Rate speech traffic channels in the transmitter and in the receiver of GSM Mobile Stations (MS)s and
22、 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 next, this structure of distributing the various functions between system entities is not mandatory for im
23、plementation, 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 Sys
24、tem (RSS) as described in the present document together with all their flags is mandatory, being part of the A-bis interface as described in GSM 08.60 13. The DTX functions described in the present document are mandatory for implementation in the GSM MSs. The receiver requirements are mandatory for
25、implementation in all GSM BSSs, the transmitter requirements only for those where downlink DTX will be used. 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 dat
26、e 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. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitl
27、y refers to the latest version of that document in the same Release as the present document. 1 GSM 01.04: “Digital cellular telecommunications system (Phase 2+); Abbreviations and acronyms“. 2 GSM 04.08: “Digital cellular telecommunications system (Phase 2+); Mobile radio interface layer 3 specifica
28、tion“. 3 GSM 05.03: “Digital cellular telecommunications system (Phase 2+); Channel coding“. 4 GSM 05.05: “Digital cellular telecommunications system (Phase 2+); Radio transmission and reception“. 5 GSM 05.08: “Digital cellular telecommunications system (Phase 2+); Radio subsystem link control“. 6 G
29、SM 06.51: “Digital cellular telecommunications system (Phase 2+); Enhanced Full Rate (EFR) speech processing functions; General description“. 7 GSM 06.53: “Digital cellular telecommunications system (Phase 2+); ANSI-C code for the GSM Enhanced Full Rate (EFR) speech codec“. 8 GSM 06.54: “Digital cel
30、lular telecommunications system (Phase 2+); Test vectors for the GSM Enhanced Full Rate (EFR) speech codec“. 9 GSM 06.60: “Digital cellular telecommunications system (Phase 2+); Enhanced Full Rate (EFR) speech transcoding“. 10 GSM 06.61: “Digital cellular telecommunications system (Phase 2+); Substi
31、tution and muting of lost frame for Enhanced Full Rate (EFR) speech traffic channels“. ETSI ETSI TS 146 081 V14.0.0 (2017-04)63GPP TS 46.081 version 14.0.0 Release 1411 GSM 06.62: “Digital cellular telecommunications system (Phase 2+); Comfort noise aspects for Enhanced Full Rate (EFR) speech traffi
32、c channels“. 12 GSM 06.82: “Digital cellular telecommunications system (Phase 2+); Voice Activity Detector (VAD) for Enhanced Full Rate (EFR) speech traffic channels“. 13 GSM 08.60: “Digital cellular telecommunications system (Phase 2+); Inband control of remote transcoders and rate adaptors for Enh
33、anced Full Rate (EFR) and full rate traffic channels“. 3 Definitions, symbols and abbreviations 3.1 Definitions For the purposes of the present document, the following terms and definitions apply: accepted SID frame: traffic frame which is flagged with SID=“1“ or SID=“2“ by the Radio Subsystem. bad
34、traffic frame: traffic frame flagged BFI flag =“1“ (Bad Frame Indication) by the Radio Subsystem. frame: time interval of 20 msec. corresponding to the time segmentation of the Enhanced Full Rate speech transcoder (GSM 06.60 9), also used as a short term for a traffic frame. good speech frame: good
35、traffic frame which is not an accepted SID frame. good traffic frame: traffic frame flagged BFI flag =“0“ by the Radio Subsystem. hangover period: period of 7 frames added at the end of a speech burst in which VAD flag =“0“ and SP flag =“1“. invalid SID frame: accepted SID frame which was not classi
36、fied 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: unusable frame received when the RX DTX handler is generating comfort noise and a SID frame is expe
37、cted (Time Alignment Flag, TAF=“1“). lost speech frame: 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 06.62 11, for labelling a traffic frame as a SID frame. SID field: bit positions define
38、d in GSM 06.62 11, of the SID codeword within a SID frame. SID frame: frame characterized 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 frame (“1“) or the
39、 presence of a SID frame (“0“). speech frame: traffic frame that cannot be classified as a SID frame. TAF flag: Time Alignment Flag. Boolean flag, marks with TAF=1 those traffic frames that are aligned with the SACCH multiframe structure (see GSM 05.08 5). The next SID frame is expected at the decod
40、er when TAF=1. traffic frame: block of 244 information bits transmitted on the Enhanced Full Rate speech traffic channel. unusable frame: bad traffic frame that is not an accepted SID frame. VAD flag: boolean flag, generated by the VAD algorithm defined in GSM 06.82 12 indicating the presence (“1“)
41、or the absence (“0“) of a speech frame. valid SID frame: good traffic frame flagged with SID=“2“ by the Radio Subsystem. This frame is valid for updating of comfort noise parameters at any time. ETSI ETSI TS 146 081 V14.0.0 (2017-04)73GPP TS 46.081 version 14.0.0 Release 143.2 Symbols For the purpos
42、es of the present document, the following symbol applies: NelapsedNumber of elapsed frames since the last updated SID frame. 3.3 Abbreviations For the purposes of the present document, the following abbreviations apply: BFI Bad Frame Indicator BSC Base Station Controller BSS Base Station System DTX
43、Discontinuous Transmission ETS European Telecommunication Standard FACCH Fast Associated Control CHannel GSM Global System for Mobile Telecommunications MS Mobile StationRSS Radio Sub System RX Receive SACCH Slow Associated Control CHannel SID SIlence Descriptor TX Transmit VAD Voice Activity Detect
44、or For abbreviations not given in this clause, see GSM 01.04 1. 4 General Discontinuous Transmission (DTX) is a mechanism which allows the radio transmitter to be switched off most of the time during speech pauses for the following two purposes: - to save power in the Mobile Station (MS); - to reduc
45、e the overall interference level over the air interface; DTX shall be in operation in GSM MS if commanded so by the network, see GSM 04.08 2. 4.1 General organization The overall DTX mechanism described in the present document requires the following functions: - a Voice Activity Detector (VAD) on th
46、e transmit (TX) side; - evaluation of the background acoustic noise on the transmit (TX) side, in order to transmit characteristic parameters to the receive (RX) side; - generation on the receive (RX) side of a similar noise, called comfort noise, during periods where the radio transmission is switc
47、hed off. The Voice Activity Detector (VAD) is defined in GSM 06.82 12 and the comfort noise functions in GSM 06.62 11. Both are based partly on the speech transcoder and its internal variables, defined in GSM 06.60 9. In addition to these functions, if the parameters arriving at the RX side are dete
48、cted to be seriously corrupted by errors, the speech or comfort noise must be generated from substituted data in order to avoid seriously annoying effects for the listener. This function is defined in GSM 06.61 10. An overall description of the speech processing parts can be found in GSM 06.51 6. ET
49、SI ETSI TS 146 081 V14.0.0 (2017-04)83GPP TS 46.081 version 14.0.0 Release 145 Transmit (TX) side A block diagram of the transmit side DTX functions is shown in figure 1. SpeechencoderVoiceActivityDetectorComfortNoiseComputationChannelEncodingSP flagmonitoringInformation bitsSP flag2441TX DTX handler TX radio subsystemFigure 1: Block diagram of the transmit side DTX functions 5.1 General operation The TX DTX handler continuously passes traffic frames, individually marked by a flag SP, to the Radio Subsystem (RSS). This b
