1、 ETSI TS 146 012 V14.0.0 (2017-04) Digital cellular telecommunications system (Phase 2+) (GSM); Full rate speech; Comfort noise aspect for full rate speech traffic channels (3GPP TS 46.012 version 14.0.0 Release 14) TECHNICAL SPECIFICATION GLOBAL SYSTEM FOR MOBILE COMMUNICATIONSRETSI ETSI TS 146 012
2、 V14.0.0 (2017-04)13GPP TS 46.012 version 14.0.0 Release 14Reference RTS/TSGS-0446012ve00 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 enregistre la S
3、ous-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 document shal
4、l not be modified without the prior written authorization of ETSI. In case of any existing or perceived difference in contents between such versions and/or in print, the only prevailing document is the print of the Portable Document Format (PDF) version kept on a specific network drive within ETSI S
5、ecretariat. 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 https:/portal.etsi.org/TB/ETSIDeliverableStatus.aspx If you find errors in the present docume
6、nt, please send your comment to one of the following services: https:/portal.etsi.org/People/CommiteeSupportStaff.aspx Copyright Notification No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm except as authorized by writ
7、ten permission of ETSI. The content of the PDF version shall not be modified without the written authorization of ETSI. The copyright and the foregoing restriction extend to reproduction in all media. European Telecommunications Standards Institute 2017. All rights reserved. DECTTM, PLUGTESTSTM, UMT
8、STMand the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members. 3GPPTM and LTE are Trade Marks of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners. GSM and the GSM logo are Trade Marks registered and owned by the GSM Association. ETSI ETS
9、I TS 146 012 V14.0.0 (2017-04)23GPP TS 46.012 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 members and n
10、on-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.org/). P
11、ursuant 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
12、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 being referen
13、ces 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“, “will not“,
14、 “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 146 012 V14.0.0 (2017-04)33GPP TS 46.012 versi
15、on 14.0.0 Release 14Contents Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 4g31 Scope 5g32 References 5g33 Definitions and abbreviations . 5g34 General . 5g35 Functions on the transmit side 6g35.1 Background acoustic noise evaluation . 6g35.2 SID-frame encoding
16、. 6g36 Functions on the receive side . 7g36.1 Comfort noise generation and updating 7g3Annex A (informative): Change history . 8g3History 9g3ETSI ETSI TS 146 012 V14.0.0 (2017-04)43GPP TS 46.012 version 14.0.0 Release 14Foreword This Technical Specification has been produced by the 3rdGeneration Par
17、tnership Project (3GPP). The contents of the present document are subject to continuing work within the TSG and may 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 in
18、crease in version number as follows: Version x.y.z where: x the first digit: 1 presented to TSG for information; 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 enhancem
19、ents, corrections, updates, etc. z the third digit is incremented when editorial only changes have been incorporated in the document. ETSI ETSI TS 146 012 V14.0.0 (2017-04)53GPP TS 46.012 version 14.0.0 Release 141 Scope The present document gives the detailed requirements for the correct operation
20、of the background acoustic noise evaluation, noise parameter encoding/decoding and comfort noise generation in GSM Mobile Stations (MS)s and Base Station Systems (BSS)s during Discontinuous Transmission (DTX) on full rate speech traffic channels. The requirements described in the present document ar
21、e 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 References The following documents contain provisions which, through reference in this text, const
22、itute 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. In the case of a
23、reference to a 3GPP document (including a GSM document), a non-specific reference implicitly 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 05.03: “Digi
24、tal cellular telecommunications system (Phase 2+); Channel coding“. 3 GSM 06.10: “Digital cellular telecommunications system (Phase 2+); Full rate speech; Transcoding“. 4 GSM 06.31: “Digital cellular telecommunications system (Phase 2+); Full rate speech; Discontinuous Transmission (DTX) for full ra
25、te speech traffic channel“. 3 Definitions and abbreviations Definitions and abbreviations used in the present document are listed in GSM 01.04 1. The definitions of terms used in this technical specification can be found in GSM 06.31 4. 4 General The overall operation of Discontinuous Transmission i
26、s described in GSM 06.31 4. A basic problem when using DTX is that the background acoustic noise, which is transmitted together with the speech, would disappear when the radio transmission is cut, resulting in a modulation of the background noise. Since the DTX switching can take place rapidly, it h
27、as been found that this effect can be very annoying for the listener - especially in a car environment with high background noise levels. In bad cases the speech may be hardly intelligible. The present document specifies the way to overcome this problem by generating on the receive side synthetic no
28、ise similar to the transmit side background noise. The parameters of this so called comfort noise are estimated on the transmit side and transmitted to the receive side before the radio transmission is cut and at a regular low rate afterwards. This allows the comfort noise to adapt to the changes of
29、 the noise on the transmit side. ETSI ETSI TS 146 012 V14.0.0 (2017-04)63GPP TS 46.012 version 14.0.0 Release 145 Functions on the transmit side The comfort noise evaluation algorithm uses the unquantized block amplitude and Log Area Ratio (LAR) parameters of the full rate speech encoder, defined in
30、 subclauses 4.2.15 and 4.2.6 of GSM 06.10 3. These parameters give information on the level and the spectrum of the background noise, respectively. The evaluated comfort noise parameters are encoded into a special frame, called a SID (Silence Descriptor) frame, for transmission to the receive side.
31、The SID frame also serves to initiate the comfort noise generation on the receive side, as a SID frame is always sent at the end of a speech burst, i.e. before the radio transmission is cut. The scheduling of SID or speech frames on the radio path is described in GSM 06.31 4. 5.1 Background acoustic
32、 noise evaluation The comfort noise parameters to be encoded into a SID frame are calculated over N=4 consecutive frames marked with VAD=0, as follows: The Log Area Ratio parameters shall be averaged according to the equation: =NninjLARNiLARmean1)(1)( i = 1,28 where LARj(i) is the ith Log Area Ratio
33、 coefficient of the current frame j and j-n indicates the previous frames. The block amplitude parameter shall be averaged according to the equation: =NniinjxNxmean141maxmax)()4(1)( where xmaxj(i) is the block amplitude in sub-segment i of the current frame. The SID frame containing these averaged p
34、arameters is passed to the Radio Subsystem instead of frame number j. 5.2 SID-frame encoding The SID-frame encoding algorithm exploits the fact that only some of the 260 bits in a frame are needed to code the comfort noise parameters. The other bits can then be used to mark the SID-frame by means of
35、 a fixed bit pattern, called the SID code word. The log area ratio coefficients are replaced by the mean (LAR(i) values defined above and encoded as described in GSM 06.10 3. The block amplitude values are replaced by the mean (xmax) value defined above, repeated four times inside the frame and enco
36、ded as described in GSM 06.10 3. The SID code word consists of 95 bits which are all zero. The bits of the SID code word are inserted in the SID field defined as the positions of those 95 bits of the encoded RPE-pulses Xmc, which are in the error protection class I (see GSM 05.03 2, table 2). The re
37、maining bits in the SID frame are set to zero. The use of these bits is for further study. ETSI ETSI TS 146 012 V14.0.0 (2017-04)73GPP TS 46.012 version 14.0.0 Release 146 Functions on the receive side The situations in which comfort noise shall be generated on the receive side are defined in GSM 06
38、.31 4. Generally speaking, the comfort noise generation is started or updated whenever a valid SID frame is received. 6.1 Comfort noise generation and updating The comfort noise generation procedure uses the RPE-LTP speech decoder algorithm defined in GSM 06.10 3. When comfort noise is to be generat
39、ed, then the various encoded parameters are set as follows. The RPE pulses (Xmcr) are replaced by a locally generated random integer sequence, uniformly distributed between 1 and 6. Also the grid position parameters (Mcr) are set to random integer values, uniformly distributed between 0 and 3. The L
40、TP gain values (bcr) are set to 0. The LTP lag values (Ncr) of the 4 sub-segments are set to 40, 120, 40 and 120 respectively. The 4 block amplitude values (Xmaxcr) used are those received in the SID frame. The log area ratio parameters (LARcr) used are those received in the SID frame. With these pa
41、rameters, the speech decoder now performs the standard operations described in GSM 06.10 3 and synthesizes comfort noise. Updating of the comfort noise parameters occurs each time a valid SID frame is received, as described in GSM 06.31 4. When updating the comfort noise, the parameters above should
42、 preferably be interpolated over a few frames to obtain smooth transitions. ETSI ETSI TS 146 012 V14.0.0 (2017-04)83GPP TS 46.012 version 14.0.0 Release 14Annex A (informative): Change history Change history SMG No. TDoc. No. CR. No. Section affected New version Subject/Comments SMG#07 4.0.4 ETSI Pu
43、blication SMG#20 5.0.1 Release 1996 version SMG#27 6.0.0 Release 1997 version SMG#29 7.0.0 Release 1998 version 7.0.1 Version update to 7.0.1 for Publication SMG#31 8.0.0 Release 1999 version Change history Date TSG # TSG Doc. CR Rev Subject/Comment Old New 03-2001 11 Version for Release 4 4.0.0 06-
44、2001 12 SP-010304 001 Corrections of the formula for averaging Xmax 4.0.0 4.1.0 06-2002 16 Version for Release 5 4.1.0 5.0.0 12-2006 26 Version for Release 6 5.0.0 6.0.0 06-2007 36 Version for Release 7 6.0.0 7.0.0 12-2008 42 Version for Release 8 7.0.0 8.0.0 12-2009 46 Version for Release 9 8.0.0 9
45、.0.0 03-2011 51 Version for Release 10 9.0.0 10.0.0 09-2012 57 Version for Release 11 10.0.0 11.0.0 09-2014 65 Version for Release 12 11.0.0 12.0.0 12-2015 70 Version for Release 13 12.0.0 13.0.0 Change history Date Meeting TDoc CR Rev Cat Subject/Comment New version 03-2017 SA#75 Version for Release 14 14.0.0 ETSI ETSI TS 146 012 V14.0.0 (2017-04)93GPP TS 46.012 version 14.0.0 Release 14History Document history V14.0.0 April 2017 Publication
