1、 ETSI TS 1Digital cellular telecoFComfort noise aspect(3GPP TS 46.0TECHNICAL SPECIFICATION146 012 V13.0.0 (2016communications system (PhaFull rate speech; ct for full rate speech traffic c.012 version 13.0.0 Release 13GLOBAL SYSTEMOBILE COMMUN16-01) hase 2+); c channels 13) TEM FOR ICATIONSRETSI ETS
2、I TS 146 012 V13.0.0 (2016-01)13GPP TS 46.012 version 13.0.0 Release 13Reference RTS/TSGS-0446012vd00 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 enr
3、egistre 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 d
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5、ithin ETSI Secretariat. 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 http:/portal.etsi.org/tb/status/status.asp If you find errors in the present docu
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7、itten 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 2016. All rights reserved. DECTTM, PLUGTESTSTM, U
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9、TSI TS 146 012 V13.0.0 (2016-01)23GPP TS 46.012 version 13.0.0 Release 13Intellectual 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
10、 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.org/).
11、 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 presen
12、t 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 refer
13、ences 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 V13.0.0 (2016-01)33GPP TS 46.012 ver
15、sion 13.0.0 Release 13Contents 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 encodin
16、g . 6g36 Functions on the receive side . 7g36.1 Comfort noise generation and updating 7g3Annex A (informative): Change history . 8g3History 9g3ETSI ETSI TS 146 012 V13.0.0 (2016-01)43GPP TS 46.012 version 13.0.0 Release 13Foreword This Technical Specification has been produced by the 3rdGeneration P
17、artnership 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
18、increase 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 enhanc
19、ements, corrections, updates, etc. z the third digit is incremented when editorial only changes have been incorporated in the document. ETSI ETSI TS 146 012 V13.0.0 (2016-01)53GPP TS 46.012 version 13.0.0 Release 131 Scope The present document gives the detailed requirements for the correct operatio
20、n 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
21、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 References The following documents contain provisions which, through reference in this text, con
22、stitute 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
23、a 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: “Di
24、gital 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
25、rate 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
26、 is 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
27、 has 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
28、noise 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
29、of the noise on the transmit side. ETSI ETSI TS 146 012 V13.0.0 (2016-01)63GPP TS 46.012 version 13.0.0 Release 135 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
30、in 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 acoust
32、ic 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 Rat
33、io 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
34、 parameters 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
35、of 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 en
36、coded 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
37、remaining bits in the SID frame are set to zero. The use of these bits is for further study. ETSI ETSI TS 146 012 V13.0.0 (2016-01)73GPP TS 46.012 version 13.0.0 Release 136 Functions on the receive side The situations in which comfort noise shall be generated on the receive side are defined in GSM
38、06.31 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 gener
39、ated, 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
40、 LTP 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
41、parameters, 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 shou
42、ld preferably be interpolated over a few frames to obtain smooth transitions. ETSI ETSI TS 146 012 V13.0.0 (2016-01)83GPP TS 46.012 version 13.0.0 Release 13Annex A (informative): Change history Change history SMG No. TDoc. No. CR. No. Section affected New version Subject/Comments SMG#07 4.0.4 ETSI
43、Publication 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 0
44、6-2001 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
45、 9.0.0 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 ETSI ETSI TS 146 012 V13.0.0 (2016-01)93GPP TS 46.012 version 13.0.0 Release 13History Document history V13.0.0 January 2016 Publication
