ETSI TS 146 042-2017 Digital cellular telecommunications system (Phase 2+) (GSM) Half rate speech Voice Activity Detector (VAD) for half rate speech traffic channels (V14 0 0 3GPP .pdf

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1、 ETSI TS 146 042 V14.0.0 (2017-04) Digital cellular telecommunications system (Phase 2+) (GSM); Half rate speech; Voice Activity Detector (VAD) for half rate speech traffic channels (3GPP TS 46.042 version 14.0.0 Release 14) TECHNICAL SPECIFICATION GLOBAL SYSTEM FOR MOBILE COMMUNICATIONSRETSI ETSI T

2、S 146 042 V14.0.0 (2017-04)13GPP TS 46.042 version 14.0.0 Release 14Reference RTS/TSGS-0446042ve00 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

4、ment shall 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 with

5、in 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 https:/portal.etsi.org/TB/ETSIDeliverableStatus.aspx If you find errors in the prese

6、nt document, 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 authorize

7、d by written 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, PLUGTES

8、TSTM, UMTSTMand 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.

9、 ETSI ETSI TS 146 042 V14.0.0 (2017-04)23GPP TS 46.042 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 146 042 V14.0.0 (2017-04)33GPP TS 46.

15、042 version 14.0.0 Release 14Contents Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 4g31 Scope 5g32 References 5g33 Definitions, symbols and abbreviations . 5g33.1 Definitions 5g33.2 Symbols 6g33.2.1 Variables . 6g33.2.2 Constants 6g33.2.3 Functions 7g33.3 Abbre

16、viations . 7g34 General . 7g35 Functional description 7g35.1 Overview and principles of operation 8g35.2 Algorithm description . 8g35.2.1 Adaptive filtering and energy computation 9g35.2.2 ACF averaging 9g35.2.3 Predictor values computation 10g35.2.4 Spectral comparison 10g35.2.5 Information tone de

17、tection 11g35.2.6 Threshold adaptation. 11g35.2.7 VAD decision . 14g35.2.8 VAD hangover addition 14g35.2.9 Periodicity detection . 14g36 Computational description overview 15g36.1 VAD modules . 15g36.2 Pseudo-floating point arithmetic 15g3Annex A (informative): VAD performance 17g3Annex B (informati

18、ve): Simplified block filtering operation . 18g3Annex C (informative): Pole frequency calculation 19g3Annex D (informative): Change history . 20g3History 21g3ETSI ETSI TS 146 042 V14.0.0 (2017-04)43GPP TS 46.042 version 14.0.0 Release 14Foreword This Technical Specification has been produced by the

19、3rdGeneration Partnership Project (3GPP). The present document specifies the Voice Activity Detector (VAD) to be used in the Discontinuous Transmission (DTX) within the digital cellular telecommunications system. The present document is part of a series covering the half rate speech traffic channels

20、 as described below: GSM 06.02 “Digital cellular telecommunications system (Phase 2+); Half rate speech; Half rate speech processing functions“. GSM 06.06 “Digital cellular telecommunications system (Phase 2+); Half rate speech; ANSI-C code for the GSM half rate speech codec“. GSM 06.07 “Digital cel

21、lular telecommunications system (Phase 2+); Half rate speech; Test sequences for the GSM half rate speech codec“. GSM 06.20 “Digital cellular telecommunications system (Phase 2+); Half rate speech; Half rate speech transcoding“. GSM 06.21 “Digital cellular telecommunications system (Phase 2+); Half

22、rate speech; Substitution and muting of lost frames for half rate speech traffic channels“. GSM 06.22 “Digital cellular telecommunications system (Phase 2+); Half rate speech; Comfort noise aspects for half rate speech traffic channels“. GSM 06.41 “Digital cellular telecommunications system (Phase 2

23、+); Half rate speech; Discontinuous Transmission (DTX) for half rate speech traffic channels“. GSM 06.42 “Digital cellular telecommunications system (Phase 2+); Half rate speech; Voice Activity Detector (VAD) for half rate speech traffic channels“. The contents of the present document are subject to

24、 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 increase in version number as follows: Version x.y.z where: x the first digit:

25、 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 enhancements, corrections, updates, etc. z the third digit is incremented when edito

26、rial only changes have been incorporated in the document. ETSI ETSI TS 146 042 V14.0.0 (2017-04)53GPP TS 46.042 version 14.0.0 Release 141 Scope The present document specifies the Voice Activity Detector (VAD) to be used in the Discontinuous Transmission (DTX) as described in GSM 06.41 4. It also sp

27、ecifies the test methods to be used to verify that a VAD implementation complies with the present document. The requirements are mandatory on any VAD to be used either in GSM Mobile Stations (MS)s or Base Station Systems (BSS)s that utilize the half-rate GSM speech traffic channel. 2 References The

28、following documents contain provisions which, through reference in this text, constitute 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

29、 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 implicitly refers to the latest version of that document in the same Release as the present document. 1 GSM 01.04: “Digital cellular te

30、lecommunications system (Phase 2+); Abbreviations and acronyms“. 2 GSM 06.20: “Digital cellular telecommunications system (Phase 2+); Half rate speech; Half rate speech transcoding“. 3 GSM 06.22: “Digital cellular telecommunications system (Phase 2+); Half rate speech; Comfort noise aspects for half

31、 rate speech traffic channels“. 4 GSM 06.41: “Digital cellular telecommunications system (Phase 2+); Half rate speech; Discontinuous Transmission (DTX) for half rate speech traffic channels“. 5 GSM 06.06: “Digital cellular telecommunications system (Phase 2+); Half rate speech; ANSI C code for the G

32、SM half rate speech codec“. 6 GSM 06.07: “Digital cellular telecommunications system (Phase 2+); Half rate speech; Test sequences for the GSM half rate speech codec“. 3 Definitions, symbols and abbreviations 3.1 Definitions For the purposes of the present document, the following terms and definition

33、s apply: mobile environment: any environment in which MSs may be used. noise: signal component resulting from acoustic environmental noise. ETSI ETSI TS 146 042 V14.0.0 (2017-04)63GPP TS 46.042 version 14.0.0 Release 143.2 Symbols For the purposes of the present document, the following symbols apply

34、: 3.2.1 Variables aav1 filter predictor values, see clause 5.2.3 acf the ACF vector which is calculated in the speech encoder (GSM 06.20 2) adaptcount secondary hangover counter, see clause 5.2.6 av0 averaged ACF vector, see clause 5.2.2 av1 a previous value of av0, see clause 5.2.2 burstcount speec

35、h burst length counter, see clause 5.2.7 den denominator of left hand side of equation 8 in annex C, see clause 5.2.5 difference difference between consecutive values of dm, see clause 5.2.4 dm spectral distortion measure, see clause 5.2.4 hangcount primary hangover counter, see clause 5.2.7 lagcoun

36、t number of subframes in current frame meeting periodicity criterion, see clause 5.2.9 lastdm previous value of dm, see clause 5.2.4 lags the open loop long term predictor lags for the four speech encoder subframes (GSM 06.20 2.) num numerator of left hand side of equation 8 in annex C, see clause 5

37、.2.5 oldlagcount previous value of lagcount, see clause 5.2.9 prederr fourth order short term prediction error, see clause 5.2.5 ptch Boolean flag indicating the presence of a periodic signal component, see clause 5.2.9 pvad energy in the current filtered signal frame, see clause 5.2.1 rav1 autocorr

38、elation vector obtained from av1, see clause 5.2.3 rc the first four unquantized reflection coefficients calculated in the speech encoder (GSM 06.20 2) rvad autocorrelation vector of the adaptive filter predictor values, see clause 5.2.6 smallag difference between consecutive lag values, see clause

39、5.2.9 stat Boolean flag indicating that the frequency spectrum of the input signal is stationary, see clause 5.2.4 thvad adaptive primary VAD threshold, see clause 5.2.6 tone Boolean flag indicating the presence of an information tone, see clause 5.2.5 vadflag Boolean VAD decision with hangover incl

40、uded, see clause 5.2.8 veryoldlagcount previous value of oldlagcount, see clause 5.2.9 vvad Boolean VAD decision before hangover, see clause 5.2.7 3.2.2 Constants adp number of frames of hangover for secondary VAD, see clause 5.2.6 burstconst minimum length of speech burst to which hangover is added

41、, see clause 5.2.8 dec determines rate of decrease in adaptive threshold, see clause 5.2.6 fac determines steady state adaptive threshold, see clause 5.2.6 frames number of frames over which av0 and av1 are calculated, see clause 5.2.2 freqth threshold for pole frequency decision, see clause 5.2.5 h

42、angconst number of frames of hangover for primary VAD, see clause 5.2.8 inc determines rate of increase in adaptive threshold, see clause 5.2.6 lthresh lag difference threshold for periodicity decision, see clause 5.2.9 margin determines upper limit for adaptive threshold, see clause 5.2.6 nthresh f

43、rame count threshold for periodicity decision, see clause 5.2.9 plev lower limit for adaptive threshold, see clause 5.2.6 predth threshold for short term prediction error, see clause 5.2.5 pth energy threshold, see clause 5.2.6 thresh decision threshold for evaluation of stat flag, clause 5.2.4 ETSI

44、 ETSI TS 146 042 V14.0.0 (2017-04)73GPP TS 46.042 version 14.0.0 Release 143.2.3 Functions + addition - subtraction * multiplication / division | x | absolute value of x AND Boolean AND OR Boolean ORb MULT(x(i) the product of the series x(i) for i=a to b i=a b SUM(x(i) the sum of the series x(i) for

45、 i=a to b i=a 3.3 Abbreviations For the purposes of the present document, the following abbreviations apply: ACF Autocorrelation Function AFLAT Autocorrelation Fixed point LAttice Technique ANSI American National Standards Institute DTX Discontinuous Transmission LTP Long Term Predictor TX Transmiss

46、ion VAD Voice Activity Detector For abbreviations not given in this clause see GSM 01.04 1. 4 General The function of the VAD is to indicate whether each 20 ms frame produced by the speech encoder contains speech or not. The output is a Boolean flag (vadflag) which is used by the Transmit (TX) DTX h

47、andler defined in GSM 06.41 4. The present document is organized as follows. Clause 5 describes the principles of operation of the VAD. Clause 6 provides an overview of the computational description of the VAD. The computational details necessary for the fixed point implementation of the VAD algorit

48、hm are given in the form of an American National Standards Institute (ANSI) C program contained in GSM 06.06 5. The verification of the VAD is based on the use of digital test sequences which are described in GSM 06.07 6. The performance of the VAD algorithm is characterized by the amount of audible

49、 speech clipping it introduces and the percentage activity it indicates. The characteristics for the VAD defined in the present document have been established by extensive testing under a wide range of operating conditions. The results are summarized in annex A. 5 Functional description The purpose of this clause is to give the reader an understanding of the principles of operation of the VAD, whereas GSM 06.06 5 contains the fixed point computational description of the VAD. In the case of discrepancy between the two descriptions, the des