1、 ETSI TS 126 451 V15.0.0 (2018-07) Universal Mobile Telecommunications System (UMTS); LTE; Codec for Enhanced Voice Services (EVS); Voice Activity Detection (VAD) (3GPP TS 26.451 version 15.0.0 Release 15) TECHNICAL SPECIFICATION ETSI ETSI TS 126 451 V15.0.0 (2018-07)13GPP TS 26.451 version 15.0.0 R
2、elease 15Reference RTS/TSGS-0426451vf00 Keywords LTE,UMTS 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 Sous-Prfecture de Grasse (06) N 7803/88 Import
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15、rg/key/queryform.asp. Modal verbs terminology In the present document “shall“, “shall not“, “should“, “should not“, “may“, “need not“, “will“, “will 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). “
16、must“ and “must not“ are NOT allowed in ETSI deliverables except when used in direct citation. ETSI ETSI TS 126 451 V15.0.0 (2018-07)33GPP TS 26.451 version 15.0.0 Release 15Contents Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 4g31 Scope 5g32 References 5g33 A
17、bbreviations . 5g34 General . 6g35 The SAD Algorithm . 6g3Annex A (informative): Change history . 7g3History 8g3ETSI ETSI TS 126 451 V15.0.0 (2018-07)43GPP TS 26.451 version 15.0.0 Release 15Foreword This Technical Specification has been produced by the 3rdGeneration Partnership Project (3GPP). The
18、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 increase in version number as f
19、ollows: 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 enhancements, corrections, updates, e
20、tc. z the third digit is incremented when editorial only changes have been incorporated in the document. ETSI ETSI TS 126 451 V15.0.0 (2018-07)53GPP TS 26.451 version 15.0.0 Release 151 Scope The present document specifies the Voice Activity Detector (VAD) used in the Discontinuous Transmission (DTX
21、) of the EVS Codec. Although the main application of the VAD algorithm is the detection of speech or voice signals, the algorithm is more accurately described as a Signal Activity Detection (SAD) algorithm. The present document is a high level overview of the functionality with reference to the Code
22、c Detailed Algorithmic Description where the functionality is specified in detail. 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 date of publication, editio
23、n 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 implicitly refers to the late
24、st version of that document in the same Release as the present document. 1 3GPP TR 21.905: “Vocabulary for 3GPP Specifications“. 2 3GPP TS 26.441: “Codec for Enhanced Voice Services (EVS); General Overview“. 3 3GPP TS 26.445: “Codec for Enhanced Voice Services (EVS); Detailed Algorithmic Description
25、 “. 4 3GPP TS 26.442: “Codec for Enhanced Voice Services (EVS); ANSI C code (fixed-point)“. 5 3GPP TS 26.443: “Codec for Enhanced Voice Services (EVS); ANSI C code (floating-point)“. 6 3GPP TS 26.444: “Codec for Enhanced Voice Services (EVS); Test Sequences“. 7 3GPP TS 26.446: “Codec for Enhanced Vo
26、ice Services (EVS); AMR-WB Backward Compatible Functions“. 8 3GPP TS 26.449: “Codec for Enhanced Voice Services (EVS); Comfort Noise Generation (CNG) Aspects“. 9 3GPP TS 26.450: “Codec for Enhanced Voice Services (EVS); Discontinuous Transmission (DTX)“. 10 3GPP TR 26.952: “Codec for Enhanced Voice
27、Services (EVS); Performance Characterization“. 3 Abbreviations For the purposes of the present document, the abbreviations given in TR 21.905 1 and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905
28、 1. ACELP Algebraic Code-Excited Linear Prediction AMR-WB Adaptive Multi Rate Wideband (codec) CNG Comfort Noise Generator DTX Discontinuous Transmission EVS Enhanced Voice Services FB Fullband FEC Frame Erasure Concealment IP Internet Protocol JBM Jitter Buffer Management ETSI ETSI TS 126 451 V15.0
29、.0 (2018-07)63GPP TS 26.451 version 15.0.0 Release 15MSB Most Significant Bit MTSI Multimedia Telephony Service for IMS NB Narrowband PS Packet SwitchedPSTN Public Switched Telephone Network SAD Signal Activity Detection SC-VBR Source Controlled - Variable Bit Rate SID Silence Insertion Descriptor S
30、WB Super Wideband VAD Voice Activity Detection WB Wideband WMOPS Weighted Millions of Operations Per Second 4 General The function of the Enhanced Voice Services coder VAD algorithm, or more accurately the SAD algorithm, is to indicate whether each 20 ms frame contains signals that should be transmi
31、tted, e.g. speech, music or other audio. The output of the SAD algorithm is a Boolean flag ( ) that is set to one for the active signal, which is any useful signal bearing some meaningful information. Otherwise, the flag is set to zero indicating an inactive signal, which has no meaningful informati
32、on. The inactive signal is mostly a pause or background noise. The procedure of the present document is mandatory for implementation in all network entities and User Equipment (UE)s supporting the EVS coder. The present document does not describe the ANSI-C code of this procedure. In the case of dis
33、crepancy between the procedure described in the present document and its ANSI-C code specifications contained in 4 the procedure defined by the 4 prevails. 5 The SAD Algorithm The Enhanced Voice Services codec signal activity detection (SAD) module described in the present document consists of three
34、 sub-SAD modules; SAD1, SAD2 and SAD3. SAD1 and SAD2 are combined initially to provide an efficient preliminary activity decision. This preliminary decision is then modified by the third sub-SAD module, SAD3, depending upon the codec mode of operation. The efficient preliminary activity output is us
35、ed as the final SAD decision for the AMR-WB IO modes, while the activity output with SAD3 is used as the final SAD decision for all other bit-rates. Sub-clause 5.1.12 in 3 describes the operation of the SAD and the algorithms involved in the three sub-SAD modules in detail. SADfETSI ETSI TS 126 451
36、V15.0.0 (2018-07)73GPP TS 26.451 version 15.0.0 Release 15Annex A (informative): Change history Change history Date TSG # TSG Doc. CR Rev Subject/Comment Old New 2014-09 65 SP-140466 Presented at TSG-SA #65 for approval 1.0.0 2014-09 65 Approved at TSG SA65 1.0.0 12.0.0 2015-12 70 Version for Releas
37、e 13 12.0.0 13.0.0 Change history Date Meeting TDoc CR Rev Cat Subject/Comment New version 2017-03 75 Version for Release 14 14.0.0 2018-06 80 Version for Release 15 15.0.0 ETSI ETSI TS 126 451 V15.0.0 (2018-07)83GPP TS 26.451 version 15.0.0 Release 15History Document history V15.0.0 July 2018 Publication
