1、 ETSI TS 126 450 V14.0.0 (2017-04) Universal Mobile Telecommunications System (UMTS); LTE; Codec for Enhanced Voice Services (EVS); Discontinuous Transmission (DTX) (3GPP TS 26.450 version 14.0.0 Release 14) TECHNICAL SPECIFICATION ETSI ETSI TS 126 450 V14.0.0 (2017-04)13GPP TS 26.450 version 14.0.0
2、 Release 14Reference RTS/TSGS-0426450ve00 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 Impo
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9、50 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 non-members, and can be found in ETSI SR 000
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12、tion (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 references to the corresponding ETSI deliverables.
13、 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“, “can“ and “cannot“ are to be interpreted a
14、s 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 126 450 V14.0.0 (2017-04)33GPP TS 26.450 version 14.0.0 Release 14Contents Intellectual P
15、roperty Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 4g31 Scope 5g32 References 5g33 Abbreviations . 5g34 General . 6g34.1 Background 6g34.2 General organization 6g35 EVS Codec DTX Operation . 7g35.1 Transmit (TX) side . 7g35.2 Receive (RX) side 7g3Annex A (informative): Change hist
16、ory . 8g3History 9g3ETSI ETSI TS 126 450 V14.0.0 (2017-04)43GPP TS 26.450 version 14.0.0 Release 14Foreword This Technical Specification has been produced by the 3rdGeneration Partnership Project (3GPP). The contents of the present document are subject to continuing work within the TSG and may chang
17、e 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; 2 presen
18、ted 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 incorporated in t
19、he document. ETSI ETSI TS 126 450 V14.0.0 (2017-04)53GPP TS 26.450 version 14.0.0 Release 141 Scope This document specifies the system level aspects of the Discontinuous Transmission (DTX) function of the EVS codec. 2 References The following documents contain provisions which, through reference in
20、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 apply. - For a non-specific reference, the latest version appl
21、ies. 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 3GPP TR 21.905: “Vocabulary for 3GPP Specifications“. 2 3GPP TS 26.445: “Codec for Enhanced
22、Voice Services (EVS); Detailed Algorithmic Description “. 3 3GPP TS 26.442: “ Codec for Enhanced Voice Services (EVS); ANSI C code (fixed-point)“. 4 3GPP TS 26.443: “ Codec for Enhanced Voice Services (EVS); ANSI C code (floating-point)“. 5 3GPP TS 26.444: “ Codec for Enhanced Voice Services (EVS);
23、Test Sequences“. 6 3GPP TS 26.446: “ Codec for Enhanced Voice Services (EVS); AMR-WB Backward Compatible Functions“. 7 3GPP TS 26.447: “ Codec for Enhanced Voice Services (EVS); Error Concealment of Lost Packets“. 8 3GPP TS 26.448: “ Codec for Enhanced Voice Services (EVS); Jitter Buffer Management“
24、. 9 3GPP TS 26.449: “ Codec for Enhanced Voice Services (EVS); Comfort Noise Generation (CNG) Aspects“. 10 3GPP TS 26.441: “ Codec for Enhanced Voice Services (EVS); General Overview“. 11 3GPP TS 26.451: “ Codec for Enhanced Voice Services (EVS); Voice Activity Detection (VAD)“. 12 3GPP TS 26.114: “
25、Multimedia Telephony; Media handling and interaction“. 13 3GPP TS 26.131: “Terminal acoustic characteristics for telephony; Requirements “. 14 3GPP TR 26.952: “Codec for Enhanced Voice Services (EVS); Performance Characterization”. 3 Abbreviations For the purposes of the present document, the abbrev
26、iations 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 1. ACELP Algebraic Code-Excited Linear Prediction AMR-WB Adaptive Multi Rate Wideband (codec) CNG Comfort Noise Ge
27、nerator ETSI ETSI TS 126 450 V14.0.0 (2017-04)63GPP TS 26.450 version 14.0.0 Release 14DTX Discontinuous Transmission EVS Enhanced Voice Services FB Fullband FEC Frame Erasure Concealment IP Internet Protocol JBM Jitter Buffer Management MSB Most Significant Bit MTSI Multimedia Telephony Service for
28、 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 SWB Super Wideband VAD Voice Activity Detection WB Wideband WMOPS Weighted Millions of Operations Per Second 4 Gener
29、al 4.1 Background The present document specifies the system level aspects of the Discontinuous Transmission (DTX) function of the EVS codec. Specific codec functions that implement the DTX functionality are described in TS 26.445 2. Discontinuous transmission (DTX) is a mechanism for the EVS Codec t
30、o encode the input signal at a lower average rate by taking speech inactivity into account. The DTX scheme is useful for the following purposes: - to conserve UE power, - to improve network capacity. DTX in the transmitting path (uplink) shall be in operation in UEs if commanded so by the network. T
31、he UE shall handle DTX in the receiving path (downlink) at any time, regardless of whether DTX in the transmitting path is commanded or not. 4.2 General organization The default DTX mechanism described in the present document requires the following functions: - a Signal Activity Detector (SAD) on th
32、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 transmission is switched off
33、. The Signal Activity Detector (SAD) is defined in TS 26.451 11 and the comfort noise functions in TS 26.449 9. Both are based partly on the EVS Codec and its internal variables defined in TS 26.445 2. In addition to these functions, if the parameters arriving at the RX side are detected to be serio
34、usly corrupted by errors, the speech or comfort noise shall be generated from substituted data in order to avoid seriously annoying effects for the listener. These functions are defined in TS 26.447 7. An overall description of the speech processing parts can be found in TS 26.441 10. An overview of
35、 the DTX operation is shown in Figure 1. ETSI ETSI TS 126 450 V14.0.0 (2017-04)73GPP TS 26.450 version 14.0.0 Release 14Figure 1: Block diagram of DTX Operation 5 EVS Codec DTX Operation 5.1 Transmit (TX) side There are two algorithms for extending the DTX hangover period. One is a general hangover
36、algorithm and other is specific to music. Both are defined in clause 5.1.12.5 of TS 26.445 2. The main specification of the DTX/CNG algorithms is contained in clause 5.6 of TS 26.445 2. The bit allocation of SID frames generated for DTX operation is defined in clause 7.2 of TS 26.445 2. 5.2 Receive
37、(RX) side Operation of the EVS decoder, including decoding of SID frames generated during DTX operation is described in clause 6.7 of TS 26.445 2. ETSI ETSI TS 126 450 V14.0.0 (2017-04)83GPP TS 26.450 version 14.0.0 Release 14Annex A (informative): Change history Change history Date TSG # TSG Doc. C
38、R Rev Subject/Comment Old New 2014-09 65 SP-140465 Presented at TSG#65 for approval 1.0.0 2014-09 65 Approved at TSG SA#65 1.0.0 12.0.0 2015-12 70 Version for Release 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 ETSI ETSI TS 126 450 V14.0.0 (2017-04)93GPP TS 26.450 version 14.0.0 Release 14History Document history V14.0.0 April 2017 Publication
