1、 ETSI TS 1Universal Mobile TelCodec for EnhComfort Nois(3GPP TS 26.4TECHNICAL SPECIFICATION126 449 V13.0.0 (2016elecommunications System (LTE; n anced Voice Services (EVS)ise Generation (CNG) aspects.449 version 13.0.0 Release 1316-01) (UMTS); S); cts 13) ETSI ETSI TS 126 449 V13.0.0 (2016-01)13GPP
2、TS 26.449 version 13.0.0 Release 13Reference RTS/TSGS-0426449vd00 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 Gr
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9、)23GPP TS 26.449 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 non-members, and can be found
10、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/). Pursuant to the ETSI IPR Polic
11、y, 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 document. Foreword This Techn
12、ical 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 references to the corresponding ETSI
13、 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“, “can“ and “cannot“ are to be
14、 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 126 449 V13.0.0 (2016-01)33GPP TS 26.449 version 13.0.0 Release 13Contents
15、Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 4g31 Scope 5g32 References 5g33 Abbreviations . 5g34 General . 5g35 Functions on the transmit (TX) side . 6g35.1 EVS primary CNG operation . 6g35.2 EVS AMR-WB IO CNG operation 6g36 Functions on the receive (RX) side
16、7g36.1 EVS primary CNG operation . 7g36.2 EVS AMR-WB IO CNG operation 7g37 Computational details and bit allocation 7g3Annex A (informative): Change history . 8g3History 9g3ETSI ETSI TS 126 449 V13.0.0 (2016-01)43GPP TS 26.449 version 13.0.0 Release 13Foreword This Technical Specification has been p
17、roduced by the 3rdGeneration Partnership 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
18、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 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 su
19、bstance, i.e. technical enhancements, corrections, updates, etc. z the third digit is incremented when editorial only changes have been incorporated in the document. ETSI ETSI TS 126 449 V13.0.0 (2016-01)53GPP TS 26.449 version 13.0.0 Release 131 Scope The present document gives an overview for the
20、requirements of the background acoustic noise evaluation, noise parameter encoding/decoding and comfort noise generation for the Enhanced Voice Services (EVS) speech codec during Discontinuous Transmission (DTX) operation. 2 References The following documents contain provisions which, through refere
21、nce 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 apply. - For a non-specific reference, the latest versi
22、on 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 3GPP TR 21.905: “Vocabulary for 3GPP Specifications“. 2 3GPP TS 26.445: “Codec for En
23、hanced Voice Services (EVS); Codec Detailed Algorithmic Description“. 3 3GPP TS 26.442: “Codec for Enhanced Voice Services (EVS); EVS Codec ANSI C code (fixed-point)“. 4 3GPP TS 26.443: “Codec for Enhanced Voice Services (EVS); EVS Codec ANSI C code (floating-point)“. 3 Abbreviations For the purpose
24、s 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 1. CNG Comfort Noise Generation EVS Enhanced Voice Services FD-CNG Frequency
25、Domain based CNG LP-CNG Linear Prediction based CNG SID Silence Insertion Descriptor 4 General The present document gives an overview for the requirements of the background acoustic noise evaluation, noise parameter encoding/decoding and comfort noise generation for the Enhanced Voice Services (EVS)
26、 speech codec during Discontinuous Transmission (DTX) operation. The present document is mandatory for implementation in all network entities and UEs supporting the EVS codec. In the case of discrepancy between the EVS comfort noise aspects described in the present document and its ANSI-C code speci
27、fication contained in 3, the procedure defined by 3 prevails. In the case of discrepancy between the procedure described in the present document and its ANSI-C code specification contained in 4, the procedure defined by 4 prevails. A basic problem when using DTX is that the background acoustic noise
28、, which is transmitted together with the speech, would disappear when the transmission is cut, resulting in discontinuities of the background noise. Since the DTX 3GPP TS 26.449 version 13.0.0 Release 13switching can take place rapidly, it has been fcar environment with high background noise The pre
29、sent document specifies the way to ovnoise similar to the transmit (TX) side backgrand transmitted to the RX side at a regular ratchanges of the noise on the TX side. The Enhanced Voice Services (EVS) speech cprediction based CNG (LP-CNG) as well as athe two schemes is performed within the transthe
30、comfort noise are packed as a Silence InseThe update rate of the SID payload can be conadaptively modified according to the backgroframes while in the adaptive rate mode the upAs the functions of the CNG processing are hparameters, The present document only provialgorithmic descriptions are provided
31、 in the fo5 Functions on the5.1 EVS primary CNGThe CNG operation on the transmit side is deupdate is required. If the SID payload should encoder depending on the signal characteristicgeneration parameter and creates the related SFigure 1: TransmIn 2, all TX functions are described in claus- SID Upda
32、te mechanism can be found i- CNG Selector can be found in sub-clau- LP-CNG encoder in sub-clause 5.6.2 - FD-CNG encoder in sub-clause 5.6.3.5.2 EVS AMR-WB IO The update rate is basically fixed to an updatethe third frame after active speech are coded bETSI ETSI TS 126 4496n found that this effect ca
33、n be very annoying for the listene levels. In bad cases, the speech may be hardly intelligibovercome this problem by generating on the receive (RX)ound noise. The comfort noise parameters are estimatedrate when speech is not present. This allows the comfort nh codec supports two Comfort Noise Genera
34、tion (CNG) ss a frequency domain based scheme (FD-CNG). The selecansmit side functions on an input signal bases. The parameertion Descriptor (SID) payload. configured to a fixed number or to a mode where the updaround noise. The fixed rate mode is limited to updates betupdates are limited to 8 and 5
35、0 depending on the noise bee highly integrated into the speech codec and make use of v des an overview of the functions. The relevant referencee f llowing. the transmit (TX) side G operation described in figure 1. In DTX operation, the SID updater dbe updated, the CNG Selector enables either the LP
36、or tstic of the background noise. The selected CNG encoder cd SID payload. mit side Comfort Noise Generator functions u e 5.6. The algorithmic description of the n sub-clause 5.6.1.1 and 5.6.1.2 l use 5.6.1.3 IO CNG operation ate every 8thframe. However, when switching into DTX md by a SID frame. 4
37、V13.0.0 (2016-01)ener - especially in a gi le. X) side synthetic ted on the TX side oise to adapt to the schemes, a linear lection of the one of ters for generating date rate is between 1 and 100 behaviour. of other coding nces to the er decides if any SID or the FD CNG r calculates the noise mode,
38、the first and 3GPP TS 26.449 version 13.0.0 Release 13The CNG in the EVS AMR-WB interoperablTX description of the EVS AMR-WB IO mod6 Functions on the6.1 EVS primary CNGThe CNG operation on the receiver side is depmodule. The remaining bits contain the informFigure 2: ReceiveThe RX CNG operation is d
39、escribed in clausesynthesis of FD-CNG is described in clause 66.2 EVS AMR-WB IO The CNG in the EVS AMR-WB interoperablWB compatible CN parameters. The complete2, clause 6.8.4. 7 Computational dA computational description of comfort noise3 for the fix point implementation and in 4For the EVS primary
40、modes, the SID payloadscheme, where 0 stands for the LP-CNG and For the EVS AMR-WB IO modes, the SID paETSI ETSI TS 126 4497ble modes is based the LP-CNG coding scheme only. Theode can be found in 2, clause 5.7.12. the receive (RX) side G operation depicted in Figure 2. The first bit of the SID payl
41、oad deteror ation of the noise generator parameters to render the siiv side Comfort Noise Generator functions use 6.7. The synthesis of the LP-CNG is described in sub-6.7.3 in 2. IO CNG operation ble modes use only the LP-CNG decoding scheme for renlete CNG RX description of the EVS AMR-WB IO mode l
42、 details and bit allocation ise encoding and generation in form of an ANSI-C source 4 for the floating point implementation. ad consists of 48 bits. The first bit of the payload determind 1 for the FD-CNG. yload consists of 35 bits. 4 V13.0.0 (2016-01)he complete CNG termines the CNG e signal. claus
43、e 6.7.2 and the rendering the AMR-de can be found in ce code is given in mi es the CNG ETSI ETSI TS 126 449 V13.0.0 (2016-01)83GPP TS 26.449 version 13.0.0 Release 13Annex A (informative): Change history Change history Date TSG # TSG Doc. CR Rev Subject/Comment Old New 2014-09 65 SP-140464 Presented at TSG SA#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 ETSI ETSI TS 126 449 V13.0.0 (2016-01)93GPP TS 26.449 version 13.0.0 Release 13History Document history V13.0.0 January 2016 Publication
