1、 ETSI TS 1Digital cellular telecoHHalf rat(3GPP TS 46.0TECHNICAL SPECIFICATION146 020 V13.0.0 (2016communications system (PhaHalf rate speech; rate speech transcoding .020 version 13.0.0 Release 13GLOBAL SYSTEMOBILE COMMUN16-01) hase 2+); 13) TEM FOR ICATIONSRETSI ETSI TS 146 020 V13.0.0 (2016-01)13
2、GPP TS 46.020 version 13.0.0 Release 13Reference RTS/TSGS-0446020vd00 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 enregistre la Sous-Prfecture de Gra
3、sse (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 document shall not be modified wi
4、thout 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 within ETSI Secretariat. Users of
5、 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 document, please send your comment t
6、o 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 authorized by written permission of ETSI. The co
7、ntent 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, UMTSTMand the ETSI logo are Trade
8、 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. ETSI ETSI TS 146 020 V13.0.0 (2016-01)
9、23GPP TS 46.020 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 i
10、n 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 Policy
11、, 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 Techni
12、cal 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 146 020 V13.0.0 (2016-01)33GPP TS 46.020 version 13.0.0 Release 13Contents I
15、ntellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 5g31 Scope 6g32 References 6g33 Definitions, symbols and abbreviations . 6g33.1 Definitions 6g33.2 Symbols 8g33.3 Abbreviations . 9g34 Functional description of the GSM half rate speech codec 9g34.1 GSM half rate spee
16、ch encoder 10g34.1.1 High-pass filter . 12g34.1.2 Segmentation 12g34.1.3 Fixed Point Lattice Technique (FLAT) 12g34.1.4 Spectral quantization. 14g34.1.4.1 Autocorrelation Fixed Point Lattice Technique (AFLAT) 14g34.1.5 Frame energy calculation and quantization 16g34.1.6 Soft interpolation of the spe
17、ctral parameters 16g34.1.7 Spectral noise weighting filter coefficients . 17g34.1.8 Long Term Predictor lag determination 18g34.1.8.1 Open loop long term search initialization . 19g34.1.8.2 Open loop lag search . 20g34.1.8.3 Frame lag trajectory search (Mode 0) 25g34.1.8.4 Voicing mode selection . 2
18、7g34.1.8.5 Closed loop lag search 27g34.1.9 Harmonic noise weighting 28g34.1.10 Code search algorithm 30g34.1.10.1 Decorrelation of filtered basis vectors. 31g34.1.10.2 Fast search technique 32g34.1.11 Multimode gain vector quantization . 33g34.1.11.1 Coding GS and P0 . 33g34.2 GSM half rate speech
19、decoder 36g34.2.1 Excitation generation 37g34.2.2 Adaptive pitch prefilter . 37g34.2.3 Synthesis Filter . 37g34.2.4 Adaptive spectral postfilter . 37g34.2.5 Updating decoder states 39g35 Homing sequences 39g35.1 Functional description 39g35.2 Definitions 39g35.3 Encoder homing . 40g35.4 Decoder homi
20、ng . 40g35.5 Encoder home state 40g35.6 Decoder home state 40g3Annex A (normative): Codec parameter description 41g3A.1 Codec parameter description 41g3A.1.1 MODE 41g3A.1.2 R0 . 41g3A.1.3 LPC1 - LPC3 42g3ETSI ETSI TS 146 020 V13.0.0 (2016-01)43GPP TS 46.020 version 13.0.0 Release 13A.1.4 LAG_1 - LAG
21、_4 42g3A.1.5 CODEx_1 - CODEx_4 . 42g3A.1.6 GSP0_1 - GSP0_4 42g3A.2 Basic coder parameters . 42g3Annex B (normative): Order of occurrence of the codec parameters over Abis 43g3Annex C (informative): Bibliography . 44g3Annex D (informative): Change history . 45g3History 46g3ETSI ETSI TS 146 020 V13.0.
22、0 (2016-01)53GPP TS 46.020 version 13.0.0 Release 13Foreword This Technical Specification has been produced by the 3rdGeneration Partnership Project (3GPP). The present document specifies the speech codec to be used for the GSM half rate channel for the digital cellular telecommunications system. Th
23、e present document is part of a series covering the half rate speech traffic channels 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
24、 rate speech; ANSI-C code for the GSM half rate speech codec“. GSM 06.07 “Digital cellular 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
25、transcoding“. GSM 06.21 “Digital cellular telecommunications system (Phase 2+); Half 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 spe
26、ech traffic channels“. GSM 06.41 “Digital cellular telecommunications system (Phase 2+); 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 ha
27、lf rate speech traffic channels“. 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
28、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 substance, i.e. technical
29、 enhancements, corrections, updates, etc. z the third digit is incremented when editorial only changes have been incorporated in the document. ETSI ETSI TS 146 020 V13.0.0 (2016-01)63GPP TS 46.020 version 13.0.0 Release 131 Scope The present document specifies the speech codec to be used for the GSM
30、 half rate channel. It also specifies the test methods to be used to verify that the codec implementation complies with the present document. The requirements are mandatory for the codec to be used either in GSM Mobile Stations (MS)s or Base Station Systems (BSS)s that utilize the half rate GSM spee
31、ch traffic channel. 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, edition number, version number, etc.) or non-specific. For a specific r
32、eference, 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 latest version of that document in the same Release as the present docume
33、nt. 1 GSM 06.02: “Digital cellular telecommunications system (Phase 2+); Half rate speech; Half rate speech processing functions“. 2 GSM 06.06: “Digital cellular telecommunications system (Phase 2+); Half rate speech; ANSI-C code for the GSM half rate speech codec“. 3 GSM 06.07: “Digital cellular te
34、lecommunications 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 definitions apply: adaptive codebook: adaptive codebook is derived from the long
35、term filter state. The lag value can be viewed as an index into the adaptive codebook. adaptive pitch prefilter: in the GSM half rate speech decoder, this filter is applied to the excitation signal to enhance the periodicity of the reconstructed speech. Note that this is done prior to the applicatio
36、n of the short term filter. adaptive spectral postfilter: in the GSM half rate speech decoder, this filter is applied to the output of the short term filter to enhance the perceptual quality of the reconstructed speech. allowable lags: set of lag values which may be coded by the GSM half rate speech
37、 encoder and transmitted to the GSM half rate speech decoder. This set contains both integer and fractional values (see table 3). analysis window: for each frame, the short term filter coefficients are computed using the high pass filtered speech samples within the analysis window. The analysis wind
38、ow is 170 samples in length, and is centered about the last 100 samples in the frame. basis vectors: set of M, M1, or M2 vectors of length Ns used to generate the VSELP codebook vectors. These vectors are not necessarily orthogonal. closed loop lag search: process of determining the near optimal lag
39、 value from the weighted input speech and the long term filter state. ETSI ETSI TS 146 020 V13.0.0 (2016-01)73GPP TS 46.020 version 13.0.0 Release 13closed loop lag trajectory: for a given frame, the sequence of near optimal lag values whose elements correspond to each of the four subframes as deter
40、mined by the closed loop lag search. codebook: set of vectors used in a vector quantizer. Codeword (OR Code): M, M1, or M2 bit symbol indicating the vector to be selected from a VSELP codebook. Delta (LAG) code: four bit code indicating the change in lag value for a subframe relative to the previous
41、 subframes coded lag. For frames in which the long term predictor is enabled (MODE 1, 2, or 3), the lag for subframe 1 is independently coded using eight bits, and delta codes are used for subframes 2, 3, and 4. direct form coefficients: one of the formats for storing the short term filter parameter
42、s. All filters which are used to modify speech samples use direct form coefficients. fractional lags: set of lag values having sub-sample resolution. Note that not every fractional lag value considered in the GSM half rate speech encoder is an allowable lag value. frame: time interval equal to 20 ms
43、, or 160 samples at an 8 kHz sampling rate. harmonic noise weighting filter: this filter exploits the noise masking properties of the spectral peaks which occur at harmonics of the pitch frequency by weighting the residual error less in regions near the pitch harmonics and more in regions away from
44、them. Note that this filter is only used when the long term filter is enabled (MODE = 1, 2 or 3). high pass filter: this filter is used to de-emphasize the low frequency components of the input speech signal. integer lags: set of lag values having whole sample resolution. interpolating filter: FIR f
45、ilter used to estimate sub-sample resolution samples, given an input sampled with integer sample resolution. lag: long term filter delay. This is typically the pitch period, or a multiple or sub-multiple of it. long term filter: this filter is used to generate the periodic component in the excitatio
46、n for the current subframe. This filter is only enabled for MODE = 1, 2 or 3. LPC coefficients: Linear Predictive Coding (LPC) coefficients is a generic descriptive term for describing the short term filter coefficients. open loop lag search: process of estimating the near optimal lag directly from
47、the weighted speech input. This is done to narrow the range of lag values over which the closed loop lag search shall be performed. open loop lag trajectory: for a given frame, the sequence of near optimal lag values whose elements correspond to the four subframes as determined by the open loop lag
48、search. reflection coefficients: alternative representation of the information contained in the short term filter parameters. residual: output signal resulting from an inverse filtering operation. short term filter: this filter introduces, into the excitation signal, short term correlation which mod
49、els the impulse response of the vocal tract. soft interpolation: process wherein a decision is made for each frame to use either interpolated or uninterpolated short term filter parameters for the four subframes in that frame. soft interpolation bit: one bit code indicating whether or not interpolation of the short term parameters is to be used in the current frame. spectral noise weighting filter: this filter exploits the noise masking properties of the formants (vocal tract resonances) by weighting the residual error less in regions near the formant frequenci
