ETSI TS 126 190-2018 Digital cellular telecommunications system (Phase 2+) (GSM) Universal Mobile Telecommunications System (UMTS) LTE Speech codec speech processing functions Adap_1.pdf

1、 ETSI TS 126 190 V15.0.0 (2018-07) Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); LTE; Speech codec speech processing functions; Adaptive Multi-Rate - Wideband (AMR-WB) speech codec; Transcoding functions (3GPP TS 26.190 version 15.0.0

2、 Release 15) TECHNICAL SPECIFICATION ETSI ETSI TS 126 190 V15.0.0 (2018-07)13GPP TS 26.190 version 15.0.0 Release 15Reference RTS/TSGS-0426190vf00 Keywords GSM,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

3、562 00017 - NAF 742 C Association but non lucratif enregistre 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

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9、GSM logo are trademarks registered and owned by the GSM Association. ETSI ETSI TS 126 190 V15.0.0 (2018-07)23GPP TS 26.190 version 15.0.0 Release 15Intellectual Property Rights Essential patents IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The inf

10、ormation pertaining to these essential IPRs, if any, is publicly available for ETSI members 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 th

11、e ETSI Secretariat. Latest updates are available on the ETSI Web server (https:/ipr.etsi.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 t

12、he updates on the ETSI Web server) which are, or may be, or may become, essential to the present document. Trademarks The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners. ETSI claims no ownership of these except for any which are indicat

13、ed as being the property of ETSI, and conveys no right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks. Foreword This Technical S

14、pecification (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 deliv

15、erables. 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 inter

16、preted 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 126 190 V15.0.0 (2018-07)33GPP TS 26.190 version 15.0.0 Release 15Contents Intell

17、ectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 5g31 Scope 6g32 Normative references . 6g33 Definitions, symbols and abbreviations . 6g33.1 Definitions 6g33.2 Symbols 7g33.3 Abbreviations . 11g34 Outline description . 12g34.1 Functional description of audio parts . 12g3

18、4.2 Preparation of speech samples 13g34.3 Principles of the adaptive multi-rate wideband speech encoder . 13g34.4 Principles of the adaptive multi-rate speech decoder . 16g34.5 Sequence and subjective importance of encoded parameters . 16g35 Functional description of the encoder 16g35.1 Pre-processi

19、ng 16g35.2 Linear prediction analysis and quantization . 17g35.2.1 Windowing and auto-correlation computation 17g35.2.2 Levinson-Durbin algorithm 17g35.2.3 LP to ISP conversion 18g35.2.4 ISP to LP conversion 19g35.2.5 Quantization of the ISP coefficients . 20g35.2.6 Interpolation of the ISPs . 21g35

20、.3 Perceptual weighting 21g35.4 Open-loop pitch analysis 22g35.4.1 6.60 kbit/s mode 22g35.4.2 8.85, 12.65, 14.25, 15.85, 18.25, 19.85, 23.05 and 23.85 kbit/s modes 23g35.5 Impulse response computation . 23g35.6 Target signal computation 24g35.7 Adaptive codebook . 24g35.8 Algebraic codebook 26g35.8.

21、1 Codebook structure . 26g35.8.1.1 23.85 and 23.05 kbit/s mode . 26g35.8.1.2 19.85 kbit/s mode 26g35.8.1.3 18.25 kbit/s mode 27g35.8.1.4 15.85 kbit/s mode 27g35.8.1.5 14.25 kbit/s mode 27g35.8.1.6 12.65 kbit/s mode 27g35.8.1.7 8.85 kbit/s mode 28g35.8.1.8 6.60 kbit/s mode 28g35.8.2 Pulse indexing .

22、28g35.8.3 Codebook search . 31g35.9 Quantization of the adaptive and fixed codebook gains . 34g35.10 Memory update 35g35.11 High-band gain generation . 36g36 Functional description of the decoder 36g36.1 Decoding and speech synthesis 36g36.2 High-pass filtering, up-scaling and interpolation . 39g36.

23、3 High frequency band 39g36.3.1 Generation of high-band excitation 39g36.3.2 LP filter for the high frequency band 40g3ETSI ETSI TS 126 190 V15.0.0 (2018-07)43GPP TS 26.190 version 15.0.0 Release 156.3.2.1 6.60 kbit/s mode 40g36.3.2.2 8.85, 12.65, 14.25, 15.85, 18.25, 19.85, 23.05 or 23.85 kbit/s mo

24、des . 40g36.3.3 High band synthesis 41g37 Detailed bit allocation of the adaptive multi-rate wideband codec 41g38 Homing sequences 46g38.1 Functional description 46g38.2 Definitions 47g38.3 Encoder homing . 47g38.4 Decoder homing . 47g39 Bibliography . 49g3Annex A (informative): Change history . 50g

25、3History 51g3ETSI ETSI TS 126 190 V15.0.0 (2018-07)53GPP TS 26.190 version 15.0.0 Release 15Foreword The present document describes the detailed mapping of the wideband telephony speech service employing the Adaptive Multi-Rate (AMR-WB) speech coder within the 3GPP system. The contents of the presen

26、t document are subject to continuing work within the TSG and may change following formal TSG approval. Should the TSG modify the contents of this TS, 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

27、first digit: 1 presented to TSG for information; 2 presented to TSG for approval; 3 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 edit

28、orial only changes have been incorporated in the specification; ETSI ETSI TS 126 190 V15.0.0 (2018-07)63GPP TS 26.190 version 15.0.0 Release 151 Scope This Telecommunication Standard (TS) describes the detailed mapping from input blocks of 320 speech samples in 16-bit uniform PCM format to encoded b

29、locks of 132, 177, 253, 285, 317, 365, 397, 461 and 477 bits and from encoded blocks of 132, 177, 253, 285, 317, 365, 397, 461 and 477 bits to output blocks of 320 reconstructed speech samples. The sampling rate is 16 000 samples/s leading to a bit rate for the encoded bit stream of 6.60, 8.85, 12.6

30、5, 14.25, 15.85, 18.25, 19.85, 23.05 or 23.85 kbit/s. The coding scheme for the multi-rate coding modes is the so-called Algebraic Code Excited Linear Prediction Coder, hereafter referred to as ACELP. The multi-rate wideband ACELP coder is referred to as MRWB-ACELP. 2 Normative references This TS in

31、corporates by dated and undated reference, provisions from other publications. These normative references are cited in the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this

32、TS only when incorporated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies. 1 GSM 03.50: “ Digital cellular telecommunications system (Phase 2); Transmission planning aspects of the speech service in the GSM Public Land Mobile Network

33、(PLMN) system“ 2 3GPP TS 26.201 : “AMR wideband speech codec; Frame structure“. 3 3GPP TS 26.194: “AMR wideband speech codec; Voice Activity Detection (VAD)“. 4 3GPP TS 26.173: “AMR wideband speech codec; ANSI-C code“. 5 3GPP TS 26.174: “AMR wideband speech codec; Test sequences“. 6 ITU-T Recommenda

34、tion G.711 (1988): “Coding of analogue signals by pulse code modulation Pulse code modulation (PCM) of voice frequencies“. 3 Definitions, symbols and abbreviations 3.1 Definitions For the purposes of this TS, the following definitions apply: adaptive codebook: The adaptive codebook contains excitati

35、on vectors that are adapted for every subframe. The adaptive codebook is derived from the long-term filter state. The lag value can be viewed as an index into the adaptive codebook. algebraic codebook: A fixed codebook where algebraic code is used to populate the excitation vectors (innovation vecto

36、rs). The excitation contains a small number of nonzero pulses with predefined interlaced sets of potential positions. The amplitudes and positions of the pulses of the kthexcitation codevector can be derived from its index k through a rule requiring no or minimal physical storage, in contrast with s

37、tochastic codebooks whereby the path from the index to the associated codevector involves look-up tables. anti-sparseness processing: An adaptive post-processing procedure applied to the fixed codebook vector in order to reduce perceptual artifacts from a sparse fixed codebook vector. closed-loop pi

38、tch analysis: This is the adaptive codebook search, i.e., a process of estimating the pitch (lag) value from the weighted input speech and the long term filter state. In the closed-loop search, the lag is searched using error minimization loop (analysis-by-synthesis). In the adaptive multi-rate wide

39、band codec, closed-loop pitch search is performed for every subframe. direct form coefficients: One of the formats for storing the short term filter parameters. In the adaptive multi-rate wideband codec, all filters which are used to modify speech samples use direct form coefficients. fixed codebook

40、: The fixed codebook contains excitation vectors for speech synthesis filters. The contents of the codebook are non-adaptive (i.e., fixed). In the adaptive multi-rate wideband codec, the fixed codebook is implemented using an algebraic codebook. ETSI ETSI TS 126 190 V15.0.0 (2018-07)73GPP TS 26.190

41、version 15.0.0 Release 15fractional lags: A set of lag values having sub-sample resolution. In the adaptive multi-rate wideband codec a sub-sample resolution of 1/4th or 1/2nd of a sample is used. frame: A time interval equal to 20 ms (320 samples at an 16 kHz sampling rate). Immittance Spectral Fre

42、quencies: (see Immittance Spectral Pair) Immittance Spectral Pair: Transformation of LPC parameters. Immittance Spectral Pairs are obtained by decomposing the inverse filter transfer function A(z) to a set of two transfer functions, one having even symmetry and the other having odd symmetry. The Imm

43、ittance Spectral Pairs (also called as Immittance Spectral Frequencies) are the roots of these polynomials on the z-unit circle. integer lags: A set of lag values having whole sample resolution. interpolating filter: An FIR filter used to produce an estimate of sub-sample resolution samples, given a

44、n input sampled with integer sample resolution. In this implementation, the interpolating filter has low pass filter characteristics. Thus the adaptive codebook consists of the low-pass filtered interpolated past excitation. inverse filter: This filter removes the short term correlation from the spe

45、ech signal. The filter models an inverse frequency response of the vocal tract. lag: The long term filter delay. This is typically the true pitch period, or its multiple or sub-multiple. LP analysis window: For each frame, the short term filter coefficients are computed using the high pass filtered

46、speech samples within the analysis window. In the adaptive multi-rate wideband codec, the length of the analysis window is always 384 samples. For all the modes, a single asymmetric window is used to generate a single set of LP coefficients. The 5 ms look-ahead is used in the analysis. LP coefficien

47、ts: Linear Prediction (LP) coefficients (also referred as Linear Predictive Coding (LPC) coefficients) is a generic descriptive term for the short term filter coefficients. mode: When used alone, refers to the source codec mode, i.e., to one of the source codecs employed in the AMR-WB codec. open-lo

48、op pitch search: A process of estimating the near optimal lag directly from the weighted speech input. This is done to simplify the pitch analysis and confine the closed-loop pitch search to a small number of lags around the open-loop estimated lags. In the adaptive multi-rate wideband codec, an ope

49、n-loop pitch search is performed in every other subframe. residual: The output signal resulting from an inverse filtering operation. short term synthesis filter: This filter introduces, into the excitation signal, short term correlation which models the impulse response of the vocal tract. perceptual weighting filter: This filter is employed in the analysis-by-synthesis search of the codebooks. The filter exploits the noise masking properties of the formants (vocal tract resonances) by weighting the error less in regions near the formant frequencies and more in reg