1、 ETSI TS 126 171 V14.0.0 (2017-04) 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; General description (3GPP TS 26.171 version 14.0.0 R
2、elease 14) TECHNICAL SPECIFICATION ETSI ETSI TS 126 171 V14.0.0 (2017-04)13GPP TS 26.171 version 14.0.0 Release 14Reference RTS/TSGS-0426171ve00 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 56
3、2 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 a
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9、rade Marks registered and owned by the GSM Association. ETSI ETSI TS 126 171 V14.0.0 (2017-04)23GPP TS 26.171 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 esse
10、ntial 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 the ETSI Secretariat. Latest update
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12、) which are, or may be, or may become, essential to the present document. Foreword This Technical 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
13、 or GSM identities. These should be interpreted as being references to the corresponding ETSI 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“
14、, “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). “must“ and “must not“ are NOT allowed in ETSI deliverables except when used in direct citat
15、ion. ETSI ETSI TS 126 171 V14.0.0 (2017-04)33GPP TS 26.171 version 14.0.0 Release 14Contents Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 4g31 Scope 5g32 Normative references . 5g33 Definitions and abbreviations . 5g33.1 Abbreviations 5g34 General . 6g35 Adapti
16、ve Multi-Rate Wideband speech codec transcoding functions 8g36 Adaptive Multi-Rate Wideband speech codec ANSI C-code 8g37 Adaptive Multi-Rate Wideband speech codec test vectors 8g38 Adaptive Multi-Rate Wideband speech codec source controlled rate operation 9g39 Adaptive Multi-Rate Wideband speech co
17、dec voice activity detection . 9g310 Adaptive Multi-Rate Wideband speech codec comfort noise insertion . 10g311 Adaptive Multi-Rate Wideband speech codec error concealment of lost frames 10g312 Adaptive Multi-Rate Wideband speech codec frame structure 10g313 Adaptive Multi-Rate Wideband speech codec
18、 interface to RAN . 10g314 Adaptive Multi-Rate Wideband speech codec performance characterisation 11g3Annex A (informative): Change history . 12g3History 13g3ETSI ETSI TS 126 171 V14.0.0 (2017-04)43GPP TS 26.171 version 14.0.0 Release 14Foreword This Technical Specification has been produced by the
19、3GPP. The present document is an introduction to the speech processing parts of the wideband telephony speech service employing the Adaptive Multi-Rate Wideband (AMR-WB) speech coder within the 3GPP system. The contents of the present document are subject to continuing work within the TSG and may ch
20、ange 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 first digit: 1 presented to TSG for information; 2 presented to TSG
21、 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 editorial only changes have been incorporated in the specification; ETS
22、I ETSI TS 126 171 V14.0.0 (2017-04)53GPP TS 26.171 version 14.0.0 Release 141 Scope The present document is an introduction to the speech processing parts of the wideband telephony speech service employing the Adaptive Multi-Rate Wideband (AMR-WB) speech coder. A general overview of the speech proce
23、ssing functions is given, with reference to the documents where each function is specified in detail. 2 Normative references This TS incorporates by dated and undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the pub
24、lications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this 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 c
25、ellular telecommunications system (Phase 2); Transmission planning aspects of the speech service in the GSM Public Land Mobile Network (PLMN) system“. 2 3GPP TS 26.190 : “AMR Wideband Speech Codec; Transcoding functions“. 3 3GPP TS 26.173 : “AMR Wideband Speech Codec; ANSI-C code“. 4 3GPP TS 26.174
26、: “AMR Wideband Speech Codec; Test sequences“. 5 3GPP TS 26.193 : “AMR Wideband Speech Codec; Source Controlled Rate operation“. 6 3GPP TS 26.194 : “AMR Wideband Speech Codec; Voice Activity Detection (VAD)“. 7 3GPP TS 26.192 : “AMR Wideband Speech Codec; Comfort Noise Aspects“. 8 3GPP TS 26.191 : “
27、AMR Wideband Speech Codec; Error Concealment of Lost Frames. 9 3GPP TS 26.201 : “AMR Wideband Speech Codec; Frame Structure“. 10 3GPP TS 26.202 : “AMR Wideband Speech Codec; Interface to RAN“. 11 3GPP TR 26.976 : “Performance characterization of the Adaptive Multi-Rate Wideband (AMR-WB) speech codec
28、“. 3 Definitions and abbreviations 3.1 Abbreviations For the purposes of this TS, the following abbreviations apply: ACELP Algebraic Code Excited Linear Prediction AMR Adaptive Multi-Rate AMR-WB Adaptive Multi-Rate Wideband BFI Bad Frame Indication CHD Channel Decoder CHE Channel EncoderGSM Global S
29、ystem for Mobile communications ITU-T International Telecommunication Union Telecommunication standardisation sector (former CCITT) PCM Pulse Code Modulation PLMN Public Land Mobile Network PSTN Public Switched Telephone Network RX Receive SCR Source Controlled Rate SPD SPeech Decoder ETSI ETSI TS 1
30、26 171 V14.0.0 (2017-04)63GPP TS 26.171 version 14.0.0 Release 14SPE SPeech Encoder TC TranscoderTX Transmit UE User Equipment (terminal) 4 General The AMR-WB speech coder consists of the multi-rate speech coder, a source controlled rate scheme including a voice activity detector and a comfort noise
31、 generation system, and an error concealment mechanism to combat the effects of transmission errors and lost packets. The multi-rate speech coder is a single integrated speech codec with nine source rates from 6.60 kbit/s to 23.85 kbit/s, and a low rate background noise encoding mode. The speech cod
32、er is capable of switching its bit-rate every 20 ms speech frame upon command. A reference configuration where the various speech processing functions are identified is given in Figure 1. In this figure, the relevant specifications for each function are also indicated. In Figure 1, the audio parts i
33、ncluding analogue to digital and digital to analogue conversion are included, to show the complete speech path between the audio input/output in the User Equipment (UE) and the digital interface of the network. The detailed specification of the audio parts is not within the scope of this document. T
34、hese aspects are only considered to the extent that the performance of the audio parts affect the performance of the speech transcoder. ETSI ETSI TS 126 171 V14.0.0 (2017-04)73GPP TS 26.171 version 14.0.0 Release 14Figure 1: Overview of audio processing functions 1) 8-bit A-law or -law PCM (ITU-T re
35、commendation G.711), 8000 samples/s 2) 14-bit uniform PCM, 16 000 samples/s 3) Voice Activity Detector (VAD) flag 4) Encoded speech frame, 50 frames/s, number of bits/frame depending on the AMR-WB codec mode 5) Silence Descriptor (SID) frame. 6) TX_TYPE, 3 bits, indicates whether information bits ar
36、e available and if they are speech or SID information 7) Information bits delivered to the 3G AN 8) Information bits received from the 3G AN 9) RX_TYPE, the type of frame received quantized into three bits 10) Silence Descriptor (SID) flag 8bit / A-lawto14-bituniformLPF A/D12MS side onlyBSS side onl
37、y(narrowband speech)TS 26.190GSM 03.50TRANSMIT SIDESpeechEncoderComfortNoiseTXFunctionsVoiceActivityDetectorDTXControlandOperation364567SID frameSpeech frameVAD14-bituniformto8bit / A-lawLPFD/A18MS side onlyBSS side only (narrowband speech)GSM 03.50RECEIVE SIDESpeechDecoderSpeechframesubstitutionDTX
38、ControlandOperation45910SID frameSpeech frameComfortNoiseRXFunctions112SPflagInfo.bitsBFIInfo.bitsSIDTAFUpsampling1:2BSS side only (wideband speech)14-bituniform2TS 26.190TS 26.190TS 26.190TS 26.192TS 26.192TS 26.194214-bituniformBSS side only (wideband speech)Downsampling2:1TS 26.191TS 26.193TS 26.
39、193ETSI ETSI TS 126 171 V14.0.0 (2017-04)83GPP TS 26.171 version 14.0.0 Release 1411) Time Alignment Flag (TAF), marks the position of the SID frame within the SACCH multiframe 5 Adaptive Multi-Rate Wideband speech codec transcoding functions The adaptive multi-rate wideband speech codec is describe
40、d in 2. As shown in Figure 1, the speech encoder takes its input as a 14-bit uniform Pulse Code Modulated (PCM) signal either from the audio part of the UE or from the network side TBD or from the Public Switched Telephone Network (PSTN) via an narrowband 13-bit A-law or -law to wideband 14-bit unif
41、orm PCM conversion. An upsampling by factor of 2 has to be performed between narrowband and wideband speech signals. The encoded speech at the output of the speech encoder is packetized and delivered to the network interface. In the receive direction, the inverse operations take place. The detailed
42、mapping between input blocks of 320 speech samples in 14-bit uniform PCM format to encoded blocks (in which the number of bits depends on the presently used codec mode) and from these to output blocks of 320 reconstructed speech samples is described in 2. The coding scheme is Multi-Rate Algebraic Co
43、de Excited Linear Prediction. The bit-rates of the source codec are listed in Table 1. An AMR-WB speech codec capable UE shall support all source rates listed in Table 1. Table 1: Source codec bit-rates for the AMR-WB codec Codec mode Source codec bit-rate AMR-WB_23.85 23.85 kbit/sAMR-WB_23.05 23.05
44、 kbit/sAMR-WB_19.85 19.85 kbit/s AMR-WB_18.25 18.25 kbit/s AMR-WB_15.85 15.85 kbit/s AMR-WB_14.25 14.25 kbit/s AMR-WB_12.65 12.65 kbit/s AMR-WB_8.85 8.85 kbit/sAMR-WB_6.60 6.60 kbit/sAMR-WB_SID 1.75 kbit/s * (*) Assuming SID frames are continuously transmitted 6 Adaptive Multi-Rate Wideband speech c
45、odec ANSI C-code The ANSI C-code of the speech codec, VAD and CNG system are described in 3. The ANSI C-code is mandatory. 7 Adaptive Multi-Rate Wideband speech codec test vectors A set of digital test sequences is specified in 4, thus enabling the verification of compliance, i.e. bit-exactness, to
46、a high degree of confidence. The test sequences are defined separately for: - The speech codec described in 2, - The VAD described in 6, - The CN generation described in 7. ETSI ETSI TS 126 171 V14.0.0 (2017-04)93GPP TS 26.171 version 14.0.0 Release 14The adaptive multi-rate wideband speech transcod
47、er, VAD, SCR system and comfort noise parts of the audio processing functions (see Figure 1) are defined in bit exact arithmetic. Consequently, they shall react on a given input sequence always with the corresponding bit exact output sequence, provided that the internal state variables are also alwa
48、ys exactly in the same state at the beginning of the test. The input test sequences provided shall force the corresponding output test sequences, provided that the tested modules are in their home-state when starting. The modules may be set into their home states by provoking the appropriate homing-
49、functions. NOTE: This is normally done during reset (initialisation of the codec). Special inband signalling frames (encoder-homing-frame and decoder-homing-frame) described in 2 have been defined to provoke these homing-functions also in remotely placed modules. At the end of the first received homing frame, the audio functions that are defined in a bit exact way shall go into their predefined home states. The output corresponding to the first homing frame is dependent on the codec state when the frame was received. Any consecutive
