1、 ETSI TS 146 002 V14.0.0 (2017-04) Digital cellular telecommunications system (Phase 2+) (GSM); Half rate speech; Half rate speech processing functions (3GPP TS 46.002 version 14.0.0 Release 14) TECHNICAL SPECIFICATION GLOBAL SYSTEM FOR MOBILE COMMUNICATIONSRETSI ETSI TS 146 002 V14.0.0 (2017-04)13G
2、PP TS 46.002 version 14.0.0 Release 14Reference RTS/TSGS-0446002ve00 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 Gras
3、se (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 wit
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8、are Trade 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 146 002 V14.0.0
9、(2017-04)23GPP TS 46.002 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 b
10、e 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 updates are available on the ETSI Web server (https:/ipr.etsi.org/). Pursuant to the ETSI I
11、PR 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 the updates on the ETSI Web server) which are, or may be, or may become, essential to the present document. Foreword Th
12、is 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 or GSM identities. These should be interpreted as being references to the correspond
13、ing 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“, “should“, “should not“, “may“, “need not“, “will“, “will not“, “can“ and “cannot“ a
14、re 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 citation. ETSI ETSI TS 146 002 V14.0.0 (2017-04)33GPP TS 46.002 version 14.0.0 Release 14C
15、ontents Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 4g31 Scope 5g32 References 5g33 Definitions and abbreviations . 5g33.1 Definitions 5g33.2 Abbreviations . 6g34 General . 6g35 Half rate speech transcoding 8g36 Half rate Discontinuous Transmission (DTX) . 8g3
16、7 Half rate Voice Activity Detection (VAD) 9g38 Half rate comfort noise insertion 9g39 Half rate lost speech frame substitution and muting 9g310 Half rate codec homing 10g3Annex A (informative): Change History 11g3History 12g3ETSI ETSI TS 146 002 V14.0.0 (2017-04)43GPP TS 46.002 version 14.0.0 Relea
17、se 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 change following formal TSG approval. Should the TSG modify the contents of the present document, i
18、t 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 for approval; 3 or greater indicates TSG approved document under change control. y
19、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 document. The present document gives a general overview of the half rate speech traffic cha
20、nnels speech processing functions for the digital cellular telecommunications system. The present document is part of ENs 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 pro
21、cessing functions“. GSM 06.20 “Digital cellular telecommunications system (Phase 2+); Half rate speech; Half rate speech 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“. GS
22、M 06.22 “Digital cellular telecommunications system (Phase 2+); Half rate speech; Comfort noise aspects for half rate speech traffic channels“. GSM 06.41 “Digital cellular telecommunications system (Phase 2+); Half rate speech; Discontinuous Transmission (DTX) for half rate speech traffic channels“.
23、 GSM 06.42 “Digital cellular telecommunications system (Phase 2+); Half rate speech; Voice Activity Detector (VAD) for half rate speech traffic channels“. GSM 06.06 “Digital cellular telecommunications system (Phase 2+); Half rate speech; ANSI-C code for the GSM half rate speech codec“. GSM 06.07 “D
24、igital cellular telecommunications system (Phase 2+); Half rate speech; Test sequences for the GSM half rate speech codec“. ETSI ETSI TS 146 002 V14.0.0 (2017-04)53GPP TS 46.002 version 14.0.0 Release 141 Scope The present document is an introduction to GSM 06.20 4, GSM 06.21 5, GSM 06.22 6, GSM 06.
25、41 7 and GSM 06.42 8 TSs dealing with the speech processing functions in the half-rate channel of the GSM system. A general overview of the speech processing functions is given, with reference to the TSs where each function is specified in detail. 2 References The following documents contain provisi
26、ons 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 reference, subsequent revisions do not apply. For a non-specific referenc
27、e, 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 document. 1 GSM 01.04: “Digital cellular telecommunication system (Phase 2+);
28、Abbreviations and acronyms“. 2 GSM 03.50: “Digital cellular telecommunication system (Phase 2+); Transmission planning aspects of the speech services in the GSM Public Land Mobile Network (PLMN) system“. 3 GSM 05.03: “Digital cellular telecommunications system (Phase 2+); Channel coding“. 4 GSM 06.2
29、0: “Digital cellular telecommunications system (Phase 2+); Half rate speech: Half rate speech transcoding“. 5 GSM 06.21: “ Digital cellular telecommunications system (Phase 2+); Half rate speech; Substitution and muting of lost frame for half rate speech traffic channels“. 6 GSM 06.22: “Digital cell
30、ular telecommunications system (Phase 2+); Half rate speech; Comfort noise aspects for half rate speech traffic channels “. 7 GSM 06.41: “Digital cellular telecommunications system (Phase 2+); Half rate speech; Discontinuous transmission (DTX) for half rate speech traffic channels“. 8 GSM 06.42: “Di
31、gital cellular telecommunications system (Phase 2+); Half rate speech; Voice Activity Detector (VAD) for half rate speech traffic channels “. 9 ITU-T Recommendation G.711: “Pulse Code Modulation (PCM) of voice frequencies“. 10 GSM 06.07: “Digital cellular telecommunications system (Phase 2+); Half r
32、ate speech; Test sequences for the GSM half rate speech codec“. 11 GSM 06.06: “Digital cellular telecommunications system (Phase 2+); Half rate speech; ANSI-C code for the GSM half rate speech codec“. 3 Definitions and abbreviations 3.1 Definitions Definition of terms used in the present document ca
33、n be found in GSM 06.20 4, GSM 06.21 5, GSM 06.22 6, GSM 06.41 7 and GSM 06.42 8. ETSI ETSI TS 146 002 V14.0.0 (2017-04)63GPP TS 46.002 version 14.0.0 Release 143.2 Abbreviations For the purposes of the present document, the following abbreviations apply. BFI Bad Frame Indication BSS Base Station Sy
34、stem DTX Discontinuous Transmission GSM Global System for Mobile communications MS Mobile StationPCM Pulse Code Modulated PLMN Public Land Mobile Network PSTN Public Switched Telephone Network RF Radio Frequency RX Receive RSS Radio SubSystem SACCH Slow Associated Control CHannel SID SIlence Descrip
35、tor SP flag SPeech flag TAF Time Alignment Flag TX TransmitVSELP Vector Sum Excited Linear Predictor UFI Unreliable Frame Indication For abbreviations not given in this subclause, see GSM 01.04 1. 4 General Figure 1 presents a reference configuration where the various speech processing functions are
36、 identified. In this figure, the relevant documents for each function are also indicated. In figure 1, the audio parts including analogue to digital and digital to analogue conversion are included, to show the complete speech path between the audio input/output in the Mobile Station (MS) and the dig
37、ital interface of the Public Switched Telephone Network (PSTN). The detailed specification of the audio parts are contained in GSM 03.50 2. These aspects are only considered to the extent that the performance of the audio parts affect the performance of the speech transcoder. ETSI ETSI TS 146 002 V1
38、4.0.0 (2017-04)73GPP TS 46.002 version 14.0.0 Release 14BSS side only GSM 06.02MS side only GSM 03.5018 bit / A - law to 13 bit uniform267SPflaginfo.bitsTRANSMIT SIDESpeechencoder345GSM 06.42VADGSM 06.20Speech frameSID frameGSM 06.22GSM 06.41TX DTX handler6BSS side only GSM 06.02MS side only GSM 03.
39、5013 bit uniformto8 bit/A-lawRECEIVE SIDE245Speech frameSID frameGSM 06.41RX DTX handler89101112InfobitsBFISIDTAFUFIGSM 06.21GSM 06.20GSM 06.22Comfort noiseRX functionsSpeechframesubstitutionspeechdecoder1VoiceActivityDetectorA/DLPFComfort noiseTX functionsDTX controland operationDTX controland oper
40、ationD/A LPF1 8 bit /A-law or -law (PCS 1900) PCM (ITU-T Recommendation G.711) 9, 8 000 samples/s. 2 13 bit uniform PCM, 8 000 samples/s. 3 Voice Activity Detector (VAD) flag. 4 Encoded speech frame, 50 frames/s, 112 bits/frame. 5 SIlence Descriptor (SID) frame, 112 bits/frame. 6 SPeech (SP) flag, i
41、ndicates whether information bits are speech or SID information. 7 Information bits delivered to the radio subsystem. 8 Information bits received from the radio subsystem. 9 Bad Frame Indication (BFl) flag. 10 SIlence Descriptor (SID) flag. 11 Time Alignment Flag (TAF), marks the position of the SID
42、 frame within the Slow Associated Control CHannel (SACCH) multiframe. 12 Unreliable Frame Indication (UFI). Figure 1: Overview of audio processing functions ETSI ETSI TS 146 002 V14.0.0 (2017-04)83GPP TS 46.002 version 14.0.0 Release 145 Half rate speech transcoding The half rate speech transcoding
43、function is described in GSM 06.20 4. As shown in figure 1, the speech encoder takes its input as a 13 bit uniform Pulse Code Modulated (PCM) signal either from the audio part of the MS or on the network side, from the PSTN via an 8 bit/A-law or -law (PCS 1900) to 13 bit uniform PCM conversion. The
44、encoded speech at the output of the speech encoder is delivered to the channel coding function as defined in GSM 05.03 3 to produce an encoded block consisting of 228 bits leading to a gross bit rate of 11,4 kbit/s. In the RX direction, the inverse operations take place. GSM 06.20 4 describes the de
45、tailed mapping between input blocks of 160 speech samples in 13 bit uniform PCM format into encoded blocks of 112 bits and from encoded blocks of 112 bits to output blocks of 160 reconstructed speech samples. The sampling rate is 8 000 sample/s leading to an average bit rate for the encoded bit stre
46、am of 5,6 kbit/s. The coding scheme is called Vector Sum Excited Linear Prediction (VSELP) coding. GSM 06.20 4 describes the codec and GSM 06.06 11 defines the C code, thus enabling the verification of compliance to GSM 06.20 4 to a high degree of confidence by use of a set of digital test sequences
47、 given in GSM 06.07 10. 6 Half rate Discontinuous Transmission (DTX) The half rate discontinuous transmission function is described in GSM 06.41 7. During a normal conversation, the participants alternate so that, on the average, each direction of transmission is occupied about 50 % of the time. Dis
48、continuous Transmission (DTX) is a mode of operation where the transmitters are switched on only for those frames which contain useful information. This may be done for the following two purposes: 1) in the MS, battery life will be prolonged or a smaller battery could be used for a given operational
49、 duration; 2) the average interference level over the air interface is reduced, leading to better Radio Frequency (RF) spectrum efficiency. The overall DTX mechanism is implemented in the DTX handlers (Transmit (TX) and Receive (RX) described in GSM 06.41 7 and requires the following functions: - a Voice Activity Detector (VAD) on the TX side, see GSM 06.42 8; - evaluation of the background acoustic noise on the TX side, in order to transmit characteristic parameters to the RX side, see GSM 06.22 6
