1、 ETSI TS 146 031 V14.0.0 (2017-04) Digital cellular telecommunications system (Phase 2+) (GSM); Full rate speech; Discontinuous Transmission (DTX) for full rate speech traffic channels (3GPP TS 46.031 version 14.0.0 Release 14) TECHNICAL SPECIFICATION GLOBAL SYSTEM FOR MOBILE COMMUNICATIONSRETSI ETS
2、I TS 146 031 V14.0.0 (2017-04)13GPP TS 46.031 version 14.0.0 Release 14Reference RTS/TSGS-0446031ve00 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 enr
3、egistre 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 any electronic and/or print versions of the present d
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9、on. ETSI ETSI TS 146 031 V14.0.0 (2017-04)23GPP TS 46.031 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 m
10、embers 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 updates are available on the ETSI Web server (https:/ipr.e
11、tsi.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 the updates on the ETSI Web server) which are, or may be, or may become, essential to
12、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 or GSM identities. These should be interpreted as b
13、eing 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“, “should“, “should not“, “may“, “need not“, “will“,
14、 “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 citation. ETSI ETSI TS 146 031 V14.0.0 (2017-04)33GPP TS
15、46.031 version 14.0.0 Release 14Contents Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 4g31 Scope 5g32 References 5g33 Definitions and abbreviations . 6g33.1 Definition of general terms . 6g33.2 Definition of terms on the receive side . 6g34 General . 6g34.1 Gen
16、eral organization 7g34.2 Naming convention 7g35 Transmit side 7g35.1 General operation . 7g35.1.1 Functions of the TX DTX handler 8g35.1.2 Functions of the TX radio subsystem . 9g36 Receive side 9g36.1 General operation . 10g36.1.1 Functions of the RX Radio Subsystem . 10g36.1.2 Functions of the RX
17、DTX handler 11g3Annex A (informative): Change history . 12g3History 13g3ETSI ETSI TS 146 031 V14.0.0 (2017-04)43GPP TS 46.031 version 14.0.0 Release 14Foreword This Technical Specification has been produced by the 3rdGeneration Partnership Project (3GPP). The contents of the present document are sub
18、ject 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 and an increase in version number as follows: Version x.y.z where: x the first
19、 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 enhancements, corrections, updates, etc. z the third digit is incremented whe
20、n editorial only changes have been incorporated in the document. ETSI ETSI TS 146 031 V14.0.0 (2017-04)53GPP TS 46.031 version 14.0.0 Release 141 Scope The present document gives a description of the general baseband operation of full rate speech traffic channels in the transmitter and in the receiv
21、er of GSM Mobile Stations (MS)s and Base Station Systems (BSS)s during Discontinuous Transmission (DTX). For clarity, the description is structured according the block diagrams in figures 1 and 4. Except in the case described next, this structure of distributing the various functions between system
22、entities is not mandatory for implementation, as long as the operation on the air interface and on the speech decoder output remains the same. In the case of BSSs where the speech transcoder is located remotely in the Base Station Controller (BSC), the implementation of the interfaces between the DT
23、X Handlers and the Radio Subsystem (RSS) as described in the present document together with all their flags is mandatory, being a part of the A-bis- interface as described in GSM 08.60. In this case the various flags also serve to avoid additional delays. The DTX functions described in the present d
24、ocument are mandatory for implementation in all GSM MSs. The receiver requirements are mandatory for implementation in all GSM BSSs, the transmitter requirements only for those where downlink DTX will be used. DTX shall be in operation in GSM MSs if commanded so by the network, see GSM 04.08. 2 Refe
25、rences 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 reference, subsequent revis
26、ions 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 document. 1 GSM 01.04: “Digital
27、cellular telecommunications system (Phase 2+); Abbreviations and acronyms“. 2 GSM 04.08: “Digital cellular telecommunications system (Phase 2+); Mobile radio interface layer 3 specification“. 3 GSM 05.03: “Digital cellular telecommunications system (Phase 2+); Channel coding“. 4 GSM 05.05: “Digital
28、cellular telecommunications system (Phase 2+); Radio transmission and reception“. 5 GSM 05.08: “Digital cellular telecommunications system (Phase 2+); Radio subsystem link control“. 6 GSM 06.01: “Digital cellular telecommunications system (Phase 2+); Full rate speech; Processing functions“. 7 GSM 06
29、.10: “Digital cellular telecommunications system (Phase 2+); Full rate speech; Transcoding“. 8 GSM 06.11: “Digital cellular telecommunications system (Phase 2+); Full rate speech; Substitution and muting of lost frames for full rate speech channels“. 9 GSM 06.12: “Digital cellular telecommunications
30、 system (Phase 2+); Full rate speech; Comfort noise aspect for full rate speech traffic channels“. ETSI ETSI TS 146 031 V14.0.0 (2017-04)63GPP TS 46.031 version 14.0.0 Release 1410 GSM 06.32: “Digital cellular telecommunications system (Phase 2+); Voice Activity Detector (VAD)“. 11 GSM 08.60: “Digit
31、al cellular telecommunications system (Phase 2+); Inband control of remote transcoders and rate adaptors for Enhanced Full Rate (EFR) and full rate traffic channels“. 3 Definitions and abbreviations Abbreviations used in the present document are listed in GSM 01.04. 3.1 Definition of general terms f
32、rame: time interval of 20 msec. corresponding to the time segmentation of the full rate speech transcoder (GSM 06.10), also used as a short term for a traffic frame. traffic frame: block of 260 information bits (see GSM 05.03) transmitted on the full rate speech traffic channel. (SID) silence descri
33、ptor frame: frame characterized by the SID code word. It conveys information on the acoustic background noise. SID code word: fixed bit pattern defined in GSM 06.12, for labelling a traffic frame as a SID frame. SID field: bit positions defined in GSM 06.12, of the SID codeword within a SID frame. s
34、peech frame: traffic frame that cannot be classified as a SID frame. 3.2 Definition of terms on the receive side bad traffic frame: traffic frame flagged BFI=1 (Bad Frame Indication) by the Radio Subsystem. good traffic frame: traffic frame flagged BFI=0 by the Radio Subsystem. good speech frame: go
35、od traffic frame which is not an accepted SID frame. accepted SID frame: traffic frame in which the SID field deviates in less than 16 bit positions from the SID code word (flag SID=2 or SID=1). valid SID frame: good traffic frame in which the SID field deviates in less than 2 bit positions from the
36、 SID code word (flag SID=2). This frame is valid for updating of comfort noise parameters at any time. invalid SID frame: accepted SID frame with BFI=1, or accepted SID frame with BFI=0, in which the SID field deviates in more than 1 bit position from the SID code word (flag SID=1). This frame is no
37、t valid for updating comfort noise parameters, but the frame conveys information that comfort noise generations should be started or continued. unusable frame: bad traffic frame that is not an accepted SID frame. lost SID frame: unusable frame received when the RX DTX Handler is generating comfort n
38、oise and a SID frame is expected (Time Alignment Flag, TAF=1). lost speech frame: unusable frame received when the RX DTX Handler is passing on traffic frames directly to the speech decoder. 4 General Discontinuous Transmission is a mechanism which allows the radio transmitter to be switched off mos
39、t of the time during speech pauses for the following two purposes: - to save power in the MS; - to reduce the overall interference level on the air. ETSI ETSI TS 146 031 V14.0.0 (2017-04)73GPP TS 46.031 version 14.0.0 Release 144.1 General organization The overall DTX mechanism described in the pres
40、ent document requires the following functions: - a Voice Activity Detector on the transmit side; - evaluation of the background acoustic noise on the transmit side, in order to transmit characteristic parameters to the receive side; - generation on the receive side of a similar noise, called comfort
41、 noise, during periods where the radio transmission is cut. The Voice Activity Detector is defined in GSM 06.32 “Voice Activity Detector“, the comfort noise functions in GSM 06.12 “Comfort Noise Aspects“. Both are based partly on the speech transcoder and its internal variables, defined in GSM 06.10
42、 “GSM Full Rate Speech Transcoding“. In addition to these functions, if the parameters arriving at the receive side are detected to be seriously corrupted by errors, the speech or comfort noise must be generated from substituted data in order to avoid seriously annoying effects for the listener. Thi
43、s function is defined in GSM 06.11 “Substitution and Muting of Lost Frames“. An overall description of the speech processing parts can be found in GSM 06.01 “Processing functions“. 4.2 Naming convention Clause 3 lists the definitions of terms relevant for the DTX functions, as used in this and the t
44、echnical specifications mentioned above. 5 Transmit side A block diagram of the transmit side DTX functions is shown in figure 1. TX DTX handlerTX radio subsystemSpeech encoderComfortNoiseComputationChannelencodingSP flagmonitoringVoice ActivityDetectionSP flag1Information bits260Figure 1: Block dia
45、gram of the transmit side DTX functions 5.1 General operation The TX DTX Handler continuously passes traffic frames, individually marked by a flag SP, to the Radio Subsystem. This binary flag is redundant to the SID code word labelling. SP=1 indicates a speech frame, SP=0 a SID frame. ETSI ETSI TS 1
46、46 031 V14.0.0 (2017-04)83GPP TS 46.031 version 14.0.0 Release 14The scheduling of the frames for transmission on the air interface is controlled by the radio subsystem alone, on the basis of the SP flag as described next. 5.1.1 Functions of the TX DTX handler To allow an exact verification of the T
47、X DTX handler functions, all frames before the reset of the system have to be treated as if there would have been speech frames for an infinitely long time. Therefore, the first N frames after the reset are always marked with SP=1, even if VAD=0 (hangover period, see below). The Voice Activity Detec
48、tor must be operating all the time in order to assess whether the input signal contains speech or not. The output is a binary flag (VAD=1 or VAD=0, respectively) on a frame by frame basis (see GSM 06.32). The VAD flag controls indirectly, via the TX DTX Handler operations described below, the overal
49、l DTX operation on the transmit side. Whenever VAD=1, the speech encoder output frame shall be passed directly to the radio subsystem, marked with SP=1. At the end of a speech burst (transition VAD=1 to VAD=0), it takes N+1 consecutive frames to make a new updated SID frame available (see GSM 06.12). Normally, the first N speech encoder output frames after the end of the speech burst shall therefore be passed directly to the radio subsystem, marked with SP=1 (“hangover period“). The first new SID frame is then passed to the RSS as frame N+1 after t
