1、 ETSI TS 146 001 V14.0.0 (2017-04) Digital cellular telecommunications system (Phase 2+) (GSM); Full rate speech; Processing functions (3GPP TS 46.001 version 14.0.0 Release 14) TECHNICAL SPECIFICATION GLOBAL SYSTEM FOR MOBILE COMMUNICATIONSRETSI ETSI TS 146 001 V14.0.0 (2017-04)13GPP TS 46.001 vers
2、ion 14.0.0 Release 14Reference RTS/TSGS-0446001ve00 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 Grasse (06) N 7803/88
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9、 46.001 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 be found in ETSI S
10、R 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, no inv
11、estigation, 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 Technical Spec
12、ification (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 delivera
13、bles. 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 interpre
14、ted 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 146 001 V14.0.0 (2017-04)33GPP TS 46.001 version 14.0.0 Release 14Contents Intellect
15、ual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 4g31 Scope 5g32 References 5g33 Abbreviations . 5g34 Introduction 6g35 Full rate speech transcoding (GSM 06.10) . 6g36 Full rate Discontinuous Transmission (DTX) (GSM 06.31) 6g37 Full rate Voice Activity Detection (VAD) (GSM
16、06.32) . 7g38 Full rate comfort noise insertion (GSM 06.12) 7g39 Full rate lost speech frame substitution and muting (GSM 06.11) . 7g310 Full Rate codec homing (GSM 06.10, optional feature) 7g311 Speech transmission functions of the half rate traffic channel . 8g3Annex A (informative): Change Histor
17、y 10g3History 11g3ETSI ETSI TS 146 001 V14.0.0 (2017-04)43GPP TS 46.001 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 subject to continuing work within the TSG and may change
18、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 digit: 1 presented to TSG for information; 2 presente
19、d 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 when editorial only changes have been incorporated in the
20、 document. ETSI ETSI TS 146 001 V14.0.0 (2017-04)53GPP TS 46.001 version 14.0.0 Release 141 Scope The present document is an introduction to the 06 series of the GSM technical specifications dealing with the Full rate speech processing functions in the GSM system. A general overview of the speech pr
21、ocessing parts is given with reference to the technical specifications where each part is specified in detail. 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 d
22、ate of publication, edition number, version number, etc.) or non-specific. For a specific reference, 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 implici
23、tly refers to the latest version of that document in the same Release as the present document. 1 GSM 01.04: “Digital cellular telecommunications system (Phase 2+); Abbreviations and acronyms“. 2 GSM 03.50: “Digital cellular telecommunications system (Phase 2+); Transmission planning aspects of the s
24、peech service in the GSM Public Land Mobile Network (PLMN) system“. 3 GSM 06.10: “Digital cellular telecommunications system (Phase 2+); Full rate speech; Transcoding“. 4 GSM 06.11: “Digital cellular telecommunications system (Phase 2+); Full rate speech; Substitution and muting of lost frames for f
25、ull rate speech channels“. 5 GSM 06.12: “Digital cellular telecommunications system (Phase 2+); Full rate speech; Comfort noise aspect for full rate speech traffic channels“. 6 GSM 06.31: “Digital cellular telecommunications system (Phase 2+); Full rate speech; Discontinuous Transmission (DTX) for f
26、ull rate speech traffic channels“. 7 GSM 06.32: “Digital cellular telecommunications system (Phase 2+); Voice Activity Detector (VAD) for full rate speech traffic channels“. 8 GSM 06.02: “Digital cellular telecommunications system (Phase 2+); Half rate speech; Half rate speech processing functions“.
27、 9 GSM 06.20: “Digital cellular telecommunications system (Phase 2+); Half rate speech; Half rate speech transcoding“. 10 GSM 06.21: “Digital cellular telecommunications system (Phase 2+); Half rate speech; Substitution and muting of lost frames for half rate speech traffic channels“. 11 GSM 06.22:
28、“Digital cellular telecommunications system (Phase 2+); Half rate speech; Comfort noise aspects for half rate speech traffic channels“. 12 GSM 06.41: “Digital cellular telecommunications system (Phase 2+); Half rate speech; Discontinuous Transmission (DTX) for half rate speech traffic channels“. 13
29、GSM 06.42: “Digital cellular telecommunications system (Phase 2+); “Half rate speech; Voice Activity Detector (VAD) for half rate speech traffic channels“. 3 Abbreviations Abbreviations used in the present document are listed in GSM 01.04 1. ETSI ETSI TS 146 001 V14.0.0 (2017-04)63GPP TS 46.001 vers
30、ion 14.0.0 Release 144 Introduction Figure 1 presents a reference configuration where the various speech processing functions are identified. In this figure, the relevant technical specifications for each function are also indicated. In figure 1, the audio parts including analogue to digital and dig
31、ital to analogue conversion are included to show the complete speech path between the audio input/output in the Mobile Station (MS) and the digital interface to the PSTN. The specification of the audio parts are contained in GSM 03.50 2 (Transmission plan aspects of the speech service in the GSM PLM
32、N system). These aspects are only considered in the GSM 06-series to the extent that the performance of the audio parts affect the performance of the speech transcoder. 5 Full rate speech transcoding (GSM 06.10) As shown in figure 1, the speech encoder takes its input as a 13 bit uniform PCM signal
33、either from the audio part of the mobile station 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 encoded speech at the output of the speech encoder is delivered to the channel coding function defined in GSM 05.03 to produce an encoded
34、 block consisting of 456 bits leading to a gross bit rate of 22,8 kbit/s. In the receive direction, the inverse operations take place. GSM 06.10 3 describes the detailed mapping between input blocks of 160 speech samples in 13 bit uniform PCM format to encoded blocks of 260 bits and from encoded blo
35、cks of 260 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 stream of 13 kbit/s. The coding scheme is the so-called Regular Pulse Excitation - Long Term prediction - Linear Predictive Coder, here-after r
36、eferred to as RPE-LTP. The technical specification describes the codec down to the bit level, thus enabling the verification of compliance to the technical specification to a high degree of confidence by use of a set of digital test sequences. These test sequences are also described and are availabl
37、e on floppy disks. 6 Full rate Discontinuous Transmission (DTX) (GSM 06.31) During a normal conversation, the participants alternate so that, on the average, each direction of transmission is occupied about 50 % of the time. Discontinuous transmission (DTX) is a mode of operation where the transmitt
38、ers 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 duration; 2) the average interference level on the “air“ is reduced, le
39、ading to better spectrum efficiency. The overall DTX mechanism is implemented in the DTX handlers (TX and RX) described in GSM 06.31 6 and requires the following functions which are described in separate technical specifications: - a Voice Activity Detector on the transmit side; - evaluation of the
40、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 noise, during periods where the radio transmission is cut. The transmission of comfort noise information to the rece
41、ive side is achieved by means of a special frame (Silence descriptor = SID). This frame is transmitted at the end of speech bursts and serves as an end of speech marker for the receive side. In order to update the comfort noise characteristics at the receive side, SID frames are transmitted at regul
42、ar intervals also during speech pauses. This also serves the purpose of improving the measurement of the radio link quality by the radio subsystem. For the overall DTX functionality, the DTX handlers interwork via various flags with the Radio Subsystem, which is in control of the actual transmitter
43、keying on the TX side and which performs various pre-processing functions on the RX side. This is also described in GSM 06.31 6. ETSI ETSI TS 146 001 V14.0.0 (2017-04)73GPP TS 46.001 version 14.0.0 Release 14A common terminology used throughout the GSM 06-series of technical specifications is also d
44、efined in the present document. 7 Full rate Voice Activity Detection (VAD) (GSM 06.32) The input to the VAD is a set of parameters computed by the full-rate speech encoder defined in GSM 06.10 3. The VAD uses this information to decide whether each 20 ms speech coder frame contains speech or not. No
45、te that the VAD flag is an input to TX DTX handler and does not control the transmitter keying directly. The technical specification describes the VAD algorithm down to the bit level. The conventions used in the bit-exact specification are the same as those used in GSM 06.10 3. The verification of c
46、ompliance to the technical specification is achieved by use of digital test sequences applied to the same interface as the test sequences for the speech codec. These test sequences are also described and are available on floppy disks. 8 Full rate comfort noise insertion (GSM 06.12) When switching th
47、e transmission on and off during DTX operation, the effect would be a modulation of the background noise at the receiving end if no precautions were taken. When transmission is on, the background noise is transmitted together with the speech to the receiving end. As the speech burst ends, the connec
48、tion is off and the perceived noise would drop to a very low level. This step modulation of noise is perceived as very annoying and may reduce the intelligibility of speech if presented to a listener without modification. This so-called “noise contrast effect“ is reduced in the GSM system by inserti
49、ng an artificial noise, termed comfort noise, at the receiving end when speech is absent. GSM 06.12 5 deals with the detailed aspects of the comfort noise process: - the evaluation of the acoustic background noise in the transmitter; - the noise parameter encoding (SID frames) and decoding; - and the generation of comfort noise in the receiver. The algorithm for updating the noise parameters during speech pauses is also defined. The comfort noise mechanism is based on the full rate speech codec defined in GSM 06.10 3. 9 Full
