1、COVERING NOTE GENERAL SECRETARIAT INTERNATIONAL TELECOMMUNICATION UNION Geneva, 29 July 2003 ITU -TELECOMMUNICATION STANDARDIZATION SECTOR Subject: Erratum 1 (07/2003) to ITU-T Recommendation G.722.2 Annex B (01/2002), Wideband coding of speech at around 16 kbith using Adaptive Multi-Rate Wideband (
2、AMR- WB) - Annex B: Source Controlled Rate operation Correct clause numbering as follows: B.4.2.32 Demands on the RX SCR handler Union internationale des tlcommunications Place des Nations 121 1 GENVE 20 Suisse - Switzerland - Suiza JTERN. TIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STAND
3、ARDIZATION SECTOR OF ITU G.722.2 Annex B (01/2002) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital terminal equipments - Coding of analogue signals by methods other than PCM Wideband coding of speech at around 16 kbit/s using Adaptive Multi-Rate Wdeband (AMR-WB) Annex
4、B: Source Controlled Rate operation ITU-T Recommendation G.722.2 - Annex B INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU G.722.2 Annex B (O1 /2002) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital terminal equipments - Codin
5、g of analogue signals by methods other than PCM Wideband coding of speech at around 16 kbits using Adaptive Multi-Rate Wideband (AMR-WB) Annex B: Source Controlled Rate operation ITU-T Recommendation G.722.2 - Annex B ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND
6、 NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS TRANSMISSION SYSTEMS GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER- iNDMDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES GENERAL CHARACTERISTICS OF INERNATIONAL CARRIER TELEPHONE METALLIC LINES COORD
7、INATION OF RADIOTELEPHONY AND LINE TELEPHONY TESTING EQUIEMENTS TRANSMISSION MEDIA CHARACTERISTICS DIGITAL TERMINAL EQUIEMENTS SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WKJ3 General G. 1 00-G. 199 G.200-G.299 G.300-G.399 G.400-G.449 G.450-G.499 G.500-G.599 G.600-G.699 G.700-G.799
8、 G.700-G.709 Coding of analogue signals by pulse code modulation Principal characteristics of primary multiplex equipment G.710-G.719 G.730-G.739 Principal characteristics of second order multiplex equipment Principal characteristics of higher order multiplex equipment Principal characteristics of t
9、ranscoder and digital multiplication equipment Operations, administration and maintenance features of transmission equipment Principal characteristics of multiplexing equipment for the synchronous digital hierarchy Other terminal equipment DIGITAL NETWORKS DIGITAL SECTIONS AND DIGITAL LINE SYSTEM QU
10、ALITY OF SERVICE AND PERFORMANCE TRANSMISSION MEDIA CHARACTERISTICS General Symmetric cable pairs Land coaxial cable pairs Submarine cables Optical fibre cables Characteristics of optical components and subsystems General Coding of analogue signals by pulse code modulation Coding of analogue signals
11、 by methods other than PCM Principal characteristics of primary multiplex equipment Principal characteristics of second order multiplex equipment Principal characteristics of higher order multiplex equipment Principal characteristics of transcoder and digital multiplication equipment Operations, adm
12、inistration and maintenance features of transmission equipment Principal characteristics of multiplexing equipment for the synchronous digital hierarchy Other terminal equipment General aspects Design objectives for digital networks Quality and availability targets Network capabilities and functions
13、 SDH network characteristics Management of transport network SDH radio and satellite systems integration Optical transport networks DIGITAL TERMINAL EQUIPMENTS DIGITAL NETWORKS G.740-G.749 G.750-G.759 G.760-G.769 G.770-G.779 G.780-G.789 G.790-G.799 G.800-G.899 G.900-G.999 G. 1000-G.1999 G.6000-G.699
14、9 G.6000-G.6099 G.6 100-G.6199 G.6300-G.6499 G.6600-G.6999 G.7000-G.7999 G.7000-G.7099 G.7 100-G.7199 G.7200-G.7299 G.73 00-G.73 99 6.74004.7499 G.7500-G.7599 G.7600-G.7699 G.7700-G.7799 G.7800-G.7899 G.6200-G.6299 G.6500-G.6599 G.7900-G.7999 G.8000-G.8999 G.8000-G.8099 G.8100-G.8199 G.8200-G.8299 G
15、. 8400-G. 8499 G.8500-G.8599 G. 8600-G. 8699 G. 8700-G.8799 G. 83 OO-G. 83 99 For further details, please refer to the list of ITU-TRecomrnendations. ITU-T Recommendation 6.722.2 Wideband coding of speech at around 16 kbit/s using Adaptive Multi-Rate Wideband (AMR-WB) Annex B Source Controlled Rate
16、operation Summary This annex describes the operation of the adaptive multi-rate wideband speech codec during Source Controlled Rate (SCR) operation. The SCR operation described here was also adopted by 3GPP in 3GPP specification TS 26.193. Source Annex B to ITU-T Recommendation G.722.2 was prepared
17、by ITU-T Study Group 16 (2001-2004) and approved under the WTSA Resolution 1 procedure on 13 January 2002. ITU-T Rec. G.722.21Annex B (0112002) i FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunic
18、ation Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly
19、 (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which f
20、all within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL, PROPERT
21、Y RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted
22、by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this
23、 may not represent the latest information and are therefore strongly urged to consult the TSB patent database. O ITU 2002 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. 11 ITU-T Rec. G.722.2/Annex B (OU2002) C
24、ONTENTS Page Annex B . Source controlled rate operation B . 1 B.2 B.2.1 B.2.2 B.2.3 B.3 B.3.1 B.4 B.4.1 B.4.2 B.4.3 Scope Definitions. symbols and abbreviations . Symbols Abbreviations . General . General organisation Definitions AMR-WB SCR operation Transmit (TX) side . Receive (RX) side AMR-WB SID
25、 Information format 1 1 1 1 1 1 2 2 3 3 6 7 ITU-T Rec . G.722.2/Annex B (01/2002) iii ITU-T Recommendation G.722.2 Wideband coding of speech at around 16 kbit/s using Adaptive Multi-Rate Wideband (AMR-WB) Annex B Source Controlled Rate operation B.l Scope This annex describes the Source Controlled R
26、ate (SCR) operation (also called Discontinuous Transmission, DTX) of the Adaptive Multi-Rate Wideband speech codec. Implementation of this annex is necessary for interoperability with 3GPP systems, but its use is not limited to mobile applications. The description is structured according to the bloc
27、k diagram in Figure B.l. This structure of distributing the various functions between system entities is not mandatory for implementation, as long as the operation on the speech decoder output remains the same. B.2 Definitions, symbols and abbreviations B.2.1 Definitions This annex, defines the foll
28、owing terms. B.2.1.1 frame: Time interval of 20 ms, corresponding to the time segmentation of the Adaptive Multi-Rate Wideband speech Codec, also used as a short term for a traffic frame. B.2.1.2 traffic frame: Block of 132477 information bits transmitted on the speech traffic channels. B.2.1.3 SID
29、frame: Frame that conveys information about the acoustic background noise. B.2.1.4 speech frame: Traffic frame that has been classified as SPEECH-GOOD, SPEECH - BAD or SPEECH-LOST frame. B.2.1.5 VAD flag: Boolean flag, generated by the VAD algorithm indicating the presence (“1“) or the absence (“O“)
30、 of a speech frame. B.2.1.6 =-TYPE: Classifies the received frame. B.2.1.7 TX-TYPE: Classifies the frame to be transmitted. B.2.1.8 hangover period: A period of frames added at the end of a speech burst in which VAD flag = “O“ and TX-TYPE is = SPEECH-GOOD“, this period provides the encoder with an e
31、xtra window to derive the Comfort Noise parameters. B.2.2 Symbols This annex uses the following symbol: Nelapsed Number of elapsed frames since the last updated SID frame. B.2.3 Abbreviations This annex uses the following abbreviations: AN Access Network RAN Radio Access Network ITU-T Rec. G.722.21A
32、nnex B (01/2002) 1 Rx SCR SID TS TX UE VAD B.3 Receive Source Controlled Rate (operation) Silence Insertion Descriptor Telecommunication Standard, Technical Specification Transmit User Equipment Voice Activity Detector General Source Controlled Rate operation (SCR) is a mechanism for the AMR Wideban
33、d Speech codec, which allows to encode the input signal at a lower average rate by taking speech inactivity into account. The SCR scheme may be used for the following purposes: - to save power in the User Equipment; - to reduce the overall interference and load in the networks. SCR in the transmitti
34、ng path (uplink) shall be in operation in UEs, if commanded so by the network. The UE shall handle SCR in the receiving path (downlink) at any time, regardless whether SCR in the transmitting path is commanded or not. B.3.1 General organisation The default SCR mechanism described in this annex requi
35、res the following functions: - - a Voice Activity Detector (VAD) on the transmit (TX) side; evaluation of the background acoustic noise on the transmit (TX) side, in order to transmit characteristic parameters to the receive (RX) side; generation on the receive (RX) side of a similar noise, called c
36、omfort noise, during periods where the transmission is switched off. The Voice Activity Detector WAD) is defined in the main body of ITU-T Rec. G.722.2 and the comfort noise functions in AnnexNG.722.2. Both are based partly on the speech Codec and its internal variables, defined in the main body of
37、ITU-T Rec. G.722.2. In addition to these functions, if the parameters arriving at the RX 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. These functions are defin
38、ed in Appendix UG.722.2. An overview of one link SCR operation is shown in Figure B. 1. - 2 ITU-T Rec. G.722.2/A.nnex B (01/2002) “Network“ RX SCR handler encoder parameter TX SCR handler Information bits FX Information bits Mode indication 3 Frame type TX-TYPE : FQI e4 information rl w W .c activit
39、y parameter n Information bits Mode indication Information packeting, transport and I classification I- concealment Mode indication Rx-TYPE Comfort noise I generation TI61 0090-02 Figure B.UG.722.2 - Block diagram of one link SCR operation B.4 AMR-WB SCR operation B.4.1 Transmit (TX) side A block di
40、agram of the transmit side SCR functions is shown in Figure B.2. TX SCR handler Framing TX Access Network T1610100-02 Figure B.2/6.722.2 - Block diagram of SCR functions at the TX side B.4.1.1 General operation The TX SCR handler passes traffic fiames, individually marked by TX-TYPE, to the Framing
41、unit. Each frame consists of bit fields containing the information bits, the codec mode indication, and the TX TYPE. TX TYPE shall be used to speciQ the contents of the frame. Table B.l provides an overview of thedifferent TX-TYPES used and explains the required contents in the information bit and t
42、he mode indication bit fields. ITU-T Rec. G.722.2/Annex B (01/2002) 3 Table B.UG.722.2 - SCR TX-TYPE identifiers SIDBAD TX-TYPE I Information bits I Mode indication Corrupt SID update frame (bad CRC) The codec mode that would have been used if TX-TYPE had been “SPEECH GOOD“ SPEECH-GOOD SPEECH-BAD Sp
43、eech frame, size 132477 bits, deDending. on codec mode Corrupt speech fi-ame (bad CRC), size 132477 bits, depending on codec mode Current codec mode Current codec mode SPEECH-LOST SIDFIRST SID-UPDATE No useful information (NOTE - If implementation does not support the SPEECH-LOST, SPEECH-BAD shall b
44、e used instead.) Marker for the end of talkspurt, no further information, all 35 comfort noise bits set to “O“ 35 comfort noise bits No useful information The codec mode that would have been used if TX-TYPE had been “SPEECH GOOD“ The codec mode that would have been used if TX-TYPE had been “SPEECHpG
45、OOD“ NO-DATA I No useful information, nothing to be I No useful information I transmitted I TX TYPE = “SPEECH-LOST“ indicates that the Information Bit and Codec Mode fields do not contain any useful data (but still should be transmitted over AN). The purpose of this TX TYPE is to indicate that the f
46、rame was transmitted but lost on some previous phase. This TX-T%E may occur only in Tandem Free Operation and Transcoder Free Operation situations. Note that it is possible to replace SPEECH-LOST with SPEECH-BAD but this may degrade the quality of the error concealment in the receiving end because c
47、oncealment may try to use part of the received parameters from the frame which do not contain any useful information. TX TYPE = “NO DATA“ indicates that the Information Bit and Codec Mode fields do not contain anyuseful data (and should not be transmitted over AN). The purpose of this TX-TYPE is to
48、provide the option to save network transmission between the transcoder and AN. Note that the TX-TYPES “SPEECH-BAD“, “SPEECH-LOST“ and “SID-BAD“ may occur in Tandem Free Operation and Transcoder Free Operation situations. The scheduling of the frames for transmission on the Access Network is controll
49、ed by the TX SCR handler by the use of the TX-TYPE field. B.4.1.2 If TX SCR operation is disabled, the TX SCR handler continuously generates speech fiames, i.e. frames marked with TX-TYPE = “ SPEECH-GOOD“. If the TX SCR operation is enabled, the VAD flag controls the TX SCR handler operation as described in the following paragraphs. Functions of the TX SCR handler 4 ITU-T Rec. G.722.2/Annex B (01/2002) B.4.1.2.1 AMR-WB SCR timing procedures To allow an exact verification of the TX SCR handler functions, all fiames before the reset of the system are treated as if there were speech f
