1、 International Telecommunication Union ITU-T G.767TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Corrigendum 1(05/2006) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital terminal equipments Principal characteristics of transcoder and digital multiplication equipment Dig
2、ital circuit multiplication equipment using 16 kbit/s LD-CELP, digital speech interpolation and facsimile demodulation/remodulation Corrigendum 1 ITU-T Recommendation G.767 (1998) Corrigendum 1 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL
3、TELEPHONE CONNECTIONS AND CIRCUITS G.100G.199 GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER-TRANSMISSION SYSTEMS G.200G.299 INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES G.300G.399 GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS O
4、N RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES G.400G.449 COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY G.450G.499 TRANSMISSION MEDIA CHARACTERISTICS G.600G.699 DIGITAL TERMINAL EQUIPMENTS G.700G.799 General G.700G.709 Coding of analogue signals by pulse code modulation
5、 G.710G.719 Coding of analogue signals by methods other than PCM G.720G.729 Principal characteristics of primary multiplex equipment G.730G.739 Principal characteristics of second order multiplex equipment G.740G.749 Principal characteristics of higher order multiplex equipment G.750G.759 Principal
6、characteristics of transcoder and digital multiplication equipment G.760G.769 Operations, administration and maintenance features of transmission equipment G.770G.779 Principal characteristics of multiplexing equipment for the synchronous digital hierarchy G.780G.789 Other terminal equipment G.790G.
7、799 DIGITAL NETWORKS G.800G.899 DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900G.999 QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DATA OVER TRANSPORT GENERIC ASPECTS G.7000G.7999 PACKET OVER TRANSPORT ASPECTS G.8000G.
8、8999ACCESS NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. G.767 (1998)/Cor.1 (05/2006) i ITU-T Recommendation G.767 Digital circuit multiplication equipment using 16 kbit/s LD-CELP, digital speech interpolation and facsimile demodulation/remo
9、dulation Corrigendum 1 Summary This Recommendation specifies the elements of DCME using 16 kbit/s LD-CELP, Digital Speech Interpolation (DSI) and Facsimile Demodulation/Remodulation in order to achieve interworking of such equipment. It specifies extensions and deviations for ITU-T Recs G.763 and G.
10、766 which specify a 32 kbit/s ADPCM DCME, and Facsimile Demodulation/Remodulation. Corrigendum 1 corrects a number of defects identified in the base text which had been previously documented in Implementors Guides. Source Corrigendum 1 to ITU-T Recommendation G.767 (1998) was approved on 29 May 2006
11、 by ITU-T Study Group 16 (2005-2008) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. G.767 (1998)/Cor.1 (05/2006) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardizatio
12、n 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 (WTSA), which meets
13、 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 fall within ITU-Ts pu
14、rview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is vo
15、luntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and t
16、he negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involv
17、e 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 by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recomm
18、endation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. ITU 20
19、06 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. G.767 (1998)/Cor.1 (05/2006) 1 ITU-T Recommendation G.767 Digital circuit multiplication equipment using 16 kbit/s LD-CELP, digital speech interpola
20、tion and facsimile demodulation/remodulation Corrigendum 1 Modifications introduced by this corrigendum are shown in revision marks. Unchanged text is replaced by ellipsis (). Some parts of unchanged texts (clause numbers, etc.) have been kept to indicate the correct insertion points. 1 Scope This R
21、ecommendation specifies the elements of DCME using 16 kbit/s LD-CELP, Digital Speech Interpolation (DSI) and facsimile demodulation/remodulation (namely a 16 kbit/s DCME) in order to achieve interworking of such equipment. It is an extension to ITU-T Recs G.763 (Digital Circuit Multiplication Equipm
22、ent Using 32 kbit/s ADPCM and Digital Speech Interpolation) and G.766 (Facsimile Demodulation/Remodulation for DCME), as it specifies only the deviations of the 16 kbit/s DCME from the G.763 32 kbit/s DCME. 5.1.1 Supported services The 16 kbit/s DCME frame structure accommodates the following servic
23、es: 8-bit channels to support 64 kbit/s transparent calls. 2-bit channels to support voice calls at LD-CELP 16 kbit/s, 12.8 kbit/s, 9.6 kbit/s according to ITU-T Rec. G.728 and its Annex H. 5-bit channels to support VBD calls at LD-CELP at 40 kbit/s according to ITU-T Rec. G.728 and its draft Annex
24、J. 4-bit channels to support fax banks carrying demodulated fax calls similar to ITU-T Recs G.763 and G.766. 8-, 5-, 2-bit channels to support 64 kbit/s, 40 kbit/s, 16 kbit/s, 12.8 kbit/s and 9.6 kbit/s pre-assigned channels. 5.1.4 DCME multiframe The IT related circuit supervision/alarm condition f
25、ield of the asynchronous word supports up to 360 ITs, fromcarried over up to 12 primary rate interfaces. The G.767 DCME multiframe of 72 DCME frames is used to accommodate that. 2 ITU-T Rec. G.767 (1998)/Cor.1 (05/2006) 6.1.1 Number of cliques With LD-CELP, small cliques (compared to G.763 DCME) can
26、 support a fairly large amount of traffic. Therefore the maximum number of cliques (pools) carried on a single bearer in 16 kbit/s DCME is increased to 4. Each pool starts and ends on TS boundaries (and therefore occupies an integral number of time slots); a clique shall not be split across bearers.
27、 6.1.2 Number of destinations The maximum number of destinations is 4 including the cases of mixed operation between multi-clique and multi-destination modes. 6.1.3 Multiple outgoing bearers Optionally, a 16 kbit/s DCME will support up to 4 outgoing bearers. A single bearer will be able to carry up
28、to 4 cliques. A clique shall not be split across bearers. 6.2 Assignment Messages (AM) 6.4 Control Channel (CC) A single AM control channel of the 16 kbit/s DCME occupies 4 bits every PCM frame, i.e., 2 QBs. The single AM control channel holds the synchronization word, an assignment message (IT and
29、BC numbers and synchronous data word), the asynchronous data word and some error correction bits. When an additional assignment message in the same DCME frame is required (double AM), one additional QB supports it and the additional error correction bits. 6.5 BC numbering and the use of the bearer f
30、rame 6.5.2 5-bit (VBD optimized 40 kbit/s LD-CELP) BCs The BC number in the assignment message indicates the BC which carries the first 2 bits (MSB, MSB 1) of the 5-bit sample. The next higher BC carries the next 2 bits (MSB 2, MSB 3) (LSB + 2, LSB + 1). The 5th bit (LSB) is obtained from a differen
31、t 4-bit bearer channel which is independently assigned as a Bit Bankbit bank; the procedure is as in 6.1.7/G.763. Also, similarSimilarly to ITU-T Rec. G.763, all 4-bit BCs (Data, FB or BB) occupy either the four MSBs or the four LSBs of a G.704 time slot. This implies that the BC number in the assig
32、nment message, for such BCs, is an odd number. 6.5.3 4-bit BCs (BB, FB) 16 kbit/s DCME fax banks and bit banks are used in the same manner as they are used in ITU-T Recs G.763/G.766. The BC number in the assignment message indicates the BC which carries the first 2 bits of the 4-bit sample. The next
33、 higher BC carries the remaining 2 bits2 more bits. 6.5.4 Normal range 2-bit BCs (LD-CELP voice) ITU-T Rec. G.767 (1998)/Cor.1 (05/2006) 3 7.2.2 Total number of assignment messages The total number of assignment messages per transmit unit (see clause 6/G.763)Tx unit is 5. 7.3 Control channel content
34、 7.3.2.1 IT Identification word The 9 bits of the IT identification word is used to identify the ITs. IT numbering is given in Table 1. Table 1/G.767 Numbers of ITs used in assignment messages IT number IT identification 511 Ineffective CC message when all traffic is pre-assigned. all others Reserve
35、d for future use 7.3.2.2 BC identification word 9 ABPS calculations For the purpose of DLC calculations and thresholds and performance statistic, given an ADPCM bit per sample measure, its equivalent LD-CELP measure is: BL= 0.4 (BA+ 1) where BLis the LD-CELP bit per sample measure and BAis the ADPCM
36、 bit per sample measure. For example, the LD-CELP equivalent of an ADPCM ABPS of 3.7 bits/sample is 0.4 (3.7 + 1) = 1.88 bits/sample. 109 Channel check procedure 1110 Facsimile demodulation/remodulation 1110.1 General 1110.2 Facsimile blocks, facsimile transport channels and fax banks 1110.3 Facsimi
37、le data channel 4 ITU-T Rec. G.767 (1998)/Cor.1 (05/2006) 1110.4 Facsimile control channel and forward error correction The generator polynomial for BCH(63,51) is: 134581012+ xxxxxx 1110.5 FCC location on the bearer 1211 System statistics measurement Printed in Switzerland Geneva, 2006 SERIES OF ITU
38、-T RECOMMENDATIONS Series A Organization of the work of ITU-T Series D General tariff principles Series E Overall network operation, telephone service, service operation and human factors Series F Non-telephone telecommunication services Series G Transmission systems and media, digital systems and n
39、etworks Series H Audiovisual and multimedia systems Series I Integrated services digital network Series J Cable networks and transmission of television, sound programme and other multimedia signals Series K Protection against interference Series L Construction, installation and protection of cables
40、and other elements of outside plant Series M Telecommunication management, including TMN and network maintenance Series N Maintenance: international sound programme and television transmission circuits Series O Specifications of measuring equipment Series P Telephone transmission quality, telephone
41、installations, local line networks Series Q Switching and signalling Series R Telegraph transmission Series S Telegraph services terminal equipment Series T Terminals for telematic services Series U Telegraph switching Series V Data communication over the telephone network Series X Data networks, open system communications and security Series Y Global information infrastructure, Internet protocol aspects and next-generation networks Series Z Languages and general software aspects for telecommunication systems
