1、INTERNATIONAL TELECOMMU N CATION UN ION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU G.991.1 (1 0/98) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital transmission systems - Digital sections and digital line system - Access networks High bit rate Digital Subscr
2、iber Line (HDSL) transceivers ITU-T Recommendation G.991.1 (Previously CCITT Recommendation) ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS INTERNA TIONAL ANALOGUE CARRIER SYSTEM GENERAL CHARACTERISTICS COM
3、MON TO ALL ANALOGUE CARRIER- TRANSMISSION SYSTEMS INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE WITH METALLIC LINES COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY SYSTEMS ON RADIO-RELAY OR SATELLI
4、TE LINKS AND INTERCONNECTION Radiotelephone circuits Links with mobile stations TESTING EQUIPMENTS TRANSMISSION MEDIA CHARACTERISTICS DIGITAL TRANSMISSION SYSTEMS TERMINAL EQUIPMENTS DIGITAL NETWORKS DIGITAL SECTIONS AND DIGITAL LINE SYSTEM General Parameters for optical fibre cable systems Digital
5、sections at hierarchical bit rates based on a bit rate of 2048 kbitk Digital line transmission systems on cable at non-hierarchical bit rates Digital line systems provided by FDM transmission bearers Digital line systems Digital section and digital transmission systems for customer access to ISDN Op
6、tical fibre submarine cable systems Optical line systems for local and access networks Acce warks G. 100-G. 1 99 G .200-G .299 G.300-G.399 G.400-G.449 G.450-G.499 G.450-G.469 G.470-G.499 G. 600-G .699 G.700-G.799 G.800-G.899 G.900-G.999 G.900-G.909 G.910-G.919 G.920-G.929 G .930-G .939 G ,940-G .949
7、 G .950-G .959 G.960-G.969 G.970-G.979 G .980-G .989 For further derails. please refer ta iTU-T LLrt of Recommendationr. ITU-T RECOMMENDATION 6.991.1 HIGH BIT RATE DIGITAL SUBSCRIBER LINE (HDSL) TRANSCEIVERS Summary This Recommendation specifies a High bit rate Digital Subscriber Line (HDSL) which i
8、s a bidirectional and symmetrical transmission system that aliows the transport of signals with a bit rate of 1544 kbit/s or 2048 kbit/s on the copper twisted pairs of an access network. The basic work has been carried out in the ANSI T1 committee for 1544 kbit/s signals. The results of this work we
9、re taken by TM6 of ETSI and adopted for 2048 kbit/s signais in a technical specification, which built the basis for this Recommendation. The HDSL system uses echo cancellation technique for the separation of the directions of transmission, so that one twisted pair can carry both directions. Two diff
10、erent options for the line code are recommended, the Pulse Amplitude Modulation 2B 1 Q and the Carrierless AmplitudePhase Modulation CAP. CAP is applicable for 2048 kbit/s only, while for 2B1Q two different frames for 1544 kbit/s and 2048 kbit/s are defined. The 2B1Q for 2048 kbitfs caters for both
11、duplex transmission on a single pair and parallel transmission on two or three-pairs. This allows for the distribution of the signal to several pairs and for reduction of the symbol rate and an increase of the line length. CAP is defined for one- or two-pairs only and the 1544 kbit/s 2B 1 Q for two-
12、pairs only. Source lTU-T Recommendation G.991.1 was prepared by lTU-T Study Group 15 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 13th of October 1998. Recommendation 6.991.1 (10/98) I - STD.ITU-T RECMN G.99L-L-ENGL 1998 48b259L Obb7457 790 m FOREWORD lTU (Internatio
13、nal Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The KU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendatio
14、ns on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. The
15、approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. NOTE In this Recommendatio
16、n the term recognized operating agency (ROA) includes any individual, company, corporation or governmental organization that operates a public correspondence service. The terms Administration, ROA and public correspondence are defined in the Constitution ojthe ITU (Genevu, 1992). INTELLECTUAL PROPER
17、TY RIGHTS The IT draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether a
18、sserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, the IT had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautione
19、d that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. o ITU 1999 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microf
20、ilm, without pennission in writing from the ITU. 11 Recommendation G391.1 (lo/%) STD-ITU-T RECMN G.99L-L-ENGL L998 48b259L Obb7458 b27 D CONTENTS Page 1 Scope 1 2 References 1 3 Abbreviations . 2 4 Reference configuration and functional description . 3 5 HDSL core specification 6 5.1 Functions Trans
21、parent transport of core frames 5.1.1 5.1.2 Stuffing and destufng 5.1.4 Error reporting . 5.1.6 Failure reporting 5.1.3 CRC-6 procedures and transmission error detection 5.1.5 Failure detection 5.1.7 Bit timing 5.1.8 Frame alignment 5.1.9 HDSL transceiver autonomous start-up control 5.1.10 Loopback
22、control and coordination . 5.1.11 Mapping between core frames and HDSL frames 5.1.12 Control of the maintenance channel 5.1.13 Synchronization and coordination of HDSL transceivers . 5.1.14 Identification of pairs 5.1.15 Correction of pair identification 5.1.16 Remote power feeding 5.1.17 Wetting cu
23、rrent 6 7 7 7 7 7 7 7 7 7 8 8 8 8 8 8 8 8 5.2 Transmission medium 8 5.2.1 Description 8 5.2.2 Minimum Digital Local Line (DLL) requirements for HDSL applications 9 5.2.3 DLL physical characteristics . 9 5.2.4 DLL electrical characteristics 10 5.3 Transmission method . 11 5.3.1 General 11 5.3.2 Trans
24、mission on three-pairs 12 5.3.3 Transmission on two-pairs 12 12 5.3.4 Transmission on one-pair 12 5.3.5 Transmission on four-pairs . 5.3.6 Line code . 12 5.3.7 Line symbol rate 13 . Recommendation 6.991.1 (lo/%) 1U 5.4 5.5 5.6 5.7 5.8 5.9 6 6.1 Frame structure . 5.4.1 Core frame . 5.4.2 2B 1 Q HDSL
25、frame 5.4.3 Scrambling method . HDSL embedded operations channel (eoc) 5.5.1 Functions of the HDSL eoc . 5.5.2 HDSL eoc acknowledgement protocol . 5.5.3 The HDSL eoc data readwrite mode 5.5.4 HDSL eoc-message list . 5 S.5 5.5.6 5.5.7 Noise margin . HDSL eoc-message set requirements Data registers in
26、 the NTU and in regenerators Start-up procedure Control and status signais . 5.6.3 Transmitted signals . 5.6.1 General 5.6.2 5.6.4 Timers . 5.6.5 Activation state diagrams 5.6.6 Regenerator related procedures . Operation and maintenance Functions at the LTU external OAM reference point . Functions a
27、t the NTU external OAM reference point . 5.7.1 5.7.2 5.7.3 5.7.4 OAM messages and functions supported by the HDSL core Power feeding related OAM functions 5.7.5 Regenerator behaviour Electrical characteristics of a single 2B1Q transceiver 5.8.1 General 5.8.2 Transmitter/receiver impedance and return
28、 loss . 5.8.3 Transceiver reference clock 5.8.4 Transmitter output characteristics . 5.8.5 Unbalance about earth . Performance of individual HDSL transceivers . 5.9.1 Performance requirements 5.9.2 5.9.3 Jitter and wander . DLL physical models (test loops) . Common circuitry specification . Delay di
29、fference buffer . Page 13 13 14 27 29 30 31 33 36 37 39 40 41 41 42 43 44 45 51 55 55 56 57 59 59 60 60 60 62 62 66 69 69 69 69 70 70 iv Recommendation 6.991.1 (10/98) STD.ITU-T RECMN G.99L-L-ENGL 1998 9 48b2591i ObbLib0 285 6.2 6.3 7 7.1 7.2 7.3 8 8.1 8.2 8.3 8.4 The pair identification mechanism .
30、 6.2.1 Pair identification initial values 6.2.2 Pair identification at the NTU . 6.2.3 Pair identification at the LTU . Laboratory performance measurements . 6.3.1 General 6.3.2 Test configuration . 6.3.3 6.3.4 6.3.5 Test procedure with shaped noise . Test procedure for impulse noise Common mode rej
31、ection test 6.3.6 Micro interruption test Power feeding . General . Wetting current . Remote power feeding aspects . 7.3.1 Remote power feeding aspects at the LTU . 7.3.2 Remote power feeding aspects at the NTU . 7.3.3 Remote power feeding aspects at the regenerator . Environmental requirements Clim
32、atic conditions Safety Overvoltage protection . Electromagnetic compatibility (EMC) . Annex A . Transmission system for 1544 kbit/s two-pair system application . A.l Frame structure of the two-pair system for 784 kbit/s Annex B - High bit rate Digital Subscriber Line (HDSL) CAP based system . B.l Sc
33、ope and general information . B.l.l Scope . B.2 References B.3 Abbreviations . B.4 Reference configuration and functional description . B.5 HDSL core specification B.5.1 Functions . B.5.2 Transmission medium . B.5.3 Transmission method B.5.4 Frame stnicture Recommendation G.991.1 (10/98) Page 71 71
34、71 71 72 72 73 77 78 80 80 81 81 81 81 82 82 82 82 82 83 83 83 83 83 86 86 86 86 86 87 87 87 87 87 93 V B.5.5 HDSL embedded operations channel (eoc) . B.5.6 Start-up procedure . B.5.7 Operation and maintenance . B.5.8 Electrical characteristics of CAP-based transceivers B.5.9 Performance of individu
35、al HDSL transceivers . B.6 Common circuitry specification . B.6.1 Delay difference buffer . Laboratory performance measurement tests B.7 Power feeding . B.8 Environmental requirements B.6.2 Appendix I - Application specific examples . 1.1 Application specific requirements for ISDN PRA with 2048 kbit
36、/s 1.1.1 Mapping of 2048 kbit/s to HDSL 1.1.2 Mapping of HDSL maintenance functions to the interface . 1.1.3 Performance 1.2 1.3 Application specific requirements for the European 2048 kbit/s digital unstructured leased line (D2048U) 1.2.1 Application interfaces . Mapping of the D2048U signal to HDS
37、L . . 1.2.2 1.2.3 Mapping of HDSL maintenance functions to the interface . 1.2.4 Performance Application specific requirements for the European 2048 kbit/s digital structured leased line (D2048S) 1.3.1 Application interfaces . 1.3.2 Mapping of the D2048S signal to HDSL 1.3.3 Mapping of HDSL maintena
38、nce functions to the interface . 1.3.4 Performance 1.4 Application specific requirements for fractional installation . 1.4.1 1.4.2 Mapping of HDSL maintenance functions to the interface . 1.4.3 Performance Mapping of fractional services to HDSL 1.5 Application specific requirements for partial opera
39、tion . 1.5.1 Mapping of the application frame for partial operation application . 1.5.2 Mapping of HDSL maintenance functions to the interface . 1.5.3 Performance 1.5.4 Remote power feeding 1.5.5 Partial failure criteria . vi Recommendation 6.991.1 (lo/%) Page 100 100 118 119 123 125 125 125 128 128
40、 128 128 128 128 129 132 132 132 132 133 134 134 135 135 136 137 137 143 144 144 144 147 147 148 148 1.5.6 Action following partial failure . 1.5.7 Time slot prioritizatiodreallocation 1.6 Application specific requirements for the 2048 kbith mapped into TU-12 structure 1.6.1 Reference Configuration
41、. 1.6.2 Application Interfaces . 1.6.3 Mapping of application frame into HDSL using TU-12 structure 1.6.4 Mapping of HDSL maintenance functions to the interface . 1.6.5 Performance Appendix II . Detailed definition of cable characteristics and test loops . 11.1 11.2 Typical characteristics of cables
42、 . Appendix III - Bibliography Theoretical characteristics of test loops for Y = 31 dB at 150 kJ3z . Page 148 148 149 149 149 149 153 153 155 155 157 159 Recommendation 6991.1 (10/98) Vii STDmITU-T REC“ G-991.1-ENGL 1998 4862591 Obb74b3 T94 Recommendation G.991.1 HIGH BIT RATE DIGITAL SUBSCRIBER LIN
43、E (HDSL) TRANSCEIVERS (Geneva, 1998) 1 Scope This Recommendation describes a transmission technique cailed High bit rate Digital Subscriber Line (HDSL), as a means for the transportation of several types of applications. This Recommendation defines the requirements for the individual HDSL transmissi
44、on system, the transmission performance, the HDSL maintenance requirements and procedures. An individual HDSL transceiver system is a two-wire bidirectional transceiver for metallic wires using the echo cancellation method. Three systems may be utilized, one transporting a bit rate of 784 kbit/s ove
45、r each of two or three-pairs used in parallel, a second with an increased bit rate of 1168 kbit/s and two-pairs in parallel only, and a third with a more increased bit rate of 2320 kbit/s on one-pair only. The line code of systems specified in this Recommendation is 2B1Q and CAP. The implementor may
46、 choose one or the other of these alternatives, only one line code has to be realized in a transmission system. In the main body of this Recommendation, system with 2B1Q for 2048 kbit/s applications are described. In Annex A, the Committee T1 recommendation for the frame structure of 1544 kbit/s app
47、lications on two-pairs is described. Systems using a CAP line code are covered in Annex B. This Recommendation defines the common circuitry for combining and controlling one, two or three HDSL transceiver systems, depending on the bit rate of the transceiver system used. The common circuitry and the
48、 necessary number of HDSL transceiver systems form the HDSL core, which is independent from the possible applications. This Recommendation does not specify all the requirements for the implementation of NTU, LTU or REG. It serves only to describe the functionality needed. Examples for applications o
49、f HDSL are given in Appendix I. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; ail users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is r
