1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T G.991.2TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (12/2003) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital sections and digital line system Access networks Single-pair high-speed digital subscriber line (SHDSL) transce
2、ivers ITU-T Recommendation G.991.2 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS G.100G.199 GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER-TRANSMISSION SYSTEMS G.200G.299 INDIVIDUAL CHARACTERISTICS
3、 OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES G.300G.399 GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES G.400G.449 COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY G.450G.499 TESTING EQUIPM
4、ENTS G.500G.599 TRANSMISSION MEDIA CHARACTERISTICS G.600G.699 DIGITAL TERMINAL EQUIPMENTS G.700G.799 DIGITAL NETWORKS G.800G.899 DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900G.999 General G.900G.909 Parameters for optical fibre cable systems G.910G.919 Digital sections at hierarchical bit rates bas
5、ed on a bit rate of 2048 kbit/s G.920G.929 Digital line transmission systems on cable at non-hierarchical bit rates G.930G.939 Digital line systems provided by FDM transmission bearers G.940G.949 Digital line systems G.950G.959 Digital section and digital transmission systems for customer access to
6、ISDN G.960G.969 Optical fibre submarine cable systems G.970G.979 Optical line systems for local and access networks G.980G.989 Access networks G.990G.999 QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DIGITAL TERMINAL
7、EQUIPMENTS G.7000G.7999 DIGITAL NETWORKS G.8000G.8999 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. G.991.2 (12/2003) i ITU-T Recommendation G.991.2 Single-pair high-speed digital subscriber line (SHDSL) transceivers Summary This Recommendation describes a transm
8、ission method for data transport in telecommunications access networks. SHDSL transceivers are designed primarily for duplex operation over mixed gauge two-wire twisted metallic pairs. Optional multi-pair operation is supported for extended reach applications. Optional signal regenerators for both s
9、ingle-pair and multi-pair operation are specified, as well. SHDSL transceivers are capable of supporting selected symmetric user data rates in the range of 192 kbit/s to 2312 kbit/s using a Trellis Coded Pulse Amplitude Modulation (TCPAM) line code. Optional extensions described in Annex F allow use
10、r data rates up to 5696 kbit/s. SHDSL transceivers are designed to be spectrally compatible with other transmission technologies deployed in the access network, including other DSL technologies. SHDSL transceivers do not support the use of analogue splitting technology for coexistence with either PO
11、TS or ISDN. Regional requirements, including both operational differences and performance requirements, are specified in Annexes A, B and C. Requirements for signal regenerators are specified in Annex D. Annex E describes application-specific framing modes that may be supported by SHDSL transceivers
12、. See Annex H/G.992.1 1 for specifications of transceivers for use in networks with existing TCM-ISDN service (as specified in Appendix III/G.961, in Bibliography B1). History With respect to the previous version 1 (2001), this version 2 introduces the following additions and modifications: The opti
13、onal four-wire mode has been extended to a more general multi-pair mode which provides optional support for up to four-pair connections. See 7.2.1.5. Note that the integrity of the optional 4-wire mode in revision 1 is preserved. The four-wire mode is identical to M-pair mode with M = 2, except for
14、the method of assigning ordinal numbers to the wire pairs. In four-wire mode, the ordinal numbers (the wire pair identification number) are assigned as described in 6.3, while in M-pair mode the ordinal numbers are assigned to wire pairs as described in 7.2.1.5. The loops and test conditions specifi
15、ed in Annex B have been updated (see B.3.3), and Appendix IV, Tabulation of Annex B Noise Profiles, has been added. Optional extensions, described in Annex F, allow user data rates up to 5696 kbit/s. Deactivation and warm-start, as specified in Annex H, have been added. Support for Dynamic Rate Repa
16、rtitioning has been added to Dual-Bearer mode. See E.10.3. TPS-TC definitions have been added for Packet Transfer Mode (E.11), Synchronous Transfer Mode with a Dedicated Signalling Channel (E.12), and V5 Encapsulated ISDN or POTS (E.13). Source ITU-T Recommendation G.991.2 was approved on 14 Decembe
17、r 2003 by ITU-T Study Group 15 (2001-2004) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. G.991.2 (12/2003) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sec
18、tor (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 ever
19、y 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 purview
20、, 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 volunta
21、ry. 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 the ne
22、gative 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 involve the
23、 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 Recommendat
24、ion, 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 2004 Al
25、l 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.991.2 (12/2003) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions and abbreviations. 2 3.1 Definitions 2 3.2 Abbreviations . 3 4 Reference mode
26、ls 6 4.1 STU-x functional model. 6 4.2 User plane protocol reference model 7 4.3 Application models. 7 5 Transport capacity 8 6 PMD layer functional characteristics 8 6.1 Data mode operation. 8 6.2 PMD activation sequence. 12 6.3 PMD pre-activation sequence. 16 6.4 G.994.1 pre-activation sequence 20
27、 7 PMS-TC layer functional characteristics 23 7.1 Data mode operation. 23 7.2 PMS-TC activation. 28 8 TPS-TC layer functional characteristics. 30 8.1 Payload block data structure. 30 8.2 Data interleaving in M-pair mode. 31 9 Management . 32 9.1 Management reference model 32 9.2 SHDSL performance pr
28、imitives. 33 9.3 SHDSL line related performance parameters. 34 9.4 Performance data storage . 35 9.5 Embedded operations channel 35 10 Clock architecture. 58 10.1 Reference clock architecture 58 10.2 Clock accuracy . 59 10.3 Definitions of clock sources . 60 10.4 Synchronization to clock sources . 6
29、0 11 Electrical characteristics . 60 11.1 Longitudinal balance 61 11.2 Longitudinal output voltage . 62 11.3 Return loss 62 11.4 Transmit power testing. 64 iv ITU-T Rec. G.991.2 (12/2003) Page 11.5 Signal transfer delay. 65 12 Conformance testing. 66 12.1 Micro-interruptions. 66 Annex A Regional req
30、uirements Region 1 67 A.1 Scope 67 A.2 Test loops 67 A.3 Performance Tests 68 A.4 PSD masks 82 A.5 Region-specific functional characteristics 89 Annex B Regional requirements Region 2 96 B.1 Scope 96 B.2 Test loops 96 B.3 Performance testing 99 B.4 PSD masks 117 B.5 Region-specific functional charac
31、teristics 122 Annex C Regional requirements Region 3 125 Annex D Signal regenerator operation 125 D.1 Reference diagram 125 D.2 Start-up procedures. 126 D.3 Symbol rates . 130 D.4 PSD masks 130 Annex E Application-specific TPS-TC framing. 130 E.1 TPS-TC for clear channel data . 130 E.2 TPS-TC for cl
32、ear channel byte-oriented data. 131 E.3 TPS-TC for unaligned DS1 transport. 132 E.4 TPS-TC for aligned DS1/fractional DS1 transport 133 E.5 TPS-TC for European 2048 kbit/s digital unstructured leased line (D2048U) 134 E.6 TPS-TC for unaligned European 2048 kbit/s digital structured leased line (D204
33、8S) 134 E.7 TPS-TC for aligned European 2048 kbit/s digital structured leased line (D2048S) and fractional . 135 E.8 TPS-TC for synchronous ISDN basic access . 136 E.9 TPS-TC for ATM transport 154 E.10 Dual-bearer TPS-TC mode. 161 E.11 TPS-TC for PTM transport. 176 E.12 TPS-TC for STM with a Dedicat
34、ed Signalling Channel (DSC). 182 E.13 TPS-TC for LAPV5 enveloped POTS or ISDN. 184 ITU-T Rec. G.991.2 (12/2003) v Page Annex F Region 1 requirements for payload data rates up to 5696 kbit/s 188 F.1 Scope 188 F.2 Data rate 189 F.3 Mapper 191 F.4 PSD masks 192 F.5 Crosstalk interference requirements.
35、194 F.6 Functional characteristics . 195 Annex G Reserved for Region 2 requirements for data rates between 2320 kbit/s and *max rate* 196 Annex H Deactivation and warm-start procedure. 196 H.1 Deactivation to reduced power mode . 196 H.2 Warm-start activation . 198 Appendix I Test circuit examples .
36、 203 I.1 Example crosstalk injection test circuit 203 I.2 Example coupling circuits for longitudinal balance and longitudinal output voltage . 203 I.3 Return loss test circuit 204 I.4 Transmit PSD/total power measurement test circuit 205 Appendix II Typical characteristics of cables. 205 II.1 Typica
37、l characteristics of cables for Annex B 205 Appendix III Signal regenerator start-up description . 206 III.1 STU-R initiated Start-up. 207 III.2 STU-C initiated start-up . 208 III.3 SRU initiated start-up. 209 III.4 Collisions and retrains 209 III.5 Diagnostic mode activation 210 Appendix IV Tabulat
38、ion of Annex B noise profiles. 210 BIBLIOGRAPHY 223 ITU-T Rec. G.991.2 (12/2003) 1 ITU-T Recommendation G.991.2 Single-pair high-speed digital subscriber line (SHDSL) transceivers 1 Scope This Recommendation describes a transmission method for providing Single-pair High-speed Digital Subscriber Line
39、 (SHDSL) service as a means for data transport in telecommunications access networks. This Recommendation does not specify all the requirements for the implementation of SHDSL transceivers. Rather, it serves only to describe the functionality needed to assure interoperability of equipment from vario
40、us manufacturers. The definitions of physical user interfaces and other implementation-specific characteristics are beyond the scope of this Recommendation. For interrelationships of this Recommendation with other G.99x-series ITU-T Recommendations, see ITU-T Rec. G.995.1 in Biblography B2 (informat
41、ive). The principal characteristics of this Recommendation are as follows: provisions for duplex operation over one (or, optionally, multiple) mixed gauge two-wire twisted metallic pairs; specification of the physical layer functionality, e.g., line codes and forward error correction; specification
42、of the data link layer functionality, e.g., frame synchronization and framing of application, as well as Operations, Administration and Maintenance (OAM) data; provisions for optional use of repeaters for extended reach; provisions for spectral compatibility with other transmission technologies depl
43、oyed in the access network; provisions for regional requirements, including functional differences and performance requirements. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendatio
44、n. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references lis
45、ted below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. 1 ITU-T Recommendation G.992.1 (1999), Asymmetric Digital Subscriber Line (ADSL)
46、transceivers. 2 ITU-T Recommendation G.994.1 (2003), Handshake procedures for digital subscriber line (DSL) transceivers, plus Amendment 1 (2004). 3 ITU-T Recommendation G.997.1 (2003), Physical layer management for digital subscriber line (DSL) transceivers. 4 IETF RFC 1662 (1994), PPP in HDLC-like
47、 Framing. 5 ISO 8601:2000, Data elements and interchange formats Information interchange Representation of dates and times. 2 ITU-T Rec. G.991.2 (12/2003) 6 ITU-T Recommendation G.996.1 (2001), Test procedures for Digital Subscriber Line (DSL) transceivers. 7 IEC 60950 (1999), Information technology
48、 equipment Safety. 8 ITU-T Recommendation I.432.1 (1999), B-ISDN user-network interface Physical layer specification: General characteristics. 9 ETSI EN 300 324-1 (1994), V Interfaces at the digital Local Exchange (LE); V5.1 interface for the support of Access Network (AN); Part 1: V5.1 Interface sp
49、ecification. 10 ETSI EG 201 900-1 V1.1.1 (2001), Services and Protocols for Advanced Networks (SPAN); Narrowband Services over ATM; Loop Emulation Service (LES) using AAL2; Part 1: LES interface specification ATM Forum Specification af-vmoa-0145.000 (2000), modified. 11 Coded Identification of Equipment Entities of the North American Telecommunications System for Information Exchange Revision of T1.213-1990 (R1996), May 2001. 3 Definitions and abbreviations 3.1 Definit
