1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T G.9701 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 3 (04/2017) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Access networks Metallic access networks Fast access to subscriber terminal
2、s (G.fast) Physical layer specification Amendment 3 Recommendation ITU-T G.9701 (2014) Amendment 3 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 CA
3、RRIER-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 ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES G.400G.449 COORDINATIO
4、N OF RADIOTELEPHONY AND LINE TELEPHONY G.450G.499 TRANSMISSION MEDIA AND OPTICAL SYSTEMS CHARACTERISTICS G.600G.699 DIGITAL TERMINAL EQUIPMENTS G.700G.799 DIGITAL NETWORKS G.800G.899 DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900G.999 MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RE
5、LATED ASPECTS G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DATA OVER TRANSPORT GENERIC ASPECTS G.7000G.7999 PACKET OVER TRANSPORT ASPECTS G.8000G.8999 ACCESS NETWORKS G.9000G.9999 Metallic access networks G.9700G.9799 Optical line systems for local and access networks G.9800G.9899 In
6、 premises networks G.9900G.9999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T G.9701 (2014)/Amd.3 (04/2017) i Recommendation ITU-T G.9701 Fast access to subscriber terminals (G.fast) Physical layer specification Amendment 3 Summary Recommendation ITU-T G.9701 spe
7、cifies a gigabit broadband access technology that exploits the existing infrastructure of wire-pairs that were originally deployed for plain old telephone service (POTS) services. Equipment implementing this Recommendation can be deployed from fibre-fed distribution points (fibre to the distribution
8、 point, FTTdp) located very near the customer premises, or within buildings (fibre to the building, FTTB). This Recommendation supports asymmetric and symmetric transmission at an aggregate net data rate up to 1 Gbit/s on twisted wire-pairs using spectrum up to 106 MHz and specifies all necessary fu
9、nctionality to support far-end crosstalk (FEXT) cancellation between multiple wire-pairs, and facilitates low power operation. Corrigendum 1 (2015) provides clarifications and corrects various errors in the Recommendation, and in particular includes a change to the definition of DFT output samples.
10、Corrigendum 2 (2016) increases the number of RFI bands from 16 to 32, and provides clarifying text on alignment between TIGA and SRA/FRA procedures, tone repetition, unavailable seconds, and byte order in SOC and eoc messages. Amendment 1 (2016) specifies test parameters, some of which had previousl
11、y been left for further study, and specifies support for low power operation. Amendment 2 (2016) includes a new annex on cross-layer traffic monitoring functions and link state control to support low power operation. It also includes a new 106 MHz profile with increased maximum transmit power, suppo
12、rt for increased bit loading, Hlog reporting in both directions, and Xlog reporting. Corrigendum 3 (2017) adds several clarifications, and fixes various errors and inconsistencies. Amendment 3 adds support for new functionality: full specification of the 212 MHz profile, Annex X Operation without mu
13、lti-line coordination intended for a crosstalk free environment (e.g., coaxial cable medium) including dynamic time assignment (DTA), Annex T higher layer control aspects of DTA, and Annex S software download to NTs. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T G.9701 201
14、4-12-05 15 11.1002/1000/12090 1.1 ITU-T G.9701 (2014) Cor. 1 2015-11-22 15 11.1002/1000/12541 1.2 ITU-T G.9701 (2014) Cor. 2 2016-05-07 15 11.1002/1000/12817 1.3 ITU-T G.9701 (2014) Amd. 1 2016-05-07 15 11.1002/1000/12542 1.4 ITU-T G.9701 (2014) Amd. 2 2016-07-22 15 11.1002/1000/12816 1.5 ITU-T G.97
15、01 (2014) Cor. 3 2017-04-06 15 11.1002/1000/13069 1.6 ITU-T G.9701 (2014) Amd. 3 2017-04-06 15 11.1002/1000/13068 _ * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.in
16、t/11.1002/1000/11830-en. ii Rec. ITU-T G.9701 (2014)/Amd.3 (04/2017) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sect
17、or (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 every
18、 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,
19、 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 voluntar
20、y. 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 n
21、egative 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 RIGHTSITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the
22、 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
23、ion, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www
24、.itu.int/ITU-T/ipr/. ITU 2017 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T G.9701 (2014)/Amd.3 (04/2017) iii Table of Contents Page Amendment 3 . i 1 Scope . 1 2 References . 3 3 Definitions 3 3.1
25、 Terms defined elsewhere 3 3.2 Terms defined in this Recommendation . 3 4 Abbreviations and acronyms 7 5 Reference models and system requirements . 11 5.1 System reference models 11 5.2 Application reference models . 15 5.3 FTU protocol reference model . 20 5.4 FTU functional model 22 5.5 INP system
26、 requirements 24 6 Profiles 24 6.1 Definition 24 6.2 Profile compliance 26 7 Transmission medium interface characteristics 27 7.1 Duplexing method 27 7.2 Frequency band 27 7.3 Power spectral density 27 7.4 Out-of-band PSD limit . 41 7.5 Termination impedance 41 7.6 Maximum aggregate transmit power 4
27、1 8 Transport protocol specific transmission convergence (TPS-TC) function . 41 8.1 Functional reference model 41 8.2 Generic DTU format . 50 8.3 Packet-based TPS-TC (PTM-TC) 52 8.4 Network timing reference (NTR) . 55 8.5 Time-of-day (ToD) . 57 9 Physical media specific transmission convergence (PMS
28、-TC) sub-layer 61 9.1 Functional reference model 61 9.2 DTU scrambler . 64 9.3 DTU encoder 65 9.4 Interleaver . 65 9.5 Data frame multiplexer . 66 9.6 RMC . 69 9.7 Acknowledgement 80 iv Rec. ITU-T G.9701 (2014)/Amd.3 (04/2017) Page 9.8 Retransmission function . 82 10 Physical media dependent (PMD) f
29、unction 90 10.1 PMD functional reference model . 90 10.2 Symbol encoder 94 10.3 Precoder (downstream vectoring) . 116 10.4 Modulation . 130 10.5 TDD frame structure . 133 10.6 Superframe structure 136 10.7 Normal and discontinuous operation intervals . 137 10.8 Alignment of transmissions in vectored
30、 group . 142 11 Operation and maintenance (OAM) . 142 11.1 OAM functional model . 142 11.2 Management functions and procedures over eoc . 146 11.3 OAM primitives 190 11.4 OAM parameters 193 12 Link activation methods and procedures 219 12.1 Overview 219 12.2 Special operations channel (SOC) 236 12.3
31、 Initialization procedure . 240 12.4 Loop diagnostics mode . 309 13 Online reconfiguration (OLR) 309 13.1 Overview 309 13.2 Eoc-based procedures . 310 13.3 RMC-based procedures 326 13.4 Low power link states . 331 14 Electrical requirements . 349 14.1 Balance . 349 14.2 Differential port impedance 3
32、50 Annex A to Annex R 351 Annex S NT software upgrade 352 S.1 Scope 352 S.2 References 352 S.3 Reference model . 352 S.4 Software image management process 353 S.5 Message set . 358 S.6 Software upgrade (informative) . 369 Annex T Dynamic time assignment (DTA) higher-layer control aspects . 375 T.1 S
33、cope 375 T.2 DTA control parameters . 375 Rec. ITU-T G.9701 (2014)/Amd.3 (04/2017) v Page T.3 Coordination between the link state request and the DTA request 377 Annex U to Annex W. 378 Annex X Operation without multi-line coordination intended for a crosstalk-free environment 379 X.1 Scope 379 X.2
34、Definitions 379 X.3 Abbreviations and acronyms 379 X.4 Reference model(s) . 379 X.5 Profiles 380 X.6 Dynamic time assignment (DTA) 382 X.7 Initialization messages 389 X.8 Discontinuous operation . 393 X.9 On-line reconfiguration 393 X.10 Initialization 393 X.11 Low power states 393 X.12 Adaptation t
35、o the coaxial cable medium 393 Annex Y Upstream dynamic resource reports . 399 Annex Z Cross-layer traffic monitoring functions and link state control 401 Z.0 Introduction 401 Z.1 Definition of Terms 401 Z.2 Abbreviations and acronyms 401 Z.3 Reference models . 402 Z.4 Generic traffic monitoring fun
36、ctions 403 Z.5 Generic information flows 405 Z.6 Link state specific functions . 408 Z.7 Link state management and reporting parameters 412 Appendix I Wiring topologies and reference loops 414 I.1 Wiring topologies . 414 I.2 Reference loops 414 Appendix II Example OLR use cases . 423 II.1 Transmitte
37、r initiated gain adjustment (TIGA) 423 Appendix III Motivation of MTBE accelerated test . 425 Appendix IV . 427 Appendix V Retransmission buffer size and the achievable bit-rate 428 V.1 Case 1: NSYMret+NSYMack+1 Mus 428 V.2 Case 2: NSYMret+NSYMack+1Mus. 429 V.3 Case 3: Lower bound for the achievable
38、 net data rate 429 V.4 Memory size example . 430 Appendix VI Example applications of discontinuous operation 431 vi Rec. ITU-T G.9701 (2014)/Amd.3 (04/2017) Page VI.1 Discontinuous operation with vectoring disabled 431 VI.2 Examples of discontinuous operation with vectoring enabled . 432 Appendices
39、VII to YX . 438 Appendix YY Calculation of loop attenuation (LATN) 439 Bibliography. 440 Rec. ITU-T G.9701 (2014)/Amd.3 (04/2017) 1 Recommendation ITU-T G.9701 Fast access to subscriber terminals (G.fast) Physical layer specification Amendment 3 Editorial note: This is a complete-text publication. E
40、xcept for new Annexes S, T and X, modifications introduced by this amendment are shown in revision marks relative to Recommendation ITU-T G.9701 (2014) plus Erratum 1, Corrigenda 1, 2 and 3, Amendments 1 and 2 and Cor.1 Erratum 1. 1 Scope This Recommendation supports transmission at an aggregate net
41、 data rate (the sum of upstream and downstream rates) up to approximately 1 Gbit/s on twisted wire-pairs. This Recommendation specifies the operation of a broadband access technology that exploits the existing infrastructure of wire-pairs that were originally deployed for plain old telephone service
42、 (POTS). and, with Amendment 3, adds support for operation over coaxial cables. This Recommendation supports transmission at an aggregate net data rate (the sum of upstream and downstream rates) up to approximately 2 Gbit/s. Whilst asymmetric digital subscriber line transceivers 2 (ADSL2) extended b
43、andwidth (ADSL2plus) uses approximately 2 MHz of the spectrum, and very high speed digital subscriber line transceivers 2 (VDSL2) uses up to 350 MHz of the spectrum, this Recommendation defines profiles using spectrum up to 106 MHz and 212 MHz and specifies all necessary functionality to support the
44、 use of far-end crosstalk (FEXT) cancellation between ITU-T G.9701 transceivers deployed on multiple wire-pairs. The availability of spectrum up to 106 MHz or 212 MHz allows ITU-T G.9701 transceivers to provide reliable high data rate operation on very short loops. This Recommendation can be deploye
45、d from fibre-fed distribution points located very near the customer premises, or within the buildings. This Recommendation is optimized to operate over wire-pairs up to approximately 250 m of 0.5 mm diameter. However, it is capable of operation over wire-pairs up to at least 400 meters of 0.5 mm dia
46、meter, subject to some performance limitations. This Recommendation defines a wide range of settings for various parameters (such as spectral usage and transmitter power) that may be supported by a transceiver. Therefore, this Recommendation specifies profiles to allow transceivers to support a subs
47、et of the allowed settings and still be compliant with the Recommendation. The specification of multiple profiles allows vendors to limit the implementation complexity and develop implementations that target specific service requirements. This edition of the Recommendation specifies the transmission
48、 profiles for in-band spectral usage of up to 106212 MHz at 4dBmand maximum transmit power up to +8 dBm. A second profile for in-band spectral usage up to 212 MHz is for further study. This Recommendation operates in compliance with the power spectral density (PSD) specification in ITU-T G.9700. As
49、do ITU-T Recommendations in the ITU-T G.99x series, this Recommendation uses ITU-T G.994.1 to initiate the transceiver training sequence. Through negotiation during the handshake phase of the initialization, the capability of equipment to support this Recommendation and/or ITU-T G.99x series Recommendations (e.g., b-ITU-T G.993.2 defining VDSL2) is identified. For reasons of interoperability, equipment may supp
