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 Corrigendum 3 (04/2017) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Access networks Metallic access networks Fast access to subscriber termin
2、als (G.fast) Physical layer specification Corrigendum 3 Recommendation ITU-T G.9701 (2014) Corrigendum 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 ANALO
3、GUE 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 ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES G.400G.449 COORD
4、INATION 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 U
5、SER-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.8999 ACCESS NETWORKS G.9000G.9999 Metallic access networks G.9700G.9799 Optical line systems for local and access networks G.9800G.9
6、899 In premises networks G.9900G.9999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T G.9701 (2014)/Cor.3 (04/2017) i Recommendation ITU-T G.9701 Fast access to subscriber terminals (G.fast) Physical layer specification Corrigendum 3 Summary Recommendation ITU-T G.
7、9701 specifies 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 dist
8、ribution 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 nece
9、ssary functionality 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 s
10、amples. 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 p
11、reviously 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 powe
12、r, support for increased bit loading, Hlog reporting in both directions, and Xlog reporting. Corrigendum 3 (2017) adds several clarifications, and fixes various errors and inconsistencies. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T G.9701 2014-12-05 15 11.1002/1000/1209
13、0 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.9701 (2014) Cor. 3 2017-04-06
14、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.int/11.1002/1000/11830-en. ii
15、Rec. ITU-T G.9701 (2014)/Cor.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 Sector (ITU-T) is a permanent or
16、gan 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 four years, establishes the
17、 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, the necessary standards are
18、 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 voluntary. However, the Recommendati
19、on 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 negative equivalents are used
20、 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 use of a claimed Intellectu
21、al 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 Recommendation, ITU had received notice
22、 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.itu.int/ITU-T/ipr/. ITU 201
23、7 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)/Cor.3 (04/2017) iii Table of Contents Page 1 Scope . 1 2 References . 3 3 Definitions 3 3.1 Terms defined elsewhere 3 3.2 Terms defined
24、 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 requirements 24 6 Profiles 24 6.1 Definitio
25、n 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 41 8 Transport protocol specific transmission
26、 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-TC) sub-layer 61 9.1 Functional reference m
27、odel 61 9.2 DTU scrambler . 64 9.3 DTU encoder 64 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)/Cor.3 (04/2017) Page 9.8 Retransmission function . 82 10 Physical media dependent (PMD) function 90 10.1 PMD functional reference mod
28、el . 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 group . 142 11 Operation and maintenance (O
29、AM) . 142 11.1 OAM functional model . 142 11.2 Management functions and procedures over eoc . 145 11.3 OAM primitives 189 11.4 OAM parameters 192 12 Link activation methods and procedures 217 12.1 Overview 217 12.2 Special operations channel (SOC) 235 12.3 Initialization procedure . 239 12.4 Loop di
30、agnostics mode . 307 13 Online reconfiguration (OLR) 307 13.1 Overview 307 13.2 Eoc-based procedures . 308 13.3 RMC-based procedures 323 13.4 Low power link states . 328 14 Electrical requirements . 346 14.1 Balance . 346 14.2 Differential port impedance 347 Annex A to Annex X . 348 Annex Y Upstream
31、 dynamic resource reports 349 Annex Z Cross-layer traffic monitoring functions and link state control . 351 Z.0 Introduction 351 Z.1 Definition of Terms 351 Z.2 Abbreviations and acronyms 351 Z.3 Reference models . 352 Z.4 Generic traffic monitoring functions 353 Z.5 Generic information flows 355 Z.
32、6 Link state specific functions . 358 Z.7 Link state management and reporting parameters 362 Rec. ITU-T G.9701 (2014)/Cor.3 (04/2017) v Page Appendix I Wiring topologies and reference loops 364 I.1 Wiring topologies . 364 I.2 Reference loops 364 Appendix II Example OLR use cases . 373 II.1 Transmitt
33、er initiated gain adjustment (TIGA) 373 Appendix III Motivation of MTBE accelerated test . 375 Appendix IV . 377 Appendix V Retransmission buffer size and the achievable bit-rate 378 V.1 Case 1: NSYMret+NSYMack+1 Mus 378 V.2 Case 2: NSYMret+NSYMack+1Mus. 379 V.3 Case 3: Lower bound for the achievabl
34、e net data rate 379 V.4 Memory size example . 380 Appendix VI Example applications of discontinuous operation 381 VI.1 Discontinuous operation with vectoring disabled 381 VI.2 Examples of discontinuous operation with vectoring enabled . 382 Appendices VII to YX . 388 Appendix YY Calculation of loop
35、attenuation (LATN) . 389 Bibliography. 390 Rec. ITU-T G.9701 (2014)/Cor.3 (04/2017) 1 Recommendation ITU-T G.9701 Fast access to subscriber terminals (G.fast) Physical layer specification Corrigendum 3 Editorial note: This is a complete-text publication. Modifications introduced by this corrigendum
36、are shown in revision marks relative to Recommendation ITU-T G.9701 (2014) plus Erratum 1, Corrigenda 1 and 2, and Amendments 1 and 2. 1 Scope This Recommendation supports transmission at an aggregate net data rate (the sum of upstream and downstream rates) up to approximately 1 Gbit/s on twisted wi
37、re-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 (POTS). Whilst asymmetric digital subscriber line transceivers 2 (ADSL2) extended bandwidth (AD
38、SL2plus) uses approximately 2 MHz of the spectrum, and very high speed digital subscriber line transceivers 2 (VDSL2) uses up to 30 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 use of far-e
39、nd 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 deployed from fibre-
40、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 diameter, subjec
41、t 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 subset of the all
42、owed 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 profile for in-band spect
43、ral usage of up to 106 MHz at 4dBm maximum transmit power. 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 do ITU-T Recommendations in the ITU-T G.99x se
44、ries, 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
45、) is identified. For reasons of interoperability, equipment may support multiple Recommendations such that it is able to adapt to the operating mode supported by the far-end equipment. It is the intention of this Recommendation to provide, by negotiation during the initialization, U interface compat
46、ibility and interoperability between transceivers complying with this Recommendation, including transceivers that support different combinations of options. The technology specified in this Recommendation provides the following key application features: Best aspects of fibre to the home (FTTH): up t
47、o one gigabit per second aggregate net data rate; 2 Rec. ITU-T G.9701 (2014)/Cor.3 (04/2017) Best aspects of ADSL2: customer self-install and operation in the presence of bridged taps, avoiding operator truck-rolls to the customer premises for installation and activation of the broadband access serv
48、ice; Coexistence with ADSL2 and VDSL2 on adjacent wire-pairs; Low power operation and all functionality necessary to allow transceivers to be deployed as part of reverse powered (and possibly battery operated) network equipment and to adapt to environmental conditions (e.g., temperature); Management
49、 capabilities allowing transceivers to operate in a zero touch deployment, avoiding truck-rolls to the network equipment for installation and activation of new or upgraded broadband access service; Control of the upstream vs downstream transmission time to adapt net data rates to the needs of the business and the residential customers; Vectoring (self-crosstalk cancellation) for increased net data rates on wir
