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.993.2 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (01/2015) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital sections and digital line system Metallic access networks Very high speed digi
2、tal subscriber line transceivers 2 (VDSL2) Recommendation ITU-T G.993.2 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
3、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 COORDINATION OF RADIOTELEPHONY AND LIN
4、E 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 General G.900G.909 Parameters for optical fibre cable systems G.910G.919 Digital sections at
5、 hierarchical bit rates based 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 syst
6、ems for customer access to ISDN G.960G.969 Optical fibre submarine cable systems G.970G.979 Optical line systems for local and access networks G.980G.989 Metallic access networks G.990G.999 MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999 TRANSMISSION MEDIA
7、 CHARACTERISTICS G.6000G.6999 DATA OVER TRANSPORT GENERIC ASPECTS G.7000G.7999 PACKET OVER TRANSPORT ASPECTS G.8000G.8999 ACCESS NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T G.993.2 (01/2015) i Recommendation ITU-T G.993.2 Very high speed d
8、igital subscriber line transceivers 2 (VDSL2) Summary Recommendation ITU-T G.993.2 specifies an access technology that exploits the existing infrastructure of copper wires that were originally deployed for POTS services. It can be deployed from central offices, from fibre-fed cabinets located near c
9、ustomer premises, or within buildings. This Recommendation is an enhancement to ITU T G.993.1 that supports asymmetric and symmetric transmission at a bidirectional net data rate up to 200 Mbit/s on twisted pairs using a bandwidth up to 30 MHz. This version of this Recommendation integrates all the
10、previous amendments and corrigenda with the 2011 version of Recommendation ITU-T G.993.2. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T G.993.2 2006-02-17 15 11.1002/1000/8548 1.1 ITU-T G.993.2 (2006) Cor. 1 2006-12-14 15 11.1002/1000/8992 1.2 ITU-T G.993.2 (2006) Amd. 1 2
11、007-04-06 15 11.1002/1000/8991 1.3 ITU-T G.993.2 (2006) Amd. 1 Cor. 1 2007-07-29 15 11.1002/1000/9164 1.4 ITU-T G.993.2 (2006) Cor. 2 2007-07-29 15 11.1002/1000/9166 1.5 ITU-T G.993.2 (2006) Amd. 2 2008-02-06 15 11.1002/1000/9165 1.6 ITU-T G.993.2 (2006) Amd. 3 2008-08-22 15 11.1002/1000/9387 1.7 IT
12、U-T G.993.2 (2006) Amd. 4 2009-01-13 15 11.1002/1000/9654 1.8 ITU-T G.993.2 (2006) Cor. 3 2009-06-29 15 11.1002/1000/9890 1.9 ITU-T G.993.2 (2006) Amd. 5 2010-04-22 15 11.1002/1000/10413 1.10 ITU-T G.993.2 (2006) Amd. 6 2010-11-29 15 11.1002/1000/11022 1.11 ITU-T G.993.2 (2006) Cor. 4 2011-04-13 15
13、11.1002/1000/11149 1.12 ITU-T G.993.2 (2006) Amd. 7 2011-06-22 15 11.1002/1000/11148 2.0 ITU-T G.993.2 2011-12-16 15 11.1002/1000/11415 2.1 ITU-T G.993.2 (2011) Amd. 1 2012-04-06 15 11.1002/1000/11502 2.2 ITU-T G.993.2 (2011) Cor. 1 2012-06-13 15 11.1002/1000/11642 2.3 ITU-T G.993.2 (2011) Amd. 2 20
14、12-12-07 15 11.1002/1000/11795 2.4 ITU-T G.993.2 (2011) Amd. 3 2013-04-22 15 11.1002/1000/11888 2.5 ITU-T G.993.2 (2011) Amd. 4 2013-08-29 15 11.1002/1000/11992 2.6 ITU-T G.993.2 (2011) Amd. 5 2014-01-13 15 11.1002/1000/12096 2.7 ITU-T G.993.2 (2011) Amd. 6 2015-05-22 15 11.1002/1000/12371 3.0 ITU-T
15、 G.993.2 2015-01-13 15 11.1002/1000/12370 3.1 ITU-T G.993.2 (2015) Amd. 1 2015-11-06 15 11.1002/1000/12563 _ * 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/11.10
16、02/1000/11830-en. ii Rec. ITU-T G.993.2 (01/2015) 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 per
17、manent 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 four years, establ
18、ishes 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, the necessary stan
19、dards 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 voluntary. However, the Rec
20、ommendation 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
21、 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 use of a claimed I
22、ntellectual 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 receiv
23、ed 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.itu.int/ITU-T/ipr/
24、. ITU 2016 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.993.2 (01/2015) iii Table of Contents Page 1 Scope . 1 2 References . 3 3 Definitions 4 4 Abbreviations and acronyms 8 5 Reference models
25、11 5.1 VTU functional model 11 5.2 User plane protocol reference model 13 5.3 Management plane reference model . 14 5.4 Application reference models . 15 6 Profiles 19 6.1 Definition 19 6.2 Profile parameter definitions 23 6.3 Profile compliance 26 7 Transmission medium interface characteristics 27
26、7.1 Duplexing method and band plan construction 27 7.2 Power spectral density (PSD) . 28 7.3 Termination impedance 44 7.4 Longitudinal conversion loss 44 8 Transport protocol specific transmission convergence (TPS-TC) function . 45 8.1 The user data TPS-TC 45 8.2 Management TPS-TC (MPS-TC) . 47 8.3
27、Network timing reference TPS-TC (NTR-TC) 51 8.4 Time-of-day TPS-TC (ToD-TC) 52 9 Physical media specific transmission convergence (PMS-TC) sublayer . 59 9.1 PMS-TC functional model . 59 9.2 Scrambler 63 9.3 Forward error correction . 63 9.4 Interleaving . 64 9.5 Framing . 66 9.6 Impulse noise protec
28、tion (INPp) . 75 9.7 Delay . 76 9.8 Bit error ratio (BER) . 77 9.9 Delay variation . 77 10 Physical media dependent (PMD) function 77 10.1 PMD functional model . 77 10.2 DMT superframe 78 10.3 Symbol encoder for data symbols 79 iv Rec. ITU-T G.993.2 (01/2015) Page 10.4 Modulation . 93 10.5 Symbol en
29、coder for sync symbol . 97 10.6 Symbol encoder for initialization . 97 11 Operation and maintenance (OAM) . 98 11.1 OAM functional model . 98 11.2 VDSL2 management entity (VME) 100 11.3 OAM primitives 135 11.4 OAM parameters 138 11.5 Data gathering function 173 12 Link activation methods and procedu
30、res 185 12.1 Overview 185 12.2 Special operations channel (SOC) 193 12.3 Initialization procedure . 197 12.4 Loop diagnostic mode procedures 287 12.5 Fast start-up 296 13 On-line reconfiguration (OLR) . 296 13.1 Types of on-line reconfiguration 296 13.2 Control parameters . 297 13.3 Timing of change
31、s in subcarrier configuration 299 13.4 Receiver initiated procedure . 301 14 Electrical requirements . 304 14.1 Termination impedance model . 304 14.2 Service splitters 304 Annex A Region A (North America) 306 A.1 Band plan 306 A.2 Limit PSD masks 306 A.3 UPBO reference PSDs 314 Annex B Region B (Eu
32、rope) . 315 B.1 Band plans 315 B.2 Limit PSD mask options . 318 B.3 UPBO reference PSDs 334 B.4 Template PSD . 334 B.5 Compliance . 334 Annex C Region C (Japan) . 335 C.1 Band plan 335 C.2 Limit PSD masks 335 C.3 VDSL2 system with PSD reduction at frequencies below DPBOFMAX 344 C.4 Upstream power ba
33、ck-off (UPBO) PSD masks . 344 C.5 Service Splitter . 345 Rec. ITU-T G.993.2 (01/2015) v Page C.6 Test loops and crosstalk disturbers . 345 Annex D 347 Annex E 347 Annex F 347 Annex G 347 Annex H 347 Annex J 347 Annex K 347 Annex L TPS-TC functional descriptions . 348 L.1 STM transmission convergence
34、 (STM-TC) function . 348 L.2 ATM transmission convergence (ATM-TC) function . 354 L.3 Packet transmission convergence function (PTM-TC) 365 Annex M Time-of-day distribution over VDSL2 links 370 M.1 Time-of-day distribution operational overview 370 M.2 Definitions 370 M.3 Abbreviations . 370 M.4 VTU
35、functional model 370 M.5 TPS-TC function 370 M.6 eoc communication protocol 370 M.7 ToD TPS-TC (ToD-TC) . 370 M.8 Mapping of OH data . 370 M.9 eoc transmission protocol . 370 M.10 Frequency synchronization command 370 M.11 Time synchronization command and responses . 372 M.12 Updates to initializati
36、on 372 Annex N Region D (China) 373 N.1 Band plans 373 N.2 Limit PSD mask options . 375 Annex O 380 Annex P Short reach VDSL2 with reduced power and enhanced data rate 381 P.1 Scope 381 P.2 Reduced ATP 381 P.3 Minimum bidirectional net data rate capability 381 P.4 ITU-T G.998.4 Annex D support for e
37、nhanced net data rates with ITU-T G.998.4 . 381 P.5 SRA support . 382 P.6 TPS-TC . 382 Annex Q Enhanced data rate 35 MHz VDSL2 with 4.3125 kHz subcarrier spacing . 383 vi Rec. ITU-T G.993.2 (01/2015) Page Q.1 Scope 383 Q.2 Capabilities related to the profile . 383 Q.3 ITU-T G.998.4 Annex D support f
38、or enhanced net data rates . 384 Q.4 SRA support . 385 Q.5 TPS-TC . 386 Q.6 Additional changes to ITU-T G.993.2 for operation according to profile 35b 386 Annex R 400 Annex S 400 Annex T 400 Annex U 400 Annex V 400 Annex W 400 Annex X ITU-T G.993.5-friendly ITU-T G.993.2 operation in the downstream
39、direction 401 X.1 Power management commands and responses (clause 11.2.3.9) . 401 X.2 Initialization procedure (supplements clause 12.3) 402 Annex Y Full ITU-T G.993.5-friendly ITU-T G.993.2 operation 409 Y.1 Initialization procedure (supplements clause 12.3) 409 Y.2 R-MSG1 (supplements clause 10.3.
40、2.2 of ITU-T G.993.5) 412 Y.3 O-TA_UPDATE (supplements clause 10.4.2.1 of ITU-T G.993.5) 412 Y.4 R-P-VECTOR 2 (replaces clause 10.4.4.5 of ITU-T G.993.5) . 412 Y.5 O-PMS (supplements clause 10.5.2.1 of ITU-T G.993.5) . 413 Y.6 eoc messages for backchannel configuration (replaces clause 8.1 of ITU-T
41、G.993.5) 413 Y.7 Loop diagnostic mode procedures (replaces clause 12.4) 413 Appendix I Example values of DPBO parameters to protect ADSL2plus for clause C.3 414 I.1 Example PSD parameters . 414 I.2 Example Cable parameters . 414 I.3 Example frequency parameters 415 Appendix II Impact of loop and VTU
42、 impedance mismatch on the Hlog accuracy . 416 Bibliography. 419 Rec. ITU-T G.993.2 (01/2015) 1 Recommendation ITU-T G.993.2 Very high speed digital subscriber line transceivers 2 (VDSL2) 1 Scope This Recommendation is an enhancement to ITU-T G.993.1 that supports transmission at a bidirectional net
43、 data rate (the sum of upstream and downstream rates) up to 200 Mbit/s on twisted pairs. This Recommendation is an access technology that exploits the existing infrastructure of copper wires that were originally deployed for POTS (plain old telephone service). This Recommendation specifies only disc
44、rete multi-tone (DMT) modulation and incorporates components from ITU-T G.993.1 (VDSL), ITU-T G.992.3 (ADSL2), and ITU-T G.992.5 (ADSL2 plus). Whilst POTS uses approximately the lowest 4 kHz and ADSL uses approximately 2 MHz of the copper wire spectrum, this Recommendation is defined to allow the us
45、e of up to 30 MHz of the spectrum. This Recommendation can be deployed from central offices, from fibre-fed cabinets located near the customer premises, or within buildings. The availability of bandwidth up to 30 MHz allows ITU-T G.993.2 transceivers to provide reliable high data rate operation on s
46、hort loops. Without the use of the US0 band, this Recommendation should operate reliably over loop lengths that are similar to those of ITU-T G.993.1, or slightly longer lengths due to the mandatory support of trellis coding. The addition of the US0 band and means to train echo cancellers and time-d
47、omain equalizers (TEQs) also allows this Recommendation to provide reliable operation on loops up to approximately 2 500 metres of 26 AWG (0.4 mm). This Recommendation defines a wide range of settings for various parameters (such as bandwidth and transmitter power) that could potentially be supporte
48、d by a transceiver. Therefore, this Recommendation specifies profiles to allow transceivers to support a subset of the allowed settings and still be compliant with the Recommendation. The specification of multiple profiles allows vendors to limit implementation complexity and develop implementations
49、 that target specific service requirements. Some profiles are better suited for asymmetric data rate services, whereas other profiles are better for symmetric data rate services. The annexes of this Recommendation include band plans and power spectral density (PSD) masks that address region-specific requirements. Like ITU-T G.993.1, this Recommendation defines upstream power back-off (UPBO) to mitigate far-end
