1、 International Telecommunication Union ITU-T G.992.3TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (04/2009) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital sections and digital line system Access networks Asymmetric digital subscriber line transceivers 2 (ADSL2) Reco
2、mmendation ITU-T G.992.3 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 CARRIER-TRANSMISSION SYSTEMS G.200G.299 INDIVIDUAL CHARACTERISTICS OF INTERN
3、ATIONAL 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 TRANSMISSION MEDIA AND O
4、PTICAL 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 hierarchical bit rates based on a bit rate of
5、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 ISDN G.960G.969 Opti
6、cal fibre submarine cable systems G.970G.979 Optical line systems for local and access networks G.980G.989 Access networks G.990G.999MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DATA OVER TRANSPORT GENERIC
7、 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.992.3 (04/2009) i Recommendation ITU-T G.992.3 Asymmetric digital subscriber line transceivers 2 (ADSL2) Summary Recommen
8、dation ITU-T G.992.3 describes asymmetric digital subscriber line (ADSL) transceivers on a metallic twisted pair that allows high-speed data transmission between the network operator end (ATU-C) and the customer end (ATU-R). It defines a variety of frame bearers in conjunction with one of two other
9、services, or without underlying service, dependent on the environment: 1) ADSL transmission simultaneously on the same pair with voiceband service. 2) ADSL transmission simultaneously on the same pair with integrated services digital network (ISDN) (Appendix I or II of Recommendation ITU-T G.961) se
10、rvices. 3) ADSL transmission without underlying service, optimized for deployment with ADSL over voiceband service in the same binder cable. 4) ADSL transmission without underlying service, optimized for deployment with ADSL over ISDN service in the same binder cable. 5) ADSL transmission with speci
11、fic requirements for Reach Extended ADSL2, simultaneously on the same pair with voiceband service. 6) ADSL transmission with extended upstream bandwidth, simultaneously on the same pair with voiceband service. 7) ADSL transmission on the same pair with voiceband services and operating in an environm
12、ent with TCM-ISDN (Appendix III of Recommendation ITU-T G.961) services in an adjacent pair. This Recommendation specifies the physical layer characteristics of the asymmetric digital subscriber line (ADSL) interface to metallic loops. This Recommendation has been written to help ensure the proper i
13、nterfacing and interworking of ADSL transmission units at the customer end (ATU-R) and at the network operator end (ATU-C), and also to define the transport capability of the units. Proper operation shall be ensured when these two units are manufactured and provided independently. A single twisted p
14、air of telephone wires is used to connect the ATU-C to the ATU-R. The ADSL transmission units must deal with a variety of wire pair characteristics and typical impairments (e.g., crosstalk and noise). An ADSL transmission unit can simultaneously convey all of the following: a number of downstream fr
15、ame bearers; a number of upstream frame bearers; a baseband plain old telephone service (POTS)/ISDN duplex channel; and ADSL line overhead for framing, error control, operations, and maintenance. Systems support a net data rate ranging up to a minimum of 8 Mbit/s downstream and 800 kbit/s upstream.
16、Support of net data rates above 8 Mbit/s downstream and support of net data rates above 800 kbit/s upstream are optional. This Recommendation defines several optional capabilities and features: transport of STM and/or ATM and/or Packets; transport of a network timing reference; multiple latency path
17、s; multiple frame bearers; ii Rec. ITU-T G.992.3 (04/2009) short initialization procedure; dynamic rate repartitioning; seamless rate adaptation; extended impulse noise protection; erasure decoding; virtual noise; impulse noise monitor. It is the intention of this Recommendation to provide, by negot
18、iation during initialization, for U-interface compatibility and interoperability between transceivers complying with this Recommendation and between transceivers that include different combinations of options. This Recommendation describes the second generation of ADSL, based on the first generation
19、 Recommendation ITU-T G.992.1. It is intended that this Recommendation be implemented in multi-mode devices that support both Recommendations ITU-T G.992.3 and ITU-T G.992.1. This Recommendation has been written to provide additional features, relative to Recommendation ITU-T G.992.1. Recommendation
20、 ITU-T G.992.1 was approved in 1999. Since then, several potential improvements have been identified in areas such as data rate versus loop reach performance, loop diagnostics, deployment from remote cabinets, spectrum control, power control, robustness against loop impairments and radio frequency i
21、nterference (RFI), and operations and maintenance. This Recommendation provides a new ADSL U-interface specification, including the identified improvements, which ITU-T believes will be most helpful to the ADSL industry. Relative to Recommendation ITU-T G.992.1, the following application-related fea
22、tures have been added: Improved application support for an all-digital mode of operation and voice-over-ADSL operation. Packet TPS-TC function, in addition to the existing STM and ATM TPS-TC functions. Mandatory support of 8 Mbit/s downstream and 800 kbit/s upstream for TPS-TC function #0 and frame
23、bearer #0. Support for inverse multiplexing over ATM (IMA) in the ATM TPS-TC. Improved configuration capability for each TPS-TC with configuration of latency, bit error ratio (BER) and minimum, maximum and reserved data rates. Relative to Recommendation ITU-T G.992.1, the following PMS-TC-related fe
24、atures have been added: A more flexible framing, including support for up to 4 frame bearers, 4 latency paths. Parameters allowing enhanced configuration of the overhead channel. Frame structure with receiver-selected coding parameters. Frame structure with optimized use of Reed-Solomon (RS) coding
25、gain. Frame structure with configurable latency and bit error ratio. Operations, administration and management (OAM) protocol to retrieve more detailed performance monitoring information. Enhanced on-line reconfiguration capabilities, including dynamic rate repartitioning. Relative to Recommendation
26、 ITU-T G.992.1, the following PMD-related features have been added: New line diagnostics procedures available for both successful and unsuccessful initialization scenarios, loop characterization and trouble-shooting. Enhanced on-line reconfiguration capabilities including bitswaps and seamless rate
27、Rec. ITU-T G.992.3 (04/2009) iii adaptation. Optional short initialization sequence for recovery from errors or fast resumption of operation. Optional seamless rate adaptation with line rate changes during showtime. Improved robustness against bridged taps with receiver-determined pilot tone. Improv
28、ed transceiver training with exchange of detailed transmit signal characteristics. Improved SNR measurement during channel analysis. Subcarrier blackout to allow RFI measurement during initialization and showtime. Improved performance with mandatory support of trellis coding. Improved performance wi
29、th mandatory one-bit constellations. Improved performance with data modulated on the pilot tone. Improved RFI robustness with receiver-determined tone ordering. Improved transmit power cutback possibilities at both the central office (CO) and remote side. Improved initialization with receiver- and t
30、ransmitter-controlled duration of initialization states. Improved initialization with receiver-determined carriers for modulation of messages. Improved channel identification capability with spectral shaping during channel discovery and transceiver training. Mandatory transmit power reduction to min
31、imize excess margin under management layer control. Power saving feature for the central office ATU with new L2 low power state. Power saving feature with new L3 idle state. Spectrum control with individual tone masking under operator control through the CO-MIB. Improved conformance testing, includi
32、ng increase in data rates for many existing tests. Through negotiation during initialization, the capability of equipment to support this Recommendation and/or Recommendation ITU-T G.992.1 is identified. For reasons of interoperability, equipment may support both Recommendations such that it is able
33、 to adapt to the operating mode supported by the far-end equipment. Annex C to this Recommendation has been published independently due to its size and its specific structure. Source Recommendation ITU-T G.992.3 was approved on 22 April 2009 by ITU-T Study Group 15 (2009-2012) under Recommendation I
34、TU-T A.8 procedures. iv Rec. ITU-T G.992.3 (04/2009) 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
35、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 four years, est
36、ablishes 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 s
37、tandards 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
38、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 negative equivalen
39、ts 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 use of a claime
40、d 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 Recommendation, ITU had rec
41、eived 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/i
42、pr/. ITU 2010 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.992.3 (04/2009) v CONTENTS Page 1 Scope 1 2 References. 2 3 Definitions 3 4 Abbreviations and acronyms 6 5 Reference models 9 5.1 ATU f
43、unctional model 9 5.2 User plane protocol reference model 11 5.3 Management plane reference model . 12 5.4 Application models . 12 6 Transport protocol-specific transmission convergence (TPS-TC) function . 17 6.1 Transport capabilities . 17 6.2 Interface signals and primitives 17 6.3 Control paramet
44、ers . 19 6.4 Data plane procedures 19 6.5 Management plane procedures . 20 6.6 Initialization procedure . 20 6.7 On-line reconfiguration 21 6.8 Power management mode . 21 7 Physical media-specific transmission convergence (PMS-TC) function . 22 7.1 Transport capabilities . 22 7.2 Additional function
45、s . 24 7.3 Block interface signals and primitives . 24 7.4 Block diagram and internal reference point signals . 27 7.5 Control parameters . 29 7.6 Frame structure . 30 7.7 Data plane procedures 37 7.8 Control plane procedures 41 7.9 Management plane procedures . 48 7.10 Initialization procedures . 4
46、9 7.11 On-line reconfiguration 61 7.12 Power management mode . 62 8 Physical media-dependent function 63 8.1 Transport capabilities . 63 8.2 Additional functions . 65 8.3 Block interface signals and primitives . 65 8.4 Block diagram and internal reference point signals . 67 8.5 Control parameters .
47、69 vi Rec. ITU-T G.992.3 (04/2009) Page 8.6 Constellation encoder for data symbols . 80 8.7 Constellation encoder for synchronization and L2 exit symbols . 94 8.8 Modulation . 97 8.9 Transmitter dynamic range . 100 8.10 Transmitter spectral masks . 101 8.11 Control plane procedures 102 8.12 Manageme
48、nt plane procedures . 102 8.13 Initialization procedures . 121 8.14 Short initialization procedures 166 8.15 Loop diagnostics mode procedures 170 8.16 On-line reconfiguration of the PMD function 185 8.17 Power management in the PMD function 187 9 Management protocol-specific transmission convergence
49、 (MPS-TC) functions . 188 9.1 Transport functions . 189 9.2 Additional functions . 189 9.3 Block interface signals and primitives . 190 9.4 Management plane procedures . 192 9.5 Power management 215 10 Dynamic behaviour . 221 10.1 Initialization 221 10.2 On-line reconfiguration (OLR) . 221 10.3 Power management 224 Annex A Specific requirements for an ADSL system operating in the frequency band above POTS 227 A.1 ATU-C functional characteristics (pert
