1、 International Telecommunication Union ITU-T G.992.5TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (01/2009) 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) Exte
2、nded bandwidth (ADSL2plus) Recommendation ITU-T G.992.5 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 INDIV
3、IDUAL 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 LINE TELEPHONY G.45
4、0G.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 hierarchical bi
5、t 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 systems for customer
6、 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 Access networks G.990G.999QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DATA OV
7、ER 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.992.5 (01/2009) i Recommendation ITU-T G.992.5 Asymmetric digital subscriber line transceivers 2 (ADS
8、L2) Extended bandwidth (ADSL2plus) Summary Recommendation ITU-T G.992.5 describes asymmetrical 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), using extended bandwid
9、th. This Recommendation defines a variety of frame bearers in conjunction with one of two other 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 wit
10、h integrated services digital network (ISDN) (see Appendix I or II or Recommendation ITU-T G.961) services. 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
11、for deployment with ADSL over ISDN service in the same binder cable. 5) ADSL transmission with extended upstream bandwidth, simultaneously on the same pair with voice band service. ADSL transmission on the same pair with voiceband services and operating in an environment with TCM-ISDN (see Appendix
12、III of Recommendation ITU-T G.961) services in an adjacent pair is for further study. This Recommendation specifies the physical layer characteristics of the extended bandwidth asymmetric digital subscriber line (ADSL) interface to metallic loops. As compared to the ADSL2 transceiver defined in Reco
13、mmendation ITU-T G.992.3, the operating modes use double the downstream bandwidth. When operating on the same pair with voiceband services, an additional operating mode is defined, using the double upstream bandwidth. This Recommendation has been written to help ensure the proper interfacing and int
14、erworking 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 pair of telephone wi
15、res 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 extended bandwidth ADSL transmission unit (ADSL2plus transceiver) can simultaneously convey all of the following: a
16、 number of downstream frame 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 16 Mbit/s downstream a
17、nd 800 kbit/s upstream. Support of net data rates above 16 Mbit/s downstream and support of net data rates above 800 kbit/s upstream are optional. This Recommendation includes mandatory requirements, recommendations and options; these are designated by the words shall“, “should“ and “may“, respectiv
18、ely. The word “will“ is used only to designate events that take place under some defined set of circumstances. This Recommendation is written as a delta Recommendation relative to Recommendation ITU-T Rec. G.992.3. For the clauses which have been changed, this Recommendation contains complete replac
19、ement text (unless explicitly indicated). For the clauses which have not been changed, this Recommendation contains only the clause heading, with reference to Recommendation ITU-T G.992.3. This Recommendation defines several optional capabilities and features: transport of STM and/or ATM and/or Pack
20、ets; transport of a network timing reference; multiple latency paths; ii Rec. ITU-T G.992.5 (01/2009) multiple frame bearers; short initialization procedure; dynamic rate repartitioning; seamless rate adaptation; - extended impulse noise protection; - erasure decoding; - virtual noise; - impulse noi
21、se monitor. It is the intention of this Recommendation to provide, by negotiation during initialization, for U-interface compatibility and interoperability between transceivers complying with this Recommendation, and between transceivers that include different combinations of options. Annex C to thi
22、s Recommendation has been published independently due to its size and its specific structure. History This Recommendation describes extended bandwidth ADSL2 (ADSL2plus) transceivers, as a delta to the second generation ADSL (ADSL2 Recommendation ITU-T G.992.3). This Recommendation has been written t
23、o provide additional features relative to Recommendation ITU-T G.992.3, which was approved on 22 April 2009. Several potential improvements have been identified to better address higher data rates for shorter loops and longer reach for high data rates. This Recommendation provides a new ADSL U-inter
24、face specification, including the identified improvements, which ITU-T believes will be most helpful to the ADSL industry. Relative to Recommendation ITU-T G.992.3, the following application-related feature has been added: Improved support for services requiring high downstream data rates (e.g., bro
25、adband entertainment services). Relative to Recommendation ITU-T G.992.3, the following PMS-TC-related feature has been added: Support of up to 16 Reed-Solomon codewords per symbol; Relative to Recommendation ITU-T G.992.3, the following PMD-related features have been added: Extended downstream band
26、width to 2.208 MHz (512 subcarriers) for all operation modes (POTS/ISDN/all-digital mode); Downstream spectrum control with individual maximum transmit PSD at U-C reference point per subcarrier, under operator control through CO-MIB, allows configuration per the regional requirements (e.g., North Am
27、erica, Europe or Japan) and deployment scenarios (e.g., central office or remote). Downstream spectrum shaping during showtime (shaped transmit PSD in the passband, i.e., non-flat) for improved downstream transmit PSD flexibility. Through negotiation during initialization, the capability of equipmen
28、t to support this and other ITU-T G.992.x-series ADSL Recommendations is identified. For reasons of interoperability, equipment may choose to support multiple Recommendations, such that it is able to adapt to the operating mode supported by the far-end equipment. Source Recommendation ITU-T G.992.5
29、was approved on 13 January 2009 by ITU-T Study Group 15 (2009-2012) under Recommendation ITU-T A.8 procedures. Rec. ITU-T G.992.5 (01/2009) iii FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and commun
30、ication technologies (ICTs). The ITU Telecommunication Standardization Sector (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
31、 World Telecommunication Standardization Assembly (WTSA), which meets every 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
32、. In some areas of information technology which fall within ITU-Ts purview, 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 r
33、ecognized operating agency. Compliance with this Recommendation is voluntary. 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
34、 words “shall“ or some other obligatory language such as “must“ and the negative 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
35、that the practice or implementation of this Recommendation may involve the 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 Recommen
36、dation development process. As of the date of approval of this Recommendation, ITU had/had not 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 informatio
37、n and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2009 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. iv Rec. ITU-T G.992.5 (01/2009) CONTENTS Page 1 Sc
38、ope 1 2 References. 2 3 Definitions 3 4 Abbreviations and acronyms 3 5 Reference models 3 6 Transport protocol-specific transmission convergence (TPS-TC) function . 3 6.1 Transport capabilities . 3 7 Physical media-specific transmission convergence (PMS-TC) function . 3 7.1 Transport capabilities .
39、3 7.2 Additional functions . 3 7.3 Block interface signals and primitives . 3 7.4 Block diagram and internal reference point signals . 3 7.5 Control parameters . 4 7.6 Frame structure . 4 7.7 Data plane procedures 5 7.8 Control plane procedures 5 7.9 Management plane procedures . 5 7.10 Initializati
40、on procedures . 5 7.11 On-line reconfiguration 7 7.12 Power management mode . 7 8 Physical media-dependent function 7 8.1 Transport capabilities . 7 8.2 Additional functions . 7 8.3 Block interface signals and primitives . 7 8.4 Block diagram and internal reference point signals . 7 8.5 Control para
41、meters . 7 8.6 Constellation encoder for data symbols . 15 8.7 Constellation encoder for synchronization and L2 exit symbols . 15 8.8 Modulation . 15 8.9 Transmitter dynamic range . 17 8.10 Transmitter spectral masks . 17 8.11 Control plane procedures 17 8.12 Management plane procedures . 17 8.13 In
42、itialization procedures . 18 8.14 Short initialization procedures 30 8.15 Loop diagnostics mode procedures 30 8.16 On-line reconfiguration of the PMD function 38 Rec. ITU-T G.992.5 (01/2009) v Page 8.17 Power management in the PMD function 38 9 Management protocol-specific transmission convergence (
43、MPS-TC) functions . 38 9.1 Transport functions . 38 9.2 Additional functions . 38 9.3 Block interface signals and primitives . 38 9.4 Management plane procedures . 39 10 Dynamic behaviour . 41 Annex A Specific requirements for an ADSL system operating in the frequency band above POTS 42 A.1 ATU-C fu
44、nctional characteristics (pertains to clause 8) 42 A.2 ATU-R functional characteristics (pertains to clause 8) 47 A.3 Initialization 50 A.4 Electrical characteristics . 51 Annex B Specific requirements for an ADSL system operating in the frequency band above ISDN as defined in Appendices I and II of
45、 Recommendation ITU-T G.961 52 B.1 ATU-C functional characteristics (pertains to clause 8) 52 B.2 ATU-R functional characteristics (pertains to clause 8) 57 B.3 Initialization 60 B.4 Electrical characteristics . 60 Annex C Specific requirements for an ADSL system operating in the same cable as ISDN
46、as defined in Appendix III of Recommendation ITU-T G.961 62 Annex D ATU-C and ATU-R state diagrams . 63 Annex E POTS and ISDN basic access splitters . 63 Annex F ATU-x performance requirements for region A (North America) . 64 F.1 Performance requirements for operation of ADSL over POTS (Annex A) .
47、64 F.2 Performance requirements for operation of all-digital mode ADSL (Annex I) 64 Annex G ATU-x performance requirements for region B (Europe) . 65 G.1 Performance requirements for operation of ADSL over POTS (Annex A) . 65 G.2 Performance requirements for operation of ADSL over ISDN (Annex B) 65
48、G.3 Performance requirements for operation of all-digital mode ADSL (Annex I) 65 G.4 Performance requirements for operation of all-digital mode ADSL (Annex J) 65 Annex H Specific requirements for a synchronized symmetrical DSL (SSDSL) system operating in the same cable binder as ISDN as defined in A
49、ppendix III of Recommendation ITU-T G.961 66 Annex I All-digital mode ADSL with improved spectral compatibility with ADSL over POTS 67 I.1 ATU-C functional characteristics (pertains to clause 8) 67 vi Rec. ITU-T G.992.5 (01/2009) I.2 ATU-R functional characteristics (pertains to clause 8) 70 Page I.3 Initialization . 72 I.4 Electrical characteristics 72 Annex J All-digital mode ADSL with improved spectral compatibility with ADSL over ISDN . 74 J.1 ATU-C functional characteristics
