1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T G.992.1TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 1(03/2003) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital sections and digital line system Access networks Asymmetric digital subscriber line (ADSL) transceiv
2、ers Amendment 1: Revised Annex C, new Annex I and new Appendix V ITU-T Recommendation G.992.1 (1999) Amendment 1 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 A
3、LL ANALOGUE 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.4
4、49 COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY G.450G.499 TESTING EQUIPMENTS G.500G.599 TRANSMISSION MEDIA 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
5、 fibre cable systems G.910G.919 Digital sections at 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.950
6、G.959 Digital section and digital transmission systems 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 Access networks G.990G.999 QUALITY OF SERVICE AND PERFORMANCE - GENERIC AND USER-RELATED ASPECT
7、S G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DIGITAL TERMINAL EQUIPMENTS G.7000G.7999 DIGITAL NETWORKS G.8000G.8999 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. G.992.1 (1999)/Amd.1 (03/2003) i ITU-T Recommendation G.992.1 Asymmetric digital su
8、bscriber line (ADSL) transceivers Amendment 1 Revised Annex C, new Annex I and new Appendix V Summary This amendment provides the G.992.1 revision (revision of Annex C, addition of Annex I and addition of Appendix V). It includes the changes introduced by G.992.1 (1999) Corrigendum 2. Revised Annex
9、C covers specific requirements for an ADSL system operating in the same cable as ISDN as defined in Appendix III/G.961. Annex I covers ADSL system with improved performance on short loops operating in the same cable as TCM-ISDN as defined in Appendix III/G.961. Appendix V contains some example overl
10、apped PSD Masks for use in a TCM-ISDN crosstalk environment. Source Amendment 1 to ITU-T Recommendation G.992.1 (1999) was approved by ITU-T Study Group 15 (2001-2004) under the ITU-T Recommendation A.8 procedure on 16 March 2003. This amendment includes ITU-T Rec. G.992.1 (1999) Amendment 1/Corrige
11、ndum 1 (12/2003). ii ITU-T Rec. G.992.1 (1999)/Amd.1 (03/2003) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsi
12、ble 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 topics for study by the ITU-
13、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 prepared on a collaborative
14、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 Recommendation may contain certain mandat
15、ory 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 to express requirements. The u
16、se 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 claimed Intellectual Property Right. ITU takes n
17、o 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 of intellectual property, pro
18、tected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. ITU 2004 All rights reserved. No part of this publication may be repr
19、oduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. G.992.1 (1999)/Amd.1 (03/2003) iii CONTENTS Page Amendment 1 Revised Annex C, new Annex I and new Appendix V. 1 Annex C Specific requirements for an ADSL system operating in the same cable as ISDN as defined in
20、Appendix III of ITU-T Rec. G.961. 1 C.1 Scope 1 C.2 Terms and abbreviations. 1 C.3 Reference models . 2 C.4 ATU-C functional characteristics (pertains to clause 7) 8 C.5 ATU-R functional characteristics (pertains to clause 8) 17 C.6 EOC Operation and Maintenance (pertains to clause 9) 23 C.7 Initial
21、ization (pertains to clause 10) . 24 C.8 AOC On-line adaptation and reconfiguration (pertains to clause 11) 45 Annex I Specific requirements for an ADSL system with improved performance on short loops operating in the same cable as ISDN as defined in Appendix III of ITU-T Rec. G.961. 47 I.1 Scope 47
22、 I.2 Terms and abbreviations. 47 I.3 Reference models . 48 I.4 ATU-C functional characteristics (pertains to clause 7) 53 I.5 ATU-R functional characteristics (pertains to clause 8) 70 I.6 EOC operation and maintenance (pertains to clause 9) 76 I.7 Initialization (pertains to clause 10) . 77 I.8 AOC
23、 On-line adaptation and reconfiguration (pertains to clause 11) 98 I.9 POTS splitter 100 Appendix V Example overlapped PSD masks for use in a TCM-ISDN crosstalk environment 100 V.1 Example downstream PSD masks for use with Profiles 5 and 6 100 V.2 Example downstream PSD mask for use with Profile 3.
24、102 ITU-T Rec. G.992.1 (1999)/Amd.1 (03/2003) 1 ITU-T Recommendation G.992.1 Asymmetric digital subscriber line (ADSL) transceivers Amendment 1 Revised Annex C, new Annex I and new Appendix V Annex C Specific requirements for an ADSL system operating in the same cable as ISDN as defined in Appendix
25、III of ITU-T Rec. G.961 C.1 Scope This annex describes those specifications that are unique to an ADSL system coexisting in the same binder as TCM-ISDN as defined in Appendix III/G.961. The clauses in this annex provide supplementary and replacement material to the clauses in the main body. The natu
26、re of the material is parenthetically indicated in the clause heading. The modifications described in this annex allow a performance improvement from the ADSL system specified in Annex A in an environment coexisting with TCM-ISDN in the same cable. This annex also defines those parameters of this AD
27、SL system that have been left undefined in the main body of this Recommendation. It is recommended that ADSL system implementing Annex C also implements Annex A. This annex defines several optional operating modes or “profiles“, negotiable through G.994.1, to allow limited independent control of: FE
28、XT and NEXT period transmission in both upstream and downstream directions; overlapped and non-overlapped spectrum downstream during FEXT and NEXT periods. These new optional profiles (defined in C.3.4 as Profiles 1 to 6) offer improved robustness and extended reach compared to the previously define
29、d operating modes. C.2 Terms and abbreviations C.2.1 Definitions This annex defines the following terms: C.2.1.1 bitmap-FC: ATU-R transmitter bitmap under TCM-ISDN FEXT noise generated at ATU-C. C.2.1.2 bitmap-FR: ATU-C transmitter bitmap under TCM-ISDN FEXT noise generated at ATU-R. C.2.1.3 bitmap-
30、NC: ATU-R transmitter bitmap under TCM-ISDN NEXT noise generated at ATU-C. C.2.1.4 bitmap-NR: ATU-C transmitter bitmap under TCM-ISDN NEXT noise generated at ATU-R. C.2.1.5 dual bitmap: The Dual Bitmap method has dual bit rates under the FEXT and NEXT noise from TCM-ISDN. 2 ITU-T Rec. G.992.1 (1999)
31、/Amd.1 (03/2003) C.2.1.6 FEXT bitmap: Similar to the Dual Bitmap method, however, transmission only occurs during FEXT noise from TCM-ISDN. C.2.1.7 FEXTCduration: TCM-ISDN FEXT duration at ATU-C estimated by the ATU-R. C.2.1.8 FEXTCsymbol: DMT symbol transmitted by ATU-R during TCM-ISDN FEXT. C.2.1.
32、9 FEXTRduration: TCM-ISDN FEXT duration at ATU-R estimated by the ATU-C. C.2.1.10 FEXTRsymbol: DMT symbol transmitted by ATU-C during TCM-ISDN FEXT. C.2.1.11 hyperframe: 5-superframe structure which synchronized TTR. C.2.1.12 NEXTCduration: TCM-ISDN NEXT duration at ATU-C estimated by the ATU-R. C.2
33、.1.13 NEXTCsymbol: DMT symbol transmitted by ATU-R during TCM-ISDN NEXT. C.2.1.14 NEXTRduration: TCM-ISDN NEXT duration at ATU-R estimated by the ATU-C. C.2.1.15 NEXTRsymbol: DMT symbol transmitted by ATU-C during TCM-ISDN NEXT. C.2.1.16 subframe: Ten consecutive DMT symbols (except for sync symbols
34、) according to TTR timing. C.2.2 Abbreviations This annex uses the following abbreviations: NSWFSliding Window frame counter TTR TCM-ISDN Timing Reference TTRCTiming reference used in ATU-C TTRRTiming reference used in ATU-R UI Unit Interval C.3 Reference models C.3.1 ATU-C transmitter reference mod
35、el (replaces figures in 5.1) See Figures C.1 and C.2. ITU-T Rec. G.992.1 (1999)/Amd.1 (03/2003) 3 G.992.1AMD.1_FC.1AS0AS1AS2AS3LS0LS1LS2NTROAMV-CibMux/synccontrolcrcfcrciReference pointsAMuxdata frameBFEC outputdata frameCConstellationencoder inputdata frameInter-leaverToneorderingConstel-lationenco
36、derandgainscalingIDFT480 Outputparallel/serialbufferZii = 1 to 255DAC and analogueprocessingScram-bler16 or m0 32 kbit/s)LS1 (m1 32 kbit/s)LS2 (m2 32 kbit/s)NTROperations, maintenance and controlATU-CTwisted pairV-CTTRNOTE 1 Optional bearer channels (both duplex and simplex) and features are shown w
37、ith dotted lines.NOTE 2 TTR may be generated in the ATU-C without being provided from the V-C reference point.Figure C.8/G.992.1 ATU-C functional interfaces for STM transport at the V-C reference point C.4.1.2 Payload transfer delay (supplements 7.1.4) Since Annex C uses a rate converter, the maximu
38、m payload transfer delay is longer than specified values in 7.1.4. The additional one-way transfer delay due to the rate converters shall be less than 1.7 ms for fast data and 13 ms for interleaved data. C.4.2 ATM transmission protocols specific functionalities (pertains to 7.2) C.4.2.1 ATU-C input
39、and output V interface for ATM transport (replaces figure in 7.2.1) See Figure C.9. ITU-T Rec. G.992.1 (1999)/Amd.1 (03/2003) 9 G.992.1AMD.1_FC.9ATM layerPORT0PORT1ATM0ATM1Tx_ATM0Tx_Cell_Handshake0Rx_ATM0Rx_Cell_Handshake0Tx_ATM1Tx_Cell_Handshake1Rx_ATM1Rx_Cell_Handshake1NTRTTROperations, administra
40、tion,maintenance and controland interface todigital networkATU-CTwisted pairV-CNOTE TTR can be generated in the ATU-C without being provided from the V-C reference point.Figure C.9/G.992.1 ATU-C functional interfaces to the ATM layer at the V-C reference point C.4.2.2 Payload transfer delay (supplem
41、ents 7.2.2) Since Annex C uses a rate converter, the maximum payload transfer delay is longer than specified values in 7.2.2. The additional one-way transfer delay due to the rate converters shall be less than 1.7 ms for fast data and 13 ms for interleaved data. C.4.3 Framing (pertains to 7.4) C.4.3
42、.1 Superframe structure (supplements 7.4.1.1) Since the rate converter reorders the user data and overhead bit-level data to create hyperframes, the input data frames to the constellation encoder are different than those defined in 7.4.1.1. C.4.3.2 Hyperframe structure (replaces 7.4.1.3) Annex C use
43、s the hyperframe structure shown in Figure C.10. Figure C.10 shows the phase relationship between the TTRCand the hyperframe at the point U-C. Each hyperframe is composed of 5 superframes, which are numbered from 0 to 4. In order to indicate the boundary of the hyperframe, the inverse synch symbol i
44、s used for the 4th superframe (SPF#3), which is generated from a tone-by-tone 180-degree phase reversal of the synchronization symbol (see C.4.7.1) except for the pilot tone. 10 ITU-T Rec. G.992.1 (1999)/Amd.1 (03/2003) G.992.1AMD.1_FI.10(Point B) 5 superframes (= 340 frames)1 Superframe = 68 frames
45、 (17 ms)Rate converter(Point U-C, including synch symbol)TTR Clock(TC)#0 = 2.5 msFEXTNEXTATU-RcrosstalkATU-C transmitDMT symbolFFFF FFNNNNNN F FFSSS INNSliding window1 frame = 250 sTC#27 TC#33NEXTFEXTHyperframe = 345 symbols (85 ms)SPF#1 SPF#2 SPF#3 SPF#4Superframe (SPF#0) = 69 symbols (17 ms)1 symb
46、ol = 264 s (544 samples)ISFNSInverse synch symbolNEXTRSynch symbolSymbol using Bitmap-FR(FEXTRduration bitmap)Symbol using Bitmap-NR(NEXTRduration bitmap)FEXTR Synch symbolFEXTRdurationTTRFigure C.10/G.992.1 Hyperframe structure for downstream The bit-level data stream from the rate-converter is ext
47、racted according to the size of Bitmap-FRand Bitmap-NRusing the sliding window (see C.3.3.2). In order to make the bit rate to be a multiple of 32 kbit/s, the dummy bits are inserted at the end of hyperframe by the rate converter (see C.4.4.2). The hyperframe is composed of 345 DMT symbols, numbered
48、 from 0 to 344. Each symbol is assigned as FEXTRor NEXTRsymbol in a FEXTRor NEXTRduration (see C.2), and the following numerical formula gives the information which duration Ndmt-th DMT symbol belongs to at ATU-C transmitter (see Figure C.11). ITU-T Rec. G.992.1 (1999)/Amd.1 (03/2003) 11 G.992.1AMD.
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