1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T G.992.4TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (07/2002) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital sections and digital line system Access networks Splitterless asymmetric digital subscriber line transceivers 2
2、 (splitterless ADSL2) ITU-T Recommendation G.992.4 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
3、 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.450G.49
4、9 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 fibre cable systems G.910G.919 Digital sections at hierarchic
5、al 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 systems for cus
6、tomer 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 G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DIGITAL TERMINAL EQUIPMENTS G.7000
7、G.7999 DIGITAL NETWORKS G.8000G.8999 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. G.992.4 (07/2002) i ITU-T Recommendation G.992.4 Splitterless asymmetric digital subscriber line transceivers 2 (splitterless ADSL2) Summary This Recommendation describes the inter
8、face between the telecommunications network and the customer installation in terms of their interaction and electrical characteristics. G.992.4 allows the transmission of POTS and V-series data services simultaneously with a digital channel over a single mixed gauge twisted metallic pair. Operation
9、in a TCM-ISDN noise environment is for further study. This Recommendation is structured as a delta document to ITU-T Rec. G.992.3. This Recommendation includes procedures to allow provisioning without the need for “splitters“, typically installed at the ingress to the customer premises. Additionally
10、, power management procedures and link states are specified to achieve power savings at the central office and customer premises. This Recommendation describes the second generation of splitterless ADSL, based on the first generation ITU-T Rec. G.992.2. This Recommendation may be easily implemented
11、in multi-mode devices that support both G.992.4 and G.992.2 with the following major additions and revisions: Improved application support for an all digital mode of operation and voice over ADSL operation. A new packet TPS-TC function and a STM TPS-TC function in addition to the existing ATM suppor
12、t. Support for IMA in the ATM TPS-TC. Improved configuration capability for each TPS-TC with configuration of latency, BER and minimum, maximum and reserve data rate. New line diagnostic procedures available for both successful and unsuccessful initialization scenarios. Enhanced on-line reconfigurat
13、ion capabilities including bit-swaps, dynamic rate repartitioning, and seamless rate adaptation. A more flexible TPS-TC function including support for up to 4 frame bearers, 4 latency paths, and control parameters allowing enhanced configuration of the overhead channel. Performance improvements incl
14、uding mandatory support for R = 16, one-bit constellations, and trellis coding. A more robust initialization procedure that includes splitterless capability features of the G.992.2 fast retrain procedure, CO and CP controlled adaptive signal durations, receiver determined adaptive frequency modulati
15、on for data exchange, and an optional adaptive length fast start-up procedure. Improved RFI and spectrum management tools including transmit power cutback at both ends of the line, spectrum shaping, sub-carrier black-out lists to avoid RFI, and improved sub-carrier ordering to help mitigate the prop
16、agation of RFI from sub-carrier to sub-carrier. Power saving features including mandatory reduction of excess margin under management layer control and a new L2 power management link state with low power features for the central office. Source ITU-T Recommendation G.992.4 was prepared by ITU-T Study
17、 Group 15 (2001-2004) and approved under the WTSA Resolution 1 procedure on 29 July 2002. ii ITU-T Rec. G.992.4 (07/2002) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Se
18、ctor (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 World Telecommunication Standardization Assembly (WTSA), which meets eve
19、ry 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. In some areas of information technology which fall within ITU-Ts purvie
20、w, 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 recognized operating agency. INTELLECTUAL PROPERTY RIGHTS ITU draws attent
21、ion to the possibility 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
22、outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the la
23、test information and are therefore strongly urged to consult the TSB patent database. ITU 2003 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. G.992.4 (07/2002) iii CONTENTS Page 1 Scope 1 2 Referenc
24、es. 2 3 Definitions 2 4 Abbreviations 2 5 Reference models 2 5.1 ATU functional model 2 5.2 User plane protocol reference model 3 5.3 Management plane reference model. 3 5.4 Application models. 4 5.4.1 Data service 4 5.4.2 Data with POTS service . 4 5.4.3 Intentionally left blank . 5 5.4.4 Voice ove
25、r data service 5 6 Transport Protocol Specific Transmission Convergence (TPS-TC) function 5 7 Physical Media Specific Transmission Convergence (PMS-TC) function 5 8 Physical Media Dependent (PMD) function. 5 9 Management Protocol Specific Transmission Convergence (MPS-TC) functions 6 10 Control Prot
26、ocol Specific Transmission Convergence (CPS-TC) functions 6 11 Dynamic behaviour. 6 Annex A Specific requirements for an ADSL system operating in the frequency band above POTS 7 A.1 ATU-C functional characteristics (pertains to clause 8) 7 A.1.1 ATU-C PMD control parameter settings 7 A.1.2 ATU-C dow
27、nstream transmit spectral mask for overlapped spectrum operation. 7 A.1.3 ATU-C transmitter PSD mask for non-overlapped spectrum operation 9 A.2 ATU-R functional characteristics (pertains to clause 8) 11 A.3 Intentionally left blank . 11 A.4 Electrical characteristics. 11 Annex B (void annex). 11 An
28、nex C Specific requirements for an ADSL system operating in the same cable as ISDN as defined in ITU-T Rec. G.961 Appendix III . 11 iv ITU-T Rec. G.992.4 (07/2002) Page Annex D ATU-C and ATU-R state diagrams. 12 Annex E POTS and ISDN-BA splitters 12 Annex F ATU performance requirements for Region A
29、(North America). 12 Annex G (void annex). 12 Annex H (void annex). 12 Annex I All digital mode ADSL with improved spectral compatibility with ADSL over POTS 13 I.1 ATU-C functional characteristics (pertains to clause 8) 13 I.1.1 ATU-C control parameter settings . 13 I.1.2 ATU-C downstream transmit s
30、pectral mask for overlapped spectrum operation. 13 I.1.3 ATU-C downstream transmit spectral mask for non-overlapped spectrum operation. 15 I.2 ATU-R functional characteristics (pertains to clause 8) 15 I.3 Intentionally left blank . 15 I.4 Electrical characteristics. 16 Annex J (void annex) 16 Annex
31、 K TPS-TC functional descriptions 16 ITU-T Rec. G.992.4 (07/2002) 1 ITU-T Recommendation G.992.4 Splitterless asymmetric digital subscriber line transceivers 2 (splitterless ADSL2) 1 Scope This Recommendation describes the interface between the telecommunications network and the customer installatio
32、n in terms of their interaction and electrical characteristics. The requirements of this Recommendation apply only to a single asymmetric digital subscriber line (ADSL). ADSL allows the provision of voiceband services, including POTS and V-series data services, and a number of digital channels. This
33、 Recommendation is structured as a delta document to ITU-T Rec. G.992.3. The transmission system is designed to operate on mixed gauge two-wire twisted metallic pairs over the existing copper facilities and over the customer premises wiring. The transmission system is based on the use of loop plant
34、cables without loading coils. Bridged taps in the loop plant are acceptable in all but a few unusual situations. Operation in a TCM-ISDN noise environment is for further study. An overview of Digital Subscriber Line Transceivers can be found in ITU-T Rec. G.995.1. This Recommendation describes the s
35、econd generation of splitterless ADSL, based on the first generation ITU-T Rec. G.992.2. This Recommendation is easily implemented in multi-mode devices that support both G.992.4 and G.992.2 with the following major additions or revisions: Improved application support for an all digital mode of oper
36、ation and voice over ADSL operation. A new packet TPS-TC function and a STM TPS-TC function in addition to the existing ATM support. Support for IMA in the ATM TPS-TC. Improved configuration capability for each TPS-TC with configuration of latency, BER and minimum, maximum and reserve data rate. New
37、 line diagnostic procedures available for both successful and unsuccessful initialization scenarios. Enhanced on-line reconfiguration capabilities including bit-swaps, dynamic rate repartitioning, and seamless rate adaptation. A more flexible TPS-TC function including support for up to 4 frame beare
38、rs, 4 latency paths, and control parameters allowing enhanced configuration of the overhead channel. Performance improvements including mandatory support for R = 16, one-bit constellations, and trellis coding. A more robust initialization procedure that includes splitterless capability features of t
39、he G.992.2 fast retrain procedure, CO and CP controlled adaptive signal durations, receiver determined adaptive frequency modulation for data exchange, and an optional adaptive length fast start-up procedure. Improved RFI and spectrum management tools including transmit power cutback at both ends of
40、 the line, spectrum shaping, sub-carrier black-out lists to avoid RFI, and improved sub-carrier ordering to help mitigate the propagation of RFI from sub-carrier to sub-carrier. Power saving features including mandatory reduction of excess margin under management layer control and a new L2 mode with
41、 low power features for the central office. 2 ITU-T Rec. G.992.4 (07/2002) 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated
42、were valid. All Recommendations are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly
43、 published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation 1 ITU-T Recommendation G.994.1 (2002), Handshake procedures for Digital Subscriber Line (DSL) transceivers. 2 ITU-T Recommendation G.992.3 (2002), Asymmetric
44、 Digital Subscriber Line transceivers 2 (ADSL2). 3 ITU-T Recommendation G.997.1 (1999), Physical layer management for Digital Subscriber Line (DSL) transceivers. 3 Definitions The definitions in clause 3/G.992.3 shall apply for this Recommendation. 4 Abbreviations The abbreviations in clause 4/G.992
45、.3 shall apply for this Recommendation. 5 Reference models G.992.4 devices fit within the XDSL Recommendations described in ITU-T Rec. G.995.1. Additionally, G.992.4 devices rely upon constituent components described within ITU-T Recs G.994.1 and G.997.1. This clause provides the necessary functiona
46、l, application, and protocol reference models so that the subclauses of G.992.4 may be related to these additional Recommendations. 5.1 ATU functional model The ATU functional model for G.992.4 shall be identical to that provided in 5.1/G.992.3. Figure 5-1/G.992.3 is duplicated here for reference. I
47、TU-T Rec. G.992.4 (07/2002) 3 G.992.4_F05-1PMDPMS-TCMPS-TCTPS-TC #0I/FTPS-TC #1I/FApplicationinterface(s)UPMDPMS-TCTPS-TC #0TPS-TC #1I/FI/FApplicationinterface(s)MPS-TCATU-RATU-CApplication specific Application invariant Application specificUnspecified Annexes Main body UnspecifiedAnnexesNTRNTROAMin
48、terfaceOAMinterfaceCCRRFigure 5-1/G.992.4 ATU functional model 5.2 User plane protocol reference model The user plane protocol reference model of G.992.4 shall be as defined in 5.2/G.992.3. Figure 5-2/G.992.3 is duplicated here for reference. G.992.4_F05-2UPMDPMS-TCPMDTPS-TCPhysical TP mediaS/TUser
49、data interfaceInternal interfaceATU-RATU-C NT1, NT1/2LTTransport protocols (e.g., ATM)PMS-TCTPS-TCTransport protocols (e.g., ATM)NotspecifiedNotspecifiedLT internalinterfaceCRCRFigure 5-2/G.992.4 User plane protocol reference model 5.3 Management plane reference model The management plane protocol reference model of G.992.4 shall be as defined for G.992.3 in 5.3/G.992.3. Figure 5-3/G.992.3 is duplicated here for reference. 4 ITU-T Rec. G.992.4 (07/2002) G.992.4_F05-3UPMDPMS-TCPM
