1、 International Telecommunication Union ITU-T G.992.3TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 4(10/2011) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital sections and digital line system Access networks Asymmetric digital subscriber line transceivers 2 (
2、ADSL2) Amendment 4 Recommendation ITU-T G.992.3 (2009) Amendment 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.200
3、G.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 LINE TEL
4、EPHONY 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 hier
5、archical 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 f
6、or 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.999MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTIC
7、S 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.992.3 (2009)/Amd.4 (10/2011) i Recommendation ITU-T G.992.3 Asymmetric digital
8、subscriber line transceivers 2 (ADSL2) Amendment 4 Summary Functionalities covered in Amendment 4 to Recommendation ITU-T G.992.3 (2009) (also apply to Recommendation ITU-T G.992.5 by reference): Correction to CIpolicy=1 (corrigendum). Extended valid values for Lpin L2 low power mode (amendment). Ex
9、tended valid values for the gigain scaling in L2 low power mode (amendment). History Edition Recommendation Approval Study Group 1.0 ITU-T G.992.3 2002-07-29 15 1.1 ITU-T G.992.3 (2002) Amd. 1 2003-05-22 15 1.2 ITU-T G.992.3 (2002) Cor. 1 2003-12-14 15 1.3 ITU-T G.992.3 (2002) Cor. 2 2004-02-22 15 1
10、.4 ITU-T G.992.3 (2002) Amd. 2 2004-04-30 15 1.5 ITU-T G.992.3 (2002) Amd. 3 2004-06-13 15 1.6 ITU-T G.992.3 (2002) Amd. 4 2004-06-13 15 2.0 ITU-T G.992.3 2005-01-13 15 2.1 ITU-T G.992.3 (2005) Amd. 1 2005-09-22 15 2.2 ITU-T G.992.3 (2005) Amd. 2 2006-03-29 15 2.3 ITU-T G.992.3 (2005) Amd. 3 2006-12
11、-14 15 2.4 ITU-T G.992.3 (2005) Amd. 4 2007-07-29 15 2.5 ITU-T G.992.3 (2005) Amd. 5 2008-06-22 15 3.0 ITU-T G.992.3 2009-04-22 15 3.1 ITU-T G.992.3 (2009) Cor. 1 2009-11-13 15 3.2 ITU-T G.992.3 (2009) Amd. 1 2010-03-01 15 3.3 ITU-T G.992.3 (2009) Amd. 2 2010-07-29 15 3.4 ITU-T G.992.3 (2009) Amd. 3
12、 2010-11-29 15 3.5 ITU-T G.992.3 (2009) Cor. 2 2011-06-22 15 3.6 ITU-T G.992.3 (2009) Amd. 4 2011-10-29 15 ii Rec. ITU-T G.992.3 (2009)/Amd.4 (10/2011) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information an
13、d communication 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 ba
14、sis. The 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 Reso
15、lution 1. 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
16、 and a recognized 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 ar
17、e met. The 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 po
18、ssibility 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 th
19、e 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, implementers are cautioned that this may not represent the latest informat
20、ion and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2012 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 (2009)/Amd.4 (10/2011) iii Ta
21、ble of Contents Page 1) Clause 7.10.3 (corrigendum) 1 2) Extended valid values for Lpin L2 low power mode (amendment) . 1 3) Extended valid values for the gigain scaling in L2 low power mode (amendment) 3 Rec. ITU-T G.992.3 (2009)/Amd.4 (10/2011) 1 Recommendation ITU-T G.992.3 Asymmetric digital sub
22、scriber line transceivers 2 (ADSL2) Amendment 4 1) Clause 7.10.3 (corrigendum) Make the following correction to the channel initialization policy: 7.10.3 Exchange phase Policy ONE: if CIpolicyn= 1, then: a) If the minimum net data rate (see clause 7.3.2.1.1 of ITU-T G.997.1) is set equal to the maxi
23、mum net data rate (see clause 7.3.2.1.3 of ITU-T G.997.1), then: 1) Maximize INP_actnfor the bearer channel #n. b) If the minimum net data rate (see clause 7.3.2.1.1 of ITU-T G.997.1) is not set equal to the maximum net data rate (see clause 7.3.2.1.3 of ITU-T G.997.1), then: 1) Maximize net data ra
24、te for all the bearer channels, per the allocation of the net data rate, in excess of the sum of the minimum net data rates over all bearer channels (see clause 7.10.2). 2) If such maximized net data rate is equal to the maximum net data rate (see clause 7.3.2.1.3 of ITU-T G.997.1), maximize INP_act
25、nfor the bearer channel #n. 3) Minimize excess margin with respect to the maximum noise margin MAXSNRM through gain scalings (see clause 8.6.4). Other control parameters may be used to achieve this (e.g., PCB, see clause 8.13.3). If the CO-MIB sets CIPOLICY (see clause 7.3.2.10 of ITU-T G.997.1) to
26、ONE for a bearer channel, and it shall have the minimum net data rate (see clause 7.3.2.1.1 of ITU-T G.997.1) is set equal to the maximum net data rate (see clause 7.3.2.1.3 of ITU-T G.997.1), itand shall have the MAXSNRM set to infinity (see clause 7.3.1.3.3 of ITU-T G.997.1). 2) Extended valid val
27、ues for Lpin L2 low power mode (amendment) Change clause 7.12.1.1 as follows: 7.12.1.1 Transition to L2 link state operation The L0 to L2 transition procedures of the PMS-TC function supports changing some of the control parameters to reduce the number of bits transferred per PMD primitive in the do
28、wnstream direction. This change is accomplished by changing the downstream control parameter displayed in Table 7-8. The transition is intended to allow changes in the downstream control parameters without errors (i.e., seamless). 2 Rec. ITU-T G.992.3 (2009)/Amd.4 (10/2011) Table 7-23 Power manageme
29、nt control parameters of the PMS-TC function Parameter Definition LpThe number of bits from latency path #p shall be decreased from Lpin the L0 link state in the range of 1 Lp 1024 and Lpshall be such that 8 Lp 1024. Entry into the L2 link state occurs with the coordinated change in the downstream L
30、pparameters in order to decrease the number of bits per PMD primitive. The change shall be preceded by the protocol described in clause 9.5.3.3. Following the successful completion of the protocol, the coordinated change of the Lpparameters shall occur as specified in clause 7.11.1.2. The ATUs shall
31、 store the L0 link state PMS-TC control parameter Lpwhen transitioning from link state L0 to state L2. Add NOTE to clause 9.4.1.7.3 as follows: 9.4.1.7.3 L2 request by ATU-C When sending the L2 request command, the ATU-C shall specify parameters describing the minimum and maximum average power cutba
32、ck, defined in terms of the PMD control parameter PCBds. The ATU-C shall also specify the minimum and maximum Lpvalue for each configured PMS-TC latency path function. Values larger than the current Lpvalues shall not be encoded. Upon receipt of the L2 request command, the ATU-R shall evaluate the p
33、arameters found in the L2 request message and the current operating conditions of the downstream receiver. If the parameters are invalid (i.e., not within the allowed encoding ranges), the ATU-R shall send an L2 reject command using reason code 0216. NOTE An ATU-R implemented according to previous v
34、ersions of this Recommendation may have a valid range for Lplimited to 1024. Therefore, it may send a L2 Reject command using reason code 0216, in response to an L2 Request command with a minimum Lpvalue exceeding 1024. If the parameters are valid but describe an operating condition that cannot be c
35、urrently satisfied (e.g., because the current line and noise conditions cannot support the configuration), the ATU-R shall send an L2 reject command using reason code 0416. If the parameters can be met, the ATU-R shall send an L2 grant command and follow procedures defined in clause 9.5.3.3. The L2
36、grant command shall contain the actual value of PCBds necessary modifications to the bits and gain tables to be used by the ATUs in the downstream direction. Additionally, the grant command shall describe the PCBds and the bi/giflag value that the ATU-C shall use to transmit an L2 exit sequence as d
37、escribed in clause 8.7. These should be selected by the receiver to best assure reliable detection of the L2 exit sequence. A bi/giflag value of zero corresponds to the L0 link state; the value of 1 corresponds to the L2 link state. The ATU-R may instead send an L2 reject command indicating it is te
38、mporarily busy using reason code 0116. The ATU-R shall send a response command to an L2 request by the ATU-C within the time period defined in Table 7-17. An ATU-R shall not send an L2 grant command if it has already sent an OLR request command and is awaiting a response. Rec. ITU-T G.992.3 (2009)/A
39、md.4 (10/2011) 3 3) Extended valid values for the gigain scaling in L2 low power mode (amendment) Change clause 8.6.4 as follows: 8.6.4 Gain scaling These requirements on the bits and gains table apply in the L0 state. and aAt entry into the L2 state, the requirements for the bits table are unchange
40、d, but the following requirements on the gains table apply: If (bi 0) or (bi= 0), then gishall be in the 14.5 to +2.5 + EXTGI (dB) range; If (bi 0) or (bi= 0), then PCB(L2)+gi(L2) PCB(L0)+ RMSGI(L0)+2.5; The overall gains and PCB in L2 shall be such that ATP(L2) ATP(L0); If (gi(L0) 0) then (gi(L2) 0
41、). The L2 entry grant response message indicates the gains table to be used in the L2 state (see clause 9.4.1.7). NOTE 1 An ATU-R implemented according to previous versions of this Recommendation may send L2 entry grant response messages having a gains table according to L0 state constraints. Howeve
42、r, at entry into the L2 state, the excess margin may not be minimized. Power trimming during the L2 state may be used to minimize the excess margin. The L2 entry and trim grant response messages indicate the PCB value to be used in the L2 state (see clause 9.4.1.7). Power trimming is defined as chan
43、ging the downstream power cutback (PCBds) level, resulting in a change of the downstream reference transmit PSD (REFPSDds) level. Power trimming changes the PCBds value used during the L2 state and does not change the givalues determined at the time of entry into the L2 state. The givalues in dB sha
44、ll be defined as the 20 log gi(giin linear scale). A givalue of 14.5 dB corresponds to a giof 0.1888 in linear scale. A givalue of +2.5 dB corresponds to a givalue of 1.333 in linear scale. Same relationship shall be used for the tssivalues in dB and in linear scale. NOTE 2 The givalues define a sca
45、ling of the root mean square (rms) subcarrier power levels relative to the REFPSD level (see clause 8.13.5). They are independent of any methods that manufacturers may use to simplify implementation (e.g., constellation nesting). Printed in Switzerland Geneva, 2012 SERIES OF ITU-T RECOMMENDATIONS Se
46、ries A Organization of the work of ITU-T Series D General tariff principles Series E Overall network operation, telephone service, service operation and human factors Series F Non-telephone telecommunication services Series G Transmission systems and media, digital systems and networks Series H Audi
47、ovisual and multimedia systems Series I Integrated services digital network Series J Cable networks and transmission of television, sound programme and other multimedia signals Series K Protection against interference Series L Construction, installation and protection of cables and other elements of
48、 outside plant Series M Telecommunication management, including TMN and network maintenance Series N Maintenance: international sound programme and television transmission circuits Series O Specifications of measuring equipment Series P Terminals and subjective and objective assessment methods Serie
49、s Q Switching and signalling Series R Telegraph transmission Series S Telegraph services terminal equipment Series T Terminals for telematic services Series U Telegraph switching Series V Data communication over the telephone network Series X Data networks, open system communications and security Series Y Global information infrastructure, Internet protocol aspects and next-generation networks Series Z Languages and general software aspects for telecommunication systems
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