1、 International Telecommunication Union ITU-T G.9902TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 2(08/2013) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Access networks In premises networks Narrowband orthogonal frequency division multiplexing power line communi
2、cation transceivers for ITU-T G.hnem networks Amendment 2: Clarifications on payload encoder and addition of a network admission procedure Recommendation ITU-T G.9902 (2012) Amendment 2ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE
3、 CONNECTIONS AND CIRCUITS G.100G.199 GENERAL CHARACTERISTICS COMMON TO ALL 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-R
4、ELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES G.400G.449 COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY 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 LI
5、NE SYSTEM G.900G.999 MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DATA OVER TRANSPORT GENERIC ASPECTS G.7000G.7999 PACKET OVER TRANSPORT ASPECTS G.8000G.8999 ACCESS NETWORKS G.9000G.9999 In premises networ
6、ks G.9900G.9999For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T G.9902 (2012)/Amd.2 (08/2013) i Recommendation ITU-T G.9902 Narrowband orthogonal frequency division multiplexing power line communication transceivers for ITU-T G.hnem networks Amendment 2 Clarificatio
7、ns on payload encoder and addition of a network admission procedure Summary Amendment 2 to Recommendation ITU-T G.9902 (2012) contains: Corrections and clarifications on the payload encoder; The addition of a network admission procedure based on Recommendation ITU-T G.9961. History Edition Recommend
8、ation Approval Study Group 1.0 ITU-T G.9902 2012-10-29 15 1.1 ITU-T G.9902 (2012) Amd. 1 2013-03-16 15 1.2 ITU-T G.9902 (2012) Amd. 2 2013-08-29 15 ii Rec. ITU-T G.9902 (2012)/Amd.2 (08/2013) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the fie
9、ld of telecommunications, information and 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 standardiz
10、ing telecommunications on a worldwide basis. 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
11、 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 basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate
12、 both a telecommunication administration 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 w
13、hen 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 use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPE
14、RTY 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 no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserte
15、d 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, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that th
16、is may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2013 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU
17、-T G.9902 (2012)/Amd.2 (08/2013) 1 Recommendation ITU-T G.9902 Narrowband orthogonal frequency division multiplexing power line communication transceivers for ITU-T G.hnem networks Amendment 2 Clarifications on payload encoder and addition of a network admission procedure Modifications introduced by
18、 this amendment are shown in revision marks. Unchanged text is replaced by ellipsis (). Some parts of unchanged text (clause numbers, etc.) may be kept to indicate the correct insertion points. 2 References ITU-T G.9961 Recommendation ITU-T G.9961 (2010), Unified high-speed wire-line based home netw
19、orking transceivers Data link layer specification. 8.3.3 Payload encoder The functional diagram of the payload encoder is presented in Figure 8-9. It contains an FEC encoder, an aggregation and fragmentation block (AF), a fragment repetition encoder (FRE) and an interleaver. The FRE is to support a
20、robust communication mode (RCM) and is bypassed in the case of a normal mode of operation (no repetitions). Figure 8-9 Functional diagram of the payload encoder The incoming PHY frame payload bits shall be divided into m sequential information blocks of Klbytes per block, l = 1, 2, .m, and each info
21、rmation block shall be encoded by the FEC encoder, as described in clause 8.3.2. The valid values of FEC parameters K, R, and rI, and the coded block size NFECare presented in clause 8.3.2.3. The bytes in each information block shall be in the same order as they are in the corresponding MPDU. 2 Rec.
22、 ITU-T G.9902 (2012)/Amd.2 (08/2013) The AF first collects the FEC codeword block of NFECBbits generated by the FEC for the encoded payload. Furthermore, the FEC codeword block is partitioned into fragments of the same size B0bits each (e.g., B1 B4in Figure 8-10). The number of fragments is Nfrg= ce
23、iling(NFECB/B0). To obtain an integer number of fragments, the FEC codeword block shall be padded with up to BP= B0 Nfrg NFECBbits. Figure 8-10 Generation of the encoded payload block (case Nfrg= 4, cyclic shifting, interleaving and padding of fragments when in IoAC mode is not shown) The value of B
24、0shall be calculated as an integer divisor of the total number of bits in the FEC codeword block and then increased to fit an integer number of symbols. This shall be the maximum divisor for which the value is less than or equal to the minimum of: the total number of input bits, NFECB, in the FEC co
25、deword block; the total number of bits, NZC, loaded on the symbols that span at least 10 ms for the case of 50 Hz AC lines, and at least 8.33 ms for the case of 60 Hz AC lines or lines with no AC; the maximum fragment size of Bmax= 3072 bits. The number of bits used to fit B0to an integer number of
26、symbols shall not exceed the number of bits loaded onto a symbol (kp) minus 1. With the definitions above, the fragment size, B0, and the number of pad bits, BP, can be computed using the following steps: find the upper limit of the fragment size: P= min(NFECB, NZC, Bmax) find the preliminary number
27、 of fragments: Nfrg = ceiling(NFECB/P) find the fragment size: B0 = ceiling(NFECB/Nfrg); B0= kp ceiling (B0/ kp) find the final number of fragments: Nfrg= ceiling(NFECB/B0) find the number of pad bits BP= B0 Nfrg NFECB, Rec. ITU-T G.9902 (2012)/Amd.2 (08/2013) 3 where kpis the number of bits loaded
28、onto a symbol. The pad bits, BP, shall be generated by continuously extracting the MSB from the LFSR as shown in Figure 8-17 until the pad has filled up. The generation polynomial shall be as defined in clause 8.4.2.6. The LFSR initialization shall be all-ones as shown in Figure 8-17 prior to the fi
29、rst pad bit being extracted. The number of pad bits shall be less than Nfrg kp. Note that the actual B0size can be larger than P (by no more than kp bits). The FRE provides repetitions of fragments with the repetition rate of R. Each fragment shall be copied R times and all copies shall be concatena
30、ted into the fragment buffer, FB, so that the first bit of each copy follows the last bit of previous copy, see Figure 8-10. The total size of the FB is B0R bits. The FRE shall support the values R = 1, 2, 4, 6, 12 (value of R = 1 corresponds to the normal mode of operation). If R = 1, an FB, accord
31、ingly, shall contain a single fragment of B0bits. All fragments and their copies of each FB shall be interleaved. The interleaving method and parameters of the interleavers are defined in clause 8.3.5 and are the same for all valid values of R. Two modes of interleaving are defined: interleave-over-
32、fragment (IoF) interleave-over-AC-cycle (IoAC). The mode of interleaving is indicated in the PFH, as defined in clause 8.2.3.2.7 and shall be selected at the discretion of the transmitter. In both modes, for each fragment, prior to interleaving, the bits of each fragment copy starting from the secon
33、d copy (“Rep 2“ in Figure 8-10) shall be cyclically shifted by M = ceiling (B0/RT) bits relative to the previous copy in the direction from LSB to MSB, i.e., the copy “Rep(d+1)“ shall be shifted by d M bits relative to copy “Rep 1“ so that the LSB of copy “Rep 1“ will have bit number (d M) in the co
34、py “Rep(d+1)“. The value of RT R is the total number of repetitions, including padding; it depends on the mode of interleaving. If the IoF mode is set, each fragment of the FB shall be interleaved separately. After the interleaving of all copies of the fragment, the FB shall be passed for concatenat
35、ion. The value of RTshall be set equal to R. If the IoAC mode is set, each FB (containing R copies of the fragment) shall be padded to the closest integer number of symbols that is equal or more than the closest integer number of NZC, Figure 8-11. The pad shall be generated by cyclical repeating of
36、the bits of this same FB, starting from its first bit: the first bit of the pad shall follow the last bit of the FB and shall be the repetition of the first bit of the same FB. Furthermore, all copies of the fragment, both original and padded, shall be interleaved as defined in clause 8.3.5 for the
37、payload interleaver. The total number of interleaved copies is RT = ceiling(ceiling(B0 R)/NZC) NZC/B0). From the last copy, only the symbols that fill up the padded FB, as shown in Figure 8-11, shall be taken from the interleaver. After interleaving of all copies of the fragment, the padded FB shall
38、 be passed for concatenation. 4 Rec. ITU-T G.9902 (2012)/Amd.2 (08/2013) Figure 8-11 Padding of the FB in IoAC mode The FBs processed as described above shall be concatenated into an encoded payload block, in the order of the sourcing fragments, as shown in Figure 8-10. The encoded payload block is
39、passed for mapping into symbol frames (see clause 8.3.6). 9 Data link layer (DLL) specification In the present clause, the status of each requirement from the reference documents is given using the following convention: I = “Informative“. The statements of the reference document are provided for inf
40、ormation only. N = “Normative“: The statements of the reference document shall apply without modifications or remarks. S = “Selection“: The statements of the reference document shall apply with the selections specified. E = “Extension“: The statements of the reference document shall apply with the e
41、xtensions (modifications and remarks noted under the part title) specified. N/R = “Not Relevant“: The statements of the reference document do not apply. An explanation may be given under the part title. Rec. ITU-T G.9902 (2012)/Amd.2 (08/2013) 5 9.5 Domain management protocols 9.5.1 Network admissio
42、nSetup of a domain The Authentication and key management procedures are specified in ITU-T G.9961 using the selections and modifications listed in Table 9-34a. Table 9-34a Network admission selections from ITU-T G.9961 Clause number in ITU-T G.9961 Title and remarks/modifications Statement 8.6.1 Net
43、work admission MAP and MAP-D messages are not implemented in the current specification The node shall wait for the beacon message when the domain operates in synchronous or asynchronous beacon mode, as described in clause 9.3.4. The node may start the admission protocol without waiting for beacon me
44、ssage when the domain is operating in beaconless mode DEVICE_ID is replaced by NODE_ID and described in clause 9.3.1.2.2 of the current specification S 8.6.1.1 Network admission protocol N 8.6.1.1.1 Registration to the domain MAP message are replaced by Beacon or skipped in beaconless mode 1 second
45、timeout is replaced with REG_RESP_TIME ADM_NodeRegistRequest.req shall be sent with MA priority 2 DEVICE_ID is replaced by NODE_ID and described in clause 9.3.1.2.2 of the current specification S 8.6.1.1.2 Periodic re-registrations MAP message are replaced by Beacon or skipped in beaconless mode ADM
46、_DmRegistrRf message shall be sent with MA priority 2 S 8.6.1.1.3 Resignation from the domain N 8.6.1.1.3.1 Self-resignation 450 ms is replaced with RES_REQ_TIME DEVICE_ID is replaced by NODE_ID and described in clause 9.3.1.2.2 of the current specification S 8.6.1.1.3.2 Forced resignation 200 ms is
47、 replaced with FORCED_RES_REQ_TIME S 8.6.1.1.4 Registration and resignation messages N 8.6.1.1.4.1 Registration request message N 6 Rec. ITU-T G.9902 (2012)/Amd.2 (08/2013) Table 9-34a Network admission selections from ITU-T G.9961 Clause number in ITU-T G.9961 Title and remarks/modifications Statem
48、ent 8.6.1.1.4.2 Registration response message DEVICE_ID is replaced by NODE_ID and described in clause 9.3.1.2.2 of the current specification. The field size id expanded to 16 bits Bandplan field is not implemented Security field is extended to 64 bits (16 bits for NODE_ID and 48 bits for REGID) S 8
49、.6.1.1.4.3 Resignation request message N 8.6.1.1.4.4 Resignation confirmation message DEVICE_ID is replaced by NODE_ID and described in clause 9.3.1.2.2 of the current specification. The field size id expanded to 16 bits S 8.6.1.1.4.5 Forced resignation request message N 8.6.1.2 Admission via proxy MAP message are replaced by Beacon or skipped in beaconless mode S Domain in considered to be established if, and only if, there is a node operat
