1、 International Telecommunication Union ITU-T J.222.1TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (07/2007) SERIES J: CABLE NETWORKS AND TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDIA SIGNALS Interactive systems for digital television distribution Third-generation transmission sy
2、stems for interactive cable television services IP cable modems: Physical layer specification ITU-T Recommendation J.222.1 ITU-T Rec. J.222.1 (07/2007) i ITU-T Recommendation J.222.1 Third-generation transmission systems for interactive cable television services IP cable modems: Physical layer speci
3、fication Summary ITU-T Recommendation J.222.1 defines the electrical characteristics and signal processing operations for a cable modem (CM) and cable modem termination system (CMTS) over third generation high-speed data-over-cable systems. This Recommendation defines physical layer requirements tha
4、t support the channel bonding operations defined in ITU-T Recommendation J.222.2. Source ITU-T Recommendation J.222.1 was approved on 29 July 2007 by ITU-T Study Group 9 (2005-2008) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. J.222.1 (07/2007) FOREWORD The International Telecommunica
5、tion 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 responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a v
6、iew 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-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommend
7、ations 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 basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for concis
8、eness to indicate 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 Recommendatio
9、n 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 use of such words does not suggest that compliance with the Recommendation is required of any party. INT
10、ELLECTUAL 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 no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights,
11、whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers ar
12、e cautioned that this 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 2008 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permissi
13、on of ITU. ITU-T Rec. J.222.1 (07/2007) iii CONTENTS Page 1 Scope 1 1.1 Introduction and purpose 1 1.2 Background. 1 2 References. 5 2.1 Normative references 5 2.2 Informative references 5 2.3 Reference acquisition . 6 3 Definitions 6 4 Abbreviations, acronyms and conventions. 8 4.1 Abbreviations an
14、d acronyms 8 4.2 Conventions 11 5 Functional assumptions 11 5.1 Equipment assumptions 12 5.2 RF channel assumptions. 12 5.3 Transmission levels 14 5.4 Frequency inversion . 14 6 Physical media dependent sublayer specification. 14 6.1 Scope 14 6.2 Upstream. 15 6.3 Downstream 86 Annex A Timing require
15、ments for supporting business services over DOCSIS 93 A.1 CMTS . 93 A.2 CM 93 Annex B Additions and modifications for 8 MHz channel spacing . 94 B.1 Scope 94 B.2 References 95 B.3 Terms and definitions. 95 B.4 Abbreviations and acronyms 95 B.5 Functional assumptions 96 B.6 Physical media dependent s
16、ublayer specification 99 Annex C MPEG header synchronization and recovery 131 C.1 MPEG header synchronization and recovery in the North American technology option . 131 C.2 MPEG header synchronization and recovery in the European technology option 131 iv ITU-T Rec. J.222.1 (07/2007) Page Annex D Jap
17、an specification additions. 132 D.1 Scope 132 D.2 References 132 D.3 Terms and definitions. 132 D.4 Abbreviations, acronyms and conventions. 132 D.5 Functional assumptions 132 D.6 Physical media dependent sublayer specification 136 Appendix I Example preamble sequence 160 I.1 Introduction 160 I.2 Ex
18、ample preamble sequence 160 Appendix II S-CDMA framing. 162 II.1 Coded subsymbol numbering. 162 II.2 Uncoded subsymbol numbering. 162 II.3 Framer output numbering. 163 II.4 Comments. 163 Appendix III Ambient temperature and wind loading effects 164 III.1 Synchronization tolerances to plant delay var
19、iations . 164 III.2 Change in propagation delay due to temperature changes . 165 Appendix IV Description of upstream transmit channel set capability: Example calculations for reporting and figuring the number of active channels supported . 167 Appendix V Description of upstream channel power control
20、 with multiple upstream channels 169 V.1 DOCSIS 2.0 parameters extended to multiple transmit channel mode 169 V.2 New parameters in DOCSIS 3.0 upstream power control (“loading“, Pload_n, Pload_min_set, Dynamic Range Window, Plow_multi_n) 169 V.3 Example upstream power control with multiple transmit
21、channel mode enabled 170 V.4 Examples regarding concurrent and cnsecutive changes in Pr_nand Pload_min_set. 172 Appendix VI Example spurious emissions noise power limits with multiple channels bursting . 175 ITU-T Rec. J.222.1 (07/2007) 1 ITU-T Recommendation J.222.1 Third-generation transmission sy
22、stems for interactive cable television services IP cable modems: Physical layer specification 1 Scope 1.1 Introduction and purpose This Recommendation defines the physical layer requirements as part of a series of Recommendations that define the third generation of high-speed data-over-cable system.
23、 This Recommendation defines physical layer requirements that support the channel bonding operations defined in ITU-T J.222.2. There are differences in the cable spectrum planning practices adopted for different networks in the world. Therefore, three options for physical layer technology are includ
24、ed, which have equal priority and are not required to be interoperable. The first technology option is based on the downstream multi-programme television distribution that is using 6 MHz channelling and modulation as per ITU-T J.83-B, the second option is for use where 8 MHz channel spacing and modu
25、lation as per ETSI EN 300 429 is used, the third option is for use where 6 MHz channel spacing and modulation as per ITU-T J.83-C is used. The first and second technology options share a common set of choices for upstream symbol rate, while the third technology option provides a different set. All o
26、ptions have the same status, notwithstanding that the document structure does not reflect this equal priority. The first of these options is defined in clauses 5 and 6, whereas the second is defined by replacing the content of those clauses with the content of Annex B, and the third is defined by re
27、placing the content of those clauses with the content of Annex D. Correspondingly, ITU-T J.83-B and CEA-542-B apply only to the first option, ETSI EN 300 429 only to the second, and ITU-T J.83-C only to the third. Compliance with this Recommendation requires compliance with one of these implementati
28、ons, not with all. It is not required that equipment built to one option shall interoperate with equipment built to either of the others. These optional physical-layer technologies allow operators flexibility in mandated areas of operation, including any frequency planning, EMC (electromagnetic comp
29、atibility), and safety requirements. For example, the 6 MHz downstream based option defined in clauses 5 and 6 might be deployable within an 8 MHz channel plan. Compliance with frequency planning and EMC requirements is not covered by this Recommendation and remains the operators responsibility. Bac
30、kwards compatibility with earlier versions of this technology ITU-T J.122 is only ensured within the same technology option referred to above and not between the different technology options. 1.2 Background 1.2.1 Broadband access network A coaxial-based broadband access network is assumed. This may
31、take the form of either an all-coax or hybrid-fibre/coax (HFC) network. The generic term “cable network“ is used here to cover all cases. 2 ITU-T Rec. J.222.1 (07/2007) A cable network uses a tree-and-branch architecture with analog transmission. The key functional characteristics assumed in this Re
32、commendation are the following: Two-way transmission. A maximum optical/electrical spacing between the cable modem termination system (CMTS) and the most distant cable modem (CM) of 100 miles in each direction, although typical maximum separation may be 10-15 miles. A maximum differential optical/el
33、ectrical spacing between the CMTS and the closest and most distant modems of 100 miles in each direction, although this would typically be limited to 15 miles. At a propagation velocity in fibre of approximately 1.5 ns/ft, 100 miles of fibre in each direction results in a round-trip delay of approxi
34、mately 1.6 ms. 1.2.2 Network and system architecture 1.2.2.1 The DOCSIS network The elements that participate in the provisioning of DOCSIS services are shown in Figure 1-1: J.222.1(07)_F1-1ProvisioningsystemsIPv4CPEBack office network HFC network Home networkCMTSCMCMNMSHFCIPv6CPEIPv4CPEIPv6CPEFigur
35、e 1-1 The DOCSIS network The CM connects to the operators HFC network and to a home network, bridging packets between them. Many CPE devices can connect to the CMs LAN interfaces. CPE devices can be embedded with the CM in a single device, or they can be separate standalone devices, as shown in Figu
36、re 1-1. CPE devices may use IPv4, IPv6 or both forms of IP addressing. Examples of typical CPE devices are home routers, set-top devices, personal computers, etc. The CMTS connects the operators back office and core network with the HFC network. Its main function is to forward packets between these
37、two domains, and between upstream and downstream channels on the HFC network. Various applications are used to provide back office configuration and other support to the devices on the DOCSIS network. These applications use IPv4 and/or IPv6 as appropriate to the particular operators deployment. The
38、following applications include: Provisioning systems The DHCP servers provide the CM with initial configuration information, including the device IP address(es), when the CM boots. ITU-T Rec. J.222.1 (07/2007) 3 The Config File server is used to download configuration files to CMs when they boot. Co
39、nfiguration files are in binary format and permit the configuration of the CMs parameters. The Config File server is also used to download software upgrades to the CM. The time protocol server provides time protocol clients, typically CMs, with the current time of day. Certificate Revocation server
40、provides certificate status. Network management system (NMS) The SNMP manager allows the operator to configure and monitor SNMP agents, typically the CM and the CMTS. The Syslog server collects messages pertaining to the operation of devices. The IPDR collector server allows the operator to collect
41、bulk statistics in an efficient manner. 1.2.3 Service goals As cable operators have widely deployed high-speed data services on cable television systems, the demand for bandwidth has increased. Additionally, networks have scaled to such a degree that IPv4 address constraints are becoming a burden on
42、 network operations. It is thus appropriate to add new features to the DOCSIS Recommendations for the purpose of increasing channel capacity, enhancing network security, expanding addressability of network elements, and deploying new service offerings. The DOCSIS system allows transparent bidirectio
43、nal transfer of Internet protocol (IP) traffic, between the cable system head-end and customer locations, over an all-coaxial or hybrid-fibre/coax (HFC) cable network. This is shown in simplified form in Figure 1-2. J.222.1(07)_F1-2Figure 1-2 Transparent IP traffic through the data-over-cable system
44、 1.2.4 Statement of compatibility This Recommendation specifies an interface, commonly referred to as DOCSIS 3.0, which is the third generation of the interface, commonly referred to as DOCSIS 1.x and 2.0. DOCSIS 3.0 MUST be backward- and forward-compatible with equipment built to the previous Recom
45、mendations. DOCSIS 3.0-compliant CMs MUST interoperate seamlessly with DOCSIS 2.0 and DOCSIS 1.x CMTSs, albeit in the 2.0 and 1.x modes, as the case may be. DOCSIS 3.0-compliant CMTSs MUST seamlessly support DOCSIS 2.0 and DOCSIS 1.x CMs. 1.2.5 Reference architecture The reference architecture for d
46、ata-over-cable services and interfaces is shown in Figure 1-3. 4 ITU-T Rec. J.222.1 (07/2007) J.222.1(07)_F1-3FibrenodeM-CMTScoreEQAMUpstreamreceiverDOCSIS timing serverWide areanetworkNetwork sideinterface (NSI)Operations support systems interface(OSSI)Cable modem to CPEinterface(CMCI)Downstreamext
47、ernal-phyinterface (DEPI)DOCSIS timinginterface (DTI)Edge resourcemanagementinterfaces(ERMI)Downstream RF interface(DRFI)Cablemodem(CM)Operations support systemEdgeresourcemanagerPhysical layerinterface(PHY)DownstreamRFnetworkUpstreamRFnetworkOpt.TxM-CMTSI-CMTSDistribution hub or headendCoaxdistribu
48、tionFibredistributionNOTE Lighter shaded areas are related functionality, but out of the scope of this Recommendation. Customer premisesequipmentMAC users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and oth
49、er references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T H.222.0 ITU-T Recommendation H.222.0 (2006) | ISO/IEC 13818-1:2007, Information technology Generic coding of moving pictures and associated audio information: Systems. ITU-T J.83-B Annex B to ITU-T Recommendation J.83 (1997), Digital multi-programme systems for televi
