1、 INTERNATIONAL TELECOMMUNICATION UNION J.118TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (05/2000) SERIES J: TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDIA SIGNALS Interactive systems for digital television distribution Access systems for interactive services on SMATV/MATV netwo
2、rks ITU-T Recommendation J.118 (Formerly CCITT Recommendation) ITU-T J-SERIES RECOMMENDATIONS TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDIA SIGNALS General Recommendations J.1J.9 General specifications for analogue sound-programme transmission J.10J.19 Performance characteristics
3、of analogue sound-programme circuits J.20J.29 Equipment and lines used for analogue sound-programme circuits J.30J.39 Digital encoders for analogue sound-programme signals J.40J.49 Digital transmission of sound-programme signals J.50J.59 Circuits for analogue television transmission J.60J.69 Analogu
4、e television transmission over metallic lines and interconnection with radio-relay links J.70J.79 Digital transmission of television signals J.80J.89 Ancillary digital services for television transmission J.90J.99 Operational requirements and methods for television transmission J.100J.109 Interactiv
5、e systems for digital television distribution J.110J.129 Transport of MPEG-2 signals on packetised networks J.130J.139 Measurement of the quality of service J.140J.149 Digital television distribution through local subscriber networks J.150J.159 For further details, please refer to the list of ITU-T
6、Recommendations. ITU-T J.118 (05/2000) i ITU-T Recommendation J.118 Access systems for interactive services on SMATV/MATV networks Summary This Recommendation “Access systems for interactive services on SMATV/MATV networks“ covers the definition of the framing structure, channel coding and modulatio
7、n for the provision of an Interaction channel throughout SMATV/MATV networks from the user to the SMATV/MATV Head-end. This Recommendation defines two current technological alternatives for the interactive service provision in SMATV/MATV networks according to a bandwidth dependent classification. In
8、 particular, the cable based solution is fitted when broadband applications are concerned while the Master Link Low Rate TDMA is suited for narrow-band applications. Source ITU-T Recommendation J.118 was prepared by ITU-T Study Group 9 (1997-2000) and approved under the WTSC Resolution 1 procedure o
9、n 18 May 2000. ii ITU-T J.118 (05/2000) 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 responsible for studying techni
10、cal, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T study groups which,
11、 in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSC 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 IE
12、C. 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 attention to the possibility that the practice or implementation of this Recommendatio
13、n 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 the Recommendation development process. As of the date of approval of
14、 this Recommendation, ITU had not 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 latest information and are therefore strongly urged to consult the TSB patent
15、database. Ge3 ITU 2001 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from ITU. ITU-T J.118 (05/2000) iii CONTENTS Page 1 Scope. 1 2 Normative re
16、ferences 2 3 Abbreviations and relevant definitions . 2 4 SMATV/MATV Interactive system concepts. 4 5 Reference Model for system architecture of narrowband interaction channels in a broadcasting scenario (asymmetric interactive services) 5 5.1 Protocol Stack Model 5 5.2 System Model . 6 5.3 Applicat
17、ion of the Reference Model to the SMATV Interaction Channel . 6 6 Interaction Channel for SMATV/MATV systems 8 6.1 System description 8 6.2 Approach based on the “Cable solution“ 10 6.2.1 Spectrum allocation . 12 6.2.2 FDM/TDMA Multiple Access. 12 6.2.3 Bit rates and Framing. 13 6.3 Approach based o
18、n the “Master Link Solution or Low rate TDMA“ . 16 6.3.1 Main characteristics. 16 6.3.2 Physical Layer 17 6.3.3 Frequency Range . 18 6.3.4 Power Budget all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations
19、and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. 1 ITU-T J.84 (1997), Distribution of digital multi-programme signals for television, sound and data services through SMATV networks. 2 ITU-R BO.1211 (1995), Digital multi-programme emission
20、 systems for television, sound and data services for satellites operating in the 11/12 GHz frequency range. 3 ITU-T J.83 (1997), Digital multi-programme systems for television, sound and data services for cable distribution. 4 ITU-T J.112 (1998), Transmission systems for interactive cable television
21、 services. 5 ITU-T J.111 (1998), Network independent protocols for interactive systems. 6 ITU-T V.24 (2000), List of definitions for interchange circuits between data terminal equipment (DTE) and data circuit-terminating equipment (DCE). 7 ITU-T V.28 (1993), Electrical characteristics for unbalanced
22、 double-current interchange circuits. 8 ITU-T X.25 (1996), Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for terminals operating in the packet mode and connected to public data networks by dedicated circuit. 9 ISO 2110:1989, Information Technology Data
23、communication 25-pole DTE/DCE interface connector and contact number assignments. 10 ETSI EN 50201 (1998), Interfaces for DVB-IRD. 3 Abbreviations and relevant definitions 3.1 This Recommendation uses the following abbreviations: BC Broadcast Channel BIM Broadcast Interface Module CATV Cable TV dist
24、ribution system CDM Code Division Multiplex CTS Clear To Send DCE Data Communications Equipment DTE Data Terminal Equipment DVB Digital Video Broadcasting ETS European Telecommunications Standard IB In-Band ITU-T J.118 (05/2000) 3 IC Interaction Channel IIM Interactive Interface Module INA Interacti
25、ve Network Adapter IRD Integrated Receiver Decoder ISCM Interactive Services Commercial Module (DVB) ITU International Telecommunication Union ITU-R International Telecommunication Union Radiocommunication Sector ITU-T International Telecommunication Union Telecommunication Standardization Sector MA
26、C Media Access Control MATV Master Antenna Television MMDS Microwave Multipoint Distribution System MTU Maximum Transfer Unit NIU Network Interface Unit OOB Out of Band OSI Open Systems Interconnection PSTN Public Switched Telephone Network QAM Quadrature Amplitude Modulation QPSK Quaternary Phase S
27、hift Keying RTS Request to Send SLIP Serial Line Interconnection Protocol SMATV Satellite Master Antenna Television STB Set Top Box STU Set Top Unit TDM Time Division Multiplex TDMA Time Division Multiplex Access TS Transport Stream 3.2 The following relevant definitions are provided: 3.2.1 SMATV sy
28、stem A (SMATV-DTM): This system approach consists of the transmodulation from satellite Quaternary Phase Keying (QPSK) signals as defined in 2 to a Quadrature Amplitude Modulation (QAM) scheme as defined in 3. The process of transmodulation without baseband interfacing is also known as Transparent T
29、ransmodulation and the head-end unit performing this function is known as Transparent Digital Transmodulator (TDT). 3.2.2 SMATV system B: This system is based on the use of QPSK modulation. The SMATV system B concept allows a direct reception of digital satellite signals using frequency conversion o
30、f the received satellite signal to a frequency band appropriate to the characteristics of the SMATV distribution network. The functional elements of this system are given in the baseline satellite specification provided in 2. Two configurations of SMATV system B are considered as follows: SMATV-IF:
31、which uses the Intermediate Frequency (IF) as delivered by the Low Noise Block (LNB) (e.g. 950-2150 MHz) SMATV-S: which uses a conversion to the extended S band (e.g. 230-470 MHz). 4 ITU-T J.118 (05/2000) 3.2.3 SMATV grouping terminal or interactive head-end: The Grouping Terminal at the SMATV perfo
32、rms the collection and the distribution of information coming from and going to the user terminals. It is composed by the Grouping Terminal Interactive Network Adapter (INA), the MAC functions and the interfaces with the other networks in order to collect/distribute the information in the SMATV coax
33、 network related to each user terminal (Interactive Interface Module IIM). 4 SMATV/MATV Interactive system concepts The Satellite Master Antenna Television (SMATV/MATV) system was previously intended for distribution of television and sound signals to households located in one or more adjacent build
34、ings. However, the advent of new digital interactive services implies that the SMATV/MATV networks should be equipped with a return channel allowing the introduction of digital interactive services. This kind of network is also known as community antenna installations or domestic TV cable networks.
35、A SMATV system represents a mean of sharing the same resources among several users for the Transmission/reception of contents. This Recommendation provides reference examples for the implementation of an interaction channel system to cope with two different scenarios. Scenario A) An environment of a
36、symmetric interactive services supporting broadcast to home with narrowband return channel. This is the typical broadcasting scenario enhanced with low capacity interactive services, the implementation of which is foreseen to be widespread within a short period of time. Scenario B) An environment or
37、iented towards wideband Multimedia services where the SMATV/MATV interconnection infrastructure can play a very effective role. The generic ITU Reference model for interactive systems described in ITU-T J.110 has been followed by the system described in this Recommendation. The Interaction Network i
38、s split into a supporting network, a coaxial section and an interface in-between. The SMATV/MATV section provides the two-way communications between each user Terminal and the SMATV/MATV head-end, which is located on the roof of each building. The interactive SMATV/MATV systems described in this Rec
39、ommendation propose solutions for bidirectional communications between the user and the SMATV/MATV head-end. The system consists of two main components: the Interactive Head-end or Grouping Terminal and the SMATV/MATV Interactive Interface Module or user terminal. Freedom is given for any further ne
40、twork connection at the head-end to link with the Service Provider. Solutions for the interconnection are being developed by other ITU Study Groups assuming either a wireless or wired solutions (satellite, terrestrial, CATV, etc.) The Interactive SMATV/MATV head-end performs the collection and the d
41、istribution of information coming from and going to the user terminals. It is composed of the Grouping Terminal Interactive Network Adapter or Interactive Head-end Network Adapter (INA), the MAC functions and the interfaces with other networks in order to collect/distribute the information in the SM
42、ATV/MATV coaxial network related to each user terminal (Interactive Interface Module IIM). For the SMATV/MATV section two approaches are proposed according to a bandwidth dependent classification. For wideband applications, a subset of the options provided for cable systems 4 is recommended (see 6.2
43、) allowing a system simpler than the CATV one, thus matching the requirements of the SMATV/MATV scenario. One of the key aspects of the SMATV/MATV scenario with respect to the CATV one is that the Grouping Terminal at the SMATV/MATV head-end should be a consumer equipment in a similar way as the Set
44、 Top Box, although the SMATV/MATV head-end cost is shared among the users connected to the same SMATV/MATV network. For narrowband applications the approach based on the Master Link system is recommended (see 6.3). ITU-T J.118 (05/2000) 5 The system described here is compatible with the ITU-T Networ
45、k Independent Protocols specification for Interactive services 5. The system described in this Recommendation is an open system allowing the interoperability with other networks irrespective of the technology supported. Guidelines are provided in this sense, allowing the use of alternative technolog
46、ies with the aim to allow the users or operators to select the technology best suited for each situation depending on the type of network, required services, quality of services, number of users, traffic requirements, etc. The interface between the Coaxial section and the other networks is defined w
47、ith the aim of facilitating the interoperability between subsystems from different vendors and technologies. In principle a very low cost interface, RS-232 based, is recommended although alternative interfaces are identified in order to allow the use of existing equipment as well as to facilitate th
48、e provision of multimedia broadband applications as identified in scenario B above. 5 Reference Model for system architecture of narrowband interaction channels in a broadcasting scenario (asymmetric interactive services) A reference model for the system architecture of narrowband interaction channe
49、ls in a broadcasting scenario (asymmetric interactive services) is presented in this clause. 5.1 Protocol Stack Model For asymmetric interactive services supporting broadcast to the home with narrowband return channel, a simple communications model consists of the following layers (the layers do not coincide exactly with the OSI layers). Physical layer: where all the physical (electrical) transmission parameters are defined. Transport layer: defines all the relevant data structures and communication protocols like data container
