1、INTERNATIONAL TELECOMMUN CATION UN ION ITUmT TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU J.150 Amendment 2 (03/200 I ) SERIES J: CABLE NETWORKS AND TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDIA SIGNALS Digital television distribution through local subscriber networks Operation
2、al functionalities for the delivery of digital multiprogramme television, sound and data services through multichannel, multipoint distribution systems (MMDS) Amendment 2 ITU-T Recommendation J.150 - Amendment 2 (Formerly CCITT Recommendation) INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNIC
3、ATION STANDARDIZATION SECTOR OF ITU JA50 Amendment 2 (031200 1 ) SERIES J: CABLE NETWORKS AND TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDIA SIGNALS Digital television distribution through local subscriber networks Operational functionalities for the delivery of digital multiprogra
4、mme television, sound and data services through multichannel, multipoint distribution systems (MMDS) Amendment 2 ITU-T Recommendation J. 150 - Amendment 2 (Formerly CCITT Recommendation) ITU-T J-SERIES RECOMMENDATIONS CABLE NETWORKS AND TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDI
5、A SIGNALS General Recommendations J. 1-J.9 General specifications for analogue sound-programme transmission 5.10-J.19 Performance characteristics of analogue sound-programme circuits J.20-J.29 Equipment and lines used for analogue sound-programme circuits J.30-J.39 Digital encoders for analogue soun
6、d-programme signals J.40-J.49 Digital transmission of sound-programme signals J.50-J.59 Circuits for analogue television transmission 5.60-5.69 Analogue television transmission over metallic lines and interconnection with radio-relay links 5.70-5.79 Digital transmission of television signals 5.80-5.
7、89 Ancillary digital services for television transmission J.90-J.99 Operational requirements and methods for television transmission J. 100-5.109 Interactive systems for digital television distribution J. 1 10-J. 129 Transport of WEG-2 signals on packetised networks J. 130-J. 139 Measurement of the
8、quality of service J. 140-5.149 Dbl Framing structure, channel coding and modulation for digital terrestrial television. 2) Clause 5 In abbreviations and acronyms add the following acronym in alphabetical order: OFDM Orthogonal Frequency Division Multiplexing 3) Clause A.l At the end of this clause
9、add the followingparagraph: Another variant of System A is an optional MMDSMVDSLMDS system using OFDM modulation; its specifications are derived from the DVB-T standard ETSI EN 300 7441 with additional details that apply to multi-programme microwave services. Consequently there is now the option of
10、adopting the benefits of OFDM modulation for microwave transmission in any frequency band. 4) Clause A.2 Add a new clause A.2.3 as follows: A.2.3 MMDWOFDM system concept The MMDS/OFDM system shall be defined as the functional block of equipment performing the adaptation of the baseband TV signals to
11、 the MMDS/OFDM channel characteristics (see Figure A.3). At the transmitter site, the following TV baseband signal source can be considered: - satellite signal(s); - cable signal(s); - contribution link(s); - local program source(s). ITU-T J.150/Amd.2 (03/2001) 1 Microwave Transport down-converters
12、Baseline Svstem Demodulator/ - 1 Decoder 1 1 UVO-I signai II Il J TO91014oM) Figure A.3/J.150 - Functional block diagrams of the baseline and transport systems The baseline system is defined as the functional block of equipment performing the adaptation of the baseband TV signals from the output of
13、the WEG-2 transport multiplexer, to the UHFNHF channel characteristics. The following processes are applied to the data stream (see Figure A.3): - transport multiplex adaptation and randomization for energy dispersal; - outer encoding (i.e. Reed-Solomon encoding); - outer interleaving (i.e. convolut
14、ional interleaving); - inner encoding (i.e. punctured convolutional code); - inner interleaving; - mapping and modulation; - The system is directly compatible with WEG-2 coded TV signals ISO/IEC 13818. This baseline system is covered in detail in the DIB-T specification ETSI EN 300 7441: Digital Vid
15、eo Broadcasting (DVB); Framing structure, channel coding and modulation for digital terrestrial television. The Microwave DVB-T Transport System MMDS/OFDM VB-MT) uses the same modulation characteristics as the Terrestrial Baseline System but frequency translates it to a microwave transport layer as
16、can be seen in Figure A.3. It can then be frequency translated back to the v“F band where it is compatible with the Terrestrial Baseline DVB-T demodulators and decoders. Orthogonal Frequency Division Multiplexing (OFDM) transmission. 2 ITU-T J.150/Amd.2 (03/2001) SERIES OF ITU-T RECOMMENDATIONS Seri
17、es A Series B Series C Series D Series E Series F Series G Series H Series I Series J Series K Series L Series M Series N Series O Series P Series Q Series R Series S Series T Series U Series V Series X Series Y Series Z Organization of the work of ITU-T Means of expression: definitions, symbols, cl
18、assification General telecommunication statistics General tariff principles Overall network operation, telephone service, service operation and human factors Non-telephone telecommunication services Transmission systems and media, digital systems and networks Audiovisual and multimedia systems Integ
19、rated services digital network Cable networks and transmission of television, sound programme and other multimedia signais Protection against interference Construction, installation and protection of cables and other elements of outside plant TMN and network maintenance: international transmission s
20、ystems, telephone circuits, telegraphy, facsimile and leased circuits Maintenance: international sound programme and television transmission circuits Specifications of measuring equipment Telephone transmission quality, telephone installations, local line networks Switching and signalling Telegraph
21、trammission Telegraph services terminal equipment Terminals for telematic services Telegraph switching Data communication over the telephone network Data networks and open system communications Global information infiastructure and Internet protocol aspects Languages and general software aspects for telecommunication systems Printed in Switzerland Geneva, 2001
