1、QUESTION ITU-R 285/4*Digital broadcasting of multiple services and programmesin the broadcasting-satellite service(2009)The ITU Radiocommunication Assembly,consideringa) that means for improving the flexibility and efficiency of use of the radio-frequencyspectrum are continuously investigated;b) tha
2、t there have been significant developments in efficient modulation and channel codingtechniques, including but not limited to formats using QPSK and 8PSK modulation techniques;c) that advances in video and audio compression techniques have shown the practicality oftransmitting more than one televisi
3、on and/or audio and/or data service per satellite transponder;d) that the very nature of digital transmissions, and the recent significant advancements inmultiplexing techniques, enables the flexible and simultaneous transmission of a wide variety ofservices, digitally coded and systematically integ
4、rated, within any single satellite transponder usingsuch multi-service satellite broadcasting techniques;e) that video, audio, still-pictures, teletext, facsimile, and a variety of useful data services,including software distribution or interactive multimedia services, can be included in these type
5、ofbroadcasts;f) that the availability requirements of these different services can vary according to theirapplication;g) that broadcasting multimedia services will be widely introduced in the future,h) that the multiplexing of these services can be referred to as, inter alia, Integrated ServicesDigi
6、tal Broadcasting, or ISDB;j) that broadcasting-satellite channels provide an effective means for transmitting integrateddigital broadcasting services;k) that the transmission of multiple video, audio or data services per transponder reducesprogramme costs per channel, facilitates the increase in num
7、ber of services, and provides a moreattractive overall service;_* Former Question ITU-R 3/6.- 2 -l) that technological developments of large-scale integrated circuits, digital informationprocessing techniques, and bit-rate reduction techniques, especially for video and sound signals,facilitate the e
8、conomical implementation of multi-service satellite broadcasting systems to provideimproved broadcast services to the public;m) that multi-service satellite broadcasting systems are also used to serve professional cableand SMATV installations for further terrestrial distribution, and that a high deg
9、ree of harmonizationbetween digitally-coded signals used for satellite broadcasting and for radiocommunication servicesmay offer further advantages,decides that the following Questions should be studied1 What are suitable and/or optimal modulation and channel coding techniques for multi-service sate
10、llite broadcasting, what are practical channel transmission rates (capacity), and whatperformance is achievable (e.g. BER as a function of C/N and C/I)?2 What are appropriate availability performance requirements and bit error rate requirementsfor the transmission of these multi-service satellite br
11、oadcasting systems?3 What are appropriate error-correction coding and/or error-concealment processes thatoptimize quality, bandwidth and cost considerations?4 What protection ratios are required between two digital signals and between a digital signaland other types of signals likely to be transmitt
12、ed in the band allocated to the broadcasting-satelliteservice?5 What type of multiplexing structure is optimal for the flexible transport of multiple servicesin the satellite transponder? What type of multiplexing structure is optimal for the flexibletransmission of different types of services?6 Wha
13、t are the optimum satellite system parameters, such as digital transmission bit rate (andassociated channel coding, error-correction rate), to match the current performance of cablenetworks and SMATV installations?NOTE 1 See Report ITU-R BO.2008 and Recommendations ITU-R BO.1408 and ITU-R BO.1516,further decides1 that the results of the above studies should be included in appropriate Reports and/orRecommendations.2 that the above studies should be completed by 2011.Category: S1
