Advanced modulation and channel coding tecniques for digital HDTV via satellite in the 20 GHz range

摘要

Three advanced modulation and channel coding techniques, making use of soft-decision Viterbi decoding, are evaluated over a simulated satellite channel affected by noise and interference to assess the feasibility of Wide RF-band digital HDTV emission systems (W-HDTV) in the 20 GHz range, capable of providing near studio quality. These techniques are evaluated, for different bit-rates (i.e. 140, 105 and 70 MBit/s), in the context of a possible ‘common frequency allocation’ by the WARC 1992 of the frequency range 21.4-22 GHz. This would allow a very efficient use of the spectrum by assigning the overall bandwidth (on one or both polarisations) to all service areas. The systems are compared in terms of required C/N for high quality pictures and for service continuity, protection ratios and number of channels available in 600 MHz, using both polarisations (i.e. frequency reuse).