Satellite communication systems for domestic/business services

Abstract

AbstractThis paper is composed of two parts.The first part addresses some topics associated to the implementation of FDMA/TDM systems for ‘business’ services applications, operating at Ka band.A modular regenerative and processing satellite repeater, each module capable of handling up to 16 up‐link carriers in the 2 Mb/s range is considered. Available coding techniques were reviewed; concatenated codes seem highly interesting because of the high coding gains achievable with two simpler co‐decoding processes in series, and also because they lead to an implementation wherein the internal coder is installed on board the satellite, while the external one is installed in the user terminals.The problem of keeping stable the up‐link carriers in the satellite demodulators is discussed and a compensation method is proposed.Finally, simulation results of co‐decoding and carrier extraction performance are illustrated.The second part concerns the implementation of a multifrequency TDMA system. This is a hybrid system whereby the access for up‐links uses time and frequency slots in a time‐frequency map. The adoption of a clock synchronous network allows a frame for which no preamble and guard time are inserted between the burst.The error contributions and the performance of the clock synchronous network are assessed. A solution to the problem of fast phase/frequency estimation is proposed.For a clock synchronous network fast algorithms suitable for frequency demultiplexing and detecting of the FDM signal could be adopted; a modular solution to the implementation of the demultiplexer and detector is proposed based on the use of an optimized matched filter; a multistage scheme minimizes the number of multiplications.