Space-time Cooperative Coding Research In GEO Satellite Communication

Geostationary Earth Orbit（GEO） satellite has become an important tool in global remotecommunication. And GEO satellite communication plays a more and more important role in mobilecommunication in some fields like terrestrial communication, maritime communication, and spacecommunication. For GEO satellite communication, the distance between satellites and the earth isso long that the electromagnetic waves have to suffer the impact of different types of fading, Theuser downlink of GEO satellite communication is typical fading channel. If the signal transpondedby GEO satellites suffers a deep fading, then there will be a large range of distortion of the signalreceived by the receiver. Diversity technology is very effective in anti-fading among numerousresearches with excellent performance in terms of increasing transmission rate and improving biterror rate. As a typical application of diversity, cooperative communication has been attracted awide spread attention which means to share the single antenna of each terminal to be a virtualMultiple Input Multiple Output （MIMO） system without increasing device complexity andequipment numbers. It’s a very good candidate for GEO satellite whose weight and volume islimited to implement MIMO system.This paper introduces the space time cooperative technology into GEO satellitecommunication in consideration of the characteristics of GEO satellite communication. The maincontents of this paper include the following aspects: firstly, it outlines the characteristics of satellitechannel and space-time cooperative technology; then, referring to the terrestrial cooperativecommunication system, it introduces the space-time cooperative technology into GEO satellitecommunication in user downlinks, and proposes a cooperative system model base on two GEOsatellites, it’s assumed that the system is perfectly synchronous,and get the BER performance of2×1system and2×2system by using simple space-time block code. At last it considers anasynchronous scenario for GEO cooperative communication, and introduces some delay-tolerantspace-time codes, highlights a novel design based on the concatenation of space-time code matrices,and implements it by using Golden code. Simulation results show the BER performance isimproved by using delay-tolerant space-time codes in asynchronous scenario, and the newconstruction method by Golden code outperforms than others.