卫星通信中基于扩频技术的异步差分空时协同编码研究

卫星通信系统中, 经过不同信道的中继信号强度存在显著差异, 存在同步误差且时延差动态变化, 严重影响了误码性能. 传统方案一般通过引入差分编码解决卫星通信接收端的动态信道估计问题. 本文通过扩频系统中的正交码区分来自不同中继卫星的信号, 借助扩频码表提取各路信号后进行空时解码. 从仿真结果可知, 差分空时编码与扩频技术相结合能获得更好的误码率性能, 很好地解决了随机时延差问题, 使接收端无须对信道参数进行估计, 从而大幅降低其复杂度. 

Asynchronous Differential Space-time Block Codes Based on Spreading Techniques over Satellite Communication

In satellite cooperative communication system, delay errors caused by different delay between different channels with large scale relays brings loss of BER. Traditional solutions generally use differential codes to estimate channel parameters dynamically in the receiving end of a satellite communication system. In this paper, orthogonal codes in spread spectrum technique systems are used to distinguish signals from different relay satellites. In this paper, spread spectrum codes table is used to extract signals from different relay satellites, then to carry out a space-time decoding. As can be seen in simulation results, differential space-time blocks codes with spreading has a better BER than the one without spreading. It solves the problem of random delay, so that the receiving end of the channel should not to estimate channel parameter. The complexity of the receiving end is significantly reduced.