Aiming at the problem of low transmission rate and inadequate resource utilization for single relay cooperative communication system based on distributed Alamouti codes, an improved scheme of cooperative diversity based on distributed Alamouti codes is proposed. Based on the traditional scheme, in which the receiving terminal uses two signals from transmit phase and makes the maximal-ratio combining, the improved scheme stores and uses the signal sent by source node in broadcast phase, implements maximal-ratio combining and receiving of the three signals, thus improving the diversity gain. Simulation results indicate that under the Rayleigh fading channel, the required signal-to-noise ratio can be greatly reduced in the improved scheme as compared with that in the existing cooperative diversity scheme based on Alamouti codes.%针对基于Alamouti码的单中继协同通信系统中传输速率较低和资源利用不充分的问题,提出一种改进的分布式Alamouti码协同分集方案.在传统方案利用转发阶段两路信号最大比合并接收的基础上,该方案存储并利用广播阶段源节点发送的信号,将三路信号进行最大比合并接收,从而提高了分集增益.仿真结果表明,在Rayleigh衰落信道下,与现有的Alamouti码协同分集方案相比,该方案所需信噪比可以大幅降低.
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