基于过时反馈的选择协同分集研究

Research on Selection Cooperation Diversity Based on Outdated Feedback

在无线协同通信系统中,由于信道的时变特性,导致中继选择和数据发送时的信道状态信息不同。针对该问题,对基于过时反馈的选择协同策略进行研究。介绍系统模型及基于过时反馈的中继选择过程,推导系统的中断概率闭式结果和高信噪比下的近似逼近结果,通过分集复用折中性能分析得出,过时信道状态信息导致系统的最大分集阶数为2。数值仿真结果验证了理论分析的正确性,并且得到中继选择时的信道状态信息与数据发送的信道状态信息稍有不同,其中断性能就会大大降低的结论。

Due to characteristics of time-varying channel in the wireless cooperative communication system,the Channel State Information（ CSI） at the time of relay selection may be different from that at the time of data transmission. Aiming at this problem,the selection cooperation with outdated feedback is investigated in this paper. First,the system model and the relay selection process with outdated feedback are introduced, and the closed-form result of outage probability and closed approximation in the high SNR regime are derived. By analyzing Diversity-multiplexing Tradeoff （ DMT ） , it obtains the maximum diversity order which is 2 when the CSI used in relay selection is outdated. Finally, numerical simulation results verify the correctness of theoretical analysis,and show the outage performance will be greatly reduced when the CSI at the time of relay selection is slightly different form it at the time of data transmission.