放大转发协同通信中协同时机的选择与误码率性能分析  

The choice of cooperation opportunity and SER analysis in amplify-and-forward cooperative communications system

作　　者：石钧[1,2] 林霏[1,2] 路安琼[1] 刘泽民[1] 

机构地区：[1]北京邮电大学电信工程学院,北京100876 [2]山东轻工业学院电子信息与控制学院,山东济南250353

出　　处：《电路与系统学报》2010年第3期91-95,134,共6页Journal of Circuits and Systems

摘　　要：传统半双工放大转发(AF)协同通信无论信道状态如何,总是采用协同通信模式,在一定程度上降低了系统自由度的利用率。基于此,本文研究了"协同时机"的问题。首先以优化一个具有两用户的AF系统的遍历容量为目标,提出一种改进的放大转发方式(IAF),通过比较源-目的端与中继-目的端的瞬时信道增益来判定是否需要采用协同通信模式。然后推导给出IAF方式下系统误码差错性能的近似闭合表达式。最后,文章还比较了两种不同功率分配方案下IAF与AF方式的系统性能。理论分析和仿真结果表明,IAF方式在遍历容量和误码差错性能上均优于传统AF方式。Conventional half-duplex amplify-and-forward （AF） method always adopts cooperative communications model regardless the fading state of the channel, which makes insufficient use of the degrees of freedom of the system in a way. So, this paper discusses the problem about ＂when to cooperate＂. In order to optimize the ergodic capacity of a two-user AF cooperative communication system, an improved AF （IAF） method is first proposed. Whether the IAF method adopting the cooperative model or not bases on the comparison about the instantaneous channel gains of source-to-destination with that of relay-to-destination. And then the approximately closed-form symbol-error-rate （SER） is derived. Finally, the system performances used IAF method are compared with that of AF with different power allocation schemes. Theoretical analysis and simulation results show that the IAF outperforms the AF method both in ergodic capacity and SER performance.

关 键 词：协同通信 放大转发 协同时机 遍历容量 误码率 

分 类 号：TN929.5[电子电信—通信与信息系统]