针对使用定向天线的协作通信系统,对固定译码转发协议(decode-and-forward protocol,DF)的误符号率(symbol error rate,SER)性能进行探索性研究。首先建立了基于定向天线的 DF 协作通信系统模型,从理论上推导出该模型下的 SER 闭式表达式,确定 SER 上界,并以 SER 为优化目标分析最优功率分配问题,最后结合具体的数值仿真对所建立模型的 SER 性能进行详细分析比较。结果表明,在使用定向天线的条件下,DF 协作通信系统的 SER 更小,系统性能优劣与各节点定向增益、信道质量和功率分配方式密切相关,最优功率分配比平均功率分配性能更优。
Concerning the cooperative communication system based on directional antenna,the performance of the symbol error rate (SER)under the decode-and-forward protocol (DF)is studied.Firstly,a DF cooperative communication system model is established based on the directional antenna.Secondly,the closed-form expression of SER in the model is theoretically derived,and then the upper bound of the SER is determined.And the optimal power allocation problem is analyzed in order to optimize the SER performance.Finally,the performance of the SER is analyzed and compared combining with specific numerical simulation.The results show that in the condition of using the directional antenna,the DF cooperative communication system has smaller SER.The merits of system performance are closely related to directional gain,channel quality and power distribution of each node.The optimum power allocation has better performance than the average power allocation.