非对称信道下协作通信系统中断概率的研究

Outage probability for cooperative communication system with asymmetric channel

首先建立了非对称信道下协作系统的数学模型,考虑了源节点到目的节点的直通链路,利用特征函数法推导出协作系统的平均中断概率公式,通过仿真验证了该中断概率公式的精确性,理论和仿真都表明协作系统的中断概率和中继节点的个数、位置分布以及协作系统的功率分配因子有着密切关系,并且考虑源到目的节点的直通链路相对于不考虑直通链路的情况具有更高的性能增益;然后又在此公式基础上就协作系统中继节点的位置分布对最优功率分配因子的影响进行了仿真分析,并指出协作系统的最优功率分配因子受制于中继节点的位置分布情况。

Firstly, a mathematical model of cooperative system in asymmetric channel considering the link diversity gain between the source and destination was presented. An analytical expression of the average outage probability which was proved accurate by simulation was derived by using the method of characteristic function. Theory and simulation indicate that the outage probability of the cooperative system has a close relationship with the relays’ number, location and the power allocation ratio of the cooperative system and it makes higher performance gain to consider the direct link between the source and the destination. And then the effect of the relay nodes location for the optimal power allocation ratio was studied based on the mathematical model. The results show that the optimal power allocation ratio is limited by the re- lays’ locations.