增量选择解码前传中继系统的二阶统计特性

The second order statistics of incremental selection decode-and-forward relay system

针对解码中继系统由中继译码错误产生的系统性能降低以及频谱利用率低的问题,提出选择中继和增量中继相结合的增量选择解码前传(Incremental selection decode-and-forward,ISDF)中继系统,并且研究ISDF系统的中断性能,分析系统的二阶统计特性(平均电平通过率和平均中断时间)。在Nakagami-m衰落信道下,给出ISDF中继系统的中断概率、平均电平通过率和平均中断时间的闭合表达式。将ISDF系统与选择解码中继系统进行比较。研究结果表明:ISDF系统明显地提高了系统的性能,降低了中断概率;当切换门限和中断门限相等时,中断性能最优;ISDF系统的平均电平通过率和平均中断时间依赖于切换门限与中断门限的选择;ISDF系统性能受到源到中继链路和中继到目的地链路中较差的链路所限制。

Aiming at the problems of the fixed decode-and-forward relay system,incremental selective decode-and-forward（ISDF） relay system was proposed,which was composed of incremental relaying（IR） and selection relaying（SR）.The outage and the second order statistics（the average level crossing rate and the average output duration） of the ISDF relay system were analyzed.Closed-form expressions for the outage probability,the average level crossing rate and the average output duration were given.The results show that the ISDF relay system significantly improves outage performance in comparison with the SR protocol.The outage performance is optimal when the switching threshold is the same as outage threshold.The average level crossing rate and the average output duration are highly dependent on the switching threshold and outage threshold.The performance of the ISDF system depends on the worst of the source-relay channel and the relay-destination channel.