多天线深空中继通信系统的中断概率和信道容量

Outage Probability and Ergodic Capacity of Deep Space Communication with Relay Forwarding and Multiple Antenna Reception

中断概率和各态历经信道容量是分析深空通信系统性能的重要指标.针对深空通信系统中链路损耗大、时延长、频繁中断的问题,分析了多天线深空中继通信系统的中断概率和各态历经信道容量.根据深空通信环境的特点建立了基于独立不同分布瑞利衰落信道的系统模型,推导了单支路信噪比的精确表达式,进而给出了单支路接收信噪比的概率密度函数,并推导了在选择合并方式下系统中断概率的闭合解析式以及各态历经信道容量的近似表达式.通过对系统性能的仿真,验证了本文系统模型和理论分析的有效性.

Multiple antenna reception combined with relay forwarding is an effective way to overcome problems of large link loss, path delay and frequent interruption in a deep space communication system （DSCS）. Outage probability and ergodic capacity are important performance indexes in DSCS. To the authors＇ knowledge, performance of DSCS with multiple antenna reception and relay forwarding has not been reported. This paper analyzes outage probability and ergodic channel capacity for DSCS with multiple antenna reception and relay forwarding. Considering the characteristics of DSCS environment, we use independent non-identical （i.n.i.） Rayleigh distribution as a fading model for each branch channel including source-relay and relay-destination channels. Exact SNR expressions for a single source-relay-destination branch are derived. Based on the i.n.i. Rayleigh model, the probability density function of the received SNR in each branch channel is given. For large distances between receiving antennas, a selection combing strategy is used at the receiving end. A closed form expression of system outage probability and an approximate expression of system ergodic channel capacity are derived. Simulation shows validity of the theoretical analysis.