基于极化分集的DF机会中继协作通信系统性能分析

Performance Analysis of DF Opportunistic Relaying Cooperative Communication System with Polarization Diversity

提出对机会中继协作通信系统节点配置极化天线,实现节点到节点无线信号的极化分集,达到通过改善通信链路质量来提升DF机会中继协作通信系统整体性能的目的。由于电磁波信号在传播过程中经过地表及障碍物多次反射、折射、散射以及极化偏转,协作节点和目的节点配置的极化天线接收到的两路极化分集信号具有一定相关性和功率不平衡特性。研究了极化分集信号存在相关性和功率不平衡特性对机会中继协作通信系统性能的影响。结果表明,即使两路极化分集信号具有一定的相关性和功率不平衡特性,DF机会中继协作系统在相同信噪比和相同的信道衰落环境下,性能指标也优于未采用极化分集技术的DF机会中继协作通信系统。

The performance of a decode-and-forward opportunistic relaying protocol is analyzed with considering the small size terminals equipped with polarization antennas to realize the diversity gain at the same time to meet the constraints of the node volume. At every receiving node, the received polarization signals consist of two replicas of transmitted signal with fading amplitudes that are correlated random variables and have power unbalance. The obtained results show that the overall performance of DF opportunistic relaying cooperative communication system is improved by improving the quality of node-to-node communication link. Using polarization antennas, the same outage probability can be obtained with significantly lower SNR compared with the traditional system with no link diversity even if a certain level of correlation and power unbalance exists between the diversity branches.