信道相关对空间分集接收信号闪烁的影响

Influence of channel correlation on the signal scintillation with spatial diversity receiver

为了探究信道相关性对无线光通信中空间分集接收信号闪烁的影响,给采用空间分集接收技术的通信端的各子孔径大小与分布设计提供参考,理论推导了弱起伏条件下空间分集接收信道相关系数的表达式,给出了信道相关系数与分集接收信号闪烁的关系;数值研究了水平湍流均匀路径与整层大气湍流非均匀下行传输路径下的信道相关系数。结果表明,对于平面波,湍流非均匀路径下孔径接收时信道间存在明显的负相关特性。对于球面波,湍流非均匀路径下孔径接收时的信道相关性与湍流均匀路径情况类似,负相关特性都不明显。

In order to explore influence of channel correlation on the signal scintillation in free space communications system with spatial diversity receiver and provide references for design of the sub- aperture size and its distribution, the expression of channel correlation coefficient of spatial diversity receiver under weak fluctuation conditions was deduced in theory. The relationship between channel correlation coefficient and signal scintillation with spatial diversity receiver was obtained. Channel correlation coefficient under both horizontal uniform and whole layer download non-uniform turbulent propagation paths was numerically studied. For the plane wave, there is an obvious negative correlation property between sub-channels for aperture receiver under non-uniform turbulent propagation path. For the spherical wave, it is similar for both turbulent non-uniform path and uniform path for aperture receiver; the negative correlation properties are not obvious.