孔径平均对自由空间光通信误码率的影响

Impact of Aperture Averaging on Bit-Error Rate for Free-Space Optical Communication

研究了接收端孔径平均效应对自由空间光通信误码率的影响。对数辐射方差是反映接收孔径上某一点闪烁起伏的参量。如果自由空间光通信的误码率仅仅是和对数辐射方差有关,那么得到的就是点接收器的结果。对数辐射的协方差是与接收平面上某两点间距离有关的闪烁起伏参量。孔径平均效应意味着要将误码率和对数辐射的协方差联系起来。文中共考虑了两种模型:球面波和平面波,并假设接收孔径直径等于第一菲涅耳区尺度。分析的结果显示,孔径平均后的误码率有明显的减小。

In free-space optical communication, the impact of aperture averaging of the receiver on the bit-error rate is studied. The log-irradiance variance is a parameter that reflects the log-intensity fluctuation of a certain point on the receiving aperture. If the bit-error rate solely depends on log-irradiance variance, the result is just for the instance of point receiver. The covariance of log-irradiance is a parameter which is fluctuating related to the spacing between two points at the receiver plane. The aperture averaging effect connects the bit-error rate and covariance of log-irradiance. Two kinds of models are considered, spherical wave and plane wave, and the diameter of the receiving aperture is supposed as the first Fresnel zone length. The result shows that the bit-error rate decreases significantly when the aperture averaging effect is taken into account.