沙尘信道下激光通信系统的性能分析

沙尘对激光信号的散射和吸收作用会引起激光信号的严重衰减,本文结合我国沙尘粒子的半径分布特征,在考虑含水影响的基础上,研究了沙尘对激光信号衰减特性的影响,得到了接收端信噪比的表达式;同时针对OOK调制,推导了沙尘天气下激光通信系统的误码率和信道容量。仿真分析了能见度、传输距离、含水量以及激光波长等因素对误码率和信道容量的影响。结果表明:随着含水量和传输距离的增大以及大气能见度的减小,系统的误码率会呈现出不断增大的趋势,而信道容量则呈现减小的趋势。在能见度为4 km的情况下,波长为1 550 nm、传输距离为1 km时系统的误码率可达10~(-2)数量级,且归一化信道容量为8.48 bps/Hz。

Performance Analysis of Laser Communication System Under Sand-dust Channel

The scattering and absorption caused by sand-dust channel will lead to serious attenuation of the laser signals. By considering the characteristics of the sand-dust particle radius distribution and the effects of sand-dust moisture content, the impact of sand-dust on the attenuation characteristics of laser signal is investigated and the expression of signal-to-noise ratio at the receiving end is proposed. Moreover, the bit error rate and channel capacity under sand-dust weather are deduced for the OOK modulation. Furthermore, the effects of atmospheric visibility, transmission distance, sand-dust moisture content and laser wavelength on the bit error rate and channel capacity are simulated. The results show that the channel capacity and system BER performance decrease with the increase of sand-dust moisture content, transmission distance and the decrease of atmospheric visibility. When the atmospheric visibility is 4 km, the system bit error rate achieves 10^-2 orders of magnitude with a wavelength of 1 550 nm and a transmission distance of 1 km and the normalized channel capacity is up to 8.48 bps/Hz.