为了研究降雨对自由空间量子通信的影响, 根据雨滴分布谱和Mie散射理论, 研究了降雨强度对消光系数的影响, 提出了光量子衰减、信道容量与降雨强度的关系, 建立了信道生存函数、传输距离的计算模型, 并进行了系统性能参数的仿真。结果表明, 在忽略大气气溶胶等其他粒子影响的情况下, 当降雨强度为1.46 mm/h,传输距离为3 km时, 光量子衰减为初始能量的50%, 信道容量为0.2702, 信道生存函数为0.9122, 信道误码率为1.8×10-8。由此可见, 降雨对自由空间量子通信的信道容量、生存函数、误码率有不同程度的影响。因此, 为了提高自由空间量子通信的可靠性, 应根据降雨强度, 自适应调整通信系统的各项参数。

To figure out the effect of rainfall on the free space quantum communication, the effect of rainfall intensity on extinction coefficient is discussed based on the theory of the distribution of raindrops and the Mie scattering theory. The relationship between photon attenuation, channel capacity and rainfall intensity is proposed. The calculation model of channel survival function and transmission distance is established. And the performance parameters of the system are simulated. Simulation results show that, without considering the effect of atmospheric aerosol particles and other circumstances, when the rainfall intensity is 1.46 mm/h, the transmission distance is 3 km, the initial energy of the photon decreases to 50%, the channel capacity is 0.2702, the channel value of the survival function is 0.9122 and the error rate of channel is 1.8×10-8. Thus, the rainfall has different influences on the performance of free space quantum communication, including the cavity of the channel, the survival function and the error rate. Therefore, the parameters should be adjusted adaptively based on the rainfall intensity to improve the reliability of free space quantum communication.