交叉相关双路分集OAM湍流光信道接收信号模拟研究

Study on Simulation of Two Cross-Correlated Received Signals in Turbulent OAM Optical Diversity Channels

为了用蒙特卡洛方法评估空间分集轨道角动量(Orbital Angular Momentum,OAM)光通信系统性能,提出模拟生成无限长交叉相关双路分集OAM信道接收光信号的方法.根据推广的稀疏谱模型,生成双路交叉相关高斯随机样本序列;然后通过逆变换将上述生成的相关高斯随机样本序列映射为服从双Johnson SB分布的随机样本序列.通过模拟实验发现,该方法生成的双路信号样本序列的统计分布与双Johnson SB分布能很好地吻合,并且每路信号的自相关和双路信号之间的交叉相关均与所需目标值一致.该结果表明,提出的方法能够用于模拟受大气湍流扰动的空间分集OAM信道接收光信号.

Aiming at evaluating the performance of orbital angular momentum(OAM)optical communication sys⁃tems with spatial diversity by Monte Carlo methods,we propose a method to simulate two cross-correlated received optical signals with infinite duration in OAM diversity channels.Two cross-correlated Gaussian random sample sequences are gen⁃erated by use of generalized sparse spectrum model;subsequently,the Gaussian sequences are mapped into random sample sequences obeying the dual Johnson SB distribution by the inverse transformation.It is found from simulation experiments that the statistical distribution of the two simulated signal sample sequences is in excellent agreement with the dual Johnson SB distribution;meanwhile,the auto-correlation of each sequence and the cross-correlation between the two sequences are well consistent with the target value.The experimental results verify that the proposed method can be used to simulate the received optical signals in OAM spatial diversity channels distorted by atmospheric turbulence.