大气湍流双广义Gamma分布光强闪烁序列模拟方法研究

Research on Simulating Method of Optical Intensity Scintillation Series with Double Generalized Gamma Distribution in Atmospheric Turbulence

自由空间光通信中,大气湍流引起的光强闪烁会严重影响通信性能。为了减缓湍流引起的闪烁效应,根据湍流引起光波闪烁的时域特性,给出了一种闪烁动态序列模拟方法,其统计特性可用于自由空间光通信对抗湍流效应的研究。利用一种新的可描述不同湍流强度下光强闪烁的统计模型—双广义伽马分布和大气湍流信道时间协方差函数,应用有色光谱非高斯信号产生算法,建立了可以反映接收光强动态特性的时间序列模型。在考虑光通信系统的瞄准误差时,分析了不同湍流强度下光强闪烁的时间序列模拟,与理论结果吻合较好,且给出了联合概率密度下的平均误码率公式。利用产生的时间序列,对通信系统中的平均误码率和中断概率进行分析。

In free-space optical communication system, the scintillation of optical intensity from atmospheric turbulence can seriously affect communication performance. In order to reduce the scintillation effect caused by turbulence,based on the time-domain characteristics of light intensity scintillation caused by turbulence,a simulation method which can generate dynamic scintillation series is presented. And its statistical characteristics can be used in the study of free-space optical communication against turbulence effects. In this paper,the time series model are established which can reflect the dynamic characteristics of the received optical intensity. The time series model combine double generalized Gamma distribution and the time signal covariance function of atmospheric turbulence by using generation algorithm of the nonGaussian colored spectrum signal. When the pointing error is considered in the optical communication system,the time series simulation of the light intensity scintillation under different turbulence conditions is analyzed,and the results are in agreement with the theoretical results. And the formula of average BER under joint probability density is given. The communication system average bit error rate and outage probability can be analyzed by the generated time series involved.