大气湍流引起的光强起伏是影响激光通信系统接收信噪比和误码率的主要因素。文中旨在研究大气湍流状态对无线通信系统性能的影响。首先利用对数正态分布和Gamma-Gamma分布分别对信道进行建模,分析表明前者不适用于中强湍流下的光强起伏行为,而后者具有更广的应用范围。在此基础上,研究相位噪声对系统接收信噪比和误码率的影响。文中最后在不同信道条件下进行仿真实验,观察光强起伏方差引起的星座图变化和误码率恶化情况。实验结果表明,当光强起伏方差逐渐增大时,星座图相位角度和误码率均随之变大。文中的分析与讨论对提高激光通信质量具有一定的参考价值。

The irradiance fluctuation induced by atmospheric turbulence is a major factor to degrade the Signal-to-Noise Ratio (SNR) and bit error rate (BER) of laser communication systems. This paper aims to explore the effect of atmospheric turbulence state on the performance of wireless communication systems. Firstly, the channel was modeled by the logarithmic normal distribution and Gamma-Gamma distribution, respectively. Analysis showed lights on that the former model was not fit for irradiance fluctuation behavior in moderate or strong turbulent conditions, while the latter had wider applications. On this basis, the SNR and BER resulting from the phase noise introduced by irradiance were studied. Simulations were conducted for different channel models, which displayed the change of planisphere and degradation of BER along with irradiance variance. Results illustrates that the phase angle of planisphere and BER increase when the irradiance variance becomes larger. Up to a point, these discussions are valuable for real optical communication applications.