无线激光通信大气信道性能分析

发布时间：2018-06-13 00:31

本文选题：无线激光通信 + 衰减　；参考：《西安电子科技大学》2014年硕士论文

【摘要】：自由空间光通信（无线激光通信）具有抗干扰能力强、信息容量大等众多优点，而大气环境是影响其传输的最主要的原因之一，无线光通信信道特性研究也是至关重要的。本文首先首先研究了各种大气粒子造成的衰减效应，分别讨论了激光在对流层大气传输中，气溶胶、云雾、降雨、大气湍流等引起的大气衰减效应，预测了不同能见度的云雾引起的不同波长激光能量的衰减。结果表明，云雾的衰减一般比气溶胶的大，随能见度的降低增加快。其次，利用通信系统中的信噪比和误码率模型，计算分析了各种情况下的信噪比和误码率，，并利用OOK、DPSK、PSK、PPM等调制解调技术来改善光通信系统性能，得出采用PPM调制改善系统性能最具优势。然后，应用给出的闪烁指数模型分别预测了不同湍流强度、不同路径天顶角及不同波束半径下闪烁指数的结果，进一步分析了，在地-空路径下，考虑大气湍流影响情况下的系统信道容量和中断概率。通过仿真计算分析了在对数正态分布和Gamma-Gamma分布下平均容量和中断概率的变化趋势。最后，从大气信道方面介绍了提高无线光通信系统性能的有效方法，对未来的发展和研究具有一定的指导意义。
[Abstract]:Free space optical communication (wireless laser communication) has many advantages, such as strong anti-jamming ability, large information capacity and so on. The atmospheric environment is one of the most important factors affecting its transmission, and the research on the channel characteristics of wireless optical communication is also very important. In this paper, the attenuation effects caused by various atmospheric particles are studied, and the atmospheric attenuation effects caused by aerosols, clouds, rainfall and atmospheric turbulence in the tropospheric atmosphere are discussed respectively. The attenuation of laser energy at different wavelengths caused by cloud and fog with different visibility is predicted. The results show that the attenuation of cloud and mist is larger than that of aerosol and increases with the decrease of visibility. Secondly, the signal-to-noise ratio (SNR) and bit error rate (BER) model of the communication system are used to calculate and analyze the SNR and BER in various cases, and the modulation and demodulation techniques such as OOKO / DPSK / PSKPPM are used to improve the performance of the optical communication system. It is concluded that using PPM modulation to improve the performance of the system has the most advantages. Then, the scintillation exponent model is applied to predict the scintillation exponents under different turbulence intensity, different path zenith angle and different beam radius respectively. The channel capacity and interruption probability of the system under the influence of atmospheric turbulence are considered. The variation trend of average capacity and outage probability under logarithmic normal distribution and Gamma-Gamma distribution is analyzed by simulation. Finally, an effective method to improve the performance of wireless optical communication system is introduced from the aspect of atmospheric channel, which has a certain guiding significance for the future development and research.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.12

【参考文献】