基于准正交编码的MIMO空间光通信技术研究

摘要

由于自由空间光通信严重受到大气湍流引起的光强起伏,光束漂移等问题对通信性能的影响,本文研究了大气信道特性并分析了空时分组编码方案,采用MIMO技术提高自由空间光通信系统的性能.基于MIMO技术下的准正交编码方案不仅可以增强信道的抗衰落能力而且可以提供一定的分集增益和编码增益.在Matlab平台下使用蒙特卡罗模拟方法,对系统的信道容量和误码率进行数值研究.仿真结果表明:采用MIMO技术能够提高信道容量,有效改善误码性能,而且分集数越高,通信质量越好.%Due to the free space optical communication severely affected by atmospheric turbulence caused by intensity fluctuation, beam drift, this paper studies the characteristics of atmospheric channel and analyses the space-time block coding scheme, the MIMO technology can improves the performance of free space optical communication system. The orthogonal coding scheme based on MIMO technology can not only enhance the channel fading resistance and can pro-vide diversity gain and coding gain. Under the MATLAB platform using monte carlo simulation method, the channel capacity and error rate of system are researched. The simulation results show that the MIMO technology can increase the channel capacity;and effectively improve BER performance;the higher the diversity number,the better the commu-nication quality.