自由空间光通信中的MIMO极化编码方法

MIMO Polarization-Coding Method in Free Space Optical Communication

针对自由空间光通信链路性能易受大气湍流影响的问题,构造了一种适用于自由空间光通信的多输入多输出(MIMO)极化编码方法。基于通用偏序法、极化编码、调制及MIMO技术联合优化快速构造极化码,并在大气湍流信道下进行仿真分析。实验结果表明,在不同构造方法及编码方案下,MIMO极化编码方法能在保持低复杂度的同时使系统获得更好的性能。在强湍流条件且误码率为10^(-4)时,相比Monte Carlo方法,偏序法的编码增益约为0.2 dB,且离线构造的计算复杂度可忽略不计;强弱湍流条件下,相比单输入单输出(SISO)-polar方式,MIMO(2×2)-polar方式的编码增益约为1.1~1.6 dB,具有明显的分集优势。

Aiming at the problem that the performance of free space optical communication links is easily affected by atmospheric turbulence,a multiple-input multiple-output(MIMO)polarization-coding method suitable for free space optical communication is constructed in this paper.The rapid construction of the polarization code adopts the universal partial sequence method,polarization-coding,modulation,and MIMO technologies are jointly optimized;the simulation analysis is performed under the atmospheric turbulence channel.The experimental results show that MIMO polarization-coding methods can improve system performance while maintaining low complexity under different construction methods and coding schemes.Under strong turbulence conditions and a bit error rate of 10^(-4),compared to the Monte Carlo method,the coding gain of the partial sequence method is about 0.2 dB.The computational complexity of offline construction is negligible.However,under strong and weak turbulence conditions,compared with the single-input single-output(SISO)-polar method,the coding gain of the MIMO(2×2)-polar method is about 1.1-1.6 dB,which has obvious diversity advantages.