中文摘要：

针对大气湍流严重影响无线光通信系统性能的问题，研究了基于低密度奇偶校验（LDPC）码和多输人多输出（MIM0）无线光通信系统性能，给出了基于LDPC码的空时编码MIM0（STMIMO）和重复编码MIMO（repMIMO）系统的解码算法，最后在对数正态模型和K分布模型下进行了仿真分析。仿真结果表明repMIMO系统性能优于STMIMO和单输入单输出（SISO）系统，STMIMO在强湍流情况下性能明显优于SISO系统，基于LDPC码的STMIMO和repMIMO能取得10dB以上的编码增益，并且编码增益随着湍流强度的增大而增加，基于LDPC码和repMIM0的无线光通信系统差错性能更加优异，可以有效提高系统抗干扰能力。

英文摘要：

Atmospheric turbulence produces fluctuations in the irradiance of the transmitted optical beam, severely degrading the performance over optical wireless links. Performance of optical wireless communication based on low- density parity-check （LDPC） codes and multiple-input multiple-output （MIMO） is investigated. Decoding algorithm of repetition coded MIM0 （rep MIM0） and space-time coded MIM0 （sT MIMO） based on LDPC codes is investigated, finally it is simulated in the atmospheric turbulence channel. Simulation results show that rep MIMO outperforms ST MIMO, and LDPC codes have excellent error correction capabilities and access to a larger coding gain. Therefore the sheme based on LDPC codes and rep MIMO can mitigate fading effectively.