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为了抑制大气湍流对大气光通信系统性能的影响,将低密度奇偶校验(LDPC)码与多输入多输出技术结合,推导了最大比合并、等增益合并和选择合并三种合并方式下单输入多输出(SIMO)系统译码初始化计算公式,并比较了系统误码性能。仿真结果表明,基于LDPC编码的大气光通信SIMO系统误码性能优于SISO系统;不同的方式下SIMO系统的误码性能不同,信噪比一定时,最大比合并方式的系统误码率最低,等增益合并方式次之;在发射天线数一定时,随着接收天线数增加,系统误码率降低,对大气光通信的系统设计与理论研究具有一定的指导意义。
In order to restrain the influence of atmospheric turbulence on the performance of atmospheric optical communication system, LDPC code combined with MIMO technology is deduced that the maximum input ratio, the equal gain combination and the selection and combination of three kinds of merging mode single input Multi-output (SIMO) system decoding initialization calculation formula, and compared the system error performance. The simulation results show that the error performance of the SIMO system based on LDPC codes is better than that of the SISO system. The BER performance of SIMO system under different modes is different. When the signal to noise ratio is fixed, the maximum BER ratio is the lowest, The equal gain combination is followed by that. When the number of transmitting antennas is constant, as the number of receiving antennas increases, the system bit error rate decreases, which is of guiding significance to the system design and theoretical research of atmospheric optical communication.