大气激光通信自适应系统中LDPC的识别

Recognition of LDPC codes in atmospheric laser communication adaptive system

从大气激光通信信道模型出发,结合大气激光通信特殊的调制方式,利用接收解调软判决序列的后验概率信息,导出大气激光通信自适应系统中低密度奇偶校验码(LDPC)的识别算法公式。仿真结果表明,当识别正确率为0.8时,在强湍流条件下,算法公式比传统算法性能提高约1.2dB;在弱湍流条件下,算法公式比传统算法性能提高约1.5dB;并且随着码率的降低和码长的增加,识别成功率均有提高。因此,所提算法公式能够进一步抑制大气湍流影响,提高系统性能。

The atmospheric laser communication channel model is established, and the recognition algo- rithrn formula of LDPC codes in atmospheric laser communication channel is proposed by using the received posterior probability information in the soft decision sequence and combining with the atmospheric laser communication special modulation. The simulation results show that when the correct recognition rate is 0. 8, under the condition of strong turbulence, the performance of the proposed algorithm is improved by about 1.2 dB compared with that of traditional algorithm; and under the condition of weak turbulence,the performance of the proposed algorithm is improved by about 1.5 dB compared with that of traditional algorithm. Besides, when the code rate gets lower,and the code length gets larger, the correct recognition rate gets higher.