二进制和多进制LDPC编码调制系统的带宽有效传输

摘要

A reliable and bandwidth-efficient data transmission is required in modern communication systems. The performances of bina ry and nonbinary low-density parity check（LDPC） coded modulation systems over the AWGN channel are analyzed and discussed. The model of nonbinary LDPC coded modulation system is established, and the initialization of iterative decoding is discussed. The information transfor marion method is presented when the LDPC code and high order modulation are unmatched. Simulation results show that nonbinary LDPC coded modulations can achieve a better performance than binary LDPC coded modulations over an AWGN channel. Nonbinary LDPC high order QAM with Gray labeling achieves a better performance compared to other combinations.%针对现代通信系统对数据传输可靠性和频谱有效性的需求，文章分析和讨论了二进制和多进制低密度奇偶校验（Low Density Parity-Check，LDPC）编码调制系统在AWGN信道下的性能。建立了LDPC编码调制系统模型，分析了迭代译码的初始化条件，给出了当LDPC码进制数与高阶调制阶数不匹配时软信息的转换方法。仿真结果表明，在AWGN信道下，多进制LDPC编码调制系统具有很好的误码特性，采用16QAM格雷映射方式相比于其它组合方式可以取得更好的误码性能。