中文摘要：

基于循环差族构造了两类多元低密度奇偶校验码,并提出了不同有限域上各个码率的多元低密度奇偶校验码的构造方法.所构造的多元低密度奇偶校验环码（校验矩阵的列重均为2）的围长为12,同时证明了该类码的最小距离至少为6.仿真结果表明,所构造的多元低密度奇偶校验码与用其他方法构造的二元及多元低密度奇偶校验码相比,在加性高斯白噪声信道上二进制相移键控调制下均有性能提升,并且迭代译码收敛速度非常快.

英文摘要：

This paper presents two classes of nonbinary LDPC codes based on cyclic difference families. A method of constructing nonbinary LDPC codes with various rates and over different fields is also proposed. A class of codes whose parity-check matrices consist o：f weight-2 columns, known as cycle codes, has girth 12, and it is also proved that these codes have a minimum distance of at least 6. Simulation results show that the constructed nonbinary LDPC codes outperform the binary and nonbinary codes derived from other constructions over the AWGN channel with BPSK modulation.