基于Hoey序列的QC-LDPC码构造方法

摘要

基于Hoey序列提出了一种列重为3,并环长至少为8的准循环低密度奇偶校验(quasi-cyclic low-density parity-check,QC-LDPC)码的新颖构造方法,该构造方法能避免短环的产生,有较好的纠错性能,可通过改变参数值进而改变码长和码率.对提出的构造方法进行了环长至少为8的证明,用Matlab搭建了通信系统的仿真模型,并在此模型基础上对基于该构造方法构造的QC-LDPC(900,452)码进行了仿真分析,仿真平台是在高斯白噪声(additive white Gaussian noise,AWGN)信道下,调制方式为二进制相移键控(binary phase shift keying,BPSK)调制,译码算法为和积算法(sum product algorithm,SPA).仿真结果表明,当误码率(bit error rate,BER)相同时,利用该构造方法所构造的QC-LDPC(900,452)码的净编码增益(net coding gain,NCG)比基于等差数列(arithmetic progression sequence,APS)构造的QC-LDPC(896,452)码以及基于最大公约数(greatest common divisor,GCD)构造的QC-LDPC(900,453)码的NCG都提高了,且所有码的码率均为0.5.%A novel construction method of quasi-cyclic low-density parity-check(QC-LDPC) codes with girth of at least eight and the column weight of the constructed QC-LDPC code is 3 based on Hoey sequence is proposed.The novel construction method can avoid short-girth and has better error-correction performance.Moreover,the code length and the code rate can be adjusted by selecting different parameters.Firstly,the girth of at least eight in the proposed novel construction method is proved,and then the simulation model of communication system is established by Matlab program.And based on the model,the QC-LDPC (900,452) code constructed by the proposed construction method is emulated and analyzed.The simulation environments are addictive white Gaussian noise(AWGN) channel,binary phase shift keying(BPSK) modulation method and the decoding algorithm of the sum product algorithm(SPA).The simulation results show when the bit error rate (BER) is the same,the net coding gain(NCG) of the QC-LDPC(900,452) code is more than those of the QC-LDPC (896,452) code constructed by the construction method based on the arithmetic progression sequence(APS) and the QCLDPC(900,453) code constructed by the construction method based on the greatest common divisor(GCD).Furthermore,all the codes have the same code rate of 50％.