提出了一种低复杂度的具有等差数列(AP)特性的准循环低密度奇偶校验(QCLDPC)码构造方法,该方法结构简单,节省了存储空间,可根据实际需要灵活地改变码长和码率。利用该方法构造出的AP-QC-LDPC(4599,4307)码的校验矩阵的每行元素为等差数列,且公差单调递增,所以该校验矩阵不含有4环。仿真结果表明:在误码率(BER)为10-6时,该AP-QC-LDPC(4599,4307)码比ITU-T G.975中的RS(255,239)码和ITU-T G.975.1中LDPC(32640,30592)码的净编码增益(NCG)分别改善了约2.19和1.48dB,比基于有限域乘群的eIRA-QC-LDPC(4599,4307)码和QC-LDPC(3780,3540)码的净编码增益分别提高了约0.16和0.2dB。该方法构造的AP-QC-LDPC(4599,4307)码具有更好的纠错性能,能更好地适应光通信系统的需求。 A low-complexity quasi-cyclic low-density parity-check (QCLDPC) code construction method with equal-difference sequence (AP) characteristics is proposed. The method has the advantages of simple structure, saving storage space and flexible code length change according to actual needs And bit rate. The parity check matrix of the AP-QC-LDPC (4599,4307) code constructed by this method has an equal-difference sequence and the tolerance increases monotonically. Therefore, the check matrix does not contain any four rings. The simulation results show that the AP-QC-LDPC (4599,4307) codes are better than RS (255,239) codes in ITU-T G.975 and ITU-T G.975.1 The net coding gain (NCG) of the LDPC (32640, 30592) codes is improved by about 2.19 and 1.48 dB, respectively, compared with the eIRA-QC-LDPC codes and the QC-LDPC codes (3780 and 3540) ) Code has a net coding gain of about 0.16 and 0.2 dB, respectively. The AP-QC-LDPC (4599, 4307) code constructed by this method has better error correction performance and can better meet the requirements of optical communication system.