基于有限域循环子群方法提出了一种结构简单，可以灵活选择码长、码率，并且编译码复杂度低的准循环低密度奇偶校验（QCLDPC）码构造方法。利用此方法构造出适合光通信系统传输的规则QCLDPC(5334,4955)码。仿真结果表明该码型利用和积迭代译码算法在加性高斯白噪声信道中取得了很好的性能，比已广泛应用于光通信中的经典RS(255,239)码具有更好的纠错性能。因此所构造的QCLDPC(5334,4955)码能较好地适用于高速长距离光通信系统。

A construction method of QuasiCyclic LowDensity ParityCheck(QCLDPC) codes based on cyclic subgroups of finite field is proposed. The method owns the advantages such as easier construction, more flexible adjustment on codelength and coderate and lower encoding/decoding complexity. Moreover, a regular QCLDPC(5334,4955) code suitable for optical communication systems is constructed by this construction method. The simulation results show that the code can gain good performance under the condition of additive white Gaussian noise(AWGN) channel with iterative decoding sumproduct algorithm(SPA). The errorcorrection performance of the QCLDPC(5334,4955) code is better than that of the classic RS(255,239) code which is widely used in optical communication system. Therefore, the constructed QCLDPC(5334,4955) code can be better suitable for the longhaul and highspeed optical communication systems.