具有大码间距和大环路的QC-LDPC码的构造

Construction of QC-LDPC codes with large minimum distances and large girths

本文总结了基于循环移位矩阵的QC-LDPC码的基矩阵和校验阵在维度、最小码间距和环路特性方面的关系。在此基础之上,本文提出了同时具有大的码间距和好的环路性能的QC-LDPC码的构造方法,首先构造了具有优化的维度分布和较大的最小码间距的基矩阵,再为基矩阵对应的模矩阵选择合适的循环偏移参数,从而构造了一类同时具有大码间距和大环路性能的QC-LDPC码。仿真结果表明,本文构造的QC-LDPC码,在相当宽的码长范围内优于802.16e标准的QC-LDPC码。

The properties of the degree distribution,minimum distances and girths of QC-LDPC codes based on permutation matrixes are represented in this paper.A set of QC-LDPC codes simultaneously possessing large minimum distances and large girths is proposed.The construction of a QC-LDPC code can be divided into two steps,constructing a base matrix with suitable degrees and a large minimum distance and choosing proper shifting sizes for its model matrix.Simulation results show that the proposed methodology can outperform the LDPC code adopted by 802.16e within a wide range of code lengths.