【摘要】 文章将阐述一种结构化的LDPC码系列,包括规则码、非规则码、非规则RA码三种。这种结构把H矩阵分为3×k个块,而每个块都是由单位矩阵循环移位形成的。非规则就是在规则码结构上添加3×m个块,使得H矩阵前面部分列重从3变为6或者9,非规则RA码在非规则基础上将H阵最后部分(3×3块)换成2列下三角结构。生成这类H矩阵的方法就是以下要提到的代数搜索法。搜索法规则就是尽量将低次环去掉,保持H阵的高girth值。这个系列的LDPC码的好处就是译码器结构很好实现,RA码使编码也变得很简单;而完全去除4,6环,最小化8环的H阵结构又保证了LDPC码的性能。更多还原

【Abstract】 This paper will present a series of structural LDPC code,including regular code,irregular code and irregular-repeat-accumulation code.The referred structure divide the H matrix into 3*k blocks,the identity matrix shift all its‘1’s(quasi-cyclic) to construct each blocks.Irregular code is based on regular one,adding 3*m blocks,then the column weight from 3 goes to 6 or 9 at the front of H matrix.Irregular-repeat-accumulation code is based on irregular one,replaces the bottom of H matrix(3*3blocks) with a 2 line down triangular matrices.Generating the three types of H matrix will use the corresponding searching-method mentioned blow.The main rule of the searching-method is to eliminate lower circles in H matrix,keep the average girth of the H matrix high.The advantage of this series of structural LDPC code is that the decoder hardware structure can be comparatively easy implemented.Encode of repeat-accumulation code become easy,too.In fact,because of the elimination of 4th,6th circle,minimization 8th circle in H matrix,the performance of this series LDPC code quite good as well.更多还原