中文摘要：

提出了一种基于二维网格法的低密度奇偶校验码（LDPC）构造方法。该方法对斜率集进行更加严格的筛选，利用一组特殊的数列作为斜率子集，该数列中不存在任何三项元素公差相等和任何四项元素公差相等或者成两倍的情况，从而排除线段构成三角形和四边形的可能，突破原有围长8的限制，得到围长为10的LDPC码字，显著提升了误码性能。采用该方法得到的码字校验矩阵具有准循环特性，能保证较低的编译码复杂度。Matlab仿真结果表明，该码在瀑布区域具有良好的性能，同时具有较好的错误平层特性。

英文摘要：

A LDPC construction method based on 2D lattice method is proposed in this paper. With the method,a strict selection of slope sets is carried out to avoid the possibility of forming triangle and quadrangle in configuration. As a result,girthten LDPC was accomplished to improve performance significantly instead of girtheight one known as before. Besides,the resulting paritycheck matrix has the feature of quasicyclic permutation,so that encoding and decoding of these codes can be efficiently implemented by using simple shiftregisters. The result of simulation with Matlab shows that the proposed code performs excellent in the waterfall region and has good error floor property.