广义QC-LDPC码构造理论研究

项目名称： 广义QC-LDPC码构造理论研究

项目编号： No.61471294

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 无线电电子学、电信技术

项目作者： 张国华

作者单位： 西安空间无线电技术研究所

项目金额： 80万元

中文摘要： 广义QC-LDPC码比传统QC-LDPC码具有更好的译码性能，是近年来国际信道编码领域的一个最活跃的研究课题。广义QC-LDPC码的校验矩阵由若干个尺寸相同的分块矩阵组成，其中分块矩阵可以是全零矩阵、循环置换矩阵或者循环置换矩阵的叠加。本项目拟对广义QC-LDPC码的构造理论展开深入研究。包括（1）研究围长、最小距离的上下界、围长与最小距离的相互约束关系、围长与分块矩阵尺寸之间的约束关系；研究母矩阵及掩模矩阵的构造方法；（2）以围长为优化目标，研究低复杂度搜索方法和无需搜索的直接构造法；（3）研究基于其他优化目标（例如最小距离、近似环路外在信息度（ACE）、陷阱集（trapping sets）、渐进性能、译码器复杂度）的广义QC-LDPC码的构造方法。拟通过本项目研究，期望在完善广义QC-LDPC码构造理论体系的同时，能够为未来空间和卫星通信系统提供更加高效实用的先进纠错编码方案。

中文关键词： 信道编码；低密度奇偶校验码；准循环；卫星通信

英文摘要： Since generalized QC-LDPC codes can outperform classical QC-LDPC codes, they have recently attracted substantial interest in the coding research community. A generalized quasi-cyclic (QC) low-density parity-check (LDPC) code has a parity-check matrix which is composed of several block sub-matrices with the same size. The sub-matrix in a parity-check matrix for a generalized QC-LDPC code may be a zero matrix, a cyclic permutation matrix (CPM) or the summation of several CPMs. The theory and method for generalized QC-LDPC codes will be explored in this research project. The investigation objects include: (1) the upper/lower bound on girth/minimum distance, the relationship between girth and minimum distance, the relationship between girth and the size of block sub-matrices, and the construction method for mother/masking matrices; (2) aiming at large girth, developing low-complexity computer search methods, and explicit methods without any computer search or processing procedures; (3) aiming at other optimization objects, such as minimum distance, approximated cycle extrinsic message degree (ACE), trapping sets, asymptotic performance and decoder complexity, devising construction methods for generalized QC-LDPC codes. Based on the research results of this project, we are hopeful that the theory and method for generalized QC-LDPC codes can be substantially enriched and improved, and that much more practical and efficient channel coding schemes can be developed for future deep space and satellite communication systems.

英文关键词： channel coding;LDPC code;quasi-cyclic;satellite communication