联合度分布优化下扩展双对角线LDPC码构造

Construction of LDPC Codes with Enlarged Dual Diagonal Structure under Joint Optimization for Degree Distribution

具有低编码复杂度和低存储量的LDPC码构造算法一直是纠错编码领域的研究热点。本文根据现有对e IRA码和QC-LDPC码的研究,提出一类具有扩展双对角线的LDPC码构造算法。该码以e IRA码作为QC-LDPC码的基码,同时具有两者低编码复杂度和低存储量的特性。为了减少该结构下基矩阵扩展后引入的多个度为1的节点对码性能造成影响,本文结合该码的结构特点提出一种基于EXIT图的联合度分布全局优化算法,有效提高了码的性能。实验结果表明,相较于IEEE802.16e与IEEE802.11n标准中相同条件下的标准码,本文所构造的QC-LDPC码的性能可提高约0.1d B。

The construction of low-density parity check codes with low encoding complexity and storage is a hot issue in the study of error correction coding.According to the existed research of QC-LDPC codes and eIRA codes,we propose a construction method for a kind of LDPC codes with enlarged dual diagonal structure,which fix eIRA codes as their base codes and take the advantages of low encoding complexity and storage.In order to eliminate the influence caused by the im-port of degree-1 variable nodes during the extension of base matrix,we propose a joint degree optimization algorithm based on EXIT chart analysis.It improves the code performance significantly.Simulation results show that the code constructed in our method outperforms that in IEEE802.16e and IEEE802.11n standard about 0.1dB under same condition.