基于大衍数列的原模图QC-LDPC码一种新颖的扩展方法

A Novel Extension Method of Protograph QC-LDPC Codes Based on dayan Sequences

鉴于大衍数列构造的校验矩阵不存在短环和原模图具有高速译码、低译码平台、低译码门限的优点,将大衍数列与原模图相结合,提出了一种基于大衍数列的原模图QC-LDPC(quasi-cyclic low-density parity-check)码新颖扩展方法。该扩展方法是利用数学规则和大衍数列固定项差对应的值单调递增的特点替换原模图中的元素。该方法构造出的校验矩阵不存在4环,并且用该方法所构造的YD-QC-LDPC码具有优越的纠错性能。仿真结果表明,利用该方法构造的码率为0.5的YD-QC-LDPC(3000,1500)码,在误码率为10-6时,比同码率的基于等差数列构造的APS-QC-LDPC(3132,1566)码提高了1.1d B,并与基于大衍数列构造的DY-QC-LDPC(3000,1500)码相比,其净编码增益(NCG)有显著的提高。

Seeing that the parity matrix constructed by using dayan sequences exists no short cycles and the Protograph has the advantages such as the high speed decoding, the low error floor performance and the low decoding threshold, the dayan sequence is combined with the Protograph, a novel extension method of Protograph Quasi-Cyclic Low-Density Parity-Check（QC-LDPC） codes based on dayan sequence is proposed. The extension method is to replace the elements in Protograph by using the mathematical rule and the character that is the monotone increase of corresponding value of dayan sequences＇ fixed differential. There exists no girth-4 in parity matrix by using this proposed method and the error-correction performance of the Protograph YD-QC-LDPC code constructed by the proposed method is more excellent. The simulation results show that at the bit error rate （BER） of 10^-6, the net coding gain（NCG） of the Protograph YD-QC-LDPC（3000,1500） code based on dayan sequences is 1. ldB more than that of APS-QC- LDPC （3132,1566） code constructed by the construction method based on arithmetic progression sequences, and compared with DY-QC-LDPC （3000,1500） code constructed by the construction method based on dayan sequences, the net coding gain（NCG） of YD-QC-LDPC （3000, 1500） code has a significant improvement. Furthermore, all the codes have the same code rate of 50%.