准循环LDPC码快速编译码算法及DSP实现

为了降低准循环低密度奇偶校验QC-LDPC(quasi-cyclic low-density parity-check)码编译码算法的复杂度,研究了QC-LDPC码的构造方法.介绍了一种由校验矩阵构造系统生成矩阵的简化方法,该方法可以在很大程度上降低编码复杂度,实现线性编码.基于上述校验矩阵结构,译码提出了Turbo串行消息传递的最小和译码算法(TMS算法).在保持性能基本不变的情况下,改善消息传递的收敛特性,同时降低译码复杂度.基于定点DSP结构,设计了一种高效LDPC码编译码器.仿真结果表明,该算法以较低的复杂度实现了QC-LDPC码的快速编译码.

Efficient encoding-decoding algorithm of QC-LDPC and DSP implementation

T o reduce the complex ity of enco der-deco der, the const ruct ion o f Quasi-Cyclic Low -Density Parity- Check ( QC-LDPC ) codes w as studied. A simplified method to f ind the sy stemat ic g enerator matr ix fr om it s parity check mat rix w as int ro duced w hich co uld great ly reduce the encoding complex ity and r ealize linear encode-able codes. A mo dified T ur bo ser ial messag e passing schedule for min-sum alg orithm was applied with approx imately the same performance as the sum-pr oduct algorithm, w hich updated messag es immediately and converges fast . Based on the fix ed point DSP, a high performance enco der-deco der were desig ned. T he simulat ion result show s that this alg orithm real izes ef f icient enco ding and decoding w ith low complex ity .