一种改进的LDPC码译码算法研究

针对传统BP算法运算复杂度较高的问题,将BP算法和WBF算法相结合提出LDPC码改进译码算法。在每次BP迭代译码中加入校验式判断,并利用一定的翻转判据进行加权。然后对满足条件的位进行翻转,再次进行校验式判断,加快获得许用码字的速度。在加性高斯白噪声信道下的仿真结果表明,此改进译码算法能有效降低译码的平均运行时间,并且能够保持和传统BP算法一样的优异译码性能。并针对不同最大迭代次数,不同码长,不同码率情况,对改进译码算法和传统BP算法的性能进行详细比较。

Research on an Improved Decoding Algorithm for Low-Density Parity-Check Codes

To solve the problem of high average running time, an improved decoding algorithm was proposed which was combined by BP algorithm and WBF algorithm. The parity check was added in each BP iterative decoding, and flipping criterions which were passed from check nodes to information nodes were weighted by the reliable information of received sequence. Then a bit flipping measure was to be taken according to specific rules in order to obtain correct codes, and a parity check was added again. Simulation results on Additive White Gaussian Noise (AWGN) channel show that, the improved algorithm can decrease the average running time effectively for LDPC codes while maintaining the excellent decoding performance as BP algorithm. And compared with classical BP algorithm, we analyze the effect of the different maximum numbers of iterations, different lengths of codes and different code rates for the improved decoding algorithm.