基于振荡迭代的修正BP译码算法

针对中高信噪比(SNR)下低密度奇偶校验(LDPC)译码错误振荡迭代不收敛,提出了基于置信传播(BP)算法的修正LDPC译码算法,即软值归零BP算法。该算法通过将振荡迭代的变量节点传递的外信息置零,减少错误信道消息对迭代译码的影响,较大地改善了译码性能。而且,还给出了振荡迭代节点的判定准则,提高了振荡迭代节点判定的准确性。仿真结果表明,在中高信噪比区且译码迭代次数相同的情况下,该算法能比BP算法获得更好的译码性能。

A Modified belief propagation decoding algorithm for low-density parity-check codes based on oscillating iteration

According to no-convergence of falsely oscillating iteration in the low-density parity-check(LDPC) decoding at the range from medium to high SNRs(Signal to Noise Ratios),we propose a modified LDPC belief propagation(BP) decoding algorithm,i.e.soft value zero-forcing BP algorithm.By setting extrinsic information of the oscillating iteration bit nodes into zero,the impact on the iteratively decoding from false channel information is greatly reduced.And it also improves the performance of the decoding algorithm.Furthermore,a decision criterion of oscillating iteration nodes is presented to increase the accuracy of the decision.Simulation results show that the proposed algorithm has better decoding performance than that of the BP algorithm with the same iterations at medium and high SNRs.