中文摘要：

中短长度LDPC码在采用BP算法译码时,由于短环的存在会导致某些比特LLR值出现振荡现象,从而影响了译码性能。针对这一现象,提出了一种采用消息加权均值来修正校验节点到变量节点消息传递的改进译码算法。该译码算法将上次校验节点到变量节点的消息和本次计算所得的校验节点到变量节点的消息进行加权求和后作为当前最新的消息。通过对本次计算所得的校验节点到变量节点的消息赋予比上次校验节点到变量节点消息更高的权值,从而减弱消息加权均值对正常BP消息传递的影响,有效抑制比特LLR值的振荡。仿真结果表明,与传统的串行迭代译码算法相比,改进的译码算法在计算复杂度增加极少的情况下,有效提高了中高信噪比区的译码性能。

英文摘要：

For short and middle length LDPC codes,the oscillation of LLR owing to cycles degrades the performance of BP algorithm.In order to minimize the oscillation of LLR during BP decoding process,an improved BP algorithm with serial update scheduling using weighted average message to update the message of check-to-variable node is proposed.Currently computed message of check-to-variable node and the message of old check-to-variable node are weighted and then added up to update the message of check-to-variable node.By higher weighted currently computed message of check-to-variable node than the message of old check-to-variable node,the improved algorithm effectively minimizes oscillation of LLR,at the same time,keeps normal BP message propagation and low compute complexity.Simulation results show that,for short and middle length LDPC codes,the improved algorithm achieves more noticeable error performance than CSBP algorithm at middle to high signal to noise ratio.