作　　者： ; ;

机构地区： 中山大学信息科学与技术学院电子与通信工程系

出　　处： 《电路与系统学报》 2010年第1期102-107,101,共7页

摘　　要： 中短长度LDPC码采用BP迭代译码时,在低信噪比区,大量的经过多次迭代仍不能纠正的错误帧造成了平均迭代次数的大大增加;在中高信噪比区,比特对数似然比值的振荡造成了译码性能的降低。为了减少低信噪比区的平均迭代次数,提高中高信噪比区的译码性能,本文提出了一种LDPC码的信道自适应迭代译码算法。该算法采用基于校验和错误模式的预判决机制和消息加权平均算法,通过低信噪比区预判决机制的主导作用来减少平均迭代次数,通过中高信噪比区消息加权平均算法的主导作用来抑制因比特LLR值振荡而形成的错误帧,从而实现译码算法与信道变化特征的自适应,提高了译码效率。仿真结果显示,相对于BP译码算法,该译码算法在低信噪比区减少了平均迭代次数而译码性能没有显著变化,在中高信噪比区提高了译码性能而平均迭代次数没有明显增加。 For short to moderate block-length LDPC codes, a large number of uncorrected error frames causes the increase of average number of iterations in the region of low SNR（Signal-to-Noise Ratio） and the oscillation of some variable nodes degrades the error performance in the region of medium t＇o high SNR. In order to＇reduce the average number of iterations in the region of low SNR and improve error performance in the region of medium to high SNR, an iterative decoding algorithm with channel adaptation is proposed. The decoding method with pre-decision making based on error patterns of check-sum and weighted average message is adopted in this algorithm. Through the primary role of early decision method on reducing average iterations at low SNR and weighted average message on reducing error frames at medium to high SNR, iterative decoding with channel adaptation is realized and high efficient decoding is achieved. Simulation results show that, with the proposed algorithm, the average number of iterations is reduced in the region of low SNR without noticeable error performance degradation, and the error performance is improved in the region of medium to high SNR without obvious increase of the number of iterations compared with standard BP algorithm.

关 键 词： 低密度校验 码 置信传播 错误模式 预判决 振荡

领　　域： [电子电信] [电子电信]