一种新的WIMAX标准LDPC码的软判决译码算法

WIMAX标准下的LDPC码采用准循环编码方式,其译码多为和积(SP)译码算法。为了进一步降低译码复杂度,通过大量仿真分析获得最优乘性因子的值,并推导出近似线性公式,提出了一种改进型的归一化最小和(MNMS)算法。在此基础上,与校验节点匹配(CNM)算法相结合,进一步提高译码性能。仿真结果表明,这种新算法相比归一化最小和(NMS)算法、抵消最小和(OMS)算法、校验节点匹配(CNM)算法,其译码性能有明显改善,性能几乎接近和积(SP)译码算法。

A novel soft decision decoding algorithm for WIMAX standard LDPC codes

WIMAX standard LDPC is based on quasi-cyclic encoding, and the decoding usually uses the sum-product decoding algorithm. In order to further reduce decoding complexity, a novel modified normalized min-sum （NMS） algorithm is proposed in this paper. The optimal multiplicative factor is obtained by a lot of simulation samples and analyses, and the approximate linear formula is deduced as well. On the basis of it, combining with the check node degree-matched algorithm, the decoding performance is improved further. Simulation results indicate that the proposed novel algorithm improves the decoding performance greatly compared with the NMS algorithm, the offset min-sum （OMS） algorithm and check node degree-matched （CNM） algorithm, and the BER is very close to the sum-product algorithm.