改进的低复杂度BP译码算法  

An Algorithm of the Improved Low-complexity BP Decoding

作　　者：雷洪利[1] 孙康宁[2] 马林华[2] 张嵩[2] 胡星[2] 关瑛 

机构地区：[1]西北工业大学 [2]空军工程大学航空航天工程学院 [3]94188部队通信修理所

出　　处：《空军工程大学学报（自然科学版）》2016年第2期53-57,共5页Journal of Air Force Engineering University(Natural Science Edition)

基　　金：综合业务网及关键技术国家重点实验室开放研究课题(INS-15-13)

摘　　要：基于对数似然比的BP译码算法与标准BP译码算法相比,降低了一定的运算量,但仍具有较高的计算复杂度,硬件实现时需要消耗较高的资源。针对此问题,提出了一种变量节点动态更新选择的对数似然比BP译码算法,根据每一次迭代后变量节点外信息的收敛情况及校验方程的满足情况,动态地选择置信度最低的部分节点参与更新,其他置信度较高的节点则不进行更新。仿真结果显示,该算法译码性能与对数似然比BP译码算法相比,在0.5码率,10-4误码率时,1 024码长有0.1dB的性能损失,2 048码长性能损失仅有0.07dB,但从第4次迭代开始归一化运算量至少降低了50%。Compared with the standard BP decoding, the BP decoding based on LLR reduces the computation burden, but is still complex. As a result, this may consume lots of hardware resources. To solve this problem, this article proposes an improved LLR-BP decoding algorithm with dynamic bit node selection. According to the recursion of extrinsic messages and the satisfaction of parity equation, the part of nodes whose belief is the lowest is selected dynamically to participate in next iteration and update their extrinsic message. At the same time, the other variable nodes don＇t need to update their extrinsic messages in next iteration. The simulation result shows that the loss of the performance of advanced algorithm in signal-to- noise is 0.1 dB and 0.07 dB compared with standard LLR-BP decoding algorithm, when the code-length is 1 024 and 2 048 at 10-4 bit-error rate and at 0.5 code rate.

关 键 词：BP译码 低密度奇偶校验码 复杂度 外信息 可靠度 

分 类 号：TN911.22[电子电信—通信与信息系统]