硬判决LDPC译码算法在卫星导航中的应用

摘要

低密度校验码（LDPC）在信道条件较差的卫星导航中有着广阔的应用前景,但是地面接收终端采用标准的置信传播算法（BP）或最大后验概率译码（MAP）等软判决译码算法虽然具有较好的性能,但是运算量较大,不利于接收机小型化和降低成本的要求。基于比特翻转（BF）硬判决算法,给出了几种改进型硬判决算法,并在码长较短的条件下比较了它们的译码性能。仿真结果表明：在较短码长的条件下,改进型硬判决译码算法（MWBF）和修正改进型硬判决译码算法（RRMWBF）具有较好的译码性能,能够满足北斗二代短报文通信的要求。%LDPC codes has broad application prospects in satellite navigation and communication under poor channel conditions, but while the ground receiving terminal with BP or MP and other soft-decision decoding algorithm has good performance, its large computing amount is not conducive to receiver miniaturization and cost reduction. In this paper, based on bit flipping hard decision decoding algorithm, several improved hard-decision decoding algorithms are proposed, and their decoding performance comparison is provided under a shorter code length. Simulation results show that ： under the short code length conditions,the improved hard - decision decoding algorithm MWBF and RRMWBF have good decoding performance to meet the short - message communication requirements of Compass Ⅱ.