GF(q)域上LDPC码的改进扩展最小和译码算法

Improved Extended Min-sum Decoding Algorithm of LDPC Codes over GF(q)

通过分析扩展最小和算法(EMS)存在的问题,提出了一种针对q元LDPC码的改进译码算法.不同司于EMS算法固定每次迭代中FHT的阶数,该算法根据每次迭代中变量节点的概率分布对的平均方差自适应选择FHT的阶数,并修改发生振荡的变量节点输出信息,使之同时包含上次迭代和当前迭代的信息,从而减少性能的损失与振荡的影响.仿真结果表明,在译码复杂度相当的情况下,该算法性能与收敛速度明显优于EMS算法.

To overcome the drawback of the extended min-sum algorithm （EMS）, an improved EMS decoding algorithm is proposed, which is designed for LDPC over GF（q）. The algorithm adaptively chooses the rank of FHT in each iteration step according to the average variance of bit nodes＇ probability pairs. It differs from the original EMS algorithm in which the rank of FHT for each iteration step is a constant. Moreover, for oscillating variable nodes, the message of the previous iteration is added to the current message in the iterative procedure to reduce loss of performance and effects of oscillation. Experimental results show that the proposed algorithm can achieve better performance and converge faster than EMS with the same decoding complexity.