Iterative decoding algorithm with channel adaptation for LDPC codes
Guojun Han, Xingcheng Liu · Journal of Circuits and Systems · 2010
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 to 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.