An Improved Check Polytope Projection Penalized Algorithm for ADMM Decoding of LDPC Codes

The Euclidean projection onto check polytope is the most complicated and time-consuming operation in the alternating direction method of multipliers (ADMM) decoding for Low-Density Parity-Check (LDPC) codes. The check polytope projection penalized algorithm can avoid the tedious work of penalty parameter optimization and simplified the calculation process of check polytope projection. However, the over-punishment of check polytope projection penalized algorithm may lead to poor decoding performance, when combined with the over-relaxation technique. In this paper, an improved check polytope projection penalized algorithm is proposed. In order to reduce the ratio of even-vertex projection, we restrict the points far away from the even-vertex of the check polytope by introducing the penalty constraint condition. Simulation results show that the frame error rate (FER) performance of the proposed algorithm is almost the same as that of the cut search projection algorithm (CSA), and it can save the average decoding time by 22.9%–52%.