Optimization of LDPC Codes for Turbo Equalization Based on PSO-EXIT Algorithm

Optimization of LDPC codes based on EXIT chart of MIMO channel is recently proposed by Brink. In this paper,Brink's idea is extended to optimization of LDPC codes for MMSE turbo equalization. First a new method to obtain EXIT curves of the receiver was given. Furthermore a new optimized scheme of LDPC codes for turbo equalization, PSO-EXIT algorithm, was proposed, which combined He's modified Particle Swarm Optimization(PSO) algorithm with EXIT chart method. Decoding trajectory of (3,6)regular LDPC codes for MMSE turbo equalization was also analyzed in this paper. The degree distribution pair of the optimized irregular LDPC codes were compared with the result of Narayanan's. Simulation results shows that the proposed scheme is effective.