Optimization of LDPC Codes by Extrinsic Information Transfer Chart
Jing Xi Zhang · Applied Mechanics and Materials · 2013
The optimization of degree profiles of low-density parity-check (LDPC) code in additive white Gaussian noise (AWGN) multiple access channel (MAC) by fitting the transfer characteristics of variable nodes detector (VND) and that of check nodes detector (CND) is discussed. Extrinsic information transfer (EXIT) characteristics are used for determining the degree profiles based on curve fitting. The convergence the optimized LDPC code is ensured by the EXIT characteristics of VND and CND. Degree profiles are obtained and check matrix is constructed. Simulation results show that the method is variable in designing LDPC code degree profiles in MAC with reduced complexity compared with density evolution based on Gaussian approximation.