Asymptotic performance analysis of LDPC codes with channel estimation error

In this paper we investigate the asymptotic behavior of belief propagation algorithm for low density parity check (LDPC) codes over additive white Gaussian noise (AWGN) channel when there is an incorrect estimate of the channel noise power. We propose a computationally efficient method to compute the convergence threshold values for both regular and irregular codes and show that these values are consistent with simulation results for the codes with finite block lengths. The effect of imperfect channel estimation on EXIT charts of variable nodes and check nodes is also investigated.