Institute of Electrical & Electronic Engineers
This paper addresses the prediction of error floors of variable-regular Low Density Parity Check (LDPC) codes in the Additive White Gaussian Noise (AWGN) channel. Specifically, the authors focus on the Sum-Product Algorithm (SPA) decoder in the log-domain at high SNRs. They hypothesize that several published error floor levels are due to numerical saturation within their decoders when handling high SNRs. They take care to develop a log-domain SPA decoder that does not saturate near-certain messages and find the error rates of their decoder to be lower by at least several orders of magnitude. They study the behavior of near-code-words/trapping sets that dominate the reported error floors.