3-Bit decoding algorithm for AWGN channels

Simple implementations of decoders for LDPC codes are important practical problems when the decoders have the severe energy consumption constraints or the computation time constraints. A 3-bit decoding algorithm, proposed by Planjery et al. [1], can be regarded as a simplified version of the sum-product algorithm [3]. The algorithm has a very good performance of frame error rate at the error flower region when the algorithm is used for the BSC channels. Although the 3-bit decoding algorithm is not so good for the AWGN channels, it can be shown that the performance of the 3-bit decoding algorithm can be improved by introducing bias terms. It will also be shown that the computation time for the sum-product algorithm can be decreased by applying the 3-bit decoding algorithm to outputs from the sum-product algorithm.