On Suboptimum Component Decoding for Product Codes

The performance and convergence behavior of the iterative schemes for decoding two-dimensional product codes are investigated. The decoding trajectories of the extrinsic and the a posteriori information are used as a main tool for predicting and explaining the behavior of the iterative decoding process. The component-wise optimal BCJR decoder is compared to the suboptimal max-log-MAP decoder and the list-based BEAST-APP decoder in terms of convergence and bit-error-rate performance. The results are illustrated by examples, which show that the BEAST-APP decoder achieves near-BCJR performance with significantly lower complexity.