Improved adaptive belief propagation decoding using edge-local complementation

Abstract—This work is an extension of our previous work on an iterative soft-decision decoder for high-density paritycheck codes, using a graph-local operation known as edgelocal complementation (ELC). Inferred least reliable codeword positions are targeted by an ELC stage in between sum-product algorithm iterations. A gain is shown over related iterative decoding algorithms–mainly due to an improved heuristic to determine optimum ELC edges in the Tanner graph–both in error-rate performance, as well as complexity in terms of a significant reduction in the required number of ELC operations. We also present a novel damping operation, generalized to the graph-local setting where extrinsic information remains on edges not affected by ELC. I