Enhancing LDPC code performance using pilot bits
Jack F. Adolph, Jan Corne Olivier, B.P. Salmon · 2015
Creating the optimal bipartite graph and decoding of aLow Density Parity Check (LDPC) codeword on it is deemedan NP-complete problem. Much work in the last decade hasgone into proper construction of LDPC codes with maximumgirth and optimized stopping sets; to ensure the BERapproaches channel capacity. When an edge alteration to thegraph is proposed, it completely changes the performance ofthe graph and usually leads to the re-analysis of the entiregraphs properties. In this work we propose a method oflowering the error floor experienced in an LDPC code by intelligentlyinserting a set of known bits in the message frame.This deactivates paths in the graph located around trappingsets without modification of edges in the graph, and provideshigh log-likelihood information to the induced sub-graph forimproved performance.