Construction of Irregular LDPC Codes with Low Error Floors

This work describes a new systematic construction approach for irregular low-density parity-check codes based on the splitting-and-filling technique. The generated code using this proposed method not only has a given degree distribution pair but also has girth of at least six. More importantly, by carefully filling the elements of the variable (check) node sets during the generating process, we can optimize one of the special combinatorial characteristics, such as the stopping size or the girth, of an LDPC code. Simulation results show that the resulting code can achieve good near capacity performance as well as good error-floor performance when decoded using the iterative belief propagation (BP) decoding method.