Structure protection for improving performance of low-density parity-check codes

As Tanner graphs (TG) of LDPC codes and channel noise distributions have some relationship, codes have considerable variation in performance even if they have a given code, given iterative decoding algorithm and given channel model. We present a new structure protection algorithm based on what we define as the noise sensitive nodes of TG. The structure protection algorithm can reduce the probability of bad noise distribution patterns which results in the degradation of decoding performance. Simulation results show that structure protection algorithm outperforms the conventional LDPC codes in both error performance and decoding speed.