Multi-Round Belief Propagation Decoding with Impulsive Perturbation for Short LDPC Codes

The belief propagation (BP) decoding of short low-density parity check codes suffers from short cycles and trapping sets. A number of perturbation schemes have been proposed to overcome the limitation. This letter presents a generalized framework for multi-round BP decoding with input perturbation and proposes an improved perturbation scheme. In particular, the impulsive perturbation which is applied to only a few symbols is proposed, along with a new space selection criterion. The proposed scheme performs better than existing schemes for short codes at lower complexity and supports a parallel implementation.