An Accurate HARQ Scheme for LDPC

An accurate hybrid ARQ (HARQ) scheme for irregular LDPC codes is introduced in this paper, in which the source retransmits the nodes at specific proportions each time. The proportions of retransmission bits can be specified in definite quantity with Gaussian Approximation (GA) and optimal method as long as degree distribution and initial channel state are known. It provides an accurate mean to evaluate other HARQ schemes for LDPC coded system. The traditional Degree Distribution Based HARQ (DDB-HARQ) is also studied and compared with the proposed one. Statistic and numerical results are presented and we can conclude that the new scheme has optimal performance in the HARQ schemes based on degree distribution of LDPC codes.