An adaptive incremental redundancy scheme for LDPC code based on the mutual information model

The spectrum efficiency will be improved obviously, if the least number of retransmitted check bits of traditional Incremental Redundancy (IR) scheme is adaptively changing to meet the target error probability according to the instantaneous channel state. Based on the mutual information (MI) model, as well as the new Rate Compatible (RC) LDPC code family whose check nodes can be changed one by one, the proposed Adaptive IR (AIR) scheme meets exactly the reliability requirement of a certain RC-LDPC coded system in a wide range of channel state, occupying the least radio resources. Thus the AIR scheme maximizes the throughput of the system.