Considering the traditional Gray mapping achieves limited performance at medium-to-high SNR region, in order to optimize the performance at mid-high SNR region for BICM-ID system, a new scheme of constellation mapping of 16QAM was proposed by redistributing bit position. This novel mapping manages to raise the unequal degree of protection. Finally, experiments based on the criterion of mutual information analysis are performed. Through analysis and comparisons with several previous constellation mapping schemes in terms of channel capacity in BICM-ID system, simulation results reveal that the novel mappings outperform the Gray mapping scheme in the aspect of channel capacity which indicates about 2.38bit/channel at medium-to-high SNR region.
