EXIT-Chart Based Labeling Design for Bit-interleaved Coded Modulation with Iterative Decoding

In this paper, labeling is jointly designed with the outer code by the EXIT chart based analysis to improve the performance of bit-interleaved coded modulation with iterative decoding. A systematic design methodology is proposed for regular modulation schemes which can easily obtain a set of labelings with various slopes. Given an outer code, the optimal labeling which has the steepest slope but still makes the tunnel between the decoder and demapper transfer curves open can then be chosen to optimize the BER performance. Verified by the simulation results, our design can provide remarkable SNR gain over the conventional ones.