Irregular Mapping Design for Bit-Interleaved Coded Modulation with Low Complexity Iterative Decoding

Bit-interleaved coded modulation with iterative decoding (BICM-ID) is an effective technology to approach the channel capacity for high-order modulations, which makes it especially fit for the circumstances where both efficient code rate and superior performance are needed, such as bandwidth limited wireless broadcasting or mobile communications. However, to achieve the target of near capacity decoding, many times of iteration is assumed, which heavily adds complexity to the receiving side. If the times of iteration lowers down, considerable degradation could be observed. The design rules of near capacity decoding cannot generally guarantee a still acceptable performance for a few times of iteration. In this paper, to lessen the decoding complexity, an irregular mapping design aiming at maximizing the extrinsic mutual information after a fixed times of iteration is studied. And the simulations show that our method obtains coding gains from 0.4 dB to 1.2 dB at BER=10(-5) compared to other known mappings on condition of 4 times of iteration.