An adaptive symbol mapping for BICM-ID

Bit-interleaved coded modulation with iterative decoding (BICM-ID), which possesses low complexity, strong agility, high spectrum efficiency and excellent BER performance, has heen a key technique for next generation of wireless communication. Symbol mapping, defined by the signal constellation and the bit labeling is the crucial design parameter to achieve a high coding gain for BICM-ID. In almost all the existing work, a particular symbol mapping is employed in all the region of SNR. However, there is no a single mapping scheme can always obtain better performance over all the SNRs, because at low SNRs the concentrations of symbol subset affect the performance of BICM-ID more while diversity influence more at high SNRs. CE-8PSK mapping is an outstanding symbol mapping for BICM-ID, with defect-zone existence as well. To achieve an improved performance, CE-8PSK is replaced by Gray or Mixed mapping in defect-zone. Simulation results show that by using the proposed adaptive scheme, a better performance gains up to 1 dB can be achieved for the blind-zone.