Joint Optimization of Asymmetry and Diversity of Bit-Interleaved Space-Time code

The joint optimization scheme that combined asymmetric modulation with modulation diversity in bitinterleaved space-time coded modulation system (BI-STCM) was proposed. The upper pairwise error possibility was analyzed in BI-STCM under Rayleigh fading channels. The method of achieving modulation diversity and the optimal rotated angle of the constellation to achieve the maximum diversity gain were analyzed. The minimum Euclidean distance between symbols with hamming distance one can be increased in asymmetric constellation for several ordinary symbol mapping schemes. So the coding and diversity gain can be obtained and the upper bound of pairwise error possibility is decreased. Theoretical analysis and simulation results show that the proposed scheme can greatly improve the performance of BI-STCM under Rayleigh fading channels.