Differential Orthogonal Space-time Coding Scheme using Multi-amplitude Modulation

摘要

By introducing star-quadrature amplitude modulation (star-QAM) method, a multiple amplitudes differential orthogonal space-time coding scheme is proposed in this paper. The proposed scheme can avoid the performance loss of conventional differential space-time coding (DSTC) schemes based on phase-shift keying (PSK) modulation in high spectrum efficiency via multi-amplitude modulation. Compared with conventional PSK based DSTC schemes, the developed scheme has higher spectrum efficiency via carrying information not only on phases but also on amplitudes, and has higher coding gain. Moreover, the scheme has simpler decoder, and higher code rate in the case of more than two antennas. The simulation results also show that our scheme has lower BER when compared with existing differential unitary space-time coding and differential orthogonal space-time coding schemes.