Simple near-maximum-likelihood low-complexity detection scheme for Alamouti space-time block coded spatial modulation

Space-time block coded spatial modulation (STBC-SM) has been proposed to exploit the advantages of both spatial modulation and space-time block codes. The first objective of this study is to introduce a very simple near-maximum-likelihood (ML) low-complexity detection scheme for N_t × N_r M-ary quadrature amplitude modulation (M-QAM) STBC-SM. Simulation results validate that the proposed simple detection scheme achieves near-ML detection error performance. Furthermore, in comparison to existing schemes, the computational complexity of the proposed detector was demonstrated to be independent of the modulation size, hence exhibiting a very low computational complexity. The second objective of this study is to present an asymptotic bound to quantify the average bit-error rate performance of M-QAM STBC-SM over independent and identically distributed Rayleigh flat fading channels. The analytical frameworks are validated by Monte Carlo simulations.