Simple low-complexity detection schemes for M-ary quadrature amplitude modulation spatial modulation

In this study, the authors propose a simple low-complexity detection scheme for N_t×N_rM-ary quadrature amplitude modulation spatial modulation that exhibits a much lower computational complexity compared to the conventional maximum-likelihood (ML) detection scheme. The proposed simple low-complexity detection scheme firstly detects the transmitted symbol for each transmit antenna based on modified suboptimal detection, and secondly chooses N (N≤N_t) pairs of the most probable transmit antenna index and transmitted symbol subset, which the transmitted signal most probably belongs to, and finally searches the pair of transmit antenna index and transmitted symbol among these pairs. To further reduce detection complexity of the proposed simple detection scheme the authors also propose an adaptive detection scheme. Simulation results validate that the average bit-error-rate (BER) performance of the proposed simple detection scheme is almost the same as that of the conventional ML optimal detection with significant complexity reduction. Simulation results also show that the adaptive detection scheme can achieve optimal detection BER performance with further complexity reduction compared to the proposed simple low-complexity detection scheme.