SCM-SM: Superposition Coded Modulation-Aided Spatial Modulation With a Low-Complexity Detector

Spatial modulation (SM) is a spatial multiplexing scheme that utilizes both the signal constellation and antenna index to convey information. In the original SM, traditional modulation schemes such as quadrature amplitude modulation (QAM) are employed for constellation mapping. In this paper, we propose a novel scheme where superposition coded modulation (SCM) is employed to modulate the information onto the constellation points. We also develop a low-complexity iterative detector for our proposed SCM-SM system. Analysis and simulations demonstrate that SCM-SM significantly outperforms the original SM system with the same data rate while maintaining the relatively low complexity, particularly in the high data rate scenario.