Four-Dimensional Hybrid Signals with Spatial Modulation Systems

We consider the way to constructing spatial modulation (SM) scheme, which uses the combination of binary frequency-shift keying and M-ary phase shift-keying signals. In order to better evaluate the antenna index, for each active antenna, we use different types of constellations of the same size obtained from the known system of signals. On the receiving side, we use the maximum-likelihood (ML) detection, according to which the values of the index of the active antenna and the index of the signal transmitted from it are simultaneously estimated. Examples of SM system are shown, and computer simulation results are given over Nakagami-m (Rayleigh) flat-fading channels. The presented results, for spectral efficiency 3–6, indicate the improved characteristics compared to the known systems with the same parameters.