Optical spatial modulation with polarization shift keying over atmospheric turbulence channels

We present a novel multiple-input multiple-output (MIMO) optical modulation method that combines spatial modulation (SM) with multilevel polarization shift keying (MPOLSK). The proposed approach, denoted SM-MPOLSK, offers better power and spectral efficiencies than conventional optical modulation methods. We evaluate the performance of SM-MPOLSK over free space optical (FSO) channels and provide average bit error probability (ABEP) bounds for both uncoded and coded performances. The theoretical derivations are also corroborated via extensive simulation results and comparisons with conventional MIMO-FSO modulation approaches.