Performance Comparison of Different Spatial Modulation Schemes in Correlated Fading Channels

In this paper, we introduce TOSD-SM (Time-Orthogonal Signal Design assisted Spatial Modulation), which is a novel space modulation scheme based on the principle of the recently proposed Spatial Modulation (SM) wireless transmission technique for Multiple-Input-Multiple-Output (MIMO) systems. We show that, unlike other SM-based methods available in the literature, the proposed approach can offer transmit-diversity gains by properly designing the transmitted signal to have a peaky time auto-correlation function. By considering the basic 2-by-1 MISO (Multiple-Input-Single-Output) system setup, the optimal Maximum-Likelihood (ML) detector with full Channel State Information (CSI) at the receiver will be developed, and its performance evaluated in closed-form. Performance comparison with other proposed SM schemes over fading channels will evidence two main benefits of TOSD-SM: i) transmit-diversity gains, and ii) intrinsic robustness to spatial correlation of channel fading. Analytical frameworks and findings will also be substantiated via Monte Carlo simulations.