Maximizing Constrained Capacity of Power-Imbalanced Optical Wireless MIMO Communications Using Spatial Modulation

In this paper, we present a constellation optimization technique that can be invoked for optical spatial modulation (OSM) multiple-input multiple-output (MIMO) systems within the context of optical wireless (OW) systems that is designed to negate the high channel correlation imposed on conventional OSM schemes. More specifically, the proposed unified OSM architecture relies on power-imbalanced (PI) multiple transmit light sources. Furthermore, we formulate the constrained capacity of the proposed PI-OSM scheme, and then provide the design guidelines of our OSM scheme´s PI constellation, in which the parameters have been optimized to ensure the associated constrained capacity is maximized. Our simulation results demonstrate that our proposed scheme is capable of outperforming conventional OSM and OW-MIMO schemes over a wide range of signal-to-noise ratios.