I. Introduction
In today's era of ubiquitous communication, optical wireless communication (OWC) employs the vast and unlicensed infrared and visible light spectrum to provide relief to the congested radio frequency (RF) spectrum without affecting the emitted light quality [1], [2]. As in RF communications, parallel transmission can be achieved in OWC using multiple-input multiple-output (MIMO) techniques. In visible light communication (VLC), the multiple light emitting diodes (LEDs) which are required to provide sufficient illumination within a space are potential transmitters that can enable optical MIMO. In this regard, several low bandwidth channels with high signal-to-noise ratio can be combined in optical MIMO to achieve high speed and spectral efficient VLC [3].