On the coverage of multiple-input multiple-output visible light communications [Invited]

Visible light communication (VLC) using multiple-input multiple-output (MIMO) has great potential for future high-data-rate indoor wireless communications. Owing to the dual function of white light-emitting diodes (LEDs), i.e., illumination and communication functions, both the illumination and communication coverages need to be evaluated when implementing an indoor MIMO-VLC system. In this paper, we present a comprehensive investigation of both the illumination and communication coverages of an indoor MIMO-VLC system. Two techniques are applied in the MIMO-VLC system for communication coverage improvement, including a non-Hermitian symmetry orthogonal frequency division multiplexing (NHS-OFDM) modulation scheme and an imaging angle diversity receiver. A general indoor imaging MIMO-VLC system using NHS-OFDM is described and the analytical bit error rate expression of the system is derived. The impact of LED pairing on the communication coverage of an indoor imaging MIMO-VLC system based on NHS-OFDM is also analyzed.