Spatial Correlation Analysis of MIMO Channel in Indoor Visible Light Communication

This paper addresses the spatial correlation of MIMO channel with application to indoor Visible Light Communication (VLC). This study establishes a model for indoor VLC MIMO channel based on the Lambert radiation model, and then analyzes the effect on the spatial correlation of both transmit and receive channel by different distance parameters in this model. Thus, the mathematical expressions of the spatial correlation coefficients of both transmit and receive channel are derived, which can provide a theoretical guide to the layout of the indoor VLC MIMO system. The simulation results regarding the channel matrix condition verify that the channel spatial correlation becomes stronger with the decreasing of Light Emitting Diode (LED) spacing, PhotoDetector (PD) spacing, and the increasing of the vertical distance from LED to PD. In addition, the channel capacity simulation results show that the channel capacity can be enhanced by increasing the number of LED and PD, whereas the channel capacity gain can be reduced with stronger channel spatial correlation.