Uniformity optimization for indoor visible light communications with multiple light sources

Abstract

Indoor wireless communications scenario is one of the most typical applications for visible light communications (VLC). To make the best of indoor VLC, the overall system performance relies heavily on the illumination and received power uniformity of the receiving plane. To achieve this goal, we first propose a general symmetric double-rectangle (SDR) layout scheme suitable for rectangular indoor spaces, while its symmetry reduces the dimension of the subsequent optimization and improves the illumination and received power uniformity. We apply the SDR scheme into two models according to different layout method at the center of the spaces, named SDR-3P and SDR-2P, respectively, in a (5 × 5 × 3)m 3 rectangular cube. Simulation results show that, compared with the traditional four-light model, the uniform illumination ratios (UIR) of the two models, SDR-3P and SDR-2P, are improved by 14.3% and 28.6%, respectively, while the power standard deviations are reduced by 17.9% and 53.6%. To further improve the received power uniformity, we use an adaptive differential evolution algorithm, named JADE to optimize the position of light sources. Based on the above optimizations, we further consider the influences of transmit power and refractive index on the receiving plane, which also affect the received power and illumination uniformity. The final results show that, compared with the traditional four-light model, both the illumination and the received power uniformity are greatly improved, with the UIR improved by 47.6% and 33.3%, and the power standard deviation reduced by 84.0% and 73.2%, respectively.