Ubiquitous 3D positioning systems by led-based visible light communications

Abstract

Currently, LEDs are popularly employed in our daily life due to various advantages. LEDs can also be employed for wireless data communications (i.e., VLC). Based on these LED-VLC systems, we can obtain high-performance positioning systems beyond the performance of RF communications or global positioning systems. In this article, we present a brief overview of positioning approaches in VLC systems, and also propose a maximum likelihood approach for the positioning system. Currently, the main technologies employ triangulations or image sensors for positioning a receiver in VLC systems. The least squares method is popularly employed for triangulation approaches in various ways, and we enhance the positioning performance by employing an iterative maximum likelihood approach by adopting the least square solution as an initial guess. We show the optimality of the proposed approach based on sufficient SNR.