Anti-Shadowing Design of Visible Light Communication and Positioning Systems with Equivalent Virtual Lamps

Abstract

The transmission of signal with visible light is constructed with a link consisting photo-detectors and lamps, where the transmitted signal is rebuilt via different line-of-sight (LOS) and non-line-of-sight (NLOS) propagation with LOS generally dominant. In visible light communication (VLC) scenarios, there are requirements to ensure the flatness of both illuminance and signal-to-noise ratio (SNR) distribution across the receiving plane. In the case of visible light positioning (VLP), the basic requirement is to keep enough number of lamps to have LOS links achieving the positioning plane. However, the design of both VLC and VLP systems are strictly limited by a sophisticated combination of the parameters of the photo-detector and the lamps. In real applications, it may deviate from the desired working condition. In VLC system, multipath propagation and signal dispersion significantly influence the system performance, while in VLP, LOS link between LEDs and receiver could be obstructed. These problems will result in performance deterioration of a VLC system or even failure of the VLP system. In this paper, we proposed a mirror-assisted scheme to alleviate such problems, based on the assumption of equivalent virtual lamps. By introducing specular reflection, we can obtain increased received power, mitigating the impact of diffuse reflection and make it possible to implement VLP with limited accessibility of LEDs. With the integrated design and characteristics by considering both existing and virtual lamps, the enhancement of the anti-shadowing performance can be expected in both VLC and VLP systems with a flexible approach.