Optical Interference Reduction with Spatial Filtering Receiver for Vehicular Visible Light Communication

Abstract

We present a novel receiver-based interference reduction mechanism for Vehicular Visible Light Communication (V-VLC). V-VLC, in combination with Radio Frequency (RF)-communication, is a technology that is promising to enable a reliable communication link for a number of Intelligent Transportation Systems (ITS) applications such as cooperative driving. Both technologies complement each other to overcome technology-dependent limitations. Particularly, V-VLC is drawing attention as it is able to provide rather high capacity links. Nevertheless, it was observed that V-VLC suffers from interference caused by ambient light as well as modulated light sources, for instance LED signage. To overcome this barrier, we propose a system that makes use of the Line of Sight (LOS)-characteristic and imaging optics. More precisely, we are using a spatial light modulator in the form of a Liquid Crystal (LC)-panel to spatially filter interference and ambient light, thereby reducing interference to a minimum. We built and tested a photodiode-based receiver for V-VLC and, validated by simulations and measurements, we demonstrate the capability of the system.