Intensive Testing of Infrastructure-to-Vehicle Visible Light Communications in Real Outdoor Scenario: Evaluation of a 50 meters link in Direct Sun Exposure

Due to numerous advantages, Visible Light Communications are considered to have high potential in providing support for communication-based vehicle safety applications. In this area, Infrastructure-to-Vehicle communications are one of the main use cases. Nevertheless, the outdoor communication channel is very problematic affecting the reliability of VLC systems. In this paper we perform an intensive day test for such a VLC link. The purpose is to experimentally determine the influence of the sun power and of sun orientation on VLC, emphasizing and analyzing the effect of the sunlight on the link performances. Another aim of this experimental investigation is to identify potential vulnerabilities in order to provide support for future developments. For this set-up we used a standard complying LED traffic light as a VLC emitter and an enhanced design of photodiode-based VLC receiver using a novel logarithmic transimpedance configuration. The experimental results showed that the sun can have a major influence on outdoor VLC. Nevertheless, they also showed that with a proper system design and with adequate signal conditioning, VLC can support 50 meters communication ranges in automotive applications.