Experimental demonstration of highway I2V using visible light communications.

A visible light communication (VLC)-based intelligent transportation system (ITS) has drawn much interest from telematics and automobile industries due to its enhanced safety and cost effectiveness. Within the framework of ITS, vehicle-to-vehicle and infrastructure-to-vehicle (I2V) communications have largely been considered. I2V can be viewed as an important ITS technology that broadcasts traffic information from fixed traffic infrastructure. In this paper, an experimental demonstration of a highway VLC-based I2V system is presented. For robust and reliable detection in the VLC-based I2V, the receiver structure of the proposed system is comprised of an optical filter, a color filter, and a Fresnel lens. We consider two primary atmospheric conditions in the highway I2V, i.e., sunlight and cloud effects. To alleviate these adverse effects, we propose an efficient and robust zone detection (ZD) and adaptive decision threshold (ADT) method. The sunlight effect is reduced predominantly by the ZD, while the cloud effect is lessened significantly by the ADT. The experimental results demonstrate that the proposed method performs well to counter the sunlight and cloud effects. It is found that the proposed ZD and ADT method provides an approximate SNR improvement ranging from 16 to 26 dB, depending upon measurement times of the day.