Bi-directional Communication between Infrastructures and Vehicles through Visible Light

In this paper a vehicular communication system that incorporates illumination, signaling, communications, and positioning functions is presented. The bidirectional communication between the infrastructures and the vehicles (I2V), between vehicles (V2V) and from the vehicles to the infrastructures (V2I) is performed through Visible Light Communication (VLC) using the street lamps and the traffic signaling LEDs to broadcast the information. As receivers and decoders, pin/pin SiC Wavelength Division Multiplex (WDM) photodetectors, with light filtering properties, are being used. White polychromatic-LEDs are used for lighting and to implement the WDM. This allows modulating separate data streams on four colors which together multiplex to white light. A traffic scenario is proposed, along with the transmitter to receiver setup. The performance of a cooperative driving system is evaluated. To achieve cooperative vehicular communications (I2V2V2I2V), streams of messages containing the ID physical address of the emitters are used, transmitting a codeword that is received and decoded by the receivers. As a proof of concept, a I2V2V2IV traffic scenario is presented, bidirectional communication between the infrastructures and the vehicles is established and tested. The experimental results confirm that the cooperative vehicular VLC architecture is a promising approach concerning communications between road infrastructures and cars, fulfilling data privacy.