Connected cars: Road-to-vehicle communication through visible light

A safe smart vehicle lighting system that combines the functions of illumination, signaling, communications, and positioning is presented. The 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. Vehicle headlamps are used to transmit data to other vehicles or infrastructures (traffic lights) allowing digital safety and data privacy. As receivers and decoders, pin/pin SiC Wavelength Division Multiplex (WDM) photodetectors, with light filtering properties, are being used. We propose the use of white polychromatic-LEDs to implement the WDM. This allows modulating separate data streams on four colors which together multiplex to white light. When a probe vehicle enters the infrastructure's capture range, the receivers respond to light signal and the infrastructure ID and traffic message are assigned. They perform simultaneously the V2V distance measurement and data transmission functions and, using the headlamps, resend the data to the other vehicles or to the traffic signals (V2I). A I2V2V2I traffic scenario is stablished. A vulnerable road user case that covers pedestrians, cyclists and wheelchairs is also considered. A phasing traffic flow is developed as a Proof of Concept (PoC). The experimental results confirm that the cooperative vehicular VLC architecture is a promising approach concerning communications between road infrastructures and cars, fulfilling data privacy.