# Vehicular Visible Light Communication for Intersection Management +
## 2 Related Works  
Vehicular networking applications can take advantage of the LED-equipped lighting modules and transportation infrastructure to realize vehicular visible light communication (V-VLC). In this work, the communication and geolocation are performed exclusively by VLC using the streetlamps, the traffic signaling and the head and tail lamps, enabling the dual use of exterior automotive and infrastructure lighting for both illumination and communication purposes. In [13], a VLC prototype suitable only for I2V communication is presented. The system consists of a regular traffic light as a transmitter (the red light is modulated with the information), and a photodetector with Fresnel lenses as a receiver. The traffic light transmits messages to the vehicle, which decodes them. Special emphasis is put on the optics of the photodetector. In [14], experimental measurement was carried out also by using a regular traffic light as source (red light) and a photoreceiver positioned at different distances along the road. Special emphasis was put on the model of the transmission pattern and propagation of the VLC signal. In [15], the problem of interference in a realistic urban scenario was analyzed, and a temporal and spatial hotspot for collisions in V-VLC is established. A heterogeneous crosslayer MAC protocol for V-VLC communication was also proposed. Realistic simulations of vehicles' mobility and V-VLC channel (V2V) are presented. Special emphasis was put on the design of the protocol and on the division of the radiation pattern of lighting modules into multiple sectors. GPS positions for the vehicles and RF transmissions to advertise them were used together with the VLC communication between the vehicles. In [3, 16, 17], our goal was to present a cooperative I2V2V2I2V system that supports guidance services and uses an edge/fog-based architecture able to safely manage vehicles crossing through a split intersection. Only visible light communication is used to transmit and receive information. This makes our work different from the others. Here, the streetlights and traffic lights, through VLC, report its geographical positions and specific information to the drivers since its infrastructure can also be reused to embed the edge/fog nodes in them. Using an edge-fog based architecture, an Intersection Manager (IM) can increase the throughput of the intersection by exchanging information with and directing incoming CAVs. Using joint transmission from the white tetra chromatic streetlights, mobile optical receivers collect data, calculate their location for positioning and, concomitantly, read the transmitted data from each transmitter. As receivers and decoders, SiC pinpin optical sensors with light-filtering properties are used. Bidirectional communication between the infrastructure and the vehicles was tested. To command the passage of vehicles safely, queue/request/response mechanisms and temporal/space relative pose concepts are used. In [16] special emphasis was put color phasing diagram and, on the request/response mechanism to define the color pose. As PoC the movement of the cars with their colorful poses and spatial relative poses were experimentally evaluated. In [3, 17] the main emphasis is put in the architecture and in the multi-vehicle localization. An indirect V2V relative pose estimation method was proposed and a phasing diagram for the split intersection presented. In this paper, queue/request/response mechanisms and temporal/space relative pose concepts are extended, polished and dynamically adjusted. Vehicle movement along the road takes the form of a queue, where the vehicles arrive at a lane, wait if the lane is congested and then move once the congestion reduces. Cooperative localization is realized in a distributed way with the incorporation of the indirect V2V relative pose estimation method. The vehicle gathers relevant data from neighboring vehicles and estimates the relative pose of them using the indirect V2V relative pose [18, 19].