Visible light communications as a complementary technology for the internet of vehicles

- The paradigm of vehicular visible light network (VVLN) is introduced, highlighting its peculiarities, and discussing the present state of the art focusing on standardization and real experimentations.
- The limits of visible light communication (VLC) for pure VVLNs are discussed and its potentiality when used as complementary wireless technology is highlighted.
- An algorithm (called congestion-adaptive VLC-DSRC) is proposed to jointly manage VLC and dedicated short range communications (DSRC) in heterogeneous vehicular networks.
- Example results of VLC added to DSRC are shown focusing on the example application of crowd sensing vehicular networks (CSVNs) through simulations in realistic urban scenarios.

The paradigm of connected vehicles is moving from research to implementation, thus enabling new applications that start from safety improvement and widen to the so called Internet of vehicles (IoV). The candidate enabling technologies in the radio frequency (RF) bands are cellular and short range technologies. However, the limited bandwidth shared among several applications pushes researchers to look at new technological solutions. To this end, an option is provided by visible light communication (VLC). Based on the use of the light emission diodes (LEDs) that are already available on the majority of vehicles, VLC would enable short range communication in large, unlicensed, and uncongested bands with limited costs. In this work we first highlight the main properties of VLC in vehicular networks and revise the state of the art focusing on both the IEEE 802.15.7 standard and on the performance demonstrated by field tests that have been conducted worldwide. Then, we discuss the limitations of using VLC for pure vehicular visible light networks (VVLNs) and its application as complementary technology, to be implemented with other wireless standards in future heterogeneous vehicular networks. Finally, we show numerical results provided by simulations in a realistic urban scenario focusing, as a case study, on the crowd sensing vehicular network application with VLC added to short range IEEE 802.11p technology. Results demonstrate that the addition of VLC improves the performance of a conventional vehicular network based only on IEEE 802.11p.