On the Need for Coordinated Access Control for Vehicular Visible Light Communication

We argue on the need for a dedicated medium access control (MAC) for Vehicular VLC (V-VLC). The huge unlicensed spectrum that can support high throughput applications and the intrinsic security due to the LOS requirement make visible light a viable candidate for use in vehicular communications. In some first research work, the directionality of V-VLC has been considered and an initial conclusion was that the small collision domain leads to negligible interference and, thus, dedicated mechanisms for medium access are unnecessary. However, in a more realistic simulation setup using the Luxembourg mobility model, we are able to show that, in certain geographical areas, the number of transmitters seen at a single receiver can easily grow up to 30. Considering packet transmissions, the interference-induced packet loss can be substantial, reaching up to 13% during rush hours. We thus make the case that this packet loss should be mitigated with a dedicated MAC for coordinated access control in V-VLC.