DVS: A distributed virtual signboard for information dissemination and preservation in vehicular networks

With increasing affluence and growing urban populations, traffic congestion is a world-wide problem and affects almost everybody. One way to mitigate this problem is to provide real-time traffic information to drivers. This will allow them to make better travel and navigation decisions, such as avoiding congested areas or getting out of blocked lanes. In this paper, we consider a fully distributed information access, dissemination and preservation protocol for road traffic conditions called the Distributed Virtual Signboard (DVS). The DVS disseminates real time local traffic information to drivers to alert them of possible disruptions, and keeps the information alive in the relevant area, in a fully distributed fashion. It provides a low cost and widely applicable solution because it does not require any dedicated roadside infrastructure. The DVS uses traffic in both directions on the road, to form a virtual information loop. Specifically, a double token ring is implemented to increase the information delivery ratio and to increase the robustness of the whole scheme. Analysis shows that, when congestion happens, which is normally associated with a situation of high car density, the probability of token handover failure is close to zero. We have also shown that, almost all cars passing through the virtual loop can get the traffic alert under DVS.