LRF: Location-based Reverse Forwarding for Infrastructure-to-Vehicle Data Delivery

In this paper, a scheme is proposed to support Infrastructure-to-Vehicle (I-to-V) data delivery in vehicular ad hoc networks (VANETs) for reporting of road condition information such as holes, bumps, partial flooding, land sliding, mud sliding, fog, dust storms, construction accidents, icy roads or road pre-warning such as accidents/skidding. This information will be highly useful for motorists which are at some distance away from the accident/hazard site in order to give them an opportunity to modify their trajectory (if possible) or become alerted/warned about the impending hazard. The proposed scheme can not only alert the approaching vehicles but also can be beneficial for quickly updating variable-message signs with messages to avoid or slow down because of some accident/hazard ahead in the vehicle path. The proposed scheme is based on the simple idea of "Region-of-Interest" which can be defined as the area in a certain radius of the accident/hazard site with roads and intersections which are going to be severely affected due to the accident. The proposed scheme uses multi-hop data forwarding utilizing wireless sensors, roadside units and traffic management centers to directly deliver messages to on-board units fitted in cars entering from specific entrance points. For those cars which are not yet fitted with on-board units, the roadside units will forward the same information to electronic variable-message signs which are in close proximity of the accident/hazard site.