Data Dissemination for Vehicles in Temporary Cellular Network Dead Spots

The cellular network coverage in sparsely populated and mountainous areas is often patchy. That can be a significant impediment for services based on connections between vehicles and their environment. This article presents a method to reduce the waiting time occurring when a vehicle intends to send a message via a cellular network but is currently in a dead spot, i.e., an area without sufficient coverage. The authors introduce a data dissemination protocol that allows vehicles to connect through an ad-hoc network. The ad-hoc network peers can then find out which one will most likely leave the dead spot first. The selected vehicle stores then the messages of all connected vehicles and forwards them to the remote infrastructure as soon as it regains cellular network access. This research also discusses message flows in larger dead spots in which a vehicle may consecutively form several ad-hoc connections. Further, the authors describe an initial implementation of the protocol using the technology Wi-Fi Direct that is realized on most modern mobile phones.