Phase Transition of Message Propagation Speed in Delay Tolerant Vehicular Networks
Delay Tolerant Network (DTN) architectures have recently been proposed as a means to enable efficient routing of messages in Vehicular Area NETworks (VANETs), which are characterized by alternating periods of connectivity and disconnection. Under such architectures, when multi-hop connectivity is available, messages propagate at the speed of radio over connected vehicles. On the other hand, when vehicles are disconnected, messages are carried by vehicles and propagate at vehicle speed. The authors' goal in this paper is to analytically determine what gains are achieved by DTN architectures and under which conditions, using average message propagation speed as the primary metric of interest.