MobiT: A Distributed and Congestion-Resilient Trajectory Based Routing Algorithm for Vehicular Delay Tolerant Networks

Packet routing is important for Vehicular Delay Tolerant Networks (VDTNs).Opportunistic routing algorithms based on historical records are insuciently accurate in forwarder selection due to movement randomness of vehicles. Trajectory-based routing algo- rithms tackle vehicle movement randomness but cannot be directly used in VDTNs due to the dependence on APs. In this paper, we develop a distributed trajectory-based routing algorithm (called MobiT) for VDTNs.is non-trivial task faces three challenges. First, vehicle trajectories must be suciently collected. Second, the trajectories cannot be updated frequently due to limited resources of the repository nodes. ird, achieving high routing performance even with partially collected trajectories. Our real trace study lays the foundation of the design of MobiT. Taking advantage of dier- ent roles of vehicles, MobiT uses service vehicles that move in wide areas to collect vehicle trajectories, and rely on the service vehicles and roadside units (called schedulers) for routing scheduling. By using regular temporal congestion state of road segments, MobiT schedules the packet to arrive at a roadside unit prior to the des- tination vehicle to improve routing performance. Further, MobiT leverages vehicles' long-term mobility paerns to assist routing. Extensive trace-driven and real experiments show the eectiveness and eciency of MobiT.