Parking-Area-Assisted Spider-Web Routing Protocol for Emergency Data in Urban VANET

In urban vehicular ad-hoc networks (VANET), owing to the high mobility and uneven distribution of vehicles, the rapid and reliable transmission of emergency data is a challenging task. Some bio-inspired intelligent routing protocols are effective in transmitting emergency data. However, their computational complexity and convergence speed may result in large delays. Furthermore, it has been demonstrated that parked vehicles may be used as relay nodes and thus facilitate data packet transmission in VANET. In this paper, we propose a parking-area-assisted spider-web routing protocol (PASRP) for emergency data in urban VANET. In PASRP, a spider-web transmission model is established based on the parking area by using a geographic information system and a digital map. Two control messages, request-spider and confirm-spider, are sent to obtain the transmission path from the source vehicle to the destination vehicle, and the path with the least delay is selected as the transmission path. Then, the emergency data are forwarded on the selected path using a multi-mode greedy algorithm and are prioritized by a dynamic multi-priority scheduling mechanism. Finally, the simulation results demonstrate that the proposed PASRP outperforms the existing greedy perimeter stateless routing and transmission mechanism for emergency data protocols.