Directed broadcasting with mobility prediction for vehicular sensor networks

This article suggests a new directed broadcasting method with mobility prediction of moving vehicles in vehicular sensor networks (VSNs). VSNs can play a critical role to ensure prompt delivery of real-time sensing data and be able to prevent various road dangers. The suggested method is particularly for vehicle safety communication (VSC) on highway roads by using directed broadcasting between vehicles. In VSNs, broadcasting is the most suitable communication mechanism for VSC. The simplest broadcasting mechanism is flooding, which introduces the redundant message retransmission and the broadcast storm problem. It is because all vehicles rebroadcast the messages in flooding. The broadcast storm problem can be addressed with selective flooding schemes which select rebroadcast vehicles to perform rebroadcasting. However, selective flooding schemes cannot promise enough reliability for VSC because of the highly dynamic topology and frequent disconnections of vehicular networks. Fast movement and frequent topology changes cause repeated link breakages and it increases the packet loss rate of vehicular networks. In this article, we propose a mobility prediction-based directed broadcasting (MPDB) protocol to achieve a reliable broadcasting in VSNs. MPDB protocol broadcasts emergent messages only to the rear vehicles on the same road. MPDB protocol consists of two phases: (i) mobility prediction phase and (ii) broadcasting phase. The mobility prediction can be acquired through periodical beaconing. In mobility prediction phase, each vehicle gets its rear vehicle set on the same road through neighbour’s position, inter-vehicle distance, relative speed and moving direction. In broadcast phase, MPDB protocol selects a vehicle having the largest link available time (LAT) values acquired by the mobility prediction as a rebroadcast vehicle among the rear vehicle set acquired in previous phase. By using LAT for broadcasting propagation, MPDB protocol can intensify the reliability of the message dissemination and also prevent the broadcast storm problem in vehicular networks. The simulation results show that MPDB protocol has better performance improvement in terms of average packet rate and packet delay.