Adaptive routing protocols for vehicular ad hoc networks

Vehicular ad hoc networks based on IEEE 802.11(WLAN) technology are emerging technologies for future Intelligent Transportation Systems (ITS). We investigate the behavior of routing protocols in vehicular networks by using microscopic mobility information based on the real road maps. The simulation results show the remarkable effect of the real mobility models on the performance of routing protocols. We observe a significant reduction in packet delivery ratio in traditional and even position based routing protocols. To address these performance limitations in vehicular networks, we propose several improvements and take into account special characteristics of vehicular networks. The major improvement is the use of link expiration time (LET) as a node mobility and density indicator to provide transmission range adaptation. We proposed two adaptive routing protocols for vehicular ad hoc networks and evaluated through simulation.