Adaptive vehicular routing protocol based on ant colony optimization

Vehicular Ad hoc Networks (VANETs) pose many challenges to cope with, such as large network size, rapid topology changes and channel capacity limitations. To address these problems, we propose VACO (Vehicular routing protocol based on Ant Colony Optimization), a new adaptive multi-criteria VANET routing protocol. VACO combines both reactive and proactive components to respectively establish and maintain best routing paths. Reactive forward and backward ants are sent between source and target intersection (closest intersection to the destination vehicle) to explore and set up best routes consisting of a list of intersections. Routing decision is then realized at each intersection to opportunistically select best next intersection. The key feature of the route selection is to rely on a periodically estimated road segment relaying quality which is expressed in terms of three combined QoS parameters (latency, bandwidth and delivery ratio). The derived simulation results indicate that VACO shows better performance than a basic geographical routing protocol (GPSR) and a min-delay routing protocol (CAR).