Adaptive Beaconing Rate Based Stopping Distance

The Intelligent Transportation Systeim (ITS) utilizes Vehicle-to-Vehicle (V2V) and Vehicle-to-Roadside (V2R) communication, enabled by Vehicular Ad Networks (VANETs), to implement many traffic safety application. Vehicles and Road Side Units (RSUs), in VANETs, periodically broadcast messages, known as beacons, contain many vehicle’s driving parameters such as current position, direction, speed, road conditions, etc. To receive the broadcasted driving information, vehicles listen to the control channel. The accuracy of the traffic safety application depends on the rate at which the beacons are broadcasted. Higher broadcast rate of beacons, can help obtain close to instantaneous driving information. Increasing the beacon rate for all vehicles on the road can increase the channel congestion which then can lead to higher beacon collision rate. In this work we propose Adaptive Beaconing Rate Protocol (ABRP) which adapts the beaconing rate of vehicles based on their driving parameters change rate. In this paper we set the beaconing rate proportional to the stopping distance. Stopping distance estimation depends on many factors: vehicles speed, weight, size, road fraction coefficient, etc. Hence, setting the beacon rate proportional to stopping distance means that all the aforementioned factors are included in adapting the beaconing rate. To evaluate the proposed scheme, by using OPNET Modeler, we created a detailed highway scenario. The obtained results shows that ABRP scheme outperforms the fixed beaconing rate in terms of medium access delay, delivered ratio, and collision rate. 