Optimal Contention Window size for beaconing in VANETs

Vehicular applications, such as traffic safety applications used to increase the road safety and traffic efficiency applications used to decrease the traffic jams are mainly supported using VANETs (Vehicular Ad-hoc Networks). An important VANET feature is beaconing. This paper uses simulation experiments to analyze how the reception probability of beacons can be increased by optimizing the Contention Window (CW) size. From these experiments it can be concluded that the combination of the contention window size and the number of vehicles using the same VANET radio channel has an impact on beaconing reception probability. In particular, by increasing the CW size and the number of vehicles, the beaconing reception probability is decreased. Moreover, the currently used initial CW maximum value (i.e. 15) applied for beaconing is the best selected value.