Bi-Beacon: Two-level power control for enhancing beacon performance in vehicular ad hoc networks

Vehicular ad hoc networks (VANETs) support safety applications to prevent car accidents. Beacons are periodically broadcasted for various safety applications but very sensitive to collision and delay. In this paper, we propose a new transmission scheme, called Bi-Beacon, which transmits two levels of power to reduce collision and maintain maximum transmission range. High collision problem still remains in high vehicle density condition and contention window (CW) control with Bi-Beacon reduces collision but results in larger delay time. We propose a new beacon update scheme which reduces delay time in high density condition.