VANET Clock Synchronization for Resilient DSRC Safety Applications

Vehicular Ad Hoc Networks ( VANET) are the fast-changing networks for connected vehicles, in which Vehiclet-o-Vehicle and Vehicle-to-Infrastructure communication are the basis for technologies aiming at reducing accidents and improving operation. DSRC Safety Applications, designed to assist drivers in order to avoid accidents, might be subjected to malicious attacks, such as GPS time spoofing attacks, which attempt to prevent time synchronization between vehicles. Failure of the centralized GPS-based clock synchronization has the potential to cause safety applications to fail. Therefore, decentralized clock synchronization can be a valuable approach for augmenting GPS-based clock synchronization. In this paper, a decentralized clock synchronization protocol for VANET is presented. The proposed protocol, based on approximate agreement, does not require any extra hardware nor modifications of any standards. The protocol was simulated using NS-3, and the results were analyzed and compared with previous synchronization protocols. The benefits of the proposed clock synchronization algorithm are higher resilience of safety applications to GPS spoofing attacks and when GPS signals are not available, such as in urban cities.