VLCS: A Novel Clock Synchronization Technique for TDMA-based MAC Protocols in VANETs

Local clock synchronization of nodes is one of the most critical problems with Time-Division Multiple Access (TDMA)-based protocols for dissemination of warning messages in Vehicular Ad hoc Networks (VANETs). Unsynchronized nodes' clocks make time slot reservations inefficient, which results in channel collisions at a large scale. In this paper, we propose a novel cluster-based Vehicle-to-Vehicle Local Clock Synchronization (VLCS) technique, which is composed of two phases to synchronize all nodes in a VANET to a commonly shared clock. The first phase performs inter-cluster clock synchronization, whereas the second phase accomplishes intra-cluster clock synchronization where each member node synchronizes its clock with the corresponding cluster head. Simulation results demonstrate significant improvement of VLCS over an eminent VANETs clock synchronization technique.