An emergency message dissemination protocol using N-way search with power control for VANETs

Effectively broadcasting emergency messages in vehicular ad hoc networks (VANETs) is an important issue in VANETs. This paper proposes a Dynamic Search-Assisted Broadcast (DSAB) protocol to effectively broadcast emergency messages in VANETs. Dynamically adjusting the transmission power of control messages to estimate the vehicle density and appropriately adopting n-way search to find the farthest vehicle are the major techniques in DSAB protocol. To do so can not only find the best vehicle in the farthest segment to relay the emergency messages in the network, but also can reduce the interference among vehicles to save the network resource and increase the packet delivery ratio. Some mathematical analyses about time slot overhead in n-way search are done to support DSAB protocol in different vehicle densities. Based on the network simulations, the proposed protocol, DSAB, has a significant performance against the related work in one hop delay and packet delivery ratio.