A Light Traffic Load and Highly Reliable Emergency Message Broadcasting Mechanism for VANETs

In Vehicular Ad-hoc Networks (VANETs), nodes are equipped to collaboratively broadcast emergency messages in case of any transportation emergence events, which can improve the road safety. However, heavily repeated rebroadcasting of messages leads to severe redundancy and collisions, bringing in inefficient channel utilization and low reliability. In order to improve this issue, we propose a probabilistic rebroadcast method to reduce the traffic load caused by repeated rebroadcasting of a same message. Instead of transmitting an emergency message once receives one, a node broadcasts under a certain probability, which is determined according to the node density, traveling velocity, and the distance of the node itself to the source node. Moreover, a waiting process is applied to eliminate the collisions caused by simultaneous broadcasting from multiple nodes. Through extensive simulations, we demonstrate that proposed mechanism can effectively reduce traffic loads and alleviate transmission collisions.