An Emergency Warning Message Dissemination Policy of Vehicular Ad Hoc Network

In vehicular ad hoc network, emergency warning messages exchange could improve vehicle safety. Emergency warning messages should be exchanged with high reliability and low delay. Currently, reliability of emergency warning messages is guaranteed by repeating broadcast. In current research, how many times repeated broadcast per second was not discussed. In this paper, a speed-based broadcast rate model is proposed. The main idea of the method was to model the message creation and broadcast system as a queuing system. With the relationship model of vehicle speed and message creation number was established, and the transfer delay of emergency message was limited, the basic model to calculate the optimized repeating broadcast rate was proposed. Experiment results showed that the method had balanced reliability and transfer delay of emergency message broadcast with simple operation.