Alert service in VANET: Analysis and design

This paper focuses on inter-vehicular networks providing warning delivery service. As soon as a danger is detected, the propagation of a warning message is triggered, with the aim of guaranteeing a safety area around the point in which the danger is located. The service is based on multi-hop ad hoc inter-vehicular communications with a probabilistic choice of the relay nodes. The scenario we consider consists of high speed streets, such as highways, in which vehicles exhibit one-dimensional movements along the direction of the road. We propose an analytical model for the study of this service and derive performance indices such as the probability that a vehicle is informed, and the average number of duplicate messages received by a vehicle. Moreover, we use the model to discuss system design issues, which include the proper setting of the flooding probability at each vehicle so that a given probability to receive the warning can be guaranteed to all vehicles in the safety area around the danger point. The model is validated against simulation results and, thanks to the high level of accuracy, can be instrumental to the performance evaluation and design of broadcasting techniques in inter-vehicular networks.