Analysis of delay distribution for downstream message deliveries in sparse VANETs

Vehicular ad hoc network (VANET) has widely been considered as a promising wireless networking technology to provide a variety of services or applications for the development of intelligent transportation systems (ITS). Messages are delivered between vehicles in a VANET for exchanges or updates of information. However, a sparse VANET may frequently suffer from network disconnections. In this paper, the routing of downstream messages in network disconnections is discussed, and the distribution of the delay incurred during the restoration of a network disconnection is calculated, where the Laplace transform and the inverse Laplace transform are utilized to calculate the distribution of the sum of random variables. Numerical results show that our proposed analysis provides better accuracy in predicting the end-to-end delay of a connection that may contain more than one network disconnection.