An eMBMS based congestion control scheme in cellular-VANET heterogeneous networks

In the IEEE 802.11p network, vehicles are required to periodically broadcast beacon messages to provide interactive awareness among vehicles. However, a constant and high beacon rate may result in channel congestion, which prevents the event-driven messages to be disseminated in time. Considering the fact that point-to-multipoint (PtM) transmission technologies, which can efficiently utilize limited wireless resource, have been well studied and standardized in modern cellular systems. In this paper we propose an effective heterogeneous solution to solve the congestion control problem in vehicular ad-hoc networks (VANETs) with the support of enhanced Multimedia Broadcast Multicast Services (eMBMS) in LTE cellular systems. Specifically, we propose to adapt vehicles´ beacon rates based on the emergency messages multicast update rate in eMBMS. By this means, timely dissemination of event-driven messages can be guaranteed and the average packet delivery ratio (PDR) in IEEE 802.11p VANET can be improved. Through simulations, we exhibit the integrated performance gains by combining the advantages of two heterogeneous networks.