Vehicular ad hoc networks(VANETs) that use the IEEE 802.11 p communication standard face a number of challenges,not least when it comes to safety messages on the VANET control channel(CCH) where short delay times and reliable delivery are of primary importance.In this paper we propose a vehicular machine-to-machine(VM2M) overlay network that uses Long Term Evolution(LTE) physical random access channel(PRACH) to emulate VANET CCH.The overlay network uses dedicated preambles to separate vehicular traffic from regular LTE traffic and a carrier sense multiple access with collision avoidance(CSMA-CA) layer similar to the one used in IEEE 802.15.4 to avoid the four step handshake and the overhead it incurs.The performance of the proposed overlay is evaluated under a wide range of PRACH parameters which conform to the scenarios with high vehicle velocities and large distances between roadside units(RSUs) that may be encountered in rural areas and on highways.
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