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Links in vehicular networks are highly dynamic and generally exist only for a limited amount of time. Moreover, data packets are generally transmitted over multiple hops and have diverse latency requirements. The above situations together create a dilemma on the order/priority of the packets to be transmitted. However, the existing channel access mechanism of VANET does not critically consider the aforementioned aspects when granting channel access, and rather focuses on avoiding and resolving packet collisions. In order to bridge this gap, we present an improved channel access granting mechanism for data routing and scheduling via software defined vehicular networks (SDVN). We scrutinize the aforementioned parameters via a global perspective and utilize diverse channel modes cooperatively to maximize the delivery of data packets under delay tolerance and link connectivity regions. The primary problem is formulated as an integer linear programming (ILP) problem. The model avoids possible packet transmission conflicts via constraints while scrutinizing the wireless nature of links. Moreover, the proposed model is easily extended for the cooperative data communication under road side unit (RSU) application scenario. Furthermore, we present two computational improvement strategies based on incremental optimization and maximum independent sets (MIS) for the two application scenarios to shift the computational complexity to a realizable level for real-time communication. The effectiveness of the proposed routing and scheduling framework is comparatively evaluated with realistic mobility embedded road networks. |
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