TAG: Trajectory Aware Geographical Routing in Cognitive Radio Ad Hoc Networks with UAV Nodes

Routing real-time packets in Cognitive Radio Ad Hoc Networks (CRAHNs) with mobile nodes is a challenging task. Mobile SUs can move into PU regions where the radio spectrum may not be accessible due to PU activity. In this case, real-time packets may be delivered to their destinations beyond their latency constraints. Unmanned Aerial Vehicles (UAVs) are mobile wireless ad hoc nodes that plan for their trajectory at any given time. In this paper, a Trajectory Aware Geographical (TAG) routing for CRAHNs with UAV nodes is proposed. TAG employs the trajectory information of UAVs and avoids selecting a UAV as a next hop if the UAV will fly inside a PU region or close to it. This strategy protects real-time packets from experiencing a long delay due to the PU activity. Our simulation results show that TAG effectively decreases the average end-to-end delay compared to Greedy geographical routing in the considered scenario.