Resource Allocation in Cognitive Radio-Enabled UAV Communication

The deployment of unmanned aerial vehicles (UAVs) in wireless communications will be constrained in practice by the unavailability of frequency spectrum. Cognitive radio techniques are viewed to offer promising solutions in which a secondary UAV-based network can operate in a frequency band licensed to an existing terrestrial wireless network with minimal interference. We investigate the performance of a cognitive radio-enabled UAV network configuration in which the UAV is allowed to communicate with secondary ground terminals (SGTs) in the underlay mode in the licensed spectrum band. Optimization of the performance of the secondary network is considered in terms of maximizing the total throughput of the network subject to satisfying two constraints. The first constraint is imposed to prevent interference with the primary network while the second constraint ensures that the throughput requirement of each SGT is met. A probabilistic channel model is assumed. The Variables to be determined include the transmission power, the channel time allocations to the SGTs and the route and coordinates of the stationary locations in space in which the UAV will hover and transmit. A heuristic approach is developed in order to arrive at solutions to this extremely complex optimization problem and results of numerical simulations are presented.