Joint Trajectory Design and Power Allocation in NOMA-Based UAV Networks

The employment of the unmanned aerial vehicle (UAV) as communication platform has drawn a lot of interest recently. Although previous studies have presented the performance gain by utilizing the UAV's mobility and communication, they concentrate on the UAV trajectory for homogeneous devices with the same requirements of data size and latency constraints. The UAV trajectory for groups with heterogeneous devices can affect the UAV's service capabilities. Additionally, the technique of non-orthogonal multiple access (NOMA) has been deemed as a promising technique in future communication networks since it can improve the spectral efficiency and support more device connections. The UAV can integrate with NOMA to further enhance the situation. In this article, we consider a NOMA-based UAV system, where a UAV provides services to ground devices in different groups. We aim to maximize the total throughput under the constraints of data rate, sum transmit power, and atomicity of devices' tasks. To tackle this problem, we first derive the closed-form expression of transmit power based on Karush-Kuhn-Tucker (KKT) conditions. Then, we formulate a group-based auction algorithm to decide the service order of UAV to device groups, where a latency estimation algorithm is constructed to design the auction bidding. Additionally, an adaptive device admission algorithm is put forward to settle the device scheduling problem within one group. Numerical results show that our proposed scheme acquires a significant performance gain in terms of the total throughput, compared with other benchmark schemes.