Joint beamforming and power allocation for wireless powered UAV-assisted cooperative NOMA systems

• Main Author: Guangchen Mu
• Format: Article
• Language: English
• Published: SpringerOpen 2020-03-01
• Series: EURASIP Journal on Wireless Communications and Networking
• Subjects: Unmanned aerial vehicle (UAV); Non-orthogonal multiple access (NOMA); Simultaneous wireless information and power transfer (SWIPT); Full-duplex relay
• Online Access: http://link.springer.com/article/10.1186/s13638-020-01667-8

Abstract In this paper, we investigate an unmanned aerial vehicle (UAV)-enabled non-orthogonal multiple access (NOMA) systems, where UAV acts as a full-duplex (FD) relay to help the communication between the base station (BS) and two NOMA users. Assume that the UAV follows a circular trajectory and applies decode-and-forward (DF) strategy. Using simultaneous wireless information and power transfer (SWIPT), the UAV harvests energy from the BS in the first time slot and self-interference due to FD mode in the second time slot. By the joint optimization of beamforming and time allocation ratio, we aim at maximizing sum throughput of the whole system and harvested energy at UAV. To solve two highly non-convex problem, we propose the corresponding algorithms based on inner approximation method, respectively, which can converge to at least optimal solutions in few steps. In terms of two different system performances, numerical results can verify that the effectiveness of the proposed scheme. We also find the optimal azimuth angle of UAV’s circular trajectory by simulation.