Hybrid Uplink and Downlink Transmissions for Full-Duplex UAV Communication With RIS
Kaiyuan Tian, Bin Duo, Sixian Li, Yong Zuo, Xiaojun Yuan
Abstract
This letter proposes a reconfigurable intelligent surface (RIS)-aided full-duplex unmanned aerial vehicle (FD-UAV) communication system. The FD-UAV performs its mission to communicate with an uplink (UL) user and a downlink (DL) user simultaneously over the same time-frequency dimension. The RIS is deployed to enhance the signal strength to the UL and DL users while suppressing the co-channel interference (CCI) from the user side. We aim to maximize the weighted sum rate of UL and DL transmissions by jointly optimizing the transmit power of the UL user, RIS’s phase-shift, and UAV trajectory. Although the formulated problem is difficult to solve due to its joint non-convexity, we propose an efficient algorithm based on the successive convex approximation and fractional programming techniques to solve the problem suboptimally. Simulation results show that the proposed RIS-aided communication system can achieve a significant sum rate gain over various bechmark schemes.