Reflections in the Sky: Millimeter Wave Communication with UAV-Carried Intelligent Reflectors

Abstract

In this paper, a novel approach that uses an unmanned aerial vehicle (UAV)-carried intelligent reflector (IR) is proposed to enhance the performance of millimeter wave (mmW) networks. In particular, the UAV-IR is used to intelligently reflect mmW beamforming signals from a base station towards a mobile outdoor user, while harvesting energy from mmW signals to power the IR. To maintain a line-of-sight (LOS) channel, a reinforcement learning (RL) approach, based on Q-learning and neural networks, is proposed to model the propagation environment, such that the location and reflection coefficient of the UAV-IR can be optimized to maximize the downlink transmission capacity. Simulation results show a significant advantage for using a UAV-IR over a static IR, in terms of the average data rate and the achievable downlink LOS probability. The results also show that the RL-based deployment of the UAV-IR further improves the network performance, relative to a scheme without learning.

Smart Radio Environments Empowered by Reconfigurable Intelligent Surfaces: How It Works, State of Research, and The Road Ahead

“…In [229], the authors consider a UAV-carried RIS in order to enhance the performance of millimeter-wave networks. In particular, the UAV-carried RIS is used to intelligently reflect signals from a base station towards a mobile outdoor user, while harvesting energy from the signals so as to power the RIS.…”

Smart and Secure Wireless Communications via Reflecting Intelligent Surfaces: A Short Survey

“…Recently, flying RISs-assisted communications (UAVs equipped with an RIS) have received much attention. Some key features of flying RISs include 3D mobility, changeable direction and location, easy deployment, adaptive altitude, and power-efficient beamforming [63], [64]. The trajectory of a flying RIS can be optimized along with the phase shifts adjustment at the RIS elements for enhancing PLS [25].…”

On the Impact of Phase Shifting Designs on IRS-NOMA

“…R ECENTLY, intelligent reflecting surfaces (IRSs) have received significant attention, due to their ability to intelligently reconfigure wireless communication environments for better reception reliability at a low cost [1]- [4]. As a new energy and spectrally efficient technique, IRSs have been shown to be compatible with various advanced communication techniques, including millimeter-wave communications, unmanned aerial vehicle networks, physical layer security, and simultaneous wireless information and power transfer [5]- [7].…”