Enhancing Cellular Communications for UAVs via Intelligent Reflective Surface

Abstract

Intelligent reflective surfaces (IRSs) capable of reconfiguring their electromagnetic absorption and reflection properties in real-time are offering unprecedented opportunities to enhance wireless communication experience in challenging environments. In this paper, we analyze the potential of IRS in enhancing cellular communications for UAVs, which currently suffers from poor signal strength due to the down-tilt of base station antennas optimized to serve ground users. We consider deployment of IRS on building walls, which can be remotely configured by cellular base stations to coherently direct the reflected radio waves towards specific UAVs in order to increase their received signal strengths. Using the recently released 3GPP ground-to-air channel models, we analyze the signal gains at UAVs due to the IRS deployments as a function of UAV height as well as various IRS parameters including size, altitude, and distance from base station. Our analysis suggests that even with a small IRS, we can achieve significant signal gain for UAVs flying above the cellular base station. We also find that the maximum gain can be achieved by optimizing the location of IRS including its altitude and distance to BS.

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

“…In [227], the authors consider the deployment of RISs on the walls of buildings and assume that they can be remotely configured by cellular base stations in order to coherently direct the reflected radio waves towards specific UAVs for increasing the received signal strength. By using standardized ground-to-air channel models, the authors analyze the signal gain at the UAVs, as a function of the height of the UAVs, and the size, altitude, and distance from base station of the RIS.…”

Joint Beamforming and Trajectory Optimization for Intelligent Reflecting Surfaces-Assisted UAV Communications

“…A reinforcement learning approach is proposed in [5] to model the propagation environment to optimize the location and reflection coefficient of UAV-IRS. The authors in [7] analyze the signal gains at UAVs as a function of their heights as well as various IRS parameters. However, there is only one IRS employed in these studies which limits the improvement of system performance.…”

“…To address these challenges, intelligent reflecting surface (IRS) has been recently proposed to bypass obstacles and enhance communications in UAV systems, namely IRS-assisted UAV communications [5]- [7]. According to the IRS-assisted UAV framework, multiple IRSs are deployed in the open air to assist the communication between UAV and users.…”

Reconfigurable Intelligent Surfaces for Smart Cities: Research Challenges and Opportunities

“…Outdoors, the target application would be Smart City. So far, however, only a few works have investigated RIS-assisted outdoor scenarios [22], [23]. The main innovation addressed in these works is the use of unmanned aerial vehicles (UAVs).…”