Vertical Beamforming in Intelligent Reflecting Surface-Aided Cognitive Radio Networks

In this letter, we investigate joint application of intelligent reflecting surface (IRS) and vertical beamforming in cognitive radio networks (CRN). After properly modeling the network, an optimization problem is formed to jointly design the beamforming vector and tilt angle at the secondary base station (BS) as well as the phase shifts at the IRS with the objective of maximizing spectral efficiency of the secondary network. The optimization problem is non-convex; thus, we propose an efficient solution method for it. Numerical results show that adding an IRS and optimizing the radiation orientation, can significantly improve performance of the CRNs.