Joint Active and Passive Beamforming in IRS-assisted Wireless Networks Over Generalized Fading Model

Abstract

Intelligent Reflecting Surface (IRS), a promising future wireless technology, aims to mitigate the vulnerability of the blockage caused by significant propagation attenuation by creating intelligent radio environments, enhancing spectrum efficiency, and improving coverage capacity and inadequate diffraction of terahertz (THz) waves. The IRS modifies the phase shifts of passive reflecting components to manage the propagation of incoming electromagnetic waves in a programmable way. In this paper, we aim to study joint active and passive beamforming in an multiple-input single-output (MISO) downlink single user scenario in a generalized fading model. To optimize the user's received signal power, joint active and passive i.e., transmit and reflect beamforming is employed. By considering the CSI is present at the IRS, the technique semidefinite relaxation (SDR) is used. Owing to the importance of generalized fading models, in this work we considered $\kappa-\mu$ fading channel to capture its effect on joint active-passive beamforming. A thorough analysis indicates that the received signal-to-noise ratio is largely influenced by the characteristics of signal fading. The obtained results will be helpful in analysing the augumented performance of IRS-aided communication system in a generalized manner over the traditional setup without IRS.