Intelligent Reflecting Surface-Assisted Cognitive Radio System

Cognitive radio (CR) is an effective solution to improve the spectral efficiency (SE) of wireless communications by allowing secondary users (SUs) share spectrum with primary (PUs). Meanwhile, intelligent reflecting surface (IRS), also known as reconfigurable (RIS), has been recently proposed a promising approach enhance energy (EE) communication systems through intelligently reconfiguring channel environment. To both SE and EE, in this paper, we introduce multiple IRSs downlink multiple-input single-output (MISO) CR system, which single SU coexists network PU receivers (PU-RXs). Our design objective maximize achievable rate subject total transmit power constraint on transmitter (SU-TX) interference temperature constraints PU-RXs, jointly optimizing beamforming at SU-TX coefficients each IRS. Both perfect imperfect state information (CSI) cases are considered optimization. Numerical results demonstrate that IRS can significantly under CSI cases.