Performance Analysis of IRS Assisted Underlay Cognitive Radio Networks

In this paper, the performance of an intelligent reflecting surface (IRS) assisted underlay point-to-point communication has been analyzed. The role of an IRS is well established to defy the limitations of deep fade channels by modifying the channel characteristics. Use of IRS is well motivated in case of underlay cognitive radio network framework, since they constrain the transmit powers to ensure that the interference limit to the primary user. In this paper, a secondary base station transmits its information signal to a secondary destination via an IRS in underlay fashion. Analysis of outage probability and ergodic capacity is carried out in this paper. A closed form expression for outage probability and outage floor has been derived. Also, the diversity order of the system has been derived to showcase the advantage of the IRS and it comes out to 80.5% of the total number of IRS elements. Monte-Carlo simulations are carried out to verify the derived results.