The growing need for wireless connection, as well as the advent of the concept of the Internet of Things, necessitate the development of new communication paradigms that will, in turn, enable a multitude of new applications and disruptive technologies. The current contribution investigates the use of the recently introduced intelligent reflecting surface (IRS) concept in unmanned aerial vehicle (UAV) enabled communications with the goal of extending network coverage and improving communication reliability as well as spectral efficiency of Internet of Things (IoT) networks. We begin by obtaining tractable analytic formulas for the feasible symbol error rate (SER), ergodic capacity, and outage probability of the given setup. We then construct stringent upper and lower constraints for the average signal-to-noise ratio (SNR). Our derivations are then compared to the related asymptotic performance, which demonstrates that the asymptotic SNR lies inside the region between the derived bounds, and approaches either bound depending on the number of reflecting elements (REs). The provided findings show that using the IRS is very effective, as they help to improve the attainable SER by five orders of magnitude. We also show that IRSassisted UAV communication systems can have ten times the capacity of traditional UAV communications in terms of attainable ergodic capacity.
