  Intelligent Reflecting Surfaces (IRS) are a promising solution to enhance the
coverage of future wireless networks by tuning low-cost passive reflecting
elements (referred to as {metasurfaces}), thereby constructing a favorable
wireless propagation environment. Different from prior works, which assume
Rayleigh fading channels and do not consider the direct link between a base
station and a user, this article develops a framework based on moment
generation functions (MGF) to characterize the coverage probability of a user
in an IRS-aided wireless systems with generic Nakagami-m fading channels in the
presence of direct links. In addition, we demonstrate that the proposed
framework is tractable for both finite and asymptotically large values of the
metasurfaces. Furthermore, we derive the channel hardening factor as a function
of the shape factor of Nakagami-m fading channel and the number of IRS
elements. Finally, we derive a closed-form expression to calculate the maximum
coverage range of the IRS for given network parameters. Numerical results
obtained from Monte-Carlo simulations validate the derived analytical results.
