  In this work, we study the outage probability (OP) at the destination of an
intelligent reflecting surface (IRS) assisted communication system in the
presence of phase error due to quantization at the IRS when a)
source-destination (SD) link is present and b) SD link is absent. First,an
exact expression is derived and then we derive three simple approximations for
the OP using the following approaches: (i) uni-variate dimension reduction,
(ii) moment matching and,(iii) Kullback-Leibler divergence minimization. The
resulting expressions for OP are simple to evaluate and quite tight even in the
tail region. The validity of these approximations is demonstrated using
extensive Monte Carlo simulations.
