In this letter, we analyze the performance of the intelligent reflecting
surface (IRS) assisted downlink non-orthogonal multiple access (NOMA) systems
in the presence of imperfect phase compensation. We derive an upper bound on
the imperfect phase compensation to achieve minimum required data rates for
each user. Using this bound, we propose an adaptive user pairing algorithm to
maximize the network throughput. We then derive bounds on the power allocation
factors and propose power allocation algorithms for the paired users to achieve
the maximum sum rate or ensure fairness. Through extensive simulations, we show
that the proposed algorithms significantly outperform the state-of-the-art
algorithms
