  In this letter, the impact of two phase shifting designs, namely random phase
shifting and coherent phase shifting, on the performance of intelligent
reflecting surface (IRS) assisted non-orthogonal multiple access (NOMA) is
studied. Analytical results are developed to show that the two designs achieve
different tradeoffs between reliability and complexity. Simulation results are
provided to compare IRS-NOMA to conventional relaying and IRS assisted
orthogonal multiple access, and also to verify the accuracy of the obtained
analytical results.
