  Combining intelligent reflecting surface (IRS) and non-orthogonal multiple
access (NOMA) is an effective solution to enhance communication coverage and
energy efficiency. In this paper, we focus on an IRS-assisted NOMA network and
propose an energy-efficient algorithm to yield a good tradeoff between the
sum-rate maximization and total power consumption minimization. We aim to
maximize the system energy efficiency by jointly optimizing the transmit
beamforming at the BS and the reflecting beamforming at the IRS. Specifically,
the transmit beamforming and the phases of the low-cost passive elements on the
IRS are alternatively optimized until the convergence. Simulation results
demonstrate that the proposed algorithm in IRS-NOMA can yield superior
performance compared with the conventional OMA-IRS and NOMA with a random phase
IRS.
