Intelligent reflecting surface (IRS) is a promising
technology to enhance the coverage and performance of wireless
networks. We consider the application of IRS to non-orthogonal
multiple access (NOMA), where a base station transmits superposed signals to multiple users by the virtue of an IRS. The
performance of an IRS-assisted NOMA networks with imperfect
successive interference cancellation (ipSIC) and perfect successive
interference cancellation (pSIC) is investigated by invoking 1-
bit coding scheme. In particular, we derive new exact and
asymptotic expressions for both outage probability and ergodic
rate of the m-th user with ipSIC/pSIC. Based on analytical
results, the diversity order of the m-th user with pSIC is in
connection with the number of reflecting elements and channel
ordering. The high signal-to-noise radio (SNR) slope of ergodic
rate for the m-th user is obtained. The throughput and energy
efficiency of IRS-NOMA networks are discussed both in delaylimited and delay-tolerant transmission modes. Additionally, we
derive new exact expressions of outage probability and ergodic
rate for IRS-assisted orthogonal multiple access (IRS-OMA).
Numerical results are presented to substantiate our analyses and
demonstrate that: i) The outage behaviors of IRS-NOMA are
superior to that of IRS-OMA and relaying schemes; ii) The M-th
user has a larger ergodic rate than IRS-OMA and benchmarks.
However, the ergodic performance of the m-th user exceeds
relaying schemes in the low SNR regime; and iii) The IRS-assisted
NOMA networks have ability to achieve the enhanced energy
efficiency compared to conventional cooperative communications