Downlink and Uplink Intelligent Reflecting Surface Aided Networks: NOMA and OMA

Yanyu Cheng, Kwok Hung Li, Yuanwei Liu, Kah Chan Teh, H. Vincent Poor

Research output: Contribution to journalArticlepeer-review

120 Scopus citations


Intelligent reflecting surfaces (IRSs) are envisioned to provide reconfigurable wireless environments for future communication networks. In this paper, both downlink and uplink IRS-aided non-orthogonal multiple access (NOMA) and orthogonal multiple access (OMA) networks are studied, in which an IRS is deployed to enhance the coverage by assisting a cell-edge user device (UD) to communicate with the base station (BS). To characterize system performance, new channel statistics of the BS-IRS-UD link with Nakagami-$m$ fading are investigated. For each scenario, the closed-form expressions for the outage probability and ergodic rate are derived. To gain further insight, the diversity order and high signal-to-noise ratio (SNR) slope for each scenario are obtained according to asymptotic approximations in the high-SNR regime. It is demonstrated that the diversity order is affected by the number of IRS reflecting elements and Nakagami fading parameters, but the high-SNR slope is not related to these parameters. Simulation results validate our analysis and reveal the superiority of the IRS over the full-duplex decode-and-forward relay.

Original languageEnglish (US)
Article number9345507
Pages (from-to)3988-4000
Number of pages13
JournalIEEE Transactions on Wireless Communications
Issue number6
StatePublished - Jun 2021
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Applied Mathematics


  • Intelligent reflecting surface
  • non-orthogonal multiple access
  • orthogonal multiple access


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