Intelligent Reflecting Surface Assisted Non-Orthogonal Multiple Access

Understand

Intelligent reflecting surface (IRS) is a new and disruptive technology to achieve spectrum- and energy-efficient as well as cost-efficient wireless networks.

• This paper considers an IRS-assisted downlink non-orthogonal-multiple-access (NOMA) system.
• To optimize the rate performance and ensure user fairness, we maximize the minimum decoding signal-to-interference-plus-noise-ratio (i.e., equivalently the rate) of all users, by jointly optimizing the (active) transmit beamforming at the base station (BS) and the phase shifts (i.e., passive beamforming) at the IRS.
• A combined-channel-strength based user ordering scheme is first proposed to decouple the user-ordering design and the joint beamforming design.