Exploiting Intelligent Reflecting Surfaces in NOMA Networks: Joint Beamforming Optimization

Understand

This paper investigates a downlink multiple-input single-output intelligent reflecting surface (IRS) aided non-orthogonal multiple access (NOMA) system, where a base station (BS) serves multiple users with the aid of IRSs.

• Our goal is to maximize the sum rate of all users by jointly optimizing the active beamforming at the BS and the passive beamforming at the IRS, subject to successive interference cancellation decoding rate conditions and IRS reflecting elements constraints.
• In term of the characteristics of reflection amplitudes and phase shifts, we consider ideal and non-ideal IRS assumptions.
• To tackle the formulated non-convex problems, we propose efficient algorithms by invoking alternating optimization, which design the active beamforming and passive beamforming alternately.