Reconfigurable Intelligent Surfaces Aided mmWave NOMA: Joint Power Allocation, Phase Shifts, and Hybrid Beamforming Optimization

In this paper, a reconfigurable intelligent surface (RIS)-aided millimeter wave (mmWave) non-orthogonal multiple access (NOMA) system is analyzed. particular, we consider an RIS-aided mmWave-NOMA downlink with hybrid beamforming structure. To maximize the achievable sum-rate under minimum rate constraint for users and maximum transmit power constraint, joint RIS phase shifts, beamforming, allocation problem formulated. solve non-convex optimization problem, develop alternating (AO) algorithm. Specifically, first, transformed into three subproblems, i.e., allocation, shifts analog optimization, digital design. Then, by keeping fixed of beamforming. Finally, given matrix, manifold (AMO)-based method successive convex approximation (SCA)-based are utilized to design respectively. Numerical results reveal that proposed AO algorithm outperforms existing schemes in terms sum-rate. Moreover, compared conventional without RIS, capable improving