Power Minimizing Beamforming and Power Allocation for MISO-NOMA Systems

This correspondence paper considers a multiple-input single-output non-orthogonal multiple access (MISO-NOMA) system that spatially multiplexes NOMA signals formed by superimposing two user symbols in the power domain. We aim to design practical beamforming (BF), power allocation (PA), and user clustering methods for the system by minimizing the transmit power under the rate constraints. The two-step BF and conditionally optimal PA are devised in closed-form expressions that facilitate user clustering based on message passing and effective channel correlation. The results show that the MISO-NOMA system with the proposed BF, PA, and user clustering methods outperforms the benchmark systems of comparable complexity.