Angle-Domain Hybrid Beamforming-Based mmWave Massive MIMO-NOMA Systems

The millimeter-wave (mmWave) large-scale antenna arrays (LSAAs) systems play a vital role in increasing the beamforming (BF) gain and acquiring highly directional propagation. Recently, non-orthogonal multiple access (NOMA) has been integrated into these to manage massive connectivity achieve spectral-efficient communications. This paper focuses on angle-domain (AD) hybrid for mmWave LSAAs NOMA systems, thanks low complexity, power consumption, channel estimation overhead. However, with limited radio-frequency chains, BF-based single-beam (SB)-NOMA scheme generating single beam serve users fails exploit multi-user diversity due narrow beams LSAAs. To tackle this limitation, we design schemes offering additional degrees of freedom. More importantly, they require only knowledge angular information are suitable either linear or rectangular arrays, unlike those proposed literature. first exploits time-domain resources schedule groups having high spatial interference within distinct time slots. minimize need fast precise synchronization when applying division (TDMA) NOMA, leverage multi-beam (MB)-NOMA framework. And propose joint SB-and MB-NOMA benefit from diversity, whatever cell load users’ positions. Using New York University simulator (NYUSIM), further validate performance compared solution literature others using fully digital BF. Specifically, TDMA-based achieves sum-rate up 83% over one existing Moreover, verify superiority both instead MB-NOMA.