Double Phase Shifter-Based Hybrid Beamforming and User Scheduling for Coexistence of Near-Field and Far-Field mmWave NOMA Systems

This paper proposes a double phase shifter–based hybrid beamforming (DPS-HBF) framework for millimeter-wave NOMA systems, enabling the simultaneous realization of beam steering and beam focusing within a unified analog architecture. By superposing two independent phase-shifter vectors per beam, DPS-HBF flexibly supports heterogeneous near-field and far-field users without requiring full channel state information. To exploit this capability, a hierarchical scheduling framework combining Bitmask Dynamic Programming, Maximum Weight Matching, andk-best Semi-Greedy User Scheduling is developed to balance optimality, scalability, and computational complexity. The proposed design relies solely on low-overhead SINR feedback, making it suitable for practical large-scale deployments. Simulation results show that DPS-HBF consistently outperforms existing hybrid beamforming and orthogonal multiple access baselines in terms of sum-rate and fairness, achieving up to 30–35% throughput gains over the strongest benchmark under moderate-to-high SNR conditions.