Energy-Efficient Power Allocation in Millimeter Wave Massive MIMO With Non-Orthogonal Multiple Access

In this letter, we investigate the energy efficiency (EE) problem in a millimeter wave massive MIMO system with non-orthogonal multiple access (NOMA). Multiple two-user clusters are formulated according to their channel correlation and gain difference. Following this, we propose a hybrid analog/digital precoding scheme for the low radio frequency chains structure at the base station. On this basis, we formulate a power allocation problem aiming to maximize the EE under users' quality of service requirements and per-cluster power constraint. An iterative algorithm is proposed to obtain the optimal power allocation. Simulation results show that the proposed NOMA scheme achieves superior EE performance than conventional OMA scheme.