User Clustering and Optimized Power Allocation for D2D Communications at mmWave Underlaying MIMO-NOMA Cellular Networks

Fifth-generation (5G) cellular networks are being developed to meet the ever-growing data traffic across mobile devices and their applications. The core of 5G is leveraging wider higher frequencies available at millimeter wave frequency (mmWave) bands, thus providing very high rates for devices. Multi-input multi-output (MIMO) an essential technology overcoming propagation loss mmWave communications. In non-orthogonal multiple access (NOMA), user equipments (CUEs) communicate over same time-frequency resources using a multiplexed power domain. device-to-device (D2D) communications, two D2D (DUEs) without passing through base station. underlaying scenario, DUEs reuse allocated CUEs spectrum utilization but cause interferences Integrating communications with other technologies has great potential spectral efficiency improvement. Unfortunately, interference management resource allocation becoming increasingly challenging due aggressive reuse. this paper, MIMO-NOMA network system model developed. Consequently, novel proposed. A optimization problem formulated maximization. To solve NP-hard problem, decomposed into three subproblems: interference-aware graph-based clustering, beamforming design, optimized based on particle swarm optimization. Simulation results demonstrate that proposed algorithm delivers greater compared conventional operate underlay MIMO-orthogonal networks.