On the Performance Analysis of mmWave MIMO-NOMA Transmission Scheme

In this paper, we propose an optimal random beamforming technique in mmWave MIMO-NOMA transmission systems. In our model, we consider a NOMA system with a user pairing scheme that works based on the distance between the cellular base station (BS) and the active mobile users. The aim of this is to reduce the system overall overhead for massive connectivity and achieve the desired Quality of Service (QoS). We present an optimization problem with the aims to find the optimal random beamforming coefficients by minimizing the outage probability. We analyze the convexity of the outage probability for three user pairing schemes and prove that the proposed optimal random beamforming is convex in high signal-to-noise ratio (SNR). We utilize the gradient-based algorithm namely the gradient descent algorithm to find optimal random beamforming coefficients. Our simulation results demonstrate that the proposed transmission schemes reduce the outage probability and improve network performance compared to previous works.