Max-Min Fairness of mm-Wave Communication Using Multi-Beam Beamspace MIMO-NOMA

In order to increase the number of connections, a non-orthogonal multiple access (NOMA) scheme is taken into consideration in this study for mmwave multi-beam transmissions across beamspace (BS-MIMO) channels. We examine the maximized-minimal(max-min) rate of the beamspace MIMO-NOMA (BS-MIMO-NOMA) system according to power allocation in order to increase the throughput while retaining fairness of user. The difficulty is that non-convexity in the power allocation issue due to both inter-beam and intra-beam interference and takes a tough task to solve. To solve this problem, we address an iterative algorithm to figure out maximum-minimum rate and associated power allocation. We maximize and analyse the minimal rate of the BS-MIMO-NOMA in a conventional mmWave channel model to ensure the achievable sumrate of the proposed beamspace scheme. We show that when all users are given the same rate, the improved max-min rate (MMR) is achieved. For achieving the dynamic power allocation, a closed-form solution is developed by taking the Karush-Kuhn-Tucker (KKT) criteria into consideration. The proposed BS-MIMO-NOMA performs better than the existing orthogonal multiple access (OMA) techniques in terms of minimal rate, based on outcomes of the simulation.