Abstract: The 5G wireless system relies on Non-Orthogonal Multiple Access (NOMA) as a radio access scheme using extremely-dense base stations and unprecedented number of antennas to provide improved performance, high degree of integrative services, high-rate coverage and seamless user experience. The difference in the number of antennas used in the Mobile Devices (MDs) and those in the Base-Stations (BSs) in a cell plays a significant role in the overall system performance. Evaluation of the influence of such difference (δ) is analyzed in this study based on the outage probability, Pr_k^out. Computer simulation results are provided to facilitate the performance evaluation of the MIMO-NOMA and also, to demonstrate the accuracy of the developed analytical results. The achieved results reveal that a trade-off between the level of the SNR and the δ in the outage probability. Also, strategy of pairing users in a cluster plays an important role in the value of Pr_k^out when the number of users in a cluster is increased more than two users the performance is governed by allocation of the transmit power coefficient with level of SNR besides δ, compared with that of the conventional orthogonal Multiple Access (OMA).