Beamspace-MIMO-NOMA Enhanced mm-Wave Wireless Communications: Performance Optimization

In the literature, it is considered that the Multi-Input Multi-Output (MIMO) antennas are the most capable approach to meet all 5G requirements. One of the MIMO mm-wave drawbacks is the elevated power consumption due to Radio- Frequency-Chains (RF -Chains), which is efficiently solved using the beamspace-MIMO concept that reduces the total RF -chains number without significant performance loss. Another issue appeared with beamspace - MIMO, the limited number of users served on the exact time-frequency domain. To overcome these challenges, it has been proposed to use the Non-Orthogonal-Multiple-Access (NOMA) with beamspace to produce the new paradigm of beamspace-MIMO-NOMA. Hence, it can serve a group of users with correlated channels via the same beam using one RF -chain, which makes the users' number more than the RF -Chains number. This paper discusses the Spectral\Energy Efficiency (SE\EE) of the proposed scheme. Specifically, we propose and develop a low-complex iterative algorithm that reaches a near-perfect performance. The suggested approach, namely MSE-DP A, which stands for Mean-Square-Error Based Dynamic-Power-Allocation-Algorithm, is verified for the validity of this Figure-of-Merit. Simulation results show superior outcomes in terms of EE, which is about 85% greater than the traditional-MIMO systems.