On the SE and EE in Massive MIMO and NOMA

A comparative analysis on the Spectral Efficiency (SE) and Energy Efficiency (EE) in Downlink (DL) single-cell massive Multiple-Input Multiple-Output (mMIMO) and Non-Orthogonal Multiple Access (NOMA) considering a Base Station (BS) equipped with $M$ antennas, while $K$ devices operates with a single-antenna, and devices loading $\rho=\frac{K}{M}$ ranging in $0 < \rho\leq 2$ is carried out. In NOMA system, devices are overlapped in the power-domain; hence, NOMA is able to serve a greater number of devices. Under certain devices loading conditions, the NOMA overcame the mMIMO in terms of SE-EE trade-off, while continuing operate conveniently in the extended range $0.6 < \rho < 2.0$. We demonstrate that NOMA system is capable to operate suitably under higher system loading. The proposed analysis of the areas under SE and EE curves reveals that NOMA achieves highest area results.