Massive MIMO and NOMA bits-per-antenna efficiency under power allocation policies

A comparative resource allocation analysis in terms of received bits-per-antenna spectral efficiency (SE) and energy (EE) downlink (DL) single-cell massive multiple-input multiple-output (mMIMO) non-orthogonal multiple access (NOMA) systems considering a BS equipped with many (M) antennas, while K devices operate single-antenna, the loading ρ=KM ranging 0<ρ≤2 is carried out under three different (PA) strategies: inverse channel power (PICPA), modified water-filling (Δ-WF) method, equal (EPA) reference method. Since NOMA system, two per cluster are overlapped power-domain, matrix requires transformation to perform zero-forcing (ZF) precoding as adopted mMIMO. Hence, operating antennas can favor group higher array gain, overcoming mMIMO conveniently range 0.6<ρ<2.0. In such scenario, more realistic useful metric consists evaluating area SE EE curves, by measuring bit-per-antenna bit-per-antenna-per-watt efficiency, respectively. Our numerical results confirm superiority w.r.t. an order 3x for SE-area 2x EE-area metric.