## 4 Numerical Results and Discussion  
To investigate the system performance of the massive MIMO-NOMA network model shown in Figure 1, we propose parameters for both a theoretical analysis and the Monte Carlo simulations, as shown in Table 1.  
Let a wireless network contain coupled relays and three devices (\(N=3\)). The coupled relays are allocated nearby. The distances from the BS to the coupled relays are \(d_{R_{1}}=d_{R_{2}}=10\) m, and the distances from the coupled relays to devices \(D_{1}\), \(D_{2}\) and \(D_{3}\) are \(d_{1}=v_{1}=5\) m, \(d_{2}=v_{2}=7\) m and \(d_{3}=v_{3}=10\) m, respectively. The path-loss exponent refers to an indoor environment with \(\lambda=4\). By modeling the more challenging indoor environment, the performance bound of the less challenging outdoor scenario is therefore also covered. In 4G Long-Term Evolution (LTE) release 8, the maximum numbers of antennas at the BS and user equipment are 4T4R and 1T2R, respectively. In 4G LTE-Advanced (LTE-A), the number of antennas is greater to allow the use of 8T8R at BSs and 2T2R at devices in LTE-A schemes. Therefore, massive MIMO networks need at least an 8T8R antenna array at the BS. However, the present study assumes a certain number of antennas equipped at the BS (\(A_{0}=4\)), coupled relays \(R_{1}\) (\(A_{1}=4\)), \(R_{2}\) (\(A_{1}=16\)), and devices (\(A_{2}=2\)) to prove the the benefits of massive MIMO (even transmission block) over MIMO (odd transmission block). The fading channel from the transmitting antennas at the BS to the receiving antennas at the coupled relays are distributed over Rayleigh fading channels. Based on distances and the path-loss exponent, the expected channel gains from the BS to coupled relays are \(\sigma_{R_{1}}^{2}=\sigma_{R_{2}}^{2}=1\times 10^{-4}\) and from the coupled relays to devices \(D_{1}\), \(D_{2}\), and \(D_{3}\) are \(\sigma_{1}^{2}=16\times 10^{-4}\), \(\sigma_{2}^{2}=4.1649\times 10^{-4}\), and \(\sigma_{3}^{2}=1\times 10^{-4}\). Each fading channel randomly generates \(1e6\) experiments. To simplify, the devices require the same bit-rate thresholds \(R_{1}^{*}=R_{2}^{*}=R_{3}^{*}=0.1 bps/Hz\) and SNR \(\rho_{S}=\rho_{R}=\{0,\ldots,30\}\) dB. By applying (7), the PA factors for devices \(D_{1}\), \(D_{2}\), and \(D_{3}\) are \(\alpha_{1}=0.1667\), \(\alpha_{2}=0.3333\), and \(\alpha_{3}=0.5\), respectively. The present study assumes that coupled relays may fully collect EH (\(\eta=1\)). The PS factor in an odd transmission block is \(\lambda=0.4\). Therefore, \(0.4P_{S}\) and \(0.6P_{S}\) are applied to EH and DT processing, respectively, whereas the PS factor in an even transmission block is reduced (\(\lambda=0.4\)) since the relay \(R_{2}\) in this block is equipped with a greater number of antennas than relay \(R_{1}\) in an odd transmission block. Figure 3 plots the OP performance at relay \(R_{1}\) and devices in odd transmission blocks. Note the various markers and line plot analysis (Ana) and simulation (Sim) results. The analysis results of OP performance at relay \(R_{1}\) are given by (30) or (34) and for devices \(D_{n}\) by (36) or (38). The analysis results were verified with Monte Carlo simulations for relay \(R_{1}\) given by (31) or (35) and for devices by (37) or (39), where \(\mathcal{R}=R_{1}\) and \(\theta=odd\). Figure 3 illustrates that device \(D_{3}\) achieved the best OP results, even though device \(D_{3}\) was the farthest device and therefore allocated the biggest PA factor \(\alpha_{3}=0.5\). When SRN \(\rho\rightarrow\infty\), the OP results of relay \(R_{1}\) and devices tend toward zero. Figure 4 plots the OP performance at relay \(R_{2}\) and devices in even transmission blocks. To improve the networking capacity and energy, we equipped a large number of antennas at relay \(R_{2}\) and increased the PS factor \(\lambda=0.6\). By increasing the PS factor, relay \(R_{1}\) was able to harvest more energy but relay \(R_{2}\) could receive weak signals.