# Modeling of NOMA-MIMO-Based Power Domain for 5G Network under Selective Rayleigh Fading Channels
## 5 Results and Discussions  
### The Outcomes of the DL Scenario  
The DL NOMA system results showed that using 64 \(\times\) 64 MIMO improved the SE and BER performance. The near-far user's problem is also resolved, where the performance of all users becomes close to each other's for different power location coefficients, transmitted power, and distance parameters when compared without MIMO DL NOMA performance. Figure 3 depicts the DL NOMA BER performance versus transmitted power at 80 MHz BW. The findings indicate that the BER performance decreases as transmitted power increases. As an outcome, the _U4_ BER performance is best for all users, because _U4_ is the nearest one. At a transmitter power of 25 dBm, the BER rate for _U1_, _U2_, _U3_, and _U4_ is found to be 20%, 28%, 22%, and 8%, respectively. Figure 4 shows the DL NOMA BER performance against transmitted power at 200 MHz BW; the findings show that the BER performance decreases as transmitted power increases. As a result, the U4 BER performance is best when compared with all users because _U4_ is the nearest one. At a transmit power of 25 dBm, the BER rates for _U1_, _U2_, _U3_, and _U4_ are found to be 27%, 36%, 31%, and 13%, respectively. The 64 \(\times\) 64 MIMO DL NOMA enhances the performance of BER for the best user U4 from \(10^{-1.7}\) to \(10^{-5.2}\) at 80 MHz then, from \(10^{-1.5}\) to \(10^{-5}\) at 200 MHz BW at a transmitter power of 40 dBm in Figure 4. In contrast, the SE performance for the best user _U4_ is improved by 8 \(\times\) 10\({}^{-3}\) bps/Hz for 80 MHz BW and by \(10^{-2}\) bps/Hz for 200 MHz BW at a transmitter power of 40 dBm. The UL NOMA systems results obtained using 64 \(\times\) 64 MIMO enhanced the average capacity rate performance by 12 bps/Hz, reduced the OP by 15 \(\times\) 10\({}^{-3}\) for 80 MHz BW at SNR of 1 dB. \begin{table}
\begin{tabular}{c c c} \hline \hline
**No.** & **Parameters** & **Values** \\ \hline
1. & Number of users & 4 users \\
2. & Transmit power & \(-\)30 to 30 dBm \\
3. & Bandwidth & BW1 & 80 MHz \\  & & User1 & 800 m \\  & & User 2 & 600 m \\
4. & Distances & User 3 & 300 m \\  & & User 4 & 100 m \\
6. & Path loss exponent & 4 \\
7. & MIMO & 64 \(\times\) 64 & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Simulator parameters for the UL scenario. Figure 3: BER vs. transmit power for four users with varying distances and power coefficients, for DL NOMA at BW (80 MHz). At 80 MHz BW and 64 \(\times\) 64 MIMO, Figure 5 shows the DL NOMA BER performance versus transmitted power. When transmitted power is 20 dBm, the BER rate for U1, U2, U3, and U4 is found to be 19 \(\times\) 10\({}^{-4}\), 18 \(\times\) 10\({}^{-4}\), 8 \(\times\) 10\({}^{-4}\), and 5 \(\times\) 10\({}^{-4}\), respectively. Figure 6 shows the DL NOMA BER performance against transmitted power at 200 MHz BW and 64 \(\times\) 64 MIMO, at a transmitted power of 25 dBm, the BER rates for U1, U2, U3, and U4 are found to be 46 \(\times\) 10\({}^{-4}\), 43 \(\times\) 10\({}^{-4}\), 19 \(\times\) 10\({}^{-4}\), and 7 \(\times\) 10\({}^{-4}\), respectively. The MIMO system reduces the BER performance. Figure 4: BER against transmitting power for four users with varying distances and power coefficients, for DL NOMA at BW (200 MHz). Figure 5: BER vs. transmitting power for four users with varying distances and power coefficients, for DL NOMA at BW (80 MHz with 64 \(\times\) 64 MIMO for DL NOMA. Figure 7 shows the performance of the DL NOMA SE vs. transmitted power at 80 MHz BW, with the outcomes demonstrating that SE performance improves as transmitted power increases. As an outcome, the U4 BER performance is best for all users, because U4 is the nearest one. There is a clear separation of SE performance for all users from one another until the transmitted power reaches 5 dBm. Figure 8 depicts the DL NOMA SE performance versus transmitted power at 200 MHz BW, with the results indicating that increasing transmitted power improves SE performance. The U4 SE performance is best when compared with all users because U4 is the nearest one.