## 4 Numerical Results and Discussion
\begin{table}
\begin{tabular}{c c} \hline \hline
**Parameters** & **Values** \\ \hline h\({}_{\rm{BN}}\) & 25 m \\ h\({}_{\rm{RN}}\) & 19.5 m \\ d\({}_{\rm{BL}}^{1}\) & 67 m \\ d\({}_{\rm{BL}}^{2}\) & 67.3 m \\ d\({}_{\rm{AL}}^{1}\) & 6.88 m \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Distance of the simulation scenario. On the other hand, the NR-D&F strategy with MIMO, have generated an improved behavior. In this sense, it can be seen that the (2 \(\times\) 2 \(\times\) 2) NR-D&F strategy with LS channel estimation acquired a BER performance of 9.9\(\times 10^{-3}\) at around \(\text{SNR}=16\) dB, implying that 8 dB and 4 dB performance gain was successfully reached, in comparison with SISO NR-D&F and (2 \(\times\) 2 \(\times\) 2) NR-A&F strategies, respectively. Nevertheless, (4 \(\times\) 4 \(\times\) 2) NR-A&F strategy overcome the performance of the (2 \(\times\) 2 \(\times\) 2) NR-D&F protocol with PCE  
Figure 11: BER vs. SNR of the cooperative system; 256-QAM signal. Figure 10: Bit Error Rate (BER) vs. Signal-to-Noise Ratio (SNR) of the cooperative system; 64-QAM signal. in approximately 2.5 dB. Besides, it can be noticed, from Figure 10, that the (4 \(\times\) 4 \(\times\) 2) NR-D&F protocol with knowledge of the channel generally achieved a better BER level of the proposed algorithms, more specifically, obtained the same performance as the (4 \(\times\) 4 \(\times\) 2) NR-D&F with LS channel estimation at SNR \(=\) 19.2 dB, such that an 0.8 dB performance gain was attained and overcoming the (4 \(\times\) 4 \(\times\) 2) NR-A&F strategy from SNR \(=\) 15.5 dB. We also have performed other curves for comparison of the mmWave MIMO cooperative system with the proposed schemes, which were presented from Figure 11; in this case, the 256-QAM constellation was considered. From reported BER in Figure 11, we can be observed that the developed relaying strategies present the same behavior. Nevertheless, it should be noticed that BER performance of the 64-QAM is better than 256-QAM, which was achieved due to the robustness that presents the 64-QAM front to 256-QAM. For example, it can be verified that the (4 \(\times\) 4 \(\times\) 2) NR-D&F strategy with 64-QAM scheme achieved reaching the same BER performance of the (4 \(\times\) 4 \(\times\) 2) NR-D&F protocol with 256-QAM constellation at around SNR \(=\) 15.8 dB, which supposes a performance gain of 4.2 dB. To evaluate the behavior of the implemented architectures, another KPI was considered. The output throughput of the processing of the New Radio DL-SCH transport channel was measured. The achievable throughput recorded for SISO and MIMO cooperative system for various mmWave NR-RN protocols are shown in Figures 12 and 13, for the 64-QAM and 256-QAM constellations, respectively. It can be observed, from the figures that the SISO D&F with LS technique achieved higher average throughput than the SISO A&F strategy. However, it may also be seen that, when the SISO NR-D&F with PCE scheme is introduced, the achievable capacity of the system is improved in comparison with the architectures mentioned above. More particularly, in the 64-QAM case for mmWave NR-D&F without channel knowledge, from Figure 12, indicates that the throughput at SNR \(=\) 20 dB was approximately 89.03 Mbps; nevertheless, with channel knowledge, a throughput of 91.83 Mbps could be reached with the same SNR value, such that a performance gain of about 17.00 Mbps and 19.80 Mbps, respectively, in comparison with 72.03 Mbps achieved by SISO A&F architecture. On the other hand, when compared with mmWave (2 \(\times\) 2 \(\times\) 2) NR-RN strategies, the achieved capacity is much higher than the SISO NR-RN protocols, as can be seen in Figure 12 and 13. In this context, the maximum performance of the SISO mmWave cooperative system was reached by the mmWave (2 \(\times\) 2 \(\times\) 2) MIMO NR-A&F at SNR \(=\) 19 dB, which has introduced an improved the system performance of around 2.1 Mbps, for 64-QAM constellation.