## 4 Results and Discussion  
The path loss and received power are influenced by a wide range of variables since each model is unique in its design and features depending on the kind of operating environment it is used in. In this paper, PL and RP are estimated for urban and rural environments, respectively. The simulation results of the UMi, UMa, and RMa environments for mmWave frequencies are presented and analyzed in this section. PL and RP are estimated using the various path-loss models proposed by the standard organizational bodies. Figures 1-9 compare the PL of UMi, UMa, and RMa environments using various models at underutilized mmWave frequency bands of 28 GHz, 38 GHz, 60 GHz and 75 GHz, respectively. It has been found that the measured PL is affected by the distance (R), carrier frequency (f), and height of the BS antenna (\(h_{1}\)). than 3 GPP-SC for distances greater than 150 m. Consequently, 5 GCM-OS exhibits the lowest path loss beyond 150 m, while 3 GPP-SC yields the lowest path loss up to that point. The mmMAGIC-SC model generates the highest path loss in the NLOS scenario. It can be seen from Figures 1-4 that each model's path loss gradually rises with distance and frequency. The 5 GCM-OS model exhibits the lowest path loss in both LOS and NLOS scenarios for mmWave frequencies at various distances when compared to other models. Among them, the 3 GPP-SC and mmMAGIC-SC models yield the highest path loss in LOS and NLOS scenarios, respectively. In practical applications, network providers seek higher signal power and lower path loss. In the UMi scenario, the 5 GCM model produces the least path loss in LOS and NLOS scenarios at variable frequencies and distances. Therefore, the 5 GCM model is considered to be an optimal path-loss model,  
Figure 4: Path loss of an Urban Micro environment at 75 GHz. Figure 5: Path loss of an Urban Macro environment at 28 GHz. Figure 3: Path loss of an Urban Micro environment at 60 GHz. Figures 5-8 measure and compare the PL of the urban macro environment at 28 GHz, 38 GHz, 60 GHz, and 75 GHz, respectively. Compared to other models, the line-of-sight 5 GCM model produces less path loss, which can be observed in Figures 5-8. The line-of-sight 3 GPP path loss curve closely resembles the path loss in the LOS 5 GCM model. In LOS propagation, the path loss of 5 GCM is slightly higher than the path loss of 3 GPP model if the distance is less than 300 m, it is equal at a distance of 300 m, and if the distance is greater than 300 m, the path loss of 3 GPP is higher than the path loss of 5 GCM. Therefore, 5 GCM creates the lowest path loss after 300 m while 3 GPP generates the lowest path loss up to that point. The highest path loss is produced by the 5 GCM model in the NLOS scenario. It can be seen from Figures 5-8 that each model's path loss gradually rises with distance and frequency. In comparison to the other models, the 5 GCM and 3 GPP model generates the lowest path loss in LOS and NLOS scenarios, respectively, and these two models are assumed as optimal path-loss models and the optimal distance is 300 m in urban macro scenarios. The detailed PL values at various frequencies are listed in Table 6.  
Figure 9 measure and compare the PL of the rural macro environment at 28 GHz, 38 GHz, 60 GHz, and 75 GHz. It can be seen from Figure 9 and Table 4 that path loss gradually rises with distance and frequency. Path loss in urban micro cells and urban and rural macro cells can be affected by various factors such as distance, obstacles, interference, base station antenna height, and frequency band. Observations from Figures 1-9 are that the PL in urban micro cells is generally higher than in urban macro and rural macro cells due to the lower base station antenna height. The base station antenna height in urban and rural macro cells is generally higher than that of an urban micro cell due to the difference in their coverage areas and signal propagation characteristics.