# Deployment Protection for Interference of 5G Base Stations with Aeronautical Radio Altimeters
## 4 Results and Discussion
### Prohibited Zone with Omnidirectional Antenna
#### 4.1.1 Horizontal Prohibited Zone  
Figure 12a-c illustrate the 3D representations when the aircraft's altitude AGL is 200 ft (60.96 m) for RMa, UMa, and UMi scenarios, respectively. The three-dimensional coordinate system showcases the \(X\)-axis, representing the base station's \(X\)-coordinate on the horizontal plane, and the \(Y\)-axis, representing the base station's \(Y\)-coordinate on the horizontal plane. The \(Z\)-axis indicates the level of interference detected at the aircraft's position, depicted through color differentiation.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & **RMa** & **UMa** & **UMi** \\ \hline BS maximum Tx power (dBm) & 46 & 38 & 38 \\ BS antenna height (m) & 35 & 25 & 10 \\ Antenna pattern & & 3 GPP TR 38.901 & \\ Omni antenna gain (dBi) & & 15 & \\ Maximum array gain 16 \(\times\) 16 (dBi) & & 29.5 & \\ Channel bandwidth (MHz) & 100 & 100 & 100 \\ BS maximum PSD (dBm/MHz) & 26 & 18 & 18 \\ Building height (m) & 7 & None & None \\ Street width (m) & 25 & None & None \\ LOS shadow fading (dB) & 6 & 4 & 4 \\ NLOS shadow fading (dB) & 8 & 6 & 7.82 \\ Maximum vertical scan angle \(\theta\) (\({}^{\circ}\)) & 10 & 10 & 10 \\ \hline \hline \end{tabular}
\end{table}
Table 3: BS parameters.  
Figure 12: Horizontal Prohibited zones of RMa, UMa, and UMi at \(AGL=200\) ft, 1000 ft, 2000 ft (omni-directional antenna). (**a**) RMa (\(AGL=200\) ft, 3D). (**b**) UMa (\(AGL=200\) ft, 3D). (**c**) UMi (\(AGL=200\) ft, 3D). (**d**) RMa (\(AGL=200\) ft). (**e**) UMa (\(AGL=200\) ft). (**f**) UMi (\(AGL=200\) ft). (**g**) RMa (\(AGL=1000\) ft). (**h**) UMa (\(AGL=1000\) ft). (**i**) UMi (\(AGL=1000\) ft). (**j**) RMa (\(AGL=2000\) ft). (**k**) UMa (\(AGL=2000\) ft). (**l**) UMi (\(AGL=2000\) ft).  
To elaborate further on the concept of the prohibited zone, 2D representations of 200 ft for RMa, UMa, and UMi scenarios are also provided in Figure 12d-f. The results are calculated within \(\pm 1\) km. The regular and irregular red circles in the figures are prohibited zones. Base stations exceeding the interference threshold are distributed within the zone enclosed by the red line. Outside the red line, the interference power attenuates due to increased distance, falling below the interference threshold. Two-dimensional representations of 1000 ft (304.8 m) are provided in Figure 12g-i, and representations of 2000 ft (609.6 m) are provided in Figure 12j-l. The results are calculated within \(\pm 5\) km.
* Among the three types of base station, the prohibited zone of the RMa base station is the largest. This is primarily because the RMa base station has the highest transmission power and height.
* For the same type of base station, the prohibited zone is largest when \(AGL=2000\) ft and smallest when \(AGL=200\) ft. This is the result of the dynamic variation of both interference threshold and path loss.
* The magenta line represents the prohibited zone without considering the 6 dB margin. The ICAO 6 dB margin increases the prohibited zone radius by 0.2-0.9 km.
* The irregularity of the prohibited zones in Figure 12f is primarily attributed to the statistical feature of line-of-sight (LOS) and non-line-of-sight (NLOS) path loss, assuming that the occurrence probabilities of both LOS and NLOS are equal to 50%. In UMi scenario, there is a significant difference in the attenuation between LOS and NLOS due to the fact that the UMi base station has a height of 10 m, which is the lowest among the three types of base stations. This results in a greater difference in attenuation between NLOS and LOS. In Figure 12i,J, with \(AGL=1000\) ft, 2000 ft, the aircraft is at a higher altitude. The path loss is nearly identical between the LOS and NLOS scenarios, and the statistical feature of path loss is not pronounced. As a result, the prohibited zone does not exhibit irregularity.