## 4 System Perspective Compatibility Analysis
### Interference Assessment during the Take-Off and Landing Phases of an Aircraft
Since some routes in China lack ADS-B data information during the takeoff phase, the following analysis focuses on the aggregate interference data of EDDB-KIAD and KJFK-KLAX in Table 6.  
The following simulation of the aggregate interference suffered by the aircraft in different environments during landing is shown in Figure 14.  
The simulation results show that during the landing period, as the altitude of the aircraft decreases, the distance of the aircraft from the center point of the ground 5G base station's aggregate interference is gradually close to the center point of the ground 5G base station, and therefore, the aggregate interference suffered by the aircraft gradually increases. The relationship between the aggregate interference and the flight altitude and horizontal isolation distance for different flight paths in the two propagation environments is shown in Table 7 below. As can be seen from the data in Table 7, there is a slight difference in the total collective interference from ground-based 5G base stations for different flight paths. Similar to the takeoff phase of the airplane, the value of the total collec  
Figure 12: The 5G aggregate interference simulation during takeoff. Figure 13: Relationship between airplane altitude and 5G base station. RMa propagation environment is slightly smaller than that of the free-space propagation case. When landing close to the ground, ground-based 5G base stations can cause harmful interference to RDSS receivers. The aggregate interference data of the two routes EDDB-KIAD and KJFK-KLAX in different 5G propagation environments during the landing phase are analyzed as shown in the following Table 7.  
In summary, in practice, the focus should be on the process of the airplane taxiing, accelerating, and lifting from the ground to leaving the ground. The landing phase should focus on the process of the airplane descending from the air, approaching the landing area, decelerating, grounding, and taxiing to a stop. In these two stages, certain physical isolation measures should be taken in time to avoid affecting the normal operation of the RDSS receiver. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Dissemination Environment** & **Flight Altitude (m)** & **Horizontal Distance (m)** & **Aggregate Interference (dBm)** \\ \hline \multirow{3}{*}{EDDB-KIAD Free Space} & 75.31 & 50.8 & \(-\)121.85 \\  & 89.62 & 158 & \(-\)127.87 \\  & 103.93 & 251 & \(-\)131.39 \\ \hline \multirow{3}{*}{KJFK-KLAX Free Space} & 27.5 & 84.6 & \(-\)119.67 \\  & 47 & 171.6 & \(-\)125.69 \\  & 66.50 & 258.5 & \(-\)129.21 \\ \hline \multirow{3}{*}{EDDB-KIAD RMA} & 75.31 & 50.8 & \(-\)126.60 \\  & 89.62 & 158 & \(-\)141.03 \\  & 103.93 & 251 & \(-\)149.47 \\ \hline \multirow{3}{*}{KJFK-KLAX RMA} & 27.5 & 84.6 & \(-\)126.17 \\  & 47 & 171.6 & \(-\)140.60 \\ \cline{1-1}  & 66.50 & 258.5 & \(-\)149.04 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Summary analysis of interference data from EDDB-KIAD and KJFK-KLAX during the takeoff phase. Figure 14: The 5G aggregate interference simulation during landing.