## 4 System Perspective Compatibility Analysis
### The 5G Interference with BeiDou RDSS Receiver Analysis Results  
This section focuses on the analysis of the distance isolation required for different frequency isolation between the 5G system and the RDSS system, which is mainly summarized by dividing the 5G system into the 5G base station and the 5G terminal interfering with the RDSS receiver. According to the relationship between ACLR and system frequency isolation in the first two columns of Table 4, the required distance isolation for different frequency isolation can be calculated as shown in the last column of Table 4.  
From the data in Table 4, it can be seen that different degrees of 5G out-of-band leakage will result in different frequency isolation than that of the RDSS system, and the smaller the frequency isolation, the more severe the out-of-band leakage of 5G, and the greater the distance isolation required. When the frequency isolation is greater than 10 MHz, the value of ACLR will no longer change. To summarize, the distance isolation required for the 5G base station to interfere with the RDSS receiver is between 0.154 km and 4.26 km. Similar to the analysis of the 5G base station interfering with the BeiDou RDSS receiver, according to the out-of-band emission template of the 5G terminal specified in the standard 3 GPP TR36.101 [22] and the Equation (14), the relationship between the ACLR and the frequency isolation when neighboring frequency coexistence can be obtained, the limit of out-of-band spurious radiation of the terminal will no longer change when the frequency isolation of the two systems is more than 25 MHz. Therefore, the ACLR value will also no longer change. The analysis results of the 5G terminal interfering with the RDSS receiver are shown in Table 5. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{\begin{tabular}{c} **Frequency** \\ **Isolation** \\ **(MHz)** \\ \end{tabular} } & \multicolumn{2}{c}{**5G Base**} & \multicolumn{2}{c}{**5G Base**} & \multicolumn{2}{c}{**BeiDou**} & \multicolumn{2}{c}{**Interference**} & \multicolumn{2}{c}{**Allowable**} & \multirow{2}{*}{\begin{tabular}{c} **Required** \\ **Distance** \\ **Isolation** \\ **Isolation** \\ **(km)** \\ \end{tabular} } \\  & **ACLR (dB)** & \begin{tabular}{c} **Station** \\ **Station** \\ **Transmit** \\ **(dBm)** \\ \end{tabular} & \begin{tabular}{c} **5G Base** \\ **Station** \\ **Antenna** \\ **Gain (dBi)** \\ \end{tabular} & \begin{tabular}{c} **BeiDou** \\ **Terninal** \\ **Antenna** \\ **Gain (dBi)** \\ \end{tabular} & \begin{tabular}{c} **Interference** \\ **Received** \\ **Themimals** \\ **(dBm)** \\ \end{tabular} & \
\begin{tabular}{c} **Allowable** \\ **Maximum** \\ **Interference Power** \\ **(dBm)** \\ \end{tabular} &
\begin{tabular}{c} **Required** \\ **Path Loss** \\ **(dB)** \\ \end{tabular} \\ \hline
0 & 30.07 & 38 & 18 & 0 & 22.93 & \(-\)127 & 152.93 & 4.2693 \\ \hline
1 & 31.09 & 38 & 18 & 0 & 21.91 & \(-\)127 & 151.91 & 3.8019 \\ \hline
2 & 31.98 & 38 & 18 & 0 & 21.02 & \(-\)127 & 151.02 & 3.3884 \\ \hline
3 & 33.07 & 38 & 18 & 0 & 19.93 & \(-\)127 & 149.93 & 3.0199 \\ \hline
4 & 34.09 & 38 & 18 & 0 & 18.91 & \(-\)127 & 148.91 & 2.6915 \\ \hline
5 & 35.00 & 38 & 18 & 0 & 18.00 & \(-\)127 & 148.00 & 2.3988 \\ \hline
6 & 35.97 & 38 & 18 & 0 & 17.03 & \(-\)127 & 147.03 & 2.1379 \\ \hline
7 & 37.21 & 38 & 18 & 0 & 15.79 & \(-\)127 & 145.79 & 1.8620 \\ \hline
8 & 38.96 & 38 & 18 & 0 & 14.04 & \(-\)127 & 144.04 & 1.5135 \\ \hline
9 & 41.92 & 38 & 18 & 0 & 11.08 & \(-\)127 & 141.08 & 1.0715 \\ \hline
10 & 58.88 & 38 & 18 & 0 & \(-\)5.88 & \(-\)127 & 124.12 & 0.1548 \\ \hline
11 & 58.88 & 38 & 18 & 0 & \(-\)5.88 & \(-\)127 & 124.12 & 0.1548 \\ \hline
12 & 58.88 & 38 & 18 & 0 & \(-\)5.88 & \(-\)127 & 124.12 & 0.1548 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Deterministic analysis results of 5G base station interference to RDSS receivers. \begin{table} \begin{tabular}{c} **Required** \\ **Distance** \\ **Isolation** \\ **(km)** \\ \end{tabular}