# Distance Protection for Coexistence of 5G Base Station and Satellite Earth Station
## 5 Conclusions  
In this work, we propose a new distance isolation method to enable the coexistence of FSS ES and BSs. In the proposed distance protection method, the size of the exclusion zone is different for various scenarios (RMa > UMa > UMi), where higher elevation angles imply larger off-bioresight angles. This means that lower ES antenna gains toward the north side cause lower interferences on the north side in addition to a smaller exclusion zone. Compared to using an omnidirectional antenna, the use of an antenna array allows a larger exclusion zone at the north side of the ES. This is because the maximum gain of the antenna array is higher than that of the omnidirectional antenna. However, on the south side of the ES, the exclusion zone is much smaller because of the directional attenuation pattern of the antenna array. The exclusion zone can be enlarged by increasing the number of antenna elements. The UMi has the largest restriction zone, smallest exclusion zone, and the highest required mean Tx power reduction because of its small ISD value. In the UMa and UMi, the mean Tx power reductions are lower in cases where antenna arrays are used. This is because using the antenna array allows many of the cells to only reduce their Tx power by 1 dB. However, in the case of using an omnidirectional antenna, reducing the Tx power by 1 dB barely makes any difference, and most of the BSs need to further decrease their Tx power. Hence, the proposed power control scheme is more efficient in cases where the antenna array is used in the UMa and UMi. Additionally, the proposed scheme and conclusions may help the actual 5G network design and deployment when the issue of \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Antenna Type**} & **Total \# of BSs** & **Interference** & **Number of BSs in** & **\% of Deployed** & **Mean Tx Power** \\  & **That Can Be** & **Threshold for** & **the Restriction** & **BSs That Require** & **Reduction in the** \\  & **Deployed** & **Restriction Zone** & **Zone** & **Tx Power Control** & **Restriction Zone** \\ \hline Omni & 22,061 & \(-\)55,63 dB & 22,061 & 100 & 27.05 dB \\ \(4\times 4\) Array & 21,831 & \(-\)55.59 dB & 10,960 & 50.20 & 26.79 dB \\ \(8\times 8\) Array & 21,193 & \(-\)55.46 dB & 12,218 & 57.65 & 27.78 dB \\ \(16\times 16\) Array & 20,855 & \(-\)55.39 dB & 13,010 & 62.38 & 28.35 dB \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Mean Tx power reduction in the restriction zone and BS Tx power control in UMi. Figure 31: Tx power control chart in UMi scenario. coexistence between 5G system and satellite system should be solved. Firstly, the exclusion zone and restriction zone can be achieved by loading the actual parameters of ES and 5G BSs. In this way, it is clear where no BSs can exist and where BSs may can be deployed. Next, with the proposed power control scheme, the maximum Tx power of each BSs in the restriction zone can be achieved either by using the 3 GPP network layout or customized BSs site selection. For the future, we will focus on developing angular protection measures to mitigate the interfering beams, decrease the sizes of the exclusion and restriction zones, and decrease the BS Tx power reduction within the restriction zone. Additionally, hybrid technologies can be considered for the future generation system, such as 6G, since non-terrestrial network will become a part of it. [PERSON] and [PERSON] contributed to the main idea of this research work. [PERSON] wrote computation codes, performed the simulations, experiments, and database collection. [PERSON] and [PERSON] confirmed numerical results of the work. The research activity was planned and executed under the supervision of [PERSON], [PERSON], [PERSON] and [PERSON] contributed to the writing of this article. All authors have read and agreed to the published version of the manuscript. This work was supported by Electronics and Telecommunications Research Institute (ETRI) grant funded by the Korean government (6011-2018-00016, A study on the supply of 5G additional frequency).