# Distance Protection for Coexistence of 5G Base Station and Satellite Earth Station
## 4 Numerical Results
### Restriction Zone
#### 4.2.2 Restriction Zone and BS Tx Power Control for 4 \(\times\) 4 Antenna Array  
It is seen from Figures 24 and 25 that, although the exclusion zone is larger for the BSs than using the omnidirectional antenna, the restriction zone is much smaller, especially in the rear of the ES antenna. This is owed to the directional attenuation of the MIMO antenna array. The UMi has the largest restriction zone, although it has the smallest exclusion zone; furthermore, its required mean Tx power reduction is highest because it has the smallest ISD. * RMa, ISD = 1732 m, in 100 \(\times\) 100 km area: (1) About 3320 BSs can be deployed outside the exclusion zone in the RMa (2) The interference threshold for the restriction zone in the RMa is \(-\)47.39 dB  
Figure 23: Mean Tx power reduction for the BS versus the number of BSs. Figure 22: The size of the exclusion and restriction zones for different scenarios using omni antenna. The red lines show the exclusion zone (no BSs can be deployed) and the pink lines show the restriction zone (BSs can be deployed with Tx power control). The blue lines indicate that BSs can be deployed in these areas without restrictions. \begin{tabular}{l l} (3) & About 606 BSs within the restriction zone require Tx power control in the RMa \\ \(\bullet\) & UMa, ISD = 500 m, in 30 \(\times\) 30 km area: \\ (1) & About 3463 BSs can be deployed outside the exclusion zone in the UMa \\ (2) & The interference threshold for the restriction zone in the UMa is \(-\)47.59 dB \\ (3) & About 1450 BSs within the restriction zone require Tx power control in the UMa \\ \(\bullet\) & UMi, ISD = 200 m, in 30 \(\times\) 30 km area: \\ (1) & About 21,831 BSs can be deployed outside the exclusion zone in UMi \\ (2) & The interference threshold for the restriction zone in the UMi is \(-\)55.59 dB \\ (3) & About 10,960 BSs within the restriction zone require Tx power control in the UMi. \\ \end{tabular}   
Unlike the cases with the omnidirectional antennas, most of the BSs need to decrease their Tx power by 1 dB, not only in the RMa but also in the UMa and UMi. This is because the 4 \(\times\) 4 antenna has a higher gain than the omnidirectional antenna but has a similar mean power reduction value. This means that a lower power reduction is more efficient in the UMa and UMi using the 4 \(\times\) 4 antenna array. However, the UMi still requires the highest mean Tx power reduction. In Figures 26-31, we further compare the results using different antennas. 1. For the RMa scenario, the array antenna has a higher gain and larger exclusion zone. Although the exclusion zone is larger than that of the omnidirectional antenna, the rear restriction zone of the ES antenna is much smaller. This is because of the directional attenuation of the MIMO antenna array. The larger the number of elements in the array, the larger the exclusion zone. This also results in a larger restriction zone, owing to the higher gain of the antenna array, as shown in Figure 26.  
Figure 24: The size of the exclusion and restriction zones for different scenarios using 4 \(\times\) 4 antenna array. Figure 25: Mean Tx power reduction for the BS versus the number of BSs. The following results are seen from Figure 27 and Table 4:  
* Because of the larger exclusion zone, the number of BSs that can be deployed continues to decrease with the increasing number of array elements. * Comparing the omnidirectional antenna and 4 \(\times\) 4 antenna array, the number, and percentage of BSs that require Tx power control are significantly lower because of the drastic shrinkage of the restriction zone. However, owing to the higher antenna gain, the mean Tx power reduction is higher for the case of BSs with a 4 \(\times\) 4 antenna array. * By increasing the number of antenna elements, the number and percentage of BSs requiring Tx power control also increase, owing to the expanded restriction zone. * By increasing the number of antenna elements, the maximum Tx power and mean Tx power reduction increase, owing to the higher antenna gain.