Table 4 Performance optimization algorithm based on k-means++ and antenna adjusting

Input: Number of UAVs and user location coordinates.

Output: Antenna horizontal pointing and downtilt angle of UAV.

1. The number and position of UAV are computed by the k-means++ algorithm.

2. Calculate the distance of all users to the antenna lobe of the UAV, and the average distance can be calculated.

3. Update the antenna lobe pointing with 5° as the step size.

4. Repeat step 2, the new average distance can be calculated.

5. If the new average distance is less than average distance, the average distance is replaced by the new average distance.

6. Repeat steps 3 to 5, until all the conditions are calculated, and the smallest average distance is obtained. Then, the antenna lobe pointing is obtained at the same time.

7. Select the longest distance between the UAV and users

8. Calculate the optimal downtilt angle by formula (11).

9. Adjust the antenna lobe pointing and downtilt angle.

10. End.