Efficient three-dimensional deployment of multiple unmanned aerial vehicles supporting ground base station toward maximizing served users with heterogeneous quality-of-service requirements

Unmanned aerial vehicles (UAVs) are critical in wireless networks that can provide wireless broadcast and high-rate transmissions. UAVs can be used as flying base stations without an infrastructure to improve coverage, capacity, line-of-sight (LoS) connection, and rate performance in wireless communication. Furthermore, UAVs support terrestrial base stations in overload demand and disaster situations. Our presented method enables the ground base station (GBS) to collaborate with many UAVs while optimizing the number of served users and considering the influence of obstructing barriers on the air-to-ground (A2G) model. Our work investigates a model to find the efficient placements of multiple UAVs and optimize bandwidth between UAVs and GBS to enhance network performance by maximizing the number of served users with heterogeneous quality-of-service requirements. Three approaches have been employed to find the minimal number of UAVs that maximize the number of served users in the given area. The first is hybrid exhaustive search and K-means algorithms, the second is hybrid particle swarm optimization (PSO) and K-means algorithms, and the third is the greedy algorithm. The simulation results show that the maximum percentage of users served is equal to 100% using the exhaustive search algorithm. Furthermore, the percentage once using the PSO algorithm is 98% and 99.5% when deploying three and four UAVs, respectively.