| （英） |
Unmanned aerial vehicles (UAVs) equipped with cellular base stations, known as aerial base stations (ABSs), have been attracting attention as a key technology in Beyond 5G (6G), as they can provide communication environments to ground users more rapidly and flexibly compared to ground base stations. ABSs face many challenges in their practical application, especially, the limitation of the battery capacity of UAVs, which makes it difficult to provide a continuous communication environment for a long period. For this problem, replacement control has recently been proposed to realize continuous communication by exchanging the positions of a low-battery UAV and a fully-charged UAV while providing a communication environment to ground users. However, existing studies assume a single ABS scenario and do not consider the problem of inter-cell interference that arises in a multi-UAV environment. In this study, we propose a trajectory optimization method for replacement control in a multiple ABS network taking into account inter-cell interference. We consider a scenario in which a UAV with a low battery and a fully charged UAV waiting at a charging station exchange their positions. We assume that a user is in an outage if the signal-to-interference-plus-noise-ratio is below a threshold and formulate the trajectory optimization problem as the minimization problem of the expected number of outage users. We propose a trajectory control method based on genetic algorithm and particle swarm optimization method that solve the optimization problem. Furthermore, we evaluate the proposed method by simulation and demonstrate its effectiveness. |