# Recharging of Flying Base Stations using Airborne RF Energy Sources

## TL;DR

This paper proposes a novel wireless recharging method for UAV-based flying base stations using airborne RF energy sources, optimizing placement for power maximization and fairness.

## Contribution

It introduces an optimal placement strategy for airborne RF energy sources to efficiently recharge UAVs without disrupting their trajectories.

## Key findings

- Optimal placement maximizes received power and fairness for even number of sources.
- Using an odd number of sources involves trade-offs between power maximization and fairness.
- Optimal placement yields significant power gains over nonoptimal configurations.

## Abstract

This paper presents a new method for recharging flying base stations, carried by Unmanned Aerial Vehicles (UAVs), using wireless power transfer from dedicated, airborne, Radio Frequency (RF) energy sources. In particular, we study a system in which UAVs receive wireless power without being disrupted from their regular trajectory. The optimal placement of the energy sources are studied so as to maximize received power from the energy sources by the receiver UAVs flying with a linear trajectory over a square area. We find that for our studied scenario of two UAVs, if an even number of energy sources are used, placing them in the optimal locations maximizes the total received power, while achieving fairness among the UAVs. However, in the case of using an odd number of energy sources, we can either maximize the total received power, or achieve fairness, but not both at the same time. Numerical results show that placing the energy sources at the suggested optimal locations results in significant power gain compared to nonoptimal placements.