Fair Communications in UAV Networks for Rescue Applications

We study the deployment of an unmanned aerial vehicle (UAV) network to provide urgent communications to people trapped in a disaster zone, where each UAV is an aerial base station in the air. Unlike most existing studies that assumed that each user communicates with a UAV directly, we introduce Device-to-Device (D2D) communications, in which a user within the communication range of a UAV can serve as a hotspot (e.g., WiFi hotspot), and provide communication services to his nearby users who are out of the communication range of any UAV. More users thus can have the communication service provided by the UAV network. To ensure that the users within and out of the communication ranges of deployed UAVs have fair communication quality, we study a novel UAV deployment and resource allocation problem under the D2D communication model, which is to deploy K given UAVs in the top of a disaster zone, allocate the bandwidth of each UAV to its served users, allocate the bandwidth of each hotspot to his served users, determine the data rate of each user, and find the routing paths for data transmissions, such that the accumulative utility of all users is maximized. We also propose a novel (1 - 1/e - ε)-approximation algorithm algMaxUtility for the problem, where e is the base of the natural logarithm, and ε is a given constant with 0 < ε < 1 - 1/e. We finally evaluate the performance of the algorithm. Experimental results show that accumulative utility by the algorithm is up to 18% larger than those by existing algorithms. In addition, more than 16% users are served in the deployed UAV network by the proposed algorithm. © 2023 IEEE.