Optimizing InterCluster Flights of PostDisaster Communication Support UAVs In the aftermath of largescale disasters, critical communication infrastructure is often destroyed. Ad hoc networks can restore wireless communication with basic functionalities, especially for civilians in the affected areas. However, as humans form groups and tend to stay around important locations like shelters in such situations, the network is highly intermittent. Autonomous Unmanned Aerial Vehicles can act as controllable and highly mobile data carriers between separated network clusters to enable delaytolerant intercluster communication. A possible heterogeneous set of usable aerial vehicles and the necessity to adapt the system to various environments requires the system to be highly flexible. Combined with severe constraints in energy usage or number of available vehicles, there is a need to increase the efficiency of intercluster flights. In this paper, we present approaches to optimize intercluster flights based on communication performance and energy efficiency. The resulting optimization model is a powerful tool for operators to adjust system settings to match required demands.

UAVaided Networks for Emergency Communications in Areas with Unevenly Distributed Users Nowadays, humanxe2x80x99s daily life and various networks are closely intertwined. When natural disasters or malicious attacks break out, the failure of communication infrastructure due to direct destroy or indirect impact tends to cause the massive outage of communications. Emergency communication networks will play a significant role in rescue operations. Recently, a flexible and efficient solution has been provided for emergency communications by the use of unmanned aerial vehicles (UAVs). By means of their excellent characteristics, UAVs, serving as aerial base stations (ABSs), can be deployed rapidly to temporarily rebuild the damaged communication network to restore the usersxe2x80x99 connectivity. In this paper, we investigate the use of UAVs as ABSs for an emergency communication scene where user equipments (UEs) are unevenly distributed and the communication infrastructure is completely failed due to a severe disaster. Effective communication probability (ECP), which integrates throughput coverage and connectivity, is used to evaluate the performance of a communication network. Through simulations, we analyze the communication improvements that can be obtained by the flexible deployment of ABSs. The results show the noticeable increase in ECP when some ABSs are deployed in optimal locations.