Resource Allocation for UAV-Aided Disaster Emergency Communication

This dissertation explores the utilization of Unmanned Aerial Vehicles (UAVs) for expanding wireless coverage in civilian applications, particularly real-time moni-toring, search and rescue, and disaster response. UAVs can function as aerial base stations, restoring connectivity during emergency cellular network outages. They can also augment existing ground infrastructure to enhance cov-erage and data rates for users. However, limited battery capacity necessitates periodic recharging of UAVs. This dissertation addresses the challenge of mini-mizing the number of UAVs required for continuous coverage of a designated area, considering the con-straints of recharging time, travel time, and the num-ber of subareas encompassed by a single patrol cycle. Due to the inherent com-plexity of the problem, a graph-partitioning approach is proposed. The coverage graph is divided into cy-cles originating from the charging station, and the minimum number of UAVs needed to traverse such a cycle is determined based on the parameters above. An efficient algorithm is then developed to solve this optimization problem. The dissertation subsequently investigates the optimal placement of a single UAV for minimizing the total transmission power required to ensure wireless cov-erage for indoor disaster victims. Two practical scenarios are analyzed, and effi-cient solutions are presented for each. Recognizing the limitations of a sin-gle UAV's transmit power, the dissertation further explores minimizing the number of UAVs needed for comprehensive indoor coverage. An efficient algo-rithm is pro-posed to address this challenge. Finally, the dissertation examines the maximization of indoor wireless cov-erage using UAVs equipped with directional antennas. To prevent signal interfer-ence while operating on a single channel, non-overlapping coverage areas are pri-oritized. Two deployment methods are presented for UAV place-ment, considering coverage from one or both building sides. The results demon-strate that strategi-cally placing UAVs in an upside-down configuration can sig-nificantly improve total coverage compared to single-sided deployment.