Managing Critical Nodes in UAV assisted Disaster Networks

Device-To-device (D2D) communications serve as an alternative to cellular networks to enable communication for public safety networks (PSNs). A key requirement for PSNs is to offer alternative access to reach the responders if the communication infrastructure is partially or completely damaged due to a natural or man-made disaster. In this paper, we propose a novel unmanned aerial vehicle (UAV) assisted solution to ensure energy-efficient D2D connectivity in the disaster zone in the presence of critical nodes (CNs). The results show that the minimum average outage is achieved when the UAV is placed at the center of the region associated with the UAV, however, this scenario completely changes with the presence of CNs. Initially, with an increase in the number of CNs, the optimal UAV position shifts from the centre, however, increasing CNs causes the UAV to converge back to the center of the UAV associated region. To cater the service requirements of CNs, we analyze the impact of increasing the mobile command center (MCC) coverage range and study its impact on UAV placement by varying the ratio of CNs and non-CNs. We found that the average outage probability decreases with the increase of the MCC range.