  The malfunction or interruption of wireless coverage services has been shown
to increase the mortality rate during natural disasters. Wireless coverage by
an unmanned aerial vehicle (UAV) provides network coverage to ground user
devices during and post-disaster events. The relay hops receive wireless
coverage and can be forwarded to user devices that are out of coverage allowing
reliable connectivity for large-scale user devices. This work evaluates the
optimal relay hops performance to improve wireless coverage services and
establish connectivity in post-disaster scenarios. The results demonstrate the
UAV line of sights understanding to select an optimal relay for improving
wireless coverage services. The path loss probability and system capacity were
all affected by the user device distance and relay densities. The optimal relay
hop distance and the UAV positions static are also investigated to improve
coverage likelihood which could be especially useful for UAV deployment design.
It is found that the dense relays node in UAV systems enhances the capacity
coverage area and energy efficiency by decentralized connectivity through a
multihop device to device wireless network.
