Public safety communication (PSC) is extremely vital during Emergency situations to coordinate and communicate effectively among emergency responders to save lives and to avoid confusion at the scene. Despite the vast advancement in commercial communication systems, scant attention has been paid to PSC networks. Furthermore, the most PSC agencies (such as Fire and Rescue, Police, Emergency Medical Services, etc.) use their own separate networks to communicate while handling emergency situations. These separate networks are not fully interoperable with each other and can also be suffered by interference due to a large number of devices operating during natural disasters. In the US, a recent bill from Congress and the FCC has provided the groundwork for the creation of a nationwide broadband public safety communication network by assigning 700MHz frequency band with an aim of building a unified broadband communication network for public safety operators.
PSC can help plan beforehand for different things such as floor plans, civilian information, scene analysis, and so on. In these scenarios, unmanned aerial vehicle (UAV)-assisted cognitive radio enabled communication networks can help to improve the overall network performance by replacing destroyed infrastructures by UAVs. The UAV networks can be deployed by implementing suitable UAV packing to find the optimal number of UAVs to cover the region and by providing geo-location to route the UAVs to the target location to recover communications in the affected area. UAVs also have the advantage of being airborne, allowing for better line of sight with ground users and being able to establish the network on the fly. Furthermore, cognitive radio enabled UAVs can identify suitable frequency bands (least interfered or idle bands) to communicate with each other or with first responders or civilians. Mathematical and numerical analysis suggest that significant improvements in capacity and throughput can be achieved by deploying UAV network to reconnect the destroyed network to backhaul even in low SINR region since the users are closer to the cognitive radio enabled UAV base stations.