# UAV Support for Mission Critical Services
## 4 Potential Roles of UAV in MCS
### Scenario 1  
In some mission-critical cases, additional connectivity and/or service platforms to the existing and properly functioning ones can be needed. Such scenarios include conducting a rescue action in the area where there is no access to any infrastructure-based networks or the existing connectivity, and the service platform does not support required services. It can concern unpopulated regions, deserts, tunnels, underground halls or cases when the rescue teams need to have dedicated connectivity and specific services. In such a case, the usage of UAVs can be considered in the phase of the MCS design. In general, UAVs can play triple roles in such systems:  
* _UAV as a transporter_. UAVs can move to areas where the presence of humans is dangerous (radiation, chemical toxins, bacteria, high temperature). Moreover, they can take some action depending on the capability of the robotic part of the drone. Thus, the delivery UAV can be used to install dedicated sensors and bring food, water, medicines, etc., to remote, non-accessible human locations. Several subsequent missions of such delivery UAVs can be needed to achieve the goal. For example, more complicated and larger devices can be transported by UAVs in several missions. As has been mentioned, the combined UAV-robot solutions for parcel delivery do not exist. A solution to this problem will be the transportation of a small, autonomic robot to the destination. Such an intelligent robot can assemble the delivered parts. * _UAV as a deployer of local wireless network or access network extension_. In this case, the UAV can transport and deploy a local base station that can provide connectivity combined with required services. There is an assumption that such wireless networks will use popular and standardized solutions to allow users equipped with commercial mobile network terminals to use the system. It mainly concerns WiFi and LTE--for both solutions, a'mobile' base station with a dedicated uplink can be provided in a small form factor. It can be a Private LTE variant that is simpler than the classical LTE version. As already mentioned, there exist on a market LTE complete solutions in the form of a backpack. The creation of a local network has, in some cases, value _per se_; however, in other cases, it may be needed to provide a link that connects the local wireless network with the external world. In most cases, such backbone links will be wireless. It can be created in two ways. The first lies in using the same wireless technology as the one used for local networks, but with a directional antenna that enables the creation of a relatively long-range link. This approach is well suited to WiFi networks. The second approach lies in using a gateway that connects the local network to the wide-area network. Such a solution can be created, for example, using pretty popular WiFi-LTE gateways (please note that in this scenario, proper functioning of infrastructure-based networking solutions is assumed). Another option is to use an LEO or MEO satellites as a backbone. As LEO, the Starlink solution can be used [47]. As in the previous case, the installation of the complete solution may require several UAVs flights to transport the base station, battery, antenna subsystem and a robot able to assemble these components. The UAVs with computing capabilities can be used as virtualized, mobile mini data centres with predefined MCS services. * _UAV as a deployer of dedicated sensors in remote locations_. Here, UAVs are used to deploy remote sensors needed to provide more information about the environment. There can be sensors of specific chemical substances, temperature, humidity, radiations, vibrations, etc. In most cases, such sensors' size and weight are insignificant. They can be deployed as independent nodes that record sensor(s) specific parameters and transmit them. In some cases, nodes that aggregate the sensor traffic and/or perform the role of a gateway to another network can also be used.