# UAV-Based Privacy-Preserved Trustworthy Seamless Service Agility for NextG Cellular Networks
## 1 Introduction  
Literature in the area of Next Generation (NextG) wireless communications demonstrated the desperate need for more bandwidth, enhanced connection reliability, and security. NextG networks should offer a much better user experience enabling extended coverage and seamless mobility. Accordingly, the NextG cellular infrastructures are expected to serve various heterogeneous end-users with a large set of dynamically changing requirements, capabilities, and constraints. Given the high mobility nature of such devices, such as Unmanned Aerial Vehicles (UAVs), it would be a waste not to take advantage of such devices' existence to support the infrastructure operation in case of need. In situations such as white or red spots, the infrastructure fails to serve the users in need. A white spot describes a tower failure due to intentional (e.g., terrorist attack) or unintentional (e.g., a natural disaster) causes. A red spot describes an unexpected excessive traffic demand that overwhelms the cellular tower and reduces service quality. Red spots can easily happen in areas where big events are happening (e.g., game days or celebrations). In the case of white spots, the situation becomes critical and life-threatening. In disaster situations, cellular service can be a key to saving many lives. In such situations, expecting user interactions to obtain better service or even basic coverage might not be realistic due to the high stress entailed or the inability to move. Users must have adequate coverage to ask for help or provide help. In white or red spots, the infrastructure endpointsrepresented by the cellular towers might be either overwhelmed or disabled. Flying UAV-carried towers are considered to be one of the best possible solutions to provide coverage in white spots [1; 2]. Furthermore, introducing service agility where service providers can accommodate users from other networks can provide a suitable alternative for infrastructure damage or unavailability. One of the many new features designated to the NextG standard over former generations' standards is the service-oriented architecture that relies on network slicing and virtual network functions [3]. The network slicing provides traffic isolation functionality and supports network flexibility and service agility [4]. In this work, we propose an extended feature to be added to the 5G structure that will take the NextG service agility to the next level of seamless communication. We propose inter-operator service agility that blends service providers into one logical network with an enhanced low latency communication performance. All the base stations (gNodeBs and eNodeBs) from different service providers are expected to provide service to users from different home networks to enhance the end-user experience. This added feature also permits seamless communication with inter-operator agility cooperative cellular environment, which provides reliable coverage to all users in overwhelming traffic situations. Nevertheless, the new service-based structure, including our proposed added feature, has many obstacles holding it from emerging to the current commercial 5G cellular standard. The most irritating and significant concerns for such dynamic service agility are security and user privacy. Moreover, our proposed transition between service providers implicates high-security risks and possible privacy leakages. Therefore, assuming full trust in such heterogeneously managed and operated formation is not realistic. Fake base stations can be easily deployed to take advantage of such overrated trust and enable eavesdropping or massive service disruption. Not to mention the attackers are interested in user tracking and traffic-profiling, allowing them to learn and monitor users' sensitive information. Additionally, cellular network privacy regulations prevent distributing users' information and IDs between different service providers, which impedes our proposed inter-cooperation between base stations of different service providers.