## 5 Application Scenarios  
In this section, relevant aerospace scenarios described in the literature will be reviewed, along with network architectures supporting those scenarios. As anticipated, the SAGIN paradigm, sometimes referred to as Space Information Network (SIN), should be considered as the main reference [197; 198], encompassing the challenging interworking of space systems, aerial networks, and terrestrial communications. Resources in the three network segments are limited and unbalanced [197], thus requiring careful design for the integration to be successful. The investigated scenarios and enabling components are summarized in Table 5 and are discussed below. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Name** & **References** & **SAGIN Role and Relevance** \\ \hline Autonomous Driving & [50] & support terrestrial networks in meeting QoS level; on-demand resources and services to be deployed \\ \hline Smart City & [18; 50; 199] & provide coverage extension services, on-demand bandwidth, monitoring services, mobile crowdsensing; monitoring capabilities and fast deployment in fast-changing environments (such as cities) \\ \hline IoRT & [18; 26; 200; 201] & remote IoT scenarios (connectivity, custom services); NTN nodes are the most viable option \\ \hline IoV & [202; 203] & on-demand resources and services to be deployed; coverage in poorly connected areas \\ \hline Healthcare services & [26; 200] & telemedicine and e-health services; coverage in poorly connected areas \\ \hline Maritime monitoring & [26; 200] & life-saving support, deep sea exploration, under sea research activities, real-time command and control of autonomous ships; only viable connectivity option \\ \hline Energy distribution & [200] & control of critical energy infrastructures; monitoring in remote/not covered areas \\ \hline Continuum indoor-outdoor localization and positioning & [204; 205] & realization of an integrated indoor-outdoor localization and positioning system, working in the absence of GNSS capabilities or in urban canyons \\ \hline Coverage extension & [50] & deploy and use of NTN nodes to provide (additional) coverage to high-traffic or uncovered areas to support user services or to complement/substitute the terrestrial infrastructure \\ \hline Mobility management & [26; 197] & predict and control the 3D mobility of NTN nodes mobility to guarantee user QoS; orchestration and management to reduce link interruptions \\ \hline Enabling technologies and services & Task scheduling and offloading & [26; 50; 197; 201; 202; 203; 204; 205; 206; 207; 208] & offload task to NTN nodes to save local computational resources or to run too intensive tasks, scheduling them to respect QoS level; on-demand additional computational power to be deployed \\ \hline Mobile crowdsensing and MEC & [18; 26; 202; 209] & mobile crowdsensing to safeguard the network from edge caching issues; UAVs as base stations for services to other UAVs or ground/satellite stations \\ \hline Caching and on-the-fly data center & [26; 206; 209] & NTN nodes providing caching capabilities to guarantee low delay; edge capabilities in combination with remote cloud support \\ \hline \hline \end{tabular}
\end{table} 
Table 5: SAGIN-related relevant scenarios and enabling technologies in the literature. Some common application scenarios by leveraging SAGINs and key services offered by the network infrastructure at different layers of the SAGIN are graphically illustrated in Figure 9. Focusing on the current 5G deployment [210] and the ongoing work for the definition of the 6G standard [211], it is evident that different radio access technologies, also including the satellite component, are needed for such integration. Terrestrial services can be augmented with the development of VHTS systems and LEO mega-constellations to meet stringent requirements, such as high bandwidth, low latency, and increased coverage.