# Closing Connectivity Gap: An Overview of Mobile Coverage Solutions for Not-Spots in Rural Zones
## 3 Potential Solutions
### UAV-Assisted Networks
#### 3.1.2 Regulation  
The 3 GPP Association mainly tackles the protocols and regulations for UAS-FANET communication beneath the addressed need of the quickly maturing sector [103]. Consequently, in the eagerness to state new studies and new features for safe operations, there has been joint work with GUTMA, even involving the novel 5G framework use cases. To our best knowledge, Figure 6 introduces the areas that are being addressed in the latest 3 GPP Releases, from Release 15 to Release 17. \begin{table}
\begin{tabular}{p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline \hline
**Cite** & \begin{tabular}{c} **Approach** \\ **ML** \\ \end{tabular} & \begin{tabular}{c} **Scenario** \\ **UMa** \\ \end{tabular} & \begin{tabular}{c} **Method** \\ **UMa** \\ \end{tabular} & \begin{tabular}{c} **Atn** \\ **RMa** \\ \end{tabular} & \begin{tabular}{c} **Atn** \\ **St** \\ \end{tabular} & \
\begin{tabular}{c} **Atn** \\ **N-St** \\ \end{tabular} &
\begin{tabular}{c} **Contributions** \\ \end{tabular} \\ \hline
[95] & X & X & X & X & X & PL and Delay Spread prediction for mmWave channels. &
\begin{tabular}{c} • Low computational complexity. \\ • Full feature selection scheme. \\ • Frequency/scene-based transfer \\ \end{tabular} \\ \hline
[96] & X & X & X & X & X & PL and Shadowing effects analysis in 3D- LOS/NLOS Channel. &
\begin{tabular}{c} Unsupervised learning clustering \\ technique to derive a 3D temporary channel. \\ \end{tabular} \\ \hline
[97] & X & X & X & X & X & PL empirical prediction with environmental parameters. &
\begin{tabular}{c} • Location-based method by \\ using 3D-GPS coordinates. \\ • Learning phase includes \\ atmospheric conditions. \\ \end{tabular} \\ \hline
[98] & X & X & X & X & X & X & \
\begin{tabular}{c} Collaborative algorithm to solve \\ communication overload by \\ achieving 1.5x throughput. \\ \end{tabular} &
\begin{tabular}{c} Optimization of Multi-UAV user \\ deployment based in modified K- \\ means distribution and POO. \\ \end{tabular} \\ \hline
[99] & X & X & X & X & \
\begin{tabular}{c} 3D non-stationary geometry-based \\ stochastic channel model for A2G. \\ \end{tabular} &
\begin{tabular}{c} • 3D arbitrary trajectories. \\ • 3D antenna arrays for SG. \\ • Computational Methods for \\ time-variant channel parameters. \\ \end{tabular} \\ \hline
[100] & X & X & X & X & X & \
\begin{tabular}{c} A MIMO wideband truncated \\ ellipsoidal-shaped method with \\ scatterer consideration. \\ \end{tabular} &
\begin{tabular}{c} Statistical derivation of space- \\ time-correlation function and \\ Doppler power spectrum density. \\ \end{tabular} \\ \hline
[101] & X & X & X & X & \
\begin{tabular}{c} Geometrical model for UAV flight’s \\ Multi-Path Components evolution. \\ \end{tabular} &
\begin{tabular}{c} • Geometrical parametrization for \\ the main MPCs. \\ • Simulation under non-intuitive \\ effects of propagation. \\ \end{tabular} \\ \hline
[102] & X & X & X & X & \
\begin{tabular}{c} Spatial-temporal correlation in \\ function of UAV’s hover radius, \\ flight altitude, and elevation angle. \\ \end{tabular} &
\begin{tabular}{c} • Numerical approach of PL, \\ Multi-shadow fading, Doppler shift, \\ and channel correlation. \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Some efforts addressed in A2G modeling. There are other institutions concerned with developing UAS standards, such as GUTMA/GSMA, ASTM International, IEEE, ISO, EUROCAE, IETF, and JARUS [47]. For a handy insight on network safety, by avoiding a loss of service due to their proximity, we have briefly recapped the 3 GPP-suggested edges [103] in the Listing 1, as long as new releases emerge in supporting the LTE aim [48]. Release 15 addressed the research studies about the ability for UAVs to be served using LTE networks in addition to a comprehensive analysis of potential interferences between eNodeB and UAS. Release 16 has an overview of the potential requirements and use cases to enable the necessary connectivity between UAS and UTM.