# Unmanned Autonomous Intelligent System in 6G Non-Terrestrial Network
## 4 Application of UAV-Aided Non-Terrestrial Networks in UAIS
### Connected and Automated Vehicles in UAV-Aided NTNs
#### 4.2.2 6G NTN-Enabled CAV Capabilities
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Literature** & **Topics** & **Contributions** & **Limitations** \\ \hline \multirow{3}{*}{[143]} & Traffic monitoring in complex environments & Utilizing blockchain-based UAV/HAPS communication to assist traffic perception data transmission & The architecture of internet of drones need further study. \\ \hline \multirow{3}{*}{[144]} & Traffic monitoring in complex environments & Offloading/sharing decision making using a sequential game method & The edge computing architecture was not mentioned in detail \\ \hline \multirow{3}{*}{[145]} & Localization & Utilizing UAV-based method to assist localization & The moving vehicles and terrain blockage severely impact UAV–vehicle communication \\ \hline \multirow{3}{*}{[146]} & Localization & Achieve vehicle localization with signal strength with a swarm of UAVs & The interference and uncertainty of wireless channel hindered the reliability of communication. \\ \hline \multirow{3}{*}{[147]} & \multirow{3}{*}{Vehicle platoon control} & A sliding mode controller was proposed based on the observed vehicle states for longitudinal cooperation of CAVs & Inter vehicle information was not discussed. \\ \hline \multirow{3}{*}{[148]} & \multirow{3}{*}{Vehicle platoon} & Power allocation of uplink NOMA in vehicle platoon vehicle platoon & The platoon method needs in-depth discussion \\ \hline \multirow{3}{*}{[149]} & \multirow{3}{*}{Vehicle platoon} & Joint resource optimization and mobility control of UAV-aided vehicles platoon & The role of vehicle platoon in MEC require in-depth study \\ \hline \multirow{3}{*}{[150]} & \multirow{3}{*}{Vehicle platoon} & Joint Communication and Computation Resource Scheduling of a UAV-Assisted Mobile Edge Computing System for Platooning Vehicles & The wireless power transmission mechanism of vehicles require investigation. \\ \cline{3-5}  & & An energy consumption & \\ \cline{1-1} \cline{3-5}  & & & \\ \cline{1-1} \cline{3-5}  & & & \\ \cline{1-1} \cline{3-5}  & & & \\ \hline \multirow{3}{*}{[151]} & \multirow{3}{*}{Vehicle platoon} & An energy consumption minimization-based resource management paradigm was proposed & The platoon method of the ground vehicle was not covered \\ \cline{1-1} \cline{3-5}  & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Summary of previous work concerning CAVs in 6G NTN communication. The existing literature on NTN V2X applications is summarized in Table 4, along with the challenges and unresolved issues of the mentioned works. As shown in Table 4, the use of NTN-based V2X technology can enhance tasks such as localization, perception and object detection through NTN communication. CAVs can maintain reliable and high-throughput connections through NTN V2X communications in areas with insufficient terrestrial infrastructure for real-time traffic information interactions. This significantly enhances the safety and reliability of fully automated transportation systems. Based on data from V2X communications, CAVs are capable of controlling themselves in a safer manner, thereby avoiding accidents and road damage that occur beyond the line of sight of onboard sensors. However, the growing complexity of V2X communication systems also raise concerns about security problems, particularly in UAV air-to-ground channels. With the advancement of CAVs and NTN communication technologies, the realization of an autonomous transportation system will be established in both cities and remote areas. With the support of UAVs, the overall safety of intelligent transportation systems will be enhanced through early warning and air-to-ground cooperation [152; 153; 154; 155; 156]. Intelligent Reflection Surfaces (IRS) are an emerging field that has drawn much attention from researchers in the 6G mobile communications field. In addition to the successful implementation of UAVs in V2X connections, IRS shows promise as a communication relay in V2X scenarios. It can be deployed as an aerial IRS with UAVs or other aerial vehicles serving as payload platforms.