# V2X Communication over Cellular Networks: Capabilities and Challenges
## 2 V2X Use Cases
Network-related requirements per UC are summarized in Table 2. In some cases, the delay, reliability, and throughput are reported as range values; this is done because multiple scenarios for different levels of autonomous driving are being considered, even in the context of the same organization. 3 GPP has specified more stringent requirements for most of the UCs, as the telecom experts want to prepare the networks for supporting all UCs, even those belonging to the highest level of driving automation. It should also be noted that there is not available information for all requirements. Our delay analysis in Section 4 assumes 3 GPP's values of Table 2, whereas the spectrum analysis in Section 5 considers 5 GAA's estimations, which, although typically assuming more modest values for services than their counterparts in 3 GPP, are sufficient for indicating existing issues. For the UC of \"Cooperative Driving\", we have assumed 3 GPP's value as 5 GAA has not yet defined one. Moreover, note that 5 GAA distinguishes the mode of communication in V2N/V2I (i.e., uplink (UL) and downlink (DL)) and V2V (i.e., sidelink), where this information is not defined in 3 GPP specifications. In the analyzed UCs, it should be noted that 3 GPP underlines the need to support automated driving in multi-Public Land Mobile Network (PLMN) environments; in 5 GAA, this is implied with the global geographical coverage, but it is not explicitly raised. As we will explain in the following sections, this is an important issue that may considerably affect the overall communication delay if not addressed properly. \begin{table}
\begin{tabular}{c c c c c} \hline
**UC \#** & **5 GAA UCs** & **3 GPP UCs** & **Description** & **Common Name** \\ \hline
1 & Vehicles Platooning in & eV2X support for & A group of vehicles driving closer & Platooning \\  & Steady State & vehicle platooning & in a coordinated manner & \\
2 & High-Definition Map & Automotive: Sensor & Sharing of raw or processed sensor & Sensor and State \\  & Collection and Sharing & and state map sharing & data to build a shared map & Map Sharing \\ \hline
3 & Tele-Operated Driving & Support of & Remote control of a vehicle & Remote Driving \\  & & remote driving & & \\  & & Cooperative & Cooperative vehicles’ & \\
4 & Cooperative Lane Merging & lane-change of & communication to change a lane or & Lane Change \\  & & automated vehicles & perform lane merging & \\
5 & Infrastructure-Assisted & Collective perception & Infrastructure transmits & Infrastructure-based \\  & Environment Perception & of environment & information about objects on the & Perception of \\  & & & road to the vehicles & Environment \\
6 & Vehicle Decision Assist & Cooperative collision & Enable collision avoidance & Collision Avoidance \\  & & avoidance & through coordinated maneuvers & \\ \hline
7 & High Definition & Information sharing for & Exchange high resolution data & \\  & Sensor Sharing & highly/fully & (e.g., video, lidar) for cooperated & \\  & & automated driving & manoeuvres to highest SAE levels & \\  & & Video data sharing for & Transmission of video during & See Through for \\
8 & See Through for Passing & assisted and improved & car overtaking & Passing \\  & & automated driving & & \\ \hline
9 & Cooperative Maneuvers of & Emergency trajectory & Exchange trajectory information & Emergency Trajectory \\  & Emergency Situations & alignment & among vehicles under & Alignment \\  & & Intersection safety & & \\
10 & Automated Intersection & information & Cooperative automated driving & \\  & Crossing & provisioning for & information exchange when & Intersection Crossing \\  & & urban driving & crossing an intersection & \\ \hline
11 & Coordinated, Cooperative & Automated cooperative & Exchange of information among & \\  & Driving Manoeuvre & driving for short & vehicles to coordinate their & \\  & & distance grouping & trajectories under & Cooperative Driving \\  & & different situations & \\ \hline \end{tabular}
\end{table} 
Table 1: Vehicle to Everything (V2X) use cases employed for delay and spectrum analysis.