ng a high-definition movie while a back- ground application detects a road hazard and triggers an emergency message for the cars behind or nearby to slow down or stop to prevent an accident. Fig. 7.9 illustrates this scenario. The slices could come from one device or multiple devices. In the case of one device, 3GPP has defined that a given device can support up to eight different slices with a common access and mobility management function (AMF) for all slices and a session management function (SMF) per slice. In the example shown in Fig. 7.9, there are three network slices attached to the same device sharing the same AMF instance. The first slice is massive machine-type communication, which sends data to the core and the PDN. The second slice offers caching at the edge, while the third slice provides access to an edge V2X application. The C-V2X can operate outside of network coverage using direct communication without requiring provisioning of a universal subscriber identity module (USIM). To enable USIM- less communication, automobile manufacturers will preconfigure the vehicle device with parameters necessary for out-of-network operation, including authorization to use V2X; a list of authorized application classes and the associated frequencies to use; radio parameters for use over the direct link; and configuration for receiving V2X messages via cellular V2X Control Slice function orchestration URLLC: Safety/Self-driving service management (Ultra-reliable and low latency) V2X App URLLC slice NFV MANO ((III) Caching eMBB slice eMBB: Infotainment/Video streaming mMTC slice (Mobile broadband) mMTC: Maintenance/Statistics High-density and low throughput NFVI (Edge cloud) NFVI (Core cloud) Figure 7.9 Example of NR V2X network slicing [13,14]. Vehicle-to-Everything (V2X) Communications V2X App V2X App LTE-Uu (Stationary) V2X UE V2X App V2X App Server Local Gateway (L-GW) V2X UE LTE-Uu Figure 7.10 RSU implementation options [20]. broadcast (i.e., eMBMS). Direct USIM-less communication allows C-V2X to support criti-