# Advancing C-V2X for Level 5 Autonomous Driving from the Perspective of 3 GPP Standards
## 5 SA-Based 5G V2X Services
### System Support
#### 5.1.3 Application Layer Support  
The advancements promised for future generations are not only happening in communication technologies but in V2X scenarios focusing on real-world use cases. In Section 4, we discussed functional architecture, procedures, and information flows from technical document (_TS 23.286 Rel-16_). Considering the era of 5G, we present VAE layer support for 5G V2X services from the technical specification (_TS 23.286 Rel-17_). This specification considers existing studies i.e., _TR 23.795_, _TS 22.185_, and _TS 22.186_, etc., for architectural requirements, functional models, deployment models, identities, procedures and information flows, and VAE layer APIs. In addition, it provides the VAE capabilities application to EPS and 5 GS.  
The _Rel-17_ document provides updates to the technical specifications such as V2X UE registration enhancement; V2X UE identity; session-oriented services; UE initiated session-oriented service; network monitoring procedure enhancement; UE-to-UE broadcast/groupcast configuration by VAE layer; support for enhancements to V2X group management and group communication; V2V communication mode switching; support for HD map dynamic information; dynamic local service information in multiple V2X service provider; V2X application layer architecture enhancement; PC5 Provisioning in multi-operator V2X scenarios; V2X service discovery across multiple V2X service providers; clarifications for network monitoring information notification; clarifications on network monitoring; business relationships between V2X service providers; monitoring and control of QoS for eV2X communications; and update to VAE server APIs.  
Rel-17 (_TR 21.917_) specifies updates to technical specifications. These are; V2V communication assistance when mode switching to enable provisioning the V2X UE to use V2V communication modes switching from V2X application-specific layer. Cross-service provider discovery for V2X to allow V2C UE's to find V2X services from a service provider while roaming outside the primary service provider coverage area. Retrieving dynamic local service information from a V2X UE through a service provider. Dynamic group information update for V2X platooning. The multi-agent scenario that supports PC5 provisioning for V2X/V2I communication. HD map dynamic information to enable V2X HD map server that obtains dynamic object information. V2X application server accesses the VAE layer services to disperse UE to UE groupcast/broadcast policy configurations and messages that are now enabled by UE to UE groupcast/ broadcast configuration and messages delivery services. V2X communications using local MBMS via the VAE layer are now supported. ToD application session management requirements are served using session-oriented services, the ToD may rest in UE or inside an application server. Extended QoS and Service adaptation is used for simplified service requirement adaptation service that is geared toward the V2X application server as the details of 3 GPP system interactions are abstracted for the user.