Cellular-V2X (C-V2X), encompassing LTE-V2X/LTE-eV2X that evolves from LTE mobile network and NR-V2X that smoothly evolves from 5G New Radio, is a 3GPP-based (3rd Generation Partnership Project) global vehicle wireless communication technology.
Compared to DSRC-based V2X, C-V2X is a late starter. The concept of C-V2X first came out in 2013. It was not until 2015 that C-V2X standardization was officially initiated. The functional freeze date of 3GPP Release 14 was in June 2017. Rel-14 work introduces LTE support for V2X services, especially support for V2V services based on LTE sidelink. It mostly targets to provide data transport service for basic road safety service. 3GPP Release 15, as the first full set of 5G standards, was completed in 2018. Rel-15 work enhances LTE-based V2X services and specifies 3GPP V2X Phase 2 to support advanced V2X services in a fully backward compatible manner with Rel-14 V2X.
At the meeting ending on July 3, 2020, 3GPP Release 16 was completed with both the Stage 3 freeze and the ASN.1 and OpenAPI specification freeze being approved. Rel-16 work specifies architecture enhancements for 3GPP support of advanced V2X services, application layer support for V2X services and 5G V2X with NR sidelink. 5G V2X with NR sidelink in Rel-16 work corresponds to 3GPP V2X phase 3, which is the evolution of LTE-V2X in Release 14 (phase 1) and 15 (phase 2). 3GPP is in its final stage of completing Release 16 while simultaneously engaging in detailed discussions and decisions on Release 17. More 5G system enhancements are set to follow in Rel-17, with target delivery in July 2021. Rel-17 will further enhance NR sidelink communication for V2X in order to support requirements and operation scenarios not fully covered by Rel-16 sidelink. With the continuous enhancements and evolution, more versatile version of releases will come out to regulate as well as propel the commercial deployment of C-V2X communication.