Vehicle-to-Everything (V2X) is expected to play a significant role in autonomous driving. Currently, there are two radio technologies available for V2X communication: Dedicated Short Range Communications (DSRC) and Cellular V2X (C-V2X).
DSRC technology is a Wi-Fi variant known as 802.11p, operating in the 5.9 GHz band. Historically, DSRC-based V2X was supported by the US FCC (Federal Communications Commission) dating back to 1999 and its standard drafting began from 2004. With decades of development, DSRC-based V2X is mature in terms of technology and commercialization readiness.
C-V2X, encompassing LTE-V2X (LTE refers to Long-term-evolution, LTE-V2X is 4G-based V2X) and 5G-V2X, is a 3GPP-based global vehicle wireless communication technology evolving from 4G and 5G cellular network. Though its research began far later than DSRC, with standard drafting starting in 2015, C-V2X gains second-mover advantages in many perspectives.
DSRC-based V2X vs. C-V2X
C-V2X provides levels of security, communication range, latency and reliability proven to be superior to the capabilities of DSRC-based V2X.
C-V2X utilizes the comprehensive coverage of existing cellular networks, reducing the investment in roadside infrastructure.
DSRC-based V2X merely supports V2V and V2I applications, while C-V2X can in addition harness cellular network to connect with pedestrian and network.
In the past years, countries and organizations have been choosing between two technologies, and C-V2X seems to gain more favors in the competition. In June 2018, the Ministry of Industry and Information Technology (MIIT, China) issued the Frequency Management Regulations that determined the working frequency and usage requirements for C-V2X. In July 2019, European Union rejected a European Commission plan to mandate WiFi-based (802.11p) ITS-G5 standard as the requirement for V2X capabilities, which opened the door to C-V2X technology. In December 2019, the US FCC approved to allocate specific portions of the 5.9GHz band to C-V2X devices.
Choosing C-V2X or DSRC is still an open question in most countries, but it is undeniable that the excellent performance and cost effectiveness are giving C-V2X great advantages over DSRC-based V2X.