In Europe, the 5.9 GHz band has been designated for safety-related intelligent transportation systems (ITS) in a technology-neutral manner in the range 5875-5935 MHz, according to CEPT/ECC Decision (08)01 and EU Decision 2020/1426. Additionally, the 5855-5875 MHz frequency band has been enabled for non-security ITS applications through the same ECC Recommendation (08)01. However, it is not clear how the coexistence of ITS-G5 and c-v2x can be achieved in that frequency band. One option could be to adopt a priority-based framework for ITS channels, which could allow adjacent operations of the two technologies (ITS-G5 and c-v2x).
Two wireless communications technologies, DSRC (Dedicated Short Range Communications) and C-V2X (Cellular V2X), are being considered as solutions to implement V2X communications. DSRC or ITS-G5 (in Europe) is a term that describes short- to medium-range and bidirectional wireless communications technologies for vehicular environments, with interoperability between vehicles, road infrastructure and other compatible devices.
The most advanced implementations of DSRC are based on IEEE 802.11p, an extension of the Wi-Fi standard (802.11) that adapts the medium access control (MAC) and physical (PHY) layers specifically to the needs of V2X communications, including operation in a highly dynamic and mobile environment, direct transmission of messages in an ad-hoc manner, low latency and use of a reserved frequency range.
As of the first quarter of 2019, several automakers, including Toyota, GM (General Motors), and Volkswagen, have equipped their vehicles with advanced DSRC technologies. It is also important to note that DSRC’s legacy technologies for V2I (vehicle-to-infrastructure) applications, primarily electronic toll collection (ETC), have been in operation in multiple markets around the world since the 1990s. C-V2X ( Cellular V2X) C-V2X was developed specifically for transportation security applications by the telecommunications industry, subsequently standardized by automotive and transportation stakeholders at the application layer, and is rapidly gaining global recognition. A group of standards families support C-V2X: C-V2X based on LTE, as specified in 3GPP Release 14 (published in 2017) and Release 15. C-V2X based on 5G and NR, as specified in 3GPP Rel- 16 and with continuous evolution in future versions.