Is C-V2X Overtaking DSRC in Vehicle-to-Vehicle Communications?March 05, 2019 by Gary Elinoff
DSRC has been the V2V standard, but notable companies have recently focused on the newer C-V2X platform.
DSRC has been the standard vehicle-to-vehicle communication in development for decades, but several well-known automakers, chipmakers, and test & measurement companies have recently switched focus to the newer C-V2X platform.
Following in the lines of VHS vs. Betamax or Blu-Ray vs. HD DVD, the next great format war may be over V2X.
V2X stands for "vehicle-to-everything" where “everything” is anything relevant to the vehicle’s safe and efficient operation. This largely involves communications with nearby vehicles and the traffic control system. It is a nascent technology, and its progress will ultimately be dependent on the development of 5G, with its vastly reduced latency over present-day 4G. 5G will also make communication via the cloud easier and more efficient, opening up even more potential uses.
Examples of V2X capabilities. Image courtesy of Siemens.
DSRC vs. C-V2X
At present, there are two very different technologies enabling V2X:
- DSRC stands for dedicated short-range communications. It is also called ITS-G5 in Europe. In the US, DSRC is contained in a 75 MHz segment of the 5.9 GHz band. It is used for direct communications between moving vehicles and depends on neither the cloud nor cellular infrastructure.
- C-V2X stands for cellular V2X. It utilizes cellular technology to provide the link between the vehicle and the rest of the world, including other vehicles and the traffic control system.
The promise of vehicle-to-vehicle (V2V) communications in particular is greater safety. The University of Michigan's Transportation Research Institute estimates that DSRC could avert two million crashes by 2030, saving thousands of lives.
Graph showing estimated crashes avoided by implementing DSRC. Image courtesy of the University of Michigan Transportation Research Institute.
V2X offers the promise of V2V safety as well as communication with other sources about road conditions, weather, traffic patterns, pedestrians, cyclists, and even with smart cities.
Critics worry about the security of the technologies, as the low latency and open network required for V2X communication make components susceptible to hacking and GPS monitoring.
The Battle for Widespread Adoption
DSRC still has a firm hold in the automotive application landscape. In 1999, the FCC granted the aforementioned 75MHz segment for "intelligent transportation services to improve highway safety and efficiency," which was used to develop DSRC. And two years ago, the federal government proposed mandating V2V in new cars, with a focus on DSRC.
With this long development history, DSRC has some advantages as a platform. First deployed in 2017, it is already in mass market use. The Association of Global Automakers strongly supports the use of DSRC, a weighty endorsement as their membership includes Nissan, Honda, Subaru, Kia, and Toyota, among others.
Yet some automakers believe there is more potential with C-V2X, especially with the promise of 5G in the near future. Ford and BMW each announced their intent to proceed with C-V2X. Qualcomm and Ericsson have also announced their intention to produce C-V2X solutions.
However, C-V2X has not been as extensively tested as DSRC and does not have a dedicated MHz band. It must undergo many rounds of development before it can be widely deployed.
As the possibility of standardization approaches, warring publicity campaigns are emerging. In Europe, a coalition of intelligent transport solutions manufacturers has launched the "ITS-G5 It's Ready To Roll" campaign aimed at policymakers. And the 5G Automotive Association (or 5GAA) counts Audi, BMW, and Ford as members and advocates for C-V2X, giving presentations at MWC and demonstrations at CES to support their cause.
The Engineer's Dilemma
In the midst of a platform war, engineers must choose which platform to commit their development time and costs to. In some cases, the availability of components or test and measurement solutions can determine which side developers pick.
Several companies have announced collaborations focusing on C-V2X testing.
Keysight and Nordsys recently announced a partnership to combine Keysight's C-V2X Test Solution with the waveBEE Stack from Nordsys that enables V2V and vehicle-to-infrastructure (V2I) networking. This combination will provide a comprehensive testing platform that meets all automotive industry requirements.
And auto tech company Savari's C-V2X middleware will run on device-under-test on T&M manufacturer Rohde and Schwarz's R&S CMW500 for 3GPP LTE-V2X PC5 interoperability testing. Using a new software tool for simulation, the R&S CMW500 will support Savari's MobiWAVE V2X software stack for interoperability testing in a lab environment.
Combining DSRC and C-V2X
One new chipset makes the choice easy—both! Through a collaboration with CEVA, Autotalks is augmenting its existing DSRC chipsets with C-V2X capability.
Autotalks, a provider of V2X chipsets, has deployed CEVA’s CEVA-XC SDR DSP technology to unify DSRC and C-2VX in a single solution. It accomplished this by adding C-V2X Rel. 14/15 support to the CEVA-XC DSP based Autotalks chipset.
By utilizing CEVA’s software-defined capabilities with its existing technology, Autotalks addresses the need to encompass both C-V2X and DSRC in one package.
Autotalks offers the first global DSRC and C-V2X solution. Image courtesy Autotalks.
The collaboration represents the first pairing of these very different yet overlapping technologies in one package. The payoff for designers will be a reduction of development, integration and certification effort for global V2X deployment.
Amos Freund, VP of R&D at Autotalks, commented that: “The CEVA-XC DSP allowed us to quickly and seamlessly implement C-V2X support on our chipset in addition to DSRC, resulting in the world’s first and only truly secure global V2X solution.”
Specifically, the new V2X chipset supports both DSRC based on 802.11p/ITS-G5 standards as well as C-V2X based on 3GPP specifications. In addition, the new chipset is automotive qualified at AEC-Q100 grade 2, so it can reliably stand up to anything that the tough automotive environment throws at it.
Customers will be able to effortlessly toggle between DSRC and C-V2X communications. In addition, the chipset isolates V2X from the cellular Network Access Device (NAD), which provides many advantages, not the least of which is assuring that any demands made by the vehicle’s infotainment system for bandwidth will not be able to override the needs of any vital safety-related function.
Do you have any experience with either DSRC or C-V2X? Which technology do you think holds the most promise for V2X? Let us know in the comments!