Although the road towards full autonomous driving on all public roads is long and steep, many of the technologies are being deployed much sooner to enhance safety, navigation and congestion control. A sub-plot has been the contention between the rival cellular C-V2X and WiFi-based DSRC standards for automotive connectivity standards, with the tide now flowing strongly towards the former, after the latter made the early running.
Two recent developments highlight this, one in Europe and one in the USA, which were both fertile territory for DSRC, by contrast with China, which has put full weight behind C-V2X from the outset. In the USA, regulator FCC published a document this month confirming that revised rules to repurpose the lower 45 MHz of the 5.850-5.925 GHz band (5.9 GHz band) for the expansion of unlicensed midband spectrum operations, while handing over the upper 30 MHz to C-V2X, would come into effect on July 2.
This reaffirmed the FCC decision in November 2020 to split that 75 MHz of spectrum that was all originally allocated to DSRC, and hand 40% of it to C-V2X. That elicited some kickback from parts of the industry that had taken the DSRC route, remembering that in 2016, the US Department of Transportation (DOT) had recommended that the WiFi-based technology be mandated for inclusion in all new vehicles. The Trump administration appeared to favor the C-V2X direction but it was China’s refusal to countenance DSRC at all that may have been telling and persuasive in peeling away those major automotive makers that were in that camp.
Ford, Toyota and GM have all come over in varying degrees to the C-V2X side, while Volkswagen, the major automotive OEM holding out strongest for DSRC, has had to give way to C-V2X for its 40%-owned Chinese joint venture with that country’s SAIC Motor.
Meanwhile, as was also well reported, the European Union caved into pressure during 2019 to stop making ITS-G5, a version of DSRC, mandatory. That was interpreted as a victory for the 5G lobby but the EU resisted pressure to go the whole hog and switch full square behind C-V2X, instead adopting a technology neutral stance. This has left DSRC still in the game, reflected by recent publication of a paper by the Institution of Engineering and Technology (IET) advocating a hybrid version of V2X (vehicle to everything) wireless transmission, supporting both DSRC and C-V2X.
The argument was that some projects in Europe, the USA and Japan were still using DSRC so there would be a need for interoperability, compatibility and coexistence between the two. As the paper put it: “Now that C-ITS (Cooperative Intelligent Transport Systems and Services) will have more than one option for its V2X communications, its functional and technical problem domains surrounding the integrity of the available or proposed radio access technologies have become more tangled. This leads to a major research gap that is how to ensure integrity in operations of radios of competing technologies for uncompromised hybrid V2X in the 5.9 GHz spectrum.”
The work presented in the paper would be very valuable in the event DSRC survives as a major V2X technology, but that is now doubtful. Indeed, the other development we mentioned at the beginning relates to European trials of 5G C-V2X cross-border corridors to stimulate connected automotive applications, especially safety and navigation.
Ericsson has participated alongside Volvo, and they have just completed a successful joint handover of connected cars between two mobile 5G networks in different countries at the AstaZero test track in Sweden. This track is funded by the EU as part of an expanding initiative preparing for large-scale connected car trials along a 5G corridor between Metz in France, Merzig in Germany and Luxembourg. E
ricsson deployed a 5G mobile radio network at the track, while two Volvo cars received an HD map of the route ahead. This demonstrated use of 5G connectivity for updating the maps with real time information relating to traffic, road work, weather, or other factors.
Volvo contributed HD map software capturing information about lane boundaries, a requisite for safe autonomous operation as well as warning human drivers when they stray out of lane. This trial also demonstrated an enhancement where cars can contribute real time updates to the mapping system via a mobile edge cloud.
“Sharing an updated map with other cars is a latency-sensitive task and requires high network performance within and across multiple networks,” said Mikael Prytz, research director of Ericsson Area Networks. “During the test at the AstaZero track, we could tackle this challenge with promising results. We are excited to continue our cooperation with Volvo Cars to expand the network mobility of autonomous and connected cars.”