A decision by the FCC suggests our autonomous future may be intrinsically linked to the future of 5G technology.
A recent decision by the U.S. Federal Communications Commission (FCC), which went largely unnoticed in the volatile political environment surrounding it at the time, is expected to have long-reaching effects on the future of advanced driver assist systems (ADAS) and autonomous vehicles.
It was a ruling on a highly technical matter that changed the allocation of radio-wave frequencies for Dedicated Short-Range Communications (DSRC) — hardly front-page news in the best of times.
What makes it significant is that it addresses the frequencies assigned exclusively for vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2X) communication — specifically the 5850-5925 MHz (5.9 GHz) “safety spectrum.”
V2V communication opens the door for the prevention of collisions, for example, by enabling communication between two vehicles approaching a blind intersection from different directions. Or by communicating slippery road conditions on the basis of ABS or anti-skid implementations.
Examples of V2X information transfer cited by Transport Canada include traffic light control, traffic monitoring, travellers’ alerts, automatic toll collection, traffic congestion detection, emergency vehicle traffic signal preemption and electronic inspection of trucks at roadside inspection facilities.
The FCC decision reduced the bandwidth of that safety communication spectrum by more than half (to 5895-5925 MHz), allocating it exclusively to cellular (C-V2X) technology. The rest of the original spectrum was turned over to unlicensed private usage such as Wi-Fi internet connectivity.
Given the limitations of existing 4G/LTE cellular technology, the FCC decision has effectively forced the adoption of forthcoming 5G (fifth generation) tech as the default platform for future vehicle safety connectivity.
It’s a move that has long been strongly opposed by the U.S. Department of Transportation (DOT). Additionally in April 2020, the Alliance for Automotive Innovation (AAI) proposed a five-year plan that would maintain the status quo and provide time for one or both the competing formats to prove themselves.
Opposition to the change centred largely on concerns about interference from adjacent frequencies, given the narrow bandwidth of the revised spectrum. Speaking to the matter at an SAE International government/industry meeting in 2020, John Kenney, Director and Senior Principal Researcher at Toyota InfoTech Labs, predicted that “interference from Wi-Fi could render the V2X spectrum useless.”
Many critics suggested that, at minimum, there had been insufficient study of the potential for cross-interference or overloading of the new C-V2X spectrum. A key argument against maintaining the original spectrum, however, was that only one automaker (Cadillac) had actually implemented DSRC capability since the bandwidth was allocated back in 1999, and then in fewer than 50,000 vehicles.
While the recent change of government in the U.S.A. has resulted in the rollback of multiple measures implemented in the previous regime, this FCC decision is widely expected to stand as it has strong support in the non-automotive business sector.
Canadian regulations on such matters tend to harmonize with those of our larger neighbour — all of which means the future of many anticipated vehicle connectivity features will be dependent on widespread access to 5G technology.
While the rollout of 5G is relatively advanced in some markets, such as China, it is in its early stages in Canada, and to a lesser degree the U.S. To date, it is largely limited to a few large urban centres and it is expected to take several years to become ubiquitous.
Beyond just a relatively long, staggered rollout, automakers face other challenges in adopting 5G C-V2X. One of those is the long development cycle of vehicles themselves, as well as their extended lifespan. Not only do vehicle systems have to function when they are new, but they must continue to do so typically for 10 to 15 years. That challenge becomes magnified given the comparatively rapid turnover rate of the electronic technologies themselves.
That issue may be partially addressed with the adoption of OTA (Over-The-Air) updates for software upgrades, but hardware upgrades pose a greater problem. So too does the very nature of vehicles, which are extremely mobile device-oriented, capable of moving quickly from areas of abundant cellular coverage to those with limited or zero coverage. Their connectivity can be instantly impaired by travel through urban canyons or parking in a deep underground lot.
To be effective, C-V2X safety systems must be able to hand off continuously from one cell to another, transfer to an alternative network if necessary, or even fall back to reliance on a satellite-based positioning system.
It’s a big challenge and there may prove to be a better way. For now, however, significant aspects of our ADAS/autonomous future seem to be intrinsically linked to the future of 5G technology.
