Federal Communications Commission Chairman Ajit Pai issued a proposal Wednesday to dedicate slivers of the 5.9 gigahertz spectrum band to unlicensed Wi-Fi use and the use of Qualcomm's cellular vehicle-to-everything (C-V2X) protocol. The move is considered somewhat controversial since it goes against recommendations from the US Department of Transportation.
The Qualcomm technology promises to let vehicles wirelessly communicate with one another, and with traffic signals and other roadside gear, improving both functionality and safety. It's a harbinger of even greater capabilities when 5G networks become a widespread reality.
For more than two decades, the 75 megahertz of spectrum in the 5.9GHz band has been used exclusively for a transportation safety and communications technology known as Dedicated Short-Range Communications (DSRC). But Pai said in a speech Wednesday that the technology has been slow to evolve and isn't widely deployed.
"DSRC ... was intended to enable ubiquitous transportation and vehicle-related communications, but results haven't matched that intent." Pai said at a Washington, DC, event hosted by Citizens Against Government Waste, New America's Open Technology Institute and WifiForward. "Here we are, two decades later, and the situation can at best be described as 'promise unfulfilled.'"
In the meantime, Pai said, new transportation communication technologies have emerged, leaving many people wondering if "the valuable spectrum -- a public resource -- is really being put to its best use."
The FCC's proposal suggests allocating the lower 45MHz of the spectrum for unlicensed use, such as Wi-Fi. The proposal suggests dedicating 20MHz of the spectrum in that band to the C-V2X technology that's supported by the automobile industry. It then seeks comment on whether to earmark the remaining 10MHz of spectrum for the DSRC system or whether to allocate it to C-V2X technologies.
The FCC said in May that it would take a look at this band of spectrum and consider whether the DSRC systems could share the same spectrum with unlicensed users. But on Wednesday, Pai said further testing could take too long.
"Preliminary testing of a sharing regime showed some promise," Pai said during his speech. "But further testing would be needed to carry out a complex sharing regime, and more testing would mean this valuable spectrum would likely lie fallow for several years."
The US Department of Transportation has said the entire block of spectrum in the 5.9GHz band should remain allocated to the older DSRC technology. And a spokesman reiterated that sentiment following Pai's announcement.
"The Department of Transportation has clearly stated in testimony and correspondence that the 75 MHz allocated in the 5.9 GHz, what we call the 'Safety Band,' must be preserved for transportation safety purposes," the spokesman said in a statement. He added that the DoT "clearly foresees the need for protecting this spectrum allocation to enable the future of safe, highly automated surface transportation."
C-V2X and autonomous vehicles
The FCC's proposal is good news for companies like Qualcomm, which has helped develop the C-V2X technology, and car companies such as Ford, Audi, BMW, Daimler and Tesla, which plan to use the technology to provide vehicle-to-vehicle communications. C-V2X uses LTE networks and will eventually use 5G technology to provide reliable short and long-range transmissions of data between vehicles and infrastructure.
With 5G, the technology won't just allow cars to broadcast their location, speed and direction -- something some already do with today's 4G networks. In the future they'll also be able to negotiate taking turns at stop signs or merging into lanes. They'll be able to communicate with traffic signals to synchronize a trip with green lights. Vehicles could also talk with one another to create a platoon to squeeze more cars on the road and improve fuel economy.
Even though Pai is throwing his weight behind the C-V2X technology for the future, his proposal will seek comment and explore the option of maintaining some dedicated spectrum to support DSRC.
"Advocates of each will be able to make their case," Pai said.
The FCC is scheduled to vote on the proposal at its Dec. 12 meeting.