FCC looks to dedicate 5.9 GHz for Wi-Fi, C-V2X use

In a somewhat controversial move at odds with the wishes of the U.S. Department of Transportation, FCC Chairman Ajit Pai on Wednesday proposed dedicating respective portions of the 5.9 GHz band for unlicensed device use and C-V2X technologies.

Since 1999, the 75 megahertz of spectrum in the 5.9 GHz band has been allocated exclusively for Dedicated Short-Range Communications (DSRC) systems for transportation safety and vehicle communications, but Pai said (PDF) Wednesday that the technology, slow moving to evolve and not widely deployed, is best described as “promise unfulfilled.”

RELATED: FCC Chairman Pai: Time to take a fresh look at the 5.9 GHz band

Specifically, the Notice of Proposed Rulemaking would repurpose the lower 45 megahertz (5.85-5.895 GHz) for unlicensed operations such as Wi-Fi, which Pai said is ideally suited to meet exploding Wi-Fi demands because of its location next to 5.725-5.850 GHz band that’s already allocated for unlicensed use. The NPRM would also revise rules for the upper 20 MHz portion (5.905-5.925 GHz) of the 5.9 GHz band to authorize Cellular Vehicle to Everything (C-V2X) technologies that are supported by the automobile industry.

For the remaining 10 MHz, the FCC would seek comment on whether to retain the current designation for DSRC systems or allocate it to C-V2X technologies.  

In May the FCC decided to take a fresh look at the 5.9 GHz band, but the new proposal is a departure from the agency’s efforts and testing to evaluate possible sharing between unlicensed devices and DSRC systems on the same spectrum.

“Preliminary testing of a sharing regime showed some promise, 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,” said Pai during remarks at the National Union Building.

The U.S. Department of Transportation, however, still believes the full 75 MHz of the 5.9 GHz band needs to remain dedicated for vehicle safety communications.

RELATED: Truckers say 5.9 GHz DSRC spectrum is critical for V2V

A DoT spokesperson provided the following statement with regard to Pai’s new proposal: “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 Department’s multimodal guidance document, Preparing for the Future of Transportation: Automated Vehicles 3.0 (AV 3.0) clearly foresees the need for protecting this spectrum allocation to enable the future of safe, highly automated surface transportation.  This continues to be the Department’s position on the 5.9 GHz band. We look forward to working with the FCC, the National Telecommunications and Information Administration (NTIA), and over 30 Federal partner agencies to deploy solutions that enable breakthrough safety on America’s roadways.”

Companies like Qualcomm have been developing C-V2X technologies and supported earlier waiver requests by the 5G Automotive Association (5GAA), as did Nokia and Samsung, for permission to deploy the technology in the upper portions of the band currently designated to DSRC.  

Dean Brenner, senior vice president of spectrum strategy and technology at Qualcomm praised the latest move on 5.9 GHz. 

"Qualcomm is very pleased that FCC Chairman Pai is proposing to allocate the upper 20 MHz of 5.9 GHz for C-V2X, as the 5G Auto Association proposed last year," said Brenner in a statement. "This visionary FCC proposal will enable us to bring the tremendous, unmatched safety benefits from C-V2X to US drivers, passengers, and pedestrians.  We look forward to working with the FCC and all other stakeholders to get C-V2X on the air as quickly and broadly as possible.”

The FCC is hoping the new proposal will balance desires of public agencies like the DoT with industry interests such as automotive companies supporting C-V2X technologies including Ford, Audi, BMW, Daimler and Tesla.

It should be noted that C-V2X is not compatible with DSRC, according to Pai, who said he’s chosen to change course and prioritize C-V2X instead in the hopes “that this move will unlock new vehicle safety services, using less spectrum and on a much faster timeline than we have seen or realistically could see with a DSRC-focused policy.”

The commission will vote on the item at its upcoming Dec. 12 open meeting.