The US FCC (Federal Communications Commission), in a recent meeting, has proposed the allocation of specific portions of the 5.9 GHz band for unlicensed device use and automotive communications technologies. As announced by FCC Chairman Ajit Pai, while the lower 45 MHz of the band will be allocated for unlicensed uses like Wi-Fi, the upper 20 MHz will be kept for new automotive communications technology, Cellular Vehicle to Everything (C-V2X).
Back in 1999, the FCC had allocated 75 MHz of spectrum in the 5.9 GHz band for a service called Dedicated Short-Range Communications. Commonly known as DSRC, this technology was intended to enable ubiquitous transportation and vehicle-related communications, but, the results haven’t matched that intent. The technology has evolved slowly, has not been widely deployed and now also faces stiff competition from a wave of new transportation communication technologies that have emerged in the recent years.
And thus, according to the Chairman, after 20 years of seeing these prime airwaves go largely unused, the time has come for the FCC to take a fresh look at the 5.9 GHz band. Specifically, the Proposed Rulemaking would re-purpose the lower 45 MHz (5.85-5.895 GHz) for unlicensed operations such as Wi-Fi, which FCC believes is ideally suited to meet the exploding Wi-Fi demands because of its location next to 5.725-5.850 GHz band that’s already allocated for unlicensed use. The rulemaking would also revise rules for the upper 20 MHz portion (5.905-5.925 GHz) of the 5.9 GHz band to authorize 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. The Commission will vote on this Notice of Proposed Rulemaking at its December 12 meeting.
According to FCC, DSRC’s lack of progress over the past 20 years becomes even starker when considered that 1999 also marked the birth of Wi-Fi. Since its launch, Wi-Fi has become a staple of everyday life and has become a foundational technology for the Internet of Things (IoT). But Wi-Fi’s popularity has raised a challenge for regulators: the need to make more spectrum available for unlicensed use. Indeed, to meet growing consumer demand, it’s estimated that the U.S. will need to allow unlicensed use of up to 1.6 GHz of new mid-band spectrum by 2025. The FCC has tried to answer this call.
Last October, the Commission began to explore opening up 1,200 MHz of spectrum in the 6 GHz band for different types of unlicensed uses. And now the FCC is proposing to permit unlicensed operations in the lower 45-MHz portion of the 5.9 GHz band. Thanks to its neighbor, this spectrum would punch above its weight. The adjacent 5.725 to 5.850 GHz band is currently available for unlicensed operations, making this 45 MHz sub-band ideally suited for unlicensed use. Having more contiguous spectrum here is essential for the larger channels needed to support innovative use cases.
The new proposal marks a departure from FCC’s recent exploration of allowing unlicensed devices to share the same spectrum with DSRC. 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, according to Pai.
FCC’s second proposal mentions the dedication of 30 MHz of spectrum in the 5.9 GHz band for Intelligence Transportation Systems. Automotive safety, according to Ajit Pai, has long been a priority for the FCC, with key-less entry, tire pressure monitors, anti-theft systems, and security services, being some of the solutions enabled by the Commission. Back in 2017, Chairman Ajit Pai had led an effort to allocate a large swath of contiguous spectrum in the 76-to-81 GHz band exclusively for vehicular radars. These radars have proved especially useful for emergency braking and adaptive cruise control.
And now one promising new technology that is gaining momentum in the automotive industry is C-V2X. It would use standard cellular protocols to provide direct communications between vehicles, and, as the name suggests, everything—including other vehicles on the road, infrastructure (like light poles), cyclists (like me), pedestrians, and road workers. C-V2X is also expected to support new, advanced applications as the world transitions to faster, more responsive 5G networks. And it is backed by major automakers like Ford, Audi, BMW, Daimler, and Tesla.
FCC thus proposes to authorize C-V2X operations in the upper 20 megahertz of the 5.9 GHz band. It hopes that this move will unlock new vehicle safety services, using less spectrum and on a much faster timeline than seen or realistically could be seen with a DSRC-focused policy. And although, the Commission has changed course and prioritized C-V2X technology, it will not close the door entirely on DSRC. It has thus proposed to seek public input on whether to allocate the remaining 10 MHz of spectrum in the 5.9 GHz band for DSRC or C-V2X. Advocates of each will be able to make their case.
According to Ajit Pai, this balanced approach has made FCC’s priorities clear: being committed to transportation safety. The Commission is focused on forward-looking spectrum policies to make US transportation networks safer and more efficient—including policies for the 5.9 GHz band.
The FCC Chairman believes the new proposal would do far more for both automotive safety and Wi-Fi, than the status quo. He believes, the policy, the FCC had in place since 1999 has not maximized the value of the 5.9 GHz band for the American people. And after four presidential administrations, eight FCC chairs, and 20 years, it’s long past time to turn the page. To move on from a failed strategy, look to the future, and score a major victory.
The Commission is set to vote on the Notice of Proposed Rulemaking at its upcoming December 12 meeting.
Click here to read FCC Chairman Ajit Pai's full statement.