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1 September 2022

WiFi in line for 5.9 GHz boost as Appeal Court backs FCC

The US Appeals Court has decided to uphold the Federal Communication Commission’s (FCC) reallocation of part of the 5.9 GHz band to unlicensed use, including WiFi, rather than keeping all of it for intelligent transportation systems (ITS).

This is notable on three levels. First, it gives succor to WiFi as the primary beneficiary of access to the lower 45 MHz of the 5.9 GHz band, bringing stability to the US market. The latest WiFi 6E, for the first time, extends into that band but it still requires regulators to allocate the requisite spectrum, as has happened increasingly around the world.

Secondly, the decision is a relief to the FCC itself, coming after a turbulent time for the regulator that saw it pitted against the Federal Aviation Agency (FAA) over the reallocation of another spectrum tranche, the C-band in the 3.7 GHz to 3.98 GHz range. The FAA had argued this risked dangerous interference with aviation altimeters operating at the higher but nearby frequency range of 4.2 GHz to 4.4 GHz. That and several other disputes had dented the FCC’s authority as the nation’s spectrum overlord, and the regulator was quick to assert this had been restored by the appeals court decision.

“The D.C. (District of Colombia) Circuit’s opinion is a victory for the public interest,” said Public Knowledge policy counsel Kathleen Burke. “Not only did the court reaffirm the FCC’s authority as the expert agency over spectrum decisions, but it also upheld the FCC’s correct call to stop bankrolling the auto industry’s speculation on Intelligent Transportation Services that were still in development after more than 20 years.”

Burke’s last point is rather disingenuous and leads to the third significant implication of the Appeal court decision, which is its impact on automotive connectivity and even the march towards autonomous driving. It is true that all 75 MHz of that 5.9 GHz band (5.85 GHz – 5.925 GHz) had been dedicated to ITS for 23 years after being set aside in 1999, primarily then for safety-related vehicle applications, with the intention that mobility would follow. But it is not really the fault of the automotive industry that this was ahead of its time and that the mobility related applications that would justify ringfencing of that spectrum never came along.

There was some effort under Obama’s presidency to bring on the WiFi-related Dedicated Short Range Communications (DSRC) for ITS, but that never came to full fruition and was blocked after Trump took over in 2016. That move worked out quite well as DSRC has been usurped by the more recently developed and in some respects technically superior Cellular-V2X technology, which has been exclusively adopted for advanced vehicular connectivity in China. C-V2X has also started to make inroads in Europe, which like the USA had initially looked set to mandate use of a WiFi-related variant.

In fact, three years ago in mid-2019, the European Commission backed down over plans to endorse the European WiFi automotive connectivity variant G-ITS (very similar to DSRC) after intense lobbying against this by the Global Mobile Suppliers Association (GSA), European Telecommunications Network Operators (ETNO), the 5G Automobile Association (5GAA), and some leading automotive makers.

Back in the USA, the FCC decided that the automotive industry could make do nicely with just the upper 30 MHz of that 5.9 GHz band and reallocated the rest to unlicensed use, essentially WiFi. In the same breath, the FCC imposed a requirement that after a transition period, ITS operations in the USA should migrate from DSRC to C-V2X.

This should have provided welcome clarity, although was initially opposed by those vendors and automotive makers that had invested significantly in DSRC. While some US car makers such as Ford had already made that switch, others such as GM were among the critics. And unanimously the USA automotive industry objects to the reallocation of that 45 MHz to WiFi, because no vested interest likes to surrender spectrum.

This led to the appeal, whose verdict dismayed ITS America and prompted the statement that this was a “blow to transportation safety for all Americans”.

The joint statement, by ITS America president and CEO Laura Chace and Jim Tymon, executive director of the American Association of State Highway and Transportation Officials, read: “At a time when roadway deaths are at an all-time high, our efforts to preserve the entire 75 MHz spectrum for connected vehicle safety solutions demonstrate the industry’s commitment to saving lives.”

It continues, “Transportation safety stakeholders are overwhelmingly unified in opposition to the FCC’s ruling. We are disappointed and frustrated that the FCC and the Court disregarded our collective expertise and feedback, ignoring the importance of transportation safety and ignoring the importance of using these technologies to stop the public health emergency on our nation’s roadways.”

More positively, the two bodies affirmed their determination to “ensure the remaining 30 MHz is free from dangerous interference and advances transportation safety”. It then called on the FCC to make more spectrum available elsewhere for advanced V2X communications expansion, again a more realistic hope.

Certainly, the 5GAA has argued consistently that 30 MHz of spectrum will not be enough to support its advanced use case, including autonomous driving that can be enabled by V2X using 5G NR. It conducted a study in 2020, finding that while 10 to 20 MHz would be enough to support basic safety services over LTE-V2X, a further 40 MHz at least would be needed for advanced driving services over 5G NR-V2X.

The cellular ITS communication takes place directly between vehicles (V2V) and with roadside infrastructure (V2I) over the sidelink PC5 interface, bypassing the public network and so not requiring access to a base station.

Even in Europe, which had already spurned C-V2X, most countries had allocated bands 5855-5875 MHz and 5875-5925 MHz, a total of 70 MHz, to ITS. The 5GAA went on to argue that global harmonization of bands would stimulate ITS and reduce costs.

“These conclusions clearly indicate that the entire 70-75 MHz of ITS spectrum in the 5.9 GHz band, as presently allocated in many regions and under consideration in other regions, is needed to support the basic safety and advanced use cases under consideration today,” 5GAA concluded. So, if the FCC did allocate spectrum to ITS elsewhere, it would not meet that desire for global harmonization.

In practice, the required capacity may become available for V2X in the US through spectrum sharing and improved efficiencies, but meanwhile 5GAA and the relevant bodies will continue lobbying for their cause.