More WiFi Spectrum

There is more WiFi spectrum on the way due to the US Court of Appeals for the District of Columbia that rejected a legal challenge from the Intelligent Transportation Society of America and the American Association of State Highway and Transportation Officials that had asked to vacate the FCC’s 2020 order to repurpose some of the spectrum that had been reserved for smart cars.

The spectrum is called the 5.9 GHz band and sits between 5.85 GHz and 5.925 GHz. The FCC had decided to allocate the lowest 45 MHz of spectrum to WiFi while allowing the upper 30 MHz to remain with the auto industry.

The process will now begin to make the transition to WiFi. The FCC had originally given the auto industry a year to vacate the lower 45 MHz of spectrum. The FCC is likely going to have to set a new timeline to mandate the transition. The FCC also needs to rule on a waiver from the auto industry to redeploy technology using the Cellular Vehicle-to-Everything (C-V2X) technology from the lower to the higher frequency band. This is the technology that most of the industry is using for testing and deploying self-driving vehicles.

The lower 45 MHz of the new spectrum sits adjacent to the existing WiFi 5.8 GHz spectrum. Combining the new spectrum with the existing band is a boon to WISPs, which now get a larger uninterrupted swath of spectrum for point-to-multipoint broadband deployment. During the early stage of the pandemic, the FCC gave multiple WISPs the ability to use the 5.9 GHz spectrum on a trial basis for 60 days, and many of them have been regularly renewing that temporary licenses since then.

When the FCC announced the resolution of the lawsuit, the agency issued a press release discussing the benefits touted by WISPs for using the new spectrum. Some of them claimed to see between a 40% and 75% increase in throughput bandwidth. This was mostly due to less congestion on this spectrum, which is rarely used. There was little or no interference during the last year. The spectrum also provided a clear path for wireless backhaul between towers. Of course, once this is made available to all WISPs, it’s likely that much of this benefit will disappear as everybody starts vying to use the new spectrum. But it is an increase in bandwidth potential, and that has to mean higher quality wireless signals.

This spectrum will also be available for home WiFi. However, it takes a lot longer for the home WiFi industry to respond to new spectrum. It means upgrading home WiFi routers but also adding the capability to use the spectrum to the many devices in our homes and offices that use WiFi. Everything I’m reading says that we are still years away from seeing widespread use of the 6 GHz WiFi spectrum, and this new bandwidth will likely be rolled out at the same time.

This was an interesting lawsuit for several reasons. First, the entities filing the court suit challenged the FCC’s ability to change the use of spectrum in this manner. The court decision made it clear that the FCC is fully in the driver’s seat in terms of spectrum allocation.

This was also a battle between two large industries. The FCC originally assigned this spectrum to the auto industry twenty years ago. But the industry was slow to adopt any real-world uses of the spectrum, and it largely sat idle, except for experimental test beds. There is finally some movement toward deploying self-driving cars and trucks in ways that uses the spectrum. But even now, there is still a lot of disagreement about the best technology to use for self-driving vehicles. Some favor the smart road that uses spectrum to communicate with vehicles, while the majority opinion seems to favor standalone smart-driving technology in each vehicle.

Between this order and the 6 GHz spectrum, the FCC has come down solidly in favor of having sufficient WiFi spectrum going into the future. It’s clear that the existing bands of WiFi are already heavily overloaded in some settings, and the WiFi industry has been successful in getting WiFi included in huge numbers of new devices. I have an idea that we’ll look back twenty years from now and say that these new WiFi spectrum bands are not enough and that we’ll need even more. But this is a good downpayment to make sure that WiFi remains vigorous.

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