Why Extremely High-Power CBSDs Would Break the CBRS Ecosystem We Helped Build
By Jesse Caulfield, CEO, Key Bridge Wireless
April 15, 2026
Last week I congratulated my friend and longtime CBRS colleague Andy Clegg and the team at Valo Analytica on their new report, Negative Impacts of Higher-Power Operation on the Citizens Broadband Radio Service. The study, commissioned by Spectrum for the Future, is the most thorough technical analysis yet of what happens if the FCC allows Category C and Category D CBSDs, devices operating at 32 times and 320 times the power levels the band was engineered for.
As one of the original SAS administrators and the company that still runs one of the two production SASs serving the majority of the U.S. CBRS marketplace, we were proud to partner with Valo Analytica by supplying current, real-world registration data from more than 430,000 active CBSDs. That data powered their Shadow SAS simulations. So I have read every page with a very practical question in mind: Would these proposed power levels still let our SAS do the job it was designed to do?
The answer is a clear and sobering: No.
The CBRS band was deliberately built as the world’s first large-scale, three-tier, dynamic spectrum-sharing system. Its success rests on one foundational choice: low power, small-cell limits (Category A: 1 W, Category B: 50 W). Those limits were not an accident. They were chosen to maximize spatial reuse, enable dense coexistence, and let hundreds of different kinds of operators, not just the big national carriers, share the same 150 MHz of spectrum without stepping on each other or the incumbents.
The Valo report shows exactly what happens when you throw that design out the window.
Even if fewer than 2 percent of today’s CBSDs converted to high power, the ecosystem would suffer massive, permanent throughput collapse. Each new high-power device would create a PAL Protection Area (PPA) roughly twice (Cat C) to three times (Cat D) larger than today’s. Inside those expanded zones, co-channel GAA grants are automatically terminated. Outside them, hundreds of other grants are forced to throttle power to meet the aggregate interference limit.
Remember: 96 percent of all CBSDs in the United States today operate on GAA (either exclusively or to supplement their PAL holdings). Almost every enterprise private network, rural WISP, university campus, hospital system, and municipality relies on GAA spectrum. When the PPAs balloon, those users lose the spectrum they built their networks on.
Higher power would cause devastating effects in live CBRS networks. Manufacturing facilities using CBRS for autonomous robots, computer vision, logistics, and replacement of wired infrastructure would see roughly 1000 times degradation in throughput and latency. Office campus coverage would shrink dramatically, in the most extreme cases to an area smaller than the reach of a pair of wireless earbuds. Even protected PAL channels could suffer disruption from adjacent-channel interference, for which there is no SAS protection.
Airports relying on CBRS for security, surveillance, baggage handling, ramp monitoring, and Customs and Border Protection operations risk losing nearly one-third of their network capacity from a single high-power CBSD located almost anywhere in the surrounding metropolitan area. Network engineers have described such a loss as catastrophic.
Rural wireless internet service providers already experiencing interference from high-power 3.5 GHz operations across the Canadian border would see the problem spread nationwide. Interference reaches 80 to 200 km today and regularly knocks service offline for 50 percent or more of customers on affected towers. Widespread adoption of Category C or D power levels in the United States would create similar reliability problems on a much larger scale.
These examples are representative of the thousands of private LTE and 5G networks that have been built precisely because CBRS power limits allow localized, interference-managed operation.
Our SAS algorithms are standards-compliant and have protected incumbents flawlessly since commercial launch in 2020. But they were never designed to manage the interference footprints created by 15,849-watt devices. Adjacent-channel and blocking interference, which the current rules and SAS do not protect against between CBSDs, would explode. The delicate use-or-share balance that lets GAA and PAL coexist would collapse. The result: a band that once supported more than 1,000 operators and more than 430,000 base stations would quickly be dominated by a handful of macro-carrier deployments.
In short, the innovation band would stop being innovative.
Non-carrier operators, including manufacturers, airports, ports, utilities, schools, and rural ISPs, chose CBRS because it gave them affordable, licensed-quality spectrum without having to buy nationwide licenses or rely on carrier slices. High-power CBSDs would effectively price those users out of the band. Their business plans, hardware investments, and digital-transformation roadmaps would be stranded.
We at Key Bridge have spent eight years building and operating the systems that make CBRS work. We believe the band’s low-power DNA is the reason it has succeeded where other sharing experiments have not. Turning it into another macro-cellular band would destroy the very diversity and competition the FCC set out to create.
If you operate a CBRS network or simply value the private-wireless revolution that CBRS has enabled, now is the time to speak up. The FCC is still accepting comments in Proceeding 17-258 on these power-level proposals.
I encourage you to:
WISPA ran a similar letter-writing campaign late last year and 87 WISPs made their voices heard. Every additional submission matters.
The CBRS ecosystem has already delivered more innovation and more diverse users than anyone predicted in 2015. Let’s keep it that way.
—
Jesse Caulfield
CEO, Key Bridge Wireless
SAS Administrator since Day One of CBRS
jesse.caulfield@keybridgewireless.com
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