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The wireless industry has its eyes on the lower 3 GHz band, but it’s occupied by the DoD
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The DoD says sharing between federal and commercial systems is not feasible unless certain conditions are met
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Sharing between federal radar and mobile systems presents unique challenges, especially for airborne operations
The U.S. Department of Defense (DoD) this week finally released its September 2023 report on spectrum sharing, and let’s just say the DoD sure likes sharing a lot more than giving up spectrum.
But it only likes sharing if a boatload of conditions can be met.
The industry, primarily through lobbying groups like CTIA, sees the 3.1-3.45 GHz band as perfect for 5G. The problem is it’s currently occupied by the DoD. Ideally for industry, the DoD would vacate part of this band entirely, but according to the DoD, that would take too long and cost too much.
The long-awaited report was completed last year but a redacted version was just made public on Wednesday. It’s known as the Emerging Mid-Band Radar Spectrum Sharing (EMBRSS) feasibility assessment, and it’s 236 pages long.
Here’s the TL;DR version: The DoD uses this spectrum for critical homeland defense. Asking the DoD to vacate the 3.1-3.45 GHz band could set the DoD back several decades, cost hundreds of billions of dollars and take decades to actually do. Sharing “is not feasible” unless multiple conditions are met, including ensuring that the DoD retains primary residency in the band and that unique security requirements are implemented.
The EMBRSS notes that it’s the most complex evaluation on the feasibility of sharing that the DoD has undertaken to date. The department operates more than 120 different ground-based, shipborne and airborne radars in the band, so, you know, it’s kind of important.
Industry's response
Fierce checked in with a few folks to get their read on the EMBRSS report.
CTIA SVP Umair Javed released a statement Wednesday saying CTIA looks forward to “working with all stakeholders to identify ways to make more spectrum available for full-power, licensed commercial use domestically as soon as possible, while also supporting the needs of our military and national security.”
CTIA has been trying to steer everyone away from a sharing framework like the one in the 3.5 GHz Citizens Band Radio Service (CBRS) because it prefers fully licensed, higher power spectrum for wireless carriers. It’s also not a fan of dynamic spectrum sharing (DSS).
On the flip side, Spectrum for the Future (SFTF), whose members include cable companies like Comcast and Charter Communications, likes the CBRS model and wants to see more DSS. SFTF had asked for the unclassified findings of the EMBRSS report to be made public and applauded its release.
“The report confirms what experts have been saying all along – dynamic spectrum sharing in the lower 3 GHz band can unleash U.S. innovation and commercial 5G uses without weakening national security,” said SFTF spokesperson Tamara Smith in a statement.
Michael Calabrese, director of the Wireless Future Project at New America’s Open Technology Institute, is among those who would like to see more spectrum made available for use beyond traditional cellular.
As expected, the DoD report concludes that dynamic sharing with commercial use is possible, but not clearing large portions of the band at the sort of high power, very wide transmissions that mobile carriers prefer, he said.
“We remain optimistic that this spectrum will ultimately become available and very productive,” Calabrese said. “We are encouraging NTIA to build on DoD’s study and focus on refining how shared commercial use can coexist with military operations that cannot readily be moved to other bands.”
Old military radar
Richard Bennett, founder of High Tech Forum, said the core message of the EMBRSS report is “that the DoD has spent hundreds of millions of dollars on high-power military radar systems so fragile that they’re jammed by iPhones."
“The only sensible course of action is to make military radar more robust. It has to operate in a variety of environments, which should have been considered in every radar purchasing decision DoD has made for the last 15 years,” Bennett told Fierce via email.
“Had DoD supported NTIA’s 2010 ‘Plan and Timetable to Make Available 500 Megahertz of Spectrum for Wireless Broadband’ (proposing to use 3100-3500 MHz for mobile networks), the problem would have been solved by now,” he said, noting the similarity to the C-band where filters were added to the aviation industry's radio altimeters.
To be sure, the EMBRSS isn’t the last word on the matter. The DoD is expected to share more on the whole issue of spectrum sharing at an event on Monday, April 8, to unveil “a new initiative for collaborative spectrum study and experimentation.” The event is being held at CTIA headquarters in Washington, D.C., and will be aired via Zoom, so get the popcorn ready.
Fierce Wireless will be part of the new Fierce Network portal, starting April 8th. Bookmark the new site and get pumped!