It's currently used for military radar but NTIA is looking to make it available. The work around CBRS is proving that sharing spectrum can work, even if the military is an interested party. Before using the band, you would have to check with a database to see whether it isn't reserved. 

The classic example is naval shipboard radars. A user in Iowa is unlikely to cause interference. Research in the 3550 CBRS band finds most of the U.S. is not in use. It would be natural to simply expand CBRS down another 100 MHz. 

The primary source is a blog by David Redl at NTIA, below.

Putting more spectrum to use is always a good thing, except for the telcos who want to kill competition. AT&T led the call for more spectrum, which became the primary recommendation of the Broadband Plan. T assumed they and Verizon would claim most new spectrum and raised a large ruckus when the rules had some limits. T-Mobile, which actually might face a spectrum issue in a few years, is carrying on the battle.

Blair Levin at the plan was very hopeful that freeing up spectrum would result in some badly needed competition. Eight years later, it hasn't happened. Even if the spectrum were free, nearly no one is willing to fund a new network. It costs >$5B to build a network across the U.S. and nearly as much to carry it to breakeven. Until recently, only AT&T & Verizon were profitable. Sprint remains so unprofitable that Craig Moffett believes they have no path to sustainability. 

The prospects for another mobile network are dismal, except for the cable companies. They already have a huge customer base as well as lots of fiber & local facilities. They have turned on a second SSID in ?10M cable modems for more bandwidth. Comcast is moving slowly, reselling Verizon. Charter has announced. Both have huge efforts going to be ready to launch their own networks in a few years and are very visible in technical meetings. There is no doubt about the plans. 

The question is whether a phone company will offer the cablecos such a good deal it would be smarter to buy rather than make. That would be a natural move for Sprint or T-Mobile if they don't merge. Hard to game this one out.

This is good work by Redl, although I wish he hadn't included the DC untruth that the U.S. is ahead in 4G. That may have been true in 2009, but five years ago many started passing the U.S. We are now something like 39th in the world in speeds, behind countries like Bulgaria & Albania. We don't have a single company able to deliver a 4G (or 5G) network, France is less than half the price & China has more than four times as many subscribers.

We will be ahead in millimeter wave by this time next year because Verizon is the only company in the Western world with a clear business case. China Telecom is doing 2M base stations of sub-6 GHz, not millimeter wave.

NTIA Identifies 3450-3550 MHz for Study as Potential Band for Wireless Broadband Use

 
February 26, 2018 by David J. Redl, Assistant Secretary for Communications and Information and NTIA Administrator
 

Americans rely on broadband Internet access to stay connected, to conduct business, to interact with the government, and for entertainment. Our nation’s broadband needs are increasingly wireless. Whether it’s 5G wireless technologies that promise to deliver dramatic increases in wireless broadband speeds and bandwidth, or the unlicensed technologies we place in our homes, businesses, and communities, wireless broadband technologies are paving the way for transformative changes that will improve health care, advance manufacturing and benefit public safety.

America is the world’s leader in Wi-Fi and 4G LTE and we have claimed an early lead in bringing 5G to reality. It’s essential to American competitiveness that we maintain our leadership in all of these areas. This is a Commerce Department priority under Secretary Wilbur Ross, who understands that to fully realize this potential, we need more spectrum to support broadband data access across the electromagnetic spectrum. 

To meet this growing need, NTIA, in coordination with the Department of Defense (DOD) and other federal agencies, has identified 100 megahertz of spectrum for potential repurposing to spur commercial wireless innovation. This spectrum, the 3450-3550 MHz band, is in the mid-frequency range and could be a key asset in our nation’s broadband spectrum inventory.    

In the United States, military radar systems currently operate in the 3450-3550 MHz band. DOD plans to submit a proposal under the Spectrum Pipeline Act to carry out a comprehensive radio-frequency engineering study to determine the potential for introducing advanced wireless services in this band without harming critical government operations. We hope the result of this hard work will be a “win-win,” enabling the continuing growth of the U.S. wireless industry while protecting radars that are vital for national security.

The Federal Communications Commission (FCC), in coordination with NTIA and DOD, has already approved rules for the adjacent 3550-3700 MHz band for its planned Citizens Broadband Radio Service (CBRS). And the United States is joined by regulators in Europe and elsewhere in looking to include mid-frequency spectrum for commercial use. The potential for international spectrum harmonization could lead to the creation of a global market for equipment that includes the 3450-3550 MHz band, and could help bring services to market quicker, and at lower prices for consumers.

The decision to study the 3450-3550 MHz band is part of an ongoing effort across the U.S. government to support deployment of wireless broadband and foster American leadership in 5G. Collectively, NTIA, the FCC and the federal agencies are making great strides across low-, mid- and high-frequency spectrum, including innovative sharing approaches in the AWS-3 and the CBRS bands.

Ensuring sufficient spectrum will be available for advanced services is a goal shared across government and industry, and NTIA will work with our partners to do everything we can to bring our nation’s 5G future to fruition.

dave askJuly 2018 Verizon's $20B 5G build is starting to add customers in 2018. Gigabit LTE & Massive MIMO became real in 2017. Verizon U.S. 5G mmWave 5G is firm. Almost all the other "5G" is mid-band, 70%-90% slower + hype. Europe is mostly pr. The term 5G has been bastardized, unfortunately.

Being a reporter is a great job for a geek. I'm not an engineer but I've learned from some of the best, including the primary inventors of DSL, cable modems, MIMO, Massive MIMO, and now 5G mmWave. Since 1999, I've done my best to get closer to the truth about broadband.

Send questions and news to Dave Burstein, Editor. I always want to hear from you, especially if you catch a mistake.