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 ask

Newsfeed

The 3.3-4.2 spectrum should be shared, not exclusively used by one company, concludes an important U.S. Defense Innovation Board report. If more wireless broadband is important, sharing is of course right because shared networks can yield far more

It does work! Verizon's mmWave tests over a gigabit in the real world. 
The $669 OnePlus 7 Pro outclasses the best Apples and probably the new Galaxy 10 or Huawei P30 Pro. Optical zoom, three cameras, liquid cooling, Qualcomm 855 and more.
Korea at 400,000 5G May 15. Chinese "pre-commercial" signing customers, 60,000-120,000 base stations in 2019, million+ remarkable soon. 
5G phones Huawei Mate 20, Samsung Galaxy 10, ZTE Nubia, LG V50, and OPPO are all on sale at China Unicom. All cost US$1,000 to 1,500 before subsidy. Xiaomi promises US$600.
Natural monopoly? Vodafone & Telecom Italia to share 5G, invite all other companies to join.
Huawei predicts 5G phones for US$200 in 2021, $300 even earlier
NY Times says "5G is dangerous" is a Russian plot. Really.
Althiostar raised US$114 million for a virtual RAN system in the cloud. Rakuten, Japan's new #4, is using it and invested.
Ireland is proposing a US$3 billion subsidy for rural fibre that will be much too expensive. Politics.
Telefonica Brazil has 9M FTTH homes passed and will add 6M more within two years. Adjusted for population, that's more than the U.S. The CEO publicly urged other carriers to raise prices together.
CableLabs and Cisco have developed Low Latency XHaul (LLX) with 5-15 ms latency for 5G backhaul,  U.S. cable is soon to come in very strong in wireless. Details 
Korea Telecom won 100,000 5G customers in the first month. SK & LG added 150,000 more. KT has 37,500 cells. planning 90% of the country by yearend. 
The Chinese giants expect 60,000 to 90,000 5G cells by the end of 2019.
China Telecom's Yang Xin warns, "Real large-scale deployment of operators' edge computing may be after 2021." Customers are hard to find.
Reliance Jio registered 97.5% 4G availability across India in Open Signal testing. Best in world.

More newsfeed

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Welcome On Oct 1, 2019 Verizon turned on the first $20B 5G mmWave network with extraordinary hopes. The actual early results have been dismal. Good engineers tell me that will change. Meanwhile, the hype is unreal. Time for reporting closer to the truth.

The estimates you hear about 5G costs are wildly exaggerated. Verizon is building the most advanced wireless network while reducing capex. Deutsche Telekom and Orange/France Telecom also confirm they won't raise capex.

Massive MIMO in either 4G or "5G" can increase capacity 3X to 7X, including putting 2.3 GHz to 4.2 GHz to use. Carrier Aggregation, 256 QAM, and other tools double and triple that. Verizon sees cost/bit dropping 40% per year.

Cisco & others see traffic growth slowing to 30%/year or less.  I infer overcapacity almost everywhere.  

Believe it or not, 80% of 5G (mid-band) for several years will be slower than good 4G, which is more developed.