Editor's Corner—Wireless must get spectrum sharing right with 3.5 GHz

Nokia's Chris Stark, left, and Boingo CTO Derek Peterson at last month's Wireless Infrastructure Show 2017. Source: The Wireless Infrastructure Association
Colin Gibbs Editor's Corner

Spectrum sharing could help wireless carriers and others in the industry to maximize their use of airwaves as they transition to 5G. And the Citizens Broadband Radio Service (CBRS) in the 3.5 GHz band is positioned to be the canary in the spectrum-sharing coal mine.

So network operators and their partners need to get it right. And the clock is ticking.

The FCC voted more than a year ago to make 150 MHz of spectrum available for mobile broadband and other uses. The radio waves sit in the 3.5 GHz band that had previously been controlled by the U.S. Department of Defense (DoD).

Opportunities to innovate

The National Telecommunications and Information Administration (NTIA) several years ago identified the 3.5 GHz band as suitable for shared use between government and commercial interests as long as incumbents including the DoD and fixed satellite services were given protection. A three-tiered access framework was developed that includes an Incumbent Access tier, Priority Access tier and General Authorized access tier; those three levels will be coordinated through a dynamic Spectrum Access System (SAS).

The idea, of course, is to make the most of a finite resource—spectrum—to capitalize on 5G deployments as fully as possible.

“I think (5G spectrum) is going to (involve) combining licensed, unlicensed and shared,” said Boingo Chief Technology Officer Derek Peterson during a panel on spectrum and 5G that I moderated at the Wireless Infrastructure Show 2017 in Orlando, Florida, last month. “And what we’re going to see is more and more opportunities for shared. And I think that’s one of the reasons why all of us are interested in CBRS and the work going on there.

“It’s an opportunity for us to see how to innovate in shared spectrum, and to be able to push our opportunities and technologies that allow us to take advantage of that,” Peterson continued. “Because there’s a lot of spectrum out there today that’s available if we can find ways to use it more appropriately.”

Using new spectrum to pursue new models

That’s a very different model than the one U.S. carriers have built their businesses on. Operators traditionally buy spectrum licenses either at auction or directly through other license-holders, then deploy services on those airwaves as they see fit.

The wireless industry has done an impressive job of building a coalition in support of CBRS, however. Nokia and Qualcomm were among a mere half-dozen members that founded the CBRS Alliance last August, and its roster has quickly swollen to more than 50 members including all four major U.S. carriers as well as heavyweights such as American Tower, Crown Castle, Huawei and Samsung.

Perhaps it isn’t surprising, then, that the 3.5 GHz CBRS is moving rapidly toward a commercial rollout. It still isn’t clear when the first supporting handsets might come to market, as my colleague Monica Alleven documented last week, but the first services on those airwaves could be deployed by the end of the year.

“We expect that the spectrum access systems that are conditionally approved by the FCC should go through the formal testing this year and be ready for commercial use—the general authorized access of the three-tier sharing—late this year,” Federated Wireless CTO Kurt Schaubach during the round table discussion. “We’re sort of at the final stages of commercialization.”

An important transition or ‘a right dog’s breakfast?’

That widespread support only increases pressure on the wireless industry to develop models that will help drive the success of spectrum-sharing arrangements, however. U.S. wireless carriers have rarely been good at sharing anything, and the wireless industry will need to demonstrate some newfound flexibility and open-mindedness for spectrum sharing to be anything more than a high-minded waste of time.

“I think when it comes to sharing and what it can do to increase spectrum opportunities, I do think that CBRS in some respects holds the burden of proof in that we have to go out and make that one successful,” said Chris Stark, head of business development for Nokia North America. “We’re faced with an opportunity to show that we can actually as an industry come together and make something like CBRS happen, and demonstrate that sharing is a really valuable technique going forward.

“I do think CBRS has the burden of proof in some respects,” Stark concluded. “Conversely, I think if we make a right dog’s breakfast out of it”—a U.K. idiom describing a chaotic mess—“then people will be really worried about sharing from here on in.” - Colin | @colin_gibbs