America’s big four wireless service providers are enthusiastic about the prospect of delivering data over unlicensed frequencies via LTE-U, but they’re playing their cards very close to their chests when it comes to specific plans.

LTE-U, which is a wireless protocol designed to let carriers use their LTE signals over the same unlicensed frequencies as Wi-Fi, is a controversial technology. Advocates, which include the wireless carriers, insist that coexistence features built into the standard will allow it to use the same airwaves as Wi-Fi without interference. Critics say that independent testing shows that LTE-U could drown out Wi-Fi signals when the two conflict.

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VERIZON ON LTE-U

Rumored deployments of LTE-U have been pegged to this calendar year, but only Verizon was willing to state on the record that it is, in fact, planning to deploy LTE-U in 2016. The company’s assistant vice president for federal regulatory affairs, Patrick Walsh, told Network World that Verizon was planning a limited trial deployment late this year.

“The initial deployment will be very limited, the only product that we have right now is an in-building enterprise solution,” he said, declining to say where that initial deployment might take place.

However, Walsh added, Verizon feels that the long-term promise of LTE-U technology is substantial, and that concerns about interference with existing Wi-Fi are groundless.

“LTE is a better neighbor to Wi-Fi than Wi-Fi is to itself,” he said. “We see [LTE] as a great opportunity to help improve the overall mobile broadband experience for our customers by providing better coverage and faster download speeds.”

It all boils down to a network that sucks or a network that doesn’t suck.

Sathya Atreyam, research manager, worldwide wireless network infrastructure, IDC

Verizon, along with AT&T and T-Mobile, is a member of the Evolve Coalition, an industry group advocating the benefits of LTE-U. (Other members include Ericsson and Qualcomm, the companies most responsible for the development of the LTE-U standard.)

SPRINT SEES LTE-U OPPORTUNITY

Even though it’s not a member of the Evolve Coalition, Sprint echoed much of the party line when contacted, with corporate communications Senior Manager Adrienne Norton saying that LTE-U represents “a great opportunity,” and that it was “complementary to our network strategy.”

Still, Norton would not confirm or deny whether Sprint had plans to deploy LTE-U, and she came closest to acknowledging that opponents of the technology might have a point.

“We see no reason to rush forward with LTE-U amid uncertainty and acrimony over basic technical facts,” Norton said. “Our technology teams are evaluating both LTE-U and LAA, and while the use of unlicensed spectrum is on Sprint’s long-term road map, our rich 2.5GHz spectrum position gives us the highest capacity network today and well into the future.”

AT&T AND T-MOBILE STAY HUSH-HUSH

AT&T was also relatively unforthcoming. Global Media Relations Director Jim Greer said the company is evaluating unlicensed technology, and testing new wireless capabilities in its labs, but wouldn’t directly confirm AT&T’s LTE-U plans, and declined to give a definitive answer as to whether AT&T believed LTE-U as currently constituted would interfere with Wi-Fi.

T-Mobile did not respond to requests for comment.

That’s not a big surprise, according to wireless expert Craig Mathias. Details about potential LTE-U deployments are competitively valuable, so it’s unlikely that the carriers would want to let them slip.

“The carriers will not tip their hand until all of the cards are dealt,” he said. “And we're still at least a year away from that.”

Mathias (who has written for Network World in the past) also said that issues of interference haven’t yet been resolved. It’s another factor delaying LTE-U deployments – whether the carriers admit it or not.

“Can you imagine the negative press if LTE-U clobbers Wi-Fi?” he asked.

Moreover, IDC research manager Sathya Atreyam said the carriers may be less sanguine about LTE-U’s friendliness with Wi-Fi than they’re saying publicly. It’s a question of hanging on to subscribers, particularly for the current front-runners, Verizon and AT&T.

“They don’t want this LTE-U vs. Wi-Fi debate to trigger more churn,” he said. “Because everything depends on the quality of experience – it all boils down to a network that sucks or a network that doesn’t suck.”