Wi-Fi, LTE worlds bump into each other in WIS panel debate

SAN MATEO, Calif.--Representing divergent views from the Wi-Fi and LTE industries, panelists from Ericsson (NASDAQ: ERIC), Qualcomm (NASDAQ:QCOM), Ruckus Wireless and CableLabs engaged in a lively debate at the Wi-Fi Innovation Summit (WIS) here Wednesday about LTE-U/LAA and its impact on Wi-Fi. Or lack thereof, depending on your viewpoint.

Nobody brought out the fisticuffs, but clearly, the Wi-Fi and LTE communities, generally speaking, have a ways to go when it comes to agreement on the impact and even the motives behind LTE-U. Discussions are ongoing in groups like the 3GPP and IEEE, but those conversations are not always so publicly accessible.

In the session titled "The Big LTE-U vs. Wi-Fi debate: Let's get to the bottom of this," moderator Claus Hetting of Hetting Consulting, chairman of the summit, attempted to do just that. He asked, for example, whether the industry needs a regulatory or other third party to determine or define what is fair use of unlicensed spectrum and what is not.

Representing the Wi-Fi community were Paul Petrus, chief wireless architect at Ruckus Wireless, and Alireza Babaei, lead wireless architect at CableLabs. Eric Parsons, head of mobile broadband at Ericsson, and Sanjeev Athalye, director of product management at Qualcomm, represented the LTE-U/LAA boosters. However, both Parsons and Athalye noted that their companies have stakes in both LTE and Wi-Fi, something that proved to be a bit of a bone of contention for some session attendees.

For the most part, the pre-standard LTE-U seemed to ruffle more feathers than LAA, which is being developed in the standards process.  

"As far as LAA is concerned, we think it's going in the right direction," Babaei said. However, "we believe we should avoid a hasty standard development," and consider extensive simulation scenarios. As far as LTE-U, "we have serious concerns. We think that … no technology in the unlicensed band should have control over the spectrum." Control is a privilege that mobile operators pay millions of dollars for in licensed spectrum, and the way LTE-U solution is currently designed, "we think it leads to domination of the spectrum."

As one of the leading providers of carrier-grade Wi-Fi access points, Ruckus is concerned about the proximity of LTE and Wi-Fi to one another and how that's implemented. That sparked a debate between Petrus and Athalye, one that's likely to continue outside the halls of conventions like this.

Hetting posed the question: What's in it for the Wi-Fi industry to partake in these discussions? After all, the industry is growing at a respectable clip and nobody, for example, is currently telling its stakeholders to change future technology releases so that LTE can work in the unlicensed spectrum.

Athalye clarified that it is unlicensed spectrum, not Wi-Fi spectrum, and both Qualcomm and Ericsson "want to protect each of the technologies." There also are members of IEEE and 3GPP who are Wi-Fi suppliers and they have been involved in healthy debate of the technical notes both online and off, he said.

By nature, Wi-Fi protocols are very polite, but LTE by nature is based on a schedule system, so they are very different, noted Babaei. Athalye said the scheduling nature of LTE makes it a better neighbor. "It's kind of an unfair comment to say that LTE is more aggressive or whatever the term was," Athalye said. Plus, given that mobile operators are now adopting Wi-Fi, it would be odd for them to try to crush Wi-Fi.

As for LWA, a member of the audience asked the panel: Why keep jumping over LWA, or LTE + Wi-Fi Link Aggregation? Some consider it a more palatable solution to the broader industry. What is the driving need to push toward a new standard? It's almost as if the vendors are giving a "trust me" type of answer by insisting they're looking out for both worlds, he added.

During the Q&A, Michael Marcus, director, Marcus Spectrum Solutions LLC, asked about FCC Chairman Tom Wheeler's statement last week saying the commission will open up a comment period on LTE-U sometime in May in the 3.5 GHz band, which may open a Pandora's box.

But while Qualcomm and Ericsson are trying to be responsible in their sharing mechanisms, "once you buy one of these devices from both Qualcomm and Ericsson, are the users absolutely forbidden" or physically impossible to reach inside there and change some of the sharing mechanisms in ways not exactly the way that Ericsson and Qualcomm anticipated?

In a lot of ways, the cellular carriers in the United States, which on the one hand say they want to use unlicensed spectrum, on the other hand have historically opposed new unlicensed spectrum. So there's a reason for the Wi-Fi community's concern in view of past CTIA membership statements, he said.

"I think part of the concern is, at least my concern is, that when the designers do this and they're making their best efforts, they should make sure their customers aren't able to undo some of the social sharing mechanisms that you are very carefully putting into it," Marcus commented.

Parsons said some things are not going to be changeable, but it's still up to the operator to deploy it in a reasonable way and make sure to follow the product guidelines for deployments.

Related articles:
LAA/LTE-U makes appearance at Brooklyn 5G summit
AT&T in no hurry to test and deploy LTE-Unlicensed
Verizon's LTE-U Forum completes LTE Unlicensed tests on way toward carrier's 2016 deployment in 5 GHz, 3.5 GHz
Qualcomm CTO thinks LTE-Unlicensed and Wi-Fi can coexist peacefully, targets mid-2016 for LTE-U phones

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