LTE-U coexistence harder than herding cats

A couple of recent announcements illustrate that achieving industry consensus over LTE-U makes herding cats looks like a walk in the park.

The Wi-Fi Alliance, a non-profit bankrolled by many (but by no means all) of the world’s biggest tech companies, has released its long-awaited LTE-U Coexistence Test Plan. This most cunning of plans aims to provide a definitive test to ensure LTE-U devices share unlicensed spectrum ‘fairly’.

LTE-U is contentious because it creates the prospect of LTE being transmitted over spectrum that’s currently being used by wifi. This is causing anxiety to companies with a major stake in wifi as they’re worried wifi signals will be degraded or even totally over-ridden by pushy LTE players. Conversely 5G zealots are keen to appropriate as much unlicensed spectrum as possible for their gigabit crusade.

“Delivering a cross-industry coexistence testing solution was an unprecedented and difficult task, and the outcome will help ensure the billions of people who rely on wifi every day will continue to benefit from the same great user experience they have enjoyed for more than 15 years,” said Edgar Figueroa, president and CEO of the Wi-Fi Alliance.

Early drafts of the test plan were met with almost universal derision but the final effort seems to have done a better job of reconciling the many competing claims on the spectrum.

“We applaud the Wi-Fi Alliance for developing a consensus-driven test plan that will ensure new LTE-U devices coexist fairly with the existing wifi networks and devices hundreds of millions of consumers already use and enjoy,” said unlicensed spectrum pressure group WifiForward in a statement.

“Measuring LTE-U devices for fair coexistence under the test plan is also crucial to protecting the major financial investments made by organizational wifi users from schools, hospitals and libraries to cities, governments and small businesses. Only by requiring LTE-U equipment vendors to test all proposed devices according to the clear, consistent and comprehensive standards of the test plan can consumers have confidence that their wifi will continue to work as designed.”

LTE-U is mainly a US issue right now, and WifiForward reckons the FCC will like the plan, which you can download in all its glory here. One company conspicuously absent from formal comment so far, however, is Qualcomm, which had previously been stridently critical of the Wi-Fi Alliance’s efforts.

“The latest version of the test plan released by the Wi-Fi Alliance lacks technical merit, is fundamentally biased against LTE-U, and rejects virtually all the input that Qualcomm provided for the last year, even on points that were not controversial,” said Dean Brenner, SVP of government affairs at Qualcomm in early August.

In a spooky coincidence, however, Liberty Global and non-profit cable consortium CableLabs announced on the very same day that they’re joining the MulteFire Alliance, another group created by Qualcomm to develop its MulteFire variant of LTE-U.

“We appreciate that the Alliance is committed to transparency and collaboration, given the importance of unlicensed spectrum to broadband access,” said Rob Alderfer, VP of technology policy at CableLabs. “As we move toward ever greater sharing of scarce spectrum resources, reliable coexistence across technologies is essential as we continue to innovate. It’s what we believe is the most critical aspect of the Alliance, and one that will be important as the industry moves toward 5G standards.”

“Operators in the cable industry are ideal partners in our effort to develop new wireless technology and we are pleased to have CableLabs and Liberty Global join us,” said Mazen Chmaytelli, MulteFire Alliance president. “The Alliance is open for broad, global participation, and since one of our goals is to drive our work into global standards, we are establishing liaisons with 3GPP, CBRS Alliance and IEEE to keep them apprised of our progress.”

The result is that we have at least two industry groups, each paying lip-service to the need for togetherness but with their own distinct ideas on how to go about it. It’s already a given that unlicensed spectrum will be a major feature of 5G but, by its very nature, reconciling the many competing needs of the various wireless stakeholders is a task of Byzantine complexity.