UPDATED: Wi-Fi Alliance presents coexistence guidelines; LTE-Forum revises specs to ensure LTE-U coexistence with Wi-Fi

While the Wi-Fi Alliance conducted its first workshop aimed at harmonizing Wi-Fi and LTE-U yesterday, the LTE-U Forum, based on feedback from the Wi-Fi community, has revised  its specifications for LTE-U to be "doubly sure" that LTE-U coexists with Wi-Fi and to provide a "smooth upgrade path" from LTE-U to LAA.

"These changes will also improve LTE-U performance," Qualcomm (NASDAQ:QCOM) said in a statement. Qualcomm has been one of the biggest proponents of LTE-U, along with operators Verizon (NYSE: VZ) and T-Mobile US (NYSE:TMUS).

The Wi-Fi Alliance this week presented its coexistence guidelines for LTE in unlicensed spectrum in what it described as an attempt to provide a common basis on which future Wi-Fi/LTE coexistence studies are conducted and to offer a foundation on which to build an unlicensed LTE test plan. Qualcomm and other members of the LTE-U Forum were invited to attend the full-day workshop in Palo Alto, Calif., yesterday.

Qualcomm told FierceWirelessTech that it was pleased to participate in the workshop and looks forward to continuing collaboration with the Wi Fi Alliance. "For the past two years, as Qualcomm and its partners developed LTE-U, we have had an ongoing dialogue with the Wi-Fi community to ensure that LTE-U does not cause any adverse impact on Wi-Fi," the company said. "We have a strong vested interest in ensuring that LTE-U coexists successfully with Wi-Fi in view of our own Wi-Fi business."

The Wi-Fi Alliance said its guidelines consider myriad use cases where Wi-Fi is used today, including video streaming, VoIP and dense and dynamic Wi-Fi environments. The guidelines focus on key performance indicators that matter for coexistence, expected real-world topologies of mixed Wi-Fi and LTE-U environments, and what the group calls realistic network loading scenarios.

Edgar Figueroa, president and CEO of the Wi-Fi Alliance, told FierceWirelessTech last month that the guidelines and testing may evolve based on industry input, and he reiterated that again this week. "Cooperation among a broad cross-section of industry provides the best opportunity to deliver a viable solution for fair coexistence," he said in a press release.

The guidelines mention two categories of Wi-Fi coexistence studies: Wi-Fi Baseline, where the performance of one or more Wi-Fi networks operating on the same channel is measured; and Wi-Fi and LTE Coexistence, where one or more Wi-Fi access points is replaced by an LTE device so that the impact of LTE on Wi-Fi performance can be assessed.

One of the objectives of the workshop was to bring all the stakeholders together and talk about how to resolve the concerns that people in the Wi-Fi industry have about LTE adversely impacting Wi-Fi users if introduced in unlicensed bands. Verizon, AT&T (NYSE: T), T-Mobile, as well as Amazon (NASDAQ: AMZN), Broadcom, Dell, Ericsson (NASDAQ: ERIC), Google (NASDAQ: GOOG), Intel, NTT and Gibson Brands were invited to participate in the workshop.  

"The Wi-Fi Alliance's efforts are a useful and important step to protect consumers' interests -- ensuring that Wi-Fi thrives while supporting innovation in unlicensed spectrum -- and we're heartened so many companies are participating," said Bill Maguire, director of WifiForward's Save our Wi-Fi Campaign, in a statement. "Wi-Fi and the other unlicensed technologies we depend on today did not happen by magic; they are the result of a collaborative multi-stakeholder, standards-setting process driven by the private sector, academics and independent engineers. The test plan discussed today shows that the process to develop LTE-U so far has lacked important aspects. We hope these guidelines will help all stakeholders to move back to the standards-setting process for the development of LTE-U."

Indeed, unlike Licensed Assisted Access (LAA), LTE-U was developed outside the standards bodies via the LTE-U Forum with Verizon, Qualcomm, Alcatel-Lucent (NYSE: ALU), Ericsson and Samsung as initial members. T-Mobile later threw its support toward the forum's efforts, and last month a coalition that includes many of the same in addition to AT&T, CTIA and the Competitive Carriers Association (CCA) launched Evolve, a coalition designed to promote the benefits of unlicensed spectrum and new technologies like LTE-U and LAA. 

CTIA has not had an opportunity to review the guidelines, but "we share the goal of demonstrating that consumers will benefit from LTE in unlicensed bands without harming unlicensed users," said Tom Sawanobori, SVP and CTO at CTIA, in a statement. "Any guidelines should reflect real-world use cases and recognize the extensive testing that has already been done that repeatedly shows Wi-Fi and LTE in the unlicensed bands coexist well together. As we have said all along, Wi-Fi remains an important offloading capability that wireless carriers need to meet Americans' mobile demands, and adding LTE in the unlicensed bands will only enhance user experience."

In August, Verizon, T-Mobile and Qualcomm were among a group expressing concerns that the Wi-Fi Alliance was trying to act like a "gatekeeper" by insisting that the FCC hold off certifying LTE-U equipment until the Wi-Fi Alliance could develop a coexistence test plan and complete its own coexistence evaluation program of LTE-U's impact on Wi-Fi. The LTE-U Forum released etiquette protocols and coexistence testing requirements in early March and has said it is working to educate the unlicensed community about the technology, providing detailed technical specifications and extensive coexistence test results.  

Before the workshop, the Wi-Fi Alliance sponsored research to gauge consumer attitudes about Wi-Fi. Not surprisingly, a large majority of employed adults said not having Wi-Fi access would impact their work productivity, with the largest impact taking place at home. Seventy-three percent of respondents said it's very/somewhat important to always have access to Wi-Fi in their daily life, while millennials (ages 18-24) are more likely to indicate this than any other group.

Kevin Robinson, vice president of marketing at the Wi-Fi Alliance, noted that a significant percentage of respondents 65 years and older shared that sentiment, indicating that Wi-Fi is a technology that spans generations. What was surprising is that according to the survey, which was conducted online in the United States by Harris Poll, 23 percent of Americans have heard of the term LTE-U. Robinson said some people probably keyed in on the "LTE" part of the question and not exactly the LTE-U in unlicensed spectrum that many in the industry are concerned about.

Both the Wi-Fi Alliance and the LTE-U Forum members have said they want to avoid regulatory intervention. The FCC in May took the somewhat unusual step of releasing a public notice seeking comment on LTE-U and LAA after it heard concerns about potential interference in unlicensed bands. Last month, some companies continued to urge the FCC to scrutinize LTE-U proponents.

This week's workshop was the only one on the calendar but more are expected to follow, likely after the holidays.

For more:
- see this release
- see these guidelines

Related articles:
Wi-Fi Alliance pushes ahead on coexistence guidelines for LTE-U
Google, Broadcom, Boingo, others push FCC to scrutinize LTE-U
AT&T, Verizon, T-Mobile throw support behind new LTE-U, LAA coalition
AT&T to trial LTE-U by early 2016
Sprint conspicuously absent from LTE-U debate

Article updated Nov. 5 to add additional comment about revised LTE-U specifications.

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