FCC's Wheeler: Engineers Should Lead on LTE-U Standards

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By Lydia Beyoud

Sept. 9 — The FCC wants to see engineering standards bodies find a solution to enable mobile technology and Wi-Fi users resolve the interference issues raised by the planned deployment of LTE-Unlicensed (LTE-U) technology, Chairman Tom Wheeler said Sept. 9.

As licensed and unlicensed users increasingly look to spectrum sharing or coexistence mechanisms to keep up with demand, the Federal Communications Commission will be faced with new policy challenges in helping maximize the best use of finite spectrum resources, Wheeler said at CTIA—The Wireless Association's Super Mobility conference in Las Vegas. The rift between different interests over LTE-U underscores that challenge.

The issue has pitted wireless companies against tech companies and others. The wireless industry, including Qualcomm Inc., T-Mobile US Inc. and Verizon Communications Inc., is working to bring different varieties of LTE-U technology to market by 2016 to help augment spectrum capacity. The companies and their trade association, CTIA, have promised that even pre-standard LTE-U deployment won't interfere with unlicensed users. They are resisting calls for any sort of FCC involvement.

However, cable companies backing Wi-Fi technology, as well as Google Inc., Microsoft Corp. and public interest groups have raised numerous concerns that the technology could be used to dominate unlicensed airwaves by introducing interference or latency in Wi-Fi connections.

Allowing standards bodies incorporating the views of all stakeholders to find a technical solution to interference and coexistence issues would be “far preferable” to the FCC dictating a solution, Wheeler said. “I think this is up to them more than up to us,” he said.

Julius Knapp, bureau chief of the FCC's Office of Engineering and Technology, sent a letter Aug. 5 to the LTE-U Forum, led by Qualcomm, seeking answers to several technical questions and about the group's interest in deploying LTE-U technology in the U.S. before all the interference issues are resolved through testing.

The LTE-U forum and T-Mobile jointly responded to that letter with a Sept. 9 filing that LTE-U technologies will use three different “etiquette” protocols to sense whether information is being transmitted on a Wi-Fi network before transmitting itself, similar to Wi-Fi's “listen-before-talk” protocol, along with other protocols.

“The technical work that the LTE-U Forum has done to enable successful coexistence between LTE-U and Wi-Fi is also informing and advancing the coexistence work” on Licensed Assisted Access (LAA), another form of LTE-U used primarily in Europe and Japan, and Qualcomm's proprietary standalone LTE in unlicensed known as MuLTEfire, the group said.

“I was encouraged that Chairman Wheeler acknowledged the potential benefits of LTE-U technology for consumers,” Dean Brenner, Qualcomm's senior vice president of government affairs told Bloomberg BNA. “All the companies involved in LTE-U are also strong supporters of Wi-Fi and have every incentive to ensure that LTE-U has no adverse impact on Wi-Fi,” Brenner said.

Tech and cable companies are sounding a conciliatory note.

“While no single user speaks for unlicensed spectrum, numerous users of unlicensed spectrum want to work with Qualcomm and carriers to ensure that technologies like Wi-Fi and LTE-U can co-exist so that LTE-U doesn't crowd out Wi-Fi,” said WifiForward, a coalition of groups including the American Library Association, Best Buy Co. Inc., Google , Microsoft and major cable companies such as Comcast Corp. and Charter Communications Inc., in an e-mailed statement.

“We agree with Chairman Wheeler: the standards-setting organizations should work cooperatively to reach a solution that works for everyone,” the group said in its statement.

The National Cable and Telecommunications Association (NCTA) said it intends to work with other stakeholders on improving LAA standardization but has voiced concern that LTE-U “does not meet even the minimal coexistence standards being advanced for LAA,” according to an FCC filing posted Sept. 9. American consumers could miss out on the benefits of a global LAA standard if wireless carriers continue to pursue pre-standardized LTE-U deployment, NCTA said, according to the filing. The cable trade group called for Wi-Fi like coexistence features to be applied equally to all variants of LTE-U.

Certification Process

In his letter, Knapp said any applications for certifying LTE-U equipment will be reviewed by the agency and subject to a full technical description of how the devices will operate.

“We are confident that at the end of the day, any fair person will conclude that LTE-U will not have any adverse impact on Wi-Fi,” said Brenner. “In developing LTE-U, we have collaborated broadly with the Wi-Fi community (of which we are part) in groups, individually, and via associations, and we plan to continue doing that to address questions, ease concerns, and resolve issues,” he said.

To contact the reporter on this story: Lydia Beyoud in Washington at lbeyoud@bna.com

To contact the editor responsible for this story: Heather Rothman at hrothman@bna.com

Text of Knapp's letter is at http://apps.fcc.gov/ecfs/document/view?id=60001120730.

Text of the LTE-U Forum's response is at http://src.bna.com/g5.

Text of NCTA's filing is at http://apps.fcc.gov/ecfs/document/view?id=60001323480.