What’s LTE Over WiFi? How Could It Speed Up Your Phone?

Source: iStock

Source: iStock

Your data speed and coverage could soon improve thanks to an innovation called LTE over WiFi. The technology would enable carriers to expand traffic to unlicensed spectrum, specifically the 5GHz WiFi band that’s used by new routers, tablets, and even recent smartphones. Here’s what you need to know about the technology, and about how controversy over potential interference with WiFi devices is threatening to delay its deployment.

While carriers usually rely only on airwaves to which they have exclusive licenses, a new system called LTE-Unlicensed would enable carriers to share spectrum with WiFi devices on the unlicensed 5GHz band. But Jon Brodkin reports for Ars Technica that the plan has sparked concerns about interference with existing WiFi networks, and everyone from wireless carriers to cable companies to a WiFi industry trade group is getting involved.

Verizon has said that it plans to deploy LTE-U in 5GHz in 2016, and before the controversy over potential interference arose, T-Mobile was expected to use the technology by the end of 2015. Using 5GHz will enable wireless networks to boost data speeds over short distances, without requiring users to log in to separate WiFi networks. In the latest development, Verizon, T-Mobile, Alcatel-Lucent, Ericsson, and Qualcomm sent a letter to the Federal Communications Commission to express their opposition to a WiFi Alliance proposal that would slow the process of deploying LTE-U to carriers’ networks.

The WiFi Alliance is an industry trade group that certifies equipment to ensure that it doesn’t interfere with other certified equipment operating in the same frequencies. The group asked the FCC to avoid authorizing any LTE-U equipment until the WiFi Alliance is able to conduct its own tests, using new interference testing guidelines that the Alliance is still in the process of developing.

As Ars Technica notes, the WiFi Alliance has an extensive list of members that covers “pretty much the entire technology industry, including the five companies opposing its request.” In their letter to the FCC (PDF), the companies wrote that as members of the WiFi Alliance, they are “interested in extending the benefits of LTE on unlicensed spectrum.” But they urge the FCC to reject the alliance’s “unprecedented” request, which would have the effect of “allowing an organization that certifies interoperability for one particular technology to become the gatekeeper for another technology to use unlicensed spectrum.”

Cable and Internet providers have also gotten involved, since many have set up networks of WiFi hotspots around the country. The National Cable & Telecommunications Association (NCTA), which represents Comcast, among other cable companies, has raised concerns that LTE-U and a related technology called Licensed Assisted Access (LAA) would decrease the performance of WiFi networks. The NCTA says that cable industry research has shown that in specific circumstances, LAA  could lower the WiFi transmission success rate “by 77 percent with fifteen nearby consumer Wi-Fi devices, and by 88 percent with twenty nearby consumer devices.” T-Mobile countered, arguing that claims were exaggerated, and “based on testing with parameters set at extremes that do not represent realistic deployments or do not reflect actual LTE-U specifications.”

The FCC has yet to make a final decision, and noted in a recent filing that there are “potentially four different types” of LTE-U technology being developed, counting separate efforts by industry groups and a proprietary version being developed by Qualcomm. Any new equipment will need to go through the commission’s standard process for dealing with new technology.

As Mark Sullivan reported for VentureBeat earlier this year, using unlicensed spectrum holds promise as a way “to scale up wireless capacity and speeds in a world where licensed spectrum is limited and where demand for mobile Internet service continues to shoot upward.” It presents an interesting situation for carriers, who are accustomed to spending billions to buy licensed spectrum. And it could give rise to new competitors, like new types of wireless services launched by startups, and create pressure for decreasing prices. But carriers are going along with LTE-U because they want to run LTE service in unlicensed spectrum to improve performance during “surge” periods, when traffic levels are high.

Sullivan explains that “the genie appears to be well out of the bottle” despite early concerns about possible interference. “LTE service has a way of pushing other wireless services out of the way when moving in the same spectrum band,” Sullivan reports, noting that one telecom exec told his publication that LTE is “a bit of a bull in a china shop” while “Wi-Fi is known as a ‘polite service’ and can be easily pushed out of the way.”  But Sullivan reports that new software has been developed “to make the various signals play nice within a shared spectrum band,” paving the way for LTE-U to be deployed.

Google is one party that has expressed reservations about how LTE over unlicensed spectrum would impact WiFi services. In a recent post to its public policy blog, the company suggested that carriers could use newly-available, now underused spectrum in the 3.5GHz band, and leave the 5GHz band alone. The post notes, “The entire wireless ecosystem should be concerned about allowing one innovation to block others — past and future. The best way to stimulate innovation without regulatory intervention is for the industry to maximize use of all available spectrum and develop workable coexistence and coordination mechanisms that encourage widespread access to unlicensed spectrum.”

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