New guidelines forged by cross-industry collaboration are expected to ensure that devices running on the new LTE-U (Long Term Evolution in unlicensed spectrum) wireless protocol will not affect the quality and speed of existing Wi-Fi connections on shared unlicensed spectrum. But, concerns persist that LTE-U equipment may slow down, if not outright block, at least some Wi-Fi hotspots.
In order to deliver speedier and more advanced services, wireless carriers have clamored for a share of unlicensed spectrum on which Wi-Fi operates partially. The Federal Communications Commission (FCC) last year opened up spectrum for innovative uses enabled by fiber-fast wireless speeds and extremely low latency. FCC also encouraged industry to come up with unified guidelines on how best to share unlicensed spectrum between Wi-Fi networks and wireless communication companies.
After months of collaboration, the Wi-Fi Alliance and LTE-U communities in September 2016 unveiled the industry’s Coexistence Test Plan, which urged all LTE-U vendors and operators to use the test plan to ensure that their LTE-U devices and network deployments coexist fairly with Wi-Fi operating in the 5GHz band.
On Feb. 22, FCC's Office of Engineering and Technology authorized the first LTE-U devices in the 5GHz band. These certified devices have been tested to show they meet all of the FCC’s rules on preventing harmful interference to radio communications services and have been evaluated successfully under the Coexistence Test Plan.
"LTE-U allows wireless providers to deliver mobile data traffic using unlicensed spectrum while sharing the road, so to speak, with Wi-Fi," said FCC Chairman Ajit Pai. "This heralds a technical breakthrough in the many shared uses of this spectrum. This is a great deal for wireless consumers, too. It means they get to enjoy the best of both worlds: a more robust, seamless experience when their devices are using cellular networks and the continued enjoyment of Wi-Fi, one of the most creative uses of spectrum in history."
It may not be so seamless as expected, according to some critics.
“There could quite possibly be a significant disruption of Wi-Fi hotspots,” said Michael Calabrese, director of the wireless future project at New America Foundation’s Open Technology Institute, a public policy think tank, reports The Mercury News. He and others say LTE-U devices have been tested to interact only with relatively strong Wi-Fi signals, but not weaker ones, which LTE-U devices can effectively block.
Currently, wireless carriers are required to detect the presence of multiple Wi-Fi networks when transmitting signals over unlicensed spectrum. But the new LTE-U protocol reportedly does not have the same functionality as yet, since the industry is still working on it. Yet, Verizon and T-Mobile plans to roll-out LTE-U later this year.
“The technology has the potential to do harm to Wi-Fi,” Rob Alderfer, VP of technology policy at CableLabs, a research and development organization that serves the cable industry, told The Mercury News.
It remains to be seen whether these concerns are unfounded.
“The impact that LTE equipment may have depends highly on how broadly deployed LTE-U is and how broadly used it is,” he said. “To some extent we’ll have to wait and see how those deployments proceed,” Edgar Figueroa, CEO of the Wi-Fi Alliance, told the publication.