LTE was designed to run on frequencies licensed by mobile operators for their exclusive use. But an emerging technology called LTE-Unlicensed allows the cellular system to supplement those frequencies with unlicensed spectrum that's shared with systems like Bluetooth and Wi-Fi. This gives the carriers additional spectrum that they don't have to pay for in an auction.
Wireless providers including T-Mobile USA, Verizon Wireless and SK Telecom are already looking into LTE-Unlicensed. But some Wi-Fi proponents, including Google and the Wi-Fi Alliance, warn that LTE transmissions in the 5GHz unlicensed band might crowd out Wi-Fi users. An emerging variant of the technology, called LAA (Licensed-Assisted Access) is designed to ease those concerns and the Wi-Fi Alliance says it's working with the LTE standards group 3GPP to ensure coexistence.
So far, unlicensed LTE has been designed for network operators that already have licensed frequencies. They plan to use unlicensed spectrum for data downloads while keeping other traffic, such as voice calls, on a cellular band. But a new technology in the works at Qualcomm would form "LTE-based" networks using unlicensed spectrum alone. It could allow businesses, cable companies, hotspot operators and big venues like sports stadiums to deploy LTE instead of Wi-Fi wherever they wanted, without any licenses.
Qualcomm says its new system, called MuLTEfire, would deliver "LTE-like" performance, like enhanced capacity and range, while being easy to deploy like Wi-Fi. It won't hurt nearby Wi-Fi users, the company says. Indeed, Qualcomm claims that using unlicensed LTE instead of Wi-Fi can actually improve the experience of nearby Wi-Fi users because LTE is more efficient. But if MuLTEfire catches on -- presumably under a catchier name -- it may lead to a lot more LTE networks vying for unlicensed airwaves.
That's a big "if." Wi-Fi already has LTE beat for cheap, ubiquitous radios in mobile devices, and the unlicensed variant of LTE is a new one that will take time to show up in devices. So it's hard to see why anyone would choose LTE over Wi-Fi for a new unlicensed network, analyst Peter Jarich of Current Analysis said.
First of all, even though private businesses could deploy a fully unlicensed LTE network, it's unlikely they would, analysts say. Enterprise Wi-Fi is so mature and available from so many vendors that companies would have no reason to get involved in a whole new technology that was designed for carriers.
Where LTE does have an edge over Wi-Fi is in advanced, standardized mechanisms for things like subscriber authentication, policy-based management and coordinating among base stations. Those features might make it easier to set up a service-provider network with MuLTEfire than with Wi-Fi, analysts said.
Some emerging service providers have expressed interest in LTE for use solely in unlicensed spectrum, according to Tolaga Research analyst Phil Marshall. In addition to cable operators that want to supplement their services with mobile, adopters might include wireless carriers that can't get spectrum licenses in all the places they want to serve. That might mean, for example, AT&T setting up LTE service in foreign countries on unlicensed spectrum, but it's more likely to be a strategy for service providers in Europe that want to cross borders, Marshall said.
"There's a few scenarios that work, but obviously the ecosystem has to be developed," Marshall said.
Wi-Fi network operators and vendors have worked for years to match cellular in one area: the ability to roam onto and among different networks. Hotspot 2.0 technology has been gradually refined and is in use on some networks, but the ease of use it's promised has fallen short, Jarich said. That might be behind efforts to bring LTE into the Wi-Fi band, he said.
"The experience hasn't been there," Jarich said. "Is that part of what's going on here"
Qualcomm itself may be a major force in determining if unlicensed-only LTE catches on. The company says it's working to develop industry-wide specifications for the technology. Qualcomm's commanding share of the mobile-device silicon market might give it the influence to bring MuLTEfire -- or whatever it's eventually called -- to scale.
Stephen Lawson covers mobile, storage and networking technologies for The IDG News Service. Follow Stephen on Twitter at @sdlawsonmedia. Stephen's e-mail address is stephen_lawson@idg.com