After more than a year of rancor over whether it would hurt Wi-Fi, a technology that lets LTE networks use unlicensed spectrum may have already missed its window of opportunity.
LTE-Unlicensed is designed to improve cellular service by tapping into some of the frequencies used by Wi-Fi and other unlicensed technologies. But almost as soon as LTE-U was proposed in late 2014, Wi-Fi supporters pounced. They charged that it would drown out Wi-Fi signals because LTE didn’t know how to make room for other users.
Backers of LTE-U said adding it to a room full of Wi-Fi gear caused even less interference than adding another Wi-Fi access point.
Now carriers may be getting ready to bypass LTE-U altogether in favor of another system, called LAA (Licensed Assisted Access), that does the same thing but with additional protections for Wi-Fi. The LAA standard is complete, and products are expected to start shipping later this year.
“LTE-U might be deployed, but it’s not for very long,” Tolaga Research analyst Phil Marshall said. “It’s hard to see why an operator would focus on LTE-U when LAA’s right behind it.”
Qualcomm, LTE-U’s biggest backer, is already shipping components for LTE-U cells and mobile devices. Carrier equipment giant Ericsson has a commercially available LTE-U cell feature.
Verizon Wireless, T-Mobile, SK Telecom and other carriers have shown interest in the technology. Verizon said it still plans to deploy LTE-U later this year. In comments made in January, a Verizon executive described that as a limited trial deployment.
But Qualcomm is also developing and demonstrating components for LAA that are due later this year, and Ericsson announced last month that its LTE-U software would be upgradable to the newer system. SpiderCloud Wireless, another vendor developing LTE-U gear, also plans to make it upgradable. Most carriers considering LTE on unlicensed spectrum are studying both technologies.
“It’s kind of a question mark whether operators will commercialize LTE-U or go straight to LAA,” Matt Branda, Qualcomm’s director of technical marketing for cellular, said last week.
LAA has two big advantages. First, it includes a “listen before talk” feature to overcome what critics call LTE-U’s biggest flaw: that it may start transmitting even if another radio is using the same channel. Second, it’s part of the official LTE standard, which carriers count on to make sure their systems work and can grow into the future.
Those pieces were needed just to get an unlicensed LTE technology approved in most parts of the world. So from the start, LTE-U was limited to a few markets, primarily the U.S., China, India and South Korea.
LTE-U was intended as a way to get unlicensed LTE out into the market without waiting for the 3GPP, which governs LTE, to build LAA into the next release of the standard. But the fight over coexistence with Wi-Fi further narrowed what was already a brief gap for LTE-U to fill.
“This process has taken longer than some of the advocates of LTE-U were anticipating,” Marshall said. After months of conflict, a light finally appeared at the end of the tunnel when both sides agreed to create a testing regimen.
So, is this a victory for opponents of LTE-U? Not necessarily. Vendors may have been overly optimistic if they expected carriers to jump on a new, interim technology just for a brief head start. Mobile operators like their gear to meet global standards, and it usually takes them longer than expected to roll out anything new, said analyst Peter Jarich of Current Analysis.
Plus, LAA appears ready to march forward with little opposition from Wi-Fi backers. This might be thanks in part to the battle that’s already been fought over LTE-U, said Marshall, who believes neither system actually poses a threat to Wi-Fi.
Without LTE-U, “it would have played out with LAA being the focal point of concern,” he said.