AT&T secure in decision to go with LAA and skip LTE-U

AT&T
By the end of 2017, AT&T expects to deploy LAA and 4-way carrier aggregation in certain areas of its 5G Evolution markets.

AT&T is feeling pretty good about its decision to forego LTE-U and go straight for the standards-based LAA. After all is said and done, both technologies are hitting the market at about the same time, despite earlier thoughts that LTE-U would provide a significant time-to-market advantage over LAA.

“We certainly looked at LTE-U and looked at the ecosystem and in fact did some early testing with LTE-U, but frankly the standards from an LAA perspective were progressing pretty quickly,” Gordon Mansfield, vice president of RAN and Device Design at AT&T, told FierceWirelessTech. Plus, LAA has the full-blown listen-before talk capabilities and was created in a standardized way.

AT&T yesterday announced it was launching 5G Evolution services in parts of Indianapolis, and one of the technologies it’s using in its 5G Evolution markets is LAA, which is expected to play a key role as it aims to reach theoretical peak speeds of up to 1 Gbps at some small cell sites this year.

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Conversely, Verizon and T-Mobile have been big proponents of LTE-U, which was developed outside the usual standards bodies. Last month, T-Mobile announced it was the first national wireless provider to make LTE-U available to customers; it also plans to deploy LAA. The Samsung Galaxy S8 and S8+ is the first handset on the market to take advantage of both LTE-U and LAA.

AT&T’s Mansfield said when he and his team looked at when the LAA standards were going to be available versus when LTE-U ultimately was going to be productized, the time difference between the two appeared to be minimal.

“For us, going straight to LAA versus taking that interim step to LTE-U just didn’t make sense,” he said. “I think everybody in the industry will ultimately land on LAA, they’ll just have to evolve what they do first in LTE-U to get there and we’re just going to go straight [to LAA].”

With LAA, both indoor and outdoor products are becoming available at basically the same time. “If I look at the capabilities of the two, LAA is going to come out of the gate with greater capabilities than LTE-U” and right about the same time or within about a month or so of each other, Mansfield said. “So it just doesn’t make a whole lot of sense to do the nonstandards approach first for us.”

AT&T is now conducting tests now with LAA and 4-carrier aggregation. On the device side, one should assume that phones will either get software updates to support it or new phones coming out this year will support 4-carrier aggregation.

“The network work is going on,” Mansfield said. As soon as the devices launch, many areas across AT&T’s network will support it.

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AT&T made a choice that all of its pico cells and dense-area builds were going in with unlicensed radios and it prefers to use LAA capabilities instead of Wi-Fi. There are areas where, through agreements with municipalities or others, that Wi-Fi is supported but LAA will be the default.

From an interference management perspective, LAA is much more efficient due to the signaling; in Wi-Fi both signaling and user traffic goes over unlicensed, which can get tricky outdoors sometimes. “It’s just more efficient to utilize the LAA capabilities,” he said.

As for the 5G Evolution moniker, which some have criticized as being misleading, he said 5G is not a singular event. “There’s a lot of things that have to happen to enable 5G. We’re taking all of those steps now to evolve our network,” including moving to an increasingly virtualized environment that gets pushed out further to the edge.