To do the same thing, carriers in most other countries had to wait for another technology called LAA (Licensed Assisted Access), which was being standardized by LTE's overseers at the 3GPP and took longer to finish. It uses different coexistence techniques that most Wi-Fi backers think are safer. Some U.S. carriers are planning eventually to use LAA, too.
Meanwhile, vendors and service providers are jockeying for position on several other frequency bands that may host multiple services.
The 3.5GHz band: The U.S., Australia, the U.K., and other countries around the world want to open up frequencies in the 3.5GHz band to mobile devices. Just adding this band to the channels available for Wi-Fi wouldn’t work because the exact frequencies available in each country are different, Tolaga Research analyst Phil Marshall said.
In some cases, mobile users of 3.5GHz will have to share the band with existing users, such as the U.S. Department of Defense. In the U.S. case, the military would get first priority in the few areas where it uses the spectrum, service providers could get a new kind of license in some local areas, and other users would get in line behind them.
Millimeter-wave bands: Millimeter-wave bands targeted for use with future 5G networks also seem to be bound for complicated sets of uses. In particular, the 50-70GHz frequencies are partly unlicensed and partly “lightly licensed” to incumbent users in some countries, Marshall said. Unlicensed spectrum, in general, is expected to play a big role in 5G, though exactly how won’t be totally clear for a few years.
DSRC band: Regulators in both the U.S. and Europe have grappled with coexistence between Wi-Fi and DSRC (Dedicated Short-Range Communications) systems that use frequencies around 5.9GHz. These include systems for cars to communicate with each other and with nearby objects like tollbooths, though adoption has been limited, especially in the U.S. In-car Wi-Fi systems have been accused of hurting DSRC performance, and in the U.S. there is a drive to force DSRC to share its spectrum with Wi-Fi.
What’s missing, at least in the U.S., is a standard way of defining harmful interference between technologies that are bound to overlap with each other because they use the same spectrum, Public Knowledge’s Feld said. There should also be a standard framework for settling fights over shared spectrum so the Federal Communications Commission, or industries the FCC prods to solve their own disputes, don't have to reinvent the wheel every time, he said.
Opening more frequencies for mobile Internet access should be good for users overall, analyst Marshall said. He doesn’t expect performance hits on Wi-Fi from LTE-U, for example.
But as consumers increasingly get their mobile access over frequencies shared by numerous technologies, the boost that comes from the extra spectrum may be a fleeting thrill, Marshall said.
"You're talking about very, very high capacity if you've got that spectrum available," Marshall said. "If you haven't, you push down to a lower rate."
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