LTE-U is a technology developed by Qualcomm that lets a service provider broadcast and receive signals over unlicensed spectrum, which is usable by anybody – specifically, in this case, the spectrum used by Wi-Fi networks in both businesses and homes. By opening up this new spectrum, major U.S. wireless carriers hope to ease the load on the licensed frequencies they control and help their services keep up with demand.
That demand for connectivity continues to grow on a scale that we’re in danger of running out of adjectives to describe – a recent Cisco estimate suggested that monthly global demand could top 24 exabytes (that’s 24 million terabytes) by 2019, a nearly 10-fold increase from today.
Since an increasing proportion of that demand is being felt by wireless networks, the crunch is on for the carriers, who have spent vast sums on purchasing the rights to chunks of the U.S. airwaves. The industry bought almost $45 billion worth of spectrum in the FCC’s most recent auction in February, and has been working hard on ways to squeeze the most out of what they’ve got. Hence LTE-U.
The catch, of course, is that LTE-U’s frequencies are already being used by every Wi-Fi access point in America, which means that it runs the risk of interfering with networks that home and business users rely on. While Qualcomm has sworn up and down that LTE-U will include features that will avoid interference with existing networks, there’s little independent proof of those claims.
Unsurprisingly, several outside experiments that pitted standard LTE technology or “simulated LTE-U” technology, in the case of one in-depth Google study, against Wi-Fi transmitters on the same frequencies found that LTE drastically reduced the throughput on the Wi-Fi connection. IEEE member and wireless expert Craig Mathias said that the way LTE deals with interference makes it dominate frequencies that it shares with Wi-Fi.
“LTE-U has a shorter backoff period, so it’ll grab the air faster than Wi-Fi can,” Mathias said. “So you can expect, in high-density deployments that LTE-U will have a rather deleterious effect on Wi-Fi performance.”
Consequently, consumer advocacy groups, as well as the wired broadband industry and other big players that rely on Wi-Fi, have been sounding the alarm about LTE-U. Michael Calabrese, who directs the Open Technology Institute’s Wireless Future Project, told Network World that the root of the problem is that Qualcomm and its partners (notably Ericsson) are acting unilaterally, ignoring the well-established standards bodies at the IEEE and 3GPP.
Operating outside of the usual structures, it’s difficult for the rest of the industry and the public at large to get any kind of firm assurance that LTE-U technology is going to play well with others, he said.
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