Cellular data is about to take its next big leap, one its supporters say will improve service on carriers such as Verizon and T-Mobile. Its critics, however, say it could undermine Wi-Fi, a free technology that handles roughly half of the Internet’s mobile traffic.
It’s called LTE-U, and it’s being developed by Verizon, the chipmaker Qualcomm and other telecom companies. The innovation represents the next evolution in mobile data and a flash point for two gigantic industries.
If you use any of the four major cell carriers, you’re probably familiar with 4G LTE mobile-data technology. Under ideal conditions, it provides download speeds that rival a wired connection – fast enough to download a song in less than a minute.
LTE-U has one key difference from LTE: It runs on the same frequencies as Wi-Fi. Unlike LTE, which piggybacks on airwaves owned by your carrier, LTE-U travels on free public airwaves. Garage door openers, cordless phones and Wi-Fi routers also transmit over these channels.
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Industry engineers say LTE-U is faster and will make the most difference in crowded areas, such as cities and universities, where networks tend to get congested.
Under LTE-U, your device will probably report being on “LTE,” just as it always has. But its introduction reflects an unprecedented move by wireless carriers onto open airwaves – known as unlicensed spectrum – and that’s going to have repercussions.
To cellular providers, Wi-Fi represents a huge missed opportunity. Internet consumption on cellular data networks – your 3G or 4G connection – could have grown 84 percent last year, according to Cisco. But because consumers shunted so much traffic to Wi-Fi, that figure was lower, 69 percent.
Carriers could charge you for all that extra access to the mobile-data network. Instead they’re losing out when you hop onto Wi-Fi. LTE-U is the industry’s solution.
The cable industry, on the other hand, wants to keep you on Wi-Fi as much as possible.
This is the math they fear: By 2019, Americans are expected to consume nearly 10 times as much mobile data as they did in 2014. By then, 77 percent of all Internet traffic will be sent and received over mobile devices rather than stationary PCs. That’s not good for cable, an industry that built its reputation on running fast (but fixed) Internet service into people’s homes and businesses.
“Wireless is king,” said Robert Pepper, Cisco’s vice president of global technology policy.
To keep up, cable companies will need to offer a solution that lets customers use their services outside the home.
The workaround: Instead of keeping subscribers chained to their cable boxes, companies are letting them take advantage of other people’s routers, too. This means that if you’re a Comcast customer in Philadelphia, you can log on to any eligible Xfinity hotspot in, say, Washington. Thanks to a roaming agreement for cable-powered Wi-Fi hotspots, Comcast customers can even use routers belonging to Time Warner Cable in New York.
In 2012, the cable industry’s Wi-Fi consortium had 100,000 public, out-of-home Wi-Fi hotspots to its name. Today, it’s more like 400,000, creating a rudimentary if patchy equivalent of a cellular network.
Firms such as Cablevision have experimented with providing a kind of cellular service over Wi-Fi in recent months. Non-cable companies such as Google and Republic Wireless also believe Wi-Fi can cheaply support voice calls with less reliance on the traditional cellular network run by companies such as Verizon and AT&T.
Both industries need each other. Cellular providers rely on the Wi-Fi network to ease congestion on their proprietary networks, and the cable industry probably won’t be able to provide a compelling cellular experience without partnering with a cell provider in areas lacking coverage.
But there’s no denying that as each becomes more like the other, the cable and cellular industries increasingly compete for customers.
Can they coexist?
Tension stems from something else, too: a fundamental difference in technical design that could strangle Wi-Fi, giving cellular providers the upper hand over cable companies, according to LTE-U’s critics.
Because it has to share the airwaves with so many other wireless devices such as Bluetooth headsets and wireless mice, Wi-Fi antennas follow a “politeness” protocol that controls when they transmit and receive data. When your smartphone is on Wi-Fi and it senses other devices communicating over the same frequencies, it backs off until the channel is clear. It’s a lot like the principle of yielding to pedestrians in a crosswalk.
That’s not the case with LTE, in part because LTE was designed with proprietary networks in mind. So if left unchecked, it could prevent Wi-Fi devices from uploading or downloading content from the Internet – the equivalent of running through the crosswalk, the next five stoplights and over whoever might be in the way.
Interference between the two technologies can slash Wi-Fi transmission rates by 75 percent, according to a Google white paper filed recently to the federal government. The cable industry’s top trade group, the National Cable and Telecommunications Association, argued that the technology could be “disastrous” without further protections and “will severely degrade consumers’ Wi-Fi experience, rendering unusable many services that are widespread today, to say nothing of the innovative new uses currently on the horizon.”
Whether it’s voice calls, video conferencing or online games, services that rely on a steady Wi-Fi connection could be slowed or interrupted by LTE-U. It could affect schools, libraries, homeowners and small businesses.
LTE-U’s designers say they’ve implemented safeguards to ensure that it coexists peacefully with Wi-Fi. For instance, LTE-U turns on only when the cellular network is full and needs extra capacity. Even then, it can only help a device download data – it doesn’t have the ability to upload it.
“We’re very excited about LTE-U,” said Dean Brenner, Qualcomm’s senior vice president of government affairs. “It’s been designed from the ground up to be a very good neighbor to Wi-Fi, and in many cases, actually improves Wi-Fi throughput.”
A device running LTE-U will first look for the least occupied Wi-Fi channel to minimize the chances of interrupting Wi-Fi. And then it calculates, based on the number of other devices sharing the channel, what proportion of the time it’s allowed to be active on it. If there are three Wi-Fi-based tablets and an LTE-U smartphone on the same channel, the smartphone will adjust itself to talk only a quarter of the time.
Even this may not help much when Wi-Fi is experiencing heavy use, said Clint Brown, a director of wireless initiatives at Broadcom and the vice chair for the Wi-Fi Alliance.
“It may look for a clear channel,” Brown said. “But once it’s on a clear channel, odds are the way it provides fairness may be about how much time you use the channel rather than whether there’s traffic.”
European standard: LAA
Telecom industry officials say their effort to design a sharing mechanism that works is evidence of their goodwill toward Wi-Fi. After all, cellular providers rely on it, too.
One official for a large telecom company said that under the current rules, his firm could roll out the existing LTE on unlicensed airwaves today, but the resulting interference would make it a horrible experience – hence all of the work to develop LTE-U, which will be more polite.
This fight is already settled – overseas, anyway.
In Europe and Japan, rules on mobile data require carriers’ technology to listen before talking, just like Wi-Fi does by default. To meet that standard, a version of LTE-U called LAA, or License-Assisted Access, is being designed. An added benefit is that LAA is capable of uploads and downloads, unlike LTE-U.
So why doesn’t the U.S. cellular industry adopt that standard? The companies say they don’t want to wait around for LAA to be finalized when the demand for cellular data is growing so quickly.
The wireless trend
By 2019, Americans are expected to consume nearly 10 times as much mobile data as they did in 2014. By then, 77 percent of all Internet traffic will be sent and received over mobile devices rather than stationary PCs.