Say you’re mingling in a room full of people, enjoying a tasty beverage. It’s a polite room of people who listen, responding during pauses. (So you’re in Canada!)
Out of nowhere, a mass of large, loud people enters the room, shouting instructions to each other. It’s like they’re oblivious to anyone who isn’t them.
In wireless protocols, the Canadians are WiFi. The Large Louds are LTE.
Here’s what happens next: The Canadians still want to converse. Their only option? Talk louder. The volume in the room goes up, and up, and up. The loud people keep piling in the door, with no signs of leaving. Suddenly, it’s not such a good time anymore.
This is one way to think about a red-hot topic touching WiFi people, known as LTE-U. The “LTE” stands for Long Term Evolution, a term mobile carriers use for fast, wireless broadband. The “U” stands for “unlicensed.”
Consider: About 200 MHz of spectrum exists for WiFi transmissions, including the extra 100 MHz the FCC granted in March, in the 5 GHz band. Right now, that spectral slice is carrying 50 to 60 percent of the Internet’s traffic.
Mobile carriers, by contrast, maneuver their traffic over some 600 MHz of spectrum — licensed spectrum, meaning they paid for it. (Dearly.) Some two to three percent of the Internet’s traffic moves within it.
So, right off the bat, WiFi is moving 30x the load, in one-third the space. Which brings us to how WiFi works, and the fact that just because its spectral zone is unlicensed, doesn’t mean it’s unregulated.
WiFi is built for spectrum sharing. It waits to talk, and it adjusts its transmit power as part of a design goal that purposefully wants to be a good neighbor, all the time — partly because of regulations that govern things like transmit power and sharing.
LTE is different. For starters, it uses “tunneling protocols.” That means that when a device connects, a secret tunnel is instantly established between it, and the carrier’s LTE network. Each data packet is both encrypted and encapsulated; the only visible parts are the packet’s source (who am I?) and destination (where am I going?)
Meanwhile, the LTE “control plane” — the servers and software that handling signaling and routing — is ceaselessly talking, back and forth, making sure everything’s doing what it’s supposed to be doing.
Here’s the concern: That LTE traffic will deliberately dump into the unlicensed territories, offloading giant blobs of traffic that can’t see or hear what’s already there. Such as anything moving over WiFi.
Is this a real problem? Not yet. Could it be? Definitely. (O, Canada! We stand on guard for thee.)
This column originally appeared in the Platforms section of Multichannel News.
In a late 2008 interview, conducted at Cox’s Atlanta headquarters, I speak with VP of Technology Jay Rolls about buying wireless spectrum, and the reasons why Cox chose to build its own wireless plant, using LTE. Directed and produced by the fabulous David Knappe with equally fabulous Joe Bondulich on camera and lighting.
Video courtesy Multichannel News.
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