The Realities of The LTE-U Threat

This week’s translation comes from reader Chris, curious about how soon “LTE-U” will pose a threat to WiFi capacity and competition.

Refresher: “LTE” stands for “Long-Term Evolution,” the mobile industry’s term for super-fast broadband. The “U” is for “unlicensed,” as in, the opposite of “licensed,” both describing spectrum.

Mobile carriers move the stuff coming in and out of our mobile gadgets over licensed spectrum. They live there because they paid (exorbitantly) to be there, because what one owns, one controls.

Enter WiFi, increasingly our primary wireless broadband conduit. It operates in unlicensed spectrum, in the 2.4 GHz and 5 GHz regions.

As this column has noted before, WiFi is like Canada: Notoriously courteous. This is more a matter of necessity than any kind of digital altruism — because otherwise it just wouldn’t work. Your microwave, your Bluetooth stuff and other things all maneuver within the same unlicensed territories as WiFi.

LTE was built in a completely different design environment than WiFi. If you own your own spectrum and you’re building to communicate over it, you’re not designing a control plane that adjusts transmit levels or otherwise “backs off ” when unfamiliar traffic is present. Because it isn’t.

But what if the powers that be of LTE were to join in on the global WiFi melee, dumping globs of LTE traffic into the unlicensed territories? That a Google search on “LTE-U” returned 109 million links in 0.26 seconds is cause enough to consider it a valid concern.

Which brings back us to Chris’ question: “If LTE-U is not ‘if’ but ‘when,’ then, when?”

It depends. (Sorry.) It depends, for instance, on how quickly an LTE-U-motivated mobile carrier could install new gear into homes. “Gear” meaning base station, access point, femtocell — whatever it is, it’s the same refrain: Truck roll. Retrofitting existing gear for 5 Gigahertz isn’t exactly an option.

Likewise for our digital gadgetry: How soon will its radios be “dual mode” — 2.4 GHz and 5 GHz?

Then there’s the matter of the Federal Communications Commission, which shepherds the nation’s airwaves. (Recall that “unlicensed” isn’t synonymous with “unregulated.”) Would the keepers of the airwaves, which made it so that our WiFi stuff deliberately tries to work well together, allow a willy-nilly LTE-U traffic explosion? I’m guessing no.

It all brings to mind the earliest days of wired broadband, when telco DSL modems first entered the marketplace. A (still funny) Pacific Bell video ad showed people vandalizing their neighbors, suspecting them of being “bandwidth hogs.” (If you haven’t seen it, you must.)

What’s happening in wireless broadband in general — and WiFi specifically — isn’t all that different. It’s just a different hue, called LTE-U. Oh, the irony …

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