What’s AT&T planning? Hidden specs unearthed in the GSM iPhone 5

There’s more to the AT&T (s t) version of the iPhone 5 than meets the eye. ExtremeTech’s Neal Gompa sorted through the device’s testing documentation at the Federal Communications Commission and found there are two more 4G frequency bands supported in the North American GSM iPhone beyond those Apple revealed in its official specs.(s aapl)

Those bands are cellular and PCS, which operators today use for their 2G and 3G networks. The revelation is surprising, though it’s certainly not suspicious. Except for Sprint, no iPhone operator is launching LTE on those bands, and Sprint uses a different iPhone variant than AT&T. Apple had no reason to include those bands in its specs because there’s no network this particular iPhone could conceivably connect to – at least not yet.

The question is why Apple added these bands, and the answer is almost certainly because AT&T asked it to. AT&T is currently launching LTE over its 700 MHz network, and it has stated it will launch LTE in the Advanced Wireless Services (AWS) frequencies. But its spectrum holdings in AWS are dwindling as it just handed over a bunch of licenses to T-Mobile.

AT&T has made no secret of the fact it is hunting around for new bands over which to deploy LTE since its current LTE networks will only get it so far. It just submitted an enormously complex proposal to the FCC that would allow it to turn its now useless 2.3 GHz into a private LTE band. But these new frequencies in the iPhone hint at another possibility: Ma Bell may be planning to cannibalize its 2G and 3G networks to gain more LTE capacity.

AT&T has on average 55 MHz of PCS and cellular spectrum nationwide, and it’s pretty much all accounted for. In some parts of the country, AT&T has begun shutting down parts of its GSM network, but it isn’t replacing with it LTE, rather its building new HSPA networks. But now that the iPhone is fully LTE compatible, its mobile data burden will start shifting from 3G to 4G. When enough of that traffic has made the journey, AT&T could start shutting down 2G or 3G capacity. And once it clears out a contiguous 10 MHz chunk it could build an LTE network.

All US carriers will eventually refarm their 2G and 3G spectrum – T-Mobile has already shut down most of its GSM network — but it will likely take years before they seriously start messing around with those frequencies. That’s why it’s puzzling that the new iPhone supports those frequencies today. European operators are a year away from having sizable LTE network on their 2.6 GHz spectrum, yet Apple nixed those frequencies from all its iPhones. Why would it make cellular and PCS such big exceptions?

Either AT&T has enormous pull with Apple, convincing it to make an iPhone that will work on networks years away from being deployed. Or AT&T is planning a massive reconfiguration of its networks in the next year, something akin to the major network overhaul T-Mobile is doing today.