Details on AT&T’s LTE Rollout

AT&T has just turned on its first five LTE cities in Atlanta, Chicago, San Antonio, Houston and Dallas, Texas.

PC Magazine’s Sascha Segan sent a bunch of questions to AT&T, hoping to get further details. He got this response:

Q: How much spectrum is being used in each of the five LTE launch markets? 5×5, 10×10, 15×15?

A: We are currently using 10×10 in Atlanta, Dallas, Houston, and San Antonio, and are using 5×5 in Chicago.

Q: Why is buying T-Mobile important to AT&T’s LTE strategy; why not just spend that $39 billion building towers and cell sites?

A: Integrating T-Mobile into AT&T’s network brings a whole lot of additional efficiencies and capacity gains that AT&T could not get just by building a lot of new cell sites, which would not be feasible in the same time period. Those include improved network utilization, channel pooling, the elimination of redundant control channels, and other efficiencies that effectively provide the functional equivalent of new spectrum.

Q: When will we see the first AT&T LTE phones?

A: We plan to offer a 4G LTE handset later this year.

Q: Will AT&T go to VoLTE (voice-over-LTE)? Will you use wider-band codecs than you do on 3G, for better voice quality?

A: We are committed to deploying voice over 4G LTE as our 4G LTE footprint is built out further and we have technology in place to ensure our customers have a great experience with voice over 4G LTE.

Q: Will AT&T’s LTE ever interoperate or roam with other LTE networks, such as Verizon’s or MetroPCS’s? After all, you have 3G roaming.

A: It’s too soon to speculate on that. There are many technical challenges that must be addressed, due to the many different spectrum bands that carriers around the world are using to deploy 4G LTE.

AT&T currently offers four 4G LTE-compatible devices: the HTC Jetstream tablet, the AT&T USBConnect Momentum 4G, the AT&T Mobile Hotspot Elevate 4G, and the AT&T USBConnect Adrenaline.

AT&T’s de la Vega said the company’s LTE phones will rely on circuit-switch fallback when moving from LTE. Verizon’s LTE phones use separate 4G and 3G radios that each require their own power source and use more power. Qualcomm’s MDM9600 is used inside HTC’s Thunderbolt handset but alongside a Snapdragon MSM8655 which is combination application processor and CDMA modem. As a result the handset has a short battery life.

AT&T’s de la Vega promises to deliver slim, power-efficient LTE phones, perhaps using Qualcomm’s S4 Snapdragon chips which include a baseband supporting both LTE and 3G radios. Qualcomm says it will support all the “commonly used LTE frequencies” between 700 to 2,600 MHz at bandwidths up to 20 MHz.

If Sprint could (only) prevent the AT&T/T-Mobile merger, it might sell off some of its spectrum. But T-Mobile may be worth more dead than alive.

Verizon, MetroPCS, and AT&T will account for the majority of LTE connections globally by year-end 2011. Pyramid Research expects that the US, with 7m LTE connections, will account for 47% of the world’s LTE subscriptions.

Posted by Sam Churchill on .

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