AT&T Won't Stifle T-Mobile's Phone Selection

T-Mobile US Inc. customers won't automatically get the iPhone 4 if AT&T Inc. (NYSE: T)'s acquisition goes through, but they will have a lot more 3G handsets to choose from to ride both carriers' networks than AT&T's customers will.

While both carriers run GSM networks and are both in the process of updating them to support 21Mbit/s High-Speed Packet Access (HSPA)+, they operate in different, incompatible frequency bands. AT&T runs on 850MHz and 1900MHz frequency bands for uplink and downlink, while T-Mobile operates on paired 1700MHz/2100MHz AWS spectrum.

As such, the only smartphones that roam between AT&T and T-Mobile's 3G networks are world phones, designed for international travelers.

All of AT&T's most popular models, like the Apple Inc. (Nasdaq: AAPL) iPhone 4 and iPad 2, lack support for 1700MHz, meaning they will only bust back to T-Mobile's compatible EDGE network when the two become one.

T-Mobile customers, on the other hand, will have 27 devices to choose from, including the carrier's latest smartphone, the myTouch 4G Slide. Other HSPA (7.2Mbit/s) or zippier HSPA+ devices at their disposal include:

Most of the merger talk has focused on how T-Mobile will bolster AT&T's Long Term Evolution (LTE) deployment plans, but the carrier will also have to integrate these legacy phones on AWS spectrum. While AT&T may commission new dual-frequency handsets to support both networks in the future, its existing smartphones won't benefit from the bolstered network capacity.

Purchasing world phones with the dual-frequency support makes more sense for T-Mobile customers anyway, since they are the ones getting kicked off their frequencies once the merger closes. But, the big holdout remains, of course: When will Apple build an iPhone that supports T-Mobile's frequencies as well? (See Could AT&T/T-Mobile Deal Mean an HSPA+ iPhone?)

Light Reading Mobile will have more on that soon.

— Sarah Reedy, Senior Reporter, Light Reading Mobile

Roger Entner 12/5/2012 | 5:00:45 PM
re: AT&T Won't Stifle T-Mobile's Phone Selection

Because of component space, energy consumption, and deveopment and component cost. If you want a bigger phone that costs more and has less batter life then you can certainly add these components. Alternatively you can make more different phones, one for each frequency/technology, which then adds development costs and manufacturing cost because you have to keep several production lines running and the inventory is not fungible anymore. Right now Apple has to predict how many iPhones 4 16MB it sells, not how many iPhone 4 16MB 850/1900 MHz HSPA, iPhone 4G 16 MB 900/1900 MHz HSPA, iPhone 4G 1850 HSPA+, iPhone 4G 700 MHz LTE, iPhone 4G 2100 MHz LTE, etc it will sell. Much easier to predict one number than 5 or 10... 

shashidhara 12/5/2012 | 5:00:45 PM
re: AT&T Won't Stifle T-Mobile's Phone Selection

why iphone is not able to support all frequencies ?

Eric Kainer 12/5/2012 | 5:00:44 PM
re: AT&T Won't Stifle T-Mobile's Phone Selection

Note that, in addition to using its AWS spectrum for HSPA+ service, T-Mobile uses its PCS (1900MHz) spectrum for 2G service.  In fact, given the lack of AT&T / T-Mobile interoperability at AWS, this is the only spectrum allowing roaming between the carriers.  As such, the 1m+ iPhones running on T-Mobile use this PCS band exclusively.

Further, the article notes that T-Mobile has 21 Mbps HSPA+ services.  In fact, T-Mobile is rolling out 42 Mbps HSPA+ services rather aggressively, although device support for this speed is limited to the Rocket, if memory serves.

joset01 12/5/2012 | 5:00:44 PM
re: AT&T Won't Stifle T-Mobile's Phone Selection

Thanks Roger!


That's might also be part of why Apple is taking a while with LTE, because they'll want to figure out how to do 3G support and 4G in the phone, while keeping the slim form factor.

joset01 12/5/2012 | 5:00:39 PM
re: AT&T Won't Stifle T-Mobile's Phone Selection

Yeah, just the Rocket so far on 42+, I figure that Samsung has a smartphone in the works.

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