AT&T buys T-mobile: The 4G race is on in the US

While it’s true that T-Mobile and AT&T each use GSM technology, the carriers also use different bands of spectrum to deliver their services. Specifically, T-Mobile uses the spectrum it bought in the AWS spectrum auction in 2006 to build its 3G wireless network. AT&T also acquired spectrum in that auction. And it is using this AWS spectrum to build its LTE network. AT&T uses its 850MHz and 1900MHz spectrum to deliver its 3G service. Part of the reason that AT&T wanted T-Mobile in the first place was to get more of the AWS spectrum for its LTE network. Meanwhile, T-Mobile has no additional spectrum to deploy LTE, since it’s been using the AWS spectrum for its 3G service. What this means is that once AT&T and T-Mobile merge, AT&T will have to move all of T-Mobile’s existing 3G customers (which includes the supposed 4G HSPA+ customers) to AT&T’s 850MHz and 1900MHz spectrum. This means T-Mobile customers will need new handsets, since the existing T-Mobile 3G HSPA and 4G HSPA+ handsets will no longer work on the AWS spectrum.

Of course, integration still takes time - even for compatible networks. CNET’s Maggie Reardon perfectly sums up the 4G challenges that lie ahead for AT&T in integrating T-Mobile (if the deal gets regulatory approval): Read more at www.techrepublic.com