Telecom giant AT&T has announced an agreement it made with Deutsche Telekom to buy its subsidiary T-Mobile USA for a total of about US$39bn. The buyer said the deal would give a "fast, efficient and certain solution" to spectrum exhaust challenges facing both AT&T and T-Mobile in the near future because of growing demand for mobile broadband.

AT&T said its mobile data traffic had grown 8,000% over the past four years. By 2015, the company expects it to reach 10 times what it was in 2010. "Put another way, all of the mobile traffic volume AT&T carried during 2010 is estimated to be carried in just the first six to seven weeks of 2015," the company's statement read.

If the deal is closed, AT&T may inherit T-Mobile's data centers, including one of its newest data centers in Washington State - a 30MW facility built by Sabey.

AT&T chairman and CEO Randall Stephenson said the transaction was a major commitment to strengthening and expanding the nation's critical infrastructure. If regulators approve the transaction, AT&T has committed to extend the reach of its 4G Long Term Evolution network to 46.5m individuals beyond current plans.

"Mobile broadband networks drive economic opportunity everywhere, and they enable the expanding high-tech ecosystem that includes device makers, cloud and content providers, app developers, customers and more," he said.

Deutsche Telekom chairman and CEO Ren├® Oberman said in addition to enhancing service to T-Mobile USA customers, the transaction gives value to its shareholders and enables it to retain its reach into the US market. Deutsche Telekom will receive an ownership interest in AT&T of about 8%.

AT&T expects synergies from the transaction to result in an additional US$3bn over the first three years following closing of the transaction. Total value of the synergies is expected to exceed the total purchase price.

Both companies' boards of directors have approved the cash-and-stock deal. AT&T has committed to paying $25bn in cash and the rest in stock value, although it has reserved an option to increase the cash portion by up to $4.2bn, as long as Deutsche Telekom receives at least a 5% stake in the company.

AT&T expects to close the transaction in about 12 months.