AT&T said it would take a big step to buy more wireless spectrum, a move that could improve performance of its problem-plagued mobile data network as the carrier moves to 4G. The deal announced Dec. 20 calls for AT&T to pay $1.9 billion to Qualcomm for spectrum in the 700MHz band. AT&T said the spectrum would cover more than 300 million people in the United States.

Qualcomm had reserved the spectrum for its mobile Flo TV service. Consumers who used the service could watch broadband television on cellphones. However the service did not prove popular and Flo TV will be shut down by March.

In 2007, AT&T paid $2.5 billion for spectrum owned by Aloha Partners, but its network has been plagued by low service ratings and congestion. The additional spectrum should help AT&T offer higher speeds and reduce network congestion. 

The 700MHz spectrum is reportedly effective over long distances and can penetrate barriers such as walls and windows. Television stations formerly used the 700Mhz bandwith but, as part of the move to all-digital television broadcasts, they were required to vacate that portion of the spectrum.

If regulators approve, the spectrum purchase is supposed to be completed in the second half of 2011. It seems unlikely that 3G and 2G customers will see any improvement in performance as a result of the deal, however, because AT&T's current network operates in the 850MHz and 1900MHz spectrums. It seems likely that the new spectrum will, instead, be used for AT&T's forthcoming 4G network, according to Time.

If, as expected, rival Verizon Wireless begins selling iPhones in 2011, that could give Verizon, which recently rolled out its LTE 4G network service, an advantage over the original iPhone carrier.