CTIA officials disputed the Citigroup report's numbers, saying Bazinet and Rollins appear to be using information from 2010. More spectrum has gone into service this year, CTIA said, with Verizon Wireless, for example, launching 4G service on the 700 MHz band of spectrum to more than half the country since late 2010. Verizon won 22 MHz of spectrum in the C block of the 700 MHz band in an FCC auction that ended in early 2008.

The report uses numbers that are foreign to CTIA, said Chris Guttman-McCabe, the trade group's vice president for regulatory affairs. "I dispute each of the elements of it," he said. "Where did they get the 500 MHz, and where did they get the 190? I would dispute each of their numbers."

Guttman-McCabe questioned why the report included LightSquared spectrum, when it is tied up in regulatory limbo. He also disputed Citigroup's description of 194 MHz available in the Broadband Radio Service (BRS) and Educational Broadband Service (EBS) bands between 2.4 and 2.7 GHz, when an only 55.5 MHz available for mobile broadband in those bands.

The U.S. mobile carriers use their spectrum more efficiently than carriers in any other nation, CTIA officials said, yet several other developed nations are in the process of making more spectrum available, or are looking for more spectrum.

"Every other country out there is bringing hundreds and hundreds of megahertz to market," Guttman-McCabe said. "What's the magic secret in the sauce that Citigroup knows that no one else does?"