While Wall Street and the telecom world waits with bated breath to see if U.S. regulatory officials allow the proposed AT&T and T-Mobile merger to go through, the chairman of the FCC, Julius Genachowski, told CNBC that competition and AT&T's market share will be one of the major factors in approving the $39 billion merger.

“Competition has long been central to the FCC, it’s been important to me and that is what we’ll be looking at in connection with the review,” said Genachowski from Las Vegas, where he was attending the National Association of Broadcasters meeting.

He wasn't very long on details, however. Genachowski refused to discuss other details of the review by the FCC and US Justice Department.

He doesn't expect the FCC's “net neutrality” rules to be reversed. These rules, passed by the agency in December, prohibit phone and cable companies from interfering with Internet traffic on their broadband networks. The U.S. House of Representatives passed a resolution Friday overturning the rules but the Senate has not acted.

“We don't think the industries want the rules to be reversed,” said Genachowski.”This is an issue that is now behind us. We have sensible rules of the road in place that are encouraging investment and innovation.”

With the exploding use of tablets and smartphones, Genachowski said he supports voluntary incentive options under which broadcasters give up spectrum for wireless broadband and share in the proceeds with the US government.

“We can free up significant amount of spectrum using market forces,” he said.