The U.S. Federal Communications Commission approved Verizon Wireless’ $28 billion purchase of rival carrier Alltel. It also approved a $14.5 billion deal between Sprint and Clearwire to merge their wireless broadband networks.

But the vote that could have the most enduring effect on the wireless market was the FCC’s vote on rules for the use of idle TV spectrum commonly referred to as TV white spaces.

The acquisition of Alltel vaults Verizon Wireless, currently the No. 2 wireless carrier in the United States, into the top spot with more than 80 million customers, overtaking AT&T, which has 70 million customers. (see Verizon Wireless to Acquire Alltel)

Alltel gives Verizon Wireless, which gained large swaths of valuable 700 MHz spectrum at a recent auction, added flexibility as the wireless market awaits the emergence of LTE, a promising new wireless broadband technology.

The FCC approved the deal on the condition that the two companies divest spectrum licenses and other related assets in five markets. The agency said that the merger could harm competitiveness in those markets.

The Sprint-Clearwire deal creates a single nationwide network based on WiMAX, a wireless broadband technology that competes with DSL and cable modems in the home. (see Tech Consortium Bids $14.5B on WiMAX)

The new carrier inherits the Clearwire name and is owned by a consortium of major players including Sprint, Google, Intel, Comcast, Time Warner Cable, and Bright House Networks.

FCC commissioner Michael Copps lauded the deal as the “creation of a new competitor in the broadband Internet market.”

“This network will provide millions of Americans with an additional option in the market for high-speed fixed broadband access,” he wrote.

The white space rules establish conditions for the use of spectrum that was used as buffers between TV bands to avoid interference. The planned switchover to digital TV freed up these white spaces, and companies such as Google and Microsoft have lobbied for licenses to the spectrum to offer low-cost broadband services.

The rules are an attempt to assuage the concerns of broadcasters and those who use wireless microphones about interference from the use of white spaces for broadband communications.

The FCC requires the use of airwave-sensing technology to prevent interference. The technology is a major step toward opening up white spaces for low-cost wireless broadband communications.