A sale of communications airwaves by the federal government to the commercial wireless industry closed Tuesday, after 261 rounds of bidding and $19.6 billion in bids.The Federal Communications Commission has not revealed who the winners of the valuable radio spectrum licenses are

The sale has been among the most closely followed in the 15-year history of airwaves auctions as the spectrum being sold has the ability to transmit signals over vast geographic distances and through buildings in urban settings.

Commercial wireless companies are expected to use the spectrum to support fourth generation, or 4G, cellular service. This is expected to include high- speed wireless broadband service at similar speeds to wired Internet connections.

The auction potentially pegged incumbent wireless service provider Verizon Wireless against newcomer Google, which had committed itself to participate in the auction.

Last year, Google lobbied aggressively for so-called open-access rules to be put in place which would force the winner of a large section of the spectrum to allow any handset device and any software application used over the wireless network subsequently built.

After the FCC agreed to implement these conditions, major wireless carriers like Verizon Wireless and AT&T Inc. both made pledges to introduce greater openness to their own networks.

The final price tag of $19.6 billion was considerably more than the estimated $10 billion to $13 billion the auction had been expected to generate.

This was the largest amount ever raised in an FCC spectrum auction.