Google tipped its hand Tuesday evening that it is still interested in participating in the January 700 MHz spectrum auction. The auction may be one of the most lucrative in U.S. history with speculation that it will bring in as much as $20 billion.

Delivering a keynote address at the Progress and Freedom Foundation's annual Aspen, Colo., technology conference, Google CEO Eric Schmidt said the search and online advertising giant would "probably" bid on some of the spectrum, according to a Reuters news story.

If Google enters -- and wins -- the high-stakes auction for the spectrum considered ideal for wireless broadband, it would create a third competitor to telephone and cable companies offering high-speed connections.

Google caused a stir earlier this summer when it announced it was willing to commit a minimum of $4.6 billion to the auction if the Federal Communications Commission (FCC) conditioned the sale of the spectrum on open access and wholesale principles.

In late July, the FCC issued the rules for the auction, agreeing with Google on open access but rejecting the Mountain View, Calif.-based company's request on wholesale access. Until Schmidt's Tuesday comments, Google has been mum on whether it would participate in the auction.

The landmark sale of the spectrum being deserted by television broadcasters as part of the digital TV transition is considered ideal for delivering advanced wireless services, including broadband that meets or exceeds the speeds of DSL or cable modems.

Under the FCC plan, more than a third of the spectrum for sale – enough to build a national network – would be reserved for an open-access platform that would allow consumers to connect any legal device or software to the network. Carriers would also be prohibited from blocking legal Internet content.

Dominant incumbent carriers like AT&T and Verizon have loudly complained that open access mandates would rig the auction in Google's favor.

"As we've previously noted, if Google is serious about introducing a competing business model into the wireless industry, Chairman [Kevin] Martin's compromise plan allows them to bid in the auction, win the spectrum and then implement every one of the conditions they seek," Jim Cicconi, AT&T's senior executive vice president, said in a July 31 statement.

None of the major carriers have yet to commit to bid on the auction.

Another chunk of the airwaves is set aside for the successful bidder to build and maintain a national, interoperable first responder network. Smaller pieces of spectrum will also be available for regional carriers to build networks or for incumbent carriers to help fill out their national footprints.