Then, there are some well-funded bidders with unknown motives, such as petroleum giant Chevron and Vulcan Spectrum. Also in the mix are some cable operators.

Besides the big players, many local and regional wireless carriers have applied to participate in the auction and are likely to bid on the regional chunks of spectrum. A local telephone company, for instance, could use such spectrum to provide wireless broadband service to its local customers using a technology such as WiMax.

What about Google's bid?
The potential bidder that has received the most attention is Google, which has been mum about its specific plans. Most observers believe the company's interest in the auction is tied to its recently announced Linux-based Android mobile phone system.

Google likely wants to use Android to sell mobile advertising. However, that won't be successful if existing wireless carriers don't allow phones based on it to be used on their networks. If Google owns the open C block, it will be certain that phones based on its Android system can be used.

Few, however, expect Google to create a whole new wireless network from scratch -- if it wins.

"Google will rent out the spectrum," said consultant Gold. "It would be insane on their part if they decided to put up their own network. Being landlords of the airspace, that makes sense."

As a result, it is widely expected that if Google wins the C block, it will work with other providers. For instance, rumors have been circulating that Google will work with T-Mobile USA, which has been constrained in expanding its network by a lack of spectrum. Neither company has been talking about such specifics.

How will the auction be conducted?
A "mock auction" will be held on Jan. 22, and the auction will begin in earnest two days later. Many observers believe the bidding, which will be largely electronic, could last a couple of weeks.

Bidding will be anonymous. That is to say, nobody will know who is bidding or how much they are bidding. The goal of this rule is to prevent collusion aimed at keeping out specific bidders.

"There are quite a few studies that show that, if you know who is bidding, you can engage in anticompetitive blocking behavior," said Public Knowledge's Sohn.

How much will spectrum cost
Buying spectrum will require very deep pockets. In particular, the large, nationwide spectrum blocks will surely be expensive. The C block, for instance, has a reserve, or floor, bidding price of about $4.7 billion. The total reserve price for all blocks is about $10 billion, and many believe the bidding will go much higher than that.