US regulator the Federal Communications Commission (FCC) begins its Auction 110 today (5 October), giving the country’s operators another chance to acquire more mid-band spectrum for 5G.

The frequencies up for auction sit between 3.45GHz and 3.55GHz, part of a so-called “sweet spot” for 5G because of the mid-band mix of propagation and capacity. Currently, the spectrum is used by the US Department of Defence for radar services.

The frequencies are directly adjacent to the Citizens Broadband Radio Service bands, which the FCC has designated as shared spectrum that can be used by enterprise.

Thirty-three companies qualified to bid in Auction 110, including the three nationwide operators, Verizon, T-Mobile US and AT&T. Dish Network, which is building a greenfield, cloud-based open RAN 5G network, is also set to bid.

Spectrum will be auctioned in each of the nation’s Partial Economic Areas (PEAs), with 10 blocks of 10MHz each available in most PEAs. Minimum opening bids range from $7.5 million in New York to $1,000 in several smaller municipalities.

Analysts surveyed by Bloomberg predicted AT&T will spend an estimated $10.2 billion in this auction, more than any other bidder. They projected total spending will approach $25 billion, less than a third of the $81 billion spent in the recent C-Band auction.