Planned for October, 2021

Auction 110 of the 3.45 to 3.55 GHz band is planned for October, 2021.
According to FCC in FCC 21-33:

Auction 110 will offer up to 100 megahertz of spectrum divided into ten 10-megahertz blocks licensed by geographic areas known as Partial Economic Areas (PEAs), for a total of 4,060 flexible-use licenses across the contiguous United States. The proposed auction procedures would include a clock phase for bidding on generic blocks in each geographic area followed by an assignment phase for bidding on frequency-specific license assignments. The Public Notice proposes bidding credit caps and specific upfront payment and minimum opening bid amounts. Flexible-use licenses made available through this auction are subject to cooperative sharing requirements to protect federal incumbents, so the Public Notice proposes a reserve price of over $14.7 billion in order to meet the requirement that auction proceeds cover the expected sharing and relocation costs for federal users in the band.