1. Short title This Act may be cited as the Investing in America's Digital Infrastructure Act . 2. Definitions In this Act: (1) C-Band Reimbursement Fund The term C-Band Reimbursement Fund means the fund established under section 5(a). (2) Commission The term Commission means the Federal Communications Commission. (3) Digital Divide Trust Fund The term Digital Divide Trust Fund means the trust fund established under section 4(a). 3. Public auction of C-band spectrum (a) In general Not earlier than June 1, 2021, and not later than December 31, 2021, the Commission shall— (1) identify not less than 200 megahertz of the electromagnetic spectrum described in subsection (b) for reallocation consistent with this section; (2) clear the spectrum identified under paragraph (1) consistent with subsection (f); (3) reallocate the spectrum identified under paragraph (1) for terrestrial broadband use, reserving 20 megahertz of the spectrum as a guard band; and (4) notwithstanding paragraph (15)(A) of section 309(j) of the Communications Act of 1934 ( 47 U.S.C. 309(j) ), begin a system of competitive bidding under that section to grant new initial licenses for the use of the spectrum identified under paragraph (1) of this subsection, subject to— (A) flexible-use service rules; and (B) the requirement to protect incumbent uses of the spectrum not otherwise cleared under paragraph (2) of this subsection from harmful interference. (b) Electromagnetic spectrum described The electromagnetic spectrum described in this subsection is the spectrum between 3700 megahertz and 4200 megahertz, inclusive. (c) Auction proceeds Section 309(j)(8) of the Communications Act of 1934 ( 47 U.S.C. 309(j)(8) ) is amended— (1) in subparagraph (A), by striking and (G) and inserting (G), and (H) ; (2) in subparagraph (C)(i), by striking and (G) and inserting (G), and (H)