WASHINGTON (Reuters) - The Federal Communications Commission said that the first phase in the largest auction of mid-band 5G spectrum to date had raised a record $80.9 billion in gross proceeds. The spectrum is key to next-generation 5G wireless networks and the bidding exceeds the prior highest spectrum auction that netted $44.9 billion. Winning bidders must also pay the costs of clearing the spectrum held by existing satellite users and $9.7 billion in incentive payments. Verizon Communications and AT&T are expected to be among the major winners of spectrum in the auction.