The Federal Communications Commission, under the leadership of freshly-confirmed chairman Tom Wheeler, is hard at work on rules that will govern an upcoming spectrum auction. AT&T and Verizon, the nation's largest wireless carriers, want the FCC to hold an unrestricted auction that could allow them to maintain or even widen their lead in premium low-frequency spectrum. Their smaller competitors, especially T-Mobile, are urging the FCC to adopt rules to guarantee that the largest carriers do not wind up with a disproportionate share of that spectrum.