If AT&T and Verizon manage to shut out their smaller rivals in a critical LTE wireless auction, it would severely harm US wireless competition, according to the Center for Public Integrity. In a report it said that the pair of wireless giants spent nearly $30 million on lobbying last year, almost four times the $8 million paid out by Sprint and T-Mobile. The low-frequency 600MHz spectrum in question is highly valued for its long range and ability to penetrate buildings, necessitating fewer towers and lower infrastructure costs. AT&T and Verizon already control 74 percent of existing low-band frequencies, putting Sprint and T-Mobile at a significant disadvantage -- especially outside of cities. As a result, T-Mobile's CEO, John Legere has stressed the importance of the upcoming auction for the future of his company.