Dish Network has been running into interference from AT&T in its efforts to build a new LTE-Advanced network, and the FCC just dealt it another blow. The Wall Street Journal is reporting that the FCC has denied Dish's request for a waiver that would have let it immediately offer cellphone service using spectrum it purchased last year. Instead, a review will be conducted to determine whether Dish's sliver of the 2GHz band is suited for such a network. The move comes after the FCC was forced to revoke a similar waiver granted to LightSquared, which had hoped to use spectrum in the same band to build out a new LTE network itself. Complaints over possible GPS interference led to an investigation by the National Telecommunications and Information Administration, and the FCC eventually pulled LightSquared's waiver. It's unclear how Dish will proceed given the setback, but we wouldn't be surprised to hear more chatter about selling the spectrum sooner rather than later.