US regulators approved a plan Wednesday allowing telecom giant AT&T to expand its network with under-utilized spectrum from satellite radio operator Sirius XM. The Federal Communications Commission said it approved the plan submitted in June, when AT&T struck a deal with Sirius to use some of the spectrum for mobile broadband, while avoiding interference with radio. The deal comes as regulators try to free up more room in the spectrum to accommodate wireless Internet, amid surging use of smartphones, tablets and other wireless devices, and avert a so-called spectrum crunch. AT&T said it would use the spectrum for so-called LTE networks which deliver high-speed data to phones and other devices. \"We anticipate that the service rules adopted today will permit deployment of LTE technologies in the WCS band while ensuring that satellite radio services are protected from unreasonable interference,\" said AT&T vice president Joan Marsh. \"AT&T took real risks to develop this under-utilized band and is committed to devoting the resources necessary to unlock its full potential. We expect to commence deployment of LTE infrastructure in the band in as early as three years, allowing us to enhance our wireless broadband services,\" he added. \"Our customers will also win, as additional spectrum capacity becomes available to support surging mobile Internet usage.\"