In a move that could eventually lead to free Wi-Fi across the United States, the FCC will conduct tests this week to see if the service interferes with T-Mobile's spectrum.

The federal agency is proposing to combine the 2155-2175 MHz band with the 2175-2180 MHz band to create a 25-MHz block of spectrum for a single nationwide license. This would then be auctioned off with the stipulation that the winner would have to use part of the spectrum to provide free wireless broadband.

Additionally, the Wi-Fi could be ad-supported, and the provider would have to "provide a network-based filtering mechanism for the free Internet service in order to protect children and families, and a requirement that the network allow for the use of open devices," the agency said in a written statement.

But T-Mobile fears that this free Wi-Fi could potentially interfere with the devices it has running on its Advanced Wireless Services spectrum, also known as AWS. T-Mobile spent more than $4 billion in 2006 to acquire this spectrum, and it is currently using it to roll out its UTMS/HSDPA 3G network.

T-Mobile is currently the fourth-largest mobile carrier in the United States, and high-speed mobile broadband would enable it to increase competition with other carriers for data-heavy users. It would also allow the company to offer more sophisticated handsets like the Sony Ericsson TM 506, as well as upcoming Android-powered devices.

T-Mobile is not the only wireless carrier opposed to the FCC's free Wi-Fi plan, as the Cellular Telecommunications Industry Association has voiced its concerns multiple times.

"The proposal upends two decades of spectrum policy in favor of a specially tailored auction designed to advance the particular business model of a single company. Moreover, this business plan - including free broadband - has a track record of failure," CTIA wrote in a letter of complaint earlier this year.