T-Mobile USA definitely has milked the AWS spectrum it acquired in the FCC's auction in 2006; the carrier launched 3G service on the band in 2008, and has since upgraded the network to HSPA+ technology, which it markets as "4G."
Nonetheless, T-Mobile remains a step behind its nationwide rivals, which are all in the process of building out next-generation networks on unused airwaves. (Sprint Nextel's (NYSE:S) 4G play works over Clearwire's (NASDAQ:CLWR) 2.5 GHz spectrum, Verizon Wireless' (NYSE:VZ) LTE network runs on its 700 MHz spectrum, and AT&T Mobility (NYSE:T) has said it will deploy LTE on its AWS and 700 MHz holdings.)
T-Mobile has long been rumored to be in discussions with Clearwire for a possible wholesale relationship, whereby it would resell Clearwire's services under the T-Mobile brand. However, the companies have yet to announce a deal, which could indicate T-Mobile is pursuing its other 4G options.
Indeed, the nation's No. 4 carrier has been lobbying the FCC to auction two blocks of spectrum licenses it could use to build a LTE network (though it remains unclear how the carrier would market such an offering since it has already bestowed the "4G" moniker on its existing HSPA+ network). In a series of meetings with FCC staff, T-Mobile has pushed the agency to offer up both AWS-3 and D Block spectrum for auction, presumably so the carrier can bid on the airwaves and subsequently use them for an LTE deployment.
Given the FCC's renewed focus on freeing spectrum for mobile broadband, and T-Mobile's lobbying on the topic, we expect the carrier to make a serious play for AWS-3 and D Block spectrum via an FCC auction.