It may have been out of the headlines the last few weeks, but out of sight does not mean out of mind for AT&T when it comes to the merger between Sprint's Xohm WiMax service and Clearwire. It recently filed a petition with the FCC trying to block the merger in what would be a serious competitive threat to its own 3G network.

Anyone remember WiMax? In case you forgot, earlier this year, Sprint decided to bag going it alone with its WiMax 4G wireless network. Instead, it decided to merge operations with WiMax provider Clearwire. The goal of the merger is to get the 4G mobile broadband network to market faster and at a lower cost.

Not so fast, says AT&T.

On Thursday, it filed a petition with the FCC looking for more scrutiny on the deal. AT&T is complaining that the proposed merger "openly state[s] that they intend to compete with other national wireless providers -- including AT&T -- yet they fail to make the required showings necessary for the commission's review."

According to CNN, "In listing their holdings, AT&T said Sprint and Clearwire have discounted some of the airwaves they intend to use for the Internet service because it isn't operational yet. If those airwaves were to be taken into account, the proposed merger would be subjected to heightened scrutiny."

AT&T says it was forced to jump through all sorts of regulatory hoops in order to acquire rural cellular provider Dobson Communications back in 2007. In its view, Sprint and Clearwire are not being made to jump through as many hoops, and it doesn't think that's fair.

Or is something else motivating AT&T? Could it be, perhaps, that the proposed WiMax network also has the support of tech big-wigs Google, Intel, and others? With more than $3 billion invested in the future of the Sprint-Clearwire merger, many companies are hedging their bets that WiMax will be a successful technology. While that has yet to be proven, any new, wireless broadband network will threaten AT&T's existing 3G and future 4G networks. But isn't a little competition what capitalism is all about?