Mobile carriers in the US have been telling the Federal Communications Commission (FCC) for months that they're in a bad way—450MHz of total spectrum just isn't enough to keep up with consumer demand for wireless services. As the companies explained in various FCC filings over the summer, the current strain on their networks is caused by a veritable data tsunami that has swept the country in the last few years, and they want the government to make more spectrum available to solve the problem.

The big driver of mobile data use has been smartphones. Put an iPhone, Pre, BlackBerry, or Android handset in the hands of someone who previously made only voice calls and sent a few text messages, and data use skyrockets.

According to T-Mobile, users of its G1 Android-powered phone use 50 times the data of average T-Mobile customers. The Wireless Communications Association International (WCAI) says that smartphone users consume 30 times the data of a "traditional" handheld device. And AT&T told the FCC that its wireless network has seen a "5,000 percent growth in data usage" over the last three years, thanks in large part to the iPhone. AT&T says it is rolling out 2,000 additional cell towers in 2009 to meet demand.

WCAI also endorsed the following data projection from Cisco that shows the relative amount of data used in a month by the typical phone, smartphone, and laptop user on a wireless data network.

Two different approaches to the issue have been pitched to the FCC. On one side are the carriers, who want more licensed spectrum and point out that many other countries are busy freeing up spectrum for use by mobile operators.

On the other side are public interest groups and think tanks like the New America Foundation, Public Knowledge, and the Media Access Project. They argue that spectral efficiency can and should improve, saying that "less than 20 percent of the frequency bands below 3GHz were in use over the course of a business day." These groups have already supported more uses in these prime frequencies, including "white spaces broadband" which has already been approved by the FCC.

Given the overwhelming number of complaints about spectrum availability, the FCC has put out a special request for information (PDF) on what it might do to ease the crunch; its answers will be incorporated into the National Broadband Plan currently being drawn up at the agency.

Nothing that happens at the FCC will bring more spectrum onto the market for at least a few years, but the agency last year did auction off prime chunks of the 700MHz spectrum opened up by the DTV transition (the biggest national chunk was grabbed by Verizon). In addition, it allowed white space devices to operate in the UHF part of the TV band, provided no channel or wireless mic is transmitting on that frequency. A Microsoft-funded study recently concluded that this alone could generate $15 billion a year in value.