Clearwire launched its mobile Internet service in Washington, D.C., and plans to expand that footprint in coming months.

It also launched service in Kansas City, Kan., and expanded its 4G network in Baltimore. The company says its network is now in 34 markets covering about 44 million people.

Clear uses WiMax, a wireless 4G technology and promises fast average mobile download speeds.

In the nation's capital, the service "covers nearly 1 million people in communities as far north as Chevy Chase and Silver Spring, Md., south to Alexandria, Va., west to Falls Church, Va., and east to College Park, Md." It published a coverage map.

WiMax critics meantime continue to cite competitive developments that they think show the future is in Long-Term Evolution (LTE).

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