Sprint is planning to launch its WiMax networks in Chicago and Baltimore-Washington, D.C., within the week, according to Telephony magazine.

Sprint officials told Telephony that the soft launch will extend only to Sprint employees and is intended to prepare the networks for a broader trial early next year. At first, they will cover the downtown cores of Chicago, Baltimore and Washington but expand rapidly into the suburbs.

The industry has been waiting for Sprint Nextel to launch its network. Last year it committed to spending billions of dollars and rolling out a nationwide WiMax network. Earlier this year, it signed a letter of intent with Kirkland-based Clearwire to share the work and the costs, but that agreement fizzled. Since then, industry analysts have questioned Sprint's commitment, and the initiative seemed to be up in the air.

Sprint's launch of its WiMax service, called Xohm, will be the first high-profile release of true mobile WiMax technology.

Clearwire, founded by Craig McCaw, is often portrayed as the leader or the largest WiMax company because it already serves about 40 markets and has thousands of customers. However, it is not using the true mobile WiMax standard.

Clearwire is using proprietary equipment, and its equipment is not truly mobile. An Internet connection can't be handed off from one tower to the next while the user is in a car or on a train.

Clearwire and a partner, Intel, has been testing mobile WiMax in Portland, and is expected to upgrade its technology in existing markets over time.