New YorkThe Economic Times Sprint Nextel Corp announced a one-market launch of Xohm, its next generation high-speed wireless data service based on WiMax, with pay-per-day options as well as monthly service fees. The Monday launch in Baltimore, Maryland, comes before Sprint's expected completion in the fourth quarter of a venture with Clearwire Corp to build a larger network based on WiMax, which promises to blanket entire cities with wireless Internet access. Sprint, which has been working to stem customer losses from its existing services,...