Sprint Nextel dropped out of the Next Generation Mobile Networks Alliance (NGMN) recently because the group endorsed LTE (Long Term Evolution) technology for 4G wireless networks, while Sprint is developing and nearly ready to launch competing WiMax networks this fall, a Sprint official said Thursday.

"Sprint was disappointed that NGMN shifted from its original technology-neutral stance," said Sprint spokesman John Polivka. "We respectfully withdrew our membership from the organization due to the change in direction."

Sprint was a founding member of NGMN, which started in 2006, and now has 18 mobile network operators from around the world, including several already committed to LTE, as members.

Officials at NGMN in Frankfurt, Germany, could not be reached to comment on Sprint's withdrawal.

A June 27 press release on the NGMN Web site describes an alliance between NGMN and the UMTS Forum and notes that LTE "is the first technology which broadly meets [NGMN] recommendations and is approved by the board."

Sprint had served on the NGMN board, staffed working committees and advocated NGMN's mission as an "advisory, technology agnostic organization," Polivka said. "A key tenet of the NGMN was technology neutrality."

LTE is expected to gain wide popularity globally in the next five years if only because it will provide an upgrade path for GSM networks that now predominate, analysts have noted.

However, Sprint has promoted WiMax widely in the U.S., and has joined with Clearwire Corp. and other investors to create a nationwide network. Some media services reported in June that Sprint CEO Dan Hesse had let it slip that a Baltimore launch of WiMax will occur in September, with Washington and Chicago markets launching by December. Polivka confirmed that September is the timeframe for a Baltimore launch, although no date or pricing or other details have been announced.

The Sprint withdrawal from NGMN provided Polivka with a chance to tout WiMax as a here-and-now next-generation wireless technology. He said 35 equipment makers are producing WiMax base stations and customer premises equipment, while more than 30 vendors are producing modems, PC cards and devices to run over WiMax networks. Also, 25 companies are building WiMax chipsets. Intel Corp. also unveiled its Centrino 2 quad-core processor, code-named Montevina on Monday, which operates over WiMax networks.