Industry speculation is swirling about why Nokia discontinued the WiMAX version of its N810 Internet Tablet.

The device launched in April last year and was successfully tested by Sprint Nextel for the carrier’s former Xohm network in Baltimore.  Sprint later transferred its Xohm business unit to Clearwire, which relaunched last month with a new brand called Clear.

Clearwire today said it never supported the Nokia device on its new mobile WiMAX networks, instead partnering with Motorola, various PC vendors and companies that plan to make Intel-based netbooks.  The new networks are unrelated to Clearwire’s legacy networks that use pre-WiMAX protocols.

But it is unclear if technical adjustments or the economy are part of Nokia’s reasoning.

“The end-of-life status of the WiMAX edition tablet does not apply to other WiMAX business development efforts that Nokia is involved in. Nokia will absolutely continue to work closely with… Clearwire with the same intensity as before and follow the WiMAX network developments,” spokeswoman Laurie Armstrong said.

“This is a business-as-usual decision. Moving forward, it is expected that by the timeframe when WiMAX networks are more widely deployed, refreshed products with even better performance will be required and we will continue to keep in lock step with those developments and opportunities,” she said.

Nokia, through Nokia Siemens Networks, also sells WiMAX base station equipment but lost a Sprint contract last fall in the Dallas area.  Sprint at the time said it selected Samsung hardware because of excess inventory, although speculation persists that Nokia had technical problems.

Industry analyst Doug Hyslop, of Wireless Strategy, emphasized the economy.  “It could very well be that the volumes weren’t there that they decided to pull the product.  I think it’s also a valid point that prod could only be sold in the Xohm markets,” he said.  Similarly, “It could be Nokia assumed there would be a faster migration of markets to true WiMAX and that may not be taking place given the financial markets.”