LAS VEGAS (Reuters) - Nokia's N810 mobile Internet tablet will be one of the first devices designed for a new high-speed wireless network that Sprint Nextel Corp will launch commercially in April.

Nokia on Tuesday unveiled a version of the handheld device, which has a 4.13-inch touch screen, for WiMax -- the emerging wireless technology that Sprint is betting on for its next generation of high-speed services.

WiMax promises to blanket cities with mobile Web links that are five times faster than today's speeds. Like the first N810, which went on sale in the fall, the new version will also work on Wi-Fi, a short-range wireless technology used in hotspots such in coffee shops.

"The difference with WiMax is that you can move out of that hotspot," Mark Louison, head of Nokia's North American business, said in an interview ahead of the CTIA annual U.S. wireless show in Las Vegas.

Sprint, which has been seeking outside funding to expand WiMax beyond an initial three markets, has promised to open the network to a wide array of devices, such as music players or cameras, which consumers could buy from any store. The three initial markets are Chicago, Baltimore and Washington, D.C. Sprint has said it would have 10 WiMax devices at launch.

Nokia, the world's largest mobile phone maker, has trailed Motorola Inc and Samsung Electronics in the United States as it has won little business with U.S. carriers, which tightly control the phones that work on their networks.

There has been uncertainty about the U.S. future of WiMax. Sprint, which is losing customers from its existing service, has said it is re-examining its commitment to spend $5 billion on WiMax by 2010.

Sprint and Clearwire Corp, a smaller WiMax provider, are in talks to combine their WiMax assets in a venture with investment by other companies such as Comcast Corp, Intel Corp and Google Inc, sources familiar with the talks said last week.

Asked if Nokia would consider joining such a venture, Louison said: "Our business model is focusing on building devices and applications that run on devices ... We've never invested in an operator."

Even if the U.S. WiMax market evolves more slowly than expected, Louison said Nokia was confident it would find a market for the N810 overseas.

"WiMax is bigger than Sprint," he said.

The WiMax N810 will be available from Nokia's online store and its shops in New York and Chicago for $479, Nokia said.

(Editing by Maureen Bavdek)

© Reuters 2008 All rights reserved