InterDigital Inc. said it will appeal a determination by the International Trade Commission which ruled that Nokia has not infringed on four InterDigital patents relating to Nokia 3G WCDMA handsets.

The ITC decision, issued late Friday, sent InterDigital stock reeling, down 20% in early trading Monday.

However, InterDigital said it would prepare an appeal to the ITC decision in the form of a petition to the full ITC commission for review of Friday's initial determination.

In a statement, Nokia's Ilkka Rahnasto said: "We believe this initial determination by the ITC combined with earlier U.K. court decisions provide a strong indication that the asserted value of InterDigital's 3G patent portfolio may have been overestimated." Rahnasto is vice president of Nokia's Legal and Intellectual Property unit.

As the wireless mobile phone business gains traction and moves to more robust service throughout the world, the industry has been racked with intellectual property disputes.

For instance, Research In Motion has paid hundreds of millions of dollars in IP and patent claims and is trying to obtain patent property from Nortel, which is being broken up under bankruptcy proceedings.

InterDigital noted that the patents involved in the ITC decision represent "a very small fraction of our total 3G portfolio."

"We currently hold and continue to receive patents covering inventions that we believe are essential to the 2G, 3G and emerging LTE standards," said InterDigital's president and chief executive officer William Merritt, in a statement. "We strongly disagree with (Friday's ITC) determination with respect to infringement."

In August, 2007, InterDigital filed a complaint with the ITC that certain Nokia products were being imported into the U.S. and that the products infringed on InterDigital U.S. patents.

Earlier voluminous patent litigation involving Nokia was settled last summer when the firm reached an agreement with Qualcomm in which the latter firm was paid a substantial sum of money in a 15-year deal.

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