HELSINKI -- Qualcomm has filed a complaint against Nokia, accusing the world's largest maker of cellphones of infringing on six patents related to GSM technology.

The complaint, filed with to the U.S. International Trade Commission, asks for a ban on the import and sale of certain Nokia products.
Qualcomm said it expects the ITC investigation to start in July and for the case to be heard in the first half of next year.

In a press release, Nokia said it believed the patents were covered by a prior license agreement. The two companies are in negotiations about extending that agreement, which expires April 9, 2007.

"These repetitive legal actions, over GSM technologies that have been in the market for many years, reflect Qualcomm's concern over the current 3G UMTS patent negotiations," Nokia said.

GSM is the most used mobile phone system in the world.

It is the third legal action by Qualcomm against Nokia in the past eight months. Last month it accused Nokia of infringing on two other patents.