The patent spat between Nokia and Qualcomm took another turn today when the Finnish mobile giant responded to the Qualcomm lawsuit filed in the Western District of Wisconsin on 2 April 2007.

Nokia said that it "remains confident" that its products do not infringe either of the two patents cited in the Qualcomm lawsuit, and further asserts that "both patents are invalid".

Nokia also filed patent counter assertions against Qualcomm for its alleged infringement of six Nokia implementation patents used in Qualcomm GSM/WCDMA and CDMA2000 chipsets.

Qualcomm has sought injunctions against Nokia in its previous litigation filings. Nokia said that it is therefore seeking damages and an injunction against Qualcomm's 'infringing' chipsets.

"Over the past 19 months Qualcomm has filed 11 patent litigation cases against Nokia seeking damages and injunctions," said Rick Simonson, chief financial officer at Nokia.

"Nokia has now filed its first counter action to address Qualcomm's unauthorised use of Nokia technology. We will continue to defend ourselves and exercise all rights according to our extensive intellectual property rights portfolio."

The implementation patents cited in the Nokia counterclaim relate primarily to multi-band/multi-mode technologies that allow transparent roaming for consumers.

It also covers direct conversion technologies that reduce handset and chipset size, cost and power consumption.

"These technologies have had a significant role in the success of Nokia devices. Qualcomm, through its unauthorised use of Nokia patents, has copied these innovations and made them available to its chipset customers," Nokia claimed.