The war between wireless communications giant Qualcomm and Finnish behemoth Nokia just got worse, with the latter countersuing its American rival for patent infringement.

At the same Western District of Wisconsin where Qualcomm had previously filed a suit against Nokia on April 2, Nokia responded with another lawsuit, stating that the company is “confident that its products do not infringe either of the two Qualcomm patents-in-suit and asserts that both patents are invalid.”

"Over the past 19 months Qualcomm has filed 11 patent litigation cases against Nokia seeking damages and injunctions," said Rick Simonson, chief financial officer, Nokia. "Nokia has now filed its first counter action to address Qualcomm's unauthorized use of Nokia technology. We will continue to defend ourselves and exercise all rights according to our extensive IPR portfolio."

Nokia’s patent suit refers to six Nokia implementation patents used in Qualcomm GSM/WCDMA and CDMA2000 chipsets. Although these patents do not influence in great manner the practice of standards, as Nokia admits, they provide according to the Finnish mobile behemoth substantial benefits when used. The implementation patents cited in the Nokia counterclaim filing relate primarily to multi-band/multi-mode technologies, that allow seamless and transparent roaming for consumers, and direct conversion technologies that reduce handset and chipset size, cost and power consumption.

In its previous litigation filings Qualcomm has sought injunctions against Nokia. Therefore, Nokia is seeking damages and also an injunction against Qualcomm's infringing chipsets.

Nokia implies that Qualcomm has copied without authorization the aforementioned technologies and illegally made them available to its chipset customers.