Nokia has filed a complaint against Apple with the Federal District Court in the Western District of Wisconsin, alleging that iPhone and iPad 3G products infringe five of its patents.
In a short statement Nokia said the patents relate to 'technologies for enhanced speech and data transmission, using positioning data in applications and innovations in antenna configurations that improve performance and save space, allowing smaller and more compact devices.
'These patented innovations are important to Nokia's success as they allow improved product performance and design.'
Nokia's decision to sue Apple ups the stakes even further is a smartphone war that already this year has seen Apple sue HTC for infringing on 20 patents related to iPhone's 'user interface, underlying architecture and hardware'.
The fact that Nokia's action includes the iPad is hugely significant.
Paul Melin, General Manager, Patent Licensing at Nokia, said: "Nokia has been the leading developer of many key technologies in mobile devices. We have taken this step to protect the results of our pioneering development and to put an end to continued unlawful use of Nokia's innovation."
The statement added that Nokia has invested €40 billion in R&D over the last 20 years and owns over 11,000 patent families.