The legal battle between Nokia and Qualcomm further heated up on Monday as Nokia sued over patent infringement in the chipmaker's MediaFLO and BREW technologies.

Nokia's latest legal salvo is only one filing in a string of lawsuits and countersuits between the two sides. A cross-licensing deal expired on April 9, and the companies have since only intensified the fight against each other.

Chief Technology Officer Tero Ojanperd says that Nokia believes it has a strong case, and Qualcomm needs Nokia's technology in order to enable downloads in either product.

Qualcomm is also in the midst of fighting another legal battle with Broadcom, and has suffered a serious blow to its U.S. business interests after the US International Trade Commission ruled against it last week.

The ITC ruled that Qualcomm's chips infringe on Broadcom patents and banned the importation of all future phone models using the chip. Both the chipmaker and some of its allies are planning legal action to have the ruling blocked or overturned.

Over the past two years, Qualcomm has filed nearly a dozen suits against Nokia, although the phone manufacturer has only filed one lawsuit in return previous to Monday's suit. However, Nokia has attempted to place itself above the fray by publicly calling for the chipmaker to settle.

"We will continue to negotiate in good faith and want to resolve this as fast as possible. I think it is in everybody's interest to resolve this," Ojanpera told Reuters.