Aiming to boost its software revenue by inking deals and collecting royalties on its patents, BlackBerry Ltd. (BBRY) is taking it a step further, lodging a patent-infringement lawsuit against Nokia Corp. (NOK), the Finnish telecom giant.

According to a court filing reported on by Bloomberg, BlackBerry contends a slew of Nokia products use technology that BlackBerry says is covered by as many as 11 patents. Waterloo, Canada-based BlackBerry argues Nokia gives the mobile network products that infringe on BlackBerry’s patents to telecom providers like T-Mobile US Inc. (TMUS) and AT&T Inc. (T) for their wireless networks. In the court filing, BlackBerry said Nokia encourages the use of the products without a license from BlackBerry.

“BlackBerry seeks to obtain recompense for Nokia’s unauthorized use of BlackBerry’s patented technology,” the company said in the complaint, but it didn’t disclose how much it is seeking from Nokia. BlackBerry noted that Nokia knows the software company invented the technology Nokia is using, citing some of the patents in its own applications for patents.

Trying to Cash in on Software

According to Bloomberg, some of the patents in the lawsuit against Nokia come from Nortel Networks. Back in 2011, Rockstar Consortium, a group of companies including BlackBerry, bought Nortel’s patents for $4.5 billion after Nortel filed for bankruptcy. The group split up the patents with BlackBerry getting the ones that cover the mobile telecommunications standard 3GPP. BlackBerry said at the time it would be fair when it came it licensing the patents.  (See also: BlackBerry Consolidates Security Software Products.)

For BlackBerry, the lawsuit comes at a time when the once-dominant handset maker is shifting its focus to software, which has higher margins than its hardware business, which it outsourced this past fall. BlackBerry has been inking deals with companies to use its software. Earlier this month, BlackBerry announced it will allow software developers to build apps with some of its secure messaging and file-sharing software. In a press release announcing the new initiative, BlackBerry said developers will be able to integrate secure messaging, voice and video capabilities into apps and services. The BBM Enterprise Software Developer Kit will be available worldwide in February with a goal of competing with other cloud communications platforms. "We are constantly innovating and looking for ways to leverage our legacy and expertise in secure mobility to solve real business problems," said BlackBerry Chief Operating Officer Marty Beard in a statement at the time.