Go to us patent office and go to search and type in Nokia as assignee. You get thousands and thousands of patents. Nokia makes patents and they have every right to sue. They are doing the innovating.
Edit: to comment below me
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That is legal stuff that is required to be posted on a press release having anything to do with stocks or future profit projections or just covering their arse in case.
If they make any kind of statement projecting profits or possible profits in a press release they have to include that legal small type as required. They are just covering their arse legally.

The real issue here is Nokia makes a crap load of patents, more than a lot of other Corps.
If you don't believe me then go to us patent office and type in Nokia as assignee name and see how many thousands of patents they have.

This is a valid legal argument. Nokia is a big Corp. with many employees making thousands of patents for the company. Someone has to start "stepping up" and claiming value for those patents that their employees have spent so much time on.
Think about it, what if you are an employee for Nokia and you spent so much time creating a new invention/patent for mobile devices or the technology that they use and then the attorney for the company does not step up and defend your patent or invention from other companies just taking it whenever they want to and selling millions of devices based on it.
Wouldn't you feel very betrayed?
I feel good that this guy is finally stepping up and defending his fellow employees hard work on patents.
I hope he does his/her job good and supports his company and fellow employees.