The mobile phone business is nothing more than a dogfight at this point, as you can see from Andy Cotgreave's simple but beautiful viz on telecoms lawsuits. One clear pattern he has shown is that companies with declining revenue are more apt to sue. No surprise there!
About this Viz
Nokia, which one could argue has the most to lose in the business, seems to be suing the most. You know what they say: if you cant beat them, sue them.