Research in Motion (RIM) and Motorola are embroiled in a series of legal battles, with both firms claiming the other is infringing upon its patents. RIM filed suit in the US District Court for the Northern District of Texas last Saturday, alleging that Motorola is engaging in anti-competitive conduct by demanding overly high fees for the licensing of several Motorola patents, currently being used by RIM. These include patents such as WiFi access for mobile devices. RIM says Motorola is violating previous agreements to license its technology on “reasonable” terms and is also alleging that its own patents, including one for a mobile device with a thumb-driven interface, are being infringed by Motorola.

Reacting to RIM’s claim, a Motorola spokeswoman said, “We have not yet reviewed the complaint but based on our understanding of the matter we believe their claims are entirely without merit and Motorola intends to vigorously defend itself.” The Canadian company’s filing came one day after Motorola filed a suit against RIM, claiming it violated some of Motorola’s own patents.