Aug 25, 2010 09:45 GMT  ·  By

Patent company Rambus, now well known for the many court actions it has filed against a variety of IT players, has once again taken it upon itself to sue IBM over alleged patent infringement, even though the U.S. Patent and Trademark Office (USPTO) already issued a ruling in the latter's favor.

Rambus is known for designing memory and interface technologies and already has an extensive patent portfolio.

For the most part, the company seals deals with designers of electronics products whenever they want to make use of a certain patent.

Other times, Rambus ends up trading barbs with various such companies, on the grounds that said makers of hardware are infringing its patents.

One of the most recently completed court actions, against IBM to be exact, was dismissed by USPTO (the U.S. Patent and Trademark Office).

The patent which acted as a pretext for that legal battle was obtained in late 2002 and concerns "a memory controller that communicates to at least one memory subsystem, with an independent point-to-point link used between the controller and each subsystem."

Oddly enough, IBM uses Rambus XDR memory, as well as PowerXCell 8i processors, only in select applications, as it does not actually produce DRAM itself. Still, the lawsuit was filed, though it was later dismissed.

The ruling was made on June 24 and established that IBM did not infringe this patent, but Rambus feels that the patent office made mistakes in its analysis of the situation and IBM's products.

The technology designer has now sued IBM again, in federal court in San Jose, California, hoping to overturn that ruling.

"The board committed errors of fact and law in its orders, decisions, and judgment," Rambus reportedly claimed.

This development is only the latest in a long string of legal moves meant to get companies to pay royalties.