Rambus, a leading designer of memory and interface technologies, has sued IBM again in order to overturn the court ruling, which found that IBM did not infringe a patent that Rambus filed in 2002.

In a lawsuit filed on Monday in federal court in San Jose, California, Rambus said the U.S. Patent and Trademark Office (USPTO) made a mistake through a series of decisions in finding that a patent application assigned to IBM did not interfere with a Rambus patent obtained at the end of 2002, reports CNBC.

The USPTO's board of patent appeals and interferences ruled on the 24th of June that IBM did not infringe the patent that 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".

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

Rambus constantly accuses other companies of patent infringements in a bid to receive royalties. Interestingly, but IBM does not produce dynamic random access memory (DRAM) and only uses memory controllers in select devices. In particular, IBM uses Rambus XDR memory along with its PowerXCell 8i central processing units in select applications. The XDR use point-to-point links.

Tags: Rambus, IBM, XDR, DRAM, Business