Lucent sues Microsoft over Xbox tech

Lucent Technologies has filed a patent-infringement suit against Microsoft over the same MPEG-2 decoding technology at the center of a 2003 legal dispute.

According to the formal complaint, filed March 28 in a US District Court in San Diego, the telecommunications-equipment maker is suing Microsoft for patent infringement against Patent No. 5,227,878, titled "Adaptive Coding and Decoding of Frames and Fields of Video," which was issued to Lucent in 1993. The patent concerns MPEG-2 video encoding.

In 2003, Lucent filed infringement cases against Dell and Gateway over several patents, including No. 5,227,878. Because of its indemnity agreements with the companies Lucent was going after, Microsoft filed a countersuit against Lucent that same year.

Although Microsoft won several patent infringement claims on summary judgment, the claim concerning Patent No. 5,227,878 was dismissed without prejudice (meaning the lawsuit can be filed again if the problems are fixed) because of a typographical error in Lucent's patent.

"The judge dismissed the countersuit without prejudice, giving Lucent the opportunity to file for a patent correction, which we did," John Skalko, a spokesman for Lucent, told CNET News.com. "However, between the time of this original dismissal and our resubmission, there was another development. Microsoft issued the 360."

The typographical error in the patent concerned the phrase "compressed video bit stream," which has been corrected to read "compressed digital video bit stream and fields of compressed video bit stream."

The Certification of Correction to the patent that allowed the correct phrasing to be put back in was issued by the US Patent and Trademark Office in October 2005. The certification gives Lucent "the same effect and operation in law on the trial of actions for causes thereafter arising as if the same had been originally issued in such corrected form." According to the complaint filed by Lucent, the alleged infringement on this patent concerns the Xbox 360's "'out of the box' MPEG-2 decoding capability."

"The patent at issue is one that previously had been asserted by Lucent in connection with patent litigation between the parties since 2003. We're currently reviewing the complaint. Microsoft is an intellectual property company and we respect the intellectual property rights of others," Microsoft said in a statement.

Said Skalko, "We have a case. Otherwise it wouldn't be in court."

Lucent has requested a jury trial and is seeking an injunction against unauthorized use of the technology and unspecified damages.