Six months after a jury ruled that Microsoft infringed on a patent owned by Alcatel-Lucent, a federal judge has thrown the judgment out.

In what was the largest patent-related award ever recorded, Microsoft was fined $1.5 billion over its use of the digital music format MP3. Microsoft, whose Windows Media Player uses the MP3 standard in playing audio files, licenses the technology from a consortium led by the Fraunhofer Institute, a German research firm that helped create it with Bell Laboratories many years ago.

Bell Laboratories is now part of Alcatel-Lucent, which claims that two of the patents being used by Microsoft were developed by Bell Labs before it joined forces with Fraunhofer Institute.

The federal judge in San Diego said that one of the two patents is not being infringed upon by Microsoft, and the second one in question is partly owned by Fraunhofer, which was not part of the lawsuit.

Alcatel-Lucent said it plans to appeal. The judge said that if the telecommunications firm wins its appeal, he would order a retrial instead of reinstating the jury's verdict.

The case is being closely watched by many software makers that use the MP3 format, including Apple and RealNetworks.

Related links:

• Reuters: Judge Overturns $1.5 billion Ruling Against Microsoft 
• NYTimes: $1.5 Billion Verdict Against Microsoft is Set Aside