"We made strong arguments supporting our view " said an Alcatel-Lucent spokeswoman.

Concerned

Microsoft said it had already licensed the MP3 technology, paying $16m to a German firm Fraunhofer.

"We are concerned that this decision opens the door for Alcatel-Lucent to pursue action against hundreds of other companies who purchased the rights to use MP3 technology from Fraunhofer, the industry-recognized rightful licensor," said Microsoft lawyer Tom Burt.

There are a number of long-running patent disputes between Microsoft and US-based Lucent Technologies which Alcatel is taking over - with a further five set to go to court.