Google escalated a fight with Sonos Inc. over the wireless home speaker market, filing a lawsuit that alleges patent infringement.

The conflict between the two companies erupted in January when Sonos, which is competing with cheaper speakers from Google and Amazon.com Inc., sued Google for infringing its patents.

“Sonos has made false claims about the companies’ shared work and Google’s technology in the lawsuits,” the Alphabet Inc. unit said in a complaint filed Thursday in San Francisco federal court. “While Google rarely sues other companies for patent infringement, it must assert its intellectual property rights here.”

Sonos, the Santa Barbara-based pioneer of wireless speakers, is using Google’s patented technology for search, software, networking, audio processing and digital-media management and streaming, while refusing to pay a license, according to the lawsuit.

Sonos didn’t immediately respond to an email seeking comment on the lawsuit.

According to the Sonos lawsuit, the dispute started in 2013, when it inked a deal to work on a Google music service. At the time, Sonos wasn’t expecting Google to build its own wireless audio devices. When Google did, the search-engine giant copied key features, such as synchronized playback, Sonos said. The dispute culminated when Google released the Home Max in 2017, a smart speaker that incorporates Sonos’s features at a lower price, according to the lawsuit.

The case is Google LLC v. Sonos Inc., 20-cv-3845, U.S. District Court, Northern District of California (San Francisco).