Ericsson on Tuesday filed a lawsuit against Samsung for infringing its patents. The suit comes after the companies have spent nearly two years at the negotiating table in an attempt to reach an agreement on Samsung’s use of Ericsson’s patents, which fall under Fair Reasonable and Non-Discriminatory (FRAND) licensing terms.

Ericsson’s patents are seen as essential to several telecommunications and networking standards used by Samsung’s products, as well as other Ericsson patented inventions that are frequently implemented in wireless and consumer electronics products.

Ericsson said it has concluded that it has no option other than legal action after Samsung has refused all offers.

Samsung previously licensed Ericsson’s patents in 2001 and renewed in 2007, but its license has now expired.

“Ericsson has over 30,000 patents and more than 100 license agreements with all major players in the industry,” said Kasim Alfalahi, chief intellectual property officer at Ericsson. “Ericsson has tried long and hard to amicably come to an agreement with Samsung and to sign a license agreement on FRAND terms. We have turned to litigation as a last resort.”

Samsung said it has been more than fair and argues that it’s Ericsson being unreasonable at the bargaining table.

“This time, Ericsson has demanded significantly higher royalty rates for the same patent portfolio. As we cannot accept such extreme demands, we will take all necessary legal measures to protect against Ericsson’s excessive claims,” Samsung said in a statement provided to The New York Times.

Ericsson filed its complaint in the District Court for the Eastern District of Texas, which is the district where Ericsson’s U.S. headquarters is located.