Telecom equipment maker Ericsson has filed another set of patent infringement lawsuits against Apple over royalty payment for use of 5G wireless patents in iPhones.
Both companies have already sued each other in the United States as negotiations failed over the renewal of a seven-year licensing contract for telecom patents first struck in 2015, Reuters reported.

Ericsson sued first in October claiming that Apple was trying to improperly cut down the royalty rates while the iPhone maker filed a lawsuit in December accusing the Swedish company of using strong-arm tactics to renew patents.

“Since the prior agreement has expired, and we have been unable to reach agreement on the terms and scope of a new license, Apple is now using our technology without a license,” an Ericsson spokesman said.

The Swedish company invests about $5 billion every year in research, has a portfolio of more than 57,000 patents, and royalties from its patent portfolio account for roughly a third of its operating profit.

Last year Ericsson settled patent lawsuits with smartphone maker Samsung after several months of court battles that temporarily hit its quarterly earnings.