Handset maker Sony Ericsson is suing Clearwire for trademark infringement over the WiMAX operator's "confusingly similar" logos.

In a complaint filed with the U.S. District Court for the Eastern District of Virginia, Sony Ericsson said Clearwire's logos are so similar to its own that it constituted trademark infringement.

Sony Ericsson called Clearwire's logo "confusingly similar." Both logos feature a silver-white sphere with a green swirl.

Sony Ericsson's concerns over Clearwire's logos date back to 2009, when the company learned Clearwire had filed trademark applications for a sphere with a swirl logo in green and white, with the colors in a reverse configuration from Sony Ericsson's.

Sony Ericsson contested the trademark application and Clearwire agreed to stop using the "reverse image logo" and abandoned its trademark applications. Despite its agreement to cease using the logo, Clearwire continued to use its nearly identical logo in its advertising, prompting Sony Ericsson to file suit.

The lawsuit comes as Clearwire prepares to launch its first smartphone, though its plans have been delayed by funding problems. Sony Ericsson is concerned that a Clearwire-branded smartphone will exacerbate consumer's confusion about the logos.

"Unless enjoined, Defendants' current and announced conduct will confuse customers and cause irreparable harm to Sony Ericsson," the company argued in its lawsuit.

Clearwire declined to comment on the lawsuit.