The University of Minnesota is suing the four largest wireless service providers in the United States, saying they are infringing on several university patents.

In the suit filed in U.S. District Court in Minnesota, the university says Verizon, AT&T, Sprint and T-Mobile are illegally using technology developed by a university professor that improves the speed and reliability of 4G LTE service. The university is asking the companies to pay a royalty for using the technology.

Representatives from all four carriers said they couldn't comment on the lawsuit.

The university said the technology involves five patents that cover wireless communications innovations developed by professor Georgios Giannakis and his co-inventors. The technology is part of the 4G LTE service that all four companies use and promote to their millions of customers nationwide, the university said.

"Every day, our faculty is developing life-changing inventions and cures for the common good; that is what a great research university does," university President Eric Kaler said. "We must vigorously protect our faculty, those discoveries and the overall interests of our university."

Giannakis holds an endowed chair in wireless communications, is the director of the university's Digital Technology Center, a professor in the department of electrical and computer engineering, and an internationally recognized expert in signal processing, communications and networking. He has received millions of dollars in public-sponsored research funding, including from the National Science Foundation and the U.S. Army.

Mary Lynn Smith