MINNEAPOLIS (AP) — The University of Minnesota is suing the four largest wireless carriers in the U.S. over alleged patent infringement.

The university contends AT&T, Sprint, T-Mobile and Verizon are illegally using technology developed by a university professor to improve speed and reliability of 4G wireless-data service. The complaints were filed Wednesday in U.S. District Court in Minnesota.

The complaint refers to five patents that cover wireless communications innovations developed by University of Minnesota professor Georgios Giannakis and his co-inventors. The university contends Giannakis' work improves network reliability and performance.

AT&T, T-Mobile and Verizon declined to comment. Sprint did not respond to the newspaper's request for comment.