T-Mobile Northeast has sued the city of Wilmington and its Zoning Board of Adjustment in federal court over what the company called an unlawful denial of its application to build a rooftop extension on a senior living facility in order to improve wireless communications in the city.

The lawsuit, filed Monday in U.S. District Court for the District of Delaware, alleges that the board and the city violated the federal Communications Act when it rejected T-Mobile’s application following a public hearing on Oct. 26.