A Charlotte-based telecommunications company has raised an additional $3.58 million in a private debt offering, according to a filing Wednesday with the Securities and Exchange Commission.

Airwavz Solutions Inc. raised the money from 37 investors, according to the filing. The company raised $1.5 million in October 2016.

The company designs, develops, owns and operates wireless infrastructure platforms as a service for building owners.

Approximately 80 percent of mobile data consumption originates or terminates inside buildings, and only a small fraction of buildings have adequate wireless infrastructure, according to the company.

The company’s CEO is Brad Davis, a 25-year telecommunications and technology veteran with experience in corporate, private equity and early stage growth companies. He was named to that position in May.

Most recently, Davis served as CEO of ProctorFree, an online identity and machine learning company.

Davis is the former President and CEO of DukeNet Communications LLC, a regional fiber optic network company.

When named president in 2003, the business was in decline and valued at $45 million. By 2010, he led the sale of DukeNet at an enterprise value of $274 million, creating a joint venture with Alinda Capital Partners, a New York-based private equity firm.

Private companies similar to Airwavz Solutions, which rely on a Reg D exemption, aren’t required to register securities offerings with the SEC, but instead they must file a Form D electronically with the SEC after they sell the securities.