AT&T has received permission from U.S. regulators to acquire airwaves from four companies including Comcast Corp. and San Diego Gas & Electric Co.

The Federal Communications Commission approved the acquisitions in an order posted on the agency’s website today. The approval also encompasses AT&T’s acquisition of airwaves from Horizon Wi-Com LLC and NextWave Wireless Inc., the FCC said in its order.

AT&T (NYSE: T), the second-largest U.S. wireless operator, has proposed at least 24 deals this year to acquire frequencies as it seeks to catch up with top mobile carrier Verizon Wireless, which is ahead in the race to stockpile the industry’s most precious asset. The companies involved told the FCC the spectrum is currently underutilized, the agency said.

Transferring the airwaves to Dallas-based AT&T will help boost mobile high-speed Internet use, the FCC said in its order. San Diego Gas & Electric had acquired the airwaves for smart grid use, the agency said.

The FCC approval will help “spur aggressive investment by AT&T and create good paying jobs across the wireless and technology eco-systems,” Joan Marsh, AT&T vice president of federal regulatory, said in a posting on the company’s public- policy blog.