WASHINGTON — The government took a big step Friday to aid the creation of new high-speed wireless Internet networks that could fuel the development of the next generation of smartphones, tablets and devices that have not even been thought of yet.

The Federal Communications Commission unanimously approved a sweeping, though preliminary, proposal to reclaim public airwaves currently used for broadcast television and auction them off for use in wireless broadband networks, with a portion of the proceeds paid to the broadcasters.

The initiative, which the FCC says would be the first in which any government would pay to reclaim public airwaves with the intention of selling them, would help satisfy what many industry experts say is booming demand for wireless Internet capacity.

Mobile broadband traffic will increase more than 30-fold by 2015, the commission estimates.