Mobile-phone companies, chipmakers, device manufacturers and software developers will need to spend about $200 billion a year in research and capital expenses to get there.

And engineers will have to find ways to get the technology to work around interference from trees and rain and provide a strong enough signal to handle the anticipated demand.

AT&T says it has laid the groundwork for 5G through network upgrades in 23 cities and fixed wireless trials in Kalamazoo, Michigan; South Bend, Indiana; Waco and Austin Texas.