AT&T plans to test 5G in combination with the AirGig fixed broadband technology that the carrier developed in house. The 5G AirGig plans came to light in an AT&T policy paper in which the carrier also said it had “initiated discussions with technology suppliers” about testing and building commercial-grade AirGig equipment.
AT&T has been testing its AirGig technology to provide gigabit broadband connectivity for several years. The technology is designed for deployment on powerline infrastructure but is considerably different from the broadband powerline technology that failed to find commercial success a decade or so ago. More details here.
RC Wireless has a detailed description of the technology as it existed in 2017. AirGig solves the need for fiber backhaul networks. It also addresses some other thorny 5G issues by eliminating the need for mini towers by using the existing telephone and power poles. By using existing poles, it will be possible to extend the service into rural areas, going where ever the power/telephone grid exists. Of course, there is a cost and return on investment factor that will be part of any rural extension decision.