The intention of 4.9 GHz Public Safety is to support broadband applications, particularly mobile data and video. It can be used either as a direct medium or as back haul for another broadband medium such as 700 MHz LTE.
There are 3 main uses:
1) Point to point high speed backhaul (transport). E.g. data links for cameras, hotspots, phones/data.
2) Point to point telephone line replacement for radio sites. This is a low capacity use, but can be effective at replacing expensive or problematic phone line links for tower sites.
3) In a hotspot or mesh network configuration for mobile data type uses.(think of public safety WiFi).