my son is in a hillbilly dorm. His room is on the lower level where there is no cell phone service. The school has free wire

There is only weak wifi and no 3or4G LTE for phone. He has to go across the pond to the fountain or drive to wallmart to make/receive phone calls. He can make wifi calls if it had a reliable signal. Ethernet ports no longer work.
 
The hotspot will still be limited by the weak wi-fi signal. Getting the school to add another router/access point in the dorm area would be a better long-term solution.

A micro-cell (thus the wireless carrier question), might be an option, if it can be connected to the school's network in the dorm.
 
No telling who the wireless is through, probably att. Hey, I think I've gotten the ap to work. It does so far at home, but I think the adapters are switched. I want the new antenna to catch the wrak signal, and the built-in adapter to share in the room. Will test in the dorm tomorrow.