Your router is receiving signal from a LTE-A tower. Generally speaking the higher up and closer to a window, the better and stronger your signal will be.
Avoid placing your router behind a wall of metal, concrete, and believe it or not, trees and fish tanks (the water in these has an effect on signal).
Keep your modem away from things like microwaves, TV’s or anything with its own conflicting signal.
Check our coverage map to find out where you are in proximity to an LTE tower.
For a more in-depth look at getting better signal you can watch this video.