My Cisco router connect to the IP5 five storeys down in a elevator as well.. only when I have exit out of the elevator on floor 1 does it actually go off wifi and instantly to LTE ...
In the driveway should have good signal not on the borderline unless your router is at the other end of a mansion
A word of advice, move your router to a part of your house which is nearer to the driveway and problem solved !
I bought airport extreme to extend my time capsule network for just that reason, now i get wifi perfectly in my driveway but when i drive away it takes a few seconds to turn off but the way i look at it is if i am driving i shouldnt be searching the web anyway, but not having it in the driveway is understandable.