I have iPhone 5S with 10.1.1 iOS and sometimes happens to me that I loose mobile data connection. In other words in top left corner on my screen there is provider (operator) and right next to it I usually have LTE. This LTE disappears from unknown reason (even in places that are 100% covered by LTE, but that is ok, I can accept it) but the problem is that it doesn't come back until I restart iPhone completely. I tried to restart data connection or some other things, but nothing worked. Only turning off and on again completely. Has anyone experienced this or have suggestions? Many thanks
This is probably not a problem with your phone. It is up to the carrier to decide which individual handsets are actually allowed on LTE on the current cell tower. So you might just be experiencing that your carrier hasn't got enough capacity to allow everyone on LTE, so they put you on a slower network.
So even though a coverage map tells you that LTE is available - it doesn't necessarily mean it is available to everyone.