Well yes but once you transmit from inside the building you can use the higher frequencies which are much more plentiful. And use many low power nodes similar to the way we deploy WiFi in offices, with one every 15 metres or so.

The bandwidth available at 26Ghz is huge and the low penetration means you dont need to have as much distance before you can reuse them again. A simple wall is already enough.

But no I didn't mean those old style signal boosters that basically just retransmit the analog signal.