LoRa might enable this, and easily reaches 10-20km range (up to 100km in theory). A lot of projects in Europe experimenting with it: https://en.m.wikipedia.org/

LoRa might enable this, and easily reaches 10-20km range (up to 100km in theory). A lot of projects in Europe experimenting with it: https://en.m.wikipedia.org/wiki/LoRa https://en.m.wikipedia.org/wiki/LoRa