The Air Link

The air link is the mobile equivalent of what telcos call the last mile or local loop—the final connection between the customer and the network.The name is somewhat misleading because it doesn't refer to every part of the network carried over air.Most operators have some base stations that are connected to the main network via high-bandwidth fixed wireless beams, and these aren't considered part of the air link.

For an air link to function, it requires two radios, one carried around by a user and one connected permanently to the operator's network. These are known to technicians as the MSU and BTS, though users will think of them as the mobile phone and base station.