This is the “base station subsystem”, which is used for radio broadcasting.
Mobiles communicate using base stations. Each base station is equipped with transmitter-receiver antennas and an electronic device which processes the signal.
Each station covers a specific area, hence the term cellular network. Several stations are centred on a single base station controller. This is the main control for the base station subsystem. It constantly monitors the quality of radio communication between the mobile and the antenna. If the mobile moves away from the antenna, the concentrator anticipates the movement and transfers the waves to another antenna.
When a call is received, the cellular tower converts the electromagnetic waves received from the mobile into digital data that are transmitted via the fixed network to the Backbone Network by copper wire, fibre, or radio waves. These mobile backhaul connections between the station and the backbone can be provided to mobile operators by Orange Wholesale France. This conversion happens in reverse when the call is dispatched.