Base station
The radio equipment forming a cell in the mobile network — what the phone actually talks to.
The name shifts with each generation: NodeB in 3G, eNodeB in 4G, gNodeB in 5G. A station is typically split into three 120-degree sectors with separate antennas, tripling capacity against an omnidirectional design. The station manages the radio link, schedules which devices transmit when, and hands over to neighbouring cells as the user moves.
The architecture has been decomposed over time. Instead of all electronics at the mast base, the radio unit sits up the tower near the antenna — cutting cable losses — while baseband processing can be centralised in a data centre serving many sites.