How does your phone stay connected while you move?

Your phone stays connected because the land is split into cells, and the network hands your call from one cell's tower to the next as you move. A cellular network is a wireless network spread over land areas called cells, each served by at least one fixed base station. The design allows seamless handover, enabling uninterrupted communication when a device moves from one cell to another.

Why cells instead of one huge tower? A single transmitter can handle only one transmission on a given frequency. But a cell typically uses a different set of frequencies from its neighbours, to avoid interference, and those frequencies can be reused in other cells that are not adjacent. The same frequency can serve many links at once, one in each of several cells, so the network has more capacity than one large transmitter. Your phone also uses less power because the tower is close.

The handover is the clever part. In a primitive taxi radio system, the driver moved away from one tower and closer to another and had to switch frequency by hand. In a cellular system, the switch to the new cell's frequency is done electronically, without interruption and without manual switching.

Cells are small: in cities a cell site may reach about half a mile, in rural areas as much as 5 miles. 5G is the fifth and current generation, and like earlier systems it divides areas into cells. Compared with 4G, it is designed for higher data rates, more capacity and lower latency.