The working of cellular phone depend on zones or small base stations called cells. As a user moves from one area to other or a cell, the call is handed off from the old to a new cell.

In case of satellite phones, there is no concept of cells or cell towers. The most popular hand held satellite telephones use Low Earth Orbiting (LEO) satellites. When one turns on the satellite phone the signal goes up to any number of satellites in a compatible constellation where it is then registered with the constellation.