A cell phone coverage area is an area within which a cell phone can communicate wirelessly with a compatible base station to receive or make a telephone call. Conversely, a coverage hole is an area where a cell phone is unable to communicate with a base station.
Coverage areas differ by cell phone carrier, as some carriers may have not have base stations in certain locations. Multiple factors can affect cell phone coverage areas, including the surrounding terrain. For example, a hill may block a wireless signal trying to travel between a cell phone and base station.
There are also different types of coverage areas. In some areas, a cell phone carrier may have a voice base station but not a data base station. Such a location would be a voice coverage area, but a data coverage hole.