cell (cellular) phone stems from the technology adopted, that divides
the ground to be covered by the signal into contiguous cells, with
an handshaking mechanism for passing over the signal from cell to cell
(from the transmitting antenna in the cell) while moving.
A general mobile phone of 'ancient times' established a connection to a
signal repeater (antenna), and when the connection was lost, due to distance, another connection needed to be reestablished, with a different repeater;
now the two words have the same meaning (in Italy we use cellulare, or 'telefonino' : small phone).