Cellular Mobile Communication System -4.Hand-Over
There are cases in which a mobile unit traverses multiple cells of a cellular mobile communications system during a call.
This demands the use of "hand-over"; the radio channel is switched over automatically to the appropriate cell during the call. Excessive signal interference can trigger "interference channel switchover" will select and switch the signal over to a radio channel within the same cell with less interference.
Previously, communications would be cut off if radio waves could not reach certain sites during a call such as near the entrance/exit of a tunnel. Communications would also be cut if radio signals were received from a cell station that was not recognised as an adjacent cell.
The "re-connection hand-over" system, which was introduced in Digital Mova Hyper, memorizes the radio channel being used so that the connection can be rapidly restored after temporary outages.
Switching Channels During a Phone Call