Patent ID: 8374108

Claim:
A mobile communication system comprising: a plurality of mobile units; and a plurality of base station units, wherein while at least one mobile unit of the plurality of mobile units is communicating with one base station unit of the plurality of base station units, the at least one mobile unit, prior to a handover and prior to monitoring of a radio access technology of another base station unit, notifies the one base station unit of the radio access technology to be monitored by the at least one mobile unit, the one base station unit decides a length of a period between durations during which the at least one mobile station receives data from the one base station unit, during which period the at least one mobile unit monitors the another base station unit, the length decision being made depending on the radio access technology notified by the at least one mobile unit, and depending on a predetermined rule, the at least one mobile unit stores the same predetermined rule considered by the one base station unit and also decides the length of the period, the length of the period decided by the at least one mobile unit thus being the same as the length decided by the one base station unit, the length decision at the at least one mobile unit being made depending on the radio access technology notified to the one base station unit, and depending on the predetermined rule, the length decided independently by each of the one base station unit and the at least one mobile unit, and the predetermined rule indicating that the length of the period is selected from a plurality of candidate lengths of the period, the candidate lengths including a first length corresponding to a first radio access technology and a second length corresponding to a second radio access technology, wherein the first length is shorter than the second length, the selection being made depending on the radio access technology to be monitored.