Patent ID: 7548519

Claim:
A mobile communication system for carrying out packet transmission/reception between a mobile terminal and a radio base station, comprising: a power saving unit for executing a power saving mode to reduce a power consumption at the mobile terminal; a packet classification judgement unit for judging a packet type of a packet; a sleep timer setting unit for setting a sleep timer value indicating a time duration since a last packet is transmitted/received until the power saving mode starts, according to a judgement result of the packet classification judgement unit; at least one sleep timer for measuring an elapsed time since the packet is transmitted/received; and a sleep execution unit for activating the sleep timer after the packet is transmitted/received, and controlling the power saving unit to execute the power saving mode at a timing at which the elapsed time measured by the at least one sleep timer exceeded the sleep timer value, wherein the at least one sleep timer includes a plurality of sleep timers such that when another packet of the packet type different from that of the packet is received during a measurement of the elapsed time for the packet, another sleep timer is activated to carry out a measurement of the elapsed time for the another packet; and the sleep execution unit controls the power saving unit to execute the power saving mode when all sleep timers are expired.