Mobile communication system, mobile communication method, mobile terminal and base station

A mobile communication method for carrying out packet transmission/reception between a mobile terminal having a power saving mode to reduce a power consumption and a radio base station, comprising the steps of:

• (a) judging a packet type of a packet;
• (b) 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 step (a);
• (c) activating at least one sleep timer for measuring an elapsed time since the packet is transmitted/received;
• and
• (d) controlling the mobile terminal 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, the step (c) activates another sleep timer to carry out a measurement of the elapsed time for the another packet, and
• the step (d) controls the mobile terminal to execute the power saving mode when all sleep timers are expired.

A mobile terminal device for carrying out packet transmission/reception with a radio base station, comprising:

• a power saving unit for executing a power saving mode to reduce a power consumption at the mobile terminal device;
• 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.

A radio base station device for carrying out packet transmission/reception with a mobile terminal having a power saving mode to reduce a power consumption, comprising:

• 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 permission signal transmission unit for activating the sleep timer after the packet is transmitted/received, and transmitting a sleep permission signal for controlling the mobile terminal 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 permission signal transmission unit transmits the sleep permission signal when all sleep timers are expired.