Patent Publication Number: US-2015071148-A1

Title: State transition timer setting system, mobile equipment, mobile communication system, and state transition timer setting method

Description:
TECHNICAL FIELD 
     The present invention relates to a state-transition-timer setting system, a mobile equipment, a mobile communication system, and a state-transition-timer setting method for setting a state transition timer for a time after which a state of the mobile equipment is caused to transition from a communication state to a power-saving state. 
     BACKGROUND ART 
     The section of 15.6 of Non-Patent Literature 1 describes Fast Dormancy that is a function designed to reduce power consumption of a mobile equipment such as a mobile phone. 
     CITATION LIST 
     Non Patent Literature 
     
         
         [Non Patent Literature 1] Harri Holma, Antti Toskala, “WCDMA for UMTS: HSPA Evolution and LTE”, John Wiley &amp; Sons, Inc., 22 Sep. 2010 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     A mobile equipment to which the Fast Dormancy is applied causes a state of the mobile equipment to transition from a communication state to an idle state (power-saving state) after a timer (Fast Dormancy activation timer, referred to as “FD activation timer” hereinafter) for a certain time from completion of data communication elapses.  FIG. 1  includes diagrams illustrating time-series transitions of the state and the power consumption in the mobile equipment. In  FIG. 1 , the time T1 indicates a point in time when data communication is completed in the mobile equipment, the time T2 indicates a point in time when the FD timer expires, and the period T between the time T1 and the time T2 indicates a period of time of the FD activation timer. 
     As depicted in  FIG. 1A , the mobile equipment is initially in a communication state, and transitions from the communication state into an idle state at the time T2. As depicted in  FIG. 1B  illustrating the transition of power consumption of the mobile equipment on the same time series as in  FIG. 1A , the power consumption of the mobile equipment that has transitioned into the idle state is lower than the power consumption of the mobile equipment being in the communication state. 
     In other words, when the FD activation timer is set to a shorter time, the mobile equipment transitions into the idle state sooner after completing the data communication, and thus the power consumption of the mobile equipment can be reduced. However, when the mobile equipment is required to resume data communication due to new transmission or retransmission after transitioning into the idle state, the mobile equipment needs to transition from the idle state into the communication state, and accordingly time delay in data communication may occur associated with this transition. 
     In contrast, when the FD activation timer is set to a longer time, the mobile equipment maintains the communication state for a longer period of time after completing the data communication. When resumption of the data communication is required between the time T1 and the time T2 in  FIG. 1 , for example, due to new transmission or retransmission, the mobile equipment still remains to be in the communication state, and accordingly time delay in data communication does not occur associated with additional state transition and the connection time can be shortened. However, because the mobile equipment maintains the communication state for the longer period of time after completing the data communication, the power consumption of the mobile equipment cannot be significantly reduced. Thus, when the FD activation timer is set, a timer value needs to be set in consideration of the above-described trade-off. 
     The frequency of using communication in a mobile equipment is generally assumed to depend on a user or a situation, but no methods have been conventionally available for setting the FD activation timer that is suitable for all patterns. For example, in a case that the FD activation timer is shorter, when a mobile equipment frequently performs communication, delay problematically occurs every time the mobile equipment performs communication due to the transition from the idle state to the communication state. In addition, occurrence of traffic for the transition between a base station and a mobile equipment problematically puts a load on the network. In contrast, for example, in a case that the FD activation timer is longer, when time is left between the occurrence of traffic and the next communication is performed, an unnecessarily larger amount of electric power is problematically consumed during a period until the Fast Dormancy is activated. 
     The present invention has been made in view of such problems, and aims to provide a state-transition-timer setting system, a mobile equipment, a mobile communication system, and a state-transition-timer setting method that enable more efficient reduction of power consumption of the mobile equipment. 
     Solution to Problem 
     To solve the above-described problems, a state-transition-timer setting system according to one aspect of the present invention includes acquiring means for acquiring prediction information on the amount of traffic of a mobile equipment; timer determining means for determining a state transition timer for a time after which a state of the mobile equipment is caused to transition from a communication state to a power-saving state, based on the prediction information acquired by the acquiring means; and timer setting means for setting the state transition timer determined by the timer determining means for the mobile equipment. 
     A mobile equipment according to one aspect of the present invention includes acquiring means for acquiring prediction information on the amount of traffic of the mobile equipment; timer determining means for determining a state transition timer for a time after which a state of the mobile equipment is caused to transition from a communication state to a power-saving state, based on the prediction information acquired by the acquiring means; and timer setting means for setting the state transition timer determined by the timer determining means for the mobile equipment. 
     A mobile communication system according to one aspect of the present invention is a mobile communication system that includes a base station; and a mobile equipment. The base station includes acquiring means for acquiring prediction information on the amount of traffic of the mobile equipment; timer determining means for determining a state transition timer for a time after which a state of the mobile equipment is caused to transition from a communication state to a power-saving state, based on the prediction information acquired by the acquiring means; and transmitting means for transmitting the state transition timer determined by the timer determining means to the mobile equipment. The mobile equipment includes receiving means for receiving the state transition timer from the base station; and timer setting means for setting the state transition timer received by the receiving means for the mobile equipment. 
     A state-transition-timer setting method according to one aspect of the present invention is a state-transition-tinier setting method that is performed by a state-transition-timer setting system. The state-transition-timer setting method includes an acquiring step of, by acquiring means of the state-transition-timer setting system, acquiring prediction information on the amount of traffic of a mobile equipment; a timer determining step of, by timer determining means of the state-transition-timer setting system, determining a state transition timer for a time after which a state of the mobile equipment is caused to transition from a communication state to a power-saving state, based on the prediction information acquired at the acquiring step; and a timer setting step of, by timer setting means of the state-transition-timer setting system, setting the state transition timer determined at the timer determining step for the mobile equipment. 
     By the state-transition-timer setting system, the mobile equipment, the mobile communication system, and the state-transition-timer setting method described above, based on the prediction information on the amount of traffic of the mobile equipment acquired by the acquiring means, the state transition timer is determined by the timer determining means. The state transition timer thus determined is set for the mobile equipment by the timer setting means. With this configuration, based on the prediction information on the amount of traffic of the mobile equipment, the state transition timer can be dynamically determined and set. For example, when the prediction information indicates that the amount of traffic of the mobile equipment will increase, by setting the state transition timer to be longer and thus maintaining the mobile equipment to be in the communication state for a longer period of time after completion of data communication, time delay in data communication associated with additional state transition can be prevented from occurring at the time of resumption of data communication, whereby the connection time can be shortened. Furthermore, this can reduce the occurrence of traffic for transition between the base station and the mobile equipment, thereby reducing the load on the network. In addition, for example, when the prediction information indicates that the amount of traffic of the mobile equipment will decrease, by setting the state transition timer to be shorter for the mobile equipment to transition into the power-saving state sooner after the completion of data communication, the power consumption of the mobile equipment can be reduced. In this manner, it is possible to reduce the power consumption of the mobile equipment more efficiently while reducing the influence on the data communication. 
     In the state-transition-timer setting system, the mobile equipment, and the mobile communication system according to one aspect of the present invention, the prediction information may be past traffic amount that is the amount of traffic during a certain period of time in the past for the mobile equipment. The timer determining means may determine the state transition timer to be a longer time than a predetermined set time when the past traffic amount acquired by the acquiring means is larger than a predetermined threshold, and may determine the state transition timer to be a shorter time than the predetermined set time when the past traffic amount acquired by the acquiring means is smaller than the predetermined threshold. With this configuration, based on the past traffic amount, the state transition timer can be dynamically determined and set. For example, when the past traffic amount is larger than the predetermined threshold, the amount of upcoming traffic of the mobile equipment is predicted to be large, and accordingly by setting the state transition timer to be longer and thus maintaining the mobile equipment to be in the communication state for a longer period of time after completion of data communication, time delay in data communication associated with additional state transition can be prevented at the time of resumption of data communication, whereby the connection time can be shortened. Furthermore, this can reduce the occurrence of traffic for transition between the base station and the mobile equipment, thereby reducing the load on the network. In addition, for example, when the past traffic amount is smaller than the predetermined threshold, the amount of upcoming traffic of the mobile equipment can be predicted to be small, and accordingly by setting the state transition timer to be shorter for the mobile equipment to transition into the power-saving state sooner after the completion of data communication, the power consumption of the mobile equipment can be reduced. In this manner, it is possible to reduce the power consumption of the mobile equipment more efficiently while reducing the influence on the data communication. 
     In the state-transition-timer setting system, the mobile equipment, and the mobile communication system according to one aspect of the present invention, the prediction information may be activation information indicating whether a certain application involving communication is running in the mobile equipment. The timer determining means may determine the state transition timer to be a longer time than a predetermined set time when the activation information acquired by the acquiring means indicates that the application is running, and may determine the state transition timer to be a shorter time than the predetermined set time when the activation information acquired by the acquiring means indicates that the application is not running. With this configuration, based on the activation information, the state transition timer can be dynamically determined and set. For example, when the activation information indicates that the application is running, the amount of upcoming traffic of the mobile equipment can be predicted to be large, and accordingly by setting the state transition timer to be longer and thus maintaining the mobile equipment to be in the communication state for a longer period of time after completion of data communication, time delay in data communication associated with additional state transition can be prevented at the time of resumption of data communication, whereby the connection time can be shortened. Furthermore, this can reduce the occurrence of traffic for transition between the base station and the mobile equipment, thereby reducing the load on the network. In addition, for example, when the activation information indicates that the application is not running, the amount of upcoming traffic of the mobile equipment is predicted to be small, and accordingly by setting the state transition timer to be shorter for the mobile equipment to transition into the power-saving state sooner after the completion of data communication, the power consumption of the mobile equipment can be reduced. In this manner, it is possible to reduce the power consumption of the mobile equipment more efficiently while reducing the influence on the data communication. 
     In the state-transition-timer setting system, the mobile equipment, and the mobile communication system according to one aspect of the present invention, the state transition timer may be a time from when data communication of the mobile equipment is completed to when a transition request command to request transition into the power-saving state is transmitted to the base station, or may be a shortest transmission interval at which the mobile equipment is capable of transmitting the transition request command subsequently to when the mobile equipment transmits the transition request command after completion of data communication of the mobile equipment. By specifying the state transition timer in this manner, the time after which the state of the mobile equipment is caused to transition from the communication state to the power-saving state can be controlled more accurately, whereby the power consumption of the mobile equipment can be reduced more efficiently. 
     Advantageous Effects of Invention 
     The power consumption of a mobile equipment can be reduced more efficiently. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  includes diagrams illustrating time-series transitions of the state and the power consumption in a mobile equipment to which Fast Dormancy is applied. 
         FIG. 2  is a schematic diagram of a mobile communication system according to the embodiments of the present invention. 
         FIG. 3  is a functional block diagram illustrating a configuration of a mobile equipment according to a first embodiment of the present invention. 
         FIG. 4  is a diagram illustrating a hardware configuration of the mobile equipment according to the embodiments of the present invention. 
         FIG. 5  is a diagram illustrating a hardware configuration of a base station according to the embodiments of the present invention. 
         FIG. 6  is a diagram illustrating an example of state transition of the base station and the mobile equipment according to the embodiments of the present invention. 
         FIG. 7  is another example of the state transition of the base station and the mobile equipment according to the embodiments of the present invention. 
         FIG. 8  includes table examples of state-transition-timer determination tables according to the first embodiment of the present invention. 
         FIG. 9  includes other table examples of the state-transition-timer determination table according to the first embodiment of the present invention. 
         FIG. 10  is a sequence diagram illustrating processes of a state-transition-timer setting method performed in the mobile equipment according to the first embodiment of the present invention. 
         FIG. 11  is a functional block diagram illustrating a configuration of a mobile equipment according to a second embodiment of the present invention. 
         FIG. 12  includes table examples of state-transition-timer determination tables according to the second embodiment of the present invention. 
         FIG. 13  is a sequence diagram illustrating processes of a state-transition-timer setting method performed in the mobile equipment according to the second embodiment of the present invention. 
         FIG. 14  is a functional block diagram illustrating a configuration of a base station and a mobile equipment according to a third embodiment of the present invention. 
         FIG. 15  is a sequence diagram illustrating processes of a state-transition-timer setting method performed in the base station and the mobile equipment according to the third embodiment of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of a state-transition-timer setting system, a mobile equipment, a mobile communication system, and a state-transition-timer setting method will be described in detail hereinafter with reference to the drawings. In the drawings, like reference signs are given to like elements, and duplicated explanations are omitted. 
       FIG. 2  is a schematic diagram of a mobile communication system  3  including a base station  2  and a mobile equipment  1  according to the present embodiments. As depicted in  FIG. 2 , the mobile communication system  3  includes the base station  2  and the mobile equipment  1 . The numbers of base stations  2  and mobile equipments  1  included in the mobile communication system  3  depicted in  FIG. 2  each are one, but are not limited to this, and the base station  2  and the mobile equipment  1  each may be provided in plurality. The base station  2  and the mobile equipment  1  can wirelessly communicate with each other in mobile communication. 
     The mobile communication system  3 , the base station  2 , and the mobile equipment  1  specifically correspond to the Universal Mobile Telecommunications System (UMTS), the Base Transceiver Station (BTS), and the User Equipment (UE), respectively, in the 3rd Generation Partnership Project (3GPP) standard. The base station  2  may be the Radio Network Controller (RNC) that is a radio control station in the 3GPP standard, or may be a device that has functions of both the BTS and the RNC. The mobile communication system  3 , the base station  2 , and the mobile equipment  1  also correspond to the Evolved Packet System (EPS), the Evolved Node B (eNodeB), and the UE, respectively, in the 3GPP standard. 
     First Embodiment 
       FIG. 3  is a functional block diagram illustrating a configuration of a mobile equipment  1 A according to a first embodiment. As depicted in  FIG. 3 , the mobile equipment  1 A includes a transmitting/receiving unit  10 A, a past-traffic-amount storage unit  11 A, a measuring unit  12 A, an acquiring unit  13 A (acquiring means), a timer determining unit  14 A (timer determining means), and a timer setting unit  15 A (timer setting means). The acquiring unit  13 A, the timer determining unit  14 A, and the timer setting unit  15 A are also components of the status-transition-timer setting system (not depicted). In other words, part of the respective functional blocks constituting the state-transition-timer setting system is included by the mobile equipment  1 A, and the other part is included by another device (e.g., base station  2 ). 
     The mobile equipment  1 A is constructed of hardware such as a CPU.  FIG. 4  is a diagram illustrating one example of a hardware configuration of the mobile equipment  1 . The mobile equipment  1 A depicted in  FIG. 3  is physically configured as a computer system that includes a CPU  100 , a RAM  101  and a ROM  102  being main memories, an input/output device  103  such as a numeric keypad or a display, a communication module  104 , and an auxiliary storage  105  as depicted in  FIG. 4 . 
     Functions of the respective functional blocks of the mobile equipment  1 A depicted in  FIG. 3  are implemented by loading predetermined computer software into hardware such as the CPU  100  and the RAM  101  depicted in  FIG. 4  to operate the input/output device  103 , the communication module  104 , and the auxiliary storage  105  under control of the CPU  100 , and also by reading and writing data from and into the RAM  101 . 
     It should be noted that a mobile equipment  1 B and a mobile equipment  1 C described in the following embodiments each are also configured as a computer system that is similar to the mobile equipment  1 A. In the present embodiment, mobile equipments of the respective embodiments are collectively called the mobile equipment  1 . 
       FIG. 5  is a diagram illustrating one example of a hardware configuration of the base station  2 . The base station  2  depicted in  FIG. 2  is physically configured as a computer system that includes a CPU  200 , a RAM  201  and a ROM  202  being main memories, an input/output device  203  such as a numeric keypad or a display, a communication module  204 , and an auxiliary storage  205  as depicted in  FIG. 5 . 
     Functions of the respective functional blocks of a base station  2 C illustrated in  FIG. 14  described later are implemented by loading predetermined computer software into hardware such as the CPU  200  and the RAM  201  depicted in  FIG. 5  to operate the input/output device  203 , the communication module  204 , and the auxiliary storage  205  under control of the CPU  200 , and also by reading and writing data from and into the RAM  201 . In the present embodiments, base stations of the respective embodiments are collectively called the base station  2 . 
     The following describes the respective functional blocks of the mobile equipment  1 A (or the state-transition-timer setting system) depicted in  FIG. 3 . 
     The transmitting/receiving unit  10 A transmits and receives data between the mobile equipment  1 A and another device such as the base station  2 . The past-traffic-amount storage unit  11 A measures the amount of traffic (amount of data communication) transmitted and received by the transmitting/receiving unit  10 A, and stores the data in the auxiliary storage  105 , for example. 
     The measuring unit  12 A creates prediction information on the amount of upcoming traffic of the mobile equipment  1 A. Specifically, the measuring unit  12 A measures past traffic amount that is the amount of traffic in the mobile equipment  1 A during a certain period in the past to create a measurement result (past traffic amount) on the basis of the amount of traffic of the mobile equipment  1 A that is stored by the past-traffic-amount storage unit  11 A. Examples of the past traffic amount measured by the measuring unit  12 A include the amount of traffic during the past 10 seconds, the amount of traffic during the past 30 seconds, and the amount of traffic during the past 60 seconds. The measuring unit  12 A may cause the past-traffic-amount storage unit  11 A to store therein the past traffic amount thus created. 
     The acquiring unit  13 A acquires prediction information on the amount of upcoming traffic of the mobile equipment  1 A. Specifically, the acquiring unit  13 A acquires the past traffic amount measured by the measuring unit  12 A from the past-traffic-amount storage unit  11 A or the measuring unit  12 A. The acquiring unit  13 A may acquire the past traffic amount (prediction information) from an external device via a network. 
     The timer determining unit  14 A determines a state transition timer for a time after which the state of the mobile equipment  1 A is caused to transition from a communication state to a power-saving state on the basis of the prediction information acquired by the acquiring unit  13 A. Specifically, the timer determining unit  14 A determines the state transition timer to be a longer time than a predetermined set time when the past traffic amount acquired by the acquiring unit  13 A is larger than a predetermined threshold, and determines the state transition timer to be a shorter time when the past traffic amount acquired by the acquiring unit  13 A is smaller than the predetermined threshold. 
     A specific example of the power-saving status (idle status) will be herein described. In the 3GPP standard, as the Radio Resource Control (RRC) state transitions, the RRC Connected Mode and the RRC Idle Mode are specified, and further in the RRC Connected Mode, the CELL_Dedicated Channel (DCH) state, the CELL_Forward Access Channel (FACH) state, the Cell Paging Channel (CELL_PCH) state, and the URA Paging Channel (URA_PCH) state are specified. The power-saving state in the present embodiments is any one or more states of the RRC Idle Mode, the CELL_FACH state, the CELL_PCH state, and the URA_PCH state. 
     The CELL_PCH state herein is a state in which no dedicated channel is assigned to the UE, the UE intermittently receives the Paging Channel via the Paging Indication Channel (PICH) in the Downlink and has no channel for the Uplink. Note that the UMTS Terrestrial Radio Access Network (UTRAN) knows the position of the UE on cell level. 
     Subsequently, a specific example of the state transition timer will be described with reference to  FIG. 6 .  FIG. 6  is a diagram illustrating an example of state transition of the mobile equipment  1  and the base station  2  on the time series. To begin with, communication data is generated in the mobile equipment  1  at time T10, and accordingly the mobile equipment  1  and the base station  2  transition into the communication state and the data is communicated between the mobile equipment  1  and the base station  2 . This data communication is then completed at time T11, an FD activation timer that is a timer for a certain time (period of time indicated by the arrow A) is activated after the completion of the data communication, and the FD activation timer expires at time T12. Then, the mobile equipment  1  transmits a Signaling Channel Release Indication (SCRI) message that is a radio release request to the base station  2  at time T12, and in response to this, the base station  2  transmits a command to transition into the power-saving state to the mobile equipment  1  at time T13, and the mobile equipment  1  receives this transition command at time T14. As for the SCRT, see Section 8.1.14 in the following reference literature 1, for example.
     [Reference Literature 1: 3GPP TS 25.331 V11.0.0 (2011-12)]   

     The mobile equipment  1  and the base station  2  then transition from the communication state into the power-saving state at time T14. Next, communication data is generated again in the mobile equipment  1  at time T15, and accordingly the mobile equipment  1  and the base station  2  transition into the communication state and the data is communicated between the mobile equipment  1  and the base station  2 . This data communication is completed at time T16, and the point in time when the FD activation timer expires from the time T16 is assumed to be time T17. 
     It is assumed herein that the mobile equipment  1  is a T323 timer that is a shortest transmission interval of the SCRI from the base station  2  is set for the mobile equipment  1 . The T323 timer, specified in the 3 GPP, is the minimum value of an interval between two SCRI messages that the mobile equipment  1  is allowed to transmit. In  FIG. 6 , when the period (arrow B) between the time T12 and time T18 is set to be the T323 timer, the mobile equipment  1  cannot transmit an SCRI message during the period between the time T12 and the time T18. Subsequently, the mobile equipment  1  transmits the SCRI message to the base station  2  at the time T18, and in response to this, the base station  2  transmits a command to transition into the power-saving state to the mobile equipment  1  at time T19, and the mobile equipment  1  receives this transition command at time T20. 
     The state transition timer includes either one of a time from when data communication of the mobile equipment  1  is completed to when a transition request command to request transition into the power-saving state is transmitted to the base station  2 , or a shortest transmission interval at which the mobile equipment  1  can transmit the transition request command subsequently to when the mobile equipment  1  transmits the transition request command after completion of the data communication of the mobile equipment  1 . In other words, the state transition timer includes either one of the FD activation timer (period indicated by the arrow A in  FIG. 6 ) or the T323 timer (period indicated by the arrow B in  FIG. 6 ). Similarly to the period T depicted in  FIG. 1 , the period from the time T11 when the data communication is completed to the time T14 when the mobile equipment  1  transitions into the power-saving state in  FIG. 6  may be the FD activation timer. 
     It has been described in  FIG. 6  that the mobile equipment  1  transitions from the communication state into the power-saving state at the time T14 when receiving the command to transition into the power-saving state from the base station  2 , but it is not limited to this.  FIG. 7  is a diagram illustrating another example of the state transition of the mobile equipment  1  and the base station  2  on the time series. As depicted in  FIG. 7 , the mobile equipment  1  may transition from the communication state into the power-saving state at the time T12 when transmitting the SCRI message. 
     The following describes specific processes by which the timer determining unit  14 A determines the state transition timer on the basis of the past traffic amount with reference to  FIGS. 8 and 9 . Specific examples of the “predetermined threshold” to which the timer determining unit  14 A compares the past traffic amount include “0 MB of data communication occurring during the past 60 seconds”, “10 KB of data communication occurring during the past 60 seconds”, and “5 MB of data communication occurring during the past 10 seconds”. Specific examples of the “predetermined set time” include a default value (e.g., 10 seconds) of the FD activation timer when the state transition timer is the FD activation timer, and a default value (e.g., 60 seconds) of the T323 timer when the state transition timer is the T323 timer.  FIGS. 8A and 8B  each are diagrams illustrating table examples of state-transition-timer determination tables to which the timer determining unit  14 A refers when determining the state transition timer.  FIG. 8A  illustrates a state-transition-timer determination table when the state transition timer is the FD activation timer, and  FIG. 8B  illustrates a state-transition-timer determination table when the state transition timer is the T323 timer. As depicted in  FIG. 8 , times to which the timer determining unit  14 A refers when determining the time for the state transition timer are stored in the state-transition-timer determination tables. 
     For example, assuming that the predetermined threshold is “0 MB of data communication occurring during the past 60 seconds (communication has not occurred during the past 60 seconds)” and the state transition timer is the FD activation timer, when the past traffic amount is “5 MB of data communication occurring during the past 60 seconds”, the past traffic amount is larger than the predetermined threshold, and thus the timer determining unit  14 A refers to the state-transition-timer determination table of  FIG. 8A  and determines the FD activation timer to be “15 seconds” that is a longer time than the predetermined set time. 
     Alternatively, assuming that the predetermined threshold is “5 MB of data communication occurring during the past 10 seconds” and the state transition timer is the T323 timer, when the past traffic amount is “1 MB of data communication occurring during the past 10 seconds”, the past traffic amount is smaller than the predetermined threshold, and thus the timer determining unit  14 A refers to the state-transition-timer determination table of  FIG. 8B  and determines the T323 timer to be “10 seconds” that is a shorter time than the predetermined set time. 
     As another example, when the past traffic amount acquired by the acquiring unit  13 A indicates that communication has consecutively occurred at an interval within three seconds, for example, during the past 30 seconds, the timer determining unit  14 A may determines the state transition timer to be a shorter time than the predetermined set time. When the past traffic amount indicates that communication has not consecutively occurred, the timer determining unit  14 A may determines the state transition timer to be a longer time than the predetermined set time. 
       FIG. 9  includes diagrams illustrating other table examples of the state-transition-timer determination tables. A two-stage structure of times to which the timer determining unit  14 A refers is illustrated in  FIG. 8 , and a multiple-stage structure is illustrated in  FIG. 9 . Similarly to  FIG. 8 ,  FIG. 9A  illustrates a state-transition-timer determination table when the state transition timer is the FD activation timer, and  FIG. 9B  illustrates a state-transition-timer determination table when the state transition timer is the T323 timer. In the multiple-stage structure in  FIG. 9 , a range of a predetermined threshold and a time are associated with each other for each stage. For example, in  FIG. 9A , the range of a predetermined threshold “equal to or larger than 0 MB and smaller than 1 MB in data communication occurring during the past 60 seconds” and the time of “2 seconds”, the range of a predetermined threshold “equal to or larger than 1 MB and smaller than 2 MB in data communication occurring during the past 60 seconds” and the time of “8 seconds”, the range of a predetermined threshold “equal to or larger than 2 MB and smaller than 5 MB in data communication occurring during the past 60 seconds” and the time of “12 seconds”, and the range of a predetermined threshold “equal to or larger than 5 MB in data communication occurring during the past 60 seconds” and the time of “30 seconds” are associated with each other. The timer determining unit  14 A then determines a time associated with a predetermined threshold to which the past traffic amount acquired by the acquiring unit  13 A corresponds as the state transition timer. For example, in the case of  FIG. 9A  described above, when the past traffic amount acquired by the acquiring unit  13 A is “3 MB of data communication during the past 60 seconds”, the timer determining unit  14 A determines the FD activation timer to be “12 seconds” that corresponds to the range of the predetermined threshold “equal to or larger than 2 MB and smaller than 5 MB in data communication occurring during the past 60 seconds” in  FIG. 9A . 
     Referring back to  FIG. 3 , the timer setting unit  15 A sets (reflects, updates) the status transition timer determined by the timer determining unit  14 A for the mobile equipment  1 A. The status transition timer is set by the timer setting unit  15 A, so that the status transition timer takes effect in the mobile equipment  1 A. When the status transition timer takes effect in the mobile equipment  1 A, the state of the mobile equipment  1 A transitions from the communication state to the power-saving state on the basis of the state transition timer. 
     The following describes processes of the state-transition-timer setting method in the mobile equipment  1 A (or the state-transition-timer setting system) according to the present embodiment with reference to  FIG. 10 . 
     To begin with, the measuring unit  12 A measures the past traffic amount (step SA 1 ), and the acquiring unit  13 A acquires the past traffic amount thus measured (step SA 2 , acquiring step). Next, the timer determining unit  14 A determines whether the past traffic amount is larger than the predetermined threshold (step SA 3 , timer determining step). If the past traffic amount is not determined to be larger at step SA 3 , the timer determining unit  14 A determines the state transition timer to be a shorter time than the predetermined set time (step SA 4 , timer determining step). If the past traffic amount is determined to be larger at step SA 3 , the timer determining unit  14 A determines the state transition tinier to be a longer time than the predetermined set time (step SA 5 , timer determining step). Subsequently to step SA 4  and step SA 5 , the timer setting unit  15 A sets the state transition timer determined (step SA 6 , timer setting step). 
     The following describes functions and effects of the mobile equipment  1 A (or the state-transition-timer setting system) configured as in the first embodiment. 
     With the mobile equipment  1 A (or the state-transition-timer setting system) of the present embodiment, based on the prediction information on the amount of traffic of the mobile equipment  1 A acquired by the acquiring unit  13 A, the state transition timer is determined by the timer determining unit  14 A. The state transition timer thus determined is set for the mobile equipment  1 A by the timer setting unit  15 A. With this configuration, based on the prediction information on the amount of traffic of the mobile equipment  1 A, the state transition timer can be dynamically determined and set. For example, when the prediction information indicates that the amount of traffic of the mobile equipment  1 A will increase, by setting the state transition timer to be longer and thus maintaining the mobile equipment  1 A to be in the communication state for a longer period of time after completion of data communication, time delay in data communication associated with additional state transition can be prevented from occurring at the time of resumption of data communication without leaving ongoing Transmission Control Protocol (TCP) retransmission of data unfinished, whereby the connection time can be shortened. Furthermore, this can reduce the occurrence of traffic for transition between the base station  2  and the mobile equipment  1 A, thereby reducing the load on the network. In addition, for example, when the prediction information indicates that the amount of traffic of the mobile equipment  1 A will decrease, by setting the state transition timer to be shorter for the mobile equipment  1 A to transition into the power-saving state sooner after the completion of data communication, the power consumption of the mobile equipment  1 A can be reduced. In this manner, it is possible to reduce the power consumption of the mobile equipment  1 A more efficiently while reducing the influence on the data communication. 
     With the mobile equipment  1 A (and the state-transition-timer setting system) of the present embodiment, the prediction information may be the past traffic amount that is the amount of traffic during a certain period of time in the past for the mobile equipment  1 A. The timer determining unit  14 A may determine the state transition timer to be a longer time than the predetermined set time when the amount of the past traffic acquired by the acquiring unit  13 A is larger than the predetermined threshold, and may determine the state transition timer to be a shorter time than the predetermined set time when the amount of the past traffic acquired by the acquiring unit  13 A is smaller than the predetermined threshold. With this configuration, based on the amount of the past traffic, the state transition timer can be dynamically determined and set. For example, when the past traffic amount is larger than the predetermined threshold, the amount of upcoming traffic of the mobile equipment  1 A is predicted to be large, and accordingly by setting the state transition timer to be longer and thus maintaining the mobile equipment  1 A to be in the communication state for a longer period of time after completion of data communication, time delay in data communication associated with additional state transition can be prevented at the time of resumption of data communication, whereby the connection time can be shortened. Furthermore, this can reduce the occurrence of traffic for transition between the base station  2  and the mobile equipment  1 A, thereby reducing the load on the network. In addition, for example, when the past traffic amount is smaller than the predetermined threshold, the amount of upcoming traffic of the mobile equipment  1 A can be predicted to be small, and accordingly by setting the state transition timer to be shorter for the mobile equipment  1 A to transition into the power-saving state sooner after the completion of data communication, the power consumption of the mobile equipment  1 A can be reduced. In this manner, it is possible to reduce the power consumption of the mobile equipment  1 A more efficiently while reducing the influence on the data communication. 
     With the mobile equipment  1 A (and the state-transition-timer setting system) of the present embodiment, the state transition timer may be a time (FD activation timer) from when data communication of the mobile equipment  1 A is completed to when a transition request command to request transition into the power-saving state is transmitted to the base station  2 , or may be a shortest transmission interval (T323 timer) at which the mobile equipment  1 A can transmit the transition request command subsequently to when the mobile equipment  1 A transmits the transition request command after completion of data communication of the mobile equipment  1 A. By specifying the state transition timer in this manner, the time after which the state of the mobile equipment  1 A is caused to transition from the communication state to the power-saving state can be controlled more accurately, whereby the power consumption of the mobile equipment  1 A can be reduced more efficiently. 
     Second Embodiment 
     The following describes a mobile equipment  1 B according to a second embodiment with reference to  FIGS. 11 to 13 .  FIG. 11  is a functional block diagram illustrating a configuration of the mobile equipment  1 B according to the second embodiment. As depicted in  FIG. 11 , the mobile equipment  1 B includes an application monitoring unit  16 B, an acquiring unit  13 B (acquiring means), a timer determining unit  14 B (timer determining means), and a timer setting unit  15 B (timer setting means). The acquiring unit  13 B, the timer determining unit  14 B, and the timer setting unit  15 B are also components of the status-transition-timer setting system (not depicted). In other words, part of the respective functional blocks constituting the state-transition-timer setting system is included by the mobile equipment  1 B, and the other part is included by another device (e.g., base station  2 ). 
     The following describes the respective functional blocks of the mobile equipment  1 B (or the state-transition-timer setting system) depicted in  FIG. 11 . 
     The application monitoring unit  16 B monitors applications that are running in the mobile equipment  1 B to determine whether a certain application involving communication is running. Specific examples of the certain application involving communication include an application having a video chat function. The application monitoring unit  16 B then creates activation information (prediction information) indicating whether the certain application involving communication is running. 
     The acquiring unit  13 B acquires the activation information created by the application monitoring unit  16 B. The acquiring unit  13 B may acquire the activation information from an external device via a network. 
     The timer determining unit  14 B determines the state transition timer to be a longer time than a predetermined set time when the activation information acquired by the acquiring unit  13 B indicates that the application is running, and determines the state transition timer to be a shorter time than the predetermined set time when the activation information acquired by the acquiring unit  13 B indicates that the application is not running. 
     The following describes specific processes by which the timer determining unit  14 B determines the state transition timer on the basis of the activation information with reference to  FIG. 12 .  FIG. 12  includes table examples of state-transition-timer determination tables to which the timer determining unit  14 B refers when determining the state transition timer. As depicted in  FIG. 12 , contents indicated by the activation information and times are associated with each other and stored in the state-transition-timer determination tables.  FIG. 12A  illustrates a state-transition-timer determination table when the state transition timer is the FD activation timer, and  FIG. 12B  illustrates a state-transition-timer determination table when the state transition timer is the T323 timer. 
     For example, assuming that the state transition timer is the FD activation timer, when the activation information acquired by the acquiring unit  13 B indicates that the application is running, the timer determining unit  14 B refers to the state-transition-timer determination table of  FIG. 12A  and determines the FD activation timer to be an infinite time (the maximum time that the mobile equipment  1  can set) that is a longer time than the predetermined set time (e.g., 10 seconds as default) (or determines not to activate the Fast Dormancy). 
     Alternatively, assuming that the state transition timer is the T323 timer, when the activation information acquired by the acquiring unit  13 B indicates that the application is not running, the timer determining unit  14 B refers to the state-transition-timer determination table of  FIG. 12B  and determines the T323 timer to be 10 seconds that is a shorter time than the predetermined set time (e.g., 60 seconds as default). 
     The timer setting unit  15 B is similar to the timer setting unit  15 A, and thus description thereof is omitted. 
     The following describes processes of a state-transition-timer setting method in the mobile equipment  1 B (or the state-transition-timer setting system) according to the present embodiment with reference to  FIG. 13 . 
     To begin with, the application monitoring unit  16 B monitors applications that are running to create activation information (step SB 1 ). The acquiring unit  13 B then acquires the activation information thus created (step SB 2 , acquiring step). Next, the timer determining unit  14 B determines whether the activation information acquired indicates that a certain application involving communication is running (step SB 3 , timer determining step). If it is determined at step SB 3  that the activation information does not indicate that the application is running, the timer determining unit  14 B determines the state transition timer to be a shorter time than the predetermined set time (step SB 4 , timer determining step). If it is determined at step SB 3  that the activation information indicates that the application is running, timer determining unit  14 B determines the state transition timer to be a longer time than the predetermined set time (step SB 5 , timer determining step). Subsequently to step SB 4  and step SB 5 , the timer setting unit  15 B sets the state transition timer determined (step SB 6 , timer setting step). At step SB 5 , the mobile equipment  1 B may determine not to activate the Fast Dormancy instead of determining the state transition timer to be the longer time than the predetermined set time. 
     The following describes functions and effects of the mobile equipment  1 B (or the state-transition-timer setting system) configured as in the second embodiment. 
     With the mobile equipment  1 B (and the state-transition-timer setting system) of the present embodiment, the prediction information may be activation information indicating whether a certain application involving communication is running in the mobile equipment  1 B. The timer determining unit  14 B may determine the state transition timer to be a longer time than a predetermined set time when the activation information acquired by the acquiring unit  13 B indicates that the application is running, and may determine the state transition timer to be a shorter time than the predetermined set time when the activation information acquired by the acquiring unit  13 B indicates that the application is not running. With this configuration, based on the activation information, the state transition timer can be dynamically determined and set. For example, when the activation information indicates that the application is running, the amount of upcoming traffic of the mobile equipment  1 B can be predicted to be large, and accordingly by setting the state transition timer to be longer and thus maintaining the mobile equipment  1 B to be in the communication state for a longer period of time after completion of data communication, time delay in data communication associated with additional state transition can be prevented at the time of resumption of data communication, whereby the connection time can be shortened. Furthermore, this can reduce the occurrence of traffic for transition between the base station  2  and the mobile equipment  1 B, thereby reducing the load on the network. In addition, for example, when the activation information indicates that the application is not running, the amount of upcoming traffic of the mobile equipment  1 B is predicted to be small, and accordingly by setting the state transition timer to be shorter for the mobile equipment  1 B to transition into the power-saving state sooner after the completion of data communication, the power consumption of the mobile equipment  1 B can be reduced. In this manner, it is possible to reduce the power consumption of the mobile equipment  1 B more efficiently while reducing the influence on the data communication. 
     Third Embodiment 
     The following describes a mobile communication system  3 C including a base station  2 C and a mobile equipment  1 C according to a third embodiment with reference to  FIGS. 14 and 15 .  FIG. 14  is a functional block diagram illustrating a configuration of the base station  2 C and the mobile station  1 C according to the third embodiment. As depicted in  FIG. 14 , the base station  2 C includes a transmitting/receiving unit  20 C, a past-traffic-amount storage unit  21 C, a measuring unit  22 C, an acquiring unit  23 C (acquiring means), a timer determining unit  24 C (timer determining means), and a transmitting unit  25 C (transmitting means). The mobile equipment  1 C includes a receiving unit  17 C (receiving means) and a timer setting unit  15 C (timer setting means). The acquiring unit  23 C, the timer determining unit  24 C, and the timer setting unit  15 C are also components of the status-transition-timer setting system (not depicted). In other words, part of the respective functional blocks constituting the state-transition-timer setting system is included by the base station  2 C, and the other part is included by the mobile equipment  1 C. 
     The following describes the respective functional blocks of the base station  2 C and the mobile equipment  1 C (or the state-transition-timer setting system) depicted in  FIG. 14 . 
     The transmitting/receiving unit  20 C of the base station  2 C transmits and receives data between the base station  2 C and the mobile station  1 C. The past-traffic-amount storage unit  21 C measures the amount of traffic (amount of data communication) transmitted and received by the transmitting/receiving unit  20 C and stores the data in the auxiliary storage  205 , for example. 
     The measuring unit  22 C creates prediction information on the amount of upcoming traffic of the mobile equipment  1 C. Specifically, the measuring unit  22 C measures past traffic amount that is the amount of traffic in the mobile equipment  1 C during a certain period in the past to create a measurement result (past traffic amount) on the basis of the amount of traffic of the mobile equipment  1 C that is stored by the past-traffic-amount storage unit  21 C. Examples of the past traffic amount measured by the measuring unit  22 C are similar to those of the past traffic amount measured by the measuring unit  12 A in the first embodiment. 
     The acquiring unit  23 C acquires prediction information on the amount of upcoming traffic of the mobile equipment  1 C. Specifically, the acquiring unit  23 C acquires the past traffic amount measured by the measuring unit  22 C. The acquiring unit  23 C may acquire the past traffic amount (prediction information) from an external device via a network. 
     The timer determining unit  24 C determines a state transition timer (an FD activation timer or a T323 timer) for a time after which the state of the mobile equipment  1 C is caused to transition from a communication state to a power-saving state on the basis of the prediction information acquired by the acquiring unit  23 C. Because the details of the timer determining unit  24 C are similar to those of the timer determining unit  14 A in the first embodiment, description thereof is omitted. 
     The transmitting unit  25 C transmits the state transition timer determined by the timer determining unit  24 C to the mobile equipment  1 C. 
     The receiving unit  17 C of the mobile equipment  1 C receives the state transition timer from the base station  2 C. Specifically, the mobile equipment  1 C receives the state transition timer transmitted by the transmitting unit  25 C of the base station  2 C. 
     The timer setting unit  15 C sets (reflects, updates) the state transition timer received by the receiving unit  17 C for the mobile equipment  1 C. The status transition timer is set by the timer setting unit  15 C, so that the status transition timer takes effect in the mobile equipment  1 C. When the status transition timer takes effect in the mobile equipment  1 C, the state of the mobile equipment  1 C transitions form the communication state to the power-saving state on the basis of the state transition timer. 
     The following describes processes of the state-transition-timer setting method in the mobile communication system  3 C (or the state-transition-timer setting system) according to the present embodiment with reference to  FIG. 15 . 
     To begin with, the measuring unit  22 C of the base station  2 C measures the past traffic amount (step SC 1 ), and the acquiring unit  23 C acquires the past traffic amount thus measured (step SC 2 ). Next, the timer determining unit  24 C determines whether the past traffic amount is larger than the predetermined threshold (step SC 3 ). If the past traffic amount is not determined to be larger at step SC 3 , the timer determining unit  24 C determines the state transition timer to be a shorter time than the predetermined set time (step SC 4 ), If the past traffic amount is determined to be larger at step SC 3 , the timer determining unit  24 C determines the state transition timer to be a longer time than the predetermined set time (step SC 5 ). Subsequently to step SC 4  and step SC 5 , the transmitting unit  25 C transmits the state transition timer thus determined to the mobile equipment  1 C (step SC 6 ). 
     Next, the receiving unit  17 C of the mobile equipment  1 C receives the state transition timer (step SC 7 ), and the timer setting unit  15 C sets the state transition timer thus received (step SC 8 ). 
     The following describes functions and effects of the mobile communication system  3 C (or the state-transition-timer setting system) configured as in the third embodiment. 
     With the mobile communication system  3 C (or the state-transition-timer setting system) according to the present embodiment, the past traffic amount is stored and the state transition timer is determined on the side of the base station  2 C. As is apparent from comparison between the mobile equipment  1 A of the first embodiment and the mobile equipment  1 C of the present embodiment, the configuration of the mobile equipment  1 C is simplified, and the processing load of storing and measuring the past traffic amount and determining the state transition timer, for example, and the storage capacity required therefor are reduced. This can more efficiently reduce the power consumption of the mobile equipment  1 C. 
     In the mobile equipment  1  configured as in the first embodiment to the third embodiment, a user may be notified of the measured amount of traffic, the communication status of applications, and the amount of consumed current, for example, displayed with icons, for example. 
     REFERENCE SIGNS LIST 
       1 ,  1 A,  1 B,  1 C . . . mobile equipment,  2 ,  2 C . . . base station,  3  . . . mobile communication system,  10 A . . . transmitting/receiving unit,  11 A . . . past-traffic-amount storage unit,  12 A . . . measuring unit,  13 A,  13 B . . . acquiring unit,  14 A,  14 B . . . timer determining unit,  15 A,  15 B,  15 C . . . timer setting unit,  16 B . . . application monitoring unit,  17 C . . . receiving unit,  20 C . . . transmitting/receiving unit,  21 C . . . past-traffic-amount storage unit,  22 C . . . measuring unit,  23 C . . . acquiring unit,  24 C . . . timer determining unit,  25 C . . . transmitting unit