Abstract:
A wireless communication device including: a plurality of antennas configured to perform a plurality of wireless communication protocols simultaneously, and a processor configured to obtain each of a plurality of power consumptions for each of the plurality of the wireless communication protocols, to obtain each of a plurality of communication throughput for each of the plurality of the wireless communication protocols, to calculate an aggregated communication efficiency of the wireless communication using the plurality of wireless communication protocols simultaneously based on the plurality of the power consumptions and the plurality of the communication throughput, and to control the plurality of the antennas, when the aggregated communication efficiency exceeds a given value, as to perform the plurality of wireless communication protocols simultaneously, and, when the aggregated communication efficiency is equal to or less than the given value, as to stop one of the plurality of wireless communication protocols.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2012-001605, filed on Jan. 6, 2012, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The embodiments discussed herein are related to a wireless communication device and a wireless communication method. 
     BACKGROUND 
     It is known link aggregation (LA) as a technique for achieving the same communication throughput as wired communication in wireless communication. Wireless communication in LA is performed by using multiple communication protocols such as the long term evolution (LTE) and the wireless fidelity (WiFi) (trademark) at the same time. 
     In this type of LA, communication throughput of wireless communication may be increased as more communication protocols are used. However, the power consumption for wireless communication increases when more communication protocols are used. 
     It is known a technique to reduce power consumption for wireless communication by selecting the communication protocol having the best communication efficiency among a plurality of communication protocols. For example, there is a technique in which the power consumption and the communication throughput for each communication protocol is obtained, and an amount of power consumption per bit is calculated as communication efficiency on the basis of the power consumptions and communication throughputs so that the communication protocol with the lowest amount of power consumption per bit is selected. 
     The related-art techniques have been disclosed in Japanese Laid-open Patent Publication No. 2009-88976 and No. 2011-55124. 
     SUMMARY 
     According to an aspect of the invention, a wireless communication device including: a plurality of antennas configured to perform a plurality of wireless communication protocols corresponding to a plurality of wireless communication systems simultaneously, and a processor configured to obtain each of a plurality of power consumptions for each of the plurality of the wireless communication protocols, to obtain each of a plurality of communication throughput for each of the plurality of the wireless communication protocols, to calculate an aggregated communication efficiency of the wireless communication using the plurality of wireless communication protocols simultaneously based on the plurality of the power consumptions and the plurality of the communication throughput, and to control the plurality of the antennas, when the aggregated communication efficiency exceeds a given value, as to perform the plurality of wireless communication protocols simultaneously, and, when the aggregated communication efficiency is equal to or less than the given value, as to stop one of the plurality of wireless communication protocols. 
     The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  illustrates a configuration of a mobile station according to a first embodiment. 
         FIG. 2  is a flow chart of processing by the mobile station according to the first embodiment. 
         FIG. 3  illustrates a configuration of a mobile station according to a second embodiment. 
         FIG. 4  is a flow chart of processing by the mobile station according to the second embodiment. 
         FIG. 5  illustrates a configuration of a mobile station according to a third embodiment. 
         FIG. 6  is a flow chart of processing by the mobile station according to the third embodiment. 
         FIG. 7  illustrates a configuration of a mobile station according to a fourth embodiment. 
         FIG. 8  describes a correspondence relation of remaining battery capacity and a threshold. 
         FIG. 9  is a flow chart of processing by the mobile station according to the fourth embodiment. 
         FIG. 10  illustrates a configuration of a mobile station according to a fifth embodiment. 
         FIG. 11  is a flow chart of processing by the mobile station according to the fifth embodiment. 
         FIG. 12  illustrates a configuration of a mobile station according to a sixth embodiment. 
         FIG. 13  is a flow chart of processing by the mobile station according to the sixth embodiment. 
         FIG. 14  illustrates a configuration of a mobile station according to a seventh embodiment. 
         FIG. 15  is a flow chart of processing by the mobile station according to the seventh embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     However, according to the above conventional art, only one communication protocol having the lowest power consumption per bit may be selected. That is, in the conventional art, performing communication control using a plurality of communication protocols at the same time with regard to communication efficiency is not considered. As a result, there is a problem in the conventional art in that although an increase in power consumption may be suppressed, high communication throughput are not attained. 
     In consideration of the above problem, it is an object of the embodiments discussed herein to provide a wireless communication device and a wireless communication method that are able to suppress increases in power consumption. 
     The following is a detailed explanation of an embodiment of the wireless communication device and the wireless communication method disclosed hereinbelow with reference to the accompanying drawings. The embodiments are not limited to the features disclosed herein. For example, although the following embodiments describe a mobile station as an example of a wireless communication device, the embodiments are not limited as such and may refer to a wireless communication device equipped with a wireless communication function that uses a plurality of communication protocols at the same time. 
     Embodiment 1 
     First, an explanation of a mobile station according to a first embodiment will be provided.  FIG. 1  illustrates a configuration of a mobile station according to the first embodiment. As illustrated in  FIG. 1 , a mobile station  100  according to the first embodiment includes an LTE wireless communication unit  110 , a WiFi wireless communication unit  120 , a wireless control unit  130 , an IP packet processing unit  140 , an application processing unit  150 , and a main control unit  160 . The mobile station  100  is described as being equipped with the LTE wireless communication unit  110  and the WiFi wireless communication unit  120  as wireless communication units using two different communication protocols. However, the mobile station  100  may be equipped with two or more wireless communication units using a plurality of communication protocols. 
     The LTE wireless communication unit  110  performs wireless communication of various types of data with an LTE base station in compliance with the LTE communication. Specifically, the LTE wireless communication unit  110  includes a radio frequency (RF) unit  111  and an LTE wireless processing unit  112 . 
     The RF unit  111  performs digital/analog (D/A) conversion, performs up-converting from a baseband frequency to a wireless frequency, and amplifies electrical power with an amplifier to transmit uplink signals from an antenna  111   a . The RF unit  111  performs down-converting from a wireless frequency to a baseband frequency on downlink signals received from the antenna  111   a , and performs A/D conversion. 
     The LTE wireless processing unit  112  adds retransmission information to IP packet data, performs multilevel modulation and error correction code addition, and generates uplink signals. The LTE wireless processing unit  112  performs decoding of the error correction codes and demodulation on the downlink signals. 
     The WiFi wireless communication unit  120  performs wireless communication of various types of data with a WiFi base station in compliance with the WiFi communication. Specifically, the WiFi wireless communication unit  120  includes a RF unit  121  and a WiFi wireless processing unit  122 . 
     The RF unit  121  performs digital/analog (D/A) conversion, performs up-converting from a baseband frequency to a wireless frequency, and amplifies electrical power with an amplifier to transmit uplink signals from an antenna  121   a . The RF unit  121  performs down-converting from a wireless frequency to a baseband frequency on downlink signals received from the antenna  121   a , and performs A/D conversion. 
     The WiFi wireless processing unit  122  adds retransmission information to IP packet data, performs multilevel modulation and error correction code addition, and generates uplink signals. The WiFi wireless processing unit  122  performs decoding of the error correction codes and demodulation on the downlink signals. 
     The wireless control unit  130  is connected to the LTE base station and controls the wireless communication of various types of data with an LTE base station in compliance with the LTE communication by controlling the LTE wireless communication unit  110 . The wireless control unit  130  is connected to a WiFi base station and controls the wireless communication of various types of data with a WiFi base station in compliance with the WiFi communication by controlling the WiFi wireless communication unit  120 . The wireless control unit  130  has a pre-stored policy for adding a connection to a WiFi base station in compliance with the WiFi communication after connecting to an LTE base station in compliance with the LTE communication. 
     The wireless control unit  130  executes wireless communication using the LTE communication and the WiFi communication at the same time according to an instruction from a below mentioned communication control unit  164 . For example, the wireless control unit  130  sorts IP packets with sequence numbers added thereto to the LTE wireless communication unit  110  and the WiFi wireless communication unit  120  after the sequence numbers that indicate the order of transmitting data are added to the IP packet data. For example, the wireless control unit  130  collects IP packets with the sequence numbers added thereto from the LTE wireless communication unit  110  and the WiFi wireless communication unit  120 , and rearranges the order of the IP packet data on the basis of the sequence numbers added to the collected IP packets. 
     The wireless control unit  130  disconnects wireless communication using either of the communication among the LTE communication and the WiFi communication and executes wireless communication using the remaining communication according to an instruction from the communication control unit  164 . For example, the wireless control unit  130  sorts IP packet data with sequence numbers added thereto to only the LTE wireless communication unit  110  if the wireless communication using the WiFi communication is disconnected. For example, the wireless control unit  130  collects IP packet data with the sequence numbers added thereto from only the LTE wireless communication unit  110 , and rearranges the order of the IP packet data on the basis of the sequence numbers added to the collected IP packet data. 
     The IP packet processing unit  140  removes destination IP address information from the IP packet data obtained from the wireless control unit  130 , and outputs the IP packet data to the application processing unit  150 . The IP packet processing unit  140  adds destination IP address information to the IP packet data obtained from the application processing unit  150 , and outputs the IP packet data to the wireless control unit  130 . 
     The application processing unit  150  uses the IP packet data obtained from the IP packet processing unit  140  to execute certain applications. For example, the application processing unit  150  plays moving image data when the IP packet data is moving image data, or displays still image data on a display and the like when the IP packet data is still image data. 
     The main control unit  160  controls the wireless communication using the LTE communication and the WiFi communication at the same time (hereinbelow referred to as “synchronized wireless communication”) by controlling the wireless control unit  130 . The main control unit  160  includes a power consumption obtaining unit  161 , a communication throughput obtaining unit  162 , a communication efficiency calculating unit  163 , and the communication control unit  164 . 
     The power consumption obtaining unit obtains power consumption of each wireless communication protocol according to the communication s. Specifically, the power consumption obtaining unit  161  obtains the power consumption of the wireless communication being performed in compliance with the LTE communication by the LTE wireless communication unit  110 . The power consumption obtaining unit  161  obtains the power consumption of the wireless communication being performed in compliance with the WiFi communication by the WiFi wireless communication unit  120 . Hereinbelow, wireless communication being performed in compliance with the LTE communication by the LTE wireless communication unit  110  will be referred to as “wireless communication using the LTE communication.” Hereinbelow, wireless communication being performed in compliance with the WiFi communication by the WiFi wireless communication unit  120  will be referred to as “wireless communication using the WiFi communication.” 
     The communication throughput obtaining unit  162  obtains a communication throughput for each wireless communication protocol according to the communication s. Specifically, the communication throughput obtaining unit  162  measures the wireless quality of the wireless communication using the LTE communication and refers to an internal table in which the wireless quality and the communication throughput are associated with each other to obtain the communication throughput corresponding to the measured wireless quality. The communication throughput obtaining unit  162  measures the wireless quality of the wireless communication using the WiFi communication and refers to an internal table to obtain the communication throughput corresponding to the measured wireless quality. 
     The communication efficiency calculating unit  163  calculates the communication efficiency of the wireless communication (synchronized wireless communication) using the LTE communication and the WiFi communication at the same time, on the basis of power consumptions obtained for each of the wireless communication protocols according to each communication and the communication throughput obtained for each of the wireless communication protocols according to each communication. Specifically, the communication efficiency calculating unit  163  obtains the power consumption for the wireless communication using the LTE communication and the power consumption for the wireless communication using the WiFi communication from the power consumption obtaining unit  161 . The communication efficiency calculating unit  163  obtains the communication throughput for the wireless communication using the LTE communication and the communication throughput for the wireless communication using the WiFi communication from the communication throughput obtaining unit  162 . The communication efficiency calculating unit  163  adds the power consumption for the wireless communication using the LTE communication and the power consumption for the wireless communication using the WiFi communication to calculate the power consumption during synchronized wireless communication. The communication efficiency calculating unit  163  adds the communication throughput for the wireless communication using the LTE communication and the communication throughput for the wireless communication using the WiFi communication to calculate the communication throughput during synchronized wireless communication. The communication efficiency calculating unit  163  divides the communication throughput during synchronized wireless communication by the power consumption during synchronized wireless communication to obtain the communication efficiency during synchronized wireless communication. 
     The communication control unit  164  obtains the communication efficiency during synchronized wireless communication from the communication efficiency calculating unit  163 . The communication control unit  164  internally retains a certain threshold. The communication control unit  164  determines whether the communication efficiency during synchronized wireless communication is equal to or less than the certain threshold. The communication control unit  164  instructs the wireless control unit  130  to continue the wireless communication using the LTE communication and the WiFi communication at the same time if the communication efficiency during synchronized wireless communication exceeds the threshold. Conversely, the communication control unit  164  instructs the wireless control unit  130  to disconnect the wireless communication using the WiFi communication that was added most recently if the communication efficiency during synchronized wireless communication is equal to or less than the threshold. 
     An explanation will be provided below of a detailed example of control of wireless communication using the LTE communication and the WiFi communication at the same time. First, an explanation will be provided of an example in which the wireless communication is continued using the LTE communication and the WiFi communication at the same time. In the example, it is assumed that the communication throughput and the power consumption for the wireless communication using the LTE communication are 100 Mbps and 1 W respectively, and the communication throughput and the power consumption for the wireless communication using the WiFi communication are 30 Mbps and 0.2 W respectively. 
     In this example, the communication efficiency calculating unit  163  adds the power consumption for the wireless communication using the LTE communication and the power consumption for the wireless communication using the WiFi communication to obtain the power consumption during synchronized wireless communication as 1.2 W. The communication efficiency calculating unit  163  adds the communication throughput for the wireless communication using the LTE communication and the communication throughput for the wireless communication using the WiFi communication to obtain the communication throughput during synchronized wireless communication as 130 Mbps. The communication efficiency calculating unit  163  divides the communication throughput during synchronized wireless communication by the power consumption during synchronized wireless communication to obtain the communication efficiency during synchronized wireless communication as 108 Mbps/W. 
     The communication control unit  164  continues the wireless communication using the LTE communication and the WiFi communication at the same time since the communication efficiency during synchronized wireless communication that is 108 Mbps/W is greater than the certain threshold (e.g., 50 Mbps/W). As a result, the communication throughput related to the wireless communication is improved. 
     The following is an explanation of an example in which the wireless communication using the LTE communication and the WiFi communication where the WiFi communication is added after the LTE communication. In the example, it is assumed that the communication throughput and the power consumption for the wireless communication using the LTE communication are 30 Mbps and 0.2 W respectively, and the communication throughput and the power consumption for the wireless communication using the WiFi communication are 10 Mbps and 1 W respectively. 
     In this example, the communication efficiency calculating unit  163  adds the power consumption for the wireless communication using the LTE communication and the power consumption for the wireless communication using the WiFi communication to obtain the power consumption during synchronized wireless communication as 1.2 W. The communication efficiency calculating unit  163  calculates the communication throughput using the LTE communication as 40 Mbps. The communication efficiency calculating unit  163  divides the communication throughput during synchronized wireless communication by the power consumption during synchronized wireless communication to obtain the communication efficiency during synchronized wireless communication as 33 Mbps/W. 
     The communication control unit  164  disconnects the wireless communication using the WiFi communication that was added after the LTE communication since the communication efficiency during synchronized wireless communication that is 33 Mbps/W is less than the certain threshold that is 50 Mbps/W. As a result, an increase in the power consumption related to the wireless communication is suppressed. 
     An explanation of a process flow by a mobile station according to the first embodiment will be provided next.  FIG. 2  is a flow chart of processing by a mobile station according to the first embodiment. As illustrated in  FIG. 2 , the wireless control unit  130  of the mobile station  100  is controlled by the LTE wireless communication unit  110  to connect with a LTE base station according to a policy stored in advance (step S 101 ). The power consumption obtaining unit  161  of the main control unit  160  obtains the power consumption of the wireless communication using the LTE communication, and the communication throughput obtaining unit  162  obtains the communication throughput of the wireless communication using the LTE communication (step S 102 ). 
     The wireless control unit  130  controls the WiFi wireless communication unit  120  to connect with a WiFi base station (step S 103 ). As a result, wireless communication is started using the LTE communication and the WiFi communication at the same time. The power consumption obtaining unit  161  of the main control unit  160  obtains the power consumption of the wireless communication using the WiFi communication, and the communication throughput obtaining unit  162  obtains the communication throughput of the wireless communication using the WiFi communication (step S 104 ). 
     The communication efficiency calculating unit  163  calculates the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time, on the basis of the power consumptions and the communication throughput obtained for each of the wireless communication protocols according to each communication (step S 105 ). 
     The communication control unit  164  determines whether the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time (synchronized wireless communication) is equal to or less than the threshold (step S 106 ). If the communication efficiency during synchronized wireless communication exceeds the threshold (step S 106 : No), the communication control unit  164  instructs the wireless control unit  130  to continue the wireless communication using the LTE communication and the WiFi communication at the same time (step S 107 ). 
     Conversely, if the communication efficiency during synchronized wireless communication is equal to or less than the threshold (step S 106 : Yes), the communication control unit  164  instructs the wireless control unit  130  to disconnect the wireless communication using the WiFi communication that was added most recently (step S 108 ). 
     As described above, the mobile station  100  according to the first embodiment calculates the communication efficiency of wireless communication using a plurality of communication protocols at the same time on the basis of the power consumption and the communication throughput obtained for each of the communication protocols. The mobile station  100  continues the wireless communication using the plurality of communication protocols at the same time if the communication efficiency of the wireless communication using the plurality of communication protocols at the same time exceeds a threshold, and disconnects the wireless communication using the most recently added communication protocol of the plurality of communication protocols if the communication efficiency of the wireless communication using the plurality of communication protocols at the same time is equal to or less than the threshold. As a result, the mobile station  100  according to the first embodiment improves communication throughput while suppressing an increase in power consumption. 
     Embodiment 2 
     First, an explanation of a mobile station according to a second embodiment will be provided. The mobile station according to the second embodiment is similar to the first embodiment except that a communication efficiency calculating unit  263  and a communication control unit  264  are provided respectively in place of the communication efficiency calculating unit  163  and the communication control unit  164  in the mobile station of the first embodiment. Explanations of features and elements that are similar to those of the first embodiment will be omitted. 
       FIG. 3  illustrates a configuration of a mobile station according to the second embodiment. As illustrated in  FIG. 3 , a mobile station  200  according to the second embodiment respectively includes the communication efficiency calculating unit  263  and the communication control unit  264  in place of the communication efficiency calculating unit  163  and the communication control unit  164  in the mobile station of the first embodiment. 
     The communication efficiency calculating unit  263  calculates the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time (synchronized wireless communication), on the basis of power consumptions and the communication throughput obtained for each of the wireless communication protocols according to each communication. In addition, the communication efficiency calculating unit  263  calculates the communication efficiencies of the wireless communication when the LTE communication and the WiFi communication are used separately, on the basis of the power consumptions and the communication throughput obtained for each of the wireless communication protocols according to each communication. Specifically, the communication efficiency calculating unit  263  obtains the power consumption for the wireless communication using the LTE communication and the power consumption for the wireless communication using the WiFi communication from the power consumption obtaining unit  161 . The communication efficiency calculating unit  263  obtains the communication throughput of the wireless communication using the LTE communication and the communication throughput of the wireless communication using the WiFi communication from the communication throughput obtaining unit  162 . The communication efficiency calculating unit  263  divides the communication throughput of the wireless communication using the LTE communication by the power consumption of the wireless communication using the LTE communication to calculate the communication efficiency of the wireless communication when the LTE communication is used separately. The communication efficiency calculating unit  263  divides the communication throughput of the wireless communication using the WiFi communication by the power consumption of the wireless communication using the WiFi communication to calculate the communication efficiency of the wireless communication when the WiFi communication is used separately. 
     The communication control unit  264  obtains the communication efficiency during synchronized wireless communication from the communication efficiency calculating unit  263 . The communication control unit  264  obtains the communication efficiencies calculated separately for each communication from the communication efficiency calculating unit  263 . The communication control unit  264  retains a certain threshold internally. The communication control unit  264  determines whether the communication efficiency during synchronized wireless communication is equal to or less than the certain threshold and instructs the wireless control unit  130  to continue the wireless communication using the LTE communication and the WiFi communication at the same time if the communication efficiency during synchronized wireless communication exceeds the threshold. Conversely, the communication control unit  264  instructs the wireless control unit  130  to disconnect the wireless communication using the communication with the lowest communication efficiency calculated separately for each communication if the communication efficiency during synchronized wireless communication is equal to or less than the threshold. For example, if the communication efficiency of wireless communication using a communication B is the lowest among communication s A, B, and C, the communication control unit  264  instructs the wireless control unit  130  to disconnect the wireless communication using the communication B. 
     An explanation of processing by the mobile station according to the second embodiment will be provided.  FIG. 4  is a flow chart of processing by the mobile station according to the second embodiment. The steps S 201  to S 205  in  FIG. 4  are similar to the steps S 101  to S 105  in  FIG. 2  and explanations thereof will be omitted. 
     The communication efficiency calculating unit  263  separately calculates the communication efficiencies of the wireless communication using the LTE communication and the wireless communication using the WiFi communication, on the basis of the power consumptions and the communication throughput obtained for each of the wireless communication protocols according to each communication (step S 206 ). 
     The communication control unit  264  determines whether the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time (synchronized wireless communication) is equal to or less than the threshold (step S 207 ). If the communication efficiency during synchronized wireless communication exceeds the threshold (step S 207 : No), the communication control unit  264  instructs the wireless control unit  130  to continue the wireless communication using the LTE communication and the WiFi communication at the same time (step S 208 ). 
     Conversely, if the communication efficiency during synchronized wireless communication is equal to or less than the threshold (step S 207 : Yes), the communication control unit  264  instructs the wireless control unit  130  to disconnect the wireless communication using the communication that has the lowest communication efficiency (step S 209 ). 
     As described above, the mobile station  200  according to the second embodiment disconnects the wireless communication using the communication protocol with the lowest communication efficiency among the plurality of communication protocols if the communication efficiency of the wireless communication using the plurality of communication protocols at the same time is equal to or less than the threshold. As a result, the mobile station  200  according to the second embodiment minimizes the decrease in communication throughput and reduces power consumption when disconnecting the wireless communication using any of the communication protocols among the plurality of communication protocols. 
     Embodiment 3 
     Next, an explanation of a mobile station according to a third embodiment will be provided. The mobile station according to the third embodiment is similar to the mobile station according to the first embodiment except that a data monitoring unit  365  is further provided and a communication control unit  364  is provided in place of the communication control unit  164  in the mobile station of the first embodiment. Explanations of features and elements that are similar to those of the first embodiment will be omitted. 
       FIG. 5  illustrates a configuration of a mobile station according to the third embodiment. As illustrated in  FIG. 5 , a mobile station  300  according to the third embodiment includes the data monitoring unit  365  in addition to the units provided in the mobile station  100  according to the first embodiment. The mobile station  300  according to the third embodiment includes the communication control unit  364  in place of the communication control unit  164  in the mobile station according to the first embodiment. 
     The data monitoring unit  365  monitors whether data transmitted through the wireless communication using the LTE communication and the WiFi communication at the same time is communication throughput guaranteed data that includes a requested communication throughput that is a certain communication throughput requested for real-time transmission of the data. The communication throughput guaranteed data includes moving image data used for playing video images such as in games and the like, and voice over internet protocol (VoIP) data that is packet data used in voice communication. 
     The data monitoring unit  365  extracts the requested communication throughput from data that is detected as communication throughput guaranteed data, and outputs the requested communication throughput to the communication control unit  364 . 
     The communication control unit  364  obtains the communication efficiency during synchronized wireless communication from the communication efficiency calculating unit  163 . The communication control unit  364  obtains the requested communication throughput from the data monitoring unit  365 . The communication control unit  364  retains a certain threshold internally. The communication control unit  364  determines whether the communication efficiency during synchronized wireless communication is equal to or less than the certain threshold. The communication control unit  364  instructs the wireless control unit  130  to continue the wireless communication using the LTE communication and the WiFi communication at the same time if the communication efficiency during synchronized wireless communication exceeds the threshold. 
     Alternatively, the communication control unit  364  performs the following processing if the data transmitted during the synchronized wireless communication detected by the data monitoring unit  365  is the communication throughput guaranteed data when the communication efficiency during the synchronized wireless communication is equal to or less than the threshold. That is, the communication control unit  364  determines whether the communication throughput of the wireless communication using a communication protocol other than the communication protocol added most recently among the plurality of communication protocols satisfies the requested communication throughput. For example, the communication control unit  364  determines whether the communication throughput of the wireless communication using the LTE communication other than the WiFi communication that was added most recently satisfies the requested communication throughput. The communication control unit  364  instructs the wireless control unit  130  to continue the wireless communication using the LTE communication and the WiFi communication at the same time if the communication throughput of the wireless communication using the LTE communication does not satisfy the requested communication throughput. The communication control unit  364  instructs the wireless control unit  130  to disconnect the wireless communication using the WiFi communication that was most recently added if the communication throughput of the wireless communication using the LTE communication satisfies the requested communication throughput. 
     The communication control unit  364  performs the following processing if the data transmitted during the synchronized wireless communication detected by the data monitoring unit  365  is not communication throughput guaranteed data when the communication efficiency during the synchronized wireless communication is equal to or less than the threshold. Specifically, the communication control unit  364  instructs the wireless control unit  130  to disconnect the wireless communication using the WiFi communication that was most recently added. 
     Next, an explanation of processing by the mobile station according to the third embodiment will be provided.  FIG. 6  is a flow chart of processing by the mobile station according to the third embodiment. The steps S 301  to S 305  in  FIG. 6  are similar to the steps S 101  to S 105  in  FIG. 2  and explanations thereof will be omitted. 
     The communication control unit  364  determines whether the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time (synchronized wireless communication) is equal to or less than the threshold (step S 306 ). If the communication efficiency during synchronized wireless communication exceeds the threshold (step S 306 : No), the communication control unit  364  instructs the wireless control unit  130  to continue the wireless communication using the LTE communication and the WiFi communication at the same time (step S 307 ). 
     If the communication efficiency during synchronized wireless communication is equal to or less than the threshold (step S 306 : Yes), the communication control unit  364  determines whether a detection result that indicates whether the data transmitted during the synchronized wireless communication is communication throughput guaranteed data has been received from the data monitoring unit  365  (step S 308 ). 
     If the detection result that indicates that the data is communication throughput guaranteed data is received (step S 308 : Yes), the communication control unit  364  determines whether the wireless communication using the LTE communication satisfies the requested communication throughput (step S 309 ). If the communication control unit  364  determines that the communication throughput of the wireless communication using the LTE communication does not satisfy the requested communication throughput (step S 309 : No), the processing advances to step S 307 . 
     If the detection result that indicates that the data is communication throughput guaranteed data is not received (step S 308 : No), or the communication control unit  364  determines that the communication throughput of the wireless communication using the LTE communication satisfies the requested communication throughput (step S 309 : Yes), the following processing is performed. Specifically, the communication control unit  364  instructs the wireless control unit  130  to disconnect the wireless communication using the WiFi communication (step S 310 ). 
     As described above, the mobile station  300  according to the third embodiment monitors whether the transmitted data is communication throughput guaranteed data if the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time is equal to or less than the threshold. The mobile station  300  determines whether the communication throughput of the wireless communication using the LTE communication other than the most recently added WiFi communication satisfies the requested communication throughput if the transmitted data is detected as communication throughput guaranteed data. The mobile station  300  disconnects the communication throughput of the wireless communication using the most recently added WiFi communication if the communication throughput of the wireless communication using the LTE communication satisfies the requested communication throughput. Conversely, the mobile station  300  continues the wireless communication using the LTE communication and the WiFi communication at the same time if the communication throughput of the wireless communication using the LTE communication does not satisfy the requested communication throughput. As a result, the mobile station  300  according to the third embodiment is able to reduce an increase in power consumption while prioritizing the communication throughput guarantee of the communication throughput guaranteed data in which a certain communication throughput is requested. 
     Embodiment 4 
     Next, an explanation of a mobile station according to a fourth embodiment will be provided. The mobile station according to the fourth embodiment is similar to the mobile station according to the first embodiment except that a remaining battery capacity obtaining unit  465  and a threshold updating unit  466  are further provided and a communication control unit  464  is provided in place of the communication control unit  164  in the mobile station of the first embodiment. Explanations of features and elements that are similar to those of the first embodiment will be omitted. 
       FIG. 7  illustrates a configuration of the mobile station according to the fourth embodiment. As illustrated in  FIG. 7 , a mobile station  400  according to the fourth embodiment includes the remaining battery capacity obtaining unit  465  and the threshold updating unit  466  in addition to the units provided in the mobile station  100  according to the first embodiment. The mobile station  400  according to the fourth embodiment includes the communication control unit  464  in place of the communication control unit  164  in the mobile station  100  according to the first embodiment. 
     The remaining battery capacity obtaining unit  465  obtains a remaining battery capacity that represents the remaining capacity of a battery mounted in the mobile station  400 . The remaining battery capacity obtaining unit  465  outputs the obtained remaining battery capacity to the threshold updating unit  466 . 
     The threshold updating unit  466  receives the remaining battery capacity from the remaining battery capacity obtaining unit  465 . The threshold updating unit  466  updates a threshold retained in the communication control unit  464  so that the threshold retained in the communication control unit  464  increases correspondingly to a decrease in the remaining battery capacity. 
       FIG. 8  describes a correspondence relation of remaining battery capacity and the threshold. The horizontal axis in  FIG. 8  represents a remaining battery capacity X [%], and the vertical axis represents a threshold F(X) [bps/W] retained in the communication control unit  464 . As illustrated in  FIG. 8 , the threshold F(X) retained in the communication control unit  464  increases correspondingly to a decrease in the remaining battery capacity X. 
     The communication control unit  464  obtains the communication efficiency during synchronized wireless communication from the communication efficiency calculating unit  163 . The threshold that the communication control unit  464  retains internally is automatically updated by the threshold updating unit  466 . The communication control unit  464  determines whether the communication efficiency during synchronized wireless communication is equal to or less than the threshold updated by the threshold updating unit  466 . The communication control unit  464  instructs the wireless control unit  130  to continue the wireless communication using the LTE communication and the WiFi communication at the same time if the communication efficiency during synchronized wireless communication exceeds the threshold updated by the threshold updating unit  466 . 
     Conversely, the communication control unit  464  instructs the wireless control unit  130  to disconnect the wireless communication using the WiFi communication that was added most recently if the communication efficiency during synchronized wireless communication is equal to or less than the threshold updated by the threshold updating unit  466 . 
     Next, an explanation of processing by the mobile station according to the fourth embodiment will be provided.  FIG. 9  is a flow chart of processing by the mobile station according to the fourth embodiment. The steps S 401  to S 405  in  FIG. 9  are similar to the steps S 101  to S 105  in  FIG. 2  and explanations thereof will be omitted. 
     The threshold updating unit  466  determines whether the mobile station  400  is recharging (step S 406 ). If the mobile station  400  is recharging (step S 406 : Yes), the threshold updating unit  466  updates the threshold held in the communication control unit  464  to zero (step S 407 ) and the processing advances to step S 410 . 
     Alternatively, if the mobile station  400  is not recharging (step S 406 : No), the remaining battery capacity obtaining unit  465  obtains the remaining battery capacity and outputs the remaining battery capacity to the threshold updating unit  466  (step S 408 ). The threshold updating unit  466  updates the threshold so that the threshold held in the communication control unit  464  increases correspondingly to a decrease in the remaining battery capacity (step S 409 ). 
     The communication control unit  464  determines whether the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time (synchronized wireless communication) is equal to or less than the threshold (step S 410 ). If the communication efficiency during synchronized wireless communication exceeds the threshold (step S 410 : No), the communication control unit  464  instructs the wireless control unit  130  to continue the wireless communication using the LTE communication and the WiFi communication at the same time (step S 411 ). 
     If the communication efficiency during synchronized wireless communication is equal to or less than the threshold (step S 410 : Yes), the communication control unit  464  instructs the wireless control unit  130  to disconnect the wireless communication using the WiFi communication that was added most recently (step S 412 ). 
     As described above, the mobile station  400  according to the fourth embodiment automatically updates the threshold so that the threshold increases correspondingly to a decrease in the remaining battery capacity. The mobile station  400  disconnects the wireless communication using the most recently added communication protocol of the plurality of communication protocols if the communication efficiency of the wireless communication using the plurality of communication protocols at the same time is equal to or less than the updated threshold. As a result, the mobile station  400  according to the fourth embodiment effectively suppresses any increases in the power consumption as the remaining battery capacity falls. 
     Embodiment 5 
     Next, an explanation of a mobile station according to a fifth embodiment will be provided. The mobile station according to the fifth embodiment is similar to the first embodiment except that a main control unit  560  is provided in place of the main control unit  160  of the mobile station according to the first embodiment, and a plurality of amplifiers are mounted in the RF units  111  and  121 . Explanations of features and elements that are similar to those of the first embodiment will be omitted. 
       FIG. 10  illustrates a configuration of the mobile station according to the fifth embodiment. As illustrated in  FIG. 10 , a mobile station  500  according to the fifth embodiment includes the main control unit  560  in place of the main control unit  160  in the mobile station  100  according to the first embodiment. 
     Moreover, a plurality of amplifiers is mounted in the RF unit  111  of the LTE wireless communication unit  110  and in the RF unit  121  of the WiFi wireless communication unit  120 . In other words, the LTE wireless communication unit  110  and the WiFi wireless communication unit  120  have a plurality of switchable amp modes in which the number of amplifiers applicable to the wireless communication are different. In the present embodiment, it is assumed that the LTE wireless communication unit  110  and the WiFi wireless communication unit  120  have two amp modes: an amp mode H for two amplifiers, and an amp mode L for one amplifier. 
     The main control unit  560  includes a power consumption obtaining unit  561 , a communication throughput obtaining unit  562 , a communication efficiency calculating unit  563 , a communication control unit  564 , and an amp mode setting unit  565 . 
     The power consumption obtaining unit  561  obtains power consumptions for each combination of the amp modes and the wireless communication protocols according to the communication systems. Specifically, the power consumption obtaining unit  561  obtains the power consumption of the wireless communication using the LTE communication in each amp mode. The power consumption obtaining unit  561  obtains the power consumption of the wireless communication using the WiFi communication in each amp mode. 
     The communication throughput obtaining unit  562  obtains communication throughput for each combination of the amp modes and the wireless communication protocols according to the communication s. Specifically, the communication throughput obtaining unit  562  obtains the communication throughput of the wireless communication using the LTE communication in each amp mode. The communication throughput obtaining unit  562  obtains the communication throughput of the wireless communication using the WiFi communication in each amp mode. 
     The communication efficiency calculating unit  563  calculates the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time (synchronized wireless communication), on the basis of the power consumptions and the communication throughput obtained for each of the combinations of the amp modes and the wireless communication protocols according to each communication. Specifically, the communication efficiency calculating unit  563  obtains the power consumption for the wireless communication using the LTE communication and the power consumption for the wireless communication using the WiFi communication for each amp mode from the power consumption obtaining unit  561 . The communication efficiency calculating unit  563  obtains the communication throughput of the wireless communication using the LTE communication and the communication throughput of the wireless communication using the WiFi communication for each amp mode from the communication throughput obtaining unit  562 . The communication efficiency calculating unit  563  adds the power consumption for the wireless communication using the LTE communication and the power consumption for the wireless communication using the WiFi communication to calculate the power consumption during synchronized wireless communication in each amp mode. The communication efficiency calculating unit  563  adds the communication throughput for the wireless communication using the LTE communication and the communication throughput for the wireless communication using the WiFi communication to calculate the communication throughput during synchronized wireless communication in each amp mode. The communication efficiency calculating unit  563  divides the communication throughput during synchronized wireless communication by the power consumption during synchronized wireless communication to obtain the communication efficiency during synchronized wireless communication in each amp mode. 
     The communication control unit  564  correspondingly prioritizes the communication efficiency corresponding to the amp mode with the highest communication throughput among the communication efficiencies calculated by the communication efficiency calculating unit  563 , and compares the prioritized communication efficiency with a threshold. The communication control unit  564  instructs the wireless control unit  130  to disconnect the wireless communication using the most recently added WiFi communication if the communication efficiency corresponding to the amp mode with the lowest communication throughput is equal to or below the threshold. 
     The communication control unit  564  controls the amp mode setting unit  565  to switch between the amp modes in the LTE wireless communication unit  110  and the WiFi wireless communication unit  120 . 
     The amp mode setting unit  565  is controlled by the communication control unit  564  to switch the amp mode settings of the LTE wireless communication unit  110  and the WiFi wireless communication unit  120  between the amp mode H and the amp mode L. 
     Next, an explanation of the mobile station according to the fifth embodiment will be provided.  FIG. 11  is a flow chart of processing by the mobile station according to the fifth embodiment. As illustrated in  FIG. 11 , first the wireless control unit  130  of the mobile station  500  is controlled by the LTE wireless communication unit  110  to connect with a LTE base station according to a policy stored in advance (step S 501 ). The power consumption obtaining unit  561  of the main control unit  560  obtains the power consumption of the wireless communication using the LTE communication, and the communication throughput obtaining unit  562  obtains the communication throughput of the wireless communication using the LTE communication (step S 502 ). The power consumption obtaining unit  561  and the communication throughput obtaining unit  562  set the respective amp modes to default amp modes and respectively obtain the power consumptions and the communication throughput. 
     The wireless control unit  130  controls the WiFi wireless communication unit  120  to connect with a WiFi base station (step S 503 ). As a result, wireless communication is started using the LTE communication and the WiFi communication at the same time. The power consumption obtaining unit  561  of the main control unit  560  obtains the power consumption of the wireless communication using the WiFi communication for each amp mode, and the communication throughput obtaining unit  562  obtains the communication throughput of the wireless communication using the WiFi communication for each amp mode (step S 504 ). 
     The communication control unit  564  controls the amp mode setting unit  565  to set the amp mode H with a relatively high communication throughput (step S 505 ). The communication efficiency calculating unit  563  calculates the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time, on the basis of the power consumptions and the communication throughput obtained as a combination of the wireless communication protocols according to each communication and the amp mode H (step S 506 ). 
     The communication control unit  564  determines whether the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time (synchronized wireless communication) is equal to or less than the threshold (step S 507 ). If the communication efficiency during synchronized wireless communication exceeds the threshold (step S 507 : No), the processing advances to step S 511 . 
     Conversely, if the communication efficiency during synchronized wireless communication is equal to or less than the threshold (step S 507 : Yes), the communication control unit  564  controls the amp mode setting unit  565  to set the amp mode L with a relatively low communication throughput (step S 508 ). The communication efficiency calculating unit  563  calculates the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time, on the basis of the power consumptions and the communication throughput obtained as a combination of the wireless communication protocols according to each communication and the amp mode L (step S 509 ). 
     The communication control unit  564  determines whether the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time (synchronized wireless communication) is equal to or less than the threshold (step S 510 ). If the communication efficiency during synchronized wireless communication exceeds the threshold (step S 510 : No), the communication control unit  564  instructs the wireless control unit  130  to continue the wireless communication using the LTE communication and the WiFi communication at the same time (step S 511 ). 
     Conversely, if the communication efficiency during synchronized wireless communication is equal to or less than the threshold (step S 510 : Yes), the communication control unit  564  instructs the wireless control unit  130  to disconnect the wireless communication using the WiFi communication that was added most recently (step S 512 ). 
     As described above, the mobile station  500  according to the fifth embodiment prioritizes the communication efficiency corresponding to the amp mode with the highest communication throughput and compares the prioritized communication efficiency with the threshold. The mobile station  500  disconnects the wireless communication using the most recently added communication protocol among the plurality of communication protocols if the communication efficiency corresponding to the amp mode with the lowest communication throughput is equal to or less than the threshold. As a result, the mobile station  500  according to the fifth embodiment is able to set an optimal amp mode while improving communication throughput and suppressing power consumption. 
     Embodiment 6 
     Next, an explanation of a mobile station according to a sixth embodiment will be provided. The mobile station according to the sixth embodiment is similar to the mobile station according to the first embodiment except that a communication control unit  664  is provided in place of the communication control unit  564  in the mobile station of the fifth embodiment. Explanations of features and elements that are similar to those of the first embodiment will be omitted. 
       FIG. 12  illustrates a configuration of the mobile station according to the sixth embodiment. As illustrated in  FIG. 12 , a mobile station  600  according to the sixth embodiment is similar to the mobile station  500  according to the fifth embodiment except that the communication control unit  664  is provided in place of the communication control unit  564  in the mobile station of the fifth embodiment. 
     The communication control unit  664  selects an amp mode corresponding to the highest communication efficiency among the communication efficiencies calculated by the communication efficiency calculating unit  563 , and compares the highest communication efficiency with the threshold. The communication control unit  664  instructs the wireless control unit  130  to disconnect the wireless communication using the most recently added WiFi communication if the communication efficiency corresponding to the amp mode with the highest communication efficiency is equal to or below the threshold. 
     Next, an explanation of processing by the mobile station according to the sixth embodiment will be provided.  FIG. 13  is a flow chart of the processing by the mobile station according to the sixth embodiment. As illustrated in  FIG. 13 , first the wireless control unit  130  of the mobile station  600  is controlled by the LTE wireless communication unit  110  to connect with a LTE base station according to a policy stored in advance (step S 601 ). The power consumption obtaining unit  561  of the main control unit  660  obtains the power consumption of the wireless communication using the LTE communication for each amp mode, and the communication throughput obtaining unit  562  obtains the communication throughput of the wireless communication using the LTE communication for each amp mode (step S 602 ). 
     The wireless control unit  130  controls the WiFi wireless communication unit  120  to connect with a WiFi base station (step S 603 ). As a result, wireless communication is started using the LTE communication and the WiFi communication at the same time. The power consumption obtaining unit  561  of the main control unit  660  obtains the power consumption of the wireless communication using the WiFi communication for each amp mode, and the communication throughput obtaining unit  562  obtains the communication throughput of the wireless communication using the WiFi communication for each amp mode (step S 604 ). 
     The communication efficiency calculating unit  563  calculates the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time, on the basis of the power consumptions and the communication throughput obtained as a combination of the amp modes and the wireless communication protocols according to each communication (step S 605 ). 
     The communication control unit  664  selects an amp mode corresponding to the highest communication efficiency among the communication efficiencies calculated by the communication efficiency calculating unit  563 , and controls the amp mode setting unit  565  to set the amp mode with the highest communication efficiency (step S 606 ). 
     The communication control unit  664  determines whether the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time (synchronized wireless communication) is equal to or less than the threshold (step S 607 ). If the communication efficiency during synchronized wireless communication exceeds the threshold (step S 607 : No), the communication control unit  664  instructs the wireless control unit  130  to continue the wireless communication using the LTE communication and the WiFi communication at the same time (step S 608 ). 
     Conversely, if the communication efficiency during synchronized wireless communication is equal to or less than the threshold (step S 607 : Yes), the communication control unit  664  instructs the wireless control unit  130  to disconnect the wireless communication using the WiFi communication that was added most recently (step S 609 ). 
     As described above, the mobile station  600  according to the sixth embodiment selects an amp mode corresponding to the highest communication efficiency and compares the highest communication efficiency with the threshold. The mobile station  600  disconnects the wireless communication using the most recently added communication protocol among the plurality of communication protocols if the highest communication efficiency is equal to or less than the threshold. As a result, the mobile station  600  according to the sixth embodiment is able to set an optimal amp mode while improving communication throughput and suppressing power consumption. 
     Embodiment 7 
     Next, an explanation of a mobile station according to a seventh embodiment will be provided. The mobile station according to the seventh embodiment is similar to the first embodiment except that a communication efficiency calculating unit  763  and a communication control unit  764  are provided respectively in place of the communication efficiency calculating unit  163  and the communication control unit  164  in the mobile station of the first embodiment. Explanations of features and elements that are similar to those of the first embodiment will be omitted. 
       FIG. 14  illustrates a configuration of the mobile station according to the seventh embodiment. As illustrated in  FIG. 14 , a mobile station  700  according to the seventh embodiment respectively includes the communication efficiency calculating unit  763  and the communication control unit  764  in place of the communication efficiency calculating unit  163  and the communication control unit  164  in the mobile station  100  of the first embodiment. 
     The communication efficiency calculating unit  763  calculates the communication efficiencies of wireless communication when the LTE communication and the WiFi communication are used separately, on the basis of the power consumptions and the communication throughput obtained for each of the wireless communication protocols according to each communication. Specifically, the communication efficiency calculating unit  763  obtains the power consumption for the wireless communication using the LTE communication and the power consumption for the wireless communication using the WiFi communication from the power consumption obtaining unit  161 . The communication efficiency calculating unit  763  obtains the communication throughput of the wireless communication using the LTE communication and the communication throughput of the wireless communication using the WiFi communication from the communication throughput obtaining unit  162 . The communication efficiency calculating unit  763  divides the communication throughput of the wireless communication using the LTE communication by the power consumption of the wireless communication using the LTE communication to calculate the communication efficiency of the wireless communication when the LTE communication is used separately. The communication efficiency calculating unit  763  divides the communication throughput for the wireless communication using the LTE communication and the WiFi communication at the same time by the power consumptions for the wireless communication using the LTE communication and the WiFi communication at the same time, to obtain the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time. 
     The communication control unit  764  obtains the communication efficiency calculated separately for each of the communication s from the communication efficiency calculating unit  763 . The communication control unit  764  determines whether the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time is greater than the communication efficiency of the wireless communication using the LTE communication. If the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time is greater than the communication efficiency of the wireless communication using the LTE communication, the communication control unit  764  instructs the wireless control unit  130  to continue the wireless communication using the LTE communication and the WiFi communication at the same time. If the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time is equal to or less than the communication efficiency of the wireless communication using the LTE communication, the communication control unit  764  instructs the wireless control unit  130  to disconnect the wireless communication using the WiFi communication that was added most recently. 
     Next, an explanation of processing by a mobile station according to the seventh embodiment will be provided.  FIG. 15  is a flow chart of the processing by the mobile station according to the seventh embodiment. The steps S 701  to S 704  in  FIG. 15  are similar to the steps S 101  to S 104  in  FIG. 2  and explanations thereof will be omitted. 
     The communication efficiency calculating unit  763  separately calculates the communication efficiencies of the wireless communication using the LTE communication and of the wireless communication using the LTE communication and the WiFi communication at the same time, on the basis of the power consumptions and the communication throughput obtained for each of the wireless communication protocols according to each communication (step S 705 ). 
     The communication control unit  764  determines whether the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time is greater than the communication efficiency of the wireless communication using the LTE communication (step S 706 ). If the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time is greater than the communication efficiency of the wireless communication using the LTE communication (step S 706 : Yes), the communication control unit  764  performs the processing described below. Specifically, the communication control unit  764  instructs the wireless control unit  130  to continue the wireless communication using the LTE communication and the WiFi communication at the same time (step S 707 ). 
     Conversely, if the communication efficiency of the wireless communication using the LTE communication and the WiFi communication at the same time is equal to or less than the communication efficiency of the wireless communication using the LTE communication (step S 706 : No), the communication control unit  764  performs the processing described below. Specifically, the communication control unit  764  instructs the wireless control unit  130  to disconnect the wireless communication using the WiFi communication that was added most recently (step S 708 ). 
     As described above, the mobile station  700  according to the seventh embodiment disconnects the wireless communication using the most recently added communication protocol if the communication efficiency of the wireless communication using the most recently added communication protocol is equal to or less than the communication efficiency of the wireless communication using the communication protocol that was previously connected. As a result, the mobile station  700  according to the seventh embodiment is able to disconnect wireless communication having poor communication efficiency without performing a threshold determination, and is able to reduce the memory for retaining the threshold and reduce power consumption. 
     An example of a hardware configuration of each of the mobile stations in this application described as follows. The mobile station in this application includes a wireless interface, a processor, a memory, a digital circuit, and an analog circuit, for example. A wireless interface is an interface device that is used to perform wireless communication with a base station. For example, a wireless interface is constructed by an antenna and analog circuits. A processor is a device that processes data. Examples of the processor are a central processing unit (CPU) and a digital signal processor (DSP). A memory is a device that stores data. Examples of the memory are a read only memory (ROM) and a random access memory (RAM). A digital circuit is an electronic circuit that performs a digital operation. Examples of the logical circuit are a large scale integration (LSI), a field-programming gate array (FPGA) and an application specific integrated circuit (ASIC). An analog circuit is an electronic circuit that performs an analog operation. 
     Correspondence relationships between the mobile station  100  illustrated in  FIG. 1 , the mobile station  200  illustrated in  FIG. 3 , the mobile station  300  illustrated in  FIG. 5 , the mobile station  400  illustrated in  FIG. 7 , the mobile station  500  illustrated in  FIG. 10 , the mobile station  600  illustrated in  FIG. 12 , or the mobile station  700  illustrated in  FIG. 14  and the hardware configuration are described as follows. For example, the antennas  111   a  and  111   b  correspond to the wireless network interface. For example, the LTE wireless communication unit  110  and the WiFi wireless communication unit  120  correspond to the analog circuit, the digital circuit, the processor, and the memory. For example, the wireless communication unit  130 , IP packet processing unit  140 , application processing unit  150 , and the main control unit  160 ,  260 ,  360 ,  460 ,  560 ,  660 , or  760  correspond to the processor, the memory and the digital circuit. 
     All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.