JP2009170981A - Mobile communication terminal, and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile communication terminal capable of extending operable time when battery residual capacity is small while preventing deterioration in receiving quality. <P>SOLUTION: The mobile communication terminal is provided with a moving speed information acquisition part 141 for acquiring speed information indicating the moving speed of the mobile communication terminal, a battery residual capacity detection part 142 for detecting battery residual capacity, a parameter selection part 144 for selecting at least one communication parameter which may exert influence on receiving quality and power consumption on the basis of the speed information and the battery residual capacity, and a parameter setting part 145 for setting the selected communication parameter in a transmitting/receiving part. The parameter selection part 144, when the battery residual capacity is smaller than prescribed capacity, selects a communication parameter so as to reduce power consumption. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a mobile communication terminal that operates using electric power stored in a battery, and a control method thereof.

  Generally, a mobile communication terminal includes a transmission / reception unit that transmits and receives radio signals to and from a radio base station, and a battery that stores at least power supplied to the transmission / reception unit.

  Such a mobile communication terminal searches for a radio base station with the highest reception quality of a radio signal (for example, a pilot signal) from a plurality of radio base stations (hereinafter, “base station search”), The highest radio base station is selected as a connection destination radio base station.

  Therefore, in the mobile communication terminal, it is possible to improve the reception quality as the frequency of executing the base station search increases. However, the power consumption in the transmission / reception unit increases as the frequency of executing the base station search increases.

In addition, when the moving speed of the mobile communication terminal is high, the reception quality tends to deteriorate. For this reason, a mobile communication terminal that increases the frequency of executing a base station search when the mobile communication terminal moves at high speed has been proposed (see Patent Document 1). According to the mobile communication terminal described in Patent Document 1, it is possible to prevent a decrease in reception quality even during high-speed movement.
JP 2004-104265 A

  By the way, the opportunity for the user to charge the battery is limited, and when the remaining battery level is low, it is desired to extend the operable time by reducing the power consumption of the mobile communication terminal.

  However, in the mobile communication terminal described in Patent Document 1, even when the remaining battery level is low, the base station search frequency increases as the movement speed of the mobile communication terminal increases, so that the power consumption increases and the operable time is shortened. There was a problem.

  Therefore, the present invention has been made to solve the above-described problem, and a mobile communication terminal capable of extending the operable time when the remaining battery capacity is low while preventing a decrease in reception quality and An object is to provide a control method thereof.

  A first feature of the present invention is a mobile communication terminal (transmission / reception unit 120) that transmits / receives a radio signal to / from a radio base station, and a battery (battery 130) that stores at least power supplied to the transmission / reception unit. Mobile communication terminal 100), a speed information acquisition unit (movement speed information acquisition unit 141) for acquiring speed information indicating the movement speed of the mobile communication terminal, and a remaining amount of electric power stored in the battery A battery remaining amount detecting unit (battery remaining amount detecting unit 142) for detecting a battery remaining amount; the speed information acquired by the speed information acquiring unit; and the battery remaining amount detected by the battery remaining amount detecting unit; Based on the parameter selection unit (parameter) for selecting at least one communication parameter that affects the reception quality of the radio signal and the power consumption of the transmission / reception unit. Data selection unit 144) and a parameter setting unit (parameter setting unit 145) for setting the communication parameter selected by the parameter selection unit in the transmission / reception unit. The gist is to select the communication parameter so as to reduce the power consumption when the amount is lower than a predetermined amount.

  According to such a mobile communication terminal, the parameter selection unit selects the communication parameter so as to reduce the power consumption when the remaining battery level is below a predetermined amount. Accordingly, there is provided a mobile communication terminal capable of extending the operable time when the remaining battery level is low while preventing the reception quality from deteriorating.

  A second feature of the present invention relates to the first feature of the present invention, wherein the parameter selection unit selects the communication parameter so as to increase the reception quality when the remaining battery capacity exceeds a predetermined amount. Is the gist.

  According to such a mobile communication terminal, when the remaining battery level is high, the communication parameter is selected so as to increase the reception quality, so that the reception quality is prevented from deteriorating.

  A third feature of the present invention relates to the second feature of the present invention, wherein the transmission / reception unit measures the reception quality of the radio signal received from the radio base station (reception quality measurement unit 143). The parameter selection unit selects the communication parameter based on the reception quality measured by the reception quality measurement unit in addition to the speed information and the remaining battery level. .

  According to such a mobile communication terminal, it is possible to select communication parameters in consideration of not only speed information and remaining battery capacity but also reception quality.

  A fourth feature of the present invention is according to the third feature of the present invention, wherein the parameter selector is located outside the radio wave reach from the radio base station based on the reception quality. A case where an out-of-service state is detected, a stop state in which the mobile communication terminal is not moving is detected based on the speed information, the out-of-service state is detected, and the stop state is detected The gist is to select the communication parameter so as to reduce the power consumption even when the remaining battery amount exceeds the predetermined amount.

  According to such a mobile communication terminal, when the out-of-service state is detected and the stop state is detected, the parameter selection unit reduces the power consumption even if the remaining battery amount exceeds a predetermined amount. Select communication parameters. As a result, power consumption is prevented from being wasted, and the operable time can be further extended.

  A fifth feature of the present invention relates to the first feature of the present invention, wherein a notification unit (display unit 150) for notifying a user of the communication parameter selected by the parameter selection unit, and a selection by the parameter selection unit An operation receiving unit (input unit 160) that receives a user operation for changing the communication parameter, and the parameter setting unit is configured to perform the user operation according to the user operation when the operation receiving unit receives the user operation. The gist is to set communication parameters.

  According to such a mobile communication terminal, communication parameters can be set according to user operations, and user convenience can be improved.

  A sixth feature of the present invention relates to any one of the first to fifth features of the present invention, wherein the transmission / reception unit searches for a radio base station having the highest reception quality from among the plurality of radio base stations. When the communication parameter is selected to increase the reception quality, the transmission / reception unit increases the frequency of executing the base station search and decreases the power consumption. The gist is to reduce the frequency of performing the base station search when the communication parameter is selected.

  According to such a mobile communication terminal, it is possible to extend the operable time when the remaining battery level is low while preventing the reception quality from deteriorating.

  A seventh feature of the present invention is a control method for controlling a mobile communication terminal having a transmission / reception unit that transmits / receives a radio signal to / from a radio base station, and a battery that stores at least power supplied to the transmission / reception unit, A step of acquiring speed information indicating a moving speed of the mobile communication terminal; a step of detecting a battery remaining amount that is a remaining amount of power stored in the battery; and the speed information acquired by the acquiring step; Selecting at least one communication parameter that affects the reception quality of the radio signal and the power consumption of the transmitting / receiving unit based on the remaining battery level detected by the detecting step; and the selecting step Setting the communication parameter selected by the transmission / reception unit, and in the selecting step If the battery level drops below a predetermined amount, and the gist of the fact that communication parameters are selected to lower the power consumption.

  According to the features of the present invention, it is possible to provide a mobile communication terminal capable of extending the operable time and the control method thereof when the remaining battery capacity is low while preventing the reception quality from deteriorating.

  Next, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings in the following embodiments, the same or similar parts are denoted by the same or similar reference numerals.

(1) Overall Schematic Configuration of Mobile Communication System FIG. 1 is an overall schematic configuration diagram of a mobile communication system 10 according to the present embodiment. As shown in FIG. 1, the mobile communication system 10 includes a mobile communication terminal 100 and radio base stations 200A and 200B.

  The mobile communication terminal 100 moves as the user of the mobile communication terminal 100 moves. When the mobile communication terminal 100 is located in a vehicle such as a train or a car, the moving speed of the mobile communication terminal 100 is, for example, about 0 km / h to 200 km / h.

  In the present embodiment, the moving speed of the mobile communication terminal 100 is referred to as a stopped state when the moving speed is about 0 km / h, a low speed (moving) from about 1 km / h to 50 km / h and a high speed (moving) from about 51 km / h to 200 km / h. .

  The mobile communication terminal 100 performs a base station search and selects a radio base station with the highest reception quality as a connection-destination radio base station. In the example of FIG. 1, the mobile communication terminal 100 is connected to and communicates with the radio base station 200A.

  The mobile communication terminal 100 performs a search based on the frequency list stored in advance in the mobile communication terminal 100 in the base station search with the power ON. If the frequency in the list can be supplemented, the mobile communication terminal 100 calculates a neighboring cell frequency from the broadcast information of the supplemented frequency and performs a base station search. When the frequency cannot be supplemented, that is, outside the service area, all frequencies in the list are searched (hereinafter referred to as “full wave search” as appropriate). The full-wave search is required for a longer time as the number of frequencies (wireless channels) to be searched increases.

  The operation of switching the connection destination by executing a base station search while mobile communication terminal 100 is waiting for an incoming call is called “cell reselection”. The operation in which the mobile communication terminal 100 performs a base station search during communication and switches connection destinations is called “handover”.

  The radio base station 200A forms a cell C1 that is a radio wave reachable range of the radio base station 200A. Similarly, the radio base station 200B forms a cell C2.

  The mobile communication terminal 100 executes standby and communication according to communication parameters specified from the radio base station 200A and communication parameters set in advance in the mobile communication terminal 100.

(2) Configuration of Mobile Communication Terminal Next, the configuration of the mobile communication terminal 100 will be described using FIG. 2 and FIG.

(2.1) Schematic hardware configuration of mobile communication terminal First, a schematic hardware configuration of the mobile communication terminal 100 will be described. FIG. 2 is a block diagram showing a schematic hardware configuration of the mobile communication terminal 100.

  As shown in FIG. 2, the mobile communication terminal 100 includes an antenna 110, a transmission / reception unit 120, a battery 130, a control unit 140, a display unit 150, an input unit 160, a microphone 170, and a speaker 180.

  The transmission / reception unit 120 receives a radio signal from the radio base station 200 </ b> A via the antenna 110. In addition, the transmission / reception unit 120 transmits a radio signal to the radio base station 200 </ b> A via the antenna 110.

  Specifically, the transmission / reception unit 120 includes a transmission unit and a reception unit that are not shown. The transmission unit includes an up-converter that increases the frequency of the radio signal, and a power amplifier that is used to amplify the radio signal. The receiving unit includes a low noise amplifier used for amplifying the radio signal and a down converter for reducing the frequency of the radio signal.

  Thus, the transmission / reception unit 120 is mainly configured by an analog circuit, and is a block that occupies most of the power consumption of the mobile communication terminal 100. That is, the power consumption of the mobile communication terminal 100 increases as the frequency at which the transmission / reception unit 120 operates increases.

  The battery 130 stores at least power supplied to the transmission / reception unit 120. In the present embodiment, the battery 130 supplies power to the entire mobile communication terminal 100. The battery 130 is not limited to a rechargeable battery (secondary battery) but may be a non-chargeable battery (primary battery).

  The display unit 150 includes a display that displays various types of information. The input unit 160 includes various buttons that accept user operations. The microphone 170 converts the user's voice into an electrical signal. The speaker 180 converts an electrical signal into sound and outputs it.

  The control unit 140 includes a CPU and a memory. The control unit 140 controls the transmission / reception unit 120, the battery 130, the display unit 150, the input unit 160, the microphone 170, and the speaker 180.

(2.1) Functional Block Configuration of Mobile Communication Terminal Next, the functional block configuration of the mobile communication terminal 100, specifically, the control unit 140 will be described. FIG. 3 is a block diagram illustrating a functional block configuration of the control unit 140.

  As shown in FIG. 3, the control unit 140 includes a movement speed information acquisition unit 141, a battery remaining amount detection unit 142, a reception quality measurement unit 143, a parameter selection unit 144, and a parameter setting unit 145.

  The movement speed information acquisition unit 141 acquires speed information indicating the movement speed of the mobile communication terminal 100. As a speed information acquisition method, for example, any of the following methods (a) to (c) can be used.

  (A) A method of calculating the Doppler frequency fd from the Rayleigh fading fluctuation (fading pitch) and obtaining the moving speed by the Doppler frequency fd. In this case, the Doppler frequency fd may be used as speed information.

  (B) A method of counting the number of cell transitions per unit time and obtaining the moving speed by the count value. In this case, not only when the mobile communication terminal 100 measures the moving speed, the mobile base station may measure the moving speed and notify the mobile communication terminal 100 of the speed information.

  (C) A well-known method for measuring the moving speed with a GPS or an acceleration sensor.

  The remaining battery level detection unit 142 detects the remaining battery level that is the remaining power level stored in the battery 130.

  The reception quality measurement unit 143 measures the reception quality of the radio signal received by the transmission / reception unit 120 from the radio base station. As the reception quality measured by the reception quality measurement unit 143, for example, a signal-to-noise ratio (SNR), a received electric field strength (RSSI), or a block error rate (BLER) can be used.

  The parameter selection unit 144 affects the reception quality and the power consumption of the transmission / reception unit 120 based on the speed information acquired by the movement speed information acquisition unit 141 and the remaining battery level detected by the remaining battery level detection unit 142. Select at least one communication parameter to provide. A specific example of the communication parameter will be described later.

  In the present embodiment, the parameter selection unit 144 selects a communication parameter based on the reception quality measured by the reception quality measurement unit 143 in addition to the speed information and the remaining battery level.

  The parameter setting unit 145 sets the communication parameter selected by the parameter selection unit 144 in the transmission / reception unit 120.

(3) Specific examples of communication parameters Next, specific examples of communication parameters will be described. FIG. 4 is a diagram for explaining a specific example of communication parameters.

  As illustrated in FIG. 4, the communication parameters include a DRX cycle, an unknown base station search interval, S-intra, Hysteresis, Time To Trigger, Reporting Range, and a full wave search interval.

  The DRX cycle is a communication parameter that defines a cycle in which the mobile communication terminal 100 searches for a known radio base station during communication. The DRX cycle is notified from the radio base station to the mobile communication terminal 100 and is initially set in the mobile communication terminal 100.

  The unknown base station search interval is a communication parameter that defines an interval at which the mobile communication terminal 100 searches for an unknown radio base station during communication. The unknown base station search interval is preset in the mobile communication terminal 100.

  S-intra is a communication parameter serving as a trigger for searching for an unknown radio base station while the mobile communication terminal 100 is communicating. Specifically, when the reception quality falls below S-intra, the mobile communication terminal 100 searches for an unknown radio base station. S-intra is notified from the radio base station to the mobile communication terminal 100 and is initially set in the mobile communication terminal 100.

  Hysteresis, Time To Trigger, and Reporting Range are communication parameters that serve as a trigger for shifting to a better cell from the result of searching for a radio base station while the mobile communication terminal 100 is waiting. The newly selected radio base station is selected as a radio base station that is the standby destination of mobile communication terminal 100. Hysteresis, Time To Trigger, and Reporting Range are notified from the radio base station to the mobile communication terminal 100 and are initially set in the mobile communication terminal 100.

  The full wave search interval is a communication parameter that defines a full wave search interval for searching for a receivable radio wave (frequency) when the mobile communication terminal 100 is in an out-of-service state. The full wave search interval is notified from the radio base station to the mobile communication terminal 100 and is initially set in the mobile communication terminal 100.

  The values of these communication parameters are selected (updated) by the parameter selection unit 144. The value of the communication parameter selected by the parameter selection unit 144 is set in the transmission / reception unit 120 by the parameter setting unit 145.

  In the present embodiment, communication parameter values differ depending on whether priority is given to improving reception quality or reduction of power consumption.

  For example, the DRX cycle is set to a small value (short cycle) when priority is given to improving reception quality. This contributes to improved reception quality but increases power consumption. On the other hand, when priority is given to reducing power consumption, the DRX cycle is set to a large value (long cycle). This reduces power consumption but leads to degradation of reception quality.

(4) Operation of Mobile Communication Terminal Next, the operation of the mobile communication terminal 100 will be described using FIG. 5 and FIG.

(4.1) General Operation of Mobile Communication Terminal First, the general operation of the mobile communication terminal 100, specifically, the operation of the parameter selection unit 144 will be described. FIG. 5 is a diagram for explaining a schematic operation of the parameter selection unit 144.

  As shown in FIG. 5, the parameter selection unit 144 selects a communication parameter according to the moving speed of the mobile communication terminal 100. Specifically, when the moving speed of mobile communication terminal 100 is high, parameter selection unit 144 updates the value of the communication parameter as the moving speed changes. On the other hand, when the moving speed of the mobile communication terminal 100 is low or stopped, the parameter selection unit 144 maintains the value of the communication parameter at a fixed value.

  Further, the parameter selection unit 144 selects a communication parameter by giving priority to reducing power consumption when the remaining battery level is below a predetermined amount, that is, when the remaining battery level is low. Here, the predetermined amount can be about 1/3 of the maximum amount of remaining battery power. On the other hand, when the remaining battery amount exceeds a predetermined amount, the communication parameter is selected giving priority to the improvement of the reception quality.

  Furthermore, the parameter selection unit 144 detects an out-of-service state, which is a state in which the mobile communication terminal 100 is located outside the radio wave reachable range (ie, cell) from the radio base station, based on the reception quality. For example, the out-of-service state can be detected by comparing a value indicating reception quality with a threshold value. The parameter selection unit 144 detects the stop state of the mobile communication terminal 100 based on the speed information. Then, when the out-of-service state is detected and the stop state is detected, the parameter selection unit 144 selects the communication parameter by giving priority to reducing power consumption even if the remaining battery amount exceeds the predetermined amount. To do.

(4.2) Detailed Operation Example of Mobile Communication Terminal Next, a detailed operation example of the mobile communication terminal 100 will be described. FIG. 6 is a flowchart showing a detailed operation example of the mobile communication terminal 100.

  In step S <b> 101, the parameter setting unit 145 sets an initial value (initial setting value) of the communication parameter in the transmission / reception unit 120.

  In step S102, the reception quality measuring unit 143 measures the reception quality.

  In step S103, the parameter selection unit 144 determines whether or not an out-of-service state has been detected based on the reception quality measured by the reception quality measurement unit 143. If an out-of-service state is detected, the process proceeds to step S104. On the other hand, when the out-of-service state is not detected, the process proceeds to step S106.

  In step S104, the moving speed information acquisition unit 141 acquires speed information.

  In step S <b> 105, the parameter selection unit 144 determines whether a stop state has been detected based on the speed information acquired by the movement speed information acquisition unit 141. If a stop state is detected, the process proceeds to step S108. On the other hand, when the stop state is not detected, the process returns to step S101.

  In step S106, the remaining battery level detection unit 142 detects the remaining battery level.

  In step S107, the parameter selection unit 144 determines whether or not the remaining battery level is low based on the remaining battery level detected by the remaining battery level detection unit 142. If it is determined that the remaining battery level is low, the process proceeds to step S108. On the other hand, if it is determined that the remaining battery level is not low, that is, it is high, the process proceeds to step S109.

  In step S108, the parameter selection unit 144 selects a communication parameter by giving priority to reducing power consumption. The selected communication parameter is set in the transmission / reception unit 120 by the parameter setting unit 145.

  In step S109, the moving speed information acquisition unit 141 acquires speed information.

  In step S110, the parameter selection unit 144 determines whether or not the moving speed of the mobile communication terminal 100 is high based on the speed information acquired by the moving speed information acquisition unit 141. If it is determined that the moving speed of the mobile communication terminal 100 is high, the process proceeds to step S111. On the other hand, when it is determined that the moving speed of the mobile communication terminal 100 is not high speed (that is, low speed), the process proceeds to step S112.

  In step S111, the parameter selection unit 144 selects a communication parameter by giving priority to improving reception quality. Specifically, the value of the communication parameter corresponding to the moving speed of the mobile communication terminal 100 is selected. That is, in step S111, the value of the communication parameter is a variable value corresponding to the moving speed. The selected communication parameter is set in the transmission / reception unit 120 by the parameter setting unit 145.

  In step S112, the parameter selection unit 144 selects communication parameters giving priority to the improvement of reception quality. Specifically, a predetermined value is selected as the communication parameter value. That is, in step S112, the value of the communication parameter is a fixed value. Here, an initial set value may be used as the predetermined value. The initial setting value includes a value tuned on the network side. For this reason, when moving at a low speed, it is possible to keep the reception quality as good as possible by selecting the communication parameter according to the initial setting value. The selected communication parameter is set in the transmission / reception unit 120 by the parameter setting unit 145.

(5) Action / Effect The parameter selection unit 144 selects a communication parameter so as to reduce power consumption when the remaining battery level is low. In the present embodiment, the parameter selection unit 144 selects a communication parameter so as to reduce the frequency of base station search when the remaining battery level is low.

  Further, the parameter selection unit 144 selects a communication parameter so as to improve the reception quality when the remaining battery level is high. In the present embodiment, the parameter selection unit 144 selects a communication parameter so as to increase the execution frequency of the base station search when the remaining battery level is high.

  Therefore, when the remaining battery capacity is low, the operable time of the mobile communication terminal 100 can be extended. In addition, when the battery remaining amount is high, it is possible to prevent the reception quality from deteriorating.

  In the present embodiment, the parameter selection unit 144 sets the base station search execution frequency as the moving speed of the mobile communication terminal 100 increases when the remaining battery level is high and the moving speed of the mobile communication terminal 100 is high. increase. Therefore, even if the moving speed of the mobile communication terminal 100 is high, it is possible to prevent the reception quality from deteriorating.

  In the present embodiment, when the out-of-service state is detected and the stop state is detected, the parameter selection unit 144 selects the communication parameter so as to reduce the power consumption even if the remaining battery amount exceeds a predetermined amount. To do. Specifically, when the out-of-service state is detected and the stop state is detected, the parameter selection unit 144 reduces the frequency of base station search execution even if the remaining battery capacity exceeds a predetermined amount. Select the communication parameter.

  That is, when the mobile communication terminal 100 is in an out-of-service state and in a stopped state, improvement in reception quality cannot be expected. Therefore, power consumption can be reduced by reducing the frequency of performing a base station search (full wave search). It is prevented from being wasted. In the existing method, a full wave search is executed at a fixed period when out of service area, but in this embodiment, the frequency of the full wave search can be reduced to reduce power consumption. For this reason, the operable time of the mobile communication terminal 100 can be further extended.

(6) Other Embodiments As described above, the present invention has been described according to the embodiment. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, the display unit 150 may display the communication parameter selected by the parameter selection unit 144, and the input unit 160 may accept a user operation for changing the communication parameter selected by the parameter selection unit 144. In this case, the display unit 150 configures a notification unit that notifies the user of the communication parameter selected by the parameter selection unit 144. Note that the notification is not limited to display but may be notification by voice. The input unit 160 configures an operation receiving unit that receives a user operation for changing a communication parameter.

  As a result, communication parameters can be set according to user operations, and user convenience can be improved. Alternatively, as shown in FIG. 7, all communication parameters may be selected by user operation. In the example of FIG. 7, information indicating the remaining battery level and information indicating communication parameter setting candidates (here, initial setting, power consumption priority, reception quality priority) are displayed on the display unit 150.

  In the embodiment described above, the parameter selection unit 144 selects the communication parameter in consideration of not only the speed information and the remaining battery level but also the reception quality. However, the communication parameter is selected based only on the speed information and the remaining battery level. You may choose. Alternatively, since the moving speed of the mobile communication terminal 100 and the reception quality have a correlation, a configuration using the reception quality as speed information can also be employed.

  In the embodiment described above, when the out-of-service state is detected and the stop state is detected, the communication parameter is selected so as to reduce the power consumption even if the remaining battery amount exceeds a predetermined amount. However, when the remaining battery capacity exceeds a predetermined amount, the communication parameter may always be selected with priority given to improving the reception quality.

  In the above-described embodiment, the configuration for selecting and updating the values of the communication parameters illustrated in FIG. 4 has been described. However, the communication parameters that affect the reception quality and power consumption are not limited to the communication parameters illustrated in FIG. If so, communication parameters other than the communication parameters shown in FIG. 4 may be selected and updated.

  In the embodiment described above, the movement state of the mobile communication terminal 100 is divided into three states of stop, low speed, and high speed, but it may be divided into two, stop and movement. In this case, in the flowchart illustrated in FIG. 6, it may be determined whether or not the user is moving in step S <b> 110, and the process may be advanced to step S <b> 111 when it is determined that the user is moving.

  In addition, the moving speed of the mobile communication terminal 100 is about 51 km / h to 200 km / h as high speed (moving). However, the moving speed of the mobile communication terminal 100 may be 100 km / h or higher (assuming movement on a bullet train or a highway) and high speed.

  Thus, it should be understood that the present invention includes various embodiments and the like not described herein. Therefore, the present invention is limited only by the invention specifying matters in the scope of claims reasonable from this disclosure.

1 is an overall schematic configuration diagram of a mobile communication system according to an embodiment of the present invention. It is a block diagram which shows schematic hardware structure of the mobile communication terminal which concerns on embodiment of this invention. It is a block diagram which shows the functional block structure of the control part of the mobile communication terminal which concerns on embodiment of this invention. It is a figure for demonstrating the specific example of the communication parameter which concerns on embodiment of this invention. It is a figure for demonstrating schematic operation | movement of the parameter selection part which concerns on embodiment of this invention. It is a flowchart which shows the detailed operation example of the mobile communication terminal which concerns on embodiment of this invention. It is a figure for demonstrating the parameter selection method which concerns on other embodiment.

Explanation of symbols

Mobile communication system 10, mobile communication terminal 100, radio base stations 200A and 200B, antenna 110, transmission / reception unit 120, battery 130, control unit 140, movement speed information acquisition unit 141, battery remaining amount detection unit 142, reception quality measurement unit 143, parameter selection unit 144, parameter setting unit 145, display unit 150, input unit 160, microphone 170, speaker 180

Claims (7)

A transmission / reception unit for transmitting / receiving a radio signal to / from a radio base station;
A mobile communication terminal having at least a battery for storing power supplied to the transceiver unit,
A speed information acquisition unit for acquiring speed information indicating a moving speed of the mobile communication terminal;
A remaining battery level detection unit for detecting a remaining battery level that is the remaining power level stored in the battery;
Based on the speed information acquired by the speed information acquisition unit and the remaining battery level detected by the remaining battery level detection unit, the reception quality of the radio signal and the power consumption of the transmission / reception unit are affected. A parameter selection unit for selecting at least one communication parameter;
A parameter setting unit that sets the communication parameter selected by the parameter selection unit in the transmission / reception unit;
The parameter selection unit selects the communication parameter so as to reduce the power consumption when the remaining battery level is less than a predetermined amount.   The mobile communication terminal according to claim 1, wherein the parameter selection unit selects the communication parameter so as to increase the reception quality when the remaining battery capacity exceeds a predetermined amount. A reception quality measuring unit that measures the reception quality of the radio signal received by the transceiver from the radio base station;
The said parameter selection part selects the said communication parameter based on the said reception quality measured by the said reception quality measurement part in addition to the said speed information and the said battery remaining charge. Mobile communication terminals. The parameter selection unit
Based on the received quality, the mobile communication terminal detects an out-of-service state that is located outside the radio wave coverage from the radio base station,
Based on the speed information, detecting a stop state in which the mobile communication terminal is not moving,
When the out-of-service state is detected and the stop state is detected, the communication parameter is selected so as to reduce the power consumption even if the remaining battery capacity exceeds the predetermined amount. The mobile communication terminal according to claim 3. A notification unit for notifying a user of the communication parameter selected by the parameter selection unit;
An operation receiving unit that receives a user operation to change the communication parameter selected by the parameter selection unit;
The mobile communication terminal according to claim 1, wherein the parameter setting unit sets the communication parameter according to the user operation when the operation receiving unit receives the user operation. The transmitting / receiving unit performs a base station search that is an operation of searching for a radio base station having the highest reception quality from among the plurality of radio base stations,
The transceiver unit is
If the communication parameter is selected to increase the reception quality, increase the frequency of performing the base station search,
The mobile communication terminal according to claim 1, wherein, when the communication parameter is selected so as to reduce the power consumption, the frequency of executing the base station search is decreased. A transmission / reception unit for transmitting / receiving a radio signal to / from a radio base station;
A control method for controlling a mobile communication terminal having at least a battery for storing power supplied to the transceiver unit,
Obtaining speed information indicating a moving speed of the mobile communication terminal;
Detecting a remaining battery level, which is a remaining power level stored in the battery;
Based on the speed information acquired by the acquiring step and the remaining battery level detected by the detecting step, at least one that affects reception quality of the radio signal and power consumption of the transmission / reception unit Selecting communication parameters;
Setting the communication parameter selected in the selecting step in the transmission / reception unit,
In the selecting step, the communication parameter is selected so as to reduce the power consumption when the remaining battery level is less than a predetermined amount.

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