JP2015070585A - Communication terminal and program - Google Patents

Abstract

An object of the present invention is to obtain a highly reliable radio wave intensity value while moving.
A communication terminal capable of receiving a radio wave, a measurement unit that measures a radio wave intensity value representing the intensity of the received radio wave, an acquisition unit that acquires a moving speed of the communication terminal, and the measured radio wave There is provided a communication terminal having a correction unit that corrects the radio wave intensity value using an intensity value and the acquired moving speed.
[Selection] Figure 2

Description

  The present invention relates to a communication terminal and a program.

  Conventionally, RSSI (Received Signal Strength Indication) has been widely used as a value representing radio wave intensity. The RSSI indicates that the larger the value is, the stronger the radio wave intensity is, and the smaller the value is, the weaker the radio field intensity is.

  First, there is an application for improving communication quality. For example, Patent Document 1 discloses that a mobile phone measures the radio wave intensity of radio waves emitted from a plurality of base stations at the start of a call, compares the moving average value of RSSI for each base station, and the base of which the change is gradual. A technology to preferentially connect to stations is proposed. Patent Document 2 measures the strength of radio waves emitted from a connected base station during a call, and switches the connection to another base station when the moving average value of RSSI is less than a threshold. Proposing technology. Any of the inventions described in these patent documents bring about an effect of stabilizing the call quality.

  Secondly, there is an application for specifying the current location of the mobile terminal. For example, in Patent Document 3, a radio wave having a constant intensity is periodically transmitted from a mobile terminal, a plurality of base stations placed in the vicinity sequentially measure the radio field intensity, and a moving average value of RSSI for each base station is measured. A method for estimating the current location of the mobile terminal from the ratio is proposed.

  All of the techniques described in the above-mentioned patent documents use a moving average of RSSI that is a measurement result of a plurality of times, instead of RSSI obtained by a single measurement result. This is to remove the RSSI temporal fluctuation caused by multipath fading.

  In the conventional technique, the RSSI is obtained using a predetermined moving average calculation formula regardless of the moving speed. However, when the mobile terminal is moving, the RSSI time variation is more affected by the change in the distance from the radio wave source than the effect of multipath fading. Therefore, if the RSSI is calculated uniformly considering mainly the influence of multipath fading as in the past, an incorrect RSSI moving average value may be obtained depending on the moving speed. was there.

  The present invention has been made in view of such a problem, and an object thereof is to obtain a highly reliable radio wave intensity value during movement.

In order to solve the above-described problems and achieve the object, a communication terminal according to an embodiment of the present invention,
A communication terminal capable of receiving radio waves,
A measurement unit for measuring a radio wave intensity value indicating the intensity of the received radio wave;
An acquisition unit for measuring the moving speed of the communication terminal;
A correction unit that corrects the radio field intensity value using the measured radio field intensity value and the measured moving speed;
Have

  According to the present invention, a highly reliable radio wave intensity value can be obtained during movement.

The hardware block diagram of the communication terminal which concerns on one Embodiment of this invention. The functional block diagram of the communication terminal which concerns on one Embodiment of this invention. The figure showing the example of the table which stores coefficient information. The flowchart which shows the process which calculates an electromagnetic wave intensity value. The sequence diagram which shows the process which calculates an electromagnetic wave intensity value. The functional block diagram of the communication terminal which concerns on one Embodiment of this invention. The figure showing the example of the table which stores coefficient information. The sequence diagram which shows the process which calculates an electromagnetic wave intensity value. The functional block diagram of the communication terminal which concerns on one Embodiment of this invention. The figure showing the example of the table which stores algorithm information. The flowchart which shows the process which calculates an electromagnetic wave intensity value. The sequence diagram which shows the process which calculates an electromagnetic wave intensity value. The figure showing the positional relationship of a radio wave transmission source and a radio wave reception point. The figure showing the relationship between theoretical distance and received radio wave intensity. The figure showing the relationship between an actual distance and received radio wave intensity. The figure showing transition of a received field strength value. The figure showing transition of the moving average of a received electric wave strength value.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1. Outline 2. 2. Hardware configuration Function 4. Example of operation 5. Modified example

≪ １． Overview ≫
First, the outline | summary of this invention is demonstrated using FIGS. 13-17.

  In a space where there are no obstacles, it is known that radio waves emitted from a point source weaken in inverse proportion to the square of the distance (the inverse square law). FIG. 13 shows a radio wave source and points A, B, C, and D that are a certain distance away from the radio wave source. FIG. 14 shows the values of the radio field intensity (hereinafter referred to as “received radio field intensity values”) measured by receiving radio waves transmitted from the radio wave source on the straight line connecting points A, B, C, and D. Represents.

  However, since various obstacles are scattered in the space, radio waves are reflected everywhere and they interfere with each other. As a result, the received radio wave intensity value is subject to fluctuations in time (this is called multipath fading), and the actual measurement result of the received radio wave intensity value is as shown in FIG. Although it can be confirmed that the inverse square law has an influence on the characteristics of the received radio wave intensity value shown in FIG. 15, it can be seen that the distribution of the received radio wave intensity value is caused by multipath fading. That is, the received radio wave intensity value at a certain place is determined by both the inverse square law and multipath fading.

In order to remove the time fluctuation of the received radio wave intensity value due to such multipath fading, a moving average of the received radio wave intensity values (hereinafter referred to as “moving average radio wave intensity value”) is obtained by the following equation. .

Out (t) = W ₀ × ln (t) + W ₁ × ln (t−1) + W ₂ × ln (t−2)
+ ...
... Formula (1)

Here, Out (t) represents a moving average radio wave intensity value at the current time, and ln (t) represents a received radio wave intensity value obtained by measurement at the current time. Further, ln (t−n) represents a received radio wave intensity value measured n times before (n is an integer of 0 or more), and W _n is a weighting coefficient of the n-th term on the right side (n is an integer of 0 or more). ). For example, when the received radio wave intensity value as shown in FIG. 16 is obtained, the moving average radio wave intensity value obtained using the above equation (1) is as shown in FIG.

  The communication terminal according to an embodiment of the present invention prepares a set of weighting factors according to the moving speed in advance, and uses the weighting factor according to the measured moving speed to appropriately move according to the moving speed. Find the average field strength value. Here, in general, as the moving speed of the communication terminal increases, the time fluctuation of the received radio wave intensity value is more affected by the change in the distance from the radio wave source than the effect of multipath fading. Therefore, when the moving speed of the communication terminal is high, the ratio of the received radio wave intensity value measured in the past to the moving average radio wave intensity value is reduced. That is, the higher the moving speed, the smaller the weight coefficient of the old received radio wave intensity value and the larger the weight coefficient of the new received radio wave intensity value. As a result, the communication terminal according to the embodiment of the present invention can acquire a highly reliable moving average radio wave intensity value even when moving.

≪ 2. Hardware configuration ≫
FIG. 1 is an example of a hardware configuration of a communication terminal 10 according to an embodiment of the present invention. The communication terminal 10 illustrated in FIG. 1 is a device such as a smartphone, a mobile phone, a laptop, a tablet, or a portable game machine. In another embodiment, the communication terminal 10 may be provided by being incorporated in a transportation means such as an automobile or a railway, or an electronic device such as a television or radio.

  The communication terminal 10 connects the CPU 100, the ROM 102, the RAM 104, the wireless communication device 106, the antenna 108, the speed sensor 110, the wired communication device 112, the display device 114, the input device 116, and these devices. And a bus 118.

  The CPU 100 is an arithmetic device that controls the operation of the communication terminal 10. The ROM 102 is a memory that stores a program executed by the CPU 100, data necessary for the operation of the program, and data output by the program. The ROM 102 may be a rewritable memory such as an EEPROM (Electrically Erasable Programmable Read-Only Memory). The RAM 104 is a memory used as a work area for the CPU 100.

  The wireless communication device 106 is a communication device that can receive radio waves transmitted from a base station, an access point, a satellite, other communication devices, and the like through the antenna 108. The wireless communication device 106 may be a communication module capable of communicating with a 3G or 4G network base station, or may be a wireless LAN module capable of communicating with a wireless LAN access point. The wireless communication device 106 may be a communication module that performs communication in accordance with a wireless communication standard such as Bluetooth (registered trademark) or ZigBee (registered trademark). The wireless communication device 106 may be a receiver that receives broadcasting radio waves, such as terrestrial digital broadcasting and satellite broadcasting. The wireless communication device 106 may be an arbitrary communication module that can receive radio waves in an arbitrary frequency band.

  The speed sensor 110 is a sensor that can measure the moving speed of the communication terminal 10. For example, the speed sensor 110 is an arbitrary sensor that can measure the speed of the communication terminal 10 such as an acceleration sensor, an angular speed sensor, or a vehicle speed sensor.

  The wired communication device 112 is a communication device that communicates with an external device through, for example, a dedicated cable or a LAN cable. The display device 114 is a display device that presents information to the user, such as a liquid crystal display. The input device 116 is an input device that accepts input from the user, such as a touch panel and buttons.

  Note that the communication terminal 10 may not include the wired communication device 112, the display device 114, and the input device 116. For example, in another embodiment, when the communication terminal 10 is provided by being incorporated in a transportation means, an electronic device, or the like, the communication terminal 10 may not include the display device 114 and the input device 116. In such an embodiment, the speed sensor 110 may be provided outside the communication terminal 10. In this case, the communication terminal 10 may be configured to receive speed information from the speed sensor 110 provided outside, for example, via the wired communication device 112.

≪ 3. Function ≫
FIG. 2 is a functional block diagram of the communication terminal 10 according to the embodiment of the present invention. FIG. 2 shows elements that are particularly relevant to the description of the present embodiment, among various elements included in the communication terminal 10. The communication terminal 10 includes a storage unit 200, a reception unit 202, a radio wave intensity value measurement unit 204, a time acquisition unit 206, a storage unit 208, a moving speed acquisition unit 210, a selection unit 212, and a calculation unit 214. And an output unit 216.

  The storage unit 200 is realized by the ROM 102 illustrated in FIG. 1 and stores programs and data related to the operation of the communication terminal 10. In particular, the storage unit 200 stores coefficient information 250, received radio wave intensity value history information 252, and moving average radio wave intensity value 254.

  The coefficient information 250 is information that associates a set of weight coefficients used in the above-described equation (1) for each moving speed. The coefficient information 250 is stored in, for example, a table illustrated in FIG. The coefficient information 250 in FIG. 3 includes items of a set of moving speed and coefficient. The moving speed represents the measured moving speed of the communication terminal 10, and the unit is meter per second. In the example of FIG. 3, a set of four weighting factors each having 10 weighting factors is defined in accordance with the moving speed. That is, a moving average received intensity value is calculated using received radio field intensity values obtained by 10 measurements.

As the moving speed increases, the weighting factor (W ₀ ) multiplied by the recently acquired received radio wave intensity value is set to a larger value. On the other hand, when the moving speed is extremely low (that is, when it can be regarded as not moving), the same value is set for all the weighting factors. This is because the ratio of the contribution of the recently acquired received radio wave intensity value to the moving average radio wave intensity value is increased in view of the fact that the inverse square law has a great influence on the received radio wave intensity value during high-speed movement.

  In the example of FIG. 3, four sets of weighting factors and 10 weighting factors are used, but any number of pairs and weighting factors may be used. Further, the value of the weighting factor may be arbitrarily changed according to the system to which the communication terminal 10 is applied.

  The received radio wave intensity value history information 252 is information for storing the measured received radio wave intensity value together with the acquisition time. For example, the received radio wave intensity value history information 252 includes a number (for example, 10) of received radio wave intensity values corresponding to the number of weighting factors.

  The moving average radio wave intensity value 254 is a moving average radio wave intensity value obtained by Expression (1). The moving average radio wave intensity value 254 may be the latest moving average radio wave intensity value or may include a history of the latest and past moving average radio wave intensity values.

  The receiving unit 202 is realized mainly by the processing of the wireless communication device 106 and the antenna 108 shown in FIG. 1, converts radio waves transmitted from other base stations or devices into electrical signals, and generates electrical signals as necessary. The signal is amplified to extract a frequency component necessary for measuring the received radio wave intensity value. The receiving unit 202 passes the extracted electrical signal of the frequency component to the radio wave intensity value measuring unit 204.

  The radio field intensity measurement unit 204 is realized mainly by the processing of the wireless communication device 106 shown in FIG. 1, measures the power of the electrical signal received from the reception unit 202, and generates a voltage proportional to the logarithm of the power. To do. The radio wave intensity value measuring unit 204 measures a received radio wave intensity value (RSSI) by quantizing the generated voltage. The radio wave intensity value measuring unit 204 passes the received radio wave intensity value acquired by measurement to the storage unit 208.

  The time acquisition unit 206 is mainly realized by the processing of the CPU 100 shown in FIG. 1 and acquires the current time. The time acquisition unit 206 passes the acquired current time to the storage unit 208.

  The storage unit 208 is mainly realized by the processing of the CPU 100 shown in FIG. Upon receiving the received radio wave intensity value from the radio wave intensity value measuring unit 204, the storage unit 208 acquires the current time from the time acquisition unit 206, and sets the received radio wave intensity value and the current time as received radio wave intensity value history information 252. And stored in the storage unit 200.

  The moving speed acquisition unit 210 is realized mainly by the processing of the speed sensor 110 and the CPU 100 shown in FIG. 1 and acquires the current moving speed of the communication terminal 10. For example, when the speed sensor 110 is an acceleration sensor, the moving speed can be acquired by integrating the acceleration acquired from the acceleration sensor and removing noise applied from the outside. When the speed sensor 110 is a vehicle speed sensor, the moving speed can be acquired by measuring a pulse signal proportional to the rotational speed of the axle. Since the calculation method of the moving speed using the various speed sensors 110 is known, description here is abbreviate | omitted. The movement speed acquisition unit 210 passes the acquired movement speed to the selection unit 212.

  In addition, when the speed sensor 110 is provided outside the communication terminal 10 (for example, a vehicle speed sensor in an automobile), the moving speed acquisition unit 210 obtains information obtained from the outside via the wired communication device 112, for example. The movement speed may be acquired based on the above. Alternatively, the moving speed acquisition unit 210 may acquire the moving speed information itself from another device provided outside.

  The selection unit 212 is realized mainly by the processing of the CPU 100 shown in FIG. 1, refers to the coefficient information 250 stored in the storage unit 200, and sets the weighting coefficient corresponding to the moving speed received from the moving speed acquisition unit 210. Select a pair. The selection unit 212 passes the selected set of weighting factors to the calculation unit 214.

  The calculation unit 214 is mainly realized by the processing of the CPU 100 shown in FIG. Calculation unit 214 reads received radio wave intensity value history information stored in storage unit 200. Then, the calculation unit 214 calculates a moving average radio wave intensity value using the read received radio wave intensity value and the weighting coefficient received from the selection unit 212 according to equation (1). The calculation unit 214 stores the calculated moving average radio wave intensity value in the storage unit 200. When the communication terminal 10 is configured to output the calculated moving average radio wave intensity value to the outside, the calculation unit 214 may pass the calculated moving average radio wave intensity value to the output unit 216. .

  The received radio field strength value is corrected to a moving average radio field strength value suitable for improving communication quality and specifying the current position by the functions of the selection unit 212 and the calculation unit 214 described above. The calculation unit 214 is collectively referred to as a correction unit 218.

  The output unit 216 is realized mainly by the processing of the display device 114 or the wired communication device 112 shown in FIG. 1 and displays the moving average radio wave intensity value received from the calculation unit 214 on the display device 114, or You may transmit to an external apparatus.

<< 4. Example of operation ≫
FIG. 4 is a flowchart showing the processing flow of the communication terminal 10 according to the embodiment of the present invention.

  First, the receiving unit 202 receives radio waves transmitted from other base stations or devices (step S101). Next, the radio wave intensity value measuring unit 204 measures the received radio wave intensity value of the radio wave received in step S101 (step S102). Then, the storage unit 208 stores the received radio wave intensity value acquired in step S102 in the storage unit 200 together with the current time (step S103).

  Next, the moving speed acquisition unit 210 acquires the current moving speed of the communication terminal 10 (step S104). Next, the selection unit 212 refers to the coefficient information 250 stored in the storage unit 200, and selects a set of weighting factors corresponding to the moving speed acquired in Step S104 (Step S105). Then, the calculation unit 214 calculates a moving average radio field intensity value using the received radio field intensity value included in the received radio field intensity value history information and the weighting factor selected in Step S105 (Step S106). Further, the output unit 216 outputs the moving average radio wave intensity value calculated in step S106 to, for example, the display device 114 (step S107).

  FIG. 5 is a sequence diagram illustrating an operation example of the communication terminal 10 according to the embodiment of the present invention.

  First, the receiving unit 202 receives radio waves transmitted from other base stations or devices (step S201). Next, the receiving unit 202 passes an electric signal obtained by converting the received radio wave to the radio wave intensity value measuring unit 204 (step S202). Next, the radio wave intensity value measuring unit 204 measures the received radio wave intensity value of the radio wave using the received electrical signal (step S203). Then, the radio wave intensity value measurement unit 204 passes the measured received radio wave intensity value to the storage unit 208 (step S204).

  The storage unit 208 receives the current time from the time acquisition unit 206 (step S205). Next, the storage unit 208 stores the received radio wave intensity value received in step S204 and the time received in step S205 in association with each other in the storage unit 200 (step S206).

The movement speed acquisition unit 210 acquires the current movement speed of the communication terminal 10 (step S207). Next, the movement speed acquisition unit 210 passes the acquired movement speed to the selection unit 212 (step S208). The selection unit 212 reads coefficient information from the storage unit 200 (step S209). Then, the selection unit 212 selects a set of weighting factors according to the moving speed received in step S208 (step S210). For example, when the current moving speed of the communication terminal 10 is 3.0 meters per second, the selection unit 212 sets the coefficient set (W ₀ = 0.2, W ₁ ) of the second entry from the top in FIG. = W ₂ =... = 0.1, W ₉ = 0).

  The selection unit 212 passes the coefficient selected in step S210 to the calculation unit 214 (step S211). Next, the calculation unit 214 reads the received radio wave intensity value history information 252 from the storage unit 200 (step S212). Then, the calculation unit 214 calculates a moving average radio wave intensity value by using the set of coefficients received in step S211 and the received radio wave intensity value read in step S212 according to equation (1) (step S213).

The calculation unit 214 stores the calculated moving average radio wave intensity value in the storage unit 200 (step S214). The calculation unit 214 passes the calculated moving average radio wave intensity value to the output unit 216 (step S215). Then, the output unit 216 outputs the received moving average radio wave intensity value to the display device 114 (step S216).
Through the above processing, the communication terminal 10 according to the present embodiment changes the weighting coefficient by which the past received radio wave intensity value is multiplied according to the moving speed, so that the moving average radio wave having high reliability even during movement. An intensity value can be calculated.

<< 5. Modified example ≫
The communication terminal 10 in the embodiment described above calculates the moving average radio wave intensity value by changing the coefficient according to the moving speed based on the equation (1). In the following, an example in which the radio wave intensity value is calculated by a method different from the formula (1) (modified example 1) and an example in which the formula (algorithm) for calculating the radio wave intensity value according to the moving speed is changed (modified example 2). explain.

<< Modification 1 >>
First, an example of the communication terminal 10A that calculates the radio field intensity value by a method different from the equation (1) will be described. Communication terminal 10 </ b> A in the present modification obtains a radio wave intensity value (hereinafter referred to as a calculated radio wave intensity value) using the following formula (2).

Out (t) = W ₀ × ln (t) + W ₁ × Out (t−1) (2)

Here, Out (t) represents a calculated radio wave intensity value at the current time, ln (t) represents a received radio wave intensity value obtained by measurement at the current time, and W _n is a weighting factor of the n-th term on the right side. (N is 0 or 1). Here, Out (t−1) is the calculated radio wave intensity value calculated last time. That is, the calculated radio wave intensity value is a value that follows the time variation of the received radio wave intensity. The two weighting factors represent the mixing ratio between the received radio wave intensity value measured this time and the calculated radio wave intensity value calculated last time. Therefore, the follow-up speed can be changed by changing the mixing ratio of the two. Specifically, if W ₀ is increased, the tracking speed is increased, and if W ₁ is increased, the tracking speed is decreased.

  By calculating the calculated radio wave intensity value using the equation (2), the received radio wave intensity value history information 252 in the storage unit 200 becomes unnecessary, which contributes to the reduction in the capacity of the ROM 102. The communication terminal 10 </ b> A in this modification is particularly effective in a situation where it is difficult to ensure the capacity of the ROM 102.

  FIG. 6 is a functional block diagram of the communication terminal 10A in the present modification. Unlike the functional block of FIG. 2, the received radio field strength history information 252 is not stored in the storage unit 200, but the received radio field strength value 252 </ b> A is stored instead. The storage unit 200 stores a calculated radio wave intensity value 254A instead of the moving average radio wave intensity value 254.

Also, in the coefficient information 250A in the present modification, a plurality of sets of two weighting coefficients are defined according to the moving speed, as illustrated in FIG. The value of the weighting factor can be set as appropriate according to the system to which the communication terminal 10A is applied. However, it should be noted that as the moving speed increases, the weighting factor (W ₀ ) multiplied by the received radio wave intensity value measured this time is set to a larger value. On the other hand, when the moving speed is extremely low (that is, when it can be regarded as not moving), a large value is set to the weighting coefficient (W ₁ ) multiplied by the previously calculated calculated radio wave intensity value. This is to increase the ratio of the contribution of the received radio wave intensity value acquired this time, considering that the inverse square law has a large influence on the received radio wave intensity value during high-speed movement.

  In addition, as described above, the calculation unit 214A in the present modification includes a set of coefficients selected according to the moving speed based on the equation (2), the received radio wave intensity value 252A, and the previous calculated radio wave intensity value 254A. Are used to calculate the calculated radio wave intensity value.

  The processing flow of the communication terminal 10A in the present modification is the same as the processing illustrated in FIG.

  FIG. 8 is a sequence diagram illustrating an operation example of the communication terminal 10A according to the present modification.

  First, Steps S301 to S306 from when the communication terminal 10A receives a radio wave until the received radio wave intensity is stored are the same as Steps S201 to S206 in FIG. Further, Steps S307 to S311 for specifying a set of coefficients after the communication terminal 10A acquires the moving speed are the same as Steps S207 to S211 in FIG.

  The calculation unit 214A of the communication terminal 10A in the present modification reads the previous calculated radio wave intensity value 252A from the storage unit 200 (step S312). Then, the calculation unit 214 calculates a calculated radio wave intensity value by using the coefficient set received in step S311 and the received radio wave intensity value read in step S312 according to equation (2) (step S313).

The calculation unit 214 stores the calculated calculated radio wave intensity value in the storage unit 200 (step S314). The calculation unit 214 passes the calculated calculated radio wave intensity value to the output unit 216 (step S315). Then, the output unit 216 outputs the received calculated radio wave intensity value to the display device 114 (step S316).
Through the above processing, the communication terminal 10A in the present embodiment can calculate a highly reliable radio wave intensity value according to the moving speed even when the memory capacity is severely limited.

<< Modification 2 >>
Next, an example of the communication terminal 10B that changes the equation for calculating the radio wave intensity value according to the moving speed will be described. The communication terminal 10B in the present modification can acquire the moving speed in the same manner as the communication terminal 10 described above, but unlike the communication terminal 10, an expression (algorithm) for calculating the radio wave intensity value according to the moving speed. Can be selected. The communication terminal 10B in the present modification example can calculate the radio wave intensity value corresponding to the moving speed more flexibly by making the expression selectable (the calculated radio wave intensity value is calculated as the calculated radio wave intensity value). Called).

For example, a plurality of expressions (algorithms) such as the following may be selectable.
-An expression in which the number of terms on the right side (that is, the number of received radio wave intensity values used in the calculation) in Expression (1) is different-Expression (1) and Expression (2) described above
In addition, using the current and past received radio field strength values obtained by measurement, it is possible to select any of several formulas that calculate the calculated radio field strength values used to improve communication quality and estimate the current position. obtain.

  FIG. 9 is a functional block diagram of the communication terminal 10B in the present modification. Unlike the functional block of FIG. 2, algorithm information 256 is further stored in the storage unit 200.

  As illustrated in FIG. 10, the algorithm information 256 is information that associates a moving speed with an algorithm number that identifies an algorithm used to calculate a calculated radio wave intensity value. Here, two algorithm numbers are defined, but any number of algorithms may be defined.

  In addition, the coefficient information 250B in the present modified example associates the moving speed with the weighting coefficient multiplied by the received radio wave intensity value, as illustrated in FIG. Here, the coefficient information 250B can be prepared for each algorithm number defined in FIG.

  The selection unit 212B in the present modification example refers to the algorithm information 256 and selects an algorithm number corresponding to the movement speed acquired by the movement speed acquisition unit 210. Furthermore, the selection unit 212B refers to the coefficient information 250B and selects a set of coefficients corresponding to the moving speed. The selection unit 212B passes the selected algorithm number and coefficient pair to the calculation unit 214B.

  The calculation unit 214B in the present modification specifies an algorithm (expression) associated with the algorithm number received from the selection unit 212B. Then, the calculation unit 214B calculates a calculated radio wave intensity value using the set of coefficients received from the selection unit 212B based on the identified formula. The calculation unit 214B stores the calculated radio wave intensity value in the storage unit 200 and passes it to the output unit 216.

  FIG. 11 is a flowchart showing the processing flow of the communication terminal 10B in this modification.

  First, Steps S401 to S404 from when the communication terminal 10B receives a radio wave until the movement speed is acquired are the same as Steps S101 to S104 in FIG.

  Next, the selection unit 212B refers to the algorithm information 256 stored in the storage unit 200, and selects an algorithm number corresponding to the moving speed acquired in step S404 (step S405). Next, the selection unit 212B refers to the coefficient information 250B stored in the storage unit 200, and selects a set of weighting factors corresponding to the moving speed acquired in step S404 (step S406). Based on the algorithm (expression) corresponding to the selected algorithm number, the calculation unit 214B uses the received radio wave intensity value included in the received radio wave intensity value history information 252 and the selected coefficient pair to calculate the calculated radio wave. An intensity value is calculated (step S407). Further, the output unit 216 outputs the calculated radio wave intensity value calculated in step S106 to, for example, the display device 114 (step S408).

  FIG. 12 is a sequence diagram illustrating an operation example of the communication terminal 10B in the present modification.

  First, steps S501 to S506 from when the communication terminal 10B receives a radio wave until the received radio wave intensity is stored are the same as steps S201 to S206 in FIG. Further, Steps S507 to S508 in which the communication terminal 10B acquires the movement speed are the same as Steps S207 to S208 in FIG.

Subsequently, the selection unit 212B reads the algorithm information 256 from the storage unit 200 (step S509). Next, the selection unit 212B selects a set of algorithm numbers corresponding to the moving speed received in step S508 (step S510). For example, when the current moving speed of the communication terminal 10B is 3.0 meters per second, the selection unit 212B selects the algorithm number “1” of the top entry in FIG. Further, the selection unit 212B reads the coefficient information 250B from the storage unit 200 (step S511). Then, the selection unit 212 selects a set of weighting factors according to the moving speed received in step S508 (step S512). For example, when the moving speed of the current communication terminal 10B is 3.0 meters per second, the selection unit 212B sets the coefficient set (W ₀ = 0.2, W ₁ ) of the second entry from the top in FIG. = W ₂ =... = 0.1, W ₉ = 0).

  The selection unit 212B passes the algorithm number selected in step S510 and the coefficient selected in step S512 to the calculation unit 214B (step S513). Next, the calculation unit 214B reads the received radio wave intensity value history information 254 from the storage unit 200 (step S514). Based on the equation corresponding to the algorithm number “1” received in step S513, the calculation unit 214B calculates the calculated radio wave using the set of coefficients received in step S513 and the received radio wave intensity value read in step S514. An intensity value is calculated (step S515). Here, when the equation (1) is associated with the algorithm number “1” in advance, the calculation unit 214B uses ten received radio wave intensity values as in the example described with reference to FIG. The current moving average radio field strength value is calculated.

Next, the calculation unit 214B stores the calculated calculated radio wave intensity value in the storage unit 200 (step S516). In addition, the calculation unit 214B passes the calculated calculated radio wave intensity value to the output unit 216 (step S517). Then, the output unit 216 outputs the received calculated radio wave intensity value to the display device 114 (step S518).
Through the above processing, the communication terminal 10 according to the present embodiment changes the algorithm for calculating the radio wave intensity value and its coefficient according to the moving speed, thereby obtaining a highly reliable radio wave intensity value even during movement. Can be calculated.

  In addition, what applied the arbitrary combination of the component of this invention, expression, or a component to a method, an apparatus, a system, a computer program, a recording medium, etc. is also effective as an aspect of this invention. The present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims.

10 communication terminal 200 storage unit 202 reception unit 204 radio wave intensity value measurement unit 206 time acquisition unit 208 storage unit 210 movement speed acquisition unit 212, 212B selection unit 214, 214A, 214B calculation unit 216 output unit 218, 218A, 218B correction unit 250 250B Coefficient information 252 Received radio wave intensity value history information 252A Received radio wave intensity value 254, 254B Moving average radio wave intensity value 254A Calculated radio wave intensity value 256 Algorithm information

JP 2011-217225 A Japanese Patent Laid-Open No. 06-204559 Special table 2000-511369 gazette

Claims (10)

A communication terminal capable of receiving radio waves,
A measurement unit for measuring a radio wave intensity value indicating the intensity of the received radio wave;
An acquisition unit for acquiring the moving speed of the communication terminal;
A correction unit that corrects the radio field intensity value using the measured radio field intensity value and the acquired moving speed;
A communication terminal. Having a storage unit for storing one or more measured radio field intensity values;
The correction unit corrects the radio field intensity value by obtaining a moving average of the one or more radio field intensity values;
The communication terminal according to claim 1. The correction unit calculates a moving average value by multiplying each of the one or more radio field intensity values by one or more weighting factors,
The communication terminal according to claim 2. A plurality of sets of the one or more weighting factors are prepared according to the moving speed,
The correction unit selects the set of one or more weighting factors according to the moving speed;
The communication terminal according to claim 3. When the moving speed is equal to or higher than a predetermined value, the weighting factor multiplied by the radio wave intensity value acquired at a time closer to the current time is multiplied by the radio wave intensity value acquired at a time farther from the current time. A value greater than the weighting factor.
The communication terminal according to claim 4. When the moving speed is smaller than the predetermined value, the one or more weighting factors are the same value.
The communication terminal according to claim 5. The correction unit further corrects the radio wave intensity value by multiplying the corrected radio wave intensity value and the newly measured radio wave intensity value by a weighting factor,
The communication terminal according to claim 1. When the moving speed is equal to or higher than a predetermined value, the weighting factor multiplied by the newly measured radio wave intensity value is larger than the weighting factor multiplied by the corrected radio wave intensity value.
The communication terminal according to claim 7. When the moving speed is smaller than a predetermined value, the weighting factor multiplied by the newly measured radio wave intensity value is a value smaller than the weighting factor multiplied by the corrected radio wave intensity value.
The communication terminal according to claim 8. On the computer,
A measurement step for measuring a radio wave intensity value representing the intensity of the received radio wave;
An acquisition step for acquiring a moving speed;
A correction step of correcting the radio field intensity value using the measured radio field intensity value and the acquired moving speed;
The program to be executed.

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