Sensing device, sensing method, and program

Abstract

To provide a sensing device, etc. capable of performing sensing of a living body more accurately.SOLUTION: A sensing device 200 includes: an acquisition unit 230 for acquiring wireless machine information acquired from at least one wireless machine of a first wireless machine 100 disposed in an object space 400 capable of performing at least wireless transmission and a second wireless machine 201 disposed in the object space 400 capable of performing at least wireless reception; a determination unit 240 for determining whether or not a movable wireless machine of the first wireless machine 100 and the second wireless machine 201 is standing still; and a sensing unit 250 for performing sensing of a living body 300 in the object space 400 using CSI (channel state information) included in the wireless machine information that is received by the second wireless machine 201 from the first wireless machine 100 when the determination unit 240 determines that the movable wireless machine is standing still.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a sensing device, a sensing method, and a program for performing accurate sensing of a living body. [Background technology]

[0002] Methods using radio signals are being considered as a method for determining the location of a person, etc. For example, Patent Document 1 discloses a technology for estimating the location and state of a person to be detected by analyzing components including Doppler shift using differential calculations. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-117972 Summary of the Invention [Problem to be solved by the invention]

[0004] With conventional methods, it is difficult to perform high-precision biological sensing.

[0005] The present disclosure has been made in consideration of the above circumstances, and provides a sensing device and the like that can perform biological sensing with higher accuracy. [Means for solving the problem]

[0006] A sensing device according to one embodiment of the present disclosure includes an acquisition unit that acquires radio device information acquired by at least one of a first radio device that is arranged in a target space and is at least capable of wireless transmission, and a second radio device that is arranged in the target space and is at least capable of wireless reception; a determination unit that determines whether a mobile radio device of the first radio device or the second radio device is stationary based on the radio device information; and a sensing unit that, when the determination unit determines that the mobile radio device is stationary, senses a living body in the target space using CSI (Channel State Information) included in the radio device information, which CSI is received by the second radio device from the first radio device.

[0007] Furthermore, a sensing method according to one embodiment of the present disclosure is a sensing method executed by a sensing device, which acquires radio device information acquired by at least one of a first radio device arranged in a target space and capable of at least radio transmission, and a second radio device arranged in the target space and capable of at least radio reception, and determines whether a movable radio device of the first radio device and the second radio device is stationary based on the radio device information, and if it is determined in the determination that the movable radio device is stationary, senses a living body in the target space using CSI (Channel State Information) included in the radio device information, which CSI is received by the second radio device from the first radio device.

[0008] These general or specific aspects may be realized as a system, an integrated circuit, a computer program, or a recording medium such as a computer-readable CD-ROM, or may be realized as any combination of an apparatus, a system, a method, an integrated circuit, a computer program, and a recording medium. [Effects of the Invention]

[0009] According to the sensing device and the like according to the present disclosure, it is possible to perform sensing of a living body with higher accuracy. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram for explaining an outline of the sensing system according to the first embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of the sensing system according to the first embodiment. [Figure 3] FIG. 3 is a diagram for explaining the relationship between a transmission signal, a channel, and a reception signal. [Figure 4] FIG. 4 is a diagram for explaining propagation characteristics at each timing. [Figure 5] FIG. 5 is a flowchart showing an example of a sensing method performed by the sensing device according to the first embodiment. [Figure 6] FIG. 6 is a diagram illustrating an example of the configuration of a sensing system according to the second embodiment. [Figure 7] FIG. 7 is a diagram for explaining propagation characteristics at each timing. [Figure 8] FIG. 8 is a diagram showing the results of an experiment on an evaluation value for evaluating whether a wireless device is stationary based on CSI. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Findings that formed the basis of this disclosure) As a method for sensing a living body, a method using a radio signal is being considered.

[0012] In conventional technologies such as Patent Document 1, the transmitting device that transmits the wireless signal and the receiving device that receives the wireless signal are fixed, and no consideration is given to the movement of at least one of the transmitting device and the receiving device. When at least one of the transmitting device and the receiving device moves and changes position, the wireless signal is affected by the change in position, making it difficult to perform accurate biological sensing.

[0013] Therefore, the present inventors have come up with a sensing device that can perform sensing of a living body with high accuracy.

[0014] A sensing device according to a first aspect of the present disclosure includes an acquisition unit that acquires radio device information acquired by at least one of a first radio device arranged in a target space and capable of at least wireless transmission, and a second radio device arranged in the target space and capable of at least wireless reception; a determination unit that determines whether a mobile radio device of the first radio device or the second radio device is stationary based on the radio device information; and a sensing unit that, when the determination unit determines that the mobile radio device is stationary, senses a living body in the target space using CSI (Channel State Information) included in the radio device information, which CSI is received by the second radio device from the first radio device.

[0015] According to this, sensing within the target space is performed using CSI when the mobile radio device is stationary, so there is no need to consider the influence of movement by the mobile radio device, and therefore biological sensing can be performed with high accuracy.

[0016] A sensing device according to a second aspect of the present disclosure is the sensing device according to the first aspect, wherein the radio information further includes sensing information obtained by at least one of an acceleration sensor, an angular velocity sensor, and a GPS (Global Positioning System) sensor provided in the mobile radio, and the determination unit determines whether the mobile radio is stationary based on the sensing information.

[0017] According to this, whether or not the mobile radio device is stationary is determined based on sensing information obtained by at least one of an acceleration sensor, an angular velocity sensor, and a GPS sensor, so that whether or not the mobile radio device is stationary can be determined with high accuracy.

[0018] A sensing device according to a third aspect of the present disclosure is a sensing device according to the first or second aspect, further comprising a memory unit that stores a plurality of pieces of radio equipment information acquired over a certain period of time, and the determination unit determines whether the mobile radio equipment is stationary using an evaluation value calculated from a plurality of index values ​​based on a plurality of CSIs included in the plurality of pieces of radio equipment information, and each of the plurality of index values ​​is an index value for a specific index of CSI to which the index value corresponds among the plurality of CSIs.

[0019] This allows a determination as to whether a mobile radio device is stationary or not based on multiple CSIs stored for a certain period of time, so that even a radio device that does not have a sensor that can detect movement can be determined as being stationary or not.

[0020] A sensing device according to a fourth aspect of the present disclosure is the sensing device according to the third aspect, wherein the specific indicator includes an absolute value (amplitude) of CSI.

[0021] A sensing device according to a fifth aspect of the present disclosure is the sensing device according to the third or fourth aspect, wherein the specific indicator includes a phase of CSI.

[0022] A sensing device according to a sixth aspect of the present disclosure is the sensing device according to any one of the third to fifth aspects, wherein the specific indicator includes a correlation matrix of CSI.

[0023] A sensing device according to a seventh aspect of the present disclosure is the sensing device according to any one of the third to sixth aspects, wherein the evaluation value includes a variance or a covariance of the plurality of index values.

[0024] A sensing device according to an eighth aspect of the present disclosure is a sensing device according to any one of the third to sixth aspects, wherein the evaluation value includes at least one of the mean, median, mode, maximum and minimum values ​​of the plurality of index values ​​or the variance or covariance of the plurality of index values.

[0025] A sensing method according to a ninth aspect of the present disclosure is a sensing method executed by a sensing device, which acquires radio device information acquired by at least one of a first radio device arranged in a target space and capable of at least radio transmission, and a second radio device arranged in the target space and capable of at least radio reception, and determines whether a movable radio device of the first radio device and the second radio device is stationary based on the radio device information, and if it is determined in the determination that the movable radio device is stationary, senses a living body in the target space using CSI (Channel State Information) included in the radio device information, which CSI is received by the second radio device from the first radio device.

[0026] According to this, sensing within the target space is performed using CSI when the mobile radio device is stationary, so there is no need to consider the influence of movement by the mobile radio device, and therefore biological sensing can be performed with high accuracy.

[0027] A program according to a tenth aspect of the present disclosure is a program for causing a computer to execute the sensing method according to the ninth aspect.

[0028] The present disclosure may be realized not only as an apparatus, but also as an integrated circuit including the processing means of such an apparatus, as a method in which the processing means constituting the apparatus have steps, as a program that causes a computer to execute those steps, or as information, data, or signals indicating the program.These programs, information, data, and signals may be distributed via recording media such as CD-ROMs or communication media such as the Internet.

[0029] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that each of the embodiments described below represents a preferred specific example of the present disclosure. The numerical values, shapes, materials, components, component placement and connection configurations, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components that are not described in the independent claims that represent the highest concept of the present disclosure will be described as optional components that constitute a more preferred embodiment. Note that in this specification and drawings, components having substantially the same functional configuration will be assigned the same reference numerals to avoid redundant description.

[0030] (Embodiment 1) In the first embodiment, a method for determining whether a wireless device is stationary and sensing a living body when it is stationary will be described for a MIMO (Multiple-Input Multiple-Output) system in which both the transmitting antenna and the receiving antenna are multiple. The method can also be similarly applied to SIMO (Single-Input Multiple-Output) and MISO (Multiple-Input Single-Output) systems in which either the transmitting antenna or the receiving antenna is multiple.

[0031] [composition] FIG. 1 is a diagram for explaining an outline of the sensing system according to the first embodiment.

[0032] Specifically, FIG. 1 illustrates a first wireless device 100, a sensing device 200, and a living body 300. For example, the sensing system 1 includes the first wireless device 100 and the sensing device 200. The first wireless device 100 is a wireless device that is placed in a target space 400 and is capable of at least wireless transmission. The target space 400 is a space in which the first wireless device 100 and the sensing device 200 can sense the living body 300, and is a space that is a target of the sensing. The first wireless device 100 is a mobile wireless device. The first wireless device 100 is, for example, an autonomous vacuum cleaner. The first wireless device 100 is not limited to an autonomous vacuum cleaner, but may also be a mobile terminal such as a smartphone. The sensing device 200 may have a wireless function for receiving a wireless signal transmitted from the first wireless device 100, for example. The sensing device 200 is, for example, a router. The sensing device 200 is not limited to a router, but may also be a mobile terminal such as a smartphone.

[0033] In the sensing system 1, the first radio device 100 transmits a wireless signal to the sensing device 200. When transmitting the wireless signal, the first radio device 100 emits radio waves based on the radio signal into the target space 400. The radio waves emitted into the target space 400 are reflected by a living organism 300 in the target space 400. The sensing device 200 receives radio waves including the radio waves reflected by the living organism 300, and senses the living organism 300 based on the received radio waves. Sensing the living organism 300 includes detecting the position of the living organism 300 in the target space 400, identifying the living organism 300, determining whether the living organism 300 is present in the target space 400, specifying the movement of the living organism 300, and specifying the posture of the living organism 300. When determining the position of the living body 300 in the target space 400, the total distance between the first radio device 100 and the living body 300 and the distance between the living body 300 and the second radio device 200 may be calculated, or the direction (angle) of the living body 300 relative to the first radio device 100 may be determined, or the direction (angle) of the living body 300 relative to the second radio device 200 may be determined.

[0034] In addition, when sensing the living body 300, methods such as the MUSIC (MUltiple SIgnal Classification) method, the beamformer method, the Capon method, or other conventionally known methods may be used, and a sensor that realizes these functions may be provided in the first radio device 100 or the sensing device 200.

[0035] FIG. 2 is a diagram illustrating an example of the configuration of the sensing system according to the first embodiment.

[0036] The sensing system 1 includes a first radio device 100 and a sensing device 200.

[0037] The first radio device 100 includes a transmitting antenna unit 110, a transmitting unit 120, and a transmitting signal generating unit .

[0038] The transmitting antenna unit 110 has M transmitting antenna elements, where M is a natural number equal to or greater than 1. The M transmitting antenna elements transmit a multicarrier signal (transmitting wave) generated by the transmitting unit 120, which will be described later.

[0039] The transmission signal generating unit 130 generates a multicarrier signal in which a plurality of subcarrier signals are modulated. Specifically, the transmission signal generating unit 130 generates a plurality of subcarrier signals corresponding to a plurality of subcarriers in different frequency bands, and multiplexes the generated subcarrier signals to generate a multicarrier signal. In this embodiment, the transmission signal generating unit 130 generates an OFDM (Orthogonal Frequency Division Multiplexing) signal consisting of S subcarriers, which has high frequency band utilization efficiency, as a multicarrier signal. However, the transmission signal generating unit 130 is not limited to generating an OFDM signal in which the subcarriers are orthogonal, as long as the multicarrier signal is obtained by multicarrier modulation, and may generate other multicarrier signals such as a simple FDM (Frequency Division Multiplexing) signal.

[0040] Furthermore, the signal generated by the transmission signal generating unit 130 may be used in common with the signal used for communication.

[0041] The transmitter 120 performs appropriate processing on the signal generated by the transmission signal generator 130 to generate a transmission wave. Examples of processing performed here include up-conversion, which converts the signal from an intermediate frequency (IF) frequency band to a radio frequency (RF) frequency band, and amplification, which amplifies the signal to an appropriate transmission level. The transmitter 120 outputs the processed multicarrier signal to the transmitting antenna unit 110, causing the transmitting antenna unit 110 to transmit the multicarrier signal. As a result, the multicarrier signal is transmitted from M transmitting antenna elements provided in the transmitting antenna unit 110.

[0042] The sensing device 200 includes a receiving antenna unit 210, a receiving unit 220, an acquiring unit 230, a determining unit 240, a sensing unit 250, and a storage unit 260. Of these, the receiving antenna unit 210 and the receiving unit 220 function as a second radio device 201. In other words, in this embodiment, it can be said that the sensing device 200 includes the second radio device 201.

[0043] The receiving antenna unit 210 has N receiving antenna elements, where N is a natural number equal to or greater than 1. Note that when one of M and N is 1, the other is equal to or greater than 2. The N receiving antenna elements receive signals (received signals) transmitted from the M transmitting antenna elements and reflected by the living body 300.

[0044] The receiving unit 220 observes received signals received by N receiving antenna elements, including reflected signals resulting from the multicarrier signals transmitted from M transmitting antenna elements being reflected or scattered by the living organism 300, for a first period corresponding to a cycle resulting from the activity of the living organism 300. The cycle resulting from the activity of the living organism is a cycle resulting from the living organism (biological variation cycle) that is at least half a cycle of any one of the cycles of breathing, heartbeat, and body movement of the living organism 300. The received signals may include information about the transmitted signal that is the source of the received signals and that was transmitted by the first radio device 100. Note that the information about the transmitted signal that is the source of the received signals does not need to be included in the received signals, and may be transmitted from the first radio device 100 to the sensing device 200 by another means.

[0045] The receiver 220 converts the high-frequency signals received by the N receiving antenna elements into low-frequency signals that can be processed. The receiver 220 then demodulates the OFDM signal into S subcarrier signals. The S subcarrier signals are also called S IQ symbols. The S subcarrier signals are low-frequency signals.

[0046] The receiving unit 220 further calculates a plurality of complex transfer functions representing propagation characteristics between the transmitting antenna element and the receiving antenna element for each subcarrier from the S subcarrier signals obtained from the plurality of received signals observed over the first period. Note that the receiving unit 220 may constantly observe (or record) the received signals received by the receiving antenna unit 210 and acquire the S subcarrier signals continuously or periodically. In other words, the receiving unit 220 may acquire the S subcarrier signals at a plurality of different timings based on the received signals received at each timing.

[0047] Using the multiple received signals observed over a first period, the receiver 220 calculates multiple complex transfer functions representing propagation characteristics between the transmitting antenna elements and the receiving antenna elements in each of N×M combinations of M transmitting antenna elements and N receiving antenna elements, for each of multiple subcarriers to which multiple subcarrier signals correspond. Note that the N×M combinations are all possible combinations when M transmitting antenna elements and N receiving antenna elements are combined one-to-one.

[0048] In this embodiment, S subcarrier signals are used to calculate N×M×S sets of complex transfer functions representing propagation characteristics between each transmitting antenna element and each receiving antenna element for each of the S subcarrier signals. Note that the calculated complex transfer function matrix also includes reflected waves that do not pass through the living body 300, such as direct waves and reflected waves from fixed objects.

[0049] FIG. 3 is a diagram for explaining the relationship between a transmission signal, a channel, and a reception signal.

[0050] The transmission signal X transmitted from the transmitting antenna unit 110 propagates through the target space 400, is received by the receiving antenna unit 210, and is acquired as a received signal Y. The received signal Y received by the receiving antenna unit 210 is a signal that has changed as the transmission signal X propagates through the target space 400. Therefore, the received signal Y can be considered to be equal to a signal obtained by multiplying the propagation characteristic H of the space 400 by the transmission signal X. The propagation characteristic H is expressed by the above-mentioned N×M×S set of complex transfer functions.

[0051] FIG. 4 is a diagram for explaining propagation characteristics at each timing.

[0052] As described above, the propagation characteristics H have a complex transfer function for each combination of three types of parameters, i.e., for each receiving antenna element, each transmitting antenna element, and each subcarrier. That is, a different complex transfer function is calculated for each of the different multiple receiving antenna elements, a different complex transfer function is calculated for each of the different multiple transmitting antenna elements, and a different complex transfer function is calculated for each of the different multiple subcarriers.

[0053] 5 is a diagram showing an image of propagation characteristic H expressed by a combination of complex transfer functions when the number of receiving antenna elements is 3, the number of transmitting antenna elements is 4, and the number of subcarriers is 2, as shown in FIG. 4. In this case, propagation characteristic H can be expressed as a combination of 3x4x2 blocks. One block represents one complex transfer function calculated for one specific receiving antenna element, one specific transmitting antenna element, and one specific subcarrier. In this way, propagation characteristic H can be expressed three-dimensionally because it is expressed as a combination of three types of parameters: receiving antenna element, transmitting antenna element, and subcarrier. Furthermore, this three-dimensionally expressed propagation characteristic H is calculated for each of multiple timings.

[0054] Note that, with the subcarriers and transmitting antenna elements fixed, multiple complex transfer functions of different receiving antenna elements may be expressed as multiple complex transfer functions that differ in the receiving antenna element direction. Similarly, with the subcarriers and receiving antenna elements fixed, multiple complex transfer functions of different transmitting antenna elements may be expressed as multiple complex transfer functions that differ in the transmitting antenna element direction. Similarly, with the receiving antenna element and transmitting antenna element fixed, multiple complex transfer functions of different subcarriers may be expressed as multiple complex transfer functions that differ in the subcarrier direction. In this way, in the propagation characteristic H expressed three-dimensionally, the directions of each dimension may be expressed as the receiving antenna element direction, the transmitting antenna element direction, and the subcarrier direction using names related to three types of parameters.

[0055] For example, if the rows of a matrix representing propagation characteristic H are assigned to receiving antenna elements in a cubic matrix and the columns are assigned to transmitting antenna elements, then different propagation characteristics H are calculated for each subcarrier and for each timing of acquiring a received signal. That is, in this embodiment, from the S subcarrier signals transmitted from the receiving unit 220, the propagation characteristics H(s, t) between M transmitting antenna elements and N receiving antenna elements for the s-th subcarrier during the observation time t are expressed as a complex transfer function matrix, as shown in Equation 1.

[0056]

number

[0057] The acquiring unit 230 acquires radio equipment information including propagation characteristics H calculated by the receiving unit 220. The propagation characteristics H are an example of CSI (Channel State Information). The acquiring unit 230 acquires a plurality of pieces of radio equipment information over a certain period of time. That is, the acquiring unit 230 acquires radio equipment information at each of a plurality of timings over the certain period of time. The plurality of pieces of radio equipment information acquired by the acquiring unit 230 may be stored in the storage unit 260. The plurality of pieces of radio equipment information include a plurality of propagation characteristics H generated based on a plurality of received signals acquired at a plurality of consecutive timings.

[0058] The determination unit 240 determines whether the first radio device 100 is stationary based on the radio device information. Specifically, the determination unit 240 calculates an evaluation value based on multiple index values ​​based on multiple CSIs included in multiple pieces of radio device information stored in the storage unit 260. The evaluation value is an evaluation value for evaluating the variation in the multiple index values. For example, a larger evaluation value indicates a greater degree of variation in the multiple index values. Then, the determination unit 240 uses the calculated evaluation value to determine whether the first radio device 100, which is a mobile radio device, is stationary. The multiple index values ​​respectively correspond to multiple CSIs. In other words, the multiple index values ​​respectively correspond to multiple received signals obtained at multiple different timings. The multiple index values ​​represent changes in the received signals in time series.

[0059] Here, each of the multiple index values ​​is an index value of a specific index of the CSI to which the index value corresponds among the multiple CSIs. The specific index may be, for example, the absolute value (i.e., amplitude) of the CSI. In this case, the multiple index values ​​indicate multiple absolute values ​​(amplitudes) corresponding to the multiple CSIs, respectively. One index value indicating the absolute value is expressed as shown in Equation 2.

[0060]

number

[0061] In this case, the determination unit 240 calculates the variance in the time direction based on the absolute value, and calculates the maximum value of the variance as the evaluation value. The determination unit 240 determines whether the maximum value of the variance exceeds a predetermined threshold, and if the maximum value of the variance exceeds the predetermined threshold, determines that the first radio device 100 is moving. If the maximum value of the variance is equal to or less than the predetermined threshold, the determination unit 240 determines that the first radio device 100 is stationary.

[0062] Alternatively, the specific index may be the phase of the CSI. In this case, the multiple index values ​​indicate multiple phases corresponding to the multiple CSIs, respectively. One index value indicating the phase is expressed as in Equation 3.

[0063]

number

[0064] In this case, the determination unit 240 calculates the variance in the time direction based on the phase, and calculates the maximum value of the variance as the evaluation value. The determination unit 240 determines whether the maximum value of the variance exceeds a predetermined threshold, and if the maximum value of the variance exceeds the predetermined threshold, determines that the first radio device 100 is moving. If the maximum value of the variance is equal to or less than the predetermined threshold, the determination unit 240 determines that the first radio device 100 is stationary.

[0065] Alternatively, the specific index may be a correlation matrix of the CSI. In this case, the multiple index values ​​indicate multiple correlation matrices corresponding to the multiple CSIs, respectively. The correlation matrix is ​​calculated as follows:

[0066] First, the determination unit 240 vectorizes the complex transfer function matrix. The complex transfer function vector h vec (s, t) is expressed as in Equation 4.

[0067]

number

[0068] Then, the decision unit 240 calculates the complex transfer function vector h vec Based on (s, t), the correlation matrix R(s, t) is calculated. The correlation matrix R(s, t) is expressed as in Equation 5.

[0069]

number

[0070] Furthermore, the determination unit 240 extracts the off-diagonal terms from the correlation matrix R(s, t). The determination unit 240 extracts the correlation vector r vec Calculate (s,t) and the correlation vector r vec(s, t) is calculated as in Equation 6. Note that the correlation vector is not limited to an upper triangular matrix, and may be calculated by vectorizing a lower triangular matrix among the off-diagonal terms.

[0071]

number

[0072] The determination unit 240 determines the correlation vector r vec The variance in the time direction is calculated based on (s, t), and the maximum value of the variance is calculated as the evaluation value. The determination unit 240 determines whether the maximum value of the variance exceeds a predetermined threshold, and if the maximum value of the variance exceeds the predetermined threshold, determines that the first radio device 100 is moving. If the maximum value of the variance is equal to or less than the predetermined threshold, the determination unit 240 determines that the first radio device 100 is stationary.

[0073] Although determining section 240 calculates the variance in the time direction based on a plurality of index values, it may calculate a covariance instead of the variance. The covariance is calculated using any two of the CSI, the amplitude of the CSI, the phase of the CSI, and the correlation matrix, for example.

[0074] Furthermore, although the determination unit 240 calculates the maximum value of the variance based on the multiple index values ​​as the evaluation value, it may calculate at least one of the average value, median value, mode value, and minimum value, without being limited to the maximum value. The determination unit 240 may calculate at least one of the average value, median value, mode value, maximum value, and minimum value of the covariance based on the multiple index values ​​as the evaluation value. The determination unit 240 may also calculate a combination of two or more of the evaluation values ​​exemplified above as the evaluation value. When a combination of two or more evaluation values ​​is used, a representative value (average value, median value, mode value, maximum value, and minimum value) of the two or more evaluation values ​​may be calculated as the evaluation value for determining whether or not the mobile wireless device is stationary.

[0075] Furthermore, the determining unit 240 does not have to calculate an evaluation value for each component of the propagation characteristic H expressed three-dimensionally, but may calculate an evaluation value for a specific component.

[0076] When the determination unit 240 determines that the first radio device 100 is stationary, the sensing unit 250 senses the living body 300 in the target space 400 using the CSI included in the radio device information. The sensing unit 250 may use multiple CSIs to detect the position of the living body 300 in the target space 400, identify the posture of the living body 300, determine whether the living body 300 is present in the target space 400, identify the living body 300 based on CSI registered in advance for each individual living body 300, or identify the movement of the living body 300. In specifying the position of the living body 300 in the target space 400, the sensing unit 250 may calculate the total distance of the distance between the first radio device 100 and the living body 300 and the distance between the living body 300 and the second radio device 200, or may specify the direction (angle) of the living body 300 relative to the first radio device 100, or may specify the direction (angle) of the living body 300 relative to the second radio device 200.

[0077] [Operation] Next, a description will be given of the operation of the sensing device 200 according to Embodiment 1. Fig. 5 is a flowchart showing an example of a sensing method performed by the sensing device according to Embodiment 1.

[0078] First, the sensing device 200 acquires a plurality of pieces of time-series wireless device information (S11).

[0079] Next, the sensing device 200 calculates an evaluation value based on a plurality of time-series CSIs included in a plurality of pieces of time-series wireless device information (S12).

[0080] Next, the sensing device 200 determines whether the calculated evaluation value is greater than a predetermined threshold value (S13).

[0081] If the calculated evaluation value is greater than the predetermined threshold (Yes in S13), the sensing device 200 can determine that the first wireless device 100 is moving, and therefore ends the processing. In other words, if the calculated evaluation value is greater than the predetermined threshold, the sensing device 200 does not perform sensing.

[0082] If the calculated evaluation value is equal to or less than the predetermined threshold value (No in S13), the sensing device 200 can determine that the first wireless device 100 is stationary, and therefore performs sensing of the living body 300 (S14).

[0083] 5 may be periodically repeated or may be executed when a predetermined condition is met. The predetermined condition may be, for example, the arrival of a predetermined time or the reception of predetermined information.

[0084] [Effects, etc.] The sensing device 200 according to this embodiment includes an acquisition unit 230, a determination unit 240, and a sensing unit 250. The acquisition unit 230 acquires radio device information acquired by at least one of a first radio device 100 arranged in the target space 400 and capable of at least wireless transmission, and a second radio device 201 arranged in the target space 400 and capable of at least wireless reception. The determination unit 240 determines whether the first radio device 100 is stationary or not based on the radio device information. When the determination unit 240 determines that the first radio device 100 is stationary, the sensing unit 250 senses the living body 300 in the target space 400 using CSI (Channel State Information) included in the radio device information and received by the second radio device 201 from the first radio device 100.

[0085] According to this, when the mobile first radio device 100 is stationary, sensing within the target space 400 is performed using CSI, so there is no need to consider the influence of movement by the mobile first radio device 100, and therefore sensing of the living body 300 can be performed with high accuracy.

[0086] The sensing device 200 according to this embodiment further includes a storage unit 260. The storage unit 260 stores a plurality of pieces of radio device information acquired over a certain period of time. The determination unit 240 determines whether the first radio device 100 is stationary or not, using an evaluation value calculated from a plurality of index values ​​based on a plurality of CSIs included in the plurality of pieces of radio device information. Each of the plurality of index values ​​is an index value for a specific index of CSI to which the index value corresponds among the plurality of CSIs.

[0087] This allows a determination as to whether a mobile radio device is stationary or not based on multiple CSIs stored for a certain period of time, so that even a radio device that does not have a sensor that can detect movement can be determined as being stationary or not.

[0088] (Embodiment 2) In the second embodiment, a method of determining whether a wireless device is stationary and sensing a living body when the wireless device is stationary will be described for a SISO (Single-Input Single-Output) system in which both the transmitting antenna and the receiving antenna are one.

[0089] [composition] FIG. 6 is a diagram illustrating an example of the configuration of a sensing system according to the second embodiment.

[0090] The sensing system 1A includes a first radio device 100A and a sensing device 200A.

[0091] The first radio device 100A includes a transmitting antenna unit 110A, a transmitting unit 120, and a transmitting signal generating unit .

[0092] The transmitting antenna section 110A has one transmitting antenna element, which transmits a multicarrier signal (transmitting wave) generated by the transmitting section 120, which will be described later.

[0093] The transmission signal generating unit 130 generates a multicarrier signal in which a plurality of subcarrier signals are modulated. Specifically, the transmission signal generating unit 130 generates a plurality of subcarrier signals corresponding to a plurality of subcarriers in different frequency bands, and multiplexes the generated subcarrier signals to generate a multicarrier signal. In this embodiment, the transmission signal generating unit 130 generates an OFDM signal consisting of S subcarriers, which has high frequency band utilization efficiency, as a multicarrier signal. However, the transmission signal generating unit 130 is not limited to generating an OFDM signal in which the subcarriers are orthogonal, as long as the multicarrier signal is obtained by multicarrier modulation, and other multicarrier signals such as a simple FDM (Frequency Division Multiplexing) signal may be generated.

[0094] Furthermore, the signal generated by the transmission signal generating unit 130 may be used in common with the signal used for communication.

[0095] The transmitter 120 performs appropriate processing on the signal generated by the transmission signal generator 130 to generate a transmission wave. Examples of processing performed here include up-conversion, which converts the signal from an intermediate frequency (IF) frequency band to a radio frequency (RF) frequency band, and amplification, which amplifies the signal to an appropriate transmission level. The transmitter 120 outputs the processed multicarrier signal to the transmitting antenna unit 110A, causing the transmitting antenna unit 110A to transmit the multicarrier signal. As a result, the multicarrier signal is transmitted from one transmitting antenna element provided in the transmitting antenna unit 110A.

[0096] The sensing device 200A includes a receiving antenna unit 210A, a receiving unit 220, an acquiring unit 230, a determining unit 240, a sensing unit 250, and a storage unit 260. Of these, the receiving antenna unit 210A and the receiving unit 220 function as a second radio device 201A. In other words, in this embodiment, it can be said that the sensing device 200A includes the second radio device 201A.

[0097] The receiving antenna section 210A has one receiving antenna element, which receives a signal (received signal) that is transmitted from one transmitting antenna element and reflected by the living body 300.

[0098] The receiving unit 220 observes a received signal received by one receiving antenna element, which includes a reflected signal resulting from reflection or scattering of a multicarrier signal transmitted from one transmitting antenna element by the living organism 300, for a first period corresponding to a cycle derived from the activity of the living organism 300. The cycle derived from the activity of the living organism is a cycle derived from the living organism (biological fluctuation cycle) which is a time period equal to or longer than half the cycle of any one of the cycles of breathing, heartbeat, and body movement of the living organism 300.

[0099] The receiver 220 converts a high-frequency signal received by one receiving antenna element into a low-frequency signal that can be processed. The receiver 220 then demodulates the OFDM signal into S subcarrier signals. The S subcarrier signals are also called S IQ symbols. The S subcarrier signals are low-frequency signals.

[0100] The receiving unit 220 further calculates a plurality of complex transfer functions representing propagation characteristics between the transmitting antenna element and the receiving antenna element for each subcarrier from the S subcarrier signals obtained from the plurality of received signals observed over the first period. Note that the receiving unit 220 may constantly observe (or record) the received signals received by the receiving antenna unit 210A and acquire the S subcarrier signals continuously or periodically. In other words, the receiving unit 220 may acquire the S subcarrier signals at a plurality of different timings based on the received signals received at each timing.

[0101] The receiving unit 220 calculates a plurality of complex transfer functions representing the propagation characteristics between the transmitting antenna element and the receiving antenna element for each of the plurality of subcarriers to which the plurality of subcarrier signals respectively correspond.

[0102] In this embodiment, S subcarrier signals are used to calculate S sets of complex transfer functions representing propagation characteristics between each transmitting antenna element and each receiving antenna element for each of the S subcarrier signals. Note that the calculated complex transfer function matrix also includes reflected waves that do not pass through the living body 300, such as direct waves and reflected waves from fixed objects.

[0103] FIG. 7 is a diagram for explaining propagation characteristics at each timing.

[0104] As described above, the propagation characteristics H have a complex transfer function for one type of parameter for each subcarrier. That is, a different complex transfer function is calculated for each of a plurality of different subcarriers.

[0105] This figure shows an image of the propagation characteristic h(t) expressed by a combination of complex transfer functions when the number of receiving antenna elements is 1, the number of transmitting antenna elements is 1, and the number of subcarriers is 2, as shown in Figure 7. In this case, the propagation characteristic h(t) can be expressed as a combination of 1x1x2 blocks. One block represents one complex transfer function calculated for one receiving antenna element, one transmitting antenna element, and one specific subcarrier. In this way, the propagation characteristic H is expressed by one type of subcarrier parameter, and is therefore expressed as a one-dimensional vector. Furthermore, this propagation characteristic h(t) is calculated for each of multiple timings.

[0106] That is, in this embodiment, the receiving unit 220 calculates, from the S subcarrier signals transmitted from the transmitting unit 120, the propagation characteristic h(t) between one transmitting antenna element and one receiving antenna element during the observation time t, which is expressed as a complex transfer function vector as shown in Equation 7.

[0107]

number

[0108] The acquiring unit 230 acquires radio equipment information including the propagation characteristic h(t) calculated by the receiving unit 220. The propagation characteristic H is an example of CSI (Channel State Information). The acquiring unit 230 acquires a plurality of pieces of radio equipment information over a certain period of time. That is, the acquiring unit 230 acquires radio equipment information at each of a plurality of timings over the certain period of time. The plurality of pieces of radio equipment information acquired by the acquiring unit 230 may be stored in the storage unit 260. The plurality of pieces of radio equipment information includes a plurality of propagation characteristics H generated based on a plurality of received signals acquired at a plurality of consecutive timings.

[0109] The determination unit 240 determines whether the first radio device 100A is stationary based on the radio device information. Specifically, the determination unit 240 calculates an evaluation value based on multiple index values ​​based on multiple CSIs included in multiple pieces of radio device information stored in the storage unit 260. The evaluation value is an evaluation value for evaluating the variation in the multiple index values. For example, a larger evaluation value indicates a greater degree of variation in the multiple index values. Then, the determination unit 240 uses the calculated evaluation value to determine whether the first radio device 100A, which is a mobile radio device, is stationary. The multiple index values ​​respectively correspond to multiple CSIs. In other words, the multiple index values ​​respectively correspond to multiple received signals obtained at multiple different timings. The multiple index values ​​represent changes in the received signals in time series.

[0110] Here, each of the multiple index values ​​is an index value of a specific index of the CSI to which the index value corresponds among the multiple CSIs. The specific index may be, for example, the absolute value (i.e., amplitude) of the CSI. In this case, the multiple index values ​​indicate multiple absolute values ​​(amplitudes) corresponding to the multiple CSIs, respectively. One index value indicating the absolute value is expressed as shown in Equation 8.

[0111]

number

[0112] In this case, the determination unit 240 calculates the variance in the time direction based on the absolute value, and calculates the maximum value of the variance as the evaluation value. The determination unit 240 determines whether the maximum value of the variance exceeds a predetermined threshold, and if the maximum value of the variance exceeds the predetermined threshold, determines that the first radio device 100A is moving. If the maximum value of the variance is equal to or less than the predetermined threshold, the determination unit 240 determines that the first radio device 100A is stationary.

[0113] Alternatively, the specific index may be the phase of the CSI. In this case, the multiple index values ​​indicate multiple phases corresponding to the multiple CSIs, respectively. One index value indicating the phase is expressed as in Equation 9.

[0114]

number

[0115] In this case, the determination unit 240 calculates the variance in the time direction based on the phase, and calculates the maximum value of the variance as the evaluation value. The determination unit 240 determines whether the maximum value of the variance exceeds a predetermined threshold, and if the maximum value of the variance exceeds the predetermined threshold, determines that the first radio device 100A is moving. If the maximum value of the variance is equal to or less than the predetermined threshold, the determination unit 240 determines that the first radio device 100A is stationary.

[0116] Alternatively, the specific index may be a correlation matrix of the CSI. In this case, the multiple index values ​​indicate multiple correlation matrices corresponding to the multiple CSIs, respectively. The correlation matrix is ​​calculated as follows:

[0117] The determining unit 240 calculates the correlation matrix R(t) based on the complex transfer function vector h(t). The correlation matrix R(t) is expressed as in Equation 10.

[0118]

number

[0119] Furthermore, the determination unit 240 extracts the off-diagonal terms from the correlation matrix R(t). The determination unit 240 extracts the correlation vector r vec (t) is calculated. The correlation vector is not limited to an upper triangular matrix, and may be calculated by vectorizing a lower triangular matrix among the off-diagonal terms.

[0120] The determination unit 240 determines the correlation vector r vec The first radio device 100A calculates the variance in the time direction based on (t) and calculates the maximum value of the variance as the evaluation value. The determination unit 240 determines whether the maximum value of the variance exceeds a predetermined threshold, and if the maximum value of the variance exceeds the predetermined threshold, determines that the first radio device 100A is moving. If the maximum value of the variance is equal to or less than the predetermined threshold, the determination unit 240 determines that the first radio device 100A is stationary.

[0121] Although determining section 240 calculates the variance in the time direction based on a plurality of index values, it may calculate a covariance instead of the variance. The covariance is calculated using any two of the CSI, the amplitude of the CSI, the phase of the CSI, and the correlation matrix, for example.

[0122] Furthermore, although the determination unit 240 calculates the maximum value of the variance based on the multiple index values ​​as the evaluation value, it may calculate at least one of the average value, median value, mode value, and minimum value, without being limited to the maximum value. The determination unit 240 may calculate at least one of the average value, median value, mode value, maximum value, and minimum value of the covariance based on the multiple index values ​​as the evaluation value. The determination unit 240 may calculate at least one of the average value, median value, mode value, maximum value, and minimum value of the multiple index values ​​as the evaluation value. The determination unit 240 may also calculate a combination of two or more of the evaluation values ​​exemplified above as the evaluation value. When a combination of two or more evaluation values ​​is used, a representative value (average value, median value, mode value, maximum value, and minimum value) of the two or more evaluation values ​​may be calculated as the evaluation value for determining whether the mobile wireless device is stationary or not.

[0123] Furthermore, the determining unit 240 does not have to calculate an evaluation value for each component of the propagation characteristic H expressed three-dimensionally, but may calculate an evaluation value for a specific component.

[0124] When the determination unit 240 determines that the first radio device 100A is stationary, the sensing unit 250 uses the CSI included in the radio device information to sense the living body 300 in the target space 400. The sensing unit 250 may use multiple CSIs to detect the position of the living body 300 in the target space 400, or may specify the posture of the living body 300, or may identify the living body 300 based on the CSI registered in advance for each individual living body 300, or may specify the movement of the living body 300.

[0125] The operation of the sensing device 200A can be explained in the same way as the sensing device 200, and therefore the explanation will be omitted.

[0126] (Variation 1) In the above-described embodiment, the sensing devices 200 and 200A may be configured separately from the second radio devices 201 and 201A. In this case, the sensing devices 200 and 200A may acquire radio device information including the propagation characteristic H calculated based on the signal received by the second radio devices 201 and 201A by communicating with the second radio devices 201 and 201A.

[0127] (Variation 2) In the above embodiment, the second radio devices 201, 201A have been described as fixed routers, but they may be configured as mobile devices similar to the first radio devices 100, 100A. Even in this case, the sensing devices 200, 200A can determine whether both the first radio devices 100, 100A and the second radio devices 201, 201A are stationary by determining whether the evaluation value is greater than a predetermined threshold, as described in the embodiment. In other words, if the evaluation value is greater than the predetermined threshold, it is determined that either the first radio devices 100, 100A or the second radio devices 201, 201A is moving, and if the evaluation value is equal to or less than the predetermined threshold, it is determined that both the first radio devices 100, 100A and the second radio devices 201, 201A are stationary.

[0128] (Variation 3) In the above embodiment, it is determined whether both the first radio devices 100, 100A and the second radio devices 201, 201A are stationary based on the CSI. However, this is not limiting. For example, consider a case where the first radio devices 100, 100A are mobile and the second radio devices 201, 201A are fixed. In this case, the first radio devices 100, 100A may have a sensor for detecting the movement of the first radio devices 100, 100A, and the sensing device 200 may acquire the detection result of the sensor from the first radio devices 100, 100A as radio device information. The sensing device 200 may determine whether the first radio devices 100, 100A are moving or stationary based on the detection result. The sensor may be, for example, an acceleration sensor, an angular velocity sensor, or a GPS (Global Positioning System) sensor. Note that if the second radio devices 201, 201A are also mobile, the second radio devices 201, 201A may also have sensors for detecting movement like the first radio devices 100, 100A, and the sensing device 200 may determine whether the second radio devices 201, 201A are moving or stationary based on the detection results of the sensors. This also applies to the case where the first radio devices 100, 100A are fixed and the second radio devices 201, 201A are mobile. In this way, the sensing device 200 may determine whether both the first radio devices 100, 100A and the second radio devices 201, 201A are stationary based on the detection results of the sensors for detecting movement obtained from all mobile radio devices.

[0129] According to this, whether or not the mobile radio device is stationary is determined based on sensing information obtained by at least one of an acceleration sensor, an angular velocity sensor, and a GPS sensor, so that whether or not the mobile radio device is stationary can be determined with high accuracy.

[0130] (Variation 4) In the above embodiment, the mobile wireless device may hold an identifier for identifying the mobile wireless device, and the identifier may be included in the transmission signal and transmitted, thereby enabling the sensing device 200 to identify the mobile wireless device.

[0131] (Variation 5) In the above embodiment, the sensing devices 200, 200A including the first radio devices 100, 100A and the second radio devices 201, 201A are configured as separate entities, but the present invention is not limited to this and they may be configured as an integrated device. Even in this case, the sensing devices 200, 200A can determine whether the integrated first radio devices 100, 100A and second radio devices 201, 201A are stationary using a method similar to that of the above embodiment.

[0132] (Variation 6) In the above-mentioned first embodiment, the complex transfer function matrix is ​​vectorized, but it is not necessary to vectorize it. Also, in the above-mentioned first embodiment, a matrix having elements corresponding to each transmitting antenna element and each receiving antenna element for each subcarrier is vectorized, but a three-dimensional matrix of the transmitting antenna element direction, the receiving antenna element direction, and the subcarrier direction may be vectorized.

[0133] (others) FIG. 8 is a diagram showing the results of an experiment on an evaluation value for evaluating whether a wireless device is stationary based on CSI.

[0134] 8 is a diagram showing the IQ waveform, amplitude, unwrapped phase, amplitude variance, unwrapped phase variance, and correlation matrix variance obtained from CSI in a stationary state, a state in which the mobile radio device is moving slightly, and a state in which the mobile radio device is moving significantly. As shown in FIG. 8, it can be seen that in a stationary state, the change is small, and the change becomes larger as the movement becomes larger. In this way, it can be seen that by calculating the amplitude, phase, correlation matrix, and their variances as evaluation values, it is possible to determine whether the mobile radio device is moving or stationary.

[0135] In each of the above embodiments, each component may be configured with dedicated hardware, or may be realized by executing a software program suitable for each component. Each component may also be realized by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory.

[0136] Furthermore, the present disclosure can be realized not only as a sensing device having such characteristic components, but also as a sensing method in which the characteristic components included in the sensing device are used as steps. It can also be realized as a computer program that causes a computer to execute each of the characteristic steps included in such a method. It goes without saying that such a computer program can be distributed on a computer-readable non-transitory recording medium such as a CD-ROM or via a communication network such as the Internet. [Industrial Applicability]

[0137] The present disclosure can be used in sensing devices and sensing methods that estimate the distance and position of a living body using wireless signals, and in particular in measuring devices that measure the distance and position of a living body, including between a living body and a machine, home appliances that perform control according to the distance and position of a living body, and monitoring devices that detect the intrusion of a living body. [Explanation of symbols]

[0138] 1. 1A Sensing System 100, 100A 1st radio 110, 110A Transmitting antenna section 120 Transmitter 130 Transmission signal generation unit 200, 200A sensing device 201, 201A 2nd radio 210, 210A Receiving antenna section 220 Receiving unit 230 Acquisition Department 240 Judgment section 250 Sensing Unit 260 Storage section 300 Living organisms 400 Target Space

Claims

1. an acquisition unit that acquires radio device information acquired by at least one of a first radio device that is arranged in the target space and is capable of at least wireless transmission, and a second radio device that is arranged in the target space and is capable of at least wireless reception; a determination unit that determines whether a mobile wireless device of the first wireless device and the second wireless device is stationary based on the wireless device information; a sensing unit that senses a living body in the target space by using CSI (Channel State Information) included in the radio device information when the determination unit determines that the mobile radio device is stationary and that the CSI is received by the second radio device from the first radio device. Sensing device.

2. the wireless device information further includes sensing information obtained by at least one sensor of an acceleration sensor, an angular velocity sensor, and a GPS (Global Positioning System) sensor provided in the mobile wireless device; The determination unit determines whether the mobile wireless device is stationary based on the sensing information. The sensing device according to claim 1 .

3. moreover, a storage unit that stores a plurality of pieces of radio device information acquired over a certain period of time; the determination unit determines whether the mobile wireless device is stationary using an evaluation value calculated from a plurality of indicator values ​​based on a plurality of CSIs included in the plurality of pieces of wireless device information; Each of the plurality of index values ​​is an index value for a specific index of the CSI to which the index value corresponds among the plurality of CSIs. The sensing device according to claim 1 .

4. The specific indicator includes the absolute value (amplitude) of the CSI. The sensing device according to claim 3 .

5. The specific indicator includes a phase of the CSI. The sensing device according to claim 3 .

6. The specific indicator includes a correlation matrix of CSI. The sensing device according to claim 3 .

7. The evaluation value includes a variance or a covariance of the plurality of index values. The sensing device according to any one of claims 3 to 6.

8. The evaluation value includes at least one of the mean, median, mode, maximum, and minimum of the plurality of index values ​​or the variance or covariance of the plurality of index values. The sensing device according to any one of claims 3 to 6.

9. A sensing method performed by a sensing device, comprising: acquiring radio device information acquired by at least one of a first radio device arranged in the target space and capable of at least wireless transmission and a second radio device arranged in the target space and capable of at least wireless reception; determining whether a mobile wireless device of the first wireless device and the second wireless device is stationary based on the wireless device information; When it is determined in the determination that the mobile radio device is stationary, sensing of a living body in the target space is performed using CSI (Channel State Information) included in the radio device information, which is CSI received by the second radio device from the first radio device. Sensing method.

10. A program for causing a computer to execute the sensing method according to claim 9.

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