Sensing device, sensing method, and program
The sensing device uses CSI from stationary wireless devices to accurately detect living organisms by determining radio stationarity, addressing the inaccuracy issues in conventional sensing methods due to device movement.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
- Filing Date
- 2024-03-28
- Publication Date
- 2026-06-19
Smart Images
Figure 0007876140000011 
Figure 0007876140000012 
Figure 0007876140000013
Abstract
Description
Technical Field
[0001] The present disclosure relates to a sensing device, a sensing method, and a program for accurately sensing a living body.
Background Art
[0002] As a method for knowing the position of a person or the like, a method using a radio signal has been studied. For example, Patent Document 1 discloses a technique for estimating the position and state of a person to be detected by analyzing a component including a Doppler shift using differential calculation.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] With the conventional method, it is difficult to sense a living body with higher accuracy.
[0005] The present disclosure has been made in view of the above circumstances, and provides a sensing device and the like that can sense a living body with higher accuracy.
Means for Solving the Problems
[0006] A sensing device according to an aspect of the present disclosure includes a first radio device disposed in a target space and capable of at least wireless transmission, and a second radio device disposed in the target space and capable of at least wireless reception At least one of the first radio and the second radio is a portable radio, and the first radio and the second radio an acquisition unit that acquires radio device information acquired by at least one of the radio devices, A storage unit that stores multiple radio equipment information acquired over a certain period of time, and an evaluation value calculated from multiple index values based on multiple CSIs (Channel State Information) included in the multiple radio equipment information stored in the storage unit, or (ii) an evaluation value calculated from the index value of a specific index of the CSI corresponding to the multiple index values based on the multiple CSIs stored in the storage unit, a determination unit that determines whether a movable radio device is stationary, and when the determination unit determines that the movable radio device is stationary, CS included in the radio device information IAnd, from the aforementioned first radio Sent The second wireless device uses the CSI received to sense living organisms in the target space, and if the determination unit determines that the movable wireless device is moving, The living organism in the aforementioned target space A sensing unit that does not perform the aforementioned sensing, Equipped with .
[0007] Furthermore, a sensing method according to one aspect of the present disclosure is a sensing method performed by a sensing device, wherein wireless device information is acquired by at least one of a first wireless device arranged in a target space and capable of wireless transmission, and a second wireless device arranged in the target space and capable of wireless reception, At least one of the first and second radios is a portable radio, which stores a plurality of radio information acquired over a certain period of time, and uses (i) an evaluation value calculated from a plurality of index values based on a plurality of CSIs (Channel State Information) contained in the stored plurality of radio information, or (ii) an evaluation value calculated from the index value of a specific index of the CSI corresponding to the plurality of index values based on the stored plurality of CSIs, It is determined whether the portable radio is stationary, and if it is determined in the determination that the portable radio is stationary, the CS included in the radio information is determined. I And, from the aforementioned first radio Sent The second radio uses the CSI received to sense living organisms in the target space, and if the determination determines that the movable radio is moving, The living organism in the aforementioned target space The aforementioned sensing is performed. do not have .
[0008] These general or specific embodiments may be implemented as a system, integrated circuit, computer program, or recording medium such as a computer-readable CD-ROM, or as any combination of apparatus, system, method, integrated circuit, computer program, and recording medium. [Effects of the Invention]
[0009] The sensing device described herein enables more accurate sensing of living organisms. [Brief explanation of the drawing]
[0010] [Figure 1] Figure 1 is a diagram illustrating the overview of the sensing system in Embodiment 1. [Figure 2]FIG. 2 is a diagram showing an example of the configuration of the sensing system in Embodiment 1. [Figure 3] FIG. 3 is a diagram for explaining the relationship between the transmission signal, the channel, and the reception signal. [Figure 4] FIG. 4 is a diagram for explaining the propagation characteristics at each timing. [Figure 5] FIG. 5 is a flowchart showing an example of the sensing method by the sensing device according to Embodiment 1. [Figure 6] FIG. 6 is a diagram showing an example of the configuration of the sensing system in Embodiment 2. [Figure 7] FIG. 7 is a diagram for explaining the propagation characteristics at each timing. [Figure 8] FIG. 8 is a diagram showing the experimental results of the evaluation value for evaluating whether the wireless device is stationary based on CSI.
MODE FOR CARRYING OUT THE INVENTION
[0011] (Knowledge on which the present disclosure is based) As a method for sensing a living body, a method using a wireless signal has been studied.
[0012] In the prior art such as Patent Document 1, the transmission device that transmits a wireless signal and the reception device that receives the wireless signal are fixed, and it is not considered that at least one of the transmission device and the reception device moves. When at least one of the transmission device and the reception device moves and the position changes, the wireless signal is affected by the change in the position, so it is difficult to accurately sense the living body.
[0013] Therefore, the present inventors have found a sensing device and the like that can accurately sense a living body.
[0014] A sensing device according to a first aspect of this 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 wireless transmission, and a second radio device arranged in the target space and capable of wireless reception; a determination unit that determines whether the movable radio device among the first and second radio devices is stationary based on the radio device information; and a sensing unit that, if the determination unit determines that the movable radio device is stationary, uses the CSI (Channel State Information) included in the radio device information, which the second radio device has received from the first radio device, to sense a living organism in the target space.
[0015] According to this method, since sensing within the target space is performed using CSI when the mobile radio is stationary, there is no need to consider the effects of movement by the mobile radio, thus enabling accurate sensing of living organisms.
[0016] A sensing device according to a second aspect of the present disclosure is a sensing device according to a first aspect, wherein the radio device information further includes sensing information obtained by at least one of the following sensors provided by the mobile radio device: an acceleration sensor, an angular velocity sensor, and a GPS (Global Positioning System) sensor, and the determination unit determines whether or not the mobile radio device is stationary based on the sensing information.
[0017] According to this, by determining whether a mobile radio is stationary or not based on sensing information obtained from at least one of the following sensors—an acceleration sensor, an angular velocity sensor, and a GPS sensor—it is possible to accurately determine whether a mobile radio is stationary or not.
[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 storage unit for storing a plurality of radio device information acquired over a certain period of time, wherein the determination unit determines whether the movable radio device 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 radio device information, and each of the plurality of index values is an index value in a specific index of the CSI to which the index value corresponds among the plurality of CSIs.
[0019] According to this method, by determining whether a mobile radio is stationary or not based on multiple CSIs stored for a certain period of time, it is possible to determine whether a radio is stationary or not even if it does not have a sensor that can detect movement.
[0020] A sensing device according to a fourth aspect of this disclosure is a sensing device according to a third aspect, wherein the specified index includes the absolute value (amplitude) of the CSI.
[0021] A sensing device according to a fifth aspect of this disclosure is a sensing device according to a third or fourth aspect, wherein the specific index includes the phase of the CSI.
[0022] A sensing device according to the sixth aspect of this disclosure is a sensing device according to any one aspect of the third to fifth aspects, wherein the specific index includes a correlation matrix of CSI.
[0023] A sensing device according to the seventh aspect of this disclosure is a sensing device according to any one aspect of the third to sixth aspects, wherein the evaluation value includes the variance or covariance of the plurality of index values.
[0024] A sensing device according to the eighth aspect of this disclosure is a sensing device according to any one aspect 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 this disclosure is a sensing method performed by a sensing device, which acquires radio device information obtained by at least one of a first radio device, which is located in a target space and capable of wireless transmission, and a second radio device, which is located in the target space and capable of wireless reception; determines whether the movable radio device among the first and second radio devices is stationary based on the radio device information; and if it is determined in the determination that the movable radio device is stationary, it performs sensing of a living organism in the target space using the CSI (Channel State Information) included in the radio device information, which the second radio device received from the first radio device.
[0026] According to this method, since sensing within the target space is performed using CSI when the mobile radio is stationary, there is no need to consider the effects of movement by the mobile radio, thus enabling accurate sensing of living organisms.
[0027] The program relating to the tenth aspect of this disclosure is a program for causing a computer to execute the sensing method relating to the ninth aspect.
[0028] Furthermore, this disclosure can be implemented not only as a device, but also as an integrated circuit equipped with processing means of such a device, as a method in which the processing means constituting the device are used as steps, as a program that causes a computer to execute those steps, or as information, data, or signals representing that 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] The embodiments of this disclosure will be described in detail below with reference to the drawings. The embodiments described below are all preferred examples of the disclosure. The numerical values, shapes, materials, components, arrangement and connection configurations of components, steps, and the order of steps shown in the following embodiments are examples only and are not intended to limit the disclosure. Furthermore, components in the following embodiments that are not described in the independent claims representing the highest-level concepts of this disclosure will be described as any component constituting a more preferred configuration. In this specification and in the drawings, components having substantially the same functional configuration are denoted by the same reference numerals to avoid redundant explanation.
[0030] (Embodiment 1) Embodiment 1 describes a method for determining the stationary state of a wireless device and sensing a living organism in the case of a MIMO (Multiple-Input Multiple-Output) system where both the transmitting and receiving antennas are multiple. The method is also applicable to SIMO (Single-Input Multiple-Output) and MISO (Multiple-Input Single-Output) systems where either the transmitting or receiving antenna is multiple.
[0031] [composition] Figure 1 is a diagram illustrating the overview of the sensing system in Embodiment 1.
[0032] Specifically, Figure 1 shows a first wireless device 100, a sensing device 200, and a living organism 300. For example, sensing system 1 comprises the first wireless device 100 and the sensing device 200. The first wireless device 100 is a wireless device that is placed in the target space 400 and is capable of wireless transmission. The target space 400 is a space in which the living organism 300 can be sensed by the first wireless device 100 and the sensing device 200, and is the space that is the target of said 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 wireless signals transmitted from the first wireless device 100. 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] The sensing system 1 has a first radio 100 that transmits a radio signal to the sensing device 200. When the first radio 100 transmits the radio signal, it 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 the living organism 300 within the target space 400. The sensing device 200 receives the radio waves, including those reflected by the living organism 300, and performs sensing of the living organism 300 based on the received radio waves. Sensing of 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 or not the living organism 300 is present in the target space 400, identifying the movement of the living organism 300, and identifying the posture of the living organism 300. In determining the position of the living organism 300 in the target space 400, the sum of the distance between the first radio 100 and the living organism 300 and the distance between the living organism 300 and the second radio 200 may be calculated, or the direction (angle) of the living organism 300 relative to the first radio 100 may be determined, or the direction (angle) of the living organism 300 relative to the second radio 200 may be determined.
[0034] Furthermore, for sensing the biological organism 300, methods such as MUSIC (Multiple Signal Classification) method, beamformer method, and Capon method, or other conventionally known methods may be used, and sensors that realize these functions may be provided in the first wireless device 100 or sensing device 200.
[0035] Figure 2 shows an example of the configuration of the sensing system in Embodiment 1.
[0036] The sensing system 1 comprises a first radio 100 and a sensing device 200.
[0037] The first radio 100 comprises a transmitting antenna unit 110, a transmitting unit 120, and a transmitting signal generation unit 130.
[0038] The transmitting antenna unit 110 has M transmitting antenna elements, where M is a natural number greater than or equal to 1. The M transmitting antenna elements transmit a multi-carrier signal (transmitted wave) generated by the transmitting unit 120, which will be described later.
[0039] The transmission signal generation unit 130 generates a multicarrier signal in which multiple subcarrier signals are modulated. Specifically, the transmission signal generation unit 130 generates multiple subcarrier signals corresponding to multiple subcarriers in different frequency bands, and generates a multicarrier signal by multiplexing the generated multiple subcarrier signals. In this embodiment, the transmission signal generation unit 130 will be described as generating an OFDM (Orthogonal Frequency Division Multiplexing) signal consisting of S subcarriers, which has high frequency band utilization efficiency, as the multicarrier signal. However, as long as the multicarrier signal obtained by multicarrier modulation is not limited to generating an OFDM signal in which each subcarrier is orthogonal, other multicarrier signals such as a simple FDM (Frequency Division Multiplexing) signal may also be generated.
[0040] Furthermore, the signals generated by the transmission signal generation unit 130 may be shared with signals used for communication.
[0041] The transmitting unit 120 processes the signal generated by the transmitting signal generation unit 130 to generate a transmission wave. This processing includes, for example, upconversion (converting the signal from the IF (Intermediate Frequency) band to the RF (Radio Frequency) band) and amplification (amplifying the signal to an appropriate transmission level). The transmitting unit 120 outputs the processed multi-carrier signal to the transmitting antenna unit 110, causing the antenna unit 110 to transmit the signal. As a result, the multi-carrier signal is transmitted from the M transmitting antenna elements of the transmitting antenna unit 110.
[0042] The sensing device 200 comprises a receiving antenna unit 210, a receiving unit 220, an acquisition unit 230, a determination 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 201. In other words, in this embodiment, the sensing device 200 can be said to have a second radio 201.
[0043] The receiving antenna unit 210 has N receiving antenna elements, where N is a natural number greater than or equal to 1. Note that if one of M and N is 1, the other is 2 or greater. The N receiving antenna elements receive signals (received signals) transmitted from the M transmitting antenna elements and reflected by the living organism 300.
[0044] The receiving unit 220 observes the received signal, which is received by N receiving antenna elements and includes reflected signals resulting from the reflection or scattering of multicarrier signals transmitted from M transmitting antenna elements by the living organism 300, for a first period corresponding to a period derived from the activity of the living organism 300. The period derived from the activity of the living organism is a period derived from the living organism (living fluctuation period) that is half a period or longer of any of the periods of respiration, heartbeat, or body movement of the living organism 300. The received signal may include information about the transmitted signal that was the source of the received signal, which was transmitted by the first radio 100. Note that the information about the transmitted signal that was the source of the received signal does not have to be included in the received signal, and may be transmitted from the first radio 100 to the sensing device 200 by other 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. These S subcarrier signals are also called S IQ symbols. These S subcarrier signals are low-frequency signals.
[0046] The receiving unit 220 further calculates multiple complex transfer functions representing the propagation characteristics between the transmitting antenna element and the receiving antenna element for each subcarrier, based on the S subcarrier signals obtained from multiple received signals observed over the first period. The receiving unit 220 may continuously observe (or record) the received signals received by the receiving antenna unit 210 and acquire S subcarrier signals continuously or periodically. In other words, the receiving unit 220 may acquire S subcarrier signals at multiple different timings, based on the received signals received at each timing.
[0047] The receiving unit 220 uses multiple received signals observed over the first period to calculate multiple complex transfer functions representing the propagation characteristics between the transmitting antenna elements and the receiving antenna elements for each of the N × M combinations, which are combinations of each of the M transmitting antenna elements and each of the N receiving antenna elements. These complex transfer functions are calculated for each of the multiple subcarriers that each of the multiple subcarrier signals corresponds to. Note that the N × M combinations are all possible combinations when the 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 an N×M×S complex transfer function for each of the S subcarrier signals, representing the propagation characteristics between each transmitting antenna element and each receiving antenna element. The calculated complex transfer function matrix includes reflected waves that do not pass through the biological 300, such as direct waves and reflected waves originating from fixed objects.
[0049] Figure 3 is a diagram illustrating the relationship between the transmitted signal, channel, and received signal.
[0050] The transmitted signal X sent from the transmitting antenna unit 110 propagates through the target space 400 and is received by the receiving antenna unit 210, where it is acquired as the received signal Y. The received signal Y received by the receiving antenna unit 210 is a signal that has changed as the transmitted signal X propagates through the target space 400. Therefore, the received signal Y can be considered to be equal to the signal obtained by multiplying the propagation characteristic H of space 400 by the transmitted signal X. The propagation characteristic H is represented by the N×M×S complex transfer function described above.
[0051] Figure 4 is a diagram illustrating the propagation characteristics at each timing.
[0052] As described above, the propagation characteristic H has a complex transfer function for each combination of three types of parameters: each receiving antenna element, each transmitting antenna element, and each subcarrier. In other words, a different complex transfer function is calculated for each of several different receiving antenna elements, a different complex transfer function is calculated for each of several different transmitting antenna elements, and a different complex transfer function is calculated for each of several different subcarriers.
[0053] Figure 4 shows an image of the propagation characteristics H, represented by a combination of complex transfer functions, for the case where the number of receiving antenna elements is 3, the number of transmitting antenna elements is 4, and the number of subcarriers is 2. In this case, the propagation characteristics H can be represented as a combination of 3 × 4 × 2 blocks. Each block represents a single complex transfer function calculated for a specific receiving antenna element, a specific transmitting antenna element, and a specific subcarrier. Thus, since the propagation characteristics H are represented as a combination of three types of parameters—receiving antenna elements, transmitting antenna elements, and subcarriers—they can be represented three-dimensionally. Furthermore, this three-dimensionally represented propagation characteristics H are calculated for each of multiple timings.
[0054] In addition, the subcarrier and transmitting antenna element may be fixed, and the multiple complex transfer functions of different receiving antenna elements may be expressed as multiple complex transfer functions different in the direction of the receiving antenna element. Similarly, the subcarrier and receiving antenna element may be fixed, and the multiple complex transfer functions of different transmitting antenna elements may be expressed as multiple complex transfer functions different in the direction of the transmitting antenna element. Similarly, the receiving antenna element and transmitting antenna element may be fixed, and the multiple complex transfer functions of different subcarriers may be expressed as multiple complex transfer functions different in the direction of the subcarrier. Thus, in the propagation characteristics H expressed in three dimensions, the directions of each dimension may be expressed using names related to three types of parameters as the direction of the receiving antenna element, the direction of the transmitting antenna element, and the direction of the subcarrier.
[0055] For example, if we assign the rows of the matrix representing the propagation characteristics H to the receiving antenna elements of the third order and the columns to the transmitting antenna elements, then different propagation characteristics H will be calculated for each subcarrier and for each timing of receiving the signal. In other words, in this embodiment, the receiving unit 220 determines that the propagation characteristics H(s,t) between the M transmitting antenna elements and the N receiving antenna elements for the s-th subcarrier during the observation time t, based on S subcarrier signals transmitted from the receiving unit 220, are expressed in the complex transfer function matrix as shown in Equation 1.
[0056]
number
[0057] The acquisition unit 230 acquires radio equipment information, including propagation characteristics H calculated by the receiving unit 220. Propagation characteristics H is an example of CSI (Channel State Information). The acquisition unit 230 acquires multiple radio equipment information over a certain period of time. That is, the acquisition unit 230 acquires radio equipment information at each of several timings over a certain period of time. The multiple radio equipment information acquired by the acquisition unit 230 may be stored in the storage unit 260. The multiple radio equipment information includes multiple propagation characteristics H generated based on multiple received signals acquired at multiple consecutive timings.
[0058] The determination unit 240 determines whether the first radio 100 is stationary or not based on the radio information. Specifically, the determination unit 240 calculates an evaluation value based on multiple index values derived from multiple CSIs included in the multiple radio information stored in the storage unit 260. The evaluation value is an evaluation value used to evaluate the variability of the multiple index values. For example, a larger evaluation value indicates a greater degree of variability in the multiple index values. Then, the determination unit 240 uses the calculated evaluation value to determine whether the first radio 100, which is a mobile radio, is stationary or not. Each of the multiple index values corresponds to multiple CSIs. In other words, each of the multiple index values corresponds to multiple received signals obtained at multiple different timings. The multiple index values represent the changes in the received signal over time.
[0059] Here, each of the multiple index values is an index value for a specific index of the CSI to which that index value corresponds. The specific index may be, for example, the absolute value (i.e., amplitude) of the CSI. In this case, the multiple index values represent multiple absolute values (amplitudes) corresponding to multiple CSIs. A single index value that represents an absolute value is expressed as shown in Equation 2.
[0060]
number
[0061] In this case, the determination unit 240 calculates the time variance 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 determines that the first radio 100 is moving if the maximum value of the variance exceeds the predetermined threshold. The determination unit 240 determines that the first radio 100 is stationary if the maximum value of the variance is less than or equal to the predetermined threshold.
[0062] Furthermore, a specific index may be a phase of the CSI. In this case, multiple index values represent multiple phases corresponding to multiple CSIs. A single index value representing a phase is expressed as shown in Equation 3.
[0063]
number
[0064] In this case, the determination unit 240 calculates the time variance 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 determines that the first radio 100 is moving if the maximum value of the variance exceeds the predetermined threshold. The determination unit 240 determines that the first radio 100 is stationary if the maximum value of the variance is less than or equal to the predetermined threshold.
[0065] Furthermore, a specific indicator may be a correlation matrix of CSIs. In this case, multiple indicator values represent multiple correlation matrices corresponding to multiple CSIs. The correlation matrix is calculated as follows.
[0066] The determination unit 240 first vectorizes the complex transfer function matrix. The complex transfer function vector h obtained by vectorization vec (s,t) can be expressed as shown in Equation 4.
[0067]
number
[0068] Then, the determination unit 240 determines 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 shown in Equation 5.
[0069]
number
[0070] Furthermore, the determination unit 240 extracts off-diagonal terms from the correlation matrix R(s,t). The determination unit 240 then vectorizes the upper triangular matrix from the off-diagonal terms into a correlation vector r vec Calculate (s,t). Correlation vector r vec(s,t) is calculated as shown in Equation 6. Note that the correlation vector is not limited to upper triangular matrices; it may also be calculated by vectorizing the lower triangular matrices among the off-diagonal terms.
[0071]
number
[0072] The determination unit 240 determines the correlation vector r vec The time-direction variance 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, it determines that the first radio 100 is moving. If the maximum value of the variance is less than or equal to the predetermined threshold, the determination unit 240 determines that the first radio 100 is stationary.
[0073] Although the determination unit 240 is said to calculate the time-direction variance based on multiple index values, it may also calculate covariance instead of variance. Covariance is calculated using, for example, any two of the following: CSI, CSI amplitude, CSI phase, and correlation matrix.
[0074] Furthermore, although the determination unit 240 calculates the maximum value of the variance based on multiple indicator values as an evaluation value, it may calculate at least one of the mean, median, mode, and minimum values, rather than being limited to the maximum value. The determination unit 240 may calculate at least one of the mean, median, mode, maximum, and minimum values of the covariance based on multiple indicator values as an evaluation value. In addition, the determination unit 240 may calculate two or more combinations of the multiple evaluation values exemplified above as evaluation values. When using two or more combinations of evaluation values, representative values (mean, median, mode, maximum, and minimum) of the two or more evaluation values may be calculated as evaluation values for determining whether a mobile radio is stationary or not.
[0075] Furthermore, the determination unit 240 does not need to calculate an evaluation value for each component of the propagation characteristic H represented in three dimensions, and may calculate an evaluation value for a specific component.
[0076] If the determination unit 240 determines that the first radio 100 is stationary, the sensing unit 250 uses the CSI included in the radio information to sense the living organism 300 in the target space 400. The sensing unit 250 may use multiple CSIs to detect the position of the living organism 300 in the target space 400, identify the posture of the living organism 300, determine whether or not the living organism 300 is present in the target space 400, identify the living organism 300 based on a CSI registered in advance for each individual living organism 300, or identify the movement of the living organism 300. In addition, when determining the position of the living organism 300 in the target space 400, the sensing unit 250 may calculate the sum of the distance between the first radio 100 and the living organism 300 and the distance between the living organism 300 and the second radio 200, or it may determine the direction (angle) of the living organism 300 relative to the first radio 100, or it may determine the direction (angle) of the living organism 300 relative to the second radio 200.
[0077] [Operation] Next, the operation of the sensing device 200 according to Embodiment 1 will be described. Figure 5 is a flowchart showing an example of a sensing method using the sensing device according to Embodiment 1.
[0078] First, the sensing device 200 acquires time-series information on multiple radio devices (S11).
[0079] Next, the sensing device 200 calculates an evaluation value based on multiple time-series CSIs included in multiple time-series radio information (S12).
[0080] Next, the sensing device 200 determines whether the calculated evaluation value is greater than a predetermined threshold (S13).
[0081] If the calculated evaluation value is greater than a predetermined threshold (Yes in S13), the sensing device 200 can determine that the first radio 100 is moving and terminates processing. In other words, the sensing device 200 does not perform sensing if the calculated evaluation value is greater than a predetermined threshold.
[0082] If the calculated evaluation value is below a predetermined threshold (No in S13), the sensing device 200 can determine that the first radio 100 is stationary, and therefore performs sensing of the living organism 300 (S14).
[0083] The sensing device 200 may periodically repeat steps S11 to S14 shown in Figure 5, or it may execute them when predetermined conditions are met. These predetermined conditions include, 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 comprises an acquisition unit 230, a determination unit 240, and a sensing unit 250. The acquisition unit 230 acquires radio information acquired by at least one of the radios, which is a first radio 100 located in the target space 400 and capable of wireless transmission, and a second radio 201 located in the target space 400 and capable of wireless reception. The determination unit 240 determines whether the first radio 100 is stationary based on the radio information. If the determination unit 240 determines that the first radio 100 is stationary, the sensing unit 250 uses the CSI (Channel State Information) included in the radio information, which was received by the second radio 201 from the first radio 100, to sense the living organism 300 in the target space 400.
[0085] According to this, since sensing within the target space 400 is performed using CSI when the movable first radio 100 is stationary, there is no need to consider the effects of movement by the movable first radio 100, and therefore, accurate sensing of the living organism 300 can be performed.
[0086] Furthermore, the sensing device 200 according to this embodiment further includes a storage unit 260. The storage unit 260 stores multiple 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 multiple index values based on multiple CSIs included in the multiple radio device information. Each of the multiple index values is an index value in a specific index of the CSI to which that index value corresponds among the multiple CSIs.
[0087] According to this method, by determining whether a mobile radio is stationary or not based on multiple CSIs stored for a certain period of time, it is possible to determine whether a radio is stationary or not even if it does not have a sensor that can detect movement.
[0088] (Embodiment 2) Embodiment 2 describes a method for determining the stationary state of a wireless device and sensing a living organism in the case of a SISO (Single-Input Single-Output) system, where both the transmitting antenna and receiving antenna are one.
[0089] [composition] Figure 6 shows an example of the configuration of the sensing system in Embodiment 2.
[0090] The sensing system 1A comprises a first radio 100A and a sensing device 200A.
[0091] The first radio unit 100A comprises a transmitting antenna unit 110A, a transmitting unit 120, and a transmitting signal generation unit 130.
[0092] The transmitting antenna unit 110A has one transmitting antenna element. This single transmitting antenna element transmits a multi-carrier signal (transmitted wave) generated by the transmitting unit 120, which will be described later.
[0093] The transmission signal generation unit 130 generates a multicarrier signal in which multiple subcarrier signals are modulated. Specifically, the transmission signal generation unit 130 generates multiple subcarrier signals corresponding to multiple subcarriers in different frequency bands, and generates a multicarrier signal by multiplexing the generated multiple subcarrier signals. In this embodiment, the transmission signal generation unit 130 is described as generating an OFDM signal consisting of S subcarriers, which has high frequency band utilization efficiency, as the multicarrier signal. However, as long as the multicarrier signal obtained by multicarrier modulation is an OFDM signal in which each subcarrier is orthogonal, other multicarrier signals such as a simple FDM (Frequency Division Multiplexing) signal may be generated.
[0094] Furthermore, the signals generated by the transmission signal generation unit 130 may be shared with signals used for communication.
[0095] The transmitting unit 120 processes the signal generated by the transmitting signal generation unit 130 appropriately to generate a transmission wave. This processing includes, for example, upconversion (converting the signal from the IF (Intermediate Frequency) band to the RF (Radio Frequency) band) and amplification (amplifying the signal to an appropriate transmission level). The transmitting unit 120 outputs the processed multi-carrier signal to the transmitting antenna unit 110A, causing the transmitting antenna unit 110A to transmit the signal. As a result, the multi-carrier signal is transmitted from a single transmitting antenna element of the transmitting antenna unit 110A.
[0096] The sensing device 200A comprises a receiving antenna unit 210A, a receiving unit 220, an acquisition unit 230, a determination 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 the second radio 201A. In other words, in this embodiment, the sensing device 200A can be said to have the second radio 201A.
[0097] The receiving antenna unit 210A has one receiving antenna element. The receiving antenna element receives the signal (received signal) transmitted from one transmitting antenna element and reflected by the living organism 300.
[0098] The receiving unit 220 observes the received signal, which is received by one receiving antenna element and includes a reflected signal obtained by the biological organism 300 from a multicarrier signal transmitted from one transmitting antenna element, for a first period corresponding to a period derived from the activity of the biological organism 300. The period derived from the activity of the biological organism is a biological period (biological fluctuation period) that is half a period or longer of any of the periods of respiration, heartbeat, or body movement of the biological organism 300.
[0099] The receiver 220 converts the high-frequency signal received by a single receiving antenna element into a low-frequency signal that can be processed. The receiver 220 then demodulates the OFDM signal into S subcarrier signals. These S subcarrier signals are also called S IQ symbols. These S subcarrier signals are low-frequency signals.
[0100] The receiving unit 220 further calculates multiple complex transfer functions representing the propagation characteristics between the transmitting antenna element and the receiving antenna element for each subcarrier, based on the S subcarrier signals obtained from the multiple received signals observed over the first period. The receiving unit 220 may continuously observe (or record) the received signals received by the receiving antenna unit 210A and acquire S subcarrier signals continuously or periodically. In other words, the receiving unit 220 may acquire S subcarrier signals at multiple different timings, based on the received signals received at each timing.
[0101] The receiving unit 220 calculates multiple complex transfer functions representing the propagation characteristics between the transmitting antenna element and the receiving antenna element, for each of the multiple subcarriers that each of the multiple subcarrier signals corresponds to.
[0102] In this embodiment, S subcarrier signals are used to calculate S sets of complex transfer functions that represent the propagation characteristics between each transmitting antenna element and each receiving antenna element for each of the S subcarrier signals. The calculated complex transfer function matrix includes reflected waves that do not pass through the biological 300, such as direct waves and reflected waves originating from fixed objects.
[0103] Figure 7 is a diagram illustrating the propagation characteristics at each timing.
[0104] As described above, the propagation characteristic H has a complex transfer function with one type of parameter for each subcarrier. In other words, a different complex transfer function is calculated for each of the multiple different subcarriers.
[0105] Figure 7 shows an image of the propagation characteristic h(t) represented 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. In this case, the propagation characteristic h(t) can be represented as a combination of 1×1×2 blocks. Each block represents one complex transfer function calculated for one receiving antenna element, one transmitting antenna element, and one specific subcarrier. Thus, since the propagation characteristic H is represented by one type of subcarrier parameter, it is represented as a one-dimensional vector. Furthermore, this propagation characteristic h(t) is calculated for each of multiple timings.
[0106] In other words, in this embodiment, the receiving unit 220 receives S subcarrier signals from the transmitting unit 120, and the propagation characteristic h(t) between one transmitting antenna element and one receiving antenna element during the observation time t is expressed as a complex transfer function vector in Equation 7.
[0107]
number
[0108] The acquisition unit 230 acquires radio equipment information, including propagation characteristics h(t) calculated by the receiving unit 220. Propagation characteristics H are an example of CSI (Channel State Information). The acquisition unit 230 acquires multiple radio equipment information over a certain period of time. That is, the acquisition unit 230 acquires radio equipment information at each of several timings over a certain period of time. The multiple radio equipment information acquired by the acquisition unit 230 may be stored in the storage unit 260. The multiple radio equipment information includes multiple propagation characteristics H generated based on multiple received signals acquired at multiple consecutive timings.
[0109] The determination unit 240 determines whether the first radio 100A is stationary or not based on the radio information. Specifically, the determination unit 240 calculates an evaluation value based on multiple index values derived from multiple CSIs included in the multiple radio information stored in the storage unit 260. The evaluation value is an evaluation value used to evaluate the variability of the multiple index values. For example, a larger evaluation value indicates a greater degree of variability in the multiple index values. Then, the determination unit 240 uses the calculated evaluation value to determine whether the first radio 100A, which is a mobile radio, is stationary or not. Each of the multiple index values corresponds to multiple CSIs. In other words, each of the multiple index values corresponds to multiple received signals obtained at multiple different timings. The multiple index values represent the changes in the received signal over time.
[0110] Here, each of the multiple index values is an index value for a specific index of the CSI to which that index value corresponds. The specific index may be, for example, the absolute value (i.e., amplitude) of the CSI. In this case, the multiple index values represent multiple absolute values (amplitudes) corresponding to multiple CSIs. A single index value representing an 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 determines that the first radio 100A is moving if the maximum value of the variance exceeds the predetermined threshold. The determination unit 240 determines that the first radio 100A is stationary if the maximum value of the variance is less than or equal to the predetermined threshold.
[0113] Furthermore, a specific index may be a phase of the CSI. In this case, multiple index values represent multiple phases corresponding to multiple CSIs. A single index value representing a phase is expressed as shown in Equation 9.
[0114]
number
[0115] In this case, the determination unit 240 calculates the time-direction variance 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 determines that the first radio 100A is moving if the maximum value of the variance exceeds the predetermined threshold. The determination unit 240 determines that the first radio 100A is stationary if the maximum value of the variance is less than or equal to the predetermined threshold.
[0116] Furthermore, a specific indicator may be a correlation matrix of CSIs. In this case, multiple indicator values represent multiple correlation matrices corresponding to multiple CSIs. The correlation matrix is calculated as follows.
[0117] The determination 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 shown 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 then vectorizes the upper triangular matrix from the off-diagonal terms into a correlation vector r vec (t) is calculated. Note that the correlation vector is not limited to the upper triangular matrix; it may also be calculated by vectorizing the lower triangular matrix among the off-diagonal terms.
[0120] The determination unit 240 determines the correlation vector r vec Based on (t), the temporal variance is calculated, 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, it determines that the first radio 100A is moving. If the maximum value of the variance is less than or equal to the predetermined threshold, the determination unit 240 determines that the first radio 100A is stationary.
[0121] Although the determination unit 240 is said to calculate the time-direction variance based on multiple index values, it may also calculate covariance instead of variance. Covariance is calculated using, for example, any two of the following: CSI, CSI amplitude, CSI phase, and correlation matrix.
[0122] Furthermore, although the determination unit 240 calculates the maximum value of the variance based on multiple indicator values as an evaluation value, it may calculate at least one of the mean, median, mode, and minimum values, rather than being limited to the maximum value. The determination unit 240 may calculate at least one of the mean, median, mode, maximum, and minimum values of the covariance based on multiple indicator values as an evaluation value. The determination unit 240 may calculate at least one of the mean, median, mode, maximum, and minimum values of multiple indicator values as an evaluation value. Furthermore, the determination unit 240 may calculate two or more combinations of the multiple evaluation values exemplified above as evaluation values. When using two or more combinations of evaluation values, representative values (mean, median, mode, maximum, and minimum) of the two or more evaluation values may be calculated as evaluation values for determining whether a mobile radio is stationary or not.
[0123] Furthermore, the determination unit 240 does not need to calculate an evaluation value for each component of the propagation characteristic H represented in three dimensions, and may calculate an evaluation value for a specific component.
[0124] If the determination unit 240 determines that the first radio 100A is stationary, the sensing unit 250 uses the CSI included in the radio information to sense the living organism 300 in the target space 400. The sensing unit 250 may use multiple CSIs to detect the position of the living organism 300 in the target space 400, identify the posture of the living organism 300, identify the living organism 300 based on a CSI registered in advance for each individual living organism 300, or identify the movement of the living organism 300.
[0125] The operation of sensing device 200A can be explained in the same way as sensing device 200, so the explanation will be omitted.
[0126] (Variation 1) In the above embodiment, the sensing devices 200 and 200A may be configured separately from the second radios 201 and 201A. In this case, the sensing devices 200 and 200A may acquire radio information, including propagation characteristics H calculated based on the received signals received by the second radios 201 and 201A, by communicating with the second radios 201 and 201A.
[0127] (Modification 2) In the above embodiment, the second radios 201 and 201A were described as fixed routers, but they may also be composed of movable devices, similar to the first radios 100 and 100A. In this case as well, the sensing devices 200 and 200A can determine whether both the first radios 100 and 100A and the second radios 201 and 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 a predetermined threshold, it is determined that one of the first radios 100 and 100A and the second radios 201 and 201A is moving, and if the evaluation value is less than or equal to the predetermined threshold, it is determined that both the first radios 100 and 100A and the second radios 201 and 201A are stationary.
[0128] (Variation 3) In the above embodiment, it was stated that the determination of whether both the first radios 100, 100A and the second radios 201, 201A are stationary is made based on the CSI, but the embodiment is not limited to this. For example, consider the case where the first radios 100, 100A are movable and the second radios 201, 201A are fixed. In this case, the first radios 100, 100A have sensors for detecting the movement of the first radios 100, 100A, and the sensing device 200 may acquire the detection results from the sensors as radio information from the first radios 100, 100A. The sensing device 200 may determine whether the first radios 100, 100A are moving or stationary based on the detection results. The sensors may be, for example, acceleration sensors, angular velocity sensors, or GPS (Global Positioning System) sensors. Furthermore, if the second radio units 201 and 201A are also movable, they may also have sensors for detecting movement, similar to the first radio units 100 and 100A, and the sensing device 200 may determine whether the second radio units 201 and 201A are moving or stationary based on the detection results of these sensors. This is also true when the first radio units 100 and 100A are fixed and the second radio units 201 and 201A are movable. Thus, the sensing device 200 may determine whether both the first radio units 100 and 100A and the second radio units 201 and 201A are stationary based on the detection results of sensors for detecting movement obtained from all movable radio units.
[0129] According to this, by determining whether a mobile radio is stationary or not based on sensing information obtained from at least one of the following sensors—an acceleration sensor, an angular velocity sensor, and a GPS sensor—it is possible to accurately determine whether a mobile radio is stationary or not.
[0130] (Modification 4) In the above embodiment, the mobile radio may hold an identifier for identifying the mobile radio, and may include this identifier in the transmission signal. This allows the sensing device 200 to identify the mobile radio.
[0131] (Variation 5) In the above embodiment, the sensing devices 200 and 200A, which include the first radios 100 and 100A and the second radios 201 and 201A, are configured as separate units. However, the system is not limited to this configuration, and the devices may be integrated. Even in this case, the sensing devices 200 and 200A can determine whether the integrated first radios 100 and 100A and the second radios 201 and 201A are stationary or not using the same method as in the above embodiment.
[0132] (Experimental variation 6) In the above embodiment 1, the complex transfer function matrix is vectorized, but this is not required. Also, in the above embodiment 1, 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 method, receiving antenna element direction, and subcarrier direction may also be vectorized.
[0133] (others) Figure 8 shows the experimental results of evaluation values that assess whether the radio is stationary or not based on CSI.
[0134] Figure 8 shows the IQ waveform, amplitude, unwrapped phase, amplitude variance, unwrapped phase variance, and correlation matrix variance obtained from the CSI for a stationary state, a state where the mobile radio is moving slightly, and a state where the mobile radio is moving significantly. As shown in Figure 8, the changes are small when the radio is stationary, and the changes become larger as the movement increases. Thus, by calculating the amplitude, phase, correlation matrix, and their variances as evaluation values, it is possible to determine whether the mobile radio is moving or stationary.
[0135] In each of the above embodiments, each component may be implemented by dedicated hardware or by executing a software program suitable for each component. Each component may also be implemented 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, this disclosure can be implemented not only as a sensing device equipped with 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 implemented as a computer program that causes a computer to execute each of the characteristic steps included in such a method. And it goes without saying that such a computer program can be distributed via a computer-readable non-temporary recording medium such as a CD-ROM or via a communication network such as the Internet. [Industrial applicability]
[0137] This disclosure can be used in sensing devices and sensing methods that estimate the distance and position of living organisms using wireless signals, and in particular in measuring instruments that measure the distance and position of living organisms, including living organisms and machines, home appliances that perform control according to the distance and position of living organisms, and monitoring devices that detect the intrusion of living organisms. [Explanation of Symbols]
[0138] 1. 1A Sensing System 100, 100A First 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 Receiver 230 Acquisition Department 240 Judgment section 250 Sensing Unit 260 Storage section 300 living organisms 400 Target space
Claims
1. A first wireless device placed in the target space and capable of wireless transmission, A second radio device, which is arranged in the aforementioned target space and capable of receiving wireless signals, At least one of the first radio and the second radio is a portable radio, and includes an acquisition unit that acquires radio information obtained by at least one of the first radio and the second radio, A storage unit that stores information on multiple radio devices acquired over a certain period of time, (i) an evaluation value calculated from multiple index values based on multiple CSIs (Channel State Information) contained in multiple radio device information stored in the memory unit, or (ii) an evaluation value calculated from the index value of a specific index of the CSI corresponding to the multiple index values based on multiple CSIs stored in the memory unit, a determination unit that determines whether the movable radio device is stationary or not, The sensing unit comprises the following: If the determination unit determines that the movable wireless device is stationary, it uses the CSI included in the wireless device information, which is transmitted from the first wireless device and received by the second wireless device, to sense living organisms in the target space; and if the determination unit determines that the movable wireless device is moving, it does not perform the sensing of living organisms in the target space. Sensing device.
2. The aforementioned specific indicator includes the absolute value of the CSI. The sensing device according to claim 1.
3. The aforementioned specific indicator includes the phase of the CSI. The sensing device according to claim 1.
4. The aforementioned specific indicator includes the correlation matrix of the CSI. The sensing device according to claim 1.
5. The evaluation value includes the variance or covariance of the multiple indicator values. A sensing device according to any one of claims 1 to 4.
6. The evaluation value includes at least one of the mean, median, mode, maximum, and minimum values of the plurality of indicator values or the variance or covariance of the plurality of indicator values. A sensing device according to any one of claims 1 to 4.
7. A sensing method performed by a sensing device, The system acquires radio information obtained by at least one of the following radios: a first radio located in the target space and capable of wireless transmission, and a second radio located in the target space and capable of wireless reception; and at least one of the first and second radios is a movable radio. It stores information on multiple radio devices acquired over a certain period of time. (i) an evaluation value calculated from multiple index values based on multiple CSIs (Channel State Information) contained in multiple stored radio device information, or (ii) an evaluation value calculated from the index value of a specific index of the CSI corresponding to the multiple index values based on multiple stored CSIs, to determine whether the mobile radio device is stationary or not. If the determination determines that the movable radio is stationary, the CSI included in the radio information, which is transmitted from the first radio and received by the second radio, is used to perform sensing of living organisms in the target space. If the determination determines that the movable radio is moving, the sensing of living organisms in the target space is not performed. Sensing method.
8. A program for causing a computer to execute the sensing method described in claim 7.