Analysis device, program for causing a computer to execute the program, and computer-readable recording medium on which the program is recorded

Abstract

To provide an analysis apparatus which can estimate a transmission source node even if decoding of a radio frame fails.SOLUTION: A detection processing unit 122 outputs, to an estimation processing unit 123, a signal Sig_IQ detected based on IQ data (D1_env). The estimation processing unit 123 determines, when absence of header data corresponding to the signal Sig_IQ is determined, a first characteristic value which is a characteristic value indicating characteristics of a transmission path of a radio frame, on the basis of the signal Sig_IQ in the case of the absence of header data corresponding to the signal Sig_IQ, detects, from a storage unit 124, a transmission source having a characteristic value closest to the determined first characteristic value, executes estimation processing to estimate the detected transmission source as a transmission source of the radio frame, and acquires, when presence of the header data corresponding to the signal Sig_IQ is determined, a transmission source of the radio frame from the header data corresponding to the signal Sig_IQ.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an analysis device, a program to be executed by a computer, and a computer-readable recording medium on which the program is recorded. [Background technology]

[0002] IoT (Internet of Things) devices are increasingly being introduced into indoor environments such as factories, hospitals, and commercial facilities for the purpose of understanding and controlling the operating status of various equipment.

[0003] For example, when wireless communication is used to manage and control the status of a manufacturing system in a factory environment, if communication is interrupted due to radio wave attenuation or interference, it can lead to delays or even the halt of the manufacturing process. For this reason, particularly high quality is required for wireless communication.

[0004] In order to prevent deterioration of wireless quality, it is important for a network administrator to grasp the current wireless quality in a target environment in as much detail as possible. Therefore, for example, it is important to install a sensor node in the target environment and acquire and analyze data related to wireless quality at the sensor node. Useful data for grasping wireless quality include a time series (envelope data) of received signal strength (RSS) and a time series (header data) of header information of each received frame. Furthermore, by acquiring the timestamp of the envelope data and the timestamp of the header data synchronously on the same time axis, it becomes possible to grasp the RSS state at the time of transmission of each frame, which is useful for grasping wireless quality in detail (see, for example, Patent Document 1).

[0005] Furthermore, in understanding wireless quality, it is important to identify the source node of each wireless frame, because information on the source node can be used to estimate the wireless resource utilization rate for each node, for example.

[0006] Header data is one type of data that is acquired to identify the source node. One method for acquiring header data is to run a packet capture program such as tcpdump (Non-Patent Document 1) on a PC (Personal Computer) equipped with a commercially available wireless LAN (Local Area Network) interface. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2019-161290 [Non-patent literature]

[0008] [Non-Patent Document 1] https: / / www.tcpdump.org / [Non-patent document 2] k.-W. Yip, Y.-C. Wu, and T.-S. Ng: Timing-Synchronization Analysis for IEEE 802.11a Wireless LANs in Frequency-Nonselective Rician Fading Environments, IEEE trans. on Wireless Communications, Vol. 3, No. 2, pp. 387-394, 2004. Summary of the Invention [Problem to be solved by the invention]

[0009] However, it is only possible to identify the source node using the header data of received wireless frames that are successfully decoded.For example, for wireless frames that fail to be decoded due to reasons such as "interference," it is not possible to identify the source node using the header data alone.

[0010] Therefore, according to an embodiment of the present invention, an analysis device is provided that can estimate a source node even if decoding of a wireless frame fails.

[0011] Furthermore, according to an embodiment of the present invention, there is provided a program for causing a computer to identify a source node even if decoding of a wireless frame fails.

[0012] Furthermore, according to an embodiment of the present invention, there is provided a computer-readable recording medium having recorded thereon a program for causing a computer to identify a source node even if decoding of a wireless frame fails. [Means for solving the problem]

[0013] (Configuration 1) According to an embodiment of the present invention, the analysis device includes a reception processing unit, a synchronization processing unit, a detection processing unit, a storage unit, and an estimation processing unit. The reception processing unit receives IQ data, which is data obtained by down-converting the frequency of a received signal when a wireless frame is received, from a sensor device, and receives header data of the wireless frame from a header data detection device. The synchronization processing unit synchronizes the IQ data and the header data received by the reception processing unit. The detection processing unit detects a signal Sig_IQ based on the IQ data synchronized by the synchronization processing unit and the IQ data of the header data. The storage unit stores Z (Z is an integer greater than or equal to 2) transmission sources, each of which is a transmission source of a wireless frame, Z pieces of transmission source identification information respectively associated with the Z transmission sources, and Z characteristic values respectively associated with the Z transmission source identification information, the Z characteristic values being characteristic values specific to a transmission path between a transmitter and a receiver of the wireless frame. When the estimation processing unit determines that no header data corresponding to the signal Sig_IQ detected by the detection processing unit is present, it calculates a first characteristic value, which is a characteristic value specific to the transmission path between the transmitter and receiver of the wireless frame, based on the signal Sig_IQ when no header data is present, detects a sender having a characteristic value closest to the calculated first characteristic value from Z senders stored in the memory unit, and performs an estimation process to estimate the detected sender as the sender of the wireless frame.When it determines that header data corresponding to the signal Sig_IQ detected by the detection processing unit is present, it obtains the sender of the wireless frame from the header data corresponding to the signal Sig_IQ.

[0014] (Configuration 2) In configuration 1, when the estimation processing unit determines that header data corresponding to the signal Sig_IQ detected by the detection processing unit is present, it acquires the source of the wireless frame, and then performs a storage process to calculate a second characteristic value, which is a characteristic value specific to the transmission path between the transmitter and receiver of the wireless frame, for the acquired source of the wireless frame based on the signal Sig_IQ when the header data is present, and store the second characteristic value in association with the source that matches the source of the wireless frame acquired from the header data, among the Z sources stored in the memory unit.

[0015] (Configuration 3) In configuration 2, in the storage process, the estimation processing unit calculates the frequency response in the transmission path between the transmitter and receiver of the wireless frame based on the signal Sig_IQ when header data is present, averages the phase characteristics of the calculated frequency response for each subcarrier to calculate an average phase characteristic, and executes a first average phase characteristic extraction process to calculate a pair of the calculated average phase characteristic and the start sample number of the preamble of the signal Sig_IQ (start sample number, average phase characteristic) as a second characteristic value.

[0016] (Configuration 4) In any of configurations 1 to 3, the estimation processing unit performs a determination process in which, when the non-overlapping time between the duration of signal Sig_IQ and the duration of header data in the IQ data and header data synchronized by the synchronization processing unit is less than or equal to a first threshold, it determines that header data corresponding to signal Sig_IQ detected by the detection processing unit is present, and when the non-overlapping time is longer than the first threshold, it determines that header data corresponding to signal Sig_IQ detected by the detection processing unit is not present.

[0017] (Configuration 5) In the configuration 4, the detection processing unit detects the sample d of the signal Sig_IQ. i (i indicates the order of sample acquisition, i = 0, 1, 2,...) i The timestamp t when .rss first exceeded the second threshold start to signal strength d i After the RSS first exceeds the second threshold, the signal strength d i The timestamp when .rss first fell below the second threshold. i Time until .ts d i .ts-t startas the duration of signal Sig_IQ and outputs the determined duration of signal Sig_IQ to the estimation processing unit. Upon receiving the duration of signal Sig_IQ from the detection processing unit, the estimation processing unit determines a non-overlapping time based on the duration of signal Sig_IQ and the duration of the header data, and performs a determination process based on the determined non-overlapping time.

[0018] (Configuration 6) In any of configurations 1 to 5, the estimation processing unit, in the estimation process, calculates a frequency response in the transmission path between the transmitter and receiver of the wireless frame based on the preamble of the signal Sig_IQ when header data is not present, performs processing to prevent the phase difference between adjacent subcarriers from exceeding π with respect to the phase characteristic of the calculated frequency response, thereby acquiring the phase characteristic of the frequency response in which the phase difference between adjacent subcarriers is π or less, averages the phase characteristics of the acquired frequency response for the subcarriers to calculate an average phase characteristic, and executes a second average phase characteristic extraction process to obtain a pair of the calculated average phase characteristic and the start sample number of the preamble (start sample number, average phase characteristic) as a first characteristic value.

[0019] (Configuration 7) In configuration 6, in the second average phase characteristic extraction process, the estimation processing unit obtains a frequency response by dividing the calculation result obtained by fast Fourier transforming the Long Training Field portion of the preamble of frame j consisting of signal Sig_IQ detected by the detection processing unit by the calculation result obtained by fast Fourier transforming the Long Training Field portion of the preamble of a frame consisting of a known signal.

[0020] (Configuration 8) In configuration 6 or 7, in the second average phase characteristic extraction process, the estimation processing unit further determines whether the first sample number of the preamble has been identified for the signal Sig_IQ detected by the detection processing unit, and when it determines that the first sample number has been identified, it obtains the pair (starting sample number, average phase characteristic) as the first characteristic value.

[0021] (Configuration 9) In the configuration 8, when the estimation processing unit determines that the first sample number cannot be identified in the second average phase characteristic extraction processing, it terminates the estimation processing.

[0022] (Configuration 10) In any one of the sixth to ninth configurations, the first characteristic value is a starting sample number s of a frame j of the signal Sig_IQ detected by the detection processing unit. j1 and the average phase characteristic m j1 In the estimation process, the estimation processing unit calculates the starting sample number and the average phase characteristic obtained in the second average phase characteristic extraction process as s j1 ,m j1 A set of characteristic values (s j ,m j ) is processed to change the order of addition to the memory section to the set of characteristic values (s j ,m j ) as a set of characteristic values (s k ,m k )(k=1,2,...,n fifo (n fifo is the maximum number of characteristic values that can be stored in association with one source. k =s k+1 -s k (k=1,2,...,N(=n fifo -1)) is the explanatory variable, and y k =m k+1 -m k (k=1,2,...,N(=n fifo A phase change rate estimation process is performed to obtain a phase change rate β1, which is the slope of a regression function with the objective function being the phase change rate β1. The phase change rate β1 obtained in the phase change rate estimation process is used to obtain the most recent characteristic value (s j0 ,m j0 ) and the characteristic value of frame j (s j1 ,m j1 ) error e uThe calculation is performed for all Z transmission sources stored in the storage unit to obtain Z errors, and the transmission source that obtains the smallest error among the obtained Z errors is estimated to be the transmission source of the wireless frame.

[0023] (Configuration 11) In configuration 10, when the minimum error is equal to or less than a third threshold in the estimation process, the estimation processing unit further estimates the source when the minimum error equal to or less than the third threshold is obtained as the source of the wireless frame.

[0024] (Configuration 12) According to an embodiment of the present invention, a program is executed in the analysis device according to any one of configurations 1 to 11, The analysis device is a storage unit that stores Z (Z is an integer equal to or greater than 1) transmission sources, each of which is a transmission source of a wireless frame, Z pieces of transmission source identification information associated with the Z transmission sources, and Z characteristic values associated with the Z transmission source identification information, each of which is a characteristic value specific to a transmission path between a transmitter and a receiver of the wireless frame; The program is a first step in which a reception processing unit receives, from a sensor device, IQ data, which is data obtained by down-converting the frequency of a received signal when a wireless frame is received, and receives, from a header data detection device, header data of the wireless frame; a second step in which a synchronization processor synchronizes the IQ data and header data received in the first step; a third step in which the detection processing unit detects the signal Sig_IQ based on the IQ data of the IQ data and the header data synchronized in the second step; This is a program for causing a computer to execute the following steps: when the estimation processing unit determines that no header data corresponding to the signal Sig_IQ detected in the third step exists, it calculates a first characteristic value, which is a characteristic value specific to the transmission path between the transmitter and receiver of the wireless frame, based on the signal Sig_IQ when no header data exists, detects a sender having a characteristic value closest to the calculated first characteristic value from Z senders stored in a memory unit, and estimates the detected sender as the sender of the wireless frame; and when it determines that header data corresponding to the signal Sig_IQ detected by the detection processing unit exists, it acquires the sender of the wireless frame from the header data corresponding to the signal Sig_IQ.

[0025] (Configuration 13) In configuration 12, when the estimation processing unit determines in the fourth step that header data corresponding to the signal Sig_IQ detected in the third step is present, it acquires the source of the wireless frame, and then further calculates a second characteristic value, which is a characteristic value specific to the transmission path between the transmitter and receiver of the wireless frame, for the acquired source of the wireless frame based on the signal Sig_IQ when header data is present, and performs a storage process to store the second characteristic value in association with the source that matches the source of the wireless frame acquired from the header data, among the Z sources stored in the memory unit.

[0026] (Configuration 14) In configuration 13, in the storage process of the fourth step, the estimation processing unit calculates the frequency response in the transmission path between the transmitter and receiver of the wireless frame based on the signal Sig_IQ when header data is present, averages the phase characteristics of the calculated frequency response for each subcarrier to calculate an average phase characteristic, and executes a first average phase characteristic extraction process to calculate a pair of the calculated average phase characteristic and the start sample number of the preamble of the signal Sig_IQ (start sample number, average phase characteristic) as a second characteristic value.

[0027] (Configuration 15) In any of configurations 12 to 14, in a fourth step, the estimation processing unit performs a determination process in which, when the non-overlapping time between the duration of signal Sig_IQ and the duration of header data in the IQ data and header data synchronized in the second step is less than or equal to a first threshold, it determines that header data corresponding to signal Sig_IQ detected in the third step exists, and when the non-overlapping time is longer than the first threshold, it determines that header data corresponding to signal Sig_IQ detected in the third step does not exist.

[0028] (Configuration 16) In the configuration 15, the detection processing unit, in the third step, i (i indicates the order of sample acquisition, i = 0, 1, 2,...) i The timestamp t when .rss first exceeded the second threshold start to signal strength d i After the RSS first exceeds the second threshold, the signal strength d i The timestamp when .rss first fell below the second threshold. i Time until .ts d i .ts-t start as the duration of signal Sig_IQ and outputs the determined duration of signal Sig_IQ to the estimation processing unit. In the fourth step, upon receiving the duration of signal Sig_IQ from the detection processing unit, the estimation processing unit determines a non-overlapping time based on the duration of signal Sig_IQ and the duration of the header data, and performs a determination process based on the determined non-overlapping time.

[0029] (Configuration 17) In any of configurations 12 to 16, in the estimation process of the fourth step, the estimation processing unit calculates a frequency response in the transmission path between the transmitter and receiver of the wireless frame based on the preamble of the signal Sig_IQ when header data is not present, performs processing to prevent the phase difference between adjacent subcarriers from exceeding π with respect to the phase characteristic of the calculated frequency response, acquires a phase characteristic of the frequency response in which the phase difference between adjacent subcarriers is π or less, averages the phase characteristics of the acquired frequency response for the subcarriers to calculate an average phase characteristic, and executes a second average phase characteristic extraction process to acquire a pair of the calculated average phase characteristic and the start sample number of the preamble (start sample number, average phase characteristic) as a first characteristic value.

[0030] (Configuration 18) In configuration 17, in the second average phase characteristic extraction process of the fourth step, the estimation processing unit obtains a frequency response by dividing the calculation result obtained by fast Fourier transforming the Long Training Field portion of the preamble of frame j consisting of signal Sig_IQ detected in the third step by the calculation result obtained by fast Fourier transforming the Long Training Field portion of the preamble of a frame consisting of a known signal.

[0031] (Configuration 19) In configuration 17 or 18, in the second average phase characteristic extraction process of the fourth step, the estimation processing unit further determines whether the first sample number of the preamble has been identified for the signal Sig_IQ detected in the third step, and when it determines that the first sample number has been identified, it obtains the pair (starting sample number, average phase characteristic) as the first characteristic value.

[0032] (Configuration 20) In configuration 19, when the estimation processing unit determines in the fourth step that the first sample number has not been identified in the second average phase characteristic extraction processing, it ends the estimation processing.

[0033] (Configuration 21) In any of the configurations 17 to 20, the first characteristic value is the starting sample number s of the frame j of the signal Sig_IQ detected in the third step. j1 and the average phase characteristic m j1 It consists of:

[0034] In the estimation process of the fourth step, the estimation processing unit calculates the starting sample number and the average phase characteristic obtained in the second average phase characteristic extraction process as s j1 ,m j1 A set of characteristic values (s j ,m j ) is processed to change the order of addition to the memory section to the set of characteristic values (s j ,m j ) as a set of characteristic values (s k ,m k )(k=1,2,...,n fifo (n fifo is the maximum number of characteristic values that can be stored in association with one source. k =s k+1 -s k (k=1,2,...,N(=n fifo -1)) is the explanatory variable, and y k =m k+1 -m k (k=1,2,...,N(=n fifo A phase change rate estimation process is performed to obtain a phase change rate β1, which is the slope of a regression function with the objective function being the phase change rate β1. The phase change rate β1 obtained in the phase change rate estimation process is used to obtain the most recent characteristic value (s j0 ,m j0 ) and the characteristic value of the frame j (s j1 ,m j1 ) error e u The calculation is performed for all Z transmission sources stored in the storage unit to obtain Z errors, and the transmission source that obtains the smallest error among the obtained Z errors is estimated to be the transmission source of the wireless frame.

[0035] (Configuration 22) In configuration 21, in the estimation process of the fourth step, when the minimum error is equal to or less than a third threshold, the estimation processing unit further estimates the source when the minimum error equal to or less than the third threshold is obtained as the source of the wireless frame.

[0036] (Configuration 23) Furthermore, according to an embodiment of the present invention, the recording medium is a computer-readable recording medium on which the program according to any one of the twelfth to twenty-second configurations is recorded. [Effects of the Invention]

[0037] Even if the decoding of a wireless frame fails, the source node can be estimated. [Brief explanation of the drawings]

[0038] [Figure 1] 1 is a schematic diagram of a wireless communication system according to an embodiment of the present invention; [Figure 2] FIG. 2 is a schematic diagram of the analysis device, sensor device, and personal computer shown in FIG. [Figure 3] FIG. 3 is a schematic diagram of a source estimation unit shown in FIG. 2. [Figure 4] 4 is a schematic diagram illustrating a configuration of a synchronization processing unit shown in FIG. 3. [Figure 5] FIG. 10 is a diagram for explaining a graphical representation of envelope data. [Figure 6] 10A and 10B are diagrams for explaining a synchronization detection data generation process. [Figure 7] FIG. 1 is a conceptual diagram showing frame durations and frame types. [Figure 8] 10 is a flowchart illustrating an offset acquisition process. [Figure 9] 9 is a flowchart for explaining the detailed operation of step S2 in FIG. 8. [Figure 10] 9 is a first flowchart for explaining the detailed operation of step S3 in FIG. 8. [Figure 11]10 is a second flowchart illustrating the detailed operation of step S3 in FIG. 8. [Figure 12] 9 is a flowchart for explaining the detailed operation of step S4 in FIG. 8. [Figure 13] FIG. 10 is a diagram for explaining a signal detection process. [Figure 14] 4 is a diagram showing a processing flow in the transmission source estimation unit 12 shown in FIGS. 2 and 3. FIG. [Figure 15] 10A and 10B are diagrams for explaining a method for determining whether or not header data corresponding to a signal Sig_IQ detected in a signal detection process exists. [Figure 16] 4 is a flowchart for explaining the operation of a detection processing unit and an estimation processing unit shown in FIG. 3. [Figure 17] 17 is a flowchart for explaining the signal detection process in step S11 of FIG. 16. [Figure 18] 10 is a flowchart illustrating an average phase characteristic extraction process. [Figure 19] FIG. 17 is a diagram for explaining the source estimation process in step S18 of FIG. [Figure 20] 20 is a flowchart for explaining a phase change rate estimation process in step S188 of FIG. 19. [Figure 21] 17 is a flowchart for explaining the detailed operation of step S17 in the flowchart shown in FIG. 16. [Figure 22] FIG. 20 is a diagram for explaining the reason why the average phase characteristic extraction process is terminated when it is determined in step S152 of FIG. 18 that the first sample number of the preamble has not been identified. DETAILED DESCRIPTION OF THE INVENTION

[0039] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in which like or corresponding parts are designated by like reference numerals and will not be described repeatedly.

[0040] 1 is a schematic diagram of a wireless communication system according to an embodiment of the present invention. Referring to Fig. 1, wireless communication system 100 according to the embodiment of the present invention includes analysis device 10, sensor devices 20, 30, and 40, a personal computer (PC) 50, and communication devices 60, 70, and 80.

[0041] A personal computer (PC) 50 executes, for example, the packet capture program tcpdump described in Non-Patent Document 1 to acquire header data, and transmits the acquired header data to the analysis device 10.

[0042] The communication devices 60, 70, and 80 are installed, for example, in a narrow space (for example, in a factory). The communication devices 60, 70, and 80 can wirelessly communicate with each other in accordance with wireless LAN standards such as IEEE802.11a, IEEE802.11g, IEEE802.11n, IEEE802.11ac, and IEEE802.11ax. The communication devices 60, 70 and / or the communication device 80 are, for example, machine tools with wireless communication capabilities.

[0043] The analysis device 10 and one or more sensor devices are connected wirelessly or by wire, and can communicate with each other.

[0044] Furthermore, the analysis device 10 and the personal computer 50 with wireless communication capabilities are connected wirelessly or via a wire, and can communicate with each other.

[0045] FIG. 2 is a schematic diagram of the analysis device 10, the sensor device 20, and the personal computer 50 shown in FIG.

[0046] Referring to FIG. 2, analysis device 10 includes a third communication interface (IF) 11 and a transmission source estimation unit 12.

[0047] The sensor device 20 includes an antenna 21 , an RF processing unit 22 , a synchronization time management unit 23 , an IQ data acquisition unit 24 , an envelope data acquisition unit 25 , a synchronization detection data generation unit 26 , and a first communication IF 27 .

[0048] The personal computer (PC) 50 includes an antenna 51, an RF processing unit 52, a BB processing unit 53, a header acquisition processing unit 54, and a second communication IF 55.

[0049] The antenna 21 of the sensor device 20 is an antenna for receiving radio waves (RF signals) radiated (transmitted) from the outside. The antenna 21 may be a transmitting and receiving antenna.

[0050] The RF processing unit 22 receives an RF signal from the outside via the antenna 21, performs RF processing for reception (RF demodulation processing, AD conversion, etc.) on the received RF signal, and acquires a post-RF processing signal Sig0 (for example, a baseband OFDM signal).The RF processing unit 22 then outputs the post-RF processing signal Sig0 to the IQ data acquisition unit 24.

[0051] The synchronization time management unit 23 manages time information (clock information) and generates a control signal Ctl_t for determining the timing of acquiring IQ data based on the time information (clock information). The synchronization time management unit 23 then outputs the generated control signal Ctl_t to the IQ data acquisition unit 24. The synchronization time management unit 23 may generate the control signal Ctl_t based on time information acquired by a clock unit (not shown) provided in the sensor device 20, or may acquire (e.g., via the first communication interface 27) time information synchronized with other sensor devices from an external device (e.g., an external device (e.g., the analysis device 10) that holds time information (clock information) synchronized with other sensor devices using PTP (Precision Time Protocol) or the like) and generate the control signal Ctl_t based on the time information.

[0052] The IQ data acquisition unit 24 receives the signal Sig0 output from the RF processing unit 22 and the control signal Ctl_t output from the synchronization time management unit 23. The IQ data acquisition unit 24 then acquires data (I component data) of the I component signal (in-phase component signal) and data (Q component data) of the Q component signal (quadrature component signal) from the signal Sig0 at a timing determined by the control signal Ctl_t, and outputs the acquired data as data D1_IQ to the envelope data acquisition unit 25 and the synchronization detection data generation unit 26. The data D1_IQ is composed of sample data (time series data), and the ith (i is an integer) sample data of the data D1_IQ is represented by d i and the sample data d that composes the data D1_IQ is i Let the set of i}. Also, the sample data d of data D1_IQ i The timestamp (time information at the time of acquisition) of i The IQ data acquisition unit 24 acquires the sample data d of the data D1_IQ. i The time information of the time when the synchronization time management unit 23 acquired the time stamp d i .ts and the timestamp d i .ts shall be included in data D1_IQ.

[0053] The envelope data acquisition unit 25 receives the data D1_IQ output from the IQ data acquisition unit 24, and acquires time-series data D1_env of the signal strength from the data D1_IQ. The envelope data acquisition unit 25 then outputs the acquired data D1_env to the first communication interface 27.

[0054] The synchronization detection data generating unit 26 receives the data D1_IQ output from the IQ data acquiring unit 24. The synchronization detection data generating unit 26 then executes a synchronization detection data generating process on the data D1_IQ to generate synchronization detection data D1_p (time-series data including only a timestamp as an attribute). The synchronization detection data generating unit 26 then outputs the generated synchronization detection data D1_p to the first communication interface 27. The data D1_p is made up of sample data (time-series data), and the ith (i is a natural number) sample data of the data D1_p is called p i and the sample data p that composes the data D1_p is i Let the set of p i}. Also, sample data p of data D1_p i The timestamp (time information at the time of acquisition) of p i It is written as .ts.

[0055] The first communication interface 27 is a communication interface for transmitting and receiving data to and from an external device, for example, via a wired or wireless network (including a communication path conforming to a predetermined serial bus standard (e.g., USB or PCI Express)). The first communication interface 27 receives the data D1_env output from the envelope data acquisition unit 25 and the data D1_p output from the synchronization detection data generation unit 26, converts the received data into data in a format that can be communicated via a wired or wireless network, and transmits the data to the analysis device 10. Note that the transmission data of the data D1_env is referred to as transmission data Dtx(D1_env), the transmission data of the data D1_p is referred to as transmission data Dtx(D1_p), and the transmission data Dtx(D1_env) and the transmission data Dtx(D1_p) are collectively referred to as transmission data Dtx(S_node1) of the sensor device 20.

[0056] Each of the sensor device 30 and the sensor device 40 has the same configuration as the sensor device 20 shown in FIG.

[0057] The personal computer (PC) 50 is realized by, for example, a commercially available personal computer equipped with a wireless communication interface (a commercially available personal computer equipped with a wireless communication interface card). Note that Fig. 2 shows only the functional units of the personal computer (PC) 50 that are necessary for acquiring the header data of the wireless signal.

[0058] The antenna 51 is an antenna for receiving radio waves (RF signals) radiated (transmitted) from the outside. The antenna 51 may be a transmitting and receiving antenna.

[0059] The RF processing unit 52 receives an RF signal from the outside via the antenna 51, performs RF processing for reception (RF demodulation processing, AD conversion, etc.) on the received RF signal, and obtains a post-RF-processing signal SigBB (for example, a baseband OFDM signal).The RF processing unit 52 then outputs the post-RF-processing signal SigBB to the BB processing unit 53.

[0060] The BB processing unit 53 acquires a baseband demodulated signal D0 by performing baseband demodulation processing (for example, when the modulation method is OFDM, processing such as guard interval (GI) removal processing, FFT conversion, demapping processing, parallel / serial conversion, etc.) on the RF demodulated signal SigBB output from the RF processing unit 52. Then, the BB processing unit 53 outputs the acquired baseband demodulated signal D0 to the header acquisition unit 54.

[0061] The header acquisition unit 54 receives the baseband demodulated signal D0 output from the BB processing unit 53. The header acquisition unit 54 executes a header acquisition process on the baseband demodulated signal D0 to acquire header data. Note that the "header data" refers to time-series data obtained by extracting information from the header portion of each frame of a sequence of frames obtained by decoding a bit string after demodulation based on the specifications of a wireless system (e.g., IEEE802.11a, etc.).

[0062] Then, the header acquisition unit 54 outputs the data including the acquired header data to the second communication interface 55 as data D2_head.

[0063] The second communication interface 55 is a communication interface for transmitting and receiving data to and from an external device, for example, via a wired or wireless network (including a communication path conforming to a predetermined serial bus standard (e.g., USB or PCI Express)). The second communication interface 55 inputs the data D2_head output from the header acquisition unit 54, converts the input data into data in a format that can be communicated via a wired or wireless network, and transmits the converted data to the analysis device 10. Note that the data to be transmitted of the data D2_head is referred to as transmission data Dtx(D2_head), and the data to be transmitted from the personal computer 50 to the analysis device 10 is referred to as Dtx(PC1).

[0064] The third communication interface 11 of the analysis device 10 is a communication interface for transmitting and receiving data to and from an external device, for example, via a wired or wireless network (including a communication path conforming to a predetermined serial bus standard (e.g., USB or PCI Express)). The third communication interface 11 receives transmission data Dtx(S_node1) from the sensor device 20 and transmission data Dtx(PC1) from the personal computer 50 via the network.

[0065] The third communication interface 11 extracts envelope data D1_env from the transmission data Dtx(D1_env) from the sensor device 20, and outputs the extracted envelope data D1_env to the transmission source estimation unit 12. The third communication interface 11 also extracts synchronization detection data D1_p from the transmission data Dtx(D1_p) from the sensor device 20, and outputs the extracted synchronization detection data D1_p to the transmission source estimation unit 12. Furthermore, the third communication interface 11 extracts header data D2_head from the transmission data Dtx(PC1) from the personal computer 50, and outputs the extracted header data D2_head to the transmission source estimation unit 12.

[0066] The transmission source estimation unit 12 receives the envelope data D1_env, the synchronization detection data D1_p, and the header data D2_head from the third communication interface 11. Then, the transmission source identification unit 12 estimates the transmission source based on the envelope data D1_env, the synchronization detection data D1_p, and the header data D2_head by a method described later.

[0067] Fig. 3 is a schematic diagram of transmission source estimation unit 12 shown in Fig. 2. Referring to Fig. 3, transmission source estimation unit 12 includes a synchronization processing unit 121, a detection processing unit 122, an estimation processing unit 123, and a storage unit .

[0068] The synchronization processing unit 121 receives the synchronization detection data D1_p and the header data D2_head from the third communication interface 11. Then, the synchronization processing unit 121 executes an offset calculation process using the sample data of the synchronization detection data D1_p and the sample data of the header data D2_head, and calculates an offset value e opt After that, the synchronization processing unit 121 calculates the offset value e opt The timestamp of the header data is corrected (adjusted) based on the timestamp of the header data, and the corrected header data D2′_head with the corrected timestamp is output to the estimation processing unit 123.

[0069] As a result of the correction process (adjustment process) by the synchronization processing unit 121, the corrected header data D2'_head is synchronized with the envelope data D1_env.

[0070] The detection processing unit 122 receives the envelope data D1_env from the third communication interface 11, detects the signal Sig_IQ from the received envelope data D1_env, and outputs the detected signal Sig_IQ to the estimation processing unit 123.

[0071] The estimation processing unit 123 receives the signal Sig_IQ from the detection processing unit 122 and receives the corrected header data D2'_head from the synchronization processing unit 121. When the estimation processing unit 123 determines that the header data corresponding to the signal Sig_IQ exists, it derives the source u of the signal Sig_IQ from the header data corresponding to the signal Sig_IQ. z After that, the estimation processing unit 123 performs an average phase characteristic extraction process on the signal Sig_IQ when the signal Sig_IQ contains the corresponding header data, by a method to be described later, to obtain the starting sample number s of the signal Sig_IQ. j and the average phase characteristic m j Then, the estimation processing unit 123 acquires the source u z The FIFO memory associated with the same source as j and the average phase characteristic m j and characteristic value C j Execute the save process to save the data.

[0072] On the other hand, when it is determined that the header data corresponding to the signal Sig_IQ does not exist, the estimation processing unit 123 performs the process of estimating the source based on the signal Sig_IQ when the header data corresponding to the signal Sig_IQ does not exist, and j and the average phase characteristic m j " characteristic value C Sig_IQ The characteristic value C closest to j Source u with Sig_IQ is detected from the transmission sources u1, u2, . . . stored in the storage unit 124, and the detected transmission source u Sig_IQ is performed as the source of the signal Sig_IQ.

[0073] The storage unit 124 includes transmission sources u1, u2, . . . and a FIFO memory 1, a FIFO memory 2, . . . Each of the FIFO memory 1, the FIFO memory 2, . . . is realized by a FIFO (First In First Out) memory.

[0074] The FIFO memory 1, FIFO memory 2, etc. are associated with the transmission sources u1, u2, etc., respectively. The FIFO memory 1 stores the MAC address MAC1 and the characteristic value C of the sample data. 1_1 ,C 2_1 ,···,C N_1 N is the maximum number of characteristic values n that can be stored in each of the FIFO memories 1, 2, etc. fifo Characteristic value C 1_1 ,C 2_1 ,···,C N_1 Each of these is the starting sample number s of the preamble of the header data, which will be described later. j and the average phase characteristic m j It consists of:

[0075] FIFO memory 2 stores MAC address MAC2 and characteristic value C of the sample data. 1_2 ,C 2_2 ,···,C N_2 Characteristic value C is stored. 1_2 ,C 2_2 ,···,C N_2 Each of these is the starting sample number s of the preamble of the header data, which will be described later. j and the average phase characteristic m j It consists of:

[0076] Characteristic value C 1_1 ,C 2_1 ,···,C N_1 The "1" in each of these is the argument corresponding to the "1" of the sender u1. 1_2 ,C 2_2 ,···,C N_2 The "2" in each of these is an argument corresponding to the "2" of the sender u2.

[0077] And, [Source u1 / MAC1 / C 1_1 ,C 2_1 ,···,C N_1 ],[Source u2 / MAC2 / C 1_2 ,C 2_2 ,···,C N_2 ],... are stored in advance in the storage unit 124 based on a set of successfully decoded frames.

[0078] Fig. 4 is a schematic diagram showing the configuration of synchronization processing unit 121 shown in Fig. 3. Referring to Fig. 4, synchronization processing unit 121 includes a first FIFO memory 1211, a second FIFO memory 1212, an offset acquisition processing unit 1213, an offset value holding unit 1214, and a correction header data acquisition unit 1215.

[0079] The first FIFO memory 1211 is realized using, for example, a FIFO memory. The first FIFO memory 1211 functions as a buffer that receives the synchronization detection data D1_p output from the third communication interface 11 and stores and holds the received data. Specifically, the first FIFO memory 1211 sequentially receives (inputs in chronological order) sample data of the synchronization detection data D1_p output from the third communication interface 11 and stores and holds a predetermined number of sample data. Any sample data stored in the first FIFO memory 1211 can be read by the offset acquisition processing unit 1213.

[0080] The second FIFO memory 1212 is realized using, for example, a FIFO memory. The second FIFO memory 1212 functions as a buffer that receives the header data D2_head output from the third communication interface 11 and stores and holds the received data. Specifically, the second FIFO memory 1212 sequentially receives (inputs in chronological order) sample data of the header data D2_head output from the third communication interface 11 and stores and holds a predetermined number of sample data. Any sample data stored in the second FIFO memory 1212 can be read by the offset acquisition processing unit 1213.

[0081] The offset acquisition processing unit 1213 can read out any sample data at any timing from the first FIFO memory 1211 and / or the second FIFO memory 1212. The offset acquisition processing unit 1213 then executes an offset calculation process using the sample data of the synchronization detection data D1_p read out from the first FIFO memory 1211 and the sample data of the header data D2_head read out from the second FIFO memory 1212, and obtains an offset value e opt Then, the offset acquisition processing unit 1213 calculates the calculated offset value e opt The data including the above is output to the offset value holding unit 1214 as data D_offset.

[0082] The offset value holding unit 1214 stores the output offset value e out When data D_offset is input from the offset acquisition processing unit 1213, the offset value storage unit 1214 stores and holds the offset value e opt and obtain the offset value e opt The output offset value e out (updates the output offset value).

[0083] The offset value storage unit 1214 stores and stores the output offset value e out to the correction header data acquisition unit 1215.

[0084] The correction header data acquisition unit 1215 acquires the header data D2_head output from the third communication interface 11 and the output offset value e output from the offset value holding unit 1214. out Each time the header data D2_head is input, the corrected header data acquisition unit 1215 calculates an output offset value e outThe corrected header data acquisition unit 1215 then performs a correction process (adjustment process) on the timestamp of the header data according to the above, and acquires corrected header data D2'_head with the corrected timestamp. Then, the corrected header data acquisition unit 1215 outputs the acquired corrected header data D2'_head to the estimation processing unit 123.

[0085] FIG. 5 is a diagram for explaining a graphical representation of envelope data. Referring to FIG. 5, the envelope data acquisition unit 25 of the sensor device 20 acquires data (envelope data D1_env) relating to the signal strength of the received wireless signal Sig0 (for example, the signal Sig0 in the upper diagram of FIG. 5) as data expressed in a rectangle (rectangular data (for example, data D1_env in FIG. 5)), for example, as shown in FIG. 5. If the values of the I component and the Q component of one IQ sample (corresponding to one sample data of the signal Sig) are I and Q, respectively, the envelope data acquisition unit 25 calculates the signal strength S of the IQ sample as S=10×log10(I 2 +Q 2 ) is obtained.

[0086] The "rectangle data" may be any data that specifies a rectangle, such as (1) data including a start time, an end time, and a Y-axis value (in the case of FIG. 5, a value corresponding to the signal strength value), or (2) data including a start time, a duration, and a Y-axis value (in the case of FIG. 5, a value corresponding to the signal strength value). Therefore, the envelope data D1_env consists of rectangle data having a duration, as shown in FIG. 5.

[0087] Then, the envelope data acquisition unit 25 outputs the acquired data D1_env to the first communication interface 27.

[0088] The synchronization detection data generator 26 of the sensor device 20 performs synchronization detection data generation processing on the data D1_IQ output from the IQ data acquirer 24, and generates synchronization detection data D1_p (time-series data including only timestamps as attributes).

[0089] 6 is a diagram for explaining the synchronization detection data generation process. Note that FIG. 6 shows sample data d of the data D1_IQ output from the IQ data acquisition unit 24. i (i is an integer greater than or equal to 0) i This is an example diagram showing .rss in chronological order.

[0090] In the synchronization detection data generation process, the synchronization detection data generation unit 26 generates sample data d i Signal strength d i .rss to the sample data D1_IQ i The values of the I and Q components of i .I and d i .Q, it can be obtained by the following formula.

[0091]

number

[0092] Then, the synchronization detection data generating unit 26 generates the sample data d of the data D1_IQ acquired at the current time. i Signal strength d i .rss is compared with a predetermined threshold rss_th, and the sample data d of the data D1_IQ acquired at the time one sample before the current time is i-1 Signal strength d i-1 .rss is compared with a predetermined threshold rss_th.

[0093] As a result of the above comparison, d i-1 .rss <rss_thであり、かつ d i .rss≧rss_th If so, the synchronization detection data generating unit 26 generates the sample data d of the data D1_IQ acquired at the current time. i timestamp d i Get .ts and the obtained timestamp d i .ts to the sample data p of the synchronous detection data D1_p jtimestamp p j .ts to generate synchronization detection data D1_p (see FIG. 6).

[0094] [IQ Data] The IQ data is data obtained by down-converting the frequency of a received signal when a radio frame is received. The IQ data is made up of a plurality of samples. Each of the plurality of samples is made up of an I component and a Q component. In the IQ data, a sample d having a sample number i (i is an integer equal to or greater than 0) is i The values of the I and Q components of i .I,d i .Q, then sample d i Signal strength d i .rss is calculated using formula (1).

[0095] Sample d i timestamp d i .ts is the timestamp at which the AD converter starts sampling. start and the sampling period is F s Then, it is expressed by the following equation.

[0096]

number

[0097] [Header data] The header data is a time series of extracted information stored in the header portion of each frame obtained by decoding the demodulated bit string based on the specifications (specifications: information indicating what each part of the demodulated bit string represents) of the target wireless system (IEEE802.11a, IEEE802.11g, etc.).

[0098] The main information that can be obtained by extracting (analyzing) the header part is as follows:

[0099] Frame duration Source MAC address (MAC: Media Access Control) Destination MAC address Frame type (Beacon, Data, Ack, etc.) Fig. 7 is a conceptual diagram showing the duration and type of a frame. In Fig. 7, the vertical axis represents the presence or absence of data (1 or 0). Referring to Fig. 7, the types of frames are Data, Ack, and Beacon.

[0100] Data is a bit string representing the information transmitted by the frame. Ack is an acknowledgement, a signal, data, packet, etc. sent when returning some kind of affirmative response to the other party in communication between two parties. Beacon is a control frame for transmitting various control information.

[0101] For each of Data, Ack, and Beacon, the left end is the start point, and the horizontal length is the duration.

[0102] Each data in the header data is assigned a timestamp indicating the start time of the corresponding frame (see FIG. 5).

[0103] The offset acquisition process executed in the synchronization processing unit 121 shown in FIG. 3 will be described.

[0104] 8 is a flowchart illustrating the offset acquisition process. The offset acquisition process is executed, for example, at a predetermined cycle T (for example, T=10 seconds).

[0105] 8, the offset acquisition processing unit 1213 determines whether or not both the first FIFO 1211 (FIFO for synchronization detection data) and the second FIFO 1212 (FIFO for header data) hold n_fifo pieces of data (step S1).

[0106] In step S1, when it is determined that both the first FIFO 1211 and the second FIFO 1212 hold n_fifo pieces of data, the offset value holding unit 1214 executes data acquisition selection processing (step S2), executes offset calculation processing (step S3), and executes offset update processing (step S4).

[0107] And in step S1, when it is determined that both the first FIFO 1211 and the second FIFO 1212 do not hold n_fifo pieces of data, or after step S4, the offset acquisition processing ends.

[0108] FIG. 9 is a flowchart for explaining the detailed operation of step S2 in FIG. 8.

[0109] Referring to FIG. 9, in step S1 of FIG. 8, when it is determined that both the first FIFO 1211 and the second FIFO 1212 hold n_fifo pieces of data, the offset value holding unit 1214 reads n_fifo pieces of data from the first FIFO 1211 as synchronization detection data p i (i: integer, 0 ≦ i < n_fifo) (step S201). Note that the acquired n_fifo pieces of synchronization detection data p i are sorted in ascending order of the time stamp value p i .ts. Also, the set data of the sample data p i of the synchronization detection data is denoted as {p i}.

[0110] Then, the offset value holding unit 1214 reads n_fifo pieces of data from the second FIFO 1212 as header data s i (i: integer, 0 ≦ i < n_fifo) (step S202). Note that the acquired n_fifo pieces of header data s i are sorted in ascending order of the time stamp value s i .ts. Also, the set data of the sample data s i of the header data is denoted as {s i}.

[0111] After that, the offset value holding unit 1214 selects n_hdr pieces of data from the n_fifo pieces of header data s acquired in step S202, and sets the selected n_hdr pieces of data as ss i (where i is an integer, 0 ≤ i < n_hdr) (step S203). Note that the set data of the sample data ss i of the selected header data is denoted as {ss i}. i

[0112] After step S203, the series of operations proceeds to step S3 in FIG. 8.

[0113] FIG. 10 and FIG. 11 are the first and second flowcharts for explaining the detailed operations of step S3 in FIG. 8, respectively.

[0114] Referring to FIG. 10, after executing step S2 (selection process), the offset acquisition processing unit 1213 initializes the set P for the time stamp p i of the sample data p of the synchronization detection data (sets the set P as an empty set φ), and initializes the set E for the offset value e (sets the set E as an empty set φ) (step S301). i .ts (sets the set E as an empty set φ) (step S301).

[0115] Then, the offset acquisition processing unit 1213 sets i = 0 (step S302). After that, the offset acquisition processing unit 1213 reads the time stamp p i of the sample data p of the synchronization detection data from the first FIFO 1211, and adds the time stamp p i .ts to the set P (step S303). That is, the offset acquisition processing unit 1213 i .ts to the set P (step S303). That is, the offset acquisition processing unit 1213 executes the process corresponding to P←P∪{p i .ts} .

[0116] ​After that, the offset acquisition processing unit 1213 sets j=0 (step S304). e=p i .ts-ss j .ts p i .ts:Sample data for synchronization detection p i The timestamp value of ss j .ts: Sample data of header data selected by selection process ss i The timestamp value of and calculates an offset value e (a candidate for the offset value) (step S305).

[0117] Then, the offset acquisition processing unit 1213 adds the calculated offset value e (offset value candidate) to the set E. That is, the offset acquisition processing unit 1213 adds the calculated offset value e (offset value candidate) to the set E. E←E∪{e} (step S306).

[0118] The offset acquisition processing unit 1213 determines whether j=n_hdr-1 holds (step S307).

[0119] If it is determined in step S307 that j is not equal to n_hdr-1, the offset acquisition processing unit 1213 sets j to j+1 (step S308). Then, the series of operations proceeds to step S305. Thereafter, steps S305 to S308 are repeatedly executed until it is determined in step S307 that j is equal to n_hdr-1.

[0120] Then, if it is determined in step S307 that j=n_hdr-1, the offset acquisition processing unit 1213 determines whether i=n_fifo-1 (step S309).

[0121] If it is determined in step S309 that i is not equal to n_fifo-1, the offset acquisition processing unit 1213 sets i to i+1 (step S310). Then, the series of operations proceeds to step S303. Thereafter, steps S303 to S310 are repeatedly executed until it is determined in step S309 that i is equal to n_fifo-1.

[0122] If it is determined in step S309 that i=n_fifo−1, the series of operations proceeds to step S311 in FIG.

[0123] 11, if it is determined in step S309 of FIG. 10 that i=n_fifo-1, the offset acquisition processing unit 1213 sets the variable c max and the variable e opt Initialization process (c max =0, e opt =0) (step S311).

[0124] Thereafter, the offset acquisition processing unit 1213 sets v=1 (step S312). Note that v is an argument of the offset value e included in the set E, and v=1 to v max (=n_Sfifo×n_hdr).

[0125] After step S312, the offset acquisition processing unit 1213 performs initialization processing of the variable c (c=0) (step S313).

[0126] Then, the offset acquisition processing unit 1213 sets i=0 (step S314) and i .ts+e v Calculate the value of (ss i .ts+e v It is determined whether the value of (value of) is included in the set P (step S315).

[0127] In step S315, ss i .ts+e vIf it is determined that the value of c is included in the set P, the offset acquisition processing unit 1213 sets c=c+1 (that is, increments the value of the variable c by "1") (step S316).

[0128] Then, in step S315, ss i .ts+e v When it is determined that the value of is not included in the sum P, or after step S316, the offset acquisition processing unit 1213 determines whether i=n_hdr-1 (step S317).

[0129] If it is determined in step S317 that i is not equal to n_hdr-1, the offset acquisition processing unit 1213 sets i to i+1 (step S318). Then, the series of operations proceeds to step S315. Thereafter, steps S315 to S318 are repeatedly executed until it is determined in step S317 that i is equal to n_hdr-1.

[0130] Then, in step S317, if it is determined that i=n_hdr−1, the offset acquisition processing unit 1213 determines whether c>c max It is determined whether or not (step S319). In step S319, c>c max When it is determined that c=c max and e=e opt is set (step S320).

[0131] Then, in step S319, c>c max If it is determined that v is not equal to v, or after step S320, the offset acquisition processing unit 1213 max It is determined whether or not (=n_fifo×n_hdr) (step S321).

[0132] In step S321, v=v maxIf it is determined that v is not the offset, the offset acquisition processing unit 1213 sets v=v+1 (step S322). Then, the series of operations proceeds to step S313. After that, in step S321, v=v max Steps S313 to S322 are repeatedly executed until it is determined that the above condition is met.

[0133] Then, in step S321, v=v max If it is determined that the above is the case, the series of operations proceeds to step S4 in FIG.

[0134] Note that v in step S321 of FIG. max ga v max The reason for n_fifo × n_hdr is as follows:

[0135] The loop of steps S305 → S306 → S307 "NO" → S308 → S305 in FIG. 10 is executed n_hdr times (j = 0 to n_hdr-1), and the loop of steps S303 → S304 → S305 → S306 → S307 "YES" → S309 "NO" → S310 → S303 in FIG. 10 is executed n_fifo times (i = 0 to n_fifo-1). Therefore, the number of offset value candidates calculated in step S305 is n_hdr × n_fifo, and the loop of steps S313 → S314 → ... → S317 "YES" → S319 "YES" → S320 → S321 "NO" → step S322 → S313 in FIG. 11 is executed for n_hdr × n_fifo offset value candidates e.

[0136] FIG. 12 is a flowchart for explaining the detailed operation of step S4 in FIG.

[0137] 12, after step S3 in FIG. 8, the offset acquisition processing unit 1213 max It is determined whether or not is equal to or greater than a predetermined threshold value c_th (step S401).

[0138] In step S401, c maxis determined to be equal to or greater than the predetermined threshold c_th, the offset acquisition processing unit 1213 calculates the offset value e opt to the offset value holding unit 1214. The offset value holding unit 1214 receives the offset value e opt When you enter the value, the stored output offset value e out (Initial value is 0) offset value e opt (i.e., offset value e opt (Step S402).

[0139] Then, in step S401, max When it is determined that is not equal to or greater than the predetermined threshold value c_th, or after step S402, the series of operations proceeds to "END" in FIG.

[0140] As described above, the offset acquisition process is performed by the synchronization processing unit 121. Then, the offset value holding unit 1214 of the synchronization processing unit 121 stores and holds the output offset value e out to the correction header data acquisition unit 1215.

[0141] The correction header data acquisition unit 1215 acquires the header data D2_head output from the third communication interface 11 and the output offset value e output from the offset value holding unit 1214. out Then, every time the header data D2_head is input, the corrected header data acquisition unit 1215 calculates the output offset value e out Specifically, the corrected header data acquisition unit 1215 performs a correction process (adjustment process) of the timestamp of the header data by s i '.ts=s i .ts+e out The sample data s of the header data D2_head is i timestamp s i .ts to output offset value e outCorrect the value by adding the sample data s of the header data D2'_head i Timestamp of 's i Let's say '.ts'.

[0142] The corrected header data D2′_head thus acquired is output from the corrected header data acquisition unit 1215 to the estimation processing unit 123.

[0143] 13 is a diagram for explaining the signal detection process. Referring to FIG. 13, (a) shows the relationship between the signal strength of the IQ data and time, and (b) shows the relationship between the signal detection result and time. In FIG. 13(a), each rectangular shape indicates the signal strength of one sample of the IQ data.

[0144] The detection processing unit 122 receives the envelope data D1_env from the third communication interface 11. The envelope data D1_env is IQ data because it is acquired from the data D1_IQ by the envelope data acquisition unit 25 of the sensor device 20. Therefore, in FIG. 8(a), it is written as "IQ data (=D1_env)". Also, the variable b is initialized to "0". The variable b is then calculated based on the threshold value r thresh Signal strength of d or more i Sample d of IQ data (=D1_env) with .rss i The threshold r is a variable that indicates whether or not thresh Signal strength of d or more i Sample d of IQ data (=D1_env) with .rss i When does not exist, b is b=0 and the threshold r thresh Signal strength of d or more i Sample d of IQ data (=D1_env) with .rss i exists, then b=1.

[0145] When the detection processing unit 122 receives the IQ data (=D1_env) from the third communication interface 11, the detection processing unit 122 detects whether the signal strength d0.rss of the sample d0 of the IQ data (=D1_env) is equal to or exceeds the threshold r threshand the start time of sample d0 is set to the start time t start The threshold value r thresh is, for example, -60 dBm.

[0146] Next, the detection processing unit 122 detects whether the signal strength d1.rss of the sample d1 of the IQ data (=D1_env) is greater than or equal to the threshold r thresh If it is determined that b is not equal to or greater than 0, it is determined that b=0, and the start time of sample d1 is set to the start time t start Do not set to .

[0147] Thereafter, the detection processing unit 122 detects whether the signal strength d2.rss of the sample d2 of the IQ data (=D1_env) is greater than or equal to the threshold r thresh It is determined that b=0, the value of variable b is set to "1", and the start time of sample d2 is set to the start time t start Set to.

[0148] Subsequently, the detection processing unit 122 detects whether the signal strength d3.rss of the sample d3 of the IQ data (=D1_env) is equal to or exceeds the threshold r thresh It is determined that b is not 0, and the target of signal detection processing (sample d of IQ data (= D1_env) i ) is sample d4 of the IQ data (=D1_env).

[0149] Then, the detection processing unit 122 detects whether the signal strength d4.rss of the sample d4 of the IQ data (=D1_env) is greater than or equal to the threshold r thresh It is determined that b is not 0, and the target of signal detection processing (sample d of IQ data (= D1_env) i ) is sample d5 of the IQ data (=D1_env).

[0150] Thereafter, the detection processing unit 122 detects whether the signal strength d5.rss of the sample d5 of the IQ data (=D1_env) is greater than or equal to the threshold r thresh It is determined that b is not 0, and the target of signal detection processing (sample d of IQ data (= D1_env) i) is sample d6 of the IQ data (=D1_env).

[0151] Subsequently, the detection processing unit 122 detects whether the signal strength d6.rss of the sample d6 of the IQ data (=D1_env) is equal to or exceeds the threshold r thresh It is determined that b is not 0, and the target of signal detection processing (sample d of IQ data (= D1_env) i ) is sample d7 of the IQ data (=D1_env).

[0152] Then, the detection processing unit 122 detects whether the signal strength d7.rss of the sample d7 of the IQ data (=D1_env) is greater than or equal to the threshold r thresh It is determined that b is not 0, and the target of signal detection processing (sample d of IQ data (= D1_env) i ) is sample d8 of the IQ data (=D1_env).

[0153] Thereafter, the detection processing unit 122 detects whether the signal strength d8.rss of the sample d8 of the IQ data (=D1_env) is greater than or equal to the threshold r thresh It is determined that the signal duration is not d8.ts-t start d8.ts is the start point of sample d8 of the IQ data (=D1_env) (i.e., the end point of sample d7).

[0154] The detection processing unit 122 detects the duration of the signal d8.ts-t start Calculating the signal duration d8.ts-t start is the threshold t thresh At the signal start time t start (=d2.ts) and signal duration d8.ts-t start The output is the threshold t thresh is, for example, 20 μs.

[0155] Thereafter, the detection processing unit 122 initializes the variable b (b=0) and start Initialize (t start =0). In addition, the detection processing unit 122 sets the sample di The argument i is also initialized (i=0).

[0156] Then, the detection processing unit 122 detects whether the signal strength d0.rss of the sample d0 next to the sample d8 is greater than or equal to the threshold r thresh If it is determined that b is not equal to or greater than 0, it is determined that b=0, and the target of signal detection processing (sample d of IQ data (=D1_env) i ) is sample d1 of the IQ data (=D1_env).

[0157] Thereafter, the detection processing unit 122 detects whether the signal strength d1.rss of the sample d1 is greater than or equal to the threshold r thresh If it is determined that b is not equal to or greater than 0, it is determined that b=0, and the target of signal detection processing (sample d of IQ data (=D1_env) i ) is sample d2 of the IQ data (=D1_env).

[0158] Subsequently, the detection processing unit 122 detects whether the signal strength d2.rss of the sample d2 is equal to or greater than the threshold r thresh If it is determined that b is not equal to or greater than 0, it is determined that b=0, and the target of signal detection processing (sample d of IQ data (=D1_env) i ) is sample d3 of the IQ data (=D1_env).

[0159] Then, the detection processing unit 122 detects whether the signal strength d3.rss of the sample d3 is greater than or equal to the threshold r thresh It is determined that b=0, the value of variable b is set to "1", and the start time of sample d3 is set to the start time t start Set to.

[0160] Thereafter, the detection processing unit 122 detects whether the signal strength d4.rss of the sample d4 is greater than or equal to the threshold r thresh It is determined that b is not 0, and the target of signal detection processing (sample d of IQ data (= D1_env) i ) is sample d5 of the IQ data (=D1_env).

[0161] Subsequently, the detection processing unit 122 detects whether the signal strength d5.rss of the sample d5 is equal to or greater than the threshold rthresh It is determined that the time is not greater than or equal to d5.ts-t. start Calculate the duration d5.ts-t start is the threshold t thresh It is determined that it is not greater than or equal to this.

[0162] Thereafter, the detection processing unit 122 initializes the variable b (b=0) and start Initialize (t start =0). In addition, the detection processing unit 122 sets the sample d i The argument i is also initialized (i=0).

[0163] Then, the detection processing unit 122 detects samples d0 to d 10 For each of the signals, the signal strength d0.rss~d 10 .rss is the threshold r thresh It is determined that it is not equal to or greater than this, and it is determined that b=0.

[0164] Next, the detection processing unit 122 detects the sample d 11 Signal strength d 11 .rss is the threshold r thresh If it is determined that b=0, the value of variable b is set to "1" and sample d is 11 The start time of the signal is t start Set to.

[0165] Then, the detection processing unit 122 detects the sample d 12 ~d 16 For each of the signal strength d 12 .rss~d 16 .rss is the threshold r thresh It is determined that it is equal to or greater than b, and it is determined that b is not 0.

[0166] Subsequently, the detection processing unit 122 detects the sample d 17 Signal strength d 17 .rss is the threshold r thresh It is determined that the time is not greater than or equal to b, and b is not 0. 17 .ts-t start Calculate the duration d17 .ts-t start is the threshold t thresh At the signal start time t start (=d 11 .ts) and signal duration d 17 .ts-t start and is output.

[0167] When the detection processing unit 122 receives the IQ data (=D1_env) from the third communication interface 11, the detection processing unit 122 performs the above-described operation to extract a signal (signal start time t start and duration d i .ts-t start ) and detects the detected signal (signal start time t start and duration d i .ts-t start ) to the estimation processing unit 123.

[0168] 14 is a diagram showing the flow of processing in the transmission source estimation unit 12 shown in FIGS. 2 and 3. Referring to FIG. 14, when the detection processing unit 122 receives the IQ data (D1_env) from the third communication interface 11, it executes the signal detection processing described in FIG. 13 and outputs the detected signal Sig_IQ to the estimation processing unit 123. The signal Sig_IQ is detected at a signal start time t start and duration d i .ts-t start Includes:

[0169] The estimation processing unit 123 receives the corrected header data D2′_head from the third communication interface 11 and receives the detected signal Sig_IQ from the detection processing unit 122.

[0170] Then, the estimation processing unit 123 executes a process of determining whether or not header data corresponding to the signal Sig_IQ detected by the signal detection process exists.

[0171] When the estimation processing unit 123 determines in the determination processing that the signal Sig_IQ detected by the signal detection processing contains the corresponding header data, it performs an average phase characteristic extraction processing on the signal Sig_IQ when the corresponding header data is present in the signal Sig_IQ, and extracts the characteristic values (start sample number and average phase characteristic) of the source. This characteristic value is a characteristic value specific to the transmission path between the transmitter and receiver of the wireless frame.

[0172] Then, the estimation processing unit 123 stores the extracted characteristic values (start sample number and average phase characteristic) in a FIFO associated with each transmission source. After that, the processing in the transmission source estimation unit 12 proceeds to signal detection processing.

[0173] On the other hand, when the estimation processing unit 123 determines in the judgment processing that there is no header data corresponding to the signal Sig_IQ detected by the signal detection processing, it refers to the ``FIFO associated with each source'' stored in the memory unit 124 and performs a source estimation processing to estimate the source of the signal Sig_IQ based on the signal Sig_IQ when there is no header data corresponding to the signal Sig_IQ, and estimates the source of the signal Sig_IQ.

[0174] In this case, the estimation processing unit 123 executes the average phase characteristic extraction process based on the signal Sig_IQ when the corresponding header data does not exist in the signal Sig_IQ, and calculates the starting sample number s of the sample of the signal Sig_IQ. j1 and the average phase characteristic m j1 Then, the estimation processing unit 123 extracts the characteristic values (start sample number s j1 and the average phase characteristic m j1 ) closest to the characteristic value (starting sample number s j0 and the average phase characteristic m j0 ) is estimated as the source of the signal Sig_IQ.

[0175] After the transmission source estimation process, the process in the transmission source estimation unit 12 proceeds to the signal detection process.

[0176] Therefore, every time the transmission source estimation unit 12 receives the IQ data (D1_env) from the third communication interface 11, it executes the processing flow shown in FIG.

[0177] FIG. 15 is a diagram for explaining a method for determining whether or not header data corresponding to the signal Sig_IQ detected in the signal detection process exists.

[0178] 15, the signal Sig_IQ_1 and the header data D_head_1 are synchronized by a synchronization processing unit 121, and the signal Sig_IQ_2 and the header data D_head_2 are synchronized by a synchronization processing unit 121.

[0179] However, more particularly, the signal Sig_IQ_1 and the header data D_head_1 are offset in time from one another, and the signal Sig_IQ_2 and the header data D_head_2 are also offset in time from one another.

[0180] The difference between the start point of the signal Sig_IQ_1 detected in the signal detection process and the start point of the header data D_head_1 is w0, and the difference between the end point of the signal Sig_IQ_1 and the end point of the header data D_head_1 is w1. As described above, each data in the header data is assigned a timestamp indicating the start point of the corresponding frame (see FIG. 5). start and signal duration d i .ts-t start is output from the detection processing unit 122 to the estimation processing unit 123, so that the estimation processing unit 123 can calculate the differences w0 and w1.

[0181] As a result, the signal Sig_IQ_1 and the header data D_head_1 overlap with each other for an overlap time t_over_1.

[0182] Therefore, the sum of the time periods w0 and w1 (=non-overlap time) between the signal Sig_IQ_1 and the header data D_head_1 is equal to the threshold value w thresh (e.g., w thresh = 50 μs.), the estimation processing unit 123 regards the header data D_head_1 as header data corresponding to the detected signal Sig_IQ_1. That is, the estimation processing unit 123 determines that header data corresponding to the detected signal Sig_IQ_1 exists.

[0183] On the other hand, the difference between the start point of signal Sig_IQ_2 detected in the signal detection process and the start point of header data D_head_2 is w0, and the difference between the end point of signal Sig_IQ_2 and the end point of header data D_head_2 is w1. For signal Sig_IQ_2 and header data D_head_2, estimation processing unit 123 can calculate the differences w0 and w1 in the same way as for signal Sig_IQ_1 and header data D_head_1 described above.

[0184] As a result, the signal Sig_IQ_2 and the header data D_head_2 overlap with each other over an overlap time t_over_2.

[0185] Therefore, the sum of the time periods w0 and w1 (=non-overlap time) between the signal Sig_IQ_2 and the header data D_head_2 is equal to the threshold value w thresh , the estimation processor 123 does not regard the header data D_head_2 as header data corresponding to the detected signal Sig_IQ_2, i.e., determines that there is no header data corresponding to the detected signal Sig_IQ_2.

[0186] In this way, a slight timestamp difference between the IQ data and the header data (i.e., the threshold w thresh The header data corresponding to the detected signal Sig_IQ is identified while allowing for the following deviation.

[0187] The durations of the signals Sig_IQ_1 and Sig_IQ_2 are acquired by the detection processing unit 122 and output to the estimation processing unit 123, as described with reference to FIG.

[0188] Each of the header data D_head_1 and D_head_2 (consisting of D2'_head shown in FIG. 3) has a time stamp s corrected to synchronize with the IQ data as shown in FIG. i '.ts(=s i .ts+e out ) to the estimation processing unit 123. Since each of the header data D_head_1 and D_head_2 is time-series data, the estimation processing unit 123 outputs the corrected time stamp s i '.ts(=s i .ts+e out ) is received, the corrected timestamp s i '.ts(=s i .ts+e out ) as the start point of each of the header data D_head_1 and D_head_2, the duration of each of the header data D_head_1 and D_head_2 can be detected.

[0189] Therefore, the estimation processing unit 123 can determine whether or not the detected signal Sig_IQ contains corresponding header data by the method described with reference to FIG.

[0190] FIG. 16 is a flowchart for explaining the operations of the detection processing unit 122 and the estimation processing unit 123 shown in FIG.

[0191] Referring to FIG. 16, when the operations of detection processing unit 122 and estimation processing unit 123 start, detection processing unit 122 executes a signal detection process (step S11).

[0192] Then, the estimation processing unit 123 determines whether or not a signal has been detected (step S12). In this case, when the estimation processing unit 123 receives the signal Sig_IQ detected in the signal detection processing from the detection processing unit 122, the estimation processing unit 123 determines that a signal has been detected, and when the estimation processing unit 123 does not receive the signal Sig_IQ detected in the signal detection processing from the detection processing unit 122, the estimation processing unit 123 determines that a signal has not been detected.

[0193] When it is determined in step S12 that a signal has been detected, the estimation processing unit 123 determines whether or not header data corresponding to the detected signal Sig_IQ exists (step S13). In this case, the estimation processing unit 123 determines whether the sum of the time periods of the non-overlapping regions of the signal Sig_IQ and the header data, w0+w1, is equal to or greater than the threshold w thresh If the sum of the time periods of the non-overlapping regions of the signal Sig_IQ and the header data, w0+w1, is less than or equal to the threshold w thresh If the detected signal Sig_IQ is longer than 1, it is determined that the corresponding header data does not exist in the detected signal Sig_IQ.

[0194] In step S13, when it is determined that the header data corresponding to the detected signal Sig_IQ exists, the estimation processing unit 123 derives the signal transmission source u from the header data corresponding to the detected signal Sig_IQ. z is obtained (step S14).

[0195] As described above, the header data includes the MAC address of the sender, so the estimation processing unit 123 determines the sender u of the signal from the header data. z can be obtained.

[0196] After step S14, the estimation processing unit 123 executes an average phase characteristic extraction process on the signal Sig_IQ when the signal Sig_IQ contains the corresponding header data (step S15).

[0197] Then, the estimation processing unit 123 determines whether or not the first sample number of the preamble has been identified for the signal Sig_IQ when the signal Sig_IQ contains the corresponding header data (step S16). In this case, the estimation processing unit 123 determines whether or not the first sample number of the preamble has been identified for the detected signal Sig_IQ by the method described in Non-Patent Document 2.

[0198] In step S16, when it is determined that the first sample number of the preamble has been identified for the detected signal Sig_IQ, the estimation processing unit 123 determines whether the source u z The starting sample number s obtained in the "average phase characteristic extraction process" is used for the FIFO memory for j and the average phase characteristic m j Here, the starting sample number s obtained in the "average phase characteristic extraction process" is stored (step S17). j and the average phase characteristic m j is a characteristic value specific to the transmission path between the transmitter and receiver of the frame. And, this average phase characteristic m j is the source u z It is obtained by using the frequency response of the propagation path along which the frame transmitted from

[0199] On the other hand, when it is determined in step S13 that the detected signal Sig_IQ does not contain any corresponding header data, the estimation processing unit 123 executes a source estimation process (step S18).

[0200] Then, when it is determined in step S12 that no signal has been detected, or when it is determined in step S16 that the first sample number of the preamble has not been identified for the detected signal Sig_IQ, or after step S17, or after step S18, the operation of the detection processing unit 122 and the estimation processing unit 123 proceeds to step S11.

[0201] The flowchart shown in FIG. 16 is executed every time the IQ data (D1_env) is input to the detection processing unit 122.

[0202] In the flowchart shown in FIG. 16, in step S14, the estimation processing unit 123 determines the signal transmission source u from the header data corresponding to the detected signal Sig_IQ. z After obtaining the above, in step S15, the signal Sig_IQ (= the signal detected by the detection processing unit 122) when the corresponding header data exists in the signal Sig_IQ is analyzed (i.e., the average phase characteristic extraction process is executed) to obtain the start sample number s, which is a characteristic value specific to the transmission path between the transmitter and receiver of the frame. j and the average phase characteristic m j Get.

[0203] In the flowchart shown in FIG. 16, the source u acquired in step S14 z is not stored in the storage unit 124, the estimation processing unit 123 performs step S17 to z is stored in the storage unit 124, and the stored source u z FIFO memory is newly created in association with the start sample number s obtained in the average phase characteristic extraction process in step S15. j and the average phase characteristic m j The characteristic value C consists of j is stored in the newly created FIFO memory.

[0204] FIG. 17 is a flowchart for explaining the signal detection process in step S11 of FIG.

[0205] 17, from "START" in FIG. 16, or when it is determined in step S12 that no signal is detected, or when it is determined in step S16 that the leading sample number of the preamble has not been identified for the detected signal Sig_IQ, or after step S17, or after step S18, the detection processing unit 122 sets b=0 and ts=0 to the variables b and t start (Step S111). Here, the variable t start is the signal strength di .rss first reaches the threshold r thresh Sample d that was more than i timestamp d i A variable indicating .ts.

[0206] After step S111, the detection processing unit 122 sets i=0 (step S112), where i is the number of samples d of the signal Sig_IQ. i are the arguments of, where i=0,1,2,...

[0207] Then, the detection processing unit 122 detects the sample d i Signal strength d i .rss is the threshold r thresh It is determined whether or not it is equal to or greater than this (step S113).

[0208] In step S113, sample d i Signal strength d i .rss is the threshold r thresh If it is determined that this is the case, the detection processing unit 122 determines whether b=0 (step S114).

[0209] In step S114, when it is determined that b=0, the detection processing unit 122 sets b=1 and t start =d i .ts is set (step S115).

[0210] Then, when it is determined in step S114 that b is not 0, or after step S115, the series of operations proceeds to step S117.

[0211] On the other hand, in step S113, sample d i Signal strength d i .rss is the threshold r thresh If it is determined that the value is not equal to or greater than b, the detection processing unit 122 determines whether b=0 (step S116).

[0212] If it is determined in step S116 that b=0, the series of operations proceeds to step S117.

[0213] Then, when it is determined in step S114 that b is not 0, or after step S115, or when it is determined in step S116 that b is 0, the detection processing unit 122 sets i to i+1 (step S117). After that, the series of operations proceeds to step S113.

[0214] On the other hand, if it is determined in step S116 that b is not 0, the detection processing unit 122 determines whether the signal duration d i .ts-t start (step S118). Then, the detection processing unit 122 calculates the signal duration d i .ts-t start is the threshold t thresh It is determined whether or not it is equal to or greater than this (step S119).

[0215] In step S119, the signal duration d i .ts-t start is the threshold t thresh If it is determined that the signal start time t start and signal duration d i .ts-t start is output to the estimation processing unit 123 (step S120).

[0216] On the other hand, in step S119, the duration d i .ts-t start is the threshold t thresh If it is determined that the number is not equal to or greater than this, the series of operations proceeds to step S111.

[0217] The flowchart shown in FIG. 17 is executed every time the IQ data (D1_env) is input to the detection processing unit 122.

[0218] A case where the signals Sig_IQ_1 and Sig_IQ_3 shown in FIG. 13 are detected but the signal Sig_IQ_2 is not detected will be described according to the flowchart shown in FIG.

[0219] When the IQ data (D1_env) is input to the detection processing unit 122, the detection processing unit 122 initializes variables b and ts in step S111 of FIG. 17, and sets i=0 in step S112.

[0220] Then, in step S113, the detection processing unit 122 checks whether the signal strength d0.rss of the sample d0 of the IQ data (D1_env) is greater than or equal to the threshold r thresh It is determined that it is not equal to or greater than this, and in step S116 it is determined that b=0.

[0221] After that, in step S117, the detection processing unit 122 sets i=i+1=0+1=1.

[0222] Then, in step S113, the detection processing unit 122 determines whether the signal strength d1.rss of the sample d1 of the IQ data (D1_env) is greater than or equal to the threshold value r thresh It is determined that it is not equal to or greater than this, and in step S116 it is determined that b=0.

[0223] After that, in step S117, the detection processing unit 122 sets i=i+1=1+1=2.

[0224] Then, in step S113, the detection processing unit 122 determines whether the signal strength d2.rss of the sample d2 of the IQ data (D1_env) is greater than or equal to the threshold r thresh In step S114, it is determined that b=0, and in step S115, it is determined that b=1 and t start That is, the detection processing unit 122 sets the start time of the sample d2 to the signal start time t start Set to.

[0225] After that, in step S117, the detection processing unit 122 sets i=i+1=2+1=3.

[0226] Then, in step S113, the detection processing unit 122 determines whether the signal strength d3.rss of the sample d3 of the IQ data (D1_env) is greater than or equal to the threshold r thresh It is determined that this is the case, and since b=1 is set when i=2, it is determined in step S114 that b=0 is not the case, and i=i+1=3+1=4 is set in step S117.

[0227] As shown in Figure 13, all of the signal intensities d4.rss, d5.rss, d6.rss, and d7.rss of samples d4, d5, d6, and d7 of the IQ data (D1_env) for i=4, 5, 6, and 7 are below the threshold r thresh As described above, since b=1 is set, the detection processing unit 122 repeats the loop of "YES" in S113 → "NO" in S114 → S117 → S113 four times.

[0228] Then, at the time when the fourth loop is completed, i=8 is set in step S117, so the detection processing unit 122 determines in step S113 whether the signal strength d8.rss of the sample d8 of the IQ data (D1_env) is equal to or greater than the threshold r thresh Since b=1 is set, it is determined in step S116 that b=0 is not set, and in step S118, the signal duration d8.ts-t start In step S119, the signal duration d8.ts-t start is the threshold t thresh It is determined that the value is equal to or greater than the threshold.

[0229] Then, the detection processing unit 122 detects the signal start time t start (=d2.ts) and signal duration d8.ts-t start is output to the estimation processing unit 123.

[0230] In this way, the signal strength d2.rss of sample d2 of the IQ data (D1_env) is first measured within the threshold rthresh If it is determined that the signal strengths d3.rss to d7.rss of the samples d3 to d7 are equal to or greater than the threshold value r, b is set to 1 (see step S115). thresh While this is the case, b=1 is maintained. As a result, for i=3 to 7, "YES" in S113 → "NO" in S114 → S117 → S113 is repeatedly executed. In short, while maintaining b=1, i is incremented to "7", and when "YES" in S113 → "NO" in S114 → S117 is completed for i=7, the timestamp d i .ts is set to d8.ts.

[0231] Then, for i=8, "NO" in S113 → "NO" in S116 → "YES" in S118 → S119 are executed, and in step S120, the signal start time t start (=d2.ts) and signal duration d8.ts-t start (=d8.ts-d2.ts) will be output.

[0232] Note that the timestamp d8.ts indicates the start point of the sample d8, that is, the end point of the sample d7.

[0233] After the signal Sig_IQ_1 is detected, the variables b and ts are initialized (step S111), and i=0 is set (step S112).

[0234] Then, for samples d0, d1, and d2 where i=0, 1, and 2, the sequence of "NO" in S113 → "YES" in S116 → S117 → S113 is repeatedly executed. Here, for i=2, when "NO" in S113 → "YES" in S116 → S117 is executed, i=3 is set. During this time, b=0 is maintained.

[0235] Then, in step S113, the detection processing unit 122 checks whether the signal strength d3.rss of the sample d3 is greater than or equal to the threshold r thresh In step S114, it is determined that b=0, and in step S115, it is determined that b=1 and tstart Set =d3.ts.

[0236] Thereafter, in step S117, the detection processing unit 122 sets i=i+1=3+1=4, and in step S113, the detection processing unit 122 determines whether the signal strength d4.rss of the sample d4 exceeds the threshold r thresh If it is determined that this is the case, it is determined in step S114 that b is not 0, and in step S117 i=i+1=4+1=5 is set.

[0237] Subsequently, in step S113, the detection processing unit 122 checks whether the signal strength d5.rss of the sample d5 is greater than or equal to the threshold r thresh If it is determined that b is not equal to or greater than 0 in step S116, it is determined that b is not equal to 0 in step S118. start (d5.ts-d3.ts) is calculated, and in step S119, the signal duration d5.ts-t start is the threshold t thresh As a result, the detection processing unit 122 does not detect the signal Sig_IQ_2.

[0238] Thereafter, the detection processing unit 122 detects the signal duration d of the signal Sig_IQ_3 by the same operation as that of the signal Sig_IQ_1. 17 .ts-t start (=d 17 .ts-d 11 .ts) and the signal start time t start (=d 11 ts) and detects the signal duration d 17 .ts-t start (=d 17 .ts-d 11 .ts) and the signal start time t start (=d 11 .ts) to the estimation processing unit 123.

[0239] As described above, the threshold value r thresh Signal strength of d or more i Sample d with .rss i and the signal duration di .ts-t start is the threshold t thresh As described above, the signals Sig_IQ_1 and Sig_IQ_3 can be detected.

[0240] FIG. 18 is a flowchart illustrating the average phase characteristic extraction process.

[0241] Referring to Figure 18, when the average phase characteristic extraction process is performed in step S15 of Figure 16, after step S14 of Figure 16, the estimation processing unit 123 identifies the first sample number of the preamble of signal Sig_IQ for signal Sig_IQ when corresponding header data is present in signal Sig_IQ using the method described in non-patent document 2 (step S151).

[0242] Then, the estimation processing unit 123 determines whether or not the first sample number of the preamble has been identified for the signal Sig_IQ when the signal Sig_IQ contains the corresponding header data (step S152).

[0243] In step S152, when it is determined that the first sample number of the preamble has been identified for the signal Sig_IQ when the corresponding header data exists in the signal Sig_IQ, the estimation processing unit 123 determines the signal Sig_IQ when the corresponding header data exists in the signal Sig_IQ as "frame j" and sets the "start sample number" of frame j to s j (step S153).

[0244] Here, the starting sample number s j " is the sample number of the sample at the beginning of the preamble of the signal Sig_IQ. For example, s j = 100, the sample at the beginning of the preamble of frame j is the 100th sample d 100 means to match

[0245] Thereafter, the estimation processing unit 123 obtains the frequency response of each subcarrier by using the sample values of the Long Training Field (LTF) part of the preamble of the signal Sig_IQ when the corresponding header data exists in the signal Sig_IQ, which are subjected to a Fast Fourier Transform (FFT), and the value after the FFT of the LTF part in the case of no distortion (step S154). Here, the frequency response of the subcarrier k in the frame j is expressed as H j,k (k=1,2,···,52).

[0246] In step S154, the estimation processing unit 123 sets the "value after FFT of the LTF part in the case of no distortion" to the "value after FFT of the known signal", and divides the "value obtained by FFTing the sample value of the LTF part of the preamble" by the "value after FFT of the known signal" for all k=1, 2, . . . , 52, and calculates the division result as the frequency response H j,k (k=1,2,···,52).

[0247] After step S154, the estimation processing unit 123 calculates the phase characteristic ∠H j,k (k=1,2,...,52), unwrap the subcarrier k, and define the phase characteristic of the unwrapped subcarrier k as φ j,k (k=1, 2, . . . , 52) (step S155).

[0248] Here, the phase characteristic ∠H j,k The unwrap process for (k=1,2,...,52) is performed by subtracting the phase characteristic ∠H j,k ,∠H j,k+1 Regarding the phase difference |∠H j,k+1 -∠H j,k Each phase characteristic ∠H j,k This is a process of adding 2πn to (k=2, , 52). n is the phase difference |∠H j,k+1 -∠H j,k It is determined according to k so that | does not exceed π.

[0249] When k=1, the estimation processing unit 123 calculates the phase difference |∠H j,2 -∠H j,1 |∠H j,2 Add 2πn to

[0250] When k≧2, the estimation processing unit 123 calculates the phase difference |∠H j,k+1 -∠H j,k |∠H j,k+1 ,∠H j,k Add 2πn to both.

[0251] In other words, the unwrap process is performed by adjusting the phase characteristic ∠H between adjacent subcarriers. j,k ,∠H j,k+1 The phase difference between adjacent subcarriers is calculated by performing a process to prevent the phase difference between adjacent subcarriers from exceeding π. j,k+1 -∠H j,k The phase characteristic φ of the frequency response where | is less than or equal to π j,k This is the process of obtaining the

[0252] After step S155, the estimation processing unit 123 calculates the phase characteristic φ j,k (k=1,2,...,52) mean value m j (Average phase characteristic) is calculated by the following equation (step S156).

[0253]

number

[0254] Then, the estimation processing unit 123 calculates the starting sample number s j and the average phase characteristic m j is output (step S157).

[0255] Then, when it is determined in step S152 that the first sample number of the preamble has not been identified, or after step S157, the series of operations proceeds to step S16 in FIG.

[0256] In this way, the flowchart shown in FIG. 18 is executed in step S15 of FIG. 16 when the corresponding header data exists in the signal Sig_IQ, that is, when the radio frame has been successfully decoded.

[0257] FIG. 19 is a diagram for explaining the source estimation process in step S18 of FIG.

[0258] Referring to Figure 19, when it is determined in step S13 of Figure 16 that there is no header data corresponding to the detected signal, the estimation processing unit 123 performs an average phase characteristic extraction process on the signal detected in the signal detection process (step S181).

[0259] Then, the estimation processing unit 123 determines whether or not the first sample number of the preamble has been identified in the average phase characteristic extraction process (step S182).

[0260] In step S182, when it is determined that the first sample number of the preamble has been identified, the estimation processing unit 123 sets the start sample number obtained by performing the average phase characteristic extraction processing as s j1 The average phase characteristic is m j1 (step S183).

[0261] Then, the estimation processing unit 123 calculates the variable C u is initialized to an empty set, and the variable E u is initialized to an empty set (step S184).

[0262] Then, the estimation processing unit 123 sets z=1 (step S185). Here, z is an argument indicating each transmission source stored in the storage unit 124, and z=1, 2, . . . , Z. Z is the total number of transmission sources stored in the storage unit 124 when the flowchart shown in FIG. 19 is executed, and is an integer equal to or greater than 2. As will be described later in FIG. 21, the total number of transmission sources stored in the storage unit 124 may increase, and therefore Z is the total number of transmission sources stored in the storage unit 124 when the flowchart shown in FIG. 19 is executed.

[0263] After step S185, the estimation processing unit 123 z The number of data in the FIFO memory is n fifo It is determined whether the number is less than the number (step S186).

[0264] In step S186, the source u z The number of data in the FIFO memory is n fifo If it is determined that the number is less than z, the estimation processing unit 123 sets z=z+1 (step S187). Then, the series of operations proceeds to step S186. After that, in step S186, z The number of data in the FIFO memory is n fifo Steps S186 and S187 are repeatedly executed until it is determined that the number is not less than 100.

[0265] Then, in step S186, the source u z The number of data in the FIFO memory is n fifo If it is determined that the number is not less than 1, the estimation processing unit 123 z The data stored in the FIFO memory is used as input to execute the phase change rate estimation process, and the output is set as β1 (step S188).

[0266] Then, the estimation processing unit 123 estimates the source u z The starting sample number of the latest data (the data at the end of the FIFO) stored in the FIFO memory is set to s. j0 The average phase characteristic is m j0 Then, execute the following formula to find the error e u (u z ) is obtained (step S189). Here, the starting sample number s of the latest data is obtained. j0 and the average phase characteristic m j0 Using equation (4), the error e u (u z ) is obtained by starting sample number s j0 and the average phase characteristic m j0 is the start sample number s obtained in step S183 during the execution of the source estimation process.j1 and the average phase characteristic m j1 Therefore, the error e obtained using Eq. (4) u (u z ) is the starting sample number s j0 and the average phase characteristic m j0 and the starting sample number s j1 and the average phase characteristic m j1 This is because it is considered to be the most appropriate way to express the difference between

[0267]

number

[0268] Subsequently, the estimation processing unit 123 calculates the variable C u Sent to u z Add the variable E u Error e u (u z ) is added (step S190).

[0269] Then, the estimation processing unit 123 determines whether z=Z (step S191).

[0270] If it is determined in step S191 that z=Z is not true, the process proceeds to step S187, and after step S187, the process proceeds to step S186. Thereafter, steps S186, S188, S189, S190, S191, and S187 are repeatedly executed until it is determined in step S191 that z=Z is true.

[0271] Then, in step S191, when it is determined that z=Z, the estimation processing unit 123 calculates the error e u (u z ) is the smallest value of source u z is set to u^ (step S192). The notation u^ indicates that "^" is placed above u, as described in step S192 of FIG. 19. Also, in step S192, the error e u (u z) is the smallest value of source u z When there are multiple sources (=u^), any one of the sources has an error e u (u z ) is the smallest value of source u z It is obtained as (=u^).

[0272]

number

[0273] After step S192, the estimation processing unit 123 calculates the error e u (u ^ ) is the threshold e u thresh It is determined whether the threshold value e is equal to or less than the threshold value e (step S193). u thresh is, for example, 0.04.

[0274] In step S193, the error e u (u ^ ) is the threshold e u thresh If it is determined that the value is equal to or less than u, the estimation processing unit 123 estimates the source as u^ (step S194).

[0275] Then, in step S182, when it is determined that the first sample number of the preamble has not been identified, or in step S193, the error e u (u ^ ) is the threshold e u thresh If it is determined that the value is not equal to or less than the above, or after step S194, the source estimation process ends, and the series of operations proceeds to step S11 in FIG.

[0276] Also, in step S182, when it is determined that the first sample number of the preamble has not been identified, or in step S193, the error e u (u ^ ) is the threshold e u threshIf it is determined that the value is not equal to or less than the above, it is determined that the source cannot be estimated, and the series of operations proceeds to step S11 in FIG.

[0277] In the flowchart shown in FIG. 19, in step 193, the error e u (u^) is the threshold e u thresh If it is determined that the threshold value is less than or equal to the threshold value e u thresh The error e is less than or equal to u As a result, in the flowchart shown in FIG. 19, before obtaining the estimation result of the source in step S194, the error e u (u^) is the threshold e u thresh By determining whether it is equal to or less than the threshold value e u thresh is used as a kind of "final defense" and the error e u (u^) is the final protective barrier (= threshold e u thresh ), the estimation of the source is abandoned. u (u^) is the threshold e u thresh Determining whether or not the value is equal to or less than 1 has the technical significance of improving the reliability of the estimation result of the source.

[0278] In addition, when the flowchart shown in Figure 18 is executed in step S181 of Figure 19, the flowchart shown in Figure 18 is executed when it is determined in step S13 of Figure 16 that "there is no header data corresponding to the detected signal."

[0279] In this case, the flowchart shown in Fig. 18 is executed based on the signal Sig_IQ when the signal Sig_IQ does not contain corresponding header data. Then, when it is determined in step S152 of Fig. 18 that the first sample number of the preamble of the signal Sig_IQ when the signal Sig_IQ does not contain corresponding header data has not been identified, or after step S157, the series of operations proceeds to step S182 of Fig. 19.

[0280] The flowchart shown in Fig. 19 is executed when it is determined in step S13 of Fig. 16 that there is no header data corresponding to the detected signal Sig_IQ. Then, in step S181 of Fig. 19, the average phase characteristic extraction process is executed according to the flowchart of Fig. 18. In step S151 of the flowchart of Fig. 18, the estimation processing unit 123 specifies the first sample number of the preamble of the signal Sig_IQ when there is no header data corresponding to the signal Sig_IQ. When it is determined in step S152 of Fig. 18 that the first sample number of the preamble has been specified, steps S153 to S157 of Fig. 18 are executed sequentially based on the signal Sig_IQ when there is no header data corresponding to the signal Sig_IQ, and the starting sample number s j and the average phase characteristic m j As a result, in step S183 of FIG. 19, the start sample number s of the preamble of the signal Sig_IQ is obtained. j1 and the average phase characteristic m j1 is obtained.

[0281] In this way, when there is no corresponding header data in the signal Sig_IQ, the starting sample number s j and the average phase characteristic m j is obtained because the decoding of the radio frame failed and the header data was not obtained.

[0282] 19 is a flowchart for estimating the source of a wireless frame when decoding of the wireless frame fails. As a result, even when decoding of the wireless frame fails, the source of the wireless frame can be estimated.

[0283] In the flowchart shown in FIG. 19, in step S192, Z errors e u (u1)~e u (u Z ) with the error e u (u z ) is the smallest value of u z Since u^ is used, step S193 is not executed, and the source u obtained in step S192 is used. z (=u^) may be estimated as the source in step S194.

[0284] FIG. 20 is a flowchart for explaining the phase change rate estimation process in step S188 of FIG.

[0285] Referring to FIG. 20, in step S186 of FIG. 19, the source u z The number of data in the FIFO memory is n fifo If it is determined that the number is not less than 1, the estimation processing unit 123 z (s) in the FIFO memory j ,m j ) set, the subscripts are reassigned in the order of addition to the FIFO. Then, the subscript representing the order of addition to the FIFO is k (k=1,2,...,n fifo ) (step S1881).

[0286] Then, the estimation processing unit 123 calculates x k ,y k (k=1, 2, . . . , N) is calculated as follows (step S1882): fifo It is -1.

[0287]

number

[0288] Then, the estimation processing unit 123 calculates x k (k=1,2,...,N), the value of which is the threshold s thresh Let V be the set of indices of those that are: V={k|x k ≦s thresh Then, the estimation processing unit 123 calculates x k ,y k The set of those with an index that belongs to V, i.e., {x k |k∈V},{y k |k∈V}, and re-index x k’ (k'=1,2,···,M),y k’ Let (k'=1, 2, . . . , M) (step S1883).

[0289] where x k is a value that represents the interval between sample numbers, and if the value is large (i.e., the threshold s thresh (exceeds y) k Since the value of may exceed 2π, the x k ,y k Then, the threshold s thresh For example, s thresh = 10000. Therefore, in step S1883, the estimation processing unit 123 calculates x k ,y k to threshold s thresh x with a value of k’ ,y k’ Execute the process to extract.

[0290] After step S1883, the estimation processing unit 123 k’ For this, the value calculated by modulo 2π is changed to y k’ That is, the value of y k’ ←y k’ (mod 2π)(k′=1, 2, . . . , M) (step S1884).

[0291] Then, the estimation processing unit 123 calculates x k’ ,yk’ A regression line is fitted to (k'=1, 2, . . . , M) by the least squares method. That is, when the equation of the regression line is y=β0+β1x, β1 is calculated by the following equation (step S1885). Note that / x is the sum of x k’ is the average of y k’ Equation (7) is the average of x k’ and y k’ The sum of products for subcarrier k' is x k’ This indicates that β1 is calculated by dividing by the sum of squares for subcarrier k' of x and y. Note that the " / " in the notation / x and the " / " in the notation / y represent "-"s placed above x and y, respectively, as shown in step S1885 of FIG.

[0292]

number

[0293] β1 calculated by equation (7) constitutes the "phase change rate."

[0294] After step S1885, the estimation processing unit 123 outputs β1 (step S1886). After that, the series of operations proceeds to step S189 in FIG. 19. Then, in step S189 in FIG. 19, the estimation processing unit 123 calculates the error e u (u z ) is calculated.

[0295] FIG. 21 is a flowchart for explaining the detailed operation of step S17 in the flowchart shown in FIG.

[0296] 21, in step S16 of FIG. 16, when it is determined that the first sample number of the preamble has been identified for the detected signal Sig_IQ, the estimation processing unit 123 z (The source u acquired in step S14 of FIG. 16) z) is stored in the storage unit 124 (step S171).

[0297] In step S171, the source u z is determined to exist in the storage unit 124, the estimation processing unit 123 determines whether the source u is present among the Z sources stored in the storage unit 124. z Source u matches z0 (step S172).

[0298] Then, the estimation processing unit 123 estimates the source u z0 The starting sample number s is added to the end of the FIFO memory associated with j and the average phase characteristic m j (=Start sample number s acquired in the average phase characteristic extraction process described in step S15 of FIG. 16 (flowchart shown in FIG. 18) j and the average phase characteristic m j ) is saved (step S173).

[0299] On the other hand, in step S171, the source u z When it is determined that the source u does not exist in the storage unit 124, the estimation processing unit 123 z is stored in the storage unit 124 (step S174).

[0300] Then, the estimation processing unit 123 estimates the source u z A new FIFO memory is created in the storage unit 124 in association with the new FIFO memory (step S175).

[0301] Then, the estimation processing unit 123 stores the start sample number s in the new FIFO memory. j and the average phase characteristic m j (=Start sample number s acquired in the average phase characteristic extraction process described in step S15 of FIG. 16 (flowchart shown in FIG. 18) j and the average phase characteristic m j ) is saved (step S176).

[0302] After step S173 or step S176, the series of operations proceeds to step S11 in FIG.

[0303] In the flowchart shown in FIG. 21, "YES" in step S171 → step S172 → step S173 is to store the start sample number s in the FIFO memory associated with the transmission source already stored in the storage unit 124. j and the average phase characteristic m j This is the step to save the data.

[0304] That is, in the process of "YES" in step S171, step S172, and step S173, the source u z (The source u obtained in step S14 of FIG. 16) z ) is determined to exist in the storage unit 124 (see "YES" in step S171), the "start sample number and average phase characteristic" is added to the "start sample number and average phase characteristic" stored in the FIFO memory associated with the transmission source already stored in the storage unit 124, and the start sample number s j and the average phase characteristic m j (=Start sample number s acquired in the average phase characteristic extraction process described in step S15 of FIG. 16 (flowchart shown in FIG. 18) j and the average phase characteristic m j ) is saved.

[0305] Therefore, each time the estimation processing unit 123 executes "YES" in step S171, step S172, and step S173, the source u z Source u matches z0 The FIFO memory associated with the starting sample number s j and the average phase characteristic m j The characteristic value C consists of j can be accumulated.

[0306] As a result, it is possible to increase the characteristic values (start sample number and average phase characteristic) when the wireless frame can be decoded, and the estimation processing unit 123 can estimate the source u acquired from the header data when the wireless frame can be decoded. z The characteristic value C stored in the FIFO memory associated with j (i.e., the correct characteristic value C j 19), if the wireless frame cannot be decoded, in step S18 (the flowchart shown in FIG. 19), the source u of the wireless frame can be more accurately estimated based on the signal Sig_IQ when the corresponding header data is not present in the signal Sig_IQ.

[0307] On the other hand, in the flowchart shown in FIG. 21, "NO" in step S171 → step S174 → step S175 → step S176 is z does not exist in the storage unit 124, the source u obtained from the header data z and source u z and a "new FIFO memory" associated with the starting sample number s is added to the storage unit 124, and the starting sample number s is added to the new FIFO memory. j and the average phase characteristic m j (=Start sample number s acquired in the average phase characteristic extraction process described in step S15 of FIG. 16 (flowchart shown in FIG. 18) j and the average phase characteristic m j ) is saved.

[0308] That is, in the process of "NO" in step S171, step S174, step S175, and step S176, the source u z (The source u acquired in step S14 of FIG. 16 z ) does not exist in the storage unit 124 (see "NO" in step S171), the source u obtained from the header data z and source u z and a "new FIFO memory" associated with the starting sample number s is added to the storage unit 124, and the starting sample number s is added to the new FIFO memory.j and the average phase characteristic m j (=Start sample number s acquired in the average phase characteristic extraction process described in step S15 of FIG. 16 (flowchart shown in FIG. 18) j and the average phase characteristic m j ) is saved.

[0309] This allows the "new source u" obtained from the header data to be decoded when the wireless frame is successfully decoded. z " can be stored in the storage unit 124, and the "new source u z The characteristic value C when a wireless frame is transmitted from j (Start sample number s j and the average phase characteristic m j ) can be stored in FIFO memory.

[0310] As a result, if the wireless frame can be decoded, the estimation processing unit 123 estimates the source u z The characteristic value C stored in the FIFO memory associated with j ("New source u z " and the characteristic value C j ), if the wireless frame cannot be decoded, in step S18 (the flowchart shown in FIG. 19), the number Z of the increased source u in the storage unit 124 is calculated based on the signal Sig_IQ when the corresponding header data does not exist in the signal Sig_IQ. z0 The "source of the wireless frame" can be accurately estimated by referring to the

[0311] The execution of step S171 "YES" → step S172 → step S173 by the estimation processing unit 123 means that "every time the detection processing unit 122 detects the signal Sig_IQ, the estimation processing unit 123 detects the source u z (The source u obtained in step S14 of FIG. 16) z) is determined to exist in the storage unit 124 (see "YES" in step S171), the "start sample number and average phase characteristic" is added to the "start sample number and average phase characteristic" stored in the FIFO memory associated with the transmission source already stored in the storage unit 124, and the start sample number s j and the average phase characteristic m j (=Start sample number s acquired in the average phase characteristic extraction process described in step S15 of FIG. 16 (flowchart shown in FIG. 18) j and the average phase characteristic m j This is equivalent to executing a "save process" to save the

[0312] Furthermore, the execution of "YES" in step S171, step S172, and step S173 by the estimation processing unit 123 means that "every time the detection processing unit 122 detects the signal Sig_IQ, the estimation processing unit 123 detects the source u z (The source u obtained in step S14 of FIG. 16) z ) is determined to exist in the storage unit 124 (see "YES" in step S171), the "start sample number and average phase characteristic" is added to the "start sample number and average phase characteristic" stored in the FIFO memory associated with the transmission source already stored in the storage unit 124, and the start sample number s j and the average phase characteristic m j (=Start sample number s acquired in the average phase characteristic extraction process described in step S15 of FIG. 16 (flowchart shown in FIG. 18) j and the average phase characteristic m j This corresponds to executing the "Save the file" step.

[0313] Furthermore, the execution of step S171 "NO" → step S174 → step S175 → step S176 by the estimation processing unit 123 means that "every time the detection processing unit 122 detects the signal Sig_IQ, the estimation processing unit 123 detects the source u z (The source u obtained in step S14 of FIG. 16) z ) does not exist in the storage unit 124 (see "NO" in step S171), the source u obtained from the header data z and source uz and a "new FIFO memory" associated with the starting sample number s is added to the storage unit 124, and the starting sample number s is added to the new FIFO memory. j and the average phase characteristic m j (=Start sample number s acquired in the average phase characteristic extraction process described in step S15 of FIG. 16 (flowchart shown in FIG. 18) j and the average phase characteristic m j This is equivalent to executing a "save process" to save the

[0314] Furthermore, the execution of step S171 "NO" → step S174 → step S175 → step S176 by the estimation processing unit 123 means that "every time the detection processing unit 122 detects the signal Sig_IQ, the estimation processing unit 123 detects the source u z (The source u obtained in step S14 of FIG. 16) z ) does not exist in the storage unit 124 (see "NO" in step S171), the source u obtained from the header data z and source u z and a "new FIFO memory" associated with the starting sample number s is added to the storage unit 124, and the starting sample number s is added to the new FIFO memory. j and the average phase characteristic m j (=Start sample number s acquired in the average phase characteristic extraction process described in step S15 of FIG. 16 (flowchart shown in FIG. 18) j and the average phase characteristic m j This corresponds to executing the "Save the file" step.

[0315] The reason for terminating the average phase characteristic extraction process when it is determined in step S152 of the flowchart shown in Figure 18 that the first sample number of the preamble has not been identified for the detected signal (= signal Sig_IQ detected by the detection processing unit 122) will be explained.

[0316] FIG. 22 is a diagram for explaining the reason why the average phase characteristic extraction process is terminated when it is determined in step S152 of FIG. 18 that the first sample number of the preamble has not been identified.

[0317] Referring to FIG. 22, the preamble PreAMB_IQ is a preamble of the IQ data signal Sig_IQ, and the preamble PreAMB_u z is the source u acquired in step S14 of FIG. z The IQ data signal Sig_IQ does not have any header data (see the header data surrounded by the dotted line).

[0318] In step S152 of Fig. 18, it is determined whether the first sample number of the preamble PreAMB_IQ has been identified. If it is determined in step S152 that the first sample number of the preamble PreAMB_IQ has not been identified, the source u that is synchronized with the preamble PreAMB_IQ is z Preamble PreAMB_u in the data z Since the start sample number of the preamble PreAMB_u cannot be identified, steps S153 to S156 in FIG. z Based on the average phase characteristic m j Therefore, when it is determined in step S152 that the leading sample number of the preamble has not been identified for the detected signal (=signal Sig_IQ detected by the detection processing unit 122), the average phase characteristic extraction process is terminated.

[0319] According to the flowchart shown in FIG. 16 (including the flowcharts shown in FIGS. 17 to 20), when it is determined that header data corresponding to the signal Sig_IQ detected by the detection processing unit 122 exists (see "YES" in step S13 of FIG. 16), the estimation processing unit 123 derives the source u of the wireless frame (=wireless frame including the signal Sig_IQ) from the header data corresponding to the signal Sig_IQ. z (see step S14 in FIG. 16), and obtains the starting sample number s based on the preamble of the signal Sig_IQ when the corresponding header data exists in the signal Sig_IQ. jand the average phase characteristic m j (see step S15 in FIG. 16 (the flowchart shown in FIG. 18)). Then, the estimation processing unit 123 obtains the source u z When the source u obtained in step S14 is z The starting sample number s is stored in the FIFO. j and the average phase characteristic m j A saving process is executed to save the data (see step S17 in FIG. 16).

[0320] On the other hand, when the estimation processing unit 123 determines that there is no header data corresponding to the signal Sig_IQ detected by the detection processing unit 122 (see "NO" in step S13 of Figure 16), it executes a source estimation process (see step S18 of Figure 16) to calculate a characteristic value specific to the transmission path between the transmitter and receiver of the wireless frame based on the signal Sig_IQ when there is no header data corresponding to the signal Sig_IQ detected by the output processing unit 122, detects a source having a characteristic value closest to the calculated characteristic value from the memory unit 124, and executes an estimation process to estimate the detected source as the source of the wireless frame (see step S18 of Figure 16 and the flowcharts shown in Figures 18 to 20).

[0321] Thus, according to the flowchart shown in Figure 16 (including the flowcharts shown in Figures 17 to 20), the estimation processing unit 123 acquires the source both when header data corresponding to the signal Sig_IQ detected by the detection processing unit 122 is present and when header data corresponding to the signal Sig_IQ detected by the detection processing unit 122 is not present.

[0322] When the signal Sig_IQ does not contain the corresponding header data, the signal Sig_IQ is a signal detected from the IQ data when the decoding of the wireless frame fails, and the header data is data obtained when the decoding of the wireless frame is successful.

[0323] As a result, the estimation processing unit 123 acquires the source both when the wireless frame is successfully decoded and when the wireless frame is unsuccessfully decoded. Therefore, even if the wireless frame is unsuccessfully decoded, the source u z can be estimated.

[0324] Furthermore, when the signal Sig_IQ detected by the detection processing unit 122 contains the corresponding header data, the estimation processing unit 123 determines whether the source u z When the source u obtained in step S14 of FIG. z The starting sample number s is stored in the FIFO. j and the average phase characteristic m j Therefore, every time it is determined that the header data corresponding to the signal Sig_IQ detected by the detection processing unit 122 exists, the source u z "Start sample number s" j and the average phase characteristic m j The set of "start sample number s" stored in the FIFO memory can be stored in the FIFO memory. j and the average phase characteristic m j The set of "start sample number s" is used to estimate the transmission source in the transmission source estimation process (flowchart shown in FIG. 19) when there is no header data corresponding to the signal Sig_IQ detected by the detection processing unit 122 (see steps S185 to S194 in FIG. 19). As a result, when there is no header data corresponding to the signal Sig_IQ detected by the detection processing unit 122, the "start sample number s" stored in the FIFO memory is used to estimate the transmission source each time it is determined that there is header data corresponding to the signal Sig_IQ detected by the detection processing unit 122. j and the average phase characteristic m j By referring to the "pair of messages", the sender can be estimated more accurately.

[0325] Furthermore, according to the flowchart of FIG. 17 showing the signal detection process described in step S11 of FIG. 16, the detection processing unit 122 detects the sample d of the IQ data. i (i indicates the order of sample acquisition, i = 0, 1, 2,...)i .rss first reaches the threshold r thresh The timestamp t when start to signal strength d i .rss first reaches the threshold r thresh After the signal strength reaches d i .rss first reaches the threshold r thresh The timestamp when it becomes less than d i Time until .ts d i .ts-t start is calculated as the duration of the signal Sig_IQ, and the duration d i .ts-t start to the estimation processing unit 123. Then, the estimation processing unit 123 outputs the duration d i .ts-t start from the detection processing unit 122, the duration d of the signal Sig_IQ i .ts-t start and the duration of the header data and the duration of the signal Sig_IQ d i .ts-t start and the duration of the header data, and executes a determination process based on the determined non-overlapping time to determine whether or not there is header data corresponding to the signal Sig_IQ detected by the detection processing unit 122.

[0326] In this case, the estimation processing unit 123 determines whether the non-overlapping time is equal to or smaller than the threshold w thresh If the non-overlapping time is less than or equal to the threshold w thresh If the signal Sig_IQ is longer than 1, it is determined that the corresponding header data does not exist in the signal Sig_IQ.

[0327] Furthermore, according to the average phase characteristic extraction process shown in step S181 of FIG. 19 (the flowchart of FIG. 18), the estimation processing unit 123 extracts the frequency response H j,k (see step S154 in FIG. 18), and the obtained frequency response H j,k The phase characteristics of the subcarriers are averaged to obtain the average phase characteristic m j(see step S156 in FIG. 18), and the calculated average phase characteristic m j and the starting sample number s of the signal Sig_IQ j and the set (starting sample number s j , average phase characteristic m j ) as a characteristic value (the average phase characteristic extraction process executed by the flowchart of FIG. 18, which executes the average phase characteristic extraction process described in step S181 of FIG. 19). j , average phase characteristic m j ) constitutes the "first characteristic value", and the average phase characteristic extraction process described in step S181 of FIG. 19 constitutes the "second average phase characteristic extraction process".

[0328] In the flowchart of FIG. 18, the estimation processing unit 123 divides the calculation result obtained by performing a fast Fourier transform (FFT) on the long training field (LTF) part of the preamble of frame j by the calculation result obtained by performing a fast Fourier transform (FFT) on the long training field (LTF) part of the preamble of a frame consisting of a known signal in step S154 of FIG. 18 to obtain the frequency response H j,k (k=1,2,···,52).

[0329] For example, in IEEE802.11a, the preamble of a wireless frame is composed of L-STF / L-LTF / L-SIG. Therefore, in the average phase characteristic extraction process, the estimation processing unit 123 divides the calculation result obtained by fast Fourier transforming "L-LTF" of the preamble of frame j (composed of the signal Sig_IQ detected by the detection processing unit 122) by the calculation result obtained by fast Fourier transforming "L-LTF" of the preamble of a frame composed of a known signal, to obtain the frequency response H j,k (k=1, 2, . . . , 52) can be obtained. Even when the wireless standard is other than IEEE802.11a, such as IEEE802.11g, the LTF is included in the frame preamble. Therefore, the estimation processing unit 123 can obtain the frequency response Hj,k (k=1,2,···,52) can be obtained.

[0330] Furthermore, according to the phase change rate estimation process shown in step S188 of FIG. 19 (the phase change rate estimation process executed according to the flowchart shown in FIG. 20), the estimation processing unit 123 z In the estimation process (flowchart shown in FIG. 19), the start sample number and the average phase characteristic obtained in the average phase characteristic extraction process (second average phase characteristic extraction process) are respectively set as s j1 ,m j1 19 (see step S183 in FIG. 19), and a set of characteristic values (s j ,m j ) is processed to change the order of addition to the storage unit 124 to obtain the set of characteristic values (s j ,m j ) as a set of characteristic values (s k ,m k )(k=1,2,...,n fifo ) (see step S1881 in Figure 20), and k (=s k+1 -s k )(k=1,2,···,N(=n fifo -1)) is the explanatory variable, and y k (=m k+1 -m k ) is used as an objective function (see steps S1882 to S1885 in FIG. 20), and a set of characteristic values (s j ,m j ) the most recent characteristic value (starting sample number s j0 and the average phase characteristic m j0 ) and the characteristic values of frame j (starting sample number s j1 and the average phase characteristic m j1 The error e u The calculation of Z errors e u(see steps S185 to S191 in FIG. 19), and u The smallest error e u_min is obtained is estimated to be the source of the wireless frame (= the wireless frame including the signal Sig_IQ detected by the detection processing unit 122) (see steps S192 and S194 in FIG. 19). In this case, step S193 in FIG. 19 does not need to be executed for the reasons described above.

[0331] Then, the estimation processing unit 123 executes step S193 in FIG. 19 in the estimation process to obtain the minimum error e u_min is the threshold e u thresh When the threshold e u thresh The minimum error e is less than or equal to u_min is obtained is estimated as the source of the wireless frame (=wireless frame including the signal Sig_IQ detected by the detection processing unit 122).

[0332] Furthermore, in the storage process, the estimation processing unit calculates the frequency response H j,k (k=1, 2, . . . , 52) is calculated (see step S154 in the flowchart of FIG. 18, which executes the average phase characteristic extraction process in step S15 of FIG. 16), and the calculated frequency response H j,k The phase characteristics of (k=1,2,...,52) are averaged for the subcarriers to obtain the average phase characteristic m j Calculate the average phase characteristic m j and the starting sample number s of the preamble of frame j j and the set (starting sample number s j , average phase characteristic m j ) as a characteristic value (see steps S153 to S156 in the flowchart of FIG. 18, which executes the average phase characteristic extraction process described in step S15 of FIG. 16). j , average phase characteristic m j) constitutes the "second characteristic value", and the "average phase characteristic extraction process described in step S15 of FIG. 16" constitutes the "first average phase characteristic extraction process".

[0333] In the flowchart shown in FIG. 16, after step S18 is executed, the start sample number s obtained by executing the source estimation process in step S18 is used. j and the average phase characteristic m j The reason why the process proceeds to step S11 without storing the message in association with the sender in the storage unit 124 is as follows.

[0334] Step S18 is executed when the decoding of the wireless frame fails. When the decoding of the wireless frame fails, the start sample number s obtained by executing the source estimation process of step S18 is used. j1 and the average phase characteristic m j1 (See step S183 in FIG. 19) is the characteristic value C stored in FIFO1, FIFO2, . . . associated with the transmission sources u1, u2, . . . of the storage unit 124 in step S17 in FIG. 16. 1_1 ,C 2_1 ,···,C N_1 ;C 1_2 ,C 2_2 ,···,C N_2 The starting sample number s that constitutes each of j0 and the average phase characteristic m j0 Since there is an error, the starting sample number s j1 and the average phase characteristic m j1 , . . . of the storage unit 124, is stored in association with the transmission source u^ estimated in step S194 of FIG. 19, the characteristic value C stored in FIFO1, FIFO2, . . . 1_1 ,C 2_1 ,···,C N_1 ;C 1_2 ,C 2_2 ,···,C N_2 , . . . deteriorates, making it difficult to accurately estimate the source of the signal Sig_IQ in the source estimation process of step S18.

[0335] In an embodiment of the present invention, the operation of analysis device 10 may be realized by software. In this case, analysis device 10 includes storage unit 124 and a computer. The computer includes a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory). The ROM stores a program Prog_A consisting of the steps of the flowchart shown in FIG. 16 (including the flowcharts shown in FIGS. 17 to 21).

[0336] The computer (CPU) reads the program Prog_A from the ROM, executes the read program Prog_A, estimates the source of the wireless frame based on the IQ data, and acquires the source of the wireless frame based on the header data. The RAM stores the start sample number s j and the average phase characteristic m j etc. are temporarily stored.

[0337] Furthermore, the program Prog_A may be distributed by being recorded on a recording medium such as a CD or a DVD. When the recording medium on which the program Prog_A is recorded is attached to a computer, the computer (CPU) reads and executes the program Prog_A from the recording medium, estimates the source of the wireless frame based on the IQ data, and acquires the source of the wireless frame based on the header data.

[0338] Therefore, the recording medium on which the program Prog_A is recorded is a computer-readable recording medium.

[0339] In the embodiment of the present invention, if the volume of IQ data is so large that it is difficult for the analysis device 10 to estimate the source, the sensor devices 20, 30, and 40 may have the analysis device 10 built in.

[0340] As described above, every time the analysis device 10 receives the IQ data (D1_env), it sequentially executes step S11 → "YES" in step S12 → "YES" in step S13 → step S14 → step S15 → "YES" in step S16 → step S17 in the flowchart shown in FIG. 16 to obtain the IQ data of the sender u z The characteristic value (starting sample number s j , average phase characteristic m j ) to accumulate.

[0341] This process is performed by extracting the source u from the header data corresponding to the signal Sig_IQ. z When the signal Sig_IQ contains the corresponding header data, the sender of the signal Sig_IQ is the sender u z Then, the source u obtained from the header data is estimated. z is a valid source, so the source of the signal Sig_IQ is the source u z Therefore, estimating that

[0342] Therefore, each time the analysis device 10 receives the IQ data (D1_env), it sequentially executes step S11 → "YES" in step S12 → "YES" in step S13 → step S14 → step S15 → "YES" in step S16 → step S17. z You will learn:

[0343] On the other hand, if there is no corresponding header data in the signal Sig_IQ, the analysis device 10 performs step S18 in FIG. 16 to determine whether the “transmission source u z and characteristic value C j (i.e., by referring to the correct answer), the sender of the signal Sig_IQ is estimated when the signal Sig_IQ does not contain the corresponding header data.

[0344] In this case, it is possible to realize the functions of the analysis device 10 using artificial intelligence (AI).

[0345] In this case, the artificial intelligence includes a learning model and a storage unit 124. The learning model causes a computer to execute each step of the above-described program Prog_A, and obtains the source u of the signal Sig_IQ when the corresponding header data exists in the signal Sig_IQ. z The correct answer is learned, and the learned correct answer is stored in the memory unit 124. At the same time, the correct answer after learning stored in the memory unit 124 is referenced to estimate the source u^ of the signal Sig_IQ when the header data corresponding to the signal Sig_IQ does not exist.

[0346] According to the above-described embodiment, the analysis device according to the embodiment of the present invention comprises: a reception processing unit that receives IQ data, which is data obtained by down-converting the frequency of a received signal when a wireless frame is received, from a sensor device, and receives header data of the wireless frame from a header data detection device; a synchronization processing unit that synchronizes the IQ data and header data received by the reception processing unit; a detection processing unit that detects a signal Sig_IQ based on the IQ data synchronized by the synchronization processing unit and the IQ data of the header data; a storage unit that stores Z (Z is an integer equal to or greater than 1) transmission sources, each of which is a transmission source of a wireless frame, Z pieces of transmission source identification information associated with the Z transmission sources, and Z characteristic values associated with the Z transmission source identification information, each of which is a characteristic value specific to a transmission path between a transmitter and a receiver of the wireless frame; When it is determined that header data corresponding to the signal Sig_IQ detected by the detection processing unit is not present, an estimation processing unit is provided which calculates a first characteristic value, which is a characteristic value specific to the transmission path between the transmitter and receiver of the wireless frame, based on the signal Sig_IQ when the header data is not present, detects a sender having a characteristic value closest to the calculated first characteristic value from Z senders stored in a memory unit, and estimates the detected sender as the sender of the wireless frame, and when it is determined that header data corresponding to the signal Sig_IQ detected by the detection processing unit is present, obtains the sender of the wireless frame from the header data corresponding to the signal Sig_IQ.

[0347] If the analysis device includes a reception processing unit, a synchronization processing unit, a detection processing unit, a storage unit, and an estimation processing unit, when the header data corresponding to the signal Sig_IQ is not present, the sender of the wireless frame is estimated, and when the header data corresponding to the signal Sig_IQ is present, the sender of the wireless frame is acquired. When decoding of the wireless frame fails, the header data corresponding to the signal Sig_IQ is not present, and when decoding of the wireless frame is successful, the header data corresponding to the signal Sig_IQ is present. Therefore, even if decoding of the wireless frame fails, the sender of the wireless frame can be estimated.

[0348] Furthermore, the program according to the embodiment of the present invention is A program executed in the above-described "analysis device according to an embodiment of the present invention," The analysis device is a storage unit that stores Z (Z is an integer equal to or greater than 1) transmission sources, each of which is a transmission source of a wireless frame, Z pieces of transmission source identification information associated with the Z transmission sources, and Z characteristic values associated with the Z transmission source identification information, each of which is a characteristic value specific to a transmission path between a transmitter and a receiver of the wireless frame; The program is a first step in which a reception processing unit receives, from a sensor device, IQ data, which is data obtained by down-converting the frequency of a received signal when a wireless frame is received, and receives, from a header data detection device, header data of the wireless frame; a second step in which a synchronization processor synchronizes the IQ data and header data received in the first step; a third step in which the detection processing unit detects the signal Sig_IQ based on the IQ data of the IQ data and the header data synchronized in the second step; When the estimation processing unit determines that no header data corresponding to the signal Sig_IQ detected in the third step exists, it calculates a first characteristic value, which is a characteristic value specific to the transmission path between the transmitter and receiver of the wireless frame, based on the signal Sig_IQ when no header data exists, detects a sender having a characteristic value closest to the calculated first characteristic value from Z senders stored in the memory unit, and estimates the detected sender as the sender of the wireless frame; and when it determines that header data corresponding to the signal Sig_IQ detected by the detection processing unit exists, it is a program that causes a computer to execute a fourth step of acquiring the sender of the wireless frame from the header data corresponding to the signal Sig_IQ.

[0349] When the program according to the embodiment of the present invention causes a computer to execute steps 1 to 4, if the signal Sig_IQ does not contain corresponding header data, the source of the wireless frame is estimated, and if the signal Sig_IQ contains corresponding header data, the source of the wireless frame is acquired. If decoding of the wireless frame fails, the signal Sig_IQ contains no corresponding header data, and if decoding of the wireless frame is successful, the signal Sig_IQ contains corresponding header data. Therefore, even if decoding of the wireless frame fails, the source of the wireless frame can be estimated.

[0350] In this embodiment of the present invention, the starting sample number s j and the average phase characteristic mj constitutes the "characteristic value" and is the starting sample number s obtained by the average phase characteristic extraction process (flowchart of FIG. 18) described in step S181 of FIG. 19. j and the average phase characteristic m j constitutes the "first characteristic value" and is the starting sample number s obtained by the average phase characteristic extraction process (flowchart in FIG. 18) described in step S15 in FIG. 16. j and the average phase characteristic m j constitutes a "second characteristic value."

[0351] In addition, in the embodiment of the present invention, the threshold value w thresh constitutes the "first threshold" and the threshold r thresh constitutes the "second threshold" and the threshold e u thresh constitutes the "third threshold."

[0352] Furthermore, in this embodiment of the present invention, the third communication interface 11 constitutes a "reception processing unit."

[0353] Furthermore, in the embodiment of the present invention, each of MAC1, MAC2, ... shown in Figure 3 constitutes "identification information of a sender", and MAC1, MAC2, ... constitute "identification information of Z senders".

[0354] Furthermore, in the embodiment of the present invention, the "C" shown in FIG. 1_1 ,C 2_1 ,···,C N_1 ";"C 1_2 ,C 2_2 ,···,C N_2 ";... constitutes "Z characteristic values".

[0355] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims. [Industrial Applicability]

[0356] The present invention is applicable to an analysis device, a program to be executed by a computer, and a computer-readable recording medium on which the program is recorded. [Explanation of symbols]

[0357] 10 analysis device, 11 third communication interface, 12 source estimation unit, 20, 30, 40 sensor device, 21, 51 antenna, 22, 52 RF processing unit, 23 synchronization time management unit, 24 IQ data acquisition unit, 25 envelope data acquisition unit, 26 early detection data generation unit, 27 first communication interface, 50 personal computer (PC), 53 BB processing unit, 54 header acquisition processing unit, 55 second communication interface, 60, 70, 80 communication equipment, 100 wireless communication system, 121 synchronization processing unit, 122 detection processing unit, 123 estimation processing unit, 124 memory unit, 1211 first FIFO, 1212 second FIFO, 1213 offset acquisition processing unit, 1214 offset value holding unit, 1215 correction header data acquisition unit.

Claims

1. a reception processing unit that receives IQ data from a sensor device, the IQ data being data obtained by down-converting the frequency of a received signal when a wireless frame is received, and receives header data of the wireless frame from a header data detection device; a synchronization processing unit that synchronizes the IQ data and header data received by the reception processing unit; a detection processing unit that detects a signal Sig_IQ based on the IQ data of the header data and the IQ data synchronized by the synchronization processing unit; a storage unit that stores Z (Z is an integer equal to or greater than 2) transmission sources, each of which is a transmission source of the wireless frame, Z pieces of transmission source identification information associated with the Z transmission sources, and Z characteristic values associated with the Z transmission source identification information, each of which is a characteristic value specific to a transmission path between a transmitter and a receiver of the wireless frame; an analysis device comprising: an estimation processing unit that, when it is determined that header data corresponding to the signal Sig_IQ detected by the detection processing unit is not present, calculates a first characteristic value that is a characteristic value specific to the transmission path between the transmitter and receiver of the wireless frame based on the signal Sig_IQ when the header data is not present, detects a sender having a characteristic value closest to the calculated first characteristic value from the Z senders stored in the memory unit, and estimates the detected sender as the sender of the wireless frame; and, when it is determined that header data corresponding to the signal Sig_IQ detected by the detection processing unit is present, acquires the sender of the wireless frame from the header data corresponding to the signal Sig_IQ.

2. 2. The analysis device of claim 1, wherein when the estimation processing unit determines that header data corresponding to the signal Sig_IQ detected by the detection processing unit is present, the estimation processing unit acquires the source of the wireless frame, and then further calculates a second characteristic value for the acquired source of the wireless frame based on the signal Sig_IQ when the header data is present, which is a characteristic value specific to the transmission path between the transmitter and receiver of the wireless frame, and performs a storage process to store the second characteristic value in association with a source among the Z sources stored in the memory unit that matches the source of the wireless frame acquired from the header data.

3. 3. The analysis device of claim 2, wherein the estimation processing unit, in the storage process, performs a first average phase characteristic extraction process in which a frequency response in a transmission path between a transmitter and a receiver of the wireless frame is calculated based on the signal Sig_IQ when the header data is present, the phase characteristics of the calculated frequency response are averaged for subcarriers to calculate an average phase characteristic, and the combination of the calculated average phase characteristic and the start sample number of the preamble of the signal Sig_IQ (start sample number, average phase characteristic) is calculated as the second characteristic value.

4. The analysis device described in any one of claims 1 to 3, wherein the estimation processing unit performs a determination process in which, when the non-overlapping time between the duration of the signal Sig_IQ and the duration of the header data in the IQ data and header data synchronized by the synchronization processing unit is less than or equal to a first threshold, it determines that header data corresponding to the signal Sig_IQ detected by the detection processing unit is present, and when the non-overlapping time is longer than the first threshold, it determines that header data corresponding to the signal Sig_IQ detected by the detection processing unit is not present.

5. The detection processing unit detects the sample d of the signal Sig_IQ. ｉ (i indicates the order of sample acquisition, i = 0, 1, 2, ...) ｉ The timestamp t when the RSS first becomes equal to or greater than the second threshold. ｓｔａｒｔ from the signal strength d ｉ The signal strength d after the rss first becomes equal to or greater than the second threshold ｉ . The timestamp d when the rss first falls below the second threshold ｉ Time d until ts ｉ .ts-t ｓｔａｒｔ as the duration of the signal Sig_IQ, and output the duration of the signal Sig_IQ thus obtained to the estimation processing unit; 5. The analysis device according to claim 4, wherein when the estimation processing unit receives the duration of the signal Sig_IQ from the detection processing unit, the estimation processing unit calculates the non-overlapping time based on the duration of the signal Sig_IQ and the duration of the header data, and performs the determination processing based on the calculated non-overlapping time.

6. 6. The analysis device according to claim 1, wherein the estimation processing unit, in the estimation process, calculates a frequency response in a transmission path between a transmitter and a receiver of the radio frame based on a preamble of the signal Sig_IQ when the header data is not present, performs processing to prevent a phase difference between adjacent subcarriers from exceeding π with respect to the phase characteristic of the calculated frequency response, thereby acquiring a phase characteristic of the frequency response in which the phase difference between the adjacent subcarriers is π or less, averages the phase characteristics of the acquired frequency response for subcarriers to calculate an average phase characteristic, and executes a second average phase characteristic extraction process to obtain, as the first characteristic value, a pair of the calculated average phase characteristic and a start sample number of the preamble (start sample number, average phase characteristic).

7. 7. The analysis device according to claim 6, wherein the estimation processing unit, in the second average phase characteristic extraction process, obtains the frequency response by dividing a calculation result obtained by fast Fourier transforming a Long Training Field portion of a preamble of frame j consisting of the signal Sig_IQ detected by the detection processing unit by a calculation result obtained by fast Fourier transforming a Long Training Field portion of a preamble of a frame consisting of a known signal.

8. 8. The analysis device according to claim 6, wherein the estimation processing unit further determines whether the first sample number of a preamble has been identified for the signal Sig_IQ detected by the detection processing unit in the second average phase characteristic extraction processing, and when it determines that the first sample number has been identified, obtains the set (start sample number, average phase characteristic) as the first characteristic value.

9. The analysis device according to claim 8 , wherein the estimation processing unit further terminates the estimation process when it determines that the first sample number has not been identified in the second average phase characteristic extraction process.

10. The first characteristic value is a starting sample number s of a frame j of the signal Sig_IQ detected by the detection processing unit. ｊ１ and the average phase characteristic m ｊ１ It consists of In the estimation process, the estimation processing unit calculates the starting sample number and the average phase characteristic obtained in the second average phase characteristic extraction process as s ｊ１ , m ｊ１ and a set of characteristic values (s ｊ , m ｊ ) is processed to change the order of addition to the storage unit to the set of characteristic values (s ｊ , m ｊ ) as a set of characteristic values (s ｋ , m ｋ )(k=1,2,...,n ｆｉｆｏ (n ｆｉｆｏ is the maximum number of characteristic values that can be stored in association with one source. ｋ =s ｋ＋１ -s ｋ (k=1,2,...,N(=n ｆｉｆｏ -1)) is an explanatory variable, and y ｋ = m ｋ＋１ -m ｋ (k=1,2,...,N(=n ｆｉｆｏ The phase change rate β is the slope of the regression function with the objective function １ and performing a phase change rate estimation process to obtain the phase change rate β １ The most recent characteristic value (s ｊ０ , m ｊ０ ) and the characteristic value (s ｊ１ , m ｊ１ ) and the error e ｕ for all Z transmission sources stored in the storage unit to obtain Z errors, and estimates the transmission source that obtains the smallest error among the obtained Z errors as the transmission source of the wireless frame.

11. The analysis device according to claim 10, wherein the estimation processing unit further estimates, in the estimation process, when the minimum error is equal to or less than a third threshold, the source when the minimum error equal to or less than the third threshold is obtained as the source of the wireless frame.

12. A program executed in the analysis device according to any one of claims 1 to 11, The analysis device a storage unit that stores Z (Z is an integer equal to or greater than 2) transmission sources, each of which is a transmission source of a wireless frame, Z pieces of transmission source identification information associated with the Z transmission sources, and Z characteristic values associated with the Z transmission source identification information, each of which is a characteristic value specific to a transmission path between a transmitter and a receiver of the wireless frame; The program a first step in which a reception processing unit receives, from a sensor device, IQ data, which is data obtained by down-converting the frequency of a received signal when the wireless frame is received, and receives, from a header data detection device, header data of the wireless frame; a second step in which a synchronization processing unit synchronizes the IQ data and header data received in the first step; a third step in which a detection processing unit detects a signal Sig_IQ based on the IQ data of the IQ data and header data synchronized in the second step; a fourth step of executing an estimation process in which, when the estimation processing unit determines that no header data corresponding to the signal Sig_IQ detected in the third step is present, the estimation processing unit calculates a first characteristic value, which is a characteristic value specific to the transmission path between the transmitter and receiver of the wireless frame, based on the signal Sig_IQ when the header data is not present, detects a sender having a characteristic value closest to the calculated first characteristic value from the Z senders stored in the memory unit, and estimates the detected sender as the sender of the wireless frame; and, when the estimation processing unit determines that header data corresponding to the signal Sig_IQ detected by the detection processing unit is present, acquires the sender of the wireless frame from the header data corresponding to the signal Sig_IQ.

13. 13. The program for causing a computer to execute the program described in claim 12, wherein, when the estimation processing unit determines in the fourth step that header data corresponding to the signal Sig_IQ detected in the third step is present, it acquires the source of the wireless frame, and then further performs a storage process to calculate a second characteristic value for the acquired source of the wireless frame, which is a characteristic value specific to the transmission path between the transmitter and receiver of the wireless frame, based on the signal Sig_IQ when the header data is present, and store the second characteristic value in association with a source among the Z sources stored in the memory unit that matches the source of the wireless frame acquired from the header data.

14. 14. The program for causing a computer to execute the program described in claim 13, wherein, in the storage process of the fourth step, the estimation processing unit performs a first average phase characteristic extraction process to calculate a frequency response in a transmission path between a transmitter and a receiver of the wireless frame based on the signal Sig_IQ when the header data is present, calculate an average phase characteristic by averaging the phase characteristics of the calculated frequency response for subcarriers, and calculate the second characteristic value as a pair (start sample number, average phase characteristic) of the calculated average phase characteristic and a start sample number of a preamble of the signal Sig_IQ.

15. 15. A program for causing a computer to execute the program described in any one of claims 12 to 14, wherein the estimation processing unit performs a determination process in the fourth step to determine that header data corresponding to the signal Sig_IQ detected in the third step exists when the non-overlapping time between the duration of the signal Sig_IQ and the duration of the header data in the IQ data and header data synchronized in the second step is less than a first threshold, and to determine that header data corresponding to the signal Sig_IQ detected in the third step does not exist when the non-overlapping time is longer than the first threshold.

16. In the third step, the detection processing unit ｉ (i indicates the order of sample acquisition, i = 0, 1, 2, ...) ｉ The timestamp t when the RSS first becomes equal to or greater than the second threshold. ｓｔａｒｔ from the signal strength d ｉ The signal strength d after the rss first becomes equal to or greater than the second threshold ｉ . The timestamp d when the rss first falls below the second threshold ｉ Time d until ts ｉ .ts-t ｓｔａｒｔ as the duration of the signal Sig_IQ, and output the duration of the signal Sig_IQ thus obtained to the estimation processing unit; 16. A program for causing a computer to execute the program described in claim 15, wherein in the fourth step, when the estimation processing unit receives the duration of the signal Sig_IQ from the detection processing unit, the estimation processing unit calculates the non-overlapping time based on the duration of the signal Sig_IQ and the duration of the header data, and performs the judgment processing based on the calculated non-overlapping time.

17. 17. The program for causing a computer to execute the program according to claim 12, wherein the estimation processing unit, in the estimation processing of the fourth step, calculates a frequency response in a transmission path between a transmitter and a receiver of the wireless frame based on a preamble of the signal Sig_IQ when the header data is not present, performs processing to prevent a phase difference between adjacent subcarriers from exceeding π with respect to the phase characteristic of the calculated frequency response, thereby acquiring a phase characteristic of the frequency response in which the phase difference between the adjacent subcarriers is π or less, averages the phase characteristics of the acquired frequency response for subcarriers to calculate an average phase characteristic, and executes second average phase characteristic extraction processing to obtain a pair of the calculated average phase characteristic and a start sample number of the preamble (start sample number, average phase characteristic) as the first characteristic value.

18. 18. The program for causing a computer to execute the program according to claim 17, wherein the estimation processing unit, in the second average phase characteristic extraction process of the fourth step, obtains the frequency response by dividing a calculation result obtained by fast Fourier transforming a Long Training Field portion of a preamble of frame j consisting of the signal Sig_IQ detected in the third step by a calculation result obtained by fast Fourier transforming a Long Training Field portion of a preamble of a frame consisting of a known signal.

19. 19. A program for causing a computer to execute the program described in claim 17 or 18, wherein the estimation processing unit, in the second average phase characteristic extraction process of the fourth step, further determines whether or not the first sample number of a preamble has been identified for the signal Sig_IQ detected in the third step, and when it determines that the first sample number has been identified, obtains the set (start sample number, average phase characteristic) as the first characteristic value.

20. 20. The program for causing a computer to execute the program according to claim 19, wherein the estimation processing unit terminates the estimation processing when it determines in the fourth step that the first sample number could not be identified in the second average phase characteristic extraction processing.

21. The first characteristic value is the starting sample number s of frame j of the signal Sig_IQ detected in the third step. ｊ１ and the average phase characteristic m ｊ１ It consists of In the estimation process of the fourth step, the estimation processing unit calculates the starting sample number and the average phase characteristic obtained in the second average phase characteristic extraction process as s ｊ１ , m ｊ１ and a set of characteristic values (s ｊ , m ｊ ) is processed to change the order of addition to the storage unit to the set of characteristic values (s ｊ , m ｊ ) as a set of characteristic values (s ｋ , m ｋ )(k=1,2,...,n ｆｉｆｏ (n ｆｉｆｏ is the maximum number of characteristic values that can be stored in association with one source. ｋ =s ｋ＋１ -s ｋ (k=1,2,...,N(=n ｆｉｆｏ -1)) is an explanatory variable, and y ｋ = m ｋ＋１ -m ｋ (k=1,2,...,N(=n ｆｉｆｏ The phase change rate β is the slope of the regression function with the objective function １ and performing a phase change rate estimation process to obtain the phase change rate β １ The most recent characteristic value (s ｊ０ , m ｊ０ ) and the characteristic value (s ｊ１ , m ｊ１ ) and the error e ｕ for all Z transmission sources stored in the storage unit to obtain Z errors, and estimates the transmission source that obtains the smallest error among the obtained Z errors as the transmission source of the wireless frame.

22. 22. The program to be executed by a computer according to claim 21, wherein, in the estimation process of the fourth step, when the minimum error is equal to or less than a third threshold, the estimation processing unit further estimates the source when the minimum error equal to or less than the third threshold is obtained as the source of the wireless frame.

23. A computer-readable recording medium on which the program according to any one of claims 12 to 22 is recorded.

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