JP2020141316A - Radio wave identification device, radio wave identification method, and radio wave environment visualization system - Google Patents

Abstract

To compensate for individual differences in time information at each receiving node.SOLUTION: From among first and second received signal sequences received by first and second receiving nodes, while the scale of a time axis of the second received signal sequence is expanded and contracted at the time expansion/contraction rate, the correlation value with the first received signal sequence is calculated, the second received signal sequence is offset on the time axis by a time offset to determine the expansion/contraction rate and the time offset at which the correlation value becomes the maximum value, packets of the first and second received signal sequences are compared with each other by applying the time expansion/contraction rate and the time offset at which the correlation value becomes the maximum value to time information of the second received signal sequence, and packets having similar transmission start times of the packets, packet lengths, and signal strengths are associated with each other on a one-to-one basis, and when the maximum correlation value exceeds a threshold, the associated packet outputs a radio wave identification result determined to be a received signal sequence of radio waves received by the first and second receiving nodes from the same transmission source.SELECTED DRAWING: Figure 5

Description

The present invention relates to a radio wave identification device, a radio wave identification method, and a radio wave environment visualization system.

For example, when constructing a new wireless system, the usage status of radio waves is investigated in advance in order to confirm that interference and interference are not given to the existing wireless system or received from the existing wireless system. .. In addition, even if communication is not delivered or a problem occurs during operation of the wireless system, the usage status of radio waves will be investigated in order to identify the cause of the problem.

In order to investigate the usage status of radio waves, a radio wave environment visualization technology that visualizes the usage status of radio waves has been proposed. By utilizing the radio wave environment visualization technology, it is possible to create a heat map in which the received signal strength (RSSI: Received Signal Strength Indicator) and the traffic level of radio waves for each location are expressed in colors, for example. In addition, by displaying the location information and ID information of the transmitting station on the heat map, it can be used for investigating the surrounding radio wave environment and identifying the cause of the problem.

In order to create a heat map, receiving nodes are installed in multiple spatially separated locations, and the radio waves (for example, packets) received by each receiving node are transmitted from the same transmitting station. It determines whether or not there is one, and estimates the position of the transmitting station. The process of determining whether or not the radio wave received by each receiving node is transmitted from the same transmitting station is, for example, a process of identifying the same radio wave received by a plurality of different receiving nodes.

However, since the internal clocks of the receiving nodes individually installed in a plurality of locations are independent of each other, the time information (for example, time stamp) given to the received radio waves by the internal clocks of the plurality of receiving nodes is different. Occurs and does not match. Therefore, it is difficult to associate a plurality of radio waves using RSSI time series data measured by a plurality of receiving nodes.

The mechanism by which the difference occurs in the time information will be described with reference to FIGS. 1 and 2. FIG. 1 is a diagram showing an example of a radio wave environment visualization system. The radio wave environment visualization system 1 shown in FIG. 1 has a transmitting station 2, receiving nodes 3A and 3B, and a server 4. In this example, TIME _TX is the transmission time information at the transmitting station 2, Dist # 1 is the distance between the transmitting station 2 and the receiving node 3A, TIME _{RX # 1} is the receiving time information at the receiving node 3A, and TIME _{RX # 2} is. The reception time information in the reception node 3B, Dist # 2, indicates the distance between the transmission station 2 and the reception node 3B. Further, TIME # 1 indicates the reception time information output by the reception node 3A, and TIME # 2 indicates the reception time information output by the reception node 3B. Here, when the speed of light is expressed by c, the relationship c (TIME _{RX # 1} −TIME _TX ) = Dist # 1 and c (TIME _{RX # 2} −TIME _TX ) = Dist # 2 holds. However, since there is a difference in the processing speeds of the individual receiving nodes 3A and 3B, TIME _{RX # 1} ≠ TIME # 1 and TIME _{RX # 2} ≠ TIME # 2.

FIG. 2 is a diagram illustrating a mechanism for generating the above-mentioned time stamp difference. FIG. 2 shows the correct answer reception signal and the correct answer reception time TIME _{RX # 1,} TIME _{RX # 2} , the reception time information of the reception node 3A (hereinafter, also referred to as “time stamp”) TIME # 1, and the time stamp TIME # of the reception node 3B. The signals of the receiving nodes 3A and 3B that arrived at 2 and the server 4 are shown. In FIG. 2, t indicates the correct answer reception time, t _A indicates the time at the receiving node 3A, t _B indicates the time at the receiving node 3B, and t _S indicates the time at the server 4 on the same arbitrary unit time axis. In FIG. 2, a difference occurs in the determination result of the packet reception time determined by the internal clocks of the reception nodes 3A and 3B that are independent of each other. Therefore, there is an error of, for example, 10 ^-3 ppm between the time stamps TIME # 1 and TIME # 2 given to the same signal and the time TIMERX # 1 and TIMERX # 2 when the signal was actually received. Occurs. As a result, a difference occurs in the time information of the signal that arrives at the server 4. Therefore, it is desirable to absorb and compensate for the difference in time stamps generated by such a mechanism.

A system that finds the point where the correlation value between the template waveform data generated from the reception frame of the signal transmitted from the reference transmitter and the actual reception waveform data is maximized in multiple receivers that are not time-synchronized is proposed. (See, for example, Patent Document 1). In this proposed system, the time stamp when the correlation value of the actual received waveform data is maximized is recorded, and the reception time difference at each receiver is obtained. Further, the position of the transmitter is estimated by a position computer higher than the receiver, and the positions are estimated in the same manner for a plurality of transmitters and receivers. However, this proposed system has a configuration intended for transmitter positioning. Therefore, it does not have a function of synchronizing time information with high accuracy so that signals received by each receiver can be identified. In other words, since different delays occur according to different distances from each receiver to the higher-level position calculator, the position calculator is an individual time stamp with high accuracy that can link packets received by each receiver, for example. The difference cannot be compensated.

Japanese Unexamined Patent Publication No. 2014-0852005 JP-A-11-308658 JP-A-2014-045283

With the prior art, it is difficult to compensate for individual differences in time information at each receiving node.

Therefore, in one aspect, it is an object of the present invention to provide a radio wave identification device, a radio wave identification method, and a radio wave environment visualization system capable of compensating for individual differences in time information in each receiving node.

According to one proposal, the time axis of the second received signal sequence among the first received signal sequence received by the first receiving node and the second received signal sequence received by the second receiving node. The correlation value with the first received signal sequence is calculated while expanding and contracting the scale according to the time expansion / contraction rate, and the second received signal sequence is offset by the time offset on the time axis so that the correlation value becomes the maximum value. By applying the time expansion / contraction rate and the time offset for determining the time expansion / contraction rate and the time offset, and the time expansion / contraction rate and the time offset at which the correlation value becomes the maximum value to the time information of the second received signal series Each packet of the first received signal sequence and the second received signal sequence is compared with each other, and packets having similar transmission start times, packet lengths, and signal strengths of each packet are one-to-one. When the linking means to be linked with and the correlation value that becomes the maximum value exceeds the threshold value, the linked packet is the radio wave received by the first and second receiving nodes from the same source. Provided is a radio wave identification device including a determination means for outputting a radio wave identification result determined to be a received signal sequence.

According to one aspect, individual differences in time information at each receiving node can be compensated.

It is a figure which shows an example of the radio wave environment visualization system. It is a figure explaining the mechanism which the difference of a time stamp occurs. It is a figure which shows an example of the radio wave environment visualization system in 1st Example. It is a block diagram which shows an example of the hardware configuration of a personal computer. It is a flowchart explaining an example of the radio wave identification process in 1st Example. It is a flowchart explaining an example of a log data reading process. It is a flowchart explaining an example of a log data clipping process. It is a figure explaining the log data clipping process for four cases. It is a flowchart (the 1) explaining an example of a log data correlation calculation process. It is a flowchart (the 2) explaining an example of a log data correlation calculation process. It is a flowchart explaining an example of expansion / contraction ratio and offset determination processing. It is a figure explaining the compensation of the individual difference of a time stamp. It is a flowchart explaining an example of a packet association processing. It is a figure explaining an example of the association result of a normal packet. It is a figure explaining an example of the association result of the packet including an erroneous result. It is a figure explaining the correction of the packet association error. It is a flowchart explaining an example of radio wave identification result output processing. It is a figure which shows an example of the radio wave environment visualization system in 2nd Example. It is a flowchart explaining an example of the radio wave identification process in 2nd Example. It is a flowchart explaining an example of ID assembly result output processing. It is a figure which shows an example of the radio wave environment visualization system in 3rd Example. It is a flowchart explaining an example of radio wave identification processing in 3rd Example. It is a flowchart explaining an example of a radio wave environment visualization process. It is a figure which shows an example of a heat map.

Hereinafter, examples of the disclosed radio wave identification device, radio wave identification method, and radio wave environment visualization system will be described with drawings.

(First Example)
FIG. 3 is a diagram showing an example of the radio wave environment visualization system according to the first embodiment. The radio wave environment visualization system 11-1 shown in FIG. 3 includes a transmitting station 12, receiving modules 13-1 and 13-2, a server 14, and a personal computer (PC) 15. The transmission station 12 is an example of a transmission source, has a well-known configuration for wirelessly transmitting a packet of a signal series or the like via an antenna, and can be formed by, for example, a well-known transmitter. Each of the receiving modules 13-1 and 13-2 is an example of a receiving node, and has a well-known configuration of wirelessly receiving a packet or the like of a signal series transmitted from the transmitting station 12 via an antenna, for example, an internal clock. It can be formed by a well-known receiver. In this example, the receiving module 13-1 has a function of transmitting the received signal strength RSSI ₁ measured from the packet of the received signal series and the ID information of the transmitting station 12 detected from the received signal series to the server 14 together with the time information. It is a well-known Wi-Fi (registered trademark) module provided with. The Wi-Fi module measures the received signal strength RSSI ₁ from the received signal series packet by a well-known method, and the ID information of the transmitting station 12 (hereinafter, also simply referred to as “ID”) from the received signal series packet by a well-known method. Is detected. On the other hand, the receiving module 13-2 is a well-known SDR (Software Defined Radio) module having a function of transmitting the received signal strength RSSI ₂ measured by a well-known method from the packet of the received signal series to the server 14 together with the time information. is there.

The SDR module can also receive and analyze signals of standards other than Wi-Fi. Therefore, by using two types of receiving modules, a Wi-Fi module and an SDR module, for example, if there is interference or interference in the received signal of the Wi-Fi module, the reception signal of the SDR module may be used for interference or interference. The cause of the interference can be identified. However, the plurality of receiving modules included in the radio wave environment visualization system are not limited to different types of receiving modules, and may be the same type of receiving modules.

The server 14 is a general-purpose computer capable of receiving the received signal strength RSSI ₁ , ID, and time information from the receiving module 13-1, and the received signal strength RSSI ₂ and time information from the receiving module 13-2. The configuration of 14 is not particularly limited. In this example, the server 14 can form an example of a radio wave identification device. The configuration of the PC 15 is not particularly limited as long as the PC 15 can transmit, for example, a command to the server 14 and receive the radio wave identification result, the ID association result, and the like described later from the server 14. The command issued by the PC 15 includes a command for requesting a radio wave identification process, a radio wave environment visualization process, and the like, which will be described later.

FIG. 4 is a block diagram showing an example of the hardware configuration of the PC. The PC 15 shown in FIG. 4 has a CPU (Central Processing Unit) 151, a memory 152, an interface (I / F) 153, an input device 154, and a display device 155 connected by a bus 156. The CPU 151 is an example of a processor that controls the entire PC 15. The CPU 151 can execute various processes by executing the program stored in the memory 152. As will be described later, various processes executed by the CPU 151 include radio wave identification processing, radio wave environment visualization processing, and the like. The memory 152 is an example of a storage device that stores various data including a program executed by the CPU 151 and log data. The storage device may be a portable recording medium such as a CD-ROM (Compact Disk-Read Only Memory), a DVD (Digital Versatile Disk), or a USB (Universal Serial Bus) memory, a semiconductor memory such as a flash memory, or the like. Further, the storage device may be a computer-readable storage medium that stores the program. Further, the storage device may be formed of a plurality of storage devices, and in this case, the storage device may include a storage device externally connected to the PC 15.

The I / F 153 controls the exchange of information, commands, and the like between the PC 15 and the server 14. The input device 154 can be formed by a keyboard or the like operated by the operator of the PC 15, and is used for inputting information, a command, or the like into the PC 15. The display device 155 is used to display a message, a processing result, or the like to the operator. The processing result displayed by the display device 155 may include a radio wave identification result, an RSSI heat map which is an example of a radio wave environment visualization result, and the like. A touch panel in which the input device 154 and the display device 155 are integrally provided may be used.

Since the configuration of the server 14 may be the same as the configuration of the PC 15 shown in FIG. 4, the illustration and description of the configuration of the server 14 will be omitted. Various processes executed by the CPU of the server 14 include radio wave identification processes and the like.

FIG. 5 is a flowchart illustrating an example of the radio wave identification process in the first embodiment. The radio wave identification process shown in FIG. 5 can be executed by the CPU of the server 14 executing a program stored in the memory of the server 14 in response to a command requesting the radio wave identification process from the PC 15. The PC 15 issues a command requesting the radio wave identification process in response to the operation of the input device 154 by the operator. The memory of the server 14 also stores files, arrays, variables, and the like.

In FIG. 5, in step S1, the CPU of the server 14 performs a log data reading process for reading the log data of the receiving modules 13-1 and 13-2. The CPU of the server 14 records the received signal strength RSSI ₁ , ID, and time information received from the receiving module 13-1 and the received signal strength RSSI ₂ and time information received from the receiving module 13-2, respectively. Is stored in the memory of the server 14.

FIG. 6 is a flowchart illustrating an example of log data reading processing. In FIG. 6, in step S11, the CPU of the server 14 opens the log data file of the receiving module 13-1 stored in the memory of the server 14 (hereinafter, also referred to as “open”). In step S12, the CPU of the server 14 stores the log data file of the receiving module 13-1 in the array RS1. As shown in the upper right part of FIG. 6, the array RS1 contains, for example, a time stamp (hh: mm: ss) representing hours, minutes, and seconds, a packet length (μsec), and RSSI (dBm) of each packet. It is stored for indexes RS1-1 to RS1-M (M is a natural number of 2 or more). The time stamp is an example of time information given to the received radio wave by the internal clock of the receiving module by a well-known method. In step S13, the CPU of the server 14 stores the number of packets M of the array RS1 in the variable NumPktRS1.

In step S14, the CPU of the server 14 opens the log data file of the receiving module 13-2. In step S15, the CPU of the server 14 stores the log data file of the receiving module 13-2 in the array RS2. As shown in the central part on the right side of FIG. 6, the time stamp, packet length, and RSSI are stored in the array RS2 for each index RS2-1 to RS2-M. In step S16, the CPU of the server 14 stores the number of packets M of the array RS2 in the variable NumPktRS2.

In step S17, the CPU of the server 14 opens the operation setting file. As shown in the lower right part of FIG. 6 for convenience, the operation setting file includes the RSSI offset RSSI_Offset (dB) for compensating for the difference in RSSI, the scale of the time axis is expanded and contracted, and the offset on the time axis is added. Guard time for Guard_Time (sec) etc. is included. In this example, the behavior configuration file contains the minimum time offset t _offset t_begin (sec), the maximum time offset t _offset t_end (sec), and the number of loops num_t (times). In addition, the operation setting file contains the minimum value k_begin of the time expansion / contraction rate (hereinafter, also simply referred to as "expansion / contraction rate") k, the maximum value k_end of the expansion / contraction rate k, the number of loops num_k (times), and the RSSI offset RSSI_Offset (dB). Includes guard time Guard_Time (sec), etc. The operation setting file further includes the time length search_window_past (sec) of the past search window for calculating the inter-packet correlation and the time length search_window_future (sec) of the future search window for calculating the inter-packet correlation. The operation setting file contains the type correlator_type that specifies the type of correlator for correlation calculation, and the weighting coefficients w1, w2, and w3 for interpacket correlation calculation. The number of loops num_t indicates the number of times to execute loop processing with the time offset t _offset as a loop variable. The number of loops num_k indicates the number of times that loop processing is executed with the expansion / contraction rate k as a loop variable. The time length of the past search window search_window_past (sec) indicates how far back in the past the search target range is set. The time length of the future search window search_window_future (sec) indicates how far in the future the search target range should be. The weighting factor w1 is for the time stamp, the weighting factor w2 is for the packet length, and the weighting factor w3 is for RSSI. In step S18, the CPU of the server 14 stores the information of the operation setting file in the array SetD. In step S19, the CPU of the server 14 assigns the contents of the array SetD to local variables such as offset RSSI_Offset and guard time Guard_Time in the operation setting file, and the process returns to the radio wave identification process shown in FIG. 5 and proceeds to the process of step S2. move on.

In this way, the CPU of the server 14 functions as a reading means for reading the log data of the receiving modules 13-1 and 13-2 from the memory of the server 14 by executing the log data reading process of step S1.

In FIG. 5, in step S2, the CPU of the server 14 performs a log data clipping process of clipping the log data of the receiving modules 13-1 and 13-2 including the guard time Guard_Time to find the time stamp. The guard time Guard_Time is used as a margin for expanding and contracting the scale of the time axis of the time stamp, which will be described later, and offsetting on the time axis. FIG. 7 is a flowchart illustrating an example of log data clipping processing. In FIG. 7, in step S21, the CPU of the server 14 extracts the clipping timing of the data of the array RS1 and the data of the array RS2. Specifically, for example, the time stamps of the first data and the last data that arrived at the receiving module 13-2 are always wider than the time stamps of the first data and the last data that arrived at the receiving module 13-1 by the guard time Guard_Time or more. Extract the clipping timing. In step S22, the CPU of the server 14 clips the data of the array RS1 at the corresponding clipping timing and stores it in the new array NewRS1. In step S23, the CPU of the server 14 clips the data of the array RS2 at the corresponding clipping timing and stores it in the new array NewRS2. In step S24, the CPU of the server 14 stores the number of packets in the array NewRS1 in the variable NumPktNewRS1. In step S25, the CPU of the server 14 stores the number of packets in the array NewRS2 in the variable NumPktNewRS2. In step S26, the CPU of the server 14 stores the packet start time of the array NewRS2 in the variable NewRS2_Start. In step S27, the CPU of the server 14 stores the packet end time of the array NewRS2 in the variable NewRS2_Stop. In step S28, the CPU of the server 14 merges the variable NewRS2_Start and the variable NewRS2_Stop.

FIG. 8 is a diagram illustrating four cases of log data clipping processing. In FIG. 8, the data stream length of the received signal sequence is shown by hatching. In the log data clipping process, for example, the time stamps of the first data and the last data that arrived at the receiving module 13-2 are always guard time Guard_Time (sec) or more than the time stamps of the first data and the last data that arrived at the receiving module 13-1. Cut the data so that it is wide. In FIG. 8, for convenience, the time stamp of the data of the sequence _RS1 is shown by TS _RS1 , and the time stamp of the data of the sequence _RS2 is shown by TS _RS2 .

In case I shown in FIG. 8A, the time stamp of the start data of the array RS1 is later than the time stamp of the start data of the array RS2, and the time stamp of the end data of the array RS1 is the time stamp of the end data of the array RS2. Faster than the time stamp. In this case I, the time stamp of the clipped array RS1 is the same as the time stamp before clipping. On the other hand, the time stamp of the clipped array RS2 has a slower time stamp of the first data and a faster time stamp of the last data than before clipping. In addition, the time stamp of the clipped array RS2 is earlier than the time stamp of the clipped array RS1 by the guard time Guard_Time for the first data and later by the guard time Guard_Time for the last data.

In case II shown in FIG. 8 (b), the time stamps of the start data and the end data of the array RS1 are earlier than the time stamps of the start data and the end data of the array RS2, respectively. In this case II, the time stamp of the clipped array RS1 has a slower time stamp of the first data than that before clipping. On the other hand, the time stamp of the clipped array RS2 has a faster time stamp of the last data than before clipping. In addition, the time stamp of the clipped array RS2 is earlier than the time stamp of the clipped array RS1 by the guard time Guard_Time for the first data and later by the guard time Guard_Time for the last data.

In case III shown in FIG. 8C, the time stamps of the start data and the end data of the array RS1 are later than the time stamps of the start data and the end data of the array RS2, respectively. In this case III, the time stamp of the clipped array RS1 has a later time stamp of the first data and a faster time stamp of the last data than before clipping. On the other hand, the time stamp of the clipped array RS2 has a slower time stamp of the first data than before clipping. In addition, the time stamp of the clipped array RS2 is earlier than the time stamp of the clipped array RS1 by the guard time Guard_Time or faster for the first data and later than the guard time Guard_Time for the last data.

In case IV shown in FIG. 8 (d), the time stamp of the start data of the array RS1 is earlier than the time stamp of the start data of the array RS2, and the time stamp of the end data of the array RS1 is the time stamp of the end data of the array RS2. Slower than the time stamp. In this case IV, the time stamp of the clipped array RS1 has a later time stamp of the first data and a faster time stamp of the last data than before clipping. On the other hand, the time stamp of the clipped array RS2 is the same as the time stamp before clipping. In addition, the time stamp of the clipped array RS2 is earlier than the time stamp of the clipped array RS1 by the guard time Guard_Time for the first data and later by the guard time Guard_Time for the last data.

After step S28, the process returns to the radio wave identification process shown in FIG. Specifically, for steps S3 and S4 shown in FIG. 5, a loop process in which the time offset t _offset is set as a loop variable is executed for the number of loops num_t, and a loop process in which the expansion / contraction rate k is set as a loop variable is looped. Proceed to the process to execute the number of times num_k. The expansion / contraction ratio k represents the ratio of expansion / contraction of the scale on the time axis of the time stamp. The time offset t _offset represents the number of seconds for adding or subtracting the offset amount on the time axis to the absolute value of the time stamp. Loop processing with the time offset t _offset as the loop variable is executed for the number of loops num_t while changing the loop step parameter t_step = (t_end-t_begin) / num_t) in the range of t_begin to t_end. Further, the loop processing using the expansion / contraction rate k as the loop variable is executed by the number of loops num_k while changing the loop step parameter k_step = (k_end-k_begin) / num_t) in the range of k_begin to k_end.

In this way, the CPU of the server 14 performs the log data clipping process to clip the log data of the receiving modules 13-1 and 13-2 including the guard time Guard_Time to cue the time stamp. Functions as a means. The time information of the first data and the last data of the second received signal sequence received by the receiving module 13-2 is always more than the time information of the first data and the last data of the first received signal sequence received by the receiving module 13-1. Guard time is wider than Guard_Time.

In FIG. 5, in step S3, the CPU of the server 14 performs a log data correlation calculation process for calculating the log data correlation. 9 and 10 are flowcharts illustrating an example of log data correlation calculation processing. In FIG. 9, in step S301, the CPU of the server 14 calculates the loop step parameters k_step and t_step. In step S302, the CPU of the server 14 resets the loop counter num_loop. In step S303, the CPU of the server 14 resets the maximum correlation value holding variable sigma_correlation_max that holds the maximum value of the correlation value corr (k, t _offset ) in the k, t _offset loop. The k, t _offset loop includes a loop process that executes a loop process with the time offset t _offset as a loop variable for the number of loops num_t, and a process for executing a loop process with the expansion / contraction rate k as a loop variable for the number of loops num_k. The correlation value corr (k, t _offset ) is the sum of the correlation values of the array and the array (for example, array RS1 and array RS2) in a certain [k, t _offset ] combination. In step S304, the CPU of the server 14 resets the maximum value holding variables k_at_max and t_at_max. The maximum value holding variable k_at_max is a variable that holds the value of the expansion / contraction rate k when the correlation value corr (k, t _offset ) takes the maximum value. The maximum value holding variable t_at_max is a variable that holds the value of the time offset t _offset when the correlation value corr (k, t _offset ) takes the maximum value.

Next, the processing of steps S305 to S314, the processing of executing the loop processing of the loop variable array RS12 of steps S315 to S322 for NumRS12 minutes, and the processing of steps S323 to S326 are performed with the expansion / contraction ratio k and the time offset t _offset k, The process proceeds to execute only the t _offset loop.

In FIG. 9, in step S305, the CPU of the server 14 calculates the expansion / contraction rate k in the k, t _offset loop. In step S306, the CPU of the server 14 calculates the time offset t _offset in the k, t _offset loop. In step S307, the CPU of the server 14 declares and initializes the loop variable array RS12. In step S308, the CPU of the server 14 applies the stretch ratio k and the time offset t _offset to the new array NewRS1. In step S309, the CPU of the server 14 stores the packet start time of the array NewRS1 in the variable NewRS1_Start, and stores the packet end time of the array NewRS1 in the variable NewRS1_Stop. In step S310, the CPU of the server 14 clears the variables NewRS1_Start and NewRS1_Stop. In step S311 the CPU of the server 14 merges the variable NewRS1 and the variable NewRS2 and stores them in the loop variable array RS12. In step S312, the CPU of the server 14 sorts the loop variable array RS12 by the time stamp. In step S313, the CPU of the server 14 stores the number of packets in the loop variable array RS12 in the variable NumRS12. In step S314, the CPU of the server 14 resets the in-loop variables of the loop of the loop variable array RS12, and the process proceeds to step S315 shown in FIG.

In FIG. 10, in step S315, the CPU of the server 14 stores the value of the loop variable array RS12 in the loop in-loop variable of the loop variable array RS12. In step S316, the CPU of the server 14 stores the packet length of each packet of the loop variable array RS12 in the variable time_duty. In step S317, the CPU of the server 14 resets the maximum correlation value holding variable sigma_correlation_max. In step S318, the CPU of the server 14 sets the flag of the array RS1 or the array RS2 for each packet of the loop variable array RS12, and indexes each of the receiving modules 13-1 and 13-2 for each packet of the loop variable array RS12. Is given. The flag indicates that each packet in the loop variable array RS12, which merges the variable NewRS1 and the variable NewRS2, is array RS1 or array RS2. In step S319, the CPU of the server 14 records the result of the loop variable array RS12 in the variable RS12Record. In step S320, the CPU of the server 14 calculates a correlation value based on the difference between the RSSIs of the array NewRS1 and the array NewRS2 for each time stamp delimiter with an event. Here, the event means a transition of data of two received signal sequences, that is, a rising edge or a falling edge. In step S321, the CPU of the server 14 integrates the correlation values calculated in the previous stage and stores them in the variable SigmaCorr. In step S322, the CPU of the server 14 records the variable SigmaCorr in the variable RS12CorRecord. In step S323, the CPU of the server 14 clears the loop variable array RS12. In step S324, the CPU of the server 14 records in the variable SigmaCorrMax that the maximum value of the variable SigmaCorr exceeds the threshold value. By excluding the variable SigmaCorr whose maximum value is equal to or less than the threshold value, it is possible to exclude a low correlation value even if it is the maximum value, so that it is possible to prevent the correlation of noise components and the like from being determined, for example. In step S325, the CPU of the server 14 stores the maximum correlation value holding variables k_at_max and t_at_max when the variables are SigmaCorrMax in the array CorrRecord. In step S326, the CPU of the server 14 increments the loop variable NumLoop, which represents the number of k, t _offset loops.

As a result, the processing of steps S305 to S314 shown in FIG. 9, the processing of executing the processing of steps S315 to S322 shown in FIG. 10 for the loop of the loop variable array RS12, and the processing of steps S323 to S326 shown in FIG. 10 are performed. After executing the k and t _offset loops of the expansion / contraction rate k and the time offset t _offset , the process returns to the radio wave identification process shown in FIG. 5 and proceeds to the process of step S4.

In FIG. 5, in step S4, the CPU of the server 14 performs the expansion / contraction rate and the offset determination process for determining the expansion / contraction rate and the time offset at which the correlation value becomes the maximum value exceeding the threshold value. FIG. 11 is a flowchart illustrating an example of expansion / contraction ratio and offset determination processing. In FIG. 11, in step S41, the CPU of the server 14 reads out the maximum correlation value holding variables k_at_max and t_at_max stored in the array CorrRecord. In step S42, the CPU of the server 14 determines the maximum correlation value holding variable k_at_max at the end of the k, t _offset loop as the optimum expansion / contraction rate k. Further, in step S42, the CPU of the server 14 determines the maximum correlation value holding variable t_at_max at the end of the k, t _offset loop as the optimum time offset t _offset . After step S42, the process returns to the radio wave identification process shown in FIG.

As a result, with respect to the processes of steps S3 and S4 shown in FIGS. 9 to 11, the process of executing the loop process with the time offset t _offset as the loop variable for the number of loops num_t is performed with the expansion / contraction rate k as the loop variable. Execute the process for the number of loops num_k. After that, the process proceeds to the process of step S5 shown in FIG.

In this way, the CPU of the server 14 functions as a determination means for determining the time expansion / contraction rate k at which the correlation value becomes the maximum value and the time offset t _offset by executing the processes of steps S3 and S4. The determining means is the first of the first and second received signal sequences received by the receiving modules 13-1 and 13-2, while expanding and contracting the scale of the time axis of the second received signal sequence with the time expansion / contraction rate k. Calculate the correlation value with the received signal series. Further, the determining means offsets the second received signal sequence by the time offset t _offset on the time axis to determine the time expansion / contraction rate k at which the correlation value becomes the maximum value and the time offset t _offset . Further, the determination means determines the time expansion / contraction rate k at which the correlation value becomes the maximum value and the time offset t _offset from the time series data extracted by the extraction means.

Therefore, in this example, the individual difference of the time stamp in each of the receiving modules 13-1 and 13-2 can be compensated as follows. First, the server 14 calculates the correlation while expanding and contracting the scale of the time axis of the received signal series from one of the receiving modules so that the characteristics of the received signal series received from the receiving modules 13-1 and 13-2 are similar. To do. The characteristics of the received signal sequence are the transmission start time, packet length, RSSI, and the like of the packet included in the received signal sequence. At the same time, the correlation is calculated while offsetting the received signal sequence from the one receiving module on the time axis. The offset on the time axis of the received signal sequence means that the received signal sequence with the scale of the time axis expanded or contracted is slid on the time axis by the time offset in at least one direction (positive direction or negative direction). Thereby, the expansion / contraction rate k and the time offset t _offset on the time axis whose characteristics of the received signal sequence from one receiving module are most similar to the characteristics of the received signal sequence from the other receiving module can be determined. That is, the expansion / contraction rate k and the time offset t _offset of the time axis at which the correlation value of the two received signal sequences received from the receiving modules 13-1 and 13-2 becomes the maximum value exceeding the threshold value are determined, and these two received signals are received. The series can be synchronized.

FIG. 12 is a diagram illustrating compensation for individual differences in time stamps. The process shown in FIG. 12 includes procedures ST1 to ST3 corresponding to steps S3 and S4 shown in FIG. 5 executed by the CPU of the server 14. In the procedure ST1, the correlation value of the received signal series of the receiving module 13-1 and the receiving module 13-2 is calculated, for example, every time t _s . For example, time t _s = 30 (sec). In step ST2, if the correlation value is not 0, the time axis (width) of the time stamp of the receiving module 13-2 is multiplied by the expansion / contraction rate k, the time offset t _offset is added, and the correlation value at that time is re-established. calculate. Here, the expansion / contraction rate k is a positive real number that is not 0, and the time offset t _offset is a real number. In the procedure ST3, the expansion / contraction rate k and the time offset t _{offset at} which the correlation value becomes the maximum value exceeding the threshold value are obtained. Specifically, in the procedure ST3, the process of the previous procedure ST2 is repeated while changing the expansion / contraction ratio k and the time offset t _offset .

As a result, the correlation value of the received signal sequence of the receiving module 13-2 that arrived at the server 14 with the received signal sequence of the receiving module 13-1 that arrived at the server 14 exceeds the threshold value, as shown in the lower part of FIG. The individual difference of the time stamp is corrected so that it becomes the maximum value. Specifically, the scale of the received signal series of the receiving module 13-1 is expanded and contracted by the expansion / contraction rate k, and is slid in at least one direction (positive direction or negative direction) by the time offset t _offset on the time axis. .. In FIG. 12, the positive direction on the time axis is the right direction, and the negative direction is the left direction. Since FIG. 12 is a schematic diagram, the amplitude of each received signal sequence does not represent RSSI on the same scale.

In this way, the correlation value is calculated while expanding and contracting the scale of the time axis of the time stamps given to the received signal series received by the plurality of receiving modules according to the expansion / contraction rate k, and at the same time, according to the time offset t _offset on the time axis. The correlation value is calculated while offsetting the received signal sequence. Thereby, the expansion / contraction rate k of the scale on the time axis and the time offset t _offset on the time axis can be determined so that the correlation value becomes the maximum value exceeding the threshold value.

In the packet linking process, the expansion / contraction rate k and the time offset t _offset at which the correlation value calculated as described above becomes the maximum value exceeding the threshold value are applied to the time stamp of the receiving module 13-2, so that each receiving module 13- The same packets received by 1, 13-2 are linked to each other. Specifically, each packet of the received signal sequence of the receiving module 13-1 and the received signal sequence of the receiving module 13-2 is compared with each other, and the transmission start time, packet length, and RSSI of each packet are compared. Associate similar packets on a one-to-one basis. In addition, if the reception order of the packet candidates for linking is different, or if there is an error in the linking of packets, such as multiple packets being duplicated, the packet order will be changed by shaking as described later. Correct the error in packet association by applying the rule that there is no packet.

In FIG. 5, in step S5, the CPU of the server 14 performs a packet linking process for linking packets. FIG. 13 is a flowchart illustrating an example of the packet linking process. In the packet linking process shown in FIG. 13, the processes of steps S51 to S53 and the processes of steps S54 to S59 are executed for the loops of the array NewRS2 for the loops of the array NewRS1.

In FIG. 13, in step S51, the CPU of the server 14 stores the value of the array NewRS1 in the in-loop variable of the loop of the array NewRS1. In step S52, the CPU of the server 14 applies the optimum values of the expansion / contraction rate k and the time offset t _offset to the array NewRS1 and stores them in the variable NewRS1Fix. In step S53, the CPU of the server 14 resets the variable MaxCorr that stores the maximum value of the correlation value.

In step S54, the CPU of the server 14 stores the value of the array NewRS2 in the variable in the loop of the array NewRS2. In step S55, the CPU of the server 14 calculates the correlation value using the difference information of the packet of the variable NewRS1Fix and the packet of the array NewRS2 and stores it in the variable Corr. At this time, one of the received signal sequences whose scale on the time axis is expanded or contracted is offset on the time axis, the two received signal sequences are linked, and then the process of linking again by shaking is also performed. Shaking is a process of correcting an error in packet association by swinging (shifting) the received signal sequence in both directions (positive direction and negative direction) by a certain range on the time axis to make fine adjustments. In step S57, the CPU of the server 14 records the maximum value of the variable Corr in the variable MaxCorr, and records the index of the array NewRS2 when the variable Corr becomes the maximum value in the variable NewRS2Index. In step S58, the CPU of the server 14 stores the value of the variable Corr in the variable MemCorr. In step S59, the variables NewRS1Index and NewRS2Index (that is, the associated result) when the variable MaxCorr is stored are stored in the array Identified. The array Identified shows the association result including the variables NewRS1Index, NewRS2Index, the source address of the transmitting station 12, and the like, which will be described later.

In this way, the CPU of the server 14 functions as a linking means for linking packets by executing the packet linking process in step S5. The associating means applies the time expansion / contraction rate k at which the correlation value becomes the maximum value and the time offset t _offset to the time information of the second received signal sequence, so that the first received signal sequence and the second received signal sequence Compare each packet of each of them. Further, the linking means links packets having similar transmission start times, packet lengths, and signal strengths of each packet on a one-to-one basis. The associating means shakes when the receiving order of the packets of the associating candidate is different, or when multiple packets are duplicated, and the order of the packets is not changed. Apply to correct packet association errors. Shaking corrects an error in packet linking by shaking the packet of the linking candidate by a certain range on the time axis and making fine adjustments.

FIG. 14 is a diagram illustrating an example of a normal packet association result. FIG. 14 shows the received signal sequences of the receiving module 13-1 and the receiving module 13-2 after compensating for the individual difference of the time stamp. In each received signal sequence, the packets are represented by rectangles, and FIG. 14 compares the packets of the receiving module 13-1 and the receiving module 13-2 by the transmission start time, the packet length, and RSSI, and all the comparisons are made. An example of successfully linking packets with similar elements is shown. Correctly linked packets are indicated by dashed arrows.

FIG. 15 is a diagram illustrating an example of a packet association result including an erroneous result. FIG. 15 shows a received signal sequence in which an error in packet association occurs when a packet reception defect occurs in the receiving module 13-1 due to the arrangement of the receiving module 13-1 or the reception sensitivity. Shown. Since some packets are missing in the receiving module 13-1 as shown by the broken line rectangle, the packets having similar elements to all the compared elements are changed, and as a result, the packet association error occurs. An example is shown. Correctly linked packets are indicated by dashed arrows. In addition, packets that are erroneously linked are indicated by arrows on the alternate long and short dash line.

FIG. 16 is a diagram illustrating correction of packet association error. FIG. 16 shows an example of correcting an error in associating the packets shown in FIG. As shown in FIG. 16A, when the reception order of the packets of the linkage candidate is different, or when duplicate association occurs in a plurality of packets, the order of the packets is not changed. Apply the rule to correct the packet association error. Specifically, as shown in FIG. 16B, the position of the packet of the association candidate of the receiving module 13-2 is shaken on the time axis. Then, as shown in FIG. 16 (c), packets having the highest correlation under the condition that the reception order is changed and duplicate association does not occur, that is, the packets having the maximum correlation value exceeding the threshold value are associated with each other. ..

In the above example, correction of packet association error has been described for the case where packet reception loss occurs in the receiving module 13-1, but the receiving module 13-1 receives an extra packet due to noise or the like. In some cases. In this case, since the extra packet caused by noise or the like can be detected by a well-known method, the detected extra packet can be excluded and the packet association error can be corrected in the same manner as described above. Further, when a packet reception defect occurs in both reception modules 13-1 and 13-2, or when an extra packet due to noise or the like is received, the packet association error is the same as described above. Can be corrected to.

Even if the reception order of the received packets associated with the packet association is changed due to the difference in the processing time of each receiving module, the conventional technology cannot detect such a change in the receiving order of the received packets.

On the other hand, according to this embodiment, one of the received signal sequences whose scale on the time axis is expanded or contracted is offset (sliding) on the time axis, the two received signal sequences are linked, and then the strings are linked again by shaking. Perform the process of attaching. By shaking, it is possible to change the reception order and link the packets with the highest correlation under the condition that duplicate linking does not occur, so that it is possible to correct the packet linking error.

In FIG. 13, after the processing of steps S51 to S53 and the processing of steps S54 to S59 are executed for the loop of the array NewRS2 for the loop of the array NewRS1, the processing returns to the radio wave identification process shown in FIG. Then, the process proceeds to step S6.

In FIG. 5, in step S6, the CPU of the server 14 performs radio wave identification result output processing for outputting the radio wave identification result to the PC 15. FIG. 17 is a flowchart illustrating an example of radio wave identification result output processing. In FIG. 17, in step S61, the CPU of the server 14 reads the value of the array Identified. In step S62, the CPU of the server 14 determines that the variables NewRS1Index and NewRS2Index described in the same line of the array Identified are associated packets, outputs the radio wave identification result to the PC 15, and the process is shown in FIG. The process returns to the radio wave identification process, and the radio wave identification process ends. In the PC 15, the CPU 151 displays the radio wave identification result from the server 14 on, for example, the display device 155.

In this way, the CPU of the server 14 functions as a determination means for outputting the radio wave identification result to the PC 15 by executing the radio wave identification result output process in step S6. When the correlation value that becomes the maximum value exceeds the threshold value, the determination means determines that the associated packet is a reception signal sequence of radio waves received by the first and second receiving nodes from the same transmission source. Output the radio wave identification result.

According to the first embodiment, it is possible to compensate for individual differences in time stamps in each receiving module.

(Second Example)
FIG. 18 is a diagram showing an example of the radio wave environment visualization system in the second embodiment. In FIG. 18, the same parts as those in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted. The radio wave environment visualization system 11-2 shown in FIG. 18 includes a transmitting station 12, receiving modules 13-1 and 13-2, a server 14, and a PC 15. At least one of the receiving modules 13-1 and 13-2 has a function of transmitting the ID of the transmitting station 12 to the server 14. In the second embodiment, the server 14 responds to the command requesting the radio wave identification process including the ID association from the PC 15, and the signal reception intensities RSSI ₁ and RSSI ₂ measured by the reception modules 13-1 and 13-2. Is associated with, that is, associated with the ID of the transmitting station 12. In response to the operation of the input device 154 by the operator, the PC 15 issues a command requesting radio wave identification processing including ID association. The ID of the transmitting station 12 is detected by the receiving module 13-1 in this example. Further, the server 14 outputs the radio wave identification result and the ID association result to the PC 15.

FIG. 19 is a flowchart illustrating an example of the radio wave identification process in the second embodiment. In FIG. 19, the same steps as those in FIG. 5 are designated by the same reference numerals, and the description thereof will be omitted. In this example, since the server 14 receives the command requesting the radio wave identification process including the ID association from the PC 15, the process proceeds to step S7 after step S6. A step of determining whether or not the command requesting the radio wave identification process includes ID association is provided, and the process proceeds to step S7 only when the determination result is YES, and step S7 when the determination result is NO. May end the process after step S6 without executing. In FIG. 19, in step S7, the CPU of the server 14 transfers the ID association result of the signal reception intensities RSSI ₁ and RSSI ₂ received from the reception modules 13-1 and 13-2 to the ID of the transmission station 12 to the PC 15. The ID association result output process to be output is performed, and the process ends.

FIG. 20 is a flowchart illustrating an example of ID assembly result output processing. In FIG. 20, in step S71, the CPU of the server 14 reads the value of the array Identified. In step S72, the CPU of the server 14 determines that the packet is associated with the variables NewRS1Index and NewRS2Index described in the same line of the array Identified. In step S73, the CPU of the server 14 determines that the ID is associated with MAC (Media Access Control) information, which is an example of the source address of the transmitting station 12, described in the same line as the variable NewRS2Index of the array Identified. Then, the ID association result is output to the PC 15. After step S73, the process returns to the radio wave identification process shown in FIG. 5, and the radio wave identification process ends. The MAC information of the transmitting station 12 is an example of the source address (or source address) information. In the PC 15, the CPU 151 displays the radio wave identification result from the server 14 and the ID association result on, for example, the display device 155.

In this way, the CPU of the server 14 executes the ID association result output process in step S7 to receive the signal reception strengths RSSI ₁ and RSSI ₂ and the transmission station 12 received from the reception modules 13-1 and 13-2. It functions as an output means for outputting the ID association result with the ID of. The output means is an ID linking result in which the radio wave identification result and the ID information of the transmitting station 12 detected by the receiving module 13-1 or the receiving module 13-2 are linked to the reception strength of the first and second received signal sequences. And output.

According to the second embodiment, it is possible to compensate for the individual difference of the time stamp in each receiving module, and it is possible to associate the received signal strength of the radio wave for each place with the source address information.

(Third Example)
By the way, by repeating the radio wave identification process of the first embodiment shown in FIG. 5 for each receiving module pair, the above radio wave is provided even when three or more receiving modules are provided as in the third embodiment. The identification process can be extended. The process of compensating for individual differences in time stamps and the process of linking packets are processes performed between two receiving modules. By repeating the same processing as these processing between two receiving modules of different combinations, it is possible to compensate for individual differences in the time stamps of three or more receiving modules and associate packets.

FIG. 21 is a diagram showing an example of the radio wave environment visualization system according to the third embodiment. In FIG. 21, the same parts as those in FIGS. 3 and 18 are designated by the same reference numerals, and the description thereof will be omitted. The radio wave environment visualization system 11-3 shown in FIG. 21 includes a transmitting station 12, receiving modules 13-1 to 13-n (n is a natural number of 3 or more), a server 14, and a PC 15. In this example, the receiving modules 13-2 to 13-n other than the receiving module 13-1 are SRD modules. In the third embodiment, when the command requesting the radio wave identification process from the PC 15 includes ID association, the server 14 has the signal reception strength measured by the pair of reception modules and the transmission station detected by a certain reception module. It associates with, that is, associates with 12 IDs. In this example, a receiving module is a receiving module 13-1. Then, the server 14 performs such ID association for the signal reception strength measured by each reception module pair such as a pair of adjacent reception modules, and finally, the radio wave identification result and the radio wave identification result for all the reception modules. / Or the ID association result is output to the PC15. That is, the server 14 can output at least one of the radio wave identification result and the ID association result to the PC 15.

FIG. 22 is a flowchart illustrating an example of the radio wave identification process in the third embodiment. In FIG. 22, in step S1-1, the CPU of the server 14 reads the log data of the pair of receiving modules 13-1 and 13-2, and performs the same processing as in steps S2 to S4 shown in FIG. 5, for example. In step S7-1, the CPU of the server 14 associates the signal reception strength RSSI ₁ received from the reception module 13-1 with the signal reception strength RSSI ₂ received from the reception module 13-2 with the ID of the transmission station 12. The ID association result output processing for outputting the attachment result is performed. The process of step S7-1 is, for example, the same as the process of step S5 shown in FIG. In FIG. 22, for example, “1 & 2” described in step S7-1 is an ID association result output process for outputting the ID association result of the signal reception strength RSSI ₁ and RSSI ₂ with the ID of the transmitting station 12. Show that. Similarly, for example, “n-1 & n” described in step S7-n-1 described later is an ID that outputs the ID association result of the signal reception intensities RSSI _n-1 and RSSI _n with the ID of the transmitting station 12. Indicates that the linking result output processing is performed. The ID association result output process may be the same as the ID association result output process described with reference to FIG. 20, for example.

Next, in step S1-2, the CPU of the server 14 reads the log data of the pair of receiving modules 13-2 and 13-3, and performs the same processing as in steps S2 to S4 shown in FIG. 5, for example. In step S7-2, the CPU of the server 14 links the signal reception strength RSSI ₂ received from the reception module 13-2 and the signal reception strength RSSI ₃ received from the reception module 13-3 with the ID of the transmission station 12. The ID association result output processing for outputting the attachment result is performed. The process of step S7-2 is the same as the process of step S5 shown in FIG. 5, for example. Hereinafter, the above processing is repeated, and in step S1-n-1, the CPU of the server 14 reads the log data of the pair of receiving modules 13-n-1, 13-n, and for example, steps S2 to 2 shown in FIG. The same process as in S4 is performed. In step S7-n-1, the CPU of the server 14 transmits the signal reception strength RSSI _n-1 received from the reception module 13-n _-1 and the signal reception strength RSSI _n received from the reception module 13-n. The ID association result output process for outputting the ID association result with the ID of is performed. The process of step S7-n-1 is, for example, the same as the process of step S5 shown in FIG. Next, in step S7-n, the CPU of the server 14 merges the radio wave identification results obtained by performing the same processing as in step S6 shown in FIG. 5 for the signal reception strength measured by each pair of reception modules. Further, in step S7-n, the CPU of the server 14 merges the ID association results obtained for the signal reception strength measured by each pair of reception modules. Further, in step S7-n, the CPU of the server 14 transfers the merged radio wave identification result and / or the merged ID association result to the radio wave identification results and / or IDs of all the receiving modules 13-1 to 13-n. Output to PC15 as the linking result.

In this way, the CPU of the server 14 executes the process shown in FIG. 22, and the receiving signal sequence received by the three or more receiving modules 13-1 to 13-n by the determining means and the associating means. Among the received signal sequences received by each receiving module pair, the processing for the first and second received signal sequences is repeated. In addition, the determination means merges the radio wave identification results for each receiving node pair.

According to the third embodiment, the radio wave identification process can be extended even when three or more receiving modules are provided. Further, if necessary, it is possible to compensate for individual differences in time stamps in each receiving module, and to associate the received signal strength of radio waves for each location with the source address information. Further, since a plurality of ID association results are merged, the accuracy of the ID association results can be improved.

(Fourth Example)
Next, a fourth embodiment will be described. In the fourth embodiment, the radio wave environment visualization process is performed based on the radio wave identification result output in any of the first to third embodiments.

FIG. 23 is a flowchart illustrating an example of the radio wave environment visualization process. The radio wave environment visualization process shown in FIG. 23 can be executed, for example, by the CPU 151 of the PC 15 executing a program stored in the memory 152. To start the radio wave environment visualization process shown in FIG. 23, for example, the operator of the PC 15 operates the input device 154 to issue a command requesting the radio wave environment visualization process.

In FIG. 23, in step S91, the CPU 151 of the PC 15 transmits a command requesting the radio wave identification process to the server 14 in response to the command requesting the radio wave environment visualization process. Further, in step S91, the CPU 151 of the PC 15 receives the radio wave identification result output from the server 14 in response to the transmitted command requesting the radio wave identification process. In step S92, the CPU 151 of the PC 15 creates a heat map in which the received signal strength (RSSI) of the radio wave for each location of the receiving module and the traffic level are expressed in color based on the radio wave identification result output. For the heat map creation itself, for example, a well-known method can be adopted. Further, if there is a receiving module (for example, receiving module 13-1) that outputs the ID of the transmitting station 12, for example, the ID received by the server 14 is displayed on the heat map to display the surrounding radio wave environment. It can be used for investigation and identification of the cause of defects. In step S93, the CPU 151 of the PC 15 displays a heat map as shown in FIG. 24 on the display device 155 of the PC 15, and the process ends. The CPU 141 of the PC 15 stores a heat map or the like in the memory 152 of the PC 15 as needed.

FIG. 24 is a diagram showing an example of a heat map. In FIG. 24, the vertical axis shows the distance (m) in the Y direction in the XY coordinate system, and the horizontal axis shows the distance (m) in the X direction in the XY coordinate system. FIG. 24 shows an RSSI heat map showing the maximum value (dBm) of the RSSI level from all access points (APs) in halftone for each receiving module. In FIG. 24, the RSSI level is lower as the halftone is brighter and higher as the halftone is darker. In this example, the receiving modules include Wi-Fi modules Wi-Fi001 to Wi-Fi005, BLE (Bluetooth (registered trademark) Low Energy) modules BLE001 to BLE004, and BT (Bluetooth (registered trademark)) modules BT001 to BT003. Including.

According to the fourth embodiment, since the radio waves transmitted from the same source received by the plurality of receiving modules can be identified, the distance from each receiving module to the transmitting source is estimated from the time difference of radio wave reception in each receiving module. be able to. For this reason, it is possible to include the display of the estimation result of the position of the transmission source in the visualization of the radio wave environment such as drawing the heat map of the electric field strength distribution, and the heat map can be used to quickly investigate the radio wave environment and identify the cause of the problem. You can go to.

As described above, the radio wave identification device in the first to third embodiments can be applied to the radio wave environment visualization technique. Therefore, the radio wave identification device in the first to third embodiments is applied to the radio wave environment visualization technology to quickly investigate the cause when, for example, a wireless sensor network installed in a factory or the like malfunctions. It is suitable for cases and the like.

(Modification example)
In the modified example, in each of the above embodiments, the server 14 may execute at least a part of the processing of the PC 15, that is, a part or all of the processing of the PC 15. If the server 14 executes all the processing of the PC 15, the PC 15 can be omitted. Similarly, in each of the above embodiments, the PC 15 may execute at least a part of the processing of the server 14, that is, a part or all of the processing of the server 14. When the PC 15 executes all the processing of the server 14, the server 14 can be omitted. That is, in each of the above embodiments, the server 14 and the PC 15 may be replaced with a single computer that executes the processing of the server 14 and the PC 15.

The first to fourth serial numbers attached to each of the above embodiments do not represent the priority of the preferred embodiments. It is also clear that those skilled in the art can make numerous modifications and modifications.

The following additional notes will be further disclosed with respect to the embodiments including the above embodiments.
(Appendix 1)
Of the first received signal sequence received by the first receiving node and the second received signal sequence received by the second receiving node, the scale of the time axis of the second received signal sequence is scaled by the time expansion / contraction rate. While expanding and contracting, the correlation value with the first received signal sequence is calculated, and the second received signal sequence is offset by a time offset on the time axis to maximize the correlation value. The means of determining the time offset and
By applying the time expansion / contraction rate and the time offset at which the correlation value becomes the maximum value to the time information of the second received signal sequence, the first received signal sequence and the second received signal sequence are respectively. A means of associating packets having similar transmission start times, packet lengths, and signal strengths with each other on a one-to-one basis by comparing each packet of each packet.
When the correlation value that becomes the maximum value exceeds the threshold value, it is determined that the associated packet is a reception signal sequence of radio waves received by the first and second receiving nodes from the same transmission source. Judgment means to output the radio wave identification result and
A radio wave identification device characterized by being equipped with.
(Appendix 2)
The first data at a clipping timing such that the time information of the head data and the tail data of the second received signal sequence is always wider than the time information of the head data and the tail data of the first received signal series by a guard time or more. Further provided with an extraction means for clipping the received signal sequence and the second received signal sequence.
The radio wave identification device according to Appendix 1, wherein the determination means determines the time expansion / contraction rate and the time offset at which the correlation value becomes the maximum value from the received signal sequence extracted by the extraction means.
(Appendix 3)
The rule that the linking means shakes when the reception order of the packet of the linking candidate is different, or when duplicate linking occurs in a plurality of packets, and the order of the packets is not changed. Correct the error of packet linking by applying
The radio wave identification device according to Appendix 1 or 2, wherein the shaking corrects an error in packet association by shaking the packet of the association candidate by a certain range on the time axis and making fine adjustments. ..
(Appendix 4)
The radio wave identification result is associated with the reception strength of the first reception signal sequence and the second reception signal sequence with the ID information of the transmission source detected by the first reception node or the second reception node. The radio wave identification device according to any one of Supplementary note 1 to 3, further comprising an output means for outputting the ID association result.
(Appendix 5)
The determining means and the associating means process the first and second received signal sequences for the received signal sequences received by each receiving node pair among the received signal sequences received by the three or more receiving nodes. Repeat,
The radio wave identification device according to any one of Supplementary note 1 to 4, wherein the determination means merges the radio wave identification results for each receiving node pair.
(Appendix 6)
Of the first received signal sequence received by the first receiving node and the second received signal sequence received by the second receiving node, the scale of the time axis of the second received signal sequence is scaled by the time expansion / contraction rate. While expanding and contracting, the correlation value with the first received signal sequence is calculated, and the second received signal sequence is offset by a time offset on the time axis to maximize the correlation value. Determine the time offset,
By applying the time expansion / contraction rate and the time offset at which the correlation value becomes the maximum value to the time information of the second received signal sequence, the first received signal sequence and the second received signal sequence are respectively. Compare each packet that each packet has, and associate packets with similar transmission start time, packet length, and signal strength of each packet on a one-to-one basis.
When the correlation value that becomes the maximum value exceeds the threshold value, it is determined that the associated packet is a reception signal sequence of radio waves received by the first and second receiving nodes from the same transmission source. Output the radio wave identification result,
A radio wave identification method characterized in that a computer executes processing.
(Appendix 7)
The received signal sequence is set at a clipping timing such that the time information of the start data and the end data of the second received signal sequence is always wider than the time information of the start data and the end data of the first received signal sequence by a guard time or more. Extract,
The computer further executes the process,
The radio wave identification method according to Appendix 6, wherein the determination process determines the time expansion / contraction rate and the time offset at which the correlation value becomes the maximum value from the received signal sequence extracted by the extraction process.
(Appendix 8)
The rule that the linking process shakes when the receiving order of the packet of the linking candidate is different or when duplicate linking occurs in a plurality of packets, and the order of the packets is not changed. Correct the error of packet linking by applying
The radio wave identification method according to Appendix 6 or 7, wherein the shaking corrects an error in packet association by shaking the packet of the association candidate by a certain range on the time axis and making fine adjustments. ..
(Appendix 9)
The radio wave identification result is associated with the reception strength of the first reception signal sequence and the second reception signal sequence with the ID information of the transmission source detected by the first reception node or the second reception node. Outputs the ID link result
The radio wave identification method according to any one of Supplementary note 6 to 8, wherein the processing is further executed by the computer.
(Appendix 10)
The process of determining and the process of associating the first and second received signal sequences with respect to the received signal sequence received by each receiving node pair among the received signal sequences received by three or more receiving nodes. Repeat the process,
The radio wave identification method according to any one of Supplementary note 6 to 9, wherein the determination process merges the radio wave identification results for each receiving node pair.
(Appendix 11)
A first receiving node that outputs the first received signal sequence received, and
A second receiving node that is installed at a location different from the first receiving node, has an internal clock independent of the internal clock of the first receiving node, and outputs a second received signal sequence received. ,
A radio wave identification device that outputs a radio wave identification result based on the first received signal sequence and the second received signal sequence, and
Based on the radio wave identification result, a device for creating a heat map in which the received signal strength of the radio wave and the traffic level for each location of the first and second receiving nodes are expressed in color, and
With
The radio wave identification device is
The correlation value with the first received signal sequence is calculated while expanding and contracting the scale of the time axis of the second received signal sequence with the time expansion / contraction rate, and the second received signal sequence is offset only by the time on the time axis. A determination means for determining the time expansion / contraction rate and the time offset at which the correlation value is offset to the maximum value, and
By applying the time expansion / contraction rate and the time offset at which the correlation value becomes the maximum value to the time information of the second received signal sequence, the first received signal sequence and the second received signal sequence are respectively. A means of associating packets having similar transmission start times, packet lengths, and signal strengths with each other on a one-to-one basis by comparing each packet of each packet.
When the correlation value that becomes the maximum value exceeds the threshold value, it is determined that the associated packet is a reception signal sequence of radio waves received by the first and second receiving nodes from the same transmission source. Judgment means to output the radio wave identification result and
A radio wave environment visualization system characterized by having.
(Appendix 12)
The radio wave environment visualization system according to Appendix 11, wherein the device for creating the heat map has means for displaying the position information and ID information of the transmission source on the heat map.
(Appendix 13)
The radio wave environment visualization system according to Appendix 11 or 12, wherein the radio wave identification device and the device for creating the heat map are formed by a single computer.

Although the disclosed radio wave identification device, radio wave identification method and radio wave environment visualization system have been described above by way of examples, the present invention is not limited to the above examples, and various modifications and improvements can be made within the scope of the present invention. It goes without saying that it is possible.

11-1 to 11-3 Radio environment visualization system 12 Transmission station 13-1 to 13-n Reception module 14 Server 15 PC
151 CPU
152 Memory 153 I / F
154 Input device 155 Display device 156 Bus

Claims (5)

Of the first received signal sequence received by the first receiving node and the second received signal sequence received by the second receiving node, the scale of the time axis of the second received signal sequence is scaled by the time expansion / contraction rate. While expanding and contracting, the correlation value with the first received signal sequence is calculated, and the second received signal sequence is offset by a time offset on the time axis to maximize the correlation value. The means of determining the time offset and
By applying the time expansion / contraction rate and the time offset at which the correlation value becomes the maximum value to the time information of the second received signal sequence, the first received signal sequence and the second received signal sequence are respectively. A means of associating packets having similar transmission start times, packet lengths, and signal strengths with each other on a one-to-one basis by comparing each packet of each packet.
When the correlation value that becomes the maximum value exceeds the threshold value, it is determined that the associated packet is a reception signal sequence of radio waves received by the first and second receiving nodes from the same transmission source. Judgment means to output the radio wave identification result and
A radio wave identification device characterized by being equipped with. The first data at a clipping timing such that the time information of the head data and the tail data of the second received signal sequence is always wider than the time information of the head data and the tail data of the first received signal series by a guard time or more. Further provided with an extraction means for clipping the received signal sequence and the second received signal sequence.
The radio wave identification device according to claim 1, wherein the determination means determines the time expansion / contraction rate and the time offset at which the correlation value becomes the maximum value from the received signal sequence extracted by the extraction means. The rule that the linking means shakes when the reception order of the packets of the linking candidate is different, or when duplicate linking occurs in a plurality of packets, and the order of the packets is not changed. Correct the error of packet linking by applying
The radio wave identification according to claim 1 or 2, wherein the shaking corrects an error in packet association by shaking the packet of the association candidate by a certain range on the time axis and making fine adjustments. apparatus. Of the first received signal sequence received by the first receiving node and the second received signal sequence received by the second receiving node, the scale of the time axis of the second received signal sequence is scaled by the time expansion / contraction rate. While expanding and contracting, the correlation value with the first received signal sequence is calculated, and the second received signal sequence is offset by a time offset on the time axis to maximize the correlation value. Determine the time offset,
By applying the time expansion / contraction rate and the time offset at which the correlation value becomes the maximum value to the time information of the second received signal sequence, the first received signal sequence and the second received signal sequence are respectively. Compare each packet that each packet has, and associate packets with similar transmission start time, packet length, and signal strength of each packet on a one-to-one basis.
When the correlation value that becomes the maximum value exceeds the threshold value, it is determined that the associated packet is a reception signal sequence of radio waves received by the first and second receiving nodes from the same transmission source. Output the radio wave identification result,
A radio wave identification method characterized in that a computer executes processing. A first receiving node that outputs the first received signal sequence received, and
A second receiving node that is installed at a location different from the first receiving node, has an internal clock independent of the internal clock of the first receiving node, and outputs a second received signal sequence received. ,
A radio wave identification device that outputs a radio wave identification result based on the first received signal sequence and the second received signal sequence, and
Based on the radio wave identification result, a device for creating a heat map in which the received signal strength of the radio wave and the traffic level for each location of the first and second receiving nodes are expressed in color, and
With
The radio wave identification device is
The correlation value with the first received signal sequence is calculated while expanding and contracting the scale of the time axis of the second received signal sequence with the time expansion / contraction rate, and the second received signal sequence is offset only by the time on the time axis. A determination means for determining the time expansion / contraction rate and the time offset at which the correlation value is offset to the maximum value, and
By applying the time expansion / contraction rate and the time offset at which the correlation value becomes the maximum value to the time information of the second received signal sequence, the first received signal sequence and the second received signal sequence are respectively. A means of associating packets having similar transmission start times, packet lengths, and signal strengths with each other on a one-to-one basis by comparing each packet of each packet.
When the correlation value that becomes the maximum value exceeds the threshold value, it is determined that the associated packet is a reception signal sequence of radio waves received by the first and second receiving nodes from the same transmission source. Judgment means to output the radio wave identification result and
A radio wave environment visualization system characterized by having.