JP5099102B2 - Radio identification device and radio identification method - Google Patents

Description

  The present invention relates to a radio identification device and a radio identification method, and more particularly to a radio identification device and a radio identification method for efficiently monitoring radio waves.

  To identify an illegal radio device, it is necessary to go to the site of the radio device that is outputting illegal radio waves, and to check whether or not illegal radio waves are being output on the spot. And For this reason, a radio identification device has been proposed as a method for efficiently monitoring radio waves.

  For example, Patent Document 1 describes a wireless device identification device using FM detection. In this wireless device identification apparatus, frequency fluctuations that are seen during a wireless device's press talk are converted into FM detection signals by the FM detection method, and the rise of this FM detection signal is used as a feature vector of the wireless device. An unknown radio model or individual is identified from the similarity to the feature vector.

  Further, Patent Document 2 discloses a radio identification device having a configuration in which a spectrogram pattern unique to a radio is retained even for a received signal including noise, using a physical characteristic that frequency information is hardly affected by noise. Is disclosed.

  Further, Patent Document 3 discloses a distance measuring device that uses a threshold value to distinguish a radar target reflected wave and noise, and obtains the distance to the target by measuring the frequency (beat frequency) of the signal exceeding the threshold value. It is disclosed. In Patent Document 3, measuring beat frequency is called identification.

JP 2006-211250 A JP 2004-214817 A Japanese Patent Laid-Open No. 09-090024

  However, in the wireless device identification device described in Patent Document 1, if a reception filter is provided immediately before the feature vector waveform extraction in order to prevent interference due to adjacent channels and improve the reception S / N, the frequency variation reduces the bandwidth of the reception filter. In the section exceeding, the received signal is removed at the output of the reception filter. In this case, the feature vector cannot be accurately extracted, and even if the matching degree of the feature vector in the in-band section is high, the matching degree in the entire section is lowered, and as a result, the performance of radio identification is deteriorated. There's a problem.

  If the reception filter is not provided, the feature vector waveform cannot be collected accurately due to interference by adjacent channels, and the influence of noise increases as the reception S / N deteriorates. There is a problem that performance deteriorates.

  In addition, the wireless device identification apparatus described in Patent Document 2 is based on a decrease in the received signal level due to fading, or because the frequency deviation of the received signal is larger than the filter band for adjacent channel suppression. Inferior received signals in which the signal is buried in the noise level (negative S / N value) cannot hold the unique pattern, making radio identification difficult.

  Further, even when the wireless device identification apparatus described in Patent Document 2 is combined with the invention for invalidating noise by setting the threshold described in Patent Document 3, the signal detected by the reception filter is also used. Since only noise is present, it is not possible to construct the present invention using a threshold value to remove the noise.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a wireless device identification apparatus and a wireless device identification method that can reduce the influence of feature vector waveforms on noise and improve the performance of wireless device identification. .

  In order to achieve the above object, a radio identification apparatus according to the present invention includes a digital complex envelope signal generating means for generating a digital complex envelope signal from a reception signal obtained by receiving a transmission signal of a radio, and a digital complex envelope signal. An extraction means for extracting a feature vector waveform which is a frequency fluctuation waveform at the time of rising, a determination means for determining whether or not the received signal energy of the digital complex envelope signal is equal to or less than a threshold, and a determination And an identification processing means for forming a feature vector waveform of a section determined as a section below a threshold by the means into a specific waveform and performing a radio identification process using a feature vector waveform of a section where the received signal energy is larger than the threshold. It is characterized by.

  In order to achieve the above object, a radio identification method of the present invention includes a digital complex envelope signal generation step for generating a digital complex envelope signal from a reception signal obtained by receiving a transmission signal of a radio, a digital complex envelope An extraction step of FM-detecting the envelope signal to extract a feature vector waveform which is a frequency fluctuation waveform at the time of rising; and a determination step of determining whether or not the received signal energy of the digital complex envelope signal is within a threshold value or less An identification processing step of forming a feature vector waveform of a section determined as a section equal to or less than a threshold by the determination step into a specific waveform, and performing a radio identification process using a feature vector waveform of a section in which the received signal energy is larger than the threshold; It is characterized by including.

  ADVANTAGE OF THE INVENTION According to this invention, the performance of radio | wireless machine identification can be improved by setting the low energy received signal input period below a preset threshold value to an invalid period or an interpolation period, and reducing the influence by noise.

It is a block diagram of 1st Embodiment of the radio | wireless machine identification apparatus of this invention. It is a block diagram of one Embodiment of the invalid area determination circuit in FIG. It is a block diagram of one Embodiment of the FM detection feature vector extraction part in FIG. It is a figure which shows an example of the feature vector waveform by which the digital complex envelope signal out of the specific band was interrupted | blocked by the receiving filter. It is a figure which shows an example of the feature vector waveform by which the value of the feature vector was set to zero only in the area below a certain threshold value of the energy of the digital complex envelope signal calculated by the received energy measuring circuit in FIG. It is a flowchart for operation | movement description of 1st Embodiment of the radio | wireless machine identification device of this invention. It is a block diagram of 2nd Embodiment of the radio | wireless machine identification device of this invention. It is a block diagram of one Embodiment of the FM detection feature vector extraction part in FIG. It is a figure which shows an example of the feature vector waveform using the linear interpolation which represents the feature vector exceeding a specific zone | line with a straight line. It is a flowchart for operation | movement description of 2nd Embodiment of the radio | wireless machine identification device of this invention.

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

(First embodiment)
FIG. 1 shows a block diagram of a first embodiment of a radio identification device according to the present invention. As shown in the figure, the radio identification apparatus 1A of the present embodiment is supplied with a reception signal from the receiver 3, and receives an A / D converter 4, a reception filter 5, an invalid interval determination circuit 6, an FM detection feature vector. An extraction unit 7A, a feature vector DB (database) 8 and a radio device identification processing unit 9 are included.

  The A / D converter 4 receives, as an input signal, an analog intermediate frequency signal obtained by converting a signal from a radio (not shown) received by the antenna 2 into an intermediate frequency by the receiver 3. Convert the intermediate frequency signal into a digital complex envelope signal. The reception filter 5 is a band filter that blocks a digital complex envelope signal outside a specific pass frequency band.

  The invalid interval determination circuit 6 receives a digital complex envelope signal frequency-selected by the reception filter 5 as an input signal, and invalidates a feature vector whose received signal energy calculated from the input digital complex envelope signal is a certain threshold value or less. Determine.

  The FM detection feature vector extraction unit 7A extracts a frequency fluctuation waveform at the time of rising, that is, a feature vector waveform, by performing FM detection on the digital complex envelope signal. The wireless device identification processing unit 9 refers to the feature vector waveform transferred from the FM detection feature vector extraction unit 7A and the feature vector waveform stored in advance in the feature vector DB 8 according to an instruction from the user, The radio is identified from the correlation based on the peak value. If there is no correlation, the radio equipment identification processing unit 9 transfers and registers the feature vector waveform in the feature vector DB 8 based on the user's instruction.

  Next, a detailed configuration of the invalid section determination circuit 6 in FIG. 1 will be described. FIG. 2 shows a block diagram of an embodiment of the invalid section determination circuit 6. As shown in the figure, the invalid interval determination circuit 6 includes a reception energy measurement circuit 61 and a threshold determination circuit 62.

  The reception energy measurement circuit 61 calculates and measures the reception signal energy E (n) from the in-phase component I (n) and the quadrature component Q (n) of the digital complex envelope signal that has passed through the reception filter 5 by the following equation.

E (n) = {I (n)} ² + {Q (n)} ²
The threshold determination circuit 62 determines that the received signal energy E (n) measured by the received energy measurement circuit 61 is invalid if it is equal to or lower than a preset threshold, and outputs the determination result to the FM detection feature vector extraction unit 7A. To do.

  FIG. 3 shows a block diagram of an embodiment of the FM detection feature vector extraction unit 7A in FIG. As shown in FIG. 3, the FM detection feature vector extraction unit 7 </ b> A includes an FM detection circuit 71 and a feature vector zero padding circuit 72.

  The FM detection circuit 71 performs FM detection of the digital complex envelope signal that has passed through the reception filter 5, and extracts and outputs the frequency fluctuation waveform at the rising edge of the signal as a feature vector waveform. The feature vector zero padding circuit 72 transfers the feature vector waveform from the FM detection circuit 71 as it is when the determination signal from the invalid interval determination circuit 6 indicates that it is an effective interval, and the determination signal is an invalid interval. In this case, instead of the feature vector waveform from the FM detection circuit 71, a feature vector of the invalid section and value 0 is output.

  As described above, according to the present embodiment, the invalid section determination circuit 6 and the FM detection feature vector extraction unit 7A perform invalidity in which the received signal energy E (n) of the feature vector waveform is equal to or less than a preset threshold value. By excluding the section from the identification processing range, the influence of noise is reduced and the performance of radio identification is improved.

  FIG. 4 is an example of a feature vector waveform in which a digital complex envelope signal outside a specific band is blocked by the reception filter 5. In a section where the frequency fluctuation reaches the outside of the band of the reception filter 5, the input signal to the FM detection feature vector extraction unit 7A is only a noise signal within the band of the reception filter 5, so that a noise feature vector waveform is extracted. .

  In FIG. 4, periods T1, T3, and T5 are valid periods, and periods T2 and T4 are invalid periods. In the invalid periods T2 and T4, as described above, the received signal energy E (n) is a low energy received signal input period equal to or less than a preset threshold value, and only the noise signal within the band of the reception filter 5 is obtained. The low energy received signal is a signal in which the signal component of the received signal is smaller than the noise component, and the received signal energy is comparable to the noise energy.

  FIG. 5 shows the value of the feature vector only in an invalid interval where the received signal energy E (n) is equal to or less than a preset threshold value by the threshold determination circuit 62 using the energy of the digital complex envelope signal calculated by the received energy measuring circuit 61. An example of an output waveform of the FM detection feature vector extraction unit 7A in which is set to 0 is shown.

  In FIG. 5, the waveforms of the periods Ta, Tc, Te show the feature vector waveforms in the valid periods T1, T3, T5 of FIG. 4, and the waveforms of the periods Tb, Td are the features of the value 0 in the invalid periods T2, T4 of FIG. A vector waveform is shown.

  Next, the operation of the wireless device identification apparatus 1A of FIG. 1 will be described with reference to the flowchart of FIG. The receiver 3 converts a signal from a radio (not shown) received by the antenna 2 into an intermediate frequency signal of an intermediate frequency that is an analog signal. The A / D converter 4 converts this intermediate frequency signal into a digital complex envelope signal (step S1).

  The reception filter 5 performs band limitation to block a digital complex envelope signal outside a specific pass frequency band from the digital complex envelope signal output from the A / D converter 4 (step S2). The invalid interval determination circuit 6 receives a digital complex envelope signal of a specific pass frequency band that has passed through the reception filter 5 as an input signal, and whether or not the received signal energy calculated from the input digital complex envelope signal is equal to or less than a threshold value. To select whether the feature vector is invalid or valid (step S3).

  In other words, as described above, the invalid interval determination circuit 6 receives the low energy received with the received signal energy calculated from the input digital complex envelope signal from the reception filter 5 being equal to or less than the threshold as in the periods T2 and T4 shown in FIG. Invalid is selected during the signal input period, and an instruction for setting the value of the feature vector to 0 is output to the FM detection feature vector extraction unit 7A (step S4). Further, the invalid interval determination circuit 6 selects valid in the input period in which the received signal energy calculated from the input digital complex envelope signal is larger than the threshold, as in the periods T1, T3, and T5 shown in FIG. A command for receiving the value of the feature vector from the reception filter 5 is output to the detection feature vector extraction unit 7A (step S5).

  The FM detection feature vector extraction unit 7A performs FM detection of the digital complex envelope signal that has passed through the reception filter 5 by the FM detection circuit 71 shown in FIG. 3, and presets the frequency fluctuation waveform of the signal rise as a feature vector waveform. Up to the section is extracted (Y in step S6, S7). At this time, if the feature vector zero padding circuit 72 shown in FIG. 3 indicates that the determination signal from the invalid section determination circuit 6 is a valid section, the FM detection feature vector extraction unit 7A has an FM detection circuit 71. When the determination signal indicates that it is an invalid section, the feature vector waveform from the FM detector circuit 71 is output instead of the feature vector waveform from the FM detection circuit 71. . Thereby, a feature vector waveform in which the value of the feature vector is set to 0 only for the invalid section as shown in FIG. 5 is output from the FM detection feature vector extraction unit 7A.

  Subsequently, the radio identification processing unit 9 acquires the feature vector waveform from the FM detection feature vector extraction unit 7A, and registers the feature vector waveform as a new feature vector waveform in the feature vector DB 8 or is stored in advance. It is selected whether to identify which model or individual of the plurality of known wireless devices (step S8).

  In the case of registering the feature vector waveform of the wireless device, the feature vector waveform is transferred from the wireless device identification processing unit 9 to the feature vector DB 8 in accordance with a user instruction, and the feature vector waveform is stored in the feature vector DB 8 (step S9). . When a feature vector of a radio that does not exist in the feature vector DB 8 is acquired, registration is selected based on a user instruction.

  On the other hand, in the case of identification of a radio device, the radio device identification processing unit 9 according to a user instruction stores a feature vector waveform transferred from the FM detection feature vector extraction unit 7A and a stored feature transferred from the feature vector DB 8. The wireless device is identified from the evaluation based on the similarity to the vector (step S10). In order to obtain the similarity, there are methods such as correlation of peak values and distance between signals.

  As described above, according to the present embodiment, the low energy received signal input period equal to or less than the preset threshold value that is only the noise signal in the band of the reception filter 5 is set as the invalid period, and the value of the feature vector is set to 0. Thus, since it is not used for the identification process, the influence of noise can be reduced and the performance of radio identification can be improved. In addition, according to the present embodiment, even if the reception filter 5 is used to prevent interference due to adjacent channels, identification processing can be performed using only feature vectors other than the invalid section, so that the performance of radio identification is degraded. Can be prevented.

  Moreover, in this embodiment, it can be set as the economically excellent structure. The reason is that only the reception filter 5 and the invalid interval determination circuit 6 are added to the existing radio identification device, and the design can be made with generally used inexpensive hardware.

  Furthermore, in this embodiment, the feature that it is excellent in real-time property is acquired. The reason is that in this embodiment, the time for changing the feature vector is short, and the amount of calculation required for processing is almost the same as that of the existing identification circuit.

(Second Embodiment)
FIG. 7 shows a block diagram of a second embodiment of the radio identification device according to the present invention. As shown in the figure, the radio identification device 1B of the present embodiment is supplied with a reception signal from the receiver 3, and receives an A / D converter 4, a reception filter 5, an interpolation interval determination circuit 14, an FM detection feature vector. An extraction unit 7B, a feature vector DB (database) 8 and a radio device identification processing unit 9 are included. In FIG. 7, the same components as those in FIG.

  In FIG. 7, the interpolation interval determination circuit 14 determines that the input interval of the digital complex envelope signal outside the specific band blocked by the reception filter 5 is an interpolation interval, and outputs the determination result to the FM detection feature vector extraction unit 7B. To do. The interpolation determination circuit 14 has a circuit configuration similar to that of the invalid section determination circuit 6.

  FIG. 8 shows a block diagram of an embodiment of the FM detection feature vector extraction unit 7B. As shown in the figure, the FM detection feature vector extraction unit 7B includes an FM detection circuit 71 and a feature vector interpolation circuit 73.

  The FM detection circuit 71 performs FM detection of the digital complex envelope signal that has passed through the reception filter 5, and extracts and outputs the frequency fluctuation waveform at the rising edge of the signal as a feature vector waveform. The feature vector interpolation circuit 73 forms a new feature vector waveform by performing interpolation processing (for example, linear interpolation, Lagrange interpolation) on the feature vectors in the interpolation section. FIG. 9 shows an example of a feature vector waveform using linear interpolation that represents a feature vector exceeding a specific band by a straight line.

  Next, the operation of the present embodiment will be described with reference to the flowchart of FIG. In the figure, the same processing steps as those in FIG. 6 are denoted by the same reference numerals, and the description thereof is omitted.

  In step S11 shown in FIG. 10, the interpolation interval determination circuit 14 receives a digital complex envelope signal of a specific pass frequency band that has passed through the reception filter 5 as an input signal, and the input interval of the input digital complex envelope signal is the interpolation interval. Or whether it is a valid section. That is, in step S11, the interpolation interval determination circuit 14 determines that the input interval of the digital complex envelope signal is an interpolation interval when the digital complex envelope signal outside the specific band blocked by the reception filter 5 is input. When it is determined that the input section is an input section that is not blocked by the reception filter 5, the input section is determined to be an effective section.

  The FM detection feature vector extraction unit 7B performs FM detection of the digital complex envelope signal that has passed through the reception filter 5 by the FM detection circuit 71 shown in FIG. 8 and presets the frequency fluctuation waveform of the signal rise as a feature vector waveform. Up to the section is extracted (Y in step S6, S7).

  At this time, when the feature vector interpolation circuit 73 shown in FIG. 8 indicates that the determination signal from the interpolation section determination circuit 14 is an effective section, the FM detection feature vector extraction unit 7B starts from the FM detection circuit 71. When the feature vector waveform is transferred as it is and the determination signal indicates that it is an interpolation section, interpolation processing (for example, linear interpolation, Lagrangian interpolation) is performed on the feature vector from the FM detection circuit 71. Thus, a new feature vector waveform is formed.

  When linear interpolation represented by a straight line is adopted as the above-described interpolation processing, a new feature vector waveform in which the value of the feature vector is interpolated by a straight line for the interpolation section as shown in FIG. Is output.

  As described above, according to the present embodiment, the influence of the noise is reduced by performing the interpolation process on the feature vector of the interpolation section including only noise, and the feature vector can be arbitrarily changed by the interpolation process. The error rate of machine identification can be reduced. That is, according to the present embodiment, it is expected that the optimum feature vector waveform in radio identification is investigated and the performance of radio identification is improved. In addition, the present embodiment, like the above-described embodiment, has an advantage that it can be configured economically and has excellent real-time properties.

  The present invention is not limited to the above embodiment. For example, in feature vector extraction, a spectrogram can be obtained from a received signal, and a peak value can be obtained to obtain a feature vector waveform. In this case, a known circuit for extracting the spectrogram peak value may be used instead of the FM detection feature vector extraction units 7A and 7B.

1A, 1B Radio equipment identification device 2 Antenna 3 Receiver 4 A / D converter 5 Reception filter 6 Invalid section judgment circuit 7A, 7B FM detection feature vector extraction unit 8 Feature vector DB
9 Radio identification processing unit 14 Interpolation section determination circuit 61 Received energy measurement circuit 62 Threshold determination circuit 71 FM detection circuit 72 Feature vector zero padding circuit 73 Feature vector interpolation circuit

Claims (12)

A digital complex envelope signal generating means for generating a digital complex envelope signal from a received signal obtained by receiving a transmission signal of a radio;
Extraction means for performing FM detection on the digital complex envelope signal and extracting a feature vector waveform which is a frequency fluctuation waveform at the time of rising;
Determining means for determining whether or not the received signal energy of the digital complex envelope signal is a section below a threshold;
The feature vector waveform of the section determined as the section equal to or less than the threshold by the determining means is formed into a specific waveform, and radio equipment identification processing is performed using the feature vector waveform of the section where the received signal energy is larger than the threshold. An identification processing means for performing wireless identification. A digital complex envelope signal generating means for generating a digital complex envelope signal from a received signal obtained by receiving a transmission signal of a radio;
Extraction means for performing FM detection on the digital complex envelope signal and extracting a feature vector waveform which is a frequency fluctuation waveform at the time of rising;
A determination unit that determines a section where the received signal energy of the digital complex envelope signal is equal to or less than a threshold value as an invalid section, and determines a section where the received signal energy is greater than the threshold value as a valid section;
An identification process in which the feature vector waveform of the section corresponding to the invalid section is set to a predetermined value and excluded from the identification processing range, and a radio identification process is performed using the feature vector waveform of the section corresponding to the valid section And a radio identification device. A digital complex envelope signal generating means for generating a digital complex envelope signal from a received signal obtained by receiving a transmission signal of a radio;
Extraction means for performing FM detection on the digital complex envelope signal and extracting a feature vector waveform which is a frequency fluctuation waveform at the time of rising;
A determination unit that determines an interval in which the received signal energy of the digital complex envelope signal is equal to or less than a threshold as an interpolation interval, and determines an interval in which the received signal energy is greater than the threshold as an effective interval;
Radio equipment identification using the feature vector waveform after the interpolation process obtained by performing the interpolation process on the feature vector waveform in the section corresponding to the interpolation section and the feature vector waveform in the section corresponding to the effective section An identification processing means for performing processing.   Reception filter means for excluding signal components outside a specific frequency band from the extraction means and supplying the digital complex envelope signal after the exclusion to the determination means and the identification processing means. The wireless device identification device according to any one of claims 1 to 3, further comprising: The identification processing means includes
A feature vector zero padding means for setting the value of the feature vector waveform in the section corresponding to the invalid section to zero and outputting it together with the feature vector waveform in the section corresponding to the valid section;
Processing means for performing radio equipment identification processing based on a correlation between the feature vector waveform output from the feature vector zero padding means and a feature vector waveform stored in advance in a database. The radio | wireless machine identification device of Claim 2. The identification processing means includes
Interpolating the feature vector waveform in the section corresponding to the interpolation section, and outputting the feature vector waveform together with the feature vector waveform in the section corresponding to the effective section;
And a processing unit for performing a radio identification process based on a correlation between the feature vector waveform output from the feature vector interpolation unit and a feature vector waveform stored in advance in a database. Item 4. The wireless device identification apparatus according to Item 3. A digital complex envelope signal generating step for generating a digital complex envelope signal from a received signal obtained by receiving a transmission signal of a radio;
An extraction step of performing FM detection on the digital complex envelope signal and extracting a feature vector waveform which is a frequency fluctuation waveform at the time of rising;
A determination step of determining whether or not the received signal energy of the digital complex envelope signal is a section below a threshold;
The feature vector waveform of the section determined as the section equal to or less than the threshold by the determination step is formed into a specific waveform, and radio equipment identification processing is performed using the feature vector waveform of the section where the received signal energy is larger than the threshold. A radio identification method comprising: an identification processing step to be performed. A digital complex envelope signal generating step for generating a digital complex envelope signal from a received signal obtained by receiving a transmission signal of a radio;
An extraction step of performing FM detection on the digital complex envelope signal and extracting a feature vector waveform which is a frequency fluctuation waveform at the time of rising;
A step of determining an interval where the received signal energy of the digital complex envelope signal is equal to or less than a threshold as an invalid interval, and determining an interval where the received signal energy is greater than the threshold as an effective interval;
An identification process in which the feature vector waveform of the section corresponding to the invalid section is set to a predetermined value and excluded from the identification processing range, and a radio identification process is performed using the feature vector waveform of the section corresponding to the valid section A radio identification method comprising the steps of: A digital complex envelope signal generating step for generating a digital complex envelope signal from a received signal obtained by receiving a transmission signal of a radio;
An extraction step of performing FM detection on the digital complex envelope signal and extracting a feature vector waveform which is a frequency fluctuation waveform at the time of rising;
A determination step of determining a section where the received signal energy of the digital complex envelope signal is equal to or less than a threshold as an interpolation section, and determining a section where the received signal energy is larger than the threshold as an effective section;
Radio equipment identification using the feature vector waveform after the interpolation process obtained by performing the interpolation process on the feature vector waveform in the section corresponding to the interpolation section and the feature vector waveform in the section corresponding to the effective section An identification processing step for performing processing.   A frequency selection that excludes signal components outside a specific frequency band from the digital complex envelope signal extracted by the extraction step, and causes the digital complex envelope signal after the exclusion to be processed in the determination step and the identification processing step. The wireless device identification method according to claim 7, further comprising a step. The identification processing step includes
Setting the value of the feature vector waveform in the section corresponding to the invalid section to zero, and outputting the feature vector waveform together with the feature vector waveform in the section corresponding to the valid section; and
And a processing step of performing radio equipment identification processing based on a correlation between the feature vector waveform obtained in the feature vector zero padding step and a feature vector waveform stored in advance in a database. The radio | wireless machine identification method of Claim 8. The identification processing step includes
Interpolating the feature vector waveform in the section corresponding to the interpolation section, and outputting the feature vector waveform together with the feature vector waveform in the section corresponding to the effective section; and
And a processing step of performing a radio identification process based on a correlation between the feature vector waveform obtained in the feature vector interpolation step and a feature vector waveform stored in advance in a database. Item 10. The wireless device identification method according to Item 9.

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