JP6070252B2 - Signal detection apparatus, signal detection method, and reception apparatus - Google Patents

Description

  The present invention relates to a signal detection device, a signal detection method, and a reception device, and more particularly to a signal detection device, a signal detection method, and a reception device that detect a signal to be extracted from a received signal.

  Radio wave monitoring devices (radio wave monitoring receivers) that monitor radio waves are known for the purpose of controlling illegal radio waves and measuring the use of radio waves. The radio wave monitoring device detects communication signals used by various wireless communication devices for wireless communication from broadband received signals, and monitors whether they are used for communication purposes as requested.

  For example, Patent Documents 1 and 2 are known as techniques related to signal detection. Patent Document 1 describes managing a radio frequency band based on a spectrum of the radio frequency band. Patent Document 2 describes that a broadband signal is detected from the frequency spectrum of an acoustic signal.

JP 2005-523616 A JP 2004-118108 A

  In a related radio wave monitoring apparatus (signal detection apparatus), the detection of a communication signal is generally determined as “detection” (threshold determination) when the power of the received signal exceeds a preset threshold value.

  However, in real space, in addition to communication signals, noise and leaked radio waves generated from other than the communication device are also scattered, and if only threshold determination is performed, these unnecessary signals are often detected as demodulation targets. For this reason, there exists the present condition which becomes the obstruction of a radio wave monitoring business. If the reception sensitivity is lowered, the possibility of picking up unnecessary signals is reduced. However, since necessary signals are missed, it is not an effective method.

  As described above, the related technique has a problem that it is difficult to suppress detection of unnecessary signals without reducing reception sensitivity.

  An object of the present invention is to provide a signal detection device, a signal detection method, and a reception device that can solve such problems.

  The signal detection apparatus according to the present invention includes a bandwidth / duration measurement unit that measures the bandwidth and duration of a received signal that is a wideband signal, and a bandwidth time product that is a product of the measured bandwidth and duration. An extraction signal detection unit that detects an extraction signal based on the signal, a broadband signal delay unit that delays the reception signal as a broadband signal, and a signal extraction unit that extracts the detected extraction signal from the delayed reception signal It is.

  The signal detection method according to the present invention measures a bandwidth and duration of a received signal that is a wideband signal, detects an extraction signal based on a bandwidth time product that is a product of the measured bandwidth and duration, and The received signal is delayed as a wideband signal, and the detected extracted signal is extracted from the delayed received signal.

  A receiving apparatus according to the present invention is based on a bandwidth / duration measuring unit that measures a bandwidth and duration of a received signal that is a wideband signal, and a bandwidth time product that is a product of the measured bandwidth and duration. An extracted signal detecting unit for detecting an extracted signal; a wideband signal delaying unit for delaying the received signal as a wideband signal; a signal extracting unit for extracting the detected extracted signal from the delayed received signal; and the extracted extraction And a demodulator that demodulates the extracted signal in accordance with the signal modulation method.

  According to the present invention, it is possible to provide a signal detection apparatus, a signal detection method, and a reception apparatus that can suppress detection of unnecessary signals without reducing reception sensitivity.

It is a block diagram for demonstrating the characteristic of the signal detection apparatus which concerns on embodiment. 1 is a configuration diagram illustrating a configuration of a radio wave monitoring device according to a first embodiment. 4 is a spectrum and spectrogram for explaining the operation of the radio wave monitoring apparatus according to the first embodiment. 2 is a spectrum for explaining the operation of the radio wave monitoring apparatus according to the first embodiment.

(Features of the embodiment)
Prior to the description of the embodiment, an outline of features of the embodiment will be described. FIG. 1 shows a main configuration of the signal detection apparatus according to the embodiment. As shown in FIG. 1, the signal detection device 10 (corresponding to a radio wave monitoring device 100 described later) includes a bandwidth / duration measurement unit 11, an extraction signal detection unit 12, a wideband signal delay unit 14, and a signal extraction unit 13. I have. The bandwidth / duration measuring unit 11 measures the bandwidth and duration of a received signal that is a wideband signal. The extraction signal detection unit 12 (corresponding to a B · τ product determination unit 105 described later) detects the extraction signal based on the bandwidth time product which is the product of the measured bandwidth and duration. The broadband signal delay unit 14 (corresponding to a broadband FIFO memory 106 described later) delays the received signal as the broadband signal. The signal extraction unit 13 (corresponding to a DDC unit 107 described later) extracts an extracted signal detected from the delayed received signal.

  Thus, in the embodiment, the extraction signal (communication signal) is detected based on the bandwidth time product (B · τ product) of the received signal. As a result, detection of unnecessary signals can be suppressed to a low level without reducing reception sensitivity. In other words, for the purpose of extracting only the communication signal from the received signal, in the case of the communication signal, it is common that the received signal has a certain bandwidth and continues. is there. In the embodiment, it is used to measure the bandwidth and signal duration of the detected received signal, demodulate (for example, extract a signal) a signal whose product is equal to or greater than a set value, and set the set value. By not demodulating less than those, it is possible to reduce detection / demodulation processing of unnecessary received signals such as noise.

(Embodiment 1)
Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 2 shows a configuration of the radio wave monitoring apparatus 100 according to the present embodiment. The radio wave monitoring apparatus 100 is a receiving apparatus (signal detection apparatus) that receives radio waves, detects (extracts) communication signals from received signals, and demodulates them in order to monitor radio waves.

  As shown in FIG. 2, the radio wave monitoring apparatus 100 according to the present embodiment includes an AD converter 101, an FFT (Fast Fourier Transform) unit 102, a threshold determination unit 103, a bandwidth / duration measurement unit 104, B · τ. A product determination unit 105, a wide-band FIFO (First In First Out) memory 106, a DDC (Digital Down Converter) unit 107, a demodulation unit 108, and a reception antenna 109 are provided.

  The AD converter 101 samples an input analog signal, performs AD conversion to a digital signal, and further converts the digital signal into IQ data (IQ component). Specifically, the AD converter 101 receives a wideband received signal received by the receiving antenna 109, converts the received signal received from the AD, converts the received signal into wideband IQ data, and outputs the generated wideband IQ data. .

  The FFT unit 102 performs an FFT (Fast Fourier Transform) process on the input signal, and generates a frequency spectrum that can analyze the power distribution for each frequency band of the signal. Note that the FFT calculation itself may be performed using a general algorithm. Specifically, the FFT unit 102 receives the broadband IQ data output from the AD converter 101, performs FFT processing on the input broadband IQ data, generates spectrum data, and generates the generated spectrum data. Output.

  The threshold determination unit 103 compares the power (signal level) of the input signal with a preset threshold value (power threshold value), and outputs a signal whose power is greater than the threshold value. Specifically, the threshold determination unit 103 receives the spectrum data generated by the FFT unit 102, and performs threshold value detection on the input spectrum data based on a set threshold value. The threshold determination unit 103 outputs, as detection candidates (detection candidate signals), the center frequency and approximate bandwidth of the signal whose power exceeds the threshold value. As a result, noise with low power is removed and unnecessary detection processing is reduced.

  The bandwidth / duration measurement unit 104 measures the bandwidth B of the input signal and the duration τ during which the input signal continues (continues). Specifically, the bandwidth / duration measurement unit 104 inputs the detection candidate signal generated by the threshold determination unit 103 for a certain period of time, measures the bandwidth B of the input detection candidate signal, and detects it. The duration τ during which the candidate signal continues is measured, and the measured bandwidth B and duration τ are output. For example, the bandwidth / duration measurement unit 104 measures the bandwidth B of the signal at a predetermined bandwidth measurement time interval Δτ, and outputs the number n of bandwidth measurements that the signal has continued.

  The B · τ product determination unit 105 compares the bandwidth B of the input signal with the B · τ product of the duration τ and a preset set value, and outputs a signal having a B · τ product larger than the set value. . Specifically, the B · τ product determination unit 105 receives the bandwidth B and the duration τ measured by the bandwidth / duration measurement unit 104, and inputs the input bandwidth B and B of the duration τ. The τ product is calculated, and the center frequency and bandwidth of the signal with the calculated B · τ product equal to or greater than the set value are output as a detection signal (extracted signal). As a result, signals other than those to be monitored are removed, and unnecessary demodulation (extraction) processing is reduced. In addition to the determination of the B · τ product, the B · τ product determination unit 105 further determines that the bandwidth B is greater than or equal to the threshold and that the duration τ is greater than or equal to the threshold. It is good also as judgment conditions. As a result, the signal can be further narrowed down and unnecessary signals can be removed.

Δτ：帯域幅測定時間間隔
ｎ：受信信号が継続している間の帯域幅測定回数
Ｂｉ：受信信号の帯域幅 For example, the B · τ product determination unit 105 calculates the B · τ product according to the following Equation 1. That is, as shown in Equation 1, the bandwidth B of the received signal is multiplied by the bandwidth measurement time interval Δτ, and the multiplication result is integrated by the number of times of bandwidth measurement n while the received signal is continued to be B • Find the τ product.

Δτ: bandwidth measurement time interval n: number of times of bandwidth measurement while reception signal continues Bi: bandwidth of reception signal

  The wideband FIFO memory 106 is a reception buffer (reception signal storage unit) that temporarily stores a reception signal as a wideband signal without specifying a detection signal. Specifically, the broadband FIFO memory 106 receives the broadband IQ data output from the AD converter 101, holds the broadband IQ data in the input order, and outputs the stored broadband IQ data. The broadband FIFO memory 106 outputs the broadband IQ data after delaying it for a predetermined time. The delay of the broadband IQ data may be realized by the DDC unit 107 reading a signal that is earlier than the current delay time. For example, the wideband FIFO memory 106 includes a time period from when the AD converter 101 generates wideband IQ data (after receiving a reception signal) until the B · τ product determination unit 105 detects the detection signal, Delay data. That is, the signal is delayed by the processing time of the FFT unit 102, the processing time of the threshold determination unit 103, the processing time of the bandwidth / duration measurement unit 104, and the processing time of the B · τ product determination unit 105. For example, the time until the B · τ product determination unit 105 detects the detection signal may be measured, and the delay time may be dynamically controlled according to the measurement time.

  The DDC unit 107 performs DDC (Digital Down Converter) processing on the input signal to generate a demodurable signal. Specifically, the DDC unit 107 receives the wideband IQ data stored in the wideband FIFO memory 106 and the detection signal in which the B · τ product determination unit 105 determines that the B · τ product is equal to or greater than a set value. DDC processing is performed based on the center frequency and bandwidth output from the B · τ product determination unit 105 in the data, the signal (narrowband IQ data) is extracted, and the extracted IQ data is output.

  The demodulation unit 108 performs demodulation corresponding to the modulation method of the input signal. Specifically, the demodulator 108 receives the IQ data extracted by the DDC unit 107 and demodulates it using a method according to the input IQ data. For example, the demodulator 108 has an FSK (Frequency Shift Keying) type demodulator and a PSK (Phase Shift Keying) type demodulator, demodulates the input signal by each demodulator, and demodulates it by one of the demodulator. Outputs demodulated data that succeeded. Alternatively, the modulation scheme may be estimated based on the spectrum of the input signal, and the demodulation may be performed by a demodulator corresponding to the estimated modulation scheme. For example, the modulation scheme may be estimated by storing in advance the center frequency, bandwidth, duration, B · τ product, etc. of the signal indicating the characteristics of the modulation scheme and comparing it with the received signal.

  Next, the operation of the radio wave monitoring apparatus 100 according to the present embodiment will be described. In the radio wave monitoring apparatus 100, each unit performs signal processing as described above in accordance with the arrows shown in FIG. That is, the receiving antenna 109 receives a wideband signal having a certain bandwidth or more, and the AD converter 101 performs AD conversion on the received signal to convert it into IQ data (broadband IQ data). The IQ data is stored in the wide-band FIFO memory 106 while performing threshold calculation processing.

  Further, the IQ data is subjected to FFT processing in the FFT unit 102 to generate spectrum data, and the threshold determination unit 103 performs threshold determination to detect a detection candidate signal at a certain level or higher. FIG. 3A shows an example of spectrum data generated by the FFT unit 102. The threshold determination unit 103 compares the power of each frequency in the spectrum data with a threshold value, and detects a signal larger than the threshold value. In FIG. 3A, since the threshold is exceeded in the frequency bands 201 to 204, the center frequency and the approximate bandwidth of the frequency bands (detection candidate signals) 201 to 204 are output.

  In the present embodiment, the bandwidth B and duration measurement unit 104 further measures the bandwidth B and duration τ for the detected detection candidate signal, and then the B / τ product determination unit 105 The product of bandwidth and duration is compared with a set value (threshold). FIG. 3B is an example of a spectrogram corresponding to the spectrum of FIG. 3A, and shows an image of the B · τ product of the signal calculated by the B · τ product determination unit 105. FIG. 4 shows an image of the bandwidth B for each Δτ of the signal calculated by the B · τ product determination unit 105. The B · τ product may be calculated by generating spectrogram image data as shown in FIG. 3B and analyzing the image data to obtain the area of the signal distribution.

  As shown in FIG. 3B, the bandwidth / duration measurement unit 104 measures the bandwidth B at every bandwidth measurement time interval Δτ, and counts the number n of bandwidth measurements that the signal continues. In FIG. 3B, the bandwidth / duration measurement unit 104 measures and outputs the bandwidth B and the bandwidth measurement count n for each of the detection candidate signals 201-204.

For example, as shown in FIG. 4, the bandwidth / duration measuring unit 104 measures the bandwidth B ₁ measured at Δτ, the bandwidth B ₂ measured at ₂ , · Δτ, and the bandwidth B ₂ , 3 · Δτ. The bandwidth B ₄ measured when the bandwidth B ₃ , 4 · Δτ is output, and the number of times the bandwidth B is measured (for example, 4) is output. Further, the B · τ product determination unit 105 obtains the B · τ product according to the above Equation 1. In the example of FIG. 4, B ₁ × Δτ, B ₂ × Δτ, B ₃ × Δτ, and B ₄ × Δτ are calculated and integrated. The bandwidth / duration measurement unit 104 calculates the B · τ product for each of the detection candidate signals 201 to 204 in FIG. 3B, and the center frequency of the signal (detection signal) where the B · τ product is larger than the set value. And output bandwidth. For example, when the B · τ product of the detection candidate signals 201 to 204 is larger than the set value, the center frequency and the bandwidth of the detection candidate signals 201 to 204 are output.

  Thereafter, the DDC unit 107 performs DDC processing on the detection signal of the broadband IQ data stored in the broadband FIFO memory 106. For example, when the signals 201 to 204 in FIG. 3B are detection signals, the signals 201 to 204 are extracted and output by DDC processing. The demodulator 108 performs demodulation processing on the extracted signal and outputs a final result.

  As described above, in the present embodiment, in the radio wave monitoring apparatus (signal detection apparatus), the signal bandwidth B and the signal duration τ are measured among the received signals detected from a certain broadband signal, and the B · τ product is measured. Only signals with a value greater than or equal to the set value are to be demodulated, and those with a B · τ product less than the set value are not demodulated. Thereby, detection of unnecessary signals can be suppressed without affecting reception sensitivity.

  In this embodiment, since a product of a certain bandwidth and duration is used as a threshold value, many unnecessary signals are not detected without affecting reception sensitivity, so that the work efficiency of radio wave monitoring work is improved. Contribute greatly. In addition, as a radio wave other than the communication signal, for example, power is large, but a spike-like radio wave with a short duration is received, it can be excluded from the detection target. Efficient monitoring of communication waves can be performed.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 Signal detection apparatus 11 Bandwidth and duration measurement part 12 Extraction signal detection part 13 Signal extraction part 14 Wideband signal delay part 100 Radio wave monitoring apparatus 101 AD converter 102 FFT part 103 Threshold judgment part 104 Bandwidth and duration measurement part 105 B · τ product determination unit 106 Wideband FIFO memory 107 DDC unit 108 Demodulation unit 109 Receiving antenna

Claims (15)

A bandwidth and duration measuring unit for measuring the bandwidth and duration of a received signal which is a wideband signal;
An extraction signal detector that detects an extraction signal based on a bandwidth time product that is a product of the measured bandwidth and duration;
A wideband signal delay unit for delaying the received signal as a wideband signal;
A signal extraction unit for extracting the detected extracted signal from the delayed received signal;
A signal detection apparatus comprising: The extracted signal detector determines a signal having a bandwidth time product equal to or greater than a predetermined set value as the extracted signal;
The signal detection apparatus according to claim 1. The bandwidth / duration measurement unit measures the bandwidth at a fixed measurement time interval,
The extracted signal detection unit obtains the bandwidth time product by multiplying the bandwidth by the measurement time interval;
The signal detection apparatus according to claim 1 or 2. The extracted signal detector further determines a signal having a bandwidth equal to or greater than a predetermined threshold as the extracted signal.
The signal detection apparatus according to any one of claims 1 to 3. The extracted signal detector further determines a signal having a duration equal to or greater than a predetermined threshold as the extracted signal;
The signal detection apparatus as described in any one of Claims 1 thru | or 4. The wideband signal delay unit delays the reception signal by a time required from the reception of the reception signal until the extraction signal is detected,
The signal detection apparatus according to any one of claims 1 to 5. The wideband signal delay unit stores the received signal in a storage unit, and outputs the signal before the delay time from the present among the received signals stored in the storage unit as the delayed received signal,
The signal detection device according to claim 6. Measure the bandwidth and duration of the received signal, which is a wideband signal,
Detecting an extracted signal based on a bandwidth time product that is a product of the measured bandwidth and duration;
Delay the received signal as a broadband signal,
Extracting the detected extracted signal from the delayed received signal;
Signal detection method. In the detection of the extraction signal, a signal having a bandwidth time product equal to or higher than a predetermined setting value is determined as the extraction signal.
The signal detection method according to claim 8. In the measurement of the bandwidth and the duration, the bandwidth is measured at a constant measurement time interval,
In the detection of the extracted signal, the bandwidth time product is obtained by multiplying the bandwidth by the measurement time interval.
The signal detection method according to claim 8 or 9. In the detection of the extracted signal, a signal having a bandwidth equal to or higher than a predetermined threshold is further determined as the extracted signal.
The signal detection method as described in any one of Claims 8 thru | or 10. In the detection of the extraction signal, a signal having a duration equal to or greater than a predetermined threshold is determined as the extraction signal.
The signal detection method as described in any one of Claims 8 thru | or 11. In the delay of the received signal, the received signal is delayed by a time required from when the received signal is received until the extracted signal is detected.
The signal detection method according to any one of claims 8 to 12. In the delay of the reception signal, the reception signal is stored in a storage unit, and among the reception signals stored in the storage unit, a signal before the delay time from the present is output as the delayed reception signal.
The signal detection method according to claim 13. A bandwidth and duration measuring unit for measuring the bandwidth and duration of a received signal which is a wideband signal;
An extraction signal detector that detects an extraction signal based on a bandwidth time product that is a product of the measured bandwidth and duration;
A wideband signal delay unit for delaying the received signal as a wideband signal;
A signal extraction unit for extracting the detected extracted signal from the delayed received signal;
A demodulator that demodulates the extracted signal in accordance with the modulation method of the extracted extracted signal;
A receiving device.

Images