JP6868346B2 - Signal detection program, signal detection method and signal detection device - Google Patents

Description

The present invention relates to a signal detection program, a signal detection method, and a signal detection device.

Conventionally, as a method of detecting a signal propagating around the own device, a method of calculating a cross-correlation value between a known signal pattern such as a preamble pattern and a received signal is known. In such a device, it is determined that the desired signal has been received when the cross-correlation value exceeds the threshold value.

Japanese Unexamined Patent Publication No. 2009-278409

However, in the above-mentioned device, the cross-correlation value may be large when a signal other than the desired signal is received. There is a frequency deviation between the receiving device and the transmitting device due to a deviation of the mounted clock or the like. When the frequency deviation is corrected for the received signal and the cross-correlation value is calculated, the variation of signals other than the desired signal becomes small, and the cross-correlation value may become large. Therefore, a signal other than the desired signal may be erroneously detected as a desired signal, and the detection accuracy may decrease.

An object of the present invention is to provide a signal detection program, a signal detection method, and a signal detection device that can improve the detection accuracy of a desired signal.

In one embodiment, the signal detection program causes a computer to perform a process of generating a cross-correlation signal by cross-correlation calculation between the received signal and a known signal pattern. Further, the signal detection program causes the computer to execute a process of calculating the correction amount of the frequency deviation of the received signal based on the cross-correlation signal. Further, the signal detection program causes the computer to execute a process of calculating a cross-correlation value between the received signal and the known signal pattern whose frequency deviation is corrected by the correction amount. Further, the signal detection program causes the computer to execute a process of detecting the received signal including the known signal pattern based on the cross-correlation value.

As one aspect, it is possible to improve the detection accuracy of the desired signal.

FIG. 1 is a block diagram showing an example of the configuration of the signal detection device of the first embodiment. FIG. 2 is an explanatory diagram showing an example of the detection process of the signal detection device of the first embodiment. FIG. 3 is an explanatory diagram showing another example of the detection process of the signal detection device of the first embodiment. FIG. 4 is a flowchart showing an example of the detection process of the first embodiment. FIG. 5 is a block diagram showing an example of the configuration of a signal detection device as a comparative example. FIG. 6 is an explanatory diagram showing an example of the detection process of the signal detection device shown in FIG. FIG. 7 is an explanatory diagram showing another example of the detection process of the signal detection device shown in FIG. FIG. 8 is an explanatory diagram showing an example of the probability density distribution of the cross-correlation value. FIG. 9 is an enlarged view of a part of the probability density distribution of FIG. FIG. 10 is an explanatory diagram showing another example of the probability density distribution of the cross-correlation value. FIG. 11 is an enlarged view of a part of the probability density distribution of FIG. FIG. 12 is a block diagram showing an example of the configuration of the signal detection device of the second embodiment. FIG. 13 is a flowchart showing an example of the detection process of the second embodiment. FIG. 14 is an explanatory diagram showing an application example of the signal detection device. FIG. 15 is an explanatory diagram showing a hardware configuration of the signal detection device.

Hereinafter, examples of the signal detection program, the signal detection method, and the signal detection device disclosed in the present application will be described in detail with reference to the drawings. The disclosed technology is not limited by the present embodiment. In addition, the examples shown below may be appropriately combined as long as they do not cause a contradiction.

FIG. 1 is a block diagram showing an example of the configuration of the signal detection device 1 of the first embodiment. The signal detection device 1 shown in FIG. 1 includes an antenna 10, an RF (Radio Frequency) unit 20, and a signal detection unit 30. The antenna 10 receives radio waves propagating around the signal detection device 1.

The RF unit 20 performs filtering processing, amplification processing, and the like on the radio waves received by the antenna 10. The RF unit 20 mixes the received radio waves with signals having different phases by 90 degrees to generate a received I signal and a received Q signal. Hereinafter, the received I signal and the received Q signal are collectively referred to as a received signal. The received signal is a two-phase shift keying (BPSK) signal.

Specifically, the RF unit 20 performs the arithmetic processing shown in the following equation (1) on the received radio wave s (t) to generate the received signal S (t).

Here, A is the signal amplitude, and Δwt is the component of the frequency deviation caused by the fact that the clock frequency of the RF unit 20 is deviated from the transmitting side.

The signal detection unit 30 detects a desired signal included in the received signal. The signal detection unit 30 includes a generation unit 31, a correction amount calculation unit 32, a correction unit 33, a correlation value calculation unit 34, a detection unit 35, and a storage unit 36.

The generation unit 31 performs a cross-correlation calculation between the received signal and the known signal pattern to generate a cross-correlation signal. The known signal pattern is a signal pattern known by the signal detection device 1, such as a preamble signal or a pilot signal. The known signal pattern is stored in the storage unit 36. The generation unit 31 acquires a known signal pattern from the storage unit 36.

The generation unit 31 divides the received signal S (t) by a predetermined unit length such as a bit unit, and performs a correlation calculation on the received signal. The generation unit 31 performs a cross-correlation calculation on the received signal and the known signal pattern using the following equation (2) to generate cross-correlation signals S (i) (i are bit numbers and positive numbers).

Here, Δt is a predetermined unit length, and r (t) is a known signal pattern.

The correction amount calculation unit 32 calculates the correction amount θ of the frequency deviation of the received signal based on the cross-correlation signal generated by the generation unit 31.

The correction unit 33 corrects the cross-correlation signal based on the correction amount θ calculated by the correction amount calculation unit 32, and generates a correction signal. The correction unit 33 corrects the cross-correlation signal S (i) generated by the generation unit 31 using the following equation (3), and generates the correction signal S_mod (i).

Here, Δw is a correction amount corresponding to the phase difference θ.

The correlation value calculation unit 34 performs a sum calculation of the correction signal S_mod (i) using the following equation (4). As a result, the correlation value calculation unit 34 calculates the cross-correlation value C between the received signal whose frequency deviation is corrected by the correction amount θ and the known signal pattern.

The detection unit 35 detects a received signal including a known signal pattern as a desired signal based on the cross-correlation value C calculated by the correlation value calculation unit 34. The storage unit 36 stores a known signal pattern.

Next, the detection process performed by the signal detection device 1 of the first embodiment will be described. The detection process when a desired signal is received will be described with reference to FIG. FIG. 2 is an explanatory diagram showing an example of the detection process of the signal detection device 1 of the first embodiment.

FIG. 2A is a diagram in which the received signal is mapped to the IQ plane. Each point shown in FIG. 2A indicates each bit of the received signal, and the number included in the point indicates a bit number. That is, the point indicated by "2" in FIG. 2A indicates the second bit of the received signal. Here, it is assumed that the signal detection device 1 has received the received signal of the bit string of "10100".

Since the received signal is a BPSK signal, when it is mapped to the IQ plane, it is ideally mapped on the I axis as in the known signal pattern shown in FIG. 2 (b). However, in reality, each bit rotates around the origin and varies on the circumference with the signal amplitude as the radius due to the influence of the frequency deviation caused by the fact that the clock frequency of the RF unit 20 deviates from the transmitting side. ..

Next, the generation unit 31 of the signal detection device 1 performs a cross-correlation calculation between the received signal and the known signal pattern. In this case, if the known signal pattern is "1", the phase of the cross-correlation signal is the same as that of the received signal. When the known signal pattern is "0", the known signal pattern is represented by, for example, "-1" in the IQ plane, so that the phase of the cross-correlation signal is a phase in which the phase of the received signal is advanced by 180 degrees.

Therefore, when the generation unit 31 performs the cross-correlation calculation between the received signal including the same pattern as the known signal pattern and the known signal pattern, as shown in FIG. 2C, the cross-correlation signal has a predetermined phase difference of each bit. The signal has an angle θ1. The predetermined angle θ1 is the frequency deviation. The correction amount calculation unit 32 uses, for example, the average value of the phase difference θ1 of each bit as the correction amount of the frequency deviation.

The correction unit 33 corrects the cross-correlation signal based on the correction amount θ1 and generates the correction signal shown in FIG. 2D. The correlation value calculation unit 34 performs a sum calculation of each bit of the correction signal, and calculates a cross-correlation value between the received signal after frequency deviation correction and the known signal pattern. Here, each bit of the correction signal has a value close to “1” as shown in FIG. 2 (d). Therefore, when a received signal including a known signal pattern is received, the cross-correlation value becomes a large value.

The detection unit 35 compares the cross-correlation value with the threshold value Th1. The detection unit 35 determines that the desired signal has been detected when the cross-correlation value is the threshold value Th1 or more.

Subsequently, the detection process when a signal other than the desired signal (hereinafter, referred to as an interference signal) is received will be described with reference to FIG. FIG. 3 is an explanatory diagram showing another example of the detection process of the signal detection device 1 of the first embodiment. Here, it is assumed that the signal detection device 1 has received the interference signal of the bit string of "11000".

The generation unit 31 generates a cross-correlation signal between the interference signal and the known signal pattern. Since the bit patterns of the interference signal and the known signal pattern are different, as shown in FIG. 3C, the phase difference of each bit of the cross-correlation signal has different angles. The correction amount calculation unit 32 sets the average value of the phase differences of each bit of the cross-correlation signal as the correction amount θ2 of the frequency deviation. Here, since the phase difference of each bit is different, the calculated correction amount θ2 is a value different from the actual frequency deviation.

The correction unit 33 corrects the cross-correlation signal with the correction amount θ2, and generates a correction signal. Since the phase difference of each bit of the cross-correlation signal varies and the cross-correlation signal is corrected with a correction amount θ2 different from the actual frequency deviation, the correction signal is an IQ plane as shown in FIG. 3 (d). It becomes a signal that varies above. The correlation value calculation unit 34 calculates the cross-correlation value by performing a sum calculation of each bit of the correction signal. As shown in FIG. 3D, since each bit of the correction signal varies on the two dimensions of the IQ plane, there is a high probability that the cross-correlation value will be a small value close to “0”. In this case, the detection unit 35 determines that the received signal is not a desired signal when the cross-correlation value is less than the threshold value Th1 based on the comparison result between the cross-correlation value and the threshold value Th1.

As described above, the signal detection device 1 of the first embodiment performs the cross-correlation calculation between the received signal and the known signal pattern, and then corrects the frequency deviation. As a result, the signal detection device 1 can reduce the cross-correlation value when the interference signal is received, and can suppress erroneous detection of detecting the interference signal as a desired signal. Therefore, the signal detection device 1 can improve the detection accuracy of the desired signal.

Next, the operation of the signal detection device 1 of the first embodiment will be described. FIG. 4 is a flowchart showing an example of the detection process of the first embodiment. The detection process shown in FIG. 4 is repeatedly executed, for example, every time the signal detection device 1 receives a received signal.

In FIG. 4, the RF unit 20 in the signal detection device 1 generates a received I signal and a received Q signal from the received radio wave (step S11). The signal detection unit 30 in the signal detection device 1 performs a cross-correlation calculation between the received signal and the known signal pattern for each predetermined unit length (step S12), and generates a cross-correlation signal. The signal detection unit 30 calculates a correction amount, which is a frequency deviation component, based on the cross-correlation signal (step S13).

The signal detection unit 30 corrects the cross-correlation signal with the correction amount calculated in step S13 (step S14). The signal detection unit 30 sums the corrected cross-correlation signals and calculates the cross-correlation value (step S15). The signal detection unit 30 determines the detection / non-detection of the desired signal based on the cross-correlation value calculated in step S15 (step S16), and ends the process.

The signal detection unit 30 of the first embodiment generates a cross-correlation signal by a cross-correlation calculation between the received signal and a known signal pattern, and calculates a correction amount of the frequency deviation of the received signal based on the cross-correlation signal. Further, the signal detection unit 30 calculates the cross-correlation value between the received signal whose frequency deviation is corrected by the correction amount and the known signal pattern, and detects the received signal including the known signal pattern based on the cross-correlation value. As a result, the signal detection unit 30 aims to reduce the type I error of erroneously detecting the interference signal as a desired signal. Then, the signal detection unit 30 aims to improve the detection accuracy of the desired signal by reducing the type I error.

Here, with reference to FIGS. 5 to 7, as a comparative example of the signal detection device 1, the signal detection device 100 that corrects the frequency deviation and then performs the cross-correlation calculation will be described. FIG. 5 is a block diagram showing an example of the configuration of the signal detection device 100 as a comparative example. The same configuration as that of the signal detection device 1 in FIG. 1 is designated by the same reference numeral, and the description of the overlapping configuration and operation will be omitted.

The signal detection unit 130 of the signal detection device 100 includes a square calculation unit 131, a correction amount calculation unit 132, a correction unit 133, and a correlation value calculation unit 134.

The square calculation unit 131 squares the received signal and generates a square signal. The correction amount calculation unit 132 calculates the correction amount θ based on the squared signal. The correction unit 133 corrects the received signal with the correction amount θ calculated by the correction amount calculation unit 132. The correlation value calculation unit 134 performs a cross-correlation calculation between the corrected received signal and the known signal pattern, and calculates the cross-correlation value.

FIG. 6 is an explanatory diagram showing an example of the detection process of the signal detection device 100 shown in FIG. FIG. 6 shows an example when the signal detection device 100 receives the desired signal “10100”. As shown in FIG. 6B, the squared signal generated by the squared calculation unit 131 is a signal in which the phase difference of each bit is twice the frequency deviation (2θ). The correction amount calculation unit 132 calculates the correction amount θ by multiplying the phase difference of each bit of the squared signal by 1/2. The correction unit 133 corrects the received signal by delaying the phase of each bit of the received signal shown in FIG. 6A by a correction amount θ. As shown in FIG. 6C, each bit of the corrected received signal varies on the I axis.

The correlation value calculation unit 134 calculates the cross-correlation value between each bit of the corrected received signal and each bit of the known signal pattern. In the example shown in FIG. 6, the cross-correlation value becomes large, and the detection unit 35 detects a desired signal.

FIG. 7 is an explanatory diagram showing another example of the detection process of the signal detection device 100 shown in FIG. FIG. 7 shows an example when the signal detection device 100 receives the interference signal “11000”. As shown in FIG. 7B, the squared signal generated by the squared calculation unit 131 is a signal in which the phase difference of each bit is twice the frequency deviation (2θ) as in FIG. 6B. Therefore, the correction amount calculation unit 132 calculates the correction amount θ corresponding to the frequency deviation.

The correction unit 133 corrects the received signal by delaying the phase of each bit of the received signal shown in FIG. 7A by a correction amount θ. As shown in FIG. 7 (c), the first and second bits of the corrected received signal are scattered in the positive direction of the I axis, and the third to fifth bits are scattered in the negative direction of the I axis.

As described above, in the detection process by the signal detection device 100, when the interference signal is received, the bit of the received signal after correction varies on one dimension of the I axis. Therefore, the cross-correlation value calculated by the correlation value calculation unit 134 has a high probability of becoming a large value as compared with the case where the bits vary in two dimensions. That is, in the cross-correlation value for the interference signal, there is a high probability that the cross-correlation value calculated by the signal detection device 1 will be smaller than the cross-correlation value calculated by the signal detection device 100. Therefore, the signal detection device 1 detects the desired signal with higher accuracy than the case where the frequency deviation is corrected and the cross-correlation calculation is performed by performing the cross-correlation calculation on the received signal and then correcting the frequency deviation. can do.

FIG. 8 is an explanatory diagram showing an example of the probability density distribution of the cross-correlation value. FIG. 8 shows an example of the probability density distribution when the known signal pattern is 72 bits. The probability density distributions P1 to P4 in FIG. 8 are probability density distributions of cross-correlation values when the signal detection devices 1 and 100 receive the desired signal. When the desired signal is received, the probability density distributions of the cross-correlation values calculated by the signal detection devices 1 and 100 are equal. The probability density distributions P1 to P4 are probability density distributions of cross-correlation values when the signal-to-noise ratio SN is different from each other. The lower the signal-to-noise ratio SN, the smaller the median value of the probability density distribution. If the propagation environment of the received signal is poor, for example, there are many interference signals, the signal-to-noise ratio SN becomes low, and the probability that the cross-correlation value also becomes small increases.

The probability density distribution P5 in FIG. 8 is the probability density distribution of the cross-correlation value when the signal detection device 100 receives the interference signal. As described above, when the signal detection device 100 corrects the frequency deviation, the corrected signal varies in one dimension. It is known that the probability density distribution as a result of performing the sum operation of random values that vary on one dimension is generally a one-sided Gaussian distribution. Therefore, the probability density distribution P5 has a one-sided Gaussian distribution.

The probability density distribution P6 in FIG. 8 is the probability density distribution of the cross-correlation value when the signal detection device 1 receives the interference signal. As described above, when the signal detection device 1 corrects the frequency deviation, the correction signal varies in two dimensions. It is known that the probability density distribution as a result of performing the sum operation of random values that vary in two dimensions is generally a Rayleigh distribution. Therefore, the probability density distribution P5 becomes a Rayleigh distribution.

FIG. 9 is an enlarged view of a part A of the probability density distribution of FIG. Here, in the signal detection device 1, for example, the ratio of type I errors that erroneously detect an interference signal as a desired signal is 0.1% of the total, and the ratio of type II errors that erroneously detect a desired signal as an interference signal is It is assumed that the threshold value Th1 is set so as to be 0.1% of the whole. In this case, each ratio of the region E1 surrounded by the probability density distribution P6 and the threshold value Th1 and the region E2 surrounded by the probability density distribution P4 having a signal-to-noise ratio SN of −2.5 dB and the threshold value Th1 is the probability density distribution P4. , 0.1% or less with respect to the entire region of P6.

When the signal detection device 100 detects a desired signal using the threshold value Th1, the interference signal is erroneously detected as a desired signal in the region E3 surrounded by the probability density distribution P5 and the threshold value Th1. From this, it can be seen that when the signal detection device 1 detects a desired signal using the same threshold value Th1, erroneous detection can be suppressed as compared with the signal detection device 100. In this way, the signal detection device 1 can improve the detection accuracy of the desired signal.

Further, it is assumed that the signal detection device 100 sets the threshold value Th2 so that the ratio of the type I error and the type 2 error is 0.1%. In this case, the signal detection device 100 sets the threshold value Th2 for the probability density distribution P3 and the probability density distribution P5 having a signal-to-noise ratio SN of -1 dB.

In this way, when the signal detection devices 1 and 100 set the threshold values Th1 and Th2, respectively, the signal detection device 1 sets the threshold value Th1 for the probability density distribution P4 having a lower signal-to-noise ratio SN than the signal detection device 100. be able to. That is, the reception sensitivity of the signal detection device 1 can be improved from -1 dB to −2.5 dB as compared with the signal detection device 100. As a result, the signal detection device 1 can detect a desired signal with high accuracy even when the propagation environment is poor, such as when there are many interference signals.

FIG. 10 is an explanatory diagram showing another example of the probability density distribution of the cross-correlation value. FIG. 10 shows an example of the probability density distribution when the known signal pattern is 144 bits. The probability density distributions P11 to P14 in FIG. 10 show the probability density distributions when the signal-to-noise ratios SN are −1.5 dB, -3 dB, −4.5 dB, and −6 dB, respectively. Since the known signal pattern is longer than that in FIG. 8, the signal detection devices 1 and 100 can detect a desired signal even when the signal-to-noise ratio SN is lower.

FIG. 11 is an enlarged view of a part B of the probability density distribution of FIG. The signal detection device 1 sets a threshold value Th11 in which the ratio of type I and type II errors (regions E5 and E6 in FIG. 11) is 0.1%. Further, the signal detection device 100 sets a threshold value Th12 at which the rate of type 1 and type 2 errors is 0.1%. The signal detection device 1 can set a threshold value Th11 at which the rate of type I and type II errors is 0.1% even when the signal-to-noise ratio SN is −6 dB. On the other hand, the signal detection device 100 can set a threshold value Th12 at which the rate of type I and type II errors is 0.1% even if the signal-to-noise ratio SN is −4.5 dB.

In this way, when the threshold values Th11 and Th12 in which the ratios of the first and second type errors are the same are set, the signal detection device 1 has a threshold value for a probability density distribution having a lower signal noise ratio SN than the signal detection device 100. Th11 can be set. That is, the reception sensitivity of the signal detection device 1 can be improved from −4.5 dB to -6 dB as compared with the signal detection device 100.

Further, as shown in FIGS. 8 to 11, the signal noise ratio SN of the detectable signal is determined by the correlation length for which the correlation calculation is performed. Since the amount of processing increases as the correlation length increases, it is preferable to select the shortest correlation length within the range in which the application requirements can be achieved, and the required correlation length can be derived by calculating the probability density distribution. As described in the first embodiment, the rate of type I error and type II error is 0.1%, and when it is desired to detect a signal having a signal noise ratio of SN = −2.5 dB, the correlation length is set to 72 bits. .. Further, when the ratio of type 1 error and type 2 error is 0.1% and it is desired to detect a signal having a signal noise ratio of SN = 6 dB, the correlation length is set to 144 bits. In this way, the shortest correlation length required to execute the cross-correlation calculation can be derived according to the rate of type I error and type II error and the required signal-to-noise ratio. In this case, the generation unit 31 sets the correlation length for performing the cross-correlation calculation based on the derived shortest correlation length. The generation unit 31 executes a cross-correlation calculation between the received signal and the known signal pattern with the set correlation length.

The signal detection unit 30 of the first embodiment corrects the frequency deviation with respect to the cross-correlation signal. However, frequency deviation may be performed on the received signal, and an embodiment in this case will be described below as Example 2.

FIG. 12 is a block diagram showing an example of the configuration of the signal detection device 1A of the second embodiment. The same configuration as that of the signal detection device 1 of the first embodiment is designated by the same reference numeral, and the description of the overlapping configuration and operation will be omitted.

The difference between the signal detection device 1 shown in FIG. 1 and the signal detection device 1A shown in FIG. 12 is that the correction unit 33A and the correlation value calculation unit 34A are provided instead of the correction unit 33 and the correlation value calculation unit 34. ..

The correction unit 33A corrects the frequency deviation of the received signal output by the RF unit 20 with the correction amount calculated by the correction amount calculation unit 32. The correction unit 33A generates a correction reception signal as a correction reception signal.

The correlation value calculation unit 34A calculates the cross-correlation value C between the corrected reception signal and the known signal pattern using the following equation (5).

Here, Δt2 is the second unit length, and corresponds to, for example, an integral multiple of the sample rate of the received signal. That is, Δt2 is shorter than the predetermined unit length Δt of the cross-correlation calculation performed by the generation unit 31. Further, Ae ^{js (t)} is a corrected reception signal and is represented by the following equation (6).

Substituting Eq. (6) into Eq. (5) yields the same results as Eq. (4). In this way, even if the correction unit 33A corrects the frequency deviation with respect to the received signal, the signal detection unit 30 of the signal detection device 1A has the same detection accuracy of the desired signal as the signal detection unit 30 of the signal detection device 1. Can be improved.

This is because the correction amount θ calculated by the correction amount calculation unit 32 is the frequency deviation component θ1 when the desired signal is received, whereas the phase difference θ2 is different from the frequency deviation component when the interference signal is received. This is to become. By calculating the correction amount θ of the frequency deviation by performing the cross-correlation calculation in this way, the cross-correlation value between the corrected interference signal and the known signal pattern becomes a stochastically small value, and the detection accuracy of the desired signal Can be improved.

By making the second unit length Δt2 of the cross-correlation calculation performed by the correlation value calculation unit 34A shorter than the predetermined unit length Δt of the cross-correlation calculation performed by the generation unit 31, the calculation accuracy of the cross-correlation value can be improved. it can. As a result, the detection accuracy of the desired signal can be improved.

Next, the operation of the signal detection device 1A of the second embodiment will be described. FIG. 13 is a flowchart showing an example of the detection process of the second embodiment. The same processing as that of the signal detection device 1 of the first embodiment is designated by the same reference numerals, and the description of the overlapping configuration and operation will be omitted.

The correction unit 33A of the signal detection device 1A corrects the received signal with the correction amount calculated in step S13, and generates the corrected reception signal (step S21). The correlation value calculation unit 34A of the signal detection device 1A calculates the cross-correlation value between the corrected reception signal and the known signal pattern for each second unit length (step S22).

The signal detection unit 30 of the second embodiment executes a process of correcting the frequency deviation based on the correction amount with respect to the received signal. Further, as a process of calculating the cross-correlation value, the signal detection unit 30 calculates the cross-correlation value by performing a cross-correlation calculation between the received signal corrected based on the correction amount and the known signal pattern. As a result, false detection of the interference signal can be suppressed, and the detection accuracy of the desired signal can be improved.

In each of the above embodiments, the generation unit 31 performs a cross-correlation calculation for each bit as a predetermined unit length, but the present invention is not limited to this. The generation unit 31 may perform cross-correlation calculation for each integral multiple of the sample rate shorter than the bit rate, for example.

Further, each component of each of the illustrated parts does not necessarily have to be physically configured as shown in the figure. That is, the specific form of distribution / integration of each part is not limited to the one shown in the figure, and all or part of them are functionally or physically distributed / integrated in arbitrary units according to various loads and usage conditions. Can be configured. For example, the generation unit 31 and the correction amount calculation unit 32 may be integrated. Further, the illustrated processes are not limited to the above order, and may be performed simultaneously or in a different order as long as the processing contents do not contradict each other.

Further, the various processing functions performed by each device may be executed in whole or in any part on the CPU (or a microcomputer such as an MPU or a MCU (Micro Controller Unit)). Further, various processing functions may be executed in whole or in any part on a program analyzed and executed by a CPU (or a microcomputer such as an MPU or MCU) or on hardware by wired logic. Not to mention the good things.

By the way, the signal detection devices 1 and 1A described in each of the above embodiments can be applied to an environment in which devices having different wireless communication standards transmit and receive wireless signals. Therefore, an application example of the signal detection device 1 will be described below. FIG. 14 is an explanatory diagram showing an application example of the signal detection device 1. Although an application example of the signal detection device 1 will be described here, the signal detection device 1A can also be applied in the same manner.

As shown in FIG. 14, around the signal detection device 1, the first access point (first AP) 11A and the first station (first STA) 11S are communicating according to the first wireless communication standard. Further, the second access point (second AP) 12A and the second station (second STA) 12S are communicating according to the second wireless communication standard. The third access point (third AP) 13A and the third station (third STA) 13S are communicating according to the third wireless communication standard.

The signal detection device 1 stores, for example, a preamble pattern of the first wireless communication standard as a known signal pattern in the storage unit 36 in advance. When the signal detection device 1 receives the preamble signal transmitted / received between the first access point 11A and the first station 11S, the signal detection device 1 detects the preamble signal as a desired signal by performing cross-correlation calculation with a known signal pattern. .. As a result, the signal detection device 1 can estimate the traffic amount of the wireless signal transmitted / received according to the first wireless communication standard with high accuracy, for example.

The signal detection device 1 reduces the traffic amount of the first wireless communication standard, for example, when the estimated traffic amount is large. Alternatively, the signal detection device 1 switches to communication using another channel. As a result, the signal detection device 1 can appropriately manage the traffic volume of the first wireless communication standard. In this way, the signal detection device 1 can be applied to a system that measures the traffic volume of a predetermined wireless communication standard.

Further, each part of the signal detection devices 1 and 1A of each of the above embodiments can be configured by, for example, a software defined radio. Therefore, in the following, an example of the software defined radio constituting each part of the above-described first embodiment and the signal detection device 1 will be described. FIG. 15 is an explanatory diagram showing a hardware configuration of the signal detection device 1. Although the hardware configuration of the signal detection device 1 will be described here, the signal detection device 1A can also be configured in the same manner.

As shown in FIG. 15, the signal detection device 1 includes an RF (Radio Frequency) circuit 201, a CPU 301, a ROM (Read Only Memory) 302, and a RAM (Random Access Memory) 303.

Under such a hardware configuration, as an example, the RF unit 20 is realized by the RF circuit 201. Programs corresponding to each process executed by the generation unit 31, the correction amount calculation unit 32, the correction unit 33, the correlation value calculation unit 34, and the detection unit 35 are recorded in the ROM 302, and each program is executed by the CPU 301. Will be done. Further, the storage unit 36 is realized by the RAM 303. In this way, the functions of each part of the signal detection unit 30 are realized by the CPU 301, the ROM 302, and the RAM 303.

Further, the functional unit executed by the signal detection unit 30 can also be realized by, for example, a terminal such as a personal computer, a tablet terminal, or a smartphone. In this case, each program does not need to be recorded in the ROM 302. For example, the terminal may read and execute the program stored in the storage medium that can be read by the terminal. The storage medium that can be read by the terminal corresponds to, for example, a portable recording medium such as a CD-ROM, a DVD disk, or a USB memory, a semiconductor memory such as a flash memory, a hard disk drive, or the like. Further, the program may be stored in a device connected to a public line, the Internet, a LAN, or the like, and the terminal may read the program from these and execute the program.

1 Signal detection device 10 Antenna 20 RF unit 30 Signal detection unit 31 Generation unit 32 Correction amount calculation unit 33 Correction unit 34 Correlation value calculation unit 35 Detection unit

Claims (7)

A cross-correlation signal is generated by cross-correlation calculation between the received signal and a known signal pattern.
Based on the cross-correlation signal, the correction amount of the frequency deviation of the received signal is calculated.
A correction signal is generated by correcting the cross-correlation signal using the correction amount.
The correction amount received signal after correcting the frequency deviation using a cross-correlation value between the known signal pattern is calculated by the sum calculating said correction signal,
A signal detection program characterized by having a computer execute each process of comparing the calculated cross-correlation value with a threshold value and detecting the received signal including the known signal pattern based on the comparison result. As a process for generating the cross-correlation signal,
The signal detection program according to claim 1, wherein a cross-correlation calculation between the received signal and the known signal pattern is executed for each predetermined unit length. As a process for generating the cross-correlation signal,
Derived the shortest correlation length required to execute the cross-correlation calculation according to the rate of type 1 error and type 2 error, and the required signal-to-noise ratio.
The signal detection program according to claim 2, wherein a correlation length for performing cross-correlation calculation is set based on the shortest correlation length. The received signal is
The signal detection program according to any one of claims 1 to 3, wherein the signal is a two-phase shift keying (BPSK) signal. The known signal pattern is
It is a preamble signal of a predetermined wireless communication standard,
As a process of detecting the received signal including the known signal pattern,
The signal detection program according to any one of claims 1 to 4, wherein the received signal of the predetermined wireless communication standard is detected by detecting the received signal including the known signal pattern. The computer
A cross-correlation signal is generated by cross-correlation calculation between the received signal and a known signal pattern.
Based on the cross-correlation signal, the correction amount of the frequency deviation of the received signal is calculated.
A correction signal is generated by correcting the cross-correlation signal using the correction amount.
The correction amount received signal after correcting the frequency deviation using a cross-correlation value between the known signal pattern is calculated by the sum calculating said correction signal,
A signal detection method comprising comparing the calculated cross-correlation value with a threshold value and executing each process of detecting the received signal including the known signal pattern based on the comparison result. A generator that generates a cross-correlation signal by performing a cross-correlation calculation between the received signal and a known signal pattern.
A correction amount calculation unit that calculates a correction amount of the frequency deviation of the received signal based on the cross-correlation signal,
A correction unit that generates a correction signal by correcting the cross-correlation signal using the correction amount, and a correction unit.
A correlation value calculating unit for calculating by the correction amount received signal after correcting the frequency deviation using a cross-correlation value between the known signal pattern and sum calculation of said correction signal,
A signal detection device comprising a detection unit that compares the calculated cross-correlation value with a threshold value and detects the received signal including the known signal pattern based on the comparison result.

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