JP5061205B2 - Modulation method identification circuit and modulation method identification method - Google Patents

Description

  The present invention relates to a modulation scheme identification circuit and a modulation scheme identification method, and more particularly to a modulation scheme identification circuit and a modulation scheme identification method for specifying a modulation scheme by a simple method.

  Cognitive radio is attracting attention in order to improve frequency utilization efficiency. In cognitive radio, the usage status of a frequency is grasped, and the modulation method is properly used according to the usage status of the frequency.

  In order to grasp the frequency utilization status in cognitive radio, it is necessary to specify the modulation method in the frequency band. When specifying a modulation method, a demodulation process is attempted using all of the assumed modulation methods, and the modulation method is determined based on whether or not demodulation is possible.

  On the other hand, an apparatus for automatically selecting a target radio wave from a plurality of received radio waves has been proposed (see, for example, Patent Document 1). The apparatus of Patent Document 1 synthesizes frequency components from a preset modulation method and modulation speed, scans the frequency band of the received signal, and determines whether there is a peak that matches the synthesized frequency distribution waveform. Is selected, the target radio wave is selected.

JP 2003-262670 A

  In order to attempt the demodulation process, a circuit for performing the demodulation process must be provided. Even if the apparatus of Patent Document 1 is used, it is necessary to demodulate the received signal, and thus a circuit for performing demodulation processing must be provided.

  If a circuit for performing demodulation processing is used when specifying a modulation system in a frequency band, a demodulation circuit is required for each modulation system. For this reason, the circuit for specifying the modulation method in the frequency band becomes large. Further, if demodulation processing is attempted with all modulation schemes and synchronization is performed in each demodulation processing, it takes time to specify the modulation scheme.

  Accordingly, an object of the present invention is to provide a modulation scheme identification circuit, a demodulation device, a modulation scheme identification method, and a demodulation method that can specify a modulation scheme without attempting demodulation processing.

  In wireless communication, APD (Amplitude Probability Distribution), that is, measurement of an amplitude probability distribution is performed in order to measure disturbing electromagnetic waves. The inventors have found that the amplitude probability distribution used in the measurement of the disturbing electromagnetic wave is different for each modulation method. Based on this discovery, the present invention is characterized by specifying a modulation scheme using an amplitude probability distribution.

  Specifically, the modulation scheme identification circuit according to the present invention includes an APD (Amplitude Probability Distribution) measurement unit (31) that measures an amplitude probability distribution of an input signal, and a database that stores amplitude probability distribution information corresponding to the modulation scheme. The unit (32) and the measurement information obtained from the amplitude probability distribution measured by the APD measurement unit are collated with the amplitude probability distribution information stored in the database unit, and the measurement information is obtained from the amplitude probability distribution information. And a collation unit (33) for selecting the most consistent amplitude probability distribution information.

  Since the APD measurement unit is provided, the amplitude probability distribution of the input signal can be measured. The amplitude probability distribution information for each modulation method is stored in the database unit, and the matching unit selects the amplitude probability distribution information that most closely matches the measurement information, whereby the modulation method can be specified. Here, the modulation system identification circuit according to the present invention uses an APD, and can specify a modulation system without performing demodulation processing. Therefore, the modulation system identification circuit according to the present invention can specify the modulation system without attempting demodulation processing.

In the modulation scheme identification circuit according to the present invention, the database unit stores an amplitude value at a predetermined time probability of an amplitude probability distribution corresponding to a modulation scheme as the amplitude probability distribution information, and the verification unit includes the APD. The amplitude value at the predetermined time probability of the amplitude probability distribution measured by the measurement unit is acquired as the measurement information, and the amplitude value acquired as the measurement information from the amplitude values stored in the database unit And the one having the smallest difference in amplitude value at the predetermined time probability may be selected.
According to the present invention, the collation unit can select the amplitude probability distribution information that most closely matches the measurement information from the amplitude probability distribution information. Since the amplitude value of the amplitude probability distribution is used, the calculation amount of the collation unit can be reduced.

In the modulation scheme identification circuit according to the present invention, the database unit stores an amplitude value at a predetermined time probability of an amplitude probability distribution corresponding to a modulation scheme as the amplitude probability distribution information, and the verification unit includes the APD. The amplitude value at the predetermined time probability of the amplitude probability distribution measured by the measurement unit is acquired as the measurement information, and the amplitude value acquired as the measurement information from the amplitude values stored in the database unit The one having a correlation coefficient closest to 1 or −1 may be selected.
According to the present invention, the collation unit can select the amplitude probability distribution information that most closely matches the measurement information from the amplitude probability distribution information. Since the amplitude value of the amplitude probability distribution is used, the calculation amount of the collation unit can be reduced. Further, since the correlation coefficient is used, it is possible to select amplitude probability distribution information having a strong linear relationship with the measurement information.

In the modulation scheme identification circuit according to the present invention, the database unit stores a coefficient of each order when the amplitude probability distribution corresponding to the modulation scheme is represented by a polynomial as the amplitude probability distribution information, and the collation unit includes the The coefficient of each order when the amplitude probability distribution measured by the APD measurement unit is expressed by a polynomial is acquired as the measurement information, and the coefficient acquired as the measurement information from the coefficients stored in the database unit You may select the thing with the smallest difference.
According to the present invention, the collation unit can select the amplitude probability distribution information that most closely matches the measurement information from the amplitude probability distribution information. In addition, since the coefficient of each order when the amplitude probability distribution is expressed by a polynomial is used, the number of parameters to be collated can be reduced.

  Specifically, the demodulator according to the present invention uses the modulation scheme identification circuit (21) according to the present invention and the modulation scheme corresponding to the amplitude probability distribution information selected by the modulation scheme identification circuit, to input the input signal. And a demodulation circuit (22) for demodulating the signal.

  Since the modulation system identification circuit according to the present invention is provided, the modulation system can be specified without attempting demodulation processing. Thereby, the demodulating device according to the present invention can specify the modulation method without trying the demodulation process. Further, since the demodulating device according to the present invention further includes a demodulating circuit, the demodulating method corresponding to the modulating method of the input signal can be demodulated.

  Specifically, the modulation scheme identification method according to the present invention refers to an APD (Amplitude Probability Distribution) measurement procedure (S101) for measuring an amplitude probability distribution of an input signal, and amplitude probability distribution information corresponding to the modulation scheme, A collation procedure (S102) for collating the measurement information obtained from the amplitude probability distribution measured by the APD measurement procedure with the amplitude probability distribution information, and selecting information that most closely matches the measurement information from the amplitude probability distribution information; , In order.

  Since the APD measurement procedure is included, the amplitude probability distribution of the input signal can be measured. In the verification procedure, the modulation probability can be identified by referring to the amplitude probability distribution information for each modulation method and selecting the amplitude probability distribution information that most closely matches the measurement information. Here, the modulation scheme identification method according to the present invention uses APD, and can specify a modulation scheme without performing demodulation processing. Therefore, the modulation scheme identification procedure according to the present invention can specify a modulation scheme without attempting demodulation processing.

In the modulation scheme identification method according to the present invention, in the verification procedure, the amplitude value at a predetermined time probability of the amplitude probability distribution is referred to as the amplitude probability distribution information, and the predetermined amplitude probability distribution measured by the APD measurement procedure is referred to. An amplitude value at a time probability of the first time is acquired as the measurement information, and the one having the smallest difference in amplitude value at the predetermined time probability from the acquired amplitude value is selected from the referenced amplitude values. Also good.
According to the present invention, the amplitude probability distribution information that most closely matches the measurement information can be selected from the amplitude probability distribution information in the verification procedure. Since the amplitude value of the amplitude probability distribution is used, the calculation amount of the collation unit can be reduced.

In the modulation scheme identification method according to the present invention, in the verification procedure, the amplitude value at a predetermined time probability of the amplitude probability distribution is referred to as the amplitude probability distribution information, and the predetermined amplitude probability distribution measured by the APD measurement procedure is referred to. May be acquired as the measurement information, and the one with the closest correlation coefficient with the acquired amplitude value may be selected from the referenced amplitude values.
According to the present invention, the amplitude probability distribution information that most closely matches the measurement information can be selected from the amplitude probability distribution information by executing the matching procedure. Since the amplitude value of the amplitude probability distribution is used, the amount of calculation in the matching procedure can be reduced. Further, since the correlation coefficient is used, it is possible to select amplitude probability distribution information having a strong linear relationship with the measurement information.

In the modulation method identification method according to the present invention, in the collation procedure, the amplitude probability distribution measured by the APD measurement procedure is referred to by referring to the coefficient of each order when the amplitude probability distribution is represented by a polynomial as the amplitude probability distribution information. A coefficient of each order when expressed in a polynomial may be acquired as the measurement information, and a coefficient having the smallest difference from the acquired coefficient may be selected from the referenced coefficients.
According to the present invention, the amplitude probability distribution information that most closely matches the measurement information can be selected from the amplitude probability distribution information in the verification procedure. In addition, since the coefficient of each order when the amplitude probability distribution is expressed by a polynomial is used, the number of parameters to be collated can be reduced.

The demodulation method according to the present invention includes a modulation scheme identification method according to the present invention, a demodulation procedure (S103) for demodulating the input signal using a modulation scheme corresponding to the amplitude probability distribution information selected in the collation procedure, In order.
Since the demodulation method according to the present invention includes the modulation scheme identification circuit according to the present invention, the modulation scheme can be specified without attempting demodulation processing. Thereby, the demodulation method according to the present invention can specify the modulation method without attempting the demodulation process. Moreover, since the demodulation method according to the present invention further includes a demodulation procedure, the input signal can be demodulated using a demodulation method corresponding to the modulation method of the input signal.

  The above inventions can be combined as much as possible.

  According to the present invention, it is possible to provide a modulation scheme identification circuit, a demodulation device, a modulation scheme identification method, and a demodulation method that can specify a modulation scheme without attempting demodulation processing.

An example of the communication apparatus which concerns on this embodiment is shown. It shows an example of an amplitude probability distribution information I _R. It is a flowchart which shows an example of the demodulation method which concerns on this embodiment. It shows an example of parameters for amplitude probability distribution information I _R and measurement information are amplitude values of the amplitude probability distribution. It shows an example of parameters for amplitude probability distribution information I _R and measurement information is a coefficient of each order of the time representing the amplitude probability distribution polynomial.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. In the present specification and drawings, the same reference numerals denote the same components.

FIG. 1 shows an example of a communication apparatus according to the present embodiment. The communication device 101 according to the present embodiment includes an antenna 11 and a demodulation device 12. Antenna 11, outputs an electric signal _{S K} to the demodulation unit 12 receives a radio signal _{S R.} Demodulator 12 uses a modulation method corresponding to the modulation scheme of the electric signal S _K, demodulates the electrical signal S _K.

The demodulation device 12 includes a modulation scheme identification circuit 21 and a demodulation circuit 22. Modulation type discrimination circuit 21 identifies the modulation scheme of the electric signal S _K. Demodulation circuit 22 uses a modulation scheme corresponding to the amplitude probability distribution information I _R for selecting the modulation type discrimination circuit 21, demodulates the input signal or an electrical signal S _K.

The modulation scheme identification circuit 21 includes an APD measurement unit 31, a database unit 32, and a collation unit 33. APD measuring unit 31, an input signal or by measuring the amplitude probability distribution _{I M} of the electric signal _{S K} outputs. Database unit 32 stores the amplitude probability distribution information I _R corresponding to the modulation scheme. Collating unit 33, by selecting the amplitude probability distribution information I _R that best matches the amplitude probability distribution I _M, identifies the modulation scheme of the electric signal S _K.

2 shows an example of an amplitude probability distribution information I _R. Amplitude probability distribution information _{I R} is, for example, an amplitude value (dB) versus time probability (%). Here, the time probability is also referred to as amplitude probability, but is referred to as time probability in the present application. Amplitude probability distribution information I _{R of} modulation scheme I _R -1, modulation scheme I _R -2, modulation scheme I _R -3, modulation scheme I _R -4, and modulation scheme I _R -5 is shown. The modulation method I _R −1 is π / 4 shift QPSK (Quadrature Phase Shift Keying). The modulation scheme I _R -2 is QPSK. The modulation method I _R -3 is BPSK (Binary Phase Shift Keying). The modulation scheme I _R -4 is 16QAM (Quadrature Amplitude Modulation). Modulation scheme I _R -5 is MSK (Minimum Shift Keying). For reference, the distribution of AWGN (Additive White Gaussian Noise) is also shown. By reading the amplitude value (dB) with respect to the time probability (%), it is possible to acquire the amplitude value with a predetermined time probability.

Test conditions of the amplitude probability distribution information I _R shown in FIG. 2 is as follows. The conditions on the transmission side are: the information source is a 15-stage pseudo-random code, the symbol rate is 0.4 kHz, the signal-to-noise ratio per bit is 40 dB, the modulation scheme I _R -1, the modulation scheme I _R -2, the modulation scheme The roll-off rate of I _R -3 and modulation scheme I _R -4 is 0.5. On the receiving side, the sampling frequency during AD conversion is 16 kHz, the resolution bandwidth during APD measurement is 1 kHz, and the sample length is 500 msec.

As shown in FIG. 2, the amplitude value (dB) with respect to the time probability (%) is different for each modulation method. In the present embodiment, displaying the amplitude probability distribution information I _R with a Rayleigh distribution. In the case of phase modulation shown in the modulation scheme I _R -1, the modulation scheme I _R -2, and the modulation scheme I _R -3, a difference in inclination appears at the inflection point reflected in the phase change between symbols. The quadrature amplitude modulation shown in the modulation method I _R -4 is a gentle curve with small undulations. Since the frequency modulation shown in the modulation method I _R- 5 has a constant envelope amplitude, it is almost linear. As described above, by displaying with the Rayleigh distribution, the identification of the modulation method can be made remarkable.

Amplitude probability distribution information I _R will vary by the matching process of the collation unit 33. If the collating unit 33 collates the amplitude value of the amplitude probability distribution, amplitude probability distribution information _{I R} is, for example, modulation scheme _I R _-1 shown in Fig. 2, _{I R} -2, I R _-3, I R -4 , I _R −5 with a predetermined time probability. Although the predetermined time probability is arbitrary, it is preferable to include a time probability that an inflection point appears in the modulation scheme I _R -1, the modulation scheme I _R -2, and the modulation scheme I _R -3. Such time probabilities are, for example, 50%, 60%, 70%, 80%, 90%, and 95%.

When the collation unit 33 collates the coefficients of the respective orders when the amplitude probability distribution is represented by a polynomial, the amplitude probability distribution information I _R is, for example, the modulation schemes I _R −1, I _R −2 and I shown in FIG. _{R -3,} I _{R -4,} a coefficient of each order expressed by a polynomial amplitude probability distribution of the _I R -5.

  The communication device 101 executes the demodulation method according to the present embodiment. FIG. 3 is a flowchart showing an example of the demodulation method according to the present embodiment. The demodulation method according to the present embodiment includes an APD measurement procedure S101, a matching procedure S102, and a demodulation procedure S103 in order. The modulation scheme identification method according to this embodiment includes an APD measurement procedure S101 and a matching procedure S102 in order.

In APD measurement procedure S101, APD measuring unit 31, the input signal or by measuring the amplitude probability distribution _{I M} of the electric signal _{S K} outputs.

In collating sequence S102, the matching section 33 refers to the amplitude probability distribution information I _R that is stored in the database unit 32, the measurement information and the amplitude probability distribution information obtained from the amplitude probability distribution I _M measured by APD measurement procedure S101 to match the I _R. Then, the matching unit 33 selects the best matching information in the measurement information from among the amplitude probability distribution information I _R.

4 shows an example of a parameter when the amplitude probability distribution information I _R and measurement information are amplitude values of the amplitude probability distribution. In this case, the modulation scheme identification circuit 21 operates as follows, for example.

The collation unit 33 refers to the amplitude value A _i at a predetermined time probability i stored in the database unit 32. Then, the matching unit 33 obtains the amplitude value B _i at a given time probability i of the amplitude probability distribution I _M to measure the APD measuring unit 31 as the measurement information. Then, a difference D _i of amplitude values at a predetermined time probability i between the amplitude value A _i stored in the database unit 32 and the amplitude value B _i acquired as measurement information is calculated.

The difference D _i is calculated for a plurality of time probabilities i. Further, the difference D _i is calculated for each of the modulation schemes I _R −1, I _R −2, I _R −3, I _R −4, and I _R −5. Then, among the amplitude values A _i of the respective modulation schemes I _R −1, I _R −2, I _R −3, I _R −4 and I _R −5, with a predetermined time probability i with respect to the amplitude value B _i. The one having the smallest difference D _{i in} amplitude values is selected.

For example, the sum S _A of the differences D _i between the time probabilities i is calculated.

Each modulation scheme _{I R -1, I R -2,} I R -3, I R -4, from among the sum _{S A} of _I R -5, selects a modulation scheme sum _{S A} is minimized. Thus, selecting the amplitude probability distribution information I _R that best matches the measurement information from among the amplitude probability distribution information I _R.

The amplitude value of the time probability that an amplitude probability distribution information I _R, can be directly match the amplitude value of the amplitude probability distribution I _M to measure the APD measuring section 31. For this reason, the amount of calculation in the collation part 33 can be reduced by simple calculation.

The amplitude value difference D _i may be the distance between the amplitude value A _i and the amplitude value B _i . In this case, the collation unit 33 calculates the distance between the amplitude value A _i and the amplitude value B _i, and each modulation method I _R -1, I _R -2, I _R -3, I _R -4, I _R- Of the five amplitude values A _i, the one having the smallest distance value may be selected. In the distance calculation, a calculation for weighting a coefficient to be emphasized may be executed.

Sum S _A is directly affected by the magnitude of the amplitude value of the electric signal S _K to be input to the APD measuring unit 31. Therefore, as the center of gravity of the amplitude probability distribution I _M to the output of the APD measuring unit 31 becomes constant value, the correction may be performed to move the amplitude value of the amplitude probability distribution I _M to the output of the APD measuring section 31.

As shown in FIG. 4, when the amplitude probability distribution information I _R and measurement information are amplitude, modulation type discrimination circuit 21, for example, operates as follows. The collation unit 33 refers to the amplitude value A _i at a predetermined time probability i of the amplitude probability distribution corresponding to the modulation method stored in the database unit 32. Then, the matching unit 33 obtains the amplitude value B _i at a given time probability i of the amplitude probability distribution I _M to measure the APD measuring unit 31 as the measurement information. Then, the collation unit 33 calculates a correlation coefficient R with the amplitude value B _i acquired as the measurement information from the amplitude value A _i stored in the database unit 32.

ここで、Ａ_ａは振幅値Ａ_ｉの相加平均であり、Ｂ_ａは振幅値Ｂ_ｉの相加平均である。

Here, A _a is an arithmetic average of amplitude values A _i , and B _a is an arithmetic average of amplitude values B _i .

The correlation coefficient R is calculated for each of the modulation schemes I _R -1, I _R -2, I _R -3, I _R -4, and I _R -5. The correlation coefficient R is closest to 1 or -1 among the correlation coefficients R of the modulation schemes I _R -1, I _R -2, I _R -3, I _R -4, and I _R -5. Select. Thus, selecting the amplitude probability distribution information I _R that best matches the measurement information from among the amplitude probability distribution information I _R.

The amplitude value of the time probability that an amplitude probability distribution information I _R, can be directly match the amplitude value of the amplitude probability distribution I _M to measure the APD measuring section 31. For this reason, the amount of calculation in the collation part 33 can be reduced by simple calculation.

5 shows an example of a parameter when the amplitude probability distribution information I _R and measurement information is a coefficient of each order of the time representing the amplitude probability distribution polynomial. Amplitude probability distribution information _{I R} is represented by _{A (x) = a 0 +} a 1 x + a 2 x 2 + ··· a n x n, measurement information _{B (x) = b 0 +} b 1 x + b 2 x 2 + · When represented by b _n x ⁿ , the modulation scheme identification circuit 21 operates as follows, for example.

The collation unit 33 refers to the coefficient a _j of each order j stored in the database unit 32. Then, the matching unit 33 obtains the coefficients b _j of each order j when representing the amplitude probability distribution I _M to measure the APD measuring unit 31 by a polynomial as the measurement information. Then, the matching unit 33 calculates the difference d _j of the coefficient of each order.

Then, the collation unit 33 selects, from the coefficients a _j stored in the database unit 32, the one having the smallest difference d _j from the coefficient b _j acquired as the measurement information. For example, the sum S _J of the differences d _j is taken.

This sum S _J is calculated for each of the modulation schemes I _R -1, I _R -2, I _R -3, I _R -4, and I _R -5. Then, the amplitude probability distribution information I _R of the smallest modulation scheme sum S _J, is selected as the most matched information to the measurement information. Thus, selecting the amplitude probability distribution information I _R that best matches the measurement information from among the amplitude probability distribution information I _R.

Note that the difference d _i between the coefficients of the respective orders may be a distance between the coefficient a _j and the coefficient b _j . In this case, the collation unit 33 calculates the distance between the coefficient a _j and the coefficient b _j and sets the modulation schemes I _R −1, I _R −2, I _R −3, I _R −4, and I _R −5. Of the coefficients a _j, the one with the smallest distance value may be selected. In the distance calculation, a calculation for weighting a coefficient to be emphasized may be executed.

The amplitude probability distribution information I _R by a coefficient of each order, it is possible to reduce the parameters to be used in selecting the amplitude probability distribution information I _R that best matches the measurement information. Thus, best match the selected amplitude probability distribution information I _R in the measurement information, it can be performed using a small memory capacity.

The demodulation steps S103, using the modulation scheme which corresponds to the amplitude probability distribution information I _R selected in matching procedure S102, demodulates the input signal. For example, modulation type discrimination circuit 21 identifies the modulation scheme _I R -1 of the electric signal _{S K,} and outputs the identification information _{I A} particular modulation scheme _I R -1 to the demodulation circuit 22. Demodulation circuit 22 uses a modulation scheme _I R -1 corresponding to the identification information _{I A,} demodulates the electrical signal _{S K.} Thus, the demodulation circuit 22 uses a modulation scheme I _R -1 which corresponds to the amplitude probability distribution information I _R for selecting the modulation type discrimination circuit 21, demodulates the input signal or an electrical signal S _K.

As described above, the modulation type discrimination circuit 21, by executing the APD measurement procedure S101 and verification procedures S102, it is possible to identify the modulation scheme of the radio signal S _R without attempting demodulation processing. Modulation type discrimination circuit 21 according to this embodiment, in order to determine the modulation scheme of the radio signal S _R by using the amplitude probability distribution can be specified in a short time modulation scheme using a circuit having a simple configuration. Further, as shown in FIG. 2, since the difference between the AWGN and the radio signal S _R becomes clear, even if there is noise in the radio signal S _R, is possible to determine the modulation scheme of the radio signal S _R it can.

As described above, the communication device 101 and the demodulation unit 21, by executing the APD measurement procedure S101 and verification procedure S102, similarly to the modulation type discrimination circuit 21, the modulation of the radio signal _{S R} without attempting demodulation processing The method can be specified.

The communication device 101 and the demodulation unit 12, by further performs demodulation steps S103, it can be demodulated using a modulation scheme corresponding to the modulation scheme of the radio signal S _R. Thus, it is possible to perform demodulation of the radio signal S _R efficiently.

  The present invention can be used in the information communication industry.

11: Antenna 12: Demodulator 21: Modulation method identification circuit 22: Demodulator circuit 31: APD measurement unit 32: Database unit 33: Verification unit 101: Communication device

Claims (10)

An APD (Amplitude Probability Distribution) measurement unit (31) for measuring an amplitude probability distribution of an input signal;
A database unit (32) for storing amplitude probability distribution information corresponding to the modulation method;
The measurement information obtained from the amplitude probability distribution measured by the APD measurement unit is collated with the amplitude probability distribution information stored in the database unit, and the amplitude probability distribution that most closely matches the measurement information from the amplitude probability distribution information A collation unit (33) for selecting information;
A modulation system identification circuit comprising: The database unit stores an amplitude value at a predetermined time probability of an amplitude probability distribution corresponding to a modulation method as the amplitude probability distribution information,
The collation unit acquires the amplitude value at the predetermined time probability of the amplitude probability distribution measured by the APD measurement unit as the measurement information, and the measurement value is obtained from the amplitude values stored in the database unit. The modulation system identification circuit according to claim 1, wherein the one having the smallest difference in amplitude value with the predetermined time probability from the amplitude value acquired as information is selected. The database unit stores an amplitude value at a predetermined time probability of an amplitude probability distribution corresponding to a modulation method as the amplitude probability distribution information,
The collation unit acquires the amplitude value at the predetermined time probability of the amplitude probability distribution measured by the APD measurement unit as the measurement information, and the measurement value is obtained from the amplitude values stored in the database unit. The modulation system identification circuit according to claim 1, wherein the one having a correlation coefficient with the amplitude value acquired as information closest to 1 or −1 is selected. The database unit stores, as the amplitude probability distribution information, a coefficient of each order when the amplitude probability distribution corresponding to the modulation method is represented by a polynomial.
The collation unit acquires, as the measurement information, a coefficient of each order when the amplitude probability distribution measured by the APD measurement unit is represented by a polynomial, and the measurement is performed from the coefficients stored in the database unit. The modulation system identification circuit according to claim 1, wherein the one having the smallest difference from the coefficient acquired as information is selected. A modulation system identification circuit (21) according to any one of claims 1 to 4,
A demodulation circuit (22) for demodulating the input signal using a modulation scheme corresponding to amplitude probability distribution information selected by the modulation scheme identification circuit;
A demodulator comprising: An APD (Amplitude Probability Distribution) measurement procedure (S101) for measuring the amplitude probability distribution of the input signal;
The amplitude probability distribution information corresponding to the modulation method is referred to, the measurement information obtained from the amplitude probability distribution measured in the APD measurement procedure is compared with the amplitude probability distribution information, and the measurement information is obtained from the amplitude probability distribution information. A matching procedure (S102) for selecting the most matching information;
The modulation system identification method which has these in order. In the verification procedure, the amplitude value at a predetermined time probability of the amplitude probability distribution is referred to as the amplitude probability distribution information, and the amplitude value at the predetermined time probability of the amplitude probability distribution measured by the APD measurement procedure is measured. The information obtained and selected as the information is selected from among the amplitude values that are referred to, the one having the smallest difference in amplitude value with the predetermined time probability from the acquired amplitude value. Modulation method identification method. In the verification procedure, the amplitude value at a predetermined time probability of the amplitude probability distribution is referred to as the amplitude probability distribution information, and the amplitude value at the predetermined time probability of the amplitude probability distribution measured by the APD measurement procedure is measured. The modulation system identification according to claim 6, wherein the correlation value with the acquired amplitude value is closest to 1 or -1 among the amplitude values acquired and referred to as information. Method. In the collation procedure, each order coefficient when the amplitude probability distribution measured by the APD measurement procedure is represented by a polynomial with reference to the coefficient of each order when the amplitude probability distribution is represented by a polynomial as the amplitude probability distribution information. The modulation method identification method according to claim 6, further comprising: selecting a coefficient having the smallest difference from the acquired coefficient from the referenced coefficients. The modulation method identification method according to any one of claims 6 to 9,
A demodulation procedure (S103) for demodulating the input signal using a modulation scheme corresponding to the amplitude probability distribution information selected in the matching procedure;
In order.

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