JP2001111644A - Modulation system automatic identification receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a modulation system automatic identification receiver applicable to an existing communication system, rich in flexibility and having an automatic identification system. SOLUTION: This modulation system automatic identification receiver is provided with a frequency conversion section that converts a received signal into a base band frequency band signal, a symbol position estimate section that estimates a symbol position of the received signal to output estimated symbol position information, an instantaneous amplitude value extract section that extracts an instantaneous amplitude of the received signal to output it, a standard deviation calculation section that calculates the standard deviation information of the instantaneous amplitude of the received signals to output it, an identification processing section that compares the standard deviation information with a characteristic standard deviation information of the instantaneous amplitude values corresponding respectively to each of a plurality of modulation systems that are set and stored and provides an output of modulations system identification result information, and a demodulation section that selects a demodulation system corresponding to the modulation system of the received signal to demodulate the received signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a receiver provided with a demodulation method module that can support a plurality of modulation methods. In particular, it relates to a general-purpose demodulation technology that is considered to play an important role in future wireless communication technology. As a function required to realize the general-purpose demodulation technique, there is an automatic identification function of a modulation scheme. The modulation scheme identification function is located at a step before the data demodulation unit, and calculates parameters necessary for demodulation by calculation.

[0002]

2. Description of the Related Art In conventional wireless communication, the modulation system is fixed, and it is not necessary to identify the modulation system. On the other hand, at present, with the diversification of communication systems, studies are being made on making the modulation system variable.

FIG. 1 is a system diagram relating to the identification of a modulation system. According to FIG. 1, two schemes are conceivable: an identification information embedding scheme in which modulation information is incorporated in a transmission signal in advance, and an automatic identification scheme for automatically identifying a modulation scheme.

[0004]

The identification information embedding method is as follows.
Compared to the automatic identification method, it is superior in easiness of processing and identification speed, but a new communication method needs to be determined. In addition, it is inferior in versatility in that it cannot be applied to a communication system that has already been standardized.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a modulation type automatic identification receiver having an automatic identification method which is applicable to existing communication systems and has high flexibility.

[0006]

Therefore, according to the modulation type automatic identification receiver of the present invention, a frequency converter for receiving a modulation signal from an arbitrary transmitter and converting it into a reception signal in a base band frequency band. A symbol position estimating unit that receives a received signal converted into a baseband frequency band by a frequency converting unit, estimates a symbol position of the received signal, and outputs estimated symbol position information, And an instantaneous amplitude value extraction unit that inputs and outputs the instantaneous amplitude value at the estimated symbol position of the received signal, and an estimated symbol position that is the output of the instantaneous amplitude value extraction unit. A standard deviation calculator for inputting an instantaneous amplitude value and calculating and outputting standard deviation information of the instantaneous amplitude value at the estimated symbol position of the received signal; The standard deviation information of the instantaneous amplitude value which is the force is input, and the modulation method of the received signal is identified by comparing with the characteristic standard deviation value of the instantaneous amplitude value corresponding to each of a plurality of modulation methods set and stored in advance. , An identification processing unit that outputs modulation scheme identification result information, a baseband frequency band received signal from a frequency conversion unit and estimated symbol position information from a symbol position estimation unit, and a modulation scheme identification from an identification processing unit. A demodulation unit that selects a demodulation method corresponding to the modulation method of the received signal based on the result information, and demodulates the received signal according to the demodulation method. This makes it possible to distinguish between a multi-level modulation scheme such as a multi-level modulation scheme such as QAM and a frequency modulation scheme such as GMSK, or a multi-level modulation scheme such as QAM and a phase modulation scheme such as QPSK, and other modulation schemes. It becomes possible.

According to the modulation type automatic identification receiver of the present invention, a frequency converter for receiving a modulated signal from an arbitrary transmitter and converting it into a signal in a baseband frequency band, A received signal converted into a band is input, a symbol position estimating unit that estimates a symbol position of the received signal and outputs estimated symbol position information, and a received signal and estimated symbol position information output by the symbol position estimating unit. And an instantaneous phase value extraction unit that extracts and outputs an instantaneous phase value at the estimated symbol position of the received signal, and an instantaneous phase value at the estimated symbol position output from the instantaneous phase value extraction unit. A standard deviation calculator for calculating and outputting the standard deviation information of the instantaneous phase value at the estimated symbol position; Input the standard deviation information of the instantaneous phase value and compare it with the characteristic standard deviation value of the instantaneous phase value corresponding to each of a plurality of modulation methods set and stored in advance to identify the modulation method of the received signal, An identification processing unit that outputs identification result information, a baseband frequency band received signal from the frequency conversion unit and estimated symbol position information from the symbol position estimation unit are input, and modulation scheme identification result information from the identification processing unit is input. And a demodulation unit for selecting a demodulation method corresponding to the modulation method of the received signal and demodulating the received signal by the selected demodulation method. Thereby, GMSK
Frequency modulation method that smoothly changes the phase of QA
A multi-level modulation scheme such as M or a frequency modulation scheme that smoothly changes the phase such as GMSK, and a phase modulation scheme such as QPSK such as a frequency modulation scheme that smoothly changes the phase and other modulation schemes Identification becomes possible.

According to the modulation type automatic identification receiver of the present invention, a frequency converter for receiving a modulation signal from an arbitrary transmitter and converting the signal into a signal in a baseband frequency band, A received signal converted into a band is input, a symbol position estimating unit that estimates a symbol position of the received signal and outputs estimated symbol position information, and a received signal and estimated symbol position information output by the symbol position estimating unit. And an instantaneous amplitude value and an instantaneous phase value extraction unit for extracting and outputting an instantaneous amplitude value and an instantaneous phase value at the estimated symbol position of the received signal, and an estimated symbol output from the instantaneous amplitude value and the instantaneous phase value extraction unit. The instantaneous amplitude value and the instantaneous phase value at the position are input, and the standard deviation information of the instantaneous amplitude value and the standard deviation information of the instantaneous phase value at the estimated symbol position of the received signal are obtained. A standard deviation calculator for calculating and outputting, and standard deviation information of instantaneous amplitude value and standard deviation information of instantaneous phase value at an estimated symbol position, which are outputs of the standard deviation calculator, are inputted, and a plurality of preset and stored preset values are stored. Characteristic standard deviation value of instantaneous amplitude value and characteristic standard deviation value of instantaneous phase value corresponding to each modulation method, standard deviation information and instantaneous phase value of instantaneous amplitude value at estimated symbol position calculated by standard deviation calculation unit The identification processing unit that identifies the modulation scheme of the received signal by comparing the standard deviation information of the received signal and outputs modulation scheme identification result information, and the received signal in the baseband frequency band from the frequency conversion unit and the symbol position estimation unit Of the estimated symbol position information, and selects a demodulation method corresponding to the modulation method of the received signal based on the modulation method identification result information from the identification processing unit, and receives by the demodulation method. Those having a demodulator for demodulating the issue. This makes it possible to identify which modulation method is used from a multi-level modulation method such as QAM, a frequency modulation method such as GMSK that smoothly changes the phase, or a phase modulation method such as QPSK.

An automatic identification receiver for a modulation system according to another embodiment of the present invention includes an antenna unit for receiving a modulation signal, a reception amplifier unit for amplifying the received modulation signal, and a baseband frequency for converting the frequency of the modulation signal to a baseband frequency. A frequency converting unit for converting, a symbol position estimating unit for estimating a symbol position of the modulated signal, an instantaneous amplitude value for extracting an instantaneous amplitude value at the symbol position and an instantaneous phase value at the symbol position, and an instantaneous phase value extracting unit. A standard deviation calculator for calculating a standard deviation of the extracted instantaneous amplitude value and a standard deviation of a phase difference value between successive symbols; and a standard for an instantaneous amplitude value at an estimated symbol position of a modulation signal to be identified in advance. The position on the two-dimensional plane represented by coordinate values, which is a set of the deviation and the standard deviation of the phase difference value between successive symbols, is defined as a plurality of patterns. Is stored for each said modulation scheme,
From the received signal, an instantaneous amplitude value at the estimated symbol position and a phase value at the symbol position are extracted, and a standard deviation of the extracted instantaneous amplitude value at the estimated symbol position and a standard deviation of the phase difference value between the consecutive symbols are calculated. Then, the received signal, the position on a two-dimensional plane represented by coordinate values as a set of the standard deviation of the instantaneous amplitude value and the standard deviation of the phase difference value between consecutive symbols at the estimated symbol position, The distance from the position of the pattern of each modulated signal is calculated, and the received signal is represented by a coordinate value that sets a standard deviation of an instantaneous amplitude value and a standard deviation of a phase difference value between consecutive symbols at the estimated symbol position as a set. The identification processing unit that outputs the modulation method of the pattern located at the shortest distance from the position on the two-dimensional plane to be identified as the identification result, and modulates based on the identification result And a demodulator for demodulating the issue.
This makes it possible to automatically identify and demodulate the multi-level modulation signal, the frequency modulation signal whose phase changes smoothly, and the phase modulation signal.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 2 is a block diagram of a modulation type automatic identification receiver according to the present invention. The modulated signal received by the antenna is amplified by a receiving amplifier, and the frequency of the amplified received signal is converted to a base band by a frequency conversion unit.
Next, in the symbol position estimating unit, the accumulation batch demodulation method (reference document [1]: Yu Miyake, et al., "Timing extraction method for accumulation batch demodulation method with greatly reduced computational complexity", IEICE Transactions BI Vol.J72-BI No.9 pp.754-76
1, September 1989) to estimate the symbol position of the received signal. The instantaneous amplitude value at the symbol position estimated here is extracted by the instantaneous amplitude value extraction unit. Next, based on the standard deviation of the instantaneous amplitude value calculated by the standard deviation calculation unit, the identification processing unit identifies the multi-level modulation signal and the frequency modulation signal or the phase modulation signal. Demodulation is performed in the demodulation unit based on the result estimated in the identification processing unit, and the baseband signal is restored.

FIG. 3 is a block diagram of another embodiment of a modulation type automatic identification receiver according to the present invention. FIG. 2 differs from FIG. 2 in that an instantaneous amplitude value extractor is provided, whereas FIG. 3 is provided with an instantaneous phase value extractor. In FIG. 3, the instantaneous phase value at the symbol position estimated by the symbol position estimating unit is extracted by the instantaneous phase value extracting unit. Next, based on the standard deviation of the phase difference value between consecutive symbols calculated in the standard deviation calculation unit, in the identification processing unit, a frequency modulation signal whose phase changes smoothly, a multi-level modulation signal or a phase modulation signal, Identify. Based on the result estimated in the identification processing unit, demodulation processing is performed in the demodulation unit,
The baseband signal is restored.

FIG. 4 is a block diagram of another embodiment of a modulation type automatic identification receiver according to the present invention. FIG. 4 has both the configurations of FIGS. 2 and 3. The instantaneous amplitude value and instantaneous phase value at the symbol position estimated by the symbol position estimating unit are extracted by the instantaneous amplitude value / instantaneous phase value extracting unit. Next, based on the standard deviation of the instantaneous amplitude value calculated by the standard deviation calculation unit and the standard deviation of the phase difference value between consecutive symbols, the discrimination processing unit uses a frequency-modulated signal whose phase changes smoothly, Identify a modulated signal or a phase modulated signal. Demodulation is performed in the demodulation unit based on the result estimated in the identification processing unit, and the baseband signal is restored.

While the instantaneous amplitude value of the multi-level modulation signal changes greatly for each symbol, the distribution of the instantaneous amplitude values of the frequency modulation signal and the phase modulation signal is considered to concentrate on one peak. Therefore, by using the standard deviation of the instantaneous amplitude value at the estimated symbol position as the feature amount, it becomes possible to discriminate the multi-level modulation signal from the frequency modulation signal or the phase modulation signal.

When considering GMSK which is widely used in the frequency modulation system, the phase between symbols changes smoothly. In comparison, the multilevel modulation signal or the phase modulation signal has a larger phase change between symbols. Therefore, by using the standard deviation of the phase difference value between consecutive symbols as the feature amount, it becomes possible to discriminate a frequency modulation signal whose phase changes smoothly from a multi-level modulation signal or a phase modulation signal.

The inventors actually extracted the instantaneous amplitude value at the estimated symbol position of the modulated signal by simulation, and identified the multi-level modulated signal using the nearest neighbor determination method.

FIG. 5 is an explanatory diagram of the positional relationship between the patterns of each modulation method when the nearest neighbor determination method is used.

The nearest neighbor determination method is one of the identification methods performed by using the extracted feature amount (reference document [2]: Kenichiro Ishii, Osamu Ueda, Eisaku Maeda, Hiroshi Murase, "Easy-to-understand pattern recognition", 1st edition, 1st printing, Ohm Publishing Office). The nearest neighbor determination method is a method in which patterns of each modulation scheme are arranged in advance in a feature space, and identification is performed based on a distance between each arranged pattern and a pattern of a received signal. The nearest neighbor determination method is
The process is relatively simple, and by increasing the number of patterns, a somewhat high identification rate can be obtained.
As an example, considering the processing in the identification processing unit in the configuration example 3 of the receiver in FIG. 4, the standard deviation of the instantaneous amplitude value and the phase difference value between consecutive symbols at the estimated symbol position of the modulation signal to be identified are determined in advance. The positions on a two-dimensional plane represented by coordinate values, which are a set of the standard deviation of the two, are arranged in the feature space as a pattern of each modulation method. Then, the position on the two-dimensional plane represented by coordinate values as a set of the standard deviation of the instantaneous amplitude value and the standard deviation of the phase difference value between consecutive symbols at the estimated symbol position of the received signal is Determine whether it is closest to the pattern.

The feature amounts used in the identification processing of FIG.
This is the standard deviation of the instantaneous amplitude value at the estimated symbol position. The modulation schemes targeted here are GMSK, π / 4Q
PSK, 16QAM. These are typical modulation schemes actually used in each of the frequency modulation signal, the phase modulation signal, and the multi-level modulation signal. As the identification method, a nearest neighbor determination method capable of maintaining a somewhat high identification rate by increasing the number of patterns of each modulation scheme arranged in the feature space in advance is used. GMSK, π / 4-QPSK is
The standard deviation of the instantaneous amplitude value at the estimated symbol position is almost zero. In 16QAM, the standard deviation of the instantaneous amplitude value is 2.
62. The instantaneous amplitude value is normalized assuming that 2/5 of the in-phase component value of the envelope amplitude having the smallest level among the envelope amplitudes existing at three levels in 16QAM is 1. The number of observation symbols at the time of pattern creation for each modulation method was 500. After arranging the patterns of the respective modulation schemes in this manner, the position on the one-dimensional axis represented by the standard deviation value of the instantaneous amplitude value at the estimated symbol position of the received signal is calculated, and each modulation is calculated from the received signal pattern. The distance to the system pattern is calculated, and the modulation system of the pattern located closest to the received signal pattern is output as the estimation result. As shown in FIG. 5, when the standard deviation of the instantaneous amplitude value of the received signal is 1.85, the estimation result is 16QAM.

FIG. 6 is a graph of the simulation result of FIG. In FIG. 6, the horizontal axis is the SNR, and the vertical axis is the identification rate. The number of samples was 2000, and the number of observed symbols per sample was 5. As a result, the identification rate of 16QAM did not largely depend on SNR, and was around 80%. It is considered that this identification rate can be improved by increasing the number of observation symbols per sample or by increasing the number of patterns of each modulation scheme to be arranged in advance.

FIG. 7 is an explanatory diagram of the positional relationship between the patterns of each modulation method when the nearest neighbor determination method is used. The feature amount used in the identification processing of FIG. 7 is the standard deviation of the phase difference value between consecutive symbols. Actually, the instantaneous phase value at the estimated symbol position of the modulation signal was extracted by simulation, and the frequency modulation signal whose phase smoothly changed was identified using the nearest neighbor determination method. The modulation schemes targeted here are GMSK, π / 4-QPSK, 16QA
M. These are frequency modulated signals, phase modulated signals,
This is a typical modulation scheme actually used in each of the multi-level modulation signals. As the identification method, a nearest neighbor determination method capable of maintaining a somewhat high identification rate by increasing the number of patterns of each modulation scheme arranged in the feature space in advance is used.
In GMSK, the standard deviation of the phase difference value between consecutive symbols is substantially zero. The standard deviation of the phase difference between consecutive symbols of 16QAM and π / 4-QPSK is 0.87 (r
ad) and 0.78 (rad). The number of observation symbols at the time of pattern creation for each modulation method was 500. After arranging the patterns of the respective modulation schemes in this way, the position on the one-dimensional axis represented by the standard deviation of the phase difference value between consecutive symbols of the received signal is calculated, and from the received signal pattern, The distance to the pattern is calculated, and the modulation scheme of the pattern located closest to the received signal pattern is output as the estimation result. As shown in FIG. 7, the standard deviation of the phase difference between consecutive symbols of the received signal is 0.26 (ra
If d), the estimation result is GMSK.

FIG. 8 is a graph of the simulation result of FIG. In FIG. 8, the horizontal axis is the SNR, and the vertical axis is the identification rate. The number of samples was 2000, and the number of observed symbols per sample was 5. As a result, the identification rate of GMSK was 93% or more when the SNR was 20 dB or more. It is considered that this identification rate can be improved by increasing the number of observation symbols per sample or by increasing the number of patterns of each modulation scheme to be arranged in advance.

FIG. 9 is an explanatory diagram of the positional relationship between the patterns of each modulation method when the nearest neighbor determination method is used. The feature amounts used in the identification processing of FIG. 9 are the standard deviation of the instantaneous amplitude value at the estimated symbol position and the standard deviation of the phase difference value between consecutive symbols. Actually, by simulation, the instantaneous amplitude value at the estimated symbol position and the phase value at the estimated symbol position of the modulated signal are extracted, and the frequency modulation signal whose phase changes smoothly using the nearest neighbor determination method, the phase modulation signal, Discrimination from the multi-level modulation signal was performed.
The modulation method targeted here is GMSK, π / 4-QPS
K, 16QAM. These are typical modulation schemes actually used in each of the frequency modulation signal, the phase modulation signal, and the multi-level modulation signal. As the identification method, a nearest neighbor determination method capable of maintaining a somewhat high identification rate by increasing the number of patterns arranged in the feature space in advance is used.
In GMSK, both features are almost equal to 0, and π / 4−
In QPSK, the standard deviation of the instantaneous amplitude value at the estimated symbol position was almost 0, and the standard deviation of the phase difference value between consecutive symbols was 0.78 (rad). 16QAM is
The standard deviation of the instantaneous amplitude value was 2.62, and the standard deviation of the phase difference value between consecutive symbols was 0.87 (rad). The instantaneous amplitude value is normalized with 1/5 of the in-phase component value of the envelope amplitude having the smallest level among the envelope amplitudes existing at three levels in 16QAM. The number of observation symbols at the time of pattern creation for each modulation method was 500. After arranging the patterns of the respective modulation schemes in this manner, a two-dimensional plane represented by a coordinate value having a set of a standard deviation of an instantaneous amplitude value and a standard deviation of a phase difference value between consecutive symbols at an estimated symbol position of a received signal. The above position is calculated, the distance from the position of the pattern of the received signal to the pattern of each modulation method is calculated, and the modulation method of the pattern located closest to the pattern of the received signal is output as an estimation result. . FIG.
The standard deviation of the instantaneous amplitude value of the received signal is 0.7
6. The standard deviation of the phase difference value between consecutive symbols is 0.26.
If (rad), the estimation result is GMSK.

FIG. 10 is a graph of the simulation result of FIG. In FIG. 10, the horizontal axis is the SNR, and the vertical axis is the identification rate. 200 samples per plot
0, and the number of observation symbols per sample was 5. As a result, the identification rate of 16QAM did not largely depend on SNR, and was around 80%. On the other hand, GMSK and π / 4-Q
Regarding PSK, when the SNR is 20 dB or more, the identification rate is 93% or more. It is considered that this identification rate can be improved by increasing the number of observation symbols per sample or by increasing the number of patterns of each modulation scheme to be arranged in advance.

In the above, one embodiment of the modulation type automatic identification receiver of the present invention has been described. However, various changes, modifications and omissions of the technical idea and scope of the present invention can be easily made by those skilled in the art. Can be done. Therefore, the above description is merely an example and is not intended to be limiting. The invention is limited only as defined by the appended claims and equivalents thereof.

Finally, a description will be given of the accumulated batch demodulation method of the above-mentioned reference. FIG. 11 is a block diagram of the accumulation batch demodulation method. The accumulation collective demodulation method is roughly divided into a part for performing quadrature detection with carrier asynchronous and obtaining temporary demodulated data, a part for estimating a symbol point position from a spectrum of the amplitude square sum of the temporary demodulated data, and It is divided into portions for estimating carrier frequency information by removing the modulation phase component from the phase change of the temporary demodulated data.

The processing performed in the symbol position estimating section will be described below. The effects of the carrier frequency offset and the initial phase error remain in the provisionally demodulated data obtained by quadrature detection of the digital modulation signal while the carrier is asynchronous. When these provisional demodulated data are subjected to A / D sampling and the sum of squares is obtained, only the data symbol components remain. Since only the symbol rate component is dominant in the sum of squares of the tentative demodulated data, when the spectrum is obtained by performing FFT on the symbol rate component, the peak becomes the symbol rate component. Generally, the sampling at the time of A / D conversion and the timing of the symbol are asynchronous, so that the peak of the spectrum does not completely match the component of the symbol rate. Therefore, the larger of the peak component and the two components adjacent to the peak component is extracted, and the two components are regarded as symbol rate components, and the inverse FF is determined.
Apply T. When the inverse FFT is applied to the symbol rate component extracted in this way, the obtained real part and imaginary part become the phase component of the symbol rate, and if the inverse tangent of both is obtained, the phase component φ of the symbol rate is obtained. Ts: sampling period, nTs: n-th sampling time, f _b :
Symbol rate frequency, θ: Assuming a phase difference, φ (nTs) = [2πf _b nTs + θ] mod 2π.

Here, the point where φ (nTs) = π is at the center position of each symbol. Since sampling at the time of A / D conversion is generally asynchronous with the timing of one symbol,
No point exactly satisfies such a condition. Therefore, a point where φ (nTs) = π was obtained by linear interpolation using two points before and after. The instantaneous amplitude at the symbol position estimated in this way and the phase component of the temporary demodulated data are
Further, it was obtained by a fourth-order Lagrange interpolation formula for interpolating using data of four points before and after which is a smooth function.

Finally, yet another embodiment of the present invention is shown in FIG.
This will be described with reference to FIGS. 12, 13 and 14. In the automatic identification processing unit of the receiver in FIG. 4, the modulated signal received by the antenna unit is amplified by the reception amplifier unit,
The frequency of the amplified modulated signal is converted to a baseband frequency in a frequency conversion unit. Next, the symbol position estimating unit estimates the symbol position of the modulated signal using the accumulated batch demodulation method. The instantaneous amplitude value and instantaneous phase value at the symbol position estimated here are extracted by an instantaneous amplitude value / instantaneous phase value extraction unit. Next, based on the standard deviation of the instantaneous amplitude value and the standard deviation of the phase difference value between consecutive symbols calculated by the standard deviation calculation unit, each modulation system is identified by the identification processing unit. Demodulation is performed in the demodulation unit based on the result estimated in the identification processing unit, and the baseband signal is restored.

In each of the above-described embodiments, the patterns of the respective modulation schemes are arranged one by one in the feature space, and the identification processing is performed. In the present embodiment, a plurality of patterns of each modulation method are arranged in the feature space, and identification processing is performed. First, FIG. 12 shows the target modulation schemes as GMSK, BPSK, π / 4-QPSK, and QP.
An example of a feature space when SK and 16QAM are used and patterns of each modulation scheme are arranged one by one. The axes constituting the feature space are the standard deviation of the instantaneous amplitude value at the estimated symbol position and the variance of the phase difference value between consecutive symbols. FIG. 13 shows an example of a feature space when 100 patterns of each modulation scheme are arranged. Compared to the feature space shown in FIG. 12, the feature space shown in FIG. 13 has a more demarcated boundary line reflecting the actual data, and has a better pattern than the case where one pattern of each modulation scheme is arranged. In addition, it is possible to improve the identification rate characteristics. Using each of the feature spaces shown in FIGS. 12 and 13, a simulation for identifying each modulation scheme was performed. In the result of FIG. 14, the horizontal axis is the number of observed symbols, and the vertical axis is the identification rate characteristic. Assuming a Gaussian channel as a simulation condition, the SNR is 20d
B. The number of observation symbols at the time of pattern creation is 500,
The number of simulations is 10,000. As can be seen from FIG. 14, by increasing the number of patterns, the identification rate characteristics of each modulation scheme are improved.

[0031]

As described above in detail, according to the present invention, there is provided a modulation type automatic identification receiver having an automatic identification method, which is applicable to existing communication systems and has high flexibility. be able to.

Therefore, according to the present invention, a multilevel modulated signal can be automatically identified and demodulated. That is, QA
A multi-level modulation scheme such as M and a frequency modulation scheme such as GMSK,
Alternatively, it is possible to distinguish between a multi-level modulation scheme such as a multi-level modulation scheme such as QAM and a phase modulation scheme such as QPSK and other modulation schemes.

Further, according to the present invention, it is possible to automatically identify and demodulate a frequency modulation signal whose phase changes smoothly. That is, the frequency modulation method such as GMSK and Q
It is possible to distinguish between a frequency modulation method that smoothly changes the phase, such as a multi-level modulation method such as AM, a frequency modulation method such as GMSK, and a phase modulation method such as QPSK, and other modulation methods.

Further, according to the present invention, it is possible to automatically identify and demodulate a multi-level modulation signal, a frequency modulation signal whose phase changes smoothly, and a phase modulation signal. That is, QA
It is possible to identify which modulation scheme is used from a multi-level modulation scheme such as M, a frequency modulation scheme such as GMSK, or a phase modulation scheme such as QPSK.

Further, the radio signal receiver described in claim 4 is equipped with the automatic identification means of the modulation signal described in another embodiment, and by using this receiver,
A multi-level modulation signal, a frequency modulation signal whose phase changes smoothly, and a phase modulation signal can be automatically identified and demodulated.

As described above, the present invention is effective for realizing a general-purpose demodulator that can cope with a change in communication format.
It can be applied to identification and removal of interference waves, monitoring of illegal radio waves, and the like.

[Brief description of the drawings]

FIG. 1 is a system diagram relating to modulation scheme identification.

FIG. 2 is a configuration diagram of a first embodiment of a modulation scheme automatic identification receiver according to the present invention.

FIG. 3 is a configuration diagram of a second embodiment of a modulation scheme automatic identification receiver according to the present invention.

FIG. 4 is a configuration diagram of a third embodiment of a modulation scheme automatic identification receiver according to the present invention.

FIG. 5 is an explanatory diagram of a positional relationship between patterns of each modulation scheme when the nearest neighbor determination method according to the present invention is used.

FIG. 6 is a graph showing a simulation result of FIG. 5;

FIG. 7 is an explanatory diagram of a positional relationship between patterns of each modulation scheme when the nearest neighbor determination method according to the present invention is used.

FIG. 8 is a graph of a simulation result of FIG. 7;

FIG. 9 is an explanatory diagram of a positional relationship between patterns of each modulation scheme when the nearest neighbor determination method according to the present invention is used.

FIG. 10 is a graph showing a simulation result of FIG. 9;

FIG. 11 is a configuration diagram of an accumulation batch demodulation method.

FIG. 12 shows the target modulation schemes being GMSK, BPSK,
FIG. 6 is a diagram illustrating a feature space when π / 4-QPSK, QPSK, and 16QAM are used, and one pattern of each modulation scheme is arranged.

FIG. 13 shows modulation schemes to be used, such as GMSK, BPSK,
FIG. 6 is a diagram illustrating a feature space when π / 4-QPSK, QPSK, and 16QAM are used and 100 patterns of each modulation scheme are arranged.

FIG. 14 is a diagram illustrating identification rate characteristics of each modulation scheme when each of the feature spaces shown in FIGS. 12 and 13 is used.

Claims (4)

[Claims] 1. A receiver comprising a demodulation module capable of supporting a plurality of modulation schemes, wherein the receiver receives a modulation signal from an arbitrary transmitter and converts the modulation signal into a reception signal in a baseband frequency band. A converting unit, a symbol position estimating unit that receives a received signal converted into a baseband frequency band by the frequency converting unit, estimates a symbol position of the received signal, and outputs estimated symbol position information, And an estimated symbol position information output by the symbol position estimating unit, and an instantaneous amplitude value extracting unit that extracts and outputs an instantaneous amplitude value at the estimated symbol position of the received signal; The instantaneous amplitude value at the estimated symbol position, which is the output of the received signal, is input, and the standard deviation information of the instantaneous amplitude value at the estimated symbol position of the received signal is calculated and output. A standard deviation calculator, which inputs standard deviation information of the instantaneous amplitude value at the estimated symbol position which is the output of the standard deviation calculator, and outputs the instantaneous amplitude at the estimated symbol position corresponding to each of a plurality of modulation schemes set and stored in advance. An identification processing unit that identifies a modulation method of the received signal by comparing with a characteristic standard deviation value of an amplitude value, and outputs modulation method identification result information, and a baseband frequency band reception signal from the frequency conversion unit, Estimated symbol position information from the symbol position estimating unit is input, and the modulation method identification result information from the identification processing unit selects a demodulation method corresponding to the modulation method of the received signal, and according to the demodulation method, A modulation type automatic identification receiver, comprising: a demodulation unit for demodulating a received signal. 2. A receiver comprising a demodulation module capable of supporting a plurality of modulation schemes, comprising: receiving a modulated signal from an arbitrary transmitter and converting the signal into a signal in a baseband frequency band. A symbol position estimating unit that receives a reception signal converted into a baseband frequency band by the frequency conversion unit, estimates a symbol position of the reception signal, and outputs estimated symbol position information, , An estimated symbol position information output by the symbol position estimation unit, an instantaneous phase value extraction unit that extracts and outputs an instantaneous phase value at the estimated symbol position of the received signal, The instantaneous phase value at the estimated symbol position, which is the output, is input, and the standard deviation information of the instantaneous phase value at the estimated symbol position of the received signal is calculated and output. A quasi-deviation calculator, inputting the standard deviation information of the instantaneous phase value at the estimated symbol position which is the output of the standard deviation calculator, and characterizing the instantaneous phase values respectively corresponding to a plurality of modulation schemes set and stored in advance. An identification processing unit that identifies a modulation scheme of the received signal by comparing with a standard deviation value, and outputs modulation scheme identification result information, and a baseband frequency band received signal from the frequency conversion unit and the symbol position estimation unit. And a demodulation unit that selects a demodulation method corresponding to the modulation method of the received signal based on the modulation method identification result information from the identification processing unit, and demodulates the received signal according to the demodulation method. A modulation type automatic identification receiver characterized by comprising: 3. A receiver comprising a demodulation module capable of supporting a plurality of modulation schemes, comprising: receiving a modulated signal from an arbitrary transmitter, and converting the modulated signal into a signal in a baseband frequency band. A symbol position estimating unit that receives a reception signal converted into a baseband frequency band by the frequency conversion unit, estimates a symbol position of the reception signal, and outputs estimated symbol position information, An instantaneous amplitude value and an instantaneous phase value extracting unit that inputs the estimated symbol position information output by the symbol position estimating unit, extracts and outputs the instantaneous amplitude value and the instantaneous phase value at the estimated symbol position of the received signal. Inputting an instantaneous amplitude value and an instantaneous phase value at an estimated symbol position which are outputs of the instantaneous amplitude value and instantaneous phase value extraction unit, and A standard deviation calculator for calculating and outputting the standard deviation information of the instantaneous amplitude value and the standard deviation information of the instantaneous phase value at the position; and the standard deviation information of the instantaneous amplitude value at the estimated symbol position output from the standard deviation calculator. And the standard deviation information of the instantaneous phase value, and the characteristic standard deviation value of the instantaneous amplitude value and the characteristic standard deviation value of the instantaneous phase value respectively corresponding to a plurality of modulation schemes set and stored in advance, The modulation scheme of the received signal is identified by comparing the standard deviation information of the instantaneous amplitude value and the standard deviation information of the instantaneous phase value at the estimated symbol position calculated by the standard deviation calculation unit, and the modulation scheme identification result information is obtained. An identification processing unit to be output, and a baseband frequency band reception signal from the frequency conversion unit and estimated symbol position information from the symbol position estimation unit are input, and the identification processing unit A demodulation section for selecting a demodulation scheme corresponding to the modulation scheme of the received signal based on the modulation scheme identification result information and demodulating the received signal according to the demodulation scheme. . 4. A receiver comprising a module of a demodulation system capable of supporting a plurality of modulation systems, comprising: an antenna unit for receiving a modulation signal; a reception amplifier unit for amplifying the received modulation signal; A frequency converter for converting the frequency of the signal to a baseband frequency; a symbol position estimator for estimating a symbol position of the modulated signal; an instantaneous amplitude for extracting an instantaneous amplitude value at the symbol position and an instantaneous phase value at the symbol position A value and an instantaneous phase value extracting unit; a standard deviation calculating unit that calculates a standard deviation of the extracted instantaneous amplitude value and a standard deviation of a phase difference value between consecutive symbols; On a two-dimensional plane represented by coordinate values, a set of the standard deviation of the instantaneous amplitude value at the symbol position and the standard deviation of the phase difference value between successive symbols The position is stored as a plurality of patterns for each of the modulation schemes, and from the received signal, the instantaneous amplitude value at the estimated symbol position and the phase value at the symbol position are extracted, and the instantaneous value at the extracted estimated symbol position is extracted. A standard deviation of an amplitude value and a standard deviation of a phase difference value between the consecutive symbols are calculated, and a set of a standard deviation of an instantaneous amplitude value and a standard deviation of the phase difference value between the consecutive symbols at the estimated symbol position of the received signal is set. Calculate the distance between the position on the two-dimensional plane represented by the coordinate value and the position of the pattern of each modulation signal, the received signal, the standard deviation of the instantaneous amplitude value at the estimated symbol position and the Modulation of a pattern located at the shortest distance from a position on a two-dimensional plane represented by a coordinate value that is a set of standard deviations of phase difference values between consecutive symbols An automatic modulation scheme identification receiver, comprising: an identification processing unit that outputs a scheme as an identification result; and a demodulation unit that demodulates a modulation signal based on the identification result.