JP2012175371A - Receiving method and receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect, and modulate, desired signal sequences from received signal sequences including desired signal sequences whose electric power level is minute, by making use of a probability resonance phenomenon.SOLUTION: A receiver comprises a plurality of composite signal sequence generation units which generate composite signal sequences based either desired signal sequences or interference signal sequences included in received signal sequences; a composition unit which combines the composite signal sequences, white Gauss signal sequences and the received signal sequences for each composite signal sequence generated by the composite signal sequence generation units; a plurality of nonlinear response units which respectively calculate response signal sequences indicating nonlinear responses to the plural signal sequences combined by the composition unit; and a response signal composition unit which generates composite response signal sequences which combine the response signal sequences calculated by the nonlinear response units.

Description

  The present invention relates to a receiving method and a receiving apparatus.

  When a weak signal is input to a nonlinear system in the presence of a specific level of noise, a stochastic resonance phenomenon is known in which the output probabilistically increases and reproduces the waveform of the weak signal (for example, see Non-Patent Document 1). . Major examples of nonlinear systems in which stochastic resonance occurs include a threshold type and a bistable type.

  FIG. 3 is a diagram showing an example of a threshold type nonlinear system. FIG. 4 is a diagram illustrating an example of a bistable nonlinearity. In FIG. 3, the horizontal axis indicates time, and the vertical axis indicates the amplitude of each signal. In FIG. 4, the horizontal axis indicates the position of the particle, and the vertical axis indicates the potential of the particle. As shown in FIG. 3, a simple example of a threshold type nonlinear system observes whether or not the amplitude obtained by combining the signal sequence S (t) and the noise W (t) exceeds a certain threshold Th. It is a system. Further, as shown in FIG. 4, a simple example of a bistable nonlinear system is a particle (position: x (t)) moving on a bistable potential U (x) given by the following equation (1). ) Is a system for observing whether or not a potential peak can be exceeded when an external force (signal sequence S (t) + noise W (t)) is applied.

  In either nonlinear system, when the signal sequence S (t) is weak, the observation point (threshold value or potential peak) cannot be exceeded. However, there are times when the noise can be exceeded by adding noise, and when a certain level of noise is added to the signal sequence S (t), the probability of exceeding the observation point represents the waveform of the input weak signal. This is a stochastic resonance phenomenon. If the noise level is too low or too high, the waveform of the weak signal cannot be expressed, and therefore there is an optimum noise level for the nonlinear system to be used.

  A method for amplifying a weak signal using the stochastic resonance phenomenon has been studied (for example, see Non-Patent Documents 2 and 3). FIG. 5 is a schematic diagram illustrating a process of amplifying a signal using the stochastic resonance phenomenon. As shown in FIG. 5, in the amplification process, white gauss signals W1 (t) to Wn (t) generated by the internal noise source are synthesized with the received received signal sequence R (t) to obtain a received signal sequence. Each signal sequence obtained by synthesizing R (t) and white Gaussian signals W1 (t) to Wn (t) is input to a nonlinear system, and a signal sequence output by the nonlinear system is synthesized, whereby a received signal sequence R (t ) Can be amplified without deterioration.

R. Benzi, A. Sutera, and A. Vulpiani, “The Mechanism of stochastic resonance,” J. Phys. A, vol.14, 1981, pp.453-457 J. Collins, C. Show, and T. Imhoff, “Stochastic Resonance without turning,” Nature, vol.376, pp.236-238, Jul. 1995 H. Ham, T. Matsuoka, and K. Taniguchi, “Sub-threshold Detection Using Noise Statistics for Communications Applications,” 15th IEEE International Conference on Electronics, Circuits and Systems 2008, pp.1167-1170, Aug. 2008

  However, a received signal sequence in which a high power level noise is synthesized with a desired signal sequence having a weak power level, or a received signal in which a noise having a large power level and an interference signal such as another signal are synthesized with a weak desired signal sequence. When it is desired to acquire and demodulate a desired signal sequence from the sequence, the amplification method using the stochastic resonance phenomenon amplifies the received signal sequence itself. For this reason, noise and interference signals are also amplified, and it may not be possible to detect and demodulate a desired signal sequence with a weak power level included in the received signal sequence.

  The present invention has been made in view of the above circumstances, and uses a stochastic resonance phenomenon to detect and demodulate a desired signal sequence from a received signal sequence including a desired signal sequence having a weak power level, and To provide a receiving apparatus.

  In order to solve the above problem, the present invention provides a combined signal sequence generation step of generating a plurality of combined signal sequences based on either a desired signal sequence or an interference signal sequence included in a received signal sequence, and the combined signal For each of a plurality of synthesized signal sequences generated in the sequence generating step, the synthesized signal sequence, the white Gaussian signal sequence, and the received signal sequence are synthesized in the first synthesizing step and the first synthesizing step. A response signal calculation step for calculating a response signal sequence indicating a non-linear response to the signal sequence for each of a plurality of signal sequences, and a combined response signal sequence obtained by combining the plurality of response signal sequences calculated in the response signal calculation step. And a second synthesizing step to be generated.

  Further, the present invention provides the signal detection step of detecting a desired signal sequence from the combined response signal sequence based on the statistical feature quantity of the combined response signal sequence generated in the second combining step in the invention described above. And changing the power level of the composite signal sequence, the power level of the white Gaussian signal sequence, and the response characteristics of the nonlinear system based on the power level of the desired signal sequence detected in the signal detection step. And a parameter control step of maximizing the signal level to signal power to noise (SN) ratio of the desired signal sequence or the power level.

  In the invention described above, the present invention is characterized in that the composite signal sequence generated in the composite signal sequence generation step is generated from a signal included in the desired signal sequence.

  In the invention described above, the present invention is characterized in that the combined signal sequence generated in the combined signal sequence generation step is generated from a signal included in the interference signal sequence.

  Further, the present invention is the above-described invention, wherein the combined signal sequence generated in the combined signal sequence generating step is an unmodulated signal having a carrier frequency of the desired signal sequence or a replica signal of the interference signal sequence. It is generated from a signal in which positive and negative are inverted.

  Further, the present invention provides a plurality of combined signal sequence generation units that generate a combined signal sequence based on either a desired signal sequence or an interference signal sequence included in a received signal sequence, and the plurality of combined signal sequence generation units For each generated composite signal sequence, a composite unit that combines the composite signal sequence, a white Gaussian signal sequence, and the received signal sequence, and a response indicating a response of a non-linear system to a plurality of signal sequences combined by the composite unit A receiving apparatus comprising: a plurality of nonlinear response units that respectively calculate signal sequences; and a response signal combining unit that generates a combined response signal sequence obtained by combining a plurality of response signal sequences calculated by the nonlinear response unit. is there.

  In addition, the present invention provides a signal detection unit that detects a desired signal sequence from the combined response signal sequence based on a statistical feature quantity of the combined response signal sequence generated by the response signal combining unit. Based on the power level of the desired signal sequence detected by the signal detector, the power level of the composite signal sequence, the power level of the white Gaussian signal sequence, and the response characteristic of the nonlinear system are changed and detected. And a parameter control unit that maximizes the SN ratio of the desired signal sequence or the power level.

  In the invention described above, the present invention is characterized in that the combined signal sequence generation unit generates the combined signal sequence from signals included in the desired signal sequence.

  In the invention described above, the present invention is characterized in that the combined signal sequence generation unit generates the combined signal sequence from signals included in the interference signal sequence.

  Further, the present invention is the above-described invention, wherein the synthesized signal sequence generation unit is based on an unmodulated signal of a carrier frequency of the desired signal sequence or a signal obtained by inverting the sign of the replica signal of the interference signal sequence. The synthesized signal sequence is generated.

According to the present invention, a synthesized signal sequence generated based on one of a desired signal sequence and an interference signal sequence included in a received signal sequence and a received signal sequence are synthesized, and then the desired signal is used using the stochastic resonance phenomenon. The series was emphasized.
When the synthesized signal sequence is generated based on the desired signal sequence, it is possible to generate a strong stochastic resonance with respect to the desired signal sequence included in the received signal sequence by synthesizing the synthesized signal sequence and the received signal sequence. Therefore, even when the received signal sequence includes an interference signal sequence such as noise with a large power level or other signals, the desired signal sequence can be detected and demodulated by enhancing the desired signal sequence.
In addition, when the composite signal sequence is generated based on the interference signal sequence, it is possible to suppress the stochastic resonance for the interference signal sequence included in the reception signal sequence by combining the composite signal sequence and the reception signal sequence. Even when the received signal sequence includes an interference signal sequence such as noise having a high power level or other signals, the desired signal sequence can be detected and demodulated by enhancing the desired signal sequence.

It is a schematic block diagram which shows the structure of the receiver 1 in this embodiment. It is a flowchart which shows the receiving method of the receiver 1 in the embodiment. It is a figure which shows an example of a threshold-type nonlinear system. It is a figure which shows an example of a bistable type nonlinear system. It is a figure which shows an example of the amplifier which amplifies a signal using a stochastic resonance phenomenon.

Hereinafter, a reception method and a reception apparatus according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic block diagram showing the configuration of the receiving device 1 in the present embodiment. As shown in the figure, the receiving apparatus 1 detects and demodulates a desired signal sequence having a weak power level included in a received signal sequence R (t) input from the outside using a stochastic resonance phenomenon. The receiving apparatus 1 includes n composite signal sequence generation units 101 (101-1 to 101-n), n addition units 102 (102-1 to 102-n), and n white Gaussian signal generation units 103 ( 103-1 to 103-n), n adders 104 (104-1 to 104-n), n nonlinear response units 105 (105-1 to 105-n), an average calculator 106, and a signal detector 107, a signal demodulator 108, and a parameter controller 109. Here, n is a natural number of 1 or more.

The combined signal sequence generation unit 101-1 generates a combined signal sequence Z1 (t) to be combined with the received signal sequence R (t) and outputs it to the adding unit 102-1. The combined signal sequence generation units 101-2 to 101-n generate combined signal sequences Z2 (t) to Zn (t) to be combined with the received signal sequence R (t), similar to the combined signal sequence generation unit 101-1. And output to the adders 102-2 to 102-n.
The adder 102-1 performs synthesis by adding the input received signal sequence R (t) and the synthesized signal sequence Z1 (t) generated by the synthesized signal sequence generator 101-1, and obtained by synthesis. The signal series is output to adder 104-1. The adders 102-2 to 102-n, like the adder 102-1, receive the received signal sequence R (t) and the synthesized signal sequence generated by the synthesized signal sequence generators 101-2 to 101-n. The combination of adding Z2 (t) to Zn (t) is performed, and the signal sequences obtained by the combination are output to the addition units 104-2 to 104-n, respectively.

The white Gaussian signal generation unit 103-1 generates a white Gaussian signal (white Gaussian noise signal) W < ^b > 1 (t) having an average value of 0 and a variance σ ² and outputs the generated signal to the adder 104-1. The white Gaussian signal generators 103-2 to 103-n generate white Gaussian signals W2 (t) to Wn (t) and adders 104-2 to 104-, similarly to the white Gaussian signal generator 103-1. output to n.
The addition unit 104-1 performs synthesis by adding the signal sequence synthesized by the addition unit 102-1 and the white Gaussian signal W1 (t) generated by the white Gaussian signal generation unit 103-1, and is obtained by synthesis. The signal series is output to the nonlinear response unit 105-1. Similar to the adder 104-1, the adders 104-2 to 104-n generate the signal series synthesized by the adders 102-2 to 102-n and the white Gaussian signal generators 103-2 to 103-n. The resultant white Gaussian signals W2 (t) to Wn (t) are combined, and a signal sequence obtained by the combination is output to the nonlinear response units 105-2 to 105-n.

  The adder 102-1 and the adder 104-1 constitute a synthesizer 111-1 that synthesizes the synthesized signal sequence Z1 (t) and the white Gaussian signal W1 (t) with the received signal sequence R (t). is doing. The adding units 102-2 to 102-n and the adding units 104-2 to 104-n are combined with the received signal sequence R (t) in the same manner as the adding units 102-1 and 104-1. Combining sections 111-2 to 111-n are configured to synthesize the signal series Z2 (t) to Zn (t) and the white Gaussian signals W2 (t) to Wn (t).

The non-linear response unit 105-1 outputs a response signal sequence for the signal sequence synthesized by the addition unit 104-1 based on a predetermined non-linear system. Similarly to the non-linear response unit 105-1, the non-linear response units 105-2 to 105-n are response signal sequences for the signal sequence synthesized by the addition units 104-2 to 104-n based on a predetermined non-linear system. Is output.
For example, the nonlinear response units 105-1 to 105-n output the response signal sequence in the threshold type nonlinear system shown in FIG. 3, or the response signal sequence in the bistable nonlinear system shown in FIG. Process to output.
As described above, the receiving apparatus 1 combines the received signal sequence R (t) with the combined signal sequence Zi (t) and the white Gaussian signal Wi (t) (i = 1, 2,..., N) and combines them. N signal processing units 110-1 to 110-n for outputting a non-linear response signal sequence to the signal sequence.

The average calculation unit 106 calculates an average signal sequence obtained by averaging the response signal sequences output from the n signal processing units 110-1 to 110-n at each time point. Specifically, the average calculation unit 106 generates a combined response signal sequence by combining the values of a plurality of response signal sequences that are continuously input using addition for each time point. Further, the average calculation unit 106 sequentially calculates an average value by dividing the value of the combined response signal sequence by the number (n) of the plurality of combined signal sequences, and averages the plurality of response signal sequences. Is generated.
The average calculation unit 106 calculates the expected value (or probability) of the output in the nonlinear system by averaging the response signal series output by each of the nonlinear response units 105-1 to 105-n at each time point. Become. This expected value ideally indicates the amplitude of the desired signal sequence.

The signal detection unit 107 calculates a statistical feature quantity of the average signal sequence output from the average calculation unit 106 and detects a desired signal sequence included in the reception signal sequence R (t). For example, the signal detection unit 107 calculates the average value of the power spectrum density distribution per unit time and the power level for each predetermined frequency band as the statistical feature amount. Alternatively, the signal detection unit 107 calculates a correlation value with a known signal sequence such as a preamble included in the desired signal. Then, the signal detection unit 107 estimates the center frequency, frequency band, and power level of the signal from the bias of the power spectrum density distribution, and detects the desired signal sequence.
The signal demodulator 108 detects a desired signal sequence included in the average signal sequence output by the average calculator 106, and outputs an output signal obtained by demodulating the detected desired signal sequence based on a predetermined modulation method of the desired signal. Output.

The parameter control unit 109 uses the power levels of the combined signal sequences Z1 (t) to Zn (t) generated by the combined signal sequence generating units 101-1 to 101-n based on the desired signal sequence detected by the signal detecting unit 107. Further, the power level of the white Gaussian signals W1 (t) to Wn (t) generated by the white Gaussian signal generators 103-1 to 103-n and the parameters of the nonlinear system in the nonlinear responders 105-1 to 105-n are controlled. Parameter control is performed to adjust the response signal sequence output by each of the nonlinear response units 105-1 to 105-n.
At this time, the parameter control unit 109 combines the composite signal sequences Z1 (t) to Zn (Zn) so as to maximize the SN (Signal to Noise) ratio of the desired signal sequence detected by the signal detection unit 107. The power level of t), the power levels of the white Gaussian signals W1 (t) to Wn (t), and the response characteristics of the nonlinear system are changed. The parameter control unit 109 may perform parameter control so that the power level of the desired signal sequence detected by the signal detection unit 107 is maximized.

For example, the parameter in the threshold type nonlinear system is a threshold value. In this case, the parameter control unit 109 lowers the threshold level when the noise floor is very low and no signal is detected in the power spectrum density distribution of the desired signal sequence, and when the noise floor is very high, The response level in the nonlinear system is controlled by increasing the threshold level. The parameters in the bistable nonlinear system shown in FIG. 4 are variables a and b that determine the bistable potential U (x) and the well depth ΔU in the bistable potential U (x). In this case, the parameter control unit 109 changes the values of the variables a and b to increase or decrease the depth ΔU (= a ² / 4b) to control the threshold level in the threshold type nonlinear system. Similarly, response characteristics in the nonlinear system are controlled.

FIG. 2 is a flowchart illustrating a reception method of the reception device 1 in the present embodiment.
In the receiving device 1, the received signal sequence R (t) input from the outside is input to each of the adders 102-1 to 102-n (step S1). That is, each of the adders 102-1 to 102-n receives the duplicated received signal sequence R (t).
The adders 102-1 to 102-n respectively receive the received signal sequence R (t) and the combined signal sequences Z1 (t) to Zn () generated by the combined signal sequence generators 101-1 to 101-n. t) is added (step S2), and the signal sequence obtained by the addition is output to the adders 104-1 to 104-n.

  Here, the synthesized signal sequences Z1 (t) to Zn (t) generated by the synthesized signal sequence generators 101-1 to 101-n are, for example, a signal sequence based on a desired signal sequence or a received signal sequence R (t ) Is a signal sequence based on the interference signal sequence included. Specifically, an unmodulated signal sequence (hereinafter referred to as a carrier signal) having the same frequency as the carrier frequency of the desired signal, or a signal sequence in which the amplitude of the interference signal (or replica signal of the interference signal) is inverted. Are combined signal sequences Z1 (t) to Zn (t). Note that in the received signal sequence R (t), which signal is used as the interference signal is determined depending on which signal sequence included in the received signal sequence R (t) is the desired signal sequence.

Subsequently, the adders 104-1 to 104-n have the average value 0 generated by the signal series synthesized by the adders 102-1 to 102-n and the white Gaussian signal generators 103-1 to 103-n. And the white Gaussian signals W1 (t) to Wn (t) with variance σ ² (step S3), and the combined signal series is input to the nonlinear response units 105-1 to 105-n (step S3). S4).
The average calculator 106 outputs an average signal sequence obtained by averaging the n response signal sequences output by the nonlinear response units 105-1 to 105-n at each time point (step S5).

The signal detection unit 107 detects a desired signal sequence from the average signal sequence output by the average calculation unit 106 (step S6). At this time, the signal detection unit 107 may calculate the power spectrum density distribution of the average signal sequence and detect the desired signal sequence using the calculated power spectrum density distribution. Further, the signal detection unit 107 may calculate a correlation value with a known signal sequence such as a preamble included in the desired signal, and detect the desired signal sequence using the correlation value. The signal demodulator 108 detects a desired signal sequence from the average signal sequence output by the average calculator 106 and demodulates the detected desired signal sequence (step S7).
Note that the signal detection unit 107 may determine whether or not the desired signal sequence has been correctly detected based on the demodulation result in the signal demodulation unit 108.

The parameter control unit 109 performs parameter control based on the desired signal sequence detected by the signal detection unit 107 (step S8), the combined signal sequence generation units 101-1 to 101-n, and the white Gaussian signal generation units 103-1 to 103-1. 103-n and the nonlinear response units 105-1 to 105-n are fed back to maximize the SN ratio or power level of the desired signal sequence.
Note that the parameter control unit 109 compares the result of simulation or actual measurement with the desired signal sequence detected by the signal detection unit 107, thereby determining a predetermined composite signal sequence Z1 (t) to Zn (t) and white color. You may make it select how to change the power level of the Gaussian signal W1 (t) -Wn (t), and the response characteristic of the nonlinear response part 105-1 -105-n.

As described above, the receiving apparatus 1 in the present embodiment includes the combined signal series Z1 (t) to Zn (t) and the white Gaussian signal W1 (t) in each of the n signal processing units 110-1 to 110-n. ˜Wn (t) and received signal sequence R (t) are combined. Further, the non-linear response units 105-1 to 105-n modeling the non-linear system output to the average calculation unit 106 a response signal sequence for the signal sequence obtained by the synthesis. Further, the signal demodulator 108 demodulates the desired signal sequence from the average signal sequence obtained by averaging the n response signal sequences output from the nonlinear response units 105-1 to 105-n. In addition, the parameter control unit 109 determines the combined signal sequence Z1 (t) to Zn (t) and the white Gaussian signal W1 (t) to Wn (t) according to the SN ratio or amplitude (power level) of the desired signal sequence. And the response characteristics of the non-linear response units 105-1 to 105-n are controlled.
Accordingly, the receiving apparatus 1 can perform enhancement (amplification) using a stochastic resonance phenomenon on a desired signal sequence having a weak power level included in the received signal sequence R (t). Detection and demodulation can be performed, and reception performance for a desired signal sequence can be improved.

In the present embodiment, the receiving apparatus 1 adds the combined signal series Z1 (t) to Zn (t), the white Gaussian signals W1 (t) to Wn (t), and the received signal series R (t). However, the present invention is not limited to this, and a signal sequence may be synthesized using multiplication.
In addition, after the received signal sequence R (t) and the synthesized signal sequences Z1 (t) to Zn (t) are synthesized in the receiving apparatus 1, the signal sequence obtained by the synthesis and the white Gaussian signals W1 (t) to Wn. The configuration for combining (t) has been described, but the signal sequence and the combined signal sequence obtained by combining the received signal sequence R (t) and the white Gaussian signals W1 (t) to Wn (t) are combined. Z1 (t) to Zn (t) may be synthesized.

  In the present embodiment, the average calculation unit 106 calculates the average signal sequence by averaging the plurality of response signal sequences output by the nonlinear response units 105-1 to 105-n at each time point. However, the added signal sequence may be output without being divided by the number (n) of the plurality of synthesized signal sequences.

  Hereinafter, specific examples of the present embodiment will be described.

  In the first embodiment, the combined signal sequence generation units 101-1 to 101-n output carrier signals of desired signal sequences to be detected and demodulated as combined signal sequences Z1 (t) to Zn (t). At this time, the carrier frequency of the carrier signal is known, the desired signal included in the received signal sequence R (t), and the combined signal sequence Z1 (t ) To Zn (t) are time-synchronized.

Specifically, the frequency band and timing are determined in advance between the transmission side and the reception side, or in the reception device 1 from information indicating the statistical feature quantity of the desired signal sequence obtained from the power spectrum density distribution. A carrier frequency of a desired signal sequence is detected, or time synchronization is performed using a synchronization signal such as a preamble. The detected carrier frequency or the like may be stored in a storage unit (not shown) provided in the receiving apparatus 1 so that the detection of the carrier frequency again is unnecessary. A case where BPSK (Binary Phase Shift Keying) is used as the modulation scheme of the desired signal sequence will be described.
Here, the statistical feature amount is a power spectrum density distribution per unit time, an average value of power levels for each predetermined frequency band, or the like.

  In a signal modulated using BPSK, one bit of transmission data is represented by one symbol, and the phase difference between a signal having a transmission data value of “0” and a signal having a transmission data value of “1” is π It is. That is, a symbol corresponding to a bit indicating “0” (hereinafter referred to as 0 symbol) and a symbol corresponding to a bit indicating “1” (hereinafter referred to as 1 symbol) when the phase difference between the carrier signal and the carrier signal is 0 (zero). And the phase difference from the carrier signal is π.

  In step S2 of the receiving method shown in FIG. 2, when a carrier signal having a phase difference of 0 with respect to 0 symbol is combined with the received signal sequence R (t) as a combined signal sequence, the signal of 0 symbol is strengthened and 1 symbol The signals will be weakened. That is, of the signals (desired signal sequence) included in the received signal sequence R (t), a signal that matches the phase of the carrier signal is amplified, and a signal whose phase is shifted by π is suppressed. Further, when a carrier signal whose phase is shifted by π is combined with the received signal sequence R (t) as a combined signal sequence, the signal of 1 symbol is amplified and the signal of 0 symbol is suppressed.

  As described above, since a difference in amplitude level occurs between the 0 symbol signal and the 1 symbol signal, the parameter control unit 109 has white so that stochastic resonance occurs only for the signal strengthened by the synthesis. Each symbol of the BPSK signal is emphasized by performing parameter control for changing the power level of the Gaussian signals W1 (t) to Wn (t).

  For example, the combined signal sequence generators 101-1 to 101-m (m = n / 2) are combined signal sequences Z1 () as a carrier signal having a phase difference of 0 (zero) from the 0 symbol of the desired signal that has been BPSK modulated. t) to Zm (t), and the combined signal sequence generators 101- (m + 1) to 101-n are combined as a carrier signal whose phase difference from the 0 symbol of the desired signal is π. Zn (t) is generated. Thereby, the receiving apparatus 1 can simultaneously emphasize the 0 symbol and the 1 symbol of the desired signal subjected to BPSK modulation using the stochastic resonance phenomenon. Therefore, since the desired signal sequence included in the received signal sequence R (t) has a weak power level and is modulated by BPSK, the desired signal sequence is detected and received from the received signal sequence R (t). Demodulation can be performed. When demodulating, the 0 symbol and 1 symbol may be simultaneously emphasized and demodulated as described above, and both symbols may be separately emphasized and demodulated, and then synthesized and arranged as a demodulated data series. Also good.

  Here, the case where BPSK is used as the modulation method has been described, but FSK (Frequency Shift Keying), non-binary PSK (Phase Shift Keying), QAM (Quadrature Amplitude Modulation). Modulation method such as quadrature phase amplitude modulation) may be used. In this case, the combined signal sequence generation units 101-1 to 101-n generate a combined signal sequence according to the modulation scheme used when generating the desired signal sequence, and the combining units 102-1 to 102-n combine them. At this time, each symbol of the desired signal sequence included in the received signal sequence R (t) is amplified or suppressed. Then, the desired signal is emphasized by stochastic resonance using the difference between the symbols.

  Next, in Example 2, the desired signal sequence included in the received signal sequence R (t) as the combined signal sequence Z1 (t) to Zn (t) generated by the combined signal sequence generation units 101-1 to 101-n. And a replica of another signal sequence having a high power level is generated. At this time, it is assumed that the carrier frequency of the carrier signal of the desired signal sequence and the carrier signal of the other signal sequence are known and time-synchronized as in the first embodiment. Here, the receiving apparatus 1 can demodulate the other signal sequence from the received signal sequence R (t), and generates a replica of the other signal sequence by modulating the demodulation result. Can be performed.

When the received signal sequence R (t) includes one other signal sequence, the combined signal sequence generation units 101-1 to 101-n cancel other signal sequences based on replicas of the other signal sequences. Alternatively, the composite signal series Z1 (t) to Zn (t) to be suppressed are generated.
Thereby, in step S2 of the reception method shown in FIG. 2, a signal sequence in which other signal sequences included in the reception signal sequence R (t) are suppressed is combined, and the combined signal sequence and the white Gaussian signal are combined. The signal sequence thus obtained is input to the non-linear response units 105-1 to 105-n. Since other signal sequences having a high power level are suppressed, it is possible to enhance (amplify) the desired signal sequence having a weak power level using the stochastic resonance phenomenon.

Here, the case where the accuracy of the replica with respect to the other signal sequences generated by the combined signal sequence generation units 101-1 to 101-n is high and the case where it is low will be described.
When the accuracy of the replica with respect to other signal series is high, that is, when the period, power level (amplitude), phase, etc. are accurately reproduced, the received signals are combined by the adders 102-1 to 102-n. Since other signal sequences can be canceled from the sequence R (t), the desired signal sequence can be detected and demodulated by using the stochastic resonance phenomenon for the desired signal sequence included in the received signal sequence R (t). it can.

On the other hand, when the accuracy of the replica with respect to other signal sequences is low, the signal sequences output from the adders 102-1 to 102-n include other signal sequences that are suppressed but have some power. Will be. However, in this case, the parameter control unit 109 compares the signal sequence output from the signal detection unit 107 with the replica so as to reduce the power level of other signal sequences included in the average signal sequence. The power levels of the combined signal sequences Z1 (t) to Zn (t) output from the sequence generators 101-1 to 101-n are changed.
As a result, stochastic resonance in other signal sequences can be prevented, and stochastic resonance can be generated in the desired signal sequence to emphasize the desired signal sequence and detect and demodulate the desired signal sequence. it can.

As described above, synthesized signal sequence generation sections 101-1 to 101-n generate replicas of signal sequences other than the desired signal sequence included in received signal sequence R (t), and receive signal sequence R (t) By canceling or suppressing a signal sequence other than the desired signal sequence included in the signal sequence, it is possible to emphasize (amplify) the desired signal sequence having a weak power level using the stochastic resonance phenomenon, and receive signal sequence R (t) Thus, a desired signal sequence can be detected and demodulated.
Further, when there are a plurality of signal sequences included in the received signal sequence R (t) other than the desired signal sequence, the combined signal sequence generation units 101-1 to 101-n generate replicas by combining the signal sequences, The desired signal sequence may be emphasized.
Further, in addition to the replica, the signal sequence based on the carrier signal of the desired signal sequence is included in the combined signal sequence Z1 (t) to Zn (t), thereby enhancing the desired signal sequence included in the received signal sequence R (t). However, a signal included in the received signal sequence R (t) other than the desired signal sequence may be canceled or suppressed.

  Note that a program for realizing the reception method in the reception apparatus 1 according to the present invention is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed to receive the program. Detection and demodulation of a desired signal sequence having a weak power level included in the signal may be performed. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer system” includes a WWW system having a homepage providing environment (or display environment). The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Further, the “computer-readable recording medium” refers to a volatile memory (RAM) in a computer system that becomes a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In addition, those holding programs for a certain period of time are also included.

  The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

  The response signal combining unit described in the present invention corresponds to the average calculating unit described in the embodiment.

DESCRIPTION OF SYMBOLS 1 ... Receiving device 101-1, 101-2, 101-n ... Synthetic signal sequence production | generation part 102-1, 102-2, 102-n ... Addition part 103-1, 103-2, 103-n ... White Gaussian signal Generation unit 104-1, 104-2, 104-n ... Addition unit 105-1, 105-2, 105-n ... Nonlinear response unit 106 ... Average calculation unit 107 ... Signal detection unit 108 ... Signal demodulation unit 109 ... Parameter control Units 110-1, 110-2, 110-n ... Signal processing units 111-1, 111-2, 111-n ... Synthesizer

Claims (10)

A combined signal sequence generating step for generating a plurality of combined signal sequences based on any of the desired signal sequence and the interference signal sequence included in the received signal sequence;
For each of a plurality of synthesized signal sequences generated in the synthesized signal sequence generating step, a first synthesizing step for synthesizing the synthesized signal sequence, a white Gaussian signal sequence, and the received signal sequence;
A response signal calculating step for calculating a response signal sequence indicating a response of a nonlinear system to the signal sequence for each of the plurality of signal sequences combined in the first combining step;
And a second combining step for generating a combined response signal sequence by combining the plurality of response signal sequences calculated in the response signal calculating step. A signal detection step of detecting a desired signal sequence from the combined response signal sequence based on a statistical feature quantity of the combined response signal sequence generated in the second combining step;
Based on the power level of the desired signal sequence detected in the signal detection step, the power level of the composite signal sequence, the power level of the white Gaussian signal sequence, and the response characteristic of the nonlinear system are changed and detected. The reception method according to claim 1, further comprising a parameter control step of maximizing an S / N ratio of the desired signal sequence or a power level. The reception method according to claim 1, wherein the combined signal sequence generated in the combined signal sequence generation step is generated from a signal included in the desired signal sequence. The reception method according to any one of claims 1 to 3, wherein the combined signal sequence generated in the combined signal sequence generation step is generated from a signal included in the interference signal sequence. The composite signal sequence generated in the composite signal sequence generation step is generated from an unmodulated signal having a carrier frequency of the desired signal sequence or a signal obtained by inverting the sign of the replica signal of the interference signal sequence. The reception method according to any one of claims 1 to 4. A plurality of combined signal sequence generation units for generating a combined signal sequence based on one of the desired signal sequence and the interference signal sequence included in the received signal sequence;
For each combined signal sequence generated by the plurality of combined signal sequence generating units, a combining unit that combines the combined signal sequence, a white Gaussian signal sequence, and the received signal sequence;
A plurality of nonlinear response units that respectively calculate response signal sequences indicating response of a nonlinear system to the plurality of signal sequences synthesized by the synthesis unit;
A receiving apparatus comprising: a response signal combining unit that generates a combined response signal sequence by combining a plurality of response signal sequences calculated by the nonlinear response unit. A signal detection unit for detecting a desired signal sequence from the combined response signal sequence based on a statistical feature quantity of the combined response signal sequence generated by the response signal combining unit;
Based on the power level of the desired signal sequence detected by the signal detector, the power level of the composite signal sequence, the power level of the white Gaussian signal sequence, and the response characteristic of the nonlinear system are changed to detect the desired signal The receiving apparatus according to claim 6, further comprising: a parameter control unit configured to maximize a signal sequence S / N ratio or a power level. The receiving apparatus according to claim 6, wherein the combined signal sequence generation unit generates the combined signal sequence from a signal included in the desired signal sequence. The receiving apparatus according to any one of claims 6 to 8, wherein the combined signal sequence generation unit generates the combined signal sequence from signals included in the interference signal sequence. The composite signal sequence generation unit generates the composite signal sequence from an unmodulated signal having a carrier frequency of the desired signal sequence or a signal obtained by inverting the sign of a replica signal of the interference signal sequence. The receiving device according to any one of claims 6 to 9.

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