JP2013143657A - Communication device and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a PAPR and further to control the degree of reduction of the PAPR in OFDM-system communication.SOLUTION: A modulation unit 11 generates a modulation signal from an input signal, and serial-parallel conversion unit 12 generates a sub-carrier modulation signal from the modulation signal. A code generation unit 14 generates a compression code by multiplying, and combining, a plurality of data sequences, each of which is aggregation of data comprising the same number of pieces as the number of sub-carriers, any data sequence having an autocorrelation characteristic, and in which a value of at least one element is different from one another, by an amplitude coefficient and a complex exponential function that are determined for each data sequence. An operation part 13 adds the compression code to the sub-carrier modulation signal. An IFFT unit 15 generates a baseband signal by applying inverse fast Fourier transformation to the sub-carrier modulation signal to which the compression code is added. A transmission unit 16 generates a transmission signal from the baseband signal and transmits it to another device via an antenna 10.

Description

  The present invention relates to a communication device and a communication method.

  In OFDM (Orthogonal Frequency-Division Multiplexing) communication, an input signal is subjected to subcarrier modulation, IFFT (Inverse Fast Fourier Transformation) is performed, and a baseband signal is generated. Therefore, when the number of subcarriers increases and the FFT (Fast Fourier Transformation) size increases, a baseband signal with a large peak is generated, and the PAPR (Peak-to-Average Power Ratio) ) Is high. As the PAPR increases, an amplifier having linearity in a wide range is required to transmit a signal without distortion. Therefore, techniques for reducing PAPR have been developed.

  In Patent Document 1, in order to reduce PAPR, the phase of the subcarrier modulation signal is controlled based on the optimum phase calculated by the sequential determination method before performing IFFT.

JP 2006-165781 A

  In OFDM communication, reducing PAPR is an issue. In Patent Document 1, it is necessary to perform iterative calculation processing in order to calculate the optimum phase for reducing the PAPR, and to control the phase for each subcarrier. Further, the technique disclosed in Patent Document 1 cannot control the degree of PAPR reduction.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce PAPR and control the degree of reduction of PAPR in OFDM communication.

In order to achieve the above object, a communication device according to the first aspect of the present invention provides:
A communication device that communicates with other devices by orthogonal frequency division multiplex communication wireless communication,
Modulation means for modulating an input signal by a predetermined modulation method, assigning frequency components to subcarriers orthogonal to each other, and generating a subcarrier modulation signal;
It is a data sequence that is a set of the same number of data as the number of subcarriers, and the autocorrelation value with the same data sequence that has not been shifted in data is the same as the data sequence that has undergone an arbitrary shift in data. An arbitrary data series having an autocorrelation characteristic that is higher than an autocorrelation value between, and a plurality of data series having different values of at least one element, an amplitude coefficient and a complex exponential function defined for each data series Calculating means for multiplying the subcarrier modulation signal by adding a compression code generated by combining a plurality of the data series subjected to the calculation;
IFFT means for generating a baseband signal by performing inverse fast Fourier transform on the calculation result of the calculation means;
Transmitting means for generating and transmitting a transmission signal from the baseband signal;
It is characterized by providing.

  Preferably, of the plurality of data series, a data series obtained by arbitrarily shifting data with respect to the arbitrary data series does not match any of the other data series.

  Preferably, a pseudo random noise sequence is used as the data sequence.

  Preferably, the maximum value of the amplitude of the element of the compression code is larger than the maximum value of the amplitude of the element of the subcarrier modulation signal.

The communication device according to the second aspect of the present invention is:
A communication device that communicates with other devices by orthogonal frequency division multiplex communication wireless communication,
Receiving means for receiving a transmission signal and generating a baseband signal;
FFT means for serially parallel converting the baseband signal and performing a fast Fourier transform to generate a parallel signal;
A data series that is a set of data of the same number as the number of subcarriers, and the autocorrelation value with the same data series that has not been shifted is between the data series that has undergone an arbitrary shift of data. An amplitude coefficient and a complex exponential function defined for each data series are assigned to a plurality of predetermined data series having an autocorrelation characteristic that is higher than the autocorrelation value and having a value of at least one element different from each other. Inverse calculation means for performing a multiplication operation, subtracting a compression code generated by combining the plurality of data series subjected to the calculation from the parallel signal, and generating a subcarrier modulation signal;
Demodulation means for demodulating the subcarrier modulation signal by a predetermined demodulation method;
It is characterized by providing.

  Preferably, of the plurality of data series, a data series obtained by arbitrarily shifting data with respect to the arbitrary data series does not match any of the other data series.

  Preferably, a pseudo random noise sequence is used as the data sequence.

  Preferably, the maximum value of the amplitude of the element of the compression code is larger than the maximum value of the amplitude of the element of the subcarrier modulation signal.

  Preferably, the receiving unit detects a synchronization position of the baseband signal by utilizing a correlation between data obtained by serial-parallel conversion of the baseband signal and the compression code, and detects the baseband signal. Extract the signal.

The communication method according to the third aspect of the present invention is:
A communication method performed by a communication device that communicates with other devices by wireless communication of an orthogonal frequency division multiplex communication method,
A modulation step of modulating an input signal with a predetermined modulation method, assigning frequency components to subcarriers orthogonal to each other, and generating a subcarrier modulation signal;
It is a data sequence that is a set of the same number of data as the number of subcarriers, and the autocorrelation value with the same data sequence that has not been shifted in data is the same as the data sequence that has undergone arbitrary shift of data An arbitrary data series having an autocorrelation characteristic that is higher than an autocorrelation value between, and a plurality of data series having different values of at least one element, an amplitude coefficient and a complex exponential function defined for each data series A calculation step of multiplying the subcarrier modulation signal with a compression code generated by combining the plurality of data series subjected to the calculation,
An IFFT step for generating a baseband signal by performing an inverse fast Fourier transform on a calculation result of the calculation step;
A transmission step of generating and transmitting a transmission signal from the baseband signal;
It is characterized by providing.

A communication method according to a fourth aspect of the present invention is:
A communication method performed by a communication device that communicates with other devices by wireless communication of an orthogonal frequency division multiplex communication method,
A reception step of receiving a transmission signal and generating a baseband signal;
An FFT step of serially parallel converting the baseband signal and performing a fast Fourier transform to generate a parallel signal;
A data series that is a set of data of the same number as the number of subcarriers, and the autocorrelation value with the same data series that has not been shifted is between the data series that has undergone an arbitrary shift of data. An amplitude coefficient and a complex exponential function defined for each data series are assigned to a plurality of predetermined data series having an autocorrelation characteristic that is higher than the autocorrelation value and having a value of at least one element different from each other. An inverse operation step of performing a multiplication operation, subtracting a compression code generated by combining the plurality of data series subjected to the operation from the parallel signal, and generating a subcarrier modulation signal;
A demodulation step for demodulating the subcarrier modulation signal by a predetermined demodulation method;
It is characterized by providing.

  According to the present invention, it is possible to reduce PAPR and further control the degree of PAPR reduction in OFDM communication.

It is a block diagram which shows the structural example of the communication apparatus which concerns on embodiment of this invention. It is a block diagram which shows the example of a different structure of the communication apparatus which concerns on embodiment. It is a figure which shows the structural example of the code generation part in embodiment. It is a figure which shows the principle which reduces PAPR using the communication apparatus which concerns on embodiment. It is a figure which shows the waveform of the signal used by simulation. It is a figure which shows the PAPR characteristic of the simulated baseband signal. It is a figure which shows the CCDF characteristic of PAPR of the simulated baseband signal. It is a figure which shows the result of the simulated correlation analysis.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent parts are denoted by the same reference numerals. In the following description, IFFT (Inverse Fast Fourier Transformation) is a concept including IFFT and IDFT (Inverse Discrete Fourier Transformation). Therefore, in the embodiment of the present invention, IDFT may be performed instead of IFFT. Similarly, FFT (Fast Fourier Transformation) is a concept including FFT and DFT (Discrete Fourier Transformation). When performing IDFT and DFT, the FFT size in the following description means the size of the DFT.

  FIG. 1 is a block diagram illustrating a configuration example of a communication device according to an embodiment of the present invention. The communication device 1 communicates with other devices by OFDM (Orthogonal Frequency-Division Multiplexing) wireless communication. The communication device 1 includes an antenna 10, a modulation unit 11, a serial-parallel conversion unit 12, a calculation unit 13, a code generation unit 14, an IFFT unit 15, a transmission unit 16, and a controller 20.

  The controller 20 includes a CPU (Central Processing Unit) 21, a RAM (Random Access Memory) 23, and a ROM (Read-Only Memory) 24. In order to avoid complication and to facilitate understanding, signal lines from the controller 20 to each part are omitted, but the controller 20 is connected to each part of the communication device 1 via an I / O (Input / Output) 22. The start and end of these processes and the control of the process contents are performed.

  In the RAM 23, for example, data for generating a transmission frame is stored. The ROM 24 stores a control program for the controller 20 to control the operation of the communication device 1. The controller 20 controls the communication device 1 based on the control program.

  FIG. 2 is a block diagram illustrating a different configuration example of the communication device according to the embodiment. In order to provide the above-described communication device 1 with a reception function, the communication device 1 illustrated in FIG. 2 further includes a demodulation unit 31, a parallel-serial conversion unit 32, an inverse operation unit 33, a code generation unit 34, an FFT unit 35, a reception unit 36, and A transmission / reception switching unit 37 is provided. A communication method performed by the communication device 1 using the communication device 1 shown in FIG. 2 having a transmission function and a reception function will be described below.

  The modulation unit 11 modulates the input signal using a predetermined modulation method, generates a modulation signal, and sends the modulated signal to the serial-parallel conversion unit 12. For example, QPSK (Quadrature Phase-Shift Keying) is used as the modulation method. The serial / parallel converter 12 performs serial / parallel conversion on the modulation signal to generate a parallel signal, assigns the frequency components to subcarriers orthogonal to each other, and generates a subcarrier modulation signal. Then, the subcarrier modulation signal is sent to the calculation unit 13.

  The code generation unit 14 is a data sequence that is a set of data of the same number as the number of subcarriers, and is an arbitrary data sequence having autocorrelation characteristics, and a plurality of data sequences having different values of at least one element prepare. Then, an operation of multiplying a plurality of data series by an amplitude coefficient and a complex exponential function determined for each data series is performed, and a plurality of data series subjected to the operation are synthesized to generate a compression code. The amplitude coefficient determined for each data series is a value other than zero. A data sequence having autocorrelation characteristics has a higher autocorrelation value with the same data sequence that has not been subjected to data shift than an autocorrelation value with a data sequence that has undergone arbitrary data shift It is a data series. A data series that has undergone an arbitrary shift of data differs in the value of at least one element from a data series that has not undergone a data shift.

  A plurality of different data series can be used as the plurality of data series. Multiple data series of different types means a data series in which data is arbitrarily shifted with respect to an arbitrary data series among the multiple data series and does not match any of the other data series To do. By using a plurality of different types of data series, the randomness of the compression code increases and the PAPR of the baseband signal can be reduced. Further, as will be described later, when symbol synchronization is performed on the receiving side, a positive peak appears only at the origin, so that synchronization processing is easy.

  For the same data series, a data series with an arbitrary data shift and a data series without a data shift are different data series. Therefore, a plurality of different data generated by shifting data of the same data series are generated. A data series may be used. In this case, when symbol synchronization is performed on the receiving side, a positive peak appears in a location other than the origin, but a different value is used. Compared to the case, the synchronization process becomes difficult. A plurality of different types of data series and a plurality of different data series generated by shifting data of the same data series may be used together.

  As the above data series, for example, a PN (Pseudorandom Noise) series can be used. A CAZAC (Constant Amplitude Zero Auto-Correlation) sequence can also be used. However, since the PN sequence has more types than the CAZAC sequence, the PN sequence is preferable. When the number of subcarriers is N, a plurality of different types of PN sequences are represented by the following equation (1). The subscript is a number for distinguishing each PN series, and the superscript indicates the number of elements of the PN series.

When each PN sequence is expressed as PN _k ^(N) , the compression code C is expressed by the following equation (2). In the following equation (2), A _k is an amplitude coefficient defined for each data series, and exp (jθ _k ) is a complex exponential function defined for each data series. j is an imaginary unit.

  FIG. 3 is a diagram illustrating a configuration example of the code generation unit in the embodiment. The code generation unit 14 includes a code generator 141, an amplifier 142, a phase rotator 143, and a synthesis unit 144. The code generator 141 generates, for example, a PN sequence as a plurality of different types of data sequences, and sends it to the amplifier 142. The amplifier 142 multiplies the data series by the amplitude coefficient determined for each data series, and sends the data series multiplied by the amplitude coefficient to the phase rotator 143. The phase rotator 143 rotates the phase by multiplying the transmitted data series by a complex exponential function determined for each data series. The phase rotator 143 sends the data series multiplied by the complex exponential function to the synthesis unit 144. The synthesizer 144 synthesizes the transmitted data series to generate a compressed code C.

  The code generation unit 14 sends the compression code C to the calculation unit 13. The calculation unit 13 adds the compression code C to the subcarrier modulation signal d and sends the calculation result d ′ obtained by adding the compression code to the IFFT unit 15 as expressed by the following equation (3).

  The IFFT unit 15 performs an IFFT on the calculation result d ′, generates a baseband signal, and sends the baseband signal to the transmission unit 16. The transmission unit 16 generates a transmission signal from the baseband signal, and transmits the transmission signal to other devices via the transmission / reception switching unit 37 and the antenna 10.

The principle of reducing PAPR (Peak-to-Average Power Ratio) using the communication device according to the embodiment will be described. FIG. 4 is a diagram illustrating the principle of reducing the PAPR using the communication device according to the embodiment. The horizontal axis represents frequency (unit: subcarrier interval f ₀ ), and the vertical axis represents amplitude. 4A shows the subcarrier modulation signal d, FIG. 4B shows the compression code C, and FIG. 4C shows the calculation result d ′ of the calculation unit 13. The numbers on the bar graph in FIG. 4 indicate the amplitude at each frequency.

  The PAPR of the signal generated by performing the IFFT in FIG. 4A is 4.3151 dB. The PAPR of the signal generated by performing the IFFT in FIG. 4B is 3.0103 dB. The PAPR of the signal generated by performing the IFFT in FIG. 4C is 3.0737 dB.

  That is, since the PAPR of the signal generated by performing IFFT of the PN sequence is lower than the PAPR of the baseband signal generated from the subcarrier modulation signal, the compression code generated using the PN sequence is added to the subcarrier modulation signal. Thus, it is possible to reduce the PAPR of the baseband signal.

  Processing on the receiving side will be described below. The receiving unit 36 receives the transmission signal via the antenna 10 and the transmission / reception switching unit 37, generates a baseband signal, and sends it to the FFT unit 35. The FFT unit 35 performs serial-parallel conversion on the baseband signal and performs FFT to generate a parallel signal. The FFT unit 35 sends the parallel signal to the inverse operation unit 33.

  The code generation unit 34 determines, for each data series, a plurality of predetermined data series in which the number of data is the same as the number of subcarriers and has autocorrelation characteristics and at least one element value is different. The calculation is performed by multiplying the amplitude coefficient and the complex exponential function, respectively, and a plurality of data series subjected to the calculation are combined to generate a compression code. The predetermined data series is the same data series as the data series used on the transmission side, and the amplitude coefficient and complex exponential function determined for each data series are the same as the amplitude coefficient and complex exponential function used on the transmission side. Note that the code generation unit 34 is configured to hold only the information about the compression code instead of the information about the plurality of data series, the amplitude coefficient, and the phase value of the complex exponential function used to generate the compression code on the transmission side. May be.

  The code generation unit 34 sends the compression code to the inverse operation unit 33. The inverse operation unit 33 subtracts the compression code C from the parallel signal r as represented by the following equation (4).

  Here, since the parallel signal r is the same as the calculation result d ′ of the calculation unit 13 on the transmission side, it can be seen from the above equation (3) that the calculation result r ′ matches the subcarrier modulation signal d. The inverse operation unit 33 sends the subcarrier modulation signal d to the parallel / serial conversion unit 32. The parallel / serial converter 32 performs parallel / serial conversion on the subcarrier modulation signal, generates a serial signal, and sends the serial signal to the demodulator 31. The demodulator 31 demodulates the serial signal using a predetermined demodulation method. For example, the demodulator 31 performs QPSK demodulation of the serial signal. Thus, the input signal modulated by the modulation unit 11 can be demodulated by the demodulation unit 31 and output.

  The receiving unit 36 may be configured to perform symbol synchronization. Since the transmission-side arithmetic unit 13 adds a compression code to the subcarrier modulation signal and the IFFT unit 15 generates a baseband signal based on the calculation result, data obtained by serial-parallel conversion of the compression code and the baseband signal There is a positive correlation with. Therefore, the receiving unit 36 performs a correlation analysis with the compression code, detects the synchronization position of the baseband signal based on whether a positive peak whose correlation value is equal to or greater than a predetermined value appears, and extracts the baseband signal. be able to.

  As described above, according to the communication device 1 according to the embodiment of the present invention, it is possible to reduce PAPR by adding a compression code to a subcarrier modulation signal in the OFDM communication system. As will be described later, it is possible to reduce PAPR and control the degree of reduction of PAPR.

(Concrete example)
Next, the effect of the invention according to the present embodiment will be described by simulation. Using a random signal as an input signal, a simulation was performed for generating the baseband signal and repeatedly calculating the PAPR for the related art and the invention according to the present embodiment. The PAPR characteristics of the prior art and the invention according to the present embodiment were compared using QPSK as the modulation method and 2048 as the FFT size. The prior art is a method for generating a baseband signal from a subcarrier modulation signal without adding the above-described calculation in the calculation unit 13.

For the invention according to the present embodiment, four different types of PN sequences, PN ₁ , PN ₂ , PN ₃ , and PN ₄ were used. The amplitude coefficients multiplied by each PN sequence are -0.025, 0.05, 1 and 2, respectively. The phase values of the complex exponential function multiplied by each PN sequence are 45 °, −90 °, 0 °, and 22.5 °, respectively.

FIG. 5 is a diagram illustrating a waveform of a signal used in the simulation. The horizontal axis represents frequency (unit: subcarrier interval f ₀ ), and the vertical axis represents amplitude, showing a waveform of a part of the signal used in the simulation. FIG. 5A shows a signal waveform of a compression code generated by multiplying the above-described four PN sequences by the above-described amplitude coefficient and complex exponential function and synthesizing the PN sequences. FIG. 5B is a signal waveform of the subcarrier modulation signal. FIG. 5C shows a signal waveform of a calculation result obtained by adding a compression code to the subcarrier modulation signal.

  FIG. 6 is a diagram illustrating PAPR characteristics of a simulated baseband signal. The horizontal axis is the number of calculations that is the number of times of simulation, and the vertical axis is PAPR (unit: dB). The maximum value of PAPR in the prior art is 11.4 dB, whereas the maximum value of PAPR in the present embodiment is 8.7 dB, and the maximum PAPR is reduced by 2.7 dB. In addition, the average value of PAPR in the prior art is 9.1 dB, whereas the average value of PAPR in the present embodiment is 6.7 dB, and the average value of PAPR is reduced by 2.4 dB.

  In addition, the PAPR CCDF (Complementary Cumulative Distribution Function), that is, the characteristics of the occurrence probability of PAPR in the present embodiment and the PAPR are compared. FIG. 7 is a diagram showing the PAPR CCDF characteristics of the simulated baseband signal. The horizontal axis is PAPR (unit: dB), and the vertical axis is PAPR CCDF. The graph with the thinner line shows the CCDF characteristic of the PAPR of the prior art, and the graph with the thicker line shows the CCDF characteristic of the PAPR of the invention according to the present embodiment. In the range shown in FIG. 7, the PAPR of the invention according to the present embodiment is reduced as compared with the prior art.

  Note that the PAPR value changes by changing the amplitude coefficient and the phase value of the complex exponential function used when generating the compression code. Therefore, according to the invention according to the present embodiment, it has been found that, in the OFDM communication system, PAPR can be reduced and the degree of PAPR reduction can be controlled.

FIG. 8 is a diagram showing the result of the simulated correlation analysis. The horizontal axis represents frequency (unit: subcarrier interval f ₀ ), and the vertical axis represents power indicating the presence or absence of correlation. The frequency is a value corrected so that the frequency value when the power reaches the peak value becomes zero. Using the same compression code as in the above simulation, a baseband signal was generated by adding a compression code generated using a different type of PN sequence to a subcarrier modulation signal generated from a certain input signal. On the receiving side, a simulation of correlation analysis was performed between the compressed code and data obtained by serial-parallel conversion of the baseband signal. As shown in FIG. 8, a positive peak appears. Therefore, in the present embodiment, it has been found that the synchronization position of the baseband signal can be detected using the correlation between the compression code and the data obtained by serial-parallel conversion of the baseband signal.

  The embodiment of the present invention is not limited to the above-described embodiment. The modulation method of the modulation unit 11 is not limited to QPSK, and PSK (Phase Shift Keying) other than QPSK, Quadrature Amplitude Modulation (QAM), or the like can be used. The order of the modulation unit 11 and the serial / parallel conversion unit 12 may be changed, the input signal may be serial / parallel converted and assigned to the subcarrier signal, and each data of the parallel signal may be modulated by a predetermined modulation method. In that case, the receiving side performs demodulation processing by changing the order of the demodulator 31 and the parallel-serial converter 32.

  Since the PAPR of the compression code is lower than the PAPR of the subcarrier modulation signal, it is possible to configure the PAPR so that the maximum amplitude of the compression code element is larger than the maximum amplitude of the subcarrier modulation signal element. Further reduction is possible. The IFFT unit 15 may be configured to perform IDFT instead of IFFT, and the FFT unit 35 may be configured to perform DFT instead of FFT.

DESCRIPTION OF SYMBOLS 1 Communication apparatus 10 Antenna 11 Modulation part 12 Serial / parallel conversion part 13 Calculation part 14, 34 Code generation part 15 IFFT part 16 Transmission part 20 Controller 21 CPU
22 I / O
23 RAM
24 ROM
Reference Signs List 31 Demodulator 32 Parallel-serial converter 33 Inverse calculator 35 FFT unit 36 Receiver 37 Transmission / reception switching unit 141 Code generator 142 Amplifier 143 Phase rotator 144 Synthesizer

Claims (11)

A communication device that communicates with other devices by orthogonal frequency division multiplex communication wireless communication,
Modulation means for modulating an input signal by a predetermined modulation method, assigning frequency components to subcarriers orthogonal to each other, and generating a subcarrier modulation signal;
It is a data sequence that is a set of the same number of data as the number of subcarriers, and the autocorrelation value with the same data sequence that has not been shifted in data is the same as the data sequence that has undergone an arbitrary shift in data. An arbitrary data series having an autocorrelation characteristic that is higher than an autocorrelation value between, and a plurality of data series having different values of at least one element, an amplitude coefficient and a complex exponential function defined for each data series Calculating means for multiplying the subcarrier modulation signal by adding a compression code generated by combining a plurality of the data series subjected to the calculation;
IFFT means for generating a baseband signal by performing inverse fast Fourier transform on the calculation result of the calculation means;
Transmitting means for generating and transmitting a transmission signal from the baseband signal;
A communication device comprising:   The data series obtained by performing an arbitrary shift of data with respect to an arbitrary data series among the plurality of data series does not match any of the other data series. Communication machine.   The communication apparatus according to claim 1, wherein a pseudo random noise sequence is used as the data sequence.   4. The communication device according to claim 1, wherein the maximum value of the amplitude of the element of the compression code is larger than the maximum value of the amplitude of the element of the subcarrier modulation signal. 5. A communication device that communicates with other devices by orthogonal frequency division multiplex communication wireless communication,
Receiving means for receiving a transmission signal and generating a baseband signal;
FFT means for serially parallel converting the baseband signal and performing a fast Fourier transform to generate a parallel signal;
A data series that is a set of data of the same number as the number of subcarriers, and the autocorrelation value with the same data series that has not been shifted is between the data series that has undergone an arbitrary shift of data. An amplitude coefficient and a complex exponential function defined for each data series are assigned to a plurality of predetermined data series having an autocorrelation characteristic that is higher than the autocorrelation value and having a value of at least one element different from each other. Inverse calculation means for performing a multiplication operation, subtracting a compression code generated by combining the plurality of data series subjected to the calculation from the parallel signal, and generating a subcarrier modulation signal;
Demodulation means for demodulating the subcarrier modulation signal by a predetermined demodulation method;
A communication device comprising:   6. The data series obtained by performing an arbitrary shift of data with respect to an arbitrary data series among the plurality of data series does not match any of the other data series. Communication machine.   7. The communication device according to claim 5, wherein a pseudo random noise sequence is used as the data sequence.   The communication apparatus according to any one of claims 5 to 7, wherein the maximum value of the amplitude of the element of the compression code is larger than the maximum value of the amplitude of the element of the subcarrier modulation signal.   The receiving means detects the synchronization position of the baseband signal and extracts the baseband signal by utilizing the correlation between the data obtained by serial-parallel conversion of the baseband signal and the compression code. The communication device according to any one of claims 5 to 8, wherein A communication method performed by a communication device that communicates with other devices by wireless communication of an orthogonal frequency division multiplex communication method,
A modulation step of modulating an input signal with a predetermined modulation method, assigning frequency components to subcarriers orthogonal to each other, and generating a subcarrier modulation signal;
It is a data sequence that is a set of the same number of data as the number of subcarriers, and the autocorrelation value with the same data sequence that has not been shifted in data is the same as the data sequence that has undergone an arbitrary shift in data. An arbitrary data series having an autocorrelation characteristic that is higher than an autocorrelation value between, and a plurality of data series having different values of at least one element, an amplitude coefficient and a complex exponential function defined for each data series A calculation step of multiplying the subcarrier modulation signal with a compression code generated by combining the plurality of data series subjected to the calculation,
An IFFT step for generating a baseband signal by performing an inverse fast Fourier transform on a calculation result of the calculation step;
A transmission step of generating and transmitting a transmission signal from the baseband signal;
A communication method comprising: A communication method performed by a communication device that communicates with other devices by wireless communication of an orthogonal frequency division multiplex communication method,
A reception step of receiving a transmission signal and generating a baseband signal;
An FFT step of serially parallel converting the baseband signal and performing a fast Fourier transform to generate a parallel signal;
A data series that is a set of data of the same number as the number of subcarriers, and the autocorrelation value with the same data series that has not been shifted is between the data series that has undergone an arbitrary shift of data. An amplitude coefficient and a complex exponential function defined for each data series are assigned to a plurality of predetermined data series having an autocorrelation characteristic that is higher than the autocorrelation value and having a value of at least one element different from each other. An inverse operation step of performing a multiplication operation, subtracting a compression code generated by combining the plurality of data series subjected to the operation from the parallel signal, and generating a subcarrier modulation signal;
A demodulation step for demodulating the subcarrier modulation signal by a predetermined demodulation method;
A communication method comprising:

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