JP5942768B2 - COMMUNICATION DEVICE AND COMMUNICATION METHOD - Google Patents

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 the orthogonal frequency division multiplexing communication apparatus of Patent Literature 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 the orthogonal frequency division multiplexing communication apparatus of Patent Document 1, it is necessary to perform iterative calculation processing to calculate the optimum phase for reducing the PAPR, and to control the phase for each subcarrier.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce PAPR and simplify processing for reducing 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 two-phase shift keying modulation method or a four-phase shift keying modulation method, assigning frequency components to subcarriers orthogonal to each other, and generating a subcarrier modulation signal;
The number of elements is the same as the number of elements of the subcarrier modulation signal, and a predetermined data sequence corresponding to the modulation method used by the modulation means is used, and each element of the subcarrier modulation signal is assigned to the element and the data sequence. Replacing with a predetermined complex number corresponding to a combination with an element at the same position as the element, and calculating means for generating post-computation data having the same real part and imaginary part absolute values ;
IFFT means for performing inverse fast Fourier transform on the post-computation data;
Transmitting means for generating a baseband signal by combining the calculation results of the IFFT means, generating a transmission signal based on the baseband signal, and transmitting it to another device;
Equipped with a,
The computing means is
The subcarrier modulation signal is separated into a real part modulation signal that is a real part and an imaginary part modulation signal that is an imaginary part, and the data series is divided into a real part data series that is a real part and an imaginary part data series that is an imaginary part. Decomposing means for decomposing,
Each element of the real part modulation signal, the imaginary part modulation signal, the real part data series, and the imaginary part data series is replaced with 0 or 1 based on whether or not the element is equal to or greater than a threshold value, and binary Binary replacement means for generating a real part modulation signal, a binary imaginary part modulation signal, a binary real part data series, and a binary imaginary part data series, respectively;
Real part XOR data having each element as an exclusive OR of each element of the binary real part modulation signal and an element in the same position as the element of the binary real part data series is generated, and the binary imaginary XOR operation means for generating imaginary part XOR data having an exclusive OR of each element of the partial modulation signal and an element at the same position as the element of the binary imaginary part data series,
Adjustment means for generating the post-computation data by subtracting a predetermined complex number from each element of data obtained by combining the real part XOR data as a real part and the imaginary part XOR data as an imaginary part, and multiplying by a predetermined amplitude coefficient When,
The equipped and wherein the Rukoto.

  Preferably, the calculation means uses four regions having a real axis and an imaginary axis on a complex plane as boundaries, and each element of the subcarrier modulation signal belongs to a point on the complex plane corresponding to the element. The post-computation data replaced with the predetermined complex number indicating the region, corresponding to a combination of the region and the region to which the point on the complex plane corresponding to the element at the same position as the element of the data series belongs Is generated.

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 predetermined receiving side data sequence having the same number of elements as the number of elements of the parallel signal is used, and each element of the parallel signal is combined with the element at the same position as the element of the receiving side data series Inverse operation means for generating post-inverse operation data in which the real part and the imaginary part have the same absolute value by replacing with a predetermined complex number corresponding to
Demodulating means for demodulating the post-inverse data by two-phase shift keying or four-phase shift keying,
Equipped with a,
The inverse calculation means includes
The parallel signal is separated into a real part parallel signal that is a real part and an imaginary part parallel signal that is an imaginary part, and the receiving side data series is a real side receiving side data series and a receiving side imaginary part that is an imaginary part Receiving side disassembling means for decomposing the data series;
Each element of the real part parallel signal, the imaginary part parallel signal, the reception side real part data series, and the reception side imaginary part data series is set to 0 or 1 based on whether or not the element is equal to or more than a threshold value. Receiving side binary replacement means for generating a binary real part parallel signal, a binary imaginary part parallel signal, a receiving side binary real part data series, and a receiving side binary imaginary part data series, respectively,
Receiving side real part XOR data having each element as an exclusive OR of each element of the binary real part parallel signal and an element at the same position as the element of the receiving side binary real part data series, Reception for generating receiving side imaginary part XOR data having each element as an exclusive OR of each element of the binary imaginary part parallel signal and an element at the same position as the element of the receiving side binary imaginary part data series Side XOR operation means;
The inverse real data is obtained by subtracting a predetermined complex number from each element of data obtained by combining the reception side real part XOR data as a real part and the reception side imaginary part XOR data as an imaginary part, and multiplying by a predetermined amplitude coefficient. Receiving side adjusting means for generating
The equipped and wherein the Rukoto.

  Preferably, the inverse calculation means uses four regions having a real axis and an imaginary axis on the complex plane as boundaries, and each element of the parallel signal belongs to the point on the complex plane corresponding to the element. The inverse operation is performed by replacing the predetermined complex number indicating the region corresponding to a combination of the region and the region to which the point on the complex plane corresponding to the element at the same position as the element of the receiving data series belongs. Generate post data.

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 by a two-phase shift keying modulation method or a four-phase shift keying modulation method, assigning frequency components to subcarriers orthogonal to each other, and generating a subcarrier modulation signal;
The number of elements is the same as the number of elements of the subcarrier modulation signal, and a predetermined data sequence corresponding to the modulation scheme used in the modulation step is used, and each element of the subcarrier modulation signal is assigned to the element and the data sequence. An operation step of generating post-computation data having the same absolute value of the real part and the imaginary part by replacing with a predetermined complex number corresponding to a combination with the element at the same position as the element;
IFFT step for performing inverse fast Fourier transform on the post-computation data;
A transmission step of generating a baseband signal by combining the operation results of the IFFT step, generating a transmission signal based on the baseband signal, and transmitting the transmission signal to another device;
Equipped with a,
The calculation step includes:
The subcarrier modulation signal is separated into a real part modulation signal that is a real part and an imaginary part modulation signal that is an imaginary part, and the data series is divided into a real part data series that is a real part and an imaginary part data series that is an imaginary part. A decomposition step to decompose;
Each element of the real part modulation signal, the imaginary part modulation signal, the real part data series, and the imaginary part data series is replaced with 0 or 1 based on whether or not the element is equal to or greater than a threshold value, and binary A binary replacement step for generating a real part modulation signal, a binary imaginary part modulation signal, a binary real part data series, and a binary imaginary part data series, respectively;
Real part XOR data having each element as an exclusive OR of each element of the binary real part modulation signal and an element in the same position as the element of the binary real part data series is generated, and the binary imaginary An XOR operation step of generating imaginary part XOR data having an exclusive OR of each element of the partial modulation signal and an element at the same position as the element of the binary imaginary part data series;
An adjustment step of subtracting a predetermined complex number from each element of data obtained by combining the real part XOR data as a real part and the imaginary part XOR data as an imaginary part, and multiplying by a predetermined amplitude coefficient to generate the post-computation data When,
The equipped and wherein the Rukoto.

  Preferably, in the calculation step, four regions having a real axis and an imaginary axis on a complex plane as boundaries are used, and each element of the subcarrier modulation signal belongs to a point on the complex plane corresponding to the element. The post-computation data replaced with the predetermined complex number indicating the region, corresponding to a combination of the region and the region to which the point on the complex plane corresponding to the element at the same position as the element of the data series belongs Is generated.

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 predetermined receiving side data sequence having the same number of elements as the number of elements of the parallel signal is used, and each element of the parallel signal is combined with the element at the same position as the element of the receiving side data series An inverse operation step for generating post-inverse data in which the absolute values of the real part and the imaginary part are the same , replacing with a predetermined complex number corresponding to
Demodulating step for demodulating the post-inverse data by a two-phase shift keying modulation method or a four-phase shift keying modulation method;
Equipped with a,
The inverse operation step includes
The parallel signal is separated into a real part parallel signal that is a real part and an imaginary part parallel signal that is an imaginary part, and the receiving side data series is a real side receiving side data series and a receiving side imaginary part that is an imaginary part A reception side decomposition step for decomposing the data series;
Each element of the real part parallel signal, the imaginary part parallel signal, the reception side real part data series, and the reception side imaginary part data series is set to 0 or 1 based on whether or not the element is equal to or more than a threshold value. A receiving side binary replacement step for generating a binary real part parallel signal, a binary imaginary part parallel signal, a receiving side binary real part data series, and a receiving side binary imaginary part data series, respectively,
Receiving side real part XOR data having each element as an exclusive OR of each element of the binary real part parallel signal and an element at the same position as the element of the receiving side binary real part data series, Reception for generating receiving side imaginary part XOR data having each element as an exclusive OR of each element of the binary imaginary part parallel signal and an element at the same position as the element of the receiving side binary imaginary part data series A side XOR operation step;
The inverse real data is obtained by subtracting a predetermined complex number from each element of data obtained by combining the reception side real part XOR data as a real part and the reception side imaginary part XOR data as an imaginary part, and multiplying by a predetermined amplitude coefficient. A receiver adjustment step that generates
The equipped and wherein the Rukoto.

  Preferably, in the inverse operation step, four regions having a real axis and an imaginary axis on a complex plane as boundaries are used, and each element of the parallel signal is assigned to the point on the complex plane corresponding to the element. The inverse operation is performed by replacing the predetermined complex number indicating the region corresponding to a combination of the region and the region to which the point on the complex plane corresponding to the element at the same position as the element of the receiving data series belongs. Generate post data.

  According to the present invention, it is possible to reduce the PAPR and simplify the process for reducing the PAPR in the 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 example of the modulation process which the modulation part which concerns on embodiment performs. It is a block diagram which shows the structural example of the calculating part which concerns on embodiment. It is a figure which shows the example of the arithmetic processing which the calculating part which concerns on embodiment performs. It is a flowchart which shows an example of the operation | movement of transmission control which the communication apparatus which concerns on embodiment performs. It is a block diagram which shows the structural example of the inverse calculating part which concerns on embodiment. It is a figure which shows the example of the reverse calculation process which the reverse calculation part which concerns on embodiment performs. It is a flowchart which shows an example of the operation | movement of reception control which the communication apparatus which concerns on embodiment performs. It is a figure which shows the CCDF characteristic of PAPR of the baseband signal in the communication apparatus which concerns on embodiment. It is a figure which shows the BER characteristic in the communication apparatus which concerns on embodiment. It is a figure which shows the characteristic of PAPR of the baseband signal in the communication apparatus which concerns on embodiment. It is a figure which shows the CCDF characteristic of PAPR of the baseband signal in the communication apparatus which concerns on embodiment. It is a figure which shows the BER characteristic in the communication apparatus which concerns on embodiment. It is a figure which shows the characteristic of PAPR of the baseband signal in the communication apparatus which concerns on embodiment. It is a figure which shows the comparison of the characteristic of PAPR of the baseband signal in the communication apparatus which concerns on embodiment.

  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 DFT size.

  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, an IFFT unit 14, a transmission unit 15, 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, an FFT unit 34, a reception unit 35, and a transmission / reception switching unit 36. Prepare. 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 by BPSK (Binary Phase-Shift Keying) or QPSK (Quadrature Phase-Shift Keying), generates a modulated signal, and performs serial-parallel conversion. Send to part 12. FIG. 3 is a diagram illustrating an example of modulation processing performed by the modulation unit according to the embodiment. FIG. 3 shows each element of the modulation signal on the complex plane, and the value in parentheses is the value of the input signal before modulation corresponding to each element of the modulation signal. The serial / parallel converter 12 performs serial / parallel conversion on the modulation signal and assigns the subcarriers whose frequency components are orthogonal to each other to generate a subcarrier modulation signal. Then, the subcarrier modulation signal is sent to the calculation unit 13. When the number of subcarriers is N, the subcarrier modulation signal d is expressed by the following equation (1).

  The calculation unit 13 uses a predetermined data sequence according to the modulation scheme used in the modulation unit 11 and has the same number of elements as the number of elements of the subcarrier modulation signal d, and each element of the subcarrier modulation signal d Substituted by a predetermined complex number corresponding to the combination of the element and the element at the same position as the element of the data series, post-computation data is generated. When the modulation unit 11 uses BPSK, the calculation unit 13 uses a predetermined data sequence having at least two types of values. When the modulation unit 11 uses QPSK, the calculation unit 13 includes at least four types of data. A predetermined data series having values is used.

  The calculation unit 13 uses, for example, four regions having a real axis and an imaginary axis on the complex plane as boundaries, and each element of the subcarrier modulation signal d is defined as a region to which a point on the complex plane corresponding to the element belongs. Substituted with a predetermined complex number corresponding to a combination with a region to which a point on the complex plane corresponding to an element at the same position as the element of the data series belongs, post-computation data is generated. For example, a region where the real part is 0 or more and the imaginary part is 0 or more is defined as a first region, a region where the real part is less than 0 and the imaginary part is 0 or more is defined as a second region, and the real part is An area where the imaginary part is less than 0 and the imaginary part is less than 0 is defined as a third area, and an area where the real part is 0 or more and the imaginary part is less than 0 is defined as a fourth area. The predetermined complex number is a complex number indicating the region, and is a complex number located in each of the regions and having the same absolute value of the real part and the same absolute value of the imaginary part. The calculation unit 13 uses, for example, a CAZAC (Constant Amplitude Zero Auto-Correlation) sequence as a data sequence. An example of the operation of the calculation unit 13 will be described below.

FIG. 4 is a block diagram illustrating a configuration example of the calculation unit according to the embodiment. The calculation unit 13 includes a decomposition unit 131, binary replacement units 132a and 132b, XOR units 133a and 133b, and an adjustment unit 134. The decomposition unit 131 decomposes the subcarrier modulation signal d sent from the serial-parallel conversion unit 12 into a real part modulation signal that is a real part and an imaginary part modulation signal that is an imaginary part. Each element of the subcarrier modulation signal d is expressed by the following equation (2). However, j is an imaginary unit. The decomposition unit 131 decomposes the subcarrier modulation signal d into a real part modulation signal that is a set of a _i and an imaginary part modulation signal that is a set of b _i .

The decomposition unit 131 decomposes a CAZAC sequence having the same number of elements as the number of elements of the subcarrier modulation signal d into a real part data series that is a real part and an imaginary part data series that is an imaginary part. The CAZAC sequence c is expressed by the following equation (3), and each element of the CAZAC sequence c is expressed by the following equation (4). The decomposition unit 131 decomposes the CAZAC sequence c into a real part data series that is a set of α _i and an imaginary part data series that is a set of β _i .

  The decomposition unit 131 sends the real part modulation signal and the real part data series to the binary substitution unit 132a, and sends the imaginary part modulation signal and the imaginary part data series to the binary substitution unit 132b.

  The binary replacement unit 132a replaces each element of the real part modulated signal and the real part data series with 0 or 1 based on whether or not the element is equal to or greater than the respective threshold value. Each real value data series is generated. The binary replacement unit 132a sends the binary real part modulated signal and the binary real part data series to the XOR unit 133a. For example, when each element of the real part modulation signal and the real part data series is less than 0, the binary replacement unit 132a replaces the element with 0, and when the element is 0 or more, the binary replacement unit 132a replaces the element with 0. The binary real part modulated signal and the binary real part data series are generated by replacing with 1.

  Similarly to the binary replacement unit 132a, the binary replacement unit 132b replaces each element of the imaginary part modulated signal and the imaginary part data series with 0 or 1 based on whether the element is equal to or greater than the respective threshold value. Then, a binary imaginary part modulated signal and a binary imaginary part data series are respectively generated. The binary replacement unit 132b sends the binary imaginary part modulation signal and the binary imaginary part data series to the XOR unit 133b.

  The threshold values used when performing the above-described calculation for each of the real part modulation signal, real part data series, imaginary part modulation signal, and imaginary part data series may be different from each other, but each element corresponds to a CAZAC series. When using a data series in which a point on the complex plane is located on the circumference centered on the origin of the complex plane, the respective threshold values used in the calculations for the real part data series and the imaginary part data series are set to 0. Is preferred.

The XOR unit 133a generates real part XOR data having each element as an exclusive OR of each element of the binary real part modulation signal and the element at the same position as the element of the binary real part data series. The part XOR data is sent to the adjustment unit 134. The real part XOR data g is expressed by the following equation (5). [Re (d)] _th in the following equation (5) represents a binary real part modulation signal that is the result of replacing each element of the real part modulation signal Re (d) with 0 or 1. Similarly, [Re (c)] _th represents a binary real part data series.

The XOR unit 133b generates imaginary part XOR data having an exclusive OR of each element of the binary imaginary part modulation signal and an element at the same position as the element of the binary imaginary part data series as an imaginary part. The part XOR data is sent to the adjustment unit 134. The imaginary part XOR data h is expressed by the following equation (6). [Im (d)] _th in the following equation (6) represents a binary imaginary part modulation signal that is the result of replacing each element of the imaginary part modulation signal Im (d) with 0 or 1. Similarly, [Im (c)] _th represents a binary imaginary part data series.

  The adjustment unit 134 subtracts a predetermined complex number from each element of the data obtained by combining the real part XOR data g as the real part and the imaginary part XOR data h as the imaginary part, and multiplies the data by the predetermined amplitude coefficient to obtain the calculated data. Generate and send post-computation data to the IFFT unit 14. The value of each element of the real part XOR data g and the value of each element of the imaginary part XOR data h are 0 or 1. Therefore, each element of data obtained by combining the real part XOR data g as the real part and the imaginary part XOR data h as the imaginary part is any one of 0, 1, 1 + j, and j.

  For example, the adjustment unit 134 subtracts (1 + j) / 2 from each element of the combined data, and multiplies the predetermined amplitude coefficient Amp. The post-calculation data k is expressed by the following equation (7). Each element of m in the following formula (7) is (1 + j) / 2. Each element of the post-computation data k generated by performing the computation as described above is the real part of each of the four regions having the real axis and the imaginary axis as boundaries, as in the modulation signal generated by the modulation unit 11. It is a complex number whose absolute value and the absolute value of the imaginary part are the same. Therefore, it is possible to perform transmission by performing a predetermined process before transmission as in the conventional case. The absolute value of each element of the modulation signal may be different from the absolute value of each element of the post-computation data k.

  FIG. 5 is a diagram illustrating an example of calculation processing performed by the calculation unit according to the embodiment. In order to facilitate understanding, only the operation on the real part modulation signal will be described. 5A is a real part modulated signal, FIG. 5B is a binary real part modulated signal, FIG. 5C is a real part data series, FIG. 5D is a binary real part data series, FIG. (E) represents the real part XOR data g, and FIG. 5 (f) represents the real part of the post-computation data k. As shown in FIG. 5A, the absolute value of each element of the modulation signal is Amp. The binary replacement unit 132a replaces each element of the real part modulation signal shown in FIG. 5A with 0 or 1 based on whether or not the element is equal to or greater than a threshold value, and the binary replacement unit 132a shown in FIG. A value real part modulation signal is generated. Also, the binary replacement unit 132a replaces each element of the real part data series shown in FIG. 5C with 0 or 1 based on whether or not the element is equal to or greater than a threshold value, as shown in FIG. 5D. A binary real part data series is generated.

  The XOR unit 133a includes, as elements, an exclusive OR of the binary real part modulation signal shown in FIG. 5B and the binary real part data series shown in FIG. 5D. Real part XOR data g shown in FIG. The adjustment unit 134 subtracts a predetermined complex number from each element of data obtained by combining the real part XOR data g as a real part and the imaginary part XOR data h as an imaginary part, and multiplies the data by a predetermined amplitude coefficient to obtain post-computation data k Is generated. The real part of the post-computation data k has the value shown in FIG.

  Table 1 shows the relationship between each element of the subcarrier modulation signal d and each element of the post-computation data k determined by the combination of the elements at the same positions as the elements of the data series. In Table 1, a value less than the threshold value 0 is represented by-, and a value greater than or equal to the threshold value 0 is represented by +. The processing of the calculation unit 13 is not limited to the above-described example. For example, the data in Table 1 is stored, and is unique based on the combination of each element of the subcarrier modulation signal d and the element at the same position as the element of the data series. The values specified in (1) may be used as the elements of post-computation data k. The relationship between the combination of each element of the subcarrier modulation signal d and the element at the same position as the element of the data series and the element of the post-computation data is not limited to Table 1. When the value of the element of the data series is different from a certain value that can be taken by the subcarrier modulation signal d, the region to which the point on the complex plane corresponding to the element of the corresponding post-computation data k belongs is different. You just have to decide.

  The IFFT unit 14 to which the post-computation data k is sent from the adjustment unit 134 performs an IFFT of the post-computation data k and sends the computation result to the transmission unit 15. The transmission unit 15 generates a baseband signal by combining the calculation results of the IFFT unit 14, generates a transmission signal from the baseband signal, and transmits the transmission signal to other devices via the transmission / reception switching unit 36 and the antenna 10. Send.

  FIG. 6 is a flowchart illustrating an example of a transmission control operation performed by the communication device according to the embodiment. The modulation unit 11 modulates the input signal with BPSK or QPSK to generate a modulation signal, and the serial-parallel conversion unit 12 performs serial-parallel conversion on the modulation signal and assigns the frequency components to subcarriers orthogonal to each other, and subcarrier modulation A signal is generated (step S110). The decomposition unit 131 decomposes the subcarrier modulation signal d into a real part modulation signal that is a real part and an imaginary part modulation signal that is an imaginary part, and a data series is a real part data series that is a real part and an imaginary part that is an imaginary part The data series is decomposed (step S120).

  The binary replacement unit 132a replaces each element of the real part modulated signal and the real part data series with 0 or 1 based on whether or not the element is equal to or greater than the respective threshold value. Each value real part data series is generated, and the binary replacement part 132b, like the binary replacement part 132a, determines whether each element of the imaginary part modulation signal and the imaginary part data series is equal to or greater than the respective threshold value. The binary imaginary part modulation signal and the binary imaginary part data series are respectively generated by replacing with 0 or 1 based on whether or not (step S130).

  The XOR unit 133a generates real part XOR data g having an exclusive OR of each element of the binary real part modulation signal and an element at the same position as the element of the binary real part data series, The XOR unit 133b generates imaginary part XOR data h having each element as an exclusive OR of each element of the binary imaginary part modulation signal and an element at the same position as the element of the binary imaginary part data series ( Step S140). The adjustment unit 134 subtracts a predetermined complex number from each element of data obtained by combining the real part XOR data g as a real part and the imaginary part XOR data h as an imaginary part, and multiplies the data by a predetermined amplitude coefficient to obtain post-computation data k Is generated (step S150).

  The IFFT unit 14 performs IFFT of the post-computation data k (step S160). The transmission unit 15 generates a baseband signal by combining the calculation results of the IFFT unit 14, generates a transmission signal from the baseband signal, and transmits the transmission signal to other devices via the transmission / reception switching unit 36 and the antenna 10. Transmit (step S170). When the transmission process in step S170 is completed, the process ends.

  Processing on the receiving side will be described below. The receiving unit 35 receives a transmission signal via the antenna 10 and the transmission / reception switching unit 36, generates a baseband signal, performs serial-parallel conversion, and sends it to the FFT unit 34. The FFT unit 34 performs an FFT on the baseband signal that has been serial-parallel converted to generate a parallel signal, and sends the parallel signal to the inverse operation unit 33.

  The inverse operation unit 33 uses a predetermined receiving side data sequence having the same number of elements as the number of elements of the parallel signal, and each element of the parallel signal is an element at the same position as the element of the receiving side data series. Is replaced with a predetermined complex number corresponding to the combination of and the data after reverse operation is generated. The reception-side data series is the same data series as that used on the transmission side. The predetermined complex number is a complex number corresponding to the modulation scheme used in the modulation unit 11 on the transmission side, and is a value that can be taken by the modulation signal generated by the modulation unit 11. It is assumed that information on the complex number and the data series is held in advance on the receiving side.

  The inverse operation unit 33 uses, for example, four regions with a real axis and an imaginary axis on the complex plane as boundaries, and each element of the parallel signal is divided into a region to which a point on the complex plane corresponding to the element belongs and a receiving side. The data after the reverse operation is generated by replacing with a predetermined complex number indicating the region corresponding to the combination with the region to which the point on the complex plane corresponding to the element at the same position as the element of the data series belongs. The four regions are the same as the four regions used in the transmission-side arithmetic unit 13, and the predetermined complex number is also the same as the predetermined complex number used in the transmission-side arithmetic unit 13. An example of the operation of the inverse operation unit 33 will be described below.

  FIG. 7 is a block diagram illustrating a configuration example of the inverse operation unit according to the embodiment. The inverse operation unit 33 includes an adjustment unit 331, XOR units 332 a and 332 b, binary replacement units 333 a and 333 b, and a decomposition unit 334.

  The decomposition unit 334 decomposes the parallel signal sent from the FFT unit 34 into a real part parallel signal that is a real part and an imaginary part parallel signal that is an imaginary part, and the CAZAC sequence c is a reception side real part data sequence that is a real part. And the imaginary part receiving side imaginary part data series. The decomposition unit 334 sends the real part parallel signal and the reception side real part data series to the binary substitution unit 333a, and sends the imaginary part parallel signal and the reception side imaginary part data series to the binary substitution unit 333b.

  The binary replacement unit 333a replaces each element of the real part parallel signal and the real part data series with 0 or 1 based on whether or not the element is equal to or greater than the respective threshold value, so that the binary real part parallel signal and the reception are received. Each side binary real part data series is generated. The binary replacement unit 333a sends the binary real part parallel signal and the reception-side binary real part data series to the XOR unit 332a. The threshold used for the generation of the reception side binary real part data series is the same as the threshold used for the generation of the binary real part data series in the binary substitution part 132a on the transmission side. It shall be held. For example, the binary replacement unit 333a replaces the element with 0 when each element of the real part parallel signal and the reception side real part data series is less than 0, and when the element is 0 or more, The element is replaced with 1 to generate a binary real part parallel signal and a receiving-side binary real part data series. The binary real part parallel signal matches the real part XOR data g generated by the XOR part 133a on the transmission side.

  The binary replacement unit 333b replaces each element of the imaginary part parallel signal and the reception side imaginary part data series with 0 or 1 based on whether or not the element is equal to or greater than the respective threshold value, and the binary imaginary part parallel signal And the receiving side binary imaginary part data series is respectively generated. The binary replacement unit 333b sends the binary imaginary part parallel signal and the receiving side binary imaginary part data series to the XOR unit 332b. The threshold value used for generating the reception-side binary imaginary part data series is the same as the threshold value used for generating the binary imaginary part data series in the transmission-side binary replacement part 132b. It shall be held. The binary imaginary part parallel signal matches the imaginary part XOR data h generated by the XOR part 133b on the transmission side.

  The threshold values used for generating the binary real part parallel signal and the binary imaginary part parallel signal are preferably set to 0 in order to prevent deterioration of BER (Bit Error Rate).

The XOR unit 332a receives the reception side real part XOR data having the exclusive OR of each element of the binary real part parallel signal and the element at the same position as the element of the reception side binary real part data series as each element. It is generated and sent to the adjustment unit 331. The reception side real part XOR data w is expressed by the following equation (8). [Re (v)] _th in the following equation (8) represents a binary real part parallel signal that is the result of replacing each element of the real part parallel signal Re (v) with 0 or 1. Similarly, [Re (c)] _th represents a receiving-side binary real part data series. When the equation is transformed by using the fact that the binary real part parallel signal [Re (v)] _th matches the real part XOR data g generated by the XOR part 133a on the transmission side, the reception side real part XOR data w becomes This coincides with the binary real part modulated signal [Re (d)] _th generated by the binary substitution unit 133a on the transmission side.

The XOR unit 332b receives the reception-side imaginary part XOR data having the exclusive OR of each element of the binary imaginary part parallel signal and the element in the same position as the element of the reception-side binary imaginary part data series as each element. It is generated and sent to the adjustment unit 331. The reception side imaginary part XOR data x is expressed by the following equation (9). [Im (v)] _th in the following equation (9) represents a binary imaginary part parallel signal that is the result of replacing each element of the imaginary part parallel signal Im (v) with 0 or 1. Similarly, [Im (c)] _th represents a receiving-side binary imaginary part data series. If the equation is transformed using the fact that the binary imaginary part parallel signal [Im (v)] _th matches the imaginary part XOR data h generated by the transmitting side XOR part 133b, the receiving side imaginary part XOR data x becomes This coincides with the binary imaginary part modulation signal [Im (d)] _th generated by the binary substitution unit 132b on the transmission side.

  The adjustment unit 331 subtracts a predetermined complex number from each element of the data obtained by combining the reception side real part XOR data w as a real part and the reception side imaginary part XOR data x as an imaginary part, and multiplies the predetermined amplitude coefficient. Data after reverse calculation is generated and sent to the parallel-serial converter 32. The value of each element of the reception-side real part XOR data w and the value of each element of the reception-side imaginary part XOR data x are 0 or 1. Accordingly, each element of data obtained by combining the reception side real part XOR data w as the real part and the reception side imaginary part XOR data x as the imaginary part is one of 0, 1, 1 + j, and j.

  For example, the adjustment unit 331 subtracts (1 + j) / 2 from each element of the combined data, and multiplies the predetermined amplitude coefficient Amp. The post-inverse data y is expressed by the following equation (10). Each element of m in the following formula (10) is (1 + j) / 2. The predetermined amplitude coefficient Amp is an absolute value of each element of the modulation signal generated by the modulation unit 11 on the transmission side. By performing the calculation as described above, the subcarrier modulation signal d can be restored.

  FIG. 8 is a diagram illustrating an example of an inverse operation process performed by the inverse operation unit according to the embodiment. In order to facilitate understanding, only the operation on the real part will be described. 8A is a real part parallel signal, FIG. 8B is a binary real part parallel signal, FIG. 8C is a reception side real part data series, and FIG. 8D is a reception side binary real part data. FIG. 8E shows the real part of the reception side real part XOR data w, and FIG. 8F shows the real part of the post-inverse data y. The binary replacement unit 333a replaces each element of the real part parallel signal shown in FIG. 8 (a) with 0 or 1 based on whether or not the element is equal to or greater than a threshold value. Generate value real part parallel signal. Also, the binary replacement unit 333a replaces each element of the reception-side real part data series shown in FIG. 8C with 0 or 1 based on whether or not the element is equal to or greater than the threshold value, and FIG. The receiving side binary real part data series shown in FIG.

  The XOR unit 332a includes, as elements, an exclusive OR of the binary real part parallel signal shown in FIG. 8B and the receiving-side binary real part data series shown in FIG. 8D. The receiving side real part XOR data w shown in e) is generated. The adjustment unit 331 subtracts a predetermined complex number from each element of the data obtained by combining the reception side real part XOR data w as a real part and the reception side imaginary part XOR data x as an imaginary part, and multiplies the predetermined amplitude coefficient. Data y after reverse operation is generated. The real part of the post-inverse data y is the value shown in FIG. The real part of the post-inverse data y coincides with the real part modulated signal shown in FIG.

  The processing of the inverse operation unit 33 is not limited to the above example, and the data in Table 1 is stored in the same manner as the operation unit 13 and the combination of each element of the parallel signal and the element at the same position as the element of the data series. A value uniquely specified based on the value may be used as each element of post-inverse data y. The post-computation data in Table 1 corresponds to a parallel signal, and the subcarrier modulation signal in Table 1 corresponds to post-inverse computation data y.

  The parallel / serial conversion unit 32 performs parallel / serial conversion on the data y after the inverse operation and sends the data y to the demodulation unit 31. The demodulator 31 demodulates the parallel-serial converted data using BPSK or QPSK, and restores the input signal.

  FIG. 9 is a flowchart illustrating an example of a reception control operation performed by the communication device according to the embodiment. The receiving unit 35 receives a transmission signal via the antenna 10 and the transmission / reception switching unit 36, generates a baseband signal, and performs serial-parallel conversion (step S210). The FFT unit 34 performs the FFT of the baseband signal that has been subjected to the serial-parallel conversion to generate a parallel signal (step S220).

  The decomposing unit 334 decomposes the parallel signal into a real part parallel signal that is a real part and an imaginary part parallel signal that is an imaginary part, and the reception side data series is a reception side real part data series that is a real part and reception that is an imaginary part. Decompose into side imaginary part data series (step S230). The binary replacement unit 333a replaces each element of the real part parallel signal and the reception side real part data series with 0 or 1 based on whether or not the element is equal to or greater than the respective threshold value, thereby obtaining a binary real part parallel signal. And the reception side binary real part data series, respectively, and the binary replacement unit 333b determines whether each element of the imaginary part parallel signal and the reception side imaginary part data series is equal to or more than a threshold value. Based on 0 or 1, the binary imaginary part parallel signal and the receiving side binary imaginary part data series are respectively generated (step S240).

  The XOR unit 332a receives the reception side real part XOR data having the exclusive OR of each element of the binary real part parallel signal and the element at the same position as the element of the reception side binary real part data series as each element. The XOR unit 332b generates a receiving-side imaginary part having an exclusive OR of each element of the binary imaginary part parallel signal and the element at the same position as the element of the receiving-side binary imaginary part data series. XOR data is generated (step S250).

  The adjustment unit 331 subtracts a predetermined complex number from each element of the data obtained by combining the reception side real part XOR data w as a real part and the reception side imaginary part XOR data x as an imaginary part, and multiplies the predetermined amplitude coefficient. Data y after reverse calculation is generated (step S260). The parallel / serial conversion unit 32 performs parallel / serial conversion on the data y after the inverse operation and sends the data y to the demodulation unit 31. The demodulator 31 demodulates the parallel-serial converted data using BPSK or QPSK, and restores the input signal (step S270). When the demodulation process in step S270 is completed, the process ends.

  As described above, according to communication apparatus 1 according to the embodiment of the present invention, baseband based on post-computation data k generated by performing computation using a data sequence on subcarrier modulation signal d in the OFDM communication scheme. By generating the signal, it is possible to reduce the 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 modulation method is QPSK, the FFT size is 2048, and the PAPR CCDF (Complementary Cumulative Distribution Function) of the invention according to the present embodiment, that is, the characteristics of PAPR occurrence probability are compared. The prior art is a method of generating a baseband signal by performing IFFT of the subcarrier modulation signal d without performing the above-described calculation.

  FIG. 10 is a diagram illustrating the PAPR CCDF characteristics of the baseband signal in the communication device according to the embodiment. The horizontal axis is PAPR (unit: dB), and the vertical axis is PAPR CCDF. It is a thin line graph of CCDF characteristics of PAPR of the prior art. The PAPR of the invention according to the present embodiment is slightly reduced as compared with the prior art.

  The simulation was similarly performed for BER. FIG. 11 is a diagram illustrating BER characteristics in the communication device according to the embodiment. The horizontal axis represents Eb / No (Energy per Bit to NOise power spectral density ratio), and the vertical axis represents BER. The unit of Eb / No is dB. The BER of the prior art is a graph in which plot points are represented by squares, and the BER of the invention according to the present embodiment is a graph in which plot points are represented by triangles. In the range shown in FIG. 11, it can be seen that the BER of the prior art and the BER of the invention according to the present embodiment are substantially the same.

  FIG. 12 is a diagram illustrating PAPR characteristics of a baseband signal in the communication device according to the embodiment. The horizontal axis represents the number of elements having a value of 1 in the input signal, and the vertical axis represents PAPR (unit: dB). With respect to the prior art, when the same signal in which the phase of each element of the subcarrier modulation signal d has the same value is used as the input signal, the PAPR of the baseband signal becomes high. The PAPR when the elements of the input signal are all 0 is 33.1 dB. In order from the beginning, 0 was changed to 1, and the number of 1 was increased, and the same simulation was performed for the PAPR of the baseband signal.

  The PAPR of the prior art is a thin solid line graph, and the PAPR of the invention according to the present embodiment is a thick solid line graph, and the process of calculating the exclusive OR in the invention according to the present embodiment is calculated as a logical product. The PAPR when the process is changed to the process to be performed is a dotted line graph, and the PAPR when the process of calculating the exclusive OR in the invention according to the present embodiment is changed to the process of calculating the logical sum is a dashed line graph. is there. It can be seen that the PAPR can be reduced by using the communication device 1 according to the present embodiment for the same signal in which the phase of each element of the subcarrier modulation signal d has the same value.

  Next, a simulation was performed in the same manner with the modulation method set to BPSK and the FFT size set to 2048. In the calculation unit 13, when the real part XOR data g generated by performing a predetermined calculation on the real part modulation signal is used as the post-computation data k (hereinafter referred to as BPSK1), the real part modulation signal and the values of all elements Based on the imaginary part modulation signal having a value of 0, a simulation was performed for each case where post-computation data k generated by performing a predetermined computation as in the case of QPSK (hereinafter referred to as BPSK2).

  In the prior art, each point of the post-computation data k generated by performing the above computation on the points on the complex plane corresponding to each element of the subcarrier modulation signal d in the case of using BPSK and the subcarrier modulation signal d in the case of BPSK1 The point on the complex plane corresponding to the element is located at one of two points on the real axis of the complex plane. On the other hand, in the case of BPSK2, a point on the complex plane corresponding to each element of post-computation data k generated by performing the above computation on the subcarrier modulation signal d is bounded by the real axis and the imaginary axis of the complex plane. The absolute value of the real part and the absolute value of the imaginary part in each of the four regions are located at any one of the four points.

  FIG. 13 is a diagram illustrating the CCDF characteristics of the PAPR of the baseband signal in the communication device according to the embodiment. The horizontal axis is PAPR, and the vertical axis is the PAPR CCDF. 13A shows the case of BPSK1, and FIG. 13B shows the case of BPSK2. In the case of BPSK1, the PAPR of the invention according to the present embodiment is almost the same as that of the prior art. In the case of BPSK2, the PAPR of the invention according to the present embodiment has a CCDF value lower than that of the prior art in the range where the PAPR is 10 dB or more, and the PAPR is reduced.

  The simulation was similarly performed for BER. FIG. 14 is a diagram illustrating BER characteristics in the communication device according to the embodiment. The horizontal axis is Eb / No, and the vertical axis is BER. 14A shows the case of BPSK1, and FIG. 14B shows the case of BPSK2. The BER of the prior art is a graph in which plot points are represented by squares, and the BER of the invention according to the present embodiment is a graph in which plot points are represented by triangles in both cases of BPSK1 and BPSK2. In the range shown in FIG. 14, it can be seen that the BER of the prior art and the BER of the invention according to the present embodiment are substantially the same.

  FIG. 15 is a diagram illustrating a PAPR characteristic of a baseband signal in the communication device according to the embodiment. 15A shows the case of BPSK1, and FIG. 15B shows the case of BPSK2. The way of viewing the figure is the same as in FIG. It can be seen that in both cases of BPSK1 and BPSK2, the PAPR can be reduced by using the communication device 1 according to the present embodiment for the same signal.

  FIG. 16 is a diagram illustrating a comparison of PAPR characteristics of baseband signals in the communication device according to the embodiment. The PAPR characteristics of the baseband signal in the communication apparatus according to the present embodiment were compared between the case of BPSK1 shown in FIG. 15 (a) and the case of BPSK2 shown in FIG. 15 (b). In the case of BPSK1, the PAPR is a thin solid line graph, and in the case of BPSK2, the PAPR is a thick solid line graph. The PAPR in the case of BPSK1 is at a lower level than that in the case of BPSK2. On the other hand, the PAPR in the case of BPSK2 when the number of elements having a value of 1 in the input signal is in the range of 50 or less or in the range of 1900 or more, that is, when the input signal is the same signal or a signal close to the same signal. Is lower than that of BPSK1.

  From the above simulation, it is found that in this embodiment, the PAPR can be reduced by generating the baseband signal based on the post-computation data k generated by performing computation using the data series on the subcarrier modulation signal d. It was.

  The embodiment of the present invention is not limited to the above-described embodiment. The data series is not limited to the CAZAC series, and data such that the difference in the number of points corresponding to each element of the data series belonging to the four regions with the real and imaginary axes of the complex plane as a boundary is within a predetermined range. Any series may be used. The IFFT unit 14 may be configured to perform IDFT instead of IFFT, and the FFT unit 34 may be configured to perform DFT instead of FFT.

1 communication equipment
10 Antenna
11 Modulator
12 Series-parallel converter
13 Calculation unit
14 IFFT section
15 Transmitter
20 controller
21 CPU
22 I / O
23 RAM
24 ROM
31 Demodulator
32 Parallel to serial converter
33 Inverse operation part
34 FFT section
35 Receiver
36 Transmission / reception switching unit
131 Decomposition unit 132a, 132b Binary replacement unit 133a, 133b XOR unit
134 Adjustment unit
331 Adjustment unit 332a, 332b XOR unit 333a, 333b Binary replacement unit
334 Disassembly part

Claims (8)

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 two-phase shift keying modulation method or a four-phase shift keying modulation method, assigning frequency components to subcarriers orthogonal to each other, and generating a subcarrier modulation signal;
The number of elements is the same as the number of elements of the subcarrier modulation signal, and a predetermined data sequence corresponding to the modulation method used by the modulation means is used, and each element of the subcarrier modulation signal is assigned to the element and the data sequence. Replacing with a predetermined complex number corresponding to a combination with an element at the same position as the element, and calculating means for generating post-computation data having the same real part and imaginary part absolute values ;
IFFT means for performing inverse fast Fourier transform on the post-computation data;
Transmitting means for generating a baseband signal by combining the calculation results of the IFFT means, generating a transmission signal based on the baseband signal, and transmitting it to another device;
Equipped with a,
The computing means is
The subcarrier modulation signal is separated into a real part modulation signal that is a real part and an imaginary part modulation signal that is an imaginary part, and the data series is divided into a real part data series that is a real part and an imaginary part data series that is an imaginary part. Decomposing means for decomposing,
Each element of the real part modulation signal, the imaginary part modulation signal, the real part data series, and the imaginary part data series is replaced with 0 or 1 based on whether or not the element is equal to or greater than a threshold value, and binary Binary replacement means for generating a real part modulation signal, a binary imaginary part modulation signal, a binary real part data series, and a binary imaginary part data series, respectively;
Real part XOR data having each element as an exclusive OR of each element of the binary real part modulation signal and an element in the same position as the element of the binary real part data series is generated, and the binary imaginary XOR operation means for generating imaginary part XOR data having an exclusive OR of each element of the partial modulation signal and an element at the same position as the element of the binary imaginary part data series,
Adjustment means for generating the post-computation data by subtracting a predetermined complex number from each element of data obtained by combining the real part XOR data as a real part and the imaginary part XOR data as an imaginary part, and multiplying by a predetermined amplitude coefficient When,
Communicator, wherein Rukoto equipped with.   The arithmetic means uses four regions having a real axis and an imaginary axis on the complex plane as boundaries, and each element of the subcarrier modulation signal is assigned to the region to which the point on the complex plane corresponding to the element belongs. The post-computation data is generated by replacing the predetermined complex number indicating the region corresponding to a combination with the region to which the point on the complex plane corresponding to the element at the same position as the element of the data series belongs The communication device according to claim 1. 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 predetermined receiving side data sequence having the same number of elements as the number of elements of the parallel signal is used, and each element of the parallel signal is combined with the element at the same position as the element of the receiving side data series Inverse operation means for generating post-inverse operation data in which the real part and the imaginary part have the same absolute value by replacing with a predetermined complex number corresponding to
Demodulating means for demodulating the post-inverse data by two-phase shift keying or four-phase shift keying,
Equipped with a,
The inverse calculation means includes
The parallel signal is separated into a real part parallel signal that is a real part and an imaginary part parallel signal that is an imaginary part, and the receiving side data series is a real side receiving side data series and a receiving side imaginary part that is an imaginary part Receiving side disassembling means for decomposing the data series;
Each element of the real part parallel signal, the imaginary part parallel signal, the reception side real part data series, and the reception side imaginary part data series is set to 0 or 1 based on whether or not the element is equal to or more than a threshold value. Receiving side binary replacement means for generating a binary real part parallel signal, a binary imaginary part parallel signal, a receiving side binary real part data series, and a receiving side binary imaginary part data series, respectively,
Receiving side real part XOR data having each element as an exclusive OR of each element of the binary real part parallel signal and an element at the same position as the element of the receiving side binary real part data series, Reception for generating receiving side imaginary part XOR data having each element as an exclusive OR of each element of the binary imaginary part parallel signal and an element at the same position as the element of the receiving side binary imaginary part data series Side XOR operation means;
The inverse real data is obtained by subtracting a predetermined complex number from each element of data obtained by combining the reception side real part XOR data as a real part and the reception side imaginary part XOR data as an imaginary part, and multiplying by a predetermined amplitude coefficient. Receiving side adjusting means for generating
Communicator, wherein Rukoto equipped with. The inverse operation means uses four regions having a real axis and an imaginary axis on a complex plane as boundaries, and each element of the parallel signal is assigned to the region to which the point on the complex plane corresponding to the element belongs and The data after the inverse operation is replaced with the predetermined complex number indicating the region corresponding to a combination with the region to which the point on the complex plane corresponding to the element at the same position as the element of the receiving data series belongs. The communication device according to claim 3 , wherein the communication device is generated. 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 by a two-phase shift keying modulation method or a four-phase shift keying modulation method, assigning frequency components to subcarriers orthogonal to each other, and generating a subcarrier modulation signal;
The number of elements is the same as the number of elements of the subcarrier modulation signal, and a predetermined data sequence corresponding to the modulation scheme used in the modulation step is used, and each element of the subcarrier modulation signal is assigned to the element and the data sequence. An operation step of generating post-computation data having the same absolute value of the real part and the imaginary part by replacing with a predetermined complex number corresponding to a combination with the element at the same position as the element;
IFFT step for performing inverse fast Fourier transform on the post-computation data;
A transmission step of generating a baseband signal by combining the operation results of the IFFT step, generating a transmission signal based on the baseband signal, and transmitting the transmission signal to another device;
Equipped with a,
The calculation step includes:
The subcarrier modulation signal is separated into a real part modulation signal that is a real part and an imaginary part modulation signal that is an imaginary part, and the data series is divided into a real part data series that is a real part and an imaginary part data series that is an imaginary part. A decomposition step to decompose;
Each element of the real part modulation signal, the imaginary part modulation signal, the real part data series, and the imaginary part data series is replaced with 0 or 1 based on whether or not the element is equal to or greater than a threshold value, and binary A binary replacement step for generating a real part modulation signal, a binary imaginary part modulation signal, a binary real part data series, and a binary imaginary part data series, respectively;
Real part XOR data having each element as an exclusive OR of each element of the binary real part modulation signal and an element in the same position as the element of the binary real part data series is generated, and the binary imaginary An XOR operation step of generating imaginary part XOR data having an exclusive OR of each element of the partial modulation signal and an element at the same position as the element of the binary imaginary part data series;
An adjustment step of subtracting a predetermined complex number from each element of data obtained by combining the real part XOR data as a real part and the imaginary part XOR data as an imaginary part, and multiplying by a predetermined amplitude coefficient to generate the post-computation data When,
Communication method comprising Rukoto equipped with. In the calculation step, four regions having a real axis and an imaginary axis on the complex plane as boundaries are used, and each element of the subcarrier modulation signal is assigned to the region to which the point on the complex plane corresponding to the element belongs. The post-computation data is generated by replacing the predetermined complex number indicating the region corresponding to a combination with the region to which the point on the complex plane corresponding to the element at the same position as the element of the data series belongs The communication method according to claim 5 . 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 predetermined receiving side data sequence having the same number of elements as the number of elements of the parallel signal is used, and each element of the parallel signal is combined with the element at the same position as the element of the receiving side data series An inverse operation step for generating post-inverse data in which the absolute values of the real part and the imaginary part are the same , replacing with a predetermined complex number corresponding to
Demodulating step for demodulating the post-inverse data by a two-phase shift keying modulation method or a four-phase shift keying modulation method;
Equipped with a,
The inverse operation step includes
The parallel signal is separated into a real part parallel signal that is a real part and an imaginary part parallel signal that is an imaginary part, and the receiving side data series is a real side receiving side data series and a receiving side imaginary part that is an imaginary part A reception side decomposition step for decomposing the data series;
Each element of the real part parallel signal, the imaginary part parallel signal, the reception side real part data series, and the reception side imaginary part data series is set to 0 or 1 based on whether or not the element is equal to or more than a threshold value. A receiving side binary replacement step for generating a binary real part parallel signal, a binary imaginary part parallel signal, a receiving side binary real part data series, and a receiving side binary imaginary part data series, respectively,
Receiving side real part XOR data having each element as an exclusive OR of each element of the binary real part parallel signal and an element at the same position as the element of the receiving side binary real part data series, Reception for generating receiving side imaginary part XOR data having each element as an exclusive OR of each element of the binary imaginary part parallel signal and an element at the same position as the element of the receiving side binary imaginary part data series A side XOR operation step;
The inverse real data is obtained by subtracting a predetermined complex number from each element of data obtained by combining the reception side real part XOR data as a real part and the reception side imaginary part XOR data as an imaginary part, and multiplying by a predetermined amplitude coefficient. A receiver adjustment step that generates
Communication method comprising Rukoto equipped with. In the inverse operation step, four regions with a real axis and an imaginary axis on the complex plane as boundaries are used, and each element of the parallel signal is assigned to the region to which the point on the complex plane corresponding to the element belongs and The data after the inverse operation is replaced with the predetermined complex number indicating the region corresponding to a combination with the region to which the point on the complex plane corresponding to the element at the same position as the element of the receiving data series belongs. The communication method according to claim 7 , wherein the communication method is generated.

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