JP5699924B2 - 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 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 circumstances as described above, and aims to reduce PAPR that increases with an increase in FFT size and control the degree of PAPR reduction in OFDM communication. To do.

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;
IFFT means for generating first data by performing an inverse fast Fourier transform on the subcarrier modulation signal;
The complex plane is divided into a plurality of regions such that a plurality of points on the complex plane corresponding to each element of the first data exist in each region, and on the complex plane corresponding to each element of the first data Arithmetic means for adding a complex number determined for each region where a point is located to each element of the first data;
A transmission unit that generates a baseband signal based on a calculation result of the calculation unit, generates a transmission signal from the baseband signal, and transmits the transmission signal;
It is characterized by providing.

  Preferably, the calculation means divides the complex plane by a line passing through the origin of the complex plane.

  Preferably, the calculation means divides the complex plane by a straight line passing through the origin of the complex plane.

  Preferably, the arithmetic unit divides the complex plane into four regions having a real axis and an imaginary axis as a boundary, and the region in which a point on the complex plane corresponding to each element of the first data is located In each of the above, the complex number whose direction away from the origin of the complex plane is shown and the absolute value of the real part and the absolute value of the imaginary part are the same is added to each element of the first data.

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;
Serial-parallel conversion means for generating a parallel signal by serial-parallel conversion of the baseband signal;
The complex plane is divided into a plurality of regions such that there are a plurality of points on each complex plane corresponding to each element of the parallel signal, and the points on the complex plane corresponding to each element of the parallel signal are An inverse operation means for subtracting a complex number determined for each of the located regions from each element of the parallel signal;
FFT means for generating a subcarrier modulation signal by performing a fast Fourier transform of the calculation result of the inverse calculation means;
Demodulation means for demodulating the subcarrier modulation signal by a predetermined demodulation method;
It is characterized by providing.

  Preferably, the inverse operation means divides the complex plane by a line passing through the origin of the complex plane.

  Preferably, the inverse operation means divides the complex plane by a straight line passing through the origin of the complex plane.

  Preferably, the inverse operation means divides the complex plane into four regions having a real axis and an imaginary axis as a boundary, and the region in which a point on the complex plane corresponding to each element of the parallel signal is located , The complex number whose real part and absolute value are the same is subtracted from each element of the parallel 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;
IFFT step for generating first data by performing an inverse fast Fourier transform on the subcarrier modulation signal;
The complex plane is divided into a plurality of regions such that a plurality of points on the complex plane corresponding to each element of the first data exist in each region, and on the complex plane corresponding to each element of the first data A calculation step of adding a complex number determined for each region in which a point is located to each element of the first data;
A transmission step of generating a baseband signal based on a calculation result of the calculation step, generating a transmission signal from the baseband signal, and transmitting the transmission 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;
A serial-parallel conversion step for generating a parallel signal by serial-parallel conversion of the baseband signal;
The complex plane is divided into a plurality of regions such that there are a plurality of points on each complex plane corresponding to each element of the parallel signal, and the points on the complex plane corresponding to each element of the parallel signal are An inverse operation step of subtracting a complex number determined for each of the located regions from each element of the parallel signal;
An FFT step of generating a subcarrier modulation signal by performing a fast Fourier transform of the operation result of the inverse operation step;
A demodulation step for demodulating the subcarrier modulation signal by a predetermined demodulation method;
It is characterized by providing.

  According to the present invention, in OFDM communication, it is possible to reduce PAPR that increases as the FFT size increases, and to control the degree of PAPR reduction.

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 a division | segmentation of the complex plane in embodiment. It is a figure which shows the example of a movement of the point on the complex plane corresponding to each element after IFFT in embodiment. It is a figure which shows the movement of the point on the complex plane corresponding to each element after IFFT simulated with the same signal. It is a figure which shows the characteristic of PAPR simulated with the same signal. It is a figure which shows the movement of the point on the complex plane corresponding to each element after IFFT simulated with the random signal. It is a figure which shows the characteristic of PAPR simulated with the random signal.

  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, an IFFT unit 13, a calculation 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 FFT unit 33, an inverse operation 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 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 IFFT unit 13.

  The IFFT unit 13 performs IFFT of the subcarrier modulation signal, generates first data, and sends the first data to the calculation unit 14. The computing unit 14 divides the complex plane into a plurality of regions such that a plurality of points on the complex plane corresponding to each element of the first data exist in each region, and on the complex plane corresponding to each element of the first data. A complex number determined for each region where the point is located is added to each element of the first data. The complex number determined for each region is a constant value in the region. FIG. 3 is a diagram illustrating an example of division of the complex plane in the embodiment. For example, the calculation unit 14 divides the complex plane into four regions having a real axis and an imaginary axis as a boundary, and a range in which the deflection angle θ is 0 or more and less than π / 2 is the first region, and the deflection angle θ is π / 2 The range below π is the second region, the range of declination θ is π or more and less than 3 / 2π is the third region, and the range of declination θ is 3 / 2π or more and less than 2π is the fourth region.

Let u be the first data, and u ⁽¹⁾ be a set of elements in which the corresponding points on the complex plane are located in the first region among the elements of the first data. Similarly, for other regions, a set of elements whose corresponding points on the complex plane are located in the second region is u ⁽²⁾ , a set of elements located in the third region is u ⁽³⁾ , and the fourth region is Let u ⁽⁴⁾ be the set of positioned elements. Here, u is represented as a set of u ⁽¹⁾ , u ⁽²⁾ , u ⁽³⁾ , u ⁽⁴⁾ as in the following formula ⁽¹⁾ .

For example, the calculation unit 14 indicates a direction away from the origin of the complex plane in each region, and adds a complex number having the same absolute value of the real part and the absolute value of the imaginary part to each element of the first data. A set v ⁽ⁱ⁾ of the calculation results of the elements in each region obtained by performing the calculation on the set of elements u ⁽ⁱ⁾ in each region is expressed by the following equation (2). In the following equation (2), m is an arbitrary positive real number indicating the amount of movement of a point on the complex plane corresponding to each element, for example. J is an imaginary unit. a ⁽ⁱ⁾ and b ⁽ⁱ⁾ indicate moving directions of points on the complex plane corresponding to the respective elements. For example, a ⁽¹⁾ = 1, b ⁽¹⁾ = 1 for the first region, and a ⁽²⁾ = -1, for the second region, so as to indicate the direction away from the origin of the complex plane in each region. b ⁽¹⁾ = 1, a ⁽³⁾ = − 1 for the third region, b ⁽³⁾ = − 1, a ⁽⁴⁾ = 1 for the fourth region, and b ⁽⁴⁾ = − 1.

The calculation result v is expressed as a set of v ⁽¹⁾ , v ⁽²⁾ , v ⁽³⁾ , v ⁽⁴⁾ as in the following equation ⁽³⁾ .

  FIG. 4 is a diagram illustrating an example of element movement after IFFT in the embodiment. FIG. 4A shows the first data u, and FIG. 4B shows the calculation result v. When a complex number in which the absolute value of the real part and the absolute value of the imaginary part are the same is added to each element of the first data u, for example, indicating the direction away from the origin in each region as described above, in FIG. Each element moves in a direction away from the origin as indicated by the arrows. For example, two points located on the dotted line in the first region in FIG. 4A have the same phase, but in FIG. 4B, the two points have different phases. As described above, by adding the complex number determined for each region to each element, the phase of each element becomes a different value, so that PAPR can be reduced.

The method for setting the region on the complex plane is not limited to the method described above. The calculation unit 14 may divide the complex plane into an arbitrary number of equal areas or an arbitrary number of areas having different sizes. The calculation unit 14 may divide the complex plane by a line that does not pass through the origin. In this case, for example, when dividing by a straight line parallel to the real axis or the imaginary axis, it is easier to determine the region where each element of the first data is located than by dividing by a curve or the like. Further, the complex plane may be divided into four regions by curves passing through the origin of the complex plane, for example, lines representing Y = X ² and Y = −X ² . Further, for example, a straight line representing Y = −X is divided into two equal parts, and in the above formula (2), a ⁽¹⁾ = 1, b ⁽¹⁾ = 1, a ⁽²⁾ = −1, b ⁽²⁾ = − It may be 1. When dividing by a straight line passing through the origin of the complex plane, it is easier to determine the region where each element of the first data is located than when dividing by a curve passing through the origin of the complex plane. When the real axis and imaginary axis are divided into four equal parts, or when the real axis is divided into two equal parts, it is easy to deal with elements by determining whether the real part and imaginary part of the first data are positive or negative A region where a point on the complex plane is located can be specified.

The value of the complex number determined for each region is not limited to the above-described value, and the first data is moved by moving the point on the complex plane corresponding to each element of the parallel signal generated from the transmission signal received on the receiving side as described later. Any value can be used so long as it can be restored. As shown in FIG. 3, the complex plane is divided into four equal parts, for example, a ⁽¹⁾ = 1, b ⁽¹⁾ = 1 for the first region, and a ⁽²⁾ = 1, b ⁽¹ for the second region. ⁾ = 1, a ⁽³⁾ = − 1, b ⁽³⁾ = − 1 for the third area, a ⁽⁴⁾ = − 1, b ⁽⁴⁾ = − 1 for the fourth area. The absolute value of the real part and the absolute value of the imaginary part may be different values.

  Then, the calculation unit 14 generates a baseband signal from the calculation result v and sends it to the transmission unit 15. The transmission unit 15 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.

  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 and generates a baseband signal. Then, the baseband signal is serial-parallel converted to generate a parallel signal, which is sent to the inverse operation unit 34.

The inverse operation unit 34 divides the complex plane into a plurality of regions such that a plurality of points on the complex plane corresponding to each element of the parallel signal exist in each region, and the complex calculation plane 34 corresponds to each element of the parallel signal. A complex number determined for each region where the point is located is subtracted from each element of the parallel signal. The plurality of regions are the same as the plurality of regions generated by dividing the complex plane by the transmission-side arithmetic unit 14, and the complex number determined for each region is the same as that used by the transmission-side arithmetic unit 14. It is. For example, the inverse operation unit 34 divides the complex plane into four regions with the real axis and the imaginary axis as boundaries, and uses m (a ⁽ⁱ⁾ + jb ⁽ⁱ⁾ ) in the above equation (2) as a complex number.

The parallel signal matches the calculation result v generated by the calculation unit 14. Among the elements of the parallel signal, a set of elements whose corresponding points on the complex plane are located in the first region is v ⁽¹⁾ , a set of elements located in the second region is v ⁽²⁾ , and the third region is a set of position elements v ^(3), a set of elements located in the fourth region and v ^(4). A set r ⁽ⁱ⁾ of the calculation results of the elements in each region obtained by performing the calculation on the set of elements v ⁽ⁱ⁾ in each region is expressed by the following equation (4). Then, the following equation (5) is derived from the above equation (2) by modifying the above equation (4).

The calculation result r generated by the inverse calculation unit 34 matches the set of calculation results r ⁽ⁱ⁾ of the elements in each region, that is, the first data u, as shown in the following equation (6).

  The inverse calculation unit 34 sends the calculation result r to the FFT unit 33. The FFT unit 33 performs an FFT on the operation result r, generates a subcarrier modulation signal, and sends it 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.

  As described above, according to the communication device 1 according to the embodiment of the present invention, PAPR can be reduced in the OFDM communication scheme. It is possible to control the degree of PAPR reduction by changing the amount of movement of points on the complex plane.

  Next, the effect of the invention according to the present embodiment will be described by simulation. In the OFDM communication system, when the input signal is the same signal with the same data symbol, such as data that is all 0 or 1, or data in which 10 or 01 are alternately repeated, each subcarrier modulation signal Since the phases match, the PAPR of the baseband signal is maximized. By reducing the maximum value of PAPR, the range where linearity is required in the amplifier can be narrowed.

FIG. 5 is a diagram illustrating movement of points on the complex plane corresponding to each element after IFFT simulated with the same signal. The simulation was performed using the same signal as the input signal and QPSK as the modulation method. When the FFT size is 2048, when the complex number determined for each region is added to the first data after IFFT shown in FIG. 5A, the calculation result shown in FIG. 5B is obtained. In the simulation, m in the above equation (2) is set to 0.02, and a ⁽ⁱ⁾ and b ⁽ⁱ⁾ are shown in the above example to indicate the direction in which the complex number determined for each region is away from the origin of the complex plane. Was set as follows.

  FIG. 6 is a diagram showing the characteristics of PAPR simulated with the same signal. The horizontal axis is the FFT size, and the vertical axis is PAPR (unit: dB). A simulation for generating a baseband signal and calculating a PAPR was performed for the related art and the invention according to the present embodiment using the same signal as the input signal. QPSK was used as a modulation method, and the FFT size was changed to 4, 8, 16, 32, 64, 128, 256, 512, 1024, and 2048, and the simulation was repeated, and the average value of PAPR at each FFT size was plotted.

The prior art is a method of generating a baseband signal from a subcarrier modulation signal without adding the above-described calculation in the calculation unit 14. For the invention according to the present embodiment, m, a ⁽ⁱ⁾ and b ⁽ⁱ⁾ in the above equation (2) are set to the same values as in the above simulation. In the above equation (2), when m = 0, no calculation is performed by the calculation unit 14, and PAPR is the same as that of the prior art. By changing the value of m indicating the amount of movement of the point on the complex plane, the degree of movement of the point on the complex plane in FIG. 5 changes, and the degree of PAPR reduction changes.

  In FIG. 6, the PAPR of the prior art is a solid line graph in which plot points are represented by squares, and the PAPR in the present embodiment is a dotted line graph in which plot points are represented by triangles. In the present embodiment, an increase in PAPR accompanying an increase in FFT size is reduced. When the FFT size is 2048, the PAPR of the prior art is 33.1 dB, whereas the PAPR of the present embodiment is 29.1 dB, and the PAPR is reduced by 4.0 dB.

FIG. 7 is a diagram illustrating movement of points on the complex plane corresponding to each element after IFFT simulated with a random signal. Using a random signal as an input signal, that is, a signal that is not the same signal, a simulation similar to the simulation using the same signal as the input signal was performed. M, a ⁽ⁱ⁾ and b ⁽ⁱ⁾ in the above equation (2) were set to the same values as in the above simulation. When the FFT size is 2048, when a complex number determined for each region is added to the first data after IFFT shown in FIG. 7A, the calculation result shown in FIG. 7B is obtained.

  FIG. 8 is a diagram illustrating PAPR characteristics simulated with random signals. The horizontal axis is the FFT size, and the vertical axis is PAPR (unit: dB). Using a random signal as the input signal, a simulation similar to the simulation using the same signal as the input signal was performed for the related art and the invention according to the present embodiment.

  In FIG. 8, the PAPR of the prior art is a solid line graph in which plotted points are represented by squares, and the PAPR in the present embodiment is a dotted line graph in which plotted points are represented by triangles. In the present embodiment, an increase in PAPR accompanying an increase in FFT size is reduced. When the FFT size is 2048, the PAPR of the prior art is 9.1 dB, whereas the PAPR of the present embodiment is 5.5 dB, and the PAPR is reduced by 3.6 dB. According to the present embodiment, PAPR is reduced not only when the input signal is the same signal but also when it is a random signal.

  Therefore, according to the invention according to the present embodiment in which the degree of PAPR reduction can be controlled, it has been found that, in OFDM communication, PAPR that increases as the FFT size increases can be reduced.

  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.

  The IFFT unit 13 may be configured to perform IDFT instead of IFFT, and the FFT unit 33 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 IFFT part 14 Calculation part 15 Transmission part 20 Controller 21 CPU
22 I / O
23 RAM
24 ROM
31 demodulator 32 parallel-serial converter 33 FFT unit 34 inverse operation unit 35 receiver 36 transmission / reception switching unit

Claims (10)

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;
IFFT means for generating first data by performing an inverse fast Fourier transform on the subcarrier modulation signal;
The complex plane is divided into a plurality of regions such that a plurality of points on the complex plane corresponding to each element of the first data exist in each region, and on the complex plane corresponding to each element of the first data Arithmetic means for adding a complex number determined for each region where a point is located to each element of the first data;
A transmission unit that generates a baseband signal based on a calculation result of the calculation unit, generates a transmission signal from the baseband signal, and transmits the transmission signal;
A communication device comprising:   The communication device according to claim 1, wherein the arithmetic unit divides the complex plane by a line passing through an origin of the complex plane.   The communication device according to claim 2, wherein the arithmetic unit divides the complex plane by a straight line passing through an origin of the complex plane.   The arithmetic means divides the complex plane into four regions having a real axis and an imaginary axis as a boundary, and in each of the regions where points on the complex plane corresponding to the elements of the first data are located. 4. The complex number indicating a direction away from the origin of the complex plane and adding the complex number having the same absolute value of the real part and the absolute value of the imaginary part to each element of the first data. Communication machine. 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;
Serial-parallel conversion means for generating a parallel signal by serial-parallel conversion of the baseband signal;
The complex plane is divided into a plurality of regions such that there are a plurality of points on each complex plane corresponding to each element of the parallel signal, and the points on the complex plane corresponding to each element of the parallel signal are An inverse operation means for subtracting a complex number determined for each of the located regions from each element of the parallel signal;
FFT means for generating a subcarrier modulation signal by performing a fast Fourier transform of the calculation result of the inverse calculation means;
Demodulation means for demodulating the subcarrier modulation signal by a predetermined demodulation method;
A communication device comprising:   6. The communication apparatus according to claim 5, wherein the inverse operation unit divides the complex plane by a line passing through an origin of the complex plane.   The communication device according to claim 6, wherein the inverse operation unit divides the complex plane by a straight line passing through an origin of the complex plane.   The inverse calculation means divides the complex plane into four regions having a real axis and an imaginary axis as a boundary, and in each of the regions where points on the complex plane corresponding to the elements of the parallel signal are located. The communication according to claim 7, wherein the complex number indicating a direction away from the origin of the complex plane and subtracting the complex number having the same real part absolute value and imaginary part absolute value from each element of the parallel signal. Machine. 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;
IFFT step for generating first data by performing an inverse fast Fourier transform on the subcarrier modulation signal;
The complex plane is divided into a plurality of regions such that a plurality of points on the complex plane corresponding to each element of the first data exist in each region, and on the complex plane corresponding to each element of the first data A calculation step of adding a complex number determined for each region in which a point is located to each element of the first data;
A transmission step of generating a baseband signal based on a calculation result of the calculation step, generating a transmission signal from the baseband signal, and transmitting the transmission 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;
A serial-parallel conversion step for generating a parallel signal by serial-parallel conversion of the baseband signal;
The complex plane is divided into a plurality of regions such that there are a plurality of points on each complex plane corresponding to each element of the parallel signal, and the points on the complex plane corresponding to each element of the parallel signal are An inverse operation step of subtracting a complex number determined for each of the located regions from each element of the parallel signal;
An FFT step of generating a subcarrier modulation signal by performing a fast Fourier transform of the operation result of the inverse operation step;
A demodulation step for demodulating the subcarrier modulation signal by a predetermined demodulation method;
A communication method comprising:

Images