JP6089613B2 - 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 the input signal with a predetermined modulation method to generate a modulation signal;
Based on a predetermined redundant signal is a set of data, and each element of the modulation signal, and each element of said redundancy signal subjected to shift the data by a predetermined number of times in a predetermined direction located alternately, the number of elements Insertion means for generating post-insertion data that matches the size of the fast Fourier transform;
IFFT means for performing inverse fast Fourier transform on the post-insertion data;
Combining means for combining the operation results of the IFFT means to generate a baseband signal;
Determining means for calculating a peak-to-average power ratio of the baseband signal and determining whether the peak-to-average power ratio satisfies a predetermined criterion;
Repeating means for repeatedly performing the processing of the inserting means, the IFFT means, the synthesizing means, and the determining means until the baseband signal satisfying the predetermined criteria is detected, changing the predetermined number of times,
Transmitting means for generating and transmitting a transmission signal based on the baseband signal satisfying the predetermined criterion;
It is characterized by providing.

  Preferably, the inserting means converts, as the redundant signal, an autocorrelation value between the same data series not shifted in data and an autocorrelation value between the data series shifted arbitrarily in the data. An arbitrary data series having higher autocorrelation characteristics is used.

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 generating a baseband signal by receiving a transmission signal generated based on frequency domain data in which each element of the redundant signal and each element of the modulation signal shifted alternately in a predetermined direction are located ;
FFT means for performing serial-parallel conversion on the baseband signal and performing fast Fourier transform to generate converted data;
A demodulator that extracts an element at a predetermined position of the converted data according to a position at which the element of the redundant signal is inserted, and demodulates the data including the extracted element by a predetermined modulation method;
It is characterized by providing.

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 the input signal with a predetermined modulation method to generate a modulated signal;
Based on a predetermined redundant signal is a set of data, and each element of the modulation signal, and each element of said redundancy signal subjected to shift the data by a predetermined number of times in a predetermined direction located alternately, the number of elements An insertion step for generating post-insertion data matching the size of the fast Fourier transform;
IFFT step for performing inverse fast Fourier transform of the post-insertion data;
A combining step of combining the operation results of the IFFT step to generate a baseband signal;
Determining a peak-to-average power ratio of the baseband signal and determining whether the peak-to-average power ratio satisfies a predetermined criterion; and
A repetition step of repeatedly performing the processing of the insertion step, the IFFT step, the synthesis step, and the determination step by changing the predetermined number of times until the baseband signal satisfying the predetermined criterion is detected;
A transmission step of generating and transmitting a transmission signal based on the baseband signal satisfying the predetermined criterion;
It is characterized by providing.

  Preferably, in the inserting step, as the redundant signal, an autocorrelation value between the same data series that has not been subjected to data shift is changed to an autocorrelation value between the data series that has undergone arbitrary data shift. An arbitrary data series having higher autocorrelation characteristics is used.

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 generating a baseband signal by receiving a transmission signal generated based on data in a frequency domain in which each element of the redundant signal and each element of the modulation signal shifted alternately in a predetermined direction are located ;
An FFT step of performing serial-parallel conversion of the baseband signal and performing fast Fourier transform to generate converted data;
A demodulating step of extracting an element at a predetermined position of the converted data according to a position at which the element of the redundant signal is inserted, and demodulating the data including the extracted element by a predetermined modulation method;
It is characterized by providing.

  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 insertion process which the insertion part which concerns on embodiment performs. It is a figure which shows the example from which the insertion process which the insertion part which concerns on embodiment performs differs. 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 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 example of the signal point arrangement | positioning figure of the data after insertion 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 example of the signal point arrangement | positioning figure of the data after insertion 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.

  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, an insertion unit 13, an IFFT unit 14, a synthesis unit 15, a determination unit 16, a transmission unit 17, 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 extraction unit 33, an FFT unit 34, a reception unit 35, and a transmission / reception switching unit 36. . 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. The predetermined modulation method is, for example, QPSK (Quadrature Phase-Shift Keying). The serial / parallel conversion unit 12 performs serial / parallel conversion on the modulated signal and sends it to the insertion unit 13. The insertion unit 13 inserts a redundant signal element, which is a set of predetermined data, at an arbitrarily determined position of the modulation signal subjected to serial / parallel conversion, and generates post-insertion data whose number of elements matches the FFT size. The insertion unit 13 sends the post-insertion data to the IFFT unit 14.

  If the information on the insertion position of the redundant signal element is shared between the transmitting side and the receiving side, the position at which the redundant signal element is inserted can be arbitrarily determined. The insertion unit 13 uses an autocorrelation value between, for example, a random signal or an autocorrelation value with the same data sequence that has not been shifted as a redundant signal, and a data sequence with an arbitrary shift of data. It is possible to use an arbitrary data series having an autocorrelation characteristic which is higher than that of. In the case of using a data series having autocorrelation characteristics, a data series subjected to arbitrary data shift has a value of at least one element different from that of a data series not subjected to data shift.

  As a data sequence having autocorrelation characteristics, for example, a CAZAC (Constant Amplitude Zero Auto-Correlation) sequence or a PN (Pseudorandom Noise) sequence can be used. Using a data series with autocorrelation characteristics that have a lower PAPR (Peak-to-Average Power Ratio) than the modulated signal as the redundant signal, insert the redundant signal element at an arbitrarily defined position in the modulated signal By doing so, it becomes possible to reduce PAPR.

  Assuming that the number of elements of the modulation signal is M, the modulation signal subjected to serial / parallel conversion is expressed by the following equation (1). The modulated signal d in the following description means a modulated signal that has been serial-parallel converted. If the FFT size is N, the redundant signal r is expressed by the following equation (2). The redundant signal r may be a serial signal or a parallel signal.

  The insertion unit 13 sets, for example, M = N / 2, and each element of the redundant signal r immediately after each element of the modulated signal d so that each element of the modulated signal d and each element of the redundant signal r are alternately positioned. Insert in order and generate post-insertion data. The post-insertion data is expressed by the following formula (3). The subscript T in the formula indicates that the matrix is transposed.

The insertion unit 13 shifts the data a predetermined number of times in a predetermined direction with respect to the redundant signal r that is a set of predetermined data, and the element of the redundant signal r in which the data is shifted to an arbitrarily determined position of the modulation signal d May be inserted. For example, the redundant signal r ^(k) shifted k times in the left direction is expressed by the following equation (4). K in the parentheses of the subscript represents the number of shifts. The direction in which the data of the redundant signal r is shifted is not limited to the left direction, but is arbitrary.

The insertion unit 13 sequentially inserts each element of the redundant signal r ^(k) immediately after each element of the modulated signal d so that each element of the modulated signal d and each element of the redundant signal r ^(k) are alternately positioned. Then, post-insertion data is generated. The post-insertion data is expressed by the following equation (5).

  FIG. 3 is a diagram illustrating an example of an insertion process performed by the insertion unit according to the embodiment. The number of elements of the modulation signal d and the redundant signal r is 8, and the FFT size is 16. The horizontal axis is the element, and the vertical axis is the value of the element. For ease of explanation, only the real part of each element is shown. The element of the redundant signal r represented by the hatched square in FIG. 3B is inserted at an arbitrarily determined position of the modulation signal d represented by the white square in FIG. Generated. FIGS. 3C, 3D, 3E, and 3F are examples of post-insertion data generated by inserting an element of the redundant signal r at an arbitrarily determined position of the modulation signal d.

  As shown in FIG. 3 (c), elements of the redundant signal r may be inserted into the modulation signal d so that the elements of the redundant signal r are not continuous, as shown in FIGS. 3 (d) and 3 (e). In addition, the redundant signal r may be inserted into the modulation signal d so that a part of the redundant signal r is continuous. The number of elements of the continuous redundant signal r may be different as shown in FIG. 3D, or may be the same as shown in FIG. Further, as shown in FIG. 3F, all elements of the redundant signal r may be inserted before the modulation signal d. As shown in FIG. 3, the redundant signal r can be inserted at an arbitrarily determined position of the modulated signal d, and the redundant signal r is modulated at regular intervals like a pilot signal used for equalization processing on the receiving side. There is no need to insert into d.

  FIG. 4 is a diagram illustrating a different example of the insertion process performed by the insertion unit according to the embodiment. The way of viewing the figure is the same as in FIG. The number of elements of the modulation signal d and the number of elements of the redundant signal r may be different values. 4A shows a modulation signal d having 11 elements, and FIG. 4B shows a redundant signal r having 5 elements. The redundant signal r shown in FIG. 4 (b) may be inserted into the modulated signal d shown in FIG. 4 (a) to generate post-insertion data as shown in FIG. 4 (c). FIG. 4D shows a modulation signal d having 6 elements, and FIG. 4E shows a redundant signal r having 10 elements. The redundant signal r shown in FIG. 4 (e) may be inserted into the modulation signal d shown in FIG. 4 (d) to generate post-insertion data as shown in FIG. 4 (f).

  The IFFT unit 14 performs IFFT of the inserted data and sends the calculation result to the synthesis unit 15. The synthesizer 15 synthesizes the operation results of the IFFT unit 14 to generate a baseband signal, and sends the baseband signal to the determination unit 16. The determination unit 16 calculates the PAPR of the baseband signal and determines whether or not the PAPR meets a predetermined standard. If the PAPR of the baseband signal does not meet a predetermined standard, the determination unit 16 notifies the insertion unit 13 to that effect. Then, the inserting unit 13 generates new post-insertion data using different redundant signals r. The insertion unit 13 generates new post-insertion data using a different redundant signal r, and the IFPR unit 14, the synthesis unit 15, and the determination unit 16 perform the above processing based on the new post-insertion data. Repeat until a baseband signal matching a predetermined criterion is detected. It is possible to reduce the PAPR of the baseband signal by repeating until the PAPR detects a baseband signal that matches a predetermined criterion.

  The insertion unit 13 inserts the redundant signal r shifted a predetermined number of times in a predetermined direction into an arbitrary predetermined position of the modulation signal to generate post-insertion data, and the baseband whose PAPR meets a predetermined standard Until the signal is detected, the above process is repeated by changing the number of shifts. When a random signal is used as the redundant signal r, the probability that a random signal that has undergone arbitrary data shift matches a random signal that has not undergone data shift is extremely low. Further, when a data series having autocorrelation characteristics is used as the redundant signal r, the value of at least one element is different in a data series subjected to arbitrary data shift compared to a data series not subjected to data shift. By changing the number of shifts of a certain redundant signal r and repeating the above process, it is possible to reduce the PAPR of the baseband signal in the same manner as when the above process is repeated for a plurality of different redundant signals r prepared in advance. become.

  The controller 20 controls the insertion unit 13, the IFFT unit 14, the synthesis unit 15, and the determination unit 16 to repeat the above-described processing, and performs an operation as a repetition unit.

  If the PAPR of the baseband signal matches a predetermined criterion, the determination unit 16 sends the baseband signal to the transmission unit 17. The determination unit 16 is configured to repeat the above-described processing for all redundant signals r prepared in advance to detect a baseband signal having the lowest PAPR, or to detect a baseband signal having a PAPR smaller than a predetermined value. can do. The determination unit 16 can be configured to detect the baseband signal having the lowest PAPR by repeating the above-described processing until the data shift of the redundant signal r in the insertion unit 13 is completed.

  The transmission unit 17 generates a transmission signal from the received baseband signal, and transmits the transmission signal to another device via the transmission / reception switching unit 36 and the antenna 10.

  FIG. 5 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 a predetermined modulation method to generate a modulation signal, and the serial / parallel conversion unit 12 performs serial / parallel conversion on the modulation signal (step S110). The insertion unit 13 inserts an element of the redundant signal r, which is a set of predetermined data, at an arbitrarily determined position of the modulation signal d, and generates post-insertion data whose number of elements matches the FFT size (step S120). The IFFT unit 14 performs IFFT of the inserted data (step S130). The synthesizer 15 synthesizes the calculation results of the IFFT unit 14 to generate a baseband signal (step S140).

  The determination unit 16 calculates the PAPR of the baseband signal and determines whether or not the PAPR matches a predetermined standard (step S150). If the PAPR of the baseband signal does not meet the predetermined standard (step S160: N), the process returns to step S120, and the above-described processing is repeated for different redundant signals r. If the PAPR of the baseband signal matches a predetermined criterion (step S160: Y), the transmission unit 17 generates a transmission signal from the baseband signal that matches the predetermined criterion, and transmits / receives the transmission / reception switching unit 36 and the antenna 10. Then, a transmission signal is sent to another device via (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 FFT on the baseband signal that has been subjected to serial-parallel conversion, generates converted data, and sends the converted data to the extraction unit 33.

  The extraction unit 33 extracts an element at an arbitrarily determined position in the converted data, generates post-extraction data including the extracted element, and sends the extracted data to the parallel-serial conversion unit 32. The arbitrarily determined position is the position of the element of the modulation signal d in the post-insertion data generated on the transmission side. As described above, the position can be arbitrarily determined as long as the position information is shared between the transmission side and the reception side.

  The parallel / serial converter 32 performs parallel / serial conversion on the extracted data and sends the data to the demodulator 31. The demodulator 31 demodulates the extracted data subjected to parallel-serial conversion using a predetermined modulation method, and restores the input signal.

  FIG. 6 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 FFT of the baseband signal that has been subjected to serial-parallel conversion to generate post-conversion data (step S220). The extraction unit 33 extracts an element at an arbitrarily determined position in the converted data, and generates post-extraction data (step S230). The parallel-serial converter 32 performs parallel-serial conversion on the extracted data, and the demodulator 31 demodulates the extracted data subjected to parallel-serial conversion using a predetermined modulation method to restore the input signal (step S240).

  As described above, according to communication apparatus 1 according to the embodiment of the present invention, a baseband signal is generated based on post-insertion data generated by inserting an element of redundant signal r into modulated signal d in an OFDM communication system. By repeating this operation for different redundant signals r until a baseband signal satisfying a predetermined criterion is detected, the PAPR can be reduced. In addition, repeating the above-described processing for different redundant signals r is a simpler method than the repetition of calculation processing by the sequential determination method, and according to the communication device 1 according to the embodiment of the present invention, PAPR is reduced. It is possible to simplify the processing to be performed.

(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 system 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 for generating a baseband signal by performing serial-parallel conversion on a signal obtained by modulating an input signal by a predetermined modulation method without performing the insertion processing as described above, and performing IFFT.

  Here, as an example, by using the modulation signal d and the redundancy signal r each having 1024 elements, each element of the modulation signal d is alternately positioned so that each element of the modulation signal d and each element of the redundancy signal r are alternately located. A simulation is performed using post-insertion data generated by inserting each element of the redundant signal r in order immediately after the element. A CAZAC sequence is used as the redundant signal r. FIG. 7 is a diagram illustrating an example of a signal point arrangement diagram of post-insertion data in the communication device according to the embodiment. It can be seen that the phase of each element of the post-insertion data is more dispersed than the QPSK signal point arrangement diagram.

  FIG. 8 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 (unit: dB), and the vertical axis is PAPR CCDF. The CCDF characteristic of the PAPR of the prior art is a thin solid line graph, and the CCDF characteristic of the PAPR of the invention according to the present embodiment is a solid line graph. The PAPR of the invention according to the present embodiment is reduced as compared with the prior art.

  A simulation was similarly performed for BER (Bit Error Rate). FIG. 9 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. 9, 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.

  As another example, a PN sequence is used as the redundant signal r, and a simulation is performed using post-insertion data generated by sequentially inserting each element of the redundant signal r immediately after each element of the modulated signal d in the same manner as the above-described simulation. Do. FIG. 10 is a diagram illustrating an example of a signal point arrangement diagram of post-insertion data in the communication device according to the embodiment. FIG. 10A is a signal point arrangement diagram of post-insertion data when a PN sequence is used as the redundant signal r, and FIG. 10B shows only π / 4 for each element of the PN sequence as the redundant signal r. It is the signal point arrangement | positioning figure of the data after insertion at the time of using the data which rotated the phase by-(pi) / 4 about the data which rotated the phase, or each element of the PN series.

  FIG. 11 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 (unit: dB), and the vertical axis is PAPR CCDF. As shown in FIG. 10A, a simulation similar to the above-described simulation was performed using a PN sequence as the redundant signal r. The CCDF characteristic of the PAPR of the prior art is a thin solid line graph, and the CCDF characteristic of the PAPR of the invention according to the present embodiment is a solid line graph. The PAPR of the invention according to the present embodiment is reduced as compared with the prior art.

  A similar simulation was performed for BER. FIG. 12 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. 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. 12, 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.

  The simulation was performed using the same signal in which the phase of each element of the signal modulated by a predetermined modulation method is matched, for example, the element values are all 0, as an input signal. The PAPR of the prior art is 33.11 dB, while the PAPR of the baseband signal based on the post-insertion data generated using the CAZAC sequence for the redundant signal r is 27.36 dB. The PAPR of the baseband signal based on the post-insertion data generated using the PN sequence for the redundant signal r is 27.11 dB, and data obtained by rotating the PN sequence elements by π / 4 is used for the redundant signal r. The PAPR of the baseband signal based on the generated post-insertion data was 27.11 dB. Even in the case where the input signals are the same signal, the PAPR of the invention according to the present embodiment is reduced compared to the prior art regardless of which redundant signal r is used.

  Further, as shown in FIGS. 3C to 3F, when the simulation was performed by changing the insertion position of the element of the redundant signal r, the degree of PAPR reduction changed slightly.

  According to the above-described simulation, in the present embodiment, a baseband signal that satisfies a predetermined standard is generated based on post-insertion data that is generated by inserting an element of the redundant signal r into the modulation signal d. It was found that PAPR can be reduced by repeating for different redundant signals r until detection.

  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. In the above-described embodiment, the redundant signal r element is inserted into the modulated signal that has been serial-parallel converted by the serial-parallel conversion unit 12, but the order of the serial-parallel conversion unit 12 and the insertion unit 13 may be changed. That is, an element of the redundant signal r is inserted into the modulation signal generated by modulating the input signal by a predetermined modulation method to generate post-insertion data, and the post-insertion data is serial-parallel converted by the serial-parallel converter 12. It may be configured.

  The redundant signal r used by the insertion unit 13 is not limited to a data sequence having autocorrelation characteristics such as a CAZAC sequence or a PN sequence, and may be a random signal. The insertion unit 13 may be configured to use, for example, a plurality of random signals having variations in the phase of each element as the redundant signal r. 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 Insertion part
14 IFFT section
15 Synthesizer
16 Judgment part
17 Transmitter
20 controller
21 CPU
22 I / O
23 RAM
24 ROM
31 Demodulator
32 Parallel to serial converter
33 Extractor
34 FFT section
35 Receiver
36 Transmission / reception switching unit

Claims (6)

A communication device that communicates with other devices by orthogonal frequency division multiplex communication wireless communication,
Modulation means for modulating the input signal with a predetermined modulation method to generate a modulation signal;
Based on a predetermined redundant signal is a set of data, and each element of the modulation signal, and each element of said redundancy signal subjected to shift the data by a predetermined number of times in a predetermined direction located alternately, the number of elements Insertion means for generating post-insertion data that matches the size of the fast Fourier transform;
IFFT means for performing inverse fast Fourier transform on the post-insertion data;
Combining means for combining the operation results of the IFFT means to generate a baseband signal;
Determining means for calculating a peak-to-average power ratio of the baseband signal and determining whether the peak-to-average power ratio satisfies a predetermined criterion;
Repeating means for repeatedly performing the processing of the inserting means, the IFFT means, the synthesizing means, and the determining means until the baseband signal satisfying the predetermined criteria is detected, changing the predetermined number of times,
Transmitting means for generating and transmitting a transmission signal based on the baseband signal satisfying the predetermined criterion;
A communication device comprising: In the insertion means, as the redundant signal, an autocorrelation value between the same data series in which data is not shifted is higher than an autocorrelation value between the data series in which data is arbitrarily shifted 2. The communication apparatus according to claim 1, wherein an arbitrary data series having autocorrelation characteristics is used. A communication device that communicates with other devices by orthogonal frequency division multiplex communication wireless communication,
Receiving means for generating a baseband signal by receiving a transmission signal generated based on frequency domain data in which each element of the redundant signal and each element of the modulation signal shifted alternately in a predetermined direction are located ;
FFT means for performing serial-parallel conversion on the baseband signal and performing fast Fourier transform to generate converted data;
A demodulator that extracts an element at a predetermined position of the converted data according to a position at which the element of the redundant signal is inserted, and demodulates the data including the extracted element by a predetermined modulation method;
A communication device 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 modulation step of modulating the input signal with a predetermined modulation method to generate a modulated signal;
Based on a predetermined redundant signal is a set of data, and each element of the modulation signal, and each element of said redundancy signal subjected to shift the data by a predetermined number of times in a predetermined direction located alternately, the number of elements An insertion step for generating post-insertion data matching the size of the fast Fourier transform;
IFFT step for performing inverse fast Fourier transform of the post-insertion data;
A combining step of combining the operation results of the IFFT step to generate a baseband signal;
Determining a peak-to-average power ratio of the baseband signal and determining whether the peak-to-average power ratio satisfies a predetermined criterion; and
A repetition step of repeatedly performing the processing of the insertion step, the IFFT step, the synthesis step, and the determination step by changing the predetermined number of times until the baseband signal satisfying the predetermined criterion is detected;
A transmission step of generating and transmitting a transmission signal based on the baseband signal satisfying the predetermined criterion;
A communication method comprising: In the inserting step, as the redundant signal, an autocorrelation value with the same data series that has not been subjected to data shift is higher than an autocorrelation value with a data series that has undergone arbitrary data shift 5. The communication method according to claim 4 , wherein an arbitrary data series having autocorrelation characteristics is used. 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 generating a baseband signal by receiving a transmission signal generated based on data in a frequency domain in which each element of the redundant signal and each element of the modulation signal shifted alternately in a predetermined direction are located ;
An FFT step of performing serial-parallel conversion of the baseband signal and performing fast Fourier transform to generate converted data;
A demodulating step of extracting an element at a predetermined position of the converted data according to a position at which the element of the redundant signal is inserted, and demodulating the data including the extracted element by a predetermined modulation method;
A communication method comprising:

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