JP6858405B2 - Communication method and communication device - Google Patents

Description

The present invention relates to multi-carrier communication.

Along with the full-scale operation of terrestrial digital broadcasting, there is a demand for the provision of more advanced broadcasting services using ultra-high-definition video technology (4K / 8K). In terrestrial mobile communications, research and development are underway toward the international standardization of fifth-generation mobile communication systems, which have high frequency utilization efficiency and enable high-speed, large-capacity communications, multiple connections, and the like. In the terrestrial digital broadcasting and the 4GLTE system, an OFDM system having an interference resistance characteristic against narrowing of the occupied frequency band and frequency selective interference is adopted.

Ken Umeno, "Spectral Spread Communication Based on Almost Periodic Functions-Differences between Almost Periodic and Chaos-", IEICE Tech., Vol.114, no.250 NLP2014-64, pp.87-90 (2014), Institute of Electronics, Information and Communication Engineers

In the OFDM method using a synchronized periodic function, PAPR (Peak to average power ratio) is generally high, and communication quality is likely to deteriorate. In addition, there is a drawback that the occupied bandwidth is expanded and the adjacent interference is increased due to the intermodulation distortion in the transmission system, and there remains a problem from the effective use of frequency.

The present invention has been made in connection with solving the above problems.

One aspect of the present invention is a communication method, which comprises performing communication using a multi-carrier, and the frequency arrangement of the multi-carrier is asynchronous between the multi-carriers and the frequency intervals are unequal. Almost periodic frequency arrangement is included. Here, communication is meant to include broadcasting. Another aspect of the present invention is a communicator, comprising a modulator that modulates a subcarrier based on a transmission code. The frequency arrangement of the subcarriers includes an almost periodic arrangement that is asynchronous with respect to the frame time length.

It is a flowchart which shows the determination procedure of the general periodic frequency arrangement. It is a block diagram of the almost periodic frequency arrangement generator. It is the figure which plotted the approximate periodic frequency obtained from the prime number. It is a schematic diagram of the evenly spaced frequency arrangement. It is a figure which shows the total number of prime numbers vs. the frequency standard deviation. It is a block diagram of a communication device. It is explanatory drawing of the general periodic frequency multiplex modulation. It is a block diagram of an output part and an input part. It is a block diagram of a multi-access communication system. It is a schematic diagram of PAPR simulation. It is a block diagram of the transmission part which includes the PAPR compensation part. It is a block diagram of the PAPR compensation part. It is a figure which shows PAPR.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[1. Outline of the embodiment]
The communication method according to the embodiment is a communication method including communication using a multi-carrier. The multicarrier frequency arrangement includes an almost periodic frequency arrangement in which the frequency intervals between carriers are non-equal intervals. In the embodiment, the almost periodic frequency arrangement is a frequency arrangement that is asynchronous between any subcarriers with respect to the frame time length that separates the signal trains, and includes non-equidistant arrangements. Almost periodic frequency (Almost Periodic Frequency) refers to the frequency of each subcarrier on the almost periodic frequency arrangement.

Here, in the conventional OFDM, the frequency intervals of the subcarriers are set at equal intervals so as to satisfy the orthogonality condition so that the carriers (subcarriers) do not interfere with each other. In OFDM, by arranging subcarriers at equal intervals that satisfy the orthogonality condition, interference between subcarriers can be prevented even if the frequency intervals of the subcarriers are reduced so that the bands of the subcarriers overlap. However, in OFDM, the PAPR tends to be high because the subcarriers are periodically arranged at equal intervals. On the other hand, in the present embodiment, since each subcarrier has an almost periodic frequency arrangement that is asynchronous with respect to the frame time length, it is possible to suppress an increase in PAPR even if the number of carriers is increased.

Almost periodic frequency arrangement can be determined based on the almost periodic function. Almost periodic functions can be based on the Weyl series. The Weyl series is based on Weyl's uniform distribution theorem that the fractional part, which is an integral multiple of an irrational number, is uniformly distributed in [0,1]. In addition, the expanded fractional part, which is a multiple of the real number, is also uniformly distributed in [0,1]. Almost periodic frequency may be determined from a group of irrational numbers, may be determined from a group of rational numbers that limit the number of effective digits of the irrational number, or a rational number that approximates an irrational number determined based on an irrational function. It may be determined from the group.

Almost periodic frequency arrangement is generated from prime numbers using the almost periodic function by determining the reference frequency arrangement in which the frequency intervals of the subcarriers are evenly spaced when the frequency intervals between the subcarriers are close to equal intervals. It can be determined by selecting an almost periodic frequency close to the reference carrier frequency in the reference frequency arrangement in which the frequency intervals between the subcarriers are evenly spaced from the obtained approximate periodic frequency group. Almost periodic frequencies can be generated using an almost periodic function. As the reference frequency arrangement, it is preferable that the frequency arrangement satisfies the orthogonality condition and the frequency intervals between carriers are equal as in the carrier frequency arrangement in OFDM, but the optimum reference frequency arrangement may be determined depending on the communication mode to be applied. good. The reference carrier frequency is each carrier frequency in the reference frequency arrangement. When an almost periodic frequency close to the reference carrier frequency is determined, the carriers can be densely arranged and interference between carriers can be suppressed.

The composite almost periodic frequency arrangement includes at least a first partial almost periodic frequency arrangement and a second partial almost periodic frequency arrangement other than the first partial almost periodic frequency arrangement, and the second partial periodic frequency arrangement other than the first part. The frequency arrangement can be easily obtained by frequency-shifting the first partial periodic frequency arrangement. The first partial almost periodic frequency arrangement can be determined based on the almost periodic function. The second part almost periodic frequency arrangement other than the first part almost periodic frequency arrangement is obtained by frequency-shifting the first part almost periodic frequency arrangement, respectively, with respect to the frame time length, except for the first part and the first part. Subcarriers can be asynchronous, and almost periodic frequency arrangements can be obtained. It should be noted that a plurality of partial general periodic frequency arrangements may be obtained from the first partial general periodic frequency arrangement by frequency shifting. That is, frequency shifting can provide one or more partial almost periodic frequency arrangements. When obtaining a plurality of partial general periodic frequency arrangements, the amount of frequency shift from the first partial general periodic frequency arrangement may be different from each other.

The frequency arrangement of the multicarrier may include a blank portion of the subcarrier. The blank portion of the carrier may be used, for example, as a guard section for preventing interference between subcarriers, or may be used as a noise measurement section.

The frequency arrangement of the multicarrier may include an almost periodic frequency arrangement and also partially include a frequency arrangement other than the almost periodic frequency arrangement. For example, the multicarrier frequency arrangement maintains the asynchrony of the almost periodic frequency arrangement even if it includes a frequency arrangement in which the subcarriers are synchronized with respect to the frame time length. The multicarrier frequency arrangement may include pilot frequencies. Further, the carrier wave may be reproduced using the pilot frequency.

Each carrier included in the multicarrier may be subjected to N-value multiplex modulation such as QPSK or N-QAM in order to increase transmission efficiency, power level modulation may be performed, or phase modulation. May be done. A window function may be applied to the multicarrier frame to make the spectrum uniform.

In the transmission system of multi-carrier communication, the signal on the time axis of the multi-carrier having the approximate periodic frequency arrangement is subjected to FFT processing, the transmission frequency is band-limited, and then IFFT processing is performed to convert it into a signal on the time axis. Can be sent.

In the reception system of multi-carrier communication, the same general-period frequency arrangement as that used for transmission is FFT-processed in advance, and the cross-correlation value is obtained after the FFT processing of the multi-carrier reception signal of the general-period frequency arrangement. Therefore, the modulated code of the transmitted almost periodic frequency can be detected. The cross-correlation value may be obtained on the time axis or may be obtained from the cross spectrum.

In the transmission system of multi-carrier communication, PAPR may be further improved by limiting the power of multi-carrier transmission in the almost periodic frequency arrangement.

In the transmission system of multi-carrier communication, the multi-carrier signal of the approximate periodic frequency arrangement is frequency-converted (up-converted) to the required radio frequency band, and in the reception system, the reception signal of the radio frequency band is down-converted to the base frequency band. A multi-carrier signal having an approximately periodic frequency arrangement of the above may be obtained.

In a multi-access communication system using a multi-carrier with an almost periodic frequency arrangement, the transmission power transmitted from each terminal may be controlled so that the reception level at the base station (server station) is substantially constant.

[2. Details of the embodiment]
[2.1 Determining Almost Periodic Frequency]
FIG. 1 shows a procedure for determining an almost periodic frequency arrangement, and FIG. 2 shows an almost periodic frequency arrangement generator (almost periodic frequency arrangement generation unit) 10. The almost periodic frequency arrangement generator 10 is composed of, for example, a computer having a processor and a memory. The computer constituting the almost periodic frequency arrangement generation device 10 executes the procedure shown in FIG. 1 by executing the computer program stored in the memory, and functions as the approximate periodic frequency arrangement generation device shown in FIG. The almost periodic frequency generator 10 may be mounted on the communication device, or may be configured as a device separate from the communication device.

The almost periodic frequency arrangement generation device 10 shown in FIG. 2 includes a prime group storage unit 11, a calculation / storage unit 12 of an approximate periodic frequency group, a calculation / storage unit 13 of a reference frequency arrangement, and a search / search of an approximate periodic frequency arrangement. It includes a storage unit 14. The prime number group storage unit 11 stores a large number (for example, 10 million) of prime numbers used for calculating the almost periodic frequency. The approximate periodic frequency group calculation / storage unit 13 calculates and stores the approximate periodic frequency using the prime numbers stored in the prime number group storage unit 11. The calculation / storage unit 13 of the reference frequency arrangement calculates and stores the reference frequency arrangement used for determining the almost periodic frequency arrangement. The search / storage unit 14 of the approximate periodic frequency arrangement searches for and selects an approximate periodic frequency close to the reference carrier frequency in the reference frequency arrangement from the approximate periodic frequency group, determines the approximate periodic frequency arrangement, and determines the approximate periodic frequency. Memorize the frequency arrangement.

Returning to FIG. 1, in order to determine the almost periodic frequency, first, the calculation / storage unit 12 of the approximate periodic frequency group calculates the approximate periodic frequency group (step S11). Almost periodic frequency group calculation / storage unit 12 calculates and stores the almost periodic frequency _fk according to the equation (almost periodic function) in step S11 of FIG. In the equation in step S11, n is any integer or real number, but can be, for example, 1.5, 2 or 3. Further, (mod 1) is a function for obtaining a fractional part of a real number.

Almost periodic functions are not limited to the format shown in FIG. For example, the equation (almost periodic function) in step S11 of FIG. 1 shows an example of obtaining from the nth root of a prime number in order to obtain the almost periodic frequency of an irrational number. th power may be a (e ^n), it may be obtained by irrational acceleration remainder calculation. To find the almost periodic frequency of a rational number, there are methods such as limiting the number of digits of the almost periodic frequency of an irrational number and finding it as a fraction of an integer.

Since prime numbers exist infinitely, almost periodic functions can be generated infinitely. FIG. 3A is a plot of the normalized frequencies (frequency in the range of 0 [Hz] to 1 [Hz]) obtained when n = 2 in the almost periodic function shown in FIG. 3 (b) is a plot of the normalized frequencies obtained when n = 1.5 as well. In FIG. 3, the horizontal axis represents the magnitude of the prime number and the vertical axis represents the normalized frequency. The black parts are plotted in FIGS. 3 (a) and 3 (b), and it can be seen from the prime numbers that a large number of frequencies are uniformly distributed over the entire range (0 to 1) of the normalized frequencies. ..

Further, in step 12, the reference frequency arrangement is calculated by the calculation / storage unit 13 of the reference frequency arrangement. FIG. 4 shows an example of the reference frequency arrangement. Similar to OFDM, the reference frequency arrangement has the frequency intervals Δf between carriers at equal intervals. When a plurality of reference carriers (plurality of reference carriers) are arranged in the range of the normalized frequency (0 to 1), the frequency interval Δf between the carriers is determined by the total number N of the reference carriers. That is, the frequency interval Δf = 1 / N. The total number N of the reference carriers is also a code multiplex number, and it is preferable that the total number N is a power of 2 in order to reduce the calculation load. In FIG. _4, C 1 -C _N indicates the reference carrier of the N. The frequency of the FIG. 1, Delta] f / 2 is a reference carrier (subchannel) C _1, C _N on both sides of the range of the normalized frequency, and the pass band width of the edge (normalized frequency is 0 or 1) It shows the difference.

Here, if the time length per code is ΔT, the frame time length of the almost periodic function may be signal-processed in units of NΔT according to the number of multiplexings N. The signal processing time length T = NΔT. Further, 1 / NΔT becomes the fundamental frequency, Δf = 1 / (NΔT), and the pass bandwidth BW becomes BW = 1 / ΔT [Hz] from N times Δf.

In step S13, the search / storage unit 14 for the almost periodic frequency arrangement searches for the almost periodic frequency used for the almost periodic frequency arrangement from the almost periodic frequency group obtained in step S12. In step S14, among the found almost periodic frequency, the closest of N almost periodic frequency is extracted in the reference carrier C ₁ -C _N of each frequency as a target, consisting of the extracted N number of almost periodic frequency Almost periodic frequency arrangement is determined.

Almost periodic frequency obtained from almost periodic function shown in FIG. 1, since the irrational number does not coincide with the frequency of the reference carrier C ₁ -C _N is a rational number. Therefore, the almost periodic frequency arrangement consisting of the searched N almost periodic frequencies is non-equidistant. However, since the frequency close to the reference carrier C ₁ -C _N equally spaced are selected generally equal intervals. Incidentally, almost periodic frequency, if it is rational does not coincide with the frequency of the reference carrier C ₁ -C _N, may be selected close to the frequency of the reference carrier C ₁ -C _N.

Figure 5 is almost periodic frequency selected, the reference carrier _C 1 -C _N normalized frequency standard deviation of how close the normalized frequency of the reference carrier _C 1 -C _N in frequency of the (standard deviation) Shown. In FIG. 5, the horizontal axis represents the total number of prime numbers used in step S11, and the vertical axis represents the normalized frequency standard deviation. As shown in FIG. 13, the larger the total number of primes, easier to select a frequency close to the reference carrier C ₁ -C _N, the frequency standard deviation is reduced. For example, when the total number of prime numbers exceeds 1 million, the frequency standard deviation becomes about 0.001 or less, and the interference between subcarriers can be reduced while maintaining the asynchrony of the almost periodic frequency arrangement. As shown in FIG. 5, as the total number of prime numbers increases, the standard deviation approaches zero and approaches the OFDM method.

[2.2 Communication device]
FIG. 6 shows a communication device 20 that communicates by a multicarrier having an almost periodic frequency arrangement. The communication device 20 includes a multi-carrier signal transmitter 30 and a multi-carrier signal receiver 40.

The transmitter 30 includes an input unit 31, a serial-parallel conversion unit 32, a subcarrier modulation unit 33, a multicarrier generation unit 34 having an almost periodic frequency arrangement, an output unit 35, and a synchronization signal generation unit 36. ing.

The input unit 32 receives an input of a transmission code (transmission data) from a signal processing device (not shown) included in the communication device 20, and if necessary, performs preprocessing that should be performed prior to multicarrier modulation. The serial-parallel conversion unit 32 converts the serial code (serial data) output from the input unit 32 into a parallel code (parallel data) having a parallel number corresponding to the multiple code length N. The parallel code having a code length N becomes the transmission code.

The subcarrier modulation unit 33 performs the almost periodic frequency multiplex modulation shown in FIG. 7. The subcarrier modulation unit 33 performs subcarrier modulation of the transmission code (d ₁ d ₂ d ₃ ... d _N-1 d _N ) having a code length N, and performs the subcarrier modulation of the code sequence (y ₁ y ₂ y ₃ .... The approximate periodic frequency arrangement multicarrier signal indicated by _{y N-1} y _{N) is output.} The subcarrier modulation unit 33 performs multicarrier modulation based on the multicarriers given by the multicarrier generation unit 34 having an almost periodic frequency arrangement. The multicarrier generation unit 34 having an almost periodic frequency arrangement may be configured to include the approximate frequency arrangement generation unit 10 shown in FIG. 2, or the almost periodic frequency determined by the approximate frequency arrangement generation unit 10 shown in FIG. The arrangement may be set to generate carriers with the set almost periodic frequency arrangement.

In output relationship shown in FIG. 7, the matrix having elements _{a k b k ~p k (1} ≦ k ≦ N), an N × N matrix. Further, in FIG. 7, ρ _dk is a prime number used to generate the k-th frequency in the almost periodic frequency arrangement having N carriers. Further, in FIG. 7, θ _k is an arbitrary real number and may be 0.

Incidentally, in the input-output relation shown in FIG. 7, although not explicitly defined elements _a k _{b k} other elements _{c k} ~p k, _A k included in the definition of the elements _a k _{b k,} the _{B k} , C _{k to} P _k . C _k to P _{k is} A k, the amplitude value of the k-th carrier in the same manner as _{B k.}

The subcarrier signal output from the subcarrier modulation unit 33 is given to the output unit 35, and is transmitted from the output unit 35 as an almost periodic subcarrier output signal (almost periodic frequency subcarrier composite signal) (radio propagation path, etc.). Is output to.

The serial-parallel conversion unit 33, the subcarrier modulation unit 33, and the output unit 35 operate based on the synchronization signal given by the synchronization signal generation unit 36.

The receiver 40 includes an input unit 41, a subcarrier demodulation unit 42, a frequency generation unit 43 having an almost periodic frequency arrangement, a parallel serial conversion unit 44, an output unit 45, and a synchronization signal generation unit 46. There is.

The input unit 41 receives the input of the received signal (almost periodic frequency subcarrier composite signal) and gives the received signal to the subcarrier demodulation unit 42. The subcarrier demodulation unit 42 obtains a cross-correlation value (complex correlation value) between the approximate period frequency used on the transmitting side of the received signal (approximately periodic frequency arrangement for demodulation; approximately periodic complex carrier wave) and the received signal. Perform demodulation. The frequency of the almost periodic frequency arrangement for demodulation is given by the frequency generation unit 43 of the almost periodic frequency arrangement. For the cross-correlation value of the signal, for example, the following "method of obtaining on the time axis" and "method of obtaining from the cross spectrum" can be adopted.

The signal output from the demodulation unit 42 is converted into serial data by the parallel serial conversion unit 44. This serial data is output as a demodulated code to a signal processing device (not shown) via the output unit 45.

The input unit 41, the subcarrier demodulation unit 42, the frequency generation unit 43 having an almost periodic frequency arrangement, and the parallel serial conversion unit 44 operate based on the synchronization signal given by the synchronization signal generation unit 46.

FIG. 8A shows an output unit 35 having a band limiting function. The output unit 35 includes an input processing circuit 351 that receives an input of an approximate periodic frequency subcarrier synthesis signal (time region signal) given from the modulation unit 33, an FFT processing circuit 352, a band limiting processing circuit 353, and an IFFT processing. It includes a circuit 354 and. The FFT processing circuit 352 converts the almost periodic frequency subcarrier synthesis signal, which is a time domain signal, into a frequency domain signal. The band limitation processing circuit 353 limits the frequency band of the signal and removes unnecessary frequency components. The IFFT processing circuit 354 returns the band-limited signal to the time axis region signal. Since the output unit 35 has the configuration shown in FIG. 8A, it is possible to limit the band for the almost periodic frequency subcarrier composite signal.

FIG. 8B shows an input unit 41 having a band limiting function. The input unit 41 includes an input processing circuit 411 that receives an input of an approximate periodic frequency subcarrier synthesis signal (time domain signal) that is a reception signal, an FFT processing circuit 412, a band limiting processing circuit 413, and an IFFT processing circuit 414. , Is equipped. The FFT processing circuit 412 converts the almost periodic frequency subcarrier synthesis signal, which is a time domain signal, into a frequency domain signal. The band limiting processing circuit 413 limits the band of the signal and removes unnecessary frequency components. The IFFT processing circuit 414 returns the band-limited signal to the time axis region signal. The band-limited signal is given to the subcarrier demodulation unit 42.

FIG. 9 has a multi-access communication system having a large number of terminals and base stations. The communication device 10 described above may be the base station shown in FIG. 9 or a terminal. The transmission power of the almost periodic multicarrier signal transmitted from each terminal may be controlled by the terminal based on the instruction from the base station, and the reception level at the base station may be substantially constant.

[2.3 PAPR]
FIG. 10 shows simulation values of PAPR for each of the OFDM type signal and the almost periodic frequency arrangement subcarrier synthesis signal. In FIG. 10, the horizontal axis represents the subcarrier multiply perfect number, and the vertical axis represents PAPR. As shown in FIG. 10, when the number of subcarrier multiplexing exceeds 512, it can be seen that the PAPR of the almost periodic frequency-arranged multicarrier signal tends to be lower than the PAPR of the OFDM signal and shows good characteristics. Further, it is considered that the PAPR tends to decrease when the number of multiplexings is 1000 or more because the error order of the Weyl series is O (1 / √N).

[2.4 PAPR compensation]
FIG. 11 shows a modified example of the receiver 30 included in the communication device 20. The receiver 30 of FIG. 11 is the receiver 30 shown in FIG. 6 with the PAPR compensation unit 37 added. The PAPR compensation unit 37 is provided between, for example, the subcarrier modulation unit 33 and the output unit 35. The PAPR compensator improves the PAPR of the almost periodic frequency subcarrier composite signal by limiting the peak value of the norm of the vector on the time axis of the almost periodic frequency subcarrier composite signal. The almost periodic frequency subcarrier composite signal with improved PAPR is output to a transmission line (radio propagation line, etc.) via the output unit 35.

FIG. 12 shows an example of a circuit configuration of the PAPR compensation unit 37. The PAPR compensation unit 37 includes an input unit 37a, a peak value detection unit 37b, an impulse new issue generation unit 37c, a complex synthesis unit 37d, and an output unit 37e.

The input unit 37a receives the input of the almost periodic frequency subcarrier composite signal. The peak value detection unit 37b detects the position and peak value of the peak of the almost periodic frequency subcarrier synthesis signal output from the input unit 37a on the time axis. When the detected peak value exceeds the specified value, the complex synthesis unit 37d peaks the signal generated by the impulse signal generation unit 37c with respect to the approximate periodic frequency subcarrier synthesis signal output from the input unit 37a. Complex synthesis is performed with the opposite polarity to the value. As a result, the peak is suppressed and the PAPR is reduced. The almost periodic frequency subcarrier composite signal in which the peak is suppressed is output via the output unit 37e. The signal generated by the impulse signal generation unit 37c is a reverse impulse signal corresponding to the difference between the detected peak value and the specified value. Further, it is clear that the PAPR compensation unit 37 shown in FIG. 12 can further improve PAPR by repeating the PAPR compensation process a plurality of times.

FIG. 13 shows the result of limiting the peak by the PAPR compensation unit 37 of FIG. FIG. 13 shows the case where the magnitude (peak limit level) of the inverse impulse signal is set to 2σ, 1.8σ, and 1.6σ, respectively, when the standard deviation of the peak in the almost periodic frequency subcarrier composite signal is σ. PAPR and PAPR without PAPR compensation are shown. In the case of the almost periodic frequency subcarrier composite signal without PARP compensation, the PAPR is about 8 to 9 [dB], whereas when the PAPR compensation is performed, the PAPR can be reduced. Further, the deeper the peak limit level, the more the PAPR can be reduced.

FIG. 13 shows the frequency standard deviation of each subcarrier constituting the approximate periodic frequency subcarrier composite signal, and when the frequency standard deviation is zero, it becomes OFDM. In the case of OFDM, PAPR is usually about 10 dB. As is clear from FIG. 13, the almost periodic frequency subcarrier signal can reduce PAPR more than OFDM even without PAPR compensation, and PAPR can be further reduced by performing PAPR compensation.

[2.4 Summary]
According to this embodiment, it is possible to reduce PAPR and improve the frequency utilization efficiency by reducing the intermodulation product in the transmission system by using the relationship of making the subcarrier complex frequencies asynchronous. Further, according to the present embodiment, it is possible to realize a super-multiplexing and super-multi-access communication system in which the transmission capacity can be increased by improving the efficiency of transmission power. The technology disclosed in this embodiment can be applied to a wide range of communication systems (including broadcasting systems) from audio / radio wave utilization systems to optical communications.

10 Almost periodic frequency arrangement generator 20 Communication device 30 Transmitter 33 Subcarrier modulation section 40 Receiver 42 Subcarrier demodulation section

Claims (6)

It ’s a communication method.
Including communication using multiple carriers
The frequency arrangement of the multicarriers is determined by selecting an almost periodic frequency close to the reference carrier frequency in the reference frequency arrangement in which the frequency intervals between the subcarriers are evenly spaced from the almost periodic frequency group based on the almost periodic function. A communication method that includes an almost periodic frequency arrangement. It ’s a communication method.
Including communication using multiple carriers
The multicarrier frequency arrangement includes an almost periodic frequency arrangement.
Almost periodic frequency arrangement is an arrangement in which the frequency intervals between subcarriers are almost periodic non-equal intervals based on an almost periodic function.
Communication method. The almost periodic frequency arrangement includes at least a first partial almost periodic frequency arrangement and a second partial almost periodic frequency arrangement other than the first partial almost periodic frequency arrangement.
The communication method according to claim 1 or 2, wherein the second partial periodic frequency arrangement is obtained by frequency-shifting the first partial general periodic frequency arrangement. The communication method according to any one of claims 1 to 3, wherein the frequency arrangement of the multi-carrier further includes a frequency arrangement in which the subcarriers are evenly spaced. It ’s a communication device,
A modulator that modulates a subcarrier in a multicarrier based on a transmission code is provided.
The frequency arrangement of the multicarriers is roughly determined by selecting an almost periodic frequency close to the reference carrier frequency in the reference frequency arrangement in which the frequency intervals between carriers are evenly spaced from the almost periodic frequency group based on the almost periodic function. A communicator that includes periodic frequency arrangements. It ’s a communication device,
A modulator that modulates a subcarrier in a multicarrier based on a transmission code is provided.
The multicarrier frequency arrangement includes an almost periodic frequency arrangement.
Almost periodic frequency arrangement is an arrangement in which the frequency intervals between subcarriers are almost periodic non-equal intervals based on an almost periodic function.
Communication device.

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