Wireless communication method, wireless communication system, and transmitting device

Abstract

This wireless communication method includes: a phase shift amount determination process for determining a phase shift amount for each sub-carrier of transmission data; a modulation process for modulating the transmission data and also further shifting the phase in accordance with the phase shift amount for each sub-carrier; and a precoding process for precoding the transmission data obtained after the modulation process. The transmission data obtained after the precoding process is transmitted from a transmission device to a reception device. A plurality of types of phase shift patterns prepared in advance define respective phase shifts which are different from each other. The phase shift amount determination process selects, from the plurality of types of phase shift patterns, one pattern that minimizes the PAPR of the transmission data obtained after the precoding process, or one pattern that maximizes the data reception quality at the reception device, and determines the phase shift amount for each sub-carrier according to the selected phase shift pattern.

Description

[Technical Field]

[0001] The present invention relates to a wireless communication technology, and more particularly to a wireless communication technology in which a transmitting side performs precoding on transmission data. [Background technology]

[0002] In wireless communication, the transmitter may perform precoding on the transmitted data. For example, when wideband transmission is performed in a frequency-selective fading environment, precoding is used to perform channel equalization. As another example, in a MIMO (Multiple-Input Multiple-Output) system, precoding is used to separate streams.

[0003] When precoding is performed on the transmitting side, the PAPR (Peak to Average Power Ratio) increases due to signal superposition. The transmission signal is amplified by a power amplifier before being transmitted from the antenna, but when a signal with a high PAPR is input to the power amplifier, it may be affected by the nonlinear characteristics of the power amplifier and cause nonlinear distortion. Nonlinear distortion of the transmission signal may result in communication with many errors.

[0004] Non-Patent Document 1 discloses a technique for reducing the PAPR in a wideband single-carrier MIMO system. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Kuriyama et al., "PAPR Reduction on Wideband Single-Carrier MIMO Systems with Variable Tap-Length FIR Beamforming," IEICE Communications Society Conference, B-5-70, September 2021. Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, when a transmitter performs precoding on transmission data in wireless communication, the PAPR increases.

[0007] An object of the present invention is to provide a technique capable of reducing the PAPR when a transmitting side performs precoding on transmission data in wireless communication. [Means for solving the problem]

[0008] The first aspect relates to a wireless communication method for performing wireless communication between a transmitting device and a receiving device. The wireless communication method is a phase shift amount determination process for determining a phase shift amount for each subcarrier of the transmission data; a modulation process for modulating transmission data and further shifting the phase for each subcarrier according to the phase shift amount; a precoding process for performing precoding on the transmission data after the modulation process; A transmission process of transmitting the transmission data after the precoding process from the transmitting device to the receiving device. Includes: The plurality of types of phase shift patterns prepared in advance define different phase shift amounts. The phase shift amount determination process is as follows: Selecting one of the phase shift patterns that minimizes the PAPR of the transmission data after precoding processing or that maximizes the reception quality of the transmission data at the receiving device; determining a phase shift amount for each subcarrier according to the selected phase shift pattern; Includes.

[0009] The second aspect relates to a wireless communication system. The wireless communication system includes a transmitting device and a receiving device. The transmitting device a phase shift amount determination process for determining a phase shift amount for each subcarrier of the transmission data; a modulation process for modulating transmission data and further shifting the phase for each subcarrier according to the phase shift amount; a precoding process for performing precoding on the transmission data after the modulation process; A transmission process of transmitting the transmission data after the precoding process to the receiving device. is configured to execute The plurality of types of phase shift patterns prepared in advance define different phase shift amounts. The phase shift amount determination process is as follows: Selecting one of the phase shift patterns that minimizes the PAPR of the transmission data after precoding processing or that maximizes the reception quality of the transmission data at the receiving device; determining a phase shift amount for each subcarrier according to the selected phase shift pattern; Includes.

[0010] The third aspect relates to a transmitting device that performs wireless communication with a receiving device. The transmitting device a phase shift amount determination unit that determines a phase shift amount for each subcarrier of the transmission data; a modulation unit that modulates transmission data and further shifts the phase for each subcarrier according to the phase shift amount; a precoding unit that performs precoding on the transmission data after modulation processing; a transmitting unit that transmits the pre-encoded transmission data to a receiving device; Equipped with. The plurality of types of phase shift patterns prepared in advance define different phase shift amounts. The phase shift amount determination unit selects one of the multiple types of phase shift patterns that minimizes the PAPR of the transmission data after precoding processing, or that maximizes the reception quality of the transmission data at the receiving device. Then, the phase shift amount determination unit determines the phase shift amount for each subcarrier in accordance with the selected phase shift pattern. [Effects of the Invention]

[0011] According to the present invention, it is possible to reduce the PAPR when a transmitting side performs precoding on transmission data in wireless communication. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a conceptual diagram illustrating a configuration of a wireless communication system according to an embodiment. [Figure 2] FIG. 1 is a block diagram illustrating an example of a basic configuration of a transmitting device that performs precoding. [Figure 3] 4A and 4B are conceptual diagrams for explaining the amplification characteristics of an amplifier section. [Figure 4] FIG. 10 is a conceptual diagram for explaining constellation distortion. [Figure 5] FIG. 1 is a conceptual diagram for explaining the basics of phase shifting according to an embodiment. [Figure 6] FIG. 1 is a conceptual diagram for explaining an overview of a phase shift according to an embodiment. [Figure 7] 5A and 5B are conceptual diagrams for explaining an example of a phase shift pattern according to the embodiment. [Figure 8] FIG. 10 is a conceptual diagram for explaining a signal addition process according to the embodiment. [Figure 9] 10A and 10B are conceptual diagrams for explaining the effect of a phase shift according to the embodiment. [Figure 10] 10 is a flowchart summarizing a process performed by a transmitting device according to an embodiment. [Figure 11] 1 is a block diagram illustrating a first exemplary configuration of a transmission device according to an embodiment. [Figure 12] FIG. 10 is a block diagram showing a second exemplary configuration of a transmission device according to an embodiment. [Figure 13] FIG. 1 is a block diagram illustrating a configuration example of a receiving device according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of the present invention will be described with reference to the accompanying drawings.

[0014] 1. Overview of wireless communication systems 1 is a conceptual diagram showing a schematic configuration of a wireless communication system 1 according to this embodiment. The wireless communication system 1 includes a transmitting device 100 and a receiving device 200. The transmitting device 100 and the receiving device 200 perform wireless communication. The wireless communication system 1 may be a MIMO (Multiple-Input Multiple-Output) system, a SISO (Single-Input Single-Output) system, or any other system. The wireless communication system 1 may perform single-carrier transmission, or may perform multi-carrier transmission based on OFDM (Orthogonal Frequency Division Multiplexing) or the like.

[0015] The transmitting device 100 performs precoding on the transmission data before transmitting the transmission data to the receiving device 200. Precoding is a well-known technique. For example, when wideband transmission is performed in a frequency selective fading environment, channel equalization is performed by precoding. As another example, in a MIMO system, stream separation is performed by precoding.

[0016] 2 is a block diagram showing an example of a basic configuration of a transmitting apparatus 100 that performs precoding. The transmitting apparatus 100 includes a modulating section 110, a precoding section 120, a D / A converting section 130, and an amplifying section 140.

[0017] The modulation unit 110 receives transmission data (transmission signal) TD0 transmitted from the transmitting device 100 to the receiving device 200. The modulation unit 110 performs "modulation processing" to modulate the transmission data TD0 using a predetermined modulation method. Examples of the predetermined modulation method include QAM (Quadrature Amplitude Modulation) and QPSK (Quadrature Phase Shift Keying). The modulation unit 110 outputs transmission data TD1 after the modulation processing.

[0018] The precoding unit 120 receives transmission data TD1 after modulation processing. The precoding unit 120 performs "precoding processing" to precode the transmission data TD1. There are various known examples of precoding weights (precoding matrices) used in the precoding processing. In this embodiment, the precoding weights are not particularly limited. The precoding unit 120 outputs transmission data TD2 after precoding processing.

[0019] The D / A conversion unit 130 receives the pre-coded transmission data TD2, performs D / A conversion on the transmission data TD2, and outputs transmission data TD3.

[0020] The amplifier 140 receives the D / A converted transmission data TD3. The amplifier 140 includes a power amplifier and performs an "amplification process" to amplify the transmission data TD3.

[0021] Furthermore, the amplifier 140 performs a "transmission process" of transmitting the amplified transmission data (transmission signal) TD4 via an antenna to the receiving device 200. The amplifier 140 also functions as a "transmitter" that performs the transmission process.

[0022] FIG. 3 is a conceptual diagram illustrating the amplification characteristics of the amplifier 140. The horizontal axis represents input signal power, and the vertical axis represents output signal power. As shown in FIG. 3, the amplification characteristics include not only a linear region but also a nonlinear region, and the higher the input signal power, the stronger the influence of the nonlinear characteristics. Even if the average power is included in the linear region, an input signal with a high PAPR (Peak to Average Power Ratio) is affected by the nonlinear characteristics. As a result, there is a risk of distortion of the constellation of the transmission data.

[0023] Figure 4 is a conceptual diagram for explaining distortion of the constellation of transmission data. Here, as an example, the constellation of transmission data in the case of 64QAM is shown. In the linear domain, no distortion occurs in the constellation. However, in the nonlinear domain, distortion occurs in the constellation.

[0024] As described above, in this embodiment, the transmitting device 100 (precoding unit 120) performs precoding on transmission data. Precoding involving signal superposition tends to increase the PAPR. Therefore, when transmission data (transmission signal) with a high PAPR is input to the amplifying unit 140, it may be affected by nonlinear characteristics and may cause nonlinear distortion. If nonlinear distortion occurs in the transmission data, it may result in communication with many errors.

[0025] Therefore, this embodiment provides a technique that can reduce the PAPR when transmitting apparatus 100 performs precoding on transmission data. In this embodiment, in order to reduce the PAPR, a "phase shift" described below is introduced.

[0026] 2. PAPR reduction using phase shift 5 is a conceptual diagram for explaining the basics of phase shifting according to this embodiment. Here, as an example, a case where the modulation method is 64QAM is shown. However, the modulation method is not limited to 64QAM.

[0027] The transmitting device 100 (modulation unit 110) performs modulation processing to modulate the transmission data using a predetermined modulation method. In this modulation processing, the transmitting device 100 not only modulates the transmission data using the predetermined modulation method, but also applies a phase shift to the transmission data. The amount of phase shift is θs. In other words, in the modulation processing, the transmitting device 100 modulates the transmission data using the predetermined modulation method, and also further shifts the phase of the transmission data in accordance with the phase shift amount θs.

[0028] 6 is a conceptual diagram for explaining an overview of phase shifting according to this embodiment. Transmitting apparatus 100 performs multicarrier transmission based on OFDM or the like. According to this embodiment, a phase shift amount θs is determined for each subcarrier of transmission data, and phase shifting is performed. That is, a phase shift amount θs is determined separately for each subcarrier in the frequency direction, and phase shifting is performed for each subcarrier according to the phase shift amount θs.

[0029] Furthermore, according to this embodiment, a "phase shift pattern PAT" that defines the phase shift amount θs for each subcarrier is prepared in advance. The phase shift pattern PAT defines the phase shift amount θs for each subcarrier so that the phase shift amount θs differs between two or more subcarriers.

[0030] FIG. 7 is a conceptual diagram for explaining an example of a phase shift pattern PAT according to this embodiment. Phase shift processing is performed in predetermined data units (e.g., frame, slot). Transmission data in the frequency domain is obtained by FFT (Fast Fourier Transform). The phase shift amount θs is determined separately for each subcarrier. Specifically, the phase shift amount θs of each subcarrier Si (i=1, 2, 3, . . .) is expressed by the following equation (1):

[0031] Equation (1): θs = (i-1)π / N

[0032] Here, the parameter N is an integer other than 0. In this way, in the example shown in Fig. 7, the phase shift amount θs differs by a constant amount (π / N) between successive subcarriers Si.

[0033] Furthermore, according to this embodiment, multiple types of phase shift patterns PAT are prepared in advance. The multiple types of phase shift patterns PAT each define a different phase shift amount θs. For example, in the example shown in FIG. 7, the multiple types of phase shift patterns PAT each define a phase shift amount θs based on a different parameter N (e.g., N=4, 6, 8, etc.). Note that different indexes are assigned to the multiple types of phase shift patterns PAT.

[0034] The transmitting device 100 selects one from among a plurality of types of phase shift patterns PAT. For example, the transmitting device 100 performs modulation processing using each of the plurality of types of phase shift patterns PAT, and then performs subsequent processing. Then, the transmitting device 100 calculates the PAPR of the transmission data after precoding processing by the precoding unit 120, and selects one from among the plurality of types of phase shift patterns PAT that minimizes the PAPR. As another example, the transmitting device 100 may obtain information on reception quality (e.g., BER (Bit Error Rate)) from the receiving device 200, and select one from among the plurality of types of phase shift patterns PAT that maximizes the reception quality.

[0035] Then, the transmitting device 100 determines the phase shift amount θs for each subcarrier of the transmission data in accordance with the selected phase shift pattern PAT, and then performs modulation processing in accordance with the determined phase shift amount θs, and then performs subsequent processing.

[0036] 8 is a conceptual diagram for explaining the "signal addition process" according to this embodiment. The transmitting device 100 adds an index signal (control signal) indicating one selected phase shift pattern PAT to the transmission data. More specifically, the transmitting device 100 adds the index signal to the beginning or end of a predetermined data unit (e.g., frame, slot).

[0037] The receiving device 200 receives the transmission data transmitted from the transmitting device 100 as received data. The receiving device 200 can recognize the phase shift pattern PAT applied to a predetermined data unit based on an index signal added to the received data. The receiving device 200 then demodulates the received data taking into account the phase shift pattern PAT applied to the data unit. That is, when demodulating the received data, the receiving device 200 shifts back the phase by the phase shift amount θs for each subcarrier of the received data.

[0038] FIG. 9 is a conceptual diagram for explaining the effect of phase shift according to this embodiment. As shown in FIG. 9, phase shift causes the distribution of symbol sequences in a constellation (symbol distribution) to approach a circular shape. Because the symbol phase at which peak power occurs is shifted, the peak power decreases when signals are superimposed by precoding. Furthermore, because the transition to a symbol at a point-symmetric position does not pass through a zero point, the average power increases compared to when phase shift is not performed. In this way, by performing phase shift during modulation processing of transmission data, it is possible to reduce the PAPR.

[0039] FIG. 10 is a flowchart showing an outline of the processing performed by transmitting apparatus 100 according to the present embodiment.

[0040] In step S110, the transmitting device 100 performs a "phase shift amount determination process." That is, the transmitting device 100 determines a phase shift amount θs for each subcarrier of the transmission data. More specifically, the transmitting device 100 selects one from among multiple types of phase shift patterns PAT prepared in advance. For example, the transmitting device 100 selects one from among multiple types of phase shift patterns PAT that minimizes the PAPR of the transmission data after precoding processing. As another example, the transmitting device 100 may select one from among multiple types of phase shift patterns PAT that maximizes the reception quality of the transmission data at the receiving device 200. Then, the transmitting device 100 determines a phase shift amount θs for each subcarrier according to the selected phase shift pattern PAT.

[0041] In step S120, the transmitting device 100 performs a "modulation process" on the transmission data. More specifically, the transmitting device 100 modulates the transmission data using a predetermined modulation method, and further shifts the phase for each subcarrier in accordance with the phase shift amount θs.

[0042] In step S130, the transmitting device 100 performs a "signal addition process" on the transmission data. More specifically, the transmitting device 100 adds an index signal (control signal) indicating the selected one phase shift pattern PAT to the transmission data.

[0043] In step S140, the transmitting device 100 performs "precoding processing" on the transmission data. More specifically, the transmitting device 100 performs precoding on the transmission data after modulation processing.

[0044] In step S150, the transmitting device 100 performs a "transmission process" of transmitting the transmission data after the precoding process from the transmitting device to the receiving device.

[0045] During communication, the transmitting device 100 may update the phase shift pattern PAT as appropriate. When updating, the transmitting device 100 may reconsider all types of phase shift patterns PAT and select one from all types of phase shift patterns PAT. Alternatively, the transmitting device 100 may reconsider only a certain number of phase shift patterns PAT that were relatively excellent last time and select one from the certain number of phase shift patterns PAT.

[0046] As described above, according to this embodiment, by applying a phase shift to transmission data, it is possible to reduce the PAPR when precoding is performed.

[0047] 3.Configuration example An example of the configuration of the transmitting device 100 and the receiving device 200 will be described below.

[0048] 3-1. Example of transmitter configuration 3-1-1. First configuration example 11 is a block diagram showing a first exemplary configuration of the transmitting device 100. The transmitting device 100 includes a modulating unit 110A, a precoding unit 120, a D / A converting unit 130, an amplifying unit 140, a phase shift amount determining unit 150, a signal adding unit 160, and a PAPR calculating unit 170. The modulating unit 110A has a phase shift function in addition to the function of the modulating unit 110 shown in FIG. 2. The precoding unit 120, the D / A converting unit 130, and the amplifying unit 140 are the same as those shown in FIG. 2.

[0049] The phase shift amount determination unit 150 performs a “phase shift amount determination process.” That is, the phase shift amount determination unit 150 determines the phase shift amount θs for each subcarrier of the transmission data TD0.

[0050] More specifically, the phase shift amount determination unit 150 holds information on a plurality of types of phase shift patterns PAT prepared in advance. Each of the plurality of types of phase shift patterns PAT defines a different phase shift amount θs. The phase shift amount determination unit 150 provisionally selects one of the plurality of types of phase shift patterns PAT in order. The phase shift amount determination unit 150 notifies the modulation unit 110A of the phase shift amount θs for each subcarrier defined in the provisionally selected phase shift pattern PAT.

[0051] The modulation unit 110A receives information on the phase shift amount θs for each subcarrier from the phase shift amount determination unit 150. In the modulation process, the modulation unit 110A modulates the transmission data TD0 using a predetermined modulation method, and further shifts the phase for each subcarrier in accordance with the phase shift amount θs (see FIG. 7). The modulation unit 110A outputs the modulated transmission data TD1.

[0052] The precoding unit 120 receives the modulated transmission data TD1, performs precoding on the transmission data TD1, and outputs transmission data TD2.

[0053] The PAPR calculation unit 170 receives the transmission data TD2 after precoding processing. The PAPR calculation unit 170 calculates the PAPR of the transmission data TD2 in a predetermined data unit according to a predetermined calculation formula. The PAPR calculation unit 170 outputs information about the calculated PAPR to the phase shift amount determination unit 150.

[0054] The phase shift amount determination unit 150 acquires information on PAPR for each of the multiple types of phase shift patterns PAT. Then, the phase shift amount determination unit 150 selects one of the multiple types of phase shift patterns PAT that minimizes the PAPR. The phase shift amount determination unit 150 determines the phase shift amount θs for each subcarrier according to the selected phase shift pattern PAT. Then, the phase shift amount determination unit 150 notifies the modulation unit 110A of the determined phase shift amount θs for each subcarrier. Thereafter, the modulation unit 110A performs modulation processing using the phase shift amount θs notified by the phase shift amount determination unit 150.

[0055] The signal adding unit 160 receives information on one phase shift pattern PAT selected by the phase shift amount determining unit 150. Furthermore, the signal adding unit 160 generates an index signal (control signal) indicating the selected one phase shift pattern PAT. Then, the signal adding unit 160 performs a "signal adding process" to add the index signal to the transmission data TD1 (see FIG. 8). More specifically, the signal adding unit 160 adds the index signal to the beginning or end of a predetermined data unit (e.g., frame, slot). Note that no phase shift is performed on the index signal.

[0056] 3-1-2. Second configuration example 12 is a block diagram showing a second configuration example of the transmitting device 100. Descriptions that overlap with the first configuration example shown in FIG.

[0057] In the second configuration example, the transmitting device 100 includes a reception quality information acquisition unit 180 instead of the PAPR calculation unit 170. The reception quality information acquisition unit 180 acquires information on the reception quality (e.g., BER) of the transmission data from the receiving device 200. The reception quality information acquisition unit 180 outputs the information on the reception quality to the phase shift amount determination unit 150.

[0058] The phase shift amount determination unit 150 acquires information on reception quality for each of multiple types of phase shift patterns PAT. Then, the phase shift amount determination unit 150 selects one of the multiple types of phase shift patterns PAT that provides the highest reception quality. The phase shift amount determination unit 150 determines the phase shift amount θs for each subcarrier according to the selected phase shift pattern PAT. Then, the phase shift amount determination unit 150 notifies the modulation unit 110A of the determined phase shift amount θs for each subcarrier. Thereafter, the modulation unit 110A performs modulation processing using the phase shift amount θs notified by the phase shift amount determination unit 150.

[0059] 3-1-3. Hardware configuration example The transmitting device 100 includes one or more processors (hereinafter simply referred to as "processors") and one or more storage devices (hereinafter simply referred to as "storage devices"). For example, the processor includes a CPU (Central Processing Unit). The storage devices store various information required for processing by the processor. Examples of storage devices include volatile memory, non-volatile memory, HDD (Hard Disk Drive), SSD (Solid State Drive), etc.

[0060] The processor may execute a control program, which is a computer program. The control program may be stored in a storage device. The control program may be recorded on a computer-readable recording medium. The processor's functions are realized by executing the control program.

[0061] The storage device stores information on a plurality of types of phase shift patterns PAT prepared in advance. The processor and the storage device cooperate to realize functions such as a modulation unit 110A, a precoding unit 120, a phase shift amount determination unit 150, a signal addition unit 160, a PAPR calculation unit 170, and a reception quality information acquisition unit 180.

[0062] 3-2. Example of receiving device configuration 13 is a block diagram showing an example of the configuration of the receiving device 200. The receiving device 200 includes an amplifying section 210, an A / D converting section 220, and a demodulating section 230.

[0063] The receiving device 200 receives the transmission data transmitted from the transmitting device 100 as received data (received signal) RD0. The amplifier 210 amplifies the received data RD0 and outputs received data RD1. The A / D converter 220 A / D converts the received data RD1 and outputs received data RD2.

[0064] The demodulation unit 230 performs a "demodulation process" to demodulate the received data RD2. At this time, the demodulation unit 230 demodulates the received data RD2 taking into account the amount of phase shift θs.

[0065] More specifically, the demodulation unit 230 includes a phase shift pattern acquisition unit 240. The phase shift pattern acquisition unit 240 holds information on multiple types of phase shift patterns PAT prepared in advance. An index signal indicating one phase shift pattern PAT applied to transmission data of a predetermined data unit (e.g., frame, slot) is also added to the received data RD2. Based on the index signal, the phase shift pattern acquisition unit 240 recognizes the phase shift pattern PAT applied to the transmission data of the predetermined data unit. The phase shift pattern acquisition unit 240 then acquires the phase shift amount θs for each subcarrier defined by the recognized phase shift pattern PAT. The demodulation unit 230 demodulates the received data RD2 using a predetermined demodulation method and shifts the phase back by the phase shift amount θs for each subcarrier.

[0066] The receiving device 200 includes one or more processors (hereinafter simply referred to as "processors") and one or more storage devices (hereinafter simply referred to as "storage devices"). The processor may execute a control program, which is a computer program. The control program is stored in the storage device. The control program may be recorded on a computer-readable recording medium. The processor executes the control program to realize its functions. The storage device stores information on multiple types of phase shift patterns PAT that are prepared in advance. The processor and the storage device cooperate to realize functions such as a demodulation unit 230 and a phase shift pattern acquisition unit 240. [Explanation of symbols]

[0067] 1. Wireless communication systems 100 Transmitting device 110,110A Modulation section 120 Precoding section 130 D / A conversion section 140 Amplification Unit 150 Phase shift amount determination unit 160 Signal Addition Unit 170 PAPR calculation section 180 Reception quality information acquisition unit 200 receiving device 210 Amplification section 220 A / D conversion section 230 Demodulation section 240 Phase shift pattern acquisition unit PAT Phase Shift Pattern

Claims

1. A wireless communication method for performing wireless communication between a transmitting device and a receiving device, a phase shift amount determination process for determining a phase shift amount for each subcarrier of the transmission data; a modulation process of modulating the transmission data and further shifting the phase for each subcarrier according to the phase shift amount; a precoding process for performing precoding on the transmission data after the modulation process; a transmission process of transmitting the transmission data after the precoding process from the transmitting device to the receiving device; Including, a plurality of types of phase shift patterns prepared in advance each define a different phase shift amount; The phase shift amount determination process includes: Selecting one of the phase shift patterns that minimizes a PAPR (Peak to Average Power Ratio) of the transmission data after the precoding process, or one that maximizes reception quality of the transmission data in the receiving device, from the plurality of types of phase shift patterns; determining the phase shift amount for each subcarrier according to the selected phase shift pattern; Including, the wireless communication method further includes a signal addition process of adding an index signal indicating the selected phase shift pattern to the transmission data; the phase shift amount determination process and the signal addition process are performed in predetermined data units, such as frames or slots; The signal addition process adds the index signal to the beginning or end of the predetermined data unit. Wireless communication method.

2. 2. The wireless communication method according to claim 1, The phase shift amount differs between two or more subcarriers of the transmission data. Wireless communication method.

3. 3. The wireless communication method according to claim 2, The phase shift amounts differ by a constant amount between the two or more subcarriers of the transmission data. Wireless communication method.

4. 4. A wireless communication method according to claim 1, further comprising: a process of receiving the transmission data transmitted from the transmitting device as reception data in the receiving device; a demodulation process for demodulating the received data based on the selected phase shift pattern indicated by the index signal; Further includes Wireless communication method.

5. a transmitting device; Receiving device and Equipped with The transmitting device a phase shift amount determination process for determining a phase shift amount for each subcarrier of the transmission data; a modulation process of modulating the transmission data and further shifting the phase for each subcarrier according to the phase shift amount; a precoding process for performing precoding on the transmission data after the modulation process; a transmission process of transmitting the transmission data after the precoding process to the receiving device; Run a plurality of types of phase shift patterns prepared in advance each define a different phase shift amount; The phase shift amount determination process includes: Selecting one of the phase shift patterns that minimizes a PAPR (Peak to Average Power Ratio) of the transmission data after the precoding process, or one that maximizes reception quality of the transmission data in the receiving device, from the plurality of types of phase shift patterns; determining the phase shift amount for each subcarrier according to the selected phase shift pattern; Including, the transmitting device further performs a signal addition process of adding an index signal indicating the selected phase shift pattern to the transmission data; the phase shift amount determination process and the signal addition process are performed in predetermined data units, such as frames or slots; The signal addition process adds the index signal to the beginning or end of the predetermined data unit. Wireless communication system.

6. 6. The wireless communication system according to claim 5, The receiving device receiving the transmission data transmitted from the transmitting device as reception data; demodulating the received data based on the selected phase shift pattern indicated by the index signal; Wireless communication system.

7. A transmitting device that wirelessly communicates with a receiving device, a phase shift amount determination unit that determines a phase shift amount for each subcarrier of the transmission data; a modulation unit that modulates the transmission data and further shifts the phase for each subcarrier according to the phase shift amount; a precoding unit that performs precoding on the modulated transmission data; a transmitting unit that transmits the precoded transmission data to the receiving device; Equipped with a plurality of types of phase shift patterns prepared in advance each define a different phase shift amount; The phase shift amount determination unit Select one of the phase shift patterns that minimizes a PAPR (Peak to Average Power Ratio) of the transmission data after the precoding, or select one that maximizes reception quality of the transmission data in the receiving device, from the plurality of types of phase shift patterns; determining the phase shift amount for each of the subcarriers according to the selected phase shift pattern; the transmitting device further includes a signal adding unit that adds an index signal indicating the selected phase shift pattern to the transmission data; The processing by the phase shift amount determination unit and the signal addition unit is performed in predetermined data units, such as frames or slots, The signal adding unit adds the index signal to the beginning or end of the predetermined data unit. Transmitting device.

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