Wireless communication method, wireless communication system, and transmitting device

Abstract

This wireless communication method comprises phase shift amount determination processing of determining a phase shift amount for each stream of transmission data, modulation processing of modulating the transmission data and shifting the phase further for each stream according to the phase shift amount, and precoding processing of precoding the transmission data subjected to the modulation processing. A transmission device transmits the transmission data subjected to the precoding processing to a reception device. A plurality of types of phase shift patterns prepared in advance define different phase shift amounts, respectively. The phase shift amount determination processing involves selecting, from among the plurality of types of phase shift patterns, a phase shift pattern that minimizes the PAPR of the transmission data subjected to the precoding processing or a phase shift pattern that maximizes the received data quality in the reception device, and determining the phase shift amount for each stream 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, a transmitter may perform precoding on transmission data. For example, when performing wideband transmission in a frequency selective fading environment, channel equalization is performed by precoding. As another example, in a multiple-input multiple-output (MIMO) system, stream separation is performed by precoding.

[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. If nonlinear distortion occurs in the transmission signal, it 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 transmitting side 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 stream of transmission data; a modulation process for modulating the transmission data and further shifting the phase according to a phase shift amount for each stream; 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 multiple 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 multiple phase shift patterns that minimizes the PAPR of the transmission data after the precoding process, or selects one of the multiple phase shift patterns that maximizes the reception quality of the transmission data at the receiving device; determining a phase shift amount for each stream 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 stream of transmission data; a modulation process for modulating the transmission data and further shifting the phase according to a phase shift amount for each stream; 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 a receiving device. The apparatus is configured to execute the following steps: The multiple 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 multiple phase shift patterns that minimizes the PAPR of the transmission data after the precoding process, or selects one of the multiple phase shift patterns that maximizes the reception quality of the transmission data at the receiving device; determining a phase shift amount for each stream 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 stream of transmission data; a modulation unit that modulates transmission data and further shifts the phase of each stream according to a phase shift amount; A precoding unit that performs precoding on the transmission data after modulation processing; A transmitting unit that transmits the transmission data after the precoding process to a receiving device; Equipped with. The multiple types of phase shift patterns prepared in advance define different phase shift amounts. The phase shift amount determination unit selects, from among a plurality of types of phase shift patterns, one that minimizes the PAPR of transmission data after precoding processing, or one that maximizes the reception quality of the transmission data in the receiving device. Then, the phase shift amount determination unit determines the amount of phase shift for each stream in accordance with the selected phase shift pattern. Effect 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 description of the drawings]

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

[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 illustrating a schematic configuration of a wireless communication system 1 according to the present 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 multiple-input multiple-output (MIMO) system, a single-input single-output (SISO) system, or another system. The wireless communication system 1 may perform single-carrier transmission, or may perform multi-carrier transmission based on orthogonal frequency division multiplexing (OFDM) 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 performing wideband transmission 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 device 100 that performs precoding. The transmitting device 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 the transmission data TD1 after the modulation process. The precoding unit 120 performs a "precoding process" for performing precoding on the transmission data TD1. There are various examples of precoding weights (precoding matrices) used in the precoding process. In this embodiment, the precoding weights are not particularly limited. The precoding unit 120 outputs the transmission data TD2 after the precoding process.

[0019] The D / A conversion unit 130 receives the transmission data TD2 after the precoding process. The D / A conversion unit 130 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 to the receiving device 200 via an antenna. The amplifier 140 also functions as a "transmitter" that performs the transmission process.

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

[0023] FIG. 4 is a conceptual diagram for explaining the distortion of the constellation of the transmission data. Here, as an example, the constellation of the transmission data in the case of 64QAM is shown. In the linear domain, the constellation is not distorted. However, in the nonlinear domain, the constellation is distorted.

[0024] As described above, in this embodiment, the transmitting device 100 (precoding unit 120) performs precoding on the transmission data. Precoding involving signal superposition tends to increase the PAPR. Therefore, when transmission data (transmission signal) with high PAPR is input to the amplifier 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 capable of reducing 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 the phase shift according to the present 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 a modulation process to modulate the transmission data using a predetermined modulation method. In this modulation process, the transmitting device 100 not only modulates the transmission data using the predetermined modulation method, but also adds a phase shift to the transmission data. The amount of phase shift is θs. In other words, in the modulation process, the transmitting device 100 modulates the transmission data using the predetermined modulation method, and further shifts the phase of the transmission data according to the phase shift amount θs.

[0028] 6 is a conceptual diagram for explaining an outline of the phase shift according to this embodiment. According to this embodiment, the transmitting device 100 transmits transmission data using a plurality of streams. At that time, the transmitting device 100 determines a phase shift amount θs for each stream of the transmission data and performs phase shift. That is, the phase shift amount θs is determined separately in the stream direction, and the phase shift is performed for each stream according to the phase shift amount θs.

[0029] According to this embodiment, a "phase shift pattern PAT" that defines a phase shift amount θs for each stream is prepared in advance. The phase shift pattern PAT defines the phase shift amount θs for each stream such that the phase shift amount θs differs between two or more streams.

[0030] FIG. 7 is a conceptual diagram for explaining an example of a phase shift pattern PAT according to this embodiment. The phase shift process is performed in a predetermined data unit (e.g., frame, slot). The phase shift amount θs is determined separately for each stream. Specifically, the phase shift amount θs of the i-th stream 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. Thus, in the example shown in Fig. 7, the phase shift amount θs differs by a constant amount (π / N) between the streams in sequence. Note that in the example shown in Fig. 7, the first stream S1 is the reference stream, and no phase shift is performed on the first stream S1.

[0033] Furthermore, according to this embodiment, a plurality of types of phase shift patterns PAT are prepared in advance. The plurality of types of phase shift patterns PAT each define a different phase shift amount θs. For example, in the example shown in Fig. 7, the plurality of 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,...). Note that a different index is given to each of the plurality of 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 further performs subsequent processing. Then, the transmitting device 100 calculates the PAPR of the transmission data after the precoding processing by the precoding unit 120, and selects one from among the plurality of types of phase shift patterns PAT that provides the minimum 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 provides the highest reception quality.

[0035] Then, the transmitting device 100 determines the amount of phase shift θs for each stream of the transmission data according to the selected one phase shift pattern PAT. After that, the transmitting device 100 performs modulation processing according to the determined amount of phase shift θs, and further performs subsequent processing.

[0036] Fig. 8 is a conceptual diagram for explaining "signal addition processing" according to this embodiment. The transmitting device 100 adds an index signal (control signal) indicating one selected phase shift pattern PAT to each stream of transmission data. More specifically, the transmitting device 100 adds an index signal to the beginning or end of a predetermined data unit (e.g., frame, slot). An index signal does not need to be added to a reference stream in which no phase shift is performed (first stream S1 in the examples shown in Figs. 7 and 8).

[0037] The receiving device 200 receives the transmission data transmitted from the transmitting device 100 as the 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 returns the phase by the phase shift amount θs for each stream included in the received data.

[0038] FIG. 9 is a conceptual diagram for explaining the effect of the phase shift according to this embodiment. As shown in FIG. 9, the distribution (symbol distribution) of the symbol sequence in the constellation becomes closer to a circle due to the phase shift. Since the symbol phase at which the peak power occurs is shifted, the peak power decreases when signals are superimposed by precoding. Furthermore, since the zero point is not passed when transitioning to a symbol at a point-symmetric position, the average power increases compared to when the phase shift is not performed. In this way, the PAPR can be reduced by performing a phase shift when modulating the transmission data.

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

[0040] In step S110, the transmitting device 100 performs "phase shift amount determination processing". That is, the transmitting device 100 determines the phase shift amount θs for each stream of transmission data. More specifically, the transmitting device 100 selects one from a plurality of types of phase shift patterns PAT prepared in advance. For example, the transmitting device 100 selects one for which the PAPR of the transmission data after pre-coding processing is minimized from among the plurality of types of phase shift patterns PAT. As another example, the transmitting device 100 may select one for which the reception quality of the transmission data in the receiving device 200 is maximized from among the plurality of types of phase shift patterns PAT. Then, the transmitting device 100 determines the phase shift amount θs for each stream according to the selected phase shift pattern PAT.

[0041] In step S120, the transmitting device 100 performs "modulation processing" on the transmission data. More specifically, the transmitting device 100 modulates the transmission data by a predetermined modulation method and further shifts the phase according to the above phase shift amount θs for each stream.

[0042] In step S130, the transmitting device 100 performs "signal addition processing" 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 stream.

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

[0044] In step S150, the transmitting device 100 performs "transmission processing" for transmitting the transmission data after pre-coding processing from the transmitting device to the receiving device.

[0045] During communication, the transmitting device 100 may appropriately update the phase shift pattern PAT. When updating, the transmitting device 100 may review all types of phase shift patterns PAT again and select one from all types of phase shift patterns PAT. Alternatively, the transmitting device 100 may review 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 the present 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 configuration example 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 stream 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. The plurality of types of phase shift patterns PAT each define a different phase shift amount θs. The phase shift amount determination unit 150 provisionally selects the plurality of types of phase shift patterns PAT one by one in order. The phase shift amount determination unit 150 notifies the modulation unit 110A of the phase shift amount θs for each stream defined by the provisionally selected phase shift pattern PAT.

[0051] The modulation unit 110A receives information on the phase shift amount θs for each stream 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 according to the phase shift amount θs for each stream (see FIG. 7). The modulation unit 110A outputs the transmission data TD1 after the modulation process.

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

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

[0054] The phase shift amount determination unit 150 acquires information on the 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 stream 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 stream. Thereafter, the modulation unit 110A performs modulation processing using the phase shift amount θs notified from 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 one selected phase shift pattern PAT. Then, the signal adding unit 160 performs "signal addition processing" to add the index signal to the stream of 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 Fig. 12 is a block diagram showing a second configuration example of the transmission device 100. Descriptions that overlap with the first configuration example shown in Fig. 11 will be omitted as appropriate.

[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 a plurality of types of phase shift patterns PAT. Then, the phase shift amount determination unit 150 selects one of the plurality of 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 stream according to the selected one 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 stream. Thereafter, the modulation unit 110A performs modulation processing using the phase shift amount θs notified from 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 executes the control program to realize the functions of the processor.

[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 reception data (reception signal) RD0. The amplifier 210 amplifies the reception data RD0 and outputs reception data RD1. The A / D converter 220 A / D converts the reception data RD1 and outputs reception 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 a plurality of 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 added to the received data RD2. The phase shift pattern acquisition unit 240 recognizes the phase shift pattern PAT applied to the transmission data of the predetermined data unit based on the index signal. Then, the phase shift pattern acquisition unit 240 acquires a phase shift amount θs for each stream defined by the recognized phase shift pattern PAT. The demodulation unit 230 demodulates the received data RD2 by a predetermined demodulation method and returns the phase by the phase shift amount θs for each stream.

[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 in a computer-readable recording medium. The processor executes the control program to realize the functions of the processor. 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 section 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 stream of transmission data; a modulation process of modulating the transmission data and further shifting a phase for each of the streams 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 multiple phase shift patterns that minimizes a peak to average power ratio (PAPR) of the transmission data after the precoding process, or selects one of the multiple phase shift patterns that maximizes reception quality of the transmission data in the receiving device; determining the phase shift amount for each of the streams according to the selected phase shift pattern; Including, The wireless communication method further includes a signal addition process of adding an index signal indicative of the selected phase shift pattern to the stream of transmission data; the phase shift amount determination process and the signal addition process are performed in predetermined data units, which are frames or slots; The signal addition process adds the index signal to the beginning or end of the predetermined data unit. A wireless communication method.

2. 2. The wireless communication method according to claim 1, The amount of phase shift is different between two or more streams of the transmission data. A wireless communication method.

3. 3. The wireless communication method according to claim 2, The amount of phase shift differs by a constant amount between the two or more streams of the transmission data. A wireless communication method.

4. A wireless communication method according to any one of claims 1 to 3, 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 A 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 stream of transmission data; a modulation process of modulating the transmission data and further shifting a phase for each of the streams 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 multiple phase shift patterns that minimizes a peak to average power ratio (PAPR) of the transmission data after the precoding process, or selects one of the multiple phase shift patterns that maximizes reception quality of the transmission data in the receiving device; determining the phase shift amount for each of the streams 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 stream of the transmission data; the phase shift amount determination process and the signal addition process are performed in predetermined data units, which are 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 includes: 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 stream of transmission data; a modulation unit that modulates the transmission data and further shifts a phase for each of the streams according to the phase shift amount; A precoding unit that performs precoding on the modulated transmission data; a transmitting unit that transmits the transmission data after the precoding 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 preceding, or select one of the phase shift patterns 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 streams according to the selected phase shift pattern; the transmitting device further comprises a signal adding unit that adds an index signal indicating the selected phase shift pattern to the stream of the transmission data; The processing by the phase shift amount determining unit and the signal adding unit is performed in predetermined data units, which are frames or slots; The signal adding unit adds the index signal to the beginning or end of the predetermined data unit. Transmitting device.

Images