Reception device, transmission device, and wireless power transmission system

Abstract

A reception device (120) comprises: a reception unit (121) that receives a first transmission signal (10A) transmitted in a first frequency band from a first transmission device (110) included in a plurality of transmission devices (110), and a second transmission signal (10B) transmitted in a second frequency band at least partially different from the first frequency band from a second transmission device (110) included in the plurality of transmission devices (110); and an output unit (122) that outputs the power of a composite signal (11) of a plurality of transmission signals (10) including the first transmission signal and the second transmission signal.

Description

Receiving device, transmitting device, and wireless power transmission system

[0001] The present invention relates to a receiving device, a transmitting device, and a wireless power transmission system.

[0002] 2. Description of the Related Art One of the wireless power supply methods (which may also be referred to as "wireless power transmission" or "wireless power supply") that can supply power to a device in a contactless manner is a method called a radio wave reception method.

[0003] The radio wave reception method is a technique in which, for example, a transmission signal sent from a transmitting device that supplies power (transmits power) is received by a receiving device using an antenna such as a rectenna antenna, and the received signal is converted into direct current using a rectifier, thereby supplying power to the power supply target.

[0004] In the radio wave reception system, the transmission distance of a transmission signal from a transmitting device to a receiving device can be several meters or more.

[0005] JP 2024-046254 A JP 2023-135122 A

[0006] In a receiving device, the power conversion efficiency of a signal input to an antenna such as a rectenna antenna increases as the PAPR (Peak to Average Power Ratio) increases. On the other hand, when a power greater than a certain value is input to a power amplifier (PA) provided in a transmitting device, the output power from the PA becomes saturated. Therefore, the power conversion efficiency of a signal input to a PA may increase as the PA's PA ...

[0007] Thus, in a wireless power supply method such as a radio wave reception method, it may be difficult for a transmitter to transmit a transmission signal that can be converted by a receiver with high power conversion efficiency. In other words, it may be difficult for a receiver to convert a received signal from a transmitter with high power conversion efficiency.

[0008] In one aspect, an object of the present invention is to provide a receiving device, a transmitting device, and a wireless power transmission system that improve power conversion efficiency in wireless power transmission.

[0009] In one aspect, a receiving device is provided that includes: a receiving unit that receives a first transmission signal transmitted in a first frequency band from a first transmission device included in a plurality of transmission devices; and a second transmission signal transmitted in a second frequency band that is at least partially different from the first frequency band from a second transmission device included in the plurality of transmission devices; and an output unit that outputs the power of a combined signal of a plurality of transmission signals including the first transmission signal and the second transmission signal.

[0010] In one aspect, the present invention can improve power conversion efficiency in wireless power transmission.

[0011] 1 is a block diagram showing an example of a system configuration according to an embodiment; FIG. 2 is a diagram for explaining an example of a wireless power transmission technique according to an embodiment; FIG. 3 is a diagram for explaining an example of a configuration of a wireless communication system according to a first embodiment; FIG. 4 is a diagram for explaining an example of a functional configuration of a base station device; FIG. 5 is a diagram for explaining an example of a hardware configuration of a base station device; FIG. 6 is a diagram for explaining an example of a functional configuration of a terminal device; FIG. 7 is a diagram for explaining an example of a hardware configuration of a terminal device; FIG. 8 is a sequence diagram showing an example of an operation of wireless power transmission processing in a wireless communication system according to a first embodiment; FIG. 9 is a diagram for explaining an example of an operation of wireless power transmission processing in a wireless communication system according to a first embodiment; FIG. 10 is a flowchart showing an example of an operation of a selection processing by a terminal device according to a first embodiment; FIG. 11 is a diagram for explaining an example of an operation of a wireless communication system according to a second embodiment; FIG. 12 is a diagram for explaining an example of a configuration of a wireless communication system according to a third embodiment; FIG. 13 is a diagram for explaining an example of a wireless power transmission technique according to the third embodiment;

[0012] The present embodiment will be described in detail below with reference to the drawings. The problems and examples in this specification are merely examples and do not limit the scope of the rights of the present application. Furthermore, even if the expressions used are different, the technology of the present application can be applied as long as they are technically equivalent, and do not limit the scope of the rights. Furthermore, each embodiment can be combined as appropriate within the scope of not causing any contradiction in the processing content.

[0013] Furthermore, the terms used and technical content described in this specification may be those described in specifications and contributions as standards related to communications such as 3GPP (Third Generation Partnership Project) (registered trademark).

[0014] Hereinafter, embodiments of a receiving device, a transmitting device, and a wireless power transmission system disclosed in the present application will be described in detail with reference to the accompanying drawings. Note that the disclosed technology is not limited to the following embodiments.

[0015] [A] Description of a wireless power transmission method according to an embodiment Fig. 1 is a block diagram showing an example of the configuration of a system 100 according to an embodiment. As shown in Fig. 1, the system 100 may include a plurality of (X: X is an integer of 2 or more; in the example of Fig. 1, X=2) wireless transmission devices 110 and wireless reception devices 120.

[0016] The system 100 is an example of a wireless power transmission system, and is a system that performs wireless power transmission from a wireless transmitting device 110 to a wireless receiving device 120. The system 100 according to the embodiment may be, for example, a wireless communication system that performs wireless power transmission and wireless communication.

[0017] The wireless transmitting device 110 is an example of a transmitting device. When the system 100 is a wireless communication system, the wireless transmitting device 110 may be, for example, a base station device or a relay station device.

[0018] Each of the multiple wireless transmitting devices 110 transmits a wireless power supply signal 10 to the wireless receiving device 120 at a predetermined timing using at least a portion of different frequency bands. The wireless power supply signal 10 is an example of a transmission signal. In this manner, the system 100 according to the embodiment transmits the wireless power supply signal 10 from multiple transmission points, in other words, from multiple power supply sources.

[0019] In the following description, when distinguishing between the wireless transmission devices 110, they may be referred to as "wireless transmission device #0" and "wireless transmission device #1" (see FIG. 1 ). "#0" and "#1" are examples of identification information of the wireless transmission devices 110. The wireless transmission device #0 is an example of a first transmission device included in the multiple transmission devices, and the wireless transmission device #1 is an example of a second transmission device included in the multiple transmission devices. Furthermore, the wireless power supply signals 10 transmitted by the wireless transmission devices #0 and #1, respectively, may be referred to as wireless power supply signals 10A and 10B. The wireless power supply signal 10A is an example of a first transmission signal transmitted from the first transmission device in a first frequency band, and the wireless power supply signal 10B is an example of a second transmission signal transmitted from the second transmission device in a second frequency band at least partially different from the first frequency band.

[0020] The wireless receiving device 120 is an example of a receiving device. When the system 100 is a wireless communication system, the wireless receiving device 120 may be, for example, a terminal device or a relay station device.

[0021] The wireless receiving device 120 receives the wireless power supply signals 10A and 10B transmitted from the wireless transmitting devices #0 and #1, respectively, and outputs the power of a composite signal of multiple wireless power supply signals 10 including the wireless power supply signals 10A and 10B.

[0022] 2 is a diagram for explaining an example of a wireless power transmission technique according to the embodiment. Hereinafter, an example of a wireless power transmission technique according to the embodiment will be described with reference to FIG.

[0023] For example, the wireless transmission device 110 maps signal A to a frequency band that is different between wireless transmission devices #0 and #1 and that is available for wireless power transmission (see symbol A1). In the example of Fig. 2, wireless transmission device #0 maps signal A to a frequency band of frequencies f0 to f1 (hereinafter, sometimes referred to as "frequency band f0 to f1"), which is an example of a first frequency band. Wireless transmission device #1 maps signal A to a frequency band of frequencies f1 to f2 (hereinafter, sometimes referred to as "frequency band f1 to f2"), which is an example of a second frequency band.

[0024] Hereinafter, a frequency band that can be used for wireless power transmission may be referred to as a "power supply frequency band." Examples of the power supply frequency band include a frequency band that is associated with or assigned to wireless power transmission, an unused frequency band (e.g., a reserved frequency band), and other frequency bands that are not used for other purposes such as wireless communication. The frequency band is an example of a wireless resource. Examples of the frequency band include subcarriers that constitute an OFDM (Orthogonal Frequency Division Multiplexing) signal. The power supply frequency band may be associated with wireless power transmission, for example, in information that manages or specifies a schedule of wireless resources, and may be allocated to wireless power transmission in scheduling information, for example. The frequency band may be allocated to wireless power transmission in units of resource blocks (RBs), each consisting of 12 subcarriers.

[0025] The frequency bands f0-f1 and f1-f2 are examples of frequency bands for power supply in which at least a portion of the frequency band is different from one another. While FIG. 2 illustrates a case in which the frequency bands f0-f1 and f1-f2 are frequency bands obtained by dividing the frequency band for power supply and are different from one another, they may also be frequency bands in which some of the frequencies overlap. For example, when the frequency band for power supply is divided into frequency bands f0-f3, wireless transmission device #0 may map signal A to frequency bands f0-f2, and wireless transmission device #1 may map signal A to frequency bands f1-f3 (not shown). The frequency bands to which wireless transmission devices #0 and #1 each map signal A may be non-adjacent frequency bands, for example, frequency bands f0-f1 and f2-f3 (not shown). The relationship between frequencies f1, f2, and f3 is, for example, f1<f2<f3.

[0026] Signal A may be a signal for wireless power transmission, and may be, for example, a signal including various data (for example, a data sequence). For example, signal A may be a dummy signal including dummy data, a signal known in system 100, or a signal including data known in system 100.

[0027] Here, the power conversion efficiency of a signal input to an antenna (antenna 121 described later) in wireless receiving device 120 is higher when the PAPR is larger. On the other hand, the power conversion efficiency of signal A input to PA 111 of wireless transmitting device 110 is higher when the PAPR is smaller. In other words, the power conversion efficiency can decrease as the PAPR of signal A increases.

[0028] In an embodiment, the PAPR of signal A may be approximately the same as the PAPR of a signal used for wireless communication. "Approximately the same" may mean, for example, that the PAPR of signal A does not need to be so large as to cause a decrease in power conversion efficiency in PA 111 (e.g., a decrease below an allowable lower limit). Therefore, the PAPR of signal A may be smaller or larger than the PAPR of a signal used for wireless communication.

[0029] 2, the PAPRs of the wireless power supply signals 10A and 10B transmitted by the wireless transmission devices #0 and #1 are both 10 dB (decibels). Note that the PAPRs of the wireless power supply signals 10 transmitted from the multiple wireless transmission devices 110 may be different from each other.

[0030] The radio transmitting device 110 modulates the signal A that has been mapped to the frequency band f0 to f1 or f1 to f2. As the modulation method, a method according to various modulation formats may be used.

[0031] In the example shown in FIG. 2, the wireless transmission device 110 maps signal A to one OFDM symbol. In this case, the wireless transmission device 110 may modulate signal A by performing a time-domain inverse fast Fourier transform (IFFT) on signal A that has been mapped to the frequency bands f0 to f1 or f1 to f2 (see symbol A2). The wireless transmission device 110 may insert a cyclic prefix (CP) into the signal after the IFFT. The wireless transmission device 110 may also perform frequency conversion (upconversion) of the modulated signal to a radio frequency (RF) frequency.

[0032] The radio transmitting device 110 performs power amplification on the modulated signal, for example, a signal that has been frequency-converted to a radio frequency, using the PA 111. The PA 111 may be any of various power amplifiers.

[0033] The wireless transmitting device 110 may control the strength of the power amplification of the signal A by the PA 111 so that a predetermined power conversion efficiency is obtained in the power amplification of the signal used for wireless power transmission by the PA 111. The "predetermined power conversion efficiency" may be, for example, the same as the power conversion efficiency in the power amplification of the signal used for wireless communication. Note that, when the PAPR of the signal A is smaller than the PAPR of the signal used for wireless communication, the "predetermined power conversion efficiency" may be higher than the power conversion efficiency in the power amplification of the signal used for wireless communication.

[0034] The wireless transmission device #0 transmits the signal after power amplification by the PA 111 as a wireless power supply signal 10A, which is an example of a first transmission signal, from the antenna 112. The wireless transmission device #1 transmits the signal after power amplification by the PA 111 as a wireless power supply signal 10B, which is an example of a second transmission signal, from the antenna 112. Each of the wireless power supply signals 10A and 10B may be transmitted at a predetermined timing, for example.

[0035] In other words, wireless transmission device #0 generates wireless power supply signal 10A using a frequency band that is at least partially different from the frequency band used for wireless power supply signal 10B that wireless transmission device #1 transmits to wireless reception device 120 at a predetermined timing. Then, wireless power supply signal #0 transmits wireless power supply signal 10A to wireless reception device 120 at a predetermined timing. Similarly, wireless transmission device #1 generates wireless power supply signal 10B using a frequency band that is at least partially different from the frequency band used for wireless power supply signal 10A that wireless transmission device #0 transmits to wireless reception device 120 at a predetermined timing. Then, wireless power supply signal #1 transmits wireless power supply signal 10B to wireless reception device 120 at a predetermined timing.

[0036] The wireless receiving device 120 receives a plurality of wireless power feeding signals 10 including wireless power feeding signals 10A and 10B transmitted at predetermined timings from the wireless transmitting devices #0 and #1, respectively, by an antenna 121. The antenna 121 may be, for example, an antenna compatible with wireless power transmission, such as a rectenna antenna.

[0037] Receiving a plurality of wireless power supply signals 10 transmitted at a predetermined timing may be understood as, for example, receiving a plurality of wireless power supply signals 10 simultaneously, in other words, combining a plurality of wireless power supply signals 10. "Simultaneously" may mean that at least a portion of the plurality of wireless power supply signals 10 overlaps with one another in the time domain.

[0038] The wireless receiving device 120 simultaneously receives a plurality of wireless power supply signals 10 to obtain a composite signal 11 obtained by combining the plurality of wireless power supply signals 10. The composite signal 11 is an example of a received signal. For example, the wireless receiving device 120 can obtain the composite signal 11 obtained by combining the wireless power supply signals 10A and 10B by receiving a signal whose baseband is in the frequency range of f0 to f2.

[0039] Since the multiple wireless power supply signals 10 are transmitted at a predetermined timing, in other words, in the same time domain, using at least some of the frequency bands that are different from each other, the wireless receiving device 120 receives multiple wireless power supply signals 10 that are phase-shifted from each other.

[0040] When multiple wireless power supply signals 10 with mutually shifted phases are combined, even if the average amplitudes (signal strength, power) of the wireless power supply signals 10 are similar, the amplitudes will reinforce each other over a certain period of time. As a result, the combined signal 11 has a higher ratio of peak amplitude value to average amplitude value, in other words, a higher PAPR, than the wireless power supply signal 10. In the example of Fig. 2, wireless power supply signals 10A and 10B with a PAPR of 10 dB are combined to obtain a combined signal 11 with a PAPR of 13 dB.

[0041] In order to increase the PAPR of the combined signal 11 more than the PAPR of each of the signals for wireless power supply 10, the signals A generated by the wireless transmitting devices #0 and #1 may contain, for example, the same or substantially the same data (e.g., data series). Note that the signals A generated by the wireless transmitting devices 110 do not necessarily need to contain the same or substantially the same data, but may contain various data such that the PAPR of the combined signal 11 becomes greater than the PAPR of the signal for wireless power supply 10 when combined by the wireless receiving device 120.

[0042] The wireless receiving device 120 outputs the power of the composite signal 11 via the power output unit 122. For example, if the antenna 121 is a rectenna antenna, the power output unit 122 may include a rectifier that converts the signal into a direct current, and may output the power of the composite signal 11 as a power supply signal by converting the composite signal 11 into a direct current using the rectifier. The power supply signal output from the power output unit 122 may be supplied to a power supply target device such as a storage battery.

[0043] The power supply target device may be provided in, for example, the wireless receiving device 120, or may be connected to the wireless receiving device 120 in a wired or wireless manner, or both. When the wireless receiving device 120 and the power supply target device are connected wirelessly, various wireless power transmission methods, including the method according to the embodiment, may be used to output power from the wireless receiving device 120 to the power supply target device.

[0044] The power supply target device may include, for example, one or both of a storage battery and a load device. The storage battery may be a device that can be charged with supplied power, such as a secondary battery such as various types of batteries, or an electronic element such as a capacitor. The load device may be a device that operates using power. For example, the load device may be a device (e.g., a sensor device) installed in an AV device, home appliance, office equipment, vending machine, computer, medical equipment, or other household or industrial equipment, or may be part of such a device. The wireless receiving device 120 may be considered as a device having a power supply function to the load device, or as a device having both a power supply function and a wireless communication function. Alternatively, the wireless receiving device 120 itself may be considered as a load device having both a power supply function and a wireless communication function.

[0045] As described above, in the system 100 according to the embodiment, the first wireless transmission device #0 included in the plurality of wireless transmission devices 110 transmits the wireless power supply signal 10A in a first frequency band. The second wireless transmission device #1 included in the plurality of wireless transmission devices 110 transmits the wireless power supply signal 10B in a second frequency band that is at least partially different from the first frequency band. In other words, each of the plurality of wireless transmission devices 110 transmits the wireless power supply signal 10 at a predetermined timing using frequency bands that are at least partially different from each other. Furthermore, the wireless reception device 120 receives, for example, simultaneously receives the plurality of wireless power supply signals 10 including the wireless power supply signal 10A and the wireless power supply signal 10B, and outputs the power of a combined signal 11 of the plurality of wireless power supply signals 10.

[0046] The wireless receiving device 120 can generate (acquire) the composite signal 11 having a higher PAPR than the individual wireless power supply signals 10. In other words, each wireless transmitting device 110 may generate and transmit the wireless power supply signal 10 having a lower PAPR than the composite signal 11 acquired by the wireless receiving device 120.

[0047] Therefore, it is possible to improve the power conversion efficiency in the wireless receiving device 120 while suppressing or mitigating a decrease in the power conversion efficiency (e.g., power amplification efficiency) in the PA 111 of the wireless transmitting device 110, and to achieve efficient wireless power transmission in the system 100. In other words, it is possible to improve the power conversion efficiency in wireless power transmission.

[0048] Next, various embodiments of a method for improving the power conversion efficiency in wireless power transmission will be described in order.

[0049] [B] First Example <Configuration Example of Wireless Communication System 1> Fig. 3 is a diagram showing an example of the configuration of a wireless communication system 1 according to a first example. The wireless communication system 1 is an example of a system 100, and may perform wireless power transmission and wireless communication.

[0050] The wireless communication system 1 may include base station devices 200A and 200B and a terminal device 300. The base station device 200A forms a cell C10. The base station device 200B forms a cell C11. The terminal device 300 is present in both cell C10 and cell C11. In other words, the terminal device 300 is present within the coverage of each of the base station devices 200A and 200B. In the following description, when there is no need to distinguish between the base station devices 200A and 200B, they may be referred to as the base station device 200.

[0051] The base station device 200 may be, for example, a small radio base station device (including a micro radio base station device, a femto radio base station device, etc.) such as a macro radio base station device or a pico radio base station device, or may be a radio base station device of various scales. The base station device 200 may also be a mobile device having base station functionality, such as an artificial satellite, a stratospheric platform such as a High Altitude Platform Station (HAPS), a vehicle, or an airplane. The base station device 200 is an example of the radio transmitting device 110 or a transmitting device, and may be referred to as a base station, a radio communication device, a communication device, etc.

[0052] The base station devices 200A and 200B are connected to each other via a network N10 so that they can communicate with each other. The network N10 may be a wired connection, a wireless connection, or a combination of a wired connection and a wireless connection. The network N10 may include a core network.

[0053] Furthermore, the base station device 200 is connected to a network via a wired connection with a higher-level device or other base station device (not shown). Note that the base station device 200 may be connected to a network device via a wireless connection instead of or in addition to a wired connection. In the following description, for a certain base station device 200, other base station devices 200A or 200B different from the base station device 200 itself, or higher-level devices or other base station devices (not shown), may be collectively referred to as "network devices."

[0054] The base station device 200 may be configured with a wireless communication function with the terminal device 300 and a digital signal processing and control function separated into separate devices. In this case, the device with the wireless communication function may be called an RRH (Remote Radio Head), and the device with the digital signal processing and control function may be called a BBU (Base Band Unit). The RRH may be installed extending from the BBU. The RRH and the BBU may be connected by wire using optical fiber or the like, or wirelessly. Instead of separating the base station device 200 into an RRH and a BBU, the base station device 200 may be separated into, for example, a CU (Central Unit), a DU (Distributed Unit), and an RU (Radio Unit). The DU may include, for example, a MAC (Media Access Control) layer function. The DU may also include, for example, an RLC (Radio Link Control) layer function. The RU includes at least an RF (Radio Frequency) radio circuit. The DU and RU may be integrated into one unit.

[0055] The terminal device 300 may be, for example, a device (e.g., a sensor device) installed in an AV device, a home appliance, an office device, a vending machine, a computer, a medical device, or other household appliance or industrial device, or a wireless terminal device such as a part of such a device. The terminal device 300 may also be, for example, a mobile phone, a smartphone, a PDA (Personal Digital Assistant), a personal computer, a vehicle, an airplane, a drone, or any other device having a wireless communication function, or a part of such a device. The terminal device 300 is an example of the wireless receiving device 120 or a receiving device, and may be referred to as a terminal, a wireless communication device, a communication device, a mobile station, or the like. The terminal device 300 may include the power supply target device described above, or may be connected to the power supply target device in one or both of a wired and wireless manner.

[0056] <Configuration Example of Base Station Device 200> Fig. 4 is a diagram showing an example of the functional configuration of the base station device 200. The base station device 200 may include, for example, a wireless communication unit 210, a control unit 220, a storage unit 230, and a communication unit 240. These functional configuration units are connected to each other so as to enable input and output of signals or data in one direction or two directions.

[0057] The wireless communication unit 210 includes a transmitting unit 211 and a receiving unit 212, and communicates with the terminal device 300, for example, by wireless communication.

[0058] The transmitting unit 211 may transmit a downlink signal to the terminal device 300. The downlink signal may be, for example, a measurement signal (for example, a synchronization signal block (SSB) or a reference signal) that is measured by the terminal device 300, a signal for a random access procedure, a signal for a radio resource control (RRC) layer, a downlink data signal, a downlink control signal, or the like.

[0059] The transmitter 211 may also transmit the wireless power supply signal 10 or a training signal, which will be described later.

[0060] The receiving unit 212 may receive an uplink signal transmitted from the terminal device 300. The uplink signal may be, for example, a random access procedure signal, an RRC layer signal, an uplink data signal, an uplink control signal, or the like.

[0061] The control unit 220 controls the base station device 200. As an example, the control unit 220 can control the establishment of an RRC connection with the terminal device 300, signal processing of a signal received by the receiving unit 212, creation of a transport block (TB), mapping of the transmission block to radio resources, and the like.

[0062] The control unit 220 may also perform control related to wireless power transmission. The control related to wireless power transmission may include, for example, control of creating a transmission block (TB) including the wireless power supply signal 10 or a training signal, mapping the transmission block to radio resources, and processing according to control information included in a control signal received by the receiving unit 212. The control related to wireless power transmission may also include control related to the wireless power supply signal 10 or the training signal between the network device, for example, determination or selection of a data sequence, control of transmission timing, etc.

[0063] The storage unit 230 can store, for example, downstream data signals.

[0064] The storage unit 230 can store, for example, the wireless power supply signal 10 or the training signal. Furthermore, the storage unit 230 can store control information from the terminal device 300, control information between the terminal device 300 and the network device, and the like.

[0065] The communication unit 240 connects to a network device via a wired or wireless connection and communicates with the network device. The communication between the communication unit 240 and the network device may include transmission and reception of a control signal used for control of the wireless power supply signal 10 or the training signal. A data signal received by the communication unit 240 and intended for the terminal device 300 may be stored in the storage unit 230. The wireless communication unit 210 and the communication unit 240 may be collectively referred to as a communication unit.

[0066] 5 is a diagram illustrating an example of the hardware configuration of the base station device 200. The base station device 200 may include, for example, an antenna 410, an RF circuit 420, a CPU (Central Processing Unit) 430, a DSP (Digital Signal Processor) 440, a memory 450, and a network IF (Interface) 460. The antenna 410 may be included in the RF circuit 420. The CPU 430 is connected to each hardware component via a bus to enable input and output of various signals and data signals. The memory 450 may include at least one of a RAM (Random Access Memory) such as an SDRAM (Synchronous Dynamic Random Access Memory), a ROM (Read Only Memory), and a flash memory, and may store programs, control information, data signals, and the like.

[0067] The transmitter 211 and receiver 212 (or wireless communication unit 210) shown in FIG. 4 may be realized by, for example, an RF circuit 420, or an antenna 410 and an RF circuit 420. The RF circuit 420 may include, for example, a power amplifier (e.g., PA111 shown in FIG. 2). The controller 220 shown in FIG. 4 may be realized by, for example, a CPU 430, a DSP 440, a memory 450, a digital electronic circuit (not shown), etc. Examples of the digital electronic circuit include an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), and a large scale integration (LSI). The storage unit 230 shown in FIG. 4 may be realized by, for example, the memory 450. The communication unit 240 shown in FIG. 4 may be realized by, for example, a network IF 460.

[0068] 6 is a diagram showing an example of the functional configuration of the terminal device 300. The terminal device 300 may include, for example, a communication unit 310, a control unit 320, and a storage unit 330. These functional configuration units are connected to each other so as to enable input and output of signals or data in one direction or two directions.

[0069] The communication unit 310 includes a transmission unit 311 and a reception unit 312, and performs communication, for example, wireless communication, with each of the base station devices 200A and 200B.

[0070] The transmitter 311 transmits signals, such as data signals, control signals, etc., via wireless communication via an antenna. The transmitter 311 transmits uplink signals, such as random access procedure signals, RRC layer signals, uplink data signals, and uplink control signals.

[0071] The transmitter 311 may also transmit a control signal including control information related to the wireless power supply signal 10 or the training signal.

[0072] The receiver 312 receives signals transmitted from the base station device 200, such as downlink signals such as random access procedure signals, downlink data signals, and downlink control signals. The signals received by the receiver 312 may include, for example, reference signals used for channel estimation, demodulation, etc. The antenna may be shared by the transmitter 311 and the receiver 312.

[0073] The receiver 312 may also receive the wireless power supply signal 10 or the training signal from each of the base station devices 200A and 200B, calculate the PAPR of the received signal (for example, the combined signal 11), and perform other operations.

[0074] The control unit 320 controls the terminal device 300. As an example, the control unit 320 can control the establishment of an RRC connection with the base station device 200, signal processing of a signal received by the receiving unit 312, creation of a transmission block (TB), mapping of the transmission block to radio resources, and the like.

[0075] The control unit 320 may also perform control related to wireless power transmission. The control related to wireless power transmission may include, for example, control information related to the wireless power supply signal 10 or the training signal, creation of a transmission block (TB) including feedback information, mapping of the transmission block to a wireless resource, etc. The control related to wireless power transmission may also include control of signal processing of the combined signal 11 (received signal) received by the receiving unit 312, processing using the PAPR calculated for the combined signal 11, etc.

[0076] The storage unit 330 can store, for example, uplink data signals. The storage unit 330 can also store configuration information (or setting information) related to wireless communication transmitted from the base station device 200.

[0077] The storage unit 330 can also store, for example, the composite signal 11. Furthermore, the storage unit 330 can store the results of processing performed by the control unit 320 using the composite signal 11, and the like.

[0078] FIG. 7 is a diagram illustrating an example of the hardware configuration of the terminal device 300. The terminal device 300 may include, for example, an antenna 510, an RF circuit 520, a CPU 530, a DSP 540, a memory 550, and a charging circuit 560. The antenna 510 may be included in the RF circuit 520. The antenna 510 may include, for example, an antenna for receiving the wireless power supply signal 10 in wireless power transmission, such as a rectenna antenna. The memory 540 may include at least one of a RAM such as an SDRAM, a ROM, and a flash memory, and may store programs, control information, data signals, and the like. The charging circuit 560 may supply (e.g., feed power to) a power supply target device, such as a rechargeable battery or a load device, with the power of the composite signal 11 received by the RF circuit 520. The power supply target device may be included in the charging circuit 560.

[0079] The transmitter 311 and receiver 312 (or communication unit 310) shown in FIG. 6 , or the antenna 121 and power output unit 122 shown in FIG. 2 may be realized by, for example, an RF circuit 520, or the antenna 510, RF circuit 520, and a charging circuit 560. The control unit 320 shown in FIG. 6 is realized by, for example, a CPU 530, a DSP 540, a memory 550, a charging circuit 560, and a digital electronic circuit (not shown). Examples of the digital electronic circuit include an ASIC, an FPGA, and an LSI. The storage unit 330 shown in FIG. 6 may be realized by, for example, the memory 550.

[0080] <Operation Example of First Embodiment> Next, an operation example of the first embodiment will be described. In the first embodiment, a case where wireless power transmission is performed from two base station devices 200A and 200B to a terminal device 300 will be described as an example. As described above, the base station devices 200A and 200B are examples of wireless transmission devices 110, and are capable of performing the processes described with reference to FIGS. 1 and 2, for example, transmitting a wireless power supply signal 10. Furthermore, the terminal device 300 is an example of a wireless reception device 120, and is capable of performing the processes described with reference to FIGS. 1 and 2, for example, receiving a composite signal 11 of a plurality of wireless power supply signals 10.

[0081] Figure 8 is a sequence diagram showing an example of operation of wireless power transmission processing in the wireless communication system 1 according to the first embodiment, and Figure 9 is a diagram for explaining an example of operation of wireless power transmission processing in the wireless communication system 1 according to the first embodiment.

[0082] In the following description, it is assumed that, of the base station devices 200A and 200B, the base station device 200A functions as a main device (first transmission device) in wireless power transmission, and the base station device 200B functions as a secondary device (second transmission device) in wireless power transmission. In the following description, the base station device 200A may be referred to as base station device #0, and the base station device 200B may be referred to as base station device #1.

[0083] As illustrated in Fig. 8, base station device #0, which serves as the main device, transmits a training signal 12A from its wireless communication unit 210 (e.g., transmitter 211) to the terminal device 300 (see symbol P1A). Base station device #1, which serves as the secondary device, transmits a training signal 12B from its wireless communication unit 210 (e.g., transmitter 211) to the terminal device 300 (see symbol P1B). Training signals 12A and 12B (hereinafter, when no distinction is made between them, they will be referred to as training signal 12) may be transmitted at the same timing t1. The main device may be referred to as a device that forms a primary cell or a primary cell, and the secondary device may be referred to as a device that forms a secondary cell or a secondary cell.

[0084] The training signal 12 is an example of a first signal including multiple candidates for the wireless power supply signal 10. The training signal 12 may be, for example, a signal in which the pattern of one or both of the frequency band and the data is changed in the time domain. In other words, multiple patterns that are different from each other are an example of multiple candidates. The timing of the change in the time domain may be referred to as an interval. The timing of the change or each interval may be recognizable by the base station device 200 and the terminal device 300. In the following description, a "sequence number" is used as an example of information for identifying each interval in the training signal 12.

[0085] The training signal 12A transmitted by base station device #0 and the training signal 12B transmitted by base station device #1 may be determined so that the combinations of frequency bands to which data are mapped are different in the time domain (in other words, for each section). Details of the training signal 12 will be described later.

[0086] 9 shows an example in which base station device #0 transmits a training signal 12A mapped to radio resources of frequency bands f0 to f1 as a transmission signal in a certain time domain, while reference symbol B2 in FIG. 9 shows an example in which base station device #1 transmits a training signal 12B mapped to radio resources of frequency bands f1 to f2 as a transmission signal in a certain time domain.

[0087] Hereinafter, the training signal 12 and the wireless power supply signal 10 may be referred to as "transmission signal." The transmission signal may be mapped to, for example, one or more (as an example, a plurality of) subcarriers. In the example shown in FIG. 9 , a signal mapped to a plurality of subcarriers, in other words, a signal composed of a plurality of subcarriers, is referred to as "power supply SCs." Note that the transmission signal transmitted from the base station device 200A may be referred to as a first transmission signal. Also, the transmission signal transmitted from the base station device 200B may be referred to as a second transmission signal.

[0088] The terminal device 300 receives, via the communication unit 310 (for example, the receiving unit 312), the training signals 12A and 12B whose transmission starts at the same timing t1. The signal received by the receiving unit 312 is a combined signal 11 obtained by combining the training signals 12A and 12B. The terminal device 300 selects, via the control unit 320, a signal (a generated signal) to be generated by the base station device 200 for wireless power feeding, in accordance with the combined signal 11.

[0089] 9 shows an example in which the terminal device 300 receives a combined signal 11 of the training signals 12A and 12B by receiving a transmission signal in frequency bands f0 to f2 in a certain time domain, for example. The receiving unit 312 of the terminal device 300 calculates, for example, the PAPR of the entire combined signal 11 in the training signal 12 (hereinafter, may be referred to as "PAPR_rx"). Then, the control unit 320 of the terminal device 300 may select an optimal generated signal as the wireless power supply signal 10 from the section of the training signal 12 by identifying the section of the sequence number in which the calculated PAPR_rx is optimal (for example, maximum). The method of selecting the optimal generated signal will be described in detail later.

[0090] The terminal device 300 feeds back control information related to the selected optimal generated signal, in other words, information related to candidate transmission signals, to the base station device #0 serving as the master device (see process P2 in FIG. 8 ). For example, the terminal device 300 may transmit a control signal B4 (see FIG. 9 ) including control information from the communication unit 310 (e.g., the transmission unit 311) to the base station device #0. The control information may include, for example, information for increasing or decreasing PAPR_rx, and may also include information related to the selected optimal generated signal, such as a sequence number. Note that the control signal B4 is, for example, a signal of the RRC (Radio Resource Control) layer, a signal of the MAC (Medium Access Control) layer, or a signal of the physical layer.

[0091] The control unit 220 of base station device #0 determines information about the generated signal using the control signal B4, and notifies base station device #1 of a signal B5 including the information via the communication unit 240 (see process P3 in FIG. 8 and reference symbol B5 in FIG. 9). Note that base station device #0 may determine the information about the generated signal based on the content of communication between base station device #0 and base station device #1. The information about the generated signal may include, for example, information about the data of the transmission signal, information about the timing of transmitting the transmission signal, etc.

[0092] Base station device #0 transmits a control signal B6 including control information from the transmitter 211 to the terminal device 300 (see process P4 in FIG. 8 ). The control signal B6 may include, for example, information regarding frequency bands (e.g., subcarriers) to which generated signals are mapped in the multiple base station devices 200, such as control information regarding frequency bands f0-f1 and f1-f2. The control signal B6 may also include, for example, control information regarding the timing of transmitting the transmission signal, in other words, the time domain. The control signal B6 may be, for example, an RRC layer signal, a MAC layer signal, or a physical layer signal.

[0093] Base station device #0 transmits, from the transmitter 211 to the terminal device 300, a wireless power supply signal 10A configured in a frequency band according to the information related to the generated signal at a predetermined timing according to the information related to the generated signal (see symbol P5A in FIG. 8 ). Furthermore, base station device #1 transmits, from the transmitter 211 to the terminal device 300, a wireless power supply signal 10B configured in a frequency band according to the information related to the generated signal at a predetermined timing according to the information related to the generated signal (see symbol P5B in FIG. 8 ). The wireless power supply signals 10A and 10B may be transmitted at the same timing t2.

[0094] The terminal device 300 receives the combined signal 11 of the wireless power supply signals 10A and 10B by receiving, via the receiving unit 312, a signal in a frequency band in accordance with the control information included in the control signal B6 in a time domain in accordance with the control information included in the control signal B6.

[0095] The terminal device 300 outputs the power of the composite signal 11 to the power supply target device by using the receiver 312 and the controller 320 (for example, the power output unit 122 shown in FIG. 2).

[0096] <Operation Example of Training Process> Next, an operation example of the training process in the wireless communication system 1 according to the first embodiment will be described. The training process may include a transmission process of the training signal 12 and a selection process of the wireless power supply signal 10. The transmission process of the training signal 12 is an example of the process P1 (P1A and P1B) shown in Fig. 8 , and the selection process of the wireless power supply signal 10 is an example of the process P2 shown in Fig. 8 .

[0097] FIG. 10 is a diagram for explaining an operation example of the training process in the wireless communication system 1 according to the first embodiment, and FIG. 11 is a flowchart showing an operation example of the selection process by the terminal device 300 according to the first embodiment.

[0098] (Example of Operation of Transmission Processing of Training Signal 12) First, a description will be given of an example of operation of transmission processing of the training signal 12 by the base station device 200. As shown by symbols C1 and C2 in Fig. 10, base station devices #0 and #1 transmit training signals 12A and 12B, respectively.

[0099] 10 , the training signal 12 includes N (N is an integer equal to or greater than 2) generated signal patterns (in other words, candidates for the wireless power supply signal 10) indicated by #0 to #N-1. Each of #0 to #N-1 is a sequence number and is an example of information for identifying a generated signal pattern. In the following description, each of the N generated signal patterns will be referred to as a "generated signal candidate," and when referring to a specific generated signal candidate, it may be referred to as generated signal candidate #0 to #N-1 using the sequence number.

[0100] The generated signal candidates #0 to #N-1 included in each of the training signals 12A and 12B may be prepared in advance, for example. As an example, the training signal 12 may be set in the base station device 200 from a network device (e.g., a higher-level device) via the communication unit 240.

[0101] Between the training signals 12A and 12B, generated signal candidates with the same sequence number, for example, between generated signal candidates #0, between generated signal candidates #1, ..., between generated signal candidates #N-1, may be transmitted at the same timing (in other words, the same section) in the time domain. Note that the beginning of the training signal 12 may be transmitted at a first timing.

[0102] Candidate signals having the same sequence number may be signals generated using at least some different frequency bands. Furthermore, candidate signals having the same sequence number may have different frequency bands, data patterns, or both, from candidate signals having other sequence numbers transmitted at different times in the time domain.

[0103] As a first example of generation signal candidates, the following shows an example of each generation signal candidate when the combination of frequency bands differs between generation signal candidates with different sequence numbers. In the first example, {frequency band of training signal 12A, frequency band of training signal 12B} is shown for each of generation signal candidates #0 to #5 (N=6). Note that in the following example, it is assumed that the data of each generation signal candidate is the same (does not change) between sequence numbers. Generation signal candidate #0: {f0 to f1, f1 to f2} Generation signal candidate #1: {f0 to f1, f2 to f3} Generation signal candidate #2: {f1 to f2, f0 to f1} Generation signal candidate #3: {f1 to f2, f2 to f3} Generation signal candidate #4: {f2 to f3, f0 to f1} Generation signal candidate #5: {f2 to f3, f1 to f2}

[0104] As a second example of generated signal candidates, the following shows an example of each generated signal candidate when the data combinations are different between generated signal candidates with different sequence numbers. In the example below, {data of training signal 12A, data of training signal 12B} is shown for each of generated signal candidates #0 to #2 (N=3). Note that in the example below, it is assumed that the frequency bands of each generated signal candidate are the same combination (do not change) between sequence numbers. For example, it is assumed that the frequency band of training signal 12A is f0 to f1 for all sequence numbers, and the frequency band of training signal 12B is f1 to f2 for all sequence numbers. Generated signal candidate #0: {A, A} Generated signal candidate #1: {B, B} Generated signal candidate #2: {C, C}

[0105] In the second example, A, B, and C each represent data (data series), and the same symbols may represent the same or substantially the same data. Data A, B, and C may also be referred to as signals A, B, and C, respectively.

[0106] As a third example of generated signal candidates, the patterns of the first and second examples described above may be combined. In this case, the training signal 12 may be generated that includes N=18 patterns of generated signal candidates.

[0107] The base station device 200 may transmit the training signal 12 including the above-described N generated signal candidates to the terminal device 300, for example, in the order of sequence numbers.

[0108] (Example of Operation of Selection Process of Wireless Power Supply Signal 10) Next, an example of operation of selection process of wireless power supply signal 10 by the terminal device 300 will be described. The following description will be made along the flowchart in Fig. 11 with reference to reference characters C3 to C6 in Fig. 10 .

[0109] 11, the terminal device 300 combines and receives the training signals 12A and 12B (step S1). For example, the terminal device 300 simultaneously receives the training signals 12A and 12B in the order of transmission or reception in the time domain, in other words, in the order of sequence numbers, thereby combining generated signal candidates #0 to #N-1 having the same sequence numbers (see symbol C3 in FIG. 10).

[0110] The terminal device 300 calculates the PAPR_rx for each interval (each sequence number) (step S2) and stores the calculated PAPR_rx in the storage unit 330 in a manner that allows the sequence numbers, for example, the order of calculation, to be distinguished (step S3). For example, the terminal device 300 calculates the PAPR_rx for each of the generated signal candidates #0, #1, ..., #N-1 as follows: ０ , PAPR １ , ..., PAPR Ｎ－１ (see reference symbol C4 in FIG. 10).

[0111] The terminal device 300 determines whether or not reception of the training signal 12 has ended (step S4). Whether or not reception of the training signal 12 has ended may be determined using, for example, a schedule (one example is scheduling information), the training signal 12, a control signal received from the base station device 200, or another signal.

[0112] If it is determined that reception of the training signal 12 has not been completed (NO in step S4), the process returns to step S1, and the terminal device 300 receives the subsequent generated signal candidates.

[0113] If it is determined that reception of the training signal 12 has ended (YES in step S4), the terminal device 300 selects a PAPR_rx that satisfies a predetermined condition, for example, the maximum PAPR_rx, from the multiple PAPR_rx values ​​stored in the storage unit 330. Then, the terminal device 300 acquires the sequence number of the selected PAPR_rx (step S5: see reference character C5 in FIG. 10 ). In other words, the terminal device 300 selects a candidate from each of the multiple training signals 12.

[0114] The terminal device 300 transmits a control signal B4 including the acquired sequence number to the base station device 200 (for example, the main device) (step S6: see reference symbol C6 in FIG. 10), and the selection process ends.

[0115] As described above, according to the wireless communication system 1 of the first embodiment, the training process can select the wireless power supply signal 10 that maximizes the PAPR_rx in the terminal device 300. For example, the terminal device 300 can identify a generated signal that maximizes the PAPR_rx in the frequency band (first example), data (second example), or a combination of these (third example) from the training signals 12 transmitted by each of the multiple base station devices 200. This allows the wireless communication system 1 to improve the power conversion efficiency of each of the base station devices 200 and the terminal device 300 in wireless power transmission.

[0116] [C] Second Example Next, a second example will be described. In the first example, a case was described in which the distance between each of the base station devices 200A and 200B and the terminal device 300 is constant. However, at least one of various conditions such as the relative distance, positional relationship, and communication quality between the terminal device 300 and each of the base station devices 200A and 200B may change over time.

[0117] In the second embodiment, a method for adjusting the transmission power of each of the base station devices 200A and 200B in accordance with such conditions, in other words, changes in the environment, will be described. Note that the wireless communication system 1 according to the second embodiment may have the same configuration as the wireless communication system 1 according to the first embodiment.

[0118] 12 is a diagram illustrating an example of the operation of the wireless communication system 1 according to the second embodiment. The base station device 200 according to the second embodiment may have a power adjustment function according to changes in the conditions between the base station device 200 and the terminal device 300. For example, each of the base station devices #0 and #1 adjusts the power according to the attenuation index a ０ and a １ may be calculated.

[0119] Attenuation index a ０ and a １ is an index indicating the degree to which signals transmitted between the base station devices #0 and #1 and the terminal device 300 are attenuated, and is an example of an index related to the transmission environment of wireless power transmission. ０ and a １ The information used to calculate the distance d between the base station devices #0 and #1 and the terminal device 300 is, for example, ０ and d １ , quality q of communication between the base station devices #0 and #1 and the terminal device 300 ０ and q １ , the moving speed of the terminal device 300 (not shown), and the like.

[0120] For example, each of the base station devices #0 and #1 is located at a distance d ０ and d １ , quality q ０ and q １ , information such as the moving speed of the terminal device 300 is measured and collected, and the attenuation index a is calculated using the collected information. ０ and a １ may be calculated.

[0121] Distance d ０ and d １ , quality q ０ and q １ The method of measuring information such as the moving speed of the terminal device 300 can be realized by various known methods, such as obtaining location information of the terminal device 300 (and the base station device 200), measuring various communication qualities, measuring the speed or acceleration of the terminal device 300, etc. Furthermore, the base station device 200 may cause the terminal device 300 to measure at least one of these types of information and receive the measurement results from the terminal device 300.０ and q １ (Communication quality) may include at least one type of information such as Received Signal Strength Indicator (RSSI), Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), and Signal-to-Interference-plus-Noise Ratio (SINR).

[0122] The base station device 200 transmits the attenuation index a calculated by the base station device 200 to the other base station device 200 that performs wireless power transmission. ０ or a １ and notifies the attenuation index a between the plurality of base station devices 200 that perform wireless power transmission. ０ and a １ The base station device 200 may compare the transmission power of the transmission signal from its own base station device 200 according to the result of the comparison. The control of the transmission power may include, for example, controlling the strength of power amplification of a power amplifier (PA: see PA111 in FIG. 2 ) included in its own base station device 200 so that the transmission power (PAPR, as an example) becomes a target transmission power. The transmission power of the transmission signal may be controlled relatively according to the relationship with the transmission power of the transmission signal from the other base station device 200.

[0123] The reference symbol D1 in FIG. 12 indicates the attenuation index a ０ and a １ 10 shows an example of the relationship between the transmission powers (denoted as PA#0 and PA#1) of the base station devices #0 and #1 according to the comparison results.

[0124] For example, distance d ０ is the distance d １ or if the quality q ０ is quality q １ If the attenuation index a of the base station device #0 is lower than ０ is the attenuation index a of the base station device #1. １In this case, it can be said that the attenuation of the transmission power of the signal transmitted by base station device #0 is greater than that of the signal transmitted by base station device #1 when the signal reaches terminal device 300. Therefore, the transmission power PA#0 of the signal transmitted from base station device #0 can be made greater than the transmission power PA#1 of the signal transmitted from base station device #1.

[0125] Also, for example, the distance d ０ and distance d １ If and are equal, or if quality q ０ and quality q １ If the attenuation index a of the base station device #0 is equal to ０ and the attenuation index a of the base station device #1 １ and are equal. Note that "equal" may include a case where the difference between the two is small, for example, equal to or less than a threshold. In this case, it can be said that the attenuation of the transmission power of the signal transmitted by base station device #0 and the signal transmitted by base station device #1 when the signals reach terminal device 300 is about the same. Therefore, it is sufficient to make the transmission power PA#0 of the signal transmitted from base station device #0 and the transmission power PA#1 of the signal transmitted from base station device #1 about the same.

[0126] Furthermore, for example, the distance d ０ is the distance d １ or if the quality q ０ is quality q １ If the attenuation index a of the base station device #0 is higher than ０ is the attenuation index a of the base station device #1. １ In this case, it can be said that the attenuation of the transmission power of the signal transmitted by base station device #0 when the signal reaches terminal device 300 is smaller than that of the signal transmitted by base station device #1. Therefore, the transmission power PA#0 of the signal transmitted from base station device #0 can be made smaller than the transmission power PA#1 of the signal transmitted from base station device #1.

[0127] As described above, the wireless communication system 1 according to the second embodiment can control the transmission power of the base station device 200 in accordance with the transmission environment between the base station device 200 and the terminal device 300. As a result, even if the transmission environment fluctuates over time, the base station device 200 can transmit the wireless power supply signal 10 that allows the terminal device 300 to obtain an appropriate PAPR_rx, thereby improving power conversion efficiency.

[0128] The base station device 200 may generate an attenuation index a at a certain timing, for example, at a periodic timing. ０ and a １ is calculated, and the decay index a ０ or a １ 12 is executed when a change (e.g., an increase or decrease of a predetermined value or a predetermined percentage) from the previous calculation result of PAPR_rx is detected. This enables the base station device 200 to transmit the wireless power supply signal 10 that can obtain an optimal PAPR_rx in accordance with (e.g., by following) a change in the transmission environment.

[0129] In addition, the wireless communication system 1 uses an attenuation index a ０ or a １ When a change from the previous calculation result of PAPR_rx is detected, the base station device 200 may perform a training process in addition to or instead of controlling the transmission power of the base station device 200. This enables the base station device 200 to transmit the wireless power supply signal 10 that can obtain an optimal PAPR_rx under the changed transmission environment.

[0130] Furthermore, the decay index a ０ and a １ The comparison of the attenuation index a and / or the control of the transmission power of the transmission signal may be performed by, for example, the base station device #0 serving as the master device. ０ and calculates the attenuation index a from the base station device #1. １ In addition, the base station device #0 may acquire the attenuation index a ０ and a １ The target transmission power of each of base station apparatuses #0 and #1 may be determined based on the comparison result, and the target transmission power of base station apparatus #1 may be notified to base station apparatus #1.

[0131] In addition, the attenuation index a ０ and a １ Although the attenuation index a is described as an index in which the larger the value, the greater the attenuation of the transmission power, and the smaller the value, the smaller the attenuation of the transmission power, it is not limited to this. ０ and a １ may be calculated as an index indicating that the larger the value, the smaller the attenuation of the transmission power, and the smaller the value, the greater the attenuation of the transmission power.

[0132] The technique according to the second example may be implemented in combination with the above-described embodiment and Example 1. For example, the wireless transmission device 110 according to the embodiment or the base station device 200 according to the first example may change the power amplification factor of the power amplifier (e.g., PA111) in response to changes in the transmission environment.

[0133] [D] Third Example Next, a third example will be described. In the embodiment, the first, and second examples, a case where two base station devices 200 transmit wireless power supply signals 10 has been described as an example. In the third example, a case where three or more base station devices 200 transmit wireless power supply signals 10 is assumed.

[0134] 13 is a diagram illustrating an example of the configuration of a wireless communication system 1 according to a third embodiment. The wireless communication system 1 may include base station devices 200A, 200B, and 200C, and a terminal device 300. The base station device 200C may have the same functional and hardware configuration as the base station devices 200A and 200B.

[0135] The base station device 200A forms a cell C10. The base station device 200B forms a cell C11. The base station device 200C forms a cell C12. The terminal device 300 is present in the cells C10, C11, and C12. In other words, the terminal device 300 is present within the coverage of each of the base station devices 200A, 200B, and 200C. The base station devices 200A, 200B, and 200C are connected to each other via a network N10 so that they can communicate with each other. In the following description, when there is no need to distinguish between the base station devices 200A, 200B, and 200C, they may be referred to as the base station device 200.

[0136] FIG. 14 is a diagram illustrating an example of a wireless power transmission technique according to a third embodiment. Hereinafter, the base station device 200C may be referred to as base station device #2. Each of base station devices #0, #1, and #2 transmits a transmission signal at a predetermined timing using at least a portion of a different frequency band. The transmission signals may be wireless power supply signals 10A, 10B, and 10C, or, if a training process is performed as in the first embodiment, training signals 12A, 12B, and 12C (not shown). In the example of FIG. 14, base station device #0 functions as a master device, and base station devices #1 and #2 function as slave devices.

[0137] For example, symbol E1 shows an example in which base station device #0 transmits a generated signal mapped to frequency bands f2 to f3 as wireless power supply signal 10A. Symbol E2 shows an example in which base station device #1 transmits a generated signal mapped to frequency bands f1 to f2 as wireless power supply signal 10B. Symbol E3 shows an example in which base station device #2 transmits a generated signal mapped to frequency bands f0 to f1 as wireless power supply signal 10C.

[0138] Each of the wireless power supply signals 10A, 10B, and 10C is received by the terminal device 300 as a composite signal 11 in, for example, frequency bands f0 to f3 (see symbol E4). This allows the wireless power supply signals 10 transmitted from three transmission points to be composited, so the wireless communication system 1 can further reduce the PAPR on the transmitting side and further increase the PAPR_rx on the receiving side, compared to a case in which power is supplied from two transmission points.

[0139] Incidentally, the technique according to the embodiment can improve the power conversion efficiency of the wireless communication system 1 by supplying power from at least two base station devices 200. For this reason, for example, the wireless communication system 1 may control a base station device 200 whose contribution to an increase in the PAPR_rx of the terminal device 300 has decreased due to a change in the transmission environment or the like to suppress (not transmit) the transmission of the wireless power supply signal 10. This makes it possible to effectively utilize the resources of the base station device 200 whose transmission of the wireless power supply signal 10 has been suppressed.

[0140] 14 shows an example in which the power of the frequency bands f0-f1 and f1-f2 in the combined signal 11 has decreased due to a change in the transmission environment, etc. The control unit 320 (or the receiving unit 312) of the terminal device 300 may calculate the received power for each divided frequency band, for example, for each of the frequency bands f0-f1, f1-f2, and f2-f3. For example, the control unit 320 may calculate the received power of each of the wireless power supply signals 10 before combining.

[0141] For example, when there is a frequency band with received power below a preset threshold, the terminal device 300 may perform control to suppress transmission of the wireless power supply signal 10 from the base station device 200 using that frequency band. An example of the preset threshold is power equivalent to noise power. Reference symbol E6 shows an example in which the terminal device 300 performs control to suppress transmission from the base station device #1 using the frequency bands f1 to f2.

[0142] The control to suppress the transmission of the wireless power supply signal 10 may include, for example, transmission of a control signal to the base station device #1. The control signal may include, for example, an instruction to stop the transmission of the wireless power supply signal 10. Note that the base station device #1 may resume the transmission of the wireless power supply signal 10 after a certain period of time has elapsed, or when the terminal device 300 detects a change in the transmission environment (for example, an improvement in the transmission environment between the base station #1 and the terminal device 300) and issues an instruction to resume the transmission by a control signal.

[0143] In addition, when the control target that suppresses the transmission of the wireless power supply signal 10 is a main device, the main device may, for example, delegate the function (authority) of the main device to one of the sub-devices in the wireless communication system 1.

[0144] As described above, according to the third embodiment, transmission of the signal 10 for wireless power supply, in other words, wireless power supply, is suppressed by a base station device 200 among the plurality of base station devices 200 that transmits the signal 10 for wireless power supply using a frequency band in which the received power at the terminal device 300 is less than a threshold. This makes it possible to effectively utilize the resources of the base station device 200 from which wireless power supply is suppressed, in other words, the wireless communication system 1, while suppressing a decrease in the power of the combined signal 11 at the terminal device 300.

[0145] Furthermore, even if an obstacle or the like appears between a certain base station device 200 and a terminal device 300, the other two base station devices 200 that are less affected by the obstacle or the like can continue to wirelessly supply power to the terminal device 300, thereby improving the stability of wireless power transmission. In other words, by providing three or more base station devices 200 as base station devices 200 that are capable of wirelessly supplying power, the wireless communication system 1 can have a redundant configuration and can flexibly respond to changes in the transmission environment.

[0146] The technique according to the third example may be implemented in combination with each of the above-described embodiments, the first example, and the second example. For example, the wireless communication system 1 according to the first example may execute the training process using three or more base station devices 200. Furthermore, the wireless communication system 1 according to the second example may change the power amplification factor of the power amplifier (e.g., PA111) of each of the three or more base station devices 200 in response to changes in the transmission environment. Furthermore, the terminal device 300 may change the power amplification factor of the power amplifier (e.g., PA111) for the base station device 200 that transmits the wireless power supply signal 10 using a frequency band in which the received power at the terminal device 300 is below a threshold.

[0147] [E] Other The techniques according to the above-described embodiment, first example, second example, and third example can be implemented with the following modifications and changes.

[0148] For example, the training process described in the first embodiment may be performed with various modifications depending on the transmission environment. As an example, the time interval at which the training process is performed may be set to a relatively long time when the change in the transmission environment is small, and may be gradually or stepwise increased, for example, when the change in the transmission environment is small. On the other hand, when the change in the transmission environment is large, the time interval at which the training process is performed may be set to a relatively short time, and may be gradually or stepwise shortened, for example, when the change in the transmission environment is large or when the power of the composite signal 11 is tending to decrease.

[0149] A change in the transmission environment may be considered, for example, as the amount of change in the attenuation index, and if the amount of change in the attenuation index is less than the lower threshold, the change in the transmission environment may be judged to be small, and if the amount of change in the attenuation index is greater than or equal to the upper threshold, the change in the transmission environment may be judged to be large.

[0150] If there is no change in the transmission environment, the training process may be executed for the first time, for example, when the base station device 200 or the terminal device 300 is started up. Alternatively, information about a generated signal determined in advance by verification in another wireless communication system may be set as the initial setting of the base station device 200 and the terminal device 300. In these cases, execution of the training process may be suppressed in the operational state.

[0151] Furthermore, the generated signal candidates included in the training signal 12 may be optimized as the training process is repeatedly executed. For example, optimization may involve selecting a predetermined number of generated signals that are most likely to be selected in past training processes as generated signal candidates to be included in the training signal 12. Furthermore, when the change in the transmission environment is small, the number (patterns) of generated signal candidates included in the training signal 12 may be reduced during optimization. On the other hand, when the change in the transmission environment is large, the number (patterns) of generated signal candidates included in the training signal 12 may be increased during optimization.

[0152] The optimization may utilize, for example, an AI (Artificial Intelligence) task using a neural network, such as inference processing using a machine learning model trained to output a generated signal suitable for an input transmission environment. The machine learning model may be generated by training (machine learning processing) using training data that accumulates combinations of various transmission environments and generated signals selected for each transmission environment.

[0153] The above-described wireless power transmission technique may be applied to wireless power supply to a vehicle such as an EV (electric vehicle), etc. As an example, a terminal device 300 provided in the vehicle may receive wireless power supply signals 10 from each of a plurality of base station devices 200 installed under the road surface of a roadway, a parking lot, etc., and output power of a composite signal 11 to a rechargeable battery of the vehicle.

[0154] 1 Wireless communication system 10, 10A, 10B, 10C Wireless power supply signal 11 Composite signal 12, 12A, 12B, 12C Training signal 100 System 110 Wireless transmitting device 111 PA 112, 121 Antenna 120 Wireless receiving device 122 Power output unit 200, 200A, 200B, 200C Base station device 210 Wireless communication unit 211, 311 Transmitter 212, 312 Receiver 220, 320 Control unit 230, 330 Storage unit 240, 310 Communication unit 300 Terminal device 410, 510 Antenna 420, 520 RF circuit 430, 530 CPU 440, 540 DSP 450, 550 Memory 460 Network IF 560 Charging circuit C10, C11, C12 Cell N10 Network

Claims

1. A receiving device comprising: a receiving unit that receives a first transmission signal transmitted in a first frequency band from a first transmission device included in a plurality of transmission devices, and a second transmission signal transmitted in a second frequency band that is at least partially different from the first frequency band from a second transmission device included in the plurality of transmission devices; and an output unit that outputs the power of a composite signal of a plurality of transmission signals including the first transmission signal and the second transmission signal.

2. The receiving device according to claim 1, wherein the receiving unit acquires the composite signal obtained by combining the plurality of transmission signals transmitted from the plurality of transmitting devices.

3. The receiving device according to claim 1, wherein the receiving unit receives a first signal including a plurality of candidates for the transmitted signal, transmitted at a first timing from each of the plurality of transmitting devices, and includes a control unit that selects one of the candidates from each of the first signals received from each of the plurality of transmitting devices.

4. The receiving device according to claim 3, further comprising a transmitting unit that transmits a control signal including information about the selected candidate to the first transmitting device of the plurality of transmitting devices.

5. The receiving device according to claim 3, wherein the first signal is a signal in which the pattern of one or both of the data and the frequency band to which the data is mapped is changed in the time domain, and the first signals transmitted by the plurality of transmitting devices are signals in which the frequency bands to which the data is mapped in the time domain have different combinations.

6. The receiving device according to claim 1, wherein the receiving unit receives the plurality of transmission signals whose transmission power is controlled according to an index relating to the transmission environment of wireless power transmission between each of the plurality of transmitting devices and the receiving device.

7. A receiving device as described in claim 5, further comprising a transmitting unit that transmits information regarding one or both of the distance and communication quality between each of the plurality of transmitting devices and the receiving device to the first transmitting device among the plurality of transmitting devices.

8. The receiving device according to claim 1, further comprising a control unit that calculates the power of each of the plurality of transmission signals and controls a transmitting device among the plurality of transmitting devices that has transmitted a transmission signal whose power is less than a threshold value to suppress transmission of the transmission signal.

9. A transmitting device comprising: a control unit that generates a first transmission signal using a first frequency band that is at least partially different from a second frequency band used for a second transmission signal that another transmitting device transmits to a receiving device at a predetermined timing; and a transmitting unit that transmits the first transmission signal to the receiving device at the predetermined timing.

10. A wireless power transmission system for wireless power transmission, comprising: a plurality of transmitting devices; and a receiving device, wherein the receiving device receives a first transmission signal transmitted in a first frequency band from a first transmitting device included in the plurality of transmitting devices, and a second transmission signal transmitted in a second frequency band that is at least partially different from the first frequency band from a second transmitting device included in the plurality of transmitting devices, and outputs power of a composite signal of the plurality of transmission signals including the first transmission signal and the second transmission signal.

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