WO2024062645A1

WO2024062645A1 - System for performing wireless power transmission, base station, method, and program

Info

Publication number: WO2024062645A1
Application number: PCT/JP2023/005195
Authority: WO
Inventors: 悠太中本; 直輝長谷川; 裕貴 ▲高▼木; 昂平川; 喜元太田
Original assignee: ソフトバンク株式会社
Priority date: 2022-09-22
Filing date: 2023-02-15
Publication date: 2024-03-28
Also published as: JP7279249B1; JP2024046254A

Abstract

Provided is a system in which the efficiency of a power amplifier for amplifying a wireless power transmission signal in a base station can be improved. In this invention, the base station generates a transmission signal including a dummy signal for wireless power transmission using radio resources not used for communication among a plurality of radio resources, and amplifies the transmission signal including a dummy signal for wireless power transmission using the power amplifier and transmits same to a terminal device. The terminal device receives the transmission signal including a wireless power transmission signal transmitted from the base station and outputs electric power of a reception signal, which is the received transmission signal including a wireless power transmission signal. The dummy signal for wireless power transmission is a modulation signal having a peak-to-average power ratio (PAPR) lower than a communication signal.

Description

System, base station, method and program for wireless power transmission

The present invention relates to a system, base station, method, and program that can perform wireless power transfer (WPT).

Conventionally, a communication system is known that performs communication between a base station and a terminal device using at least part of a plurality of radio resources set in a radio frame (for example, see Patent Document 1).

International Publication No. 2017/164220

In conventional communication systems, as a terminal device that connects to a base station and communicates, there is a portable terminal device that mainly uses power supplied from a built-in battery. This terminal device requires a complicated task of charging the built-in battery when its remaining capacity is low. Further, terminal devices that use power supplied from a wired power line instead of a built-in battery are limited to use in locations where such a power line can be used. In this way, power supply infrastructure that can supply power to various terminal devices that connect to base stations and communicate is not yet developed.

In the 5th generation and subsequent next generation mobile communication systems, it is expected that the number of terminal devices (e.g., user equipment, IoT devices, etc.) that connect to base stations and communicate will rapidly increase, and communication that will handle a huge amount of traffic will be necessary. Infrastructure development is progressing. However, the power supply infrastructure capable of supplying power to the huge number of terminal devices that perform the above communication remains underdeveloped.

A system that performs wireless power transmission (WPT) using a mobile communication base station is being considered as a power supply infrastructure that supplies power to the terminal device. One of the challenges for such a system is to increase the output and efficiency of a power amplifier when amplifying signals for wireless power transmission (WPT).

A system according to one aspect of the present invention is a system that includes a base station that can communicate by selectively using a plurality of radio resources, and performs wireless power transmission from the base station to a terminal device. The base station includes a communication signal processing unit that generates a transmission signal including a dummy signal for wireless power transmission using an unused wireless resource that is not used for communication among the plurality of wireless resources; and a wireless processing unit that amplifies a transmission signal including a dummy signal for transmission using a power amplifier and transmits the amplified signal to the terminal device. The terminal device includes a wireless processing unit that receives a transmission signal including the dummy signal transmitted from the base station, and a power output unit that outputs the power of the received signal that received the transmission signal including the dummy signal as received power. It has a section and a. The dummy signal for wireless power transmission is a modulated signal whose peak power to average power ratio (PAPR) is lower than that of the communication signal.

In the system, the output power range of the dummy signal for wireless power transmission in the power amplifier is higher than the output power range of the communication signal, and the wireless processing unit and the dummy signal for wireless power transmission so that the peak of power added efficiency (PAE) in the efficiency characteristic of the power amplifier is located at or near the upper limit of each of the output power range of the communication signal. Control may be performed to switch the efficiency characteristics of the power amplifier between when transmitting the communication signal and when transmitting the communication signal.

In the system, the power amplifier is configured with a power amplification FET, and the wireless processing unit switches efficiency characteristics of the power amplifier between when transmitting the dummy signal for wireless power transmission and when transmitting the communication signal. Furthermore, the drain voltage of the power amplification FET may be controlled.

A system according to another aspect of the present invention is a system that includes a base station capable of communicating by selectively using a plurality of radio resources, and performs wireless power transmission from the base station to a terminal device. The base station includes a communication signal processing unit that generates a transmission signal including a dummy signal for wireless power transmission using an unused wireless resource that is not used for communication among the plurality of wireless resources; and a wireless processing unit that amplifies a transmission signal including a dummy signal for transmission using a power amplifier and transmits the amplified signal to the terminal device. The terminal device includes a wireless processing unit that receives a transmission signal including the dummy signal transmitted from the base station, and a power output unit that outputs the power of the received signal that received the transmission signal including the dummy signal as received power. It has a section and a. The output power range of the dummy signal for wireless power transmission in the power amplifier is higher than the output power range of the communication signal, and the wireless processing unit At the time of transmitting the dummy signal for wireless power transmission and at the time of transmitting the dummy signal for wireless power transmission, Control is performed to switch the efficiency characteristics of the power amplifier when transmitting a communication signal.

In the system, the communication signal and the wireless power transmission dummy signal are transmitted in mutually different communication frames and wireless power transmission frames, respectively, and the wireless processing unit switches the drain voltage on a frame-by-frame basis. It may be controlled as follows.

A base station according to yet another aspect of the present invention is a base station that can communicate by selectively using a plurality of radio resources. This base station includes: a communication signal processing unit that generates a transmission signal including a dummy signal for wireless power transmission using an unused wireless resource that is not used for communication among the plurality of wireless resources; It includes a wireless processing unit that amplifies a transmission signal including a dummy signal for transmission using a power amplifier and transmits the amplified signal to a terminal device. The dummy signal for wireless power transmission is a modulated signal whose peak power to average power ratio (PAPR) is lower than that of the communication signal.

In the base station, the output power range of the dummy signal for wireless power transmission in the power amplifier is higher than the output power range of the communication signal, and the wireless processing unit is configured to output power of the dummy signal for wireless power transmission in the power amplifier. the wireless power transmission dummy so that the peak of power added efficiency (PAE) in the efficiency characteristics of the power amplifier is located at or near the upper limit of each of the range and the output power range of the communication signal; Control may be performed to switch the efficiency characteristics of the power amplifier between when transmitting a signal and when transmitting the communication signal.

In the base station, the power amplifier is configured with a power amplification FET, and the wireless processing unit switches efficiency characteristics of the power amplifier between when transmitting the dummy signal for wireless power transmission and when transmitting the communication signal. The drain voltage of the power amplification FET may be controlled in this manner.

A base station according to yet another aspect of the present invention is a base station that can communicate by selectively using a plurality of radio resources. This base station includes: a communication signal processing unit that generates a transmission signal including a dummy signal for wireless power transmission using an unused wireless resource that is not used for communication among the plurality of wireless resources; a wireless processing unit that amplifies a transmission signal including a dummy signal for transmission with a power amplifier and transmits the amplified signal to a terminal device, and the output power range of the dummy signal for wireless power transmission in the power amplifier is equal to the output of a communication signal. the efficiency of the power amplifier is higher than the power range, and the wireless processing unit sets the efficiency of the power amplifier to the upper limit or near the upper limit of each of the output power range of the dummy signal for wireless power transmission and the output power range of the communication signal. Control is performed to switch the efficiency characteristics of the power amplifier when transmitting the dummy signal for wireless power transmission and when transmitting the communication signal so that the peak of power added efficiency (PAE) in the characteristics is located.

In the base station, the communication signal and the wireless power transmission dummy signal are transmitted in mutually different communication frames and wireless power transmission frames, respectively, and the wireless processing unit calculates the drain voltage on a frame-by-frame basis. It may be controlled to switch.

A method according to yet another aspect of the present invention is a method in which a base station and a terminal device selectively use a plurality of radio resources to communicate with each other. In this method, the base station generates a transmission signal including a dummy signal for wireless power transmission using an unused radio resource that is not used for communication among the plurality of radio resources; The station amplifies the transmission signal including the dummy signal for wireless power transmission with a power amplifier and transmits the amplified signal to the terminal device, and the terminal device amplifies the transmission signal including the dummy signal transmitted from the base station. and the terminal device outputs, as received power, the power of the received signal from which the terminal device received the transmission signal including the dummy signal. The dummy signal for wireless power transmission is a modulated signal whose peak power to average power ratio (PAPR) is lower than that of the communication signal.

A method according to yet another aspect of the present invention is a method in which a base station and a terminal device selectively use a plurality of radio resources to communicate with each other. In this method, the base station generates a transmission signal including a dummy signal for wireless power transmission using an unused radio resource that is not used for communication among the plurality of radio resources; The station amplifies the transmission signal including the dummy signal for wireless power transmission with a power amplifier and transmits the amplified signal to the terminal device, and the terminal device amplifies the transmission signal including the dummy signal transmitted from the base station. and the terminal device outputs, as received power, the power of the received signal from which the terminal device received the transmission signal including the dummy signal. An output power range of the dummy signal for wireless power transmission in the power amplifier is higher than an output power range of the communication signal. Further, in this method, the base station sets efficiency characteristics of the power amplifier at or near the upper limit of each of the output power range of the dummy signal for wireless power transmission and the output power range of the communication signal. further comprising performing control to switch efficiency characteristics of the power amplifier when transmitting the dummy signal for wireless power transmission and when transmitting the communication signal so that a peak of power added efficiency (PAE) is located at .

In the method, the power amplifier is configured with a power amplification FET, and the base station switches efficiency characteristics of the power amplifier between when transmitting the dummy signal for wireless power transmission and when transmitting the communication signal. , may include controlling a drain voltage of the power amplification FET.

In the method, the communication signal and the wireless power transmission dummy signal are transmitted in different communication frames and wireless power transmission frames, respectively, and the base station measures the efficiency characteristics of the power amplifier on a frame-by-frame basis. It may further include controlling to switch by.

A program according to yet another aspect of the present invention is a program executed in a computer or processor provided in a base station that selectively uses a plurality of radio resources to communicate with a terminal device. This program includes a program code for generating a transmission signal including a dummy signal for wireless power transmission using an unused wireless resource that is not used for communication among the plurality of wireless resources, and the wireless power transmission. and a program code for amplifying a transmission signal including a dummy signal for use with a power amplifier and transmitting the amplified signal to the terminal device. The dummy signal for wireless power transmission is a modulated signal whose peak power to average power ratio (PAPR) is lower than that of the communication signal.

A program according to yet another aspect of the present invention is a program executed in a computer or processor provided in a base station that selectively uses a plurality of radio resources to communicate with a terminal device. This program includes a program code for generating a transmission signal including a dummy signal for wireless power transmission using an unused wireless resource that is not used for communication among the plurality of wireless resources, and the wireless power transmission. and a program code for amplifying a transmission signal including a dummy signal for use with a power amplifier and transmitting the amplified signal to the terminal device. An output power range of the dummy signal for wireless power transmission in the power amplifier is higher than an output power range of the communication signal. This program sets power added efficiency (PAE) in the efficiency characteristics of the power amplifier at or near the upper limit of each of the output power range of the dummy signal for wireless power transmission and the output power range of the communication signal. The power amplifier further includes a program code for performing control to switch efficiency characteristics of the power amplifier between when transmitting the dummy signal for wireless power transmission and when transmitting the communication signal so that a peak of is located.

In the program, the power amplifier is configured with a power amplification FET, and the power amplifier is configured to switch efficiency characteristics of the power amplifier between when transmitting the dummy signal for wireless power transmission and when transmitting the communication signal. Program code may also be included to control the drain voltage of the FET.

In the program, the communication signal and the wireless power transmission dummy signal are transmitted in different communication frames and wireless power transmission frames, respectively, and the efficiency characteristics of the power amplifier are controlled to be switched on a frame-by-frame basis. It may further include program code for.

The program includes a trained model used for machine learning.

According to the present invention, it is possible to increase the output and efficiency of a power amplifier when amplifying a signal for wireless power transmission in a base station.

FIG. 1 is an explanatory diagram showing an example of the overall configuration of a system according to an embodiment. FIG. 2 is a block diagram illustrating an example of the configuration of a base station and a terminal device that constitute the system according to the embodiment. FIG. 3A is an explanatory diagram illustrating an example of allocation of WPT blocks in radio resources (resource blocks) of transmission signals including WPT dummy signals transmitted from the base station according to the embodiment. FIG. 3B is an explanatory diagram showing an example of a spectrum on the frequency axis in OFDM secondary modulation of a transmission signal transmitted from a base station according to the embodiment. FIG. 4 is a graph showing an example of input/output power characteristics and efficiency characteristics of the power amplifier of the base station according to the present embodiment. FIG. 5A is an explanatory diagram illustrating an example of arrangement of symbol points in QAM primary modulation of a communication signal transmitted from a base station according to the embodiment. FIG. 5B is an explanatory diagram showing an example of an arrangement of symbol points in the modulation of a dummy signal for WPT transmitted from the base station. FIG. 6 is a graph showing an example of complementary cumulative distribution function (CCDF) curves of the communication signal and the WPT dummy signal transmitted from the base station according to the embodiment. FIG. 7 is a graph showing an example of efficiency characteristics of the power amplifier when amplifying each of the communication signal and the WPT dummy signal transmitted from the base station according to the embodiment. FIG. 8 is a time chart showing an example of controlling the drain voltage of the power amplifier of the base station according to the embodiment. FIG. 9 is an explanatory diagram illustrating an example of power feeding to each terminal device by beamforming from a base station to a plurality of terminal devices according to the embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The system according to the embodiment described in this specification is a system capable of wireless power transmission (WPT) from a mobile communication base station to a terminal device (e.g., a mobile communication UE (mobile station) or an IoT device) to be powered. The system according to the embodiment is a system that effectively utilizes unused wireless resources (resource blocks) that are not used for communication among a plurality of wireless resources (resource blocks) set in a downlink wireless frame to a terminal device such as a UE, for wireless power transmission (WPT) to the terminal device. The system according to the embodiment may be a wireless communication system between a base station and a terminal device having a wireless power transmission (WPT) function from the base station to the terminal device. The system according to the embodiment may also be a wireless power transmission (WPT) system from a base station to a terminal device having a wireless communication function between the base station and the terminal device.

In particular, in the system of this embodiment, a modulated signal with a lower PAPR (peak-to-average power ratio) is used as the wireless power transmission (WPT) signal than the communication signal, and the drain voltage when amplifying the wireless power transmission (WPT) signal with a power amplifier (transmitting amplifier) made of FET is controlled to be higher than that of the communication signal, thereby achieving high output and high efficiency of the power amplifier when amplifying the wireless power transmission (WPT) signal at the base station.

FIG. 1 is an explanatory diagram showing an example of a schematic configuration of a system according to the present embodiment. The system of the present embodiment includes a cellular base station 10 that forms a communication area (cell) 10A, and is capable of wirelessly communicating with the base station 10 by connecting to the base station 10 when located in the communication area 10A. It has a terminal device (hereinafter also referred to as "UE" (user equipment)) 20 to which power is supplied.

UE20 may be a mobile station in a mobile communication system, or may be a combination of a communication device (e.g., a mobile communication module) and various devices. UE20 is equipped with, for example, an array antenna having multiple antenna elements. UE20 may be an IoT device (also called "IoT equipment").

In FIG. 1, a base station 10 is equipped with a plurality of array antennas 110 having a large number of antenna elements, and can perform communication using a massive MIMO (hereinafter also referred to as "mMIMO") transmission method with a plurality of UEs 20. . mMIMO is a wireless transmission technology that achieves high-capacity, high-speed communication by transmitting and receiving data using the array antenna 110. Furthermore, communication can be performed using an MU (Multi User)-MIMO transmission method that performs beamforming to form beams 10B in time division or simultaneously for each of the plurality of UEs 20. By performing MU-MIMO transmission using a multi-element array antenna, it is possible to direct and communicate an appropriate beam to each UE 20 according to the communication environment of each UE 20, thereby improving the communication quality of the entire cell. Moreover, since communication with a plurality of UEs 20 can be performed using the same radio resource (time/frequency resource), system capacity can be expanded.

Further, in FIG. 1, a part of the communication area 10A is a wireless power transmission area (hereinafter referred to as "WPT area") 10A' where wireless power transmission is performed from the base station 10 to the terminal device 20. The WPT area 10A' may be a smaller area than the communication area 10A as shown in the figure, or may be an area having the same or approximately the same size and position as the communication area 10A.

In the WPT area 10A', unused radio resources (resource blocks) that are not used for communication among resource blocks that are a plurality of radio resources (time/frequency resources) constituting a downlink radio frame from the base station 10 are ) is used as a wireless power transmission block. In the downlink radio frame to the UE 20, the base station 10 sends a dummy signal for wireless power transmission (hereinafter also referred to as "WPT dummy signal") to a wireless power transmission block (WPT block), which is a wireless resource that is not used for communication. ) is generated and transmitted to the UE 20.

In particular, in 5th generation or later generation mobile communication systems, a technology called lean carrier has been proposed in which the minimum necessary reference signals (RS) and control signals are placed only on some subcarriers of a radio frame. Therefore, it is expected that wireless power transmission to the UE 20 will be performed by effectively utilizing the unused radio resources in the radio frame.

The radio waves of communication signals transmitted and received between the base station 10 and the UE 20 and the radio waves of the transmission signal to which the WPT dummy signal is assigned are transmitted from the base station 10 to the UE 20, for example, are millimeter waves or microwaves.

FIG. 2 is a block diagram showing an example of the main configuration of a base station 10 and a terminal device (UE) 20 that constitute a system according to an embodiment. The base station 10 includes a base station device 100 and an antenna 110. The antenna 110 is, for example, an array antenna having a large number of antenna elements as shown in FIG. 1. There may be a single antenna 110 or multiple antennas 110. For example, multiple antennas 110 may be arranged to correspond to multiple sector cells.

The base station device 100 includes a communication signal processing section 120 and a wireless processing section 130. The communication signal processing unit 120 processes signals such as various user data and control information transmitted and received with the UE 20.

In addition, during downlink communication to the UE 20, the communication signal processing unit 120 transmits a downlink including a WPT dummy signal using an unused radio resource that is not used for communication among the plurality of radio resources. Generate a signal. For example, the WPT dummy signal can be generated by modulating with a modulation method that has a smaller PAPR (peak power to average power ratio) (also referred to as "wave height ratio") than the communication signal. For example, the WPT dummy signal may be a modulated signal that is modulated using a Zadoff-Chu sequence code and has a constant amplitude and a phase that changes over time, or may be a modulated signal that is modulated using a Zadoff-Chu code, and may be a modulated signal that has a constant amplitude and a phase that changes over time. The signal may be a signal modulated at one or more symbol points having the maximum amplitude or near the maximum amplitude. For example, the transmission signal generation uses primary modulation such as QAM (quadrature amplitude modulation) for communication signals and modulation with small PAPR for WPT dummy signals, and secondary modulation such as OFDM (orthogonal frequency division multiplexing) modulation. May include.

The radio processing unit 130 transmits the transmission signal generated by the communication signal processing unit 120 from the antenna 110 to the UE 20, and outputs the reception signal received from the UE 20 via the antenna 110 to the communication signal processing unit 120.

The wireless processing unit 130 includes a power amplifier (transmission amplifier) 131 that amplifies the power of a transmission signal, and a control unit 132 that controls the power amplifier 131. The power amplifier 131 can be configured using, for example, a high frequency/high power FET. For example, the control unit 132 controls the drain voltage (DC voltage) applied to the power amplifier 131 so as to switch the efficiency characteristics of the power amplifier 131 made of FET between when amplifying a communication signal and when amplifying a WPT dummy signal. control.

The process of including a WPT dummy signal using unused radio resources in the transmission signal of downlink communication to the UE 20 and the control of the drain voltage of the power amplifier 131 are performed for each subframe that constitutes the radio frame of mobile communication. You may go.

Further, the base station 10 may autonomously perform the process of including a WPT dummy signal using unused radio resources in the transmission signal of the downlink communication to the UE 20, or the process may be performed by the base station 10 autonomously, or upon request or instruction from the UE 20, or It may also be performed based on a request or instruction from an external platform (eg, server, cloud system).

Furthermore, in this embodiment, the wireless processing unit 130 controls one or more beams formed by the array antenna 110 based on the BF control signal. Furthermore, the radio processing unit 130 transmits a downlink transmission signal including the WPT dummy signal generated by the communication signal processing unit 120 to the UE 20 via the antenna 110.

During downlink communication to the UE 20, the base station 10 performs beamforming (BF) control to form individual beams 10B for each UE 20 or for each UE group in the target area to which a plurality of UEs 20 belong. Wireless power transfer may be performed separately or for each UE group. BF control for each UE 20 or for each UE group may be performed by digital BF control in the frequency domain in the communication signal processing section 120, or by analog BF control in the radio processing section 130.

In FIG. 2, the UE 20 includes an antenna 210, a wireless processing section 220, a communication signal processing section 230, a power output section 240, and a battery 250. Antenna 210 is, for example, a small array antenna having a plurality of antenna elements. The wireless processing unit 220 transmits transmission signals such as feedback information and user data generated by the communication signal processing unit 230 from the antenna 210 to the base station 10, and transmits received signals received from the base station 10 via the antenna 210 to communication. It is also output to the signal processing section 230.

In this embodiment, the wireless processing unit 220 receives a transmission signal including a WPT dummy signal transmitted from the base station 10. Further, the power output unit 240 includes, for example, a rectifier, and outputs the power of the received signal that has received the transmission signal including the WPT dummy signal from the base station 10 as the received power for battery charging. The battery 250 can be charged by the received power output from the power output unit 240.

FIG. 3A is an explanatory diagram showing an example of allocation of WPT blocks in radio resources (resource blocks) of a transmission signal including a WPT dummy signal transmitted from the base station 10 according to the present embodiment. Further, FIG. 3B is an explanatory diagram showing an example of a spectrum on the frequency axis in OFDM secondary modulation of a transmission signal transmitted from the base station 10 according to the present embodiment. As shown in FIG. 3A, a plurality of radio resources used in downlink communication and uplink communication in the system of this embodiment are a plurality of resource blocks defined by subcarriers on the frequency axis and slots on the time axis. It is 30. Each resource block 30 has subcarriers 33 of a predetermined bandwidth that are orthogonal to each other on the frequency axis, as shown in FIG. 3B.

The resource block 30 configuring the radio resource in FIG. 3A is allocated to a plurality of consecutive subframes configuring a radio frame for mobile communication. In the illustrated example, each subframe is composed of a predetermined number (for example, 20) of resource blocks, including a communication subframe (hereinafter referred to as "communication frame") F1 and a WPT subframe (hereinafter referred to as "WPT frame"). (referred to as "frame") F2 are located alternately. The communication frame F1 includes a resource block 31 for uplink and downlink communication, and the WPT frame F2 includes a WPT resource block 32 that is cross-hatched in the figure. Among the resource blocks 31 of the communication frame F1, a plurality of uplink resource blocks are allocated to uplink communication signals of user data and communication signals of WPT feedback information from the UE 20, and a plurality of downlink resource blocks are allocated to uplink communication signals of user data and communication signals of WPT feedback information from the UE 20. These resource blocks are allocated to signals for downlink communication of user data and information. Further, a downlink WPT signal is allocated to the resource block 32 of the WPT frame F2.

FIG. 4 is a graph showing an example of the characteristics of the output power Pout [dBm] and the efficiency PAE [%] with respect to the input power Pin [dBm] of the power amplifier 131 of the base station 10 according to the present embodiment. Curve A in the figure is a simulation calculation result of AC output power Pout [dBm] with respect to AC input power Pin [dBm] of the power amplifier 131, and plotted points of "□" are measurements of output power Pout [dBm]. This is the result. In addition, curve B in the figure is a simulation calculation result of PAE (power added efficiency) [%], which is one of the index values of efficiency with respect to the input power Pin [dBm] of the power amplifier 131, and the plot of "○" The points are the measurement results of efficiency PAE [%]. Here, PAE [%] of the power amplifier 131 is defined as (Pout-Pin)/Pdc. Pdc is DC power input (applied) to the power amplifier 131. Furthermore, the linear region in the figure is a region where the relationship between input power Pin and output power Pout is linear or nearly linear. The saturated region in the figure is a region where the output power Pout is saturated or almost saturated with respect to an increase in the input power Pin. The peak of the efficiency PAE of the power amplifier 131 is located near the boundary between the linear region and the saturation region.

When the base station 10 amplifies a communication signal consisting of a modulated signal with a high PAPR (Peak to Average Power Ratio) using the power amplifier 131, the low output power and low efficiency linear region of the power amplifier 131 is used. For example, the operating parameters (e.g., drain voltage) of the power amplifier 131 are set so that the average power of the communication signal (modulated signal) is located at a point (center of the linear region) that is backed off appropriately to the low power side from the start point (left end) of the saturation region in Figure 4.

On the other hand, in wireless power transmission (WPT), there is a problem of wanting to amplify a dummy signal for WPT in a region of high output power and high efficiency.

Therefore, in this embodiment, in order to amplify the WPT dummy signal in the high output power and high efficiency region of the power amplifier 131, the WPT dummy signal has a PAPR (peak power to average power ratio) higher than that of the communication signal. A low OFDM modulation signal is used.

FIG. 5A is an explanatory diagram showing an example of arrangement of symbol points 41 in QAM primary modulation of a communication signal transmitted from the base station 10 according to the present embodiment. FIG. 5A is a diagram of a constellation showing the arrangement of a plurality of symbol points (64-value symbol points) in the case of the 64QAM method. Further, FIG. 5B is an explanatory diagram showing an example of arrangement of symbol points in modulation of the WPT dummy signal transmitted from the base station 10 according to the present embodiment. In FIGS. 5A and 5B, the horizontal axis shows in-phase channel components, and the vertical axis shows orthogonal channel components.

In this embodiment, an OFDM modulated signal with a lower PAPR (peak power to average power ratio) than the communication signal is used as the WPT dummy signal. For example, in FIG. 5A, among the plurality of symbol points 41 of the QAM system for communication signals, the WPT signal is composed of an OFDM modulated signal modulated only at the outermost or peripheral symbol points 41S having the maximum amplitude. A dummy signal may also be used.

Also, as shown in the constellation diagram of FIG. 5B, a dummy signal for WPT may be used that is an OFDM modulated signal modulated at symbol point 42 where the phase changes with a constant amplitude over time. The OFDM modulated signal at symbol point 42 in FIG. 5B can be generated using, for example, a code of the Zadoff-Chu sequence.

FIG. 6 is a graph showing an example of complementary cumulative distribution function (CCDF) curves of a communication signal and a WPT dummy signal transmitted from base station 10 according to this embodiment. The horizontal axis of FIG. 6 is the power level [dB] of a signal that exceeds the average power of the entire signal, and the vertical axis is the percentage [%] of time that a signal of each power level exists. Curve C11 in the figure is a CCDF curve of a communication signal (OFDM modulated signal), whose PAPR (peak-to-average power ratio) is about 10 to 12 dB. Curve C12 in the figure is a CCDF curve of a WPT dummy signal (OFDM modulated signal), whose PAPR is about 3 dB lower than that of the communication signal.

As shown in FIG. 6, by using a WPT dummy signal having a lower PAPR than the communication signal, the range of the output power Pout of the power amplifier 131 when amplifying the WPT dummy signal can be increased by using the WPT dummy signal when amplifying the communication signal. The efficiency (PAE) of the power amplifier 131 can be set in a high output power range near its peak. Therefore, communication signals can be amplified within a low output power range with a high margin so as not to generate spurious signals, and the power amplifier 131 can have high output and high efficiency when amplifying the WPT dummy signal. be able to.

Note that in this embodiment, the peak of power added efficiency (PAE:) in the efficiency characteristics of the power amplifier 131 is at or near the upper limit of each of the output power range of the WPT dummy signal and the output power range of the communication signal. Control may be performed to switch the efficiency characteristics of the power amplifier 131 when transmitting the WPT dummy signal and when transmitting the communication signal so that the power amplifier 131 is located. With this control, the output power of the power amplifier 131 when amplifying the WPT dummy signal can be further increased.

FIG. 7 is a graph showing an example of efficiency characteristics of the power amplifier 131 when amplifying each of the communication signal and the WPT dummy signal transmitted from the base station according to the embodiment. The horizontal axis in the figure is the output power Pout [dBm] of the power amplifier 131, and the vertical axis is PAE (power added efficiency) indicating the efficiency of the power amplifier 131. Further, the first output power range R1 in FIG. 7 is used in the above-mentioned communication frame F1 (see FIG. 3A) that can accommodate a high PAPR (10 to 12 dB) of a communication signal. Further, the second output power range R2 on the high power side is used in the above-mentioned WPT frame F2 (see FIG. 3A) that can accommodate the low PAPR (3 dB) of the WPT dummy signal.

In FIG. 7, a first efficiency characteristic curve C21 is an efficiency characteristic when a communication signal drain voltage Vd1 is applied to the power amplifier 131 configured with an FET. This drain voltage Vd1 is set so that the output power range R1 of the communication signal is lower than the peak of the efficiency PAE of the power amplifier 131 and is located in a low output power linear range with a high margin to prevent spurious generation. controlled.

The second efficiency characteristic curve C22 is the efficiency characteristic when the drain voltage Vd2 for WPT is applied to the power amplifier 131 configured with an FET. This drain voltage Vd2 is such that the output power range R2 for the WPT signal, which is higher than the output power range R1 of the communication signal, is in the output power range slightly lower than the peak of the efficiency PAE of the power amplifier 131, or in the output power range near the peak. The drain voltage Vd1 for the communication signal is controlled to be higher than the drain voltage Vd1 for the communication signal.

In this way, by controlling the drain voltage applied to the power amplifier 131 between the time of amplifying the communication signal and the time of amplifying the WPT dummy signal, the drain voltage applied to the power amplifier 131 is set to a low level with a high margin to prevent the generation of spurious signals for the communication signal. The power amplifier 131 can be amplified within the range of output power, and the output power and efficiency of the power amplifier 131 can be increased when amplifying the WPT dummy signal. In particular, when amplifying the WPT dummy signal, the peak of the efficiency PAE of the power amplifier 131 can be shifted to the high output power side, so that both higher output and higher efficiency can be achieved.

FIG. 8 is a time chart showing an example of controlling the drain voltage of the power amplifier 131 of the base station 10 according to the embodiment. As shown in FIG. 8, control of the drain voltage for increasing the output and efficiency of the power amplifier 131 may be performed for each frame of mobile communication (frame unit). For example, in FIG. 8, in the communication frame F1 for amplifying a communication signal, the drain voltage of the power amplifier 131 is controlled to the first drain voltage Vd1 for the communication signal. On the other hand, in the WPT frame F2 that amplifies the WPT dummy signal, the drain voltage of the power amplifier 131 is controlled to be switched to a second drain voltage Vd2 higher than the first drain voltage Vd1 for communication signals.

By controlling the drain voltage of the power amplifier 131 frame by frame in this way, it is possible to synchronize the drain voltage, compared to envelope tracking technology that constantly controls the drain voltage of the power amplifier in accordance with the output power. Control becomes easier and the implementation circuit for control becomes simpler.

According to the systems of FIGS. 1 to 8 having the above configuration, in downlink communication from the base station 10 to the UE 20, unused radio resources are effectively used as wireless power transfer blocks (WPT blocks), and from the base station 10 to the UE 20. Wireless power transfer (WPT) to the UE 20 can be performed. Furthermore, it is possible to increase the output and efficiency of the power amplifier 131 when amplifying the WPT dummy signal in the base station 10.

FIG. 9 is an explanatory diagram showing an example of power feeding to each UE by beamforming from the base station 10 to a plurality of UEs 20 according to the present embodiment. In this embodiment, as shown in FIG. 9, a plurality of UEs 20(1) to 20(3) are located in a WPT area 10A' (see FIG. 1 described above) within a communication area 10A, and a beam formed by each UE is provided. Power may be supplied to each UE 20(1) to 20(3) via 10B(1) to 10B(3). The beams 10B(1) to 10B(3) may be formed, for example, by being switched in a time-division manner.

As described above, according to this embodiment, by using a dummy signal for WPT that has a lower PAPR than the communication signal, the communication signal can be amplified in the base station 10 within a low output power range with a large margin to prevent spurious signals from occurring, and the power amplifier 131 can be made to have a high output and high efficiency when amplifying the dummy signal for WPT.

Further, according to the present embodiment, by controlling the efficiency characteristics of the power amplifier 131 (drain voltage control) when transmitting the WPT dummy signal and transmitting the communication signal, the power when amplifying the WPT dummy signal is The output power of amplifier 131 can be further increased.

Furthermore, according to the present embodiment, the drain voltage of the power amplifier 131 is controlled frame by frame (frame by frame), which is compared to envelope tracking technology in which the drain voltage of the power amplifier is constantly controlled in accordance with the output power. Therefore, the synchronous control of the drain voltage becomes easier, and the mounting circuit for control becomes simpler.

Furthermore, according to the present embodiment, power can be supplied to the terminal device 20 by using wireless resources that are not used for communication between the base station 10 and the terminal device 20.

The present invention can also provide a power supply infrastructure capable of supplying power to a large number of terminal devices 20 capable of receiving radio waves transmitted from a base station 10, thereby contributing to the achievement of Goal 9 of the Sustainable Development Goals (SDGs), which is to "build resilient infrastructure, promote inclusive and sustainable industrialization, and promote innovation and infrastructure."

Note that the processing steps and components of the system, terminal device (UE, IoT device), base station, mobile station, relay device, and control device described in this specification can be implemented by various means. For example, these steps and components may be implemented in hardware, firmware, software, or a combination thereof.

Regarding hardware implementation, in order to realize the above steps and components in entities (e.g., various wireless communication devices, base station devices (Node B, Node G), terminal devices, hard disk drive devices, or optical disk drive devices) The processing unit or other means used may be one or more of an application specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processor (DSPD), a programmable logic device (PLD), a field programmable a gate array (FPGA), processor, controller, microcontroller, microprocessor, electronic device, other electronic unit, computer, or combination thereof designed to perform the functions described herein; It may be implemented inside.

Additionally, for firmware and/or software implementations, the means used to implement the components described above, such as processing units, may include programs (e.g., procedures, functions, modules, instructions) that perform the functions described herein. , etc.). In general, any computer/processor readable medium tangibly embodying firmware and/or software code, such as a processing unit, may be used to implement the above steps and components described herein. It may be used for implementation. For example, the firmware and/or software code may be stored in memory and executed by a computer or processor, eg, in a controller. The memory may be implemented within the computer or processor, or external to the processor. The firmware and/or software code may also be stored in, for example, random access memory (RAM), read-only memory (ROM), non-volatile random access memory (NVRAM), programmable read-only memory (PROM), electrically erasable PROM (EEPROM), etc. ), flash memory, floppy disks, compact disks (CDs), digital versatile disks (DVDs), magnetic or optical data storage devices, etc. good. The code may be executed by one or more computers or processors and may cause the computers or processors to perform certain aspects of the functionality described herein.

Additionally, the medium may be a non-temporary recording medium. Further, the code of the program may be read and executed by a computer, processor, or other device or apparatus, and its format is not limited to a specific format. For example, the code of the program may be a source code, an object code, or a binary code, or may be a mixture of two or more of these codes.

The description of the embodiments disclosed herein is also provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

10: Base station 10A: Communication area 10A': WPT area 10B: Beam 20: Terminal equipment (UE)
100: Base station device 110: Antenna (array antenna)
120: Communication signal processing section 130: Radio processing section 131: Power amplifier 132: Control section 210: Antenna (array antenna)
230: Communication signal processing section 240: Power output section 250: Battery

Claims

A system comprising a base station capable of communicating by selectively using a plurality of radio resources, and performing wireless power transmission from the base station to a terminal device,
The base station is
a communication signal processing unit that generates a transmission signal including a dummy signal for wireless power transmission using an unused radio resource that is not used for communication among the plurality of radio resources;
a wireless processing unit that amplifies a transmission signal including the dummy signal for wireless power transmission with a power amplifier and transmits the amplified signal to the terminal device,
The terminal device is
a wireless processing unit that receives a transmission signal including the dummy signal transmitted from the base station;
a power output unit that outputs the power of the received signal that has received the transmitted signal including the dummy signal as received power;
The dummy signal for wireless power transmission is a modulated signal whose peak power to average power ratio (PAPR) is lower than that of the communication signal.
A system characterized by:
The system of claim 1,
The output power range of the dummy signal for wireless power transmission in the power amplifier is higher than the output power range of the communication signal,
The wireless processing unit may set power added efficiency (in the efficiency characteristics of the power amplifier) at or near the upper limit of each of the output power range of the dummy signal for wireless power transmission and the output power range of the communication signal. performing control to switch the efficiency characteristics of the power amplifier when transmitting the dummy signal for wireless power transmission and when transmitting the communication signal so that the peak of PAE) is located;
A system characterized by:
The system of claim 1,
The power amplifier is composed of a power amplification FET,
The wireless processing unit controls the drain voltage of the power amplification FET so as to switch the efficiency characteristics of the power amplifier between when transmitting the dummy signal for wireless power transmission and when transmitting the communication signal.
A system characterized by:
A system including a base station capable of communicating by selectively using a plurality of wireless resources, and performing wireless power transmission from the base station to a terminal device,
The base station,
a communication signal processing unit that generates a transmission signal including a dummy signal for wireless power transmission using an unused wireless resource that is not used for communication among the plurality of wireless resources;
a wireless processing unit that amplifies a transmission signal including a dummy signal for wireless power transmission by a power amplifier and transmits the amplified transmission signal to the terminal device,
The terminal device
a radio processing unit that receives a transmission signal including the dummy signal transmitted from the base station;
a power output unit that outputs, as received power, the power of a received signal that has received a transmission signal including the dummy signal;
an output power range of the dummy signal for wireless power transmission in the power amplifier is higher than an output power range of a communication signal;
the wireless processing unit performs control to switch efficiency characteristics of the power amplifier between when transmitting the dummy signal for wireless power transmission and when transmitting the communication signal so that a peak of a power added efficiency (PAE) in the efficiency characteristics of the power amplifier is located at or near the upper limit of each of an output power range of the dummy signal for wireless power transmission and an output power range of the communication signal.
A system characterized by:
The system of claim 4,
The power amplifier is composed of a power amplification FET,
The wireless processing unit controls the drain voltage of the power amplification FET so as to switch the efficiency characteristics of the power amplifier between when transmitting the dummy signal for wireless power transmission and when transmitting the communication signal.
A system characterized by:
The system according to claim 3 or 5,
The communication signal and the wireless power transmission dummy signal are transmitted in mutually different communication frames and wireless power transmission frames, respectively,
The wireless processing unit controls the drain voltage to be switched on a frame-by-frame basis.
A system characterized by:
A base station capable of communicating by selectively using a plurality of radio resources,
a communication signal processing unit that generates a transmission signal including a dummy signal for wireless power transmission using an unused radio resource that is not used for communication among the plurality of radio resources;
a wireless processing unit that amplifies a transmission signal including the dummy signal for wireless power transmission with a power amplifier and transmits the amplified signal to a terminal device,
The dummy signal for wireless power transmission is a modulated signal having a lower peak power to average power ratio (PAPR) than the communication signal.
A base station characterized by:
The base station according to claim 7,
The output power range of the dummy signal for wireless power transmission in the power amplifier is higher than the output power range of the communication signal,
The wireless processing unit may set power added efficiency (in the efficiency characteristics of the power amplifier) at or near the upper limit of each of the output power range of the dummy signal for wireless power transmission and the output power range of the communication signal. performing control to switch the efficiency characteristics of the power amplifier when transmitting the dummy signal for wireless power transmission and when transmitting the communication signal so that the peak of PAE) is located;
A base station characterized by:
The base station according to claim 8,
The power amplifier is composed of a power amplification FET,
The wireless processing unit controls the drain voltage of the power amplification FET so as to switch the efficiency characteristics of the power amplifier between when transmitting the dummy signal for wireless power transmission and when transmitting the communication signal.
A base station characterized by:
A base station capable of communicating by selectively using a plurality of radio resources,
a communication signal processing unit that generates a transmission signal including a dummy signal for wireless power transmission using an unused radio resource that is not used for communication among the plurality of radio resources;
a wireless processing unit that amplifies a transmission signal including the dummy signal for wireless power transmission with a power amplifier and transmits the amplified signal to a terminal device,
The output power range of the dummy signal for wireless power transmission in the power amplifier is higher than the output power range of the communication signal,
The wireless processing unit may set power added efficiency (in the efficiency characteristics of the power amplifier) at or near the upper limit of each of the output power range of the dummy signal for wireless power transmission and the output power range of the communication signal. performing control to switch the efficiency characteristics of the power amplifier when transmitting the dummy signal for wireless power transmission and when transmitting the communication signal so that the peak of PAE) is located;
A base station characterized by:
The base station according to claim 10,
The power amplifier is composed of a power amplification FET,
The wireless processing unit controls the drain voltage of the power amplification FET so as to switch the efficiency characteristics of the power amplifier between when transmitting the dummy signal for wireless power transmission and when transmitting the communication signal.
A base station characterized by:
The base station according to claim 9 or 11,
The communication signal and the wireless power transmission dummy signal are transmitted in mutually different communication frames and wireless power transmission frames, respectively,
The wireless processing unit controls the drain voltage to be switched on a frame-by-frame basis.
A base station characterized by:
A method in which a base station and a terminal device communicate with each other by selectively using a plurality of radio resources, the method comprising:
The base station generates a transmission signal including a dummy signal for wireless power transmission using an unused wireless resource that is not used for communication among the plurality of wireless resources;
The base station amplifies the transmission signal including the dummy signal for wireless power transmission with a power amplifier and transmits the amplified signal to the terminal device;
the terminal device receiving a transmission signal including the dummy signal transmitted from the base station;
The terminal device outputs, as received power, power of a received signal that has received a transmitted signal including the dummy signal,
The dummy signal for wireless power transmission is a modulated signal having a lower peak power to average power ratio (PAPR) than the communication signal.
How to characterize that.
A method in which a base station and a terminal device communicate with each other by selectively using a plurality of radio resources, the method comprising:
The base station generates a transmission signal including a dummy signal for wireless power transmission using an unused wireless resource that is not used for communication among the plurality of wireless resources;
The base station amplifies the transmission signal including the dummy signal for wireless power transmission with a power amplifier and transmits the amplified signal to the terminal device;
the terminal device receiving a transmission signal including the dummy signal transmitted from the base station;
The terminal device outputs, as received power, power of a received signal that has received a transmitted signal including the dummy signal,
The output power range of the dummy signal for wireless power transmission in the power amplifier is higher than the output power range of the communication signal,
The base station sets power added efficiency (PAE) in the efficiency characteristics of the power amplifier at or near the upper limit of each of the output power range of the dummy signal for wireless power transmission and the output power range of the communication signal. ), further comprising performing control to switch the efficiency characteristics of the power amplifier when transmitting the dummy signal for wireless power transmission and when transmitting the communication signal so that the peak of
How to characterize that.
The method of claim 14,
The power amplifier is composed of a power amplification FET,
The base station controls the drain voltage of the power amplification FET so as to switch the efficiency characteristics of the power amplifier between when transmitting the dummy signal for wireless power transmission and when transmitting the communication signal. ,
How to characterize that.
The method of claim 15,
The communication signal and the wireless power transmission dummy signal are transmitted in mutually different communication frames and wireless power transmission frames, respectively,
The base station further includes controlling the efficiency characteristic of the power amplifier to be switched on a frame-by-frame basis.
A method characterized by:
A program executed on a computer or processor included in a base station that selectively uses a plurality of radio resources to communicate with a terminal device,
A program code for generating a transmission signal including a dummy signal for wireless power transmission using an unused wireless resource that is not used for communication among the plurality of wireless resources;
a program code for amplifying a transmission signal including the dummy signal for wireless power transmission with a power amplifier and transmitting it to the terminal device,
The dummy signal for wireless power transmission is a modulated signal having a lower peak power to average power ratio (PAPR) than the communication signal.
A program characterized by:
A program executed on a computer or processor included in a base station that selectively uses a plurality of radio resources to communicate with a terminal device,
A program code for generating a transmission signal including a dummy signal for wireless power transmission using an unused wireless resource that is not used for communication among the plurality of wireless resources;
a program code for amplifying a transmission signal including the dummy signal for wireless power transmission with a power amplifier and transmitting it to the terminal device,
The output power range of the dummy signal for wireless power transmission in the power amplifier is higher than the output power range of the communication signal,
A peak of power added efficiency (PAE) in the efficiency characteristics of the power amplifier is located at or near the upper limit of each of the output power range of the dummy signal for wireless power transmission and the output power range of the communication signal. further comprising a program code for performing control to switch efficiency characteristics of the power amplifier between when transmitting the dummy signal for wireless power transmission and when transmitting the communication signal,
A program characterized by:
The program according to claim 18,
The power amplifier is composed of a power amplification FET,
A program code for controlling the drain voltage of the power amplification FET so as to switch the efficiency characteristics of the power amplifier between when transmitting the dummy signal for wireless power transmission and when transmitting the communication signal,
A program characterized by:
In the program of claim 19,
The communication signal and the wireless power transmission dummy signal are transmitted in mutually different communication frames and wireless power transmission frames, respectively,
further comprising a program code for controlling efficiency characteristics of the power amplifier to be switched on a frame-by-frame basis;
A program characterized by: