Power amplifier circuit, transmitter, base station and system

Abstract

A power amplifier circuit that can be configured with a single circuit module and that can amplify a plurality of signals separated on the time axis with desired input / output power characteristics is provided. [Solution] The power amplifier circuit comprises an outphasing amplifier having a first amplifier that amplifies a first signal having a first phase generated from a signal to be amplified, a second amplifier that amplifies a second signal having a second phase different from the first phase generated from the signal to be amplified, and a Shereigh combiner including a reactance compensation circuit arranged between the output path of the first amplifier and the output path of the second amplifier, and means for adjusting the susceptance value of the reactance compensation circuit in the Shereigh combiner in accordance with the desired input / output power characteristics of the signal to be amplified.

Description

[Technical Field]

[0001] The present disclosure relates to a power amplifier circuit that amplifies multiple signals including communication signals and signals for wireless power transmission (WPT), as well as a transmitter, a base station, and a system that include the power amplifier circuit. [Background technology]

[0002] In mobile communication systems, terminal devices that connect to base stations for communication include portable terminal devices that primarily use power supplied from an internal battery. These terminal devices require the cumbersome task of charging the internal battery when the remaining battery power is low. Furthermore, terminal devices that use power supplied from a wired power line rather than an internal battery are limited to use in locations where such a power line is available. Thus, a power supply infrastructure capable of supplying power to various terminal devices that connect to base stations for communication has yet to be developed.

[0003] In next-generation mobile communication systems, such as the fifth generation (5G) and the subsequent sixth generation (6G), a rapid increase in terminal devices (e.g., user devices, IoT devices, etc.) that connect to base stations and communicate is expected, and efforts are underway to develop communication infrastructures that can handle the massive amounts of traffic. However, a power supply infrastructure capable of supplying power to the massive number of terminal devices that will communicate as described above remains underdeveloped.

[0004] The applicant of the present application has proposed a system that can perform wireless power transmission (WPT) to a terminal device by transmitting a wireless power transmission signal (a dummy signal for wireless power transmission) to the terminal device from a mobile communication base station that performs uplink and downlink communication with the terminal device (see References 1, 2, 3, and 4). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2023-056738 [Patent Document 2] Japanese Patent Publication No. 2024-046006 [Patent Document 3] Japanese Patent Application Publication No. 2024-038686 [Patent Document 4] Japanese Patent Application Publication No. 2024-046254 Summary of the Invention

[0006] A power amplifier circuit according to one embodiment of the present disclosure comprises an outphasing amplifier having a first amplifier that amplifies a first signal having a first phase generated from a signal to be amplified, a second amplifier that amplifies a second signal having a second phase different from the first phase generated from the signal to be amplified, and a Shereigh combiner including a reactance compensation circuit arranged between an output path of the first amplifier and an output path of the second amplifier, and means for adjusting the magnitude of the susceptance of the reactance compensation circuit in the Shereigh combiner in accordance with the desired input / output power characteristics of the signal to be amplified.

[0007] In the power amplifier circuit, the signal to be amplified may include a first signal to be amplified and a second signal to be amplified, which are separated on a time axis and amplified in a first region and a second region having different output and efficiency input / output characteristics. The Shear combiner may include a first reactance compensation circuit and a second reactance compensation circuit having different susceptance values, and a first switch and a second switch that switch between the first reactance compensation circuit and the second reactance compensation circuit in accordance with a signal switching timing between the first signal to be amplified and the second signal to be amplified.

[0008] In the power amplifier circuit, the first reactance compensation circuit and the second reactance compensation circuit may each include a capacitive reactance element having a fixed, semi-fixed, or variable capacitive susceptance value and an inductive reactance element having a fixed, semi-fixed, or variable inductive susceptance value. The capacitive reactance element may be connectable to an output path of the first amplifier via the first switch, and the inductive reactance element may be connectable to an output path of the second amplifier via the first switch, and a node between the capacitive reactance element and the inductive reactance element may be grounded.

[0009] In the power amplifier circuit, the capacitive reactance element may be a variable capacitor or a varactor diode, and the inductive reactance element may be a variable inductor.

[0010] In the power amplifier circuit, the first amplifier and the second amplifier of the outphasing amplifier may each have a power amplifier element, an input matching circuit provided on the input side of the power amplifier element, and an output matching circuit provided on the output side of the power amplifier element.

[0011] A transmitter according to another aspect of the present disclosure includes a communication signal processing unit that generates a communication signal and a wireless power transmission signal by separating them on a time axis, and a wireless processing unit that amplifies the communication signal and the wireless power transmission signal that are generated by the communication signal processing unit by using a power amplifier circuit and transmits them to a terminal device. The power amplifier circuit of the wireless processing unit is any one of the power amplifier circuits described above, and the signal to be amplified includes the communication signal and the wireless power transmission signal that are amplified in a first region and a second region that have different output and efficiency input / output characteristics.

[0012] A base station according to yet another aspect of the present disclosure includes the transmitter, a receiver, and an antenna.

[0013] In the base station, the radio processing unit may switch between the first reactance compensation circuit and the second reactance compensation circuit in the Sherei combiner in accordance with signal timing of the communication signal and the wireless power transmission signal.

[0014] In the base station, the communication signal processing unit may detect the communication signal and the wireless power transmission signal, and output a trigger signal corresponding to a signal switching timing between the communication signal and the wireless power transmission signal. The wireless processing unit may switch between the first reactance compensation circuit and the second reactance compensation circuit based on the trigger signal output from the communication signal processing unit, in accordance with the signal timing of the communication signal and the wireless power transmission signal, so as to use the first reactance compensation circuit when amplifying the communication signal and the second reactance compensation circuit when amplifying the wireless power transmission signal.

[0015] In the base station, the radio processing unit may adjust a magnitude of susceptance of the first reactance compensation circuit in accordance with a peak-to-average power ratio (PAPR) for the communication signal, and adjust a magnitude of susceptance of the second reactance compensation circuit in accordance with a peak-to-average power ratio (PAPR) for the wireless power transmission signal.

[0016] In the base station, the communication signal processing unit may detect the communication signal and the wireless power transmission signal, and output a trigger signal corresponding to a signal switching timing between the communication signal and the wireless power transmission signal, and the wireless processing unit may switch the input-side and output-side bias voltages and the input-side and output-side matching circuits in accordance with the signal timing of the communication signal and the wireless power transmission signal, based on the trigger signal output from the communication signal processing unit, so as to use bias voltages for input-side communication and output-side communication and matching circuits for input-side communication and output-side communication when amplifying the communication signal, and to use bias voltages for input-side wireless power transmission and output-side wireless power transmission and matching circuits for input-side wireless power transmission and output-side wireless power transmission when amplifying the wireless power transmission signal.

[0017] A system according to yet another aspect of the present disclosure is a system including any of the base stations described above, and performing communication between the base station and a terminal device and wireless power transmission from the base station to the terminal device.

[0018] The program for adjusting and setting the magnitude of the susceptance of the reactance compensation circuit in the power amplifier circuit of the present disclosure may include a pre-learning model or a trained model used in machine learning. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is an explanatory diagram illustrating an example of the overall configuration of a system according to an embodiment. [Figure 2] FIG. 2 is a block diagram showing an example of the configuration of a base station and a terminal device that constitute the system according to the embodiment. [Figure 3] 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 signal transmitted from a base station according to an embodiment. FIG. 3B is an explanatory diagram showing an example of a spectrum on the frequency axis in secondary modulation of the OFDM method of a transmission signal transmitted from a base station according to an embodiment. [Figure 4] FIG. 4 is a graph showing an example of input / output power characteristics and efficiency characteristics of a power amplifier of a base station according to this embodiment. [Figure 5] Fig. 5(a) is an explanatory diagram showing an example of the arrangement of symbol points in the primary modulation of the QAM method of a communication signal transmitted from a base station according to an embodiment. Fig. 5(b) is an explanatory diagram showing an example of the arrangement of symbol points in the modulation of a WPT signal transmitted from the same base station. [Figure 6] FIG. 6 is a block diagram illustrating an example of a configuration of a main part of a transmitter of the base station device according to the embodiment. [Figure 7]FIG. 7 is a block diagram showing an example of a configuration of a main part of a transmission signal processing unit that generates an input signal to an outphasing amplifier in a communication signal processing unit provided in a transmitter of a base station device according to the embodiment. [Figure 8] FIG. 8 is a circuit diagram showing an example of a general circuit configuration of an outphasing amplifier. [Figure 9] FIG. 9 is a graph showing an example of ideal efficiency characteristics of an outphasing amplifier. [Figure 10] 10(a) and 10(b) are graphs showing an example of a comparison of the ideal efficiency characteristics of an outphasing amplifier and a Doherty amplifier when the target back-off value is 6 dB and 12 dB, respectively. [Figure 11] 11(a) is a graph showing an example of a comparison of the estimated modulated wave power efficiency of an outphasing amplifier and a Doherty amplifier with ideal efficiency characteristics when the target back-off value is 6 dB, and FIG. 11(b) is a graph showing an example of a comparison of the estimated modulated wave power efficiency of an outphasing amplifier and a Doherty amplifier with ideal efficiency characteristics when the target back-off value is 12 dB. [Figure 12] FIG. 12 is a circuit diagram showing an example of a circuit configuration of a reactance compensation circuit adjustment type outphasing amplifier used in a transmitter of a base station according to this embodiment. [Figure 13] 13(a) and 13(b) are circuit diagrams each showing an example of a circuit configuration of a reactance compensation circuit switching type outphasing amplifier used in a transmitter of a base station according to this embodiment. [Figure 14] FIG. 14 is a block diagram showing an example of a configuration of a main part of a base station device including a transmitter having a reactance compensation circuit switching type outphasing amplifier according to the embodiment. [Figure 15] FIG. 15 is a flowchart illustrating an example of a control flow in a base station device including a transmitter having a reactance compensation circuit switching type outphasing amplifier according to the embodiment. [Figure 16] FIG. 16 is an explanatory diagram illustrating an example of a control system in a base station device including a transmitter having a reactance compensation circuit switching type outphasing amplifier according to the embodiment. [Figure 17] Fig. 17(a) is a circuit diagram showing an example of a variable capacitor, and Fig. 17(b) is a circuit diagram showing another example of a variable capacitor. [Figure 18] Fig. 18(a) is a circuit diagram showing an example of a variable inductor, and Fig. 18(b) is a circuit diagram showing another example of a variable inductor. [Figure 19] FIG. 19 is a circuit diagram showing an example of a circuit configuration (equivalent circuit) of a Shelay combiner in a reactance compensation circuit switching type outphasing amplifier used in a transmitter of a base station according to this embodiment. [Figure 20] Figure 20 is a photograph showing the appearance of a prototype of a single Shirei combiner. [Figure 21] 21(a) and 21(b) are Smith charts showing an example of the characteristics of the prototype of the single Shirei combiner of FIG. 20. In FIG. [Figure 22] FIG. 22 is a photograph showing the appearance of a prototype of a single power amplifier. [Figure 23] FIG. 23 is a graph showing input / output characteristics of the prototype example of the single power amplifier of FIG. [Figure 24] FIG. 24 is a photograph, substituted for a drawing, showing the appearance of a prototype example of a reactance compensation circuit switching type outphasing amplifier according to the embodiment. [Figure 25] FIG. 25 is a graph showing an example of efficiency characteristics in a prototype example of the reactance compensation circuit switching type outphasing amplifier of FIG. [Figure 26]Fig. 26(a) is a graph showing an example of modulated wave power efficiency obtained by measuring drain efficiency when a ZC sequence signal is amplified in the prototype example of the reactance compensation circuit switching type outphasing amplifier of Fig. 24. Fig. 26(b) is a graph showing an example of modulated wave power efficiency obtained by measuring drain efficiency when a signal to which CFR (Crest Factor Reduction: a peak reduction technique) is applied to a communication signal model is amplified in the prototype example of the reactance compensation circuit switching type outphasing amplifier of Fig. 24. [Figure 27] Fig. 27(a) is a circuit diagram showing another example of the configuration of the first amplifier in the transmitter of the base station device of Fig. 14. Fig. 27(b) is a circuit diagram showing another example of the configuration of the second amplifier in the transmitter of the base station device of Fig. 14. [Figure 28] FIG. 28 is an explanatory diagram showing an example of power supply to each of a plurality of terminal devices by beamforming from a base station according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that each drawing merely schematically illustrates shapes, sizes, positional relationships, corresponding relationships, configurations, processing, steps, procedures, etc., to the extent that the contents of the present disclosure can be understood, and therefore the present disclosure is not limited to only the shapes, sizes, positional relationships, corresponding relationships, configurations, processing, steps, and procedures exemplified in each drawing. Furthermore, the numerical values ​​exemplified in the present disclosure are merely preferred examples, and therefore the present disclosure is not limited to the exemplified numerical values.

[0021] A system according to an embodiment described herein is a system capable of wireless power transmission (WPT) from a mobile communication base station to a terminal device (e.g., a mobile station (UE) or an IoT device) to be supplied with power. The system according to the embodiment is a system that effectively utilizes unused wireless resources (resource blocks) that are not used for communication, among multiple wireless resources (resource blocks) set in a downlink radio 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.

[0022] In the system of this embodiment, a modulated signal with a lower PAPR (peak-to-average power ratio) than the communication signal is used as the signal for wireless power transmission (WPT), and the drain voltage when amplifying the signal for wireless power transmission (WPT) in a power amplifier (transmitting amplifier) ​​made of FET is controlled to be higher than that for the communication signal, thereby achieving higher output and efficiency of the power amplifier when amplifying the signal for wireless power transmission (WPT) at the base station.

[0023] In particular, in the system of this embodiment, in an integrated transmitter that performs wireless power transmission and wireless communication and is installed in a base station, the power amplifier circuit is configured as a single circuit module (device), thereby achieving high output and low power consumption. In one example of the power amplifier circuit of this embodiment, the susceptance value of the reactance compensation circuit in the Shelay combiner, which is part of the outphasing amplifier circuit, is adjusted using a variable inductor / capacitor to match the output timing of the wireless power transmission signal and the wireless communication signal, which are separated on the time axis.

[0024] As mentioned above, various communication methods have been discussed and researched in recent years in preparation for the next-generation mobile communication system standards (Beyond 5G / 6G). The applicant of this application is focusing on non-terrestrial networks (NTNs), including high-altitude platform stations (HAPSs), and wireless power transfer (WPTs). NTNs require radios to be mounted on aircraft, airships, drones, and other vehicles, which imposes significant limitations on the radios' weight and power consumption. HAPSs, in particular, operate in the stratosphere, where gravity is present at an altitude of approximately 20 km, making it particularly important to reduce the weight and power consumption of radios to maximize the aircraft's flight time. In particular, the power consumption of the power amplifier circuit (power amplifier) ​​and the weight of the heat dissipation device tend to account for a large portion of the radio's total weight, so power consumption must be minimized. Even in WPTs, because space-based wireless power transfer transmits a large amount of power to the power source, the power amplifier circuit (power amplifier) ​​on the transmitting side must have high output and high efficiency. In other words, increasing the efficiency of power amplifier circuits (power amplifiers) is an important issue in implementing both communications and WPT.

[0025] As mentioned above, the applicant of this application has proposed the integration of communications and WPT. As one of the technologies, the applicant has proposed a system in which a communication (information transmission) signal and a WPT signal are transmitted in a time-division manner on the downlink (DL) signal from a base station. By using a signal with a low PAPR (peak-to-average power ratio) for the WPT signal, it is possible to operate the transmitting power amplifier at a saturated output power level as close as possible. Generally, power amplifiers operate more efficiently as they approach their saturated output power level. However, in the Orthogonal Frequency Division Multiplexing (OFDM) method commonly used for 5G communications signals, the widening of the frequency bandwidth leads to an increase in PAPR. Furthermore, the adoption of high modulation levels such as 256QAM (256 Quadrature Amplitude Modulation) and 1024QAM tightens the tolerance for error vector magnitude (EVM). Under these conditions, the power amplifier must be operated in a high backoff region (first region) to ensure linearity.

[0026] In addition to the outphasing amplifier used in this embodiment, other power amplifier configurations that achieve high efficiency in the high backoff region (first region) have been proposed, including envelope tracking amplifiers, Doherty amplifiers, and more recently, load-modulated balanced amplifiers (LMBAs). However, Doherty amplifiers are currently the mainstream final-stage power amplifier for DL ​​signals in base stations. The applicant of the present application has proposed a configuration in which communication signals and WPT signals are amplified separately (see, for example, Patent Documents 1 to 4 mentioned above). In this configuration, for example, an asymmetric Doherty amplifier is used for the communication signal, and a high-efficiency standalone amplifier with waveform engineering that matches up to the third harmonic is used for the WPT signal. However, in this configuration, there is a concern that the overall device will become large because high-efficiency power amplifiers tailored to the characteristics of the communication signal and the WPT signal are used.

[0027] In this embodiment, a method is used in which the reactance compensation circuit in the Sherei combiner, which is part of the configuration of the outphasing amplifier circuit, is switched using an RF switch so that a single power amplifier circuit module can perform high-efficiency amplification according to the PAPR of each communication and WPT signal.

[0028] In the following embodiment, a terrestrial network system in which the antenna of the base station 10 is installed on the ground or sea will be described, but the present invention can also be applied to a non-terrestrial network (NTN) system in which the antenna of the base station 10 equipped with a transmitter having the power amplifier circuit of this embodiment is installed on an airborne platform such as the aforementioned HAPS or drone.

[0029] 1 is an explanatory diagram showing an example of a schematic configuration of a system according to this embodiment. The system according to this embodiment includes a cellular base station 10 that forms a communication area (cell) 10A, and a terminal device (hereinafter also referred to as "UE" (user equipment)) 20 that is a power supply target and can connect to the base station 10 and communicate wirelessly with the base station 10 when the terminal device is located in the communication area 10A.

[0030] The UE 20 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. The UE 20 may include, for example, an array antenna having multiple antenna elements. The UE 20 may also be an IoT device (also referred to as an "IoT device").

[0031] In FIG. 1 , a base station 10 includes multiple array antennas 110 each having a large number of antenna elements, and is capable of communicating with multiple UEs 20 using a massive MIMO (hereinafter also referred to as "mMIMO") transmission scheme. mMIMO is a wireless transmission technology that achieves high-capacity, high-speed communication by transmitting and receiving data using the array antennas 110. Furthermore, the base station 10 can communicate with multiple UEs 20 using a multi-user (MU)-MIMO transmission scheme, which performs beamforming to form beams 10B for each of the multiple UEs 20 in a time-division or simultaneous manner. By performing MU-MIMO transmission using a multi-element array antenna, an appropriate beam can be directed to each UE 20 according to the communication environment of each UE 20, thereby improving the communication quality of the entire cell. Furthermore, since communication with multiple UEs 20 can be performed using the same radio resources (time and frequency resources), the system capacity can be expanded.

[0032] 1, a part of the communication area 10A is a wireless power transmission area (hereinafter referred to as "WPT area") 10A' in which wireless power transmission is performed from the base station 10 to the terminal device 20. The WPT area 10A' may be an area smaller than the communication area 10A as shown in the figure, or may be an area of ​​the same or approximately the same size and location as the communication area 10A.

[0033] In the WPT area 10A', unused wireless resources (resource blocks) that are not used for communication are utilized as wireless power transmission blocks among resource blocks that are multiple wireless resources (time and frequency resources) that configure a downlink wireless frame from the base station 10. The base station 10 generates a transmission signal in which a signal for wireless power transmission (hereinafter also referred to as a "WPT signal") is assigned to the wireless power transmission block (WPT block), which is an unused wireless resource, in the downlink wireless frame to the UE 20, and transmits the transmission signal to the UE 20.

[0034] In particular, in fifth-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 on only some of the subcarriers in the radio frame. It is expected that the unused radio resources in the radio frame can be effectively utilized to transmit wireless power to UE 20.

[0035] The radio waves of the communication signals transmitted and received between the base station 10 and the UE 20 and the radio waves of the transmission signals to which the WPT signals are assigned and transmitted from the base station 10 to the UE 20 are, for example, millimeter waves or microwaves.

[0036] 2 is a block diagram showing an example of the main configuration of a base station 10 and a user equipment (UE) 20 constituting 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 one or more antennas 110. For example, a plurality of antennas 110 may be arranged corresponding to a plurality of sector cells.

[0037] The base station device 100 includes a communication signal processing unit 120 and a radio processing unit 130. The communication signal processing unit 120 processes signals such as various types of user data and control information transmitted and received between the UE 20 and the base station device 100.

[0038] Furthermore, during downlink communication with the UE 20, the communication signal processing unit 120 generates a downlink transmission signal including a WPT signal using unused radio resources among the multiple radio resources. For example, the WPT signal can be generated by modulating it using a modulation method with a lower PAPR (Peak to Average Power Ratio) (also referred to as "peak-to-peak ratio") than the communication signal. For example, the WPT signal may be a modulated signal modulated using a Zadoff-Chu sequence code, with a constant amplitude and a variable phase over time, or may be a signal modulated at one or more symbol points with a maximum or near-maximum amplitude among multiple symbol points of a digital modulation method. For example, the generation of the transmission signal may include primary modulation such as QAM (Quadrature Amplitude Modulation) for communication signals or modulation with a small PAPR for the WPT signal, as well as secondary modulation such as OFDM (Orthogonal Frequency Division Multiplexing) modulation.

[0039] The radio processing unit 130 transmits a transmission signal generated by the communication signal processing unit 120 from the antenna 110 to the UE 20, and outputs a received signal received from the UE 20 via the antenna 110 to the communication signal processing unit 120.

[0040] The process of including a WPT signal using unused radio resources in a transmission signal for downlink communication to the UE 20 may be performed based on subframes that constitute a radio frame for mobile communication.

[0041] In addition, the process of including a WPT signal using unused radio resources in the transmission signal for downlink communication to UE 20 may be performed autonomously by base station 10, or may be performed based on a request or instruction from UE 20 or a request or instruction from an external platform (e.g., a server, a cloud system).

[0042] In this embodiment, the radio processing unit 130 controls one or more beams formed by the array antenna 110 based on the BF control signal. The radio processing unit 130 also transmits a downlink transmission signal including a WPT signal generated by the communication signal processing unit 120 to the UE 20 via the antenna 110.

[0043] During downlink communication with the UE 20, the base station 10 may perform beamforming (BF) control to form an individual beam 10B for each UE 20 or for each UE group in a target area to which multiple UEs 20 belong, and may perform wireless power transmission for each UE 20 or for each UE group. The 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 unit 120, or may be performed by analog BF control in the radio processing unit 130.

[0044] 2, UE 20 includes antenna 210, radio processing unit 220, communication signal processing unit 230, power output unit 240, and battery 250. Antenna 210 is, for example, a small array antenna having a plurality of antenna elements. Radio processing unit 220 transmits transmission signals such as feedback information and user data generated by communication signal processing unit 230 from antenna 210 to base station 10, and outputs received signals received from base station 10 via antenna 210 to communication signal processing unit 230.

[0045] In this embodiment, the wireless processing unit 220 receives a transmission signal including a WPT dummy signal transmitted from the base station 10. The power output unit 240 has, for example, a rectifier, and outputs the power of the received signal, which is the transmission signal including the WPT dummy signal received from the base station 10, as received power for charging the battery. The battery 250 can be charged by the received power output from the power output unit 240.

[0046] 3(a) is an explanatory diagram showing an example of allocation of WPT blocks in radio resources (resource blocks) of a transmission signal including a WPT signal transmitted from a base station 10 according to this embodiment. Also, FIG. 3(b) is an explanatory diagram showing an example of a spectrum on the frequency axis in the secondary modulation of the OFDM system of the transmission signal transmitted from the base station 10 according to this embodiment. As shown in FIG. 3(a), the multiple radio resources used in downlink communication and uplink communication in the system of this embodiment are multiple resource blocks 30 defined by subcarriers on the frequency axis and slots on the time axis. 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. 3(b).

[0047] The resource blocks 30 constituting the radio resources in FIG. 3(a) are allocated to a plurality of consecutive subframes constituting a radio frame for mobile communication. In the illustrated example, each subframe is composed of a predetermined number (e.g., 20) of resource blocks, with communication subframes (hereinafter referred to as "communication frames") F1 and WPT subframes (hereinafter referred to as "WPT frames") F2 alternately positioned. The communication frame F1 includes resource blocks 31 for uplink and downlink communications, and the WPT frame F2 includes resource blocks 32 for WPT, which are cross-hatched in the figure. Of the resource blocks 31 in the communication frame F1, the plurality of uplink resource blocks are allocated to signals for uplink communication of user data and signals for communication of feedback information for WPT from the UE 20, and the plurality of downlink resource blocks are allocated to signals for downlink communication of user data and information. Furthermore, the resource block 32 in the WPT frame F2 is allocated to a downlink WPT signal.

[0048] As shown in FIG. 3(a), the transmission signal transmitted from the base station 10 according to this embodiment includes a communication signal as a first signal to be amplified and a WPT signal as a second signal to be amplified, which are separated on the time axis.

[0049] FIG. 4 is a graph showing an example of the characteristics of output power Pout [dBm] and efficiency PAE [%] versus input power Pin [dBm] of a power amplifier in a base station 10 according to this embodiment. Curve A in the graph shows the results of a simulation of AC output power Pout [dBm] versus AC input power Pin [dBm] of the power amplifier, and the plotted points marked with "□" represent the measurement results of the output power Pout [dBm]. Curve B in the graph shows the results of a simulation of power added efficiency (PAE) [%], which is one index value of efficiency versus input power Pin [dBm] of the power amplifier, and the plotted points marked with "◯" represent the measurement results of the efficiency PAE [%]. Here, the PAE [%] of a power amplifier is defined as (Pout-Pin) / Pdc, where Pdc is the DC power input (applied) to the power amplifier. The linear region (first region) in the graph is the region where the relationship between input power Pin and output power Pout is linear or nearly linear. The saturation region (second region) in the figure is the region where the output power Pout is saturated or nearly saturated with increasing input power Pin. The peak of the power amplifier efficiency PAE is located near the boundary between the linear region and the saturation region.

[0050] In base station 10, when a communication signal consisting of a modulated signal with a high PAPR (Peak to Average Power Ratio) is amplified by a power amplifier, the linear region (first region) of the power amplifier, which has low output power and low efficiency, is used. For example, the operating parameters (e.g., drain voltage) of the power amplifier are set so that the average power of the communication signal (modulated signal) is located at a point (center of the linear region) corresponding to a backoff on the low power side from the start point (left end) of the saturation region in Figure 4.

[0051] On the other hand, in wireless power transmission (WPT), it is desirable to amplify the WPT signal in a region of high output power and high efficiency (second region).

[0052] Therefore, in this embodiment, an OFDM modulated signal having a lower PAPR (peak-to-average power ratio) than the communication signal is used as the WPT signal so that the WPT signal can be amplified in the high output power and high efficiency range of the power amplifier of the wireless processing unit 130.

[0053] Fig. 5(a) is an explanatory diagram showing an example of the arrangement of symbol points 41 in the primary modulation of the QAM method of a communication signal transmitted from the base station 10 according to this embodiment. Fig. 5(a) is a constellation diagram showing the arrangement of multiple symbol points (64-value symbol points) in the case of the 64QAM method. Fig. 5(b) is an explanatory diagram showing an example of the arrangement of symbol points in the modulation of a WPT signal transmitted from the base station 10 according to this embodiment. In Figs. 5(a) and 5(b), the horizontal axis indicates the in-phase channel component, and the vertical axis indicates the quadrature channel component.

[0054] In this embodiment, an OFDM modulated signal having a lower PAPR (Peak to Average Power Ratio) than the communication signal is used as the WPT signal. For example, in Fig. 5(a), a WPT signal consisting of an OFDM modulated signal modulated only by the outermost or a plurality of symbol points 41S around the outermost periphery, which have the largest amplitude, among a plurality of symbol points 41 of the QAM method for the communication signal, may be used.

[0055] Also, as shown in the constellation diagram of Fig. 5(b), a WPT signal may be used that is made up of an OFDM modulated signal modulated at symbol point 42, where the phase changes with constant amplitude over time. The OFDM modulated signal at symbol point 42 in Fig. 5(b) can be generated using, for example, a Zadoff-Chu sequence code.

[0056] As described above, in this embodiment, the power amplifier circuit of the transmitter is configured using an outphasing amplifier so that a single power amplifier circuit module can perform high-efficiency amplification according to the PAPR of each of the communication signal and the WPT signal, and the reactance compensation circuit in the Sherei combiner, which is part of the circuit configuration of the outphasing amplifier, is switched using an RF switch.

[0057] 6 is a block diagram showing an example of a configuration of a main part of a transmitter 101 of a base station device 100 according to an embodiment. In FIG. 6, the transmitter 101 of the base station device 100 includes a communication signal processing unit 120 and a radio processing unit 130 having a power amplifier circuit. The communication signal processing unit 120 includes a transmission signal detection unit 121 and a transmission signal processing unit 122. The transmission signal detection unit 121 detects a communication signal and a WPT signal, and outputs a trigger signal corresponding to the signal switching timing between the communication signal and the WPT signal. The transmission signal processing unit 122 generates a first signal (+θ(t)) having a first phase (+θ) and a second signal (−θ(t)) having a second phase (−θ) different from the first phase from the transmission signal to be amplified, and outputs them to the radio processing unit 130.

[0058] The radio processing unit 130 includes a power amplifier circuit having an outphasing amplifier 131. The outphasing amplifier 131 receives the first signal (+θ(t)) and the second signal (−θ(t)) output from the transmission signal detection unit 121, and includes a Shear combiner including a reactance compensation circuit, which will be described later.

[0059] 7 is a block diagram showing an example of a configuration of a main part of a transmission signal processing unit 122 that generates an input signal (+θ(t), −θ(t)) to an outphasing amplifier 131 in a communication signal processing unit 120 provided in a transmitter 101 of a base station device 100 according to this embodiment. In FIG. 7, the communication signal processing unit 120 includes a first frequency modulated wave generating unit 1220(1) and a second frequency modulated wave generating unit 1220(2).

[0060] The first frequency-modulated wave generation unit 1220(1) includes a first in-phase component signal generation unit 1221(1), a first quadrature component signal generation unit 1222(1), and a first IQ modulation unit 1223(1). The first in-phase component signal generation unit 1221(1) generates an in-phase component signal I1(t) corresponding to a first signal from a signal to be transmitted, and the first quadrature component signal generation unit 1222(1) generates a quadrature component signal Q1(t) corresponding to the first signal from the signal to be transmitted. The first IQ modulation unit 1223(1) performs IQ modulation based on the in-phase component signal I1(t) output from the first in-phase component signal generation unit 1221(1) and the quadrature component signal Q1(t) output from the first quadrature component signal generation unit 1222(1), thereby generating a first frequency-modulated signal (a signal without amplitude modulation) s FM1 (t) and outputs it as the first signal (+θ(t)).

[0061] The second frequency-modulated wave generation unit 1220(2) includes a second in-phase component signal generation unit 1221(2), a second quadrature component signal generation unit 1222(2), and a second IQ modulation unit 1223(2). The second in-phase component signal generation unit 1221(2) generates an in-phase component signal I2(t) corresponding to the second signal from a signal to be transmitted, and the second quadrature component signal generation unit 1222(2) generates a quadrature component signal Q2(t) corresponding to the second signal from the signal to be transmitted. The second IQ modulation unit 1223(2) performs IQ modulation based on the in-phase component signal I2(t) output from the second in-phase component signal generation unit 1221(2) and the quadrature component signal Q2(t) output from the second quadrature component signal generation unit 1222(2), thereby generating a second frequency-modulated signal (a signal without amplitude modulation) s FM2 (t) and outputs it as the second signal (-θ(t)).

[0062] FIG. 8 is a circuit diagram showing an example of a general circuit configuration of an outphasing amplifier 131′. In FIG. 8, the outphasing amplifier 131′ includes a first amplifier 132(1), a second amplifier 132(2), and a Shelay combiner 133. The Shelay combiner 133 includes a reactance compensation circuit (+jB C,-jB C ) 1331 and impedance converters 1332(1) and 1332(2). A first signal (+θ(t)) and a second signal (−θ(t)) having a phase difference of a predetermined outphasing angle ±θ(t) are input to the outphasing amplifier 131′. At this time, the susceptance value of the reactance compensation circuit 1331 in the Shear combiner 133, which is connected after the outputs of the individual power amplifiers 132(1) and 132(2), is set to B C Then, the ideal efficiency η of the outphasing amplifier 131' OPA is expressed by the following equation (1).

number

[0063] η in the above equation (1) B is the normalized efficiency, which is set to 1 here. Also, G0 and B0 in the above equation (1) are respectively expressed by the following equations (2) and (3). In this case, the output back-off OBD (dB) is expressed by the following equation (4).

number

number

number

[0064] From the above equation (1), the most efficient condition is B0=B C The instantaneous value of B0 is determined by θ(t) from the above equation (2), so after setting the output back-off value for the best efficiency point, the value of θ(t) is calculated from the above equation (4), and B0 is then calculated. C Determine.

[0065] Figure 9 shows the results for multiple susceptance values ​​B C (B C =0.01,B C =0.01286,B C= 0.02). In the ideal characteristics, the susceptance value B C By adjusting the susceptance value B, it is possible to adjust the target output back-off value for the best efficiency point. C Figures 3(a) and 3(b) show graphs comparing the efficiency characteristics when optimized with target output back-off values ​​of 6 dB and 12 dB with the ideal characteristics of the Doherty amplifier. The line marked C201 in the figures shows the efficiency characteristics of the outphasing amplifier, and the line marked C202 in the figures shows the efficiency characteristics of the Doherty amplifier. The efficiency of the Doherty amplifier was calculated using the following equations (5) and (6).

number

number

[0066] Here, the target back-off value is 6 dB (targetOBO=-6 dB) when α=0.5, and 12 dB (targetOBO=-12 dB) when α=0.25. Compared to the Doherty amplifier, the Doherty amplifier is more efficient up to the target back-off value, but the outphasing amplifier is more efficient from the target back-off value to the saturated output level.

[0067] The difference in efficiency characteristics for the above CW (continuous wave) signal is affected by the difference in PAPR of the modulated wave, as shown below. Reference (Y. Takagi, T. Hirakawa, M. Konishi and Y. Ohta, "Power In accordance with the calculation method in "5G NR Downlink Consumption and Reduction," in IEEE Access, vol. 12, pp. 55051-55061, 2024," a PAPR of 4.3 dB ZC (Zadoff-Chu) sequence signal (see references (Stefania Sesia; Issam Toufik; Matthew Baker, "Synchronization and Cell Search," in LTE - The UMTS Long Term Evolution: From Theory to Practice, Wiley, 2011, pp. 151-164)) was applied to the communication signal test model TM3.1a (256QAM modulation, full buffer) with target backoff values ​​of 6 dB and 8.75 dB, and the CFR (crest factor Figures 11(a) and 11(b) show the efficiency characteristics when a signal with a 12 dB back-off reduction is input to an outphasing amplifier and a Doherty amplifier with a target back-off value of 12 dB. Similar to the characteristics for a CW signal, the Doherty amplifier is more efficient in the low output range, while the outphasing amplifier is more efficient in the high output range.

[0068] In the power amplifier circuit of the transmitter of this embodiment, in order to aim for high output and high efficiency in both communication and WPT, the outphasing amplifier has an efficiency advantage when considering only the ideal characteristics of efficiency. Therefore, the susceptance value B in the reactance compensation circuit of the Sherei combiner that determines the target back-off value in the outphasing amplifier is set to C are configured to be switched by an RF switch.

[0069] Fig. 12 is a circuit diagram showing an example of the circuit configuration of an outphasing amplifier 131 used in the transmitter 101 of the base station 10 according to this embodiment. The outphasing amplifier 131 in Fig. 12 is a reactance compensation circuit adjustment type outphasing amplifier. In Fig. 12, parts that are common to those in Fig. 8 above are assigned the same reference numerals, and descriptions thereof will be omitted.

[0070] 12, the reactance compensation circuit 1331 in the Shear combiner 133 has a variable capacitor C as a variable capacitive reactance element and a variable inductor L as a variable inductive reactance element. The variable capacitor C and the variable inductor L are connected in series, with the variable capacitor C connected to the output path of the first amplifier 132(1) and the variable inductor L connected to the output path of the second amplifier 132(2). The intermediate connection point of the variable capacitor C and the variable inductor L is grounded.

[0071] In the outphasing amplifier 131 of FIG. 12, the susceptance value B of the reactance compensation circuit 1331 in the Shear combiner 133 is adjusted in accordance with the desired input / output power ratio (PAPR) of the signal to be amplified in accordance with the signal timing of the communication signal and the WPT signal. C For example, when a communication signal consisting of a modulated signal with a high input / output power ratio (PAPR) is amplified in a linear region (first region) where the output back-off of the outphasing amplifier 131 is large, the susceptance value B of the reactance compensation circuit 1331 is adjusted so that the efficiency peaks in that region. C On the other hand, when a WPT signal consisting of a modulated signal with a low input / output power ratio (PAPR) is amplified in a saturation region (second region) where the output back-off of the outphasing amplifier 131 is small, the susceptance value B of the reactance compensation circuit 1331 is adjusted so that the efficiency peaks in that region. C The variable capacitor C and the variable inductor L are adjusted to increase the

[0072] Figures 13(a) and 13(b) are circuit diagrams showing other examples of the circuit configuration of the outphasing amplifier 131 used in the transmitter 101 of the base station 10 according to this embodiment. The outphasing amplifier 131 in Figures 13(a) and 13(b) is a reactance compensation circuit switching type outphasing amplifier. In Figures 13(a) and 13(b), parts that are common to those in Figures 8 and 12 above are assigned the same reference numerals, and descriptions thereof will be omitted.

[0073] 13(a) and 13(b), the reactance compensation circuit 1334 in the Shear combiner 133 includes a first reactance compensation circuit 1335 and a second reactance compensation circuit 1336 having different susceptance values, and a pair of a first switch 1337(1) and a second switch 1337(2). In the illustrated example, the susceptance value B C1 is the susceptance value B of the second reactance compensation circuit 1336 C2 Furthermore, the first switch 1337(1) and the second switch 1337(2) are each, for example, an RF switch capable of switching a high-frequency radio frequency signal path.

[0074] In FIG. 13(a), the first reactance compensation circuit 1335 and the second reactance compensation circuit 1336 each have a fixed or semi-fixed capacitive susceptance value B C1 and a fixed or semi-fixed inductive susceptance value B. C213(a), the first reactance compensation circuit 1335 includes a fixed or semi-fixed first capacitor C1 as a capacitive reactance element and a fixed or semi-fixed first inductor L1 as an inductive reactance element. The intermediate connection point between the first capacitor C1 and the first inductor L1 is grounded. The second reactance compensation circuit 1336 includes a second capacitor C2 and a second inductor L2. The intermediate connection point between the second capacitor C2 and the second inductor L2 is grounded. The first capacitor C1 and the second capacitor C2 are selectively connectable to the output path of the first amplifier 132(1) via a first switch 1337(1). The first inductor L1 and the second inductor L2 are selectively connectable to the output path of the second amplifier 132(2) via a second switch 1337(2).

[0075] On the other hand, in FIG. 13(b), the first reactance compensation circuit 1335 and the second reactance compensation circuit 1336 each have a variable capacitive susceptance value B C1 and a variable inductive susceptance value B. C2 13, the first reactance compensation circuit 1335 has a first variable capacitor C1 as a capacitive reactance element and a first variable inductor L1 as an inductive reactance element. The intermediate connection point between the first variable capacitor C1 and the first variable inductor L1 is grounded. The second reactance compensation circuit 1336 has a second variable capacitor C2 and a second variable inductor L2. The intermediate connection point between the second variable capacitor C2 and the second variable inductor L2 is grounded. The first variable capacitor C1 and the second variable capacitor C2 are selectively connectable to the output path of the first amplifier 132(1) via a first switch 1337(1). The first variable inductor L1 and the second variable inductor L2 are selectively connectable to the output path of the second amplifier 132(2) via a second switch 1337(2).

[0076] In each of the outphasing amplifiers 131 in FIGS. 13(a) and 13(b), the susceptance value B of the reactance compensation circuit 1331 in the Shear combiner 133 is adjusted in accordance with the desired input / output power ratio (PAPR) of the signal to be amplified in accordance with the signal timing of the communication signal and the WPT signal. C For example, when a communication signal consisting of a modulated signal with a high input / output power ratio (PAPR) is amplified in a linear region (first region) where the output back-off of the outphasing amplifier 131 is large, the susceptance value B C On the other hand, when a WPT signal consisting of a modulated signal with a low input / output power ratio (PAPR) is amplified in a saturation region (second region) where the output back-off of the outphasing amplifier 131 is small, the susceptance value B of the reactance compensation circuit 1331 is changed to C To increase the susceptance value B C is switched to the second reactance compensation circuit 1336 having a larger

[0077] In the outphasing amplifier 131 of FIG. 13(b), the first reactance compensation circuit 1335 and the second reactance compensation circuit 1336 are switched in accordance with the signal timing of the communication signal and the WPT signal, and the susceptance value B of the reactance compensation circuit 1331 in the Shear combiner 133 is adjusted in accordance with the desired input / output power characteristic (PAPR) of the signal to be amplified. C may be fine-tuned with variable capacitors C1 and C2 and variable inductors L1 and L2.

[0078] Fig. 14 is a block diagram showing an example of the configuration of the main parts of a base station device 100 including a transmitter 101 having a reactance compensation circuit-switching outphasing amplifier 131 according to the embodiment. In Fig. 14, parts common to those in Figs. 6, 8, 12, and 13 described above are given the same reference numerals, and descriptions thereof will be omitted. The outphasing amplifier 131 in Fig. 14 has a first reactance compensation circuit 1335 and a second reactance compensation circuit 1336 each configured with variable capacitors C1 and C2 and variable inductors L1 and L2 similar to those in Fig. 13(b) described above.

[0079] 14, the first amplifier 132(1) includes an input-side bias & matching circuit 1321(1), a power amplifier 1322(1) configured with a FET or the like, and an output-side bias & matching circuit 1323(1). Similarly, the second amplifier 132(2) includes an input-side bias & matching circuit 1321(2), a power amplifier 1322(2) configured with a FET or the like, and an output-side bias & matching circuit 1323(2). The input-side bias & matching circuits 1321(1) and 1321(2) and the output-side bias & matching circuits 1323(1) and 1323(2) can adjust or switch the bias and matching circuit in accordance with the signal timing of the communication signal and the WPT signal, based on a trigger signal output from the transmission signal detection unit 121.

[0080] Fig. 15 is a flowchart showing an example of a control flow in a base station device 100 including a transmitter 101 having the reactance compensation circuit switching type outphasing amplifier 131 of Fig. 14. In Fig. 15, when a radio signal to be transmitted (transmission signal) is output from the transmitter 101 (S101), the control unit of the base station device 100 determines whether the radio signal to be transmitted (transmission signal) is a communication signal (1) or a WPT signal (0) (S102).

[0081] When the radio signal to be transmitted (transmission signal) is a communication signal (1), the control unit of the base station device 100 switches the reactance compensation circuit 1334 of the outphasing amplifier 131, the input-side bias and matching circuits 1321(1) and 1321(2) of the first amplifier 132(1) and the second amplifier 132(2), and the output-side bias and matching circuits 1323(1) and 1323(2) to a system for a PAPR target of 8 to 12 dB (S103).

[0082] Furthermore, the control unit of the base station device 100 adjusts the susceptance value B n The variable inductor L1 and the variable capacitor C1 are adjusted so that the value falls within the range of 0 to 0.0197 (S104).

[0083] On the other hand, when the wireless signal to be transmitted (transmission signal) is a WPT signal (0), the control unit of the base station device 100 switches the reactance compensation circuit 1334 of the outphasing amplifier 131, the input-side bias and matching circuits 1321(1), 1321(2) of the first amplifier 132(1) and the second amplifier 132(2), and the output-side bias and matching circuits 1323(1), 1323(2) to a system for a PAPR target of 0 to 4 dB (S105).

[0084] Furthermore, the control unit of the base station device 100 adjusts the susceptance value B n The variable inductor L2 and the variable capacitor C2 are adjusted so that the value falls within the range of 0.0197 to 0.002 (S106).

[0085] Fig. 16 is an explanatory diagram showing an example of a control system in a base station device 100 including a transmitter 101 having a reactance compensation circuit switching type outphasing amplifier 131 of Fig. 14. In Fig. 16, a control unit 140 of the base station device 100 outputs a trigger signal 141 at each timing of signal switching from the communication signal to the WPT signal and at each timing of signal switching from the WPT signal to the communication signal, based on the detection result of the wireless signal (transmission signal) to be transmitted by the transmission signal detection unit 121.

[0086] The trigger signal 141 is sent to various switches and is used for switching operations by the various switches. For example, the trigger signal 141 is sent to each of switches 1338 and 1339 that switch the control DC voltages applied to the first switch 1337(1) and the second switch 1337(2) provided in the reactance compensation circuit 1334 of the Shear combiner 133, and is used for switching the susceptance value of the reactance compensation circuit 134. Furthermore, for example, the trigger signal 141 is sent to the input-side matching circuit selector switch 1324(1), input-side bias selector switch 1325(1), output-side matching circuit selector switch 1326(1), and output-side bias selector switch 1327(1) of the first amplifier 132(1), and is used for switching the matching circuit and bias on the input side and the matching circuit and bias on the output side of the first amplifier 132(1). Furthermore, for example, the trigger signal 141 is sent to the input-side matching circuit changeover switch 1324(2), the input-side bias changeover switch 1325(2), the output-side matching circuit changeover switch 1326(2), and the output-side bias changeover switch 1327(2) of the second amplifier 132(2), and is used to switch the matching circuit and bias on the input side and the matching circuit and bias on the output side of the second amplifier 132(2).

[0087] The trigger signal 141 is also sent to a PAPR detector 142 that detects the input / output power characteristic (PAPR) of the signal to be amplified. Based on this trigger signal 141, the PAPR detector 142 detects the input / output power characteristic (PAPR) of the signal to be amplified, and the susceptance value B of the reactance compensation circuit 1334 of the Shear combiner 133 is set to n (or the aforementioned B C ) is set to a value within a predetermined range.

[0088] 17(a) and 17(b) are circuit diagrams showing examples of the configuration of a variable capacitor C. In FIG. 17(a), the circuit of the variable capacitor C is configured to use capacitors C1 and C2 as fixed or semi-fixed capacitive reactance elements having different capacitances, which are switched by a switch. In FIG. 17(b), the circuit of the variable capacitor C is configured to use fixed or semi-fixed capacitive reactance elements XC1 and XC2 having different capacitive reactances, which are switched by a switch. The variable capacitor C may be a varactor diode, which is a variable capacitive reactance element.

[0089] 18(a) and 18(b) are circuit diagrams showing examples of the configuration of a variable inductor L. In Fig. 18(a), the circuit of the variable inductor L is configured to use inductors L1 and L2 as fixed or semi-fixed inductive reactance elements having different inductances, which are switched by a switch. Also, in Fig. 18(b), the circuit of the variable inductor L is configured to use inductors XL1 and XL2 as fixed or semi-fixed inductive reactance elements having different inductances, which are switched by a switch.

[0090] 19 is a circuit diagram showing an example of a more specific circuit configuration (equivalent circuit) of the Shelay combiner 133 in the reactance compensation circuit switching outphasing amplifier 131 used in the transmitter 101 of the base station 10 according to this embodiment. Fig. 19 is a circuit example showing in detail the components from the bias and matching circuits 1323(1) and 1323(2) (output circuit stages) on the output sides of the first amplifier 132(1) and the second amplifier 132(2) to the signal output Pout to the load via the impedance converters 1332(1) and 1332(2). Analog Devices' HMC545A RF switches are used for the first switch 1337(1) and the second switch 1337(2). By controlling the ON / OFF of the control DC voltage (8V) applied to this RF switch from an external power supply using switches (SW) 1338 and 1339, which serve as the reactance compensation circuit selector switches described above, the RF signal path can be switched between the path of C1 and L1 or the path of C2 and L2. For example, in the prototype circuit of Figure 19, switch 1338 is open and switch 1339 is shorted, so that the control DC voltage (8V) is applied to the A terminals of RF switches 1337(1) and 1337(2) and the B terminals are grounded, and the RF signal path becomes the path from terminal C0 to terminal C1. As a result, the path of the RF signal input to RF switches 1337(1) and 1337(2) becomes the path of C1 and L1. On the other hand, when switch 1338 is shorted and switch 1339 is opened, a control DC voltage (8 V) is applied to the B terminals of RF switches 1337(1) and 1337(2), the A terminals are grounded, and the RF signal path becomes a path from terminal C0 to terminal C2. As a result, the RF signal path input to RF switches 1337(1) and 1337(2) becomes a path from C2 to L2. In the prototype example of FIG. 19, a manually operable physical switch is connected to the external DC power supply so that the RF signal path can be easily switched manually. In the Shear combiner 133 of this embodiment, for example, instead of manually operable physical switches, switches that can switch the control DC voltage (8 V) to RF switches 1337(1) and 1337(2) on and off in response to the above-mentioned trigger signal are used as switches (SW) 1338 and 1339.

[0091] In addition to the reactance compensation capacitors and inductors, DC blocking capacitors (Ca, Cb, 82 pF) must also be connected to the RF signal connections of the RF switch. Therefore, the circuit design in this example was carried out taking into account the capacitance values ​​of these DC blocking capacitors.

[0092] FIG. 20 is a photograph of the exterior of a prototype of a single She-Ray combiner 1330 applicable to the reactance compensation circuit switching type outphasing amplifier 131, which is implemented with capacitors C1 and C2 and inductors L1 and L2 shown in FIG. 19. FIGS. 21(a) and 21(b) are Smith charts showing examples of admittance characteristics in the prototype of the single She-Ray combiner 1330 shown in FIG. 20. FIG. 21(a) shows the characteristics in the C1&L1 mode in which the capacitor C1 and inductor L1 are switched to, and FIG. 21(b) shows the characteristics in the C2&L2 mode in which the capacitor C2 and inductor L2 are switched to. The "★" in the figure is the target value, the "●" in the figure is a value obtained by computer simulation of the circuit, and the "x" in the figure is an actually measured value. The fundamental frequency is 915 MHz, and the characteristic impedance Z0 and load resistance R of the impedance converters 1332(1) and 1332(2) are 1 / 2. L was set to 50 Ω. The target values ​​in Figures 21(a) and 21(b) represent the admittance values ​​obtained by determining the target backoff value, then calculating the values ​​of C1, L1, and C2, L2 in Figure 19, and connecting these values ​​in parallel with a 100 Ω ideal resistor. The simulated values ​​include all of the values ​​from the electromagnetic field analysis of the PCB pattern, the S-parameters of the RF switch, and the DC blocking capacitor. The measured values ​​are those obtained by removing the line length between the connector and the DC blocking capacitor. For all components except L1, the circuit design and actual measurements were roughly consistent. Although there was a slight discrepancy between the target value for L1 and the simulated and measured values, the input / output characteristics of the outphasing amplifier 131 were good, so this inductance value was used for the prototype implementation.

[0093] FIG. 22 is a photograph showing the appearance of a prototype of a standalone power amplifier 1310' applicable to the first amplifier 132(1) and the second amplifier 132(2) connected to the Sherei combiner 133 of the outphasing amplifier 131 of this embodiment. A low-loss resin substrate (Megtron6 ​​R-5775 manufactured by Panasonic, εr = 3.71, tanδ = 0.003, substrate thickness: 0.5 mm) was selected for the circuit board. A GaN HEMT (CG2H40010F) manufactured by MACOM (formerly Wolfspeed, Cree) was used for the amplifying element. A circuit matching up to the third harmonic was implemented for output matching. The bias conditions were a drain bias of 28 V and a gate bias of -2.8 V (class AB).

[0094] Fig. 23 is a graph showing the input / output characteristics of a prototype example of the single power amplifier 1310' of Fig. 22. Under a 50 Ω load condition, high efficiency results were obtained with a maximum drain efficiency of 87.0% and a maximum power added efficiency (PAE) of 83.6% at a saturated output power of 40.1 dBm.

[0095] From the results of the above prototype example, good results were obtained from actual measurements of the Sherei combiner 1330 and the single power amplifier 1310', so these were combined and implemented to produce a prototype of the outphasing amplifier 131.

[0096] FIG. 24 is a photograph showing the appearance of a prototype of a reactance compensation circuit-switching outphasing amplifier 131 according to an embodiment. The drain bias and gate bias of the individual power amplifiers in the first amplifier 132(1) and the second amplifier 132(2) are common between the upper and lower sides. Multiple capacitors are implemented in the gate bias circuit to prevent oscillation. In the prototype of FIG. 24, similar to the circuit of FIG. 19, the RF signal path can be switched between the path of C1 and L1 or the path of C2 and L2 by controlling the ON / OFF of the control DC voltage (8 V) applied to RF switches 1337(1) and 1337(2) using switches (SW) 1338 and 1339.

[0097] Figure 25 is a graph showing an example of the efficiency characteristics of a prototype of the reactance compensation circuit-switched outphasing amplifier 131 shown in Figure 24. Measurements were performed using the inter-channel phase control function of a Keysight Technologies signal generator N5186A. The input power to the upper and lower inputs of the outphasing amplifier 131 was set to 25 dBm, and the phase was measured at ±180° in 1° increments. As shown in Figure 25, the measurement results for the CW signal of the prototype outphasing amplifier 131 showed that when the paths through the RF switches 1337(1) and 1337(2) were C1 and L1 (hereinafter referred to as "RF switch pattern 1"), the drain efficiency was 71.1% at a saturated output power of 45.0 dBm, 50.8% at an 8.7 dB output backoff (Pout = 36.3 dBm), and 70.1% at a 2.9 dB output backoff (Pout = 42.1 dBm). When the paths through the RF switches 1337(1) and 1337(2) are C2 and L2 (hereinafter referred to as "RF switch pattern 2"), the drain efficiency was 71.6% at a saturated output power of 45.1 dBm, 43.0% at an 8.8 dB output backoff (Pout = 36.3 dBm), and 72.8% at a 3.0 dB output backoff (Pout = 42.1 dBm). By switching the RF switches 1337(1) and 1337(2), the efficiency was improved by 7.8% at Pout = 36.3 dBm and 2.7% at Pout = 42.1 dBm. As per the principle of the outphasing amplifier, the susceptance value B of the reactance compensation circuit C It was confirmed through actual measurements that the output back-off value at the point of maximum efficiency can be adjusted by adjusting the above.

[0098] Next, we estimated the efficiency for modulated waves using the measurement results for the CW signal. When calculations were performed using the same modulated waves as those for the ZC sequence signal and the signal with CFR applied to the communication signal test model TM3.1a described above, the efficiency characteristics for a ZC sequence signal with a PAPR of 4.3 dB were as shown in Figure 26(a), while the efficiency characteristics for a signal with CFR applied to the communication signal test model TM3.1a with a PAPR of 8.75 dB were as shown in Figure 26(b). Here, if we define 0 dB of normalized output power as a modulated wave output power of 45.0 dBm, for the ZC sequence signal, at a modulated wave output power of 41.0 dBm, the efficiency was 67.7% for RF switch pattern 1 and 68.7% for RF switch pattern 2, a 1.0% improvement. The results showed that RF switch pattern 2 provided better efficiency at modulated wave output powers of 40.2 dBm or higher. For a signal with a PAPR of 8.75 dB, when the modulated wave output power was 36.2 dBm, the efficiency improved by 5.6%, to 47.6% for RF switch pattern 1 and 42.0% for RF switch pattern 2. From the above, it was demonstrated that by switching the reactance compensation circuit in the outphasing amplifier 131 of this embodiment, highly efficient amplification is possible in accordance with the modulated wave to be amplified.

[0099] 14, the wireless processing unit 131 may switch the bias voltage and the input-side and output-side matching circuits in accordance with the signal timing of the communication signal and the WPT signal, based on a trigger signal output from the communication signal processing unit 120. For example, the wireless processing unit 131 may switch the input-side and output-side bias voltages and the input-side and output-side matching circuits based on the trigger signal output from the communication signal processing unit 120, so as to use the bias voltages for input-side communication and output-side communication and the matching circuits for input-side communication and output-side communication when amplifying the communication signal, and to use the bias voltages for input-side wireless power transmission and output-side wireless power transmission and the matching circuits for input-side wireless power transmission and output-side wireless power transmission when amplifying the WPT signal.

[0100] 27(a) is a circuit diagram showing another example of the configuration of the first amplifier 132(1) in the transmitter 101 of the base station device 100 of FIG. 14 described above. In FIG. 27(a), the first amplifier 132(1) includes, on the upstream side of the power amplifier 1322(1), a first bias & matching circuit 1321(1) for input-side communication corresponding to the communication signal, a first bias & matching circuit 1321′(1) for input-side WPT corresponding to the WPT signal, and a set of PA input matching circuit changeover switches 1324(1) (see FIG. 16). The PA input matching circuit changeover switch 1324(1) also serves as the PA input-side bias voltage changeover switch 1325(1) (see FIG. 16). The PA input matching circuit changeover switch 1324(1) changes the first bias voltage V for input-side communication when amplifying the communication signal based on a trigger signal output from the communication signal processing unit 120. G1A and using matching circuit A for input side communication, the first bias voltage V for input side WPT when amplifying the WPT signal. G1B and switching between the first bias & matching circuit 1321(1) for input side communication and the first bias & matching circuit 1321′(1) for input side WPT so as to use the matching circuit B for input side WPT.

[0101] 27(a), the first amplifier 132(1) includes, at the rear stage of the power amplifier 1322(1), a first bias & matching circuit 1323(1) for output-side communication corresponding to the communication signal, a first bias & matching circuit 1323'(1) for output-side WPT corresponding to the WPT signal, and a set of PA output matching circuit changeover switches 1326(1) (see FIG. 16). The PA output matching circuit changeover switch 1326(1) also serves as the PA output-side bias voltage changeover switch 1325(1) (see FIG. 16). The PA output matching circuit changeover switch 1326(1) changes the first bias voltage V for output-side communication when amplifying the communication signal based on a trigger signal output from the communication signal processing unit 120. D1A and using the matching circuit A for output side communication, the first bias voltage V for output side WPT when amplifying the WPT signal. D1Band switching between the first bias & matching circuit 1323(1) for output side communication and the first bias & matching circuit 1323′(1) for output side WPT so as to use the matching circuit B for output side WPT.

[0102] 27(b) is a circuit diagram showing another example of the configuration of the second amplifier 132(2) in the transmitter 101 of the base station device 100 of FIG. 14 described above. In FIG. 27(b), the second amplifier 132(2) includes, on the upstream side of the power amplifier 1322(2), a second bias & matching circuit 1321(2) for input-side communication corresponding to the communication signal, a second bias & matching circuit 1321′(2) for input-side WPT corresponding to the WPT signal, and a set of PA input matching circuit changeover switches 1324(2) (see FIG. 16). The PA input matching circuit changeover switch 1324(2) also serves as the PA input-side bias voltage changeover switch 1325(2) (see FIG. 16). The PA input matching circuit changeover switch 1324(2) changes the second bias voltage V for input-side communication when amplifying the communication signal based on a trigger signal output from the communication signal processing unit 120. G2A and using matching circuit A for input side communication, when amplifying the WPT signal, the second bias voltage V for the input side WPT G2B and the second bias & matching circuit 1321(2) for input side communication and the second bias & matching circuit 1321′(2) for input side WPT are switched so as to use the matching circuit B for input side WPT.

[0103] 27(b), the second amplifier 132(2) includes, at the rear stage of the power amplifier 1322(2), a second bias & matching circuit 1323(2) for output-side communication corresponding to the communication signal, a second bias & matching circuit 1323'(2) for output-side WPT corresponding to the WPT signal, and a set of PA output matching circuit changeover switches 1326(2) (see FIG. 16). The PA output matching circuit changeover switch 1326(2) also serves as the PA output-side bias voltage changeover switch 1325(2) (see FIG. 16). The PA output matching circuit changeover switch 1326(2) changes the second bias voltage V for output-side communication when amplifying the communication signal based on a trigger signal output from the communication signal processing unit 120. D2Aand using the matching circuit A for output side communication, when amplifying the WPT signal, the second bias voltage V for the output side WPT D2B and switching between the second bias & matching circuit 1323(2) for output side communication and the second bias & matching circuit 1323′(2) for output side WPT so as to use the matching circuit B for output side WPT.

[0104] 1 to 27 configured as described above, in downlink communication from the base station 10 to the UE 20, wireless resources unused for communication can be effectively utilized as wireless power transmission blocks (WPT blocks), and wireless power transmission (WPT) can be performed from the base station 10 to the UE 20. In addition, it is possible to increase the output power and efficiency of the outphasing amplifier (power amplifier) ​​131 when amplifying a WPT signal in the base station 10.

[0105] 28 is an explanatory diagram showing an example of power supply for each UE by beamforming from a base station 10 to multiple UEs 20 according to this embodiment. In this embodiment, as shown in FIG. 28, multiple UEs 20(1) to 20(3) are present in a WPT area 10A' (see FIG. 1 above) within a communication area 10A, and power may be supplied to each UE 20(1) to 20(3) via beams 10B(1) to 10B(3) formed for each UE. The beams 10B(1) to 10B(3) may be formed by switching between them in a time-division manner, for example.

[0106] Machine learning may be used to adjust and set the susceptance value of the reactance compensation circuit in accordance with the peak-to-average power ratio (PAPR) for each of the communication signal and the wireless power transmission signal.

[0107] As described above, according to the power amplifier circuit of the embodiment of the present disclosure, multiple signals (communication signals and WPT signals) separated on the time axis can be amplified with the desired input / output power characteristics (PAPR), and can also be configured using a single circuit module.

[0108] Furthermore, according to the base station and system of the embodiment of the present disclosure, by using a WPT signal having a lower PAPR than the communication signal, the base station 10 can amplify the communication signal within a low output power range with a large margin to prevent spurious signals from occurring, and can achieve high output and high efficiency in the power amplifier circuit when amplifying the WPT signal.

[0109] Furthermore, according to the base station and the system according to the embodiment of the present disclosure, it is possible to supply power to the terminal device 20 by utilizing radio resources that are not used in communication between the base station 10 and the terminal device 20 .

[0110] Furthermore, the power amplifier circuit and transmitter disclosed herein can amplify multiple signals separated on the time axis with the desired input / output power characteristics, 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 industrial and technological innovation."

[0111] It should be noted that the process steps and components of the power amplifier circuit, transmitter, base station, and system described herein can be implemented by various means, for example, these steps and components may be implemented in hardware, firmware, software, or a combination thereof.

[0112] For hardware implementation, the processing units and other means used to implement the above steps and components in an entity (e.g., various wireless communication devices, Node Bs, terminals, hard disk drive devices, or optical disk drive devices) may be implemented in one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processors (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, electronic devices, other electronic units designed to perform the functions described herein, computers, or combinations thereof.

[0113] Furthermore, with regard to firmware and / or software implementations, the means, such as a processing unit, used to realize the above components may be implemented with a program (e.g., code, such as procedures, functions, modules, instructions, etc.) that performs the functions described herein. In general, any computer / processor-readable medium tangibly embodying firmware and / or software code may be used to implement the means, such as a processing unit, used to realize the above steps and components described herein. For example, the firmware and / or software code may be stored in a memory and executed by a computer or processor, such as in a controller. The memory may be implemented within the computer or processor or external to the processor. Furthermore, the firmware and / or software code may be stored in a computer- or processor-readable medium, such as random access memory (RAM), read-only memory (ROM), non-volatile random access memory (NVRAM), programmable read-only memory (PROM), electrically erasable programmable read-only memory (EEPROM), flash memory, floppy disk, compact disk (CD), digital versatile disk (DVD), magnetic or optical data storage device, etc. 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.

[0114] The medium may be a non-transitory recording medium. The program code may be in any format as long as it can be read and executed by a computer, processor, or other device or machine. For example, the program code may be in any of source code, object code, and binary code, or may be a mixture of two or more of these codes.

[0115] Moreover, the description of the embodiments disclosed herein is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to the present 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 the present disclosure. Thus, the present disclosure is not intended 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. [Explanation of symbols]

[0116] 10:Base station 10A: Communication area 10A': WPT Area 10B: Beam 20: User Equipment (UE) 100:Base station equipment 101: Transmitter 110: Antenna (array antenna) 120: Communication signal processing section 121: Transmission signal detection unit 122: Transmission signal processing section 130: Radio processing unit 131: Outphasing amplifier 132(1): First amplifier (single power amplifier) 132(2): Second amplifier (single power amplifier) 133:Shiray Synthesis Device 134: Reactance compensation circuit 140: Control unit 141: Trigger signal 142: PAPR detection unit 1321: Input bias and matching circuit 1322: Power amplifier (FET) 1323: Output bias and matching circuit 1324: Input matching circuit selector switch 1325: Input bias switch 1326: Output matching circuit selector switch 1327: Output bias switch 1332: Impedance converter 1334: Reactance compensation circuit 1335: First reactance compensation circuit 1336: Second reactance compensation circuit 1337: Switch

Claims

1. 1. A power amplifier circuit, comprising: an outphasing amplifier including a first amplifier for amplifying a first signal having a first phase generated from a signal to be amplified, a second amplifier for amplifying a second signal having a second phase generated from the signal to be amplified and different from the first phase, and a Shereley combiner including a reactance compensation circuit provided between an output path of the first amplifier and an output path of the second amplifier; means for adjusting a susceptance value of the reactance compensation circuit in the Sherei combiner in accordance with a desired input / output power characteristic of the signal to be amplified; A power amplifier circuit comprising:

2. 2. The power amplifier circuit of claim 1, The signal to be amplified includes a first signal to be amplified and a second signal to be amplified, which are separated along a time axis and are amplified in a first region and a second region, respectively, having different outputs and efficiencies of input / output characteristics; The Shirei synthesizer comprises: a first reactance compensation circuit and a second reactance compensation circuit having different susceptance values; a first switch and a second switch that switch between the first reactance compensation circuit and the second reactance compensation circuit in accordance with a signal switching timing between the first signal to be amplified and the second signal to be amplified, A power amplifier circuit comprising:

3. 3. The power amplifier circuit of claim 2, the first reactance compensation circuit and the second reactance compensation circuit each include a capacitive reactance element having a fixed, semi-fixed, or variable capacitive susceptance value, and an inductive reactance element having a fixed, semi-fixed, or variable inductive susceptance value; the capacitive reactance element is provided so as to be connectable to an output path of the first amplifier via the first switch; the inductive reactance element is provided so as to be connectable to an output path of the second amplifier via the second switch; the intermediate connection point between the capacitive reactance element and the inductive reactance element is grounded; A power amplifier circuit comprising:

4. 4. The power amplifier circuit of claim 3, the capacitive reactance element is a variable capacitor or a varactor diode; the inductive reactance element is a variable inductor; A power amplifier circuit comprising:

5. 2. The power amplifier circuit of claim 1, the first amplifier and the second amplifier of the outphasing amplifier each include a power amplifying element, an input matching circuit provided on the input side of the power amplifying element, and an output matching circuit provided on the output side of the power amplifying element; A power amplifier circuit comprising:

6. A transmitter comprising: a communication signal processing unit that generates a communication signal and a wireless power transmission signal separately on a time axis; a wireless processing unit that amplifies the communication signal and the wireless power transmission signal generated by the communication signal processing unit along a time axis using a power amplifier circuit and transmits the amplified signal to a terminal device; The power amplifier circuit of the radio processing unit is the power amplifier circuit of claim 1 or 5, the signal to be amplified includes the communication signal and the wireless power transmission signal, which are amplified in a first region and a second region, respectively, having different input / output characteristics in terms of output and efficiency. A transmitter characterized by:

7. A base station comprising a transmitter, a receiver and an antenna, 7. A base station, wherein the transmitter is the transmitter of claim 6.

8. A transmitter, a communication signal processing unit that generates a communication signal and a wireless power transmission signal separately on a time axis; a wireless processing unit that amplifies the communication signal and the wireless power transmission signal generated by the communication signal processing unit along a time axis using a power amplifier circuit and transmits the amplified signal to a terminal device; The power amplifier circuit of the radio processing unit is a power amplifier circuit according to claim 2, 3 or 4, the signal to be amplified includes the communication signal and the wireless power transmission signal, which are amplified in a first region and a second region, respectively, having different input / output characteristics in terms of output and efficiency. A transmitter characterized by:

9. A base station comprising a transmitter, a receiver, and an antenna, 9. A base station, wherein the transmitter is the transmitter of claim 8.

10. 10. The base station of claim 9, the wireless processing unit switches between the first reactance compensation circuit and the second reactance compensation circuit in the Shelay combiner in accordance with signal timings of the communication signal and the wireless power transmission signal. A base station characterized by:

11. 11. The base station of claim 10, the communication signal processing unit detects the communication signal and the wireless power transmission signal, and outputs a trigger signal corresponding to a signal switching timing between the communication signal and the wireless power transmission signal; the wireless processing unit switches between the first reactance compensation circuit and the second reactance compensation circuit in accordance with signal timings of the communication signal and the wireless power transmission signal based on a trigger signal output from the communication signal processing unit, so as to use the first reactance compensation circuit when amplifying the communication signal and the second reactance compensation circuit when amplifying the wireless power transmission signal. A base station characterized by:

12. 12. The base station of claim 11, The wireless processing unit adjusting a susceptance value of the first reactance compensation circuit in accordance with a peak-to-average power ratio (PAPR) of the communication signal; adjusting a susceptance value of the second reactance compensation circuit in accordance with a peak-to-average power ratio (PAPR) of the wireless power transmission signal; A base station characterized by:

13. 11. The base station of claim 10, the communication signal processing unit detects the communication signal and the wireless power transmission signal, and outputs a trigger signal corresponding to a signal switching timing between the communication signal and the wireless power transmission signal; the wireless processing unit switches the input-side and output-side bias voltages and the input-side and output-side matching circuits in accordance with the signal timing of the communication signal and the wireless power transmission signal, based on the trigger signal output from the communication signal processing unit, so as to use bias voltages for input-side communication and output-side communication and matching circuits for input-side communication and output-side communication when amplifying the communication signal, and to use bias voltages for input-side wireless power transmission and output-side wireless power transmission and matching circuits for input-side wireless power transmission and output-side wireless power transmission when amplifying the wireless power transmission signal. A base station characterized by:

14. A system for performing communication between a base station and a terminal device and wireless power transmission from the base station to the terminal device, The base station is the base station of claim 7. A system characterized by:

15. A system for performing communication between a base station and a terminal device and wireless power transmission from the base station to the terminal device, comprising: The base station is the base station of claim 9. A system characterized by:

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