Wireless communication device, airborne wireless relay device, communication system, and method and program for controlling wireless communication device.

Abstract

The present invention provides a wireless communication device that can reduce overall power consumption while minimizing weight, and that can ensure reliable and safe startup in the extremely low-temperature environment of the upper atmosphere. [Solution] The wireless communication device comprises a power supply unit, an amplifier that can be controlled to switch between operating as a heater mode and operating as a communication mode for amplifying high-frequency signals, and a main control unit that is powered by the power supply unit when the amplifier, which is operating as a heater mode when the wireless communication device is started up, heats up to a predetermined temperature, and controls the operation mode of the amplifier to switch to the communication mode.

Description

[Technical Field]

[0001] This disclosure relates to a wireless communication device having an amplifier for amplifying high-frequency signals, an airborne wireless relay device, a communication system, and a method and program for controlling a wireless communication device. [Background technology]

[0002] Conventionally, there are known aerial-based wireless relay devices equipped with wireless communication equipment (relay communication stations) that have high-frequency amplifiers.

[0003] Patent Document 1 discloses a wireless relay device such as a High Altitude Platform Station (HAPS) (also called a "High Altitude Pseudo-Satellite") that is equipped with a wireless communication device (relay communication station) that stays in the stratospheric airspace at an altitude of 18 km or more and 50 km or less and relays wireless communication. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2025-185590 [Overview of the Initiative]

[0005] A wireless communication device according to one aspect of the present disclosure includes a power supply unit, an amplifier controllable to switch between operating as a heater mode and operating as a communication mode for amplifying high-frequency signals, and a main control unit that is powered by the power supply unit when the amplifier, which is operating as a heater mode when the wireless communication device is started up, heats up to a predetermined temperature, and controls the amplifier to switch its operating mode to the communication mode.

[0006] The wireless communication device may include a bias control unit that is constantly powered from the power supply unit, the main control unit transmits a control command to the bias control unit to switch from the heater mode to the communication mode when heated to a predetermined temperature, the bias control unit applies a heater mode bias to the amplifier to operate the amplifier as a heater in the heater mode, and, based on the control command received from the main control unit, applies a communication mode bias to the amplifier to operate the amplifier in the communication mode.

[0007] The wireless communication device includes a first temperature sensor for detecting the temperature of the main control unit, and an analog comparator for comparing the output of the first temperature sensor with a reference value corresponding to the minimum startup temperature of the main control unit. The power supply unit may start supplying power to the main control unit when the output of the first temperature sensor becomes equal to or greater than the reference value, based on the comparison result of the analog comparator.

[0008] In the wireless communication device, the power supply unit may supply an idle current equivalent to Class A to the amplifier when the heater mode is in operation.

[0009] The wireless communication device may include an input unit provided before the amplifier to block the input of a high-frequency signal to the amplifier when the heater mode is in operation, and an output unit provided between the amplifier and the antenna to block the output of a high-frequency signal from the amplifier when the heater mode is in operation.

[0010] In the wireless communication device, the power supply unit may output a main drive bias for primarily driving the amplifier, and may also include a temperature switch that cuts off the application of the main drive bias from the power supply unit to the amplifier when the amplifier's temperature rises excessively.

[0011] The wireless communication device includes a second temperature sensor for detecting the temperature of the amplifier or its surroundings, and an analog comparator for comparing the output of the second temperature sensor with a reference value corresponding to the upper limit temperature of the amplifier. The power supply unit outputs a main drive bias for primarily driving the amplifier, and may stop outputting the main drive bias when the output of the second temperature sensor exceeds the reference value based on the comparison result of the analog comparator.

[0012] The wireless communication device may include a heat pipe that transmits heat from the amplifier to the main control unit.

[0013] The wireless communication device may include a plurality of amplifiers, and these plurality of amplifiers may be operated sequentially in heater mode using a time-division multiplexer.

[0014] Another embodiment of the present disclosure is an airborne wireless relay device installed on an aircraft or levitation vehicle capable of staying in the air. This wireless relay device comprises a service link transmitting unit that transmits a service link high-frequency signal to a terminal device, and a feeder link transmitting unit that transmits a feeder link high-frequency signal to a gateway device on the communication network side. The service link transmitting unit and the feeder link transmitting unit each have one of the wireless communication devices described above.

[0015] A communication system according to yet another aspect of this disclosure comprises the above-ground-station type wireless relay device and a gateway device on the communication network side that performs wireless communication of a feeder link with the wireless communication device.

[0016] A method relating to yet another aspect of the present disclosure is a method for controlling a wireless communication device. This method includes controlling an amplifier in the wireless communication device to switch between operating in a heater mode, which operates as a heater, and in a communication mode, which amplifies a high-frequency signal, and supplying power to a main control unit and switching the operating mode of the amplifier to the communication mode when the amplifier, which is operating in heater mode when the wireless communication device is started up, heats up to a predetermined temperature.

[0017] A program according to still another aspect of the present disclosure is a program executed by a computer or a processor provided in a wireless communication device. This program includes program code for controlling an amplifier included in the wireless communication device to operate by switching between a heater mode in which the amplifier operates as a heater and a communication mode in which a high-frequency signal is amplified, and when the amplifier operated in the heater mode is heated to a predetermined temperature at startup of the wireless communication device, program code for supplying power to the main control unit and controlling the operation mode of the amplifier to be switched to the communication mode.

[0018] Note that the program for performing control and the like of the present disclosure may include a pre-learning model used for machine learning or a learned model created by machine learning (for example, a model used for AI provided in the aforementioned wireless communication device or wireless relay device).

Brief Description of the Drawings

[0019] [Figure 1] FIG. 1 is an explanatory diagram showing an example of the overall configuration of a communication system including an airborne wireless relay device according to an embodiment. [Figure 2] FIG. 2(a) is an explanatory diagram showing an example of a repeater system using a non-regenerative wireless relay device. FIG. 2(b) is an explanatory diagram showing an example of a base station system using a regenerative wireless relay device. [Figure 3] FIG. 3 is a block diagram showing a configuration example of a wireless relay device of a communication system according to an embodiment. [Figure 4] FIG. 4 is a block diagram showing an example of the main configuration of a wireless communication device provided in a wireless relay device according to an embodiment. [Figure 5] FIG. 5 is a diagram showing an example of a FET used in an amplifier of a wireless communication device. [Figure 6] FIG. 6 is a flowchart showing an example of a startup sequence of a wireless communication device according to an embodiment.

Embodiments for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Each drawing in the drawings only schematically shows the shape, size, positional relationship, correspondence relationship, configuration, processing, steps, procedures, etc. to the extent that the content of the present disclosure can be understood. Therefore, the present disclosure is not limited to only the shape, size, positional relationship, correspondence relationship, configuration, processing, steps, and procedures illustrated in each drawing. Also, the numerical values exemplified in the present disclosure are only preferred examples, and thus the present disclosure is not limited to the exemplified numerical values.

[0021] The device according to an embodiment of the present disclosure is a wireless communication device that can reduce the total power consumption while achieving weight reduction, and can ensure the certainty and safety of startup in the extremely low temperature environment in the sky.

[0022] FIG. 1 is an explanatory diagram showing an example of the overall configuration of a communication system including an airborne relay type wireless relay device (relay communication station) 110 according to an embodiment of the present disclosure. The wireless relay device (relay communication station) 110 in FIG. 1 is a frequency conversion type wireless relay device (relay communication station) that uses different frequency bands for the feeder link and the service link. Note that FIG. 1 shows an example of a communication system with a single cell configuration corresponding to a single base station device 80, but the communication system of the present disclosure may be a communication system with a multi-cell configuration forming a plurality of cells. Also, the communication system of the present disclosure is suitable for realizing a three-dimensional network of fourth-generation, fifth-generation, or subsequent-generation mobile communications that can support simultaneous connection to a plurality of terminal devices (hereinafter also referred to as "UE" (user devices)) 60 and low latency. Also, the standard specifications of mobile communications applicable to the communication system, wireless relay device, base station device, gateway device, and terminal device of the present disclosure may be the standard specifications of fourth-generation or fifth-generation mobile communications, and the standard specifications of mobile communications of generations after the fifth generation.

[0023] As shown in Figure 1, the communication system of this disclosure includes a high-altitude platform station (HAPS) 10 (also called a "high-altitude pseudo-satellite" or "stratospheric platform") having an airborne stationary radio relay device (relay communication station) 110 that constitutes an airborne platform. The HAPS 10 is an airborne stationary (also called an "airborne floating" communication platform) located in the airspace at a predetermined altitude, and forms a three-dimensional cell (three-dimensional area) 20C in the target airspace for cell formation from the target service area 20A to the predetermined altitude.

[0024] HAPS10 is a flying or floating vehicle 100 that is controlled to float or fly in high-altitude airspace (float airspace) at an altitude of 100 km or less above the ground or sea surface by autonomous control or external control, and is equipped with a radio relay device (hereinafter also referred to as a "relay communication station") 110. The airspace in which HAPS10 is located may be, for example, stratospheric airspace at altitudes of 18 km or more and 50 km or less. This airspace may also be airspace at altitudes of 15 km or more and 25 km or less where meteorological conditions are relatively stable, and in particular, airspace at an altitude of approximately 20 km.

[0025] The target airspace for cell formation in HAPS10 may be a predetermined altitude range (for example, an altitude range from the ground up to 1000m or up to 1000m) located between the airspace where HAPS10 is located and the near-ground cell formation area covered by conventional base stations such as macrocell base stations (e.g., LTE eNodeB or next-generation gNodeB).

[0026] The target airspace for cell formation may be over the sea, a river, or a lake. Furthermore, the three-dimensional cell formed by HAPS10 may be formed to reach the ground or sea surface so that it can communicate with UEs (terminal devices) 60 located on the ground or at sea.

[0027] HAPS10 communicates wirelessly with UE60 via a service link antenna (hereinafter also referred to as "SL antenna") 111 of a relay communication station 110 installed on an aircraft 100 such as a flying object or floating object located in the air. HAPS10 can fly on electricity, for example, by being equipped with at least one of a battery and a solar power generation system. HAPS10 may be a solar-powered plane type HAPS as shown in the figure, or an airship type HAPS. Furthermore, the HAPS10 on which the relay communication station 110 is installed may be an artificial satellite (e.g., a communications satellite), a balloon, or an unmanned aerial vehicle (UAV) such as a drone or UAS (Unmanned Aircraft Systems). HAPS10 may also fly with at least one of a battery and an engine as its power source. The UAV may be, for example, an unmanned aircraft that flies on fuel, or a drone that flies on a battery, etc.

[0028] The relay communication station 110 includes an SL antenna 111 used for the service link of the service radio section and a feeder link antenna (hereinafter also referred to as "FL antenna") 112 used for the feeder link of the relay radio section. The relay communication station 110 can communicate with the UE 60 via the SL antenna 111 over the service link SL. The SL antenna 111 is, for example, a beamforming controllable array antenna that can control the direction and width of the beam that forms a cell 20C in the target service area 20A. The area through which the beam passes in the target airspace for cell formation is the three-dimensional cell 20C. The footprint 20F is a set of communication areas where the cell 20C has reached the ground (or sea, etc.).

[0029] The radio waves transmitted or received by the relay station 110 of this disclosure are, for example, microwaves, millimeter waves, or submillimeter waves of 300 MHz or higher.

[0030] The SL antenna 111 may be a beamforming-controllable array antenna capable of controlling the direction and width of each of the multiple beams that form multiple cells (e.g., 3 cells or 7 cells) in the target service area 20A. Multiple beams adjacent to each other in the target airspace for cell formation may partially overlap.

[0031] The relay communication station 110 can communicate via feeder link FL with a gateway device for HAPS (also called a "feeder station"; hereinafter referred to as a "GW station") 70 located on land (or at sea, etc.) via the FL antenna 112. The FL antenna 112 is, for example, an array antenna whose directivity (direction of the directional beam) can be controlled.

[0032] The SL antenna 111 and the FL antenna 112 are, for example, single or multiple array antennas in which multiple antenna elements are arranged two-dimensionally or three-dimensionally, and which are capable of forming multiple beams toward the ground. The SL antenna 111 and the FL antenna 112 may also be massive antennas in which a large number of antenna elements are arranged two-dimensionally, and which can control the beam directivity in the horizontal and vertical directions.

[0033] GW station 70 can communicate with relay communication station 110 via feeder link FL via feeder link antenna (hereinafter also referred to as "FL antenna") 71. The FL antenna 71 is, for example, an antenna whose directivity (direction of the directional beam) can be controlled. The FL antenna 71 is, for example, a single or multiple array antenna in which a plurality of antenna elements are arranged two-dimensionally or three-dimensionally. The FL antenna 71 may also be a massive antenna in which a large number of antenna elements are arranged two-dimensionally and whose horizontal and vertical directivity can be controlled.

[0034] In Figure 1, feeder link FL(F) and service link SL(F) are forward links (hereinafter also referred to as "downlinks") from GW station 70 to UE60 via HAPS10. Feeder link FL(R) and service link SL(R) are reverse links (hereinafter also referred to as "uplinks") from UE60 to GW station 70 via HAPS10.

[0035] UE60 is a terminal device used by users on land or at sea. Examples of UE60s include mobile phones, smartphones, and portable personal computers with mobile communication capabilities. They are also called mobile terminals, mobile stations, mobile devices, or portable communication terminals. UE60s may also be modular mobile stations integrated into vehicles such as automobiles, or aircraft such as drones (which are remotely controlled small helicopters), or they may be terminal devices for IoT (Internet of Things) applications.

[0036] UE60 can communicate with base station equipment 80 connected to the core network 85 of the mobile communication network using the FDD (Frequency Division Duplex) method via relay station 110 and GW station 70. UE60 can also access external communication networks 90, such as the Internet, via base station equipment 80 and the core network 85 of the mobile communication network.

[0037] In the communication system of this embodiment, for example, FDD (Frequency Division Duplex) communication is performed in each radio section between the base station equipment 80 and the UE (terminal equipment) 60. That is, the duplexing of the downlink (forward link) and uplink (reverse link) of the service link between the relay communication station 110 and the UE 60, the duplexing of the downlink (forward link) and uplink (reverse link) between the base station equipment 80 and the GW station 70, and the duplexing of the downlink (forward link) and uplink (reverse link) between the relay communication station 110 and the GW station 70 are all FDD (Frequency Division Duplex).

[0038] For example, a first frequency band for service links (e.g., 900 MHz band (Band 8)) is used in the service radio section between the antenna 61 of the terminal device 60 and the SL antenna 111 of the relay communication station 110. The first frequency band has an FDD downlink band (hereinafter also referred to as the "downlink band") in which multiple frequency channels of a predetermined bandwidth (e.g., 5 MHz) are arranged adjacent to each other, and an FDD uplink band (hereinafter also referred to as the "uplink band") in which multiple frequency channels of a predetermined bandwidth (e.g., 5 MHz) are arranged adjacent to each other, separated by a predetermined guard band. The first frequency channel of the downlink band of the first frequency band is used for forward link radio communication, and the first frequency channel of the uplink band of the first frequency band is used for reverse link radio communication.

[0039] A relay communication station 110 that uses different frequency bands for the service radio section (service link) and the feeder radio section (feeder link) can be used even when the service radio section and the feeder radio section spatially overlap. Furthermore, since no interference leakage occurs at the relay communication station 110, an interference leakage canceller is unnecessary.

[0040] The access method for wireless communication between the base station equipment 80 and the UE60 via the relay station 110 and the GW station 70 is not limited to a specific method, and may be, for example, FDMA (Frequency Division Multiple Access), TDMA (Time Division Multiple Access), CDMA (Code Division Multiple Access), or OFDMA (Orthogonal Frequency Division Multiple Access).

[0041] Furthermore, for the wireless communication of the service link between the relay station 110 and the UE60, MIMO (Multi-Input and Multi-Output) technology may be used, which has functions such as diversity coding, transmit beamforming, and spatial division multiplexing (SDM), and which can increase the transmission capacity per unit frequency by simultaneously using multiple antennas for both transmission and reception. In addition, the MIMO technology may be SU-MIMO (Single-User MIMO) technology in which one base station transmits multiple signals to one UE at the same time and frequency, or MU-MIMO (Multi-User MIMO) technology in which one base station transmits signals to multiple different UEs at the same time and frequency, or multiple different base stations transmit signals to one UE at the same time and frequency.

[0042] In the communication system with the above configuration, for example, signals from the base station equipment 80 are relayed by the GW station 70 and the HAPS 10 relay communication station 110, enabling communication services to be provided to the UE 60 on the ground. In particular, according to the communication system of this embodiment, the HAPS 10, which functions as an aerial platform, can directly provide ultra-wide-area mobile communication services from the stratosphere at altitudes of 18 km or higher and 50 km or lower (especially around 20 km) to the UE (terminal equipment) 60 on the ground. Furthermore, the aerial platform consisting of the HAPS 10 is attracting attention as a new communication form for use in large-scale disasters and other similar situations.

[0043] The relay communication station (wireless relay device) 110 mounted on the HAPS10 aircraft 100 is a non-regenerative type (hereinafter also referred to as "repeater type") relay communication station that relays transmitted and received signals without regenerating them. Generally, there are two types of wireless relay systems via the HAPS10 relay communication station 110: the repeater system shown in Figure 2(a) and the base station system shown in Figure 2(b). In the repeater system shown in Figure 2(a), the relay communication station 110 mounted on the HAPS10 aircraft 100 functions as a non-regenerative repeater, directly relaying communication between the base station equipment 80 and the UE60 via a bent-pipe-like path through the GW station 70 and the relay communication station 110. The repeater system shown in Figure 2(a) is advantageous for reducing the weight and power consumption of the relay communication station (wireless relay device) 110 because the base station equipment 80 can be installed on the ground, and it also facilitates multi-operator operation. On the other hand, in the base station system shown in Figure 2(b), the relay station 110 mounted on the HAPS10 aircraft 100 has a base station device 80, and the base station device 80 of the relay station 110 is connected to the core network 85 of the mobile communication network via a backhaul line such as FWA, and regenerates the transmitted and received signals to perform wireless communication with the UE60. In the base station system shown in Figure 2(b), the equipment configuration of the relay station 110, including the base station device 80, is complex, which is disadvantageous for weight reduction and low power consumption, and multi-operator operation is difficult.

[0044] Figure 3 is a block diagram showing an example configuration of a wireless relay device (relay station) 110 in a communication system according to an embodiment of the present disclosure. In Figure 3, the relay station 110 includes an SL antenna 111, an FL antenna 112, duplexers 113 and 114, a forward link signal path 115, and a reverse link signal path 116. The forward link signal path 115 includes a low-noise amplifier (LNA) 1151, a signal processing unit 1152, and a high-frequency amplifier, which is a power amplifier (PA) 1153. The reverse link signal path 116 includes a low-noise amplifier (LNA) 1161, a signal processing unit 1162, and a high-frequency amplifier, which is a power amplifier (PA) 1163.

[0045] At the relay station 110, a predetermined feeder link frequency f is received from the FL antenna 71 of the GW station 70 via the FL antenna 112 and the duplexer 113. FL The forward link (downlink) received signal is amplified by the LNA1151 and frequency converted (f FL →f SL The signal is processed by a signal processing unit 1152 which has the functions of a digital filter and a predetermined service link frequency f. SL The forward link (downlink) signal, converted to this format, is amplified to a predetermined power level by PA1153 and transmitted via duplexer 114 from SL antenna 111 to antenna 61 of terminal device 60. Additionally, a predetermined service link frequency f is received from antenna 61 of terminal device 60 via SL antenna 111 and duplexer 114. SL The received signal from the reverse link (uplink) is amplified by the LNA1161 and frequency converted (f SL →f FL ) and the signal processing unit 1162, which has the function of a digital filter, are processed. A predetermined feeder link frequency f FL The reverse link (uplink) signal, converted to the reverse link, is amplified to a predetermined power level by PA1163 and transmitted via duplexer 113 to the FL antenna 71 of GW station 70.

[0046] In the communication system of the embodiments of this disclosure, when a wireless communication device is mounted on a wireless relay device (relay communication station) 110 used in an extremely low-temperature environment (e.g., the stratosphere at approximately -70°C or below), it is difficult to start up digital circuits such as CPUs / FPGAs that constitute the control unit at low temperatures. Conventionally, the minimum temperature above a predetermined temperature was ensured by a combination of a dedicated heater (e.g., a resistance heater) and an insulating structure while monitoring with a temperature sensor, and the digital circuits were started up. The RF system that processes high-frequency signals is activated sequentially after the digital circuits are started up, and the PA and LNA used in the wireless communication device operate with the normal communication bias. In some operations, a method is also seen in which a dedicated heater is driven for a fixed time without using a temperature sensor to ensure the minimum temperature and start up the digital circuits.

[0047] However, when using the dedicated heater described above to perform low-temperature startup, the following issues A1 to A4 arise. A1. Weight: The mass of the wireless relay device (relay station) increases due to the dedicated heater and its wiring, the fixing device for the dedicated heater, and the drive control circuit for the dedicated heater. A2. Power Consumption: In configurations with high heat dissipation, heater power becomes excessive, increasing the power consumption of the wireless relay equipment (relay communication station). A3. Number of parts: The number of parts that make up the wireless relay device (relay communication station) increases due to the addition of dedicated heaters and other components, which is disadvantageous in terms of reliability and cost. A4. Uncertainty of fixed-time control: When a dedicated heater is driven for a fixed time, fluctuations in environmental conditions can cause overheating or underheating, which can lead to startup failures or wasted power consumption.

[0048] In particular, for solar-plane type HAPS, weight reduction and low power consumption are crucial, and a new method is needed that reduces the number of dedicated heaters while improving the reliability of low-temperature startup.

[0049] In the embodiments of this disclosure, in order to overcome the problems of low-temperature startup that rely on conventional dedicated heaters, a high-frequency amplifier used in at least one of the driver stage and power amplifier stage is self-heated in heater mode (no signal, high idle current), and when the digital circuit of the control unit reaches a predetermined startup temperature, the main power supply is activated to start the digital circuit of the control unit, and after startup, it switches to communication mode. This reduces the number of components such as dedicated heaters and wiring, making the device lighter, while reducing total power consumption by dual utilization of power, and improving startup reliability and safety by suppressing the uncertainty of fixed-time control.

[0050] Figure 4 is a block diagram showing an example of the main configuration of a wireless communication device 1000 provided in a wireless relay device (relay communication station) 110 according to an embodiment of the present disclosure. The wireless communication device 1000 is, for example, a device that includes a power amplifier (PA) 1153, a power amplifier (PA) 1163, or both, as high-frequency amplifiers that constitute the power amplifier stage of the wireless relay device (relay communication station) 110 in Figure 3. If the wireless relay device (relay communication station) 110 has a driver stage, the wireless communication device 1000 may also include a power amplifier (PA) that constitutes the driver stage. The high-frequency amplifier in the wireless communication device 1000 may be an amplifier other than a power amplifier (PA), such as an LNA. The wireless communication device 1000 may include a plurality of high-frequency amplifiers.

[0051] In Figure 4, the wireless communication device 1000 comprises a high-frequency (RF) amplifier 1001, a power supply unit 1002, and a main control unit 1003. The RF amplifier 1001 is composed of, for example, a high-frequency field-effect transistor (FET) 1001a made of GaN or GaAs (see Figure 5).

[0052] The RF amplifier 1001 is a controllable amplifier that can switch between a heater mode, where it operates as a heater, and a communication mode, where it amplifies high-frequency signals (hereinafter also referred to as "RF signals"). In heater mode, the RF amplifier 1001 operates with a high idle current and heats the surroundings through self-heating. Here, the idle current is the drain quiescent current (Idq) when there is no signal. The heat generated is roughly expressed as P ≈ Vdd × Idq. In communication mode, the RF amplifier 1001 operates with specified gain and linearity.

[0053] The power supply unit 1002 consists of, for example, a DC-DC converter and a PMIC (Power Management IC), and generates and controls the power supply (voltage, current) supplied to each part of the wireless communication device 1000.

[0054] The power supply unit 1002 has the following three power supply systems: (i) to (iii). (i) Power supply system for the main drive power supply of RF amplifier 1001 (power supply system for the drain bias Vdd of RF amplifier 1001 (hereinafter also referred to as "PA Vdd")) (ii) Power supply system for AON power supply (a constant power supply system that drives the analog comparator 1006 and gate bias control unit 1004 from before startup) (iii) Power supply system for the main power supply (power supply system for the main control unit (MCU / FPGA) 1003: power supply system for MAIN Vdd)

[0055] Based on the comparison results of the analog comparator 1006, the power supply unit 1002 activates the third MAIN Vdd and begins supplying power to the main control unit 1003. The first PA Vdd is supplied from the start of heater mode. The thermostat 1010 cuts off the power supply to the RF amplifier 1001 (power supply to drain bias Vdd) in the event of overheating.

[0056] The power supply unit 1002 may supply an idle current equivalent to Class A to the RF amplifier 1001 when operating in heater mode.

[0057] The main control unit 1003 is composed of, for example, an MCU (Microcontroller Unit) or an FPGA. When the RF amplifier 1001 is operated in heater mode during the startup of the wireless communication device 1000, the main control unit 1003 is powered by the power supply unit 1002 when it is heated to a predetermined temperature (for example, minus 40°C), and controls the RF amplifier 1001 to switch its operating mode to communication mode.

[0058] The wireless communication device 1000 may include a gate bias control unit 1004 that is constantly powered from the AON power supply of the power supply unit 1002. The main control unit 1003 transmits a control command for switching from the heater mode to the communication mode when heated to the predetermined temperature to the gate bias control unit 1004. The gate bias control unit 1004 applies a gate bias Vgs for the heater mode that operates the RF amplifier 1001 as a heater to the RF amplifier 1001 in the heater mode, and applies a gate bias Vgs for the communication mode that operates the RF amplifier 1001 in the communication mode to the RF amplifier 1001 based on the control command received from the main control unit 1003.

[0059] The wireless communication device 1000 includes a first temperature sensor 1005 that detects the temperature of the main control unit 1003, and an analog comparator 1006 that compares the output of the first temperature sensor 1005 with a reference value corresponding to the minimum startup temperature (T CPU_min )(e.g., minus 40 °C) of the main control unit 1003. The analog comparator 1006 outputs an activation signal for the MAIN power supply of the power supply unit 1002 when the output (control board temperature) of the first temperature sensor 1005 becomes equal to or higher than the reference value. The power supply unit 1002 may start supplying power to the main control unit 1003 when the output (control board temperature) of the first temperature sensor 1005 becomes equal to or higher than the reference value based on the comparison result of the analog comparator 1006. <​​​​​The wireless communication device 1000 may include an input section 1008 located before the RF amplifier 1001. The input section 1008 is, for example, an RF mute switch that blocks the input of an RF signal (transmission signal) to the RF amplifier 1001 when the heater mode is in operation (RF mute). By blocking the input and output of the RF signal in heater mode with the input section 1008, unwanted radio wave radiation and oscillation can be prevented.

[0062] The wireless communication device 1000 may include an output unit 1009 provided between the RF amplifier 1001 and the antenna 111. The output unit 1009 is composed of, for example, an output termination, a switch, or an isolator, and blocks the output of the RF signal (transmit signal) from the RF amplifier when the heater mode is operating. Stability can be ensured by terminating or disconnecting the output of the RF signal in heater mode with the output unit 1009.

[0063] The power supply unit 1002 outputs a drain bias Vdd as the main drive bias for primarily driving the RF amplifier 1001. The wireless communication device 1000 may also be equipped with a thermostat 1010 as a temperature switch that cuts off the application of the drain bias Vdd (main drive bias) from the power supply unit 1002 to the RF amplifier 1001 when the temperature of the RF amplifier 1001 rises excessively. The thermostat 1010 is a fail-safe temperature switch inserted in series with the drain power supply (Vdd) line from the power supply unit 1002 to the RF amplifier 1001 and cuts off the power supply to the RF amplifier 1001 when it overheats.

[0064] The wireless communication device 1000 may also include a second temperature sensor 1007 that detects the temperature of the RF amplifier 1001 or its surroundings. In this case, the analog comparator 1006 compares the output of the second temperature sensor 1007 with a reference value corresponding to the upper limit temperature of the RF amplifier 1001. Based on the comparison result of the analog comparator 1006, the power supply unit 1002 stops the output of the drain bias (main drive bias) Vdd when the output of the second temperature sensor 1007 becomes equal to or greater than the reference value.

[0065] When the main control unit 1003 is not started, the second temperature sensor 1007 is directly connected to the analog comparator 1006. After the main control unit 1003 is started, the output of the second temperature sensor 1007 is used for temperature monitoring by the main control unit 1003 via an ADC (analog-to-digital converter).

[0066] The wireless communication device 1000 may be equipped with a heat pipe to efficiently heat and maintain the main control unit 1003 using the heat from the RF amplifier 1001, thereby transferring heat from the RF amplifier 1001 to the main control unit 1003. Alternatively, the wireless communication device 1000 may be equipped with multiple RF amplifiers 1001, which may be operated sequentially in heater mode using time-division multiplexing.

[0067] In the wireless communication device 1000 shown in Figure 4, the main control unit 1003 may control the setting of the gate bias voltage Vgs of the power supply unit 1002 via the gate bias control unit 1004, or it may control the RF switches of the input unit 1008 and the output unit 1009. The main control unit 1003 may also acquire information on various states (for example, the quiescent drain voltage Idq of the RF amplifier 1001, gate bias Vgs, drain bias Vdd, FAULT (fault / protection state)) via telemetry from the gate bias control unit 1004.

[0068] Figure 6 is a flowchart showing an example of the startup sequence of a wireless communication device (relay station) 110 according to the embodiment of this disclosure. When the startup of the wireless communication device (relay station) 110 is initiated (S100), the RF amplifier 1001 in the wireless communication device 1000 mounted on the wireless communication device (relay station) 110 operates in heater mode (S101).

[0069] In heater mode (S101), no RF signal is input to the RF amplifier 1001, the gate bias Vgs and drain bias Vdd of the RF amplifier 1001 are set to voltages corresponding to high idle current, and the self-heating of the RF amplifier 1001 is used to heat the main control unit 1003.

[0070] The output of the first temperature sensor 1005, which detects the temperature of the control board constituting the main control unit 1003, is input to the analog comparator 1006, and the analog comparator 1006 determines that the temperature of the control board constituting the main control unit 1003 is a predetermined minimum startup temperature (T CPU_min (S102) Determine whether the temperature of the control board of the main control unit 1003 has reached a predetermined minimum startup temperature (T CPU_min The heater mode (S101) continues until it reaches (NO in S102).

[0071] The temperature of the control board of the main control unit 1003 reaches a predetermined minimum startup temperature (T CPU_min When the value reaches (YES in S102), the power supply system for the MAIN power supply (MAIN Vdd) of the power supply unit 1002 is turned ON, the MCU / FPGA on the control board of the main control unit 1003 starts up (S103), and the RF amplifier 1001 switches to communication mode and starts operating (S104).

[0072] In the above communication mode (S104), the gate bias Vgs (or both the gate bias Vgs and drain bias Vdd) of the RF amplifier 1001 is switched to the communication setting, the RF mute in the input section 1008 is released, enabling the transmission of RF signals, and the system transitions to communication operation (S200).

[0073] As described above, according to the embodiments of this disclosure, it is possible to reduce the total power consumption while making the wireless communication device (relay communication station) 110 mounted on the high-altitude wireless relay device (HAPS) 10 lighter, and to ensure the reliability and safety of starting up in the extremely low-temperature environment of the upper atmosphere (for example, the stratosphere at minus 70°C or below).

[0074] In particular, according to the embodiments of this disclosure, since there is no need to provide a dedicated heater in the wireless communication device 1000, the number of parts and wiring in the wireless communication device 1000 can be reduced, and the weight of the wireless communication device 1000 can be reduced.

[0075] In particular, according to the embodiments of this disclosure, the power supplied to the RF amplifier 1001 in the wireless communication device 1000 can be utilized in two ways (utilization for amplifying the RF signal and utilization for heat retention of the heat lost by the RF amplifier 1001).

[0076] In particular, according to the embodiments of this disclosure, the wireless communication device 1000 can be started up stably by determination by the analog comparator 1006, thereby achieving stability and reliability in the startup of the wireless communication device 1000.

[0077] In particular, according to the embodiments of this disclosure, safety can be ensured by a fail-safe mechanism for the RF amplifier 1001 using a thermostat 1010 in the wireless communication device 1000, thereby improving the reliability of the wireless communication device 1000.

[0078] Furthermore, the system disclosed herein can reduce the overall power consumption while making the wireless communication device lighter, and can ensure reliable and safe startup in the extremely low-temperature environment of the upper atmosphere, thus contributing to the achievement of Sustainable Development Goal (SDG) 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation."

[0079] In this specification, AI refers to artificial intelligence (including AGI or ASI) that generates content such as text, images, audio, and video using deep learning technologies such as transformers, self-attention, and autoregressive networks, including generative AI, language models (LLM / SLM), GPT®, Gemini®, Claude®, Llama®, and other language models. Extension technologies for generative AI include frameworks such as Search Augmentation Generation (RAG), Memory Augmentation Generation, hybrid search using vector databases, chunking / chunk processing, knowledge graph linking, entity linking, AutoGen, AOG, and LangChain. Performance improvement technologies for generative AI include fine tuning using RLHF / RLAIF, PEFT, LoRA, etc., distillation, quantization, weight sharing, continuous learning, associative learning, and in-context learning. Furthermore, the generating AI can operate in any environment, including on-premise, cloud, and edge (on-device), and parallel and distributed learning and inference using GPUs, TPUs, NPUs, IPUs, ASICs, and FPGAs are also possible.

[0080] The processing steps and components of the mobile communication 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.

[0081] With respect to hardware implementation, means such as processing units used to realize the above processes and components in a physical entity (e.g., various wireless communication devices, Node B, terminals, hard disk drive devices, or optical disc drive devices) may be implemented in one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (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.

[0082] Furthermore, with respect to the firmware and / or software implementation, means such as processing units used to realize the above-mentioned components may be implemented in the form of a program (e.g., code such as procedures, functions, modules, instructions, etc.) that performs the functions described herein. Generally, any computer / processor-readable medium that clearly embodies the firmware and / or software code may be used to implement means such as processing units used to realize the above-mentioned processes and components as described herein. For example, the firmware and / or software code may be stored in memory in a control device, for example, and executed by a computer or processor. That memory may be implemented inside the computer or processor, or it may be implemented outside the processor. Also, 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 PROM (EEPROM), flash memory, floppy disks, compact disks (CDs), digital versatile disks (DVDs), magnetic or optical data storage devices, etc. The code may be executed by one or more computers or processors, and the computers or processors may be made to perform functional embodiments as described herein.

[0083] Furthermore, the medium may be a non-temporary recording medium. Also, the program code may be readable and executable by a computer, processor, or other device or machine, and its format is not limited to a specific format. For example, the program code may be source code, object code, or binary code, or it may be a mixture of two or more of these codes.

[0084] Furthermore, the descriptions of embodiments disclosed herein are provided to enable those skilled in the art to manufacture or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the general principles defined herein are applicable to other variations without departing from the spirit or scope of the disclosure. Therefore, the disclosure is not limited to the examples and designs described herein, but should be accepted in the broadest sense that conforms to the principles and novel features disclosed herein. [Explanation of symbols]

[0085] 10: HAPS 20A: Service Area 20C: Cell 20F: Footprint 60: Terminal device 61: Antenna 70: GW Station 71: FL Antenna 80:Base station equipment 85: Core Network 90: Communication Network 100: Aircraft 110: Wireless relay equipment (relay communication station) 111: SL Antenna 112: FL antenna 113: Duplexa 114: Duplexa 115: Forward link signal path 116: Reverse link signal path 1000: Wireless communication device 1001: RF amplifier 1002: Power supply section 1003: Main Control Unit 1004: Gate bias control unit 1005: First temperature sensor 1006: Analog comparator 1007: Second temperature sensor 1008: Input section 1009: Output section 1010: Thermostat

Claims

1. A wireless communication device, Power supply unit, An amplifier that can be controlled to switch between a heater mode, which operates as a heater, and a communication mode, which amplifies high-frequency signals, A main control unit is powered by the power supply unit when the amplifier, which is operated in heater mode when the wireless communication device is started up, heats up to a predetermined temperature, and controls the amplifier to switch to the communication mode. A wireless communication device equipped with the following features.

2. In the wireless communication device of claim 1, It includes a bias control unit that is constantly powered from the aforementioned power supply unit, The main control unit transmits a control command to the bias control unit to switch from the heater mode to the communication mode when heated to the predetermined temperature. The bias control unit, In the heater mode, a heater mode bias is applied to the amplifier to operate it as a heater. Based on the control command received from the main control unit, a communication mode bias is applied to the amplifier to operate it in the communication mode. Wireless communication device.

3. In the wireless communication device of claim 1, A first temperature sensor that detects the temperature of the main control unit, The system includes an analog comparator that compares the output of the first temperature sensor with a reference value corresponding to the minimum startup temperature of the main control unit, The power supply unit starts supplying power to the main control unit when the output of the first temperature sensor becomes equal to or greater than the reference value, based on the comparison result of the analog comparator. Wireless communication device.

4. In the wireless communication device of claim 1, The power supply unit supplies an idle current equivalent to Class A to the amplifier when the heater mode is in operation. Wireless communication device.

5. In the wireless communication device of claim 1, An input section is provided in the preceding stage of the amplifier, which blocks the input of the transmission signal to the amplifier when the heater mode is in operation, An output unit is provided between the amplifier and the antenna, which blocks the output of the transmission signal from the amplifier when the heater mode is in operation, A wireless communication device equipped with the following features.

6. In the wireless communication device of claim 1, The power supply unit outputs a main drive bias primarily for driving the amplifier. The system includes a temperature switch that cuts off the application of the main drive bias from the power supply to the amplifier when the amplifier's temperature rises excessively. Wireless communication device.

7. In the wireless communication device of claim 1, A second temperature sensor for detecting the temperature of the amplifier or its surroundings, The system includes an analog comparator that compares the output of the second temperature sensor with a reference value corresponding to the allowable upper temperature limit of the amplifier, The aforementioned power supply unit is Outputting a main drive bias for primarily driving the aforementioned amplifier, Based on the comparison results of the analog comparator, when the output of the second temperature sensor exceeds the reference value, the output of the main drive bias is stopped. Wireless communication device.

8. In the wireless communication device of claim 1, The amplifier is equipped with a heat pipe that transmits heat to the main control unit. Wireless communication device.

9. In the wireless communication device of claim 1, The amplifier comprises multiple such amplifiers, The aforementioned multiple amplifiers are operated sequentially in heater mode using time division. Wireless communication device.

10. An airborne radio relay device installed on an aircraft or buoy capable of staying in the air, A service link transmission unit that transmits a high-frequency signal of the service link to a terminal device, It includes a feeder link transmission unit that transmits a high-frequency signal of the feeder link to a gateway device on the communication network side, The service link transmission unit and the feeder link transmission unit each have a wireless communication device according to any one of claims 1 to 8. Wireless relay device.

11. The above-ground wireless relay device according to claim 10, A communication system comprising a gateway device on the communication network side that performs wireless communication of a feeder link with the aforementioned wireless communication device.

12. A method for controlling a wireless communication device, The amplifier in the wireless communication device is controlled to switch between a heater mode, which operates as a heater, and a communication mode, which amplifies high-frequency signals. When the amplifier, which is operated in heater mode during the startup of the wireless communication device, heats up to a predetermined temperature, power is supplied to the main control unit, and the amplifier's operating mode is controlled to switch to the communication mode. Methods that include...

13. A program that is executed in a computer or processor installed in a wireless communication device, A program code for controlling the amplifier of the wireless communication device to switch between a heater mode, which operates as a heater, and a communication mode, which amplifies high-frequency signals, A program code for controlling the main control unit to switch the operating mode of the amplifier to the communication mode when the amplifier, which is operated in heater mode when the wireless communication device is started up, heats up to a predetermined temperature, and supplies power to the main control unit. A program that includes this.

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