Wireless communication system, wireless communication method, and wireless station

Abstract

A wireless communication system according to this embodiment is characterized by comprising: a weather radar antenna that is provided to a wireless station and transmits a signal from the wireless station to a node station and receives a reflected weather radar signal; a rainfall amount prediction unit that predicts the amount of rainfall between the wireless station and the node station on the basis of the weather radar signal received by the weather radar antenna; a quality prediction unit that predicts the quality of wireless communication between the wireless station and the node station on the basis of the amount of rainfall predicted by the rainfall amount prediction unit; and a switching control unit that, when the quality of wireless communication predicted by the quality prediction unit is lower than a predetermined threshold value, controls switching of a line connecting the node station and the wireless station to another line connecting the node station and another communication station before the line is disconnected.

Description

[Technical Field]

[0001] The present invention relates to a wireless communication system, a wireless communication method, and a wireless station. [Background technology]

[0002] In recent years, mobile communication systems have been developed to the point where mobile services can be enjoyed over most of the earth. Furthermore, one of the requirements for the 5th generation (Beyond 5G) or 6th generation mobile communication systems, which are expected to be commercialized in the future, is ultra-wide coverage.

[0003] Ultra-coverage refers to expanding the service area to areas where it is difficult or expensive to install existing base stations, such as mountains, oceans, and the air. There is also a need to strengthen the nation's resilience to natural disasters, and there is a need for a communications system that is resistant to terrestrial disasters.

[0004] To realize such wireless communication systems, non-terrestrial networks (NTNs) using geostationary satellites, medium-earth orbit (MEO) satellites, low-earth orbit (LEO) satellites, high-altitude platform stations (HAPS), unmanned aerial vehicles (UAVs), drones, etc. are attracting attention.

[0005] At NTN, the above-mentioned satellites and HAPS are connected to each other via communication links to form a network, which is then connected to the terrestrial mobile network via terrestrial base stations. The satellites and HAPS are equipped with mobile base station functions.

[0006] The communication link in HAPS consists of a feeder link (FL) between the HAPS and the terrestrial gateway station (ground station) on the ground communication network side, and a service link (SL) between the communication relay device and the terminal. For example, HAPS will be located at an altitude of approximately 20 km, and the ground area (cell) radius will be approximately 50 km. The HAPS service link is expected to use a 2 GHz frequency band, but the use of higher frequency millimeter waves (e.g., the 38 GHz band) for the feeder link is being considered.

[0007] Traffic packets sent from the terminal are then forwarded by the routing function to the HAPS, which is connected to the ground station, and sent to the Internet network. Packets sent from the Internet network to other terminals are also processed in the same way by the routing function.

[0008] NTN uses radio waves in the high frequency band, and it is anticipated that the quality of wireless communications will be degraded by rainfall. For example, if rainfall has an effect, there is a risk that service will be cut off on NTN's FL (feeder link), which uses high frequency bands.

[0009] Furthermore, fixed micro-radio systems used in sparsely populated suburban and rural areas also use relatively high frequency radio waves, and rainfall on the propagation path can degrade communication quality.

[0010] Therefore, there is a need for a configuration that takes into account the influence of weather such as rainfall to improve the availability of wireless communication systems.

[0011] For example, in order to improve the reliability of communications in the event of a disaster, a technique is known in which a base station, a control station, and a management station are each provided with a working and a backup device for performing supervisory control (for example, Non-Patent Document 1).

[0012] Furthermore, methods of observing precipitation using weather radar to take into account the effects of rainfall and methods of forecasting precipitation using weather radar are known (for example, Non-Patent Documents 2 and 3). [Prior art documents] [Non-patent literature]

[0013] [Non-Patent Document 1] Akira Matsushita and seven others, "Infrastructure Satellite Communication Systems Applied to Disaster Countermeasure Services," NTT Technical Journal, September 2005, pp. 14-17 [Non-patent document 2] "Rainfall Forecasting Method Using Weather Radar - Examination of Rainfall Calculation Method and Advection Model -", Research Report: U00050, Central Research Institute of the Electric Power Industry Report, Central Research Institute of the Electric Power Industry, April 2001 [Non-patent document 3] "Survey on the current status of research into precipitation observation and short-term rainfall forecasting using weather radar", Survey Report: U99041, Report of the Central Research Institute of the Electric Power Industry, Central Research Institute of the Electric Power Industry, March 2000 Summary of the Invention [Problem to be solved by the invention]

[0014] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a wireless communication system, a wireless communication method, and a wireless station that make it possible to prevent wireless communication from being interrupted due to the effects of weather. [Means for solving the problem]

[0015] A wireless communication system according to one embodiment of the present invention is a wireless communication system having a wireless station whose propagation path to a node station that relays wireless communication can be affected by weather, characterized in that the system comprises: a weather radar antenna provided in the wireless station and receives a weather radar signal transmitted from the wireless station toward the node station and reflected therefrom; a rainfall prediction unit that predicts the amount of rainfall between the wireless station and the node station based on the weather radar signal received by the weather radar antenna; a quality prediction unit that predicts the quality of wireless communication between the wireless station and the node station based on the amount of rainfall predicted by the rainfall prediction unit; and a switching control unit that, if the quality of wireless communication predicted by the quality prediction unit is below a predetermined threshold, controls to switch the line connecting the node station to the wireless station to another line connecting the node station to another communication station before the line is cut off.

[0016] Furthermore, a wireless communication method according to one embodiment of the present invention is a wireless communication method performed by a wireless communication system having a wireless station whose propagation path to a node station that relays wireless communication can be affected by weather, and is characterized by including: a rainfall prediction step of predicting the amount of rainfall between the wireless station and the node station based on a weather radar signal received by a weather radar antenna provided in the wireless station and which receives a weather radar signal transmitted from the wireless station toward the node station and reflected therefrom; a quality prediction step of predicting the quality of wireless communication between the wireless station and the node station based on the predicted rainfall; and a switching control step of, if the predicted quality of wireless communication is below a predetermined threshold, performing control to switch the line connecting the node station to the wireless station to another line connecting the node station to another communication station before the line is cut off.

[0017] Furthermore, a radio station according to one embodiment of the present invention is characterized in that, in a radio station where a propagation path between the radio station and a node station that relays radio communications can be affected by weather, the radio station comprises: a weather radar antenna that receives a weather radar signal that is transmitted toward the node station and reflected therefrom; a rainfall prediction unit that predicts the amount of rainfall between the radio station and the node station based on the weather radar signal received by the weather radar antenna; a quality prediction unit that predicts the quality of radio communications between the radio station and the node station based on the amount of rainfall predicted by the rainfall prediction unit; and a modem that, when the quality of radio communications predicted by the quality prediction unit is below a predetermined threshold, superimposes quality information, indicating that the quality of radio communications is below a predetermined threshold, on a control signal that the radio station transmits to the node station. [Effects of the Invention]

[0018] According to the present invention, it is possible to prevent wireless communication from being interrupted due to the influence of weather. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a diagram illustrating an example of the configuration of a wireless communication system according to an embodiment. [Figure 2] FIG. 2 is a block diagram illustrating an example of the configuration and functions of a wireless station. [Figure 3] FIG. 2 is a block diagram illustrating functions of a control station. [Figure 4] 1 is a flowchart illustrating an example of an operation of a wireless communication system according to an embodiment. [Figure 5] FIG. 2 is a diagram illustrating an example of a hardware configuration of a wireless station according to an embodiment. [Figure 6] FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system. DETAILED DESCRIPTION OF THE INVENTION

[0020] First, the background to the invention will be described. Fig. 6 is a diagram showing an example of the configuration of a wireless communication system 1. As shown in Fig. 6, the wireless communication system 1 is configured so that, for example, a plurality of wireless stations 2-1 to 2-3 can each perform wireless communication via a communication satellite 3.

[0021] The radio stations 2-1 to 2-3 are, for example, earth stations each having a base station function, and are connected to a mobile network (not shown). The communication satellite 3 is a node station that relays radio communications with each of the radio stations 2-1 to 2-3.

[0022] For example, suppose that rain occurs between the wireless station 2-1 and the communication satellite 3 in the wireless communication system 1. The wireless station 2-1 monitors the quality of wireless communication with the communication satellite 3 in real time, and when the quality of wireless communication deteriorates, performs site diversity, for example, by switching to have the wireless station 2-2 perform wireless communication with the communication satellite 3.

[0023] The site diversity in the wireless communication system 1 is triggered by the deterioration of actual communication quality after rainfall, and switches wireless stations when the communication quality falls below a predetermined threshold, for example. Therefore, depending on the rainfall conditions, the wireless communication system 1 may experience a communication interruption before switching wireless stations.

[0024] Therefore, a wireless communication system according to one embodiment is configured to improve availability by predicting rainfall using weather information observed by, for example, multiple wireless stations each equipped with a weather radar, predicting deterioration in communication quality, and switching wireless stations before wireless communication is interrupted.

[0025] Fig. 1 is a diagram showing an example of the configuration of a wireless communication system 10 according to an embodiment. As shown in Fig. 1, the wireless communication system 10 includes, for example, a plurality of wireless stations 20-1 to 20-3, a communication satellite 30, and a control station 40, and constitutes an NTN. Note that when there is no need to specify any one of the multiple components, such as the wireless stations 20-1 to 20-3, it will be simply abbreviated as wireless station 20, etc.

[0026] The wireless stations 20 are, for example, earth stations equipped with base station functions and weather radar, and are connected to a mobile network (not shown). The communication satellite 30 is a node station that relays wireless communications between the wireless stations 20 using communication lines. The control station 40 controls each device (including communication stations such as the wireless station 20) that constitutes the wireless communication system 10 using control signals.

[0027] For example, when wireless station 20-1 is communicating wirelessly with wireless station 20-3 via communication satellite 30, if wireless station 20-1 predicts that the quality of the wireless communication will fall below a predetermined threshold (such as a required C / N) using a rainfall forecast based on weather data acquired by wireless station 20-1, wireless communication system 10 switches the path of the wireless communication.

[0028] For example, when the wireless communication system 10 predicts that the quality of wireless communication between the wireless station 20-1 and the communication satellite 30 will deteriorate due to rain (rain attenuation of radio waves) and fall below a predetermined threshold, it switches the wireless communication between the wireless station 20-1 and the communication satellite 30 to the wireless communication between the wireless station 20-2 and the communication satellite 30, whose communication quality is not predicted to deteriorate, before the quality of wireless communication between the wireless station 20-1 and the communication satellite 30 actually deteriorates and falls below the predetermined threshold.

[0029] Next, we will explain a specific configuration example and functions of the wireless station 20. Fig. 2 is a block diagram illustrating an example configuration and functions of the wireless station 20. As shown in Fig. 2, the wireless station 20 has a communication system including, for example, a communication antenna 21, a transceiver 22, a modem 23, and a transmission device 24, and a meteorological observation system including a weather radar antenna 25, a signal processing device 26, and an analysis device 27.

[0030] The wireless station 20 is also connected to a control station 40 via, for example, a mobile network 100 or another network (not shown).

[0031] The communication antenna 21 is a communication antenna for performing wireless communication with the communication satellite 30. The transmitting / receiving device 22 is a device for transmitting and receiving signals to and from the communication satellite 30 via the communication antenna 21.

[0032] The modem 23 is a device that modulates and demodulates signals transmitted and received by the radio station 20 and outputs the signals to the transceiver 22 (and the transmission device 24). The modem 23 also has a function of superimposing a signal (e.g., quality information, which will be described later) output by the analyzer 27 onto a transmission signal to the communication satellite 30 (or the control station 40).

[0033] For example, when the quality of wireless communication predicted by the quality prediction unit 274 described later is below a predetermined threshold, the modem 23 superimposes quality information indicating that the quality of wireless communication is below a predetermined threshold on the control signal transmitted by the wireless station 20 to the communication satellite 30.

[0034] The transmission device 24 is connected to the mobile network 100 and transmits and receives signals to and from the mobile network 100 .

[0035] The weather radar antenna 25 transmits a weather radar signal in the direction of the communication partner (for example, in the direction toward the communication satellite 30), receives the weather radar signal reflected back by the communication satellite 30, rain clouds, and rainfall, and outputs it to the signal processing device 26.

[0036] That is, since the propagation path between the radio station 20 and the communication satellite 30 can be affected by weather, the weather radar antenna 25 is provided in the radio station 20 and receives the weather radar signal transmitted from the radio station 20 to the communication satellite 30 and reflected therefrom.

[0037] The signal processing device 26 includes an extraction unit 260, which performs signal processing on the weather radar signal output by the weather radar antenna 25 and outputs the signal processing results to the analysis device 27. For example, the extraction unit 260 extracts data necessary for rainfall prediction, such as radar reflectivity factor Z (dBZ) and rainfall intensity R (mm / h), from the weather radar signal received by the weather radar antenna 25, and outputs the data to the analysis device 27.

[0038] The analysis device 27 has, for example, a memory unit 270, a rainfall prediction unit 272, and a quality prediction unit 274, and analyzes the data output by the signal processing device 26 using parameters such as frequency, and outputs the analysis results (processing results) such as quality information described below to the modem 23.

[0039] For example, the storage unit 270 stores and accumulates data extracted by the extraction unit 260 and information indicating the quality of wireless communication predicted by the quality prediction unit 274 (described later).

[0040] The rainfall prediction unit 272 predicts the amount of rainfall between the wireless station 20 and the communication satellite 30 based on the weather radar signal received by the weather radar antenna 25, and outputs information indicating the predicted amount of rainfall to the quality prediction unit 274. More specifically, the rainfall prediction unit 272 predicts the future amount of rainfall between the wireless station 20 and the communication satellite 30 based on the data stored in the storage unit 270, for example, by a short-term rainfall prediction method using 20 minutes of data.

[0041] The quality prediction unit 274 predicts the quality (deterioration, rain attenuation, etc.) of wireless communication between the wireless station 20 and the communication satellite 30 based on parameters such as the amount of rainfall and frequency predicted by the rainfall prediction unit 272, and outputs information (quality information) indicating the predicted quality of wireless communication to, for example, the memory unit 270 (and the modem 23).

[0042] The quality information may include C / N and information indicating whether the quality of wireless communication is below a predetermined threshold.

[0043] Then, the analysis device 27 outputs the quality information stored in the storage unit 270 to the modem 23 in response to an access from the modem 23, for example.

[0044] Next, we will explain specific functions of the control station 40. Fig. 3 is a block diagram illustrating functions of the control station 40. As shown in Fig. 3, the control station 40 includes, for example, a transmitter / receiver 41, a decision unit 42, and a switching control unit 43.

[0045] The transmitter / receiver 41 transmits and receives control signals and the like to and from the radio station 20 and the communication satellite 30 via radio communication or the like.

[0046] The determination unit 42 determines the switching destination of the wireless station 20 based on the control signal received by the transceiver unit 41 (for example, the control signal on which the quality information transmitted by the wireless station 20 is superimposed). For example, when there is a wireless station 20 whose quality of wireless communication with the communication satellite 30 is below a predetermined threshold, the determination unit 42 determines the wireless station 20 whose quality of wireless communication with the communication satellite 30 is equal to or higher than the predetermined threshold as the switching destination of the line, and outputs the determination result to the switching control unit 43.

[0047] When the quality of wireless communication predicted by the quality prediction unit 274 of the wireless station 20 is below a predetermined threshold, the switching control unit 43 performs control via the transceiver unit 41 to switch the line connecting the communication satellite 30 and the wireless station 20 to another line connecting the communication satellite 30 and another communication station (e.g., another wireless station 20) before the line is disconnected.

[0048] For example, the control station 40 controls the switching control unit 43 to switch the line when the transceiver unit 41 receives quality information superimposed by the modem 23 of the wireless station 20. Specifically, the control station 40 transmits control signals to both the wireless station 20 whose wireless communication quality is below a threshold and the wireless station 20 whose wireless communication quality is equal to or above the threshold.

[0049] Then, before the line between the radio station 20 and the communication satellite 30 whose wireless communication quality is below the threshold is cut off, the control station 40 controls to switch the line to the line between the radio station 20 and the communication satellite 30 whose wireless communication quality is above the threshold.

[0050] Next, an operation example of the wireless communication system 10 will be described. Fig. 4 is a flowchart showing an operation example of the wireless communication system 10 according to an embodiment. As shown in Fig. 4, in the wireless communication system 10, the wireless station 20 transmits a weather radar signal from the weather radar antenna 25 (S100), and the weather radar antenna 25 receives the weather radar signal reflected by rain clouds or rainfall and returning (S102).

[0051] The signal processing device 26 performs signal processing on the weather radar signal received by the weather radar antenna 25, and outputs, for example, data necessary for rainfall prediction extracted by the extraction unit 260 to the analysis device 27 (S104).

[0052] The analysis device 27 analyzes the data output by the signal processing device 26 (S106). Specifically, based on the amount of rainfall predicted by the rainfall prediction unit 272, the quality prediction unit 274 predicts the quality (deterioration, etc.) of the wireless communication between the wireless station 20 and the communication satellite 30. For example, the information (quality information) indicating the quality of the wireless communication predicted by the quality prediction unit 274 includes information indicating whether the quality of the wireless communication is below a predetermined threshold.

[0053] Then, the analysis device 27 determines whether the wireless communication between the wireless station 20 and the communication satellite 30 falls below a predetermined quality threshold based on the quality information predicted by the quality prediction unit 274 (S108). If the analysis device 27 determines that the wireless communication between the wireless station 20 and the communication satellite 30 falls below the predetermined quality threshold (S108: Yes), the analysis device 27 proceeds to processing of S110, and if the analysis device 27 determines that the wireless communication does not fall below the predetermined quality threshold (S108: No), the analysis device 27 returns to processing of S100.

[0054] In step 110 (S110), the radio station 20 superimposes quality information indicating that the quality of the wireless communication is below a predetermined threshold on the transmission signal using the modem 23, and transmits the transmission signal with the superimposed quality information to the control station 40 via the communication satellite 30 (or directly).

[0055] In other words, the wireless station 20 performs rainfall prediction based on the weather radar signal received by the weather radar antenna 25, and if it predicts that the quality of wireless communication will fall below a predetermined threshold, it superimposes quality information on a control signal and transmits it to the control station 40.

[0056] In step 112 (S112), the control station 40 switches the wireless station 20. Specifically, before a line between a wireless station 20 whose wireless communication quality is below a threshold and the communication satellite 30 is disconnected, the control station 40 controls to switch the line to a line between a wireless station 20 whose wireless communication quality is equal to or higher than the threshold and the communication satellite 30.

[0057] In this way, when the quality of wireless communication predicted by the quality prediction unit 274 is below a predetermined threshold, the wireless communication system 10 switches the line connecting the communication satellite 30 and the wireless station 20 to another line connecting the communication satellite 30 and another communication station (e.g., another wireless station 20) before the line is cut off, thereby making it possible to prevent wireless communication from being cut off due to weather effects.

[0058] In the above-described embodiment, the wireless communication system 10 is described as having a communication satellite 3 that serves as a node station. However, the wireless communication system 10 may also be a fixed micro wireless system that has a node station other than the communication satellite 3, for example, that is located on the ground and whose propagation path may be affected by weather.

[0059] The wireless communication system 10 may also include one or more wireless stations 20 and one or more other wireless stations 20 or communication stations that perform wired communication. In the wireless communication system 10, one or more wireless stations 20 may also include all of the functions of the control station 40.

[0060] Note that each function possessed by the radio station 20 and the control station 40 may be partially or entirely configured by hardware such as a PLD (Programmable Logic Device) or an FPGA (Field Programmable Gate Array), or may be configured as a program executed by a processor such as a CPU.

[0061] For example, the wireless station 20 and the control station 40 can be realized using a computer and a program, respectively, and the program can be recorded on a storage medium or provided via a network.

[0062] Fig. 5 is a diagram illustrating an example of a hardware configuration of a wireless station 20 according to an embodiment. As illustrated in Fig. 5, the wireless station 20 has an input unit 50, an output unit 51, a communication unit 52, a CPU 53, a memory 54, and an HDD 55 connected via a bus 56, and functions as a computer. The wireless station 20 is also configured to input and output data to and from a computer-readable storage medium 57.

[0063] The input unit 50 is, for example, a keyboard and a mouse. The output unit 51 is, for example, a display device. The input unit 50 and the output unit 51 may be configured as a touch panel or the like.

[0064] The communication unit 52 is a communication interface that performs wireless communication.

[0065] The CPU 53 controls each component of the wireless station 20 and performs predetermined processing, etc. The memory 54 and HDD 55 store data, etc.

[0066] The storage medium 57 is capable of storing programs and the like that cause the wireless station 20 to execute the functions of the wireless station 20. The architecture configuring the wireless station 20 is not limited to the example shown in Fig. 5. Furthermore, the control station 40 may be provided with the same hardware as the wireless station 20. [Explanation of symbols]

[0067] 1,10... Wireless communication system, 2-1 to 2-3, 20-1 to 20-3... Radio station, 21... Communication antenna, 22... Transmitter / receiver device, 23... Modem, 24... Transmission device, 25... Weather radar antenna, 26... Signal processing device, 27... Analytical device, 3,30... Communication satellite, 40... Control station, 41... Transmitter / receiver unit, 42... Decision unit, 43... Switching control unit, 50... Input unit, 51... Output unit, 52... Communication unit, 53... CPU, 54... Memory, 55... HDD, 56... Bus, 57... Storage medium, 100... Mobile network, 260... Extraction unit, 270... Storage unit, 272... Rainfall prediction unit, 274... Quality prediction unit

Claims

1. In a wireless communication system having a wireless station whose propagation path between the wireless station and a node station that relays wireless communication may be affected by weather, a weather radar antenna provided in the wireless station for receiving a weather radar signal transmitted from the wireless station to the node station and reflected therefrom; a rainfall prediction unit that predicts the amount of rainfall between the wireless station and the node station based on the weather radar signal received by the weather radar antenna; a quality prediction unit that predicts the quality of wireless communication between the wireless station and the node station based on the amount of rainfall predicted by the rainfall prediction unit; a switching control unit that performs control to switch the line connecting the node station and the wireless station to another line connecting the node station and another communication station before the line is cut off when the quality of wireless communication predicted by the quality prediction unit is lower than a predetermined threshold; A wireless communication system comprising:

2. an extracting unit that extracts data necessary for rainfall prediction from the weather radar signal received by the weather radar antenna; a storage unit for storing the data extracted by the extraction unit; and The rainfall prediction unit Predicting the amount of rainfall between the wireless station and the node station based on the data stored in the storage unit.

2. The wireless communication system according to claim 1, wherein:

3. A control station that controls the radio station and the communication station and The radio station a modem that, when the quality of wireless communication predicted by the quality prediction unit is below a predetermined threshold, superimposes quality information, indicating that the quality of wireless communication is below a predetermined threshold, on a control signal that the wireless station transmits to the node station; The control station When the modem receives the superimposed quality information, the switching control unit controls to switch the line.

3. The wireless communication system according to claim 1, wherein:

4. A wireless communication method performed by a wireless communication system having a wireless station in which a propagation path between the wireless station and a node station that relays wireless communication may be affected by weather, comprising: a rainfall prediction step of predicting the amount of rainfall between the wireless station and the node station based on a weather radar signal received by a weather radar antenna provided in the wireless station and configured to receive a weather radar signal that has been transmitted from the wireless station toward the node station and reflected therefrom; a quality prediction step of predicting the quality of wireless communication between the wireless station and the node station based on the predicted rainfall amount; a switching control step of performing control to switch the line connecting the node station and the wireless station to another line connecting the node station and another communication station before the line is cut off when the predicted quality of wireless communication is lower than a predetermined threshold; A wireless communication method comprising:

5. an extraction step of extracting data necessary for rainfall prediction from the weather radar signal received by the weather radar antenna; a storage step in which the extracted data is stored in a storage unit; further comprising In the rainfall prediction step, Predicting the amount of rainfall between the wireless station and the node station based on the data stored in the storage unit.

5. The wireless communication method according to claim 4, wherein:

6. In a wireless station in which a propagation path between the wireless station and a node station that relays wireless communications may be affected by weather, a weather radar antenna for transmitting a weather radar signal toward the node station and receiving the reflected weather radar signal; a rainfall prediction unit that predicts the amount of rainfall between the wireless station and the node station based on the weather radar signal received by the weather radar antenna; a quality prediction unit that predicts the quality of wireless communication between the wireless station and the node station based on the amount of rainfall predicted by the rainfall prediction unit; a modem that, when the quality of wireless communication predicted by the quality prediction unit is below a predetermined threshold, superimposes quality information indicating that the quality of wireless communication is below a predetermined threshold on a control signal transmitted from the wireless station to the node station; A radio station comprising:

7. an extracting unit that extracts data necessary for rainfall prediction from the weather radar signal received by the weather radar antenna; a storage unit for storing the data extracted by the extraction unit; and The rainfall prediction unit Predicting the amount of rainfall between the wireless station and the node station based on the data stored in the storage unit.

7. The radio station according to claim 6,

8. a switching control unit that controls switching of the line connecting the node station and the wireless station to another line connecting the node station and another communication station before the line is cut off when the quality of wireless communication predicted by the quality prediction unit is below a predetermined threshold value; 8. The radio station according to claim 6, further comprising:

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