Radio communication device, radio communication method, radio communication program, and ground station

Abstract

To reduce the effects of deterioration of communication quality of radio communication between a satellite and a ground station.SOLUTION: When a radio communication device mounted on a satellite detects a deterioration in the communication quality of a first radio communication with a ground station, the radio communication device performs narrowband control to narrow the bandwidth of a frequency band used for the first radio communication to the ground station. When transmission data to be sent to the ground station cannot be sent within a specified time through the first radio communication, the radio communication device performs control to transmit transfer data, which is at least a portion of the transmission data, to another satellite via a second radio communication with another radio communication device mounted on another satellite.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a wireless communication device, a wireless communication method, a wireless communication program, and a ground station.

Background Art

[0002] When performing wireless communication between a satellite (hereinafter referred to as a satellite in this application) and a ground station, the communication quality of the wireless communication may deteriorate due to the influence of obstacles existing between the satellite and the ground station. For example, rain and clouds can also be obstacles. When a high-frequency band is used for wireless communication, the directivity of radio waves becomes stronger, so it is more susceptible to the influence of obstacles.

[0003] On the other hand, for example, in the method described in Patent Document 1, when the communication quality of a high-frequency band satellite communication line deteriorates due to rainfall or the like, the ground station cuts off the transmission of data to the high-frequency band satellite communication line and communicates only via the low-frequency band satellite communication line. Thereby, an important communication line is secured.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the method described in Patent Document 1, there is a possibility that the bandwidth is insufficient for the amount of data to be transmitted.

[0006] An object of the present disclosure is to provide a wireless communication device, a wireless communication method, a wireless communication program, and a ground station that can reduce the influence of deterioration in the communication quality of wireless communication between a satellite and a ground station in view of the above-described problems.

Means for Solving the Problems

[0007] In one aspect of the present disclosure, a wireless communication device is a wireless communication device mounted on a satellite, and includes a first communication unit that performs first wireless communication with a ground station, a second communication unit that performs second wireless communication with another wireless communication device mounted on another satellite, and a control unit that controls the first wireless communication and the second wireless communication. When the control unit detects a deterioration in the communication quality of the first wireless communication, it performs narrowbanding control to narrow the bandwidth of the frequency band used for the first wireless communication with the ground station. When transmission data to be transmitted to the ground station cannot be transmitted within a predetermined time by the first wireless communication, it controls to transmit transfer data, which is at least a part of the transmission data, to another satellite via the second wireless communication.

[0008] Also, in another aspect of the present disclosure, a wireless communication method is a wireless communication method of a wireless communication device mounted on a satellite. When a deterioration in the communication quality of first wireless communication with a ground station is detected, narrowbanding control is performed to narrow the bandwidth of the frequency band used for the first wireless communication with the ground station. When transmission data to be transmitted to the ground station cannot be transmitted within a predetermined time by the first wireless communication, control is performed to transmit transfer data, which is at least a part of the transmission data, to another satellite via second wireless communication with another wireless communication device mounted on another satellite.

[0009] In another aspect of the present disclosure, the wireless communication program is a wireless communication program for a wireless communication device mounted on a satellite, which causes a computer to realize a first communication function for performing first wireless communication with a ground station, a second communication function for performing second wireless communication with another wireless communication device mounted on another satellite, and a control function for controlling the first wireless communication and the second wireless communication. When the control function detects a deterioration in the communication quality of the first wireless communication, it performs narrowbanding control to narrow the bandwidth of the frequency band used for the first wireless communication to the ground station. When transmission data to be transmitted to the ground station cannot be transmitted within a predetermined time by the first wireless communication, it controls to transmit transfer data, which is at least a part of the transmission data, to another satellite via the second wireless communication.

[0010] In another aspect of the present disclosure, the ground station includes a communication unit that performs wireless communication with a wireless communication device mounted on a satellite, and a control unit that controls the wireless communication of the wireless communication device. When the control unit detects a deterioration in the communication quality of the wireless communication, it performs narrowbanding control to narrow the bandwidth of the frequency band used for the wireless communication from the wireless communication device to the ground station. When the wireless communication device cannot transmit within a predetermined time by the wireless communication the transmission data to be transmitted from the wireless communication device to the ground station, it controls the wireless communication device to transmit transfer data, which is at least a part of the transmission data, to another satellite.

[0011] In another aspect of the present disclosure, the method of the ground station, when detecting a deterioration in the communication quality of the wireless communication between the ground station and a wireless communication device mounted on a satellite, performs narrowbanding control to narrow the bandwidth of the frequency band used for the wireless communication from the wireless communication device to the ground station. When the wireless communication device cannot transmit within a predetermined time by the wireless communication the transmission data to be transmitted from the wireless communication device to the ground station, it controls the wireless communication device to transmit transfer data, which is at least a part of the transmission data, to another satellite.

[0012] In another aspect of the present disclosure, the program of the terrestrial station causes a computer to implement a communication function for performing wireless communication with a wireless communication device mounted on a satellite and a control function for controlling the wireless communication of the wireless communication device. When the control function detects a deterioration in the communication quality of the wireless communication, the control function performs narrowbanding control to narrow the bandwidth of the frequency band used for the wireless communication from the wireless communication device to the terrestrial station. When the wireless communication device cannot transmit all the transmission data to the terrestrial station within a predetermined time in the wireless communication, the control function controls the wireless communication device to transmit transfer data, which is at least a part of the transmission data, to another satellite.

Effect of the Invention

[0013] According to the present disclosure, it is possible to reduce the influence of deterioration in the communication quality of wireless communication between a satellite and a terrestrial station.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Mode for Carrying Out the Invention

[0015] [First Embodiment] The first embodiment of the present disclosure will be described.

[0016] Note that a specific example of the wireless communication device 10 in the first embodiment is the wireless communication device 20 in the second embodiment described later.

[0017] First, a configuration example of the wireless communication device 10 will be described. FIG. 1 shows a configuration example of the wireless communication device 10. The wireless communication device 10 includes a first communication unit 11, a second communication unit 12, and a control unit 13. The wireless communication device 10 is mounted on a satellite.

[0018] The first communication unit 11 performs first wireless communication with the terrestrial station. The second communication unit 12 performs second wireless communication with other wireless communication devices mounted on other satellites. The control unit 13 controls the first wireless communication and the second wireless communication. When the control unit 13 detects a deterioration in the communication quality of the first wireless communication, it performs narrowbanding control. The narrowbanding control is control to narrow the bandwidth of the frequency band used for the first wireless communication to the terrestrial station.

[0019] In addition, when the control unit 13 cannot transmit all the transmission data to the terrestrial station within a predetermined time by the first wireless communication, it controls to transmit the transfer data to other satellites via the second wireless communication. The transfer data is at least a part of the transmission data.

[0020] Next, an example of the operation flow of the wireless communication device 10 will be described. FIG. 2 shows an example of the operation flow of the wireless communication device 10.

[0021] When the control unit 13 detects a deterioration in the communication quality of the first wireless communication, it performs narrowbanding control (step S101). The narrowbanding control is control to narrow the bandwidth of the frequency band used for the first wireless communication with the ground station.

[0022] Further, when the control unit 13 cannot transmit all the transmission data to be transmitted to the ground station within a predetermined time by the first wireless communication, it performs control to transmit the transfer data to another satellite via the second wireless communication (step S102). The transfer data is at least a part of the transmission data.

[0023] As described above, in the first embodiment of the present disclosure, the wireless communication device 10 includes a first communication unit 11, a second communication unit 12, and a control unit 13. The wireless communication device 10 is mounted on a satellite. The first communication unit 11 performs first wireless communication with the ground station. The second communication unit 12 performs second wireless communication with another wireless communication device mounted on another satellite. The control unit 13 controls the first wireless communication and the second wireless communication. When the control unit 13 detects a deterioration in the communication quality of the first wireless communication, it performs narrowbanding control. The narrowbanding control is control to narrow the bandwidth of the frequency band used for the first wireless communication with the ground station. Further, when the control unit 13 cannot transmit all the transmission data to be transmitted to the ground station within a predetermined time by the first wireless communication, it performs control to transmit the transfer data to another satellite via the second wireless communication. The transfer data is at least a part of the transmission data.

[0024] Thereby, the wireless communication device 10 improves the communication quality of the first wireless communication by narrowbanding control. Further, the wireless communication device 10 transmits data that cannot be transmitted by the first wireless communication to another satellite. Thereby, the transferred data transmitted to another satellite can be sent to the ground station or another ground station via the other satellite. Therefore, it is possible to reduce the influence of the deterioration of the communication quality of the wireless communication between the satellite and the ground station.

[0025] [Second Embodiment] Next, the wireless communication device 20 in the second embodiment of the present disclosure will be described. Note that a specific example of the wireless communication device 10 in the first embodiment is the wireless communication device 20 in the second embodiment.

[0026] First, FIG. 3 shows an example of a wireless communication system 72 including the wireless communication device 20.

[0027] The wireless communication system 72 includes satellites 30-i (i is an integer from 1 to N, and N is an integer of 2 or more) and terrestrial stations 40-i. When it is not necessary to distinguish each of the satellites 30-1 to 30-N, each of the satellites 30-1 to 30-N may be referred to as a satellite 30. Also, when it is not necessary to distinguish each of the terrestrial stations 40-1 to 40-N, each of the terrestrial stations 40-1 to 40-N may be referred to as a terrestrial station 40.

[0028] In the example shown in FIG. 3, for simplicity of explanation, the number of satellites 30 and the number of terrestrial stations 40 are the same, but the number of satellites 30 and the number of terrestrial stations 40 may be different. Also, the correspondence between the satellites 30 and the terrestrial stations 40 that can communicate wirelessly with each other may be fixed or variable. If the satellite 30 is a geostationary satellite, this correspondence is fixed, and if the satellite 30 is a low-earth orbit satellite, this correspondence changes with time. Also, between one terrestrial station 40, a plurality of two or more satellites 30 may perform wireless communication. Also, one satellite 30 may be capable of communicating with a plurality of two or more terrestrial stations 40.

[0029] The terrestrial stations 40-1 to 40-N can communicate with each other via a communication line 80.

[0030] The wireless communication device 20 is mounted on the satellite 30-1. The satellites 30-2 to 30-N may also be mounted with wireless communication devices similar to the wireless communication device 20.

[0031] The wireless communication device 20 performs wireless communication with the terrestrial station 40-1. The terrestrial station 40 that performs wireless communication with the wireless communication device 20 may be fixed or variable as described above.

[0032] In addition, the wireless communication device 20 performs wireless communication with other satellites. The wireless communication device 20 can perform wireless communication with satellites in the vicinity of the satellite 30-1 on which the wireless communication device 20 is mounted. The satellites that can perform wireless communication with the wireless communication device 20 may be fixed or variable. If the satellite 30 is a geostationary satellite, the neighboring satellites are fixed, and if the satellite 30 is a orbiting satellite, the neighboring satellites change with time. In the state shown in FIG. 3, the neighboring satellites of the satellite 30-1 are the satellites 30-2 and 30-N, and the wireless communication device 20 can communicate with the satellites 30-2 and 30-N. Similarly, the other satellites 30-2 to 30-N can perform wireless communication with their neighboring satellites.

[0033] Next, FIG. 4 shows a configuration example of the wireless communication device 20. The wireless communication device 20 includes a first communication unit 21, a second communication unit 22, and a control unit 23.

[0034] The first communication unit 21 performs first wireless communication with any one of the ground stations 40-1 to 40-N. Hereinafter, it is assumed that the first communication unit 21 performs first wireless communication with the ground station 40-1.

[0035] When the satellite 30-1 is an orbiting satellite, the ground stations that can communicate with the satellite 30-1 change with time. When the satellite 30-1 can be positioned by GNSS (Global Navigation Satellite System), the position of the satellite 30-1 can be grasped by positioning using GNSS. Since the satellite 30-1 grasps the position information of the ground stations 40-1 to 40-N, the ground stations that can communicate with the satellite 30-1 can be grasped. The ground stations that can communicate with the satellite 30-1 are the ground stations existing within a predetermined distance from the satellite 30-1. Alternatively, the satellite 30-1 may grasp the ground stations that can communicate with the satellite 30-1 at a predetermined time from the position information of the ground stations 40-1 to 40-N and the orbit information of the satellite 30-1.

[0036] The second communication unit 22 performs second wireless communication with other wireless communication devices mounted on other satellites. The second communication unit 22 performs second wireless communication with satellites in the vicinity of satellite 30-1. Hereinafter, it is assumed that the second communication unit 22 performs second wireless communication with satellites 30-2 and 30-N.

[0037] In the case where satellite 30-1 is a orbiting satellite, the satellites in the vicinity of satellite 30-1 change with time. Since satellite 30-1 grasps the orbital information of satellites 30-1 to 30-N, it is possible to grasp the satellites in the vicinity of satellite 30-1 at a predetermined time.

[0038] The control unit 23 controls the first wireless communication and the second wireless communication.

[0039] When the control unit 23 detects a deterioration in the communication quality of the first wireless communication, it performs narrowbanding control. The narrowbanding control is control to narrow the bandwidth of the frequency band used for the first wireless communication to the ground station 40-1.

[0040] In this narrowbanding control, the control unit 23 narrows the bandwidth of the frequency band used for the first wireless communication without changing the transmission power of the first wireless communication. As a result, the SNR (signal-to-noise ratio) of the first wireless communication can be improved. As a result, the communication quality of the first wireless communication can be improved.

[0041] The narrowbanding control may be, for example, control to change the modulation method of the first wireless communication. For example, when 32QAM (Quadrature Amplitude Modulation) is used for the first wireless communication, the control unit 23 can halve the bandwidth of the first wireless communication by changing the modulation method of the first wireless communication to 16QAM.

[0042] Also, the narrowbanding control may be, for example, control to change the data rate of the first wireless communication. The narrowbanding control may be control to change the modulation method and data rate of the first wireless communication. For example, the control unit 23 can halve the bandwidth of the first wireless communication by reducing the data rate of the first wireless communication by half.

[0043] For example, the control unit 23 may perform narrowbanding control by setting the bandwidth of the first wireless communication to a bandwidth obtained by multiplying the used bandwidth by a power of one-half.

[0044] Also, the control unit 23 may determine to what extent to narrow the bandwidth according to the cause and degree of deterioration of the communication quality. In this case, it is assumed that the relationship between the cause of deterioration and the bandwidth, and the relationship between the degree of deterioration and the bandwidth are determined in advance.

[0045] Also, when the control unit 23 detects the elimination of the deterioration of the communication quality of the first wireless communication, the control unit 23 may perform control to cancel the narrowbanding control, that is, control to restore the bandwidth of the frequency band used for the first wireless communication to its original value.

[0046] Note that in the narrowbanding control for the first wireless communication, the control unit 23 may not change the center frequency of the used band, or may change it due to other factors (such as interference).

[0047] Also, in detecting the deterioration of the communication quality of the first wireless communication, the control unit 23 may measure the communication quality and detect the deterioration of the measured communication quality, or may detect an event in which the communication quality may deteriorate.

[0048] For example, the control unit 23 may detect a deterioration in the communication quality of the first wireless communication based on weather information. Also, the weather information may be weather information included in an AIS (Automatic Identification System) signal. When an AIS signal is used, the wireless communication device 20 may include an AIS signal receiving unit 54 as in the wireless communication device 50 shown in FIG. 5. FIG. 5 is a diagram showing a configuration example of the wireless communication device 50. The AIS signal receiving unit 54 receives an AIS signal. The wireless communication device 20 may receive weather information via satellites (30-2, 30-N) near the ground station 40-1.

[0049] The AIS signal is mainly used to inform the position of a ship, but is also used to inform a ship of weather information etc. from an AIS signal transmitting device existing on a lighthouse or the like. The control unit 23 can use, for example, the weather information included in the AIS signal for estimating the communication quality of the first wireless communication.

[0050] The storage means (not shown) inside or outside the wireless communication device 20 may store, for example, in advance a correspondence table with the identification information (for example, MSSI (Maritime Mobile Service Identity) Number) of the nearest AIS signal transmitting device (existing on a lighthouse etc.) of the ground stations 40-1 to 40-N. Then, the control unit 23 can estimate the communication quality of the first wireless communication based on the weather information included in the AIS signal from the nearest AIS signal transmitting device to the ground station 40-1.

[0051] Alternatively, the control unit 23 may determine, based on the position information included in the AIS signal, the AIS signal from the nearest AIS signal transmitting device to the ground station 40-1 among the received AIS signals, and estimate the communication quality of the first wireless communication based on the weather information included in the AIS signal.

[0052] The control unit 23 may estimate the communication quality of the first wireless communication using, for example, "Present Weather" included in the AIS signal. FIG. 6 shows an example of weather information included in the AIS signal. The control unit 23 may estimate that the communication quality has deteriorated, for example, when "Present Weather" has an available value (in the case of the example in FIG. 6, "0" to "7") and is neither "clear" nor "cloudy". When the first wireless communication is by optical communication, the control unit 23 may estimate that the communication quality has deteriorated, for example, when "Present Weather" is not "clear". The control unit 23 may estimate the communication quality using information other than "Present Weather".

[0053] Further, the control unit 23 may estimate the communication quality of the first wireless communication by a method other than the method based on the AIS signal. For example, when the communication quality of the signal from the ground station 40-1 (for example, BER (Bit Error Rate) or SNR) is poor, when clouds are reflected in the image of the direction of the ground station 40-1 taken from the satellite 30-1, or when the weather forecast near the ground station 40-1 is poor, it may be estimated that the communication quality of the first wireless communication is poor or will deteriorate in the future.

[0054] Even if the communication quality of the first wireless communication is improved by narrowbanding control, due to the narrowing of the bandwidth of the first wireless communication, the first communication unit 21 may not be able to transmit all the data intended to be sent to the ground station 40-1 within a predetermined time. Hereinafter, the data intended to be sent to the ground station 40-1 may be referred to as transmission data. Therefore, when the control unit 23 is unable to transmit all the transmission data within a predetermined time using the first wireless communication, the control unit 23 controls to transmit at least a part of the transmission data to another satellite via the second wireless communication. Hereinafter, at least a part of the transmission data that is transmitted to another satellite may be referred to as transfer data. As a result, the transfer data can be sent from another satellite to any one of the ground stations 40-1 to 40-N. Therefore, the wireless communication device 20 can improve the communication quality of the first wireless communication by narrowbanding control, and by transmitting the transfer data to another satellite, it can send more transmission data to the ground than when narrowbanding control is not performed.

[0055] When performing narrowbanding control, the control unit 23 determines whether transmission to another satellite is necessary. As described above, when the control unit 23 is unable to transmit all the transmission data within a predetermined time using the first wireless communication, it determines that transmission to another satellite is necessary. Then, when the control unit 23 determines that transmission to another satellite is necessary, the control unit 23 controls to transmit at least a part of the transmission data to another satellite via the second wireless communication.

[0056] The transmission data is the data intended to be sent from the wireless communication device 20 to the ground station 40-1. The transmission data may include, for example, data generated at the satellite 30-1. The data generated at the satellite 30-1 may include, for example, an image captured by a photographing device mounted on the satellite 30-1. Also, the transmission data may include data received from another satellite. Also, the transmission data may include data obtained by making some changes to the data received from another satellite. Also, the transmission data may include transfer data generated at another satellite.

[0057] The control unit 23 determines that transmission to another satellite is necessary, for example, in the following cases.

[0058] The control unit 23 calculates, for example, the required time, which is the time required for transmitting the transmission data, based on the amount of data that can be transmitted per unit time (data rate after narrowbanding control) at the bandwidth after narrowbanding control and the amount of data of the transmission data. Then, the control unit 23 determines that transmission to another satellite is necessary when the calculated required time exceeds the transmission available time of the transmission data. The transmission available time is the time from the transmission start time of the transmission data to the time when transmission should be completed.

[0059] For example, when satellite 30-1 is an orbiting satellite, there is an upper limit to the time during which communication with one ground station can be maintained. Therefore, when the wireless communication device 20 can communicate with a certain ground station, for example, it starts transmitting the transmission data to the ground station. In this case, the transmission available time is the time from the start of transmission of the transmission data until communication with the ground station can be maintained.

[0060] The transmission available time is not limited to this example and may be determined by other criteria. For example, in the case of transmission data that is periodically transmitted, the transmission available time may be the transmission period of the transmission data.

[0061] Further, the control unit 23 may determine that transmission to another satellite is necessary, for example, when the amount of data that can be transmitted per unit time (data rate after narrowbanding control) at the bandwidth after narrowbanding control is lower than the amount of transmission data (required data rate) that is desired to be transmitted per unit time.

[0062] When the control unit 23 determines that transmission to other satellites is necessary, it controls to transmit at least a part of the transmission data to other satellites via the second wireless communication. The transfer data transmitted to other satellites is, for example, the data obtained by excluding the data that can be transmitted within a predetermined time by the first wireless communication from the transmission data. Any method can be used to determine which data among the transmission data is to be the transfer data. For example, when the bandwidth of the first wireless communication is halved, the control unit 23 may use more than half of the transmission data as the transfer data.

[0063] The control unit 23 transmits the transfer data to satellites that can perform inter-satellite communication by the second wireless communication. The satellites that can perform inter-satellite communication by the second wireless communication are satellites in the vicinity of satellite 30-1. If satellite 30-1 is a geostationary satellite, since the neighboring satellites are fixed, the control unit 23 transmits the transfer data to the predetermined neighboring satellites. When satellite 30-1 is a low-earth orbit satellite, the control unit 23 can grasp the neighboring satellites at a certain point in time based on the orbit information of satellites 30-2 to 30-N. In the example shown in FIG. 3, satellite 30-1 can perform inter-satellite communication between satellite 30-2 and satellite 30-N.

[0064] The transfer data transmitted to other satellites may be further sent to other satellites by a wireless communication device mounted on another satellite, which is similar to the wireless communication device 20.

[0065] The control unit 23 may determine a ground station that receives the transfer data transmitted from satellite 30-1 to other satellites. The ground station that receives the transfer data may hereinafter be referred to as the downlink destination ground station.

[0066] The control unit 23 may, for example, determine a ground station with good estimated communication quality as the downlink destination ground station. The control unit 23 may, for example, receive information on the communication quality between the satellite and each of ground stations 40-1 to 40-N via inter-satellite communication (via the second communication unit 22), and determine the downlink destination ground station based on the received information.

[0067] Further, the control unit 23 may determine the downlink destination terrestrial station based on, for example, the AIS signal. As described above, the AIS signal includes position information and weather information. The control unit 23 can estimate the communication quality around the terrestrial stations 40-1 to 40-N based on the position information and weather information included in the AIS signal.

[0068] The control unit 23 may use the AIS signal received by the AIS signal receiving unit 54. The AIS signal receiving unit 54 can receive AIS signals from a range up to about 2500 km from the AIS signal receiving unit 54. The wireless communication device 20 may receive information on AIS signals received by other satellites via the second communication unit 22.

[0069] For example, the control unit 23 may estimate a terrestrial station with good communication quality between the satellite using "Present Weather" included in the AIS signal. In this case, for example, if there is an AIS signal with "Present Weather" being "clear" or "cloudy" among the AIS signals transmitted from a position close to (within a predetermined distance) the terrestrial stations 40-1 to 40-N, the control unit 23 may use the terrestrial station close to the transmission position of this AIS signal as the downlink destination terrestrial station. When there are an AIS signal with "Present Weather" being "clear" and an AIS signal with "Present Weather" being "cloudy", the control unit 23 may preferentially use the terrestrial station close to the transmission position of the AIS signal with "Present Weather" being "clear" as the downlink destination terrestrial station. When there are multiple candidate terrestrial stations for the downlink destination terrestrial station, the control unit 23 may use the terrestrial station closest to the satellite 30-1 among the candidate terrestrial stations for the downlink destination terrestrial station as the downlink destination terrestrial station.

[0070] By using the AIS signal, the control unit 23 can autonomously determine the downlink destination terrestrial station on the satellite side.

[0071] Further, the control unit 23 may determine the satellite that finally transmits the transfer data transmitted from the satellite 30-1 to another satellite to any one of the ground stations 40-1 to 40-N. In this case, the satellite that finally transmits the transfer data to the ground station may hereinafter be referred to as the downlink satellite. The control unit 23 may, for example, first determine the downlink destination ground station and then determine the satellite that can communicate with the downlink destination ground station as the downlink satellite. When the satellite is a circular satellite, the control unit 23 may determine the downlink satellite in consideration of the time required for transferring the transfer data. For example, the control unit 23 may determine as the downlink satellite the satellite that is expected to have the shortest time from receiving the transfer data until it can communicate with the downlink destination ground station.

[0072] When the control unit 23 determines the downlink destination ground station, for example, it controls the second communication unit 22 to transmit the transfer data with the information of the downlink destination ground station added to a neighboring satellite. When there are two or more neighboring satellites (satellites that can communicate with the satellite 30-1), the satellite to which the transfer data is to be transmitted may be, for example, the satellite on the path with the fewest number of satellites through which the transfer data passes until the downlink destination ground station.

[0073] In addition, when the control unit 23 receives the transfer data generated by another satellite, it determines whether to further transfer the transfer data to another satellite or transmit it to the ground station based on the information of the downlink destination ground station attached to the transfer data. The transfer data generated by another satellite may sometimes be distinguished from the transfer data generated by the satellite 30-1 and referred to as other-satellite transfer data. If the satellite 30-1 is a geostationary satellite, when the downlink destination ground station is the ground station 40-1, the control unit 23 causes the first communication unit 21 to transmit the other-satellite transfer data to the ground station 40-1.

[0074] If the satellite 30-1 is a circular satellite, when the ground station that can communicate with the satellite 30-1 next is the downlink destination ground station, the control unit 23 causes the first communication unit 21 to transmit the other-satellite transfer data to the downlink destination ground station.

[0075] When the control unit 23 determines a downlink satellite, for example, it controls the second communication unit 22 to transmit transfer data with information of the downlink satellite to neighboring satellites. When there are two or more neighboring satellites (satellites capable of communicating with satellite 30-1), the satellite to which the transfer data is to be transmitted may be, for example, a satellite on the path with the smallest number of satellites through which the transfer data passes before reaching the downlink satellite.

[0076] Also, when the control unit 23 receives other-satellite transfer data from other satellites, it determines whether to further transfer the other-satellite transfer data to other satellites or transmit it to the ground station based on the information of the downlink satellite given to the other-satellite transfer data. When satellite 30-1 is the downlink satellite, the control unit 23 causes the first communication unit 21 to transmit the other-satellite transfer data to the ground station 40-1.

[0077] Next, an example of the operation flow of the wireless communication device 20 will be described with reference to FIGS. 7 and 8.

[0078] When the control unit 23 detects deterioration in the communication quality of the first wireless communication (YES in step S201 of FIG. 7), it performs narrowbanding control (step S202). When deterioration in the communication quality of the first wireless communication has not been detected, the transmission data is transmitted by the first communication unit 21 in the first wireless communication without narrowbanding to the ground station 40-1.

[0079] Also, when the control unit 23 cannot finish transmitting the transmission data within a predetermined time in the first wireless communication (NO in step S203), it controls to transmit the transfer data to other satellites via the second wireless communication (step S204).

[0080] In step S204 of FIG. 7, the control unit 23 may determine the downlink destination ground station or the downlink satellite.

[0081] Further, when the control unit 23 detects the elimination of the deterioration of the communication quality of the first wireless communication (YES in step S205), it performs control to cancel the bandwidth narrowing (step S206). Further, the control unit 23 may perform control to cancel the transmission of the transfer data to other satellites (step S207). Note that the control unit 23 may transmit the transfer data determined to be transferred to other satellites as it is to other satellites via the second wireless communication.

[0082] Also, when information on the downlink destination ground station or the downlink satellite is added to the transfer data to other satellites, the wireless communication device 20 may operate as in the operation flow example of FIG. 8.

[0083] When the second communication unit 22 receives the transfer data to other satellites (step S301 in FIG. 8), the control unit 23 determines whether to transmit the transfer data to other satellites to the ground station 40-1. The control unit 23 makes this determination based on the information on the downlink destination ground station or the downlink satellite added to the transfer data to other satellites.

[0084] Then, when the control unit 23 determines to transmit the transfer data to other satellites to the ground station 40-1 (YES in step S302), it transmits the transfer data to other satellites to the ground station 40-1 by the first wireless communication (step S303). Also, when the control unit 23 determines not to transmit the transfer data to other satellites to the ground station 40-1 (NO in step S302), it transmits the transfer data to other satellites (step S304). Here, the control unit 23 transmits the transfer data to other satellites to a satellite different from the satellite that transmitted the transfer data to other satellites. For example, in FIG. 3, when the wireless communication device 20 receives the transfer data to other satellites from the satellite 30-N, the wireless communication device 20 transmits the transfer data to other satellites to the satellite 30-2.

[0085] As described above, in the second embodiment of the present disclosure, the wireless communication device 20 includes a first communication unit 21, a second communication unit 22, and a control unit 23. The wireless communication device 20 is mounted on a satellite. The first communication unit 21 performs first wireless communication with the ground station 40-1. The second communication unit 22 performs second wireless communication with other wireless communication devices mounted on other satellites. The control unit 23 controls the first wireless communication and the second wireless communication. When the control unit 23 detects a deterioration in the communication quality of the first wireless communication, it performs bandwidth reduction control. The bandwidth reduction control is control to narrow the bandwidth of the frequency band used for the first wireless communication to the ground station 40-1. Further, when the control unit 23 cannot transmit all the transmission data to the ground station 40-1 within a predetermined time by the first wireless communication, it controls to transmit the transfer data to another satellite via the second wireless communication. The transfer data is at least a part of the transmission data.

[0086] Thereby, the wireless communication device 20 improves the communication quality of the first wireless communication by the bandwidth reduction control. Further, the wireless communication device 20 transmits the data that cannot be transmitted by the first wireless communication to another satellite. Thereby, the transfer data transmitted to another satellite can be sent to the ground station 40-1 or another ground station via another satellite. Therefore, it is possible to reduce the influence of the deterioration of the communication quality of the wireless communication between the satellite and the ground station.

[0087] Further, the transfer data may be transmitted to the ground station 40-1 or any one of the other ground stations 40-1 to 40-N by another wireless communication device mounted on any one of the other satellites 30-1 to 30-N. Thereby, it is possible to reduce the amount of data that cannot be sent from the wireless communication device 20 to the ground.

[0088] Further, the control unit 23 may detect a deterioration in the communication quality of the first wireless communication based on the weather information included in the AIS signal. Thereby, it is possible to easily detect the deterioration of the communication quality of the first wireless communication.

[0089] Further, the wireless communication device may further include an AIS signal receiving unit 54 that receives an AIS signal. Thereby, the wireless communication device 20 mounted on the satellite 30-1 can autonomously realize control.

[0090] Also, the control unit 23 may determine the downlink destination terrestrial station. The downlink destination terrestrial station is a terrestrial station that receives the transfer data. Further, the control unit 23 may determine the downlink destination terrestrial station based on the communication quality of the communication between the other wireless communication device and the other terrestrial stations 40-2 to 40-N that communicate with the other wireless communication device. Also, the control unit 23 may determine the downlink satellite. The downlink satellite is a satellite that transmits the transfer data to the terrestrial station 40-1 or the other terrestrial stations 40-2 to 40-N. Thereby, transmission of the transfer data to the terrestrial stations 40-1 to 40-N can be realized.

[0091] Also, the control unit 23 may perform control to transmit the transfer data with the information of the downlink destination terrestrial station to another satellite via the second wireless communication. Also, the control unit 23 may perform control to transmit the transfer data with the information of the downlink satellite to another satellite via the second wireless communication. Also, when the other satellite transfer data is received via the second wireless communication, the control unit 23 may determine whether to further transfer the other satellite transfer data to another satellite or transmit it to the terrestrial station based on the information of the downlink destination terrestrial station given to the other satellite transfer data. Also, when the other satellite transfer data is received via the second wireless communication, the control unit 23 may determine whether to further transfer the other satellite transfer data to another satellite or transmit it to the terrestrial station based on the information of the downlink satellite given to the other satellite transfer data. Thereby, the other satellites 30-2 to 30-N that have received the transfer data can easily determine whether to further transfer the transfer data to another satellite.

[0092] Further, the control unit 23 may estimate the communication quality of communication between another wireless communication device and other ground stations 40-2 to 40-N that communicate with the other wireless communication device based on the weather information included in the AIS signal. As a result, the wireless communication device 20 mounted on the satellite 30-1 can autonomously determine the downlink destination ground station and the downlink satellite.

[0093] Further, the narrowbanding control may be at least one of control for changing the modulation scheme of the first wireless communication and control for changing the data rate of the first wireless communication. Thereby, narrowbanding control can be realized and the SNR of the first wireless communication can be improved.

[0094] [Third Embodiment] Next, a third embodiment of the present disclosure will be described. In the present embodiment, the ground station 41-1 performs the control that the control unit 23 of the wireless communication device 20 performed in the second embodiment.

[0095] First, FIG. 9 shows an example of the wireless communication system 73 of the present disclosure.

[0096] The wireless communication system 73 includes satellites 31-i (i is an integer from 1 to N, N is an integer of 2 or more) and ground stations 41-i. When it is not necessary to distinguish each of the satellites 31-1 to 31-N, each of the satellites 31-1 to 31-N may be referred to as satellite 31. Also, when it is not necessary to distinguish each of the ground stations 41-1 to 41-N, each of the ground stations 41-1 to 41-N may be referred to as ground station 41.

[0097] Note that the description of the wireless communication system 73 is the same as that obtained by replacing the satellite 30 of the wireless communication system 72 with the satellite 31, the ground station 40 with 41, and the wireless communication device 20 with the wireless communication device 60, and thus will be omitted.

[0098] Next, FIG. 10 shows a configuration example of the wireless communication device 60. The wireless communication device 60 includes a first communication unit 61, a second communication unit 62, and a control unit 63. The wireless communication device 60 may further include an AIS signal receiving unit 64 as in the wireless communication device 65 shown in FIG. 11.

[0099] The first communication unit 61 performs first wireless communication with any one of the terrestrial stations 41-1 to 41-N. Hereinafter, it is assumed that the first communication unit 61 performs first wireless communication with the terrestrial station 41-1.

[0100] The second communication unit 62 performs second wireless communication with other wireless communication devices mounted on other satellites. The second communication unit 62 performs second wireless communication with satellites in the vicinity of the satellite 31-1. Hereinafter, it is assumed that the second communication unit 62 performs second wireless communication with the satellites 31-2 and 31-N.

[0101] The control unit 63 controls the first wireless communication and the second wireless communication according to an instruction from the terrestrial station 41-1.

[0102] The AIS signal receiving unit 64 receives an AIS signal. Information on the AIS signal received by the AIS signal receiving unit 64 may be transmitted to the terrestrial station 41-1 by the first wireless communication and to neighboring satellites by the second wireless communication.

[0103] Next, FIG. 12 shows a configuration example of the terrestrial station 41-i. The terrestrial station 41-i includes a communication unit 42-i and a control unit 43-i. Hereinafter, the terrestrial station 41-1 will be described.

[0104] The communication unit 42-1 performs wireless communication (first wireless communication) with the wireless communication device 60 mounted on the satellite 31-1.

[0105] The control unit 43-1 controls the wireless communication (first wireless communication) between the terrestrial station 41-1 and the wireless communication device 60 mounted on the satellite 31-1, and the wireless communication (second wireless communication) between the satellite 31-1 and other satellites.

[0106] When the control unit 43-1 detects a deterioration in the communication quality of the wireless communication (first wireless communication) with the satellite 31-1, it performs bandwidth narrowing control to narrow the bandwidth of the frequency band used for the wireless communication from the satellite 31-1 to the ground station 41-1. Since the method of the bandwidth narrowing control is the same as that of the second embodiment, the description thereof is omitted.

[0107] Further, when the control unit 43-1 detects the elimination of the deterioration in the communication quality of the wireless communication with the satellite 31-1, it may perform control to cancel the bandwidth narrowing control, that is, control to restore the bandwidth of the frequency band used for the wireless communication with the satellite 31-1.

[0108] Further, when detecting the deterioration in the communication quality of the wireless communication with the satellite 31-1, the control unit 43-1 may measure the communication quality and detect the measured deterioration in the communication quality, or may detect an event in which the communication quality may deteriorate.

[0109] For example, the control unit 43-1 may receive the information of the AIS signal from the satellite 31-1 and use the information of the AIS signal for estimating the communication quality. Further, the control unit 43-1 may receive the information of the AIS signal received by at least any one of the satellites 31-1 to 31-N via at least any one of the other ground stations 41-2 to 40-N, and use the information of the AIS signal for estimating the communication quality.

[0110] Further, the control unit 43-1 may estimate the communication quality of the wireless communication with the satellite 31-1 by a method other than the method based on the AIS signal. For example, when the communication quality (e.g., BER or SNR) of the signal from the satellite 31-1 is poor, when there are clouds over the ground station 41-1, or when the weather forecast in the vicinity of the ground station 41-1 is poor, it may be estimated that the communication quality of the wireless communication with the satellite 31-1 is poor or will deteriorate in the future.

[0111] Further, when the transmission data to be transmitted from the wireless communication device 60 mounted on the satellite 31-1 to the ground station 41-1 cannot be completely transmitted by the wireless communication device 60 within a predetermined time in wireless communication, the control unit 43-1 controls the wireless communication device 60 to transmit transfer data, which is at least a part of the transmission data, to another satellite.

[0112] As a result, the transfer data of the satellite 31-1 can be sent from another satellite to any one of the ground stations 41-2 to 41-N. Therefore, the communication quality of the wireless communication from the satellite 31-1 to the ground station 41-1 is improved by the narrowbanding control. Also, when the transfer data of the satellite 31-1 is transmitted to another satellite, more transmission data is sent from the satellite 31-1 to the ground than when the narrowbanding control is not performed.

[0113] When performing the narrowbanding control, the control unit 43-1 may determine whether transmission to another satellite from the satellite 31-1 is necessary. Also, this determination may be made by the control unit 63 of the wireless communication device 60 mounted on the satellite 31-1.

[0114] When the wireless communication device 60 cannot completely transmit the transmission data within a predetermined time in wireless communication, the control unit 43-1 may determine that transmission to another satellite is necessary. In this case, the control unit 43-1 may receive information on the amount of transmission data from the wireless communication device 60. Then, when the control unit 23 determines that transmission to another satellite is necessary, the control unit 23 controls the wireless communication device 60 to transmit at least a part of the transmission data to another satellite via the second wireless communication.

[0115] The control unit 43-1 may determine the downlink destination ground station or the downlink satellite. When the control unit 43-1 determines the downlink destination ground station or the downlink satellite, the result of the determination is transmitted to the wireless communication device 60 of the satellite 31-1. The method for determining the downlink destination ground station or the downlink satellite is the same as that in the second embodiment.

[0116] Next, an example of the operation flow of the ground station 41-1 will be described with reference to FIG. 7.

[0117] When the control unit 43-1 detects a deterioration in the communication quality of the wireless communication (first wireless communication) between the ground station 41-1 and the satellite 31-1 (YES in step S201 of FIG. 7), it performs narrowbanding control (step S202). The instruction for narrowbanding may be given to the wireless communication device 60 of the satellite 31-1 via other ground stations 41-2 to 41-N and other satellites 31-2 to 31-N. Also, when the deterioration in the communication quality of the wireless communication has not been detected, the transmission data is transmitted to the ground station 41-1 by the first communication unit 61 in the first wireless communication that has not been narrowbanded.

[0118] Also, when the wireless communication device 60 cannot transmit all the transmission data within a predetermined time in the first wireless communication (NO in step S203), the control unit 43-1 controls the wireless communication device 60 to transmit the transfer data to another satellite via the second wireless communication (step S204).

[0119] In step S204 of FIG. 7, the control unit 43-1 may determine the downlink destination ground station or the downlink satellite.

[0120] Also, when the control unit 43-1 detects the elimination of the deterioration in the communication quality of the first wireless communication (YES in step S205), it performs control to cancel the narrowbanding (step S206). Also, the control unit 43-1 may perform control to cancel the transmission of the transfer data from the wireless communication device 60 to another satellite (step S207).

[0121] As described above, in the third embodiment of the present disclosure, the ground station 41-1 includes a communication unit 42-1 and a control unit 43-1. The communication unit 42-1 performs wireless communication with the wireless communication device 60 mounted on the satellite. The control unit 43-1 controls the wireless communication of the wireless communication device 60. When the control unit 43-1 detects a deterioration in the communication quality of the wireless communication, it performs narrowbanding control to narrow the bandwidth of the frequency band used for the wireless communication from the wireless communication device 60 to the ground station 41-1. Further, when the wireless communication device 60 cannot transmit all the transmission data to the ground station 41-1 within a predetermined time in the wireless communication, the control unit 43-1 controls the wireless communication device 60 to transmit the transfer data to another satellite. The transfer data is at least a part of the transmission data.

[0122] Thereby, the ground station 41-1 improves the communication quality of the wireless communication from the wireless communication device 60 to the ground station 41-1 by the narrowbanding control. Further, the ground station 41-1 causes the wireless communication device 60 to transmit the data that the wireless communication device 60 cannot transmit in the wireless communication to another satellite. Thereby, the transfer data transmitted to another satellite can be sent to the ground station 41-1 or another ground station via another satellite. Therefore, it is possible to reduce the influence of the deterioration in the communication quality of the wireless communication between the satellite and the ground station.

[0123] [Hardware Configuration Example] A configuration example of the hardware resources for realizing the wireless communication devices (10, 20, 50, 60, 65) and the ground stations (40-i, 41-i) (hereinafter, wireless communication devices, etc.) in each of the above-described embodiments of the present disclosure using a single information processing device (computer) will be described. Note that the wireless communication devices, etc. may be realized using at least two information processing devices physically or functionally. Further, the wireless communication devices, etc. may be realized as dedicated devices. Further, only some of the functions of the wireless communication devices, etc. may be realized using an information processing device.

[0124] FIG. 13 is a diagram schematically showing a hardware configuration example of an information processing apparatus capable of realizing a wireless communication apparatus and the like according to each embodiment of the present disclosure. The information processing apparatus 90 includes a communication interface 91, an input / output interface 92, an arithmetic unit 93, a storage device 94, a nonvolatile storage device 95, and a drive device 96.

[0125] For example, the first communication unit 11 and the second communication unit 12 in FIG. 1 can be realized by the communication interface 91. Also, the control unit 13 can be realized by the arithmetic unit 93.

[0126] The communication interface 91 is a communication means for a wireless communication apparatus and the like according to each embodiment to communicate with an external apparatus by wire and / or wirelessly. When realizing a wireless communication apparatus and the like using at least two information processing apparatuses, they may be connected so as to be able to communicate with each other via the communication interface 91.

[0127] The input / output interface 92 is a man-machine interface such as a keyboard which is an example of an input device and a display as an output device.

[0128] The arithmetic unit 93 is realized by a general-purpose CPU (Central Processing Unit), a microprocessor, or the like, which is an arithmetic processing device, or a plurality of electric circuits. The arithmetic unit 93 can, for example, read various programs stored in the nonvolatile storage device 95 into the storage device 94 and execute processing according to the read programs.

[0129] The storage device 94 is a memory device such as a RAM (Random Access Memory) that can be referenced by the arithmetic unit 93, and stores programs and various data. The storage device 94 may be a volatile memory device.

[0130] The non-volatile memory device 95 is a non-volatile memory device such as, for example, a ROM (Read Only Memory), a flash memory, etc., and can store various programs, data, etc.

[0131] The drive device 96 is a device that processes, for example, reading and writing of data to a recording medium 97 described later.

[0132] The recording medium 97 is an arbitrary recording medium capable of recording data, such as, for example, an optical disk, a magneto-optical disk, a semiconductor flash memory, etc.

[0133] Each embodiment of the present disclosure may be realized, for example, by configuring a wireless communication device or the like with the information processing device 90 illustrated in FIG. 13 and supplying a program capable of realizing the functions described in the above embodiments to the wireless communication device or the like.

[0134] In this case, the embodiment can be realized by the arithmetic unit 93 executing the program supplied to the wireless communication device or the like. Also, it is possible to configure not all but some of the functions of the wireless communication device or the like with the information processing device 90.

[0135] Furthermore, the above program may be recorded on the recording medium 97, and the wireless communication device or the like may be configured such that the above program is appropriately stored in the non-volatile memory device 95 at the time of shipment or operation of the wireless communication device or the like. In this case, as the supply method of the above program, a method of installing it in the wireless communication device or the like using an appropriate jig may be adopted at the manufacturing stage before shipment or at the operation stage or the like. Also, as the supply method of the above program, a general procedure such as a method of downloading from the outside via a communication line such as the Internet may be adopted.

[0136] Some or all of the above embodiments may be described as follows in the appended claims, but are not limited thereto.

[0137] (Appended Claim 1) A wireless communication device mounted on a satellite, a first communication unit that performs first wireless communication with a ground station; a second communication unit that performs second wireless communication with another wireless communication device mounted on another satellite; a control unit that controls the first wireless communication and the second wireless communication; and is provided with wherein the control unit when detecting deterioration in the communication quality of the first wireless communication, performs narrowbanding control to narrow the bandwidth of the frequency band used for the first wireless communication to the ground station; when the transmission data to be transmitted to the ground station cannot be completely transmitted within a predetermined time by the first wireless communication, controls to transmit transfer data, which is at least a part of the transmission data, to another satellite via the second wireless communication; a wireless communication device.

[0138] (Appendix 2) the transfer data is transmitted to the ground station or another ground station by another wireless communication device; the wireless communication device according to Appendix 1.

[0139] (Appendix 3) the control unit detects deterioration in the communication quality of the first wireless communication based on weather information included in the AIS signal; the wireless communication device according to Appendix 1 or Appendix 2.

[0140] (Appendix 4) an AIS signal receiving unit that receives the AIS signal and further includes the wireless communication device according to Appendix 3.

[0141] (Appendix 5) the control unit determines a downlink destination ground station, which is a ground station that receives the transfer data; the wireless communication device according to any one of Appendices 1 to 4.

[0142] (Appendix 6) The control unit determines the downlink destination ground station based on the communication quality of communication between another wireless communication device and another ground station that communicates with the other wireless communication device. The wireless communication device according to Supplementary Note 5.

[0143] (Supplementary Note 7) The control unit estimates the communication quality of communication between another wireless communication device and another ground station that communicates with the other wireless communication device based on the weather information included in the AIS signal. The wireless communication device according to Supplementary Note 6.

[0144] (Supplementary Note 8) The AIS signal receiving unit that receives the AIS signal The wireless communication device according to Supplementary Note 7, further comprising the AIS signal receiving unit.

[0145] (Supplementary Note 9) The control unit performs control to transmit the transfer data to which the information of the downlink destination ground station is given to another satellite via the second wireless communication. The wireless communication device according to any one of Supplementary Notes 5 to 8.

[0146] (Supplementary Note 10) When the control unit receives other satellite transfer data, which is transfer data generated by another satellite, via the second wireless communication, based on the information of the downlink destination ground station given to the other satellite transfer data, the control unit determines whether to further transfer the other satellite transfer data to another satellite or transmit it to the ground station. The wireless communication device according to Supplementary Note 9.

[0147] (Supplementary Note 11) The control unit determines the downlink satellite, which is the satellite that transmits the transfer data to the ground station or another ground station. The wireless communication device according to any one of Supplementary Notes 1 to 4.

[0148] (Supplementary Note 12) The control unit performs control to transmit the transfer data with the information of the downlink satellite to other satellites via the second wireless communication. The wireless communication device according to Supplementary Note 11.

[0149] (Supplementary Note 13) When the control unit receives other satellite transfer data, which is transfer data generated by other satellites, via the second wireless communication, based on the information of the downlink satellite attached to the other satellite transfer data, the control unit determines whether to further transfer the other satellite transfer data to other satellites or transmit it to the ground station. The wireless communication device according to Supplementary Note 12.

[0150] (Supplementary Note 14) The narrowbanding control is at least one of control to change the modulation method of the first wireless communication and control to change the data rate of the first wireless communication. The wireless communication device according to any one of Supplementary Notes 1 to 13.

[0151] (Supplementary Note 15) A wireless communication method of a wireless communication device mounted on a satellite, When detecting deterioration in the communication quality of the first wireless communication with the ground station, perform narrowbanding control to narrow the bandwidth of the frequency band used for the first wireless communication to the ground station, When the transmission data to be transmitted to the ground station cannot be transmitted within a predetermined time by the first wireless communication, perform control to transmit at least a part of the transmission data, which is transfer data, to other satellites via the second wireless communication with other wireless communication devices mounted on other satellites. Wireless communication method.

[0152] (Supplementary Note 16) A wireless communication program of a wireless communication device mounted on a satellite, To a computer, A first communication function for performing the first wireless communication with the ground station, A second communication function for performing second wireless communication with other wireless communication devices mounted on other satellites, a control function for controlling the first wireless communication and the second wireless communication, is realized, the control function is when detecting deterioration of communication quality of the first wireless communication, perform narrowbanding control to narrow the bandwidth of the frequency band used for the first wireless communication to the ground station, when the transmission data to be transmitted to the ground station cannot be transmitted within a predetermined time by the first wireless communication, perform control to transmit transfer data, which is at least part of the transmission data, to other satellites via the second wireless communication, Wireless communication program.

[0153] (Appendix 17) a communication unit for performing wireless communication with a wireless communication device mounted on a satellite, a control unit for controlling the wireless communication of the wireless communication device is provided, the control unit is when detecting deterioration of communication quality of the wireless communication, perform narrowbanding control to narrow the bandwidth of the frequency band used for the wireless communication from the wireless communication device to the ground station, when the wireless communication device cannot transmit within a predetermined time by the wireless communication the transmission data to be transmitted from the wireless communication device to the ground station, control the wireless communication device to transmit transfer data, which is at least part of the transmission data, to other satellites, Ground station.

[0154] (Appendix 18) the transfer data is transmitted to the ground station or other ground stations by other wireless communication devices mounted on other satellites, The ground station according to Appendix 17.

[0155] (Appendix 19) the control unit detects deterioration of communication quality of the wireless communication based on weather information included in the AIS signal, The terrestrial station described in Supplementary Note 17 or Supplementary Note 18.

[0156] (Supplementary Note 20) The control unit determines a downlink destination terrestrial station, which is a terrestrial station that receives the transfer data. The terrestrial station described in any one of Supplementary Notes 17 to 19.

[0157] (Supplementary Note 21) The control unit determines the downlink destination terrestrial station based on the communication quality of the communication between another wireless communication device mounted on another satellite and another terrestrial station that communicates with the other wireless communication device. The terrestrial station described in Supplementary Note 20.

[0158] (Supplementary Note 22) The control unit estimates the communication quality of the communication between another wireless communication device and another terrestrial station that communicates with the other wireless communication device based on the weather information included in the AIS signal. The terrestrial station described in Supplementary Note 21.

[0159] (Supplementary Note 23) The control unit determines a downlink satellite, which is a satellite that transmits the transfer data to the terrestrial station or another terrestrial station. The terrestrial station described in any one of Supplementary Notes 17 to 19.

[0160] (Supplementary Note 24) The narrowbanding control is at least one of control for changing the modulation method of the wireless communication and control for changing the data rate of the wireless communication. The terrestrial station described in any one of Supplementary Notes 17 to 23.

[0161] (Supplementary Note 25) When detecting a deterioration in the communication quality of the wireless communication between the terrestrial station and the wireless communication device mounted on the satellite, narrowbanding control is performed to narrow the bandwidth of the frequency band used for the wireless communication from the wireless communication device to the terrestrial station. When the wireless communication device cannot transmit all the transmission data to the terrestrial station within a predetermined time in the wireless communication, the wireless communication device is controlled to transmit transfer data, which is at least a part of the transmission data, to another satellite. Method of terrestrial station.

[0162] (Appendix 26) In a computer, a communication function for performing wireless communication with a wireless communication device mounted on a satellite, and a control function for controlling the wireless communication of the wireless communication device are realized, and the control function when detecting a deterioration in the communication quality of the wireless communication, performs narrowbanding control to narrow the bandwidth of the frequency band used for the wireless communication from the wireless communication device to the terrestrial station, When the wireless communication device cannot transmit all the transmission data to the terrestrial station within a predetermined time in the wireless communication, the wireless communication device is controlled to transmit transfer data, which is at least a part of the transmission data, to another satellite. Program of terrestrial station.

[0163] Also, part or all of the configurations described in Appendices 2 to 14 that are subordinate to Appendix 1 described above can be subordinate to Appendices 15 and 16 in the same subordinate relationship as Appendices 2 to 14. Furthermore, not limited to Appendices 1, 15, and 16, within the scope not departing from the above-described embodiments, similarly, part or all of the configurations described as appendices can be made subordinate to various hardware, software, various recording means for recording software, or systems.

[0164] In addition, some or all of the configurations described in Appendices 18 to 24 that are subordinate to Appendix 17 described above may be subordinate to Appendices 25 and 26 in the same subordinate relationship as Appendices 18 to 24. Furthermore, not limited to Appendices 17, 25, and 26, within the scope not departing from the above-described embodiments, for various hardware, software, various recording means for recording software, or systems, similarly, some or all of the configurations described as appendices may be made subordinate.

[0165] As described above, the present disclosure has been described with reference to the embodiments. However, the present disclosure is not limited to the above-described embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure. And each embodiment can be combined with other embodiments as appropriate.

Description of Reference Numerals

[0166] 10, 20, 50, 60, 65 Wireless communication device 11, 21, 61 First communication unit 12, 22, 62 Second communication unit 13, 23, 63 Control unit 54, 64 AIS signal receiving unit 30, 30-i, 31, 31-i Satellite 40, 40-i, 41, 41-i Ground station 42-i Communication unit 43-i Control unit 72, 73 Wireless communication system 80 Communication line 90 Information processing device 91 Communication interface 92 Input / output interface 93 Arithmetic unit 94 Storage device 95 Non-volatile storage device 96 Drive device 97 Recording medium

Claims

1. A wireless communication device mounted on a satellite, comprising: a first communication unit that performs first wireless communication with a ground station; a second communication unit that performs second wireless communication with another wireless communication device mounted on another satellite; a control unit that controls the first wireless communication and the second wireless communication; When the control unit detects a deterioration in the communication quality of the first wireless communication, it performs narrowbanding control to narrow the bandwidth of the frequency band used for the first wireless communication to the ground station. When the transmission data to be transmitted to the ground station cannot be transmitted within a predetermined time by the first wireless communication, it controls to transmit transfer data, which is at least a part of the transmission data, to another satellite via the second wireless communication. Wireless communication device.

2. The transfer data is transmitted to the ground station or another ground station by another wireless communication device. The wireless communication device according to claim 1.

3. The control unit detects a deterioration in the communication quality of the first wireless communication based on weather information included in an AIS (Automatic Identification System) signal. The wireless communication device according to claim 1.

4. The control unit determines a downlink destination ground station, which is a ground station that receives the transfer data. The wireless communication device according to claim 1.

5. The control unit determines the downlink destination ground station based on the communication quality of the communication between another wireless communication device and another ground station that communicates with the other wireless communication device. The wireless communication device according to claim 4.

6. The control unit estimates the communication quality of the communication between another wireless communication device and another ground station that communicates with the other wireless communication device based on weather information included in an AIS signal. The wireless communication device according to claim 5.

7. The narrowbanding control is at least one of control to change the modulation method of the first wireless communication and control to change the data rate of the first wireless communication. The wireless communication device according to claim 1.

8. A wireless communication method for a wireless communication device mounted on a satellite, comprising: When detecting a deterioration in the communication quality of the first wireless communication with a ground station, performing narrowbanding control to narrow the bandwidth of the frequency band used for the first wireless communication to the ground station. ​ ​ When the transmission data to be transmitted to the ground station cannot be completely transmitted within a predetermined time by the first wireless communication, control is performed to transmit transfer data, which is at least part of the transmission data, to another satellite via a second wireless communication with another wireless communication device mounted on another satellite. Wireless communication method. **Claim 9** A wireless communication program for a wireless communication device mounted on a satellite, causing a computer to have a first communication function for performing a first wireless communication with a ground station, have a second communication function for performing a second wireless communication with another wireless communication device mounted on another satellite, have a control function for controlling the first wireless communication and the second wireless communication, and realizing wherein the control function performs bandwidth reduction control to narrow the bandwidth of the frequency band used for the first wireless communication to the ground station when deterioration of the communication quality of the first wireless communication is detected, and performs control to transmit transfer data, which is at least part of the transmission data, to another satellite via the second wireless communication when the transmission data to be transmitted to the ground station cannot be completely transmitted within a predetermined time by the first wireless communication. Wireless communication program. **Claim 10** A communication unit that performs wireless communication with a wireless communication device mounted on a satellite, and a control unit that controls the wireless communication of the wireless communication device are provided, wherein the control unit performs bandwidth reduction control to narrow the bandwidth of the frequency band used for the wireless communication from the wireless communication device to the ground station when deterioration of the communication quality of the wireless communication is detected, and controls the wireless communication device to transmit transfer data, which is at least part of the transmission data, to another satellite when the wireless communication device cannot completely transmit the transmission data from the wireless communication device to the ground station within a predetermined time by the wireless communication. Ground station.

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