Wireless communication system, terminal, wireless communication method, and wireless communication program

Abstract

According to one embodiment, a wireless communication system includes a terminal, a relay device, and one or more reception devices, the terminal including a communication unit that performs wireless communication with at least the relay device, an acquisition unit that acquires a reception time, a reception strength, and position information stored at a storage unit of each of the reception devices with respect to a beacon signal transmitted by the relay device, an estimation unit that, on the basis of the reception times, reception strengths, and position information acquired by the acquisition unit, estimates the timing at which the relay device will transmit a beacon signal and a data signal next, and a control unit that performs control such that the communication unit begins transmission / reception of a data signal with the relay device at the timing estimated by the estimation unit.

Description

Wireless communication system, terminal, wireless communication method, and wireless communication program

[0001] The present invention relates to a wireless communication system, a terminal, a wireless communication method, and a wireless communication program.

[0002] To build a mobile network, technologies that use geostationary satellites (GEO: geostationary orbit), low earth orbit satellites (LEO: low earth orbit), high altitude platform stations (HAPS: high altitude pseudo satellites), airplanes, drones, etc. are known (see, for example, Non-Patent Document 1).

[0003] Low Earth orbit (LEO), which is an orbit around the Earth at an altitude of 2,000 km or less, is a communication system that has various advantages because it is closer to the Earth's surface than geostationary orbit (GEO).

[0004] Wei Feng, et al. "UAV-aided MIMO communications for 5G Internet of Things", IEEE Internet of Things Journal, VOL. 6, NO. 2, APRIL 2019, p.1731-1740

[0005] However, the time during which a low-earth orbit satellite and a terrestrial terminal (terminal) can communicate is affected by the orbital information of the low-earth orbit satellite and the surrounding environment. Therefore, in the past, in order for a terminal to perform wireless communication at a specific time, the terminal had to acquire orbital information of the low-earth orbit satellite and perform calculations, or the terminal had to receive an external activation signal.

[0006] Furthermore, in order to establish communication with low-earth orbit satellites, the terminal may consume a lot of power in its arithmetic circuits and receiving circuits, leading to an increase in size and cost.

[0007] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a wireless communication system, terminal, wireless communication method, and wireless communication program that enable efficient establishment of communication with a relay device that transmits beacon signals and data signals at highly periodic and reproducible timing while moving.

[0008] A wireless communication system according to one embodiment of the present invention is a wireless communication system having a terminal, a relay device, and one or more receiving devices, in which the relay device transmits beacon signals and data signals at highly periodic and reproducible timing while moving, and each of the receiving devices has a receiving unit that receives the beacon signal transmitted by the relay device, a position detection unit that detects position information indicating the position where the receiving unit received the beacon signal, and a memory unit that stores the reception time and reception strength of the beacon signal received by the receiving unit and the position information detected by the position detection unit, and the terminal has a communication unit that performs wireless communication with at least the relay device, an acquisition unit that acquires the reception time, reception strength, and position information stored in the memory unit for the beacon signal transmitted by the relay device, an estimation unit that estimates the timing when the relay device will next transmit a beacon signal and a data signal based on the reception time, reception strength, and position information acquired by the acquisition unit, and a control unit that controls the communication unit to start transmitting and receiving a data signal to and from the relay device at the timing estimated by the estimation unit.

[0009] In addition, a terminal according to one embodiment of the present invention is a terminal that performs wireless communication with a relay device that transmits beacon signals and data signals at highly periodic and reproducible timing while moving, and is characterized by having: a communication unit that performs wireless communication with at least the relay device; an acquisition unit that acquires, from one or more other devices, location information indicating the reception time, reception strength, and reception location for the beacon signal transmitted by the relay device; an estimation unit that estimates the timing at which the relay device will next transmit a beacon signal and a data signal based on the reception time, reception strength, and location information acquired by the acquisition unit; and a control unit that controls the communication unit to start transmitting and receiving data signals with the relay device at the timing estimated by the estimation unit.

[0010] In addition, a wireless communication method according to one embodiment of the present invention is a wireless communication method in which a terminal communicates wirelessly with a relay device that transmits beacon signals and data signals at highly periodic and reproducible timing while moving, and is characterized by including an acquisition step of acquiring, from one or more other devices, location information indicating the reception time, reception strength, and reception position for the beacon signal transmitted by the relay device; an estimation step of estimating the timing at which the relay device will next transmit a beacon signal and a data signal based on the reception time, reception strength, and location information acquired by the acquisition step; and a control step of controlling the relay device to start transmitting and receiving a data signal at the timing estimated by the estimation step.

[0011] In addition, a wireless communication program according to one embodiment of the present invention is a wireless communication program executed by a terminal that performs wireless communication with a relay device that transmits beacon signals and data signals at highly periodic and reproducible timing while moving, and causes a computer to function as each part of the terminal having at least a communication unit that performs wireless communication with the relay device, an acquisition unit that acquires from one or more other devices location information indicating the reception time, reception strength, and reception location for the beacon signal transmitted by the relay device, an estimation unit that estimates the timing when the relay device will next transmit a beacon signal and a data signal based on the reception time, reception strength, and location information acquired by the acquisition unit, and a control unit that controls the communication unit to start transmitting and receiving data signals with the relay device at the timing estimated by the estimation unit.

[0012] According to the present invention, it is possible to efficiently establish communication with a relay device that transmits beacon signals and data signals at highly periodic and repeatable timings while moving.

[0013] FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system according to an embodiment. FIG. 2 is a functional block diagram illustrating an example of the configuration of a receiving device. FIG. 3 is a functional block diagram illustrating an example of the configuration of a terminal according to an embodiment. FIG. 4 is a diagram illustrating a first operation example of a wireless communication system according to an embodiment. FIG. 5 is a diagram illustrating an example of reception time, reception strength, and location information stored in a receiving device. FIG. 6 is a diagram illustrating a second operation example of a wireless communication system according to an embodiment. FIG. 7 is a diagram schematically illustrating a process performed by a terminal according to an embodiment when estimating reception strength at the location of the terminal. FIG. 8 is a diagram schematically illustrating a result of estimating the transmission and reception timing of a data signal based on the reception time and field strength estimated by a terminal according to an embodiment. FIG. 9 is a diagram illustrating an example of the hardware configuration of a terminal according to an embodiment.

[0014] A wireless communication system according to an embodiment will be described below with reference to the drawings. Fig. 1 is a diagram showing an example of the configuration of a wireless communication system 1 according to an embodiment. As shown in Fig. 1, in the wireless communication system 1 according to an embodiment, communication is relayed to a terminal (terrestrial terminal) 3 that performs wireless communication with a base station 2 by at least one of a HAPS 4, a low-earth orbit satellite (sun-synchronous orbit, sun-synchronous quasi-recurrent orbit, etc.) 5, and a geostationary satellite 6. The wireless communication system 1 also includes, for example, three receiving devices 7 that receive beacon signals transmitted by the low-earth orbit satellites 5.

[0015] In other words, the HAPS 4, the low-earth orbit satellite 5, and the geostationary satellite 6 function as relay devices. The low-earth orbit satellite 5 also functions as a relay device that transmits beacon signals and data signals at highly periodic and repeatable timing while moving.

[0016] Furthermore, the receiving device 7 may be, for example, a dedicated terminal for receiving beacon signals transmitted by low-orbit satellites 5, a smartphone, or a smartphone with a receiving device connected thereto, and may be standalone (not connected to a network) when receiving beacon signals.

[0017] 2 is a functional block diagram showing an example of the configuration of the receiving device 7. As shown in FIG. 2, the receiving device 7 includes a communication unit 71, a position detection unit 72, a storage unit 73, and a control unit 74.

[0018] The communication unit 71 has a receiving unit 710 and a transmitting unit 712. The receiving unit 710 receives, for example, a beacon signal transmitted by a low-earth orbit satellite 5. The transmitting unit 712 transmits a signal to the low-earth orbit satellite 5.

[0019] The position detection unit 72 detects, for example, using GPS, position information (latitude, longitude, ellipsoid height, etc.) indicating the position where the receiving unit 710 received the beacon signal.

[0020] The storage unit 73 stores the reception time and reception strength (received electric field strength) of the beacon signal received by the receiver 710 , and the position information detected by the position detector 72 .

[0021] The control unit 74 controls each unit constituting the receiving device 7. The receiving device 7 may be configured to transmit the reception time, reception strength, and location information stored in the storage unit 73 to a shared server (not shown) or the like.

[0022] 3 is a functional block diagram illustrating an example configuration of a terminal 3 according to an embodiment. As illustrated in FIG. 3, the terminal 3 includes, for example, a communication unit 31, an acquisition unit 32, an estimation unit 33, and a control unit 34. The terminal 3 also includes at least one communication function corresponding to, for example, IMT-Advanced, Bluetooth (registered trademark), Wi-Fi (registered trademark), IoT (Internet of Things), and the like.

[0023] The communication unit 31 includes a receiving unit 310 and a transmitting unit 312, and performs wireless communication with the low-earth orbit satellite 5 and the receiving device 7. For example, the receiving unit 310 receives a beacon signal transmitted by the low-earth orbit satellite 5. The transmitting unit 312 transmits a signal to the low-earth orbit satellite 5, for example.

[0024] The acquisition unit 32 acquires, via the communication unit 31 , the reception time, reception strength, and location information stored in the storage unit 73 of the receiving device 7 for the beacon signal transmitted by the low-earth orbit satellite 5 .

[0025] The estimation unit 33 estimates the timing when the low-earth orbit satellite 5 will next transmit a beacon signal and a data signal based on the reception time, reception strength, and position information acquired by the acquisition unit 32.

[0026] The control unit 34 controls each unit constituting the terminal 3. For example, the control unit 34 controls the communication unit 31 to start transmitting and receiving data signals to and from the low-earth orbit satellite 5 at the timing estimated by the estimation unit 33.

[0027] Furthermore, when the control unit 34 controls the communication unit 31 to start transmitting and receiving data signals to and from the low-earth orbit satellite 5, the control unit 34 may also control the acquisition unit 32 to acquire new reception time, reception strength, and location information after a predetermined period has elapsed. In other words, the control unit 34 can make corrections to the orbit of the low-earth orbit satellite 5 after a predetermined period has elapsed.

[0028] Next, an operation example of the wireless communication system 1 will be described with reference to Figures 4 to 8. Figure 4 is a diagram showing a first operation example of the wireless communication system 1 according to an embodiment. As shown in Figure 4, first, the low-earth orbit satellite 5 transmits a beacon signal or the like to the receiving device 7 (S100).

[0029] The receiving device 7 receives a beacon signal or the like from a low-earth orbit satellite 5 (S200). Then, the receiving device 7 detects location information indicating the location where the beacon signal or the like is received, for example, using a GPS or the like (S202).

[0030] The receiving device 7 then stores the reception time, reception strength, and location information within its own device (S204), and also stores the reception time, reception strength, and location information in, for example, a shared server (not shown) (S300). Figure 5 is a diagram illustrating an example of the reception time, reception strength (received field strength), and location information stored by the receiving device 7 (or the shared server (not shown)).

[0031] 6 is a diagram illustrating a second operation example of the wireless communication system 1 according to an embodiment. As illustrated in FIG. 6, the receiving device 7 (or a shared server not shown) stores the reception time, reception strength, and location information (S400).

[0032] The terminal 3 acquires the reception time, reception strength, and location information stored in the receiving device 7 (or a shared server, not shown) by communication or by reading it in advance (S500). The terminal 3 also detects location information indicating the location of the terminal 3 using, for example, GPS or the like (S502).

[0033] Then, the terminal 3 estimates (calculates) the timing of transmitting and receiving the data signal based on the acquired reception time, reception strength, and location information (S504). At this time, the terminal 3 estimates the reception strength at its own location based on the reception strength (field strength) and location information (longitude, latitude, etc.) detected by, for example, three receiving devices 7 at different locations, using a certain time as a reference.

[0034] 7 is a diagram schematically illustrating a process performed by a terminal 3 according to an embodiment when estimating the reception strength at its own location. As shown in FIG. 7 , for example, when three receiving devices 7 receive beacon signals at positions A, B, and C, respectively, and acquire the reception strength, the terminal 3 estimates the reception time and reception strength at its own location, X. Note that when there is only one receiving device 7 or when multiple receiving devices 7 are in the same location, the terminal 3 uses the reception strength stored in the receiving device 7.

[0035] 8 is a diagram illustrating an example of an estimation result of the transmission and reception timing of a data signal based on the reception time and field strength estimated by the terminal 3 according to an embodiment. By estimating the transmission and reception timing of the data signal, the terminal 3 can obtain a timing that is likely to result in successful communication with the low-earth orbit satellite 5 (selection of communication parameters that have a high success rate).

[0036] Then, the terminal 3 starts transmitting and receiving data to and from the low earth orbit satellite 5 at the estimated timing (S506). At this time, the low earth orbit satellite 5 starts transmitting and receiving data to and from the terminal 3 (S600).

[0037] In this way, the wireless communication system 1 has an acquisition unit 32 that acquires the reception time, reception strength, and location information stored in the memory unit 73 of the receiving device 7 for a beacon signal transmitted by a low-orbit satellite 5, and estimates the timing when the low-orbit satellite 5 will next transmit a beacon signal and a data signal based on the acquired reception time, reception strength, and location information.Therefore, it is possible to efficiently establish communication with a low-orbit satellite (relay device) 5 that transmits beacon signals and data signals at highly periodic and reproducible timings while moving.

[0038] In other words, the terminal 3 can use the reception time, reception strength, and location information stored in the receiving device 7 to determine the transmission and reception timing from the location and time of the terminal itself, and can communicate with the low-orbit satellite 5 efficiently, resulting in a configuration that is smaller than conventional devices and also reduces power consumption.

[0039] In addition, each function possessed by terminal 3 may be configured in part or in whole by hardware such as a PLD (Programmable Logic Device) or FPGA (Field Programmable Gate Array), or may be configured as a program executed by a processor such as a CPU.

[0040] For example, the terminal 3 can be realized using a computer and a program, and the program can be recorded on a storage medium or provided via a network.

[0041] 9 is a diagram illustrating an example of the hardware configuration of a terminal 3 according to an embodiment. As illustrated in FIG. 9, the terminal 3 has an input unit 90, an output unit 91, a communication unit 92, a CPU 93, a memory 94, and an HDD 95 connected via a bus 96, and functions as a computer. The terminal 3 is also capable of inputting and outputting data to and from a computer-readable storage medium 97.

[0042] The input unit 90 is, for example, a keyboard and a mouse, etc. The output unit 91 is, for example, a display device such as a display.

[0043] The communication unit 92 is, for example, a communication interface that performs wireless communication.

[0044] The CPU 93 controls each component of the terminal 3 and performs predetermined processing, etc. The memory 94 and HDD 95 store data, etc.

[0045] The storage medium 97 is capable of storing programs and the like that cause the terminal 3 to execute the functions of the terminal 3. The architecture that configures the terminal 3 is not limited to the example shown in FIG.

[0046] 1...wireless communication system, 2...base station, 3...terminal, 4...HAPS, 5...low-orbit satellite (relay device), 6...geostationary satellite, 7...receiving device, 31...communication unit, 32...acquisition unit, 33...estimation unit, 34...control unit, 71...communication unit, 72...position detection unit, 73...storage unit, 74...control unit, 90...input unit, 91...output unit, 92...communication unit, 93...CPU, 94...memory, 95...HDD, 96...bus, 97...storage medium, 310...receiving unit, 312...transmitting unit, 710...receiving unit, 712...transmitting unit

Claims

1. A wireless communication system having a terminal, a relay device, and one or more receiving devices, wherein the relay device transmits beacon signals and data signals with highly periodic and reproducible timing while moving, and each of the receiving devices has a receiving unit that receives the beacon signal transmitted by the relay device, a position detection unit that detects position information indicating the position where the receiving unit received the beacon signal, and a memory unit that stores the reception time and reception strength of the beacon signal received by the receiving unit and the position information detected by the position detection unit, and the terminal has at least a communication unit that performs wireless communication with the relay device, an acquisition unit that acquires the reception time, reception strength, and position information stored in the memory unit for the beacon signal transmitted by the relay device, an estimation unit that estimates the timing when the relay device will next transmit a beacon signal and a data signal based on the reception time, reception strength, and position information acquired by the acquisition unit, and a control unit that controls the communication unit to start transmitting and receiving a data signal to and from the relay device at the timing estimated by the estimation unit.

2. The wireless communication system according to claim 1, wherein the control unit controls the communication unit to start transmitting and receiving data signals with the relay device, and then controls the acquisition unit to acquire new reception time, reception strength and location information after a predetermined period of time has elapsed.

3. The wireless communication system according to claim 1 or 2, wherein the relay device is a low-earth orbit satellite.

4. A terminal that wirelessly communicates with a relay device that transmits beacon signals and data signals with high periodicity and reproducibility while moving, the terminal having: a communication unit that wirelessly communicates with at least the relay device; an acquisition unit that acquires from one or more other devices location information indicating the reception time, reception strength, and reception location for the beacon signal transmitted by the relay device; an estimation unit that estimates the timing when the relay device will next transmit a beacon signal and a data signal based on the reception time, reception strength, and location information acquired by the acquisition unit; and a control unit that controls the communication unit to start transmitting and receiving data signals with the relay device at the timing estimated by the estimation unit.

5. The terminal according to claim 4, wherein the control unit controls the communication unit to start transmitting and receiving data signals with the relay device, and then controls the acquisition unit to acquire new reception time, reception strength and location information after a predetermined period of time has elapsed.

6. A wireless communication method in which a terminal communicates wirelessly with a relay device that transmits beacon signals and data signals with highly periodic and reproducible timing while moving, the method comprising: an acquisition step of acquiring, from one or more other devices, location information indicating the reception time, reception strength, and reception location for the beacon signal transmitted by the relay device; an estimation step of estimating the timing for the relay device to next transmit a beacon signal and a data signal based on the reception time, reception strength, and location information acquired by the acquisition step; and a control step of controlling the relay device to start transmitting and receiving a data signal at the timing estimated by the estimation step.

7. The wireless communication method according to claim 6, wherein in the control step, when control is performed to start transmission and reception of a data signal with the relay device, after a predetermined period of time has elapsed, control is performed so that new reception time, reception strength and location information is acquired by the acquisition step.

8. A wireless communication program executed by a terminal that wirelessly communicates with a relay device that transmits beacon signals and data signals with highly periodic and reproducible timing while moving, the wireless communication program causing a computer to function as each part of the terminal having at least a communication unit that wirelessly communicates with the relay device, an acquisition unit that acquires from one or more other devices location information indicating the reception time, reception strength, and reception position for the beacon signal transmitted by the relay device, an estimation unit that estimates the timing when the relay device will next transmit a beacon signal and a data signal based on the reception time, reception strength, and location information acquired by the acquisition unit, and a control unit that controls the communication unit to start transmitting and receiving data signals with the relay device at the timing estimated by the estimation unit.

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