Network systems and communication methods

Abstract

The network system (1) is configured to include a plurality of communication nodes (3) that wirelessly receive information to be collected and transmit the received information to each other, and a relay station (2) that can simultaneously send and receive information with each communication node (3). Each communication node (3) transmits status information about its own status to the relay station (2), the relay station (2) receives the status information from each communication node (3), and distributes node control information to each communication node (3) which is generated using the received status information and is used to control the operation of each communication node (3), and each communication node (3) receives the node control information from the relay station (2) and is controlled to transmit information to each other based on the received node control information.

Description

Technical Field

[0005]

[0001] The present disclosure relates to a network system and a communication method.

Background Art

[0002] Conventionally, an IoT (Internet of Things) system that wirelessly collects sensing information generated in mountainous areas, at sea, on islands, farms, or ranches using communication nodes composed of flying objects such as drones or aircraft has attracted attention. In the above-mentioned various places, the conventional terrestrial network may not be sufficiently laid. Therefore, the sensing information generated in the above-mentioned various places may be transmitted to a ground station via a NTN (Non-Terrestrial Network) composed of a plurality of communication nodes such as drones and collected at this ground station.

[0003] In this regard, for example, Patent Document 1 discloses an invention related to a wireless communication system that optimizes the topology in a multi-layer wireless communication network. This wireless communication system includes a geostationary satellite (GEO satellite) and a plurality of node stations. When the geostationary satellite collects communication state information from each node station, it determines the topology of the entire NTN based on the collected communication state information and distributes information regarding the determined topology to each node station. Note that the communication state information is information regarding the bandwidth utilization rate of a communication link established between node stations and the delay time of the communication link.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, in the NTN-based system described above, there may be cases where one of the communication nodes constituting the NTN becomes unable to receive information. For example, this may occur if there is an interference source near the communication node in question, or if there is some problem with the information receiving function of that communication node. In this case, the system needs to move another communication node to a location where it can receive sensing information and collect information anew. Furthermore, information regarding the transmission path of the information in such cases (hereinafter referred to as "transmission path information") needs to be shared among each communication node.

[0006] In this scenario, if transmission path information is shared among multiple communication nodes via each node, then if a particular communication node becomes unable to receive information, the transmission and reception of transmission path information will stop at that node, resulting in a problem where the transmission path information is not shared across the entire NTN network. Furthermore, in such a case, the system may be unable to establish a transmission path between communication nodes, potentially causing delays in the transmission of sensing information. It should be noted that these problems are not addressed in the aforementioned Patent Document 1.

[0007] This disclosure was made to solve the above-mentioned problems and aims to provide a network system that can collect information stably and at high speed while taking into account the state of the communication nodes that constitute NTN. [Means for solving the problem]

[0008] The network system described herein is configured to include a plurality of communication nodes that wirelessly receive information to be collected and transmit the received information to each other, and a relay station that can simultaneously send and receive information with each communication node. Each communication node transmits status information relating to its own status to the relay station, the relay station receives the status information from each communication node, and distributes node control information, which is generated using the received status information and is used to control the operation of each communication node, to each communication node, and each communication node receives the node control information from the relay station and is controlled to transmit the information to be collected to each other based on the received node control information. [Effects of the Invention]

[0009] According to this disclosure, the above configuration makes it possible to collect information stably and at high speed while taking into account the state of the communication nodes that make up NTN. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows an example of the configuration of the network system according to Embodiment 1. [Figure 2] This is a sequence chart showing an example of the operation of the network system according to Embodiment 1. [Figure 3] This figure shows an example of the configuration of a network system according to Embodiment 2. [Figure 4] This figure shows an example of the configuration of a network system according to Embodiment 4. [Figure 5] This figure shows an example of the arrangement of communication nodes based on topology information in Embodiment 5. [Figure 6] This figure shows an example of the configuration of a network system according to Embodiment 6. [Modes for carrying out the invention]

[0011] The embodiments will be described in detail below with reference to the drawings. Embodiment 1. Figure 1 shows an example configuration of a network system 1 according to Embodiment 1. As shown in Figure 1, the network system 1 is composed of a relay station 2, a plurality of communication nodes 3 (3A, 3B, 3C), a first ground station 4, a computing device 5, and a second ground station 6.

[0012] (Relay station 2) Relay station 2 is a mobile base station capable of simultaneously sending and receiving information with multiple communication nodes 3. Relay station 2 is capable of moving at a higher altitude than the multiple communication nodes 3. Here, relay station 2 is assumed to be composed of a geostationary satellite. However, relay station 2 is not limited to a geostationary satellite; it may also be composed of a mobile device capable of moving at a higher altitude than the multiple communication nodes 3, such as a balloon or a drone.

[0013] Relay station 2 receives information regarding the status of each communication node 3 (hereinafter referred to as "status information") from each communication node 3 (white arrows in Figure 1). Upon receiving status information from each communication node 3, relay station 2 transmits the received status information to the first ground station 4. Relay station 2 also receives node control information generated based on the status information by a computing device 5 installed at the first ground station 4 from the first ground station 4. Upon receiving node control information from the first ground station 4, relay station 2 simultaneously distributes the received node control information to each communication node 3 (black arrows in Figure 1).

[0014] Furthermore, the communication bandwidth and modulation / demodulation method used by the relay station 2 when transmitting and receiving information with each communication node 3 or the first ground station 4 are not particularly limited. For example, the communication bandwidth used for transmitting and receiving information between the relay station 2 and the communication node 3 is not limited to the radio wave band, but may also be the visible light band, etc.

[0015] (Communication node 3) Communication node 3 is a mobile device capable of sending and receiving information between relay station 2 and other communication nodes 3. Communication nodes 3 are comprised of, for example, drones or aircraft. Each communication node 3 transmits information about its own status (status information) to relay station 2 at predetermined time intervals.

[0016] The status information is configured to include, for example, information regarding the positions of each communication node 3 and information regarding the status of the devices mounted on each communication node 3. The information regarding the positions of each communication node 3 is obtained, for example, using a GPS (Global Positioning System) pre-mounted on each communication node 3. The devices mounted on each communication node 3 are, for example, communication devices capable of performing wireless communication, and are communication devices capable of transmitting information to each other between the devices mounted on other communication nodes 3 and the terminals 7 described later. The information regarding the status of the devices is, for example, information indicating that the devices are operating normally, or information indicating that some abnormality or failure has occurred in the devices.

[0017] In addition, each communication node 3 receives information to be collected (hereinafter referred to as "collection information") transmitted from the terminal 7 using the above-described devices. The collection information is, for example, sensing information collected by the terminal 7.

[0018] The terminal 7 is installed at a predetermined location, for example, in a mountainous area, at sea, in an island area, on a farm, or on a ranch, and collects various sensing information that can be collected at the location. The terminal 7 is configured to be capable of wireless communication with a communication node 3 located within a range where it can communicate with itself, and transmits the collected sensing information to the communication node 3 located within a range where it can communicate with itself at a predetermined time interval.

[0019] Each communication node 3 receives the collection information transmitted from the terminal 7 located within a range where it can communicate with itself. When each communication node 3 receives the collection information from the terminal 7, it transmits the received collection information to each other according to a transmission path determined based on topology information described later. Thereby, the communication node 3 transmits the collection information to the second ground station 6.

[0020] Furthermore, the communication bandwidth and modulation / demodulation method used by each communication node 3 when sending and receiving information with the relay station 2, other communication nodes 3, or the second ground station 6 are not particularly limited. For example, the communication bandwidth used for sending and receiving information between one communication node 3 and another communication node 3 is not limited to the radio wave band, but may also be the visible light band, etc.

[0021] (First Ground Station 4) The first ground station 4 is a base station installed on the ground and is capable of sending and receiving information with the relay station 2. The first ground station 4 receives status information of each communication node 3 transmitted from the relay station 2. Upon receiving status information transmitted from the relay station 2, the first ground station 4 outputs the received status information to the computing device 5. The first ground station 4 also transmits node control information generated by the computing device 5 to the relay station 2.

[0022] (calculating device 5) The computing device 5 comprises a state information database 51 and a topology computing device 52, and is installed at the first ground station 4. While this description describes an example where the computing device 5 is installed at the first ground station 4, the installation location of the computing device 5 is not limited to this. For example, the computing device 5 may be installed at a location other than the first ground station 4, as long as it is able to communicate with the first ground station 4 via a network not shown.

[0023] The status information database 51 is a functional unit for storing status information of each communication node 3 output from the first ground station 4. The status information database 51 is composed of, for example, an HDD (Hard Disk Drive) or an SSD (Solid State Drive).

[0024] The topology calculation device 52 generates topology information and equipment control information by performing predetermined calculations using the state information of each communication node 3 output from the first ground station 4. The topology information includes information regarding the arrangement of each communication node 3 and information regarding the information transmission path between each communication node 3.

[0025] Information regarding the placement of each communication node 3 includes, for example, information indicating the next location where each communication node 3 should be positioned. Information regarding the information transmission path between each communication node 3 includes, for example, information indicating which communication nodes will transmit information to which other communication nodes, and the direction of information transmission in that case. This information defines the information transmission path composed of each communication node 3 that is predetermined to be placed based on the placement information.

[0026] Furthermore, the equipment control information is information for realizing the arrangement of each communication node 3 and the information transmission path between each communication node 3, and is used for setting up each communication node 3 itself and the equipment installed in each communication node 3. Here, node control information for controlling the operation of each communication node 3 is formed by including the topology information and equipment control information described above. The node control information generated by the topology calculation device 52 is transmitted from the first ground station 4 to the relay station 2. In this explanation, we describe an example in which device control information is generated by the topology calculator 52. However, the device control information is not limited to this example and may be generated by a calculator other than the topology calculator 52 installed in the calculator 5, for example.

[0027] (Second ground station 6) The second ground station 6 is a base station installed on the ground, capable of sending and receiving information with one or more of the multiple communication nodes 3. The second ground station 6 is responsible for aggregating the collected information received by each communication node 3 and performing predetermined processing. For example, the second ground station 6 forwards the information to be collected received from one or more communication nodes 3 to other ground stations (not shown) connected via a network (not shown). Alternatively, the second ground station 6 performs predetermined analysis using the received information to be collected.

[0028] Next, an example of the operation of network system 1 will be explained with reference to the sequence charts shown in Figures 1 and 2. Note that the following explanation describes the case where there are three communication nodes 3 (3A to 3C), but the number of communication nodes 3 is not limited to these; there may be two, four or more, etc.

[0029] First, each communication node 3 transmits information about its own status (status information) to the relay station 2 (step ST1). Now, for example, as shown in Figure 1, suppose some abnormality or failure occurs in the equipment installed in communication node 3A, and communication with terminal 7 is lost. At this time, communication node 3A transmits to the relay station 2 the status information, which includes information indicating its own location and information indicating that an abnormality or failure has occurred in the equipment.

[0030] Next, relay station 2 receives status information transmitted from each communication node 3 (step ST2).

[0031] Next, relay station 2 transmits the status information received from each communication node 3 to the first ground station 4 (step ST3).

[0032] Next, the first ground station 4 receives status information transmitted from the relay station 2 (step ST4).

[0033] Next, the first ground station 4 outputs the status information received from the relay station 2 to the computing device 5 (topology computing device 52). When the topology computing device 52 acquires the status information output from the first ground station 4, it generates node control information using the acquired status information (step ST5).

[0034] For example, the topology calculator 52 generates topology information and equipment control information as node control information by performing predetermined calculations using the status information received from the relay station 2. At this time, the topology calculator 52 refers to the status information and determines that some abnormality or failure has occurred in the equipment installed in the communication node 3A. The topology calculator 52 then generates topology information to move the communication node 3B, which is not experiencing any abnormality or failure, to a position near the communication node 3A where it can receive the collected information transmitted from the terminal 7. At this time, one communication node or multiple communication nodes may be moved to a position where the collected information can be received. Also, when multiple communication nodes are moved, the multiple communication nodes may receive the same collected information.

[0035] The topology calculator 52 outputs the generated node control information to the first ground station 4. When the first ground station 4 receives the node control information from the topology calculator 52, it transmits the received node control information to the relay station 2 (step ST6).

[0036] Next, relay station 2 receives node control information transmitted from the first ground station 4 (step ST7).

[0037] Next, relay station 2 distributes the node control information received from the first ground station 4 to each communication node 3 simultaneously (step ST8).

[0038] Next, each communication node 3 receives node control information distributed simultaneously from relay station 2 (step ST9).

[0039] Next, each communication node 3 either moves to its designated location or remains stationary at its current location based on the topology information contained in the node control information received from the relay station 2. Furthermore, each communication node 3 configures the equipment installed on it based on the equipment control information contained in the node control information received from the relay station 2. This establishes an information transmission path for each communication node 3 (step ST10).

[0040] Furthermore, the node control information distributed simultaneously from relay station 2 is not node control information for a specific communication node 3, but rather node control information for all communication nodes 3. Therefore, each communication node 3 selects the node control information relevant to itself from the node control information received from relay station 2 and performs actions such as movement and equipment configuration.

[0041] Next, each communication node 3 receives collected information (e.g., sensing information) transmitted from a terminal 7 that is within communication range of the unit (step ST11).

[0042] Next, each communication node 3 transmits the collected information received from the terminal 7 to each other according to the transmission path established in step ST10. As a result, the communication nodes 3 transmit the collected information to the second ground station 6 (step ST12).

[0043] Next, the second ground station 6 receives the collected information transmitted from the communication node 3 (step ST13). Subsequently, the second ground station 6 performs predetermined processing on the received collected information.

[0044] Next, the effects of the network system 1 according to Embodiment 1 and the communication method using the network system 1 will be described. For example, in a network system using NTN, if one of the communication nodes that make up NTN becomes unable to receive information, it is necessary to move another communication node to a location where it can receive sensing information and collect new information. In addition, information regarding the transmission path (transmission path information) in this case needs to be shared among all communication nodes.

[0045] In conventional network systems, if transmission path information is shared among multiple communication nodes via each node, then if a particular communication node becomes unable to receive information, the transmission and reception of transmission path information will stop at that node, resulting in a problem where the transmission path information is not shared across the entire NTN network. Furthermore, in such a case, the system may be unable to establish a transmission path between communication nodes, potentially causing delays in the transmission of sensing information.

[0046] In contrast, the network system 1 according to Embodiment 1, as described above, includes a mobile relay station 2 capable of simultaneously sending and receiving information with each communication node 3. The relay station 2 is used exclusively for receiving status information from the communication nodes 3 and distributing information for controlling the operation of the communication nodes 3 (node ​​control information), while the transmission of collected information is limited to between the communication nodes 3. In other words, the network system 1 according to Embodiment 1 utilizes the characteristics of both the relay station 2, which can simultaneously distribute information over a relatively wide area, albeit with some delay, and the communication node 3, which can send and receive information relatively quickly, albeit over a narrow area. Information for controlling the operation of the communication nodes 3 is distributed simultaneously from the relay station 2 to each communication node 3, and the communication network between the communication nodes 3 is used for transmitting collected information. Thus, the transmission paths are divided according to the type of information to be transmitted. A small delay is not a problem if it is for controlling the operation of the communication nodes 3. Furthermore, the narrow coverage of the communication nodes 3 can be compensated for by a communication network (transmission path) constructed by multiple communication nodes 3, taking into account the state of each communication node 3. As a result, the network system 1 according to Embodiment 1 makes it possible to construct an information gathering network that can perform stable and high-speed information gathering while taking into account the state of the communication nodes.

[0047] Next, the advantages of the network system 1 according to Embodiment 1 compared to the wireless communication system disclosed in Patent Document 1 (hereinafter referred to as the "conventional system") will be supplemented by the following points (1) to (4). (1) Conventional systems build networks using a non-regenerative relay method. On the other hand, network system 1 does not distinguish between regenerative and non-regenerative relay methods. (2) In conventional systems, high-altitude platforms, low-Earth orbit satellites, and geostationary satellites communicate with each other to build a network, so these satellites and the like need to be equipped with communication equipment that can communicate with various platforms. On the other hand, in network system 1, it is sufficient for communication node 3 to have a line for communicating with relay station 2 and a line for communicating with other communication nodes 3. In this case, communication between communication node 3 and relay station 2 is used only for transmitting status information from communication node 3 to relay station 2 and for distributing node control information from relay station 2 to each communication node 3, so none of the above lines need to be high-capacity lines. Furthermore, since network system 1 does not assume that a wide variety of platforms such as satellites or drones will coexist as communication nodes 3, each communication node 3 does not need to be equipped with a large number of devices for communicating with a wide variety of platforms. Therefore, network system 1 can simplify the system configuration in this respect. (3) In conventional systems, low Earth orbit satellites can move, but their orbits are predetermined. On the other hand, in network system 1, it is assumed that communication node 3 has an undetermined orbit and can move freely. Therefore, network system 1 is superior to conventional systems in terms of scalability and flexibility. (4) In conventional systems, the information collected to build a network is the bandwidth utilization rate and latency of the communication links established between low Earth orbit satellites. In contrast, in network system 1, the status information of each communication node 3 is collected via relay station 2, which includes information about the location of each communication node 3 and information about the status of the equipment installed on each communication node 3. Therefore, in network system 1, the information collected to build a network can be simplified compared to conventional systems.

[0048] In the above description, an example was given in which the network system 1 includes a first ground station 4 and a computing device 5. However, if, for example, the functions of the first ground station 4 and the computing device 5 can be consolidated into the relay station 2, the first ground station 4 and the computing device 5 may be omitted. Also, in the above description, an example was given in which the network system 1 includes a second ground station 6. However, if, for example, the functions of the second ground station 6 can be consolidated into one of the communication nodes 3, the second ground station 6 may be omitted.

[0049] As described above, according to this embodiment 1, the network system 1 is configured to include a plurality of communication nodes 3 that wirelessly receive information to be collected and transmit the received information to each other, and a relay station 2 that can simultaneously send and receive information with each communication node 3. Each communication node 3 transmits status information regarding its own status to the relay station 2, the relay station 2 receives the status information from each communication node 3 and distributes node control information, which is generated using the received status information and is used to control the operation of each communication node 3, to each communication node 3. Each communication node 3 receives the node control information from the relay station 2 and is controlled to transmit the information to be collected to each other based on the received node control information. As a result, the network system 1 according to embodiment 1 can perform stable and high-speed information collection while taking into account the status of the communication nodes.

[0050] Furthermore, one or more of the multiple communication nodes 3 have a mobile function, and the status information includes information about the location of each communication node 3 and information about the status of the equipment installed in each communication node. The node control information includes topology information, which includes information about the arrangement of each communication node 3 and information about the information transmission path between each communication node 3, and equipment control information, which is used to configure the equipment installed in each communication node 3 in order to realize the arrangement and transmission path. Each communication node 3 configures the equipment installed on it based on the equipment control information contained in the node control information received from the relay station 2, and is positioned based on the topology information contained in the received node control information. It then transmits the information to be collected according to the transmission path based on the topology information. As a result, the network system 1 according to Embodiment 1 can appropriately position each communication node 3 and establish a transmission path while taking into account the state of each communication node 3.

[0051] Furthermore, the network system 1 includes a first ground station 4 that can communicate with a relay station 2, and a computing device 5 installed in the first ground station 4. The relay station 2 transmits status information received from each communication node 3 to the first ground station 4, and the first ground station 4 receives the status information from the relay station 2 and outputs the received status information to the computing device 5. The computing device 5 acquires the status information from the first ground station 4, generates topology information and equipment control information by performing predetermined calculations using the acquired status information, and outputs the generated topology information and equipment control information to the first ground station 4. The first ground station 4 acquires the topology information and equipment control information from the computing device 5 and transmits the acquired topology information and equipment control information to the relay station 2. As a result, the network system 1 according to Embodiment 1 can appropriately generate topology information and equipment control information based on the status information received from each communication node 3 and distribute it to each communication node 3.

[0052] Furthermore, the network system 1 includes a second ground station 6 capable of communicating with one or more of the multiple communication nodes 3, and each communication node 3 transmits the information to be collected to the second ground station 6 according to a transmission path based on topology information. As a result, the network system 1 according to Embodiment 1 can aggregate the information to be collected at the second ground station 6.

[0053] Furthermore, the relay station 2 is a geostationary satellite. As a result, the network system 1 according to Embodiment 1 can communicate accurately between the relay station 2 and each communication node 3.

[0054] Furthermore, according to Embodiment 1, the communication method is a communication method by a network system 1 comprising a plurality of communication nodes 3 that wirelessly receive information to be collected and transmit the received information to each other, and a relay station 2 that can simultaneously send and receive information with each communication node 3. Each communication node 3 transmits status information regarding its own status to the relay station 2, the relay station 2 receives the status information from each communication node 3, and distributes node control information, which is generated using the received status information and is used to control the operation of each communication node 3, to each communication node 3, each communication node 3 receives the node control information from the relay station 2, and is controlled to transmit the information to be collected to each other based on the received node control information. As a result, the communication method by the network system 1 according to Embodiment 1 can perform stable and high-speed information collection while taking into account the status of the communication nodes.

[0055] Embodiment 2. Embodiment 1 describes a network system 1 that can perform stable and high-speed information collection while taking into account the state of the communication node 3. Embodiment 2 describes a network system that can perform efficient information collection while suppressing the effects of interference waves transmitted from an interference wave source when an interference wave source exists near the network.

[0056] The configuration example of the network system 1 according to Embodiment 2 is basically the same as the configuration example of the network system 1 according to Embodiment 1 shown in Figure 1, but each communication node 3 in Embodiment 2 is equipped with an interference wave detection function. In addition, each communication node 3 transmits information regarding interference waves detected by the detection function (hereinafter referred to as "interference wave information") to the relay station 2 in addition to the state information described above. Furthermore, the topology calculation device 52 takes into account the interference wave information included in the state information in a predetermined calculation for generating the topology information described above.

[0057] Figure 3 shows an example configuration of the network system 1 according to Embodiment 2. In Figure 3, the interference wave source 10 is an object that transmits interference waves, such as a moving object such as a vehicle. Each communication node 3 is equipped with a function to detect interference waves transmitted from this interference wave source 10. For example, each communication node 3 detects interference waves based on the rate of increase of the bandwidth noise level. Generally, when interference waves are received, the bandwidth noise level rises sharply, so each communication node 3 detects interference waves when, for example, the rate of increase of the bandwidth noise level is above a threshold. Figure 3 shows an example in which communication node 3A loses communication with terminal 7 due to receiving interference waves. In addition to the interference wave detection function, each communication node 3 may also be equipped with a function to detect abnormalities in the reception of collected information due to the interference waves. However, each communication node 3 does not need to be equipped with a function to identify the location of the interference wave source 10.

[0058] When each communication node 3 transmits status information to the relay station 2, it includes interference wave information in the status information. The interference wave information includes, for example, information indicating whether or not the communication node 3 is being interfered with by an interference wave, or information indicating the intensity of the interference wave if it is being interfered with.

[0059] When the topology calculator 52 generates node control information using the state information, it takes into account the interference wave information contained in the state information. For example, the topology calculator 52 generates topology information so as not to use the interferenceed communication node 3A (so as not to be included in the information transmission path). In this case, the topology calculator 52 may generate topology information so as to place other communication nodes 3B that are not being interfered with in the vicinity of the interferenceed communication node 3A. The topology calculator 52 may also generate topology information so as to keep the interferenceed communication node 3A stationary at its current location, or it may generate topology information so as to move it to a different location. As a result, in the network system 1 according to Embodiment 2, efficient reception of collected information is possible while suppressing the effects of interference waves transmitted from the interference wave source 10.

[0060] As described above, according to this embodiment 2, each communication node 3 is equipped with an interference wave detection function, and transmits the interference wave information detected by the detection function to the relay station 2 in addition to the status information. The computing device 5 takes interference wave information into consideration in a predetermined calculation for generating topology information. As a result, the network system 1 according to Embodiment 2, in addition to the effects of Embodiment 1, can efficiently receive collected information while suppressing the effects of interference waves transmitted from the interference wave source 10.

[0061] Furthermore, if the interference wave information indicates that an interference wave has been detected, the computing device 5 generates topology information so as not to use the communication node 3A that transmitted the interference wave information for transmitting the information to be collected. As a result, the network system 1 according to Embodiment 2 can generate topology information in a manner that excludes communication nodes affected by interference waves.

[0062] Embodiment 3. Embodiment 2 describes a network system 1 that can efficiently collect information while suppressing the effects of interference waves transmitted from an interference wave source 10, even when such a source is present. Embodiment 3 describes a network system that can efficiently receive information while suppressing the possibility of interference target switching by the interference wave source 10.

[0063] The configuration example of the network system 1 according to Embodiment 3 is basically the same as the configuration example of the network system 1 according to Embodiment 2 shown in Figure 3. That is, each communication node 3 in Embodiment 3 is equipped with the interference wave detection function described above. Each communication node 3 also transmits information about the interference wave detected by the detection function (interference wave information) to the relay station 2 in addition to the state information. Furthermore, the topology calculation device 52 takes into account the interference wave information included in the state information in a predetermined calculation for generating the topology information described above.

[0064] For example, if the interference source 10 detects that a communication node 3 targeted for interference (e.g., communication node 3A shown in Figure 3) is moving, it may switch the interference target to another communication node 3 in response to that movement. Therefore, in the network system 1 according to Embodiment 3, the topology calculation device 52 generates topology information such that the position of the interferenceed communication node 3A is not changed, and one or more other communication nodes 3 are moved to positions where collected information can be received. As a result, the network system 1 according to Embodiment 3 can deceive the interferenceed communication node 3A into believing that it has taken countermeasures against interference, thereby suppressing the possibility of the interference target being switched by the interference source 10, and enabling efficient reception of collected information.

[0065] The topology calculation device 52 may generate topology information to move another communication node 3 (for example, communication node 3B shown in Figure 3) to a position where it can receive collected information, or it may generate topology information to move other communication nodes 3 (for example, communication nodes 3B and 3C shown in Figure 3) to positions where it can receive collected information. The topology calculation device 52 can estimate the position where the collected information can be received, for example, from the position of the communication node 3A that is experiencing interference and the position of the terminal 7 installed on the ground.

[0066] The topology calculator 52 may generate topology information multiple times when generating topology information to move other communication nodes 3. For example, even if other communication node 3B moves according to the initially generated topology information, its position may be outside the communication range with terminal 7, and as a result, it may not be able to receive the collected information. Therefore, other communication node 3B includes in its status information that it cannot receive the collected information and transmits the status information to the relay station 2 again. Then, the topology calculator 52 regenerates the topology information by performing a predetermined calculation again using the status information received from the relay station 2. Subsequently, other communication node 3B repeatedly transmits status information to the relay station 2 until it is able to receive the collected information, and the topology calculator 52 repeatedly generates topology information. In this way, by adaptively generating topology information, the topology calculator 52 ensures that other communication node 3B can reliably move within the communication range with terminal 7 and reliably receive the collected information.

[0067] As described above, according to this embodiment 3, when the interference wave information indicates that an interference wave has been detected, the computing device 5 generates topology information by determining the arrangement of other communication nodes without moving the position of the communication node 3A that transmitted the interference wave information. As a result, the network system 1 according to embodiment 3, in addition to the effects of embodiment 2, enables efficient reception of collected information while suppressing the possibility that the interference target will be switched by the interference wave source 10.

[0068] Furthermore, other communication nodes repeatedly transmit status information to the relay station 2, and the computing device 5 adaptively generates topology information by repeatedly performing predetermined calculations using the status information received from the relay station 2. This ensures that other communication nodes can reliably receive the collected information.

[0069] Embodiment 4. Embodiment 2 describes a network system 1 that can efficiently collect information while suppressing the effects of interference waves transmitted from an interference wave source 10, even when such an interference wave source 10 is present. Embodiment 4 describes a network system that can estimate the direction of arrival of interference waves transmitted from an interference wave source 10.

[0070] Figure 4 shows an example configuration of the network system 1 according to Embodiment 4. The example configuration of the network system 1 according to Embodiment 4 is basically the same as the example configuration of the network system 1 according to Embodiment 2 shown in Figure 3. That is, each communication node 3 in Embodiment 3 is equipped with the interference wave detection function described above. Each communication node 3 also transmits information about the interference wave detected by the detection function (interference wave information) to the relay station 2 in addition to the state information. Furthermore, the topology calculation device 52 considers the interference wave information included in the state information in a predetermined calculation for generating the topology information described above.

[0071] On the other hand, the configuration example of the network system 1 according to Embodiment 4 shown in Figure 4 is the same as the configuration example of the network system 1 according to Embodiment 2 shown in Figure 3, but with the addition of an interference position estimation device 53 to the computing device 5.

[0072] The interference position estimation device 53 estimates the direction of arrival of the interference wave based on the state information transmitted from each communication node 3.

[0073] The topology calculation device 52 generates topology information or equipment control information so that each communication node 3 suppresses the reception of information to be collected from the direction of arrival of the interference wave estimated by the interference position estimation device 53. For example, the topology calculation device 52 generates topology information or equipment control information so that each communication node 3 can control the orientation of its own device in order to suppress the sensitivity of receiving information in the direction of arrival of the interference wave.

[0074] For example, if each communication node 3 is equipped with an antenna for transmitting and receiving information, each communication node 3 controls its orientation based on topology information so that the antenna is oriented in the opposite direction to the direction of arrival of the interference wave. Also, if the equipment installed in each communication node 3 has a beamforming function, each communication node 3 performs beam combining based on equipment control information so that it is not sensitive to the direction of arrival of the interference wave.

[0075] The interference position estimation device 53 can estimate the direction of arrival of the interference wave by, for example, the following method. For example, if the status information transmitted from the communication node 3A shown in Figure 4 includes interference wave information, the interference location estimation device 53 determines, based on the interference wave information, whether the communication node 3A that transmitted the interference wave information has two or more antennas. If the interference location estimation device 53 determines that the communication node 3A that transmitted the interference wave information has two or more antennas, it estimates the direction of arrival of the interference wave based on the interference wave information received from the communication node 3A.

[0076] For example, in a communication node 3A equipped with two antennas, the time at which each antenna receives the interference wave may differ. In other words, in a communication node 3A equipped with two antennas, there may be a difference in the time it takes for the interference wave to reach each antenna. Communication node 3A includes information about this time difference in the interference wave information, includes this interference wave information in the status information, and then transmits the status information to relay station 2.

[0077] The interference location estimation device 53 determines that the communication node 3A that transmitted the interference wave information has two or more antennas if the interference wave information included in the state information includes information about a time difference. In this case, the interference location estimation device 53 can estimate the approximate direction of arrival of the interference wave using a known method, based on the time difference indicated by the information about the time difference. For example, the interference location estimation device 53 estimates the approximate direction of arrival of the interference wave based on the time difference indicated by the information about the time difference and the position of the communication node 3A determined by the topology information.

[0078] On the other hand, if the interference location estimation device 53 determines that the communication node 3A that transmitted the interference wave information does not have two or more antennas, the topology calculation device 52 generates topology information such that at least one other communication node 3 is placed near the communication node 3A that transmitted the interference wave information. The generated topology information is transmitted from the first ground station 4 to the relay station 2 in the form of node control information, and distributed from the relay station 2 to each communication node 3. Each communication node 3 is then positioned based on the distributed topology information. Figure 4 shows an example in which communication node 3B is placed near communication node 3A.

[0079] The interference location estimation device 53 estimates the direction of arrival of the interference wave using interference wave information transmitted from the communication node 3A that transmitted the interference wave information (the communication node 3A being interfered with), which is arranged based on topology information, and from at least one other communication node 3B. In this case, the interference location estimation device 53 estimates the approximate direction of arrival of the interference wave based on the position of the communication node 3A being interfered with, which is determined by topology information, the position of at least one other communication node 3B located near the communication node 3A being interfered with, and the difference in the time of reception of the interference wave (time difference) contained in the interference wave information received from each of these communication nodes 3A and 3B. As a result, in the network system 1 according to Embodiment 4, efficient reception of collected information is possible while suppressing the reception of information to be collected from the direction of arrival of the interference wave.

[0080] As described above, according to this embodiment 4, the computing device 5 can estimate the direction of arrival of the interference wave based on state information, and generates topology information or equipment control information so that each communication node 3 can suppress the reception of information to be collected from the estimated direction of arrival of the interference wave. As a result, the network system 1 according to embodiment 4, in addition to the effects of embodiment 2, can efficiently receive collected information while suppressing the reception of information to be collected from the direction of arrival of the interference wave.

[0081] Furthermore, the computing device 5 determines, based on the interference wave information, whether the communication node that transmitted the interference wave information has two or more antennas. If it determines that the communication node that transmitted the interference wave information has two or more antennas, it estimates the direction of arrival of the interference wave using the interference wave information received from the communication node. As a result, the network system 1 according to Embodiment 4 can easily estimate the direction of arrival of the interference wave.

[0082] Furthermore, if the computing device 5 determines that the communication node that transmitted the interference wave information does not have two or more antennas, it generates topology information such that at least one other communication node is placed near the communication node that transmitted the interference wave information, and estimates the direction of arrival of the interference wave using the interference wave information transmitted from the communication node that transmitted the interference wave information and at least one other communication node, which are positioned based on the generated topology information. As a result, the network system 1 according to Embodiment 4 can improve the accuracy of estimating the direction of arrival of the interference wave.

[0083] Embodiment 5. Embodiment 4 describes a network system that enables efficient reception of collected information while suppressing the reception of information to be collected from the direction of arrival of interference waves. Embodiment 5 describes a network system that can estimate the three-dimensional position of the interference wave source and determine a topology that minimizes the effects of interference while receiving collected information.

[0084] The configuration example of the network system 1 according to Embodiment 5 is basically the same as the configuration example of the network system 1 according to Embodiment 4 shown in Figure 4. That is, each communication node 3 in Embodiment 5 is equipped with the interference wave detection function described above. Furthermore, the network system 1 according to Embodiment 5 is equipped with an interference location estimation device 53.

[0085] In Embodiment 5, if the interference wave information indicates that an interference wave has been detected, the topology calculation device 52 designates the communication node 3 that transmitted the interference wave information as the interfered node, and generates topology information such that at least two other communication nodes are located near this interfered node. Then, the interference position estimation device 53 estimates the three-dimensional position of the interference wave source 10 using the interference wave information transmitted from the interfered node and the other communication nodes, which are arranged based on the topology information.

[0086] Figure 5 shows an example of the arrangement of communication nodes based on topology information. For example, the topology calculator 52 designates the interference-stricken communication node 3A as the interference-stricken node and generates topology information such that the other communication nodes 3B and 3C are arranged at a distance R from the interference-stricken node 3A. The other communication nodes 3B and 3C are arranged on a sphere with radius R centered on the interference-stricken node 3A. In this case, it is desirable that the distance (radius of the sphere) R be as small as possible without affecting the movement of each communication node.

[0087] As described above, communication nodes 3A to 3C receive interference waves transmitted from the interference wave source 10. Upon receiving interference waves, communication nodes 3A to 3C include the interference wave information in their status information and transmit it to relay station 2. Relay station 2 transmits the status information received from communication nodes 3A to 3C to the first ground station 4. The first ground station 4 receives the status information transmitted from relay station 2.

[0088] The interference position estimation device 53 estimates the three-dimensional position of the interference wave source 10 using a known method, based on interference wave information contained in the state information transmitted from communication nodes 3A to 3C and information regarding the positions of communication nodes 3A to 3C based on topology information.

[0089] Furthermore, if interference wave information cannot be obtained at any of the communication nodes 3A to 3C, the topology calculation device 52 may regenerate the topology information so that other communication nodes 3D are positioned at a distance R from the interfered node 3A. After positioning based on the regenerated topology information, each communication node 3A to 3D may attempt to receive interference wave information again. Here, if at least two other communication nodes are positioned on a sphere with radius R centered on the interfered node 3A, and at least three communication nodes, including the interfered node 3A, can receive interference wave information, the three-dimensional position of the interference wave source 10 can be estimated.

[0090] The information indicating the three-dimensional position of the interference source 10, estimated by the interference position estimation device 53, is output to the topology calculation device 52. The topology calculation device 52 then generates the next node control information, taking into account the information indicating the three-dimensional position of the interference source 10. As a result, in the network system 1 according to Embodiment 5, the three-dimensional position of the interference source 10 can be estimated, and a topology can be determined that receives collected information while minimizing the effects of interference.

[0091] In the above explanation, we described an example where the other communication nodes 3B to 3D are arranged on a sphere of radius R centered on the interfered node 3A. However, the other communication nodes 3B to 3D do not necessarily have to be arranged on the above sphere; for example, they may be arranged in a location other than the above sphere, as long as it is in the vicinity of the interfered node 3A. However, when the other communication nodes 3B to 3D are arranged on a sphere of radius R centered on the interfered node 3A, the positions of the other communication nodes 3B to 3D centered on the interfered node 3A become clear, the balance of the arrangement of each communication node improves, and the three-dimensional position of the interference wave source 10 can be estimated accurately and easily.

[0092] As described above, according to this embodiment 5, when the interference wave information indicates that an interference wave has been detected, the computing device 5 generates topology information such that at least two other communication nodes are placed near the interfered node 3A, which is the communication node that transmitted the interference wave information. Based on the generated topology information, the computing device 5 uses the interference wave information transmitted from the interfered node 3A and the other communication nodes to estimate the three-dimensional position of the interference wave source 10. As a result, the network system 1 according to embodiment 5 can estimate the three-dimensional position of the interference wave source 10 in addition to the effects of embodiment 4, and can determine a topology that receives collected information while minimizing the effects of interference.

[0093] Furthermore, the computing device 5 generates topology information such that at least two other communication nodes are arranged on a sphere having a predetermined radius centered on the interfered node 3A. As a result, the network system 1 according to embodiment 5 can accurately and easily estimate the three-dimensional position of the interference source 10.

[0094] Embodiment 6. Embodiment 5 describes a network system 1 that can estimate the three-dimensional position of the interference source 10 and determine a topology for receiving collected information while minimizing the effects of interference. Embodiment 6 describes a network system that can estimate the visible region of the interference source 10 and enhance the mobility safety of each communication node 3.

[0095] Figure 6 shows an example configuration of the network system 1 according to Embodiment 6. Compared to the example configuration of the network system 1 according to Embodiment 6 shown in Figure 4, the computing device 5 has a visible area estimation device 54, a travel path calculation device 55, and a terrain information database 56 added to it.

[0096] The visible region estimation device 54 estimates the visible region of the interference wave source 10 using the interference wave information contained in the state information transmitted from each communication node 3 and the information indicating the three-dimensional position of the interference wave source 10 estimated by the interference position estimation device 53. The visible region of the interference wave source 10 generally coincides with the sensitivity region of the interference wave.

[0097] For example, the visible area estimation device 54 can, to some extent, grasp the reception status of interference waves around the interference wave source 10 by using the interference wave information transmitted from each communication node 3. Therefore, the visible area estimation device 54 can estimate the visible area (interference wave sensitivity area) of the interference wave source 10 from the estimated position of the interference wave source 10 and the reception status of interference waves around the interference wave source 10, using the information indicating the three-dimensional position of the interference wave source 10 estimated by the interference position estimation device 53. In this estimation, the topology calculation device 52 may repeatedly generate topology information and repeatedly change the arrangement of each communication node 3, and the visible area estimation device 54 may instruct each communication node 3 to transmit interference wave information each time it is arranged.

[0098] Once the visible region estimation device 54 estimates the visible region of the interference wave source 10, the topology calculation device 52 generates topology information such that each communication node 3 is positioned in a region other than the visible region of the interference wave source 10 estimated by the visible region estimation device 54.

[0099] The topographic information database 56 stores information about topography. Topographic information includes various types of information about the shape or structure of the ground, such as elevation, contour lines, slopes and inclines at each point, topographic classification (mountains, valleys, plateaus, etc.), ground surface shape, water systems (rivers, lakes, etc.), and information about artificial structures.

[0100] The movement path calculation device 55 calculates the movement path of each communication node 3. For example, when calculating the movement path of each communication node 3 so that it is arranged according to the topology information generated by the topology calculation device 52, the movement path calculation device 55 considers at least one of the topographic information stored in the topographic information database 56 or the visible area of ​​the interference wave source 10 estimated by the visible area estimation device 54.

[0101] For example, when the movement path calculation device 55 calculates the movement path of each communication node 3, it can consider the terrain information stored in the terrain information database 56 to calculate a path that allows each communication node 3 to move while maintaining a sufficient altitude so as not to collide with, for example, mountains or artificial structures. The movement path information calculated by the movement path calculation device 55 is distributed to each communication node 3, for example, in topology information. As a result, each communication node 3 can move safely without colliding with, for example, mountains or artificial structures.

[0102] Furthermore, when the movement path calculation device 55 calculates the movement path of each communication node 3, if it takes into account the visible area of ​​the interference wave source 10 estimated by the visible area estimation device 54, it can calculate a path that each communication node 3 can travel without passing through the visible area of ​​the interference wave source 10. The movement path information calculated by the movement path calculation device 55 is distributed to each communication node 3, for example, by being included in topology information. As a result, each communication node 3 can move while avoiding detection by the interference wave source 10.

[0103] As described above, the network system 1 according to Embodiment 6 can estimate the visible region of the interference wave source 10 and generate topology information to arrange the communication nodes 3 in regions other than the visible region. Furthermore, the network system 1 according to Embodiment 6 can enhance the mobility safety of each communication node 3.

[0104] As described above, according to this embodiment 6, the computing device 5 uses the interference wave information transmitted from each communication node 3 and the information indicating the estimated three-dimensional position of the interference wave source 10 to estimate the visible region of the interference wave source 10, and generates topology information so that each communication node 3 is placed in a region other than the estimated visible region of the interference wave source 10. As a result, the network system 1 according to embodiment 6 can estimate the visible region of the interference wave source 10 and generate topology information so that the communication nodes 3 are placed in a region other than the visible region, in addition to the effects of embodiment 5.

[0105] Furthermore, the computing device 5 can calculate the movement path of each communication node 3, and when calculating the movement path of each communication node 3 so that it is arranged according to topology information, it considers at least one of the terrain information stored in the terrain information database 56 or the visible area of ​​the estimated interference wave source 10. As a result, the network system 1 according to embodiment 6 can enhance the movement safety of each communication node 3.

[0106] Although preferred embodiments have been described in detail above, the invention is not limited to the embodiments described above, and various modifications and substitutions can be made to the embodiments described above without departing from the scope of the claims.

[0107] Furthermore, this disclosure allows for free combination of each embodiment, modification of any component of each embodiment, or omission of any component in each embodiment. [Industrial applicability]

[0108] This disclosure enables stable and high-speed information gathering while taking into account the state of the communication nodes constituting NTN, and is suitable for use in network systems and communication methods. [Explanation of symbols]

[0109] 1 Network system, 2 Relay station, 3, 3A, 3B, 3C, 3D communication node, 4 First ground station, 5 Computing unit, 6 Second ground station, 7 Terminal, 10 Interference wave source, 51 State information database, 52 Topology computing unit, 53 Interference position estimation unit, 54 Visible area estimation unit, 55 Movement path computing unit, 56 Topographic information database.

Claims

1. Multiple communication nodes that wirelessly receive the information to be collected and that can transmit the received information to each other, A relay station capable of simultaneously sending and receiving information with each of the aforementioned communication nodes, It consists of, Each of the aforementioned communication nodes transmits status information regarding the status of its own device to the relay station. The relay station receives the status information from each of the communication nodes, and distributes node control information, which is generated using the received status information and is used to control the operation of each of the communication nodes, to each of the communication nodes. Each of the aforementioned communication nodes receives node control information from the relay station and is controlled to transmit the information to be collected to each other based on the received node control information. A network system characterized by the following:

2. One or more of the aforementioned communication nodes have a mobile function. The status information includes information regarding the location of each communication node and information regarding the status of the equipment installed in each communication node. The node control information is, Topology information including information regarding the arrangement of each communication node and information regarding the transmission path of information between each communication node, and equipment control information used to configure the equipment installed in each communication node in order to realize the arrangement and the transmission path, Each communication node configures the equipment installed on it based on the equipment control information contained in the node control information received from the relay station, and is arranged based on the topology information contained in the received node control information, and transmits the information to be collected according to the transmission path based on the topology information. The network system according to claim 1, characterized in that it is the same as described in claim 1.

3. A first ground station capable of communicating with the aforementioned relay station, The system includes a computing device installed at the first ground station, The relay station transmits the status information received from each of the communication nodes to the first ground station. The first ground station receives the status information from the relay station and outputs the received status information to the computing device. The computing device acquires the status information from the first ground station, generates the topology information and the equipment control information by performing predetermined calculations using the acquired status information, and outputs the generated topology information and equipment control information to the first ground station. The first ground station acquires the topology information and the equipment control information from the computing device and transmits the acquired topology information and the equipment control information to the relay station. The network system according to claim 2, characterized in that it is as described above.

4. Includes a second ground station capable of communicating with one or more of the aforementioned plurality of communication nodes, Each of the aforementioned communication nodes transmits the information to be collected to the second ground station according to the transmission path based on the topology information. The network system according to claim 2 or 3, characterized by the features described herein.

5. The relay station is a geostationary satellite. A network system according to any one of claims 1 to 3.

6. Each of the aforementioned communication nodes is equipped with an interference wave detection function, and transmits the interference wave information detected by the detection function to the relay station in addition to the status information. The computing device considers the interference wave information in the predetermined calculation for generating the topology information. The network system according to claim 3, characterized in that it is as described above.

7. If the aforementioned computing device indicates that interference wave information has been detected, it generates topology information such that the communication node that transmitted the interference wave information is not used for transmitting the information to be collected. The network system according to claim 6, characterized in that it is as described above.

8. When the aforementioned computing device indicates that interference wave information has been detected, it generates the topology information by determining the placement of other communication nodes without moving the position of the communication node that transmitted the interference wave information. The network system according to claim 6, characterized in that it is as described above.

9. The other communication node repeatedly transmits the status information to the relay station. The computing device adaptively generates the topology information by repeatedly performing the predetermined calculation using the state information received from the relay station. The network system according to claim 8, characterized in that it is as described above.

10. The computing device is capable of estimating the direction of arrival of the interference wave based on the state information, and generates the topology information or the equipment control information so that each communication node can suppress the reception of information to be collected from the estimated direction of arrival of the interference wave. The network system according to any one of claims 6 to 9.

11. The computing device determines, based on the interference wave information, whether the communication node that transmitted the interference wave information has two or more antennas. If it is determined that the communication node that transmitted the interference wave information has two or more antennas, the direction of arrival of the interference wave is estimated using the interference wave information received from that communication node. The network system according to claim 10, characterized in that it is the same as described above.

12. If the computing device determines that the communication node that transmitted the interference wave information does not have two or more antennas, Topology information is generated such that at least one other communication node is located near the communication node that transmitted the interference wave information, and the direction of arrival of the interference wave is estimated using the interference wave information transmitted from the communication node that transmitted the interference wave information and at least one other communication node, which are located based on the generated topology information. The network system according to claim 11, characterized in that it is a network system as described in claim 11.

13. If the interference wave information indicates that an interference wave has been detected, the computing device generates topology information such that at least two other communication nodes are placed near the interfered node, which is the communication node that transmitted the interference wave information. The three-dimensional position of the interference source is estimated using interference wave information transmitted from the interferenceed node and the other communication node, which are arranged based on the generated topology information. The network system according to any one of claims 6 to 9.

14. The computing device generates the topology information such that at least two of the other communication nodes are arranged on a sphere having a predetermined radius centered on the interfered node. The network system according to claim 13, characterized in that it is as described above.

15. The computing device uses the interference wave information transmitted from each of the communication nodes and the information indicating the estimated three-dimensional position of the interference wave source to estimate the visible region of the interference wave source, The topology information is generated such that each of the aforementioned communication nodes is positioned in a region other than the visible region of the estimated interference wave source. The network system according to claim 13, characterized in that it is as described above.

16. The aforementioned computing device is capable of calculating the movement path of each of the aforementioned communication nodes. When calculating the movement path of each communication node so that it is arranged according to the topology information, at least one of the terrain information stored in the terrain information database or the visible region of the estimated interference wave source is taken into consideration. The network system according to claim 15, characterized in that it is the same as described above.

17. Multiple communication nodes that wirelessly receive the information to be collected and that can transmit the received information to each other, A communication method using a network system comprising a relay station capable of simultaneously transmitting and receiving information with each of the aforementioned communication nodes, Each of the aforementioned communication nodes transmits status information regarding the status of its own device to the relay station. The relay station receives the status information from each of the communication nodes, and distributes node control information generated using the received status information, which is for controlling the operation of each of the communication nodes, to each of the communication nodes. Each of the aforementioned communication nodes receives node control information from the relay station and is controlled to transmit the information to be collected to each other based on the received node control information. A communication method characterized by the following features.

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