Communication system, first communication device, second communication device, third communication device, program, and communication method

Abstract

We provide technology that can improve communication quality. [Solution] The communication system comprises a first communication device, a second communication device, and a plurality of third communication devices, each having a limit on the transmission time per unit time. At least one of the plurality of third communication devices relays the first transmission data transmitted by the second communication device to the first communication device. The first communication device determines a plurality of first relay routes for relaying the first transmission data in the plurality of third communication devices, based on the limits. The second communication device distributes and relays the first transmission data across the plurality of first relay routes.

Description

Technical Field

[0001] The present disclosure relates to communications.

Background Art

[0002] Patent Document 1 discloses a technique related to communications.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] There is room for improvement in communications.

[0005] Accordingly, the present disclosure has been made in view of the above points, and an object thereof is to provide a technique that makes it possible to improve communication quality.

Means for Solving the Problem

[0006] One aspect of a communication system includes a first communication apparatus, a second communication apparatus, and a plurality of third communication apparatuses each having a limit on transmission time per unit time. At least one third communication apparatus among the plurality of third communication apparatuses relays first transmission data transmitted by the second communication apparatus to the first communication apparatus. The first communication apparatus determines a plurality of first relay routes for relaying the first transmission data in the plurality of third communication apparatuses based on the limit. The second communication apparatus distributes the first transmission data to the plurality of first relay routes for relaying.

[0007] Also, one aspect of the first communication apparatus is the first communication apparatus included in the above communication system.

[0008] Also, one aspect of the second communication apparatus is the second communication apparatus included in the above communication system.

[0009] Furthermore, one embodiment of the third communication device is a third communication device provided in the above-described communication system. The third communication device receives the first transmission data directly from the second communication device, or receives the first transmission data through another third communication device.

[0010] Another form of the program is one that causes a computer device to function as the first communication device described above.

[0011] Another form of the program is one that causes a computer device to function as the second communication device described above.

[0012] Another form of the program is one that causes a computer device to function as the third communication device described above.

[0013] Furthermore, in one aspect of the communication method, at least one of a plurality of third communication devices, each having a limit on the transmission time per unit time, relays the first transmission data transmitted by the second communication device to the first communication device, the first communication device determines a plurality of first relay routes for relaying the first transmission data in the plurality of third communication devices based on the limits, and the second communication device distributes and relays the first transmission data across the plurality of first relay routes. [Effects of the Invention]

[0014] It can improve communication quality. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 is a schematic diagram showing an example of the configuration of a communication system. [Figure 2] Figure 2 is a schematic diagram showing an example of the configuration of a communication system. [Figure 3] Figure 3 is a schematic diagram showing an example of a communication area. [Figure 4] Figure 4 is a schematic diagram showing an example of the configuration of the first communication device. [Figure 5] FIG. 5 is a schematic diagram showing an example of the configuration of a second communication apparatus. [Figure 6] FIG. 6 is a schematic diagram showing an example of the configuration of a third communication apparatus. [Figure 7] FIG. 7 is a flowchart showing an example of the operation of the third communication apparatus. [Figure 8] FIG. 8 is a schematic diagram showing an example of the operation of a communication system. [Figure 9] FIG. 9 is a flowchart showing an example of the operation of a first communication apparatus. [Figure 10] FIG. 10 is a flowchart showing an example of the operation of the first communication apparatus. [Figure 11] FIG. 11 is a flowchart showing an example of the operation of the first communication apparatus. [Modes for Carrying Out the Invention]

[0016] <Outline of Example of Communication System> FIG. 1 is a schematic diagram showing an example of a communication system 5. As shown in FIG. 1, the communication system 5 includes, for example, a first communication apparatus 1, at least one second communication apparatus 2, and a plurality of third communication apparatuses 3. In the example of FIG. 1, the communication system 5 includes a plurality of second communication apparatuses 2, but the number of the second communication apparatus 2 may be one. In FIG. 1, the first communication apparatus 1 is indicated by a black circle, the second communication apparatus 2 is indicated by dot hatching, and the third communication apparatus 3 is indicated by oblique hatching.

[0017] The third communication apparatus 3 is capable of, for example, direct wireless communication with the first communication apparatus 1. The third communication apparatus 3 is capable of, for example, direct wireless communication with the second communication apparatus 2. The third communication apparatus 3 is capable of direct wireless communication with other third communication apparatuses 3. When the distance to the first communication apparatus 1 is large, the third communication apparatus 3 can also communicate with the first communication apparatus 1 via another third communication apparatus 3. When the distance to the second communication apparatus 2 is large, the third communication apparatus 3 can also communicate with the second communication apparatus 2 via another third communication apparatus 3.

[0018] The second communication device 2 may or may not be able to communicate with other second communication devices 2. In the former case, the second communication device 2 may, for example, communicate wirelessly with other second communication devices 2. The second communication device 2 cannot communicate directly with the first communication device 1.

[0019] The first communication device 1 is located at a distance from each of the second communication devices 2. The first communication device 1 is located outside the communication area (in other words, the communication area) of each of the second communication devices 2. The first communication device 1 can communicate with the second communication devices 2 through the third communication device 3. The transmission data that the first communication device 1 sends to the second communication device 2 reaches the second communication device 2 through at least one third communication device 3. In other words, the transmission data that the first communication device 1 sends to the second communication device 2 is relayed by at least one third communication device 3 before reaching the second communication device 2. The transmission data that the second communication device 2 sends to the first communication device 1 is relayed by at least one third communication device 3 before reaching the first communication device 1. The third communication device 3 functions as a relay device that relays communication data between the first communication device 1 and the second communication device 2.

[0020] If the distance between the third communication device 3 and the first communication device 1 is large, the transmission data that the third communication device 3 sends to the first communication device 1 will be relayed by at least one other third communication device 3 before reaching the server 1. Also, if the distance between the third communication device 3 and the first communication device 1 is large, the transmission data that the server 1 sends to the third communication device 3 will be relayed by at least one other third communication device 3 before reaching the destination third communication device 3.

[0021] If the distance between the second communication device 2 and the third communication device 3 is large, the transmission data that the second communication device 2 sends to the third communication device 3 will be relayed by at least one other third communication device 3 before reaching the destination third communication device 3. Also, if the distance between the second communication device 2 and the third communication device 3 is large, the transmission data that the third communication device 3 sends to the second communication device 2 will be relayed by at least one other third communication device 3 before reaching the second communication device 2.

[0022] The first communication device 1 is, for example, a server capable of comprehensively managing the operation of the communication system 5. The first communication device 1 can control the second communication device 2 and the third communication device 3. The first communication device 1 can also be described as, for example, a higher-level device. Note that the first communication device 1 does not have to be a server. Hereafter, the first communication device 1 that is a server may be referred to as server 1. The second communication device 2 and the third communication device 3 controlled by server 1 can also be described as, for example, terminal devices in relation to server 1.

[0023] For example, the first communication standard between server 1 and third communication device 3 is different from the second communication standard between second communication device 2 and third communication device 3. It can also be said that the first communication method between server 1 and third communication device 3 is different from the second communication method between second communication device 2 and third communication device 3. Multiple third communication devices 3 can communicate with each other in accordance with the first communication standard. The first communication standard can also be said to be a communication standard between multiple third communication devices 3.

[0024] Server 1 is capable of communicating in accordance with only the first communication standard out of the two communication standards. Second communication device 2 is capable of communicating in accordance with only the second communication standard out of the two communication standards. Third communication device 3 is capable of communicating in accordance with both the first and second communication standards.

[0025] The frequency band of the first communication standard is smaller than, for example, the frequency band of the second communication standard. For example, the frequency band of the first communication standard is below 1 GHz, while the frequency band of the second communication standard is larger than 1 GHz.

[0026] The communication range of the first communication standard is greater than, for example, the communication range of the second communication standard. Communication range can also be called the possible communication range or the maximum communication range. For example, the communication range of the first communication standard is 300m or more, while the communication range of the second communication standard is 150m or less.

[0027] The first communication standard may be, for example, Wi-Fi HaLow as defined in IEEE 802.11ah. The frequency band of Wi-Fi HaLow is the 920 MHz band. The communication range of Wi-Fi HaLow is approximately 1 km. Wi-Fi HaLow is a type of LPWA (Low Power Wide Area Network).

[0028] The second communication standard may be, for example, Wi-Fi 6 as defined in IEEE 802.11ax. The frequency band for Wi-Fi 6 is the 2.4 Hz band or the 5 GHz band. The communication range of Wi-Fi 6 is approximately 100m.

[0029] In the communication system 5, a network 200 is configured with a second communication device 2 and a third communication device 3 that communicates with the second communication device 2 in accordance with Wi-Fi 6. In the Wi-Fi 6 compliant network 200, the second communication device 2 functions, for example, as an access point, and the third communication device 3 functions, for example, as a terminal device. Hereafter, for the sake of explanation, a Wi-Fi 6 compliant network 200 with a shorter communication range than Wi-Fi HaLow may be referred to as a short-range network 200. As shown in the example in Figure 1, if the communication system 5 has multiple second communication devices 2, the communication system 5 is configured with multiple short-range networks 200, each containing multiple second communication devices 2.

[0030] Furthermore, in the communication system 5, the network 100 is configured with a server 1 that communicates in accordance with Wi-Fi HaLow and multiple third communication devices 3. The network 100 can also be described as a long-distance network.

[0031] Network 100 can function as a mesh network, for example. That is, Server 1 and the multiple third communication devices 3 can form a mesh network. The mesh network formed by Server 1 and the multiple third communication devices 3 may be, for example, a mesh network compliant with EasyMesh. A mesh network that communicates based on Wi-Fi, such as an EasyMesh-compliant mesh network, is also called a Wi-Fi mesh or mesh Wi-Fi, for example. Server 1 can decide whether or not to make Network 100 function as a mesh network. Hereafter, when simply referring to a mesh network, it means the mesh network in which Network 100 functions (in this example, an EasyMesh-compliant mesh network).

[0032] The position of the second communication device 2 is, for example, fixed. Multiple second communication devices 2 are arranged in different locations. The communication area of ​​one second communication device 2 and the communication area of ​​another second communication device 2 may or may not partially overlap. The communication area can also be called the communication-enabled area.

[0033] Multiple third communication devices 3 are mounted, for example, on multiple mobile bodies 300 (see Figure 2 described later). The third communication devices 3 are movable in accordance with the movement of the mobile body 300 on which the third communication devices 3 are mounted. The third communication devices 3 can also be called mobile communication devices or mobile devices.

[0034] The mobile body 300 may be, for example, an animal, or a device such as an autonomous mobile robot. An autonomous mobile robot is also called an AMR, for example. AMR is an abbreviation for Autonomous Mobile Robot. The animal as the mobile body 300 may be, for example, livestock such as cattle and horses, or a person. The number of multiple mobile bodies 300 may be, for example, 10 or more, several tens, 100 or more, or several hundred. In other words, the number of multiple third communication devices 3 may be, for example, 10 or more, several tens, 100 or more, several hundred, or more than several hundred.

[0035] The communication system 5 in this example can, for example, monitor multiple mobile bodies 300 moving within a predetermined area 500. The communication system 5 can also be described as a monitoring system that monitors multiple mobile bodies 300. The third communication device 3 mounted on the mobile body 300 can move within the predetermined area 500. The predetermined area 500 can also be described as a monitoring area or a monitored area. Hereafter, the predetermined area 500 may be referred to as the monitoring area 500.

[0036] Figure 2 is a schematic diagram showing an example of a monitoring area 500. As shown in Figure 2, Server 1 and the second communication device 2 are arranged within the monitoring area 500. Within the monitoring area 500, Server 1 is positioned at a distance from the second communication device 2. For example, the communication area of ​​Server 1 and the communication area of ​​the second communication device 2 do not overlap. Server 1 and the second communication device 2 are positioned, for example, at the periphery of the monitoring area 500. Multiple second communication devices 2 may be arranged far apart from each other, as in the example in Figure 2, or they may be arranged close to each other. In the example in Figure 2, the area consisting of the communication areas of multiple second communication devices 2 provided by the communication system 5 covers a portion of the monitoring area 500.

[0037] Note that the positions of Server 1 and Second Communication Device 2 in the monitoring area 500 are not limited to the above example. For example, multiple Second Communication Devices 2 may be arranged in a matrix across the entire monitoring area 500, and the area consisting of the communication areas of these multiple Second Communication Devices 2 may cover the entire monitoring area 500.

[0038] As shown in the example in Figure 2, if the monitoring area 500 is a square, the length of one side of the monitoring area 500 may be set to several times (for example, four times) the communication distance of the third communication device 3 in the first communication standard (in this example, the communication distance of Wi-Fi HaLow). For example, if the communication distance of the third communication device 3 in the first communication standard is 1 km, the length of one side of the monitoring area 500 may be set to 4 km. This makes it possible to reduce the number of third communication devices 3 that relay data between the second communication device 2 and the server 1. The number of third communication devices 3 that relay data can also be called the number of hops. By reducing the number of hops, for example, the communication time between the second communication device 2 and the server 1 can be reduced. Also, by reducing the number of hops, the overhead that occurs when relaying data can be reduced, and as a result, for example, the data transmission efficiency between the second communication device 2 and the server 1 can be improved. As in this example, when the communication distance of the third communication device 3 moving within the monitoring area 500 is large, the monitoring area 500 can be set to be wide while reducing the number of hops. Note that the shape of the monitoring area 500 is not limited to the example in Figure 2.

[0039] The third communication device 3 is capable of acquiring data (also called mobile device-related data) related to the mobile device 300 on which the third communication device 3 is installed. The third communication device 3 is capable of transmitting the acquired mobile device-related data to the second communication device 2. Furthermore, the third communication device 3 is capable of transmitting the acquired mobile device-related data to the server 1.

[0040] The second communication device 2 can determine the state of the mobile body 300 on which the third communication device 3 is mounted, based on mobile body-related data received from the third communication device 3. The second communication device 2 also has, for example, a camera 230 (see Figure 5 below). The camera 230 is capable of taking pictures of the area around the second communication device 2. The second communication device 2 can determine the state of the mobile body 300 based on the camera image of the mobile body 300 obtained by the camera 230.

[0041] The second communication device 2 can transmit determination result data indicating the status of the mobile object 300 to the server 1 via at least one third communication device 3. The determination result data can also be described as mobile object-related data.

[0042] Server 1 can acquire and manage mobile-related data for each mobile object 300. For example, Server 1 receives and acquires judgment result data (in other words, mobile-related data) from the second communication device 2. Server 1 then stores the judgment result data acquired from the second communication device 2. Server 1 also receives and acquires mobile-related data from the third communication device 3. Server 1 then stores the mobile-related data acquired from the third communication device 3.

[0043] Figure 3 is a schematic diagram showing an example of the relationship between the communication area 120 of the second communication device 2, the shooting range 230a of the camera 230 of the second communication device 2, and the communication area 130 of the third communication device 3. The camera 230 is, for example, a PTZ camera with pan, tilt, and zoom functions. The camera 230 is capable of capturing a 360-degree range around it.

[0044] As shown in Figure 3, the communication area 130 of the third communication device 3 is larger than the communication area 120 of the second communication device 2. In Figure 3, for ease of explanation, the communication areas 120 and 130 are shown as concentric circles to make the relationship between their sizes easier to understand.

[0045] Furthermore, as shown in Figure 3, the shooting range 230a of the camera 230 of the second communication device 2 is larger than the communication area 120 of the second communication device 2 and includes the entire area of ​​the communication area 120. The radius of the shooting range 230a of the camera 230 is set to be larger than the communication distance of the second communication device 2 (in other words, the radius of the communication area 120). Also, the radius of the shooting range 230a of the camera 230 is set to be smaller than the communication distance of the first communication device 1 (in other words, the radius of the communication area 130). The camera 230 is capable of photographing the moving object 300 that is located within the communication area 120.

[0046] The size of the shooting range 230a of the camera 230 may be the same size as the communication area 120, or it may be smaller than the communication area 120. For example, the shooting range 230a of the camera 230 of the second communication device 2 may be included in the communication area 120 of the second communication device 2. Also, the shooting range 230a of the camera 230 of the second communication device 2 may partially overlap with the communication area 120 of the second communication device 2.

[0047] In the example shown in Figure 2, the area consisting of the shooting ranges 230a of the multiple cameras 230 each of the multiple second communication devices 2 covers a portion of the monitoring area 500. Alternatively, the multiple second communication devices 2 may be arranged, for example, in a matrix, across the entire monitoring area 500, so that the area consisting of the shooting ranges 230a of the cameras 230 of the multiple second communication devices 2 covers the entire monitoring area 500.

[0048] The first communication standard may be, for example, a different LPWA than Wi-Fi HaLow. For example, the first communication standard may be LoRa. Also, the second communication standard may be a communication standard other than Wi-Fi 6. For example, the second communication standard may be Wi-Fi 5 as defined in IEEE 802.11ac, or it may be BLE. BLE is an abbreviation for Bluetooth® Low Energy. Furthermore, the mesh network on which network 100 can function may conform to a standard other than EasyMesh. For example, network 100 may function as a mesh network conforming to IEEE 802.11s. Also, network 100 does not have to function as a mesh network.

[0049] <Example configuration of the first communication device (server)> Figure 4 is a schematic diagram showing an example configuration of the first communication device 1 (in other words, server 1). As shown in Figure 4, server 1 includes, for example, a control unit 10, a storage unit 11, and an interface 12. Server 1 is, for example, a computer device.

[0050] Interface 12 is capable of wireless communication with the third communication device 3 in accordance with the first communication standard. Interface 12 can also be called, for example, an interface circuit, a communication unit, or a communication circuit. Interface 12 inputs data received from the third communication device 3 to the control unit 10. Interface 12 also transmits data from the control unit 10 to the third communication device 3.

[0051] The control unit 10 can comprehensively manage the operation of server 1 by controlling other components of server 1. The control unit 10 can also be described as a processing unit that performs various processes. The control unit 10 can also be described as a control circuit or processing circuit. The control unit 10 includes, for example, at least one processor. The at least one processor included in the control unit 10 may include a CPU. CPU is an abbreviation for Central Processing Unit. The control unit 10 stores mobile-related data received at interface 12 in storage unit 11.

[0052] The storage unit 11 includes, for example, non-volatile memory and volatile memory. Non-volatile memory and volatile memory can also be described as non-temporary recording media that can be read by a processor such as a CPU. The storage unit 11 can also be described as, for example, a memory circuit.

[0053] The non-volatile memory of the storage unit 11 may include, for example, flash memory. The non-volatile memory of the storage unit 11 stores, for example, a program 11a for controlling the server 1. Various functions of the control unit 10 are realized, for example, by the CPU of the control unit 10 executing the program 11a.

[0054] The volatile memory of the storage unit 11 functions as work memory for data processing by the control unit 10. The volatile memory of the storage unit 11 may include, for example, SRAM (Static RAM) or DRAM (Dynamic RAM). RAM is an abbreviation for Random Access Memory.

[0055] The configuration of Server 1 is not limited to the example above. For example, the control unit 10 may include at least one processor, which may include multiple CPUs or at least one DSP (Digital Signal Processor). Furthermore, all or some of the functions of the control unit 10 may be implemented by hardware circuits that do not require software to perform those functions. In addition, the storage unit 11 may include, for example, a small hard disk drive and an SSD (Solid State Drive).

[0056] <Example of configuration for the second communication device> Figure 5 is a schematic diagram showing an example configuration of the second communication device 2. As shown in Figure 5, the second communication device 2 includes, for example, a control unit 20, a storage unit 21, an interface 22, and a sensor unit 23. The second communication device 2 is, for example, a computer device.

[0057] Interface 22 is capable of wireless communication with the third communication device 3 in accordance with the second communication standard. Interface 22 can also be called, for example, an interface circuit, a communication unit, or a communication circuit. Interface 22 inputs data received from the third communication device 3 (for example, mobile device-related data) to the control unit 20. Interface 22 also transmits data from the control unit 20 to the third communication device 3.

[0058] The sensor unit 23 is capable of detecting information relating to the second communication device 2. The sensor unit 23 has at least one sensor capable of detecting information relating to the second communication device 2. The at least one sensor includes, for example, a camera 230 that takes pictures of the area around the second communication device 2. The camera 230 may take video or still images. The camera 230 generates camera image data representing a camera image of the area around the second communication device 2 and outputs it to the control unit 20. The camera image data generated by the camera 230 may be video or still image data. The second communication device 2, which has a communication function with the camera 230, can be called, for example, a network camera.

[0059] The control unit 20 can comprehensively manage the operation of the second communication device 2 by controlling other components of the second communication device 2. The control unit 20 can also be described as a processing unit that performs various processes. The control unit 20 can also be described as a control circuit or processing circuit. The control unit 20 includes, for example, at least one processor. The at least one processor included in the control unit 20 may include a CPU.

[0060] The configuration of the memory unit 21 may be the same as that of the memory unit 11 of the server 1. The non-volatile memory of the memory unit 11 stores, for example, a program 21a for controlling the second communication device 2. Various functions of the control unit 20 are realized, for example, by the CPU of the control unit 20 executing the program 21a. Note that the configuration of the memory unit 21 may differ from that of the memory unit 11.

[0061] When the control unit 20 instructs the interface 22 to transmit data to be transmitted, it also instructs the interface 22 to transmit the identification information of the second communication device 2 along with the data to be transmitted. The transmission signal sent by the second communication device 2 includes the identification information of that second communication device 2. Therefore, the server 1 and the third communication device 3 can identify which of the multiple second communication devices 2 the received data originated from. Hereafter, the identification information of the second communication device 2 may be referred to as the second identification information.

[0062] The configuration of the second communication device 2 is not limited to the above example. For example, the control unit 20 may include at least one processor, which may include multiple CPUs or at least one DSP. Also, all or some of the functions of the control unit 20 may be implemented by hardware circuits that do not require software to implement those functions. The storage unit 21 may include, for example, a small hard disk drive and an SSD. The sensor unit 23 may include at least one sensor other than the camera 230. For example, at least one sensor may include a microphone that detects sounds around the second communication device 2. The microphone outputs sound data representing the sounds around the second communication device 2. Also, at least one sensor may include a distance measuring sensor that detects the distance to objects around the second communication device 2. The distance measuring sensor may be a LiDAR. LiDAR is an abbreviation for Light Detection And Ranging. The LiDAR outputs point cloud data representing the distance to objects around the second communication device 2.

[0063] <Example of configuration of the third communication device> Figure 6 is a schematic diagram showing an example configuration of the third communication device 3. As shown in Figure 6, the third communication device 3 includes, for example, a control unit 30, a storage unit 31, an interface 32, and a sensor unit 33. The third communication device 3 is mounted on a mobile body 300. The third communication device 3 is, for example, a computer device.

[0064] Interface 32 is capable of wireless communication with the second communication device 2 in accordance with the second communication standard. Interface 32 is also capable of wireless communication in accordance with the first communication standard. Interface 32 of the third communication device 3 is capable of wireless communication with other third communication devices 3 and the server 1 in accordance with the first communication standard. Interface 32 can also be called, for example, an interface circuit, a communication unit, or a communication circuit. Interface 32 inputs received data to the control unit 20. Interface 32 also transmits data from the control unit 30.

[0065] The sensor unit 33 is capable of detecting information relating to the third communication device 3. The sensor unit 33 of the third communication device 3 is capable of detecting information relating to the mobile body 300 on which the third communication device 3 is installed.

[0066] The sensor unit 33 has at least one sensor capable of detecting information about the moving object 300. The at least one sensor includes, for example, a position sensor 330, an inertial sensor 331, a temperature sensor 332, and a microphone 333.

[0067] The position sensor 330 can detect the position of the moving object 300. It can also be said that the position sensor 330 detects the position of the third communication device 3. The position sensor 330 can acquire position data representing the position of the moving object 300 based on received signals, for example, from GNSS satellites (e.g., GPS satellites). GNSS is an abbreviation for Global Navigation Satellite System. GPS is an abbreviation for Global Positioning System.

[0068] The inertial sensor 331 is, for example, a 6-axis sensor. The inertial sensor 331 comprises, for example, a 3-axis accelerometer and a 3-axis gyroscope. The inertial sensor 331 is also called, for example, a 6DoF sensor. DoF is an abbreviation for Degree of Freedom. The accelerometer of the inertial sensor 331 is capable of detecting the acceleration acting on the moving object 300. The gyroscope of the inertial sensor 331 is capable of detecting the rotation angle of the moving object 300. The inertial sensor 331 outputs 6-axis data representing the detected acceleration and rotational speed.

[0069] The temperature sensor 332 is capable of detecting the temperature of the moving object 300. If the moving object 300 is an animal, the temperature sensor 332 can detect the animal's body temperature. The temperature sensor 332 outputs temperature data representing the detected temperature.

[0070] Microphone 333 can detect sounds around the mobile object 300. It can also be said that microphone 333 can detect sounds around the third communication device 3. The sounds around the mobile object 300 include sounds generated by the mobile object 300 itself. If the mobile object 300 is an animal, microphone 333 can detect sounds emitted by the animal (e.g., vocalizations). Microphone 333 outputs sound data representing the detected sounds.

[0071] Hereafter, when there is no need to distinguish between the position data, 6-axis data, temperature data, and sound data obtained by the sensor unit 33, they may each be referred to as third sensor data. Third sensor data can also be described as data related to moving objects.

[0072] The control unit 30 can comprehensively manage the operation of the third communication device 3 by controlling other components of the third communication device 3. The control unit 30 can also be described as a processing unit that performs various processes. The control unit 30 can also be described as a control circuit or processing circuit. The control unit 30 includes, for example, at least one processor. The at least one processor included in the control unit 30 may include a CPU.

[0073] The configuration of the memory unit 31 may be the same as that of the memory unit 11 of the server 1. The non-volatile memory of the memory unit 31 stores, for example, a program 31a for controlling the third communication device 3. Various functions of the control unit 30 are realized, for example, by the CPU of the control unit 30 executing the program 31a. Note that the configuration of the memory unit 31 may differ from that of the memory unit 11.

[0074] If the position sensor 330 is unable to receive signals from GNSS satellites, the control unit 30 may correct the position data obtained by the position sensor 330 based on the 6-axis data obtained by the inertial sensor 331. This allows the third communication device 3 to obtain position data that appropriately represents the position of the moving object 300, even if the position sensor 330 is unable to receive signals from GNSS satellites, such as when the moving object 300 is hidden behind an object. In the following description, the position data also includes position data corrected based on the 6-axis data.

[0075] When the control unit 30 instructs the interface 32 to transmit data to be transmitted, it instructs the interface 32 to transmit the identification information of the third communication device 3 along with the data to be transmitted. The transmission signal sent by the third communication device 3 includes the identification information of the third communication device 3. Therefore, the server 1 and the second communication device 2 can identify which of the multiple third communication devices 3 the received data originated from. Hereafter, the identification information of the third communication device 3 may be referred to as the third identification information. The third identification information can also be said to be the identification information of the mobile device 300.

[0076] The configuration of the third communication device 3 is not limited to the above example. For example, the control unit 30 may include at least one processor, or at least one DSP. Also, all or some of the functions of the control unit 30 may be implemented by hardware circuits that do not require software to implement those functions. The storage unit 31 may include, for example, a small hard disk drive and an SSD. The sensor unit 33 may include sensors other than the position sensor 330, inertial sensor 331, temperature sensor 332 and microphone 333. For example, the sensor unit 33 may include a humidity sensor, a camera, or a distance measuring sensor such as LiDAR. Also, for example, if the mobile body 300 on which the third communication device 3 is mounted is an animal such as livestock, the third communication device 3 may be a tag-type device attached to the animal.

[0077] <An example of how to connect the third communication device to the second communication device> Figure 7 is a flowchart illustrating an example of the connection destination determination process by which the third communication device 3 determines the second communication device 2 to which it will connect. The connection of the third communication device 3 to the second communication device 2 can be described as the connection of the third communication device 3 to the short-range network 200, or as the third communication device 3 joining or participating in the short-range network 200. Hereafter, the transmission signal of the second communication device 2 may be referred to as the second transmission signal. The third communication device 3 being described may be referred to as the target third communication device 3. The target third communication device 3 can also be referred to as the third communication device 3 of interest. The mobile unit 300 on which the target third communication device 3 is mounted may be referred to as the target mobile unit 300. The target mobile unit 300 can also be referred to as the mobile unit 300 being described.

[0078] In the connection destination determination process, as shown in Figure 7, first in step s1, the control unit 30 of the target third communication device 3 acquires the RSSI of the second transmission signal received by the interface 32. RSSI is an abbreviation for Received Signal Strength Indicator. RSSI is information that indicates the received signal strength (in other words, the received signal level).

[0079] Next, in step s2, the control unit 30 determines whether or not to change the connected second communication device 2 based on the RSSI obtained in step s1. For example, if the communication areas 120 of multiple second communication devices 2 partially overlap, the RSSIs of the second transmission signals from multiple second communication devices 2 may be obtained in step s1. In this case, the control unit 30 identifies the largest RSSI among the multiple RSSIs obtained in step s1. Next, the control unit 30 determines whether or not the second communication device 2 that transmits the second transmission signal showing the largest RSSI is the second communication device 2 that is currently connected. If the second communication device 2 that transmits the second transmission signal showing the largest RSSI is the second communication device 2 that is currently connected, the control unit 30 decides not to change the connected second communication device 2 (NO in step s2). Then, the target third communication device 3 maintains the connection to the second communication device 2 that is currently connected (step s6).

[0080] On the other hand, if the second communication device 2 that transmits the second transmission signal indicating the maximum RSSI is not the second communication device 2 that is currently connected, the control unit 30 decides to change the second communication device 2 to be connected to to the second communication device 2 that transmits the second transmission signal indicating the maximum RSSI (YES in step s2). Then, in step s3, the target third communication device 3 checks with the target second communication device 2 (i.e., the second communication device 2 that transmits the second transmission signal indicating the maximum RSSI) to see if it is possible to connect to that second communication device 2.

[0081] In step s3, the control unit 30 generates request data requesting a connection to the target second communication device 2. The control unit 30 then causes interface 32 to transmit the generated request data to the target second communication device 2. Upon receiving the request data from the target third communication device 3, the second communication device 2 transmits permission data to the target third communication device 3 if it permits the target third communication device 3 to connect to the second communication device 2. On the other hand, if the second communication device 2 does not permit the target third communication device 3 to connect to the second communication device 2, it transmits permission data to the target third communication device 3. When interface 32 receives the permission data, the control unit 30 determines that it is possible to connect to the target second communication device 2 (YES in step s3), and step s4 is executed. On the other hand, if interface 32 receives unauthorized data, the control unit 30 determines that it cannot connect to the target second communication device 2 (NO in step s3), and the target third communication device 3 maintains its connection to the second communication device 2 (step s6).

[0082] In step s4, the control unit 30 generates disconnection notification data to notify the disconnection of the connection. The control unit 30 then causes the generated disconnection notification data to be sent to the second communication device 2 connected to interface 32. Next, in step s5, the target third communication device 3 connects to the new second communication device 2. This changes the second communication device 2 to which the target third communication device 3 is connected. The target third communication device 3 also sends the second identification information of the new second communication device 2 and the third identification information of the target third communication device 3 to the server 1. The server 1 stores the second identification information and third identification information received from the target third communication device 3 in the storage unit 11, associating them with each other. This allows the server 1 to identify the second communication device 2 to which each third communication device 3 is connected.

[0083] In step s1, if only the RSSI of the second transmission signal from one second communication device 2 is obtained, the control unit 30 determines whether the second communication device 2 that transmits the second transmission signal indicating the RSSI obtained in step s1 is the second communication device 2 that is currently connected. If the second communication device 2 that transmits the second transmission signal indicating the RSSI obtained in step s1 is the second communication device 2 that is currently connected, the control unit 30 decides not to change the second communication device 2 to be connected (NO in step s2). On the other hand, if the second communication device 2 that transmits the second transmission signal indicating the RSSI obtained in step s1 is not the second communication device 2 that is currently connected, the control unit 30 decides to change the second communication device 2 to be connected to the second communication device 2 that transmits the second transmission signal indicating the RSSI obtained in step s1 (YES in step s2). Thereafter, the target third communication device 3 operates in the same manner as described above.

[0084] The target third communication device 3 may periodically and repeatedly perform the connection destination determination process shown in Figure 7. Alternatively, the target third communication device 3 may perform the connection destination determination process when the target mobile body 300 (i.e., the mobile body 300 on which the target third communication device 3 is mounted) starts moving and then stops. The control unit 30 of the target third communication device 3 can identify the movement and stopping of the target mobile body 300 based on the position data from the position sensor 330.

[0085] Furthermore, if the communication areas 120 of multiple second communication devices 2 partially overlap, animals such as livestock, which act as mobile entities 300, may wander around the boundaries of these multiple communication areas 120. In this case, the second communication device 2 to which the third communication device 3 mounted on the animal is connected may change frequently.

[0086] Therefore, the third communication device 3 may execute the connection destination determination process shown in Figure 7 only if the connection time with the currently connected second communication device 2 has been elapsed for a certain period of time (for example, 1 minute) or longer. This makes it less likely that the second communication device 2 to which the third communication device 3 is connected will change frequently.

[0087] <Example of communication system operation> The operation of communication system 5 is described below. Here, the data relay at the third communication device 3 will not be explained in detail, but will be explained in detail later.

[0088] The third communication device 3 repeatedly transmits, for example, the position data of the position sensor 330 along with the third identification information to the server 1. The position data transmitted by the third communication device 3 may reach the server 1 directly, or it may reach the server 1 via another third communication device 3. The third communication device 3 may also repeatedly transmit the position data to the server 1 at regular intervals. Furthermore, the third communication device 3 may transmit the position data to the server 1 when the mobile body 300 on which the third communication device 3 is mounted starts moving and then stops.

[0089] Server 1 stores the location data and third identification information received from each third communication device 3 in the storage unit 11, associating them with each other. This allows Server 1 to manage the current and past locations of the mobile body 300 on which each third communication device 3 is installed within the monitoring area 500. Server 1 manages the location history (in other words, the location data history) of each mobile body 300 within the monitoring area 500. It can also be said that Server 1 manages the location history of each third communication device 3. It can also be said that Server 1 monitors the location of each mobile body 300 within the monitoring area 500, or it can be said that Server 1 monitors the location of each third communication device 3 within the monitoring area 500.

[0090] Furthermore, for each second communication device 2, Server 1 stores in the storage unit 11 the second identification information of the second communication device 2, location data representing the location of the second communication device 2, and communication area data representing the communication area 120 of the second communication device 2, in association with each other. Server 1 recognizes the location and communication area 120 of each second communication device 2. Hereafter, the location data of the second communication device 2 may be referred to as the second location data. Also, the location data of the third communication device 3, in other words, the location data of the mobile body 300, may be referred to as the third location data or mobile body location data.

[0091] The third communication device 3 repeatedly transmits the position data of the position sensor 330 (in other words, the third position data) along with the third identification information to the connected second communication device 2. The third communication device 3 may also transmit the third position data to the connected second communication device 2 during the connection destination determination process described above (for example, after step s5 and after step s6). In addition, the third communication device 3 may perform a process to transmit the third position data to the connected second communication device 2 separately from the connection destination change process.

[0092] The second communication device 2 stores in the storage unit 21, associating the third location data (in other words, mobile location data) and third identification information received from each third communication device 3 located within the communication area 120 with each other. It can also be said that the second communication device 2 stores in the storage unit 21, associating the third location data and third identification information received from each third communication device 3 connected to it with each other. The second communication device 2 manages the location history (in other words, the history of mobile location data) of the mobile body 300 on which each third communication device 3 located within the communication area 120 is equipped. It can also be said that the second communication device 2 manages the location history of each mobile body 300 located within the communication area 120. It can also be said that the second communication device 2 monitors the location of each mobile body 300 located within the communication area 120.

[0093] The third communication device 3 transmits the temperature data from the temperature sensor 332 and the sound data from the microphone 333, along with the third identification information, to the connected second communication device 2. The third communication device 3 continuously or periodically transmits the temperature data and sound data to the connected second communication device 2.

[0094] Furthermore, the third communication device 3 may transmit temperature data to the connected second communication device 2 only if the temperature represented by the temperature data is above a threshold. Also, the third communication device 3 may transmit audio data to the connected second communication device 2 only if the volume of the sound represented by the sound data is above a threshold.

[0095] The second communication device 2 stores temperature data, sound data, and third identification information received from each third communication device 3 located within the communication area 120 in the storage unit 21, associating them with each other.

[0096] The control unit 20 of the second communication device 2 may determine the state of the target mobile object 300 based on at least one of the temperature data and sound data of the target third communication device 3. For example, the control unit 20 may determine that the target mobile object 300 is abnormal if the temperature indicated by the temperature data of the target third communication device 3 remains above a threshold for a predetermined period of time or longer. If the target mobile object 300 is an animal such as livestock, the control unit 20 can determine that the animal is abnormal if its body temperature remains high for a predetermined period of time (e.g., one day) or longer. The control unit 20 may also determine that the target mobile object 300 is abnormal if the rate of change per unit time of the temperature indicated by the temperature data of the target third communication device 3 is above a threshold. If the target mobile object 300 is an animal such as livestock, the control unit 20 can determine that the animal is abnormal if its body temperature changes rapidly (e.g., rapidly changes by 1°C or more). The control unit 20 may also determine that the target mobile object 300 is abnormal if the rate of change per unit time of the volume of sound represented by the sound data of the target third communication device 3 is above a threshold. For example, if the target moving object 300 is an animal such as livestock, the control unit 20 can determine that the animal is abnormal if the animal's cries suddenly become louder.

[0097] The control unit 20 stores in the storage unit 21 the determination result data indicating the status of the target mobile object 300 (for example, whether the mobile object 300 is abnormal or not) and the third identification information of the target third communication device 3, associating them with each other.

[0098] The control unit 20 may transmit the determination result data of the target mobile object 300, along with the third identification information of the target third communication device 3, to the server 1 via the interface 22. The determination result data transmitted by the second communication device 2 reaches the server 1 via at least one third communication device 3.

[0099] Server 1 stores the judgment result data and third identification information received from the target third communication device in the storage unit 11, associating them with each other. This allows Server 1 to manage the history of judgment results for the state of each mobile unit 300 (in other words, the history of the state of each mobile unit 300). It can also be said that Server 1 can individually monitor the state of each mobile unit 300. Server 1 may also display the judgment result data stored in the storage unit 11.

[0100] The control unit 20 of the second communication device 2 may determine whether the camera 230 can photograph each mobile object 300 located within the communication area 120. In this case, the control unit 20 may determine, one by one, whether the camera 230 can photograph each mobile object 300 located within the communication area 120.

[0101] When the control unit 20 determines whether the camera 230 can photograph the target mobile object 300 mounted on the target third communication device 3 within the communication area 120, it obtains the latest third position data associated with the third identification information of the target mobile object 300 from the storage unit 21. Next, the control unit 20 causes the camera 230 to photograph the area around the position indicated by the obtained third position data. Next, the control unit 20 identifies the third identification information of each mobile object 00 from the camera image obtained by the camera 230.

[0102] Here, for example, each mobile body 300 is equipped with a display unit that lights up in a lighting pattern corresponding to the third identification information of the mobile body 300. The display unit may have, for example, multiple light-emitting diodes. The display unit may be provided in the third communication device 3, or it may be provided separately from the third communication device 3. The storage unit 21 of the second communication device 2 associates the third identification information and lighting pattern of each mobile body 300 within the monitoring area 500 with each other. Based on the camera image data from the camera 230, the control unit 20 identifies the lighting pattern of each mobile body 300 that is captured in the camera image data. The control unit 20 then obtains the third identification information corresponding to the identified lighting pattern from the storage unit 21. As a result, the control unit 20 can identify the third identification information of each mobile body 300 from the mobile body 00 captured in the camera image.

[0103] The control unit 20 determines that the camera 230 can photograph the target mobile object 300 if the identified third identification information includes information that matches the third identification information of the target mobile object 300. On the other hand, the control unit 20 determines that the camera 230 cannot photograph the target mobile object 300 if the identified third identification information does not include information that matches the third identification information of the target mobile object 300.

[0104] The method by which the control unit 20 acquires the third identification information of the moving object 300 captured in the camera image is not limited to the above example. For example, the moving object 300 may be fitted with a suspendable tag or the like, which may display a barcode representing the third identification information of the moving object 300. The barcode may be a one-dimensional barcode or a two-dimensional barcode. Based on the camera image data, the control unit 20 can recognize the barcode of each moving object 300 captured in the camera image represented by the camera image data and acquire the third identification information of the moving object 300.

[0105] Furthermore, the mobile body 300 may be fitted with a suspendable tag or the like, displaying a symbol indicating the third identification information. In this case, the control unit 20 can acquire the third identification information by image recognition of the symbol displayed on each mobile body 300 captured in the camera image.

[0106] The second communication device 2 may notify the server 1 of an alert when it determines that the camera 230 cannot photograph the target mobile object 300 within the communication area 120. For example, when the control unit 20 determines that the camera 230 cannot photograph the target mobile object 300 within the communication area 120, it generates alert data indicating that the camera 230 cannot photograph the target mobile object 300. The control unit 20 then transmits the generated alert data and the third identification information of the target mobile object 300 to the server 1 through the interface 22. The server 1 may store the received alert data and the third identification information in the storage unit 11 in correspondence with each other.

[0107] The control unit 20 may associate the third identification information of a mobile object 300 within the communication area 120, stored in the memory unit 21, with an image that primarily shows the mobile object 300. In other words, the control unit 20 may associate the third identification information of a mobile object 300 within the communication area 120, stored in the memory unit 21, with image data representing an image that primarily shows the mobile object 300. Hereafter, an image that primarily shows the mobile object 300 may be referred to as a mobile object image. Also, image data representing a mobile object image may be referred to as mobile object image data. A mobile object image may be a video or a still image. That is, mobile object image data may be video data or still image data.

[0108] Here, when the third identification information of a certain mobile object 300 captured in the camera image, acquired by the control unit 20 as described above, matches the third identification information of a target mobile object 300 within the communication area 120, the certain mobile object 300 captured in the camera image is the target mobile object 300. The control unit 20 may also use image recognition to extract a portion of the camera image containing the target mobile object 300, and use the extracted portion as the mobile object image in which the target mobile object 300 is mainly captured. Alternatively, the control unit 20 may use the zoom of the camera 230 to enlarge and photograph the target mobile object 300, and use the resulting camera image as the mobile object image in which the target mobile object 300 is mainly captured. In the memory unit 21, for each mobile object 300 within the communication area 120 (in other words, each mobile object 300 connected to the second communication device 2), the third identification information of the mobile object 300, the location data of the mobile object 300, the temperature data and sound data related to the mobile object 300, the determination result data of the mobile object 300, and mobile object image data representing the mobile object image in which the mobile object 300 is captured are associated with each other. The mobile object image data can also be said to be mobile object-related data.

[0109] Hereafter, a moving image containing the target moving object 300 may be referred to as the target moving object image. Similarly, the moving object image data representing the target moving object image may also be referred to as the target moving object image data.

[0110] The control unit 20 may determine the state of the target mobile object 300 based on the target mobile object image data. For example, the control unit 20 may determine whether the target mobile object 300 is abnormal based on the target mobile object image data. Also, if the mobile object 300 is livestock such as a cow, the control unit 20 may determine whether the livestock, which is the target mobile object 300, is overlapping with other livestock based on the target mobile object image data. If the control unit 20 determines that the livestock, which is the target mobile object 300, is overlapping with other livestock, it may determine that the livestock, which is the target mobile object 300, may be in heat. Also, if the mobile object 300 is livestock such as a cow, the control unit 20 may determine whether the livestock, which is the target mobile object 300, is close to giving birth, is giving birth, is in heat, or is mating based on the target mobile object image data.

[0111] The control unit 20 may determine the state of the target mobile object 300 based on the target mobile object image data and at least one of the temperature data and sound data related to the target mobile object 300. For example, the control unit 20 may determine whether the target mobile object 300 is abnormal based on the target mobile object image data and at least one of the temperature data and sound data related to the target mobile object 300. Also, if the mobile object 300 is livestock such as a cow, the control unit 20 may determine whether the livestock, which is the target mobile object 300, is close to giving birth, is giving birth, is in estrus, or is mating, based on the target mobile object image data and at least one of the temperature data and sound data related to the target mobile object 300.

[0112] The control unit 20 may use a machine learning model when determining the state of the target moving object 300. In this case, the control unit 20 may have a machine learning model that determines the state of the target moving object 300 based on at least one of the target moving object image data, temperature data related to the target moving object 300, and sound data related to the target moving object 300, and outputs the determination result.

[0113] The control unit 20 may repeatedly perform an acquisition and determination process for each mobile object 300 in the communication area 120, sequentially, to acquire mobile object image data of the mobile object 300 and to determine the state of the mobile object 300 based on the acquired mobile object image data.

[0114] The control unit 20 may determine whether the target mobile object 300 is a cause for concern based on the determination result of the state of the target mobile object 300. For example, the control unit 20 may determine whether each mobile object 300 in the communication area 120 is a cause for concern in turn. For example, the control unit 20 may determine that the target mobile object 300 is a cause for concern when it determines that the target mobile object 300 is abnormal. Also, if the mobile object 300 is livestock such as a cow, the control unit 20 may determine that the target mobile object 300 is a cause for concern when it determines that the livestock as the target mobile object 300 is overlapping with other livestock. Also, the control unit 20 may determine that the target mobile object 300 is a cause for concern when it determines that the livestock as the target mobile object 300 is close to giving birth, giving birth, in heat, or mating.

[0115] If the control unit 20 determines that the target moving object 300 is a target requiring attention, it may have the camera 230 continuously photograph the target moving object 300 for a predetermined time (for example, 1 hour). At this time, the camera 230 may zoom in on the target moving object 300 and acquire target moving object image data representing the image of the target moving object (in other words, moving image data representing a video in which the target moving object is captured). The target moving object image data obtained by the camera 230 continuously photographing the target moving object 300 for a predetermined time is stored in the storage unit 21 in association with the third identification information of the target moving object 300.

[0116] The second communication device 2 may transmit image data to the server 1. For example, when the control unit 20 determines that the target moving object 300 is a target of attention, it may transmit image data of the moving object 300 to the server 1 via the interface 22.

[0117] Here, the timing at which the control unit 20 determines that the target mobile object 300 is a cause for concern is used as the reference timing. For example, if the control unit 20 determines that the target mobile object 300 is a cause for concern when it is abnormal, then the reference timing can be said to be the timing at which the control unit 20 determines that the target mobile object 300 is abnormal.

[0118] Furthermore, the first timing is defined as the timing after a first predetermined time has elapsed from the reference timing. The first predetermined time may be, for example, 1 minute or more and 5 minutes or less. Also, the second timing is defined as the timing two predetermined times before the reference timing. The second predetermined time may be, for example, 1 minute or more and 5 minutes or less.

[0119] If the second communication device 2 determines that the target mobile object 300 is of concern, it may transmit to the server 1 in real time the target mobile object image data (also called the first target mobile object image data) obtained by the camera 230 photographing the target mobile object 300 from the reference timing to the first timing. If the second communication device 2 determines that the target mobile object 300 is of concern, it may also transmit to the server 1 the target mobile object image data (also called the second target mobile object image data) obtained by the camera 230 photographing the target mobile object 300 from the second timing to the reference timing. If the second communication device 2 determines that the target mobile object 300 is of concern, it may also transmit to the server 1 the target mobile object image data (also called the third target mobile object image data) obtained by the camera 230 photographing the target mobile object 300 from the second timing to the first timing. Furthermore, the second communication device 2 may transmit to the server 1 the target mobile object image data (also called the fourth target mobile object image data) obtained before the second timing (for example, one hour or several hours before the reference timing).

[0120] If the second communication device 2 determines that the target mobile object 300 is abnormal and requires attention, it may decide which of the first target mobile object image data, second target mobile object image data, third target mobile object image data, and fourth target mobile object image data to send to the server 1, depending on the nature of the abnormality of the target mobile object 300.

[0121] The second communication device 2 may transmit either temperature data or sound data to the server 1. For example, when the control unit 20 determines that the target mobile object 300 is a target of attention, it may transmit at least one of the temperature data and sound data relating to the target mobile object 300 to the server 1 through the interface 22.

[0122] If the second communication device 2 determines that the target mobile object 300 is a cause for concern, it may transmit at least one of the temperature data and sound data obtained between the reference timing and the first timing in real time to the server 1. Furthermore, if the second communication device 2 determines that the target mobile object 300 is a cause for concern, it may transmit at least one of the temperature data and sound data obtained between the second timing and the reference timing to the server 1. Furthermore, if the second communication device 2 determines that the target mobile object 300 is a cause for concern, it may transmit at least one of the temperature data and sound data obtained between the second timing and the first timing to the server 1. Also, the second communication device 2 may transmit at least one of the temperature data and sound data obtained before the second timing (for example, one hour or several hours before the reference timing) to the server 1. If the second communication device 2 determines that the target mobile object 300 is a cause for concern due to an abnormality, it may determine, similar to the case of transmitting target mobile object image data, which period of temperature data and sound data to transmit to the server 1, depending on the nature of the abnormality of the target mobile object 300.

[0123] The second communication device 2 may use a machine learning model such as an autoencoder to extract features from the camera image and the moving object image, and transmit the feature data representing the extracted features to the server 1.

[0124] The third communication device 3 may transmit temperature data obtained from the temperature sensor 332 to the server 1, or it may transmit sound data obtained from the microphone 333 to the server 1. The third communication device 3 may transmit temperature data to the server 1 only if the temperature represented by the temperature data is above a threshold. The third communication device 3 may also transmit sound data to the server 1 only if the volume of the sound represented by the sound data is above a threshold.

[0125] Server 1 may determine the state of the target mobile object 300 based on at least one of the temperature data and sound data related to the target mobile object 300 received from the third communication device 3. Server 1 may also receive camera image data or mobile object image data from the second communication device 2 and determine the state of the mobile object 300 captured in the received camera image data or mobile object image data. The method for determining the state of the mobile object 300 at Server 1 may be the same as, or different from, the method for determining the state of the mobile object 300 at the second communication device 2.

[0126] If the sensor unit 23 of the second communication device 2 has sensors other than the camera 230, the second communication device 2 may transmit output data from the sensors other than the camera 230 to the server 1. For example, if the sensor unit 23 has a LiDAR, the second communication device 2 may transmit point cloud data output by the LiDAR to the server 1. Also, if the sensor unit 23 is equipped with a microphone, the second communication device 2 may transmit sound data output by the microphone to the server 1.

[0127] If the sensor unit 33 of the third communication device 3 is equipped with a camera, the third communication device 3 may transmit camera image data obtained from the camera to the connected second communication device 2. The second communication device 2 may then transmit the camera image data received from the third communication device 3 to the server 1.

[0128] The second communication device 2 does not need to determine the state of the mobile body 300. The third communication device 3 does not need to transmit at least one of the position data, temperature data, and sound data obtained by the sensor unit 33 to the second communication device 2.

[0129] <Regarding data relay at the third communication device> Regarding Wi-Fi HaLow-compliant communication within Japan, Japanese law stipulates a limit on the transmission time per unit of time. Specifically, Japanese law stipulates that the transmission time per hour must be less than or equal to the limit time (specifically, 6 minutes). This limit is sometimes called the 10% duty cycle limit. The third communication device 3 and server 1 communicate in accordance with Wi-Fi HaLow so that the transmission time per hour is 10% or less.

[0130] Communication devices that communicate in accordance with Wi-Fi HaLow, such as the third communication device 3 and server 1, have spread mode and burst mode as transmission modes. In spread mode, the communication device satisfies the 10% duty cycle limit by repeatedly transmitting one packet at a cycle 10 times the transmission time of one packet. On the other hand, in burst mode, the communication device can transmit multiple packets continuously within the range that satisfies the 10% duty cycle limit.

[0131] Furthermore, when the third communication device 3 communicates with the second communication device 2 in accordance with Wi-Fi 6, there are no restrictions on transmission time per unit time, such as the 10% duty cycle limit, under Japanese law. The same applies when the second communication device 2 communicates with the third communication device 3 in accordance with Wi-Fi 6.

[0132] Thus, the third communication device 3 has a limit on the transmission time per unit time (i.e., a 10% duty cycle limit) when communicating with other third communication devices 3 and server 1. For this reason, depending on its own communication status, the third communication device 3 may take time to relay large amounts of data (in other words, data with a large data volume) that the second communication device 2 sends to server 1. On the other hand, the third communication device 3 is likely to be able to relay small amounts of data (in other words, data with a large data volume) that the second communication device 2 sends to server 1 very quickly.

[0133] In this example, Server 1 determines multiple relay routes for relaying large amounts of data across multiple Third Communication Devices 3, based on a 10% duty cycle limit. Second Communication Device 2 distributes and relays the large amounts of data destined for Server 1 across the multiple relay routes determined by Server 1. This shortens the time it takes for the large amounts of data sent by Second Communication Device 2 to Server 1 to be relayed by the Third Communication Devices 3 and reach Server 1. Thus, the communication quality of the communication system 5 is improved. Hereafter, the relay route for relaying large amounts of data may be referred to as the relay route (large). Data relayed on the relay route (large) is relayed by at least one of the Third Communication Devices 3 that constitute the relay route (large).

[0134] On the other hand, Server 1 determines relay routes (also called relay routes (small)) that relay small-capacity data through multiple third communication devices 3, without being limited by a 10% duty cycle. Small-capacity data relayed on relay routes (small) is relayed by at least one third communication device 3 that constitutes the relay route (small).

[0135] Here, the mesh network (in this example, a mesh network compliant with EasyMesh) on which the network 100, consisting of server 1 and multiple third communication devices 3, functions is composed of a communication device called a controller, a communication device called an agent, and a communication device called a station. In a mesh network, the controller can be said to be, for example, a parent access point or root access point, an agent can be said to be, for example, a child access point, and a station can be said to be, for example, a terminal device. The controller manages the operation of the entire mesh network. In a mesh network, data between a station and a controller is relayed by at least one agent. An agent can be said to be a relay device.

[0136] The controller determines the route (also called the mesh route) through which data travels in the mesh network, according to a predetermined protocol (in other words, a predetermined standard). That is, the controller determines, according to a predetermined protocol, which communication devices in the mesh network the data between the station and the controller passes through. The controller determines the mesh route based on the signal strength of the communication signal between the controller and the agent, the congestion level of the mesh network, and the number of devices connected to the agent.

[0137] When network 100 functions as a mesh network, server 1 acts as the controller, and third communication devices 3 function as either stations or agents. Server 1 determines for each third communication device 3 whether it functions as a station or an agent.

[0138] In this example, when small amounts of data pass through network 100, server 1 makes network 100 function as a mesh network. That is, server 1 forms a mesh network with multiple third communication devices 3 and transmits small amounts of data through the mesh network. Hereafter, network 100 that functions as a mesh network may be referred to as mesh network 100.

[0139] In the mesh network 100, the server 1, acting as a controller, determines mesh routes for transmitting small-capacity data according to the mesh network 100 protocol. As a result, the server 1 determines relay routes (small) for relaying small-capacity data among multiple third communication devices 3, without being limited by a 10% duty cycle.

[0140] When network 100 transmits large amounts of data (in other words, when relaying large amounts of data to the third communication device 3), server 1 does not make network 100 function as a mesh network, but instead determines the relay route (large) based on a 10% duty cycle limit according to a protocol different from the mesh network protocol.

[0141] In this example, large data refers to data of 10 megabytes or more. Large data includes, for example, image data, sound data representing long periods of sound, point cloud data, and feature data. Small data refers to, for example, data of less than 10 megabytes. Small-to-large data includes, for example, location data, temperature data, sound data representing short periods of sound, and judgment result data.

[0142] In this example, small amounts of data are exchanged between the third communication device 3 and the server 1, but large amounts of data are not. When the target third communication device 3 sends small amounts of data to the server 1, the target third communication device 3 becomes a station, and the other third communication devices 3 become agents, and a mesh route is determined for transmitting the small amounts of data sent by the target third communication device 3. Examples of small amounts of data that the third communication device 3 sends to the server 1 include location data, temperature data, and sound data representing short periods of sound. When the server 1 sends small amounts of data to the target third communication device 3, the target third communication device 3 becomes a station, and the other third communication devices 3 become agents, and a mesh route is determined for transmitting the small amounts of data sent by the server 1.

[0143] The small data that the second communication device 2 sends to the server 1 is transmitted via the mesh network 100 and reaches the server 1. The second communication device 2 sends the small data for the server 1 to the third communication device 3, which is located within the communication area 120 as a station. The third communication device 3, as a station, sends the small data from the second communication device 2 to the server 1 through the third communication device 3, which is acting as an agent.

[0144] In this example, the third communication device 3 can directly transmit large amounts of data to the connected second communication device 2, but it cannot transmit it to the second communication device 2 through other third communication devices 3. Large amounts of data, such as image data, can be exchanged between the second communication device 2 and the third communication device 3 via Wi-Fi 6 compliant communication. On the other hand, the third communication device 3 can directly transmit small amounts of data to the connected second communication device 2, as well as transmit it to the second communication device 2 through other third communication devices 3 (in other words, through the network 100). When the third communication device 3 transmits small amounts of data to the second communication device 2 through other third communication devices 3, the small amounts of data are transmitted between that third communication device 3 and that other third communication device 3 via the mesh network 100.

[0145] <Regarding the transmission of large amounts of data> The following describes an example of the operation of the communication system 5 when the second communication device 2 transmits large amounts of data to the server 1. Examples of large amounts of data that the second communication device 2 transmits to the server 1 include camera image data, mobile image data, sound data, point cloud data, and feature data. The operation of the communication system 5 when the server 1 transmits large amounts of data to the second communication device 2 is the same as described below. Hereafter, the second communication device 2 that is the subject of this description may be referred to as the target second communication device 2. Also, the large amounts of data that the target second communication device 2 transmits may be referred to as the target large amounts of data.

[0146] Figure 8 is a schematic diagram showing an example of the operation of the communication system 5 when the second communication device 2 transmits a large amount of data to the server 1. In the communication system 5, for each second communication device 2, when the second communication device 2 transmits a large amount of data to the server 1, the series of processes shown in Figure 8 are executed.

[0147] As shown in Figure 8, in step s21, the target second communication device 2 sends start notification data to the server 1 to notify the start of transmission of the target large-capacity data (e.g., mobile image data). The start notification data is small-capacity data and is transmitted to the server 1 via the mesh network 100.

[0148] When the control unit 10 of the server 1 receives start notification data from the target second communication device 2 through at least one third communication device 3, in step s22, it determines a first predetermined number P (in other words, P relay routes) for relaying the target large-capacity data. P is an integer of 2 or more. As will be described later, the control unit 10 determines the first predetermined number P relay routes based on a 10% duty cycle limit.

[0149] After step s22, in step s23, the control unit 10 removes each third communication device 3 included in the determined first predetermined number P relay routes (large) from the mesh route for subsequent communication of small-capacity data. As a result, each third communication device 3 included in the first predetermined number P relay routes (large) determined in step s22 will no longer be used for transmitting small-capacity data.

[0150] After step s23, in step s24, the control unit 10 generates role notification data representing the role of each third communication device 3 included in the determined first predetermined number P relay routes (large). Then, the control unit 10 transmits the role notification data to each third communication device 3 included in the first predetermined number P relay routes (large) via the interface 12. The role notification data is small-capacity data and is transmitted over the mesh network.

[0151] Here, the relay route (large) consists of a direct communication device 3 and at least one indirect communication device 3. The direct communication device 3 is a third communication device 3 that directly receives large amounts of data from the second communication device 2. In contrast, the indirect communication device 3 is a third communication device 3 that indirectly receives large amounts of data transmitted by the second communication device 2 through other third communication devices 3. The direct communication device 3 can also be said to be the third communication device 3 that first relays large amounts of data in the relay route (large), or the leading third communication device 3. The indirect communication device 3 can also be said to be a third communication device 3 that relays large amounts of data from the direct communication device 3 to the server 1. For example, the direct communication device 3 can be said to correspond to a station in a mesh network, and the indirect communication device 3 can be said to correspond to an agent in a mesh network.

[0152] As will be described later, in step s22, the control unit 10 determines the direct communication device 3 and indirect communication device 3 for each of the first predetermined number P relay routes (large) from a plurality of third communication devices 3 within the monitoring area 500. The role notification data transmitted in step s24 is data indicating whether the third communication device 3 functions as a direct communication device 3 or an indirect notification device 3. The third communication device 3 operates according to the role indicated by the role notification data received from the server 1.

[0153] After step s24, in step s25, the control unit 10 generates route notification data representing the first predetermined number P relay routes (large) that have been determined. The control unit 10 then transmits the generated route notification data to the target second communication device 2 through interface 12. This allows the target second communication device 2 to know the first predetermined number of relay routes (large) that relay the target large-capacity data. The route notification data is small-capacity data and is transmitted to the target second communication device 2 through the mesh network 100.

[0154] Upon receiving the route notification data, the target second communication device 2 transmits the target large-capacity data to the server 1 in step s26. At this time, the target second communication device 2 transmits the large-capacity data to the server 1 by distributing the target large-capacity data to a predetermined number of relay routes (large) represented by the received route notification data and relaying them sequentially.

[0155] In this way, by distributing and relaying large amounts of data across multiple relay routes (large) determined based on a 10% duty cycle limit, the third communication device 3 can more easily transmit large amounts of data while adhering to the 10% duty cycle limit. Therefore, the time it takes for large amounts of data sent from the second communication device 2 to the server 1 to be relayed by the third communication device 3 and reach the server 1 can be shortened. As a result, the communication quality of the communication system 5 is improved.

[0156] Figure 9 is a flowchart showing an example of step s22. In step s22, steps s31 and s32 are executed in order, as shown in Figure 9. In step s31, the control unit 10 determines each direct communication device 3 for a first predetermined number of relay routes (large) that relay large-capacity data from the target second communication device 2. The control unit 10 determines a first predetermined number P (in other words, P devices) of direct communication devices 3. In step s32, the control unit 10 determines each indirect communication device 3 for the first predetermined number P of relay routes (large). That is, for each relay route (large), the control unit 10 determines at least one indirect communication device 3 that relays the target large-capacity data between the direct communication device 3 and the server 1 in that relay route (large). In step s31, a first predetermined number P of direct communication devices 3 that relay the target large-capacity data are determined, and in step s32, for each direct communication device 3, at least one indirect communication device 3 that relays the large-capacity data from the direct communication device to the server 1 is determined, thereby determining a first predetermined number of relay routes (large) that relay the target large-capacity data.

[0157] The control unit 10 determines a first predetermined number P of direct communication devices 3 that directly receive the target large-capacity data from the target second communication device 2, based, for example, on the second location data of the target second communication device 2, the third location data of the third communication device 3, and transmission time-related data regarding the transmission time in Wi-Fi HaLow-compliant communication of the third communication device 3.

[0158] Each third communication device 3 repeatedly transmits transmission time-related data along with third identification information to the server 1. The third communication device 3 may, for example, transmit transmission time-related data to the server 1 periodically. Alternatively, the third communication device 3 may transmit transmission time-related data together with position data from the position sensor 330. The control unit 10 of the server 1 stores the transmission time-related data and third identification information from the third communication devices in the storage unit 11, associating them with each other.

[0159] As described above, for communication compliant with Wi-Fi HaLow, the transmission time per hour is limited to a certain value (specifically, 6 minutes). The third communication device 3 may, for example, use data indicating the remaining time until the transmission time limit for the most recent hour (also called remaining transmission time) for communication compliant with Wi-Fi HaLow as transmission time-related data. Hereafter, the data representing the remaining transmission time may be referred to as remaining transmission time data. If the third communication device 3 has performed Wi-Fi HaLow-compliant transmission for 1 minute in the most recent hour, the remaining transmission time will be 5 minutes, and the remaining transmission time data will show 5 minutes. Hereafter, when simply referring to the transmission time limit, it means the transmission time limit per hour for communication compliant with Wi-Fi HaLow (specifically, 6 minutes).

[0160] Figure 10 is a flowchart showing an example of step s31. In step s31, as shown in Figure 10, step s41 is performed first. In step s41, the control unit 10 selects the third communication device 3 that is closest to the target second communication device 2 within the communication area 120 of the target second communication device 2, based on the second location data and communication area data of the target second communication device 2 stored in the storage unit 11 and the latest third location data of each third communication device 3 stored in the storage unit 11. Hereafter, the third communication device 3 selected in step s41 will be referred to as the selected third communication device 3.

[0161] Next, in step s42, the control unit 10 determines whether the remaining transmission time indicated by the latest remaining transmission time data of the selected third communication device 3 in the storage unit 11 is equal to or greater than a first predetermined value. The first predetermined value may be, for example, 80% (i.e., 4.8 minutes) or more and less than 100% of the transmission time limit, or 90% (i.e., 5.4 minutes) or more and less than 100%. In step s12, the control unit 10 also determines whether the remaining transmission time of the selected third communication device 3 is sufficient.

[0162] If the result in step s42 is YES, then step s43 is executed. In step s43, the control unit 10 determines whether the recent movement of the selected third communication device 3 is small or not. Specifically, the control unit 10 determines whether the recent movement of the selected third communication device 3 per unit time is less than or equal to a second predetermined value. The unit time may be, for example, one minute or several minutes. The second predetermined value may be, for example, several meters. The control unit 10 can determine the recent movement of the selected third communication device 3 per unit time based on the history of the third position data of the selected third communication device 3 in the storage unit 11. In step s13, the control unit 10 also determines whether the recent movement of the mobile body 300 on which the selected third communication device 3 is mounted is small or not.

[0163] If the result in step s43 is YES, step s44 is executed. In step s44, the control unit 10 determines whether the selected third communication device 3 is currently stopped based on the position data of the selected third communication device 3 in the storage unit 11. In other words, the control unit 10 determines whether the selected third communication device 3 is currently not moving. It can also be said that the control unit 10 determines whether the mobile body 300 on which the selected third communication device 3 is mounted is currently stopped.

[0164] If the result in step s44 is YES, then in step s45, the control unit 10 determines the selected third communication device 3 as the direct communication device 3 that directly receives the target large-capacity data from the target second communication device 2.

[0165] After step s45, in step s46, the control unit 10 determines whether it has determined a first predetermined number P of direct communication devices 3 that will directly receive the target large-capacity data from the target second communication device 2. If it is determined to be YES in step s16, that is, if P direct communication devices 3 for the relay route (large) have been determined, the processing in step s31 ends.

[0166] If the result in step s42 is NO, step s41 is executed again. If the result in step s43 is NO, step s41 is executed again. If the result in step s44 is NO, step s41 is executed again. If the result in step s46 is NO, step s41 is executed again. In the second and subsequent executions of step s41, the control unit 10 newly selects the third communication device 3 that is closest to the target second communication device 2 from among several third communication devices 3 located within the communication area 120 of the target second communication device 2, excluding the third communication device 3 selected up to that point. Thereafter, the control unit 10 operates in the same manner.

[0167] As can be understood from the above explanation, in this example, the control unit 10 determines that the third communication device 3, which is located close to the target second communication device 2, has a large remaining transmission time, has moved little in the most recent time, and is not currently moving, will be the direct communication device 3 that directly receives large amounts of data from the target second communication device 2.

[0168] Thus, by determining the third communication device 3, which has the smallest recent movement, as the direct communication device 3, it becomes less likely that the direct communication device 3 will be located far from the target second communication device 2 when the target second communication device 2 actually transmits large amounts of data. Therefore, the direct communication device 3 can appropriately relay the target large-capacity data.

[0169] Furthermore, by determining that the third communication device 3, which is not currently moving, is the direct communication device 3, it becomes less likely that the direct communication device 3 will be located far from the target second communication device 2 when the target second communication device 2 actually transmits large amounts of data. Therefore, the direct communication device 3 can appropriately relay the target large amounts of data.

[0170] Figure 11 is a flowchart showing an example of step s32. In step s32, as shown in Figure 11, step s51 is performed first. Here, the storage unit 11 stores first position data representing the location of server 1. In step s51, the control unit 10 calculates the straight-line distance between the target second communication device 2 and server 1 based on the first position data in the storage unit 11 and the second position data of the target second communication device 2.

[0171] Next, in step s52, the control unit 10 determines the number of target indirect communication devices 3 to be installed on one relay route (large) based on the straight-line distance obtained in step s51. For example, the control unit 10 obtains a division value by dividing the straight-line distance obtained in step s51 by the communication distance (e.g., 1 km) of the third communication device 3 in Wi-Fi HaLow compliant communication. The communication distance of the third communication device 3 in Wi-Fi HaLow compliant communication is stored in the storage unit 11. Next, the control unit 10 obtains an integer N by rounding up the first decimal place of the obtained division value. Then, the control unit 10 takes the value M (=N-1) obtained by subtracting 1 from the obtained integer N as the number of indirect communication devices 3 to be installed on one relay route (large). For example, if the straight-line distance is 3.8 km, the integer N will be "4", and the control unit 10 will set the number of indirect communication devices 3 to be installed on one relay route (large) to "3". Furthermore, if the straight-line distance is 4.2 km, the integer N becomes "5", and the control unit 10 sets the number of indirect communication devices 3 installed in one relay route (large) to "4". Hereafter, the number of indirect communication devices 3 installed in one relay route (large), which is determined in step s52, may be referred to as the "number of devices M".

[0172] Next, in step s53, the control unit 10 determines the indirect communication device 3 for each of the first predetermined number P relay routes (large) from a plurality of third communication devices 3 within the monitoring area 500.

[0173] In step s53, the control unit 10 determines M intermediate points by dividing the distance between the target second communication device 2 and the server 1 into equal parts, the same number as the integer N obtained in step s52. If the straight-line distance between the target second communication device 2 and the server 1 is 3.8 km, then 3 intermediate points are set between the target second communication device 2 and the server 1.

[0174] Furthermore, in step s53, the control unit 10 selects a third communication device 3 (referred to as the specified third communication device 3) that satisfies specific conditions from among the multiple third communication devices 3 in the monitoring area 500. The specific conditions consist of, for example, a first condition, a second condition, a third condition, and a fourth condition. The specified third communication device 3 is a third communication device 3 that satisfies all of the first, second, third, and fourth conditions.

[0175] The first condition is that it is not a direct communication device 3 of the first predetermined number P. The second condition is the condition corresponding to step s42 above, that the remaining transmission time indicated by the remaining transmission time data is equal to or greater than the first predetermined value above. The third condition is the condition corresponding to step s43 above, that the amount of movement per unit time most recently is less than or equal to the second predetermined value above. The unit time may be, for example, one minute or several minutes. The fourth condition is the condition corresponding to step s44 above, that it is currently stopped.

[0176] For each of the M intermediate points between the target second communication device 2 and the server 1, the control unit 10 identifies the x-th closest specific third communication device 3 from a selection of specific third communication devices 3. x is an integer variable that varies from 1 to P. For each of the M intermediate points, the control unit 10 identifies P specific third communication devices 3 that are close to that intermediate point.

[0177] The control unit 10 changes x by one from 1 to P, and assigns the M specific third communication devices 3 that are the x-th closest to each of the M intermediate points to the M indirect communication devices 3 included in one relay route (large). In this way, the indirect communication devices 3 included in each of the first predetermined number P relay routes (large) (in other words, P relay routes (large)) are determined.

[0178] Hereafter, a relay route (large) that includes M specific third communication devices 3 that are the xth closest to each of the M intermediate points, as M indirect communication devices 3, will be referred to as the xth relay route (large). Also, a specific third communication device 3 that is the xth closest to an intermediate point will be referred to as the xth closest indirect communication device 3 to that intermediate point.

[0179] The control unit 10 designates the direct communication device 3 that is the xth closest to the target second communication device 2 from among the first predetermined number P of direct communication devices 3 as the direct communication device 3 of the xth relay route (large). The xth relay route (large) consists of the direct communication device 3 that is the xth closest to the target second communication device 2 and M indirect communication devices 3 that are the xth closest to each of the M intermediate points between the target second communication device 2 and the server 1. The first predetermined number P of relay routes (large) consist of P target relay routes (large) from the 1st relay route (large) (x=1) to the Pth relay route (large) (x=P).

[0180] As can be understood from the above explanation, in this example, the third communication device 3 whose remaining transmission time is equal to or greater than the first predetermined value is used as both the direct communication device 3 and the indirect communication device 3. In other words, the third communication device 3 whose remaining transmission time is equal to or greater than the first predetermined value is used as the third communication device 3 that relays large amounts of data. The control unit 10 determines the value of the first predetermined number P based on the first predetermined value which is compared with the remaining transmission time, for example.

[0181] Here, the integer obtained by dividing 60 minutes by a first predetermined value and rounding up to the first decimal place is called the reference value. If the first predetermined value, which is compared with the remaining transmission time of the third communication device 3, is, for example, 4.8 minutes (80% of the transmission time limit), the reference value becomes 13. The control unit 10 sets the value of the first predetermined number P to, for example, the value obtained by adding the third predetermined value to the reference value. The third predetermined value may be, for example, 5. If the first predetermined value is 4.8 minutes and the third communication device 3 with a remaining transmission time of 4.8 minutes or more is used as a third communication device 3 that relays large-capacity data, the server 1 sets the first predetermined number P to, for example, 18. In other words, the server 1 determines 18 relay routes (large) that relay large-capacity data in multiple third communication devices 3 within the monitoring area 500, based on a 10% duty cycle limit.

[0182] The control unit 10 of server 1 determines a first predetermined number P of relay routes (large) to relay large amounts of data from the target second communication device 2. For each relay route (large), it identifies the minimum remaining transmission time among the multiple third communication devices 3 that constitute the relay route (also called the minimum remaining transmission time). The minimum remaining transmission time can also be called the minimum remaining time. Then, in step s25 of Figure 8 above, the control unit 10 transmits the minimum remaining transmission time identified for each relay route (large) to the target second communication device 2, along with route notification data representing the first predetermined number P of relay routes (large). The data consisting of the minimum remaining transmission time and route notification data is small-capacity data.

[0183] As can be understood from the above explanation, the minimum remaining transmission time for a large relay route will be greater than or equal to a first predetermined value (e.g., 4.8 minutes). On the other hand, the value obtained by multiplying the first predetermined value and the reference value together will be 60 minutes or more. Therefore, the sum of the minimum remaining transmission time (in other words, the minimum remaining time) for a first predetermined number P of large relay routes that are greater than the reference value will be 60 minutes or more (in other words, the unit time with a 10% duty cycle limit). It can also be said that Server 1 determines the multiple large relay routes such that the sum of their minimum remaining transmission time is 60 minutes or more.

[0184] In step s26 above, when the target second communication device 2 distributes large data to a first predetermined number of relay routes (large) and relays them sequentially, for example, it relays the large data sequentially from the first relay route (large) to the Pth relay route (large). Then, after relaying the large data to the Pth relay route (large), if the target second communication device 2 continues to transmit large data, it again relays the large data sequentially from the first relay route (large) to the Pth relay route (large). The target second communication device 2 operates in the same manner thereafter. Note that the order in which large data is relayed in the first predetermined number of relay routes (large) is not limited to the above.

[0185] When the target second communication device 2 relays large data to the xth relay route (large), it transmits the large data for a time that matches the minimum remaining transmission time of the xth relay route (large). For example, if the minimum remaining transmission time of the xth relay route (large) is 5 minutes, the target second communication device 2 transmits the large data for 5 minutes to the direct communication device 3 of the xth relay route (large), and relays the large data to the server 1 via the xth relay route (large) for 5 minutes.

[0186] In this way, the second communication device 2 transmits large-capacity data for the same amount of time as the minimum remaining transmission time of the multiple third communication devices 3 included in each of the first predetermined number P relay routes (large), thereby improving the possibility that each relay route (large) can continuously transmit large-capacity data while adhering to the 10% duty cycle limit. As a result, the time it takes for the large-capacity data transmitted by the second communication device 2 to the server 1 to be relayed by the third communication device 3 and reach the server 1 can be shortened.

[0187] Unlike the example above, the first predetermined number P may be set to the same value as the reference value. For example, consider the case where the first predetermined value compared with the remaining transmission time of the third communication device 3 is 4.8 minutes (80% of the transmission time limit), and the third communication device 3 with a remaining transmission time of 4.8 minutes or more is determined to be the direct communication device 3 and indirect communication device 3 that relay large amounts of data. In this case, the reference value is 13, and the first predetermined number P may be set to 13. Even when the first predetermined number P is set to the same value as the reference value, the relay routes (large) of the first predetermined number P distribute and relay large amounts of data sequentially, improving the possibility that each relay route (large) can continuously transmit large amounts of data while adhering to the 10% duty cycle limit. Even when the first predetermined number P is set to the same value as the reference value, the server 1 will determine the multiple relay routes (large) such that the sum of the minimum remaining transmission times of the multiple relay routes (large) is 60 minutes or more.

[0188] Furthermore, after determining the first predetermined number P of relay routes (large), there is a possibility that a third communication device 3 included in a certain relay route (large) may move, preventing that relay route (large) from relaying large data. As in the example above, even if some relay routes (large) become unable to relay large data due to the first predetermined number P being set larger than the standard value, the first predetermined number P of relay routes (large) can more reliably relay the large data to the server 1. When the target second communication device 2 transmits target large data, if a certain relay route (large) is unable to relay the target large data, it switches to the next relay route (large) and has the next relay route (large) relay the target large data. For example, the target second communication device 2 may determine that a relay route (large) is unable to relay the target large data if it does not receive a response data from the third communication device 3 of the relay route (large) indicating that it has received the transmitted data.

[0189] In this example, after a first predetermined number of relay routes (large) is determined (step s22), each third communication device 3 included in the first predetermined number of relay routes (large) is excluded from the mesh route for the transmission of small-capacity data. This makes it less likely that the remaining transmission time of each third communication device 3 included in the first predetermined number of relay routes (large) will be reduced by the transmission of small-capacity data. Therefore, the possibility of each relay route (large) continuously transmitting large amounts of data while adhering to the 10% duty cycle limit is improved.

[0190] Furthermore, once Server 1 has finished receiving the large-capacity data transmitted by the target second communication device 2, it will undo the removal of each third communication device 3 included in the first predetermined number of relay routes (large) that relayed the large-capacity data from the mesh route, thereby enabling each third communication device 3 to transmit small-capacity data.

[0191] If the mobile body 300 is livestock such as cattle, the server 1 may determine the direct communication device 3 and the indirect communication device 3 depending on the state of the livestock on which the third communication device 3 is installed. For example, if the livestock as the mobile body 300 on which the third communication device 3 is installed is abnormal, the server 1 may determine the direct communication device 3 and the indirect communication device 3 from the third communication devices 3 other than the said third communication device 3. In this way, by not using the third communication device 3 installed on the livestock that has been determined to be abnormal for relaying large amounts of data, even if, for example, the livestock is moved outside the monitoring area 500 and the third communication device 3 installed on the livestock becomes unable to communicate with the second communication device 2 and the other third communication devices 3, the large amounts of data transmitted by the second communication device 2 can still be properly delivered to the server 1. The server 1 can, for example, determine whether the livestock as the mobile body 300 is abnormal based on the determination result data received from the second communication device 2.

[0192] If a third communication device 3 included in the relay route (large) interrupts the relaying (in other words, transmission) of target large-capacity data due to a 10% duty cycle limit when relaying the target large-capacity data, it may send interruption notification data to the target second communication device 2 indicating the interruption of the relay. The interruption notification data is small-capacity data and is transmitted through the mesh network 100. When the target second communication device 2 receives the interruption notification data from the third communication device 3, it may terminate the relaying of the large-capacity data to the relay route (large) including the third communication device 3 and relay the large-capacity data to the next relay route (large).

[0193] Server 1 may be unable to directly identify fewer than the first predetermined number P of third communication devices 3, for reasons such as the small number of third communication devices 3 connected to the target second communication device 2. Furthermore, Server 1 may be unable to identify fewer than P specific third communication devices 3 near the aforementioned midpoint between the target second communication device 2 and Server 1. In such cases, Server 1 will determine a second predetermined number of relay routes (large), which is fewer than the first predetermined number P. The target second communication device 2 then distributes and relays the large-capacity data to these second predetermined number of relay routes (large) determined by Server 1.

[0194] When Server 1 determines a second predetermined number of relay routes (large) that is less than a first predetermined number P, it may send reduction notification data to the target second communication device 2 to notify it that the amount of data of the target large-capacity data will be reduced. The reduction notification data is small-capacity data and is transmitted over a mesh network. Upon receiving the reduction notification data, the target second communication device 2 reduces the amount of data of the target large-capacity data from its original size and transmits it to Server 1 through the second predetermined number of relay routes (large) that is less than the first predetermined number P. The original amount of data is the amount of data of the large-capacity data that would be transmitted if the first predetermined number P of relay routes (large) were determined. For example, consider the case where the target large-capacity data is video data. In this case, the target second communication device 2 may reduce the amount of data of the video data so that the quality of the video represented by the video data is reduced, and then transmit it to Server 1. Alternatively, the target second communication device 2 may reduce the amount of data of the video data so that the duration of the video represented by the video data is shortened, and then transmit it to Server 1. In this case, the target second communication device 2 may transmit the above-mentioned third target mobile object image data if the number of determined multiple relay routes (large) matches the first predetermined number P, and may transmit the above-mentioned first target mobile object image data or second target mobile object image data if the number of determined multiple relay routes (large) is less than the first predetermined number P.

[0195] Thus, when the number of relay routes (large) that relay the target large-capacity data is less than the first predetermined number P, the target second communication device 2 reduces the amount of data in the target large-capacity data, thereby increasing the likelihood that each relay route (large) can continuously relay the target large-capacity data.

[0196] Furthermore, even if the number of determined relay routes (large) is less than the first predetermined number P, Server 1 does not need to send reduction notification data if it is above the threshold value. Also, Server 1 may send reduction notification data if the number of determined relay routes (large) is less than the threshold value.

[0197] If the mobile body 300 is livestock, and the number of relay routes (large) determined by the server 1 for relaying the target large-capacity data is less than a first predetermined number P, then feed for the livestock as the mobile body 300 may be placed around the target second communication device 2, or at least one of sound and light may be generated to guide the livestock as the mobile body 300 to the vicinity of the target second communication device 2. In this case, for example, if the target second communication device 2 determines, based on the route notification data received by the server 1, that the number of relay routes (large) is less than a first predetermined number P, it may control a device that drops livestock feed around the target second communication device 2, or it may control a device that generates at least one of sound and light to guide the livestock to the vicinity of the target second communication device 2.

[0198] For example, when the target second communication device 2 transmits video data to the server 1 as large-capacity data, it may configure the second part of the video data to be relayed via one relay route (large) and the first part of the video data to be relayed via another relay route (large) to be the same data. This allows the server 1 to play back the video data from the target second communication device 2 without interruption.

[0199] In the example above, the target second communication device 2 sequentially relayed large amounts of data through a first predetermined number of relay routes (large), but it is also possible to simultaneously relay multiple different data through multiple relay routes (large) included in the first predetermined number of relay routes (large).

[0200] Server 1 may determine multiple relay route sets for the target second communication device 2, each consisting of multiple relay routes (large). In this case, Server 1 ensures that direct communication devices 3 do not overlap between the multiple relay route sets, and that indirect communication devices 3 do not overlap between the multiple relay route sets. The target second communication device 2 may relay multiple different large-capacity data to multiple relay route sets. For example, suppose a first relay route set and a second relay route set have been determined for the target second communication device 2. In this case, the target second communication device 2 may, for example, have the first relay route set relay camera image data obtained in real time from camera 230 to Server 1, and the second relay route set relay past camera image data stored in storage unit 21 to Server 1. In this case, the first and second relay route sets may be used to transmit at least a portion of the real-time camera image data and at least a portion of the past camera image data at the same time.

[0201] For example, consider a case where server 1 is receiving large-capacity data from one second communication device 2, and at the same time receives start notification data from another second communication device 2. In this case, the relay route (large) that relays the large-capacity data transmitted by one second communication device 2 is designated as the first relay route (large), and the relay route (large) that relays the large-capacity data transmitted by another second communication device 2 is designated as the second relay route (large). Server 1 may determine multiple second relay routes (large) by excluding third communication devices 3 included in multiple first relay routes (large). For example, if multiple first relay routes (large) include 50 third communication devices 3, server 1 may determine the direct communication devices 3 and indirect communication devices of the multiple second relay routes (large) from third communication devices 3 other than those 50 third communication devices 3. As a result, the transmission of large-capacity data transmitted by the second communication device 2 that started transmitting the large-capacity data first is prioritized, and the time it takes for that large-capacity data to reach server 1 is shortened.

[0202] The functions of the elements disclosed herein may be implemented using circuit configurations or processing circuit configurations, including general-purpose processors, dedicated processors, integrated circuits, ASICs ("Application-Specific Integrated Circuits"), conventional circuit configurations, and / or combinations thereof, which are configured to perform the disclosed elements or programmed to perform the disclosed functions. A processor is considered a processing circuit configuration or circuit configuration if it includes transistors and other circuit configurations within it. In this disclosure, a circuit configuration, unit, or means is hardware that performs the listed functions or hardware programmed to perform such functions. Hardware may be any hardware disclosed herein or other known hardware programmed to perform the listed functions or configured to perform such functions. When hardware is a processor which may be considered a certain type of circuit configuration, a circuit configuration, means, or unit is a combination of hardware and software, software used to configure the hardware, and / or a processor.

[0203] As described above, the communication system has been explained in detail, but the above explanation is illustrative in all respects, and this disclosure is not limited thereto. Furthermore, the various examples described above can be combined and applied insofar as they do not contradict each other. And it is understood that countless variations not illustrated can be envisioned without falling outside the scope of this disclosure.

[0204] This disclosure includes the following embodiments. A communication system according to a first embodiment comprises a first communication device, a second communication device, and a plurality of third communication devices, each having a limit on the transmission time per unit time, wherein at least one of the plurality of third communication devices relays first transmission data transmitted by the second communication device to the first communication device, the first communication device determines a plurality of first relay routes for relaying the first transmission data in the plurality of third communication devices based on the limit, and the second communication device distributes and relays the first transmission data to the plurality of first relay routes.

[0205] The communication system according to the second embodiment is the communication system according to the first embodiment, wherein each of the plurality of third communication devices transmits transmission time-related data relating to transmission time to the first communication device, and the first communication device determines the plurality of first relay routes based on the transmission time-related data.

[0206] The third aspect of the communication system is the second aspect of the communication system, wherein the transmission time-related data indicates the remaining time until the limit of the transmission time in the unit time.

[0207] A communication system according to a fourth embodiment is a communication system according to a third embodiment, wherein in each of the plurality of first relay routes, the minimum remaining time of at least one third communication device constituting the first relay route is set as the minimum remaining time of the first relay route, and the first communication device determines the plurality of first relay routes such that the sum of the minimum remaining times of the plurality of first relay routes is equal to or greater than the unit time.

[0208] The fifth embodiment of the communication system is a communication system according to any one of the second to fourth embodiments, wherein each of the plurality of third communication devices transmits location data to the first communication device, and the first communication device determines the plurality of first relay routes based on the transmission time-related data and the location data.

[0209] The communication system according to the sixth embodiment is a communication system according to any one of the second to fifth embodiments, wherein the plurality of third communication devices are provided on each of the plurality of mobile bodies, and the first communication device acquires mobile body-related data relating to at least one of the plurality of mobile bodies, and determines the plurality of first relay routes based on the transmission time-related data and the mobile body-related data.

[0210] The communication system according to the seventh embodiment is a communication system according to any one of the first to sixth embodiments, wherein when the number of the plurality of first relay rates is less than a predetermined number, the second communication device reduces the amount of data of the transmitted data.

[0211] The eighth aspect of the communication system is a communication system according to any one of the first to seventh aspects, wherein at least one of the plurality of third communication devices relays the second transmission data transmitted by the second communication device to the first communication device, the first communication device determines a plurality of second relay routes for relaying the second transmission data in the plurality of third communication devices based on the restrictions, and the second communication device distributes and relays the second transmission data to the plurality of second relay routes.

[0212] The communication system according to the ninth embodiment is a communication system according to the eighth embodiment, wherein the plurality of first relay routes and the plurality of second relay routes are used, and at least a portion of the first transmission data and at least a portion of the second transmission data are transmitted in the same time period.

[0213] The communication system according to the tenth embodiment is a communication system according to any one of the first to ninth embodiments, comprising a fourth communication device, wherein at least one of the plurality of third communication devices relays third transmission data transmitted by the fourth communication device to the first communication device, the first communication device determines a plurality of third relay routes for relaying the third transmission data in the plurality of third communication devices based on the restrictions, and the fourth communication device distributes and relays the third transmission data to the plurality of third relay routes.

[0214] The communication system according to the 11th embodiment is a communication system according to the 10th embodiment, wherein the first communication device determines the plurality of third relay routes by excluding the third communication device included in the plurality of first relay routes.

[0215] The communication system according to the twelfth embodiment is a communication system according to any one of the first to eleventh embodiments, wherein the first transmitted data includes image data.

[0216] A communication system according to the 13th embodiment, which is a communication system according to any one of the first to 12th embodiments, wherein at least one of the plurality of third communication devices relays fourth transmission data transmitted by the second communication device to the first communication device, the amount of data of the fourth transmission data is smaller than the amount of data of the first transmission data, and the first communication device determines the fourth relay route for relaying the fourth transmission data in the plurality of third communication devices without being subject to the above restrictions.

[0217] The communication system according to the 14th embodiment is a communication system according to the 13th embodiment, wherein the fourth relay route is included in a mesh network composed of the first communication device and the plurality of third communication devices.

[0218] The communication system according to the 15th embodiment is a communication system according to the 13th or 14th embodiment, wherein the first communication device excludes the third communication device included in the first relay route from the fourth relay route.

[0219] The communication system according to the 16th embodiment is a communication system according to any one of the first to 15 embodiments, wherein the communication distance between the plurality of third communication devices is greater than the communication distance of the second communication device.

[0220] The first communication device according to the 17th embodiment is the first communication device provided in a communication system according to any one of the first to 16th embodiments.

[0221] The second communication device according to the 18th embodiment is a second communication device provided in a communication system according to any one of the first to 16th embodiments.

[0222] The third communication device according to the 19th embodiment is a third communication device provided in a communication system according to any one of the first to 16th embodiments, wherein the third communication device receives the first transmission data directly from the second communication device, or receives the first transmission data through another third communication device.

[0223] The third communication device according to the 20th embodiment is a third communication device provided in the communication system according to the 15th embodiment, wherein the third communication device is not included in the first relay route and relays the fourth transmission data in the fourth relay route.

[0224] The program according to the 21st aspect is a program for causing a computer device to function as a first communication device according to the 17th aspect.

[0225] The program according to the 22nd aspect is a program for causing a computer device to function as a second communication device according to the 18th aspect.

[0226] The program according to the 23rd embodiment is a program for causing a computer device to function as a third communication device according to the 19th or 20th embodiment.

[0227] The communication method according to the 24th embodiment is such that at least one of a plurality of third communication devices, each having a limit on the transmission time per unit time, relays first transmission data transmitted by a second communication device to a first communication device, the first communication device determines a plurality of first relay routes for relaying the first transmission data in the plurality of third communication devices based on the limit, and the second communication device distributes and relays the first transmission data through the plurality of first relay routes. [Explanation of Symbols]

[0228] 1. First communication device 2. Second communication device 3. Third communication device 5. Communication Systems 11a, 21a Program 300 Mobile Units

Claims

1. First communication device and The second communication device, Multiple third communication devices, each having a limit on the transmission time per unit time, Equipped with, At least one of the plurality of third communication devices relays the first transmission data transmitted by the second communication device to the first communication device. The first communication device determines a plurality of first relay routes for relaying the first transmission data in the plurality of third communication devices based on the restrictions, The second communication device is a communication system that distributes and relays the first transmission data across the plurality of first relay routes.

2. A communication system according to claim 1, Each of the plurality of third communication devices transmits transmission time-related data relating to the transmission time to the first communication device. The first communication device is a communication system that determines the plurality of first relay routes based on the transmission time-related data.

3. A communication system according to claim 2, The transmission time-related data indicates the remaining time until the transmission time limit in the unit time, in a communication system.

4. A communication system according to claim 3, A communication system in which, in each of the plurality of first relay routes, the minimum remaining time of at least one third communication device constituting the first relay route is set as the minimum remaining time of the first relay route, and the first communication device determines the plurality of first relay routes such that the sum of the minimum remaining times of the plurality of first relay routes is equal to or greater than the unit time.

5. A communication system according to claim 2, Each of the aforementioned plurality of third communication devices transmits location data to the first communication device. The first communication device is a communication system that determines the plurality of first relay routes based on the transmission time-related data and the location data.

6. A communication system according to claim 2, The aforementioned plurality of third communication devices are provided on each of the plurality of mobile bodies. The first communication device is Obtain mobile body-related data relating to at least one of the plurality of mobile bodies, A communication system that determines the plurality of first relay routes based on the transmission time-related data and the mobile body-related data.

7. A communication system according to claim 1, A communication system in which, when the number of the plurality of first relay rates is less than a predetermined number, the second communication device reduces the amount of data of the transmitted data.

8. A communication system according to claim 1, At least one of the plurality of third communication devices relays the second transmission data transmitted by the second communication device to the first communication device. The first communication device determines a plurality of second relay routes for relaying the second transmission data in the plurality of third communication devices based on the restrictions, The second communication device is a communication system that distributes and relays the second transmission data across the plurality of second relay routes.

9. A communication system according to claim 8, A communication system in which the plurality of first relay routes and the plurality of second relay routes are used to transmit at least a portion of the first transmission data and at least a portion of the second transmission data at the same time.

10. A communication system according to claim 1, Equipped with a fourth communication device, At least one of the plurality of third communication devices relays the third transmission data transmitted by the fourth communication device to the first communication device. The first communication device determines, based on the restrictions, a plurality of third relay routes for relaying the third transmission data in the plurality of third communication devices. The fourth communication device is a communication system that distributes and relays the third transmission data across the plurality of third relay routes.

11. A communication system according to claim 10, The first communication device is a communication system that determines the plurality of third relay routes by excluding third communication devices that are included in the plurality of first relay routes.

12. A communication system according to claim 1, The first transmitted data includes image data, and is part of a communication system.

13. A communication system according to claim 1, At least one of the plurality of third communication devices relays the fourth transmission data transmitted by the second communication device to the first communication device. The amount of data in the fourth transmission data is smaller than the amount of data in the first transmission data. A communication system in which the first communication device determines a fourth relay route for relaying the fourth transmission data in the plurality of third communication devices, without being based on the restrictions.

14. A communication system according to claim 13, The fourth relay route is a communication system included in a mesh network composed of the first communication device and the plurality of third communication devices.

15. A communication system according to claim 13, The first communication device is a communication system that excludes a third communication device included in the first relay route from the fourth relay route.

16. A communication system according to claim 1, A communication system in which the communication distance between the plurality of third communication devices is greater than the communication distance of the second communication device.

17. A first communication device comprising a communication system according to any one of claims 1 to 16.

18. A second communication device comprising the communication system according to any one of claims 1 to 16.

19. A third communication device comprising the communication system according to any one of claims 1 to 16, The aforementioned third communication device is The first transmission data is received directly from the second communication device, or A third communication device that receives the aforementioned first transmission data through another third communication device.

20. A third communication device comprising the communication system described in claim 15, The third communication device is not included in the first relay route and relays the fourth transmission data in the fourth relay route.

21. A program for causing a computer device to function as the first communication device described in claim 17.

22. A program for causing a computer device to function as the second communication device described in claim 18.

23. A program for causing a computer device to function as the third communication device described in claim 19.

24. At least one of a plurality of third communication devices, each having a limit on the transmission time per unit time, relays the first transmission data transmitted by the second communication device to the first communication device. The first communication device determines a plurality of first relay routes for relaying the first transmission data in the plurality of third communication devices based on the restrictions, The second communication device is a communication method that distributes and relays the first transmission data across the plurality of first relay routes.

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