COMMUNICATION SYSTEM, COMMUNICATION DEVICE, COMMUNICATION METHOD, AND COMMUNICATION PROGRAM

Abstract

To achieve reduction in power consumption.SOLUTION: A communication system 1 includes a first node 20 and a second node 30. The first node 20 configures a multihop network 2. The second node 30 configures a multihop network 2 and is capable of communicating with a server device 50 via a lower-level network NW1 and a mobile gateway 40. The server device is connected to a higher-level network NW2. A second schedule management unit of the second node 30 manages schedule information including communicable-period information indicating a communicable period which the gateway device 40 is present within a communication range enabling communication with the second node 30 via the lower-level network NW1. A second transmission control unit of the second node 30 transmits first communication data addressed to the server device 50, during the communicable period indicated by the communicable-period information, to the server device 50 through the lower-level network NW1 and the gateway 40.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a communication system, a communication device, a communication method, and a communication program. [Background technology]

[0002] A known configuration involves a gateway that relays between a multi-hop network and a higher-level network, and that moves through real space. In such a configuration, while the gateway is in a position where it can communicate with the multi-hop network, communication data transmitted from the multi-hop network reaches the gateway. On the other hand, while the gateway is in a position where it cannot communicate with the multi-hop network, communication data transmitted from the multi-hop network to the gateway does not reach the gateway, which may result in unnecessary power consumption.

[0003] The specifications for multi-hop networks define a state in which the multi-hop network is connected to a higher-level network (Grounded) and a state in which it is not connected to a higher-level network (Floating). However, conventional technologies do not disclose how to control the multi-hop network in consideration of these states. In other words, it has been difficult to reduce power consumption using conventional technologies. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] RFC 6550, "RPL: IPv6 Routing Protocol for Low-Power and Lossy Networks", [online], Internet Engineering Task Force (IETF), [Retrieved June 3, 2021], Internet<URL:https: / / tools.ietf.org / html / rfc6550> Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the embodiments of the present invention is to provide a communication system, a communication device, a communication method, and a communication program that can reduce power consumption. [Means for solving the problem]

[0006] A communication system according to an embodiment includes a plurality of first communication devices forming a multi-hop network, and a second communication device that forms the multi-hop network together with the first communication devices and is capable of communicating with a server device connected to an upper network via a lower network and a movable gateway. The second communication device includes a second schedule management unit and a second transmission control unit. The second schedule management unit manages schedule information including communication period information indicating a communication period during which the gateway is within a communication range in which it can communicate with the second communication device via the lower network. The second transmission control unit transmits first communication data addressed to the server device to the server device via the lower network and the gateway during the communication period indicated by the communication period information. [Brief explanation of the drawings]

[0007] [Figure 1] Schematic diagram of a communication system. [Figure 2] Schematic diagram of the functional configuration of the second node. [Figure 3] FIG. 3 is a schematic diagram showing the data structure of schedule information. [Figure 4] Schematic diagram of the functional configuration of the first node. [Figure 5] Schematic diagram of the gateway's functional configuration. [Figure 6] FIG. 3 is a schematic diagram of the data structure of schedule information. [Figure 7] FIG. 2 is a schematic diagram illustrating the functional configuration of a server device. [Figure 8] 10 is a flowchart of the flow of information processing executed by the second node. [Figure 9] 10 is a flowchart of the flow of information processing executed by the first node. [Figure 10] 10 is a flowchart of the flow of information processing executed by the gateway. [Figure 11] 10 is a flowchart of the flow of information processing executed by the server device. [Figure 12] FIG. 10 is a schematic diagram of a communication system according to a modified example. [Figure 13] FIG. 10 is a schematic diagram of a functional configuration of a second node according to a modified example. [Figure 14] FIG. 10 is a schematic diagram of a functional configuration of a first node according to a modified example. [Figure 15] Hardware configuration diagram. DETAILED DESCRIPTION OF THE INVENTION

[0008] The communication system, communication device, communication method, and communication program of the present embodiment will be described in detail below with reference to the accompanying drawings.

[0009] In the following description of each embodiment, parts denoted by the same reference numerals have substantially the same functions, and descriptions of overlapping parts will be omitted where appropriate.

[0010] (First embodiment) FIG. 1 is a schematic diagram showing an example of a communication system 1 according to the present embodiment.

[0011] The communication system 1 includes a plurality of nodes 10, a gateway 40, and a server device 50.

[0012] The node 10 is an example of a communication device. A plurality of nodes 10 constitute a multi-hop network 2. FIG. 1 shows 14 nodes 10 as an example of the nodes 10 constituting the multi-hop network 2. The number of the plurality of nodes 10 constituting the multi-hop network 2 is not limited to 14.

[0013] The multiple nodes 10 constituting the multi-hop network 2 may be configured with wired or wireless connections. When the multi-hop network 2 is configured with wired connections, the communication method used may be, for example, Ethernet (registered trademark), serial communication, etc. When the multi-hop network 2 is configured with wireless connections, the communication method used may be, for example, WiFi (Wireless Fidelity), Bluetooth (registered trademark), IEEE 802.15.4, etc.

[0014] The communication system 1 includes a first node 20 and a second node 30 as nodes 10.

[0015] The first node 20 is an example of a first communication device. The first node 20 is a node 10 that constitutes the multi-hop network 2. The first node 20 is a node 10 that has a function of communicating with other first nodes 20 or second nodes 30, but does not have a function of communicating with the lower network NW1. FIG. 1 shows 13 first nodes 20, namely, first nodes 20A to first node 20M, as an example of the first nodes 20 that constitute the multi-hop network 2. The number of the multiple first nodes 20 that constitute the multi-hop network 2 is not limited to 13.

[0016] The second node 30 is an example of a second communication device. The second node 30 is a node 10 that constitutes the multi-hop network 2, similar to the first node 20. The second node 30 has a function of communicating with the first node 20. The second node 30 can further communicate with a gateway 40 via a lower network NW1. In particular, the second node 30 can communicate with a server device 50 connected to a higher network NW2 via the lower network NW1 and the movable gateway 40.

[0017] The second node 30 can also function as, for example, a concentrator of the multi-hop network 2. In this embodiment, an example will be described in which the multi-hop network 2 includes one second node 30. That is, in this embodiment, an example will be described in which the entrance / exit from the multi-hop network 2 to the lower network NW1 is configured by one second node 30.

[0018] The second node 30 can be connected to the lower network NW1 via a wired connection or a wireless connection. When the second node 30 connects to the lower network NW1 via a wired connection, the communication method used may be, for example, Ethernet or serial communication. When the second node 30 connects to the lower network NW1 via a wireless connection, the communication method used may be, for example, WiFi, Bluetooth, IEEE 802.15.4, a communication method using millimeter waves, a method for satellite communication, or visible light communication.

[0019] The gateway 40 is connected to the lower network NW1 and the upper network NW2, and relays communications between the server device 50 and each of the second node 30 and the first node 20. The communication methods of the multi-hop network 2, the lower network NW1, and the upper network NW2 are not limited.

[0020] In this embodiment, the gateway 40 is configured to be movable in the real space, and therefore can be intermittently connected to the lower network NW1.

[0021] For example, the gateway 40 is mounted on a moving object that moves in real space. Examples of the moving object include a vehicle, a train, an elevator car that moves up and down in an elevator shaft, and a flying object such as an airplane or a drone.

[0022] Assume that the gateway 40 is mounted on a vehicle. In this case, when the vehicle equipped with the gateway 40 reaches the vicinity of the second node 30, the gateway 40 connects to the lower network NW1. Assume that the gateway 40 is mounted on a train. In this case, when the train equipped with the gateway 40 stops at the station where the second node 30 is installed, the gateway 40 connects to the lower network NW1. Assume that the gateway 40 is mounted on an elevator car. In this case, when the car equipped with the gateway 40 stops at the floor where the second node 30 is located, the gateway 40 connects to the lower network NW1. Assume that the gateway 40 is mounted on an airplane. In this case, when the airplane equipped with the gateway 40 reaches the vicinity of the second node 30, the gateway 40 connects to the lower network NW1.

[0023] As described above, in this embodiment, the gateway 40 is configured to be movable in real space. Therefore, the gateway 40 connects to the lower network NW1 when it satisfies physical conditions, such as being within a communication range where it can communicate with the second node 30. That is, in this embodiment, while the gateway 40 is connected to the lower network NW1, the first node 20 and the second node 30 that make up the multi-hop network 2 can communicate with the server device 50 via the gateway 40.

[0024] Next, an example of the functional configuration of the second node 30 of this embodiment will be described.

[0025] FIG. 2 is a schematic diagram of an example of the functional configuration of the second node 30.

[0026] The second node 30 includes a storage unit 32, a control unit 38, a communication unit 34, and a NW (network) communication unit 36. The storage unit 32, the communication unit 34, the NW communication unit 36, and the control unit 38 are connected to each other so as to be able to exchange data or signals.

[0027] The storage unit 32 stores various types of data. In this embodiment, the storage unit 32 stores schedule information 60. Details of the schedule information 60 will be described later.

[0028] The communication unit 34 communicates with each of the first nodes 20 included in the multi-hop network 2. In the configuration of the multi-hop network 2 shown in FIG. 1 , the communication unit 34 of the second node 30 communicates directly with each of the first nodes 20C, 20G, 20L, and 20M, i.e., with a hop count of 1. The communication unit 34 also communicates with each of the other nodes 10 via one or more other nodes 10.

[0029] Continuing the explanation, returning to Fig. 2, the NW communication unit 36 ​​is connected to the lower network NW1 and communicates with the gateway 40.

[0030] The control unit 38 includes a second schedule management unit 38A, a multi-hop network management unit 38B, and a second transmission control unit 38C. The second transmission control unit 38C includes an application processing unit 38D and a transfer control unit 38E.

[0031] The second schedule management unit 38A, the multi-hop network management unit 38B, the second transmission control unit 38C, the application processing unit 38D, and the transfer control unit 38E are realized, for example, by one or more processors. For example, each unit included in the control unit 38 may be realized by having a processor such as a CPU (Central Processing Unit) execute a program, i.e., by software. Each of the above units may be realized by a processor such as a dedicated IC, i.e., by hardware. Each of the above units may be realized by a combination of software and hardware. When multiple processors are used, each processor may realize one of the units, or may realize two or more of the units.

[0032] The second schedule management unit 38A manages the schedule information 60.

[0033] Schedule information 60 is an example of schedule information.

[0034] The schedule information is information that represents a connection schedule for the gateway 40 included in the communication system 1 to the lower network NW1. The schedule information is information that is shared within the communication system 1. That is, the server device 50, the gateway 40, and the node 10 included in the communication system 1 share the schedule information.

[0035] The schedule information includes one or more pieces of communication period information. The communication period information is information that indicates a communication period. The communication period is a period during which the gateway 40 is present within a communication range in which it can communicate with the second node 30 via the lower network NW1. In other words, the communication period is a period during which the gateway 40 is connected to the lower network NW1. In other words, the communication period is a period during which the gateway 40 is connected to the lower network NW1, thereby enabling communication between the second node 30 and the gateway 40.

[0036] The communication available period information may be information that represents a certain time, or information that represents a period from a predetermined date and time to another date and time. In this embodiment, an example will be described in which the communication available period information is information that represents a period from a connection date and time when the gateway 40 starts connecting to the lower network NW1 to a disconnection date and time when the gateway 40 is disconnected from the lower network NW1.

[0037] FIG. 3 is a schematic diagram showing an example of the data configuration of schedule information 60. Schedule information 60 includes communication possible period information. For example, communication possible period information is represented by a pair of connection date and time and disconnection date and time. That is, for example, communication possible period information is information that represents a communication possible period from the connection date and time to the disconnection date and time. FIG. 3 shows an example in which schedule information 60 includes multiple pieces of communication possible period information.

[0038] Note that the communication available period information may be information that represents a communication available period and is not limited to information expressed as a pair of connection date and time and disconnection date and time. For example, the communication available period information may be information that registers pairs of connection time and disconnection time for each predetermined schedule category, such as weekdays, weekends, and holidays, like a train or bus timetable. Furthermore, the communication available period information may be information that specifies a period expressed by time, without including information regarding the year, month, and date.

[0039] Returning to Figure 2, the explanation will continue. The second schedule management unit 38A stores and manages schedule information 60 in the storage unit 32. In this embodiment, the second schedule management unit 38A will be described as an example in which schedule information distributed in advance from the server device 50 via the lower network NW1 and the gateway 40 is stored in advance in the storage unit 32 as schedule information 60.

[0040] The multi-hop network management unit 38B configures a multi-hop network 2 with each of the multiple first nodes 20 via the communication unit 34. The multi-hop network 2 can be configured using various methods such as RPL (IPv6 Routing Protocol for Low power and Lossy Network), Bluetooth Mesh, and ZigBee (registered trademark).

[0041] The multihop network management unit 38B includes the schedule information 60 as schedule information in a control message used to manage and maintain the multihop network 2, and transmits the control message to the first node 20. When RPL is used to configure the multihop network 2, the schedule information is included in a control message called a DODAG Information Object (DIO) and transmitted to the first node 20. Through this transmission process, the multihop network management unit 38B distributes the schedule information distributed from the server device 50 to each of the multiple first nodes 20 included in the multihop network 2. Therefore, the schedule information is shared among the multiple nodes 10, gateway 40, and server device 50 in the multihop network 2.

[0042] Note that a method that does not use a control message may be used as a means for transmitting the schedule information 60 to the first node 20. For example, a control header of an application message may be used as a means for transmitting the schedule information 60, or a message dedicated to transmitting the schedule information 60 may be used.

[0043] The second schedule management unit 38A may include, as schedule information, all of the plurality of pieces of communication possible period information included in the schedule information 60 stored in the storage unit 32 in the control message. The second schedule management unit 38A may also include, as schedule information, some of the plurality of pieces of communication possible period information included in the schedule information 60 stored in the storage unit 32 in the control message. When some of the schedule information included in the schedule information 60 is to be included in the control message, a predetermined number of pieces of communication possible period information may be extracted from the plurality of pieces of communication possible period information included in the schedule information 60 in order from closest to the current time toward a future time, and the extracted pieces of communication possible period information may be included in the control message as schedule information.

[0044] Next, the second transmission control unit 38C will be described. The second transmission control unit 38C controls the transmission of the first communication data and the second communication data. Note that the terms "transmission" and "transmission control" include both transmission originating from the control unit itself and transfer of data received from other devices.

[0045] The first communication data is an example of communication data that is transmitted from the first node 20 or the second node 30 as a transmission origin and is communicated with the server device 50 as a final destination. For this reason, the first communication data includes identification information of the server device 50 as information representing the final destination.

[0046] The second communication data is an example of communication data that is communicated with server device 50 or gateway 40 as the transmission origin and with first node 20 or second node 30 as the final destination. For this reason, the second communication data includes identification information of first node 20 or second node 30 as information representing the final destination. The second communication data with first node 20 as the final destination includes identification information of second node 30 as the relay destination, and includes identification information of first node 20 as the final destination.

[0047] In this embodiment, the second transmission control unit 38C performs transmission control to transmit the first communication data to the server device 50 via the lower network NW1 and the gateway 40 during the communication possible period represented by the communication possible period information in the schedule information 60.

[0048] In this embodiment, the second transmission control unit 38C includes an application processing unit 38D and a transfer control unit 38E.

[0049] The application processing unit 38D processes application data addressed to its own node received from the first node 20. The own node means its own node 10. The application processing unit 38D may generate the application data received from the first node 20 as new first communication data whose final destination is the server device 50. Furthermore, the application processing unit 38D may generate the first communication data autonomously, regardless of the reception of application data.

[0050] Furthermore, when the application processing unit 38D receives second communication data having its own node as the final destination from the server device 50 via the gateway 40 and the lower network NW1, the application processing unit 38D processes the second communication data.

[0051] The transfer control unit 38E controls the transfer of communication data between the first node 20 and the server device 50. When the communication unit 34 receives first communication data, which is communication data whose final destination is the server device 50, the transfer control unit 38E transfers the first communication data to the server device 50 via the NW communication unit 36. When the NW communication unit 36 ​​receives second communication data whose final destination is a node other than the node itself, the transfer control unit 38E transfers the second communication data to the first node 20 via the communication unit 34.

[0052] When controlling the transmission of first communication data, which is communication data whose final destination is the server device 50, the second transmission control unit 38C, which includes the application processing unit 38D and the transfer control unit 38E, adjusts the transmission timing of the first communication data based on the schedule information 60. In detail, the second transmission control unit 38C reads the schedule information 60 from the storage unit 32. Then, the second transmission control unit 38C performs transmission control to transmit the first communication data to the server device 50 via the lower network NW1 and the gateway 40 during a communication possible period indicated by communication possible period information included in the schedule information 60.

[0053] That is, the second transmission control unit 38C waits for transmission of the first communication data to the gateway 40 while the gateway 40 is not connected to the lower network NW1. On the other hand, the second transmission control unit 38C controls transmission so that the first communication data is transmitted to the gateway 40 during a communication enabled period, which is a period when the gateway 40 is connected to the lower network NW1.

[0054] When the current time falls within the communication period represented by the communication period information, the second transmission control unit 38C may transmit the first communication data to the gateway 40. Furthermore, the second transmission control unit 38C may wait a predetermined time after the current time falls within the communication period represented by the communication period information, and then transmit the first communication data to the gateway 40 within the communication period.

[0055] Furthermore, when the gateway 40 is in a connected state in which it is connected to the lower network NW1, the second transmission control unit 38C may periodically measure a communication delay that occurs between the node itself and the gateway 40. Then, the second transmission control unit 38C may transmit the first communication data to the gateway 40 when the current time is a time that is earlier than a time within the communication period indicated by the communication period information by an amount of time that corresponds to the communication delay.

[0056] In addition, the second transmission control unit 38C may transmit the first communication data to the gateway 40 when the current time is within the communication period represented by the communication period information and the connection between the gateway 40 and the lower network NW1 can be confirmed.

[0057] The method for confirming the connection between the gateway 40 and the lower network NW1 is not limited. For example, the second transmission control unit 38C confirms the connection between the gateway 40 and the lower network NW1 by sending a connection confirmation message to the gateway 40 and determining the response to the control message. Specifically, for example, the second transmission control unit 38C sends an ICMP Echo Request message to the gateway 40 as a connection confirmation message. Then, the second transmission control unit 38C confirms the connection by determining whether or not an ICMP Echo Reply has been received as a response from the gateway 40.

[0058] The second transmission control unit 38C may also confirm the connection between the gateway 40 and the lower network NW1 by determining a notification received from the lower network NW1 that indicates the connection status of the gateway 40. The second transmission control unit 38C may also confirm the connection between the gateway 40 and the lower network NW1 by checking the link status, which is the connection status of the communication interface of the NW communication unit 36.

[0059] Next, an example of the functional configuration of the first node 20 of this embodiment will be described.

[0060] FIG. 4 is a schematic diagram of an example of the functional configuration of the first node 20. As shown in FIG.

[0061] The first node 20 includes a storage unit 22, a control unit 28, and a communication unit 24. The storage unit 22, the communication unit 24, and the control unit 28 are connected so as to be able to exchange data or signals.

[0062] The storage unit 22 stores various types of data. In this embodiment, the storage unit 22 stores schedule information 62.

[0063] The communication unit 24 communicates with each of the nodes 10 included in the multi-hop network 2. That is, the communication unit 24 communicates with each of the other first nodes 20 and second nodes 30 other than the node itself, directly or via another first node 20.

[0064] Control unit 28 includes first schedule management unit 28A, multi-hop network management unit 28B, and first transmission control unit 28C. First transmission control unit 28C includes application processing unit 28D and transfer control unit 28E. First schedule management unit 28A, multi-hop network management unit 28B, first transmission control unit 28C, application processing unit 28D, and transfer control unit 28E are realized by, for example, one or more processors.

[0065] The first schedule management unit 28A manages schedule information 62. The first schedule management unit 28A stores and manages the schedule information 62 in the storage unit 22. For example, the first schedule management unit 28A stores and manages schedule information distributed from the second node 30 as schedule information 62 in the storage unit 22. In detail, the first schedule management unit 28A stores, as schedule information 62, schedule information included in a control message received from the second node 30 directly or via another first node 20 in the storage unit 22. The data structure of the schedule information 62 is the same as the data structure of the schedule information 60 (see FIG. 3).

[0066] As described above, the second schedule management unit 38A of the second node 30 may include, in the control message, some of the communication possible period information pieces included in the schedule information 60 stored in the storage unit 32 of the second node 30 as schedule information. In this case, the first schedule management unit 28A of the first node 20 stores and manages, in the storage unit 22, some of the communication possible period information pieces included in the schedule information 60 managed by the second node 30 as schedule information 62.

[0067] Through these processes, the first schedule management unit 28A shares schedule information with multiple nodes 10 in the multi-hop network 2. That is, the server device 50, the gateway 40, and the nodes 10 included in the communication system 1 share schedule information including the same communication available period information.

[0068] The multi-hop network management unit 28B configures the multi-hop network 2 with each of the plurality of first nodes 20 and second nodes 30 via the communication unit 24.

[0069] The first transmission control unit 28C controls the transmission of the first communication data and the second communication data.

[0070] In this embodiment, the first transmission control unit 28C performs transmission control to transmit first communication data to the server device 50 via the second node 30, the lower network NW1, and the gateway 40 during the communication period represented by the communication period information in the schedule information 62.

[0071] In this embodiment, the first transmission control unit 28C includes an application processing unit 28D and a transfer control unit 28E.

[0072] The application processing unit 28D processes application data addressed to its own node that is received from another node 10. The application processing unit 28D may generate the application data received from another node 10 as new first communication data whose final destination is the server device 50. Furthermore, the application processing unit 28D may generate the first communication data autonomously, regardless of the reception of application data.

[0073] Furthermore, when the application processing unit 28D receives second communication data from the server device 50 via the gateway 40, the lower network NW1, and the second node 30, the application processing unit 28D processes the second communication data, the second communication data being the final destination of the application processing unit 28D.

[0074] The transfer control unit 28E controls the transfer of communication data to and from other nodes 10. When the communication unit 24 receives first communication data from another node 10, the transfer control unit 38E transfers the first communication data to the second node 30. When the communication unit 24 receives second communication data that includes a node other than the node itself as a final destination, the transfer control unit 28E transfers the second communication data to the other first node 20 via the communication unit 24.

[0075] When transmitting first communication data, which is communication data whose final destination is the server device 50, the first transmission control unit 28C, which includes the application processing unit 28D and the transfer control unit 28E, adjusts the transmission timing of the first communication data based on the schedule information 62. In particular, the application processing unit 28D reads the schedule information 62 from the storage unit 22. Then, the first transmission control unit 28C performs transmission control to transmit the first communication data to the server device 50 via the second node 30, the lower network NW1, and the gateway 40 during the communication possible period indicated by the communication possible period information included in the schedule information 62.

[0076] That is, the first transmission control unit 28C waits for transmission of the first communication data to the gateway 40 via the second node 30 during a period when the gateway 40 is not connected to the lower network NW1. On the other hand, the first transmission control unit 28C transmits the first communication data to the gateway 40 via the second node 30 during a communication enabled period when the gateway 40 is connected to the lower network NW1. The first transmission control unit 28C may control transmission of the first communication data with the server device 50 as the final destination and the second node 30 as the relay destination.

[0077] When the current time falls within the communication period represented by the communication period information, the first transmission control unit 28C may transmit the first communication data to the second node 30. Furthermore, the second transmission control unit 38C may wait a predetermined time after the current time falls within the communication period represented by the communication period information, and then transmit the first communication data to the second node 30 within the communication period.

[0078] Furthermore, when the gateway 40 is in a connected state in which it is connected to the lower network NW1, the first transmission control unit 28C may periodically measure a communication delay that occurs between the node itself and the gateway 40. Then, the first transmission control unit 28C may transmit the first communication data to the second node 30 when the current time is a time that is earlier than a time within the communication period indicated by the communication period information by an amount of time that corresponds to the communication delay.

[0079] In addition, the first transmission control unit 28C may transmit the first communication data to the second node 30 when the current time is within the communication period represented by the communication period information and the connection between the gateway 40 and the lower network NW1 is confirmed by the second node 30.

[0080] Next, an example of the functional configuration of the gateway 40 of this embodiment will be described. As described above, the gateway 40 is configured to be movable in the real space. The gateway 40 moves in the real space in accordance with the schedule information shared within the communication system 1. For example, a control unit of a mobile object equipped with the gateway 40 controls a drive unit of the mobile object so that the mobile object moves in the real space in accordance with the schedule information.

[0081] FIG. 5 is a schematic diagram of an example of the functional configuration of the gateway 40. As shown in FIG.

[0082] The gateway 40 includes a storage unit 42, a control unit 48, a NW communication unit 44, and a NW communication unit 46. The storage unit 42, the NW communication unit 44, the NW communication unit 46, and the control unit 48 are connected to each other so as to be able to exchange data or signals.

[0083] The storage unit 42 stores various types of data. In this embodiment, the storage unit 42 stores schedule information 64 and first management information 70. Details of the schedule information 64 and the first management information 70 will be described later.

[0084] The NW communication unit 44 is connectable to the lower network NW1 and communicates with the second node 30 connected to the lower network NW1. When the NW communication unit 44 receives a connection confirmation message from the second node 30, it transmits, for example, an ICMP Echo Reply as a response signal to the second node 30. The NW communication unit 46 is connected to the upper network NW2 and communicates with the server device 50 connected to the upper network NW2.

[0085] The control unit 48 includes a fourth schedule management unit 48A and a fourth transfer control unit 48C. The fourth schedule management unit 48A and the fourth transfer control unit 48C are realized by, for example, one or more processors.

[0086] The fourth schedule management unit 48A stores and manages schedule information 64 in the storage unit 42. In the present embodiment, an example will be described in which the fourth schedule management unit 48A stores schedule information distributed from the server device 50 in advance in the storage unit 32 as schedule information 64.

[0087] The schedule information 64 is information that associates downstream NW identification information of the downstream network NW1 to which the gateway 40 can connect with communication-enabled period information that indicates a communication-enabled period during which the gateway 40 is within a communication range in which it can communicate with the second node 30 via the downstream network NW1 identified by the downstream NW identification information. The communication-enabled period information is the same as described above. That is, the fourth schedule management unit 48A manages, as the schedule information 64, information in which downstream NW identification information is further associated with each of one or more pieces of communication-enabled period information included in the schedule information 60 and the schedule information 62 described above.

[0088] 6 is a schematic diagram showing an example of the data configuration of the schedule information 64. The schedule information 64 is information that associates communication available period information with subordinate NW identification information. The communication available period information is the same as above. The subordinate NW identification information is identification information for identifying the subordinate network NW1.

[0089] Returning to Figure 5, the explanation will continue. The fourth schedule management unit 48A stores and manages schedule information distributed from the server device 50 as schedule information 64 in the storage unit 32. Furthermore, when the gateway 40 connects to the lower network NW1, the fourth schedule management unit 48A transmits the schedule information received from the server device 50 to the second node 30 connected to the lower network NW1. In detail, when the gateway 40 connects to the lower network NW1, the fourth schedule management unit 48A transmits a group of communication available period information associated with the lower NW identification information of the lower network NW1 in the schedule information 64 as schedule information to the second node 30 connected to the lower network NW1.

[0090] The fourth transfer control unit 48C controls the transfer of communication data between the second node 30 and the server device 50. That is, the fourth transfer control unit 48C controls the transfer of the first communication data and the second communication data.

[0091] When the NW communication unit 44 receives the first communication data from the second node 30, the fourth transfer control unit 48C transfers the first communication data to the server device 50 via the NW communication unit 46.

[0092] When the NW communication unit 46 receives the second communication data from the server device 50, the fourth transfer control unit 48C transfers the second communication data to the second node 30 via the lower level network NW1.

[0093] When controlling the transfer of second communication data, which is communication data having the first node 20 or the second node 30 as its final destination, the fourth transfer control unit 48C adjusts the transfer timing of the second communication data based on the schedule information 64. In detail, the fourth transfer control unit 48C reads the schedule information 64 from the storage unit 42. In addition, the fourth transfer control unit 48C identifies the lower NW identification information of the lower network NW1 to which the second node 30, which is set as the final destination or relay destination included in the second communication data received from the server device 50, is connected.

[0094] The memory unit 42 of the gateway 40 pre-stores first management information 70 that associates lower NW identification information, identification information of a second node 30 connected to the lower network NW1 identified by the lower NW identification information, and identification information of a first node 20 included in the multi-hop network 2 that includes the second node 30.

[0095] The fourth transfer control unit 48C identifies, from the first management information 70, downstream NW identification information that corresponds to the identification information of the second node 30 that is set as the final destination or relay destination included in the second communication data received from the server device 50. Then, the fourth transfer control unit 48C reads communication available period information in the schedule information 64 that corresponds to the identified downstream NW identification information.

[0096] The fourth transfer control unit 48C performs transfer control to transfer the second communication data to the second node 30 via the lower-level network NW1 during the communication enabled period indicated by the read communication enabled period information.

[0097] That is, while the fourth transfer control unit 48C is not connected to the lower network NW1, the fourth transfer control unit 48C waits to transfer the second communication data to the second node 30 connected to the lower network NW1. Furthermore, during a communication enabled period, which is a period while the fourth transfer control unit 48C is connected to the lower network NW1, the fourth transfer control unit 48C performs transfer control to transfer the second communication data to the second node 30 connected to the lower network NW1.

[0098] When the current time falls within the communication period represented by the communication period information, the fourth transfer control unit 48C may transfer the second communication data to the second node 30. Furthermore, the fourth transfer control unit 48C may wait a predetermined time after the current time falls within the communication period represented by the communication period information, and then transfer the second communication data to the second node 30 within the communication period.

[0099] Furthermore, when the fourth transfer control unit 48C is in a connected state in which it is connected to the lower network NW1, it may periodically measure a communication delay that occurs between it and the second node 30. Then, the fourth transfer control unit 48C may transfer the second communication data to the second node 30 when the current time is a time that is within the communication period indicated by the communication period information and that is earlier by an amount of time that corresponds to the communication delay.

[0100] Furthermore, when the current time falls within the communication period indicated by the communication period information and the connection with the lower network NW1 is confirmed, the fourth transfer control unit 48C may transmit the second communication data to the second node 30. The method for confirming the connection with the lower network NW1 may be the same as that of the second transmission control unit 38C.

[0101] Next, an example of the functional configuration of the server device 50 of this embodiment will be described.

[0102] FIG. 7 is a schematic diagram illustrating an example of the functional configuration of the server device 50. As shown in FIG.

[0103] The server device 50 includes a storage unit 52, a network communication unit 56, and a control unit 58. The storage unit 52, the network communication unit 56, and the control unit 58 are connected to each other so as to be able to exchange data or signals.

[0104] The storage unit 52 stores various types of data. In this embodiment, the storage unit 52 stores schedule information 66 and first management information 70. Details of the schedule information 66 will be described later. As the first management information 70 has been described above, a description thereof will be omitted here.

[0105] The NW communication unit 56 is connected to the upper network NW2. That is, the NW communication unit 56 communicates with the gateway 40 via the upper network NW2.

[0106] The control unit 58 includes a third schedule management unit 58A and a third transmission control unit 58C. The third schedule management unit 58A and the third transmission control unit 58C are realized by, for example, one or more processors.

[0107] The third schedule management unit 58A manages schedule information 66. The data configuration of the schedule information 66 is similar to that of the schedule information 64 (see FIG. 6).

[0108] For example, the third schedule management unit 58A stores and manages schedule information 66 in the storage unit 52.

[0109] In this embodiment, the third schedule management unit 58A of the server device 50 generates schedule information and distributes it to each of the gateway 40, the second node 30, and the first node 20 included in the communication system 1.

[0110] For example, the third schedule management unit 58A acquires information indicating which lower network NW1 the gateway 40 will connect to and during which communication period, via a Web API (Application Programming Interface), a user interface, etc. Then, based on the acquired information, the third schedule management unit 58A generates schedule information that associates communication period information indicating the communication period with lower NW identification information of the lower network NW1 to which the gateway 40 will connect during the communication period indicated by the communication period information.

[0111] The third schedule management unit 58A stores the generated schedule information as schedule information 66 in the storage unit 52. Furthermore, the third schedule management unit 58A distributes the generated schedule information 62 to the gateway 40, the second node 30 connected to the lower network NW1, and the first node 20 that constitutes the multi-hop network 2 together with the second node 30, while the gateway 40 is connected to the lower network NW1.

[0112] As a result of the distribution process by the third schedule management unit 58A of the server device 50, the server device 50, the gateway 40, the second node 30, and the node 10 included in the communication system 1 share schedule information including the same communication available period information.

[0113] The timing of schedule information distribution by control unit 58 and the unit of communication available period information included in the distributed schedule information are not limited. For example, third schedule management unit 58A periodically distributes schedule information. Furthermore, when new schedule information is generated or when schedule information is changed, third schedule management unit 58A may distribute the newly generated schedule information or the changed schedule information.

[0114] The third transmission control unit 58C controls the transmission and reception of communication data. The third transmission control unit 58C processes the first communication data received from the gateway 40.

[0115] When controlling the transmission of second communication data, which is communication data whose final destination is the first node 20 or the second node 30, the third transmission control unit 58C adjusts the transmission timing of the second communication data based on the schedule information 66. In detail, the third transmission control unit 58C reads the schedule information 66 from the storage unit 52. In addition, the third transmission control unit 58C identifies the lower NW identification information of the lower network NW1 to which the second node 30, which is the final destination or relay destination of the second communication data, is connected.

[0116] The memory unit 52 of the server device 50 pre-stores first management information 70 that associates lower NW identification information, identification information of a second node 30 connected to a lower network NW1 identified by the lower NW identification information, and identification information of a first node 20 included in a multi-hop network 2 that includes the second node 30.

[0117] The third transmission control unit 58C identifies, from the first management information 70, the downstream NW identification information corresponding to the identification information of the second node 30 that is the final destination or relay destination of the second communication data. Then, the third transmission control unit 58C reads, from the schedule information 66, communication available period information that corresponds to the identified downstream NW identification information.

[0118] The third transmission control unit 58C performs transmission control to transmit the second communication data to the second node 30 via the gateway 40 and the lower network NW1 during the communication possible period indicated by the read communication possible period information.

[0119] That is, the third transmission control unit 58C waits for transmission of the second communication data to the second node 30 connected to the lower network NW1 during a period when the gateway 40 is not connected to the lower network NW1. Furthermore, the third transmission control unit 58C performs transmission control to transmit the second communication data to the second node 30 connected to the lower network NW1 during a communication possible period when the gateway 40 is connected to the lower network NW1.

[0120] When the current time falls within the communication period represented by the communication period information, the third transmission control unit 58C may transmit the second communication data to the second node 30. Furthermore, the third transmission control unit 58C may wait a predetermined time after the current time falls within the communication period represented by the communication period information, and then transmit the second communication data to the second node 30 within the communication period.

[0121] Furthermore, when the gateway 40 is in a connected state in which it is connected to the lower network NW1, the third transmission control unit 58C may periodically measure a communication delay that occurs between itself and the second node 30. Then, the third transmission control unit 58C may transmit the second communication data to the second node 30 when the current time is a time that is within the communication period indicated by the communication period information and that is an amount of time that corresponds to the communication delay.

[0122] Furthermore, when the current time falls within the communication period indicated by the communication period information and the connection between the gateway 40 and the lower network NW1 is confirmed, the third transmission control unit 58C may transmit the second communication data to the second node 30. The method for confirming the connection with the lower network NW1 may be the same as that of the second transmission control unit 38C.

[0123] Next, an example of the flow of information processing executed in the communication system 1 of this embodiment will be described.

[0124] FIG. 8 is a flowchart showing an example of the flow of information processing executed by the second node 30.

[0125] The second transmission control unit 38C of the second node 30 determines whether to transmit or transfer the first communication data whose final destination is the server device 50 (step S100). The second transmission control unit 38C makes the determination in step S100 by determining whether the application processing unit 38D has generated the first communication data whose final destination is the server device 50. The second transmission control unit 38C also determines whether to transfer the first communication data by determining whether the communication data received from the first node 20 is the first communication data whose final destination is the server device 50.

[0126] If the determination in step S100 is negative (step S100: No), this routine ends. If the determination in step S100 is positive (step S100: Yes), the process proceeds to step S102.

[0127] In step S102, the second transmission control unit 38C reads the schedule information 60 from the storage unit 32 (step S102). Then, the second transmission control unit 38C performs transmission control to transmit the first communication data determined in step S100 to the server device 50 via the lower network NW1 and the gateway 40 during the communication possible period indicated by the communication possible period information included in the schedule information 60 (step S104). Then, this routine ends.

[0128] FIG. 9 is a flowchart showing an example of the flow of information processing executed by the first node 20.

[0129] The first transmission control unit 28C of the first node 20 determines whether to transmit or transfer first communication data, which is communication data whose final destination is the server device 50 (step S200). The first transmission control unit 28C makes the determination in step S200 by determining whether the application processing unit 28D has generated first communication data whose final destination is the server device 50. The first transmission control unit 28C also determines whether to transfer the first communication data by determining whether communication data received from another first node 20 is first communication data whose final destination is the server device 50.

[0130] If the determination in step S200 is negative (step S200: No), this routine ends. If the determination in step S200 is positive (step S200: Yes), the process proceeds to step S202.

[0131] In step S202, the first transmission control unit 28C reads the schedule information 62 from the storage unit 22 (step S202). Then, the first transmission control unit 28C performs transmission control to transmit the first communication data determined in step S200 to the server device 50 via the second node 30, the lower network NW1, and the gateway 40 during the communication possible period indicated by the communication possible period information included in the schedule information 62 (step S204). Then, this routine ends.

[0132] FIG. 10 is a flowchart showing an example of the flow of information processing executed by the gateway 40.

[0133] The fourth forwarding control unit 48C of the gateway 40 determines whether to forward the second communication data, which is communication data whose final destination is the first node 20 or the second node 30 (step S300). The fourth forwarding control unit 48C makes the determination in step S300 by determining whether the second communication data has been received from the server device 50.

[0134] If the determination in step S300 is negative (step S300: No), this routine ends. If the determination in step S300 is positive (step S300: Yes), the process proceeds to step S302.

[0135] In step S302, fourth transfer control unit 48C reads schedule information 64 from storage unit 42 (step S302).

[0136] Then, the fourth forwarding control unit 48C identifies from the first management information 70 the lower NW identification information of the lower NW1 connected to the second node 30 that is set as the final destination or relay destination included in the second communication data determined in step S300 (step S304).

[0137] The fourth transfer control unit 48C reads the communication available period information corresponding to the downstream NW identification information identified in step S304 from the schedule information 64 read in step S302 (step S306).

[0138] Then, the fourth transfer control unit 48C performs transfer control to transfer the second communication data to the second node 30 used for identification in step S304 via the lower network NW1 during the communication available period indicated by the communication available period information read in step S306 (step S308). Then, this routine ends.

[0139] FIG. 11 is a flowchart showing an example of the flow of information processing executed by the server device 50.

[0140] The third transmission control unit 58C of the server device 50 determines whether to transmit second communication data, which is communication data whose final destination is the first node 20 or the second node 30 (step S400). The fourth transfer control unit 48C makes the determination in step S400 by determining whether the second communication data has been generated or whether there is second communication data to be transmitted.

[0141] If the determination in step S400 is negative (step S400: No), this routine ends. If the determination in step S400 is positive (step S400: Yes), the process proceeds to step S402.

[0142] In step S402, the third transmission control unit 58C reads the schedule information 66 from the storage unit 52 (step S402).

[0143] Then, the third transmission control unit 58C identifies the lower NW identification information of the lower NW1 connected to the second node 30 that is set as the final destination or relay destination included in the second communication data determined in step S400 from the first management information 70 (step S404).

[0144] The third transmission control unit 58C reads the communication available period information corresponding to the downstream NW identification information identified in step S404 from the schedule information 66 read in step S402 (step S406).

[0145] Then, the third transmission control unit 58C performs transfer control to transfer the second communication data to the second node 30 used for identification in step S404 via the gateway 40 and the lower network NW1 during the communication available period indicated by the communication available period information read in step S406 (step S408). Then, this routine ends.

[0146] As described above, the communication system 1 of this embodiment includes the first node 20 (first communication device) and the second node 30 (second communication device). The first node 20 constitutes a multi-hop network 2. The second node 30 constitutes the multi-hop network 2 together with the first node 20, and is capable of communicating with a server device 50 connected to a higher-level network NW2 via a lower-level network NW1 and a movable gateway 40.

[0147] The second node 30 includes a second schedule management unit 38A and a second transmission control unit 38C. The second schedule management unit 38A manages schedule information 60. The schedule information 60 includes communication period information that indicates a communication period during which the gateway 40 is within a communication range in which it can communicate with the second node 30 via the lower network NW1. The second transmission control unit 38C transmits first communication data addressed to the server device 50 to the server device 50 via the lower network NW1 and the gateway 40 during the communication period indicated by the communication period information.

[0148] Thus, in this embodiment, the second transmission control unit 38C of the second node 30 transmits the first communication data to the server device 50 via the lower network NW1 and the gateway 40 during a communication period in which the movable gateway 40 is within a communication range in which it can communicate with the second node 30 via the lower network NW1.

[0149] That is, in the communication system 1 of this embodiment, the first communication data is not transmitted from the second node 30 to the gateway 40 while the gateway 40 is not connected to the lower network NW1. In addition, in the communication system 1 of this embodiment, the first communication data is transmitted from the second node 30 to the gateway 40 while the gateway 40 is connected to the lower network NW1.

[0150] Therefore, in the communication system 1 of this embodiment, during the period when the gateway 40 is not connected to the lower network NW1, the transmission of the first communication data from the second node 30 to the lower network NW1 can be suppressed, thereby suppressing unnecessary power consumption.

[0151] Therefore, the communication system 1 of this embodiment can reduce power consumption.

[0152] In addition, in the communication system 1 of this embodiment, it is possible to prevent the gateway 40 from transmitting the first communication data to the lower network NW1 during the period when the gateway 40 is not connected to the lower network NW1, so that in addition to the above effects, it is possible to prevent the retransmission of unnecessary communication data, the power consumption associated with the retransmission of unnecessary communication data, and data loss.

[0153] Furthermore, in the communication system 1 of this embodiment, it is possible to suppress unnecessary retransmission of communication data, and therefore, in addition to the above effects, it is possible to improve data reliability and shorten transfer time.

[0154] In addition, in the communication system 1 of this embodiment, the first transmission control unit 28C of the first node 20 transmits the first communication data to the server device 50 via the second node 30, the lower network NW1, and the gateway 40 during the communication period represented by the communication period information of the schedule information 62.

[0155] Therefore, in the communication system 1 of this embodiment, during the period when the gateway 40 is not connected to the lower network NW1, each of the multiple first nodes 20 included in the multi-hop network 2 can be prevented from transmitting first communication data to the lower network NW1 via the second node 30.

[0156] Therefore, the communication system 1 of this embodiment can further reduce unnecessary power consumption. Also, the communication system 1 of this embodiment can reduce congestion in the multi-hop network 2 due to unnecessary communication. Also, the communication system 1 of this embodiment can reduce transfer time.

[0157] In addition, in the communication system 1 of this embodiment, the fourth forwarding control unit 48C of the gateway 40 forwards the second communication data to the second node 30 via the lower network NW1 during the communication period represented by the communication period information in the schedule information 64 corresponding to the lower NW identification information of the lower network NW1 connected to the destination second node 30.

[0158] Thus, in this embodiment, the fourth forwarding control unit 48C of the gateway 40 performs forwarding control to forward the second communication data to the second node 30 via the lower network NW1 during a communication period when the gateway 40 is within a communication range where it can communicate with the second node 30 via the lower network NW1.

[0159] That is, in the communication system 1 of this embodiment, while the gateway 40 is not connected to the lower network NW1, the second communication data is not transferred from the gateway 40 to the second node 30. In addition, in the communication system 1 of this embodiment, while the gateway 40 is connected to the lower network NW1, the second communication data is transferred from the gateway 40 to the second node 30.

[0160] Therefore, in the communication system 1 of this embodiment, when the gateway 40 is not connected to the lower network NW1, the transmission of second communication data from the gateway 40 to the lower network NW1 can be suppressed, thereby suppressing unnecessary power consumption.

[0161] Therefore, the communication system 1 of this embodiment can further reduce power consumption.

[0162] In addition, in the communication system 1 of this embodiment, the third transmission control unit 58C of the server device 50 transmits the second communication data to the second node 30 via the gateway 40 and the lower network NW1 during the communication period represented by the communication period information in the schedule information 66 corresponding to the lower NW identification information of the lower network NW1 connected to the destination second node 30.

[0163] Thus, in this embodiment, the third transmission control unit 58C of the server device 50 transmits the second communication data to the second node 30 via the gateway 40 and the lower network NW1 during a communication period in which the gateway 40 is within a communication range in which it can communicate with the second node 30 via the lower network NW1.

[0164] That is, in the communication system 1 of this embodiment, while the gateway 40 is not connected to the lower network NW1, the server device 50 does not transmit the second communication data to the gateway 40. In addition, in the communication system 1 of this embodiment, while the gateway 40 is connected to the lower network NW1, the server device 50 transmits the second communication data to the gateway 40.

[0165] Therefore, in the communication system 1 of this embodiment, while the gateway 40 is not connected to the lower network NW1, transmission of the second communication data from the server device 50 to the lower network NW1 via the gateway 40 can be suppressed, thereby suppressing unnecessary power consumption. Therefore, the communication system 1 of this embodiment can further reduce power consumption.

[0166] (Variation 1) In the above embodiment, a configuration has been described as an example in which both the first node 20 and the second node 30 included in the communication system 1 adjust the transmission timing of the first communication data based on the schedule information (schedule information 60, schedule information 62). That is, in the above embodiment, a configuration has been described as an example in which both the first node 20 and the second node 30 perform transmission control to transmit the first communication data to the server device 50 via the lower network NW1 and the gateway 40 during a communication available period indicated by communication available period information included in the schedule information. However, in the communication system 1, it is sufficient that at least one of the first node 20 and the second node 30 executes the above transmission process of adjusting the transmission timing of the first communication data based on the schedule information (schedule information 60, schedule information 62).

[0167] Furthermore, in the above embodiment, an example has been described in which both the gateway 40 and the server device 50 included in the communication system 1 adjust the timing of transmission of the second communication data based on the schedule information (schedule information 64, schedule information 66). That is, in the above embodiment, an example has been described in which both the gateway 40 and the server device 50 transmit the second communication data to the node 10 via the gateway 40 and the lower network NW1 during the communication available period indicated by the communication available period information included in the schedule information. However, in the communication system 1, it is sufficient that at least one of the gateway 40 and the server device 50 transmits the second communication data based on the schedule information (schedule information 64, schedule information 66).

[0168] (Variation 2) In the above embodiment, an example was described in which the third schedule management unit 58A of the server device 50 generates schedule information and distributes it to each of the gateway 40, the second node 30, and the first node 20 included in the communication system 1.

[0169] However, the present invention is not limited to a configuration in which the server device 50 generates and distributes schedule information. For example, the fourth schedule management unit 48A of the gateway 40 may generate schedule information and distribute it to each of the server device 50, the second node 30, and the first node 20.

[0170] This will be explained using Fig. 5. In this case, the fourth schedule management unit 48A of the gateway 40 acquires information indicating which lower network NW1 the gateway 40 will connect to and during which communication available period, for example, via a Web API or a user interface. Then, based on the acquired information, the fourth schedule management unit 48A generates schedule information that associates communication available period information indicating the communication available period with lower NW identification information of the lower network NW1 to which the gateway 40 will connect during the communication available period indicated by the communication available period information.

[0171] The fourth schedule management unit 48A stores the generated schedule information in the storage unit 42 as schedule information 64. Furthermore, the fourth schedule management unit 48A distributes the generated schedule information to each of the second nodes 30 connected to the lower network NW1 and the first nodes 20 that, together with the second node 30, constitute the multi-hop network 2 while the fourth schedule management unit 48A is connected to the lower network NW1. Furthermore, the fourth schedule management unit 48A distributes the generated schedule information to the server device 50.

[0172] The second node 30 and the first node 20 to which the schedule information has been distributed may store and manage the distributed schedule information as schedule information 60 and schedule information 62, respectively, in the same manner as in the above embodiment.

[0173] Furthermore, the third schedule management unit 58A of the server device 50 to which the schedule information has been distributed may store and manage the distributed schedule information as schedule information 66 in the storage unit 52.

[0174] (Variation 3) In the above embodiment, an example has been described in which the multi-hop network 2 includes one second node 30. That is, in the above embodiment, an example has been described in which the gateway from the multi-hop network 2 to the lower network NW1 is configured by one second node 30.

[0175] However, the number of second nodes 30 included in the multi-hop network 2 may be plural. In other words, there may be plural entrances and exits from the multi-hop network 2 to the lower network NW1.

[0176] FIG. 12 is a schematic diagram showing an example of a communication system 1B of this modified example.

[0177] The communication system 1B includes a plurality of nodes 10, a gateway 40, and a server device 50. The gateway 40 and the server device 50 are the same as those in the above embodiment.

[0178] In this modification, a plurality of nodes 10 constitute a multi-hop network 2B. In this modification, a communication system 1B includes a first node 21 and a second node 31 as the plurality of nodes 10 that constitute the multi-hop network 2B. The first node 21 is an example of a first communication device. The second node 31 is an example of a second communication device.

[0179] That is, in this modification, the communication system 1B includes a first node 21 instead of the first node 20 and a second node 31 instead of the second node 30 in the communication system 1 of the above embodiment.

[0180] In this modification, the multi-hop network 2B includes a plurality of second nodes 31 instead of one second node 30. That is, in this modification, an example will be described in which an entrance / exit from the multi-hop network 2B to the lower network NW1 is configured by a plurality of second nodes 31.

[0181] 12 shows an example in which a multi-hop network 2B includes three second nodes 30, namely, second node 30A to second node 30C. The number of second nodes 30 included in the multi-hop network 2B may be any number and is not limited to three.

[0182] In this embodiment, a configuration in which multiple second nodes 31A are connected to different lower level networks NW1 will be described as an example. For example, a configuration in which the second node 31A is connected to the lower level network NW1A, the second node 31B is connected to the lower level network NW1B, and the second node 31C is connected to the lower level network NW1C will be described as an example. The lower level networks NW1A to NW1C are one example of the lower level network NW1.

[0183] In this modification, the gateway 40 moves in the real space, which causes the lower network NW1 to which the gateway 40 is connected to change. Furthermore, as the gateway 40 moves in the real space, the second node 31 connected to the gateway 40 via the lower network NW1, among the multiple second nodes 31 included in the multi-hop network 2B, also changes.

[0184] The gateway 40 and the server device 50 included in the communication system 1B of this modification each execute the same processes as those in the above embodiment.

[0185] The second node 31 and the first node 21 respectively execute the same processing as the second node 30 and the first node 20 in the above embodiment. The second node 31 may transfer the first communication data to another second node 30 connected to the lower network NW1 to which the gateway 40 is connected. The first node 21 may also transmit the first communication data to the second node 30 connected to the lower network NW1 to which the gateway 40 is connected.

[0186] FIG. 13 is a schematic diagram of an example of the functional configuration of the second node 31 of this modified example.

[0187] The second node 31 includes a storage unit 33, a control unit 39, a communication unit 34, and a NW communication unit 36. The storage unit 33, the communication unit 34, the NW communication unit 36, and the control unit 39 are connected to each other so as to be able to exchange data or signals. The communication unit 34 and the NW communication unit 36 ​​are the same as those in the above embodiment.

[0188] The storage unit 33 stores various types of data. In this modification, the storage unit 33 stores schedule information 61 and second management information 72.

[0189] Schedule information 61 is an example of schedule information. The data structure of schedule information 61 is similar to that of schedule information 64 and schedule information 66 in the above embodiment (see FIG. 6).

[0190] That is, the schedule information 61 is information that associates downstream NW identification information of the downstream network NW1 to which the gateway 40 can connect with communication available period information that indicates a communication available period during which the gateway 40 is within a communication range in which it can communicate with the second node 31 via the downstream network NW1 identified by the downstream NW identification information. The communication available period information is the same as above. That is, the second schedule management unit 39A manages, as the schedule information 61, information in which downstream NW identification information is further associated with each of one or more pieces of communication available period information included in the schedule information 60 managed by the second schedule management unit 38A of the above embodiment.

[0191] The second management information 72 is information for managing the lower network NW1 to which the second node 31 is connected. The second management information 72 is information that associates the identification information of the second node 31 with the lower NW identification information of the lower network NW1 to which the second node 31, which is identified by the identification information of the second node 31, is connected.

[0192] The control unit 39 includes a second schedule management unit 39A, a multi-hop network management unit 38B, and a second transmission control unit 39C. The second transmission control unit 39C includes an application processing unit 39D and a transfer control unit 39E.

[0193] The second schedule management unit 39A, the multi-hop network management unit 39B, the second transmission control unit 39C, the application processing unit 39D, and the transfer control unit 39E are realized by, for example, one or more processors.

[0194] The second schedule management unit 39A is similar to the second schedule management unit 38A of the above embodiment, except that it manages schedule information 61 instead of schedule information 60.

[0195] The second transmission control unit 39C controls the transmission of the first communication data and the second communication data, similar to the second transmission control unit 38C in the above embodiment.

[0196] The second transmission control unit 39C includes an application processing unit 39D and a transfer control unit 39E. Similar to the application processing unit 38D in the above embodiment, the application processing unit 39D processes application data addressed to the node itself received from the first node 21. The application processing unit 39D may also generate first communication data independently of the reception of application data.

[0197] Furthermore, when the application processing unit 39D receives second communication data having its own node as the final destination from the server device 50 via the gateway 40 and the lower network NW1, the application processing unit 39D processes the second communication data.

[0198] Similar to the transfer control unit 38E in the above embodiment, the transfer control unit 39E controls the transfer of communication data between the first node 21 and the server device 50. In this modification, the transfer control unit 39E further controls the transfer of communication data between the first node 21 and another second node 31.

[0199] When transmitting the first communication data, the second transmission control unit 39C, which includes the application processing unit 39D and the transfer control unit 39E, adjusts the transmission timing of the first communication data based on the schedule information 61, similar to the second transmission control unit 38C. That is, the second transmission control unit 39C adjusts the transmission timing of the first communication data based on the schedule information 61 instead of the schedule information 60.

[0200] Specifically, the second transmission control unit 39C reads the schedule information 61 from the storage unit 32. Then, the second transmission control unit 39C performs transmission control to transmit the first communication data to the server device 50 via the lower network NW1 and the gateway 40 during the communication possible period indicated by the communication possible period information included in the schedule information 61.

[0201] That is, in this modification, the second transmission control unit 39C of the second node 31, like the second transmission control unit 38C in the above embodiment, waits to transmit the first communication data to the gateway 40 while the gateway 40 is not connected to the lower network NW1. Also, like the second transmission control unit 38C in the above embodiment, the second transmission control unit 39C controls transmission so that the first communication data is transmitted to the gateway 40 during a communication enabled period, which is a period when the gateway 40 is connected to the lower network NW1.

[0202] In this modification, the second transmission control unit 39C of the second node 31 may further control the transmission of the second communication data to another second node 31 connected to the lower network NW1 to which the gateway 40 is connected at the scheduled transmission time. The scheduled transmission time may be the current time or any time in the future.

[0203] In detail, the second transmission control unit 39C of the second node 31 performs transmission control to transmit the first communication data to the server device 50 via the second node 31 connected to the lower network NW1, the lower network NW1, and the gateway 40 during the communication period represented by the communication period information corresponding to the lower NW identification information of the lower network NW1 to which the gateway 40 is connected at the scheduled transmission time in the schedule information 61.

[0204] More specifically, the second transmission control unit 39C identifies downstream NW identification information associated with communication available period information including the scheduled transmission time of the first communication data in the schedule information 61. Then, the second transmission control unit 39C reads the identification information of the second node 30 corresponding to the identified downstream NW identification information in the second management information 72. The second transmission control unit 39C performs transmission control to transmit the first communication data to the second node 31 identified by the read identification information of the second node 31 during the communication available period represented by the communication available period information corresponding to the identified downstream NW identification information in the schedule information 61.

[0205] That is, in this modified example, the second transmission control unit 39C of the second node 31 may perform transmission control to transmit the first communication data to another second node 30 connected to the lower network NW1 to which the gateway 40 is scheduled to connect at the scheduled transmission time.

[0206] This will be explained using Figure 12. For example, assume that the gateway 40 moves in the real space according to the schedule information and becomes connected to the lower network NW1A. Also assume that the second node 31B transmits the first communication data. In this case, the second transmission control unit 39C of the second node 31B transmits the first communication data to the second node 31A connected to the lower network NW1A during a connectable period in which the gateway 40 is connected to the lower network NW1A.

[0207] FIG. 14 is a schematic diagram of an example of the functional configuration of the first node 21 of this modified example.

[0208] The first node 21 includes a storage unit 23, a control unit 29, and a communication unit 24. The storage unit 23, the communication unit 24, and the control unit 29 are connected to each other so as to be able to exchange data or signals. The communication unit 24 is the same as in the above embodiment.

[0209] The storage unit 23 stores various types of data. In this modification, the storage unit 23 stores schedule information 63 and second management information 72. The second management information 72 is the same as above.

[0210] Schedule information 63 is an example of schedule information. The data structure of schedule information 63 is similar to that of schedule information 64 and schedule information 66 in the above embodiment (see FIG. 6).

[0211] That is, the schedule information 63 is information that associates downstream NW identification information of the downstream network NW1 to which the gateway 40 can connect with communication available period information that indicates a communication available period during which the gateway 40 is within a communication range in which it can communicate with the second node 31 via the downstream network NW1 identified by the downstream NW identification information. The communication available period information is the same as above. That is, the first schedule management unit 29A manages, as the schedule information 63, information in which downstream NW identification information is further associated with each of one or more pieces of communication available period information included in the schedule information 62 managed by the first schedule management unit 28A of the above embodiment.

[0212] The control unit 29 includes a first schedule management unit 29A, a multi-hop network management unit 38B, and a second transmission control unit 39C. The second transmission control unit 39C includes an application processing unit 39D and a transfer control unit 39E.

[0213] The system includes a first schedule management unit 29A, a multi-hop network management unit 28B, and a first transmission control unit 29C. The first transmission control unit 29C includes an application processing unit 29D and a transfer control unit 29E. The first schedule management unit 29A, the multi-hop network management unit 28B, the first transmission control unit 29C, the application processing unit 29D, and the transfer control unit 29E are realized by, for example, one or more processors.

[0214] The first schedule management unit 29A is similar to the first schedule management unit 29A of the above embodiment, except that it manages schedule information 63 instead of schedule information 62.

[0215] The first transmission control unit 29C controls the transmission of the first communication data and the second communication data, similar to the first transmission control unit 28C in the above embodiment.

[0216] The first transmission control unit 29C includes an application processing unit 29D and a transfer control unit 29E. Similar to the application processing unit 28D in the above embodiment, the application processing unit 29D processes application data addressed to its own node received from another first node 21 or second node 31. The application processing unit 29D may also generate first communication data independently of the reception of application data.

[0217] Furthermore, when the application processing unit 29D receives second communication data having its own node as the final destination from the server device 50 via the gateway 40 and the lower network NW1, the application processing unit 29D processes the second communication data.

[0218] Similar to the transfer control unit 28E in the above embodiment, the transfer control unit 29E controls the transfer of communication data between another first node 21 and the server device 50. In this modification, the transfer control unit 29E further controls the transfer of communication data between second nodes 31.

[0219] When transmitting the first communication data, the first transmission control unit 29C, which includes the application processing unit 29D and the transfer control unit 29E, adjusts the transmission timing of the first communication data based on the schedule information 63, similar to the first transmission control unit 28C. That is, the first transmission control unit 29C adjusts the transmission timing of the first communication data based on the schedule information 63 instead of the schedule information 62.

[0220] In detail, the first transmission control unit 29C reads the schedule information 63 from the storage unit 32. Then, the first transmission control unit 29C performs transmission control to transmit the first communication data to the server device 50 via the lower network NW1 and the gateway 40 during the communication possible period indicated by the communication possible period information included in the schedule information 63.

[0221] That is, in this modification, the first transmission control unit 29C of the first node 21, like the first transmission control unit 28C in the above embodiment, waits to transmit the first communication data to the gateway 40 during a period when the gateway 40 is not connected to the lower network NW1. Also, like the first transmission control unit 28C in the above embodiment, the first transmission control unit 29C controls transmission so that the first communication data is transmitted to the gateway 40 during a communication enabled period when the gateway 40 is connected to the lower network NW1.

[0222] In addition, in this modified example, the first transmission control unit 29C of the first node 21 may further control the transmission of the first communication data to the second node 31 connected to the lower network NW1 to which the gateway 40 is connected at the scheduled transmission time.

[0223] In detail, the first transmission control unit 29C of the first node 21 performs transmission control to transmit the first communication data to the server device 50 via the second node 31 connected to the lower network NW1, the lower network NW1, and the gateway 40 during the communication period represented by the communication period information corresponding to the lower NW identification information of the lower network NW1 to which the gateway 40 is connected at the scheduled transmission time in the schedule information 63.

[0224] More specifically, the first transmission control unit 29C identifies downstream NW identification information associated with communication available period information including the scheduled transmission time of the first communication data in the schedule information 63. Then, the first transmission control unit 29C reads identification information of the second node 31 corresponding to the identified downstream NW identification information in the second management information 72. The first transmission control unit 29C performs transmission control to transmit the first communication data to the second node 31 identified by the read identification information of the second node 31 during the communication available period represented by the communication available period information corresponding to the identified downstream NW identification information in the schedule information 63.

[0225] That is, in this modified example, the first transmission control unit 29C of the first node 21 may perform transmission control to transmit the first communication data to the second node 31 connected to the lower network NW1 to which the gateway 40 is scheduled to connect at the scheduled transmission time.

[0226] This will be explained using Figure 12. For example, assume that the gateway 40 moves in the real space according to the schedule information and becomes connected to the lower network NW1A. Also assume that the first node 21E transmits first communication data whose final destination is the server device 50. In this case, the first transmission control unit 29C of the first node 21E transmits the first communication data to the second node 31A connected to the lower network NW1A during a connectable period in which the gateway 40 is connected to the lower network NW1A.

[0227] As described above, in this modification, the multi-hop network 2B includes a plurality of second nodes 31. The second transmission control unit 39C of the second node 31 performs transmission control to transmit the first communication data to the server device 50 via the second node 31 connected to the lower network NW1, the lower network NW1, and the gateway 40, during a communication available period indicated by communication available period information corresponding to the lower NW identification information of the lower network NW1 to which the gateway 40 is connected at the scheduled transmission time in the schedule information 61.

[0228] Therefore, in the communication system 1B of this modified example, during the period when the gateway 40 is not connected to the lower network NW1, the transmission of the first communication data from the second node 31 to the lower network NW1 can be suppressed, thereby suppressing unnecessary power consumption.

[0229] Therefore, the communication system 1B of this embodiment can reduce power consumption.

[0230] Next, an example of the hardware configuration of the node 10, the gateway 40, and the server device 50 in the above embodiment and modified example will be described.

[0231] FIG. 15 is a hardware configuration diagram of an example of the node 10, gateway 40, and server device 50 according to the above embodiment and modifications.

[0232] The node 10, gateway 40, and server device 50 in the above embodiment and variant examples are equipped with a control device such as a CPU (Central Processing Unit) 90B, a storage device such as a ROM (Read Only Memory) 90C and a RAM (Random Access Memory) 90D, an I / F section 90A that interfaces with various devices, and a bus 90E that connects each section, and are configured as hardware using a normal computer.

[0233] In the node 10, gateway 40, and server device 50 of the above embodiment and modification, the CPU 90B reads a program from the ROM 90C onto the RAM 90D and executes it, thereby realizing each of the above units on the computer.

[0234] The programs for executing the above-described processes executed by the node 10, the gateway 40, and the server device 50 in the above-described embodiment and modifications may be provided in the form of being pre-installed in the ROM 90C.

[0235] Furthermore, the programs for executing the above processes executed by the node 10, gateway 40, and server device 50 in the above embodiment and modified examples may be stored in an installable or executable file format on a computer-readable storage medium such as a CD-ROM, CD-R, memory card, DVD (Digital Versatile Disc), or flexible disk (FD) and provided as a computer program product. Furthermore, the programs for executing the above processes executed by the node 10, gateway 40, and server device 50 in the above embodiment and modified examples may be stored on a computer connected to a network such as the Internet and provided by downloading via the network. Furthermore, the programs for executing the above processes executed by the node 10, gateway 40, and server device 50 in the above embodiment and modified examples may be provided or distributed via a network such as the Internet.

[0236] Although the embodiments and modifications of the present invention have been described above, they are presented as examples and are not intended to limit the scope of the invention. These novel embodiments and modifications can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as defined in the claims. [Explanation of symbols]

[0237] 1, 1B communication system 2. 2B multi-hop network 10 nodes 20, 21 1st Node 30, 31 Second Node 40 Gateway 50 Server device

Claims

1. a plurality of first communication devices that form a multi-hop network; a second communication device that configures the multi-hop network together with the first communication device and is capable of communicating with a server device connected to a higher-level network via a lower-level network and a movable gateway; the second communication device, a second schedule management unit that manages schedule information including communication available period information that indicates a communication available period during which the gateway is within a communication range in which it can communicate with the second communication device via the lower network; a second transmission control unit that transmits first communication data addressed to the server device to the server device via the lower level network and the gateway during the communication available period indicated by the communication available period information; A communication system comprising:

2. The first communication device a first schedule management unit that manages the schedule information; a first transmission control unit that transmits the first communication data to the server device via the second communication device, the lower level network, and the gateway during the communication available period indicated by the communication available period information; The communication system of claim 1 .

3. The server device a third schedule management unit that manages the schedule information that associates lower NW identification information of the lower network to which the gateway can be connected with the communication available period information that indicates the communication available period during which the gateway exists within a communication range in which it can communicate with the second communication device via the lower network identified by the lower NW identification information; a third transmission control unit that transmits second communication data addressed to the first communication device or the second communication device to the second communication device via the gateway and the lower network during the communication available period indicated by the communication available period information corresponding to the lower NW identification information of the lower network connected to the second communication device that is the destination in the schedule information; The communication system of claim 1 , comprising:

4. The gateway a fourth schedule management unit that manages the schedule information that associates lower NW identification information of the lower network to which the gateway can be connected with the communication available period information that indicates the communication available period during which the gateway exists within a communication range in which it can communicate with the second communication device via the lower network identified by the lower NW identification information; a fourth transfer control unit that transfers second communication data addressed to the first communication device or the second communication device to the second communication device via the lower network during the communication available period represented by the communication available period information corresponding to the lower NW identification information of the lower network connected to the second communication device that is addressed in the schedule information; The communication system of claim 1 , comprising:

5. The schedule information is Generated and distributed in advance by the gateway or the server device, The communication system of claim 1 .

6. the multi-hop network includes a plurality of the second communication devices; The communication system of claim 1 .

7. The second schedule management unit managing the schedule information in which lower NW identification information of the lower network to which the gateway can be connected and the communication available period information representing the communication available period when the gateway is present within a communication range in which it can communicate with the second communication device via the lower network identified by the lower NW identification information are associated; The second transmission control unit transmit the first communication data to the server device via the second communication device connected to the lower network, the lower network, and the gateway during the communication available period indicated by the communication available period information corresponding to the lower NW identification information of the lower network to which the gateway is connected at the scheduled transmission time in the schedule information; 7. The communication system according to claim 6.

8. A communication device that configures a multi-hop network together with a plurality of first communication devices that configure the multi-hop network, and that can communicate with a server device connected to a higher-level network via a lower-level network and a movable gateway, a second schedule management unit that manages schedule information including communication available period information that indicates a communication available period during which the gateway is within a communication range in which the gateway can communicate with the communication device via the lower network; a second transmission control unit that transmits first communication data addressed to the server device to the server device via the lower level network and the gateway during the communication available period indicated by the communication available period information; A communication device comprising:

9. 1. A communication method executed by a communication device that configures a multi-hop network together with a plurality of first communication devices that configure the multi-hop network, and that is capable of communicating with a server device connected to a higher-level network via a lower-level network and a movable gateway, the method comprising: managing schedule information including communication period information indicating a communication period during which the gateway is within a communication range in which it can communicate with the communication device via the lower level network; transmitting first communication data addressed to the server device via the lower level network and the gateway during the communication available period indicated by the communication available period information; A communication method including:

10. A communication program executed by a computer that configures a multi-hop network together with a plurality of first communication devices that configure the multi-hop network, and that is capable of communicating with a server device connected to a higher-level network via a lower-level network and a movable gateway, the program comprising: managing schedule information including communication period information indicating a communication period during which the gateway is within a communication range in which it can communicate with a communication device via the lower level network; transmitting first communication data addressed to the server device via the lower level network and the gateway during the communication available period indicated by the communication available period information; Communications programs, including:

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