WO2019008707A1 - Control device for wireless network, control method for wireless network, and communication system - Google Patents

Control device for wireless network, control method for wireless network, and communication system Download PDF

Info

Publication number
WO2019008707A1
WO2019008707A1 PCT/JP2017/024681 JP2017024681W WO2019008707A1 WO 2019008707 A1 WO2019008707 A1 WO 2019008707A1 JP 2017024681 W JP2017024681 W JP 2017024681W WO 2019008707 A1 WO2019008707 A1 WO 2019008707A1
Authority
WO
WIPO (PCT)
Prior art keywords
node
state
wireless
relay
battery
Prior art date
Application number
PCT/JP2017/024681
Other languages
French (fr)
Japanese (ja)
Inventor
鈴木　貴久
浩一郎 山下
康志 栗原
Original Assignee
富士通株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 富士通株式会社 filed Critical 富士通株式会社
Priority to PCT/JP2017/024681 priority Critical patent/WO2019008707A1/en
Priority to JP2019528266A priority patent/JP6852792B2/en
Publication of WO2019008707A1 publication Critical patent/WO2019008707A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/02—Power saving arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/18—Self-organising networks, e.g. ad-hoc networks or sensor networks
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

  • the present invention relates to a control device for a radio network, a control method for a radio network, and a communication system.
  • a wireless sensor network (WSN) system has been proposed in which a sensor is connected to a wireless communication node operating by environmental power generation such as sunlight and the sensing information is collected by multi-hop communication.
  • the sensing data is aggregated in a gateway (GW) by multi-hop communication, and is accumulated in the server from the GW via the Internet.
  • GW gateway
  • a wireless communication node performing multi-hop communication operates in a relay state in which communication is relayed and in a non-relay state in which communication is not relayed.
  • a wireless communication node in a non-relay state (referred to as a non-relay node) does not perform a relay operation. Whether the wireless communication node operates as a relay node or as a non-relay node is determined by the operation setting of the wireless communication node.
  • the power consumption of the relay node is greater than the power consumption of the non-relay node. For this reason, even when operating under the same conditions, the remaining battery power of the relay node may be exhausted before the remaining battery power of the non-relay node is exhausted. Therefore, there are the following technologies.
  • the server side collects communication quality information (LQI: Link Quality Indicator) between the remaining battery level of each node and the peripheral nodes.
  • the remaining battery capacity of the relay node is predicted, and the relay node is changed to a non-relay node according to an instruction from the server before the remaining battery power is exhausted, and the remaining battery power is recovered by environmental power generation.
  • a non-relay node around the relay node to be changed to a non-relay node is selected on the server side based on LQI, and the network is maintained by instructing the relay node to change (see, for example, Patent Document 1).
  • the wireless communication node may be disconnected from the wireless network and not connected due to deterioration of the wireless communication environment or the like.
  • the wireless communication node in the unconnected state transmits a connection request.
  • the wireless communication node receiving the connection request is in the relay state, the connection with the connection request source is made in response to the connection request, and if it is in the non-relay state, the operation is not performed It is possible to do.
  • the wireless communication node in the unconnected state can not connect to the wireless network.
  • An object of the present invention is to provide a control apparatus for a wireless network, a control method for a wireless network, and a communication system capable of properly performing reconnection of a disconnection node.
  • each wireless node includes an energy harvesting unit and a storage battery, receives and drives power of at least one of the energy harvesting unit and the storage battery, and performs connection processing with a connection request source according to a connection request.
  • a control device of a wireless network including a wireless node group operating in a first state to be performed and a second state in which a battery remaining amount of the storage battery can be recovered by the environmental power generation unit and which does not respond to the connection request, For each of the wireless nodes, a battery remaining value indicating the battery remaining capacity of the storage battery, a communication quality value indicating the communication quality with other wireless nodes in the vicinity, and information indicating the relay status or the non-relay status are stored.
  • a control unit that executes a process of transmitting an instruction to change to the first state to be performed.
  • the disconnection node can be properly reconnected.
  • FIG. 1 shows an example of a wireless sensor network (WSN) system according to an embodiment.
  • FIG. 2 shows a configuration example of a wireless communication node.
  • FIG. 3 shows a configuration example of the GW.
  • FIG. 4 shows an example of the configuration of the server.
  • FIG. 5 shows an example of the data structure of a table T1 storing the remaining battery capacity of each wireless communication node.
  • FIG. 6 shows an example of the data structure of a table T2 storing information indicating the communication quality (LQI) between each wireless communication node and the wireless communication node having the target ID.
  • FIG. 7 shows an example of the data structure of a table T3 storing information indicating the mode (state) of each wireless communication node.
  • FIG. 1 shows an example of a wireless sensor network (WSN) system according to an embodiment.
  • FIG. 2 shows a configuration example of a wireless communication node.
  • FIG. 3 shows a configuration example of the GW.
  • FIG. 4 shows an example of the configuration of the
  • FIG. 8 shows an example of the data structure of a table T4 storing the correspondence between cut nodes and lists of candidate nodes.
  • FIG. 9 shows an example of processing of the server at the normal time.
  • FIG. 10 shows an example of processing of the server at the time of detection of disconnection of a node.
  • FIG. 11 shows an example of processing of the server at the time of connection attempt with a non-relay node.
  • FIG. 12 shows an example of processing of the server at the time of connection attempt with a candidate node.
  • FIG. 13 shows operation 1 of scenario 1 in the specific example.
  • FIG. 14 shows operation 2 of scenario 1 in the specific example.
  • FIG. 15 shows operation 3 of scenario 1 in the specific example.
  • FIG. 16 shows operation 4 of scenario 1 in the specific example.
  • FIG. 17 shows operation 1 of scenario 2 in the specific example.
  • FIG. 18 shows operation 2 of scenario 2 in the specific example.
  • FIG. 19 shows operation 3 of scenario 2 in the specific example.
  • FIG. 20 shows operation 4 of scenario 2 in the specific example.
  • FIG. 21 shows an operation 5 of scenario 2 in the specific example.
  • FIG. 22 shows operation 5 of scenario 2 in the specific example.
  • FIG. 23 shows operation 6 of scenario 2 in the specific example.
  • FIG. 24 shows an operation 4 of scenario 3 in the specific example.
  • FIG. 25 shows operation 5 of scenario 3 in the specific example.
  • FIG. 26 shows an operation 5A of scenario 3 in the specific example.
  • FIG. 27 shows an operation 6 of scenario 3 in the specific example.
  • FIG. 28 shows an operation 7 of scenario 3 in the specific example.
  • FIG. 29 shows an operation 7 of scenario 3 in the specific example.
  • FIG. 1 shows an example of a wireless sensor network (WSN) system (communication system) according to an embodiment.
  • the WSN system includes a plurality of wireless communication nodes (also referred to as sensor nodes: simply described as “nodes”) 1, a gateway (GW) 2, and a server 4 connected via the GW 2 and the network 3.
  • a plurality of nodes 1 form a wireless network with the GW 2 at the top.
  • the node 1 is an example of the “wireless node”, and the plurality of nodes 1 is an example of the “node group”.
  • the node 1 has a sensor 17 (FIG. 2), and data (sensing data) obtained by the sensor 17 is transmitted to the GW 2 by multi-hop communication.
  • the GW 2 aggregates sensing data from the node 1 and sends it to the server 4 via the network 3.
  • the server 4 performs predetermined processing such as accumulation and analysis of sensing data.
  • the network 3 is, for example, a cellular network, an IP (Internet Protocol) network such as the Internet, or a combination of a cellular network and an IP network.
  • IP Internet Protocol
  • the configuration of the network 3 can be set as appropriate.
  • the node 1 is operable in a relay mode (relay state) for relaying communication (data) and a non-relay mode (non-relay state) for not relaying communication (data).
  • Node 1 in the non-relaying state is referred to as "non-relaying node”
  • node 1 in the relaying state is referred to as "relaying node”.
  • the relay state is an example of the “first state”
  • the non-relay state is an example of the “second state”.
  • the node 1 is set to one of the relay state and the non-relay state in the initial state, and is disposed at a predetermined position in the unconnected state.
  • the predetermined position is, for example, a position suitable for obtaining desired sensing data.
  • the unconnected node 1 performs the following initial setting. That is, the unconnected node 1 periodically transmits a search signal by broadcast. When receiving the search signal, the node 1 operating in the relay state transmits a search response to the node 1 that is the transmission source of the search signal. The node 1 that has received the search response transmits a connection request to the node 1 that has transmitted the search response. The node 1 having received the connection request returns a connection response to the node 1 which is the transmission source of the connection request. Thereby, the connection between the nodes 1 is established, and the state “not connected” of the node 1 transitions to the state “connected”.
  • the node 1 accepting the connection becomes a parent node to the node requesting the connection, and the node 1 requesting the connection becomes a child node to the parent node.
  • a parent node can have multiple child nodes.
  • GW2 may be a parent node.
  • the node 1 that has requested connection is a relay node
  • the node 1 (relay node) that has requested this connection will be in a state of accepting the unconnected node 1 in the vicinity thereof.
  • a tree having a top of GW2 as shown in FIG. 1 is constructed in the wireless network.
  • relay and “non-relay” are the operation modes of the node 1 to the last. Therefore, as shown in FIG. 1, even node 1 operating as a relay node may not have a child node.
  • the GW 2 is a communication device that performs near field communication used in the WSN system and relay of the network 3.
  • the GW 2 transmits sensing data sent from the node 1 to the server 4 via the network 3, and sends a control command for the node 1 sent from the server 4 to the node 1.
  • the sensing data and commands from the server 4 are routed along the network on the tree and delivered to the GW 2 or the destination node 1.
  • the short distance wireless communication is, for example, Bluetooth (registered trademark) or ZigBee. However, the communication standard is not limited to these examples.
  • FIG. 2 shows a configuration example of the wireless communication node (node 1).
  • the node 1 includes a power supply unit 1A and a control unit 1B.
  • Power supply unit 1A includes an environmental power generation element 11, a storage battery 12, and a power supply control circuit 13.
  • the environmental power generation element 11 is, for example, a solar cell, but may be one that generates power by photovoltaic power generation other than a solar battery, vibration power generation, or temperature difference power generation.
  • the environmental power generation element 11 is an example of the “environmental power generation unit”.
  • the control unit 1 B includes a central processing unit (CPU) 14, a read only memory (ROM) 15, a random access memory (RAM) 16, a sensor 17, and a wireless circuit 18 connected via a communication line (bus).
  • An antenna 19 is connected to the radio circuit 18.
  • the CPU 14 may be a microcontroller (MCU).
  • the power supply control circuit 13 supplies power to the control unit 1B and stores the surplus power in the storage battery 12 if the energy generating element 11 has a sufficient amount of power generation. When the power is insufficient, the power supply control circuit 13 compensates for the shortage from the storage battery 12 and supplies power to the control unit 1B.
  • the CPU 14 loads the program stored in the ROM 15 into the RAM 16 and executes the program to perform, for example, processing based on a command from the server 4 received from the wireless circuit 18.
  • processing based on a command for example, processing of changing the mode of node 1 from “relay” to “non-relay” or from “non-relay” to “relay” according to a command of mode change instruction I do.
  • the CPU 14 performs measurement of sensing data using the sensor 17, measurement of the remaining battery level of the storage battery 12, measurement of communication quality, and the like.
  • the CPU 21 transmits the result of each measurement via the wireless circuit 18.
  • the CPU 14 can measure the battery remaining amount by acquiring, for example, the terminal voltage of the storage battery 12 from the power supply control circuit 13. Also, the CPU 14 measures communication quality by acquiring from the wireless circuit 18 the radio wave intensity and the like when receiving radio waves transmitted by the peripheral node 1, for example. Therefore, the CPU 14 can measure the communication quality of the node 1 to which radio waves of receivable strength can be received regardless of the parent-child relationship.
  • FIG. 3 is a view showing a configuration example of the GW 2.
  • the GW 2 includes a CPU 21, a main storage device 22, an auxiliary storage device 23, a communication interface (communication IF) 24, and a wireless circuit 25 mutually connected via a communication line (bus).
  • An antenna 26 is connected to the wireless circuit 25.
  • the main storage device 22 is used as a program expansion area, a work area of the CPU 21, a storage area of data and programs, a buffer area of communication data, and the like.
  • the main storage device 22 is formed of, for example, a combination of a random access memory (RAM) and a RAM and a read only memory (ROM).
  • the auxiliary storage device 23 is used as a storage area for data and programs.
  • the auxiliary storage device 23 is formed of, for example, a non-volatile storage medium such as a hard disk drive (HDD), a solid state drive (SSD), a flash memory, and an electrically erasable programmable read-only memory (EEPROM).
  • the main storage device 22 and the auxiliary storage device 23 are examples of the “storage device”, the “storage medium”, the “memory”, and the “storage unit”.
  • the communication IF 24 is connected to the network 3 and used for communication with the server 4.
  • the communication IF 24 is, for example, a network interface card (NIC).
  • the CPU 21 operates as the GW 2 by executing a program stored in at least one of the main storage device 22 and the auxiliary storage device 23.
  • the CPU 21 performs processing for data relay to the server 4, such as protocol conversion for transmitting data and information received from each node 1 to the server 4 (network 3).
  • the CPU 21 performs processing for transmitting data (such as a command) received from the server 4 to the destination node 1.
  • the wireless circuit 25 is used for wireless communication between the GW 2 and each node 1.
  • FIG. 4 shows an exemplary configuration of the server 4.
  • the server 4 includes a CPU 41, a main storage device 42, an auxiliary storage device 43, and a communication IF 44 mutually connected via a communication line (bus).
  • the main storage unit 42, the auxiliary storage unit 43, and the communication IF 44 the same ones as the main storage unit 22, the auxiliary storage unit 23, and the communication IF 24 can be applied.
  • the communication IF 44 receives the data transmitted from the node 1, and the received data is stored in the auxiliary storage device 43.
  • the CPU 41 performs various processing as the server 4 by executing a program stored in at least one of the main storage device 42 and the auxiliary storage device 43.
  • the CPU 41 collects various information including sensing data from each node 1 at predetermined timing (for example, periodically or when an event occurs), and accumulates and processes the information.
  • the CPU 41 of the server 4 performs processing for periodically collecting the remaining battery level measured by each node 1 and the communication quality (LQI) generated based on radio waves received from peripheral nodes.
  • the CPU 41 performs processing for storing the collected information in at least one of the main storage device 42 and the auxiliary storage device 43.
  • the CPU 41 of the server 4 identifies the node 1 in the non-relaying state to be connected to the disconnection node, and transmits the change instruction to the relaying state to the identified node.
  • the above-described CPU 41 is an example of the “control device”, the “control unit”, and the “controller”.
  • the CPU 41 is also called an MPU (Microprocessor) or a processor.
  • the CPU 41 is not limited to a single processor, and may have a multiprocessor configuration. Also, a single CPU connected by a single socket may have a multi-core configuration. At least a part of the processing performed by the CPU 41 may be executed by a multi-core or multiple CPUs. At least a part of the processing performed by the CPU 41 is performed by a processor other than the CPU, for example, a dedicated processor such as a digital signal processor (DSP), a graphics processing unit (GPU), a numerical operation processor, a vector processor, or an image processor. Also good.
  • DSP digital signal processor
  • GPU graphics processing unit
  • numerical operation processor a vector processor
  • vector processor or an image processor. Also good.
  • the processing performed by the CPU 41 may be performed by an integrated circuit (IC) or another digital circuit.
  • the integrated circuit or the digital circuit may include an analog circuit.
  • the integrated circuit includes an LSI, an application specific integrated circuit (ASIC), and a programmable logic device (PLD).
  • the PLD includes a Field-Programmable Gate Array (FPGA).
  • At least part of the processing performed by the CPU 41 may be performed by a combination of a processor and an integrated circuit. The combination is called, for example, a microcontroller (MCU), a SoC (System-on-a-chip), a system LSI, a chipset, or the like.
  • FIG. 5 shows an example of the data structure of a table T1 storing information indicating the remaining battery capacity of each node.
  • FIG. 6 shows an example of the data structure of a table T2 storing information indicating communication quality (LQI) between each node and the node of the target ID.
  • FIG. 7 shows an example of the data structure of a table T3 storing information indicating the mode of each node.
  • the tables T1, T2 and T3 are stored in at least one of the main storage device 42 and the auxiliary storage device 43, and the reading and writing of data with respect to the tables T1, T2 and T3 are performed by the CPU 41. The same applies to a table T4 described later.
  • ID indicates the ID of the node 1 of the data transmission source, that is, the ID (identifier) of the node 1 that has measured the remaining battery level and the communication quality.
  • the “target ID” in FIG. 6 indicates a node 1 that is a transmission source node of radio waves when communication quality is measured.
  • Battery remaining amount in the table T1 is a value indicating the battery remaining amount (an example of the battery remaining amount value).
  • the value of the battery remaining amount may be a terminal voltage or a value obtained by converting the terminal voltage into a percentage.
  • “LQI” of the table T2 indicates a communication quality value (LQI value) obtained from the radio wave received from the node 1 having the target ID.
  • the table T3 stores information indicating whether the current mode of each node 1 is in the relay state or the non-relay state. As information stored in the table T3, when each node 1 is placed at a predetermined position, the initial state (one of “relay” and “non-relay”) of each node 1 is stored. Thereafter, each node 1 is updated each time the mode is switched.
  • the server 4 collects the remaining battery level of each node 1 and communication quality information (LQI) between the peripheral nodes, and predicts the remaining battery level of the relay node.
  • the server 4 transmits an instruction to change to the non-relay state to the relay node where the predicted remaining battery power falls below the predetermined threshold.
  • a relay node becomes a non-relay node by changing the mode to "non-relay".
  • the server 4 selects the node 1 to be changed to the relay state from the non-relay nodes around the node 1 to be changed to the non-relay node based on LQI, and instructs the selected node 1 to change to the relay state. send. This maintains the wireless network.
  • the node 1 connected (disposed) to the wireless network transmits an alive (Alive) signal by broadcast to the surroundings at regular intervals.
  • the node 1 assumes that the connection with the parent node is disconnected in the following cases, and transitions to the unconnected state.
  • (I) When the alive signal from the parent node can not be received for a certain period.
  • (Ii) When the communication quality (LQI) of the radio wave from the parent node becomes equal to or less than a preset communication quality threshold (communication quality threshold).
  • a preset communication quality threshold value a value indicating the minimum communication quality that can be stably communicated is determined in advance.
  • a notification indicating disconnection to all child nodes (disconnected notification before disconnected) Send).
  • the child node that has received the disconnection notification transmits a disconnection notification to the child node that it has, and transitions to the unconnected state.
  • the node 1 in the unconnected state searches for the parent node (GW 2 or connected relay node) of the reconnection destination in the same procedure as the initial setting, and when the connection with the parent node is completed, connection notification is sent to the server 4 Send.
  • GW 2 or connected relay node
  • the node 1 that has shifted to the unconnected state stops transmission of the alive signal.
  • the parent node monitors the alive signal periodically transmitted from the child node.
  • the parent node of the node 1 that has transitioned to the unconnected state detects the disconnection of the child node when the time when no alive signal from the child node is received exceeds the fixed period.
  • the parent node that has detected the disconnection of the child node transmits a disconnection detection notification to the server 4.
  • the server 4 detects the disconnection node which is the node 1 disconnected from the wireless network (parent node) by receiving the disconnection detection notification.
  • the server 4 having received the disconnection detection notification waits for the node 1 (node disconnected from the wireless network) corresponding to the disconnection detection notification and its descendant node 1 to connect to the node 1 other than the parent node for a certain period of time.
  • a period sufficient for the connection attempt is set based on the cycle in which the node 1 in the unconnected state transmits the search signal.
  • the server 4 performs the following processing on the node 1 (disconnected node) that does not transition to the connected state. That is, the server 4 extracts a non-relay node having a remaining battery capacity and communication quality capable of properly communicating with the disconnection node, based on the communication quality and the battery remaining capacity related to the disconnection node recorded in the table T1 and the table T2. Do.
  • the communication quality between the disconnection node and the non-relay node is equal to or higher than the threshold of the communication quality
  • the battery remaining amount of the non-relay node is equal to or higher than the battery remaining amount threshold
  • extract nodes recorded as non-relay nodes as the battery remaining capacity threshold value, a value of the remaining battery capacity sufficient to operate stably as a relay node is used.
  • the server 4 transmits a command to change the mode to “relay” to the extracted non-relay node.
  • the disconnect node becomes connected and transmits a connection notification to the server 4.
  • the server 4 can consider that the disconnection node is connected by receiving the connection notification.
  • the server 4 When all of the disconnected nodes are in the connected state, and after waiting for a sufficient period to make a connection attempt, the server 4 performs the following processing. That is, the server 4 transmits a command for returning, to the non-relay node, the node 1 which is not connected to the disconnection node among the nodes 1 changed to the relay node. Also, the server 4 records the node 1 to which the disconnection node is connected as a relay node in the table T3 and leaves the node 1 as the relay node.
  • the priority may be determined in the order of the remaining amount of remaining battery and in the order of high communication quality, and node 1 extracted according to the priority may be changed to relay nodes one by one to perform connection trial. .
  • the server 4 performs the following processing. That is, a non-relay node whose communication quality with the disconnection node exceeds the communication quality threshold (is in the vicinity of the disconnection node) and the remaining battery amount is less than the remaining battery threshold (less than the predetermined amount) Determine a candidate node for.
  • Information on candidate nodes is stored, for example, in a table T4 shown in FIG.
  • the table T4 stores a list of candidate node IDs corresponding to the disconnected node IDs.
  • the server 4 performs a mode for this node 1 Send a command to change to "relay".
  • the server 4 receives the connection notification from the disconnection node, it records the node 1 whose mode has been changed to “relay” as the relay node in the table T3 and also lists the candidate nodes related to the disconnection node that received the connection notification. Erase from T4. If the connection notification can not be received even after a sufficient time for connection attempt, the server 4 transmits a command to change the mode of the node 1 having changed the mode to "relay” to "non-relay” .
  • FIG. 9 shows an example of processing of the server at the normal time.
  • the process shown in FIG. 9 is performed, for example, periodically. However, it may be implemented in response to some trigger (event occurrence).
  • the server 4 collects data from all the nodes 1 forming the wireless network. Data to be collected includes sensing data, battery remaining capacity, and communication quality (LQI). The remaining battery level is stored in table T1, and the communication quality (LQI) is stored in table T2.
  • the node 1 measures the remaining battery level and the LQI according to the data collection cycle regardless of whether the mode is relay or non-relay.
  • the data to be collected may be transmitted by the node 1 in response to a request from the server 4 or may be transmitted voluntarily by the node 1 at a fixed time.
  • the server 4 determines whether the candidate node recorded in the table T4 is included in the data transmission source. If it is determined that there is no candidate node, the process proceeds to 003, and waits until the next cycle (a cycle for collecting the remaining battery capacity and the communication quality). On the other hand, when it is determined that there is a candidate node, the server 4 tries to connect the candidate node and the disconnection node. Thereafter, the process proceeds to 003.
  • the server 4 sends a command to the candidate node to change the candidate node into a relay node so that the disconnection node is connected to the relay node. After that, when receiving the connection notification from the disconnection node, the server 4 records the node 1 whose mode has been changed to “relay” in the table T3 and deletes the candidate node relating to the disconnection node from the table T4. If the connection notification can not be received from the disconnection node even after a sufficient time for connection attempt, the server 4 transmits a command to return the mode of the relay node to “non-relay” to the relay node.
  • FIG. 10 shows an example of processing of the server at the time of detection of disconnection of a node.
  • the processing for FIG. 10 is performed on node 1 (node 1 disconnected from the wireless network) corresponding to the disconnection detection notification and its descendant node 1.
  • the disconnection detection notification includes the ID of the child node whose parent node has detected disconnection and its descendant nodes, and the server 4 can recognize the node or node group disconnected from the tree.
  • Each process (operation) illustrated in FIG. 10 may be executed for each disconnected node 1 (disconnected node), or may be executed collectively for a plurality of disconnected nodes 1 of each operation.
  • the following description exemplifies the processing for one node 1 corresponding to the disconnection detection notification.
  • the server 4 waits for the node 1 corresponding to the disconnection detection notification to connect to the node 1 other than the parent node for a certain period (011). If the connection notification can be received from the node 1 within a predetermined period (Yes in 012), the processing in FIG. 10 ends. On the other hand, when the connection notification can not be received from the node 1 even after the predetermined period has elapsed (No in 012), the process proceeds to 013.
  • the server 4 refers to the tables T1, T2 and T3 and the communication quality with the node 1 exceeds the communication quality threshold and the battery remaining capacity exceeds the battery remaining capacity threshold, and the mode is “non-relay” Extract (specify) node 1 of.
  • a process of trying to connect the non-relay node extracted in 013 with the node 1 is performed. That is, the server 4 changes the non-relay node to a relay node, and waits for reception of a connection notification indicating that the node 1 has connected to the relay node for a certain period.
  • connection notification it is determined whether or not the connection is successful. If the connection notification can be received within a certain period, it is determined that the server is successful (Yes in 015), and if not, it is determined that failure (No in 015).
  • the server 4 refers to the tables T1, T2 and T3 and the battery remaining amount is less than the battery remaining amount threshold (or less) and the communication quality is not higher than the communication quality threshold.
  • the relay node is extracted (specified) (016).
  • the server 4 records the non-relay node extracted at 016 in the table T4 as a candidate node for the node 1 (disconnected node) (017). Thereafter, the process of FIG. 10 ends.
  • FIG. 11 shows a processing example of the server at the time of connection attempt with a non-relay node, and shows details of the processing of 014. The process of FIG. 11 is performed for each disconnected node.
  • the server 4 transmits an instruction to change to the relay state (an instruction to change the mode to “relay”) to the non-relay node extracted in 016.
  • the server 4 stands by for a fixed period. In 023, the server 4 determines whether the disconnection node is connected within a predetermined period, that is, whether the connection notification from the disconnection node is received. If it is determined that the disconnection node is connected, the processing proceeds to 024, and if not, the processing proceeds to 025.
  • the server 4 sets the content of the mode of the connection destination node 1 of the disconnection node to “relay” in the table T3. That is, the server 4 changes the content of the information indicating the relay state or the non-relay state to the relay state.
  • the connection notification includes the ID of the node 1 of the connection destination, and in the table T3, the mode corresponding to the ID is set to "relay". This makes it possible to avoid contradiction between the mode (state) of the actual node 1 and the mode (state) of the node 1 managed by the server 4.
  • the server 4 transmits a command for returning the node 1 that has been changed to the relay state in the process of 021 to the non-relay state. Thereafter, the process of FIG. 11 ends.
  • the CPU 41 (control unit) of the server 4 does not receive the connection notification indicating the connection between the node 1 changed to the relay state by the change instruction and the disconnected node, the node 1 changed to the relay state To send a change instruction to change the state to the non-relay state. In this way, by returning the node 1 to the non-relaying state, it is possible to avoid contradiction between the mode (state) of the actual node 1 and the mode (state) of the node 1 managed by the server 4 it can. In addition, when the battery level is not full, the battery level can be recovered.
  • FIG. 12 shows an example of processing of the server at the time of connection attempt with a candidate node, and shows details of the processing of 004 of FIG.
  • the process of FIG. 12 is started on the occasion of updating of the tables T1 and T2 (updating of the remaining battery amount) which is periodically performed, as also shown in FIG.
  • the server 4 selects a candidate node whose battery remaining capacity exceeds the battery remaining capacity threshold from the list (table T4) of candidate nodes corresponding to the disconnection node.
  • the server 4 determines at 031 whether or not the candidate node could be selected. If it is determined that the candidate node has been selected, the process proceeds to 033. If not, the process of FIG. 12 ends.
  • the server 4 deletes the node 1 (referred to as a selected node) selected from the list from the list of candidate nodes.
  • the server 4 transmits an instruction to change to the relay mode to the selected node.
  • the server 4 waits for a fixed period of time to wait for reception of the connection notification.
  • the server 4 determines whether or not the disconnection node has connected to the selected node (whether or not a connection notification has been received). If it is determined that the disconnection node is connected to the selected node, the process proceeds to 037. If not, the process proceeds to 039.
  • the server 4 deletes the list of candidate nodes (all candidate nodes) corresponding to the connection node (the node 1 connected to the selection node and having transmitted the connection notification).
  • the server 4 stores the mode "relay" of the selected node in the table T3.
  • the server 4 transmits a change instruction to the non-relay state to the selected node. Thereafter, the process of FIG. 12 ends.
  • FIG. 13 shows a communication system according to scenario 1.
  • the wireless network is formed by the GW 2 and the ten nodes 1.
  • the wireless network has a tree in which GW2 is a vertex, and a node 1 (denoted as “node # 1”) with number “1” is connected to GW2, and a tree in which node 1 (node # 2) with number “2” is connected to GW2 And are formed.
  • node # 8 which is a child node of node # 4 connected to node # 1.
  • the node # 8 determines that the node # 4 is disconnected (considered).
  • the node # 4 detects the disconnection of the node # 8 which is a child node, since the alive signal is not received from the node # 8 for a certain period of time.
  • the node # 4 transmits a disconnection detection notification to the server 4.
  • the disconnection detection notification is received by the server 4 via the nodes # 1 and GW2.
  • the server 4 receives the disconnection detection notification and starts the processing shown in FIG.
  • node # 8 (disconnected node) disconnected from node # 4 broadcasts a message (signal) of a reconnection request around node # 8.
  • the server 4 waits for reception of a connection notification indicating that the node # 8 is connected to the node 1 other than the node # 4 for a certain period of time.
  • the node # 8 performs a reconnection procedure with the node 1 (the node 1 selected according to a predetermined priority in the case of a plurality of nodes 1) having received the connection response and reconnects.
  • the priority is determined based on, for example, the order of early reception of connection responses, the order of good communication quality, and the like.
  • the reconnection procedure is performed according to an existing procedure such as, for example, the procedure defined in IEEE 802.15.4.
  • the node # 8 performs a reconnection procedure with the node # 5 and connects to the node # 5.
  • Node # 8 sends a connection notification.
  • the connection notification reaches the server 4 through the node # 5, the node # 2, and the GW2.
  • the server 4 that has received the connection notification can receive the connection notification within a predetermined period, and thus ends the processing illustrated in FIG.
  • FIG. 17 shows a communication system according to scenario 2.
  • the tree configuration of the wireless network is the same as that of FIG. 13 (scenario 1).
  • node # 5, node # 7, node # 8, node # 9 and node # 10 are non-relay nodes (node 1 in non-relay state).
  • the node # 8 (disconnected node) disconnected from the node # 4 transmits a message (signal) of a reconnection request by broadcast around the node # 8.
  • the server 4 waits for reception of a connection notification indicating that the node # 8 is connected to the node 1 other than the node # 4 for a certain period of time.
  • the server 4 refers to the table T1, the table T2 and the table T3.
  • the server 4 refers to the table T3 to identify the node 1 in the non-relay state. As a result, node # 7, node # 5, node # 9, and node # 10 are identified.
  • the server 4 extracts, from the tables T1 and T2, the remaining battery capacities of the node # 7, the node # 5, the node # 9, and the node # 10, and the LQI in the case of using the node # 8 as the target ID.
  • the value measured before node # 8 is disconnected is used as the value of LQI.
  • the server 4 has the battery remaining charge threshold “15” and the communication quality threshold “10”. In this case, the server 4 extracts the node # 5 and the node # 9 as non-relay nodes in which the battery remaining amount and the LQI each exceed the corresponding threshold.
  • the server 4 transmits a change instruction to the relay state to the node # 5 and the node # 9 extracted in the operation 4 and stands by for a certain period (021 and 022 in FIG. 11).
  • the node # 8 can receive connection responses from the nodes # 5 and # 9.
  • the node # 8 performs a reconnection procedure with the node # 5 selected from the node # 5 and the node # 9, and connects to the node # 5.
  • the server 4 receives the connection notification from the node # 8.
  • the change instruction to the non-relaying state is transmitted to the server 4 that has received the connection notification and the node 1 (node # 9) other than the connection destination node 1 (node # 5).
  • node # 9 enters the non-relay state.
  • FIG. 24 shows an operation 4 of scenario 3.
  • the operations 1, 2, and 3 of the scenario 3 are the same as the operations 1 to 3 (FIGS. 17 to 19) of the scenario 2, and thus the description thereof is omitted.
  • the server 4 performs the processing from 013 onward in FIG. 10, and refers to the tables T1 to T3 to extract nonrelay nodes whose battery remaining amount and LQI with the node # 8 exceed the threshold.
  • the server 4 extracts the node # 5, the node # 7, and the node # 9 as a non-relay node in which the battery remaining amount does not exceed the threshold but the LQI exceeds the threshold.
  • the server 4 records the IDs of the nodes # 5, # 7, and # 9 in the list (table T4) of candidate nodes corresponding to the ID of the node # 8.
  • the server 4 periodically collects data including the remaining battery charge from each node 1 including the candidate node. If the battery remaining amount of the candidate node does not exceed the battery remaining amount threshold, the server 4 does not perform any particular processing.
  • the server 4 deletes the node # 5 and the node # 9 from the list of candidate nodes in the table T4, and transmits an instruction to change to the relay state to the node # 5 and the node # 9.
  • the node # 5 and the node # 9 enter the relay state (relay node) in response to the change instruction.
  • the node # 8 receives connection responses from the nodes # 5 and # 9 by transmitting the reconnection request. Then, as shown in FIG. 28, the node # 8 performs a reconnection procedure with the node # 5 selected from the node # 5 and the node # 9, connects to the node # 5, and transmits a connection notification to the server 4 .
  • the server 4 having received the connection notification transmits a change instruction to the non-relaying state to the node # 9, and changes the node # 9 to the non-relaying state. Further, the candidate node corresponding to the node # 8 is deleted from the table T4, and the node # 7 is removed from the candidate nodes. The node # 7 is treated as a non-relay node before being extracted as a candidate node.
  • the wireless network includes a node group (a plurality of nodes 1) in which each node 1 has the following configuration.
  • the environmental power generation element 11 and the storage battery 12 are provided.
  • It can be driven by receiving the power of at least one of the environmental power generation element 11 and the storage battery 12.
  • the first state (relay state) in which connection processing with the connection request source is performed in response to the connection request, and the battery power of the storage battery 12 can be recovered by the environmental power generation element 11 and does not respond to the connection request It operates in the second state (non-relaying state).
  • the server 4 operates as a control device of the wireless network.
  • the GW 2 operates as a relay device that relays communication between the control device and the wireless node.
  • Each node 1 forming the wireless network periodically measures the remaining battery level and the communication quality with the peripheral nodes, and transmits the measurement result to the server 4 via the GW 2.
  • the server 4 periodically collects information indicating the remaining battery level of each node 1 and the communication quality with the peripheral nodes, and stores the information in the table T1 and the table T2.
  • the server 4 also manages the mode (relay or non-relay) of each node 1 using the table T3.
  • Extract node 1 of The extracted node 1 is a non-relaying node 1 (non-relaying node) having communication quality connectable to the disconnection node and having the remaining battery capacity changeable to the relaying state.
  • the server 4 changes the extracted non-relay node to the relay state, and performs a connection attempt (that is, to test whether the disconnected node is connected to the node 1 (wireless network) changed to the relay state by the reconnection procedure). .
  • the node 1 changed to the relay state responds to the connection request from the disconnection node and performs reconnection processing, whereby the disconnection node is connected with the appropriate node 1 (having suitable battery remaining capacity and communication quality). , Can be reconnected to the wireless network.
  • the server 4 When the disconnection node is not connected to the node 1 (wireless network) changed to the relay state by the connection attempt, the server 4 returns the node 1 changed to the relay state to the non-relay state. This is to eliminate the contradiction between the relay and non-relay states managed in the table T4.
  • the server 4 extracts candidate nodes and stores them in the table T4.
  • the candidate node has communication quality connectable to the disconnection node (LQI with the disconnection node exceeds the threshold) but the remaining battery capacity is not sufficient to change to the relay state (non-remaining battery capacity does not meet the threshold) non It is node 1 in the relay state.
  • the server 4 relays the mode of the candidate node when the battery remaining amount of the candidate node reaches the value that can be changed to the relay state (value exceeding the threshold) at the time of periodical table T1 (battery remaining amount) update. Change to and try to connect.
  • the appropriate non-relay node having suitable battery remaining capacity and communication quality
  • the relay node and reconnected Can be done. That is, it becomes possible to maintain a wireless network.
  • the server 4 operates as a control device of a wireless network controlling the mode (relay / non-relay) of each node 1
  • the GW 2 may operate as a control device of the wireless network. That is, the control device of the wireless network may be implemented in a collection device (server 4) for collecting data transmitted from each node 1, and a relay device for relaying data transmitted from each node 1 to the collection device (GW2) may be implemented.
  • the CPU 21 of the GW 2 When the GW 2 operates as a control device of a wireless network, the CPU 21 of the GW 2 performs the processing (the processing illustrated in FIGS. 9 to 12) that the CPU 41 of the server 4 is performing.
  • Tables T1 to T4 are stored in at least one of the main storage device 22 and the auxiliary storage device 23 of the GW2. The configurations described in the embodiments are examples and can be combined as appropriate.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

A control device for a wireless network including a group of wireless nodes that each receive and are driven by electrical power from at least one of an energy harvesting unit and a storage battery, and that each operate in a first state, in which a connection process with a connection request source is performed in response to a connection request, and a second state, in which the remaining charge of the storage battery can be replenished by the energy harvesting unit and connection requests are not responded to. The control device for a wireless network stores, for each wireless node, a remaining charge value for the storage battery, a communication quality value for communication with another wireless node in the vicinity, and information indicating either the first or the second state, and when a disconnected node is detected, the control device specifies a wireless node in the second state, said wireless node having a remaining charge value and a communication quality value for communication with the disconnected node that surpass respective threshold values, and transmits instructions to change the specified wireless node in the second state to the first state, in which the connection process with the disconnected node is performed.

Description

無線網の制御装置，無線網の制御方法，及び通信システムWireless network control device, wireless network control method, and communication system
　本発明は、無線網の制御装置，無線網の制御方法，及び通信システムに関する。 The present invention relates to a control device for a radio network, a control method for a radio network, and a communication system.
　近年、太陽光などの環境発電で動作する無線通信ノードにセンサを接続し、マルチホップ通信でセンシング情報を収集するワイヤレスセンサネットワーク(ＷＳＮ)システムが提案されている。センシングデータはマルチホップ通信でゲートウェイ(ＧＷ)に集約され、ＧＷからインターネットを経由してサーバに蓄積される。 BACKGROUND In recent years, a wireless sensor network (WSN) system has been proposed in which a sensor is connected to a wireless communication node operating by environmental power generation such as sunlight and the sensing information is collected by multi-hop communication. The sensing data is aggregated in a gateway (GW) by multi-hop communication, and is accumulated in the server from the GW via the Internet.
　マルチホップ通信を行う無線通信ノードは、通信の中継を行う中継状態と、通信の中継を行わない非中継状態とで動作する。非中継状態の無線通信ノード（非中継ノードと呼ぶ）は中継動作を行わない。無線通信ノードが中継ノードとして動作するか非中継ノードとして動作するかは、無線通信ノードの動作設定により行われる。 A wireless communication node performing multi-hop communication operates in a relay state in which communication is relayed and in a non-relay state in which communication is not relayed. A wireless communication node in a non-relay state (referred to as a non-relay node) does not perform a relay operation. Whether the wireless communication node operates as a relay node or as a non-relay node is determined by the operation setting of the wireless communication node.
　中継ノードの消費電力は非中継ノードの消費電力より大きい。このため、同条件で運用しても中継ノードの電池残量が非中継ノードの電池残量が枯渇する前に枯渇する可能性がある。そこで、以下のような技術がある。 The power consumption of the relay node is greater than the power consumption of the non-relay node. For this reason, even when operating under the same conditions, the remaining battery power of the relay node may be exhausted before the remaining battery power of the non-relay node is exhausted. Therefore, there are the following technologies.
　例えば、サーバ側で各ノードの電池残量と周辺ノードとの通信品質情報（ＬＱＩ：Link Quality Indicator）を収集する。中継ノードの電池残量を予測し、電池残量が枯渇する前にサーバからの指示で中継ノードを非中継ノードに変更し、環境発電による電池残量の回復を図る。また、非中継ノードに変更する中継ノード周辺の非中継ノードをＬＱＩに基づいてサーバ側で選定して中継ノードに変更するよう指示することでネットワークを維持する（例えば、特許文献１を参照）。 For example, the server side collects communication quality information (LQI: Link Quality Indicator) between the remaining battery level of each node and the peripheral nodes. The remaining battery capacity of the relay node is predicted, and the relay node is changed to a non-relay node according to an instruction from the server before the remaining battery power is exhausted, and the remaining battery power is recovered by environmental power generation. In addition, a non-relay node around the relay node to be changed to a non-relay node is selected on the server side based on LQI, and the network is maintained by instructing the relay node to change (see, for example, Patent Document 1).
国際公開第２０１６／１１３８８４号International Publication No. 2016/113884 特開２００７－０３６４２３号公報JP 2007-036423 A 特開２００９－１１１４５５号公報JP, 2009-111455, A
　上述した無線通信ノードを含む無線網でマルチホップ通信を行う場合に、電池残量が低下した無線通信ノードを非中継ノードに変更して電池残量を回復させる運用が考えられる。この場合に以下のような問題が生じるおそれがあった。 When multi-hop communication is performed in a wireless network including the above-described wireless communication node, it is conceivable to change the wireless communication node whose battery remaining capacity is reduced to a non-relay node to recover the battery remaining capacity. In this case, the following problems may occur.
　無線通信環境の悪化などの理由により、無線通信ノードが無線網から切断され、未接続状態となることがある。この場合、未接続状態の無線通信ノードは、接続要求を送信する。このとき、接続要求を受信した無線通信ノードが中継状態であれば接続要求に応じて接続要求元との接続を行い、非中継状態であれば電池残量回復のために接続要求に応じない運用とすることが考えられる。 The wireless communication node may be disconnected from the wireless network and not connected due to deterioration of the wireless communication environment or the like. In this case, the wireless communication node in the unconnected state transmits a connection request. At this time, if the wireless communication node receiving the connection request is in the relay state, the connection with the connection request source is made in response to the connection request, and if it is in the non-relay state, the operation is not performed It is possible to do.
　ところが、接続要求を受信可能な範囲にある無線通信ノードの全てが非中継状態であると、接続要求に応じる無線通信ノードが存在しない状態となる。このため、未接続状態の無線通信ノードが無線網に接続できない状態となる。 However, if all the wireless communication nodes in the range capable of receiving the connection request are in the non-relaying state, there will be no wireless communication node responding to the connection request. Therefore, the wireless communication node in the unconnected state can not connect to the wireless network.
　本発明は、切断ノードの再接続を適正に行うことのできる無線網の制御装置、無線網の制御方法，及び通信システムを提供することを目的とする。 An object of the present invention is to provide a control apparatus for a wireless network, a control method for a wireless network, and a communication system capable of properly performing reconnection of a disconnection node.
　一つの態様は、各無線ノードが環境発電部と蓄電池とを有し、前記環境発電部及び前記蓄電池の少なくとも一方の電力を受けて駆動し、接続要求に応じて接続要求元との接続処理を行う第１の状態と、前記環境発電部により前記蓄電池の電池残量を回復可能であり、前記接続要求に応じない第２の状態とで動作する無線ノード群を含む無線網の制御装置において、
　前記各無線ノードについて、前記蓄電池の電池残量を示す電池残量値と、周辺にある他の無線ノードとの通信品質を示す通信品質値と、中継状態か非中継状態かを示す情報を記憶する記憶部と、
　前記無線網から切断された前記無線ノード群中の無線ノードである切断ノードを検出した場合に、前記記憶部の参照によって電池残量値が電池残量閾値を上回るとともに前記切断ノードとの通信品質値が通信品質閾値を上回る前記第２の状態の無線ノードを特定する処理と、特定した前記第２の状態の無線ノードを前記切断ノードからの接続要求に応じて前記切断ノードとの接続処理を行う前記第１の状態に変更する指示を送信する処理とを実行する制御部と
を含む無線網の制御装置である。 In one aspect, each wireless node includes an energy harvesting unit and a storage battery, receives and drives power of at least one of the energy harvesting unit and the storage battery, and performs connection processing with a connection request source according to a connection request. In a control device of a wireless network including a wireless node group operating in a first state to be performed and a second state in which a battery remaining amount of the storage battery can be recovered by the environmental power generation unit and which does not respond to the connection request,
For each of the wireless nodes, a battery remaining value indicating the battery remaining capacity of the storage battery, a communication quality value indicating the communication quality with other wireless nodes in the vicinity, and information indicating the relay status or the non-relay status are stored. A storage unit to
When a disconnected node which is a wireless node in the wireless node group disconnected from the wireless network is detected, the battery remaining amount value exceeds the battery remaining amount threshold by referring to the storage unit and the communication quality with the disconnected node is detected. A process of identifying a wireless node in the second state whose value exceeds the communication quality threshold; and a process of connecting the identified wireless node in the second state to the disconnect node in response to a connection request from the disconnect node And a control unit that executes a process of transmitting an instruction to change to the first state to be performed.
　一側面では、切断ノードの再接続を適正に行うことができる。 In one aspect, the disconnection node can be properly reconnected.
図１は実施形態に係るワイヤレスセンサネットワーク（ＷＳＮ）システムの例を示す。FIG. 1 shows an example of a wireless sensor network (WSN) system according to an embodiment. 図２は無線通信ノードの構成例を示す。FIG. 2 shows a configuration example of a wireless communication node. 図３はＧＷの構成例を示す。FIG. 3 shows a configuration example of the GW. 図４はサーバの構成例を示す。FIG. 4 shows an example of the configuration of the server. 図５は各無線通信ノードの電池残量を記憶するテーブルＴ１のデータ構造例を示す。FIG. 5 shows an example of the data structure of a table T1 storing the remaining battery capacity of each wireless communication node. 図６は各無線通信ノードと対象ＩＤを有する無線通信ノードとの通信品質（ＬＱＩ）を示す情報を記憶するテーブルＴ２のデータ構造例を示す。FIG. 6 shows an example of the data structure of a table T2 storing information indicating the communication quality (LQI) between each wireless communication node and the wireless communication node having the target ID. 図７は各無線通信ノードのモード（状態）を示す情報を記憶するテーブルＴ３のデータ構造例を示す。FIG. 7 shows an example of the data structure of a table T3 storing information indicating the mode (state) of each wireless communication node. 図８は切断ノードと候補ノードのリストとの対応関係を記憶するテーブルＴ４のデータ構造例を示す。FIG. 8 shows an example of the data structure of a table T4 storing the correspondence between cut nodes and lists of candidate nodes. 図９は通常時におけるサーバの処理例を示す。FIG. 9 shows an example of processing of the server at the normal time. 図１０はノードの切断検出時におけるサーバの処理例を示す。FIG. 10 shows an example of processing of the server at the time of detection of disconnection of a node. 図１１は非中継ノードとの接続試行時におけるサーバの処理例を示す。FIG. 11 shows an example of processing of the server at the time of connection attempt with a non-relay node. 図１２は候補ノードとの接続試行時におけるサーバの処理例を示す。FIG. 12 shows an example of processing of the server at the time of connection attempt with a candidate node. 図１３は具体例におけるシナリオ１の動作１を示す。FIG. 13 shows operation 1 of scenario 1 in the specific example. 図１４は具体例におけるシナリオ１の動作２を示す。FIG. 14 shows operation 2 of scenario 1 in the specific example. 図１５は具体例におけるシナリオ１の動作３を示す。FIG. 15 shows operation 3 of scenario 1 in the specific example. 図１６は具体例におけるシナリオ１の動作４を示す。FIG. 16 shows operation 4 of scenario 1 in the specific example. 図１７は具体例におけるシナリオ２の動作１を示す。FIG. 17 shows operation 1 of scenario 2 in the specific example. 図１８は具体例におけるシナリオ２の動作２を示す。FIG. 18 shows operation 2 of scenario 2 in the specific example. 図１９は具体例におけるシナリオ２の動作３を示す。FIG. 19 shows operation 3 of scenario 2 in the specific example. 図２０は具体例におけるシナリオ２の動作４を示す。FIG. 20 shows operation 4 of scenario 2 in the specific example. 図２１は具体例におけるシナリオ２の動作５を示す。FIG. 21 shows an operation 5 of scenario 2 in the specific example. 図２２は具体例におけるシナリオ２の動作５を示す。FIG. 22 shows operation 5 of scenario 2 in the specific example. 図２３は具体例におけるシナリオ２の動作６を示す。FIG. 23 shows operation 6 of scenario 2 in the specific example. 図２４は具体例におけるシナリオ３の動作４を示す。FIG. 24 shows an operation 4 of scenario 3 in the specific example. 図２５は具体例におけるシナリオ３の動作５を示す。FIG. 25 shows operation 5 of scenario 3 in the specific example. 図２６は具体例におけるシナリオ３の動作５Ａを示す。FIG. 26 shows an operation 5A of scenario 3 in the specific example. 図２７は具体例におけるシナリオ３の動作６を示す。FIG. 27 shows an operation 6 of scenario 3 in the specific example. 図２８は具体例におけるシナリオ３の動作７を示す。FIG. 28 shows an operation 7 of scenario 3 in the specific example. 図２９は具体例におけるシナリオ３の動作７を示す。FIG. 29 shows an operation 7 of scenario 3 in the specific example.
　以下、図面を参照して、実施形態に係る無線網の制御装置，無線網の制御方法，及び通信システムについて説明する。実施形態の構成は例示であり、本発明は実施形態の構成に限定されない。 Hereinafter, a control apparatus for a wireless network, a control method for a wireless network, and a communication system according to an embodiment will be described with reference to the drawings. The configuration of the embodiment is an exemplification, and the present invention is not limited to the configuration of the embodiment.
　＜ＷＳＮシステム＞
　図１は実施形態に係るワイヤレスセンサネットワーク（ＷＳＮ）システム（通信システム）の例を示す。ＷＳＮシステムは、複数の無線通信ノード（センサノードともいう：単に「ノード」と表記）１と、ゲートウェイ（ＧＷ）２と、ＧＷ２とネットワーク３を介して接続されるサーバ４とを含む。複数のノード１によってＧＷ２を頂点とする無線網が形成される。ノード１は「無線ノード」の一例であり、複数のノード１は「ノード群」の一例である。 <WSN system>
FIG. 1 shows an example of a wireless sensor network (WSN) system (communication system) according to an embodiment. The WSN system includes a plurality of wireless communication nodes (also referred to as sensor nodes: simply described as “nodes”) 1, a gateway (GW) 2, and a server 4 connected via the GW 2 and the network 3. A plurality of nodes 1 form a wireless network with the GW 2 at the top. The node 1 is an example of the “wireless node”, and the plurality of nodes 1 is an example of the “node group”.
　ノード１はセンサ１７（図２）を有し、センサ１７によって得られたデータ（センシングデータ）は、マルチホップ通信でＧＷ２に送信される。ＧＷ２はノード１からのセンシングデータの集約を行い、ネットワーク３を介してサーバ４へ送る。サーバ４は、センシングデータの蓄積、解析等、所定の処理を行う。 The node 1 has a sensor 17 (FIG. 2), and data (sensing data) obtained by the sensor 17 is transmitted to the GW 2 by multi-hop communication. The GW 2 aggregates sensing data from the node 1 and sends it to the server 4 via the network 3. The server 4 performs predetermined processing such as accumulation and analysis of sensing data.
　ネットワーク３は、例えば、セルラー網，インターネットなどのＩＰ（Internet Protocol）網，セルラー網とＩＰ網との組み合わせなどである。但し、センシングデータをサーバ４へ送信できる限り、ネットワーク３の構成は適宜設定可能である。 The network 3 is, for example, a cellular network, an IP (Internet Protocol) network such as the Internet, or a combination of a cellular network and an IP network. However, as long as the sensing data can be transmitted to the server 4, the configuration of the network 3 can be set as appropriate.
　ノード１は、通信（データ）の中継を行う中継モード（中継状態）と、通信（データ）の中継を行わない非中継モード（非中継状態）とで動作可能である。非中継状態のノード１を「非中継ノード」と呼び、中継状態のノード１を「中継ノード」と呼ぶ。中継状態は「第１の状態」の一例であり、非中継状態は「第２の状態」の一例である。 The node 1 is operable in a relay mode (relay state) for relaying communication (data) and a non-relay mode (non-relay state) for not relaying communication (data). Node 1 in the non-relaying state is referred to as "non-relaying node", and node 1 in the relaying state is referred to as "relaying node". The relay state is an example of the “first state”, and the non-relay state is an example of the “second state”.
　ノード１は、初期状態において、中継状態及び非中継状態の一方に設定されるとともに、未接続状態で、所定の位置に配置される。所定の位置は、例えば所望のセンシングデータを得るのに適した位置である。 The node 1 is set to one of the relay state and the non-relay state in the initial state, and is disposed at a predetermined position in the unconnected state. The predetermined position is, for example, a position suitable for obtaining desired sensing data.
　未接続状態のノード１は、次のような初期設定を行う。すなわち、未接続状態のノード１は、定期的に探索信号をブロードキャストで発信する。中継状態で動作するノード１は探索信号を受信すると、探索信号の送信元のノード１へ探索応答を送信する。探索応答を受信したノード１は、探索応答の送信元のノード１に接続要求を送信する。接続要求を受信したノード１は接続要求の送信元のノード１へ接続応答を返す。これにより、ノード１間の接続が確立し、ノード１の状態“未接続”が状態“接続済み”に遷移する。 The unconnected node 1 performs the following initial setting. That is, the unconnected node 1 periodically transmits a search signal by broadcast. When receiving the search signal, the node 1 operating in the relay state transmits a search response to the node 1 that is the transmission source of the search signal. The node 1 that has received the search response transmits a connection request to the node 1 that has transmitted the search response. The node 1 having received the connection request returns a connection response to the node 1 which is the transmission source of the connection request. Thereby, the connection between the nodes 1 is established, and the state “not connected” of the node 1 transitions to the state “connected”.
　接続を確立した二つのノード１のうち、接続を受け入れたノード１が接続を要求したノードに対する親ノードとなり、接続を要求したノード１は親ノードに対する子ノードになる。親ノードは複数の子ノードを持つことができる。ＧＷ２が親ノードになる場合もある。 Of the two nodes 1 establishing a connection, the node 1 accepting the connection becomes a parent node to the node requesting the connection, and the node 1 requesting the connection becomes a child node to the parent node. A parent node can have multiple child nodes. GW2 may be a parent node.
　接続を要求したノード１が中継ノードである場合には、この接続を要求したノード１（中継ノード）は、その周辺にある未接続状態のノード１を受け入れる状態となる。このようなノード１間の接続が繰り返されることによって、図１に示すようなＧＷ２を頂点としたツリーが無線網に構築される。 If the node 1 that has requested connection is a relay node, the node 1 (relay node) that has requested this connection will be in a state of accepting the unconnected node 1 in the vicinity thereof. By repeating the connection between such nodes 1, a tree having a top of GW2 as shown in FIG. 1 is constructed in the wireless network.
　なお、「中継」及び「非中継」はあくまでもノード１の動作モードである。このため、図１に示すように、中継ノードとして動作するノード１であっても子ノードを持たないこともある。 Note that “relay” and “non-relay” are the operation modes of the node 1 to the last. Therefore, as shown in FIG. 1, even node 1 operating as a relay node may not have a child node.
　ＧＷ２はＷＳＮシステムで使用される近距離無線通信とネットワーク３の中継を行う通信機器である。ＧＷ２は、ノード１から送られてきたセンシングデータをサーバ４へネットワーク３を介して送信したり、サーバ４から送られてきたノード１の制御用のコマンドをノード１へ送信したりする。センシングデータやサーバ４からのコマンドなどは、ツリー上のネットワークに沿ってルーティングされ、ＧＷ２或いは宛先のノード１に届けられる。なお、近距離無線通信は、例えばBluetooth（登録商標）やZigBeeなどである。但し、通信規格はこれらの例示に制限されない。 The GW 2 is a communication device that performs near field communication used in the WSN system and relay of the network 3. The GW 2 transmits sensing data sent from the node 1 to the server 4 via the network 3, and sends a control command for the node 1 sent from the server 4 to the node 1. The sensing data and commands from the server 4 are routed along the network on the tree and delivered to the GW 2 or the destination node 1. The short distance wireless communication is, for example, Bluetooth (registered trademark) or ZigBee. However, the communication standard is not limited to these examples.
　＜無線通信ノードの構成例＞
　図２は無線通信ノード（ノード１）の構成例を示す。ノード１は、電源部１Ａと制御部１Ｂとを含む。電源部１Ａは、環境発電素子１１と、蓄電池１２と、電源制御回路１３とを含む。環境発電素子１１は、例えば太陽電池であるが、太陽電池以外の光発電、振動発電や温度差発電によって発電するものであっても良い。環境発電素子１１は「環境発電部」の一例である。 <Configuration Example of Wireless Communication Node>
FIG. 2 shows a configuration example of the wireless communication node (node 1). The node 1 includes a power supply unit 1A and a control unit 1B. Power supply unit 1A includes an environmental power generation element 11, a storage battery 12, and a power supply control circuit 13. The environmental power generation element 11 is, for example, a solar cell, but may be one that generates power by photovoltaic power generation other than a solar battery, vibration power generation, or temperature difference power generation. The environmental power generation element 11 is an example of the “environmental power generation unit”.
　制御部１Ｂは、通信線（バス）を介して接続されたCentral Processing Unit（ＣＰＵ）１４，Read Only Memory（ＲＯＭ）１５，Random Access Memory（ＲＡＭ）１６，センサ１７，無線回路１８を含む。無線回路１８にはアンテナ１９が接続されている。ＣＰＵ１４はマイクロコントローラ（ＭＣＵ）でも良い。 The control unit 1 B includes a central processing unit (CPU) 14, a read only memory (ROM) 15, a random access memory (RAM) 16, a sensor 17, and a wireless circuit 18 connected via a communication line (bus). An antenna 19 is connected to the radio circuit 18. The CPU 14 may be a microcontroller (MCU).
　電源部１Ａでは、電源制御回路１３が環境発電素子１１に十分な発電量があれば制御部１Ｂに電源供給するとともに余剰電力を蓄電池１２に蓄電する。電力が不足する場合は電源制御回路１３は蓄電池１２から足りない分を補って制御部１Ｂに電源供給を行う。 In the power supply unit 1A, the power supply control circuit 13 supplies power to the control unit 1B and stores the surplus power in the storage battery 12 if the energy generating element 11 has a sufficient amount of power generation. When the power is insufficient, the power supply control circuit 13 compensates for the shortage from the storage battery 12 and supplies power to the control unit 1B.
　制御部１Ｂでは、ＣＰＵ１４がＲＯＭ１５に記録されたプログラムをＲＡＭ１６にロードして実行することで、例えば、無線回路１８から受信されたサーバ４からのコマンドに基づく処理を行う。コマンドに基づく処理として、例えば、モードの変更指示のコマンドに応じて、ノード１のモードを「中継」から「非中継」に変更したり、「非中継」から「中継」に変更したりする処理を行う。或いはプログラムの実行によって、ＣＰＵ１４は、センサ１７を用いたセンシングデータの測定、蓄電池１２の電池残量の測定、通信品質の測定等を行う。ＣＰＵ２１は、各測定の結果を無線回路１８を介して送信する。 In the control unit 1 </ b> B, the CPU 14 loads the program stored in the ROM 15 into the RAM 16 and executes the program to perform, for example, processing based on a command from the server 4 received from the wireless circuit 18. As processing based on a command, for example, processing of changing the mode of node 1 from “relay” to “non-relay” or from “non-relay” to “relay” according to a command of mode change instruction I do. Alternatively, by executing the program, the CPU 14 performs measurement of sensing data using the sensor 17, measurement of the remaining battery level of the storage battery 12, measurement of communication quality, and the like. The CPU 21 transmits the result of each measurement via the wireless circuit 18.
　ＣＰＵ１４は、例えば蓄電池１２の端子電圧などを電源制御回路１３から取得することで、電池残量を測定することができる。また、ＣＰＵ１４は、例えば、周辺のノード１が発信した電波を受けた時の電波強度などを無線回路１８から取得することで通信品質を測定する。このため、ＣＰＵ１４は、受信可能な強度の電波が届くノード１の通信品質を親子関係の有無に関わらず測定することができる。 The CPU 14 can measure the battery remaining amount by acquiring, for example, the terminal voltage of the storage battery 12 from the power supply control circuit 13. Also, the CPU 14 measures communication quality by acquiring from the wireless circuit 18 the radio wave intensity and the like when receiving radio waves transmitted by the peripheral node 1, for example. Therefore, the CPU 14 can measure the communication quality of the node 1 to which radio waves of receivable strength can be received regardless of the parent-child relationship.
　＜ＧＷの構成＞
　図３はＧＷ２の構成例を示す図である。ＧＷ２は、通信線（バス）を介して相互に接続されたＣＰＵ２１，主記憶装置２２，補助記憶装置２３，及び通信インタフェース（通信ＩＦ）２４，無線回路２５を含む。無線回路２５にはアンテナ２６が接続されている。 <Configuration of GW>
FIG. 3 is a view showing a configuration example of the GW 2. The GW 2 includes a CPU 21, a main storage device 22, an auxiliary storage device 23, a communication interface (communication IF) 24, and a wireless circuit 25 mutually connected via a communication line (bus). An antenna 26 is connected to the wireless circuit 25.
　主記憶装置２２はプログラムの展開領域、ＣＰＵ２１の作業領域、データやプログラムの記憶領域、通信データのバッファ領域などとして使用される。主記憶装置２２は、例えばRandom Access Memory（ＲＡＭ）、ＲＡＭとRead Only Memory（ＲＯＭ）との組み合わせで形成される。 The main storage device 22 is used as a program expansion area, a work area of the CPU 21, a storage area of data and programs, a buffer area of communication data, and the like. The main storage device 22 is formed of, for example, a combination of a random access memory (RAM) and a RAM and a read only memory (ROM).
　補助記憶装置２３はデータやプログラムの記憶領域として使用される。補助記憶装置２３は、例えば、ハードディスクドライブ（ＨＤＤ）、Solid State Drive（ＳＳＤ）、フラッシュメモリ、Electrically Erasable Programmable Read-Only Memory（ＥＥＰＲＯＭ）などの不揮発性記憶媒体で形成される。主記憶装置２２及び補助記憶装置２３のそれぞれは、「記憶装置」、「記憶媒体」、「メモリ」、「記憶部」の一例である。 The auxiliary storage device 23 is used as a storage area for data and programs. The auxiliary storage device 23 is formed of, for example, a non-volatile storage medium such as a hard disk drive (HDD), a solid state drive (SSD), a flash memory, and an electrically erasable programmable read-only memory (EEPROM). The main storage device 22 and the auxiliary storage device 23 are examples of the “storage device”, the “storage medium”, the “memory”, and the “storage unit”.
　通信ＩＦ２４は、ネットワーク３と接続され、サーバ４との通信に使用される。通信ＩＦ２４は例えばネットワークインタフェースカード（ＮＩＣ）である。ＣＰＵ２１は、主記憶装置２２及び補助記憶装置２３の少なくとも一方に記憶されたプログラムを実行することによって、ＧＷ２としての動作を行う。例えば、ＣＰＵ２１は、各ノード１から受信されるデータや情報をサーバ４（ネットワーク３）へ送信するためのプロトコル変換等、サーバ４へのデータ中継のための処理などを行う。或いは、ＣＰＵ２１は、サーバ４から受信されたデータ（コマンドなど）を、宛先のノード１へ送信する処理を行う。無線回路２５は、ＧＷ２と各ノード１との無線通信に使用される。 The communication IF 24 is connected to the network 3 and used for communication with the server 4. The communication IF 24 is, for example, a network interface card (NIC). The CPU 21 operates as the GW 2 by executing a program stored in at least one of the main storage device 22 and the auxiliary storage device 23. For example, the CPU 21 performs processing for data relay to the server 4, such as protocol conversion for transmitting data and information received from each node 1 to the server 4 (network 3). Alternatively, the CPU 21 performs processing for transmitting data (such as a command) received from the server 4 to the destination node 1. The wireless circuit 25 is used for wireless communication between the GW 2 and each node 1.
　＜サーバの構成＞
　図４はサーバ４の構成例を示す。図４に示すように、サーバ４は、通信線（バス）を介して相互に接続されたＣＰＵ４１，主記憶装置４２，補助記憶装置４３，通信ＩＦ４４を含む。主記憶装置４２，補助記憶装置４３，通信ＩＦ４４として主記憶装置２２，補助記憶装置２３，通信ＩＦ２４と同様のものを適用できる。通信ＩＦ４４は、ノード１から送信されたデータを受信し、受信されたデータは補助記憶装置４３に記憶される。 <Server configuration>
FIG. 4 shows an exemplary configuration of the server 4. As shown in FIG. 4, the server 4 includes a CPU 41, a main storage device 42, an auxiliary storage device 43, and a communication IF 44 mutually connected via a communication line (bus). As the main storage unit 42, the auxiliary storage unit 43, and the communication IF 44, the same ones as the main storage unit 22, the auxiliary storage unit 23, and the communication IF 24 can be applied. The communication IF 44 receives the data transmitted from the node 1, and the received data is stored in the auxiliary storage device 43.
　ＣＰＵ４１は、主記憶装置４２及び補助記憶装置４３の少なくとも一方に記憶されたプログラムを実行することによって、サーバ４としての様々な処理を行う。例えば、ＣＰＵ４１は、所定のタイミング（例えば、定期的に、或いはイベント発生時に）で、各ノード１からセンシングデータを含む様々な情報を収集し、情報の蓄積や加工を行う。 The CPU 41 performs various processing as the server 4 by executing a program stored in at least one of the main storage device 42 and the auxiliary storage device 43. For example, the CPU 41 collects various information including sensing data from each node 1 at predetermined timing (for example, periodically or when an event occurs), and accumulates and processes the information.
　実施形態に係るサーバ４のＣＰＵ４１は、各ノード１で測定される電池残量と周辺ノードから受信される電波に基づき生成される通信品質（ＬＱＩ）とを定期的に収集する処理を行う。ＣＰＵ４１は、収集した情報を主記憶装置４２及び補助記憶装置４３の少なくとも一方に記憶する処理を行う。サーバ４のＣＰＵ４１は、切断ノードの検出時に、切断ノードと接続させる非中継状態のノード１を特定し、特定したノードへ中継状態への変更指示を送信する処理を行う。 The CPU 41 of the server 4 according to the embodiment performs processing for periodically collecting the remaining battery level measured by each node 1 and the communication quality (LQI) generated based on radio waves received from peripheral nodes. The CPU 41 performs processing for storing the collected information in at least one of the main storage device 42 and the auxiliary storage device 43. When detecting the disconnection node, the CPU 41 of the server 4 identifies the node 1 in the non-relaying state to be connected to the disconnection node, and transmits the change instruction to the relaying state to the identified node.
　なお、上記したＣＰＵ４１は、「制御装置」、「制御部」、「コントローラ」の一例である。ＣＰＵ４１は、ＭＰＵ（Microprocessor）、プロセッサとも呼ばれる。ＣＰＵ４１は、単一のプロセッサに限定される訳ではなく、マルチプロセッサ構成であってもよい。また、単一のソケットで接続される単一のＣＰＵがマルチコア構成を有していても良い。ＣＰＵ４１で行われる処理の少なくとも一部は、マルチコア又は複数のＣＰＵで実行されても良い。ＣＰＵ４１で行われる処理の少なくとも一部は、ＣＰＵ以外のプロセッサ、例えば、Digital Signal Processor(ＤＳＰ)、Graphics Processing Unit（ＧＰＵ）、数値演算プロセッサ、ベクトルプロセッサ、画像処理プロセッサ等の専用プロセッサで行われても良い。 The above-described CPU 41 is an example of the “control device”, the “control unit”, and the “controller”. The CPU 41 is also called an MPU (Microprocessor) or a processor. The CPU 41 is not limited to a single processor, and may have a multiprocessor configuration. Also, a single CPU connected by a single socket may have a multi-core configuration. At least a part of the processing performed by the CPU 41 may be executed by a multi-core or multiple CPUs. At least a part of the processing performed by the CPU 41 is performed by a processor other than the CPU, for example, a dedicated processor such as a digital signal processor (DSP), a graphics processing unit (GPU), a numerical operation processor, a vector processor, or an image processor. Also good.
　また、ＣＰＵ４１によって行われる処理の少なくとも一部は、集積回路（ＩＣ）、その他のディジタル回路で行われても良い。また、集積回路やディジタル回路はアナログ回路を含んでいても良い。集積回路は、ＬＳＩ、Application Specific Integrated Circuit（ＡＳＩＣ）、プログラマブルロジックデバイス（ＰＬＤ）を含む。ＰＬＤは、Field-Programmable Gate Array(ＦＰＧＡ)を含む。ＣＰＵ４１で行われる処理の少なくとも一部は、プロセッサと集積回路との組み合わせにより実行されても良い。組み合わせは、例えば、マイクロコントローラ（ＭＣＵ）、ＳｏＣ（System-on-a-chip）、システムＬＳＩ、チップセットなどと呼ばれる。 In addition, at least part of the processing performed by the CPU 41 may be performed by an integrated circuit (IC) or another digital circuit. In addition, the integrated circuit or the digital circuit may include an analog circuit. The integrated circuit includes an LSI, an application specific integrated circuit (ASIC), and a programmable logic device (PLD). The PLD includes a Field-Programmable Gate Array (FPGA). At least part of the processing performed by the CPU 41 may be performed by a combination of a processor and an integrated circuit. The combination is called, for example, a microcontroller (MCU), a SoC (System-on-a-chip), a system LSI, a chipset, or the like.
　＜テーブルの構成＞
　図５は各ノードの電池残量を示す情報を記憶するテーブルＴ１のデータ構造例を示す。図６は各ノードと対象ＩＤのノードとの通信品質（ＬＱＩ）を示す情報を記憶するテーブルＴ２のデータ構造例を示す。図７は、各ノードのモードを示す情報を記憶するテーブルＴ３のデータ構造例を示す。テーブルＴ１,Ｔ２及びＴ３は主記憶装置４２及び補助記憶装置４３の少なくとも一方に記憶され、テーブルＴ１,Ｔ２及びＴ３に対するデータの読み書きはＣＰＵ４１によって行われる。なお、後述するテーブルＴ４も同様である。 <Table configuration>
FIG. 5 shows an example of the data structure of a table T1 storing information indicating the remaining battery capacity of each node. FIG. 6 shows an example of the data structure of a table T2 storing information indicating communication quality (LQI) between each node and the node of the target ID. FIG. 7 shows an example of the data structure of a table T3 storing information indicating the mode of each node. The tables T1, T2 and T3 are stored in at least one of the main storage device 42 and the auxiliary storage device 43, and the reading and writing of data with respect to the tables T1, T2 and T3 are performed by the CPU 41. The same applies to a table T4 described later.
　図５及び図６に示すテーブルＴ１及びテーブルＴ２において、「ＩＤ」は、データの送信元のノード１のＩＤ、つまり電池残量や通信品質の測定を行ったノード１のＩＤ（識別子）を示す。図６の「対象ＩＤ」は通信品質を測定したときの電波の送信元ノードであるノード１を指す。 In the tables T1 and T2 shown in FIGS. 5 and 6, “ID” indicates the ID of the node 1 of the data transmission source, that is, the ID (identifier) of the node 1 that has measured the remaining battery level and the communication quality. . The “target ID” in FIG. 6 indicates a node 1 that is a transmission source node of radio waves when communication quality is measured.
　テーブルＴ１の「電池残量」は、電池残量を示す値（電池残量値の一例）である。電池残量の値は、端子電圧でも良く、端子電圧を百分率に換算した値でも良い。テーブルＴ２の「ＬＱＩ」は、対象ＩＤを有するノード１からの受信電波から求めた通信品質値（ＬＱＩ値）を示す。 "Battery remaining amount" in the table T1 is a value indicating the battery remaining amount (an example of the battery remaining amount value). The value of the battery remaining amount may be a terminal voltage or a value obtained by converting the terminal voltage into a percentage. “LQI” of the table T2 indicates a communication quality value (LQI value) obtained from the radio wave received from the node 1 having the target ID.
　テーブルＴ３は、各ノード１の現在のモードが中継状態と非中継状態とのいずれであるかを示す情報を記憶する。テーブルＴ３に記憶される情報として、各ノード１が所定位置に配置された時点では、各ノード１の初期状態（「中継」及び「非中継」の一方）が記憶される。その後、各ノード１がモードを切り替える毎に更新される。 The table T3 stores information indicating whether the current mode of each node 1 is in the relay state or the non-relay state. As information stored in the table T3, when each node 1 is placed at a predetermined position, the initial state (one of “relay” and “non-relay”) of each node 1 is stored. Thereafter, each node 1 is updated each time the mode is switched.
　＜動作例＞
　以下、動作例を説明する。前提として、サーバ４による各ノード１のモード制御について説明する。サーバ４は、各ノード１の電池残量と周辺ノードとの通信品質情報（ＬＱＩ）を収集し、中継ノードの電池残量を予測する。予測された電池残量が所定の閾値を下回る中継ノードに対し、サーバ４は非中継状態への変更指示を送信する。中継ノードはモードを「非中継」に変更することで非中継ノードとなる。 <Operation example>
Hereinafter, an operation example will be described. As a premise, mode control of each node 1 by the server 4 will be described. The server 4 collects the remaining battery level of each node 1 and communication quality information (LQI) between the peripheral nodes, and predicts the remaining battery level of the relay node. The server 4 transmits an instruction to change to the non-relay state to the relay node where the predicted remaining battery power falls below the predetermined threshold. A relay node becomes a non-relay node by changing the mode to "non-relay".
　非中継状態では消費電力が抑えられ、環境発電素子１１で発電された電力を蓄電池１２に蓄電可能な状態となる。これによって電池残量の回復が図られる。また、サーバ４は、非中継ノードに変更されるノード１の周辺にある非中継ノードから中継状態へ変更させるノード１をＬＱＩに基づいて選択し、選択したノード１へ中継状態への変更指示を送る。これによって、無線網を維持する。 In the non-relay state, the power consumption is suppressed, and the power generated by the energy harvesting element 11 can be stored in the storage battery 12. As a result, the battery level can be recovered. Further, the server 4 selects the node 1 to be changed to the relay state from the non-relay nodes around the node 1 to be changed to the non-relay node based on LQI, and instructs the selected node 1 to change to the relay state. send. This maintains the wireless network.
　動作例として、ノード１が切断された場合の動作について説明する。無線網に接続（配置）されたノード１は、一定間隔でアライブ（Alive）信号をブロードキャストで周囲に送信する。ノード１は、以下の場合に親ノードとの接続が切断されたとみなし、未接続状態に遷移する。
（ｉ）親ノードからのアライブ信号が一定期間受信できない場合。
（ｉｉ）親ノードからの電波の通信品質（ＬＱＩ）が予め設定された通信品質の閾値（通信品質閾値）以下になった場合。
　通信品質閾値として、安定して通信可能な最低限の通信品質を示す値が予め決定される。 As an operation example, an operation when the node 1 is disconnected will be described. The node 1 connected (disposed) to the wireless network transmits an alive (Alive) signal by broadcast to the surroundings at regular intervals. The node 1 assumes that the connection with the parent node is disconnected in the following cases, and transitions to the unconnected state.
(I) When the alive signal from the parent node can not be received for a certain period.
(Ii) When the communication quality (LQI) of the radio wave from the parent node becomes equal to or less than a preset communication quality threshold (communication quality threshold).
As the communication quality threshold value, a value indicating the minimum communication quality that can be stably communicated is determined in advance.
　親ノードとの接続が切断されたと判定したノード１（切断ノードと称する）が子ノードを有する場合には、未接続状態になる前に、全ての子ノードに対し、切断を示す通知（切断通知）を送信する。切断通知を受信した子ノードは、自身が有する子ノードに切断通知を送信し、未接続状態に遷移する。 If the node 1 (referred to as a disconnected node) determined to have disconnected from the parent node has a child node, a notification indicating disconnection to all child nodes (disconnected notification before disconnected) Send). The child node that has received the disconnection notification transmits a disconnection notification to the child node that it has, and transitions to the unconnected state.
　未接続状態になったノード１は、初期設定と同じ手順で再接続先の親ノード（ＧＷ２又は接続済みの中継ノード）を探索し、親ノードとの接続が完了すると、サーバ４に接続通知を送信する。 The node 1 in the unconnected state searches for the parent node (GW 2 or connected relay node) of the reconnection destination in the same procedure as the initial setting, and when the connection with the parent node is completed, connection notification is sent to the server 4 Send.
　未接続状態に遷移したノード１はアライブ信号の送信を停止する。親ノードは子ノードから定期的に送信されるアライブ信号を監視している。未接続状態に遷移したノード１の親ノードは、子ノードからのアライブ信号を受信されない時間が一定期間を超えることを以て、子ノードの切断を検出する。子ノードの切断を検出した親ノードは、サーバ４に切断検出通知を送信する。 The node 1 that has shifted to the unconnected state stops transmission of the alive signal. The parent node monitors the alive signal periodically transmitted from the child node. The parent node of the node 1 that has transitioned to the unconnected state detects the disconnection of the child node when the time when no alive signal from the child node is received exceeds the fixed period. The parent node that has detected the disconnection of the child node transmits a disconnection detection notification to the server 4.
　サーバ４は、切断検出通知を受信することで無線網（親ノード）から切断されたノード１である切断ノードを検出する。切断検出通知を受信したサーバ４は、切断検出通知に対応するノード１（無線網から切断されたノード）およびその子孫のノード１が親ノード以外のノード１に接続するのを一定期間待つ。一定期間として、未接続状態のノード１が探索信号を送信する周期に基づいて接続試行を行うのに十分な期間が設定される。 The server 4 detects the disconnection node which is the node 1 disconnected from the wireless network (parent node) by receiving the disconnection detection notification. The server 4 having received the disconnection detection notification waits for the node 1 (node disconnected from the wireless network) corresponding to the disconnection detection notification and its descendant node 1 to connect to the node 1 other than the parent node for a certain period of time. As the fixed period, a period sufficient for the connection attempt is set based on the cycle in which the node 1 in the unconnected state transmits the search signal.
　一定期間が経過しても接続状態に遷移しない（接続通知を受信できない）ノード１がある場合、サーバ４は、接続状態に遷移しないノード１（切断ノード）に関して以下の処理を行う。すなわち、サーバ４は、テーブルＴ１及びテーブルＴ２に記録された切断ノードに係る通信品質及び電池残量に基づいて、切断ノードと適正に通信可能な電池残量及び通信品質を有する非中継ノードを抽出する。 If there is a node 1 that does not transition to the connected state (cannot receive the connection notification) even after a certain period of time passes, the server 4 performs the following processing on the node 1 (disconnected node) that does not transition to the connected state. That is, the server 4 extracts a non-relay node having a remaining battery capacity and communication quality capable of properly communicating with the disconnection node, based on the communication quality and the battery remaining capacity related to the disconnection node recorded in the table T1 and the table T2. Do.
　具体的には、サーバ４は、切断ノードと当該非中継ノードとの通信品質が通信品質の閾値以上であり、当該非中継ノードの電池残量が電池残量の閾値（電池残量閾値）以上であり、さらに非中継ノードとして記録されているノードを抽出する。ここで、電池残量閾値として、中継ノードとして安定して動作するのに十分な電池残量の値が使用される。 Specifically, in the server 4, the communication quality between the disconnection node and the non-relay node is equal to or higher than the threshold of the communication quality, and the battery remaining amount of the non-relay node is equal to or higher than the battery remaining amount threshold And extract nodes recorded as non-relay nodes. Here, as the battery remaining capacity threshold value, a value of the remaining battery capacity sufficient to operate stably as a relay node is used.
　接続可能な非中継ノードを抽出すると、サーバ４は、抽出した非中継ノードに対し、モードを「中継」に変更するコマンドを送信する。非中継ノードが中継ノードとなり、切断ノードが中継ノードに接続すると、切断ノードは接続状態となり、接続通知をサーバ４に送信する。サーバ４は、接続通知の受信によって、切断ノードが接続されたとみなすことができる。 When the connectable non-relay node is extracted, the server 4 transmits a command to change the mode to “relay” to the extracted non-relay node. When the non-relay node becomes a relay node and the disconnect node connects to the relay node, the disconnect node becomes connected and transmits a connection notification to the server 4. The server 4 can consider that the disconnection node is connected by receiving the connection notification.
　切断ノードの全てが接続状態となった場合、及び接続試行を行うのに十分な期間を待機した後に、サーバ４は以下のような処理を行う。すなわち、サーバ４は、中継ノードに変更したノード１のうち切断ノードが接続しなかったノード１を非中継ノードに戻すコマンドを送信する。また、サーバ４は、切断ノードが接続したノード１は中継ノードとしてテーブルＴ３に記録して中継ノードのままにする。 When all of the disconnected nodes are in the connected state, and after waiting for a sufficient period to make a connection attempt, the server 4 performs the following processing. That is, the server 4 transmits a command for returning, to the non-relay node, the node 1 which is not connected to the disconnection node among the nodes 1 changed to the relay node. Also, the server 4 records the node 1 to which the disconnection node is connected as a relay node in the table T3 and leaves the node 1 as the relay node.
　なお、上記した動作例では、抽出したノード１のモードを一斉に「中継」に変更する例を説明した。これに代えて、例えば電池残量の多い順や通信品質が高い順などの優先順位を決定し、優先順位に従って抽出したノード１を１つずつ中継ノードへ変更し、接続試行を行っても良い。 In the above-described operation example, the example in which the modes of the extracted node 1 are simultaneously changed to "relay" has been described. Instead of this, for example, the priority may be determined in the order of the remaining amount of remaining battery and in the order of high communication quality, and node 1 extracted according to the priority may be changed to relay nodes one by one to perform connection trial. .
　接続可能な非中継ノードが抽出できない場合、接続試行を行っても切断ノードが残る場合には、サーバ４は以下の処理を行う。すなわち、切断ノードとの通信品質が通信品質閾値を上回り（切断ノードの周辺にいる）で、かつ、電池残量が電池残量閾値未満（所定量に満たない）の非中継ノードを、切断ノードに対する候補ノードに決定する。候補ノードの情報は、例えば、図８に示すテーブルＴ４に記憶される。テーブルＴ４は、切断ノードのＩＤに対応する、候補ノードのＩＤのリストを記憶する。 If the connectable non-relay node can not be extracted, and if the disconnected node remains even after the connection attempt, the server 4 performs the following processing. That is, a non-relay node whose communication quality with the disconnection node exceeds the communication quality threshold (is in the vicinity of the disconnection node) and the remaining battery amount is less than the remaining battery threshold (less than the predetermined amount) Determine a candidate node for. Information on candidate nodes is stored, for example, in a table T4 shown in FIG. The table T4 stores a list of candidate node IDs corresponding to the disconnected node IDs.
　サーバ４は、電池残量を受信したノード１が候補ノードとしてテーブルＴ４に記録されており、かつ、受信した電池残量が電池残量閾値を上回っている場合は、このノード１に対し、モードを「中継」に変更するコマンドを送信する。 If the node 1 that has received the remaining battery power is recorded as a candidate node in the table T4 and the received remaining battery power exceeds the remaining battery power threshold, the server 4 performs a mode for this node 1 Send a command to change to "relay".
　その後、サーバ４は切断ノードからの接続通知を受け取った場合は、モードを「中継」に変更したノード１を中継ノードとしてテーブルＴ３に記録するとともに、接続通知を受け取った切断ノードに関する候補ノードをテーブルＴ４から消去する。接続試行を行うのに十分な時間が経過しても接続通知を受信できなかった場合は、サーバ４はモードを「中継」に変更したノード１のモードを「非中継」に戻すコマンドを送信する。 Thereafter, when the server 4 receives the connection notification from the disconnection node, it records the node 1 whose mode has been changed to “relay” as the relay node in the table T3 and also lists the candidate nodes related to the disconnection node that received the connection notification. Erase from T4. If the connection notification can not be received even after a sufficient time for connection attempt, the server 4 transmits a command to change the mode of the node 1 having changed the mode to "relay" to "non-relay" .
　＜サーバにおける処理＞
　次に、サーバにおける処理について図９～図１２を用いて説明する。図９～図１２の処理は、例えばサーバ４のＣＰＵ４１によって行われる。図９は通常時におけるサーバの処理例を示す。 <Process on server>
Next, processing in the server will be described using FIG. 9 to FIG. The processing of FIGS. 9 to 12 is performed by, for example, the CPU 41 of the server 4. FIG. 9 shows an example of processing of the server at the normal time.
　図９に示す処理は、例えば、定期的に行われる。但し、何らかのトリガ（イベント発生）に応じて実施される場合もあり得る。００１において、サーバ４は、無線網を形成する全てのノード１からデータ収集を行う。収集対象のデータは、センシングデータ，電池残量，通信品質（ＬＱＩ）を含む。電池残量はテーブルＴ１に、通信品質（ＬＱＩ）はテーブルＴ２に記憶される。ノード１は、モードが中継か非中継かに関わらず、データ収集の周期に応じて電池残量及びＬＱＩの測定を行う。収集対象のデータは、サーバ４からの要求に応じてノード１が送信しても良く、ノード１が定時に自発的に送信しても良い。 The process shown in FIG. 9 is performed, for example, periodically. However, it may be implemented in response to some trigger (event occurrence). At 001, the server 4 collects data from all the nodes 1 forming the wireless network. Data to be collected includes sensing data, battery remaining capacity, and communication quality (LQI). The remaining battery level is stored in table T1, and the communication quality (LQI) is stored in table T2. The node 1 measures the remaining battery level and the LQI according to the data collection cycle regardless of whether the mode is relay or non-relay. The data to be collected may be transmitted by the node 1 in response to a request from the server 4 or may be transmitted voluntarily by the node 1 at a fixed time.
　００２では、サーバ４は、データの送信元にテーブルＴ４に記録された候補ノードが含まれているか否かを判定する。候補ノードがないと判定される場合には、処理が００３に進み、次回の周期（電池残量や通信品質を収集する周期）まで待機する。これに対し、候補ノードがあると判定される場合には、サーバ４は候補ノードと切断ノードとの接続試行を行う。その後、処理が００３に進む。 At 002, the server 4 determines whether the candidate node recorded in the table T4 is included in the data transmission source. If it is determined that there is no candidate node, the process proceeds to 003, and waits until the next cycle (a cycle for collecting the remaining battery capacity and the communication quality). On the other hand, when it is determined that there is a candidate node, the server 4 tries to connect the candidate node and the disconnection node. Thereafter, the process proceeds to 003.
　００３では、上述したように、サーバ４は候補ノードにコマンドを送って候補ノードを中継ノードに変更し、切断ノードが中継ノードに接続するようにする。その後、切断ノードからの接続通知を受信した場合、サーバ４はモードを「中継」に変更したノード１をテーブルＴ３に記録し、切断ノードに関する候補ノードをテーブルＴ４から消去する。接続試行を行うのに十分な時間が経過しても切断ノードから接続通知を受信できなかった場合は、サーバ４は中継ノードのモードを「非中継」に戻すコマンドを中継ノードに送信する。 At 003, as described above, the server 4 sends a command to the candidate node to change the candidate node into a relay node so that the disconnection node is connected to the relay node. After that, when receiving the connection notification from the disconnection node, the server 4 records the node 1 whose mode has been changed to “relay” in the table T3 and deletes the candidate node relating to the disconnection node from the table T4. If the connection notification can not be received from the disconnection node even after a sufficient time for connection attempt, the server 4 transmits a command to return the mode of the relay node to “non-relay” to the relay node.
　図１０はノードの切断検出時におけるサーバの処理例を示す。図１０に対する処理は、切断検出通知に対応するノード１（無線網から切断されたノード１）およびその子孫のノード１を対象に行われる。例えば、切断検出通知には、親ノードが切断を検出した子ノード及びその子孫ノードのＩＤを含み、ツリーから切断されたノード又はノード群をサーバ４が認識可能となっている。 FIG. 10 shows an example of processing of the server at the time of detection of disconnection of a node. The processing for FIG. 10 is performed on node 1 (node 1 disconnected from the wireless network) corresponding to the disconnection detection notification and its descendant node 1. For example, the disconnection detection notification includes the ID of the child node whose parent node has detected disconnection and its descendant nodes, and the server 4 can recognize the node or node group disconnected from the tree.
　図１０に示す各処理（オペレーション）は、切断されたノード１（切断ノード）毎に実行されても良く、各オペレーションが切断された複数のノード１に対してまとめて実行されても良い。以下の説明は、切断検出通知に対応する１つのノード１に関する処理を例示する。 Each process (operation) illustrated in FIG. 10 may be executed for each disconnected node 1 (disconnected node), or may be executed collectively for a plurality of disconnected nodes 1 of each operation. The following description exemplifies the processing for one node 1 corresponding to the disconnection detection notification.
　０１１では、サーバ４は切断検出通知に対応するノード１が親ノード以外のノード１に接続するのを一定期間待つ（０１１）。一定期間内にノード１から接続通知を受信できた場合には（０１２のＹｅｓ）、図１０の処理が終了する。これに対し、一定期間が経過してもノード１から接続通知を受信できない場合には（０１２のＮｏ）、処理が０１３に進む。 At 011, the server 4 waits for the node 1 corresponding to the disconnection detection notification to connect to the node 1 other than the parent node for a certain period (011). If the connection notification can be received from the node 1 within a predetermined period (Yes in 012), the processing in FIG. 10 ends. On the other hand, when the connection notification can not be received from the node 1 even after the predetermined period has elapsed (No in 012), the process proceeds to 013.
　０１３では、サーバ４は、テーブルＴ１，テーブルＴ２，及びテーブルＴ３を参照し、ノード１との通信品質が通信品質閾値を上回るとともに電池残量が電池残量閾値を上回り、モードが「非中継」のノード１を抽出（特定）する。 In 013, the server 4 refers to the tables T1, T2 and T3 and the communication quality with the node 1 exceeds the communication quality threshold and the battery remaining capacity exceeds the battery remaining capacity threshold, and the mode is “non-relay” Extract (specify) node 1 of.
　０１４では、０１３で抽出された非中継ノードとノード１との接続を試行する処理を行う。すなわち、サーバ４は、非中継ノードを中継ノードに変更し、ノード１が中継ノードと接続した旨の接続通知の受信を一定期間待つ。 In 014, a process of trying to connect the non-relay node extracted in 013 with the node 1 is performed. That is, the server 4 changes the non-relay node to a relay node, and waits for reception of a connection notification indicating that the node 1 has connected to the relay node for a certain period.
　０１５では、接続が成功したか否かを判定する。一定期間内に接続通知が受信できた場合にはサーバ成功と判定し（０１５のＹｅｓ）、そうでなければ失敗（０１５のＮｏ）と判定する。 At 015, it is determined whether or not the connection is successful. If the connection notification can be received within a certain period, it is determined that the server is successful (Yes in 015), and if not, it is determined that failure (No in 015).
　失敗と判定される場合、サーバ４は、テーブルＴ１，テーブルＴ２及びテーブルＴ３を参照し、電池残量が電池残量閾値未満（以下でも良い）であり、且つ通信品質が通信品質閾値以上の非中継ノードを抽出（特定）する（０１６）。 If it is determined that the server 4 fails, the server 4 refers to the tables T1, T2 and T3 and the battery remaining amount is less than the battery remaining amount threshold (or less) and the communication quality is not higher than the communication quality threshold. The relay node is extracted (specified) (016).
　サーバ４は、０１６で抽出した非中継ノードを、ノード１（切断ノード）に対する候補ノードとしてテーブルＴ４に記録する（０１７）。その後、図１０の処理が終了する。 The server 4 records the non-relay node extracted at 016 in the table T4 as a candidate node for the node 1 (disconnected node) (017). Thereafter, the process of FIG. 10 ends.
　図１１は非中継ノードとの接続試行時におけるサーバの処理例を示し、０１４の処理の詳細を示す。図１１の処理は、切断ノード毎に実行される。０２１において、サーバ４は、０１６で抽出した非中継ノードに対し、中継状態への変更指示（モードを「中継」に変更する指示）を送信する。 FIG. 11 shows a processing example of the server at the time of connection attempt with a non-relay node, and shows details of the processing of 014. The process of FIG. 11 is performed for each disconnected node. In 021, the server 4 transmits an instruction to change to the relay state (an instruction to change the mode to “relay”) to the non-relay node extracted in 016.
　０２２では、サーバ４は一定期間待機する。０２３では、サーバ４は一定期間内に切断ノードが接続されたか、すなわち、切断ノードからの接続通知が受信されたかを判定する。切断ノードが接続されたと判定される場合には処理が０２４に進み、そうでない場合には処理が０２５に進む。 At 022, the server 4 stands by for a fixed period. In 023, the server 4 determines whether the disconnection node is connected within a predetermined period, that is, whether the connection notification from the disconnection node is received. If it is determined that the disconnection node is connected, the processing proceeds to 024, and if not, the processing proceeds to 025.
　０２４では、サーバ４は、テーブルＴ３において、切断ノードの接続先のノード１のモードの内容を「中継」にする。すなわち、サーバ４は、中継状態か非中継状態を示す情報の内容を中継状態に変更する。例えば、接続通知には、接続先のノード１のＩＤが含まれており、テーブルＴ３において、当該ＩＤに対応するモードを「中継」に設定する。これによって、実際のノード１のモード（状態）と、サーバ４で管理するノード１のモード（状態）とに矛盾が生じるのを回避することができる。 At 024, the server 4 sets the content of the mode of the connection destination node 1 of the disconnection node to “relay” in the table T3. That is, the server 4 changes the content of the information indicating the relay state or the non-relay state to the relay state. For example, the connection notification includes the ID of the node 1 of the connection destination, and in the table T3, the mode corresponding to the ID is set to "relay". This makes it possible to avoid contradiction between the mode (state) of the actual node 1 and the mode (state) of the node 1 managed by the server 4.
　０２５では、０２１の処理で中継状態に変更されたノード１を非中継状態に戻すコマンドをサーバ４は送信する。その後、図１１の処理が終了する。このように、サーバ４のＣＰＵ４１（制御部）は、変更指示によって中継状態に変更されたノード１と前記切断ノードとの接続を示す接続通知が受信されない場合に、中継状態に変更されたノード１を非中継状態に変更する変更指示を送信する処理を行う。このようにして、ノード１が非中継状態に戻すことで、実際のノード１のモード（状態）と、サーバ４で管理するノード１のモード（状態）とに矛盾が生じるのを回避することができる。また、電池残量がフルでない場合には電池残量を回復させることもできる。 At 025, the server 4 transmits a command for returning the node 1 that has been changed to the relay state in the process of 021 to the non-relay state. Thereafter, the process of FIG. 11 ends. As described above, the CPU 41 (control unit) of the server 4 does not receive the connection notification indicating the connection between the node 1 changed to the relay state by the change instruction and the disconnected node, the node 1 changed to the relay state To send a change instruction to change the state to the non-relay state. In this way, by returning the node 1 to the non-relaying state, it is possible to avoid contradiction between the mode (state) of the actual node 1 and the mode (state) of the node 1 managed by the server 4 it can. In addition, when the battery level is not full, the battery level can be recovered.
　図１２は候補ノードとの接続試行時におけるサーバの処理例であり、図９の００４の処理の詳細を示す。図１２の処理は、図９にも示しているように、定期的に実施されるテーブルＴ１及びテーブルＴ２の更新（電池残量の更新）を契機に開始される。０３１において、サーバ４は、切断ノードに対応する候補ノードのリスト（テーブルＴ４）から、電池残量が電池残量閾値を超える候補ノードを選択する。 FIG. 12 shows an example of processing of the server at the time of connection attempt with a candidate node, and shows details of the processing of 004 of FIG. The process of FIG. 12 is started on the occasion of updating of the tables T1 and T2 (updating of the remaining battery amount) which is periodically performed, as also shown in FIG. In 031, the server 4 selects a candidate node whose battery remaining capacity exceeds the battery remaining capacity threshold from the list (table T4) of candidate nodes corresponding to the disconnection node.
　０３２において、サーバ４は０３１にて候補ノードが選択できたか否かを判定する。候補ノードが選択できたと判定される場合には、処理が０３３に進み、そうでない場合には図１２の処理が終了する。 At 032, the server 4 determines at 031 whether or not the candidate node could be selected. If it is determined that the candidate node has been selected, the process proceeds to 033. If not, the process of FIG. 12 ends.
　０３３では、サーバ４は、リストから選択されたノード１（選択ノードと称する）を、候補ノードのリストから削除する。０３４では、サーバ４は、選択ノードに対し、中継モードへの変更指示を送信する。 At 033, the server 4 deletes the node 1 (referred to as a selected node) selected from the list from the list of candidate nodes. At 034, the server 4 transmits an instruction to change to the relay mode to the selected node.
　０３５では、サーバ４は接続通知の受信を待つため一定期間待機する。０３６ではサーバ４は切断ノードが選択ノードに接続したか否か（接続通知が受信されたか否か）を判定する。切断ノードが選択ノードに接続したと判定される場合には、処理が０３７に進み、そうでない場合には処理が０３９に進む。 At 035, the server 4 waits for a fixed period of time to wait for reception of the connection notification. At 036, the server 4 determines whether or not the disconnection node has connected to the selected node (whether or not a connection notification has been received). If it is determined that the disconnection node is connected to the selected node, the process proceeds to 037. If not, the process proceeds to 039.
　０３７では、サーバ４は接続ノード（選択ノードに接続し、接続通知を送信したノード１）に対応する候補ノードのリスト（全ての候補ノード）を削除する。０３８では、サーバ４は選択ノードのモード“中継”をテーブルＴ３に記憶する。０３９に処理が進んだ場合には、サーバ４は選択ノードへ非中継状態への変更指示を送信する。その後、図１２の処理が終了する。 At 037, the server 4 deletes the list of candidate nodes (all candidate nodes) corresponding to the connection node (the node 1 connected to the selection node and having transmitted the connection notification). At 038, the server 4 stores the mode "relay" of the selected node in the table T3. When the process proceeds to 039, the server 4 transmits a change instruction to the non-relay state to the selected node. Thereafter, the process of FIG. 12 ends.
　次に、通信システムの具体的な動作例を示す。
　＜＜シナリオ１＞＞
　（動作１）
　図１３は、シナリオ１に係る通信システムを示す。図１３に示す例では、ＧＷ２と１０個のノード１によって無線網が形成されている。無線網は、ＧＷ２を頂点とし、番号“１”のノード１（「ノード＃１」と表記する）がＧＷ２に繋がるツリーと、番号“２”のノード１（ノード＃２）がＧＷ２に繋がるツリーとが形成されている。 Next, a specific operation example of the communication system will be shown.
<< Scenario 1 >>
(Operation 1)
FIG. 13 shows a communication system according to scenario 1. In the example shown in FIG. 13, the wireless network is formed by the GW 2 and the ten nodes 1. The wireless network has a tree in which GW2 is a vertex, and a node 1 (denoted as “node # 1”) with number “1” is connected to GW2, and a tree in which node 1 (node # 2) with number “2” is connected to GW2 And are formed.
　ここで、ノード＃１に接続されているノード＃４の子ノードであるノード＃８に注目する。ノード＃８は、親ノードであるノード＃８からの電波のＬＱＩが閾値以下となった場合、ノード＃４から切断されたと判定する（みなす）。 Here, attention is paid to node # 8 which is a child node of node # 4 connected to node # 1. When the LQI of the radio wave from the parent node, node # 8, is less than or equal to the threshold value, the node # 8 determines that the node # 4 is disconnected (considered).
　ノード＃４はノード＃８からアライブ信号が一定期間受信されないことを以て、子ノードであるノード＃８の切断を検出する。ノード＃４は、サーバ４宛てに、切断検出通知を送信する。切断検出通知は、ノード＃１及びＧＷ２を経てサーバ４に受信される。サーバ４は、切断検出通知を受けて図１０に示した処理を開始する。 The node # 4 detects the disconnection of the node # 8 which is a child node, since the alive signal is not received from the node # 8 for a certain period of time. The node # 4 transmits a disconnection detection notification to the server 4. The disconnection detection notification is received by the server 4 via the nodes # 1 and GW2. The server 4 receives the disconnection detection notification and starts the processing shown in FIG.
　（動作２）
　図１４に示すように、ノード＃４から切断されたノード＃８（切断ノード）は、再接続要求のメッセージ（信号）をノード＃８の周囲にブロードキャストで送信する。サーバ４では、ノード＃８がノード＃４以外のノード１と接続したことを示す接続通知の受信を一定期間待機する。 (Operation 2)
As shown in FIG. 14, node # 8 (disconnected node) disconnected from node # 4 broadcasts a message (signal) of a reconnection request around node # 8. The server 4 waits for reception of a connection notification indicating that the node # 8 is connected to the node 1 other than the node # 4 for a certain period of time.
　（動作３）
　図１５に示すように、再接続要求を受信したノード１のうち、中継状態のノード１であるノード＃５及びノード＃９は、接続応答のメッセージを未接続状態のノード＃８へ送信する。 (Operation 3)
As shown in FIG. 15, among the nodes 1 that have received the reconnection request, the node # 5 and the node # 9 that are the node 1 in the relay state transmit a connection response message to the node # 8 in the unconnected state.
　（動作４）
　図１６に示すように、ノード＃８は、接続応答を受信したノード１（ノード１が複数の場合、所定の優先順位に従って選択したノード１）と再接続手順を行い、再接続する。優先順位は、例えば、接続応答の受信の早い順や、通信品質が良い順などに基づいて決定される。再接続手順は、例えば、ＩＥＥＥ８０２．１５．４に規定される手順等、既存の手順で行われる。 (Operation 4)
As illustrated in FIG. 16, the node # 8 performs a reconnection procedure with the node 1 (the node 1 selected according to a predetermined priority in the case of a plurality of nodes 1) having received the connection response and reconnects. The priority is determined based on, for example, the order of early reception of connection responses, the order of good communication quality, and the like. The reconnection procedure is performed according to an existing procedure such as, for example, the procedure defined in IEEE 802.15.4.
　図１６に示す例では、ノード＃８はノード＃５と再接続手順を行いノード＃５に接続する。ノード＃８は接続通知を送信する。接続通知はノード＃５，ノード＃２，及びＧＷ２を経てサーバ４に到達する。接続通知を受信したサーバ４は、一定期間内に接続通知を受信できたので、図１０に示す処理を終了する。 In the example shown in FIG. 16, the node # 8 performs a reconnection procedure with the node # 5 and connects to the node # 5. Node # 8 sends a connection notification. The connection notification reaches the server 4 through the node # 5, the node # 2, and the GW2. The server 4 that has received the connection notification can receive the connection notification within a predetermined period, and thus ends the processing illustrated in FIG.
　＜＜シナリオ２＞＞
　（動作１）
　図１７はシナリオ２に係る通信システムを示す。図１７において、無線網のツリー構成は、図１３（シナリオ１）と同様である。但し、シナリオ２では、ノード＃５，ノード＃７，ノード＃８，ノード＃９及びノード＃１０が非中継ノード（非中継状態のノード１）となっている。 << Scenario 2 >>
(Operation 1)
FIG. 17 shows a communication system according to scenario 2. In FIG. 17, the tree configuration of the wireless network is the same as that of FIG. 13 (scenario 1). However, in scenario 2, node # 5, node # 7, node # 8, node # 9 and node # 10 are non-relay nodes (node 1 in non-relay state).
　図１７において、シナリオ１と同様に、ノード＃８がノード＃４から切断されると、ノード＃４からの切断検出通知がサーバ４で受信され、サーバ４が図１０に示した処理を開始する。 In FIG. 17, similarly to scenario 1, when node # 8 is disconnected from node # 4, a disconnection detection notification from node # 4 is received by server 4, and server 4 starts the process shown in FIG. .
　（動作２）
　図１８に示すように、ノード＃４から切断されたノード＃８（切断ノード）は、再接続要求のメッセージ（信号）をノード＃８の周囲にブロードキャストで送信する。サーバ４では、ノード＃８がノード＃４以外のノード１と接続したことを示す接続通知の受信を一定期間待機する。 (Operation 2)
As illustrated in FIG. 18, the node # 8 (disconnected node) disconnected from the node # 4 transmits a message (signal) of a reconnection request by broadcast around the node # 8. The server 4 waits for reception of a connection notification indicating that the node # 8 is connected to the node 1 other than the node # 4 for a certain period of time.
　（動作３）
　ところが、シナリオ２では、再接続要求を受信するノード＃４以外のノード１は全て非中継ノードである。非中継ノードは接続応答を送信しないため、ノード＃８は接続応答を受信できない。その結果、ノード＃８は、定期的に再接続要求をブロードキャストで送信する状態となる（図１９）。一方、サーバ４では、０１１の一定期間内に接続通知を受信できないので、０１３以降の処理を行う。 (Operation 3)
However, in scenario 2, all nodes 1 other than the node # 4 receiving the reconnection request are non-relay nodes. Node # 8 can not receive a connection response because a non-relay node does not send a connection response. As a result, node # 8 periodically transmits a reconnection request by broadcast (FIG. 19). On the other hand, since the server 4 can not receive the connection notification within the fixed period of 011, the server 4 performs the processing after 013.
　（動作４）
　図２０に示すように、サーバ４は、テーブルＴ１，テーブルＴ２及びテーブルＴ３を参照する。サーバ４は、テーブルＴ３を参照して、非中継状態のノード１を特定する。結果、ノード＃７，ノード＃５，ノード＃９，及びノード＃１０が特定される。 (Operation 4)
As shown in FIG. 20, the server 4 refers to the table T1, the table T2 and the table T3. The server 4 refers to the table T3 to identify the node 1 in the non-relay state. As a result, node # 7, node # 5, node # 9, and node # 10 are identified.
　サーバ４は、テーブルＴ１及びテーブルＴ２から、ノード＃７，ノード＃５，ノード＃９，及びノード＃１０の電池残量と、ノード＃８を対象ＩＤとする場合のＬＱＩとを抽出する。ＬＱＩの値としてノード＃８が切断される前に測定された値が用いられる。 The server 4 extracts, from the tables T1 and T2, the remaining battery capacities of the node # 7, the node # 5, the node # 9, and the node # 10, and the LQI in the case of using the node # 8 as the target ID. The value measured before node # 8 is disconnected is used as the value of LQI.
　図２０に示すように、ノード＃７について電池残量“５”及びＬＱＩ“１８”が取得され、ノード＃５について電池残量“２０”及びＬＱＩ“２５”が取得された場合を仮定する。また、ノード＃９については電池残量“２５”及びＬＱＩ“２０”が取得され、ノード＃１０については電池残量“２０”及びＬＱＩ“３”が取得されたと仮定する。 As shown in FIG. 20, it is assumed that the battery remaining amount “5” and LQI “18” are acquired for node # 7, and the battery remaining amount “20” and LQI “25” are acquired for node # 5. Further, it is assumed that the battery remaining amount “25” and the LQI “20” are acquired for the node # 9, and the battery remaining amount “20” and the LQI “3” are acquired for the node # 10.
　ここで、サーバ４が電池残量閾値“１５”と通信品質閾値“１０”とを有していると仮定する。この場合、サーバ４は電池残量及びＬＱＩのそれぞれが対応する閾値を超える非中継ノードとして、ノード＃５及びノード＃９を抽出する。 Here, it is assumed that the server 4 has the battery remaining charge threshold “15” and the communication quality threshold “10”. In this case, the server 4 extracts the node # 5 and the node # 9 as non-relay nodes in which the battery remaining amount and the LQI each exceed the corresponding threshold.
　（動作５）
　図２１に示すように、サーバ４は、動作４で抽出したノード＃５及びノード＃９に対し、中継状態への変更指示を送信して一定期間待機する（図１１の０２１、０２２）。ノード＃５及びノード＃９が中継ノードとなった結果、ノード＃８は、ノード＃５及びノード＃９から接続応答を受けることができる。そして、図２２に示すように、ノード＃８は、ノード＃５及びノード＃９から選択したノード＃５と再接続手順を行い、ノード＃５に接続する。この結果、ノード＃８からの接続通知をサーバ４が受信する。 (Operation 5)
As shown in FIG. 21, the server 4 transmits a change instruction to the relay state to the node # 5 and the node # 9 extracted in the operation 4 and stands by for a certain period (021 and 022 in FIG. 11). As a result of the nodes # 5 and # 9 becoming relay nodes, the node # 8 can receive connection responses from the nodes # 5 and # 9. Then, as shown in FIG. 22, the node # 8 performs a reconnection procedure with the node # 5 selected from the node # 5 and the node # 9, and connects to the node # 5. As a result, the server 4 receives the connection notification from the node # 8.
　（動作６）
　図２３に示すように、接続通知を受信したサーバ４、接続先のノード１（ノード＃５）以外のノード１（ノード＃９）に対し、非中継状態への変更指示を送信する。ノード＃９は、変更指示を受けて非中継状態になる。 (Operation 6)
As shown in FIG. 23, the change instruction to the non-relaying state is transmitted to the server 4 that has received the connection notification and the node 1 (node # 9) other than the connection destination node 1 (node # 5). In response to the change instruction, node # 9 enters the non-relay state.
　＜＜シナリオ３＞＞
　図２４は、シナリオ３の動作４を示す。シナリオ３の動作１，動作２，及び動作３は、シナリオ２の動作１～３（図１７～図１９）と同じであるので説明を省略する。 << Scenario 3 >>
FIG. 24 shows an operation 4 of scenario 3. The operations 1, 2, and 3 of the scenario 3 are the same as the operations 1 to 3 (FIGS. 17 to 19) of the scenario 2, and thus the description thereof is omitted.
　図２４において、サーバ４は、図１０の０１３以降の処理を行い、テーブルＴ１～Ｔ３を参照して、電池残量及びノード＃８とのＬＱＩが閾値を超える非中継ノードの抽出を行う。但し、シナリオ３では、電池残量及びノード＃８とのＬＱＩが閾値を超える非中継ノードを抽出できない。このため、サーバ４は、電池残量が閾値を超えないがＬＱＩが閾値を超える非中継ノードとして、ノード＃５，ノード＃７及びノード＃９を抽出する。サーバ４は、ノード＃８のＩＤに対応する候補ノードのリスト（テーブルＴ４）にノード＃５，ノード＃７及びノード＃９のＩＤを記録する。 In FIG. 24, the server 4 performs the processing from 013 onward in FIG. 10, and refers to the tables T1 to T3 to extract nonrelay nodes whose battery remaining amount and LQI with the node # 8 exceed the threshold. However, in scenario 3, it is not possible to extract non-relay nodes in which the remaining battery level and the LQI with node # 8 exceed the threshold. Therefore, the server 4 extracts the node # 5, the node # 7, and the node # 9 as a non-relay node in which the battery remaining amount does not exceed the threshold but the LQI exceeds the threshold. The server 4 records the IDs of the nodes # 5, # 7, and # 9 in the list (table T4) of candidate nodes corresponding to the ID of the node # 8.
　（動作５）
　図２５に示すように、サーバ４は、候補ノードを含む各ノード１から電池残量を含むデータの収集を定期的に行う。候補ノードの電池残量が電池残量閾値を超えない場合、サーバ４は特に処理を行わない。 (Operation 5)
As shown in FIG. 25, the server 4 periodically collects data including the remaining battery charge from each node 1 including the candidate node. If the battery remaining amount of the candidate node does not exceed the battery remaining amount threshold, the server 4 does not perform any particular processing.
　（動作５Ａ）
　これに対し、図２６に示すように、候補ノードの電池残量が電池残量閾値を超えた場合を仮定する。図２６の例では、候補ノードであるノード＃５及びノード＃９の電池残量が電池残量閾値を超えたとする。 (Operation 5A)
On the other hand, as shown in FIG. 26, it is assumed that the battery remaining amount of the candidate node exceeds the battery remaining amount threshold. In the example of FIG. 26, it is assumed that the battery remaining amounts of the node # 5 and the node # 9 which are candidate nodes exceed the battery remaining amount threshold.
　（動作６）
　すると、サーバ４は、ノード＃５及びノード＃９をテーブルＴ４の候補ノードのリストから消去し、ノード＃５及びノード＃９に中継状態への変更指示を送信する。ノード＃５及びノード＃９は、変更指示を受けて中継状態（中継ノード）となる。 (Operation 6)
Then, the server 4 deletes the node # 5 and the node # 9 from the list of candidate nodes in the table T4, and transmits an instruction to change to the relay state to the node # 5 and the node # 9. The node # 5 and the node # 9 enter the relay state (relay node) in response to the change instruction.
　これによって、ノード＃８は、再接続要求の送信によって、ノード＃５及びノード＃９からの接続応答を受信する。そして、図２８に示すように、ノード＃８は、ノード＃５及びノード＃９から選択したノード＃５と再接続手順を行い、ノード＃５に接続するとともに、接続通知をサーバ４へ送信する。 Thus, the node # 8 receives connection responses from the nodes # 5 and # 9 by transmitting the reconnection request. Then, as shown in FIG. 28, the node # 8 performs a reconnection procedure with the node # 5 selected from the node # 5 and the node # 9, connects to the node # 5, and transmits a connection notification to the server 4 .
　（動作７）
　接続通知を受け取ったサーバ４は、ノード＃９に非中継状態への変更指示を送信し、ノード＃９を非中継状態に遷移させる。また、ノード＃８に対応する候補ノードをテーブルＴ４から消去し、ノード＃７を候補ノードから外す。なお、ノード＃７は候補ノードとして抽出される前の非中継ノードとして扱われる。 (Operation 7)
The server 4 having received the connection notification transmits a change instruction to the non-relaying state to the node # 9, and changes the node # 9 to the non-relaying state. Further, the candidate node corresponding to the node # 8 is deleted from the table T4, and the node # 7 is removed from the candidate nodes. The node # 7 is treated as a non-relay node before being extracted as a candidate node.
　＜実施形態の作用効果＞
　実施形態では、無線網は、各ノード１が以下の構成を有するノード群（複数のノード１）を含む。
（i）環境発電素子１１と蓄電池１２とを有する。
（ii）環境発電素子１１及び蓄電池１２の少なくとも一方の電力を受けて駆動可能である。
（iii）接続要求に応じて接続要求元との接続処理を行う第１の状態（中継状態）と、前記環境発電素子１１により蓄電池１２の電池残量を回復可能であり、接続要求に応じない第２の状態（非中継状態）とで動作する。 <Operation and effect of the embodiment>
In the embodiment, the wireless network includes a node group (a plurality of nodes 1) in which each node 1 has the following configuration.
(I) The environmental power generation element 11 and the storage battery 12 are provided.
(Ii) It can be driven by receiving the power of at least one of the environmental power generation element 11 and the storage battery 12.
(Iii) The first state (relay state) in which connection processing with the connection request source is performed in response to the connection request, and the battery power of the storage battery 12 can be recovered by the environmental power generation element 11 and does not respond to the connection request It operates in the second state (non-relaying state).
　サーバ４は、無線網の制御装置として動作する。ＧＷ２は、制御装置と無線ノードとの間の通信を中継する中継装置として動作する。無線網を形成する各ノード１は、定期的に電池残量と周辺ノードとの通信品質を測定し、測定結果をＧＷ２を介してサーバ４に送信する。サーバ４は定期的に各ノード１の電池残量と周辺ノードとの通信品質を示す情報を収集してテーブルＴ１及びテーブルＴ２に記憶する。また、サーバ４は、テーブルＴ３を用いて各ノード１のモード（中継又は非中継）を管理する。 The server 4 operates as a control device of the wireless network. The GW 2 operates as a relay device that relays communication between the control device and the wireless node. Each node 1 forming the wireless network periodically measures the remaining battery level and the communication quality with the peripheral nodes, and transmits the measurement result to the server 4 via the GW 2. The server 4 periodically collects information indicating the remaining battery level of each node 1 and the communication quality with the peripheral nodes, and stores the information in the table T1 and the table T2. The server 4 also manages the mode (relay or non-relay) of each node 1 using the table T3.
　サーバ４は、無線網から切断されたノード１（切断ノード）を検出した場合には、テーブルＴ１～Ｔ３を用い、切断ノードとのＬＱＩが閾値を上回るとともに電池残量が閾値を上回る非中継状態のノード１を抽出する。抽出されるノード１は、切断ノードと接続可能な通信品質を有するとともに中継状態に変更可能な電池残量を持つ非中継状態のノード１（非中継ノード）である。サーバ４は、抽出した非中継ノードを中継状態に変更し、接続試行（すなわち、切断ノードが再接続手順によって中継状態に変更されたノード１（無線網）に接続するかどうかを試す）を行う。中継状態に変更されたノード１が切断ノードからの接続要求に応答し、再接続処理を行うことで、切断ノードは適正な（好適な電池残量及び通信品質を有する）ノード１との接続を以て、無線網に再接続されることができる。 When the server 4 detects the disconnected node 1 (disconnected node) from the wireless network, it uses tables T1 to T3 and the LQI with the disconnected node exceeds the threshold and the remaining battery capacity exceeds the threshold. Extract node 1 of The extracted node 1 is a non-relaying node 1 (non-relaying node) having communication quality connectable to the disconnection node and having the remaining battery capacity changeable to the relaying state. The server 4 changes the extracted non-relay node to the relay state, and performs a connection attempt (that is, to test whether the disconnected node is connected to the node 1 (wireless network) changed to the relay state by the reconnection procedure). . The node 1 changed to the relay state responds to the connection request from the disconnection node and performs reconnection processing, whereby the disconnection node is connected with the appropriate node 1 (having suitable battery remaining capacity and communication quality). , Can be reconnected to the wireless network.
　接続試行によって切断ノードが中継状態に変更されたノード１（無線網）に接続されない場合には、サーバ４は、中継状態に変更したノード１を非中継状態に戻す。テーブルＴ４にて管理している中継及び非中継状態との矛盾をなくすためである。 When the disconnection node is not connected to the node 1 (wireless network) changed to the relay state by the connection attempt, the server 4 returns the node 1 changed to the relay state to the non-relay state. This is to eliminate the contradiction between the relay and non-relay states managed in the table T4.
　接続試行によって切断ノードが中継状態に変更されたノード１（無線網）に接続されない場合には、サーバ４は候補ノードを抽出し、テーブルＴ４に記憶する。候補ノードは、切断ノードと接続可能な通信品質を有する（切断ノードとのＬＱＩが閾値を上回る）が中継状態に変更するには電池残量が足りない（電池残量が閾値を満たない）非中継状態のノード１である。 When the disconnection node is not connected to the node 1 (wireless network) changed to the relay state by the connection attempt, the server 4 extracts candidate nodes and stores them in the table T4. The candidate node has communication quality connectable to the disconnection node (LQI with the disconnection node exceeds the threshold) but the remaining battery capacity is not sufficient to change to the relay state (non-remaining battery capacity does not meet the threshold) non It is node 1 in the relay state.
　定期的なテーブルＴ１（電池残量）の更新時に候補ノードの電池残量が中継状態に変更可能な値（閾値を上回る値）に達した場合には、サーバ４は候補ノードのモードを中継状態に変更して接続試行を行う。実施形態によれば、切断ノードの周辺に切断ノードと接続可能な中継ノードがない場合に、適正な（好適な電池残量及び通信品質を有する）非中継ノードを中継ノードに変更して再接続を行わせることができる。すなわち、無線網を維持することが可能になる。 The server 4 relays the mode of the candidate node when the battery remaining amount of the candidate node reaches the value that can be changed to the relay state (value exceeding the threshold) at the time of periodical table T1 (battery remaining amount) update. Change to and try to connect. According to the embodiment, when there is no relay node connectable to the disconnection node in the vicinity of the disconnection node, the appropriate non-relay node (having suitable battery remaining capacity and communication quality) is changed to the relay node and reconnected Can be done. That is, it becomes possible to maintain a wireless network.
　実施形態では、サーバ４が各ノード１のモード（中継・非中継）を制御する無線網の制御装置として動作する例を説明したが、ＧＷ２が無線網の制御装置として動作しても良い。すなわち、無線網の制御装置は、各ノード１から送信されるデータを収集する収集装置（サーバ４）に実装されても良く、各ノード１から送信されるデータを上記収集装置に中継する中継装置（ＧＷ２）に実装されても良い。 In the embodiment, an example in which the server 4 operates as a control device of a wireless network controlling the mode (relay / non-relay) of each node 1 has been described, but the GW 2 may operate as a control device of the wireless network. That is, the control device of the wireless network may be implemented in a collection device (server 4) for collecting data transmitted from each node 1, and a relay device for relaying data transmitted from each node 1 to the collection device (GW2) may be implemented.
　ＧＷ２が無線網の制御装置として動作する場合、サーバ４のＣＰＵ４１が行っていた処理（図９～図１２に示す処理）は、ＧＷ２のＣＰＵ２１が行う。ＧＷ２の主記憶装置２２及び補助記憶装置２３の少なくとも一方には、テーブルＴ１～Ｔ４が記憶される。実施形態にて説明した構成は例示であり、適宜組み合わせることができる。 When the GW 2 operates as a control device of a wireless network, the CPU 21 of the GW 2 performs the processing (the processing illustrated in FIGS. 9 to 12) that the CPU 41 of the server 4 is performing. Tables T1 to T4 are stored in at least one of the main storage device 22 and the auxiliary storage device 23 of the GW2. The configurations described in the embodiments are examples and can be combined as appropriate.
１・・・無線通信ノード
２・・・ゲートウェイ
４・・・サーバ
２１，４１・・・ＣＰＵ
２２，４２・・・主記憶装置
２３，４３・・・補助記憶装置 1 ... wireless communication node 2 ... gateway 4 ... server 21, 41 ... CPU
22, 42 ... main storage 23, 43 ... auxiliary storage

Claims (6)

  1. 　各無線ノードが環境発電部と蓄電池とを有し、前記環境発電部及び前記蓄電池の少なくとも一方の電力を受けて駆動し、接続要求に応じて接続要求元との接続処理を行う第１の状態と、前記環境発電部により前記蓄電池の電池残量を回復可能であり、前記接続要求に応じない第２の状態とで動作する無線ノード群を含む無線網の制御装置において、
    　前記各無線ノードについて、前記蓄電池の電池残量を示す電池残量値と、周辺にある他の無線ノードとの通信品質を示す通信品質値と、前記第１の状態か前記第２の状態かを示す情報を記憶する記憶部と、
    　前記無線網から切断された前記無線ノード群中の無線ノードである切断ノードを検出した場合に、前記記憶部の参照によって電池残量値が電池残量閾値を上回るとともに前記切断ノードとの通信品質値が通信品質閾値を上回る前記第２の状態の無線ノードを特定する処理と、特定した前記第２の状態の無線ノードを前記切断ノードからの接続要求に応じて前記切断ノードとの接続処理を行う前記第１の状態に変更する指示を送信する処理とを実行する制御部と
    を含む無線網の制御装置。     A first state in which each wireless node includes an environmental power generation unit and a storage battery, receives and drives power of at least one of the environmental power generation unit and the storage battery, and performs connection processing with a connection request source according to a connection request. And a controller of a wireless network including a wireless node group operable in the second state in which the battery power of the storage battery can be recovered by the environmental power generation unit and which does not respond to the connection request.
    For each of the wireless nodes, a battery remaining capacity value indicating the battery remaining capacity of the storage battery, a communication quality value indicating communication quality with other wireless nodes in the vicinity, and the first state or the second state A storage unit that stores information indicating
    When a disconnected node which is a wireless node in the wireless node group disconnected from the wireless network is detected, the battery remaining amount value exceeds the battery remaining amount threshold by referring to the storage unit and the communication quality with the disconnected node is detected. A process of identifying a wireless node in the second state whose value exceeds the communication quality threshold; and a process of connecting the identified wireless node in the second state to the disconnect node in response to a connection request from the disconnect node A control unit of a wireless network, including: a control unit that executes a process of transmitting an instruction to change to the first state to be performed.
  2. 　前記指示によって前記第１の状態に変更された無線ノードと前記切断ノードとの接続を示す通知が受信されない場合に、前記指示によって前記第１の状態に変更された無線ノードを前記第２の状態に変更する指示を送信する処理を前記制御部は行う
    請求項１に記載の無線網の制御装置。     If the notification indicating the connection between the wireless node changed to the first state by the instruction and the disconnection node is not received, the wireless node changed to the first state by the instruction is changed to the second state The control device of a wireless network according to claim 1, wherein the control unit performs a process of transmitting an instruction to change to.
  3. 　前記指示によって前記第１の状態に変更された無線ノードと前記切断ノードとの接続を示す通知が受信されない場合に、前記記憶部の参照によって前記切断ノードとの通信品質値が前記通信品質閾値を上回るが電池残量値が所定量に満たない前記第２の状態の無線ノードを候補ノードとして特定し、前記候補ノードの情報を前記記憶部に記憶する処理を前記制御部は行い、前記候補ノードにおける電池残量値が前記所定量を上回る場合に前記候補ノードを前記第１の状態に変更する指示を送信する処理を前記制御部は行う
    請求項１又は２に記載の無線網の制御装置。     When the notification indicating the connection between the wireless node changed to the first state by the instruction and the disconnection node is not received, the communication quality value with the disconnection node is the communication quality threshold value by referring to the storage unit. The control unit performs a process of specifying as the candidate node the wireless node in the second state which is higher than the battery remaining value value less than the predetermined amount as a candidate node, and stores the information of the candidate node in the storage unit. 3. The control device according to claim 1, wherein the control unit performs a process of transmitting an instruction to change the candidate node to the first state when a battery remaining amount value in the exceeds the predetermined amount.
  4. 　前記指示によって前記第１の状態に変更された無線ノードと前記切断ノードとの接続を示す通知が受信された場合に、前記指示によって前記第１の状態に変更された無線ノードに関して前記記憶部に記憶されている前記第１の状態か前記第２の状態を示す情報の内容を前記第１の状態にする処理を前記制御部は行う
    請求項１から３のいずれか１項に記載の無線網の制御装置。     When the notification indicating the connection between the wireless node changed to the first state by the instruction and the disconnection node is received, the storage unit is stored in the storage unit with respect to the wireless node changed to the first state by the instruction. The wireless network according to any one of claims 1 to 3, wherein the control unit performs a process of setting the content of the information indicating the first state or the second state stored in the first state. Control device.
  5. 　各無線ノードが環境発電部と蓄電池とを有し、前記環境発電部及び前記蓄電池の少なくとも一方の電力を受けて駆動し、接続要求に応じて接続要求元との接続処理を行う第１の状態と、前記環境発電部により前記蓄電池の電池残量を回復可能であり、前記接続要求に応じない第２の状態とで動作する無線ノード群を含む無線網の前記各無線ノードについて、前記蓄電池の電池残量を示す電池残量値と、周辺にある他の無線ノードとの通信品質を示す通信品質値と、前記第１の状態か前記第２の状態かを示す情報を記憶し、
    　前記無線網から切断された前記無線ノード群中の無線ノードである切断ノードを検出した場合に、前記記憶部の参照によって電池残量値が電池残量閾値を上回るとともに前記切断ノードとの通信品質値が通信品質閾値を上回る前記第２の状態の無線ノードを特定する処理と、特定した前記第２の状態の無線ノードを前記切断ノードからの接続要求に応じて前記切断ノードとの接続処理を行う前記第１の状態に変更する指示を送信する処理とを実行する
    ことを含む無線網の制御方法。     A first state in which each wireless node includes an environmental power generation unit and a storage battery, receives and drives power of at least one of the environmental power generation unit and the storage battery, and performs connection processing with a connection request source according to a connection request. And each of the wireless nodes of a wireless network including a wireless node group operable in the second state in which the battery power of the storage battery can be recovered by the environmental power generation unit and which is not responsive to the connection request; Storing a battery remaining capacity value indicating a battery remaining capacity, a communication quality value indicating communication quality with other wireless nodes in the vicinity, and information indicating whether the first state or the second state is stored,
    When a disconnected node which is a wireless node in the wireless node group disconnected from the wireless network is detected, the battery remaining amount value exceeds the battery remaining amount threshold by referring to the storage unit and the communication quality with the disconnected node is detected. A process of identifying a wireless node in the second state whose value exceeds the communication quality threshold; and a process of connecting the identified wireless node in the second state to the disconnect node in response to a connection request from the disconnect node A control method of a wireless network, comprising: performing an operation of transmitting an instruction to change to the first state to be performed.
  6. 　各無線ノードが環境発電部と蓄電池とを有し、前記環境発電部及び前記蓄電池の少なくとも一方の電力を受けて駆動し、接続要求に応じて接続要求元との接続処理を行う第１の状態と、前記環境発電部により前記蓄電池の電池残量を回復可能であり、前記接続要求に応じない第２の状態とで動作する無線ノード群を含む無線網と、
    　前記無線網の制御装置とを備え、
    　前記制御装置は、前記各無線ノードについて、前記蓄電池の電池残量を示す電池残量値と、周辺にある他の無線ノードとの通信品質を示す通信品質値と、前記第１の状態か前記第２の状態かを示す情報を記憶する記憶部と、
    　前記無線網から切断された前記無線ノード群中の無線ノードである切断ノードを検出した場合に、前記記憶部の参照によって電池残量値が電池残量閾値を上回るとともに前記切断ノードとの通信品質値が通信品質閾値を上回る前記第２の状態の無線ノードを特定する処理と、特定した前記第２の状態の無線ノードを前記切断ノードからの接続要求に応じて前記切断ノードとの接続処理を行う前記第１の状態に変更する指示を送信する処理とを実行する制御部とを含む
    ことを特徴とする通信システム。     A first state in which each wireless node includes an environmental power generation unit and a storage battery, receives and drives power of at least one of the environmental power generation unit and the storage battery, and performs connection processing with a connection request source according to a connection request. And a wireless network including a wireless node group capable of recovering the remaining battery capacity of the storage battery by the environmental power generation unit and operating in a second state not responding to the connection request;
    And a controller for the wireless network,
    The control device determines, for each of the wireless nodes, a battery remaining amount value indicating a battery remaining amount of the storage battery, a communication quality value indicating communication quality with other wireless nodes in the vicinity, and the first state or not A storage unit that stores information indicating whether it is in the second state;
    When a disconnected node which is a wireless node in the wireless node group disconnected from the wireless network is detected, the battery remaining amount value exceeds the battery remaining amount threshold by referring to the storage unit and the communication quality with the disconnected node is detected. A process of identifying a wireless node in the second state whose value exceeds the communication quality threshold; and a process of connecting the identified wireless node in the second state to the disconnect node in response to a connection request from the disconnect node And a control unit that executes a process of transmitting an instruction to change to the first state to be performed.
PCT/JP2017/024681 2017-07-05 2017-07-05 Control device for wireless network, control method for wireless network, and communication system WO2019008707A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/JP2017/024681 WO2019008707A1 (en) 2017-07-05 2017-07-05 Control device for wireless network, control method for wireless network, and communication system
JP2019528266A JP6852792B2 (en) 2017-07-05 2017-07-05 Wireless network control device, wireless network control method, and communication system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2017/024681 WO2019008707A1 (en) 2017-07-05 2017-07-05 Control device for wireless network, control method for wireless network, and communication system

Publications (1)

Publication Number Publication Date
WO2019008707A1 true WO2019008707A1 (en) 2019-01-10

Family

ID=64950700

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2017/024681 WO2019008707A1 (en) 2017-07-05 2017-07-05 Control device for wireless network, control method for wireless network, and communication system

Country Status (2)

Country Link
JP (1) JP6852792B2 (en)
WO (1) WO2019008707A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110536347A (en) * 2019-05-16 2019-12-03 Oppo广东移动通信有限公司 A kind of power consumption control method of terminal, device and storage medium
US20220322244A1 (en) * 2020-02-20 2022-10-06 Boe Technology Group Co., Ltd. Electric power balance processing method and apparatus, system, device and storage medium
WO2023062744A1 (en) * 2021-10-13 2023-04-20 日本電信電話株式会社 Slave wireless communication device, wireless communication system, connection method in slave wireless communication device, and connection method in wireless communication system
JP7547878B2 (en) 2020-09-08 2024-09-10 沖電気工業株式会社 Wireless devices

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013168792A (en) * 2012-02-15 2013-08-29 Nippon Telegr & Teleph Corp <Ntt> Access point device and radio communication method
WO2016113884A1 (en) * 2015-01-15 2016-07-21 富士通株式会社 Control apparatus, control method, and control program

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013168792A (en) * 2012-02-15 2013-08-29 Nippon Telegr & Teleph Corp <Ntt> Access point device and radio communication method
WO2016113884A1 (en) * 2015-01-15 2016-07-21 富士通株式会社 Control apparatus, control method, and control program

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110536347A (en) * 2019-05-16 2019-12-03 Oppo广东移动通信有限公司 A kind of power consumption control method of terminal, device and storage medium
US12035245B2 (en) 2019-05-16 2024-07-09 Guangdong Oppo Mobile Telecommunications Corp., Ltd. Method for controlling power consumption of terminal, and storage medium
US20220322244A1 (en) * 2020-02-20 2022-10-06 Boe Technology Group Co., Ltd. Electric power balance processing method and apparatus, system, device and storage medium
US11758487B2 (en) * 2020-02-20 2023-09-12 Boe Technology Group Co., Ltd. Electric power balance processing method and apparatus, system, device and storage medium
JP7547878B2 (en) 2020-09-08 2024-09-10 沖電気工業株式会社 Wireless devices
WO2023062744A1 (en) * 2021-10-13 2023-04-20 日本電信電話株式会社 Slave wireless communication device, wireless communication system, connection method in slave wireless communication device, and connection method in wireless communication system

Also Published As

Publication number Publication date
JPWO2019008707A1 (en) 2020-03-26
JP6852792B2 (en) 2021-03-31

Similar Documents

Publication Publication Date Title
JP6852792B2 (en) Wireless network control device, wireless network control method, and communication system
US10952143B2 (en) Sleeping and wake-up methods and apparatuses of master-slave network, and power saving system of master-slave network
TWI484789B (en) Master device, slave device, and methods thereof
US9467942B2 (en) Wireless communication network system, wireless communication station, wireless communication device, and battery consumption smoothing method
CN107005443B (en) Method for relaying messages, residential gateway, storage device
JP2009111455A (en) Sensor network system and server computer
JP5816545B2 (en) Wireless sensor system
JP5946919B2 (en) Management system, management method and equipment
WO2016098205A1 (en) Collection system, collection device, and power control method
US9622103B2 (en) Communications network control method, computer product, and system
TW201828226A (en) Communication device, metering system and power outage notification method
US20170094579A1 (en) Sensor network system, data transmission method and sensor node used in sensor network system
US20150009859A1 (en) Wireless communication apparatus, wireless communication method, computer-readable recording medium, and wireless communication system
JP2018516031A (en) Information notification method, user terminal, first base station, and second base station
US20140372626A1 (en) Terminal, route generating method, and computer-readable recording medium
WO2010095923A2 (en) Wireless sensor network system
JP5518254B2 (en) Management server and gateway
JP2010231566A (en) Wireless sensor terminal and control method
EP3136627B1 (en) Electronic device and method
CN102486413A (en) Temperature monitoring system
CN109561482B (en) Data acquisition method, data acquisition device and intelligent terminal
JP2014064155A (en) Radio meter-reading system
US10172021B2 (en) Communication method, non-transitory computer-readable recording medium, and communication system
JP5733147B2 (en) Wireless communication method, wireless communication system, information aggregation device, and information collection device
WO2015015562A1 (en) Wireless data collection system, and wireless data collection method

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17916999

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2019528266

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 17916999

Country of ref document: EP

Kind code of ref document: A1