JP2014086886A - Relay node, child node, communication method of relay node, and communication method of child node - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that communication of a child node is disabled until a route is restructured, when a relay node is removed.SOLUTION: A relay node performing signal relay between an aggregate station forming a tree-shaped radio mesh network with a subordinate node, and a child node, includes: a determination unit for determining whether a transmission prohibition period which expires at a certain time point certain period prior to a removal time limit by which the self is to be removed; and a control unit which suspends transmission of a route structuring message to the child node when the determination unit determines that the transmission prohibition period has expired.

Description

The present invention relates to path construction of a mesh network (hereinafter referred to as a multi-hop network) when a node is removed.

In a multi-hop network having a tree structure centering on an aggregation station (hereinafter referred to as a gateway) of nodes, there are relay nodes that relay a transmission node that transmits a packet and a gateway. When this relay node is removed, a peripheral node around the relay node needs to relay the transmission node and the gateway instead of the relay node.

Patent Document 1 is a document relating to maintenance of a tree-structured multi-hop network. In Patent Document 1, in order to prevent battery-powered nodes from functioning as relay nodes from the network due to battery exhaustion, each node transmits the remaining battery level to other nodes, and the originating node transmits the remaining battery level. A node having a large number of nodes is selected as a relay node.

However, for example, when a node is used for a watt-hour meter, the watt-hour meter has an expiration date (for example, 10 years from the inspection date). In a multi-hop network having a tree structure, when a relay node is removed, a source node under the relay node does not have a route to the gateway. For this reason, the originating node needs to reconstruct the route to the gateway.

JP2007-13834A

In Patent Document 1, a node having a large remaining battery level is selected as a relay node. The child node under the selected relay node needs to construct a route to the gateway again when the relay node is removed, and communication traffic for reconstruction increases. In addition, the child node cannot communicate until the route is reconstructed after the relay node is removed. An object of the present invention is to provide a path construction that reduces communication traffic with a simple configuration when a relay node is scheduled to be removed, and to allow communication between a child node and a gateway to be continued.

The present invention is a relay node that relays signals between an aggregation station that forms a tree-like wireless multi-hop network with a subordinate node and a child node, and that is a predetermined period before the scheduled removal time when it is removed A determination unit that determines whether or not a prohibition period has passed, and a control unit that stops transmission of a route construction message to a child node when the determination unit determines that the transmission prohibition period has elapsed It is.

In addition, the present invention is a relay node that relays signals between an aggregation station that forms a tree-like wireless multi-hop network with a subordinate node and a child node, and is a predetermined period before the scheduled removal time when it is removed. A determination unit that determines whether or not a certain transmission prohibition time limit has passed, and a transmission unit that transmits the route construction message with information to be removed when the determination unit determines that the transmission prohibition time limit has passed , With.

In addition, the present invention is a relay node that relays signals between an aggregation station that forms a tree-like wireless multi-hop network with a subordinate node and a child node, and receives a removal instruction indicating that the node is to be removed When the removal instruction is received by the reception unit and the reception unit, a control unit for stopping transmission of the route construction message to the child node is provided.

Since the present invention includes a control unit that stops transmission of a route construction message to a child node when the node determines that the transmission prohibition time limit has passed, the child node has a node scheduled to be removed. A route with reduced communication traffic can be established without using a relay node, and communication between the child node and the gateway can be continued.

In addition, since the present invention includes a transmission unit that transmits the route construction message with information to be removed by itself when the node determines that the transmission prohibition period has passed, the child node is scheduled to be removed. Therefore, it is possible to construct a route that reduces communication traffic without using the relayed node as a relay node, and it is possible to continue communication between the child node and the gateway.

In addition, since the present invention includes a control unit that stops transmission of the route construction message to the child node when the node receives the removal instruction, the child node does not use the node to be removed as a relay node, A route with reduced communication traffic can be constructed, and communication between the child node and the gateway can be continued.

1 is a configuration diagram of a multihop network in Embodiment 1. FIG. FIG. 3 is a configuration diagram of a node in the first embodiment. 6 is an explanatory diagram of commands in the first embodiment. FIG. It is the management information which the node and server in Embodiment 1 have. 1 is a configuration diagram of a multihop network in Embodiment 1. FIG. 3 is a sequence diagram of a multi-hop network in the first embodiment. FIG. 3 is a flowchart of a node in the first embodiment. 3 is a flowchart of a server in the first embodiment. 3 is a flowchart of a server in the first embodiment. FIG. 6 is a configuration diagram of a multi-hop network in a second embodiment. FIG. 10 is a sequence diagram of a multi-hop network in the second embodiment. FIG. 10 is a configuration diagram of a multi-hop network in a third embodiment. FIG. 10 is a sequence diagram of a multi-hop network in the third embodiment. 10 is a flowchart of a node in the third embodiment.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of an entire multi-hop network having a tree structure including a server 100, a gateway 200, and a plurality of nodes 300 to 310 in the present embodiment.

In FIG. 1, 100 is a server. The server 100 has a function of managing and controlling a network path and state. The server 100 holds the ID and expiration date of each node in a database (not shown), and communicates with each node (described later) via the gateway 200 (described later). It is possible to transmit a scheduled removal time, which is the deadline for removing the node, and a removal instruction for removing the node.

Reference numeral 200 denotes a gateway serving as a node aggregation station device. The gateway 200 performs protocol conversion between the wide area network and the multi-hop network (including subordinate nodes). Here, the server 100 and the gateway 200 will be described as separate devices, but the gateway 200 may have the function of the server 100 in some cases. Further, the communication between the server 100 and the gateway 200 may use either wired or wireless communication, and may use an IP network such as an optical line or a mobile phone.

Reference numerals 300 to 310 denote nodes having a wireless communication function and a metering function. Nodes 300 to 309 are nodes that have already entered the multi-hop network, and node 310 is a node that is scheduled to enter the multi-hop network. As a case where a node enters, there are a case where a new node is installed, a case where a power source is turned on, a case where power is restored from a power failure, and the like. Each node has its own scheduled removal time, and the scheduled removal time may be notified from the server 100 when preset at the time of shipment. Further, the node may receive a removal instruction from the server 100.

Here, the measurement function of the node 300 will be described as a watt-hour meter that integrates and measures used power, but the present invention is not limited to this. In addition to electricity meters, there are gas meters that integrate and meter used gas, and water meters that integrate and measure the amount of water used. Further, there is a case where only a role as a relay node is achieved without having a weighing function.

When the node cannot directly communicate with the gateway 200, the node communicates with the gateway by hopping (relaying) the relay node between itself and the gateway 200. In FIG. 1, for example, when the node 309 communicates with the gateway 200, a packet transmitted by the node 309 arrives at the gateway 200 via the node 304 and the node 303 in order. Conversely, a packet transmitted by the gateway 200 arrives at the node 309 via the node 303 and the node 304 in order. Here, a case where there is one gateway and ten nodes (of which one node is scheduled to enter) will be described, but the present invention is not limited to the number shown in FIG.

FIG. 2 is a block diagram showing a functional configuration of one node shown in FIG. The node includes a transmission / reception unit 311, a control unit 312, a memory 313, and a clock 314. The gateway 200 has at least the same functional configuration. Further, the node is connected to a watt-hour meter 400 in a power consumer where the node is arranged. Here, the watt-hour meter 400 will be described as an external node, but the watt-hour meter 400 may be provided in the node.

The transmission / reception unit 311 performs data communication with the gateway 200 and other nodes wirelessly. The transmission / reception unit 311 transmits the meter reading data of the watt-hour meter 400 and its own meter reading data periodically transmitted from other nodes to the server 100, various nodes from the server 100 to the node and the watt-hour meter 400. Send and receive control requests. HELLO messages issued from the node itself, TC messages, route search requests (route requests), control messages for network maintenance and route construction such as route search responses, etc., and those messages received from gateways and other nodes Forward. In addition, when the own node has passed the transmission prohibition time limit, there is a case where the route construction message is added with information to be removed and transmitted.

The control unit 312 includes a CPU (Central Processing Unit), a ROM (Read Only Memory: not shown) that stores a control program, a RAM (Random Access Memory: not shown) used as a work area of the CPU, and the like. The CPU controls the operation of each part of the node by executing the control program. The control unit 312 includes an application control unit 315, a time management unit 316, a route control unit 317, and a removal management unit 318.

The application control unit 315 controls the process of periodically reading the meter reading data of the watt-hour meter 400, and cancels the transfer of the path construction message to the child node when the transmission prohibition period has elapsed. Control. The time management unit 316 manages the current time. When the time management unit 316 itself measures the time, it may receive a notification of the current time from another node. The removal management unit 318 performs a process of determining whether or not a transmission prohibition time limit that is a certain period before the scheduled removal time at which the removal management unit 318 is removed. The route control unit 317 manages connection information between itself and other nodes, receives route information transmitted by other nodes, and stores the route information in association with identification information of each node.

FIG. 3 shows commands used in the present embodiment. The route search request is a command for sending a message to the gateway 200 or a peripheral node in order for the calling node to search for a route to the gateway 200. The peripheral node that has received this route search request records the node from which the route search request has been received while further forwarding this message to its own peripheral node. When the peripheral node that already knows the route to the gateway 200 receives this route search request, it transmits a route search response (described later) by following the temporary route in reverse. This is repeated and a route search response is transmitted to the originating node. The source node checks the returned route search response and selects a route with the smallest number of hops or a route with good communication quality. Each route search request is given a sequence number. The node uses this sequence number so that it does not repeatedly process a route request that has already been processed. The route request has a number indicating “lifetime”, and the number of transfers is limited. Here, 01 is assigned as the communication header. Next, the route search response is a response command to the route search request. Here, 02 is assigned as a communication header. As will be described later, when a route search request is received, but when a transmission prohibition time limit that is a certain period before the scheduled removal time has elapsed, the relay node does not return a route search response.

The control request is a command for requesting specific control from the server 100 to the node. Here, 03 is assigned as a communication header. The control response is a response command from the node to the server 100 in response to the control request. Here, 04 is assigned as a communication header. When a control request is received, the relay node returns a control response even if a transmission prohibition time limit that is a certain period before the scheduled removal time has elapsed. Examples of the control request include a meter reading value request for remotely controlling the watt-hour meter, an open / close control request, and a communication confirmation request for confirming a communication path. Examples of control responses include a meter reading value response (response to the current meter indication value) that is a result of a response corresponding to the control request, an open / close control response, and a communication confirmation response that is a response that a communication confirmation has been received. There is.

The advertisement message is a command transmitted by flooding from the gateway 200 to all the nodes of the multi-hop network under the gateway. The node that has received this can detect an available peripheral node or gateway 200. Before the transmission prohibition period elapses, the node that received the advertisement message transfers this advertisement message to the neighboring nodes. However, after the transmission prohibition period elapses, the node receives the advertisement message but does not transfer it to other nodes. Here, 05 is assigned as a communication header.

The removal instruction is a removal instruction performed by the server 100 on the node. Here, 06 is assigned as a communication header. The scheduled removal time instruction is an instruction for notifying the node of the scheduled removal time, which is the time limit for the server 100 to remove. Here, 07 is assigned as a communication header. When a node receives a removal instruction, or receives an instruction for the scheduled removal time and a certain period before the deadline, it does not forward a route construction message, that is, a route search request, route search response, or advertisement message. . As a result, the child node of the relay node that has been set can prevent the network from being constructed via the relay node scheduled to be removed. The communication header has been described as 01 to 07, but a different communication header may be given for each command, and the communication header is not limited to this.

FIG. 4 shows management information managed by the node and the server 100, respectively. In FIG. 4, the removal management unit 318 manages the removal deadline. The current time indicates the current time and is managed by the time management unit 316. On the other hand, the server 100 manages a node identifier (ID) and a scheduled removal time (removal deadline) in association with each node.

FIG. 5 shows a configuration of the entire network when the entry node 310 enters the multi-hop network after the elapse of the transmission prohibition period, which is a certain period before the scheduled removal time, of the node 304 as a relay node. . In order to establish a route to the gateway 200, the joining node 310 transmits a route search request to search for the presence of a peripheral node or a gateway.

When the node 304 and the node 305 that have received the route search request return a route search response to the entry node 310, the entry node 310 knows the route candidate to the gateway 200. However, since the node 304 that has received the route search request is scheduled to be removed, the node 310 cannot communicate with the gateway 200 when the route including itself is selected and the node 304 is removed. For this reason, the node 304 does not return a route search response to the route search request to the node 310. When the node 304 does not return a route search response, the node 310 receives only the route search response from the node 305 that is not scheduled to be removed, and builds a route based on this route search response. Therefore, communication with the gateway 200 becomes possible via the node 305 that can be stably used. The case where the node 304 is scheduled to be removed refers to a case where a transmission prohibition time limit that is a certain time (for example, one hour) before the scheduled removal time has elapsed or a removal instruction has been received.

FIG. 6 is a sequence diagram of the entire system when the node 310 is installed when the node 304 is removed. Although the operation when the node 304 is instructed to be removed from the server 100 is shown here, the present invention is not limited to this. For example, when the node holds the scheduled removal time, if the difference between the current time and the scheduled removal time is less than a certain time, the transition to the scheduled removal state and the same operation as when a removal instruction is received Do.

The operation of the entire system in this embodiment will be described with reference to the sequence diagram of FIG. The server 100 transmits a removal instruction to the gateway 200 in order to issue a removal instruction to the node 304. Upon receiving the removal instruction, the gateway 200 transfers the removal instruction to the node 303. Receiving the removal instruction, the node 303 transfers the removal instruction to the node 304. The node 304 receives this removal instruction and transitions to the removal scheduled state, and thereafter does not respond or transfer the route construction message. The route construction message is a message transmitted to another node to construct a route, and specifically includes a route search request, a route search response, an advertisement message, and the like.

Next, when the entry node 310 is newly installed and participates in the multi-hop network, the entry node 310 transmits a route search request to the periphery by broadcast. Here, description will be made assuming that the node 304 and the node 305 exist around the entry node 310. The node 305 that has received the route search request returns a route search response to the joining node 310. However, the node 304 in the planned removal state does not return a route search response to the joining node 310 even if it receives a route search request.

Next, the node 310 constructs a network via the node 305 that has returned the route search response. Since there is no route construction response from the node scheduled to be removed, it is possible to construct a route via a node that is not scheduled to be removed with little traffic.

Next, in the route construction, a network is constructed with the gateway 200 and the server 100 by transmitting a route construction request to which information on the route selected by itself is added from the node 310 to the gateway 200 or the server 100. Specifically, the node 310 transmits a route construction request, and the node 305 receives it. The node 305 transfers the received route construction request to the node 303. The node 303 transfers the received route construction request to the gateway 200. The gateway 200 transmits a registration transmission of the node 310 to the server 100 based on the received route construction request, and sends a route construction response to the node 303 as a response to the route construction request. The node 303 transfers the received path construction response to the node 305. The node 305 transfers the received route construction request to the gateway 310.
The server 100 and the gateway 200 recognize that the node 310 constructs the network and the route to the node 310 and register them in the storage device.

FIG. 7 shows the operation when the node 304 is removed. In step 1, the node 304 determines whether or not a removal instruction is received from the server 100 or a change in the scheduled removal time is received.

In step 1, when the node 304 receives a removal instruction or a change of the scheduled removal time from the server 100, the removal instruction or the scheduled removal time is updated in step 2.

In step 3, the node 304 determines whether there is a removal instruction from the server 100. If there is a removal instruction in step 3, in step 4, the node 304 is in a removal scheduled state. On the other hand, if there is no removal instruction in step 3, it is determined in step 5 whether there is a scheduled removal time. Note that the scheduled removal time may be set by the server 100 in the case of the scheduled removal time previously set for the node.

If it is determined in step 5 that there is a scheduled removal time, in step 6, the node 304 determines whether the difference between the scheduled removal time and the current time is equal to or less than a predetermined time, that is, the scheduled removal time. It is determined whether or not a transmission prohibition time limit that is a certain period before the scheduled removal time has elapsed. If it is less than a certain time, it will progress to step 4 and will be in a removal plan state. On the other hand, if it is not less than the predetermined time, the process returns to step 1.

FIG. 8 shows the operation of the server 100 when a node is removed. In step 1, the server 100 compares the current time managed by its own database with the scheduled removal time for the node. If the time difference is less than a certain time (for example, less than 1 hour), that is, if the transmission prohibition time that is a certain period before the scheduled removal time has passed, the node is managed as being scheduled for removal in step 2 The removal instruction is transmitted to the corresponding node. On the other hand, if it is not less than the predetermined time, there is time until removal, and in step 3, the node is managed as a removal release state, and the release instruction setting release is transmitted to the corresponding node. In addition, when the cancellation of the removal instruction setting has already been transmitted, it is not retransmitted. Perform this operation on all nodes that manage this operation. By this operation, it is possible to automatically transmit to the nodes that are close to be removed.

When the operator removes a node other than the server management, the node is removed by a forced operation of the server. In step 4, it is determined whether there is a forced operation by the operator. If there is a forced operation in step 4, a removal instruction is transmitted to the corresponding node in step 5. Thereby, a node can be made into a removal plan state according to an operator's instruction.

FIG. 9 shows the operation of the server 100 when setting the scheduled removal time of the node. In step 1, it is determined whether or not there is a change scheduled for removal managed by the database of the server 100. If there is no change to be removed in step 1, the process ends. If there is a change, it is determined in step 2 whether there is a scheduled removal time managed in the database of the server. If there is a scheduled removal time in step 2, the scheduled removal time is transmitted to the corresponding node. If there is not, the fact that there is no scheduled removal time is transmitted to the corresponding node in step 4. This is done for all nodes that manage this work. By operating in this way, the scheduled removal time can be transmitted to the node.

With the above operation, the entry node 310 enters the multi-hop network without going through the node 304 to be removed, so that stable communication with the gateway 200 is possible even at the time of removal. It is possible to reduce the work for exchanging traffic and route information for reconstruction.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described. Here, differences from the first embodiment will be described.

FIG. 10 is a diagram illustrating a configuration of the entire network when the node 304 is scheduled to be removed. The child node 309 has already entered the network as a child node of the node 304 to be removed.

The gateway 200 transmits advertisement messages by flatting periodically or irregularly for the purpose of maintaining the route of the self-managed multi-hop network. Each node reviews the optimal route based on the advertisement message when it receives the advertisement message, and detects a gateway failure when it does not receive the advertisement message. The node that received the advertisement message checks whether or not the same advertisement message has already been received, and if it is received for the first time, the advertisement message is sent by flatting. On the other hand, if it has been received before, the packet is discarded. As each node repeats this, the advertisement message is delivered to all nodes.

Each node forwards the received advertising message of the flatting, but after the removal of the node 304 scheduled to be removed, the node 309, which is a downstream node, cannot communicate with the gateway 200, so the node 304 forwards the advertisement message. do not do. Therefore, the node 309 receives the advertisement message only from the node 302 that is not scheduled to be removed, constructs a route with the node 302, and switches the route with the gateway 200 from a route having the node 304 as a relay node to a node that relays the node 302. . As a result, the node 309 can communicate with the gateway 200 via the node 302 that can be stably used.

FIG. 11 is a sequence diagram showing the operation of the child node 309 when the node is scheduled to be removed. In this embodiment, an example of operation when the removal of the node 304 is instructed from the server 100 is shown. However, when the scheduled removal time is set in the node or when the scheduled removal time is transmitted from the server, the node When 304 compares the current time with the scheduled removal time and the difference is equal to or less than a predetermined time, the same operation as when a removal instruction is received from the server is performed.

The server 100 transmits a removal instruction to the node 304. Specifically, the server 100 transmits a removal instruction to the gateway 200. Next, the gateway 200 transmits a removal instruction to the node 303. Next, the node 303 transmits to the node 304. Upon receiving this removal instruction, the node 304 transitions to a removal scheduled state. Since the node 304 does not perform communication for constructing the route in the planned removal state, the advertisement message is not transferred.

Next, the gateway 200 transmits an advertisement message by flatting. The node 300 and the node 303 that have received the packet recognize the route to the gateway 200 by receiving the flatting packet and forward the flatting packet.

Next, the node 302 and the node 304 that have received the flooding packet recognize the route to the gateway based on the received flooding packet. The node 302 further forwards the flooding packet, but the node 304 does not forward because it is in the state of being removed. Therefore, the node 309 receives the flooding packet only from the node 302, constructs a route with the node 302 that forwarded the flooding packet, and enables communication with the gateway via the node that can be stably used.

By performing such an operation, the problem of being unable to communicate at the time of removal because a multi-hop network is constructed without going through a node scheduled to be removed, and stable communication can be provided. In addition, it is realized only with traffic instructing that it is scheduled to be removed, and traffic that excessively reconstructs traffic or traffic that exchanges route information at short intervals is not increased.

Embodiment 3 FIG.
Next, a third embodiment of the present invention will be described. Here, differences from the first embodiment will be described.

FIG. 12 shows the configuration of the entire network when the node 310 enters the network when the node 304 is scheduled to be removed. The joining node 310 needs to establish a route to the gateway 200 in order to construct a multi-hop network. Therefore, a route search request is transmitted in order to check whether there are any nodes or gateways in the vicinity.

Normally, the node or gateway that has received the route search request returns a route search response, and the node 310 enters the network based on this route search response. However, since the node 304 is scheduled to be removed, even if the network is constructed, the node 310 that is a downstream node cannot communicate with the gateway 200 after the removal. Therefore, the node 304 responds with a route search response to which removal information indicating removal is added to the response to the route search request. At this time, although the node 310 includes the nodes 304 and 305 as peripheral nodes, the node 310 can establish a route with the node 305 that is not scheduled to be removed, and can communicate with the gateway 200 via the node 305 that can be stably used.

If only the node 304 to be removed exists around the node 310, the node 310 constructs a route with the node 304 to be removed, but does not construct its own child node. In other words, the node 310 that is a child node of the node 304 to be removed is in a state where it does not transmit a route construction message. This is different from the first embodiment and the second embodiment, and is possible when the node 310 receives the route search response to which the removal information is added.

It is the operation | movement of the whole system in this Embodiment using the sequence diagram of FIG. When the scheduled removal time is transmitted from the server 100, the current time managed by itself is compared with the scheduled removal time, and if the difference is equal to or less than a certain time, the scheduled removal time is reached. In addition, although operation | movement when a node is instruct | indicated from the server 100 by the scheduled removal time is shown here, this invention is not limited to this. For example, the same operation is performed when the node holds the scheduled removal time in advance.

When the node 304 is scheduled to be removed, the node 304 transmits the route search response with removal information added thereto, and lowers the priority order of the route candidates at the node 310. When the entry node 310 enters the multi-hop network in this state, a route search request is transmitted to the surroundings by broadcast. Here, the case where the joining node 310 enters includes a case where the node is newly installed, a case where the power is turned on, a case where the power is turned off, and the like.

The node that has received the route search request returns a route search response. Therefore, the node 305 transmits a route search response. On the other hand, the node 304 scheduled to be removed transmits the route search response after adding the information indicating the removal to the route search response.

The node 310 constructs a network via the node that has received the route search response in order to construct a multi-hop network. Since the node 310 knows that the node 304 is removed from the route search response of the node 304, the node 310 constructs a network via the node 305.

If only the node 304 exists as a route candidate, the route is constructed with the node 304, but the node 310 does not connect a child node under its own, and the influence at the time of removal is reduced. Specifically, a route search response is not returned even if a route search request is sent. As a result, since it is a child node of the removed node, the route is not constructed. The influence at the time of removal can be reduced.

Further, since the node 304 manages the removal time by itself, it is possible to transmit the removal to the child node 310 immediately before the removal, and this transmission enables the child node 310 to perform an immediate path construction operation.

Further, when the time of the node 304 becomes the scheduled removal time, the node 310 that is the downstream node can immediately search for another route by transmitting the removal to its own downstream node.

FIG. 14 is a flowchart of a node regarding determination at the time of node removal. In step 1, the node determines whether or not the scheduled removal time has been received from the server 100. If the scheduled removal time is received in step 1, the scheduled removal time is updated in step 2.

When the notification of the change of the scheduled removal time is not received in Step 1 or when the scheduled removal time is updated in Step 2, the presence or absence of the scheduled removal time is determined in Step 3.

If there is a scheduled removal time in step 3, the removal scheduled time is compared with the current time of the node in step 4. On the other hand, if there is no scheduled removal time in step 3, the process ends.

If the scheduled removal time has elapsed in step 4, it becomes a scheduled removal node in step 5. As a result, route search through the child node of the grandchild node can be prevented. On the other hand, if the scheduled removal time has not elapsed, the process is terminated.

By performing such an operation, the problem of being unable to communicate at the time of removal because a multi-hop network is constructed without going through a node scheduled to be removed, and stable communication can be provided. In addition, it is realized only with traffic instructing that it is scheduled to be removed, and traffic that excessively reconstructs traffic or traffic that exchanges route information at short intervals is not increased.

100: server, 200: gateway, 300 to 310: node, 311: transceiver, 312: control unit, 313: nonvolatile memory, 314: clock, 315: application control unit, 316: time management unit, 317: path control unit 318: Removal management section, 400: Electricity meter

Claims (14)

A relay node that relays signals between an aggregation station that forms a tree-like wireless mesh network with a subordinate node and a child node,
A determination unit that determines whether or not a transmission prohibition time limit that is a certain period before the removal time limit for the removal of the self,
A control unit that cancels transmission of the path construction message to the child node when the determination unit determines that the transmission prohibition time limit has elapsed;
A relay node characterized by comprising: A relay node that relays signals between an aggregation station that forms a tree-like wireless mesh network with a subordinate node and a child node,
A determination unit that determines whether or not a transmission prohibition time limit that is a certain period before the removal time limit for the removal of the self,
A transmitting unit that adds information to be removed by the route construction message when the determination unit determines that the transmission prohibition time limit has passed;
A relay node characterized by comprising: The relay node according to claim 1, wherein the removal deadline is notified from a server that manages the removal deadline. A relay node that relays signals between an aggregation station that forms a tree-like wireless mesh network with a subordinate node and a child node,
A receiving unit for receiving a removal instruction indicating that the self is to be removed;
When receiving a removal instruction at the receiving unit, a control unit that stops transmission of the path construction message to the child node,
A relay node characterized by comprising: The relay node according to claim 1, wherein the route construction message is a response to a route search request transmitted by the child node to construct a route. The relay node according to claim 1, wherein the route construction message is an advertisement message transmitted by the aggregation station. A sub-node of a communication system including an aggregation station that forms a tree-like wireless mesh network with a subordinate node, a child node, and a relay node that performs signal relay between the aggregation station and the child node;
A receiving unit that receives a route construction message to which information that the relay node is scheduled to be removed from the relay node;
A control unit for stopping transmission of the route construction message to a grandchild node scheduled to enter the wireless mesh network when the reception unit receives the route construction message;
A child node characterized by comprising A relay node communication method that relays signals between an aggregation station and a child node that form a tree-like wireless mesh network with a subordinate node,
A determination step for determining whether or not a transmission prohibition deadline that is a certain period before the removal deadline for self removal has passed,
A control step for stopping transmission of the path construction message to the child node when it is determined in the determination step that the transmission prohibition time limit has passed;
A relay node communication method characterized by comprising: A relay node communication method that relays signals between an aggregation station and a child node that form a tree-like wireless mesh network with a subordinate node,
A determination step for determining whether or not a transmission prohibition deadline that is a certain period before the removal deadline for self removal has passed,
A transmission step of adding information to be removed by the route construction message when it is determined that the transmission prohibition period has passed in the determination step;
A relay node communication method characterized by comprising: The relay node communication method according to claim 8 or 9, wherein the removal deadline is notified from the server. A relay node communication method that relays signals between an aggregation station and a child node that form a tree-like wireless mesh network with a subordinate node,
A receiving step for receiving a removal instruction indicating that it is to be removed;
A control step of stopping transmission of a path construction message to the child node when a removal instruction is received in the reception step;
A relay node communication method characterized by comprising: 12. The relay node communication method according to claim 11, wherein the route construction message is a response to a route search request transmitted by the child node to construct a route. The relay node communication method according to claim 11, wherein the route construction message is an advertisement message transmitted by the aggregation station. A communication method of a child node of a communication system comprising: an aggregation station that forms a tree-like wireless mesh network with a subordinate node, a child node, and a relay node that performs signal relay between the aggregation station and the child node,
A receiving step of receiving a route construction message to which information that the relay node is scheduled to be removed is added from the relay node;
A control step of stopping transmission of the route construction message to the grandchild node scheduled to join the wireless mesh network when the route construction message is received in the reception step;
A child node communication method comprising:

Images