JP7237263B2 - Wireless communication terminal, wireless communication method and wireless communication program - Google Patents

Description

The present disclosure relates to a wireless communication terminal that configures a wireless mesh network.

Wireless mesh networks are used for sensor networks for collecting environmental information, networks for power meter reading collection by smart meters, and the like. In a wireless mesh network, a collection device that collects data and a wireless communication terminal that is a child device autonomously construct a network through wireless communication.

As a routing protocol for wireless mesh networks, RPL (IPv6 Routing Protocol for Low Power and Lossy Networks) described in Non-Patent Document 1 is specified as an Internet standard.
In RPL, a plurality of metrics used for route selection are defined, and setting values set as options differ for each implementation. Therefore, metric and/or setting values may differ between RPL compliant nodes. If the settings are different, even nodes conforming to RPL cannot transfer DIO (DODAG Information Object), which is a route control message from DODAG (Destination-Oriented Directed Cyclic Graph) root, which is a collection device, They cannot interoperate.

In a wireless mesh network, there is a demand to realize a faster collection cycle or a broader communication band while maintaining the data collection function of an already constructed wireless mesh network.
In Patent Document 1, in a smart meter meter reading network, an existing smart meter and a next-generation smart meter that uses a communication method that allows higher-speed communication than the communication method of the existing smart meter are integrated and enabled to communicate. is described. In Patent Document 1, by converting the signal strength value for calculating the route quality value according to the communication method and selecting the communication route suitable for each communication method, the existing smart meter and the next-generation smart meter are integrated to enable communication. Here, the communication method is a method of communication between a PHY (PHYsical) layer and a MAC (Medium Access Control) layer.

Japanese Patent No. 6752383

IETF RFC6550 "RPL: IPv6 Routing Protocol for Low Power and Lossy Networks"

In Patent Document 1, it is assumed that RPLs with the same settings are used for routing protocols, and it is not assumed that RPLs with different settings are used for routing protocols. In other words, Patent Literature 1 does not assume a case where at least one of metrics and set values are different between nodes. DIO, which is a routing control message, cannot be transferred and a route cannot be established between nodes that have different settings for at least one of the metric and setting value. Therefore, the technology described in Patent Literature 1 cannot cope with the case where the next-generation smart meter adopts an RPL with a setting different from the communication method of the existing smart meter.
An object of the present disclosure is to enable interconnection of wireless communication terminals adopting RPL with different settings of at least one of metrics and setting values.

A wireless communication terminal according to the present disclosure includes:
A wireless communication terminal that configures a wireless mesh network,
a plurality of communication units corresponding to each of a plurality of protocols;
A message based on a source protocol, which is a protocol used by a source that is another wireless communication terminal that configures the wireless mesh network, is a destination protocol among the plurality of protocols, and configures the wireless mesh network. a protocol conversion unit that converts a message based on a destination protocol used by a destination that is a wireless communication terminal different from the transmission source,
A communication unit corresponding to the destination protocol among the plurality of communication units transmits the message converted by the protocol conversion unit.

In the present disclosure, a plurality of communication units corresponding to each of a plurality of protocols are provided, a message based on the source protocol is converted into a message based on another protocol, and then transmitted by the communication unit corresponding to the other protocol. This makes it possible to interconnect wireless communication terminals adopting protocols with different settings of at least one of metrics and set values.

FIG. 2 is a configuration diagram of a communication system 51; 2 is a configuration diagram of a wireless communication terminal 10; FIG. 4 is a configuration diagram of a communication system 52; FIG. FIG. 2 is a configuration diagram of a wireless communication terminal 20; FIG. 2 is an explanatory diagram when some wireless communication terminals 10 constituting a communication system 51 are replaced with wireless communication terminals 20; FIG. 3 is an explanatory diagram when some of the wireless communication terminals 20 constituting the communication system 52 are replaced with the wireless communication terminals 10; 1 is a configuration diagram of a communication system 53 according to Embodiment 1. FIG. 1 is a configuration diagram of a wireless communication terminal 30 according to Embodiment 1. FIG. FIG. 4 is a processing flow diagram of processing for the wireless communication terminal 30 according to Embodiment 1 to enter the communication system 53; FIG. 10 is a configuration diagram of the communication system 53 before execution of the processing of the processing flow diagram shown in FIG. 9; FIG. 10 is a configuration diagram of the communication system 53 after execution of the processing of the processing flow diagram shown in FIG. 9; FIG. 10 is a processing flow diagram of processing for performing route maintenance after the wireless communication terminal 30 and the wireless communication terminal 10i according to the first embodiment enter. 4 shows an example of a first rank conversion table 341 according to Embodiment 1; FIG. 4 shows an example of a first metric conversion table 342 according to Embodiment 1; FIG. FIG. 4 is a processing flow diagram of processing for the wireless communication terminal 30 according to Embodiment 1 to enter the communication system 53; FIG. 16 is a configuration diagram of the communication system 53 before execution of the processing of the processing flow diagram shown in FIG. 15; FIG. 16 is a configuration diagram of the communication system 53 after execution of the processing of the processing flow chart shown in FIG. 15; FIG. 10 is a processing flow diagram of processing for performing route maintenance after the wireless communication terminal 10e, the wireless communication terminal 20g, and the wireless communication terminal 30f according to the first embodiment enter. FIG. 4 is a configuration diagram of a communication system 53 according to Modification 1; FIG. 11 is a configuration diagram of a wireless communication terminal 30 according to Modification 2; FIG. 13 is a diagram showing an example of a second rank conversion table 343 according to Modification 4; FIG. FIG. 11 is a diagram showing an example of a second metric conversion table 344 according to modification 4; FIG. FIG. 11 is a configuration diagram of a radio communication terminal 30 according to Modification 7;

Embodiment 1.
*** Configuration description ***
<Prerequisite configuration>
With reference to FIGS. 1 to 6, the configuration that is the premise of the first embodiment will be described.

The configuration of the communication system 51 will be described with reference to FIG.
The communication system 51 is a wireless multi-hop network composed of the collection device 1 and multiple wireless communication terminals 10 . In FIG. 1, wireless communication terminals 10a to 10m are shown as wireless communication terminals 10. FIG.

The configuration of the wireless communication terminal 10 will be described with reference to FIG.
The wireless communication terminal 10 adopts the first protocol.
Wireless communication terminal 10 includes communication device 100, sensor device 111, actuator device 112, clock calendar 113, processor 300, memory 900, auxiliary storage device 910, input interface 920, and output interface 930. Prepare.
The communication device 100 is a device for communicating with the collection device 1 and other wireless communication terminals 10 . The communication device 100 includes an antenna 101 for receiving radio signals, a PHY 102 for digitizing radio signals, and a MAC 103 for controlling in the MAC layer. The sensor device 111 is a device that performs sensing. The actuator device 112 is a device for operating external equipment. The clock calendar 113 is a device for obtaining the date and time.
The processor 300 is an IC (Integrated Circuit) that performs processing. Memory 900 is a storage device that temporarily stores data. Auxiliary storage device 910 is a storage device that stores data. The input interface 920 is an interface for inputting data from the outside. The output interface 930 is an interface for outputting data to the outside.

The wireless communication terminal 10 includes a communication unit 311 and a route identification unit 321 as functional components. Auxiliary storage device 910 stores a program that implements the function of each functional component of wireless communication terminal 10 . This program is read into memory 900 by processor 300 and executed by processor 300 . Thereby, the function of each functional component of the wireless communication terminal 10 is realized.

The configuration of the communication system 52 will be described with reference to FIG.
The communication system 52 is a wireless multi-hop network composed of the collection device 2 and multiple wireless communication terminals 20 . In FIG. 3, wireless communication terminals 20a to 20m are shown as the wireless communication terminal 20. FIG.

The configuration of the wireless communication terminal 20 will be described with reference to FIG.
The wireless communication terminal 20 employs a second protocol different from the first protocol employed by the wireless communication terminal 10 . In Embodiment 1, different protocols mean RPLs with different settings of at least one of metrics and setting values. Since a different protocol is adopted, the wireless communication terminal 20 differs from the wireless communication terminal 10 as follows.

Radio communication terminal 20 differs from radio communication terminal 10 shown in FIG. Communication device 200 includes antenna 201 , PHY 202 , and MAC 203 . Communication device 200 uses a different frequency channel than communication device 100 .

The radio communication terminal 20 differs from the radio communication terminal 10 shown in FIG. 2 in that it includes a communication section 312 and a route identification section 322 instead of the communication section 311 and the route identification section 321 as functional components. Auxiliary storage device 910 stores a program that implements the function of each functional component of wireless communication terminal 20 . This program is read into memory 900 by processor 300 and executed by processor 300 . Thereby, the function of each functional component of the wireless communication terminal 20 is realized.

As shown in FIG. 5, when some of the wireless communication terminals 10 constituting the communication system 51 are replaced with the wireless communication terminals 20, a route for multi-hop communication cannot be constructed. This is because the wireless communication terminal 10 and the wireless communication terminal 20 employ different protocols. In other words, between the wireless communication terminal 10 and the wireless communication terminal 20, the difference between the communication device 100 and the communication device 200, the difference between the communication unit 311 and the communication unit 312, the route specifying unit 321 and the route specifying unit 322 This is because there is a difference between

As shown in FIG. 6, even if some of the wireless communication terminals 20 that make up the communication system 52 are replaced with the wireless communication terminals 10, a route for multi-hop communication cannot be constructed.

<Configuration according to Embodiment 1>
A configuration according to the first embodiment will be described with reference to FIGS. 7 and 8. FIG.

A configuration of a communication system 53 according to Embodiment 1 will be described with reference to FIG.
The communication system 53 is a wireless multi-hop network composed of the collection device 1 , one or more wireless communication terminals 10 , one or more wireless communication terminals 20 , and one or more wireless communication terminals 30 .

Referring to FIG. 8, the configuration of radio communication terminal 30 according to Embodiment 1 will be described.
The radio communication terminal 30 can operate with both the first protocol adopted by the radio communication terminal 10 and the second protocol adopted by the radio communication terminal 20 . Therefore, the wireless communication terminal 30 differs from the wireless communication terminal 10 and the wireless communication terminal 20 as follows.

The radio communication terminal 30 differs from the radio communication terminal 10 shown in FIG. 2 and the radio communication terminal 20 shown in FIG. 4 in that both the communication device 100 and the communication device 200 are provided. 2, the wireless communication terminal 30 includes, as functional components, a communication unit 31 including communication units 311 and 312 and a route identification unit 32 including a route identification unit 321 and a route identification unit 322. 4 and the wireless communication terminal 20 shown in FIG. In other words, the wireless communication terminal 30 includes a communication device corresponding to each of a plurality of protocols, a communication section, and a route identification section.
Also, the radio communication terminal 30 differs from the radio communication terminal 10 shown in FIG. 2 and the radio communication terminal 20 shown in FIG. 4 in that it includes a protocol determination unit 33 and a protocol conversion unit 34 as functional components.
Auxiliary storage device 910 stores a program that implements the function of each functional component of wireless communication terminal 30 . This program is read into memory 900 by processor 300 and executed by processor 300 . Thereby, the function of each functional component of the wireless communication terminal 30 is realized.

***Description of operation***
The operation of the communication system 53 according to the first embodiment will be described with reference to FIGS. 9 to 18. FIG.
In particular, the operation procedure of the wireless communication terminal 30 in the communication system 53 according to the first embodiment corresponds to the wireless communication method according to the first embodiment. Also, a program that realizes the operation of the wireless communication terminal 30 in the communication system 53 according to the first embodiment corresponds to the wireless communication program according to the first embodiment.

<Entry processing 1>
Referring to FIG. 9, a process of entering communication system 53 by wireless communication terminal 30 according to Embodiment 1 will be described. FIG. 9 shows a process in which the wireless communication terminal 10i joins the communication system 53 shown in FIG. 10 after the wireless communication terminal 30d joins.
Here, as shown in FIG. 10, it is assumed that the wireless communication terminal 20 does not exist in the communication system 53 .

First, the operation of the radio communication terminal 30d joining the communication system 53 will be described.
(Step S101)
In the wireless communication terminal 30d, the route specifying unit 321 generates a DIS (DODAG Information Solicitation) message (DIS-1). Then, the communication unit 311 broadcasts DIS-1 from the communication device 100. FIG. Also, the route identifying unit 322 generates a DIS message (DIS-2). Then, the communication unit 312 broadcasts DIS-2 from the communication device 200. FIG. Although the wireless communication terminal 20 does not exist in the communication system 53, DIS-2 is generated because it is unknown whether the wireless communication terminal 20 exists in the wireless communication terminal 30d.
A DIS message is a request message that requests a routing message.

(Step S102)
The wireless communication terminal 10a installed near the wireless communication terminal 30d receives DIS-1 transmitted from the wireless communication terminal 30d. Then, in the wireless communication terminal 10a, the route specifying unit 321 generates a DIO (DODAG Information Object) message (DIO-1) according to DIS-1. Then, the communication unit 311 transmits DIO-1 from the communication device 100 to the wireless communication terminal 30d.
A DIO message is a routing message. The DIO message contains the path metrics in communication system 53 . Specifically, the DIO message includes a rank value, which is an evaluation index for the route from the collection device 1 to the wireless communication terminal 10a.

(Step S103)
The communication unit 311 of the wireless communication terminal 30d receives DIO-1 transmitted from the wireless communication terminal 10a. Then, in the wireless communication terminal 30d, the protocol determination unit 33 determines that DIO-1 is a message based on the first protocol, and transfers the processing to the communication unit 311 and the route identification unit 321. FIG. Specifically, the protocol determination unit 33 determines based on the difference in information included in the message. For example, the protocol determination unit 33 determines based on the difference between the parameter value specifying the metric included in the message and the flag included in the message. Note that the protocol determination unit 33 may determine whether the communication device 100 or the communication device 200 has received the message, or whether the communication unit 311 has received the message. 312 or not.

The route identifying unit 321 calculates the rank value of the route from the collection device 1 to the wireless communication terminal 30d from the rank value and metric included in DIO-1. The metric is an evaluation index of the wireless link between the wireless communication terminal 10a and the communication device 100 of the wireless communication terminal 30 when DIO-1 is received.
Here, the radio communication terminal 30d receives only DIO-1 transmitted from the radio communication terminal 10a. However, the wireless communication terminal 30d may receive DIO-1 from a plurality of nodes (one of the collection device 1, the wireless communication terminal 10, and the wireless communication terminal 30). In this case, for each DIO-1, the route identification unit 321 determines the rank of the route from the collection device 1 to the wireless communication terminal 30d based on the rank value and the metric at the time of reception included in the target DIO-1. Calculate the value and identify DIO-1 with the lowest rank value. Here, it is assumed that no DIO message has been received from the wireless communication terminal 20 .
Then, the route identifying unit 321 identifies the node that transmitted the identified DIO-1 as the node of the next hop when the collection device 1 is the destination. Here, the wireless communication terminal 10a is specified as the next-hop node. The route identification unit 321 generates a DAO (DODAG Advertisement Object) message (DAO-1). Then, the communication unit 311 transmits DAO-1 from the communication device 100 to the collection device 1 via the wireless communication terminal 10a, which is the next-hop node.
A DAO message is a connection request message to the communication system 53 . As a result, the wireless communication terminal 30d requests connection to the communication system 53, and the entry operation is completed.

Next, the operation of the wireless communication terminal 10i joining the communication system 53 will be described.
(Step S104)
In the radio communication terminal 10i, the route identifying section 321 generates a DIS message (DIS-1). Then, the communication unit 311 broadcasts DIS-1 from the communication device 100. FIG.

(Step S105)
The communication unit 311 of the wireless communication terminal 30d installed near the wireless communication terminal 10i receives DIS-1 transmitted from the wireless communication terminal 10i. In the wireless communication terminal 30d, the protocol determination unit 33 determines that DIO-1 is a message based on the first protocol, and passes the processing to the communication unit 311 and route identification unit 321. FIG. The route specifying unit 321 generates a DIO message (DIO-1) according to DIS-1. Then, the communication unit 311 transmits DIO-1 from the communication device 100 to the wireless communication terminal 10i.

(Step S106)
The communication unit 311 of the wireless communication terminal 10i receives DIO-1 transmitted from the wireless communication terminal 30d. Then, in the wireless communication terminal 10i, the route specifying unit 321 calculates the rank value of the route from the collection device 1 to the wireless communication terminal 10i from the rank value included in DIO-1 and the metric at the time of reception.
Here, the radio communication terminal 10i receives only DIO-1 transmitted from the radio communication terminal 30d. However, the wireless communication terminal 10i may receive DIO-1 from a plurality of nodes (one of the collection device 1, the wireless communication terminal 10, and the wireless communication terminal 30). In this case, for each DIO-1, the route identification unit 321 determines the rank of the route from the collection device 1 to the wireless communication terminal 10i based on the rank value and the metric at the time of reception included in the target DIO-1. Calculate the value and identify DIO-1 with the lowest rank value.
Then, the route identifying unit 321 identifies the node that transmitted the identified DIO-1 as the node of the next hop when the collection device 1 is the destination. Here, the wireless communication terminal 30d is identified as the next-hop node. The route identification unit 321 generates a DAO message (DAO-1). Then, the communication unit 311 transmits DAO-1 from the communication device 100 to the collection device 1 via the wireless communication terminal 30d, which is the next-hop node.
As a result, the wireless communication terminal 10i requests connection to the communication system 53, and the joining operation is completed. As a result, the communication system 53 shown in FIG. 11 is constructed.

As described above, when the wireless communication terminal 30d participates in the communication system 53, the wireless communication terminal 30d uses the communication device 100 and the communication unit 311 to transmit the DIS-1 generated by the route identification unit 321, and DIS-2 generated by the route identifying unit 321 is transmitted using the unit 312 . This searches for a connectable wireless communication terminal. Then, the wireless communication terminal 30 d identifies that the received DIO message corresponds to the first protocol by the protocol determination section 33 , and forwards the processing to the communication section 311 and the route identification section 321 . As a result, the wireless communication terminal 30d can enter the communication system 53 by the same operation as the wireless communication terminal 10 does.

<Maintenance processing 1>
With reference to FIG. 12, a process of performing route maintenance after the radio communication terminal 30d and the radio communication terminal 10i according to Embodiment 1 enter the network will be described. FIG. 12 shows a process of performing route maintenance by the wireless communication terminal 10a, the wireless communication terminal 30d, and the wireless communication terminal 10i in the communication system 53 shown in FIG.
Here, as shown in FIG. 11, it is assumed that the wireless communication terminal 20 does not exist in the communication system 53 .

First, the operation of route maintenance performed by the wireless communication terminal 10a will be described.
(Step S201)
In the wireless communication terminal 10a, when the Trickle timer specified in RFC6206 expires, the route specifying unit 321 sets each DIO-1 received up to that point as the target DIO-1. The route identifying unit 321 calculates the rank value of the route from the collection device 1 to the wireless communication terminal 10a from the rank value included in the target DIO-1 and the metric at the time of reception.
Then, the route identifying unit 321 identifies DIO-1 with the lowest rank value. The route specifying unit 321 determines the node (one of the collection device 1, the wireless communication terminal 10, and the wireless communication terminal 30) that transmitted the specified DIO-1 as the next hop node when the collection device 1 is the transmission destination. Identify as Here, the collection device 1 is identified as the next-hop node. The route identification unit 321 generates a DAO message (DAO-1). Then, the communication unit 311 transmits DAO-1 from the communication device 100 to the collection device 1, which is the next-hop node.

(Step S202)
In the wireless communication terminal 10a, the route identifying section 321 generates a DIO message (DIO-1). Then, the communication unit 311 broadcasts DIO-1 from the communication device 100. FIG.

Next, the operation of route maintenance performed by the wireless communication terminal 30d will be described.
(Step S203)
Similarly, in the wireless communication terminal 30d, when the Trickle timer expires, the route specifying unit 321 sets each DIO-1 received so far as the target DIO-1. The route specifying unit 321 calculates the rank value of the route from the collection device 1 to the wireless communication terminal 30d from the rank value included in the target DIO-1 and the metric at the time of reception.
Then, the route identification unit 321 determines the node (one of the collection device 1, the wireless communication terminal 10, and the wireless communication terminal 30) that transmitted the identified DIO-1 as the next hop when the collection device 1 is the transmission destination. node. Here, the wireless communication terminal 10a is specified as the next-hop node. The route identification unit 321 generates a DAO message (DAO-1). Then, the communication unit 311 transmits DAO-1 from the communication device 100 to the collection device 1 via the wireless communication terminal 10a, which is the next-hop node.

(Step S204)
In the wireless communication terminal 30d, the route identifying section 321 generates a DIO message (DIO-1). Then, the communication unit 311 broadcasts DIO-1 from the communication device 100. FIG.

(Step S205)
In the wireless communication terminal 30d, the protocol converter 34 converts DIO-1 based on the first protocol generated in step S204 into DIO-2 based on the second protocol. Then, the communication unit 312 broadcasts DIO-2 from the communication device 200. FIG.
Specifically, the protocol converter 34 converts the evaluation index based on the first protocol included in DIO-1 into the evaluation index based on the second protocol, thereby converting DIO-1 into DIO-2. In other words, the protocol converter 34 converts DIO-1 to DIO-2 by converting the rank value based on the first protocol into the rank value based on the second protocol. That is, the protocol converter 34 converts the scale of the rank value in the first protocol to the scale of the rank value in the second protocol.

For example, the protocol converter 34 refers to either the first rank conversion table 341 shown in FIG. 13 or the first metric conversion table 342 shown in FIG. 14 to convert the rank value and metric. In FIG. 13, for the first protocol, using LQL (Link Quality Level) that evaluates the wireless link based on the received signal strength (RSSI), if the signal strength is -90 dBm (decibel milliwatt) or more, 128, -120 dBm A rank value such as 512 if less than -90 dBm and 4096 if less than -120 dBm is set. On the other hand, for the second protocol, a rank value (continuous value) based on the packet arrival rate according to ETX (Expected Transmission Count) defined in RFC6551 is used. Since ETX is not measured in the first protocol, it needs to be converted to a rank value in the second protocol. Therefore, the protocol converter 34 derives the rank value of ETX from the RSSI measured by the first protocol based on the table of FIG.
Instead of using the conversion table as shown in FIG. 13, the protocol conversion unit 34 may use a conversion formula for LQL rank values and EXT rank values as shown in FIG.

Next, the operation of route maintenance performed by the wireless communication terminal 10i will be described.
(Step S206)
Similarly, in the wireless communication terminal 10i, when the Trickle timer expires, the route specifying unit 321 sets each DIO-1 received so far as the target DIO-1. The route identifying unit 321 calculates the rank value of the route from the collection device 1 to the wireless communication terminal 10i from the rank value included in the target DIO-1 and the metric at the time of reception.
Then, the route identification unit 321 determines the node (one of the collection device 1, the wireless communication terminal 10, and the wireless communication terminal 30) that transmitted the identified DIO-1 as the next hop when the collection device 1 is the transmission destination. node. Here, the wireless communication terminal 30d is identified as the next-hop node. The route identification unit 321 generates a DAO message (DAO-1). Then, the communication unit 311 transmits DAO-1 from the communication device 100 to the collection device 1 via the wireless communication terminal 30d, which is the next-hop node.

(Step S207)
In the radio communication terminal 10i, the route identifying section 321 generates a DIO message (DIO-1). Then, the communication unit 311 broadcasts DIO-1 from the communication device 100. FIG.

As described above, the wireless communication terminal 30d transmits DIO-1 based on the first protocol and DIO-2 based on the second protocol converted from DIO-1 when performing route maintenance. That is, the wireless communication terminal 30d transmits DIO-1 based on the transmission source protocol (first protocol) used by the wireless communication terminal 10a of the next hop, and a protocol other than the first protocol (second protocol). Send DIO-2 based on Thereby, the radio communication terminal 30d maintains the communication system 53 in which it participates.

<Entry processing 2>
Referring to FIG. 15, the process of entering communication system 53 by wireless communication terminal 30 according to Embodiment 1 will be described. FIG. 15 shows processing in which the wireless communication terminal 10e, the wireless communication terminal 20g, and the wireless communication terminal 30f enter the communication system 53 shown in FIG. 16 in this order.
Here, unlike the entry process 1, the wireless communication terminal 20 exists in the communication system 53 on the way.

First, the operation of the wireless communication terminal 10e entering the communication system 53 will be described.
(Step S301)
In the radio communication terminal 10e, the route identifying section 321 generates a DIS message (DIS-1). Then, the communication unit 311 broadcasts DIS-1 from the communication device 100. FIG.

(Step S302)
The communication unit 311 of the wireless communication terminal 30b installed near the wireless communication terminal 10e receives DIS-1 transmitted from the wireless communication terminal 10e. In the wireless communication terminal 30b, the protocol determination unit 33 determines that DIO-1 is a message based on the first protocol, and passes the processing to the communication unit 311 and route identification unit 321. FIG. The route specifying unit 321 generates a DIO message (DIO-1) according to DIS-1. Then, the communication unit 311 transmits DIO-1 from the communication device 100 to the wireless communication terminal 10i.

(Step S303)
The communication unit 311 of the wireless communication terminal 10e receives DIO-1 transmitted from the wireless communication terminal 30b. Then, in the wireless communication terminal 10e, the route specifying unit 321 calculates the rank value of the route from the collection device 1 to the wireless communication terminal 10e from the rank value included in DIO-1 and the metric at the time of reception.
Here, the radio communication terminal 10e receives only DIO-1 transmitted from the radio communication terminal 30b. However, the wireless communication terminal 10e may receive DIO-1 from a plurality of nodes (one of the collection device 1, the wireless communication terminal 10, and the wireless communication terminal 30). In this case, for each DIO-1, the route identification unit 321 determines the rank of the route from the collection device 1 to the wireless communication terminal 10e based on the rank value and the metric at the time of reception included in the target DIO-1. Calculate the value and identify DIO-1 with the lowest rank value.
Then, the route identifying unit 321 identifies the node that transmitted the identified DIO-1 as the node of the next hop when the collection device 1 is the destination. Here, the wireless communication terminal 30b is identified as the next-hop node. The route identification unit 321 generates a DAO message (DAO-1). Then, the communication unit 311 transmits DAO-1 from the communication device 100 to the collection device 1 via the wireless communication terminal 30b, which is the next-hop node.
As a result, the wireless communication terminal 10e requests connection to the communication system 53, and the joining operation is completed.

Next, the operation of the radio communication terminal 20g joining the communication system 53 will be described.
(Step S304)
In the wireless communication terminal 20g, the route identifying section 322 generates a DIS message (DIS-2). Then, the communication unit 312 broadcasts DIS-2 from the communication device 200. FIG.

(Step S305)
The communication unit 312 of the wireless communication terminal 30b installed near the wireless communication terminal 20g receives DIS-2 transmitted from the wireless communication terminal 20g. In the wireless communication terminal 30b, the protocol determination unit 33 determines that DIO-2 is a message based on the second protocol, and transfers the processing to the communication unit 312 and the route identification unit 322. FIG.
The route identification unit 322 generates a DIO message (DIO-2) according to DIS-2. At this time, the protocol conversion unit 34 converts the rank values from the collection device 1 to the wireless communication terminal 30b into rank values based on the second protocol. The route identifying unit 322 generates DIO-2 including the rank value converted by the protocol converting unit 34. FIG. Then, the communication unit 312 transmits DIO-2 from the communication device 200 to the wireless communication terminal 20g.

(Step S306)
The communication unit 312 of the wireless communication terminal 20g receives DIO-2 transmitted from the wireless communication terminal 30b. Then, in the wireless communication terminal 20g, the route specifying unit 322 calculates the rank value of the route from the collection device 1 to the wireless communication terminal 20g from the rank value included in DIO-2 and the metric at the time of reception.
Here, the radio communication terminal 20g receives only DIO-2 transmitted from the radio communication terminal 30b. However, the wireless communication terminal 20g may receive DIO-2 from a plurality of nodes (either the wireless communication terminal 20 or the wireless communication terminal 30). In this case, for each DIO-2, the route identification unit 322 determines the rank of the route from the collection device 1 to the wireless communication terminal 20g based on the rank value included in the target DIO-2 and the metric at the time of reception. Calculate the value and identify DIO-2 with the lowest rank value.
Then, the route identifying unit 322 identifies the node that transmitted the identified DIO-2 as the next hop node when the collection device 1 is the destination. Here, the wireless communication terminal 30b is identified as the next-hop node. The route identification unit 322 generates a DAO message (DAO-2).

Then, the communication unit 312 transmits DAO-2 from the communication device 200 to the collection device 1 via the wireless communication terminal 30b, which is the next-hop node. As a result, the wireless communication terminal 20g requests connection to the communication system 53, and the entry operation is completed.
At this time, in the wireless communication terminal 30b, when the communication unit 312 receives the DAO-2 transmitted by the wireless communication terminal 20g, the protocol determination unit 33 determines that the DAO-2 is a message based on the second protocol. do. Then, the protocol converter 34 converts DAO-2 based on the second protocol into DAO-1 based on the first protocol used by the collection device 1, which is the next hop of the wireless communication terminal 30b. The communication unit 311 then transmits DAO-1 from the communication device 100 to the collection device 1 .

Next, the operation of the radio communication terminal 30f joining the communication system 53 will be described.
(Step S307)
In the wireless communication terminal 30f, the route identifying section 321 generates a DIS message (DIS-1). Then, the communication unit 311 broadcasts DIS-1 from the communication device 100. FIG. Also, the route identifying unit 322 generates a DIS message (DIS-2). Then, the communication unit 312 broadcasts DIS-2 from the communication device 200. FIG.

(Step S308)
The wireless communication terminal 30b and the wireless communication terminal 10e installed near the wireless communication terminal 30f receive the DIS-1 transmitted from the wireless communication terminal 30f. Then, in the wireless communication terminal 30b, the route specifying unit 321 generates a DIO message (DIO-1) according to DIS-1. Then, the communication unit 311 transmits DIO-1 from the communication device 100 to the wireless communication terminal 30f. Similarly, in the radio communication terminal 10e, the route identifying section 321 generates a DIO message (DIO-1) according to DIS-1. Then, the communication unit 311 transmits DIO-1 from the communication device 100 to the wireless communication terminal 30f.
Here, DIO-1 contains the rank value based on the first protocol.

(Step S309)
The wireless communication terminal 30b and the wireless communication terminal 20g installed near the wireless communication terminal 30f receive the DIS-2 transmitted from the wireless communication terminal 30f. Then, in the wireless communication terminal 30b, the route specifying unit 322 generates a DIO message (DIO-2) according to DIS-2. Then, the communication unit 312 transmits DIO-2 from the communication device 200 to the wireless communication terminal 30f. Similarly, in the radio communication terminal 20g, the route specifying unit 322 generates a DIO message (DIO-2) according to DIS-2. Then, the communication unit 312 transmits DIO-2 from the communication device 200 to the wireless communication terminal 30f.
Here, DIO-2 contains the rank value based on the second protocol.

(Step S310)
The communication unit 311 of the wireless communication terminal 30f receives DIO-1 transmitted from the wireless communication terminal 30b and DIO-1 transmitted from the wireless communication terminal 10e. Then, in the wireless communication terminal 30f, the protocol determination unit 33 determines that the two DIO-1 are messages based on the first protocol, and transfers the processing to the communication unit 311 and the route identification unit 321. FIG. The route identifying unit 321 calculates the rank value of the route from the collecting device 1 to the wireless communication terminal 30f for each of the two DIO-1s from the rank value included in the target DIO-1 and the metric at the time of reception. do.

The communication unit 312 of the wireless communication terminal 30f receives DIO-2 transmitted from the wireless communication terminal 30b and DIO-2 transmitted from the wireless communication terminal 20g. Then, in the wireless communication terminal 30f, the protocol determination unit 33 determines that the two DIO-2 are messages based on the second protocol, and transfers the processing to the communication unit 312 and the route identification unit 322. FIG. For each of the two DIO-2s, the route identification unit 322 calculates the rank value of the route from the collection device 1 to the wireless communication terminal 30f from the rank value included in the target DIO-2 and the metric at the time of reception. do.

The protocol converter 34 of the wireless communication terminal 30f converts the calculated rank value into a rank value in the standard format. This allows the rank value based on the first protocol to be compared with the rank value based on the second protocol.
Here, the protocol converter 34 refers to the first rank conversion table 341 and converts the rank value based on the second protocol calculated from DIO-2 into the rank value based on the first protocol. Then, the route identification unit 321 compares the four rank values of the two rank values calculated from the two DIO-1 and the two converted rank values calculated from the two DIO-2, Identify DIO-1 or DIO-2 with the lowest rank value. The route identifying unit 321 identifies the node that transmitted the identified DIO-1 or DIO-2 as the next hop node when the collection device 1 is the destination. Here, DIO-1 transmitted from the wireless communication terminal 30b is identified, and the communication device 100 of the wireless communication terminal 30b is identified as the next-hop node.
The route identification unit 321 generates a DAO message (DAO-1). Then, the communication unit 311 transmits DAO-1 from the communication device 100 to the collection device 1 via the communication device 100 of the wireless communication terminal 30b, which is the next-hop node. At this time, when DAO-1 is received in the wireless communication terminal 30b, the protocol determination unit 33 determines that the message is based on the first protocol, and the communication unit 311 transmits the message to the collection device 1. FIG.
As a result, the wireless communication terminal 30f issues a connection request to the communication system 53, and the joining operation is completed. As a result, a communication system 53 shown in FIG. 17 is constructed.

Here, rank values based on the second protocol were converted to rank values based on the first protocol. However, a rank value based on the first protocol may be converted to a rank value based on the second protocol. Also, the rank value based on the first protocol and the rank value based on the second protocol may be converted into a common format.
Here, the rank value is converted after the rank value of the route from the collection device 1 to the wireless communication terminal 30f is calculated. However, after converting the rank value included in at least one of DIO-1 and DIO-2, the rank value of the route from the collection device 1 to the wireless communication terminal 30f may be calculated.

As described above, the wireless communication terminal 20g can enter the communication system 53 via the wireless communication terminal 30b.
Also, the wireless communication terminal 30f converts at least one of the rank value based on the first protocol and the rank value based on the second protocol to enable comparison. This makes it possible to identify the next-hop node even when DIO messages based on multiple protocols are received.

<Maintenance processing 2>
Referring to FIG. 18, a process of performing route maintenance after the wireless communication terminal 10e, the wireless communication terminal 20g, and the wireless communication terminal 30f enter the network according to the first embodiment will be described. FIG. 18 shows a process of performing route maintenance by the wireless communication terminal 30b, the wireless communication terminal 10e, the wireless communication terminal 20g, and the wireless communication terminal 30f in the communication system 53 shown in FIG.

First, the operation of route maintenance performed by the wireless communication terminal 30b will be described.
(Step S401)
In the wireless communication terminal 30b, when the Trickle timer expires, the route specifying unit 321 sets each DIO-1 received so far as the target DIO-1. The route specifying unit 321 calculates the rank value of the route from the collection device 1 to the wireless communication terminal 30b from the rank value included in the target DIO-1 and the metric at the time of reception. Further, the route identifying unit 322 sets each DIO-2 received so far as the target DIO-2. The route specifying unit 322 calculates the rank value of the route from the collection device 1 to the wireless communication terminal 30b from the rank value included in the target DIO-2 and the metric at the time of reception.
The protocol converter 34 converts the calculated rank value into a rank value in the standard format. The conversion method is the same as the processing in step S310 of FIG. The route identifying unit 321 identifies DIO-1 or DIO-2 that has the lowest rank value. The route identifying unit 321 transmits the node (one of the collection device 1, the wireless communication terminal 10, the wireless communication terminal 20, and the wireless communication terminal 30) that transmitted the specified DIO-1 or DIO-2 to the collection device 1. Identifies the node as the next hop in the case of earlier. Here, the collection device 1 is identified as the next-hop node. The route identification unit 321 generates a DAO message (DAO-1). Then, the communication unit 311 transmits DAO-1 from the communication device 100 to the collection device 1, which is the next-hop node.

(Step S402)
In the radio communication terminal 30b, the route identifying section 321 generates a DIO message (DIO-1). Then, the communication unit 311 broadcasts DIO-1 from the communication device 100. FIG.

(Step S403)
In the wireless communication terminal 30b, the protocol converter 34 converts DIO-1 based on the first protocol generated in step S402 into DIO-2 based on the second protocol. Then, the communication unit 312 broadcasts DIO-2 from the communication device 200. FIG. A specific conversion method is the same as the conversion method in the process of step S205 in FIG.

Next, the operation of route maintenance performed by the wireless communication terminal 10e will be described.
(Step S404)
Similarly, in the wireless communication terminal 10e, when the Trickle timer expires, the route specifying unit 321 sets each DIO-1 received so far as the target DIO-1. The route identifying unit 321 calculates the rank value of the route from the collection device 1 to the wireless communication terminal 10e from the rank value included in the target DIO-1 and the metric at the time of reception.
Then, the route identification unit 321 determines the node (one of the collection device 1, the wireless communication terminal 10, and the wireless communication terminal 30) that transmitted the identified DIO-1 as the next hop when the collection device 1 is the transmission destination. node. Here, the wireless communication terminal 30b is identified as the next-hop node. The route identification unit 321 generates a DAO message (DAO-1). Then, the communication unit 311 transmits DAO-1 from the communication device 100 to the collection device 1 via the wireless communication terminal 30b, which is the next-hop node.

(Step S405)
In the radio communication terminal 10e, the route identifying section 321 generates a DIO message (DIO-1). Then, the communication unit 311 broadcasts DIO-1 from the communication device 100. FIG.

Next, the operation of route maintenance by the wireless communication terminal 20g will be described.
(Step S406)
Similarly, in the wireless communication terminal 20g, when the Trickle timer expires, the route specifying unit 322 sets each DIO-2 received so far as the target DIO-2. The route specifying unit 322 calculates the rank value of the route from the collection device 1 to the wireless communication terminal 20g from the rank value included in the target DIO-2 and the metric at the time of reception.
Then, the route identifying unit 322 identifies the node that transmitted the identified DIO-2 (either the wireless communication terminal 20 or the wireless communication terminal 30) as the next hop node when the collection device 1 is the destination. do. Here, the wireless communication terminal 30b is identified as the next-hop node. The route identification unit 321 generates a DAO message (DAO-2). Then, the communication unit 311 transmits DAO-2 from the communication device 200 to the collection device 1 via the wireless communication terminal 30b, which is the next-hop node.
At this time, in the wireless communication terminal 30b, when the communication unit 312 receives the DAO-2 transmitted by the wireless communication terminal 20g, the protocol determination unit 33 determines that the DAO-2 is a message based on the second protocol. do. Then, the protocol converter 34 converts DAO-2 based on the second protocol into DAO-1 based on the first protocol used by the collection device 1, which is the next hop of the wireless communication terminal 30b. The communication unit 311 then transmits DAO-1 from the communication device 100 to the collection device 1 .

(Step S407)
In the wireless communication terminal 20g, the route identifying section 322 generates a DIO message (DIO-2). Then, the communication unit 312 broadcasts DIO-2 from the communication device 200. FIG.

Next, the operation of route maintenance by the wireless communication terminal 30f will be described.
(Step S408)
In the radio communication terminal 30f, when the Trickle timer expires, the route specifying unit 321 sets each DIO-1 received so far as the target DIO-1. The route identifying unit 321 calculates the rank value of the route from the collection device 1 to the wireless communication terminal 30f from the rank value included in the target DIO-1 and the metric at the time of reception. Further, the route identifying unit 322 sets each DIO-2 received so far as the target DIO-2. The route specifying unit 322 calculates the rank value of the route from the collection device 1 to the wireless communication terminal 30f from the rank value included in the target DIO-2 and the metric at the time of reception.
The protocol converter 34 converts the calculated rank value into a rank value in the standard format. The conversion method is the same as the processing in step S310 of FIG. The route identifying unit 321 identifies DIO-1 or DIO-2 that has the lowest rank value. The route identifying unit 321 transmits the node (one of the collection device 1, the wireless communication terminal 10, the wireless communication terminal 20, and the wireless communication terminal 30) that transmitted the specified DIO-1 or DIO-2 to the collection device 1. Identifies the node as the next hop in the case of earlier. Here, the communication device 100 of the wireless communication terminal 30b is identified as the next-hop node. The route identification unit 321 generates a DAO message (DAO-1). Then, the communication unit 311 transmits DAO-1 from the communication device 100 to the collection device 1 via the communication device 100 of the wireless communication terminal 30b, which is the next-hop node.

(Step S409)
In the radio communication terminal 30f, the route identifying section 321 generates a DIO message (DIO-1). Then, the communication unit 311 broadcasts DIO-1 from the communication device 100. FIG.

(Step S410)
In the wireless communication terminal 30f, the protocol converter 34 converts DIO-1 based on the first protocol generated in step S409 into DIO-2 based on the second protocol. Then, the communication unit 312 broadcasts DIO-2 from the communication device 200. FIG. A specific conversion method is the same as the conversion method in the process of step S205 in FIG.

As described above, the wireless communication terminal 30b and the wireless communication terminal 30f transmit DIO-1 based on the first protocol and transmit the second protocol DIO-2 converted from DIO-1 when performing route maintenance. do. That is, the wireless communication terminal 30b and the wireless communication terminal 30f transmit DIO-1 based on the transmission source protocol (first protocol) used by the wireless communication terminal 10a of the next hop, and other protocols other than the first protocol. (Second protocol) based DIO-2 is sent. As a result, the wireless communication terminal 30b and the wireless communication terminal 30f maintain the communication system 53 they have entered.

*** Effect of Embodiment 1 ***
As described above, the wireless communication terminal 30 according to Embodiment 1 includes a plurality of communication units corresponding to a plurality of protocols, converts a message based on the source protocol into a message based on another protocol, and It is transmitted by a communication unit that supports other protocols. This makes it possible to interconnect wireless communication terminals adopting protocols with different settings of at least one of metrics and set values.

Further, the wireless communication terminal 30 according to Embodiment 1 converts the rank values calculated from the routing control messages based on each of a plurality of protocols into a reference format and compares them, thereby specifying the minimum rank value. . This makes it possible to identify the next-hop node even when DIO messages based on multiple protocols are received.

***Other Configurations***
<Modification 1>
In Embodiment 1, the communication system 53 configured by the collection device 1, the wireless communication terminal 10, the wireless communication terminal 20, and the wireless communication terminal 30 has been described. However, as shown in FIG. 19, the communication system 53 may be configured by a collection device 2 instead of the collection device 1. FIG.
Even in this case, as in the first embodiment, the wireless communication terminal 30 converts the DIO message and the DAO message to use the second protocol different from the first protocol used by the collection device 2. It is possible to allow the wireless communication terminal 10 to participate in the communication system 53 .

<Modification 2>
In Embodiment 1, wireless communication terminal 30 includes both communication device 100 and communication device 200 . Communication device 100 and communication device 200 may use the same frequency channel. In this case, as shown in FIG. 20, radio communication terminal 30 is configured to include communication device 500 that uses the same frequency channel as communication device 100 and communication device 200 instead of communication device 100 and communication device 200. It's okay. This makes it possible to reduce the number of communication devices included in the wireless communication terminal 30 .
In this case, it is not possible to determine which protocol the message is based on, depending on which of communication device 100 and communication device 200 received the message. However, as explained in the first embodiment, it is possible to determine which protocol is based on the content of the message.

<Modification 3>
In Embodiment 1, in steps S204 and S205 of FIG. 12, steps S402 and S403 of FIG. 18, and steps S409 and S410 of FIG. was broadcast.
However, if it is clear that one protocol is not being used, the wireless communication terminal 30 should broadcast only the DIO message based on the protocol being used. For example, when it is clear that there is no wireless communication terminal 10 using the first protocol, the wireless communication terminal 30 may broadcast only DIO-2.

<Modification 4>
In Embodiment 1, the protocol converter 34 refers to the first rank conversion table 341 and the first metric conversion table 342 to convert DIO-1 to DIO-2. When converting DIO-2 to DIO-1, the protocol converter 34 may refer to either the second rank conversion table 343 shown in FIG. 21 or the second metric conversion table 344 shown in FIG. . This allows conversion of DIO-2 to DIO-1 in the same manner as conversion of DIO-1 to DIO-2.

<Modification 5>
In Embodiment 1, wireless communication terminal 10 using the first protocol and wireless communication terminal 20 using the second protocol are interconnected using wireless communication terminal 30 . However, even if there are wireless communication terminals that use three or more protocols, they can be interconnected using the wireless communication terminal 30 based on the same concept.
In other words, the wireless communication terminal 30 includes the communication unit 31, the route specifying unit 32, and the communication device corresponding to each protocol, and converts the message into each protocol. can be interconnected even if

When three or more protocols are used, each protocol can be configured by defining intermediate rank values for conversion and preparing a conversion table between the rank values in each protocol and the intermediate rank values. The rank value used can be transformed.
That is, when converting the rank value in the first protocol into the rank value in the second protocol, the protocol conversion unit 34 converts the rank value in the first protocol into an intermediate rank value, and converts the intermediate rank value into the second protocol. Convert to protocol rank value. Similarly, when converting a rank value in the first protocol into a rank value in the third protocol, the protocol conversion unit 34 converts the rank value in the first protocol into an intermediate rank value, and converts the intermediate rank value into the third protocol. 3 protocol rank value. Further, when converting the rank value in the second protocol to the rank value in the first protocol, the protocol conversion unit 34 converts the rank value in the second protocol to an intermediate rank value, and converts the intermediate rank value to the first protocol. Convert to protocol rank value. Similarly, when converting the rank value in the third protocol into the rank value in the first protocol, the protocol conversion unit 34 converts the rank value in the third protocol into an intermediate rank value, and converts the intermediate rank value into the first rank value. 1 protocol rank value.

<Modification 6>
A specific example of a rank value conversion method will be described.
Assume that the wireless communication terminal 10 uses the received signal strength as a metric, and the wireless communication terminal 20 uses the hop count from the collection device 1 as a metric.
When converting from DIO-1 to DIO-2, protocol converter 34 converts the rank value included in DIO-1 to the minimum rank value that increases with each hop in the metric used by wireless communication terminal 20. Convert to a rank value in DIO-2 by dividing by the value. That is, by dividing the received signal strength, which is the rank value included in DIO-1, by the minimum value of the received signal strength that increases with each hop, a value corresponding to the number of hops used as a metric in the wireless communication terminal 20 is obtained. is calculated.
When converting from DIO-2 to DIO-1, the protocol converter 34 sets the rank value included in DIO-2 to the minimum rank value that increases with each hop in the metric used by the wireless communication terminal 10. Multiplying the value converts it to a rank value in DIO-1. That is, by multiplying the number of hops, which is the rank value included in DIO-2, by the minimum value of the received signal strength that increases with each hop, a value corresponding to the received signal strength used as a metric in the wireless communication terminal 10 is obtained. is calculated.
Here, the minimum value of received signal strength that increases with each hop was used. However, any constant may be used instead of the minimum value.

The evaluation index in route selection may be an index relating to the wireless link between the wireless communication terminals as described above, or may be an index relating to the state of the wireless communication terminal. The indicator relating to the state of the wireless communication terminal is, for example, the remaining battery level of the wireless communication terminal or the type of device.

<Modification 7>
In Embodiment 1, each functional component is realized by software. However, as a modification 7, each functional component may be realized by hardware. Regarding this modification 7, the differences from the first embodiment will be described.

The configuration of the wireless communication terminal 30 according to Modification 7 will be described with reference to FIG.
When each functional component is implemented by hardware, radio communication terminal 30 includes electronic circuit 301 instead of processor 300 . The electronic circuit 301 is a dedicated circuit that implements the function of each functional component.

The electronic circuit 301 includes a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, a logic IC, a GA (Gate Array), an ASIC (Application Specific Integrated Circuit), and an FPGA (Field-Programmable Gate Array). is assumed.
Each functional component may be realized by one electronic circuit 301, or each functional component may be distributed to a plurality of electronic circuits 301 and realized.

<Modification 8>
As an eighth modification, some of the functional components may be implemented by hardware, and other functional components may be implemented by software.

The processor 300 and the electronic circuit 301 are called a processing circuit. That is, the function of each functional component is realized by the processing circuit.

Embodiment 2.
Embodiment 2 differs from Embodiment 1 in that a node using a main protocol based on the protocol used by the collection device is preferentially specified as a next-hop node. In the second embodiment, this different point will be explained, and the explanation of the same point will be omitted.

***Description of operation***
In Embodiment 1, in step S310 of FIG. 15 and steps S401 and S408 of FIG. identified as a node.

In Embodiment 2, in step S310 of FIG. 15 and steps S401 and S408 of FIG. as the next-hop node.
For example, the communication system 53 shown in FIG. 7 comprises the collection device 1 and the main protocol is the first protocol. Therefore, the route identification unit 321 preferentially identifies the collection device 1 or the wireless communication terminal 10 that uses the first protocol as the next-hop node.

Specifically, when the route identifying unit 321 receives a DIO message based on the main protocol, it transmits the DIO message based on the main protocol regardless of the rank value calculated from the DIO message based on the other protocol. Identify the node as the next-hop node. That is, when DIO-1 and DIO-2 are received when the main protocol is the first protocol, the route identifying unit 321 identifies the node that transmitted DIO-1 as the next hop node. At this time, if a plurality of DIO-1s are received, the route identifying unit 321 identifies the node that transmitted DIO-1 with the lowest rank value as the next hop node.

*** Effect of Embodiment 2 ***
As described above, the wireless communication terminal 30 according to Embodiment 2 preferentially identifies the node using the main protocol as the next-hop node. As a result, the possibility of conversion of rank values and the like due to differences in protocols can be reduced. As a result, errors in rank values due to conversion are less likely to occur.

***Other Configurations***
<Modification 9>
Nodes using other protocols may be identified as next-hop nodes even when receiving DIO messages based on the primary protocol.
For example, the route identifying unit 321 weights the rank value calculated from the DIO message based on the main protocol such that the value becomes smaller. Then, the route identifying unit 321 identifies the minimum rank value among the rank values calculated from all DIO messages, and identifies the node that transmitted the DIO message with the minimum rank value as the next hop node. This allows nodes using the primary protocol to be preferentially identified as next-hop nodes, while leaving the possibility of nodes using other protocols being identified as next-hop nodes.

<Modification 10>
Embodiment 2 explained the case where the first protocol was the main protocol. However, the secondary protocol may also be the primary protocol. In this case, the node using the second protocol, which is the primary protocol, is preferentially identified as the next-hop node.

<Modification 11>
In the second embodiment, the node using the main protocol, which is the protocol used by the collection device, is preferentially identified as the next-hop node. However, a node that uses a specified protocol rather than the protocol used by the collector may be preferentially identified as the next-hop node. The specified protocol may be specified in advance by an administrator or the like of the communication system 53, or may be specified by the collection device or other device.
Thereby, even if the protocol used by the collection device is unknown, it is possible to preferentially use a specific protocol.

Embodiment 3.
Embodiment 3 differs from Embodiments 1 and 2 in that the DIO message of the transition destination protocol is preferentially transmitted. In the third embodiment, this different point will be explained, and the explanation of the same point will be omitted.

***Description of operation***
In Embodiment 1, in steps S204 and S205 of FIG. 12, steps S402 and S403 of FIG. 18, and steps S409 and S410 of FIG. was broadcast.

In the third embodiment, in steps S204 and S205 of FIG. 12, steps S402 and S403 of FIG. 18, and steps S409 and S410 of FIG. Priority transmission. For example, if the communication system 53 is to be migrated to a wireless mesh network centered on the wireless communication terminal 20, the second protocol used by the wireless communication terminal 20 is the destination protocol.

Specifically, in steps S204 and S205 of FIG. 12, steps S402 and S403 of FIG. 18, and steps S409 and S410 of FIG. to decide. Here, the second protocol will be described as the migration destination protocol.
(1) When only DIO-1 is received, the radio communication terminal 30 broadcasts only DIO-1. (2) When only DIO-2 is received, the radio communication terminal 30 broadcasts DIO-2 and DIO-1 generated by converting DIO-2. (3) When both DIO-1 and DIO-2 are received, the wireless communication terminal 30 discards DIO-1 and discards DIO-2 and DIO-2 generated by converting DIO-2. 1 is broadcast.

More specifically, it is as follows.
In the case of (1), the route specifying unit 321 generates DIO-1, and the communication unit 311 broadcasts DIO-1.
In the case of (2), the route specifying unit 322 generates DIO-2, and the communication unit 312 broadcasts the DIO-2. Also, the protocol converter 34 converts DIO-2 to DIO-1 based on the first protocol. Then, the communication unit 311 broadcasts DIO-1.
Case (3) is the same as case (2). That is, the route specifying unit 322 generates DIO-2, and the communication unit 312 broadcasts the DIO-2. Also, the protocol converter 34 converts DIO-2 to DIO-1 based on the first protocol. Then, the communication unit 311 broadcasts DIO-1.

*** Effect of Embodiment 3 ***
As described above, the wireless communication terminal 30 according to the third embodiment preferentially transmits the DIO message of the destination protocol. This helps facilitate switching to wireless mesh networks using the destination protocol.

Note that "unit" in the above description may be read as "circuit", "process", "procedure", "process", or "processing circuit".

The embodiments and modifications of the present disclosure have been described above. Some of these embodiments and modifications may be combined and implemented. Also, any one or some may be partially implemented. It should be noted that the present disclosure is not limited to the above embodiments and modifications, and various modifications are possible as necessary.

51 communication system, 52 communication system, 53 communication system, 1 collection device, 2 collection device, 10 wireless communication terminal, 20 wireless communication terminal, 30 wireless communication terminal, 100 communication device, 101 antenna, 102 PHY, 103 MAC, 200 communication Device, 201 Antenna, 202 PHY, 203 MAC, 111 Sensor Device, 112 Actuator Device, 113 Clock Calendar, 300 Processor, 31 Communication Unit, 311 Communication Unit, 312 Communication Unit, 32 Route Identification Unit, 321 Route Identification Unit, 322 Route Identification unit 33 Protocol determination unit 34 Protocol conversion unit 341 First rank conversion table 342 First metric conversion table 343 Second rank conversion table 344 Second metric conversion table 900 Memory 910 Auxiliary storage device 920 input interface, 930 output interface;

Claims (14)

A wireless communication terminal that configures a wireless mesh network,
a plurality of communication units corresponding to each of a plurality of protocols;
A message based on a source protocol, which is a protocol used by a source that is another wireless communication terminal that configures the wireless mesh network, is a destination protocol among the plurality of protocols, and configures the wireless mesh network. a protocol conversion unit that converts a message based on a destination protocol used by a destination that is a wireless communication terminal different from the transmission source,
A communication unit corresponding to the destination protocol among the plurality of communication units transmits the message converted by the protocol conversion unit ;
The protocol conversion unit, when the transmission source is a next-hop wireless communication terminal when the transmission destination is a collection device that is a wireless communication terminal that collects data from the wireless mesh network, A radio that converts its own routing control message based on the source protocol generated based on the next hop routing message obtained based on the routing control message to its own routing control message based on the destination protocol, with each of a plurality of protocols as the destination protocol. communication terminal. A wireless communication terminal that configures a wireless mesh network,
a plurality of communication units corresponding to each of a plurality of protocols;
A message based on a source protocol, which is a protocol used by a source that is another wireless communication terminal that configures the wireless mesh network, is a destination protocol among the plurality of protocols, and configures the wireless mesh network. a protocol conversion unit that converts a message based on a destination protocol used by a destination that is a wireless communication terminal different from the transmission source,
A communication unit corresponding to the destination protocol among the plurality of communication units transmits the message converted by the protocol conversion unit ;
When the destination is a next-hop wireless communication terminal in a case where the destination is a collection device that collects data from the wireless mesh network, the protocol conversion unit converts the collection device received from the transmission source to the A wireless communication terminal that converts a connection request message requesting connection to a wireless mesh network into a connection request message based on the destination protocol . 3. The wireless communication terminal according to claim 1, wherein the communication unit corresponding to the transmission source protocol among the plurality of communication units receives the message transmitted from the transmission source wireless communication terminal. the route control message includes a protocol-based evaluation index, which is a route evaluation index in the wireless mesh network;
The protocol conversion unit converts an evaluation index corresponding to the source protocol into an evaluation index corresponding to the destination protocol, thereby converting its own routing control message based on the source protocol to its own route control message based on the destination protocol. 2. The wireless communication terminal of claim 1 , wherein the routing message is converted into a A wireless communication terminal that configures a wireless mesh network,
a plurality of communication units corresponding to each of a plurality of protocols;
A message based on a source protocol, which is a protocol used by a source that is another wireless communication terminal that configures the wireless mesh network, is a destination protocol among the plurality of protocols, and configures the wireless mesh network. a protocol conversion unit that converts a message based on a destination protocol used by a destination that is a wireless communication terminal different from the transmission source,
A communication unit corresponding to the destination protocol among the plurality of communication units transmits the message converted by the protocol conversion unit ;
The protocol conversion unit converts a route evaluation index calculated from a route control message based on one of the plurality of protocols, which is a route control message transmitted from a nearby wireless communication terminal, into a reference format. into a metric of
The wireless communication terminal further
A route identification unit that identifies a next-hop wireless communication terminal from the surrounding wireless communication terminals based on the evaluation index in the form of the reference converted by the protocol conversion unit.
A wireless communication terminal. 6. The route identifying unit preferentially identifies a wireless communication terminal using a main protocol, which is a protocol used by a collecting device that collects data from the wireless mesh network, as the wireless communication terminal of the next hop. The wireless communication terminal described in . The protocol conversion unit receives, from the wireless communication terminal of the next hop, a routing control message of the next hop based on a transition destination protocol among the plurality of protocols, and a route control message of the next hop based on a protocol other than the transition destination protocol. when both the routing control message and the routing control message are received, only the routing control message based on the destination protocol, which is generated based on the routing control message of the next hop based on the destination protocol, is sent to the destination protocol. 2. A wireless communication terminal according to claim 1 , wherein the wireless communication terminal converts its own routing message based on the The protocol converter converts a message based on the source protocol into a message based on the destination protocol, with only a protocol used by a wireless communication terminal constituting the wireless mesh network among the plurality of protocols as the destination protocol. The radio communication terminal according to claim 1. A wireless communication method for configuring a wireless mesh network,
A protocol conversion unit converts a message based on a transmission source protocol, which is a protocol used by a transmission source, which is a wireless communication terminal constituting the wireless mesh network, to a destination protocol among a plurality of protocols, the wireless mesh network. into a message based on a destination protocol used by a destination that is a wireless communication terminal different from the source constituting the
a communication unit corresponding to the destination protocol among the plurality of communication units corresponding to each of the plurality of protocols, transmitting the converted message ;
When the protocol conversion unit is a next-hop wireless communication terminal when the transmission destination is a collection device that is a wireless communication terminal that collects data from the wireless mesh network, the protocol conversion unit is transmitted from the transmission source A radio that converts its own routing control message based on the source protocol generated based on the next hop routing message obtained based on the routing control message to its own routing control message based on the destination protocol, with each of a plurality of protocols as the destination protocol. Communication method. A wireless communication method for configuring a wireless mesh network,
A protocol conversion unit converts a message based on a transmission source protocol, which is a protocol used by a transmission source, which is a wireless communication terminal constituting the wireless mesh network, to a destination protocol among a plurality of protocols, the wireless mesh network. into a message based on a destination protocol used by a destination that is a wireless communication terminal different from the source constituting the
a communication unit corresponding to the destination protocol among the plurality of communication units corresponding to each of the plurality of protocols, transmitting the converted message ;
When the destination is a next-hop wireless communication terminal in the case where the destination is a collection device that collects data from the wireless mesh network, the protocol conversion unit performs the following on the collection device received from the transmission source: A wireless communication method for converting a connection request message requesting connection to a wireless mesh network into a connection request message based on the destination protocol . A wireless communication method for configuring a wireless mesh network,
A protocol conversion unit converts a message based on a transmission source protocol, which is a protocol used by a transmission source, which is a wireless communication terminal constituting the wireless mesh network, to a destination protocol among a plurality of protocols, the wireless mesh network. into a message based on a destination protocol used by a destination that is a wireless communication terminal different from the source constituting the
a communication unit corresponding to the destination protocol among the plurality of communication units corresponding to each of the plurality of protocols, transmitting the converted message ;
The protocol conversion unit converts a route evaluation index calculated from a route control message based on one of the plurality of protocols, which is a route control message transmitted from a nearby wireless communication terminal, into a reference format. into a metric of
A radio communication method, wherein a route identifying unit identifies a next-hop radio communication terminal from the peripheral radio communication terminals based on the evaluation index in the form of the criteria. A wireless communication program for configuring a wireless mesh network,
A message based on a source protocol, which is a protocol used by a source that is a wireless communication terminal that configures the wireless mesh network, is a destination protocol among a plurality of protocols, and the transmission that configures the wireless mesh network. a protocol conversion process for converting the message into a message based on a destination protocol used by a destination that is a wireless communication terminal different from the original;
causing a computer to function as a wireless communication terminal that performs a communication process of transmitting a message converted by the protocol conversion process by a communication part corresponding to the destination protocol among the plurality of communication parts corresponding to the respective protocols; ,
In the protocol conversion process, when the transmission source is a next-hop wireless communication terminal when the transmission destination is a collection device that is a wireless communication terminal that collects data from the wireless mesh network, converts its own routing control message based on the source protocol generated based on the next-hop routing message to its own routing control message based on the destination protocol, with each of the plurality of protocols as the destination protocol. radio communication program. A wireless communication program for configuring a wireless mesh network,
A message based on a source protocol, which is a protocol used by a source that is a wireless communication terminal that configures the wireless mesh network, is a destination protocol among a plurality of protocols, and the transmission that configures the wireless mesh network. a protocol conversion process for converting the message into a message based on a destination protocol used by a destination that is a wireless communication terminal different from the original;
causing a computer to function as a wireless communication terminal that performs a communication process of transmitting a message converted by the protocol conversion process by a communication part corresponding to the destination protocol among the plurality of communication parts corresponding to the respective protocols; ,
In the protocol conversion process, when the destination is a wireless communication terminal of the next hop when the transmission destination is a collection device that collects data from the wireless mesh network, for the collection device received from the transmission source: A wireless communication program for converting a connection request message requesting connection to a wireless mesh network into a connection request message based on the destination protocol . A wireless communication program for configuring a wireless mesh network,
A message based on a source protocol, which is a protocol used by a source that is a wireless communication terminal that configures the wireless mesh network, is a destination protocol among a plurality of protocols, and the transmission that configures the wireless mesh network. a protocol conversion process for converting the message into a message based on a destination protocol used by a destination that is a wireless communication terminal different from the original;
communication processing for transmitting a message converted by the protocol conversion processing by a communication unit corresponding to the destination protocol among the plurality of communication units respectively corresponding to the plurality of protocols;
and
In the protocol conversion process, a route control message transmitted from a nearby wireless communication terminal and calculated from a route control message based on one of the plurality of protocols is converted into a reference format. into a metric of
moreover,
A route specifying process for specifying a next-hop wireless communication terminal from the surrounding wireless communication terminals based on the evaluation index in the standard format converted by the protocol conversion process.
A wireless communication program that makes a computer function as a wireless communication terminal that performs

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