Wireless communication terminal, wireless communication method, and computer-readable storage medium

Abstract

The present application provides a wireless communication terminal, a wireless communication method, and a computer-readable storage medium. A communication system (53) as a wireless mesh network is configured by a wireless communication terminal (10, 20) and a wireless communication terminal (30) using different protocols. The wireless communication terminal (30) is provided with a plurality of communication sections corresponding to a plurality of protocols used by the wireless communication terminal (10, 20) respectively. The wireless communication terminal (30) converts a message based on a protocol used at a transmission source, i.e., a transmission source protocol, into a message based on a protocol used at a destination, i.e., a destination protocol, and transmits the converted message through a communication section corresponding to the destination protocol among the plurality of communication sections.

Description

Technical Field

[0001] This disclosure relates to wireless communication terminals constituting a wireless mesh network. Background Technology

[0002] Wireless mesh networks are used in sensor networks for collecting environmental information and in networks for collecting electricity meter readings based on smart meters. In a wireless mesh network, data collection devices and wireless communication terminals, which act as sub-devices, autonomously build a network through wireless communication.

[0003] As a routing protocol for wireless mesh networks, RPL (IPv6 Routing Protocol for Low Power and Lossy Networks) as described in Non-Patent Document 1 is specified as an Internet standard.

[0004] In the RPL, multiple metrics are defined for path selection, and the settings, which are set as options, vary from installation to installation. Therefore, between nodes conforming to the RPL, the settings of at least one of the metrics and settings may sometimes differ. When settings differ, even nodes conforming to the RPL cannot forward path control messages (DIOs) from the root of the DODAG (Destination-Oriented Directed Acyclic Graph) that serves as the collection device, and thus cannot interact with each other.

[0005] The following requirements exist in wireless mesh networks: it is desirable to achieve high-speed collection cycles or broadband communication while maintaining the data collection function of the existing wireless mesh network.

[0006] Patent Document 1 describes a method for integrating existing and next-generation smart meters in a lookup network of a smart meter. This next-generation smart meter utilizes a communication method that offers higher speeds compared to existing smart meters. In Patent Document 1, the signal strength value used to calculate the path quality value is converted according to the communication method, and a suitable communication path is selected for each communication method. This enables communication between existing and next-generation smart meters. Here, the communication method refers to the communication between the PHY (Physical) layer and the MAC (Medium Access Control) layer.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent No. 6752383

[0010] Non-patent literature

[0011] Non-patent literature 1: IETF RFC6550 "RPL: IPv6 Routing Protocol for Low Power and Lossy Networks" Summary of the Invention

[0012] The problem the invention aims to solve

[0013] Patent Document 1 assumes that the same RPL setting is used in the routing protocol, without assuming the possibility of different RPL settings in the routing protocol. That is, Patent Document 1 does not assume that at least one of the metric and setting values ​​differs between nodes. Between nodes with different metric and setting values, DIO messages as path control messages cannot be forwarded, and paths cannot be constructed. Therefore, the technology described in Patent Document 1 cannot address the situation where next-generation smart meters use RPL settings different from those of existing smart meters.

[0014] The purpose of this disclosure is to enable wireless communication terminals that employ different RPL settings, including at least one of the measurement and setting values, to interconnect.

[0015] means for solving problems

[0016] The wireless communication terminal disclosed herein is a wireless communication terminal constituting a wireless mesh network. The wireless communication terminal includes: multiple communication units, each corresponding to a multiple protocol; and a protocol conversion unit that converts a message based on a source protocol into a message based on a destination protocol among the multiple protocols. The source protocol is a protocol used at the source, which is another wireless communication terminal constituting the wireless mesh network. The destination protocol is a protocol used at the destination, which is a wireless communication terminal constituting the wireless mesh network that is different from the source. The communication unit among the multiple communication units corresponding to the destination protocol sends the message converted by the protocol conversion unit.

[0017] The effects of the invention

[0018] In this disclosure, multiple communication units corresponding to multiple protocols are provided. After converting a message based on a source protocol into a message based on another protocol, the message is transmitted through the communication units corresponding to the other protocols. This enables wireless communication terminals using different protocols that employ at least one of a metric and a setting value to be interconnected. Attached Figure Description

[0019] Figure 1 This is a structural diagram of the communication system 51.

[0020] Figure 2 This is a structural diagram of the wireless communication terminal 10.

[0021] Figure 3 This is a structural diagram of the communication system 52.

[0022] Figure 4 This is a structural diagram of the wireless communication terminal 20.

[0023] Figure 5 This is an explanatory diagram of a case where the wireless communication terminal 10, which constitutes part of the communication system 51, is replaced with the wireless communication terminal 20.

[0024] Figure 6 This is an explanatory diagram of the case where the wireless communication terminal 20, which constitutes part of the communication system 52, is replaced by the wireless communication terminal 10.

[0025] Figure 7 This is a structural diagram of the communication system 53 according to embodiment 1.

[0026] Figure 8 This is a structural diagram of the wireless communication terminal 30 according to Embodiment 1.

[0027] Figure 9 This is a flowchart of the process of adding the wireless communication terminal 30 to the communication system 53 according to embodiment 1.

[0028] Figure 10 It is execution Figure 9 The flowchart shown is a structural diagram of the communication system 53 prior to the processing.

[0029] Figure 11 It is execution Figure 9 The flowchart shown is a structural diagram of the communication system 53 after processing.

[0030] Figure 12 This is a flowchart of the process for maintaining the path after the addition of wireless communication terminal 30 and wireless communication terminal 10i in Implementation Method 1.

[0031] Figure 13 This is a diagram showing an example of the first level conversion table 341 of Embodiment 1.

[0032] Figure 14 This is a diagram illustrating an example of the first metric conversion table 342 of Implementation 1.

[0033] Figure 15This is a flowchart of the process of adding the wireless communication terminal 30 to the communication system 53 according to embodiment 1.

[0034] Figure 16 It is execution Figure 15 The flowchart shown is a structural diagram of the communication system 53 prior to the processing.

[0035] Figure 17 It is execution Figure 15 The flowchart shown is a structural diagram of the communication system 53 after processing.

[0036] Figure 18 This is a flowchart of the process for handling the maintenance path after the addition of wireless communication terminals 10e, 20g, and 30f in Implementation Method 1.

[0037] Figure 19 This is a structural diagram of the communication system 53 in Modified Example 1.

[0038] Figure 20 This is a structural diagram of the wireless communication terminal 30 in Modified Example 2.

[0039] Figure 21 This is a diagram showing an example of the second-level conversion table 343 of variant example 4.

[0040] Figure 22 This is a diagram illustrating an example of the second metric conversion table 344 of variant example 4.

[0041] Figure 23 This is a structural diagram of the wireless communication terminal 30 in Modified Example 7. Detailed Implementation

[0042] Implementation method 1.

[0043] ***Structure Explanation***

[0044] <Structures that become premises>

[0045] Reference Figures 1 to 6 The structure that is a prerequisite for Implementation Method 1 will be explained.

[0046] Reference Figure 1 The structure of the communication system 51 is described.

[0047] The communication system 51 is a wireless multi-hop network consisting of a collection device 1 and multiple wireless communication terminals 10. Figure 1 In the example, wireless communication terminals 10a to 10m are shown as wireless communication terminals 10.

[0048] Reference Figure 2 The structure of the wireless communication terminal 10 will be described.

[0049] The wireless communication terminal 10 adopts the first protocol.

[0050] The wireless communication terminal 10 includes a communication device 100, a sensor device 111, an actuator device 112, a timing calendar 113, a processor 300, a memory 900, an auxiliary storage device 910, an input interface 920, and an output interface 930.

[0051] The communication device 100 is used to communicate with the collection device 1 and other wireless communication terminals 10. The communication device 100 includes an antenna 101 for receiving wireless signals, a PHY 102 for digitizing wireless signals, and a MAC 103 for controlling the MAC layer. The sensor device 111 is a sensing device. The actuator device 112 is a device for operating external devices. The timer / calendar 113 is a device for obtaining the date and time.

[0052] Processor 300 is an IC (Integrated Circuit) that performs processing. Memory 900 is a storage device for temporarily storing data. Auxiliary storage device 910 is a storage device for permanently storing data. Input interface 920 is an interface for inputting data from external sources. Output interface 930 is an interface for outputting data to external sources.

[0053] The wireless communication terminal 10 includes a communication unit 311 and a path determination unit 321 as functional structural elements. An auxiliary storage device 910 stores a program that implements the functions of each functional structural element of the wireless communication terminal 10. This program is read into the memory 900 by the processor 300 and executed by the processor 300. Thus, the functions of each functional structural element of the wireless communication terminal 10 are implemented.

[0054] Reference Figure 3 The structure of the communication system 52 is described.

[0055] The communication system 52 is a wireless multi-hop network consisting of a collection device 2 and multiple wireless communication terminals 20. Figure 3 In the middle, wireless communication terminals 20a to 20m are shown as wireless communication terminals 20.

[0056] Reference Figure 4 The structure of the wireless communication terminal 20 will be described.

[0057] Wireless communication terminal 20 employs a second protocol, which is different from the first protocol employed by wireless communication terminal 10. In embodiment 1, the different protocol refers to RPLs where at least one of the measurement and setting values ​​is set differently. Furthermore, due to the use of a different protocol, wireless communication terminal 20 differs from wireless communication terminal 10 in the following ways.

[0058] The wireless communication terminal 20 replaces the communication device 100 and has a communication device 200 in place of the wireless communication device 200. Figure 2 The wireless communication terminal 10 shown is different. Communication device 200 includes antenna 201, PHY 202, and MAC 203. Communication device 200 uses a different channel than communication device 100.

[0059] The wireless communication terminal 20 has a communication unit 312 and a path determination unit 322 as functional structural elements, replacing the communication unit 311 and the path determination unit 321. Figure 2 The wireless communication terminal 20 shown is different. An auxiliary storage device 910 stores a program that implements the functions of each functional structural element of the wireless communication terminal 20. This program is read into the memory 900 by the processor 300 and executed by the processor 300. Thus, the functions of each functional structural element of the wireless communication terminal 20 are implemented.

[0060] like Figure 5 As shown, when the wireless communication terminal 10, which constitutes part of the communication system 51, is replaced with the wireless communication terminal 20, it is impossible to construct a multi-hop communication path. This is because the wireless communication terminal 10 and the wireless communication terminal 20 use different protocols. In other words, it is because there are differences between the wireless communication terminal 10 and the wireless communication terminal 20, between the communication device 100 and the communication device 200, between the communication unit 311 and the communication unit 312, and between the path determination unit 321 and the path determination unit 322.

[0061] like Figure 6 As shown, even when the wireless communication terminal 20, which constitutes part of the communication system 52, is replaced with the wireless communication terminal 10, it is still impossible to construct a multi-hop communication path.

[0062] <Structure of Implementation Method 1>

[0063] Reference Figure 7 and Figure 8 The structure of Implementation Method 1 will be described.

[0064] Reference Figure 7 The structure of the communication system 53 in Embodiment 1 will be described.

[0065] The communication system 53 is a wireless multi-hop network consisting of a 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.

[0066] Reference Figure 8 The structure of the wireless communication terminal 30 in Embodiment 1 will be described.

[0067] Wireless communication terminal 30 is capable of operating according to both the first protocol adopted by wireless communication terminal 10 and the second protocol adopted by wireless communication terminal 20. Therefore, wireless communication terminal 30 differs from wireless communication terminal 10 and wireless communication terminal 20 in the following ways.

[0068] The wireless communication terminal 30 is similar to having both communication device 100 and communication device 200. Figure 2 The wireless communication terminal 10 shown and Figure 4 The wireless communication terminal 20 shown is different. Furthermore, the wireless communication terminal 30, as a functional structural element, includes a communication unit 31 comprising a communication unit 311 and a communication unit 312, and a path determination unit 32 comprising a path determination unit 321 and a path determination unit 322. Figure 2 The wireless communication terminal 10 shown and Figure 4 The wireless communication terminal 20 shown is different. That is, the wireless communication terminal 30 has a communication device, a communication unit, and a path determination unit that correspond to multiple protocols respectively.

[0069] Furthermore, the wireless communication terminal 30 includes a protocol determination unit 33 and a protocol conversion unit 34 as functional structural elements, which is consistent with... Figure 2 The wireless communication terminal 10 shown and Figure 4 The wireless communication terminal 20 shown is different.

[0070] The auxiliary storage device 910 stores programs that implement the functions of each functional structural element of the wireless communication terminal 30. These programs are read into the memory 900 by the processor 300 and executed by the processor 300. Thus, the functions of each functional structural element of the wireless communication terminal 30 are implemented.

[0071] ***Instructions for the Actions***

[0072] Reference Figures 9 to 18 The operation of the communication system 53 in Implementation 1 will be explained.

[0073] In particular, the operation steps of the wireless communication terminal 30 in the communication system 53 of Embodiment 1 are equivalent to the wireless communication method of Embodiment 1. Furthermore, the program in the communication system 53 of Embodiment 1 that implements the operation of the wireless communication terminal 30 is equivalent to the wireless communication program of Embodiment 1.

[0074] <Add Processing 1>

[0075] Reference Figure 9 The process of adding the wireless communication terminal 30 of Embodiment 1 to the communication system 53 will be described. Figure 9 The image shows the addition of wireless communication terminal 30d. Figure 10The processing added by the wireless communication terminal 10i after the communication system 53 shown.

[0076] Here, as Figure 10 As shown, this is assumed to be a state where there is no wireless communication terminal 20 in the communication system 53.

[0077] First, the action of the wireless communication terminal 30d joining the communication system 53 will be explained.

[0078] (Step S101)

[0079] In wireless communication terminal 30d, path determination unit 321 generates a DIS (DODAG Information Solicitation) message (DIS-1). Then, communication unit 311 broadcasts DIS-1 from communication device 100. Furthermore, path determination unit 322 generates a DIS message (DIS-2). Then, communication unit 312 broadcasts DIS-2 from communication device 200. Additionally, although wireless communication terminal 20 is not present in communication system 53, it is unclear whether wireless communication terminal 20 exists in wireless communication terminal 30d; therefore, DIS-2 is generated.

[0080] The DIS message is a request message for requesting path control messages.

[0081] (Step S102)

[0082] A wireless communication terminal 10a, located near the wireless communication terminal 30d, receives a DIS-1 sent from the wireless communication terminal 30d. In this manner, the path determination unit 321 in the wireless communication terminal 10a generates a DIO (DODAG Information Object) message (DIO-1) based on the DIS-1. Then, the communication unit 311 sends the DIO-1 from the communication device 100 to the wireless communication terminal 30d.

[0083] DIO messages are path control messages. A DIO message contains evaluation metrics for the path in communication system 53. Specifically, the DIO message includes evaluation metrics, or grade values, for the path from collection device 1 to wireless communication terminal 10a.

[0084] (Step S103)

[0085] The communication unit 311 of the wireless communication terminal 30d receives DIO-1 sent from the wireless communication terminal 10a. Thus, 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 processing to the communication unit 311 and the path determination unit 321. Specifically, the protocol determination unit 33 makes a determination based on differences in information contained in the message. For example, the protocol determination unit 33 makes a determination based on the difference between a parameter value of a specified metric contained in the message and a flag contained in the message. Alternatively, the protocol determination unit 33 can also make a determination based on whether the message was received by the communication device 100 or the communication device 200, or based on whether the message was received by the communication unit 311 or the communication unit 312.

[0086] The path determination unit 321 calculates the grade value of the path from the collection device 1 to the wireless communication terminal 30d based on the grade 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 at the time of receiving DIO-1.

[0087] Here, the wireless communication terminal 30d only receives DIO-1 sent from the wireless communication terminal 10a. However, the wireless communication terminal 30d sometimes receives DIO-1 from multiple nodes (any of the collecting device 1, the wireless communication terminal 10, and the wireless communication terminal 30). In this case, the path determination unit 321 takes each DIO-1 as an object, calculates the level value of the path from the collecting device 1 to the wireless communication terminal 30d based on the level value contained in the object DIO-1 and the measurement at the time of reception, and determines the DIO-1 with the smallest level value. Additionally, the case where no DIO message is received from the wireless communication terminal 20 will be explained here.

[0088] Furthermore, the path determination unit 321 identifies the node that sent the determined DIO-1 as the next-hop node when the collection device 1 is the destination. Here, the wireless communication terminal 10a is identified as the next-hop node. The path determination unit 321 generates a DAO (DODAG Advertisement Object) message (DAO-1). Then, the communication unit 311 sends DAO-1 from the communication device 100 to the collection device 1 via the wireless communication terminal 10a, which is the next-hop node.

[0089] The DAO message is a connection request message for the communication system 53. Therefore, the wireless communication terminal 30d sends a connection request to the communication system 53, and the joining action is completed.

[0090] Next, the operation of the wireless communication terminal 10i joining the communication system 53 will be explained.

[0091] (Step S104)

[0092] In the wireless communication terminal 10i, the path determination unit 321 generates a DIS message (DIS-1). Then, the communication unit 311 broadcasts and transmits DIS-1 from the communication device 100.

[0093] (Step S105)

[0094] The communication unit 311 of the wireless communication terminal 30d, located around the wireless communication terminal 10i, receives DIS-1 sent 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 transfers processing to the communication unit 311 and the path determination unit 321. The path determination unit 321 generates a DIO message (DIO-1) based on DIS-1. Then, the communication unit 311 sends DIO-1 from the communication device 100 to the wireless communication terminal 10i.

[0095] (Step S106)

[0096] The communication unit 311 of the wireless communication terminal 10i receives DIO-1 transmitted from the wireless communication terminal 30d. Thus, in the wireless communication terminal 10i, the path determination unit 321 calculates the level value of the path from the collection device 1 to the wireless communication terminal 10i based on the level value contained in DIO-1 and the measurement at the time of reception.

[0097] Here, the wireless communication terminal 10i only receives DIO-1 transmitted from the wireless communication terminal 30d. However, the wireless communication terminal 10i sometimes receives DIO-1 from multiple nodes (any one of the collection device 1, the wireless communication terminal 10, and the wireless communication terminal 30). In this case, the path determination unit 321 takes each DIO-1 as an object, calculates the level value of the path from the collection device 1 to the wireless communication terminal 10i based on the level value contained in the object DIO-1 and the measurement at the time of reception, and determines the DIO-1 with the smallest level value.

[0098] Then, the path determination unit 321 determines the node that sent the determined DIO-1 as the next-hop node when the collection device 1 is the destination. Here, the wireless communication terminal 30d is determined as the next-hop node. The path determination unit 321 generates a DAO message (DAO-1). Then, the communication unit 311 sends DAO-1 from the communication device 100 to the collection device 1 via the wireless communication terminal 30d, which is the next-hop node.

[0099] Therefore, the wireless communication terminal 10i makes a connection request to the communication system 53, and the connection action is completed. As a result, a connection is established. Figure 11 The communication system 53 shown.

[0100] As described above, when the wireless communication terminal 30d joins the communication system 53, it uses the communication device 100 and the communication unit 311 to transmit DIS-1 generated by the path determination unit 321, and uses the communication device 200 and the communication unit 312 to transmit DIS-2 generated by the path determination unit 321. This allows it to search for connectable wireless communication terminals. Then, the wireless communication terminal 30d determines, via the protocol determination unit 33, that the received DIO message corresponds to the first protocol, and transfers the processing to the communication unit 311 and the path determination unit 321. Thus, the wireless communication terminal 30d can join the communication system 53 through the same operation as the wireless communication terminal 10.

[0101] <Maintenance Process 1>

[0102] Reference Figure 12 This will be used to explain the maintenance path processing after the addition of wireless communication terminal 30d and wireless communication terminal 10i in Implementation Method 1. Figure 12 In, it is shown Figure 11 The processing of maintenance paths for wireless communication terminals 10a, 30d, and 10i in the communication system 53 shown.

[0103] Here, as Figure 11 As shown, this is assumed to be a state where there is no wireless communication terminal 20 in the communication system 53.

[0104] First, the operation of path maintenance performed by the wireless communication terminal 10a will be explained.

[0105] (Step S201)

[0106] In the wireless communication terminal 10a, when the trickle timer specified by RFC 6206 expires, the path determination unit 321 sets the DIO-1 received so far as the target DIO-1. The path determination unit 321 calculates the level value of the path from the collection device 1 to the wireless communication terminal 10a based on the level value contained in the target DIO-1 and the measurement at the time of reception.

[0107] Then, the path determination unit 321 determines the minimum level value of DIO-1. The path determination unit 321 identifies the node that sent the determined DIO-1 (any one of the collection device 1, wireless communication terminal 10, and wireless communication terminal 30) as the next-hop node when the collection device 1 is the transmission destination. Here, the collection device 1 is identified as the next-hop node. The path determination unit 321 generates a DAO message (DAO-1). Then, the communication unit 311 sends the DAO-1 from the communication device 100 to the collection device 1, which is the next-hop node.

[0108] (Step S202)

[0109] In the wireless communication terminal 10a, the path determination unit 321 generates a DIO message (DIO-1). Then, the communication unit 311 broadcasts the DIO-1 from the communication device 100.

[0110] Next, the operation of path maintenance performed by the wireless communication terminal 30d will be explained.

[0111] (Step S203)

[0112] Similarly, in the wireless communication terminal 30d, when the trickle timer expires, the path determination unit 321 sets the DIO-1 received so far as the target DIO-1. The path determination unit 321 calculates the level value of the path from the collection device 1 to the wireless communication terminal 30d based on the level value contained in the target DIO-1 and the measurement at the time of reception.

[0113] Then, the path determination unit 321 determines the node that sent the determined DIO-1 (any of the collection device 1, wireless communication terminal 10, and wireless communication terminal 30) as the next-hop node when the collection device 1 is the destination. Here, wireless communication terminal 10a is determined as the next-hop node. The path determination unit 321 generates a DAO message (DAO-1). Then, the communication unit 311 sends DAO-1 from the communication device 100 to the collection device 1 via the wireless communication terminal 10a, which is the next-hop node.

[0114] (Step S204)

[0115] In the wireless communication terminal 30d, the path determination unit 321 generates a DIO message (DIO-1). Then, the communication unit 311 broadcasts the DIO-1 from the communication device 100.

[0116] (Step S205)

[0117] In the wireless communication terminal 30d, the protocol conversion unit 34 converts the 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.

[0118] Specifically, the protocol conversion unit 34 converts DIO-1 into DIO-2 by converting the evaluation metrics based on the first protocol contained in DIO-1 into evaluation metrics based on the second protocol. That is, the protocol conversion unit 34 converts DIO-1 into DIO-2 by converting the level values ​​based on the first protocol into level values ​​based on the second protocol. In other words, the protocol conversion unit 34 converts the scale of the level values ​​in the first protocol into the scale of the level values ​​in the second protocol.

[0119] For example, the protocol conversion unit 34 refers to Figure 13 The first-level conversion table 341 and shown Figure 14 Use any of the squares in the first metric conversion table 342 shown to convert rank values ​​and metrics. Figure 13 In the first protocol, a Link Quality Level (LQL) is used to evaluate the wireless link based on Received Signal Strength Indicator (RSSI). If the signal strength is -90 dBm or higher, a level value of 128 is assigned; if the signal strength is -120 dBm or higher but less than -90 dBm, a level value of 512 is assigned; and if the signal strength is less than -120 dBm, a level value of 4096 is assigned. On the other hand, in the second protocol, a level value (continuous value) based on packet arrival rate using ETX (Expected Transmission Count) as defined in RFC 6551 is used. Since ETX is not measured in the first protocol, it needs to be converted to the level value of the second protocol. Therefore, the protocol conversion unit 34... Figure 13 The table derives the ETX rating values ​​based on the RSSI measured in Protocol 1.

[0120] Protocol conversion unit 34 can also be omitted. Figure 13 Such a conversion table, and using Figure 14 The conversion formula between LQL level values ​​and EXT level values.

[0121] Next, the operation of path maintenance performed by the wireless communication terminal 10i will be explained.

[0122] (Step S206)

[0123] Similarly, in the wireless communication terminal 10i, when the trickle timer expires, the path determination unit 321 sets the DIO-1 received so far as the target DIO-1. The path determination unit 321 calculates the level value of the path from the collection device 1 to the wireless communication terminal 10i based on the level value contained in the target DIO-1 and the measurement at the time of reception.

[0124] Then, the path determination unit 321 determines the node that sent the determined DIO-1 (any of the collection device 1, wireless communication terminal 10, and wireless communication terminal 30) as the next-hop node when the collection device 1 is the transmission destination. Here, the wireless communication terminal 30d is determined as the next-hop node. The path determination unit 321 generates a DAO message (DAO-1). Then, the communication unit 311 sends DAO-1 from the communication device 100 to the collection device 1 via the wireless communication terminal 30d, which is the next-hop node.

[0125] (Step S207)

[0126] In the wireless communication terminal 10i, the path determination unit 321 generates a DIO message (DIO-1). Then, the communication unit 311 broadcasts the DIO-1 from the communication device 100.

[0127] As described above, when maintaining the path, the wireless communication terminal 30d transmits DIO-1 based on the first protocol and DIO-2 based on the second protocol, obtained by converting DIO-1. That is, the wireless communication terminal 30d transmits DIO-1 based on the source transmission protocol (first protocol) used in the next-hop wireless communication terminal 10a, and transmits DIO-2 based on a protocol other than the first protocol (second protocol). Thus, the wireless communication terminal 30d maintains the communication system 53 it has joined.

[0128] <Add Processing 2>

[0129] Reference Figure 15 The process of adding the wireless communication terminal 30 to the communication system 53 according to Embodiment 1 will be described. Figure 15 In, it is shown in Figure 16 The communication system 53 shown includes the sequential addition of wireless communication terminals 10e, 20g, and 30f.

[0130] Here, unlike the addition process 1, it becomes a state where a wireless communication terminal 20 exists midway in the communication system 53.

[0131] First, the operation of wireless communication terminal 10e joining communication system 53 will be explained.

[0132] (Step S301)

[0133] In the wireless communication terminal 10e, the path determination unit 321 generates a DIS message (DIS-1). Then, the communication unit 311 broadcasts and transmits DIS-1 from the communication device 100.

[0134] (Step S302)

[0135] The communication unit 311 of the wireless communication terminal 30b, located around the wireless communication terminal 10e, receives DIS-1 sent 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 transfers processing to the communication unit 311 and the path determination unit 321. The path determination unit 321 generates a DIO message (DIO-1) based on DIS-1. Then, the communication unit 311 sends DIO-1 from the communication device 100 to the wireless communication terminal 10e.

[0136] (Step S303)

[0137] The communication unit 311 of the wireless communication terminal 10e receives DIO-1 sent from the wireless communication terminal 30b. Thus, in the wireless communication terminal 10e, the path determination unit 321 calculates the level value of the path from the collection device 1 to the wireless communication terminal 10e based on the level value contained in DIO-1 and the measurement at the time of reception.

[0138] Here, wireless communication terminal 10e only receives DIO-1 transmitted from wireless communication terminal 30b. However, wireless communication terminal 10e sometimes receives DIO-1 from multiple nodes (any one of collection device 1, wireless communication terminal 10, and wireless communication terminal 30). In this case, path determination unit 321 takes each DIO-1 as an object, calculates the level value of the path from collection device 1 to wireless communication terminal 10e based on the level value contained in the object DIO-1 and the measurement at the time of reception, and determines the DIO-1 with the smallest level value.

[0139] Then, the path determination unit 321 determines the node that sent the determined DIO-1 as the next-hop node when the collection device 1 is the destination. Here, the wireless communication terminal 30b is determined as the next-hop node. The path determination unit 321 generates a DAO message (DAO-1). Then, the communication unit 311 sends DAO-1 from the communication device 100 to the collection device 1 via the wireless communication terminal 30b, which is the next-hop node.

[0140] Therefore, the wireless communication terminal 10e makes a connection request to the communication system 53, and the joining action is completed.

[0141] Next, the operation of the wireless communication terminal 20g joining the communication system 53 will be explained.

[0142] (Step S304)

[0143] In the wireless communication terminal 20g, the path determination unit 322 generates a DIS message (DIS-2). Then, the communication unit 312 broadcasts DIS-2 from the communication device 200.

[0144] (Step S305)

[0145] The communication unit 312 of the wireless communication terminal 30b, located around the wireless communication terminal 20g, receives DIS-2 sent from the wireless communication terminal 20g. In the wireless communication terminal 30b, the protocol determination unit 33 determines that DIS-2 is a message based on the second protocol and transfers the processing to the communication unit 312 and the path determination unit 322.

[0146] The path determination unit 322 generates a DIO message (DIO-2) based on DIS-2. At this time, the protocol conversion unit 34 converts the level value from the collection device 1 to the wireless communication terminal 30b into a level value based on the second protocol. The path determination unit 322 generates a DIO-2 containing the level value converted by the protocol conversion unit 34. Then, the communication unit 312 sends the DIO-2 from the communication device 200 to the wireless communication terminal 20g.

[0147] (Step S306)

[0148] The communication unit 312 of the wireless communication terminal 20g receives DIO-2 sent from the wireless communication terminal 30b. Thus, in the wireless communication terminal 20g, the path determination unit 322 calculates the level value of the path from the collection device 1 to the wireless communication terminal 20g based on the level value contained in DIO-2 and the measurement at the time of reception.

[0149] Here, the wireless communication terminal 20g only receives DIO-2 transmitted from the wireless communication terminal 30b. However, the wireless communication terminal 20g sometimes receives DIO-2 from multiple nodes (either the wireless communication terminal 20 or the wireless communication terminal 30). In this case, the path determination unit 322 takes each DIO-2 as an object, calculates the level value of the path from the collection device 1 to the wireless communication terminal 20g based on the level value contained in the object DIO-2 and the measurement at the time of reception, and determines the DIO-2 with the smallest level value.

[0150] Then, the path determination unit 322 determines the node that sent the determined DIO-2 as the next-hop node when the collection device 1 is the transmission destination. Here, the wireless communication terminal 30b is determined as the next-hop node. The path determination unit 322 generates a DAO message (DAO-2).

[0151] Then, the communication unit 312 sends DAO-2 from the communication device 200 to the collection device 1 via the wireless communication terminal 30b, which serves as the next-hop node. As a result, the wireless communication terminal 20g makes a connection request to the communication system 53, and the joining operation is completed.

[0152] Furthermore, at this time, in the wireless communication terminal 30b, when the communication unit 312 receives DAO-2 sent by the wireless communication terminal 20g, the protocol determination unit 33 determines that DAO-2 is a message based on the second protocol. Thus, the protocol conversion unit 34 converts the DAO-2 based on the second protocol into DAO-1 based on the first protocol used in the collection device 1, which is the next hop of the wireless communication terminal 30b. Then, the communication unit 311 sends DAO-1 from the communication device 100 to the collection device 1.

[0153] Next, the operation of the wireless communication terminal 30f joining the communication system 53 will be explained.

[0154] (Step S307)

[0155] In the wireless communication terminal 30f, the path determination unit 321 generates a DIS message (DIS-1). Then, the communication unit 311 broadcasts DIS-1 from the communication device 100. Furthermore, the path determination unit 322 generates a DIS message (DIS-2). Then, the communication unit 312 broadcasts DIS-2 from the communication device 200.

[0156] (Step S308)

[0157] Wireless communication terminals 30b and 10e, located around wireless communication terminal 30f, receive DIS-1 transmitted from wireless communication terminal 30f. In wireless communication terminal 30b, path determination unit 321 generates a DIO message (DIO-1) based on DIS-1. Then, communication unit 311 transmits DIO-1 from communication device 100 to wireless communication terminal 30f. Similarly, in wireless communication terminal 10e, path determination unit 321 generates a DIO message (DIO-1) based on DIS-1. Then, communication unit 311 transmits DIO-1 from communication device 100 to wireless communication terminal 30f.

[0158] Here, in DIO-1, there are level values ​​based on the first protocol.

[0159] (Step S309)

[0160] Wireless communication terminals 30b and 20g, located around wireless communication terminal 30f, receive DIS-2 transmitted from wireless communication terminal 30f. In wireless communication terminal 30b, path determination unit 322 generates a DIO message (DIO-2) based on DIS-2. Then, communication unit 312 transmits DIO-2 from communication device 200 to wireless communication terminal 30f. Similarly, in wireless communication terminal 20g, path determination unit 322 generates a DIO message (DIO-2) based on DIS-2. Then, communication unit 312 transmits DIO-2 from communication device 200 to wireless communication terminal 30f.

[0161] Here, in DIO-2, there are level values ​​based on the second protocol.

[0162] (Step S310)

[0163] The communication unit 311 of the wireless communication terminal 30f receives DIO-1 messages sent from the wireless communication terminal 30b and the wireless communication terminal 10e. Thus, in the wireless communication terminal 30f, the protocol determination unit 33 determines that the two DIO-1 messages are based on the first protocol and transfers the processing to the communication unit 311 and the path determination unit 321. The path determination unit 321 treats each of the two DIO-1 messages as an object and calculates the path grade value from the collection device 1 to the wireless communication terminal 30f based on the grade value contained in the object's DIO-1 message and the measurement at the time of reception.

[0164] The communication unit 312 of the wireless communication terminal 30f receives DIO-2 sent from the wireless communication terminal 30b and the wireless communication terminal 20g. Thus, in the wireless communication terminal 30f, the protocol determination unit 33 determines that the two DIO-2 messages are based on the second protocol and transfers the processing to the communication unit 312 and the path determination unit 322. The path determination unit 322 treats each DIO-2 as a target and calculates the path grade value from the collection device 1 to the wireless communication terminal 30f based on the grade value contained in the target DIO-2 and the measurement at the time of reception.

[0165] The protocol conversion unit 34 of the wireless communication terminal 30f converts the calculated grade value into a reference form grade value. This allows for comparison between the grade value based on the first protocol and the grade value based on the second protocol.

[0166] Here, the protocol conversion unit 34 refers to the first level conversion table 341 and converts the level value calculated based on the second protocol according to DIO-2 into a level value based on the first protocol. Then, the path determination unit 321 compares the two level values ​​calculated based on two DIO-1s with the two converted level values ​​calculated based on two DIO-2s, and determines the DIO-1 or DIO-2 that has the smallest level value. The path determination unit 321 determines the node that sent the determined DIO-1 or DIO-2 as the next-hop node when the collection device 1 is the transmission destination. Here, since DIO-1 is determined from the wireless communication terminal 30b, the communication device 100 of the wireless communication terminal 30b is determined as the next-hop node.

[0167] The path determination unit 321 generates a DAO message (DAO-1). Then, the communication unit 311 sends DAO-1 from the communication device 100 to the collection device 1 via the communication device 100 of the wireless communication terminal 30b, which serves as the next hop node. At this time, when the wireless communication terminal 30b receives DAO-1, ​​the protocol determination unit 33 determines that it is a message based on the first protocol and sends it to the collection device 1 via the communication unit 311.

[0168] Therefore, the wireless communication terminal 30f makes a connection request to the communication system 53, and the connection action is completed. As a result, a connection is established. Figure 17 The communication system 53 shown.

[0169] Here, the level value based on protocol 2 is converted to a level value based on protocol 1. However, it is also possible to convert a level value based on protocol 1 to a level value based on protocol 2. Furthermore, it is also possible to convert level values ​​based on protocol 1 and protocol 2 into a common form.

[0170] Furthermore, here, the level value is converted after calculating the level value of the path from the collection device 1 to the wireless communication terminal 30f. However, the level value of the path from the collection device 1 to the wireless communication terminal 30f can also be calculated after converting the level value contained in at least one of DIO-1 and DIO-2.

[0171] As described above, wireless communication terminal 20g can join communication system 53 via wireless communication terminal 30b.

[0172] Furthermore, the wireless communication terminal 30f can compare at least one of the grade value based on the first protocol and the grade value based on the second protocol. Therefore, even when receiving DIO messages based on multiple protocols, the next-hop node can be determined.

[0173] <Maintenance Processing 2>

[0174] Reference Figure 18 This will be used to explain the maintenance path processing after the addition of wireless communication terminals 10e, 20g, and 30f in Implementation Method 1. Figure 18 In, it is shown Figure 17 The communication system 53 shown includes the processing of maintenance paths for wireless communication terminals 30b, 10e, 20g, and 30f.

[0175] First, let's explain the path maintenance operation performed by the wireless communication terminal 30b.

[0176] (Step S401)

[0177] In the wireless communication terminal 30b, when the trickle timer expires, the path determination unit 321 sets each of the currently received DIO-1s as target DIO-1s. The path determination unit 321 calculates the grade value of the path from the collection device 1 to the wireless communication terminal 30b based on the grade value contained in the target DIO-1s and the measurement at the time of reception. Furthermore, the path determination unit 322 sets each of the currently received DIO-2s as target DIO-2s. The path determination unit 322 calculates the grade value of the path from the collection device 1 to the wireless communication terminal 30b based on the grade value contained in the target DIO-2s and the measurement at the time of reception.

[0178] Protocol conversion unit 34 converts the calculated level value into a base-form level value. The conversion method is the same as... Figure 15 The process in step S310 is the same. The path determination unit 321 determines either DIO-1 or DIO-2, which is the minimum level value. The path determination unit 321 determines the node that sent the determined DIO-1 or DIO-2 (any one of the collection device 1, wireless communication terminal 10, wireless communication terminal 20, and wireless communication terminal 30) as the next-hop node when the collection device 1 is the destination. Here, the collection device 1 is determined as the next-hop node. The path determination unit 321 generates a DAO message (DAO-1). Then, the communication unit 311 sends DAO-1 from the communication device 100 to the collection device 1, which is the next-hop node.

[0179] (Step S402)

[0180] In the wireless communication terminal 30b, the path determination unit 321 generates a DIO message (DIO-1). Then, the communication unit 311 broadcasts the DIO-1 from the communication device 100.

[0181] (Step S403)

[0182] In the wireless communication terminal 30b, the protocol conversion unit 34 converts the 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. The specific conversion method is similar to... Figure 12 The conversion method in step S205 is the same.

[0183] Next, the operation of path maintenance performed by the wireless communication terminal 10e will be explained.

[0184] (Step S404)

[0185] Similarly, in the wireless communication terminal 10e, when the trickle timer expires, the path determination unit 321 sets the DIO-1 received so far as the target DIO-1. The path determination unit 321 calculates the level value of the path from the collection device 1 to the wireless communication terminal 10e based on the level value contained in the target DIO-1 and the measurement at the time of reception.

[0186] Then, the path determination unit 321 determines the node that sent the determined DIO-1 (any of the collection device 1, wireless communication terminal 10, and wireless communication terminal 30) as the next-hop node when the collection device 1 is the transmission destination. Here, wireless communication terminal 30b is determined as the next-hop node. The path determination unit 321 generates a DAO message (DAO-1). Then, the communication unit 311 sends DAO-1 from the communication device 100 to the collection device 1 via the wireless communication terminal 30b, which is the next-hop node.

[0187] (Step S405)

[0188] In the wireless communication terminal 10e, the path determination unit 321 generates a DIO message (DIO-1). Then, the communication unit 311 broadcasts the DIO-1 from the communication device 100.

[0189] Next, the operation of path maintenance performed by the wireless communication terminal 20g will be explained.

[0190] (Step S406)

[0191] Similarly, in the wireless communication terminal 20g, the path determination unit 322 sets the DIO-2 received so far as the target DIO-2 when the trickle timer expires. The path determination unit 322 calculates the level value of the path from the collection device 1 to the wireless communication terminal 20g based on the level value contained in the target DIO-2 and the measurement at the time of reception.

[0192] Then, the path determination unit 322 determines the node (either of wireless communication terminal 20 or wireless communication terminal 30) that sent the determined DIO-2 as the next-hop node when the collection device 1 is the transmission destination. Here, wireless communication terminal 30b is determined as the next-hop node. The path determination unit 321 generates a DAO message (DAO-2). Then, the communication unit 311 sends DAO-2 from the communication device 200 to the collection device 1 via the wireless communication terminal 30b, which is the next-hop node.

[0193] Furthermore, at this time, in the wireless communication terminal 30b, when the communication unit 312 receives DAO-2 sent by the wireless communication terminal 20g, the protocol determination unit 33 determines that DAO-2 is a message based on the second protocol. Thus, the protocol conversion unit 34 converts the DAO-2 based on the second protocol into DAO-1 based on the first protocol used in the collection device 1, which is the next hop of the wireless communication terminal 30b. Then, the communication unit 311 sends DAO-1 from the communication device 100 to the collection device 1.

[0194] (Step S407)

[0195] In the wireless communication terminal 20g, the path determination unit 322 generates a DIO message (DIO-2). Then, the communication unit 312 broadcasts DIO-2 from the communication device 200.

[0196] Next, the operation of path maintenance performed by the wireless communication terminal 30f will be explained.

[0197] (Step S408)

[0198] In the wireless communication terminal 30f, when the trickle timer expires, the path determination unit 321 sets each of the currently received DIO-1s as target DIO-1s. The path determination unit 321 calculates the grade value of the path from the collection device 1 to the wireless communication terminal 30f based on the grade value contained in the target DIO-1s and the measurement at the time of reception. Furthermore, the path determination unit 322 sets each of the currently received DIO-2s as target DIO-2s. The path determination unit 322 calculates the grade value of the path from the collection device 1 to the wireless communication terminal 30f based on the grade value contained in the target DIO-2s and the measurement at the time of reception.

[0199] Protocol conversion unit 34 converts the calculated level value into a base-form level value. The conversion method is the same as... Figure 15 The process in step S310 is the same. The path determination unit 321 determines either DIO-1 or DIO-2, which is the minimum level value. The path determination unit 321 determines the node that sent the determined DIO-1 or DIO-2 (any one of the collection device 1, wireless communication terminal 10, wireless communication terminal 20, and wireless communication terminal 30) as the next-hop node when the collection device 1 is the destination. Here, the communication device 100 of the wireless communication terminal 30b is determined as the next-hop node. The path determination unit 321 generates a DAO message (DAO-1). Then, the communication unit 311 sends 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.

[0200] (Step S409)

[0201] In the wireless communication terminal 30f, the path determination unit 321 generates a DIO message (DIO-1). Then, the communication unit 311 broadcasts the DIO-1 from the communication device 100.

[0202] (Step S410)

[0203] In the wireless communication terminal 30f, the protocol conversion unit 34 converts the 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. The specific conversion method is similar to... Figure 12 The conversion method in step S205 is the same.

[0204] As described above, when maintaining the path, wireless communication terminals 30b and 30f transmit DIO-1 based on the first protocol and DIO-2 based on the second protocol after converting DIO-1. That is, wireless communication terminals 30b and 30f transmit DIO-1 based on the source transmission protocol (first protocol) used in the next-hop wireless communication terminal 10a, and transmit DIO-2 based on a protocol other than the first protocol (second protocol). Thus, wireless communication terminals 30b and 30f maintain the communication system 53 they have joined.

[0205] ***Effects of Implementation Method 1***

[0206] As described above, the wireless communication terminal 30 of Embodiment 1 includes multiple communication units corresponding to multiple protocols respectively. After converting a message based on the source transmission protocol into a message based on another protocol, it transmits the message through the communication units corresponding to the other protocols. Therefore, wireless communication terminals using different settings for at least one of the measurement and setting values ​​can be interconnected.

[0207] Furthermore, the wireless communication terminal 30 in Implementation 1 compares the grade values ​​calculated based on path control messages of various protocols (based on multiple protocols) after converting them into a reference form, thereby determining the minimum grade value. Thus, even when receiving DIO messages based on multiple protocols, the next-hop node can be determined.

[0208] ***Other Structures***

[0209] <Variation Example 1>

[0210] In Embodiment 1, a communication system 53 consisting of a collection device 1, a wireless communication terminal 10, a wireless communication terminal 20, and a wireless communication terminal 30 was described. However, as... Figure 19As shown, it can also replace the collection device 1, and the communication system 53 can be formed by the collection device 2.

[0211] In this case, similar to Embodiment 1, the DIO message and DAO message are converted by the wireless communication terminal 30, and the wireless communication terminal 10, which uses a first protocol different from the second protocol used in the collection device 2, can be added to the communication system 53.

[0212] <Variation Example 2>

[0213] In Embodiment 1, the wireless communication terminal 30 includes both a communication device 100 and a communication device 200. There are also cases where the communication device 100 and the communication device 200 use the same channel. In this case, such as... Figure 20 As shown, the wireless communication terminal 30 can also be configured to have a communication device 500 that uses the same channel as the communication devices 100 and 200, instead of the communication devices 100 and 200. This reduces the number of communication devices included in the wireless communication terminal 30.

[0214] Furthermore, in this case, it is impossible to determine which protocol the message is based on based on which of the communication devices 100 and 200 received the message. However, as described in Embodiment 1, it is possible to determine which protocol it is based on based on the content of the message.

[0215] <Variation Example 3>

[0216] In implementation method 1, Figure 12 Steps S204 and S205 Figure 18 Steps S402 and S403, and Figure 18 In steps S409 and S410, the wireless communication terminal 30 broadcasts DIO-1 and DIO-2.

[0217] However, if the wireless communication terminal 30 is aware that the protocol of the non-using party is not in use, it only needs to broadcast a DIO message based on the protocol of the using party. For example, if it is clear that there is no wireless communication terminal 10 using the first protocol, the wireless communication terminal 30 only needs to broadcast DIO-2.

[0218] <Variation Example 4>

[0219] In Embodiment 1, the protocol conversion unit 34 converts DIO-1 to DIO-2 by referring to the first level conversion table 341 and the first metric conversion table 342. When converting DIO-2 to DIO-1, the protocol conversion unit 34 refers to... Figure 21 The second-level conversion table 343 and shown Figure 22Either of the two methods in the second metric conversion table 344 shown can be used. Thus, similar to the case of converting DIO-1 to DIO-2, it is possible to convert DIO-2 to DIO-1.

[0220] <Variation Example 5>

[0221] In Implementation 1, the wireless communication terminal 10 using the first protocol and the wireless communication terminal 20 using the second protocol are interconnected using the wireless communication terminal 30. However, even when there are wireless communication terminals using three or more protocols, they can be interconnected using the same approach.

[0222] That is, the wireless communication terminal 30 has a communication unit 31, a path determination unit 32 and a communication device corresponding to each protocol, and can connect to each other even when there are wireless communication terminals using more than three protocols, by converting messages into messages of each protocol.

[0223] When using more than three protocols, intermediate level values ​​are defined for conversion purposes. A conversion table between the level values ​​in each protocol and the intermediate level values ​​is prepared in advance, thereby enabling the conversion of level values ​​used in each protocol.

[0224] That is, when converting a level value in the first protocol to a level value in the second protocol, the protocol conversion unit 34 converts the level value in the first protocol to an intermediate level value, and then converts the intermediate level value to a level value in the second protocol. Similarly, when converting a level value in the first protocol to a level value in the third protocol, the protocol conversion unit 34 converts the level value in the first protocol to an intermediate level value, and then converts the intermediate level value to a level value in the third protocol. Furthermore, when converting a level value in the second protocol to a level value in the first protocol, the protocol conversion unit 34 converts the level value in the second protocol to an intermediate level value, and then converts the intermediate level value to a level value in the first protocol. Similarly, when converting a level value in the third protocol to a level value in the first protocol, the protocol conversion unit 34 converts the level value in the third protocol to an intermediate level value, and then converts the intermediate level value to a level value in the first protocol.

[0225] <Variation Example 6>

[0226] A specific example illustrating the method for converting grade values ​​is provided.

[0227] Wireless communication terminal 10 uses the received signal strength as a metric, while wireless communication terminal 20 uses the number of hops from collection device 1 as a metric.

[0228] In the case of transitioning from DIO-1 to DIO-2, the protocol conversion unit 34 converts the level value in DIO-2 by dividing the level value contained in DIO-1 by the minimum value of the level value that increases with each hop in the metric used by the wireless communication terminal 20. That is, by dividing the level value contained in DIO-1, i.e., the received signal strength, by the minimum value of the received signal strength that increases with each hop, a value equivalent to the number of hops used as a metric in the wireless communication terminal 20 is calculated.

[0229] In the case of switching from DIO-2 to DIO-1, the protocol conversion unit 34 converts the level value contained in DIO-2 to the minimum value of the level value that increases per hop in the metric used by the wireless communication terminal 10, thereby converting it to the level value in DIO-1. That is, by multiplying the level value contained in DIO-2, i.e., the number of hops, by the minimum value of the received signal strength that increases per hop, a value equivalent to the received signal strength used as a metric in the wireless communication terminal 10 is calculated.

[0230] Here, the minimum increase in received signal strength per hop is used. However, any constant can be used instead of the minimum.

[0231] In addition, evaluation metrics for path selection can be those related to the wireless link between wireless communication terminals, as mentioned above, or metrics related to the status of the wireless communication terminals. Examples of metrics related to the status of wireless communication terminals include the remaining battery power or the type of device.

[0232] <Variation Example 7>

[0233] In Implementation Example 1, each functional structural element is implemented in software. However, as a variation 7, each functional structural element can also be implemented in hardware. The differences between this variation 7 and Implementation Example 1 will be explained.

[0234] Reference Figure 23 The structure of the wireless communication terminal 30 in Modified Example 7 will be described.

[0235] When all functional structural elements are implemented in hardware, the wireless communication terminal 30 replaces the processor 300 and has electronic circuit 301. Electronic circuit 301 is a dedicated circuit that implements the functions of each functional structural element.

[0236] As an electronic circuit 301, it assumes single circuits, composite circuits, programmable processors, parallel programmable processors, logic ICs, GA (Gate Array), ASIC (Application Specific Integrated Circuit), and FPGA (Field-Programmable Gate Array).

[0237] Each functional structural element can be implemented by a single electronic circuit 301, or the functional structural elements can be distributed among multiple electronic circuits 301.

[0238] <Variation Example 8>

[0239] As a variation of Example 8, some of the functional structural elements can be implemented in hardware, while other functional structural elements can be implemented in software.

[0240] The processor 300 and electronic circuit 301 are referred to as the processing circuit. That is, the functions of each functional structural element are implemented by the processing circuit.

[0241] Implementation method 2.

[0242] The difference between Embodiment 2 and Embodiment 1 is that nodes using the main protocol based on the protocol used in the collection device are preferentially determined as the next-hop nodes. In Embodiment 2, this difference will be explained, while the similarities will be omitted.

[0243] ***Instructions for the Actions***

[0244] In implementation method 1, Figure 15 Step S310, and Figure 18 In steps S401 and S408, the path determination unit 321 determines the node that has sent the minimum level value DIO-1 or DIO-2 as the next hop node.

[0245] In implementation method 2, Figure 15 Step S310, and Figure 18 In steps S401 and S408, the path determination unit 321 preferentially determines the node of the next hop using the main protocol based on the protocol used by the collection device in the communication system 53.

[0246] For example, Figure 7 The communication system 53 shown includes a collection device 1, and the main protocol is the first protocol. Therefore, the path determination unit 321 preferentially determines the collection device 1 or the wireless communication terminal 10 using the first protocol as the next hop node.

[0247] Specifically, when the path determination unit 321 receives a DIO message based on the main protocol, it determines the node that sent the DIO message based on the main protocol as the next-hop node, regardless of the rank value calculated based on DIO messages based on other protocols. That is, when the main protocol is Protocol 1, upon receiving DIO-1 and DIO-2, the path determination unit 321 determines the node that sent DIO-1 as the next-hop node. In this case, if multiple DIO-1 messages are received, the path determination unit 321 determines the node that sent the DIO-1 message with the smallest rank value as the next-hop node.

[0248] ***Effects of Implementation Method 2***

[0249] As described above, the wireless communication terminal 30 in Embodiment 2 preferentially determines the node using the main protocol as the next-hop node. This reduces the possibility of grade values ​​being converted due to different protocols. Consequently, it is less likely to cause errors in grade values ​​due to conversion.

[0250] ***Other Structures***

[0251] <Variation Example 9>

[0252] Even when receiving a DIO message based on the main protocol, there may be situations where a node using another protocol is identified as the next hop node.

[0253] For example, the path determination unit 321 weights the rank values ​​calculated based on the DIO messages of the main protocol in a way that the values ​​decrease. Then, the path determination unit 321 determines the smallest rank value from all the rank values ​​calculated based on all the DIO messages, and determines the node that sent the DIO message with the smallest rank value as the next hop node. Thus, while prioritizing the determination of nodes using the main protocol as the next hop node, the possibility of determining nodes using other protocols as the next hop node is also retained.

[0254] <Variation Example 10>

[0255] In Implementation 2, the case where the first protocol is the primary protocol was described. However, the second protocol can also be the primary protocol. In this case, the node using the second protocol as the primary protocol is preferentially determined as the next-hop node.

[0256] <Variation Example 11>

[0257] In Implementation 2, nodes using the main protocol used by the collection device are preferentially determined as next-hop nodes. However, nodes using a specified protocol instead of the protocol used by the collection device may also be preferentially determined as next-hop nodes. The specified protocol may be specified in advance by the administrator of the communication system 53 or the like, or it may be specified by the collection device or other devices.

[0258] Therefore, even if the protocol used by the collection device is unknown, a specific protocol can be used preferentially.

[0259] Implementation method 3.

[0260] Implementation 3 differs from Implementations 1 and 2 in that it prioritizes sending DIO messages of the destination transfer protocol. In Implementation 3, this difference will be explained, while the similarities will be omitted.

[0261] ***Instructions for the Actions***

[0262] In implementation method 1, Figure 12 Steps S204 and S205 Figure 18 Steps S402 and S403, and Figure 18 In steps S409 and S410, the wireless communication terminal 30 broadcasts DIO-1 and DIO-2.

[0263] In implementation method 3, Figure 12 Steps S204 and S205 Figure 18 Steps S402 and S403, and Figure 18 In steps S409 and S410, the wireless communication terminal 30 preferentially sends a DIO message of the transfer destination protocol. For example, in the case of transferring the communication system 53 to a wireless mesh network centered on the wireless communication terminal 20, the second protocol used in the wireless communication terminal 20 is the transfer destination protocol.

[0264] Specifically, in Figure 12 Steps S204 and S205 Figure 18 Steps S402 and S403, and Figure 18 In steps S409 and S410, the wireless communication terminal 30 determines the DIO message to be broadcast as follows. Here, the second protocol will be used as the transfer destination protocol for explanation.

[0265] (1) When only DIO-1 is received, the wireless communication terminal 30 broadcasts and transmits only DIO-1. (2) When only DIO-2 is received, the wireless communication terminal 30 broadcasts and transmits 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 broadcasts and transmits DIO-2 and DIO-1 generated by converting DIO-2.

[0266] More specifically, it is as described below.

[0267] In case (1), the path determination unit 321 generates DIO-1, and the communication unit 311 broadcasts and transmits DIO-1.

[0268] In case (2), the path determination unit 322 generates DIO-2, and the communication unit 312 broadcasts and transmits DIO-2. In addition, the protocol conversion unit 34 converts DIO-2 into DIO-1 based on the first protocol. Then, the communication unit 311 broadcasts and transmits DIO-1.

[0269] In case (3), it is the same as in case (2). That is, the path determination unit 322 generates DIO-2, and the communication unit 312 broadcasts and transmits DIO-2. In addition, the protocol conversion unit 34 converts DIO-2 into DIO-1 based on the first protocol. Then, the communication unit 311 broadcasts and transmits DIO-1.

[0270] ***Effects of Embodiment 3***

[0271] As described above, the wireless communication terminal 30 of Embodiment 3 preferentially transmits the DIO message of the transfer destination protocol. Thereby, it is easy to promote the switching to the wireless mesh network using the transfer destination protocol.

[0272] In addition, "unit" in the above description may be replaced with "circuit", "process", "step", "processing", or "processing circuit".

[0273] As described above, the embodiments and modification examples of the present disclosure have been described. Several of these embodiments and modification examples may be implemented in combination. In addition, any one or several of them may be partially implemented. In addition, the present disclosure is not limited to the above embodiments and modification examples, and various changes can be made as needed.

[0274] Description of Reference Numerals

[0275] 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 Timing Calendar, 300 Processor, 31 Communication Unit, 311 Communication Unit, 312 Communication Unit, 32 Path Determination Unit, 321 Path Determination Unit, 322 Path Determination Unit, 33 Protocol Determination Unit, 34 Protocol Conversion Unit, 341 First-Level Conversion Table, 342 First-Level Measurement Conversion Table, 343 Second-Level Conversion Table, 344 Second-Level Measurement Conversion Table, 900 Memory, 910 Auxiliary Storage Device, 920 Input Interface, 930 Output Interface.

Claims

1. A wireless communication terminal, which constitutes a wireless mesh network. The wireless communication terminal includes: Multiple communication units, each corresponding to a different protocol; and The protocol conversion unit converts a message based on a source protocol into a message based on a destination protocol among a plurality of protocols. The source protocol is the protocol used at the sending source, which is another wireless communication terminal constituting the wireless mesh network. The destination protocol is the protocol used at the destination, which is a wireless communication terminal constituting the wireless mesh network that is different from the sending source. The communication unit corresponding to the destination protocol among the plurality of communication units sends the message converted by the protocol conversion unit. When the transmitting source is a wireless communication terminal that is the next hop when the transmitting destination is a collection device, the protocol conversion unit uses multiple protocols as the destination protocol and converts the path control message generated based on the path control message of the next hop sent from the transmitting source, which is based on the transmitting source protocol itself, into a path control message based on the destination protocol itself. The collection device is a wireless communication terminal that collects data from the wireless mesh network.

2. A wireless communication terminal, which constitutes a wireless mesh network. The wireless communication terminal includes: Multiple communication units, each corresponding to a different protocol; and The protocol conversion unit converts a message based on a source protocol into a message based on a destination protocol among a plurality of protocols. The source protocol is the protocol used at the sending source, which is another wireless communication terminal constituting the wireless mesh network. The destination protocol is the protocol used at the destination, which is a wireless communication terminal constituting the wireless mesh network that is different from the sending source. The communication unit corresponding to the destination protocol among the plurality of communication units sends the message converted by the protocol conversion unit. When the destination is a wireless communication terminal that is the next hop when the data collection device that collects data from the wireless mesh network is the destination, the protocol conversion unit converts the connection request message received from the transmission source requesting the data collection device to connect to the wireless mesh network into a connection request message based on the destination protocol.

3. The wireless communication terminal according to claim 1 or 2, wherein, The communication unit corresponding to the transmission source protocol among the plurality of communication units receives messages transmitted from the wireless communication terminal that is the transmission source.

4. The wireless communication terminal according to claim 1, wherein, The path control message includes evaluation metrics for paths in the wireless mesh network, which are protocol-related evaluation metrics. The protocol conversion unit converts the path control message based on the source protocol into a path control message based on the destination protocol by converting the evaluation index corresponding to the source protocol into the evaluation index corresponding to the destination protocol.

5. A wireless communication terminal, which constitutes a wireless mesh network. The wireless communication terminal includes: Multiple communication units, each corresponding to a different protocol; and The protocol conversion unit converts a message based on a source protocol into a message based on a destination protocol among a plurality of protocols. The source protocol is the protocol used at the sending source, which is another wireless communication terminal constituting the wireless mesh network. The destination protocol is the protocol used at the destination, which is a wireless communication terminal constituting the wireless mesh network that is different from the sending source. The communication unit corresponding to the destination protocol among the plurality of communication units sends the message converted by the protocol conversion unit. The protocol conversion unit converts the path evaluation index, calculated based on path control messages sent from surrounding wireless communication terminals and based on any of the multiple protocols, into a benchmark-form evaluation index. The wireless communication terminal further includes a path determination unit, which determines the next-hop wireless communication terminal from the surrounding wireless communication terminals based on an evaluation index in a reference form converted by the protocol conversion unit.

6. The wireless communication terminal according to claim 5, wherein, The path determination unit will preferentially determine the wireless communication terminal using the master protocol as the next-hop wireless communication terminal. The master protocol is the protocol used in the data collection device that collects data from the wireless mesh network.

7. The wireless communication terminal according to claim 1, wherein, When the protocol conversion unit receives both a path control message for the next hop based on a destination protocol among the plurality of protocols and a path control message for the next hop based on a protocol other than the destination protocol from the wireless communication terminal of the next hop, it only converts the path control message generated based on the destination protocol itself into a path control message based on the destination protocol itself.

8. The wireless communication terminal according to claim 1, wherein, The protocol conversion unit uses only the protocol used by the wireless communication terminal constituting the wireless mesh network from among the plurality of protocols as the destination protocol, and converts the message based on the sending source protocol into a message based on the destination protocol.

9. A wireless communication method for constructing a wireless mesh network, wherein, The protocol conversion unit converts a message based on a source protocol into a message based on a destination protocol among multiple protocols. The source protocol is the protocol used at the sending source, which is a wireless communication terminal constituting the wireless mesh network. The destination protocol is the protocol used at the destination, which is a wireless communication terminal constituting the wireless mesh network that is different from the sending source. The communication unit corresponding to the destination protocol among the multiple communication units corresponding to the multiple protocols sends the converted message. In the case where the sending source is a wireless communication terminal that is the next hop when the sending destination is the collection device, the protocol conversion unit uses multiple protocols as the destination protocol and converts the path control message generated based on the path control message of the next hop sent from the sending source, which is based on the sending source protocol itself, into a path control message based on the destination protocol itself, wherein the collection device is a wireless communication terminal that collects data from the wireless mesh network.

10. A wireless communication method for constructing a wireless mesh network, wherein, The protocol conversion unit converts a message based on a source protocol into a message based on a destination protocol among multiple protocols. The source protocol is the protocol used at the sending source, which is a wireless communication terminal constituting the wireless mesh network. The destination protocol is the protocol used at the destination, which is a wireless communication terminal constituting the wireless mesh network that is different from the sending source. The communication unit corresponding to the destination protocol among the multiple communication units corresponding to the multiple protocols sends the converted message. When the destination is a wireless communication terminal that is the next hop when the data collection device that collects data from the wireless mesh network is the destination, the protocol conversion unit converts the connection request message received from the transmission source requesting the data collection device to connect to the wireless mesh network into a connection request message based on the destination protocol.

11. A wireless communication method for constructing a wireless mesh network, wherein, The protocol conversion unit converts a message based on a source protocol into a message based on a destination protocol among multiple protocols. The source protocol is the protocol used at the sending source, which is a wireless communication terminal constituting the wireless mesh network. The destination protocol is the protocol used at the destination, which is a wireless communication terminal constituting the wireless mesh network that is different from the sending source. The communication unit corresponding to the destination protocol among the multiple communication units corresponding to the multiple protocols sends the converted message. The protocol conversion unit converts the path evaluation index, calculated based on path control messages sent from surrounding wireless communication terminals and based on any of the multiple protocols, into a benchmark-form evaluation index. The path determination unit determines the next-hop wireless communication terminal from the surrounding wireless communication terminals based on the evaluation indicators in the reference form.

12. A computer-readable storage medium having recorded a wireless communication program for constructing a wireless mesh network, wherein, The wireless communication program enables the computer to function as a wireless communication terminal, which performs the following processing: The protocol conversion process converts a message based on a source protocol into a message based on a destination protocol among multiple protocols. The source protocol is the protocol used at the source, which is a wireless communication terminal constituting the wireless mesh network. The destination protocol is the protocol used at the destination, which is a wireless communication terminal constituting the wireless mesh network that is different from the source. as well as The communication processing involves sending the message converted by the protocol conversion process through one of the multiple communication units corresponding to the destination protocol, from among the multiple communication units corresponding to the multiple protocols. In the protocol conversion process, when the sending source is a wireless communication terminal that is the next hop when the sending destination is the collection device, multiple protocols are used as the destination protocol respectively. The path control message generated based on the path control message of the next hop sent from the sending source and based on the sending source protocol itself is converted into a path control message based on the destination protocol itself. The collection device is a wireless communication terminal that collects data from the wireless mesh network.

13. A computer-readable storage medium having recorded a wireless communication program for constructing a wireless mesh network, wherein, The wireless communication program enables the computer to function as a wireless communication terminal, which performs the following processing: The protocol conversion process converts a message based on a source protocol into a message based on a destination protocol among multiple protocols. The source protocol is the protocol used at the source, which is a wireless communication terminal constituting the wireless mesh network. The destination protocol is the protocol used at the destination, which is a wireless communication terminal constituting the wireless mesh network that is different from the source. as well as The communication processing involves sending the message converted by the protocol conversion process through one of the multiple communication units corresponding to the destination protocol, from among the multiple communication units corresponding to the multiple protocols. In the protocol conversion process, when the destination is a wireless communication terminal that is the next hop when the data collection device that collects data from the wireless mesh network is the sending destination, the connection request message received from the sending source requesting the data collection device to connect to the wireless mesh network is converted into a connection request message based on the destination protocol.

14. A computer-readable storage medium having recorded a wireless communication program for constructing a wireless mesh network, wherein, The wireless communication program enables the computer to function as a wireless communication terminal, which performs the following processing: The protocol conversion process converts a message based on a source protocol into a message based on a destination protocol among multiple protocols. The source protocol is the protocol used at the source, which is a wireless communication terminal constituting the wireless mesh network. The destination protocol is the protocol used at the destination, which is a wireless communication terminal constituting the wireless mesh network that is different from the source. as well as The communication processing involves sending the message converted by the protocol conversion process through one of the multiple communication units corresponding to the destination protocol, from among the multiple communication units corresponding to the multiple protocols. In the protocol conversion process, the path evaluation index, calculated based on path control messages sent from surrounding wireless communication terminals and based on any of the multiple protocols, is converted into a benchmark-form evaluation index. The wireless communication terminal also performs path determination processing, in which the next-hop wireless communication terminal is determined from the surrounding wireless communication terminals based on the evaluation index in the reference form after being converted by the protocol conversion processing.

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