Subordinate unit, master unit, communication system, and communication methods.

Abstract

Invention details;

Description

Handset, base unit, communication system, communication method, and program

[0001] The present disclosure relates to a slave unit, a master unit, and a communication system.

[0002] Wireless mesh networks are used for sensor networks to collect environmental information and for electricity meter reading and collection by smart meters. In wireless mesh networks, data collection devices and client devices autonomously build a network using wireless devices. In the future, the communication methods of existing smart meters may no longer be able to cope with these issues, and next-generation smart meters with communication methods different from the current ones may be required.

[0003] As a routing protocol for wireless mesh networks, RPL (Routing Protocol for Low-Power and Lossy Networks) in Non-Patent Document 1 is defined as an Internet standard. In wireless mesh networks using RPL, there is a demand for realizing faster collection cycles and broader communication bandwidths while maintaining the data collection function of already constructed wireless mesh networks. Patent Document 1 proposes a method for selecting a communication path by converting a signal strength value for calculating a path quality value according to the wireless communication method.

[0004] Patent No. 6752383

[0005] IETF (Internet Engineering Task Force) RFC (Request for Comments): 6550 ISSN: 2070-1721 "RPL: IPv6 Routing Protocol for Low Power and Lossy Networks" March 2012 IETF Trust, T. Winter, et al. [Retrieved January 25, 2023], Internet <URL: https: / / www.rfc-editor.org / rfc / rfc6550>

[0006] The present disclosure aims to enable communication devices to select the most preferable communication method possible when communication devices that can use multiple types of communication methods and communication devices that can use only one type of communication method are mixed.

[0007] A slave device according to one aspect of the present disclosure is a slave device connected to a wireless mesh network constructed based on a first rank value calculated by a first protocol, and is characterized by comprising: a communication device that receives one or more control messages from one or more neighboring nodes, the control messages containing route information including node rank information; a protocol determination unit that determines to perform processing based on a second protocol on the rank information; an upstream route construction unit that calculates a second rank value using the rank information based on the second protocol based on the determination result of the protocol determination unit, selects one node from the one or more neighboring nodes as a parent node based on the one or more second rank values, and records the ID of the parent node and the second rank value calculated using the rank information of the parent node in a route table; and a multi-hop communication unit that creates an announcement message notifying the ID of the parent node recorded in the route table and transmits the announcement message to the master device.

[0008] In the present disclosure, the upstream route construction unit calculates a second rank value based on a second protocol so that a communication method that is more preferable than the first rank value based on the first protocol can be selected, thereby making it possible to select a preferred communication method from among multiple types of communication methods.

[0009] 1 is a configuration diagram of a communication system 501 according to a first embodiment. FIG. 1 is a configuration diagram of a first collection device 10 according to a first embodiment. FIG. 2 is a configuration diagram of a first slave device 10x according to a first embodiment. FIG. 3 is a configuration diagram of a communication system 502 according to a first embodiment. FIG. 4 is a configuration diagram of a second collection device 20 according to a first embodiment. FIG. 5 is a configuration diagram of a second slave device 20x according to a first embodiment. FIG. 6 is a configuration diagram of a third slave device 30x according to a first embodiment. FIG. 7 is a diagram showing a sequence when a first slave device 10a, a second slave device 20d, and a third slave device 30e according to a first embodiment join. FIG. 8 is a diagram showing a rank table 903 according to a first embodiment. FIG. 9 is a diagram showing an RPL rank 1 held in a route table 902 of the first slave device 10a according to a first embodiment and an ID of a selected parent node. FIG. 10 is a diagram showing a downstream route table 901 managed by the second collection device 20 according to a first embodiment. FIG. 11 is a diagram showing a wireless method bitmap and a source routing header to be added to a downstream message addressed to the first slave device 10a in the second collection device 20 according to a first embodiment. 1. A diagram showing a route table 902 held by the second slave device 20d in the first embodiment. 2. A diagram showing a downstream route table 901 managed by the second collecting device 20 in the first embodiment. 3. A diagram showing a wireless method bitmap and a source routing header to be added to a downstream message addressed to the second slave device 20d in the second collecting device 20 in the first embodiment. 4. A diagram showing a route table 902 held by the third slave device 30e in the first embodiment. 5. A diagram showing a downstream route table 901 managed by the second collecting device 20 in the first embodiment. 6. A diagram showing a wireless method bitmap and a source routing header to be added to a downstream message addressed to the third slave device 30e in the second collecting device 20 in the first embodiment. 7. A diagram showing a sequence when the second slave device 20b, the first slave device 10f, the second slave device 20g, and the third slave device 30h in the first embodiment join. 8. A diagram showing a route table 902 held by the second slave device 20b in the first embodiment. 9 is a diagram showing a downstream route table 901 managed by the second collection device 20 of embodiment 1. FIG. 10 is a diagram showing a wireless method bitmap and a source routing header to be added to a downstream message addressed to the second slave device 20b in the second collection device 20 of embodiment 1.1 is a diagram showing an RPL rank 1 and a selected parent node ID held in a route table 902 of a first slave device 10f according to the first embodiment. FIG. 2 is a diagram showing a downstream route table 901 managed by a second collecting device 20 according to the first embodiment. FIG. 3 is a diagram showing a wireless method bitmap and a source routing header to be added to a downstream message addressed to the first slave device 10f in the second collecting device 20 according to the first embodiment. FIG. 4 is a diagram showing a route table 902 held by a second slave device 20g according to the first embodiment. FIG. 5 is a diagram showing a downstream route table 901 managed by a second collecting device 20 according to the first embodiment. FIG. 6 is a diagram showing a wireless method bitmap and a source routing header to be added to a downstream message addressed to the second slave device 20g in the second collecting device 20 according to the first embodiment. FIG. 7 is a diagram showing a route table 902 held by a third slave device 30h according to the first embodiment. FIG. 8 is a diagram showing a downstream route table 901 managed by a second collecting device 20 according to the first embodiment. 1 is a diagram showing a wireless method bitmap and a source routing header to be added to a downstream message addressed to the third slave 30h in the second collecting device 20 of embodiment 1. FIG. 2 is a diagram showing a sequence when the third slave 30c and the second slave 20i of embodiment 1 join. FIG. 3 is a diagram showing a route table 902 held by the third slave 30c of embodiment 1. FIG. 4 is a diagram showing a downstream route table 901 managed by the second collecting device 20 of embodiment 1. FIG. 5 is a diagram showing a wireless method bitmap and a source routing header to be added to a downstream message addressed to the third slave 30c in the second collecting device 20 of embodiment 1. FIG. 6 is a diagram showing a route table 902 held by the second slave 20i of embodiment 1. FIG. 7 is a diagram showing a downstream route table 901 managed by the second collecting device 20 of embodiment 1. FIG. 8 is a diagram showing a wireless method bitmap and a source routing header to be added to a downstream message addressed to the second slave 20i in the second collecting device 20 of embodiment 1. 10 is a flowchart of parent node selection in the second and third slave devices according to embodiment 2. It is a diagram showing a situation in which a second slave device 20d joins a wireless mesh network configured by a second collection device 20, a first slave device 10a, a second slave device 20b, and a second slave device 20c according to embodiment 2.1 is a diagram showing a situation in which a second slave 20d joins a wireless mesh network configured by a second collection device 20, a first slave 10a, a second slave 20b, and a third slave 30c according to a second embodiment. 2 is a diagram showing a situation in which a second slave 20d joins a wireless mesh network configured by a second collection device 20, a first slave 10a, and second slaves 20b, 20c, and 20e according to a second embodiment. 3 is a diagram showing a situation in which a second slave 20d joins a wireless mesh network configured by a second collection device 20, a first slave 10a, and second slaves 20b, 20c, and 20e according to a second embodiment. 4 is a diagram showing a situation in which a second slave 20d joins a wireless mesh network configured by a second collection device 20, a first slave 10a, and third slaves 30b, 30c, and 30e according to a second embodiment. 47 is a diagram showing a situation in which a second slave 20d joins a wireless mesh network configured with a second collection device 20, a first slave 10a, and third slaves 30b, 30c, and 30e according to a second embodiment. This diagram shows a situation in which a second slave 20d joins a wireless mesh network configured with a second collection device 20, and first slaves 10a, 10b, 10c, and 10e according to a second embodiment. This diagram shows a state in which a first slave 10x has been replaced with a second slave 20x and a third slave 30x in a communication system 503 according to a third embodiment. This diagram shows a sequence for transmitting DIO-2 and DIO-1 in the second collection device 20, second slaves 20b, 20f, and 20g, and third slave 30h according to FIG. 47 of the third embodiment. This diagram is a configuration diagram of a communication system 504 according to fourth and fifth embodiments. 10 is a diagram showing a Hop-by-Hop extension header added to an upstream message by a slave device of embodiment 4. FIG. 11 is a diagram showing a wireless method bitmap and a source routing header added to a downstream message addressed to a second slave device 20b in a second collection device 20 of embodiment 4. FIG. 12 is a diagram showing a Hop-by-Hop extension header added to an upstream message by a slave device of embodiment 4. FIG. 13 is a diagram showing a wireless method bitmap and a source routing header added to a downstream message addressed to a second slave device 20r in a second collection device 20 of embodiment 4. FIG. 14 is a diagram showing a Hop-by-Hop extension header added to an upstream message by a slave device of embodiment 5.13 is a diagram showing a wireless system bitmap and a source routing header to be added to a downstream message addressed to a second slave device 20r in a second collection device 20 according to a fifth embodiment. FIG.

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, identical or corresponding parts are designated by the same reference numerals. In the description of the embodiments, the description of identical or corresponding parts will be omitted or simplified as appropriate.

[0011] ●Explanation of terms Node: Parent device and child device. Neighboring node: A node located within a communication range where radio waves can reach, and a node that has already joined the network and is capable of communication. Parent device: A radio device of the root node. Corresponds to the first collection device 10 and the second collection device 20. Child device: A radio device of a node. Corresponds to the first child device 10x, the second child device 20x, and the third child device 30x. Rank value: A value that expresses the relative position (distance) from the parent device to the child device. A route quality value that expresses the route quality from the collection device to the child device. A value that increases as the number of hops from the parent device increases on the route from the parent device to the child device. Corresponds to the RPL rank. First rank value: A rank value calculated based on the first protocol. Corresponds to RPL rank 1. In this specification, the first rank value initially set in the parent device is 128. Second rank value: A rank value calculated based on the second protocol. Corresponds to RPL rank 2. In this specification, the second rank value initially set in the parent device is 32. MinimumHopRankIncrease: The minimum increase in rank from a parent node to a child node. A value that is stored in advance in each node. MinimumHopRankIncrease-1: The first minimum increase used to calculate the first rank value. In this specification, 128 is used as the first minimum increase value for using a low transmission rate wireless system. MinimumHopRankIncrease-2: The second minimum increase value used to calculate the second rank value. In this specification, 32 is used as the second minimum increase value for using a high transmission rate wireless system. The first minimum increase value (128) is a value that is weighted four times as much as the second minimum increase value (32). Control message: A message sent from a neighboring node to invite it to join as a child node. A message that contains route information related to the construction of a route. Corresponds to DIO-1 and DIO-2. First rank information: Information of the source node for calculating the first rank value. The first rank value of the source node described in the control message and MinimumHopRankIncrease - 1. Second rank information: Information of the source node for calculating the second rank value.The second rank value of the source node described in the control message and MinimumHopRankIncrease-2. First control message: A control message including the first rank value of the source node of the control message and MinimumHopRankIncrease-1. Corresponds to DIO-1. Second control message: A control message including the second rank value of the source node of the control message and MinimumHopRankIncrease-2. Corresponds to DIO-2. Protocol: A communication protocol or algorithm for implementing the communication protocol executed by a parent or child device. First protocol: A protocol for calculating a first rank value (RPL Rank 1) using the first rank values ​​(RPL Rank 1) of neighboring nodes and selecting a parent device with the smallest first rank value (RPL Rank 1). Further, a protocol for notifying neighboring nodes of only the first rank value (RPL Rank 1). A protocol implemented by first child device 10x. Second protocol: A protocol that calculates a second rank value (RPL rank 2) using the second rank value (RPL rank 2) of a neighboring node and selects a parent device based on the second rank value (RPL rank 2). Furthermore, a protocol that selects a communication method with the parent device. Furthermore, a protocol that notifies neighboring nodes of the first rank value (RPL rank 1) calculated based on the first protocol and the second rank value (RPL rank 2) calculated based on the second protocol. A protocol implemented by the second child device 20x and the third child device 30x. Upstream path construction unit: A module that selects one node from one or more neighboring nodes as a parent node and selects a communication method with the parent node. Includes a first upstream path construction unit and a second upstream path construction unit. First upstream path construction unit: A path construction unit corresponding to the first protocol. A module that calculates the first rank value based on the first rank information of the source node. Second upstream path construction unit: A path construction unit corresponding to the second protocol. a module that calculates a second rank value based on second rank information of the source node; multi-hop communication unit: a communication unit that implements a protocol; including a first multi-hop communication unit and a second multi-hop communication unit; first multi-hop communication unit: a communication unit that implements the first protocol; second multi-hop communication unit: a communication unit that implements the second protocol;Communication method: A communication method used in the physical layer and part of the data link layer. A wireless method used between nodes. The communication method differs if the communication speed, modulation method, or transmission output method is different. First communication method: A communication method used by the first PHY 102 and the first MAC 103. Corresponds to the first PHY / MAC. A specific example is a wireless method with a low transmission rate. Second communication method: A communication method used by the second PHY 202 and the second MAC 203. Corresponds to the second PHY / MAC. A specific example is a wireless method with a high transmission rate. Node ID: An identifier that identifies a wireless device, such as a MAC address. In this specification, codes such as 10a and 10b are used as IDs.

[0012] Embodiment 1. In this embodiment 1, a communication system 501 is described in which communication devices (slave devices) installed in multiple smart meters construct a wireless mesh network using a single communication method for communication paths to a collection device (parent device). A case is also described in which, in a communication system 502, communication devices that construct the multi-hop network shown in communication system 501 are randomly replaced with new communication devices that implement a new communication method. In particular, a case is described in which a multi-hop network is constructed that takes advantage of the benefits of a new communication method while maintaining the multi-hop communication of existing communication devices.

[0013] 1 is a configuration diagram of a communication system 501 that is the premise of this disclosure. The communication system 501 is a wireless mesh network configured by connecting a first collection device 10 and multiple first slave devices 10a, 10b, ..., 10i via wireless links 601. Hereinafter, the reference numerals 10a, 10b, ..., 10i may be simply referred to as 10x. In the communication system 501, the first communication device 100 and the first slave device 10x perform multi-hop communication based only on a first protocol.

[0014] The communication system 501 includes a first collecting device 10 and a plurality of first slave devices 10x connected to the first collecting device 10 in a multi-hop manner. The communication system 501 configures a multi-hop network with the first collecting device 10 and the plurality of first slave devices 10x. The first collecting device 10 and the plurality of first slave devices 10x are wireless communication devices and are also simply referred to as nodes. A specific example of the first slave device 10x is a smart meter.

[0015] 2 is a configuration diagram of the first collection device 10. The first collection device 10 includes a first communication device 100 for communicating with the first slave device 10x, an antenna 101 for receiving wireless signals, a first PHY 102 for digitizing the wireless signals of the wireless link 601, and a first MAC 103 for performing media access control.

[0016] "PHY" refers to the physical layer in the OSI (Open Systems Interconnection) hierarchical model. "PHY" is an abbreviation for physical layer. Here, "PHY" refers to a circuit (physical layer device) for implementing the functions of the physical layer.

[0017] "MAC" is a communication protocol that forms part of the data link layer in the OSI layer model. "MAC" stands for Medium Access Control. Here, "MAC" refers to a circuit (data link layer device) that implements the functions of a communication protocol that forms part of the data link layer.

[0018] The first collecting device 10 includes a timekeeping calendar 113 for acquiring the date and time. The first collecting device 10 includes a processor 300 having a first multi-hop communication unit 301 and a first downlink route construction unit 310. The first collecting device 10 includes a memory 900 and an auxiliary storage device 922 for recording the IDs and various option settings of the slave devices present on the downlink route constructed by the first downlink route construction unit 310. The first collecting device 10 includes an input interface 930 and an output interface 940.

[0019] 3 is a configuration diagram of the first slave device 10x. The first slave device 10x has a first communication device 100 for communicating with the first collection device 10 and other first slave devices, and an antenna 101 for receiving wireless signals. The first slave device 10x has a first PHY 102 for digitizing wireless signals and a first MAC 103 for performing media access control, both in the first communication device 100. The first slave device 10x also has a sensor device 111 for sensing, an actuator device 112 for operating the slave device, and a timekeeping calendar 113 for acquiring the date and time. The first slave device 10x also has a processor 300 having a first multi-hop communication unit 301 and a first upstream path construction unit 311. The first slave device 10x includes a memory 900 for recording the next hop node to the first collection device 10 selected by the route construction and various option settings, and an auxiliary storage device 922. The first slave device 10x includes an input interface 930 and an output interface 940.

[0020] The operation of the first slave device 10x when constructing a multi-hop communication route will be described. The first multi-hop communication unit 301 transmits a DODAG Information Solicitation (DIS) message requesting construction of a multi-hop communication route at any timing. After a certain delay, the first multi-hop communication unit 301 determines whether a DODAG Information Object (DIO) message has been received from a neighboring node. When the first multi-hop communication unit 301 receives a DIO message, which is a route construction response message in response to the DIS message, from the first slave device within a certain period of time, the first multi-hop communication unit 301 passes the DIO message to the first upstream route construction unit 311.

[0021] The first upstream path construction unit 311 calculates the rank value of the first slave device 10x from the information included in the DIO message. The first upstream path construction unit 311 selects the node with the smallest calculated rank value among the neighboring nodes as the parent node, and records the parent node ID and the rank value in association with each other. The first multi-hop communication unit 301 notifies the first communication device 100 of the parent node ID. The first communication device 100 records the pair of the parent node ID and the child node.

[0022] The protocol used by the communication system 501 is referred to as a first protocol. The rank value used by the communication system 501 is referred to as a first rank value. The communication method used by the first PHY 102 and the first MAC 103 is referred to as a first communication method.

[0023] 4 is a configuration diagram of a communication system 502. The communication system 502 is a wireless mesh network configured by connecting the second collection device 20, the first slave device 10x, the second slave device 20x, and the third slave device 30x via a wireless link 601 or a wireless link 602 having a higher transmission rate than the wireless link 601. The first slave device 10x performs multi-hop communication based on a first protocol, similar to the communication system 501. The second communication device 200, the second slave device 20x, and the third slave device 30x perform multi-hop communication based on a second protocol.

[0024] 5 is a configuration diagram of the second collection device 20. The second collection device 20 has a second communication device 200 for communicating with the first slave device 10x, the second slave device 20x, and the third slave device 30x, and an antenna 201 for receiving wireless signals. The second collection device 20 has a first PHY 102 that digitizes wireless signals of a wireless link 601 and a first MAC 103 that performs media access control, in the second communication device 200. The second collection device 20 has a second PHY 202 that digitizes wireless signals of a wireless link 602 that is capable of communication at a higher transmission rate than the wireless link 601, and a second MAC 203 that performs media access control. The communication method used by the second PHY 202 and the second MAC 203 is called a second communication method. The second collecting device 20 has a processor 300 including a first multi-hop communication unit 301, a second multi-hop communication unit 302, and a second downlink path construction unit 320. The second collecting device 20 has a protocol determination unit 330 that determines whether the communication is the first multi-hop communication or the second multi-hop communication. The multi-hop communication unit 340 has the first multi-hop communication unit 301 and the second multi-hop communication unit 302. The downlink path construction unit 350 has the second downlink path construction unit 320. The second collecting device 20 implements the second protocol using the protocol determination unit 330, the multi-hop communication unit 340, and the downlink path construction unit 350.

[0025] 6 is a configuration diagram of the second slave device 20x. The second slave device 20x has a second communication device 200 for communicating with the second collection device, the first slave device 10x, the second slave device 20x, and the third slave device 30x, and an antenna 201 for receiving wireless signals. The second slave device 20x has, in the second communication device 200, a first PHY 102 that digitizes the wireless signal of the wireless link 601 and a first MAC 103 that performs media access control, and a second PHY 202 that digitizes the wireless signal of the wireless link 602 and a second MAC 203 that performs media access control. The second slave device 20x has, in the processor 300, a first multi-hop communication unit 301, a first uplink path establishment unit 311, a second multi-hop communication unit 302, and a second uplink path establishment unit 321. The second slave device 20x includes, in its processor 300, a protocol determination unit 330 that determines whether the communication is the first multihop communication or the second multihop communication, and a protocol conversion unit 370 that converts between an RPL rank value used in the first multihop communication and an RPL rank value used in the second multihop communication. The multihop communication unit 340 includes a first multihop communication unit 301 and a second multihop communication unit 302. The upstream route construction unit 360 includes a first upstream route construction unit 311, a second upstream route construction unit 321, and a protocol conversion unit 370. The second slave device 20x implements the second protocol using the protocol determination unit 330, the multihop communication unit 340, and the upstream route construction unit 360.

[0026] FIG. 7 is a configuration diagram of the third slave device 30x. The third slave device 30x differs from the second slave device of FIG. 6 in that it does not have a second PHY 202 or a second MAC 203. Therefore, the third slave device 30x cannot implement the second communication method. The processor 300 of the third slave device 30x includes a first multi-hop communication unit 301, a first uplink path construction unit 311, a second multi-hop communication unit 302, and a second uplink path construction unit 321. The third slave device 30x includes a protocol determination unit 330 that determines whether the first multi-hop communication is used or the second multi-hop communication, and a protocol conversion unit 370 that converts the RPL rank value used in the first multi-hop communication to the RPL rank value used in the second multi-hop communication. Therefore, the third slave device 30x can implement the second protocol.

[0027] The meaning of each radio is explained below. The first collection device 10 and the first slave device 10x are existing radio devices that will be replaced. The second collection device 20 and the second slave device 20x are new radio devices that have been replaced. The third slave device 30x uses the same hardware as the first slave device 10x, but has upgraded its software version to enable processing of the second protocol.

[0028] The specifications of each radio are explained below. First collection device 10 First communication method: Possible Second communication method: Not possible First protocol: Possible Second protocol: Not possible First rank value: RPL rank 1: Stored Second rank value: RPL rank 2: Not stored MinimumHopRankIncrease-1: Stored in advance MinimumHopRankIncrease-2: Not stored Control message DIO-1: Can be created Control message DIO-2: Cannot be created Announcement message DAO-1: Can be processed Announcement message DAO-2: Processed as DAO-1

[0029] Second collection device 20 First communication method: Possible Second communication method: Possible First protocol: Possible Second protocol: Possible First rank value of own node: Stored (value known to second slave device 20x and third slave device 30x) Second rank value of own node: Stored (value known to second slave device 20x and third slave device 30x) MinimumHopRankIncrease-1: Stored in advance (value known to second slave device 20x and third slave device 30x) MinimumHopRankIncrease-2: Stored in advance (value known to second slave device 20x and third slave device 30x) Control message DIO-1: Can be created Control message DIO-2: Can be created Notification message DAO-1: Can be processed Notification message DAO-2: Can be processed

[0030] First child device 10x First communication method: Possible Second communication method: Not possible First protocol: Possible Second protocol: Not possible First rank value of own node: Stored Second rank value of own node: Not stored MinimumHopRankIncrease-1: Stored in advance MinimumHopRankIncrease-2: Not stored Control message DIO-1: Can be created Control message DIO-2: Cannot be created Announcement message DAO-1: Can be created Announcement message DAO-2: Cannot be created

[0031] Second child device 20x First communication method: Possible Second communication method: Possible First protocol: Possible Second protocol: Possible First rank value of own node: Stored Second rank value of own node: Stored MinimumHopRankIncrease-1: Stored in advance MinimumHopRankIncrease-2: Stored in advance Control message DIO-1: Can be created Control message DIO-2: Can be created Announcement message DAO-1: Can be created Announcement message DAO-2: Can be created

[0032] Third child device 30x First communication method: Possible Second communication method: Not possible First protocol: Possible Second protocol: Possible First rank value of own node: Stored Second rank value of own node: Stored MinimumHopRankIncrease-1: Stored in advance MinimumHopRankIncrease-2: Stored in advance Control message DIO-1: Can be created Control message DIO-2: Can be created Announcement message DAO-1: Can be created Announcement message DAO-2: Can be processed

[0033] ● Description of Method / Program The "unit" of each unit of first multi-hop communication unit 301, first downlink path construction unit 310, first uplink path construction unit 311, second multi-hop communication unit 302, second downlink path construction unit 320, second uplink path construction unit 321, and protocol conversion unit 370 may be interpreted as "processing," "procedure," or "step." Furthermore, the "processing" of first multi-hop communication unit 301, first downlink path construction unit 310, first uplink path construction unit 311, second multi-hop communication unit 302, second downlink path construction unit 320, second uplink path construction unit 321, and protocol conversion unit 370 may be interpreted as "program," "program product," or "computer-readable recording medium on which a program is recorded." The communication program causes a computer to execute each of the processes, procedures, or steps described above, with the "unit" of each unit being interpreted as "processing," "procedure," or "step." The communication method is performed by each device in the communication system executing a communication program. The communication program may be provided by being stored on a computer-readable non-volatile recording medium. The communication program may also be provided as a program product.

[0034] The functions of first multi-hop communication unit 301, first downlink path construction unit 310, first uplink path construction unit 311, second multi-hop communication unit 302, second downlink path construction unit 320, second uplink path construction unit 321, and protocol conversion unit 370 may be realized by a single electronic circuit or may be distributed and realized by multiple electronic circuits. As another variation, some of the functions of first multi-hop communication unit 301, first downlink path construction unit 310, first uplink path construction unit 311, second multi-hop communication unit 302, second downlink path construction unit 320, second uplink path construction unit 321, and protocol conversion unit 370 may be realized by electronic circuits, and the remaining functions may be realized by software. In another variant, some or all of the functions of the first multi-hop communication unit 301, the first downlink route construction unit 310, the first uplink route construction unit 311, the second multi-hop communication unit 302, the second downlink route construction unit 320, the second uplink route construction unit 321, and the protocol conversion unit 370 may be realized by firmware.

[0035] Each of the processor and the electronic circuit is also called a processing circuitry. That is, the functions of the first multi-hop communication unit 301, the first downlink route construction unit 310, the first uplink route construction unit 311, the second multi-hop communication unit 302, the second downlink route construction unit 320, the second uplink route construction unit 321, and the protocol conversion unit 370 are realized by the processing circuitry.

[0036] Next, the operation will be described. Fig. 8 shows a sequence when the first slave device 10a, the second slave device 20d, and the third slave device 30e join the communication system 502 of Fig. 4. When the first slave device 10a joins the second collection device The operation when the first slave device 10a joins the communication system 502 will be described. The first slave device 10a creates a DIS (DODAG Information Solicitation) message (DIS-1) in the first multi-hop communication unit 301. The first communication device 100 broadcasts the DIS-1 using the first MAC 103 and the first PHY 102.

[0037] The second collection device 20, which has received DIS-1 from the first slave device 10a, describes the following route information in a DIO (DODAG Information Object) message (DIO-2) in the second multi-hop communication unit 302. The second communication device 200 responds to DIS-1 by broadcasting DIO-2 in the first MAC 103 and the first PHY 102. * RPL rank 2 of the own node * MinimumHopRankIncrease-2 used in the second multi-hop communication * Wireless method that the own node can support (wireless method using the first PHY 102 and the first MAC 103 (hereinafter referred to as the first PHY / MAC), and wireless method using the second PHY 202 and the second MAC 203 (hereinafter referred to as the second PHY / MAC)) * Device type of the own node * Number of consecutive high transmission rates from the second collection device

[0038] The second collection device 20 holds a rank table 903 as shown in Fig. 9, and writes the following route information in DIO-2 and broadcasts it: * RPL rank 2 of own node = 32 * MinimumHopRankIncrease-2 = 32 * Wireless method = second PHY / MAC * Device type = second collection device * Consecutive high transmission rates = 0

[0039] Furthermore, the second collection device 20 describes the following route information in a DIO (DODAG Information Object) message (DIO-1) in the first multi-hop communication unit 301. The second communication device 200 responds to DIS-1 by broadcasting DIO-1 in the first MAC 103 and the first PHY 102. * RPL rank 1 of the own node * MinimumHopRankIncrease-1 used in the first multi-hop communication

[0040] The second collection device 20 holds a rank table 903 as shown in FIG. 9, and writes the following path information in DIO-1 and broadcasts it: *RPLRank1=128 *MinimumHopRankIncrease-1=128

[0041] The first slave device 10a, which receives DIO-2 and DIO-1 from the second collection device 20, discards DIO-2 as an undefined message and decides to process DIO-1 in the first upstream path construction unit 311.

[0042] The first upstream route construction unit 311 of the first slave device 10a calculates the RPL rank 1 of its own node from the RPL rank 1 of the second collection device 20 described in the DIO-1, the MinimumHopRankIncrease-1 described in the DIO-1, and a metric representing the state of the wireless link between the second communication device 200 of the second collection device 20 and the first communication device 100 of the first slave device 10a, which is obtained when receiving the DIO-1.

[0043] If the metric representing the state between wireless links is 0, the first slave device 10a calculates its own node's RPL rank 1 = 256 from RPL rank 1 = 128 and MinimumHopRankIncrease-1 = 128 written in DIO-1 of the second collection device 20.

[0044] When the reception waiting time of DIO-1 times out, the first slave device 10a selects, in the first upstream route construction unit 311, the node with the smallest RPL rank 1 on the route from the second collection device 20 to the first slave device 10a as the next upstream hop (parent node) to the second collection device 20.

[0045] 10 shows the RPL rank 1 and the ID of the selected parent node stored in the routing table 902 of the first slave device 10a when the second collecting device 20 is selected as the parent node. Furthermore, the first slave device 10a creates a DAO (DODAG Advertisement Object) message (DAO-1) including the parent node ID in the first multi-hop communication unit 301. The first slave device 10a transmits the DAO-1 to the second collecting device, requests connection to the communication system 502, and completes the joining operation.

[0046] The second collection device 20 determines, via the protocol determination unit 330, that the DAO-1 received from the first slave device 10a should be processed by the first multi-hop communication unit 301 and the second downlink path construction unit 320. Since the type of wireless link (wireless method) is not described in the DAO-1, ​​the second downlink path construction unit 320 determines the wireless method to be the first PHY / MAC. The second downlink path construction unit 320 records in the downlink path table 901 the parent node ID selected by the first slave device 10a, which is described in the DAO-1, ​​and the type of wireless link (wireless method) used by the parent node selected by the first slave device 10a for the hop to the first slave device 10a.

[0047] 11 shows a downstream route table 901 managed by the second collection device 20. When transmitting a downstream message addressed to the first slave device 10a, the second collection device 20 checks the nodes to be passed from the second collection device 20 to the first slave device 10a and the designated wireless method using the downstream route table 901. In other words, the downstream message from the second collection device 20 to the first slave device 10a is transmitted to the first slave device 10a using the first PHY / MAC.

[0048] 12 shows the wireless system bitmap and source routing header added to a downstream message addressed to the first slave device 10a in the second collection device 20. The wireless system bitmap specifies the wireless system in the order of the first hop, second hop, etc., starting from the first bit using a reserved area ignored by the first slave device. The wireless system is specified by a bit value of 0 if the wireless system is the first PHY / MAC, and 1 if the wireless system is the second PHY / MAC. The source routing header lists the node IDs of the nodes through which the message will travel to its destination in hop order. When the first slave device 10a receives a downstream message containing the wireless system bitmap and source routing header, it ignores the wireless system bitmap and refers only to the source routing header to transfer or receive the message.

[0049] When the second handset 20d joins via the first handset 10a, the operation of the second handset 20d joining the communication system 502 will be described. The second handset 20d creates a DIS (DODAG Information Solicitation) message (DIS-1) in the first multi-hop communication unit 301. The second communication device 200 broadcasts the DIS-1 via the first MAC 103 and the first PHY 102.

[0050] The first slave device 10a, which has received DIS-1 from the second slave device 20d, writes the following route information in a DIO (DODAG Information Object) message (DIO-1) in the first multi-hop communication unit 301. The first communication device 100 responds to DIS-1 by broadcasting DIO-1 in the first MAC 103 and the first PHY 102. * RPL rank of the own node: 1 * MinimumHopRankIncrease-1 used in the first multi-hop communication

[0051] The first slave device 10a holds a route table 902 as shown in FIG. 10, and writes the following route information in DIO-1 and broadcasts it: *RPL rank 1=256 *MinimumHopRankIncrease-1=128

[0052] The second slave device 20d, which has received DIO-1 from the first slave device 10a, determines in the protocol determination unit 330 that the DIO-1 should be processed by the first upstream path establishment unit 311. The first upstream path establishment unit 311 of the second slave device 20d calculates the RPL rank 1 of its own node from the following information: *RPL rank 1 of the first slave device 10a described in the DIO-1 *Metric indicating the state of the wireless link between the first communication device 100 of the first slave device 10a and the second communication device 200 of the second slave device 20d, acquired when receiving the DIO-1 *MinimumHopRankIncrease-1 described in the DIO-1

[0053] If the metric representing the state between the wireless links is 0, the second slave device 20d calculates its own node's RPL rank 1 = 384 from RPL rank 1 = 256 and MinimumHopRankIncrease-1 = 128 written in DIO-1 of the first slave device 10a.

[0054] Furthermore, the second slave device 20d calculates an RPL rank 2 from the information described in DIO-1, MinimumHopRankIncrease-2=32 stored in advance as a parameter, and a metric indicating the state between the wireless links, using the protocol conversion unit 370. The protocol conversion unit 370 transmits the RPL rank 2 to the second upstream path construction unit 321.

[0055] The operation of the protocol conversion unit 370 is as follows. It is assumed that the communication system 502 employs LQL (Link Quality Level) as a metric representing the state between wireless links. The number of hops from the second collection device 20 to the second slave device 20d is calculated using the information written in the LQL. It is assumed that all hops "use the first MAC 103 and the first PHY 102, which have a lower transmission rate than the second MAC 203 and the second PHY 202, via the first slave device." A weighting factor for the low transmission rate is applied to all hops, and RPL rank 2 = 160 is calculated as follows: RPL rank 2 = (RPL rank 2 of the second collection device 20 (= 32) + MinimumHopRankIncrease - 2 (= 32) × number of hops (2) × weighting factor for the low transmission rate (= 2) + metric (= 0)) = 160

[0056] When the DIO reception waiting time times out, the second slave device 20d selects, in the second upstream route construction unit 321, the node with the smallest RPL rank 2 on the route from the second collection device 20 to the second slave device 20d as the next upstream hop (parent node) to the second collection device 20.

[0057] 13 shows a route table 902 held by the second slave device 20d when the first slave device 10a is selected as the parent node. The second slave device 20d manages the RPL rank 1, RPL rank 2, the ID of the parent node selected based on the RPL rank 2, the type of the parent node, the wireless system with the parent node, the number of consecutive high transmission rate links (the second PHY 202 and the second MAC 203) from the second collection device 20, the presence or absence of a third slave device on the route, and the presence or absence of a first slave device on the route.

[0058] The route table 902 of the second child device 20d is as follows: *RPL rank 1 = 384 *RPL rank 2 = 160 *Parent node ID = 10a *Type of parent node = first child device *Wireless method with parent node = first PHY / MAC *Continuous high transmission rate = 0 (details unknown as the parent node is the first child device, but default is set to 0) *Presence or absence of third child device = No (details unknown as the parent node is the first child device, but default is set to No) *Presence or absence of first child device = Yes (parent node is the first child device)

[0059] Furthermore, the second slave device 20d creates a DAO (DODAG Advertisement Object) message (DAO-2) including the parent node ID, the node type of the node itself, and the wireless method with the parent node in the second multi-hop communication unit 302. The second slave device 20d transmits the DAO-2 to the second collection device 20 via the first slave device 10a selected as the parent node, requests connection to the communication system 502, and completes the joining operation.

[0060] The second collection device 20 determines by the protocol determination unit 330 that DAO-2 received from the second slave device 20d should be processed by the second multi-hop communication unit 302 and the second downlink path construction unit 320. The second downlink path construction unit 320 records the parent node ID selected by the second slave device 20d, which is written in DAO-2, and the wireless method with the parent node in the downlink path table 901.

[0061] 14 shows a downstream route table 901 managed by the second collection device 20. When transmitting a downstream message addressed to the second slave device 20d, the second collection device 20 checks the nodes to be passed from the second collection device 20 to the second slave device 20d and the designated wireless method by tracing the downstream route table 901. In other words, the downstream message from the second collection device 20 to the second slave device 20d is transmitted using the first PHY / MAC to the first slave device 10a and the second PHY / MAC to the second slave device 20d.

[0062] 15 shows the wireless system bitmap and source routing header added to a downstream message addressed to the second slave device 20d in the second collection device 20. The wireless system bitmap specifies the wireless system in the order of the first hop, second hop, etc., from the first bit using a reserved area ignored by the first slave device. The wireless system is specified by a bit value of 0 if the wireless system is the first PHY / MAC, and 1 if the wireless system is the second PHY / MAC. The source routing header lists the node IDs of the nodes through which the message will be routed to its destination in hop order. When the first slave device 10a receives a downstream message containing the wireless system bitmap and source routing header, it references the wireless system bitmap and source routing header and transfers the message to the second slave device 20d using the first PHY / MAC.

[0063] When the third handset 30e joins via the first handset 10a, the operation of the third handset 30e joining the communication system 502 will be described. The third handset 30e creates a DIS (DODAG Information Solicitation) message (DIS-1) in the first multi-hop communication unit 301. The first communication device 100 broadcasts the DIS-1 via the first MAC 103 and the first PHY 102.

[0064] The first slave device 10a, which has received the DIS-1 from the third slave device 30e, writes the following route information in a DIO (DODAG Information Object) message (DIO-1) in the first multi-hop communication unit 301. The first communication device 100 responds to the DIS-1 by broadcasting the DIO-1 in the first MAC 103 and the first PHY 102. * RPL rank of the own node: 1 * MinimumHopRankIncrease-1 used in the first multi-hop communication

[0065] The first slave device 10a holds a route table 902 as shown in FIG. 10, and writes the following route information in DIO-1 and broadcasts it: *RPL rank 1=256 *MinimumHopRankIncrease-1=128

[0066] The third slave 30e, which has received DIO-1 from the first slave 10a, determines in the protocol determination unit 330 that the DIO-1 should be processed by the first upstream path establishment unit 311. The first upstream path establishment unit 311 of the third slave 30e calculates the RPL rank 1 of its own node from the following information: *RPL rank 1 of the first slave 10a described in the DIO-1 *Metric indicating the state of the wireless link between the first communication device 100 of the first slave 10a and the first communication device 100 of the third slave 30e, acquired when receiving the DIO-1 *MinimumHopRankIncrease-1 described in the DIO-1

[0067] If the metric representing the state between the wireless links is 0, the third slave device 30e calculates its own node's RPL rank 1 = 384 from RPL rank 1 = 256 and MinimumHopRankIncrease-1 = 128 written in DIO-1 of the first slave device 10a.

[0068] Furthermore, the third slave device 30e calculates an RPL rank 2 from the information described in DIO-1, MinimumHopRankIncrease-2=32 stored in advance as a parameter, and a metric indicating the state between the wireless links, using the protocol conversion unit 370. The protocol conversion unit 370 transmits the RPL rank 2 to the second upstream path construction unit 321.

[0069] The operation of the protocol conversion unit 370 is as follows. It is assumed that the communication system 502 employs LQL (Link Quality Level) as a metric representing the state between wireless links. The number of hops from the second collection device 20 to the third slave device 30e is calculated using the information written in the LQL. It is assumed that all hops "passed through the first slave device and used the first MAC 103 and first PHY 102, which have a lower transmission rate than the second MAC 203 and second PHY 202." A weighting factor for the low transmission rate is applied to all hops, and RPL rank 2 = 160 is calculated as follows: RPL rank 2 = (RPL rank 2 of the second collection device 20 (= 32) + MinimumHopRankIncrease - 2 (= 32) × number of hops (2) × weighting factor for the low transmission rate (= 2) + metric (= 0)) = 160

[0070] When the DIO reception waiting time times out, the third slave device 30e selects, in the second upstream route construction unit 321, the node with the smallest RPL rank 2 on the route from the second collection device 20 to the third slave device 30e as the next upstream hop (parent node) to the second collection device 20.

[0071] 16 shows a route table 902 held by the third slave device 30e when the first slave device 10a is selected as the parent node. The third slave device 30e manages the RPL rank 1, RPL rank 2, the ID of the parent node selected based on the RPL rank 2, the type of the parent node, the wireless system with the parent node, the number of consecutive high transmission rate links (the second PHY 202 and the second MAC 203) from the second collection device 20, the presence or absence of a third slave device on the route, and the presence or absence of a first slave device on the route.

[0072] The route table 902 of the third child device 30e is as follows: *RPL rank 1 = 384 *RPL rank 2 = 160 *Parent node ID = 10a *Type of parent node = first child device *Wireless method with parent node = first PHY / MAC *Continuous high transmission rate = 0 (details unknown as the parent node is the first child device, but default is set to 0) *Presence or absence of third child device = No (details unknown as the parent node is the first child device, but default is set to No) *Presence or absence of first child device = Yes (parent node is the first child device)

[0073] Furthermore, the third slave device 30e creates a DAO (DODAG Advertisement Object) message (DAO-2) including the parent node ID, the node type of the own node, and the wireless method with the parent node in the second multi-hop communication unit 302. The third slave device 30e transmits the DAO-2 to the second collection device 20 via the first slave device 10a that selected the DAO-2 as its parent node, requests connection to the communication system 502, and completes the joining operation.

[0074] The second collection device 20 determines by the protocol determination unit 330 that DAO-2 received from the third slave device 30e should be processed by the second multi-hop communication unit 302 and the second downlink path construction unit 320. The second downlink path construction unit 320 records the parent node ID selected by the third slave device 30e, which is written in DAO-2, and the wireless method with the parent node in the downlink path table 901.

[0075] 17 shows a downstream route table 901 managed by the second collection device 20. When transmitting a downstream message addressed to the third slave device 30e, the second collection device 20 checks the nodes to be passed from the second collection device 20 to the third slave device 30e and the designated wireless method by tracing the downstream route table 901. In other words, the downstream message from the second collection device 20 to the third slave device 30e is transmitted using the first PHY / MAC to the first slave device 10a and the second PHY / MAC to the third slave device 30e.

[0076] 18 shows the wireless method bitmap and source routing header added to a downstream message addressed to the third slave device 30e in the second collection device 20. The wireless method bitmap specifies the wireless method in the order of the first hop, second hop, etc., starting from the first bit using a reserved area ignored by the first slave device. The wireless method is specified by a bit value of 0 if the wireless method is the first PHY / MAC, and 1 if the wireless method is the second PHY / MAC. The source routing header lists the node IDs of the nodes through which the message will be routed to its destination in hop order.

[0077] When the first slave device 10a receives a downstream message containing the wireless system bitmap and source routing header, it ignores the wireless system bitmap, refers only to the source routing header, and transfers the message to the third slave device 30e using the first PHY / MAC.

[0078] 19 shows a sequence when the second slave device 20b, the first slave device 10f, the second slave device 20g, and the third slave device 30h join the communication system 502 of FIG. 4. When the second slave device 20b joins the second collection device 20 The operation of the second slave device 20b joining the communication system 502 will be described. The second slave device 20b creates a DIS (DODAG Information Solicitation) message (DIS-1) in the first multi-hop communication unit 301. The second communication device 200 broadcasts the DIS-1 using the first MAC 103 and the first PHY 102.

[0079] The second collection device 20, which has received DIS-1 from the second slave device 20b, writes the following route information in a DIO (DODAG Information Object) message (DIO-2) in the second multi-hop communication unit 302. The second communication device 200 responds to DIS-1 by broadcasting DIO-2 using the first MAC 103 and the first PHY 102. * RPL rank 2 of the own node * MinimumHopRankIncrease-2 used in the second multi-hop communication * Wireless method compatible with the own node (first PHY 102 and first MAC 103 and second PHY 202 and second MAC 203) * Device type of the own node * Number of consecutive high transmission rates from the second collection device

[0080] The second collection device 20 holds a rank table 903 as shown in FIG. 9, and writes the following route information in DIO-2 and broadcasts it: *RPL rank 2 = 32 *MinimumHopRankIncrease-2 = 32 *Wireless system = second PHY / MAC *Device type = second collection device *Continuous high transmission rate = 0

[0081] Furthermore, the second collection device 20 describes the following route information in a DIO (DODAG Information Object) message (DIO-1) in the first multi-hop communication unit 301. The second communication device 200 responds to DIS-1 by broadcasting DIO-1 in the first MAC 103 and the first PHY 102. * RPL rank 1 of the own node * MinimumHopRankIncrease-1 used in the first multi-hop communication

[0082] The second collection device 20 holds a rank table 903 as shown in FIG. 9, and writes the following path information in DIO-1 and broadcasts it: *RPLRank1=128 *MinimumHopRankIncrease-1=128

[0083] The second slave device 20b, which receives DIO-2 and DIO-1 from the second collection device 20, determines using the protocol determination unit 330 to process DIO-2 in the second multi-hop communication unit 302 and the second upstream path construction unit 321, and to process DIO-1 in the first multi-hop communication unit 301 and the first upstream path construction unit 311.

[0084] The second upstream path construction unit 321 of the second slave device 20b calculates the RPL rank 2 of its own node from the RPL rank 2 of the second collection device 20 described in the DIO-2, the MinimumHopRankIncrease-2 described in the DIO-2, and a metric representing the state of the wireless link between the second communication device 200 of the second collection device 20 and the second communication device 200 of the second slave device 20b, which is obtained when receiving the DIO-2.

[0085] The second slave device 20b calculates RPL rank 2=64 from the information written in DIO-2 of the second collecting device 20 and the metric of the wireless link as follows: RPL rank 2=(RPL rank 2 of the second collecting device 20 (=32)+MinimumHopRankIncrease-2 (=32)+Metric (=0))=64

[0086] The first upstream route construction unit 311 of the second slave device 20b calculates the RPL rank 1 of its own node from the RPL rank 1 of the second collection device 20 described in the DIO-1, the MinimumHopRankIncrease-1 described in the DIO-1, and a metric representing the state of the wireless link between the second communication device 200 of the second collection device 20 and the second communication device 200 of the second slave device 20b, which is obtained when receiving the DIO-1.

[0087] If the metric representing the state between the wireless links is 0, the second slave device 20b calculates its own node's RPL rank 1 = 256 from RPL rank 1 = 128 and MinimumHopRankIncrease-1 = 128 written in DIO-1 of the second collection device 20.

[0088] The second slave device 20b may be unable to receive DIO-1 due to a communication failure. If the second slave device 20b can only receive DIO-2, the protocol conversion unit 370 calculates the number of hops from the information contained in DIO-2 and calculates an RPL rank of 1.

[0089] The operation of the protocol conversion unit 370 is as follows. It is assumed that the communication system 502 employs LQL (Link Quality Level) as a metric representing the state between wireless links. The number of hops from the second collection device 20 to the second slave device 20b is calculated using the information written in the LQL. Assuming that all hops "use the first MAC 103 and first PHY 102 with a low transmission rate," RPL rank 1 = 256 is calculated as follows: RPL rank 1 = (RPL rank 1 of the second collection device 20 (= 128) + MinimumHopRankIncrease - 1 (= 128) × number of hops (1) + metric (= 0)) = 256

[0090] When the DIO reception waiting time times out, the second slave device 20b selects, in the second upstream route construction unit 321, the node with the smallest RPL rank 2 on the route from the second collection device 20 to the second slave device 20b as the next upstream hop (parent node) to the second collection device 20.

[0091] 20 shows a route table 902 held by the second slave device 20b when the second collection device 20 is selected as a parent node. The second slave device 20b manages the RPL rank 1, RPL rank 2, the ID of the parent node selected based on the RPL rank 2, the type of the parent node, the wireless system with the parent node, the number of consecutive high transmission rate links (second PHY 202 and second MAC 203) from the second collection device 20, the presence or absence of a third slave device on the route, and the presence or absence of a first slave device on the route.

[0092] The route table 902 of the second slave device 20b is as follows: *RPL rank 1=256 *RPL rank 2=64 *Parent node ID=20 *Type of parent node=second collection device *Wireless system with parent node=second PHY / MAC *Continuous high transmission rate=1 *Presence or absence of third slave device=No *Presence or absence of first slave device=No

[0093] Furthermore, the second slave device 20b creates a DAO (DODAG Advertisement Object) message (DAO-2) including the parent node ID, the node type of the own node, and the wireless system with the parent node in the second multi-hop communication unit 302. The second slave device 20b transmits the DAO-2 to the second collecting device 20, requests connection to the communication system 502, and completes the joining operation.

[0094] The second collection device 20 determines by the protocol determination unit 330 that DAO-2 received from the second slave device 20b should be processed by the second multi-hop communication unit 302 and the second downlink path construction unit 320. The second downlink path construction unit 320 records the parent node ID selected by the second slave device 20b, which is written in DAO-2, and the wireless method with the parent node in the downlink path table 901.

[0095] 21 shows a downstream route table 901 managed by the second collection device 20. When the second collection device 20 transmits a downstream message addressed to the second slave device 20b, the second collection device 20 checks the nodes to be passed from the second collection device 20 to the second slave device 20b and the designated wireless method by tracing the downstream route table 901. In other words, the downstream message from the second collection device 20 to the second slave device 20b is transmitted to the second slave device 20b using the second PHY / MAC.

[0096] 22 shows the wireless method bitmap and source routing header added to a downstream message addressed to the second slave device 20b in the second collection device 20. The wireless method bitmap specifies the wireless method in the order of the first hop, second hop, etc., from the top bit using a reserved area ignored by the first slave device. The wireless method is specified by a bit value of 0 if the wireless method is the first PHY / MAC, and 1 if the wireless method is the second PHY / MAC. The source routing header lists the node IDs of the nodes through which the message will be routed to its destination in hop order.

[0097] When the second slave unit 20b receives the downstream message containing the wireless system bitmap and source routing header, it references the wireless system bitmap and source routing header and determines that the message is addressed to its own node.

[0098] When the first slave device 10f joins via the second slave device 20b, the operation of the first slave device 10f joining the communication system 502 will be described. The first slave device 10f creates a DIS (DODAG Information Solicitation) message (DIS-1) in the first multi-hop communication unit 301. The first communication device 100 broadcasts the DIS-1 via the first MAC 103 and the first PHY 102.

[0099] The second slave device 20b, which has received DIS-1 from the first slave device 10f, writes the following route information in a DIO (DODAG Information Object) message (DIO-2) in the second multi-hop communication unit 302. The second communication device 200 responds to DIS-1 by broadcasting DIO-2 using the first MAC 103 and the first PHY 102. * RPL rank 2 of the own node * MinimumHopRankIncrease-2 used in the second multi-hop communication * Wireless method compatible with the own node (first PHY 102 and first MAC 103 and second PHY 202 and second MAC 203) * Device type of the own node * Number of consecutive high transmission rates from the second collection device

[0100] The second handset 20b holds a route table 902 as shown in FIG. 20, and writes the following route information in DIO-2 and broadcasts it: *RPL rank 2 = 64 *MinimumHopRankIncrease-2 = 32 *Wireless system = second PHY / MAC *Device type = second handset *Continuous high transmission rate = 1

[0101] Furthermore, the second slave device 20b writes the following route information in a DIO (DODAG Information Object) message (DIO-1) in the first multi-hop communication unit 301. The second communication device 200 responds to DIS-1 by broadcasting DIO-1 in the first MAC 103 and the first PHY 102. * RPL rank of the own node: 1 * MinimumHopRankIncrease-1 used in the first multi-hop communication

[0102] The second slave device 20b holds a route table 902 as shown in FIG. 20, and writes the following route information in DIO-1 and broadcasts it: *RPL rank 1=256 *MinimumHopRankIncrease-1=128

[0103] The first slave device 10f, which receives DIO-2 and DIO-1 from the second slave device 20b, discards DIO-2 as an undefined message and decides to process DIO-1 in the first upstream path construction unit 311.

[0104] The first upstream path construction unit 311 of the first slave device 10f calculates the RPL rank 1 of its own node from the RPL rank 1 of the second slave device 20b described in the DIO-1, the MinimumHopRankIncrease-1 described in the DIO-1, and a metric representing the state of the wireless link between the second communication device 200 of the second slave device 20b and the first communication device 100 of the first slave device 10f, which is obtained when receiving the DIO-1.

[0105] If the metric representing the state between the wireless links is 0, the first slave device 10f calculates its own node's RPL rank 1 = 384 from RPL rank 1 = 256 and MinimumHopRankIncrease-1 = 128 written in DIO-1 of the second slave device 20b.

[0106] When the reception waiting time of DIO-1 times out, the first slave device 10f selects, in the first upstream route construction unit 311, the node with the smallest RPL rank 1 on the route from the second collection device 20 to the first slave device 10f as the next upstream hop (parent node) to the second collection device 20.

[0107] 23 shows the RPL rank 1 and the ID of the selected parent node stored in the routing table 902 of the first slave device 10f when the second slave device 20b is selected as the parent node. Furthermore, the first slave device 10a creates a DAO (DODAG Advertisement Object) message (DAO-1) including the parent node ID in the first multi-hop communication unit 301. The first slave device 10f transmits the DAO-1 to the second collection device, requests connection to the communication system 502, and completes the joining operation.

[0108] The second collection device 20 determines, via the protocol determination unit 330, that DAO-1 received from the first slave device 10f should be processed by the first multi-hop communication unit 301 and the second downlink path construction unit 320. Since the type of wireless link (wireless method) is not described in DAO-1, ​​the second downlink path construction unit 320 determines the wireless method to be the first PHY / MAC. The second downlink path construction unit 320 records in the downlink path table 901 the parent node ID selected by the first slave device 10f, which is described in DAO-1, ​​and the type of wireless link (wireless method) used by the parent node for the hop to the first slave device 10f.

[0109] 24 shows a downstream route table 901 managed by the second collection device 20. When transmitting a downstream message addressed to the first slave device 10f, the second collection device 20 checks the nodes to be passed from the second collection device 20 to the first slave device 10f and the designated wireless method using the downstream route table 901. In other words, the downstream message from the second collection device 20 to the first slave device 10f is transmitted using the second PHY / MAC to the second slave device 20b and the first PHY / MAC to the first slave device 10f.

[0110] 25 shows the wireless method bitmap and source routing header added to a downstream message addressed to the first slave device 10f in the second collection device 20. The wireless method bitmap specifies the wireless method in the order of the first hop, second hop, etc., starting from the first bit using a reserved area ignored by the first slave device. The wireless method is specified by a bit value of 0 if the wireless method is the first PHY / MAC, or 1 if the wireless method is the second PHY / MAC. The source routing header lists the node IDs of the nodes through which the message will be routed to its destination in hop order.

[0111] When the second handset 20b receives a downstream message containing the wireless system bitmap and source routing header, it references the wireless system bitmap and source routing header and forwards the message to the first handset 10f using the first PHY / MAC.

[0112] When the second handset 20g joins via the second handset 20b, the operation of the second handset 20g joining the communication system 502 will be described. The second handset 20g creates a DIS (DODAG Information Solicitation) message (DIS-1) in the first multi-hop communication unit 301. The second communication device 200 broadcasts the DIS-1 via the first MAC 103 and the first PHY 102.

[0113] The second slave device 20b, which has received DIS-1 from the second slave device 20g, describes the following route information in a DIO (DODAG Information Object) message (DIO-2) in the second multi-hop communication unit 302. The second communication device 200 responds to DIS-1 by broadcasting DIO-2 using the first MAC 103 and the first PHY 102. * RPL rank 2 of the own node * MinimumHopRankIncrease-2 used in the second multi-hop communication * Wireless method compatible with the own node (first PHY 102 and first MAC 103 and second PHY 202 and second MAC 203) * Device type of the own node * Number of consecutive high transmission rates from the second collection device

[0114] The second handset 20b holds a route table 902 as shown in FIG. 20, and writes the following route information in DIO-2 and broadcasts it: *RPL rank 2 = 64 *MinimumHopRankIncrease-2 = 32 *Wireless system = second PHY / MAC *Device type = second handset *Continuous high transmission rate = 1

[0115] Furthermore, the second slave device 20b writes the following route information in a DIO (DODAG Information Object) message (DIO-1) in the first multi-hop communication unit 301. The second communication device 200 responds to DIS-1 by broadcasting DIO-1 in the first MAC 103 and the first PHY 102. * RPL rank of the own node: 1 * MinimumHopRankIncrease-1 used in the first multi-hop communication

[0116] The second slave device 20b holds a route table 902 as shown in FIG. 20, and writes the following route information in DIO-1 and broadcasts it: *RPL rank 1=256 *MinimumHopRankIncrease-1=128

[0117] The second slave device 20g, which receives DIO-2 and DIO-1 from the second slave device 20b, determines using the protocol determination unit 330 to process DIO-2 in the second multi-hop communication unit 302 and the second upstream path construction unit 321, and to process DIO-1 in the first multi-hop communication unit 301 and the first upstream path construction unit 311.

[0118] The second upstream path construction unit 321 of the second slave device 20g calculates the RPL rank 2 of its own node from the RPL rank 2 of the second slave device 20b described in the DIO-2, the MinimumHopRankIncrease-2 described in the DIO-2, and a metric representing the state of the wireless link between the second communication device 200 of the second slave device 20b and the second communication device 200 of the second slave device 20g, which is obtained when receiving the DIO-2.

[0119] The second terminal 20g calculates RPL rank 2=96 from the information written in DIO-2 of the second terminal 20b and the metric of the wireless link as follows: RPL rank 2=(RPL rank 2 of the second terminal 20b (=64) + MinimumHopRankIncrease-2 (=32) + metric (=0))=96

[0120] The first upstream route construction unit 311 of the second slave device 20g calculates the RPL rank 1 of its own node from the RPL rank 1 of the second slave device 20b described in the DIO-1, the MinimumHopRankIncrease-1 described in the DIO-1, and a metric representing the state of the wireless link between the second communication device 200 of the second slave device 20b and the second communication device 200 of the second slave device 20g, which is obtained when receiving the DIO-1.

[0121] If the metric representing the state between the wireless links is 0, the second slave device 20g calculates its own node's RPL rank 1 = 384 from RPL rank 1 = 256 and MinimumHopRankIncrease-1 = 128 written in DIO-1 of the second slave device 20b.

[0122] When the DIO reception waiting time times out, the second slave device 20g selects, in the second upstream route construction unit 321, the node with the smallest RPL rank 2 on the route from the second collection device 20 to the second slave device 20g as the next upstream hop (parent node) to the second collection device 20.

[0123] 26 shows a route table 902 held by the second slave device 20g when the second slave device 20b is selected as the parent node. The second slave device 20g manages the RPL rank 1, RPL rank 2, the ID of the parent node selected based on the RPL rank 2, the type of the parent node, the wireless system with the parent node, the number of consecutive high transmission rate links (the second PHY 202 and the second MAC 203) from the second collection device 20, the presence or absence of a third slave device on the route, and the presence or absence of a first slave device on the route.

[0124] The route table 902 of the second slave device 20g is as follows: *RPL rank 1 = 384 *RPL rank 2 = 96 *Parent node ID = 20b *Type of parent node = second slave device *Wireless system with parent node = second PHY / MAC *Continuous high transmission rate = 2 *Whether or not there is a third slave device = No *Whether or not there is a first slave device = No

[0125] Furthermore, the second slave device 20g creates a DAO (DODAG Advertisement Object) message (DAO-2) including the parent node ID, the node type of the own node, and the wireless system with the parent node in the second multi-hop communication unit 302. The second slave device 20g transmits the DAO-2 to the second collecting device 20, requests connection to the communication system 502, and completes the joining operation.

[0126] The second collection device 20 determines by the protocol determination unit 330 that DAO-2 received from the second slave device 20g should be processed by the second multi-hop communication unit 302 and the second downlink path construction unit 320. The second downlink path construction unit 320 records the parent node ID selected by the second slave device 20g, which is written in DAO-2, and the wireless method with the parent node in the downlink path table 901.

[0127] 27 shows a downstream route table 901 managed by the second collection device 20. When transmitting a downstream message addressed to the second slave device 20g, the second collection device 20 checks the nodes to be passed from the second collection device 20 to the second slave device 20g and the designated wireless method by tracing the downstream route table 901. In other words, the downstream message from the second collection device 20 to the second slave device 20g is transmitted using the second PHY / MAC to the second slave device 20b and the second PHY / MAC to the second slave device 20g.

[0128] 28 shows the wireless method bitmap and source routing header added to a downstream message addressed to the second slave device 20g in the second collection device 20. The wireless method bitmap specifies the wireless method in the order of the first hop, second hop, etc., from the top bit using a reserved area ignored by the first slave device. The wireless method is specified by a bit value of 0 if the wireless method is the first PHY / MAC, and 1 if the wireless method is the second PHY / MAC. The source routing header lists the node IDs of the nodes through which the message will be routed to its destination in hop order.

[0129] When the second handset 20b receives the downstream message containing the wireless system bitmap and source routing header, it references the wireless system bitmap and source routing header and transfers the message to the second handset 20g using the second PHY / MAC.

[0130] The third handset 30h joins via the second handset 20b. The operation of the third handset 30h joining the communication system 502 will be described. The third handset 30h creates a DIS (DODAG Information Solicitation) message (DIS-1) in the first multi-hop communication unit 301. The second communication device 200 broadcasts the DIS-1 via the first MAC 103 and the first PHY 102.

[0131] The second slave device 20b, which has received DIS-1 from the third slave device 30h, writes the following route information in a DIO (DODAG Information Object) message (DIO-2) in the second multi-hop communication unit 302. The second communication device 200 responds to DIS-1 by broadcasting DIO-2 using the first MAC 103 and the first PHY 102. * RPL rank 2 of the own node * MinimumHopRankIncrease-2 used in the second multi-hop communication * Wireless method compatible with the own node (first PHY 102 and first MAC 103 and second PHY 202 and second MAC 203) * Device type of the own node * Number of consecutive high transmission rates from the second collection device

[0132] The second handset 20b holds a route table 902 as shown in FIG. 20, and writes the following route information in DIO-2 and broadcasts it: *RPL rank 2 = 64 *MinimumHopRankIncrease-2 = 32 *Wireless system = second PHY / MAC *Device type = second handset *Continuous high transmission rate = 1

[0133] Furthermore, the second slave device 20b writes the following route information in a DIO (DODAG Information Object) message (DIO-1) in the first multi-hop communication unit 301. The second slave device 20b responds to DIS-1 by broadcasting DIO-1 in the first MAC 103 and first PHY 102 of the second communication device 200. * RPL rank 1 of the own node * MinimumHopRankIncrease-1 used in the first multi-hop communication

[0134] The second slave device 20b holds a route table 902 as shown in FIG. 20, and writes the following route information in DIO-1 and broadcasts it: *RPL rank 1=256 *MinimumHopRankIncrease-1=128

[0135] The third slave device 30h, which receives DIO-2 and DIO-1 from the second slave device 20b, determines using its protocol determination unit 330 that DIO-2 should be processed by the second multi-hop communication unit 302 and the second upstream path construction unit 321, and that DIO-1 should be processed by the first multi-hop communication unit 301 and the first upstream path construction unit 311.

[0136] The second upstream path construction unit 321 of the third slave device 30h calculates the RPL rank 2 of its own node from the RPL rank 2 of the second slave device 20b described in the DIO-2, the MinimumHopRankIncrease-2 described in the DIO-2, a metric representing the state of the wireless link between the second communication device 200 of the second slave device 20b and the first communication device 100 of the third slave device 30h, which is obtained when receiving the DIO-2, and a weighting of the use of the first MAC 103 and the first PHY 102, which have a lower transmission rate than the second MAC 203 and the second PHY 202.

[0137] The third handset 30h calculates RPL rank 2=128 from the information recorded in DIO-2 of the second handset 20b and the wireless link metric as follows: RPL rank 2=(RPL rank 2 of the second handset 20b (=64) + MinimumHopRankIncrease-2 (=32) x Low transmission rate weight (=2) + Metric (=0))=96

[0138] The first upstream route construction unit 311 of the third slave device 30h calculates the RPL rank 1 of its own node from the RPL rank 1 of the second slave device 20b described in the DIO-1, the MinimumHopRankIncrease-1 described in the DIO-1, and a metric representing the state of the wireless link between the second communication device 200 of the second slave device 20b and the first communication device 100 of the third slave device 30h, which is obtained when receiving the DIO-1.

[0139] If the metric representing the state between the wireless links is 0, the third slave device 30h calculates its own node's RPL rank 1 = 384 from RPL rank 1 = 256 and MinimumHopRankIncrease-1 = 128 written in DIO-1 of the second slave device 20b.

[0140] The third slave device 30h may be unable to receive DIO-1 due to a communication failure. If the third slave device 30h can only receive DIO-2, the protocol conversion unit 370 calculates the number of hops from the information written in DIO-2 and calculates an RPL rank of 1.

[0141] The operation of the protocol conversion unit 370 is as follows. It is assumed that the communication system 502 employs LQL (Link Quality Level) as a metric representing the state between wireless links. The number of hops from the second collection device 20 to the third slave device 30h is calculated using the information written in the LQL. Assuming that all hops "use the first MAC 103 and first PHY 102 with a low transmission rate," RPL rank 1 = 256 is calculated as follows: RPL rank 1 = (RPL rank 1 of the second collection device 20 (= 128) + MinimumHopRankIncrease - 1 (= 128) × number of hops (2) + metric (= 0)) = 384

[0142] When the DIO reception waiting time times out, the third slave device 30h selects, in the second upstream route construction unit 321, the node with the smallest RPL rank 2 on the route from the second collection device 20 to the third slave device 30h as the next upstream hop (parent node) to the second collection device 20.

[0143] 29 shows a route table 902 held by the third slave device 30h when the second slave device 20b is selected as the parent node. The third slave device 30h manages the RPL rank 1, RPL rank 2, the ID of the parent node selected based on the RPL rank 2, the type of the parent node, the wireless system with the parent node, the number of consecutive high transmission rate links (the second PHY 202 and the second MAC 203) from the second collection device 20, the presence or absence of a third slave device on the route, and the presence or absence of a first slave device on the route.

[0144] The route table 902 of the third child device 30h is as follows: *RPL rank 1=384 *RPL rank 2=128 *Parent node ID=20b *Type of parent node=second child device *Wireless system with parent node=first PHY / MAC *Continuous high transmission rate=1 *Presence or absence of third child device=Yes *Presence or absence of first child device=No

[0145] Furthermore, the third slave device 30h creates a DAO (DODAG Advertisement Object) message (DAO-2) including the parent node ID, the node type of the own node, and the wireless system with the parent node in the second multi-hop communication unit 302. The third slave device 30h transmits the DAO-2 to the second collection device 20, requests connection to the communication system 502, and completes the joining operation.

[0146] The second collection device 20 determines by the protocol determination unit 330 that DAO-2 received from the third slave device 30h should be processed by the second multi-hop communication unit 302 and the second downlink path construction unit 320. The second downlink path construction unit 320 records the parent node ID selected by the third slave device 30h and the wireless method with the parent node, which are written in DAO-2, in the downlink path table 901.

[0147] 30 shows a downstream route table 901 managed by the second collection device 20. When transmitting a downstream message addressed to the third slave device 30h, the second collection device 20 checks the nodes to be passed from the second collection device 20 to the third slave device 30h and the designated wireless method by tracing the downstream route table 901. In other words, the downstream message from the second collection device 20 to the third slave device 30h is transmitted using the second PHY / MAC to the second slave device 20b and the first PHY / MAC to the third slave device 30h.

[0148] 31 shows the wireless method bitmap and source routing header added to a downstream message addressed to the second slave device 20g in the second collection device 20. The wireless method bitmap specifies the wireless method in the order of the first hop, second hop, etc., from the top bit using a reserved area ignored by the first slave device. The wireless method is specified by a bit value of 0 if the wireless method is the first PHY / MAC, and 1 if the wireless method is the second PHY / MAC. The source routing header lists the node IDs of the nodes through which the message will be routed to its destination in hop order.

[0149] When the second handset 20b receives a downstream message containing the wireless system bitmap and source routing header, it references the wireless system bitmap and source routing header and forwards the message to the third handset 30h using the first PHY / MAC.

[0150] 32 shows a sequence when the third slave device 30c and the second slave device 20i join the communication system 502 of FIG. 4. When the third slave device 30c joins the second collection device The operation of the third slave device 30c joining the communication system 502 will be described. The third slave device 30c creates a DIS (DODAG Information Solicitation) message (DIS-1) in the first multi-hop communication unit 301. The second communication device 200 broadcasts the DIS-1 using the first MAC 103 and the first PHY 102.

[0151] The second collection device 20, which has received DIS-1 from the third slave device 30c, writes the following route information in a DIO (DODAG Information Object) message (DIO-2) in the second multi-hop communication unit 302. The second communication device 200 responds to DIS-1 by broadcasting DIO-2 using the first MAC 103 and the first PHY 102. * RPL rank 2 of the own node * MinimumHopRankIncrease-2 used in the second multi-hop communication * Wireless method compatible with the own node (first PHY 102 and first MAC 103 and second PHY 202 and second MAC 203) * Device type of the own node * Number of consecutive high transmission rates from the second collection device

[0152] The second collection device 20 holds a rank table 903 as shown in FIG. 9, and writes the following route information in DIO-2 and broadcasts it: *RPL rank 2 = 32 *MinimumHopRankIncrease-2 = 32 *Wireless system = second PHY / MAC *Device type = second collection device *Continuous high transmission rate = 0

[0153] Furthermore, the second collection device 20 describes the following route information in a DIO (DODAG Information Object) message (DIO-1) in the first multi-hop communication unit 301. The second communication device 200 responds to DIS-1 by broadcasting DIO-1 in the first MAC 103 and the first PHY 102. * RPL rank 1 of the own node * MinimumHopRankIncrease-1 used in the first multi-hop communication

[0154] The second collection device 20 holds a rank table 903 as shown in FIG. 9, and writes the following path information in DIO-1 and broadcasts it: *RPLRank1=128 *MinimumHopRankIncrease-1=128

[0155] The third slave device 30c, which receives DIO-2 and DIO-1 from the second collection device 20, determines using its protocol determination unit 330 to process DIO-2 in the second multi-hop communication unit 302 and the second upstream path construction unit 321, and to process DIO-1 in the first multi-hop communication unit 301 and the first upstream path construction unit 311.

[0156] The second upstream path construction unit 321 of the third slave device 30c calculates the RPL rank 2 of its own node from the RPL rank 2 of the second collection device 20 described in the DIO-2, the MinimumHopRankIncrease-2 described in the DIO-2, a metric representing the state of the wireless link between the second communication device 200 of the second collection device 20 and the first communication device 100 of the third slave device 30c, which is obtained when receiving the DIO-2, and a weighting of the use of the first MAC 103 and the first PHY 102, which have a lower transmission rate than the second MAC 203 and the second PHY 202.

[0157] The third slave device 30c calculates RPL rank 2=96 from the information recorded in DIO-2 of the second collecting device 20 and the metric of the wireless link as follows: RPL rank 2=(RPL rank 2 of the second collecting device 20 (=32)+MinimumHopRankIncrease-2 (=32)×low transmission rate weight (=2)+metric (=0))=96

[0158] The first upstream path construction unit 311 of the third slave device 30c calculates the RPL rank 1 of its own node from the RPL rank 1 of the second collection device 20 described in the DIO-1, the MinimumHopRankIncrease-1 described in the DIO-1, and a metric representing the state of the wireless link between the second communication device 200 of the second collection device 20 and the first communication device 100 of the third slave device 30c, which is obtained when receiving the DIO-1.

[0159] If the metric representing the state between the wireless links is 0, the third slave device 30c calculates its own node's RPL rank 1 = 256 from RPL rank 1 = 128 and MinimumHopRankIncrease-1 = 128 written in DIO-1 of the second collection device 20.

[0160] When the DIO reception waiting time times out, the third slave device 30c selects, in the second upstream route construction unit 321, the node with the smallest RPL rank 2 on the route from the second collection device 20 to the third slave device 30c as the next upstream hop (parent node) to the second collection device 20.

[0161] 33 shows a route table 902 held by the third slave device 30c when the second collection device 20 is selected as the parent node. The third slave device 30c manages the RPL rank 1, RPL rank 2, the ID of the parent node selected based on the RPL rank 2, the type of the parent node, the wireless system with the parent node, the number of consecutive high transmission rate links (the second PHY 202 and the second MAC 203) from the second collection device 20, the presence or absence of a third slave device on the route, and the presence or absence of a first slave device on the route.

[0162] The route table 902 of the third slave device 30c is as follows: *RPL rank 1=256 *RPL rank 2=96 *Parent node ID=20 *Type of parent node=Second collection device *Wireless system with parent node=First PHY / MAC *Continuous high transmission rate=0 *Presence of third slave device=Yes *Presence of first slave device=No

[0163] Furthermore, the third slave device 30c creates a DAO (DODAG Advertisement Object) message (DAO-2) including the parent node ID, the node type of the own node, and the wireless system with the parent node in the second multi-hop communication unit 302. The third slave device 30c transmits the DAO-2 to the second collecting device 20, requests connection to the communication system 502, and completes the joining operation.

[0164] The second collection device 20 determines by the protocol determination unit 330 that DAO-2 received from the third slave device 30c should be processed by the second multi-hop communication unit 302 and the second downlink path construction unit 320. The second downlink path construction unit 320 of the second collection device 20 records the parent node ID selected by the third slave device 30c, which is written in DAO-2, and the wireless method with the parent node in the downlink path table 901.

[0165] 34 shows a downstream route table 901 managed by the second collection device 20. When transmitting a downstream message addressed to the third slave device 30c, the second collection device 20 checks the nodes to be passed from the second collection device 20 to the third slave device 30c and the designated wireless method by tracing the downstream route table 901. In other words, the downstream message from the second collection device 20 to the third slave device 30c is transmitted to the third slave device 30c using the first PHY / MAC.

[0166] 35 shows the wireless method bitmap and source routing header added to a downstream message addressed to the third slave device 30c in the second collection device 20. The wireless method bitmap specifies the wireless method in the order of the first hop, second hop, etc., starting from the first bit using a reserved area ignored by the first slave device. The wireless method is specified by a bit value of 0 if the wireless method is the first PHY / MAC, or 1 if the wireless method is the second PHY / MAC. The source routing header lists the node IDs of the nodes through which the message will be routed to its destination in hop order.

[0167] When the third slave unit 30c receives the downstream message containing the wireless system bitmap and source routing header, it references the wireless system bitmap and source routing header and determines that the message is addressed to its own node.

[0168] When the second handset 20i joins via the third handset 30c, the operation of the second handset 20i joining the communication system 502 will be described. The second handset 20i creates a DIS (DODAG Information Solicitation) message (DIS-1) in the first multi-hop communication unit 301. The second communication device 200 broadcasts the DIS-1 via the first MAC 103 and the first PHY 102.

[0169] The third slave device 30c, which has received DIS-1 from the second slave device 20i, writes the following route information in a DIO (DODAG Information Object) message (DIO-2) in the second multi-hop communication unit 302. The second communication device 200 responds to DIS-1 by broadcasting DIO-2 using the first MAC 103 and the first PHY 102. * RPL rank 2 of the own node * MinimumHopRankIncrease-2 used in the second multi-hop communication * Wireless method compatible with the own node (first PHY 102 and first MAC 103 and second PHY 202 and second MAC 203) * Device type of the own node * Number of consecutive high transmission rates from the second collection device

[0170] The third handset 30c holds a route table 902 as shown in Fig. 33, and writes the following route information in DIO-2 and broadcasts it. *RPL rank 2 = 96 *MinimumHopRankIncrease-2 = 32 *Wireless system = first PHY / MAC *Device type = third handset *Continuous high transmission rate = 0 *Presence or absence of third handset = Yes *Presence or absence of first handset = No

[0171] Furthermore, the third slave device 30c describes the following route information in a DIO (DODAG Information Object) message (DIO-1) in the first multi-hop communication unit 301. The second communication device 200 responds to DIS-1 by broadcasting DIO-1 in the first MAC 103 and the first PHY 102. * RPL rank of the own node: 1 * MinimumHopRankIncrease-1 used in the first multi-hop communication

[0172] The third slave device 30c holds a route table 902 as shown in FIG. 33, and writes the following route information in DIO-1 and broadcasts it: *RPL rank 1=256 *MinimumHopRankIncrease-1=128

[0173] The second sub-device 20i, which receives DIO-2 and DIO-1 from the third sub-device 30c, determines using its protocol determination unit 330 that DIO-2 should be processed by the second multi-hop communication unit 302 and the second upstream path construction unit 321, and that DIO-1 should be processed by the first multi-hop communication unit 301 and the first upstream path construction unit 311.

[0174] The second upstream path construction unit 321 of the second slave device 20i calculates the RPL rank 2 of its own node from the RPL rank 2 of the third slave device 30c described in the DIO-2, the MinimumHopRankIncrease-2 described in the DIO-2, a metric representing the state of the wireless link between the first communication device 100 of the third slave device 30c and the second communication device 200 of the second slave device 20i, which is obtained when receiving the DIO-2, and a weighting of the use of the first MAC 103 and the first PHY 102, which have a lower transmission rate than the second MAC 203 and the second PHY 202.

[0175] The second handset 20i calculates RPL rank 2=160 from the information recorded in DIO-2 of the third handset 30c and the wireless link metric as follows: RPL rank 2=(RPL rank 2 of the third handset 30c (=96)+MinimumHopRankIncrease-2 (=32)×low transmission rate weight (=2)+metric (=0))=160

[0176] The first upstream route construction unit 311 of the second slave device 20i calculates the RPL rank 1 of its own node from the RPL rank 1 of the third slave device 30c described in the DIO-1, the MinimumHopRankIncrease-1 described in the DIO-1, and a metric representing the state of the wireless link between the first communication device 100 of the third slave device 30c and the second communication device 200 of the second slave device 20i, which is obtained when receiving the DIO-1.

[0177] If the metric representing the state between the wireless links is 0, the second slave device 20i calculates its own node's RPL rank 1 = 384 from RPL rank 1 = 256 and MinimumHopRankIncrease-1 = 128 written in DIO-1 of the third slave device 30c.

[0178] When the DIO reception waiting time times out, the second slave device 20i selects, in the second upstream route construction unit 321, the node with the smallest RPL rank 2 on the route from the second collection device 20 to the second slave device 20i as the next upstream hop (parent node) to the second collection device 20.

[0179] 36 shows a route table 902 held by the second slave device 20i when the third slave device 30c is selected as the parent node. The second slave device 20i manages the RPL rank 1, RPL rank 2, the ID of the parent node selected based on the RPL rank 2, the type of the parent node, the wireless system with the parent node, the number of consecutive high transmission rate links (the second PHY 202 and the second MAC 203) from the second collection device 20, the presence or absence of a third slave device on the route, and the presence or absence of a first slave device on the route.

[0180] The route table 902 of the second slave device 20i is as follows: *RPL rank 1=384 *RPL rank 2=160 *Parent node ID=30c *Type of parent node=third slave device *Wireless system with parent node=first PHY / MAC *Continuous high transmission rate=0 *Presence or absence of third slave device=Yes *Presence or absence of first slave device=No

[0181] Furthermore, the second slave device 20i creates a DAO (DODAG Advertisement Object) message (DAO-2) including the parent node ID, the node type of the own node, and the wireless system with the parent node in the second multi-hop communication unit 302. The second slave device 20i transmits the DAO-2 to the second collecting device 20, requests connection to the communication system 502, and completes the joining operation.

[0182] The second collection device 20 determines by the protocol determination unit 330 that DAO-2 received from the second slave device 20i should be processed by the second multi-hop communication unit 302 and the second downlink path construction unit 320. The second downlink path construction unit 320 records in the downlink path table 901 the parent node ID selected by the second slave device 20g, which is written in DAO-2, and the wireless method with the parent node.

[0183] 37 shows a downstream route table 901 managed by the second collecting device 20. When transmitting a downstream message addressed to the second slave device 20i, the second collecting device 20 checks the nodes to be passed from the second collecting device 20 to the second slave device 20i and the designated wireless method by tracing the downstream route table 901. That is, a downstream message from the second collecting device 20 to the second slave device 20i is transmitted using the first PHY / MAC to the third slave device 30c and the second PHY / MAC to the second slave device 20i.

[0184] 38 shows the wireless method bitmap and source routing header added to a downstream message addressed to the second slave device 20i in the second collection device 20. The wireless method bitmap specifies the wireless method in the order of the first hop, second hop, etc., from the top bit using a reserved area ignored by the first slave device. The wireless method is specified by a bit value of 0 if the wireless method is the first PHY / MAC, and 1 if the wireless method is the second PHY / MAC. The source routing header lists the node IDs of the nodes through which the message will be routed to its destination in hop order.

[0185] When the third handset 30c receives the downstream message containing the wireless system bitmap and source routing header, it references the wireless system bitmap and source routing header and forwards the message to the second handset 20i using the first PHY / MAC.

[0186] ● Parent node selection of second slave device 20x (second slave device 20x > third slave device 30x > first slave device 10x) In Figure 4, even if second slave device 20g is able to communicate with first slave device 10a and third slave device 30c in addition to second slave device 20b, second slave device 20g selects second slave device 20b as its parent node. RPL rank 2 calculated from the first slave device 10a = 160 RPL rank 2 calculated from the second slave device 20b = 96 RPL rank 2 calculated from the third slave device 30c = 160 (96 + 32 x 2) Similarly, in Fig. 4, even if the second slave device 20d can communicate with the second slave device 20b and the third slave device 30c in addition to the first slave device 10a, the second slave device 20d selects the second slave device 20b as its parent node. Similarly, in Fig. 4, even if the second slave device 20i can communicate with the first slave device 10a and the second slave device 20b in addition to the third slave device 30c, the second slave device 20i selects the second slave device 20b as its parent node. In this way, the second handset 20x operating under the second protocol is a wireless device that is more likely to select itself as a parent node than the first handset 10x and the third handset 30x (second handset 20x > third handset 30x, second handset 20x > first handset 10x).

[0187] 4, even if the second handset 20d can communicate with the third handset 30c in addition to the first handset 10a, the second handset 20d selects the third handset 30c as its parent node because the first handset 10a is not present on the path from the parent device. RPL Rank 2 calculated from the first handset 10a = 160 RPL Rank 2 calculated from the third handset 30c = 160 In this way, the second handset 20x operating under the second protocol is a wireless device that is more likely to select the third handset 30x as its parent node than the first handset 10x (third handset 30x > first handset 10x).

[0188] ●Selection of parent node by third slave device 30x (second slave device 20x > third slave device 30x > first slave device 10x) In Figure 4, if the third slave device 30e is able to communicate with the second slave device 20b and the third slave device 30c in addition to the first slave device 10a, the third slave device 30e selects the second slave device 20b as its parent node. RPL rank 2 calculated from the first slave device 10a = 160 RPL rank 2 calculated from the second slave device 20b = 128 RPL rank 2 calculated from the third slave device 30c = 160 (96 + 32 x 2) Similarly, in Figure 4, if the third slave device 30h can communicate with the first slave device 10a and the third slave device 30c in addition to the second slave device 20b, the third slave device 30h will select the second slave device 20b as its parent node. In this way, the third slave device 30x operating under the second protocol is a wireless device that is more likely to select the second slave device 20x as its parent node than the first slave device 10x and the third slave device 30x (second slave device 20x > third slave device 30x, second slave device 20x > first slave device 10x). 4, if the third slave device 30e can communicate with the third slave device 30c in addition to the first slave device 10a, the third slave device 30e selects the third slave device 30c, which does not have the first slave device 10a on its path from the master device, as its parent node. RPL Rank 2 calculated from the first slave device 10a = 160 RPL Rank 2 calculated from the third slave device 30c = 160 (96 + 32 x 2) Thus, the third slave device 30x operating under the second protocol is a wireless device that is more likely to select the third slave device 30x as its parent node than the first slave device 10x (third slave device 30x > first slave device 10x).

[0189] Probability of being selected as a parent node (second slave device 20x > third slave device 30x > first slave device 10x) In Figure 4, if the second slave device 20d can communicate with the second slave device 20b in addition to the first slave device 10a, the second slave device 20d selects the second slave device 20b as a parent node. RPL rank 2 calculated from the first slave device 10a = 160 RPL rank 2 calculated from the second slave device 20b = 96 Similarly, in Figure 4, if the third slave device 30e can communicate with the second slave device 20b and the third slave device 30c in addition to the first slave device 10a, the third slave device 30e selects the second slave device 20b as a parent node. RPL rank 2 calculated from the first handset 10a = 160 RPL rank 2 calculated from the second handset 20b = 128 RPL rank 2 calculated from the third handset 30c = 160 In this way, the second handset 20x operating under the second protocol is a wireless device that has a higher probability of being selected as a parent node than the first handset 10a and the third handset 30x (second handset 20x > third handset 30x, second handset 20x > first handset 10x).

[0190] 4, if the second slave device 20d can communicate with the third slave device 30c in addition to the first slave device 10a, the second slave device 20d selects the third slave device 30c, which does not have the first slave device 10a on the path from the master device, as its parent node. RPL rank 2 calculated from the first slave device 10a = 160 RPL rank 2 calculated from the third slave device 30c = 160 Similarly, in FIG. 4, if the third slave device 30e can communicate with the third slave device 30c in addition to the first slave device 10a, the third slave device 30e selects the third slave device 30c, which does not have the first slave device 10a on the path from the master device, as its parent node. RPL rank 2 calculated from the first slave device 10a = 160 RPL rank 2 calculated from the third slave device 30c = 160 In this way, the third slave device 30x operating under the second protocol is a radio device that has a higher probability of being selected as a parent node than the first slave device 10x (third slave device 30x > first slave device 10x).

[0191] Summary of First Embodiment As described above, in the first embodiment, a communication system 502 including a second collection device 20, a first slave device 10x, a second slave device 20x, and a third slave device 30x has been described. The second collection device 20, the second slave device 20x, and the third slave device 30x each transmit a DIO-1 including an RPL rank 1 used in the first multi-hop communication of the first slave device 10x, and a DIO-2 including an RPL rank 2 used in the second multi-hop communication of the second slave device and the third slave device. Therefore, while maintaining the first multi-hop communication, a second multi-hop communication is established, enabling migration of the multi-hop network. Furthermore, the calculation method for RPL rank 2 is differentiated depending on the second PHY / MAC (high transmission rate) used by the second slave device 20x and the first PHY / MAC (low transmission rate) used by the first slave device 10x and the third slave device 30x. This makes it easier for the second PHY / MAC (high transmission rate) radio used by the second slave device to be selected for the path to the second collection device, thereby enabling improvement in system throughput.

[0192] Description of a Variation of the First Embodiment Requesting Only DIO-2 In this embodiment, the second and third slave devices joining the wireless mesh network transmit DIS-1 and wait for responses from DIO-2 and DIO-1. The second and third slave devices may transmit DIS-2 to notify that their nodes support second multi-hop communication, thereby requesting only DIO-2 from the second collection device, the second slave device, and the third slave device that support second multi-hop communication. Furthermore, if no response to DIS-2 is received within a certain period of time, the second or third slave device may transmit DIO-1 and wait for DIO-1 from the first slave device. If the second and third slave devices receive only DIO-2, the protocol conversion unit 370 can calculate the number of hops from the information described in DIO-2 and calculate the RPL rank 1.

[0193] Discarding DIO-1 In this embodiment, the second and third slave devices process DIO-1 transmitted from other second and third slave devices in the first multi-hop communication unit. By recording an identifier indicating that the source is the second or third slave device in the DIO-1 of the source second and third slave devices, the second and third slave devices that receive DIO-1 may discard the DIO-1 without processing it. Alternatively, if the second and third slave devices have received DIO-2 from another second or third slave device, they may record the source node and not process DIO-1 transmitted from a node that has already received DIO-2. Even if the second and third slave devices are able to receive only DIO-2, the protocol conversion unit 370 can calculate the number of hops from the information written in DIO-2 and calculate an RPL rank of 1.

[0194] Integration of DIO-1 and DIO-2 In this embodiment, it is described that DIO-2 is transmitted in the second multi-hop communication and DIO-1 is transmitted in the first multi-hop communication. If the first slave device can ignore undefined RPL options, the second and third slave devices may add route information that is not present in DIO-1 but is described only in DIO-2 as an RPL option of DIO-1 and transmit it, thereby constructing a wireless mesh network of the second multi-hop communication and the first multi-hop communication. Alternatively, the second and third slave devices may construct a wireless mesh network of the second multi-hop communication and the first multi-hop communication by writing route information that is not present in DIO-1 but is described only in DIO-2 in a reserved area of ​​DIO-1 that is ignored by the first slave device and transmitting it.

[0195] ●Downstream message format In this embodiment, the wireless method (second PHY / MAC or first PHY / MAC) used when the second collection device sends a downstream message to the child device is specified in bitmap format, but the TLV (Type-Length-Value) format may also be used.

[0196] ●Continued Use of the First Collector 10 In this embodiment, the second collector 20 is used for the RPL DAGRoot, but the first collector 10 may also be used for the RPL DAGRoot. Even when the first collector 10 is used, the second and third slave devices can calculate the RPL rank 2 from the contents of DIO-1 through the operation of the protocol conversion unit 370. Therefore, DIO-2 and DIO-1 can be transmitted downstream from the second and third slave devices (assuming traffic addressed to the collector device is upstream). In this case, the first collector 10 ignores the wireless system and node type information with the parent node notified by DAO-2 from the second and third slave devices, and only the destination ID and the parent node of that node are registered in the downstream route table 901. In this case, since the first collection device 10 cannot specify the wireless system when transmitting downstream traffic, all nodes forward downstream traffic using the first PHY / MAC. Therefore, before the first collection device 10 replaces the second collection device 20, it is possible to replace the first slave device with the second slave device or the third slave device.

[0197] Weighting Type In this embodiment, the transmission rate of the wireless link of the second slave device is compared with the transmission rate of the wireless link of the first and third slave devices, and the transmission rate of the wireless link of the first and third slave devices is set to the low transmission rate. When calculating RPL rank 2, RPL rank 2 is calculated by multiplying MinimumHopRankIncrease-2 by a coefficient (low transmission rate weighting), but RPL rank 2 may also be calculated by a method that adds the cost for using a low transmission rate.

[0198] ●Weighting of RPL rank values ​​In this embodiment, the RPL rank values ​​are weighted (weighted four times) based on the difference in transmission rate of the wireless link, but they may also be weighted based on packet loss rate, delay, throughput, and their average and variance, etc.

[0199] In this embodiment, the RPL metric is the Link Quality Level (LQL), which ranks nodes according to their received power levels. Other metrics that may be used include the Expected Transmission Count (ETX), packet loss rate, delay, throughput, and the remaining battery capacity of the node.

[0200] Line Type In this embodiment, the case of wireless communication is shown, but wired communication may also be included in part.

[0201] Embodiment 2. In the first embodiment, a sequence for constructing a wireless mesh network with the second collection device 20, the first slave device 10x, the second slave device 20x, and the third slave device 30x has been described. In the second embodiment, differences from the first embodiment will be described. In the second embodiment, parent node selection based on RPL rank 2, which is an index for route selection in the second multi-hop communication, will be described in the second slave device 20x and the third slave device 30x.

[0202] Fig. 39 is a flowchart showing parent node selection in the second and third slave devices. Fig. 40 shows a situation in which the second slave device 20d joins a wireless mesh network configured with the second collection device 20 and the first slave device 10a, the second slave device 20b, and the second slave device 20c.

[0203] The second slave device 20d receives DIO-1 from the first slave device 10a and DIO-2 and DIO-1 from the second slave device 20c by the process described in embodiment 1. The second slave device 20d calculates the RPL rank 2 when the first slave device 10a is selected as the parent node and the RPL rank 2 when the second slave device 20c is selected as the parent node. A low transmission rate weight (=2) is applied by using the wireless link 601. The RPL rank 2 when the first slave device 10a is selected as the parent node is 160 (rank of the second collection device (=32) + MinimumHopRankIncrease-2 (=32) × number of hops (=2) × low transmission rate weight (=2) + metric (=0)).

[0204] On the other hand, when the second slave device 20c is selected as the parent node, the RPL rank 2 is 128 (RPL rank 2 of the second slave device 20c (=96)+MinimumHopRankIncrease-2 (=32)+Metric (=0)).

[0205] Under this condition, step S001 in the flowchart for selecting a parent node in the second and third child devices in Figure 39 becomes Yes, and in step S002, the second child device 20d selects the second child device 20c, which has the smallest RPL rank 2, as its parent node.

[0206] FIG. 41 shows a situation in which a second slave 20d joins a wireless mesh network configured with a second collection device 20, a first slave 10a, a second slave 20b, and a third slave 30c.

[0207] The second slave device 20d receives DIO-1 from the first slave device 10a and DIO-2 and DIO-1 from the third slave device 30c according to the process described in the first embodiment. The second slave device 20d calculates the RPL rank 2 when the first slave device 10a is selected as the parent node and the RPL rank 2 when the third slave device 30c is selected as the parent node. A low transmission rate weight (=2) is applied by using the wireless link 601. The RPL rank 2 when the first slave device 10a is selected as the parent node is 160 (rank of the second collection device (=32) + MinimumHopRankIncrease-2 (=32) × number of hops (=2) × low transmission rate weight (=2) + metric (=0)).

[0208] On the other hand, when the third child device 30c is selected as the parent node, the RPL rank 2 becomes 192 (RPL rank 2 of the third child device 30c (= 128) + MinimumHopRankIncrease - 2 (= 32) x low transmission rate weight (= 2) + metric (= 0)).

[0209] Under this condition, step S001 in the flowchart for selecting a parent node in the second and third slave units in Figure 39 becomes Yes, and step S002 causes the second slave unit 20d to select the first slave unit 10a, which has the smallest RPL rank 2, as its parent node.

[0210] 42 and 43 show a situation in which a second slave 20d joins a wireless mesh network configured with a second collection device 20, a first slave 10a, and second slaves 20b, 20c, and 20e. The second slave 20d receives DIO-1 from the first slave 10a and DIO-2 and DIO-1 from the second slave 20e through the processing described in embodiment 1. The second slave 20d calculates an RPL rank 2 when the first slave 10a is selected as the parent node and an RPL rank 2 when the second slave 20e is selected as the parent node. A low transmission rate weight (=2) is applied by using the wireless link 601. When the first slave device 10a is selected as the parent node, the RPL rank 2 is 160 (rank of the second collection device (= 32) + MinimumHopRankIncrease-2 (= 32) x number of hops (= 2) x low transmission rate weighting (= 2) + metric (= 0)).

[0211] On the other hand, when the second slave device 20e is selected as the parent node, the RPL rank 2 is 160 (RPL rank 2 of the second slave device 20e (=128)+MinimumHopRankIncrease-2 (=32)+Metric (=0)).

[0212] Under these conditions, step S001 in the flowchart for selecting a parent node in the second and third slave units in Figure 39 becomes No, step S003 becomes Yes, and step S004 causes the second slave unit 20d to select the second slave unit 20e, which has the largest value of consecutive high transmission rates, as its parent node.

[0213] 44 and 45 show a situation in which a second slave 20d joins a wireless mesh network configured with a second collection device 20, a first slave 10a, and third slaves 30b, 30c, and 30e.

[0214] The second slave device 20d receives DIO-2 and DIO-1 from the third slave devices 30e and 30c by the processing described in embodiment 1. The second slave device 20d calculates the RPL rank 2 when the third slave device 30e is selected as the parent node, and the RPL rank 2 when the third slave device 30c is selected as the parent node.

[0215] A low transmission rate weight (=2) is applied by using the wireless link 601. When the third slave device 30e is selected as the parent node, the RPL rank 2 is 224 (RPL rank 2 of the third slave device 30e (=160) + MinimumHopRankIncrease-2 (=32) × low transmission rate weight (=2) + metric (=0)).

[0216] On the other hand, when the third child device 30c is selected as the parent node, the RPL rank 2 is 224 (RPL rank 2 of the third child device 30c (= 160) + MinimumHopRankIncrease - 2 (= 32) x low transmission rate weight (= 2) + metric (= 0)).

[0217] Under this condition, step S001 in the flowchart for selecting a parent node in the second and third child devices in Figure 39 becomes No, step S003 becomes No, and step S005 becomes Yes, and in step S006, the second child device 20d selects the third child device 30c, which does not have a first child device on its path, as its parent node.

[0218] FIG. 46 shows a situation in which a second slave device 20d joins a wireless mesh network configured with a second collection device 20 and first slave devices 10a, 10b, 10c, and 10e.

[0219] The second slave unit 20d receives DIO-1 from the first slave units 10e and 10c by the processing described in embodiment 1, and calculates the RPL rank 2 when the first slave unit 10e is selected as the parent node and the RPL rank 2 when the first slave unit 10c is selected as the parent node.

[0220] A low transmission rate weight (=2) is applied by using the wireless link 601. The RPL rank 2 when the first slave device 10e is selected as the parent node is 224 (RPL rank 2 of the second collection device 20 (=32) + MinimumHopRankIncrease-2 (=32) × low transmission rate weight (=2) × number of hops (=3) + metric (=0)).

[0221] Similarly, when the first slave device 10c is selected as the parent node, the RPL rank 2 is 224 (RPL rank 2 of the second collection device 20 (= 32) + MinimumHopRankIncrease-2 (= 32) x low transmission rate weighting (= 2) x number of hops (= 3) + metric (= 0)).

[0222] Under this condition, step S001 in the flowchart for selecting a parent node in the second and third slave units in Figure 39 becomes No, step S003 becomes No, and step S005 becomes No, and step S007 causes the second slave unit 20d to randomly select either the first slave unit 10e or the first slave unit 10c as the parent node.

[0223] As described above, in the second embodiment, when selecting a parent node based on RPL rank 2, if there are multiple parent node candidates with the same RPL rank 2 value, the number of consecutive high transmission rates from the second collection device 20 and the presence or absence of a first child device on the route are used. This allows for preferential selection of a route in which the vicinity of the second collection device 20 is configured with a high transmission rate wireless link 602, and makes it possible to improve system throughput by avoiding the passage through the first child device, which can become a traffic bottleneck.

[0224] In the second embodiment, when the RPL rank values ​​of the paths from the node to the second collection device are the same, an example is shown in which a path in which the first child device does not exist is selected. However, when there are paths in which the RPL rank values ​​are the same and the first child device exists and the third child device exists, one of the paths may be selected at random.

[0225] Embodiment 3. In the first embodiment, the second slave device 20x and the third slave device 30x transmit DIO-2 and DIO-1, thereby replacing the first slave device 10x with the second slave device 20x and the third slave device 30x. In the third embodiment, differences from the first embodiment will be described. In the third embodiment, a method for stopping transmission of DIO-1 in a network in which the node replacement is completed and the first slave device does not exist will be described.

[0226] FIG. 47 shows a state of a communication system 503 in which the first handset 10x in the communication system 502 has been replaced with a second handset 20x and a third handset 30x.

[0227] 48 shows a sequence of transmitting DIO-2 and DIO-1 in the second collecting device 20, the second slave devices 20b, 20f, 20g, and the third slave device 30h in FIG. 47. The second collecting device 20, the second slave devices 20b, 20f, 20g, and the third slave device 30h transmit DIO-2 and DIO-1 every time the Trickle timer defined in the RPL expires. The administrator 1000 notifies the second collecting device 20 via the input interface 930 that the first slave device 10x does not exist in the communication system 503. When the second multi-hop communication unit 302 of the second collection device 20 receives a notification from the input interface 930 that the first child device 10x does not exist, it sets a flag indicating that the first child device 10x does not exist in DIO-2 and transmits it, and stops transmission from DIO-1, starting after the next Trickle timer expires.

[0228] When the second handset 20b, 20f, 20g and the third handset 30h receive DIO-2 with a flag set to indicate that the first handset 10x does not exist, they set a flag to DIO-2 indicating that the first handset 10x does not exist and transmit it, after the next expiration of the Trickle timer, and stop transmitting DIO-1.

[0229] As described above, in this embodiment, the second collection device 20 is notified that the first child device does not exist, and a flag is held in DIO-2 to notify the second collection device, the second child device, and the third child device that the first child device does not exist, thereby stopping transmission from DIO-1 and improving wireless usage efficiency.

[0230] In the third embodiment, the administrator 1000 directly instructs the second collecting device 20 that the first slave device is not present. As another instruction method, the second collecting device may be connected to an external network such as the Internet and an instruction to stop transmission of DIO-1 may be given from an external server or system. Furthermore, the second collecting device may check the type of node participating in the communication system 503 and determine that the first slave device is not present, thereby autonomously determining to stop transmission of DIO-1. Alternatively, the second slave device and the third slave device may determine that they have not received DIO-1 from the first slave device for a certain period of time and autonomously determine to stop transmission of DIO-1.

[0231] Summary and Supplementary Explanation In the first, second, and third embodiments, a case has been described in which migration is realized from existing wireless devices (first collection device 10, first slave device 10x) to new wireless devices (second collection device 20, second slave device 20x, third slave device 30x) in a wireless mesh network using RPL. The communication system 501 calculates only RPL rank 1 (first rank value) to select a master device. The communication system 502 calculates RPL rank 1 (first rank value) and RPL rank 2 (second rank value) to select a master device. The new wireless device (second collection device 20: master device) that becomes the DAGROOT supports the existing communication method (first PHY / MAC) and the existing first protocol, as well as the new communication method (second PHY / MAC) and the new second protocol. Some new wireless devices (second handset 20x) support an existing communication method (first PHY / MAC) and an existing first protocol, and a new communication method (second PHY / MAC) and a new second protocol. Some new wireless devices (third handset 30x) support an existing communication method (first PHY / MAC), an existing first protocol, and a new second protocol.

[0232] Control Messages (DIO-1 and DIO-2) The new wireless device (second collection device 20: parent device), the new wireless device (second slave device 20x), and the new wireless device (third slave device 30x) transmit a control message (DIO-2) for the new wireless device (second slave device 20x, third slave device 30x) and a control message (DIO-1) for the existing wireless device (first slave device 10x). The control message (DIO-2) for the new wireless device (second slave device 20x, third slave device 30x) is formatted so that it is discarded by the existing wireless device (first slave device 10x). The control message (DIO-2) for the new wireless device (second slave device 20x, third slave device 30x) describes any or all of the following route information: (1) RPL rank of the own node (2) On the path from the parent device to the own node, (2A) the number of consecutive new communication methods (second PHY / MAC) (2B) Whether or not there is an existing wireless device (first child device 10x) (2C) Whether or not there is a new wireless device (third child device 30x) By specifying a flag in the control message (DIO-2) for the new wireless device (second child device 20x, third child device 30x), the control message (DIO-1) for the existing wireless device (first child device 10x) can be stopped.

[0233] New wireless devices (second handset 20x, third handset 30x) The new wireless devices (second handset 20x, third handset 30x) calculate and store RPL rank values ​​(RPL rank 2 and RPL rank 1) in the control message (DIO-2) for the new wireless devices (second handset 20x, third handset 30x) and the control message (DIO-1) for the existing wireless device (first handset 10x). The new wireless devices (second handset 20x, third handset 30x) use the RPL rank value (RPL rank 2) calculated in the control message (DIO-2) for the new wireless devices (second handset 20x, third handset 30x) to select a parent node.

[0234] In the case where the new wireless devices (second handset 20x, third handset 30x) can only receive the control message (DIO-1) for the existing wireless device (first handset 10x), the protocol conversion unit 370 assumes that all hops from the parent device have passed through the existing wireless device (first handset 10x) and calculates the RPL rank value (RPL rank 2). In the case where the new wireless devices (second handset 20x, third handset 30x) can only receive the control message (DIO-2) for the new wireless devices (second handset 20x, third handset 30x), the protocol conversion unit 370 calculates the number of hops from the information described in DIO-2 and calculates the RPL rank value (RPL rank 1) of the existing wireless device (first handset 10x). If the new radio device (second handset 20x, third handset 30x) uses LQL as the link metric of the RPL, it obtains the number of hops and the metric value for each hop from the information described in the LQL and calculates the RPL rank value (RPL rank 1) of the existing radio device (first handset 10x).

[0235] ●Setting and Calculating Rank Values ​​The communication system 502 sets the RPL rank values ​​in advance as follows, so that when calculating the RPL rank values, it is possible to calculate RPL rank 2 (second rank value) from RPL rank 1 (first rank value). (1) Initial rank values ​​pre-stored in the second collecting device 20 RPLRank1>RPLRank2 RPLRank1=RPLRank2×4 (2) Minimum increase value per hop pre-stored in the second collecting device 20 MinimumHopRankIncrease-1>MinimumHopRankIncrease-2 MinimumHopRankIncrease-1=MinimumHopRankIncrease-2×4 (3) Minimum increase value per hop pre-stored in the second slave device 20x and the third slave device 30x MinimumHopRankIncrease-1>MinimumHopRankIncrease-2 MinimumHopRankIncrease-1=MinimumHopRankIncrease-2x4

[0236] Priority of parent device selection When a control message (DIO-2) for a new wireless device (second handset 20x, third handset 30x) is used to calculate the RPL rank value (RPL rank 2) and select a parent node, the following applies:

[0237] (1) When calculating RPL rank 2 (second rank value), the minimum increase value to be added to the RPL rank value for each hop in the RPL is weighted so that there is a difference in the increase value to be added to the RPL rank value for each hop in the RPL when a new communication method (second PHY / MAC) is used and when an existing communication method (first PHY / MAC) is used, and RPL rank 2 (second rank value) is calculated.

[0238] (2) When selecting a parent node, if there are multiple parent node candidates with the same RPL rank, the parent node is selected in the following order of priority: (2A) The parent node with the largest number of consecutive new communication methods (second PHY / MAC) (2B) The parent node with no existing wireless device (first slave device 10x) on the path from the parent device to the node itself, or the parent node with no new wireless device (third slave device 30x) on the path from the parent device to the node itself.

[0239] ● Announcement Message (DAO-1 and DAO-2) The existing wireless device (first child device 10x) notifies the parent node ID in the announcement message (DAO-1) sent to the parent device. The new wireless devices (second child device 20x, third child device 30x) record the parent node ID and the wireless method (PHY / MAC) used for communication with the parent node in the route table 902. The new wireless devices (second child device 20x, third child device 30x) notify the parent node ID, the device type of their own node, and the wireless method (PHY / MAC) used for communication with the parent node in the announcement message (DAO-2) sent to the parent device. The parent device stores the ID of the node selected by the child node as the parent node and the wireless method (PHY / MAC) used for transmission to that node in the downlink route table 901.

[0240] Downstream traffic operation of the parent device (1) The new wireless device (parent device) stores the wireless system (PHY / MAC) supported by each wireless device (child device) in the downstream route table 901. (2) When sending downstream traffic, the new wireless device (parent device) specifies the wireless device (child device) to be routed through and the wireless system (PHY / MAC) to be used for the hop. The new wireless device (parent device) uses a bitmap as a method for specifying the wireless system. Alternatively, the new wireless device (parent device) uses a TLV as a method for specifying the wireless system. (3) If there is a wireless device (child device) whose wireless system (PHY / MAC) is unknown, the new wireless device (parent device) specifies the existing wireless system (first PHY / MAC).

[0241] ●Downstream traffic operation of existing radio device (first slave device 10x) (1) When the existing radio device (first slave device 10x) forwards a downstream message in downstream traffic, it uses the ID of the destination radio device described in the downstream message and uses the existing radio method (first PHY / MAC).

[0242] Downstream traffic operation of new wireless device (second handset 20x) (1) When a new wireless device (second handset 20x) transfers a downstream message in downstream traffic, it uses the ID of the destination wireless device described in the downstream message and the wireless method (PHY / MAC) to be used for transfer. (2) If a wireless method (PHY / MAC) is not specified, it uses the existing wireless method (first PHY / MAC).

[0243] ●Downstream traffic operation of new radio device (third handset 30x) (1) When the new radio device (third handset 30x) forwards a downstream message in downstream traffic, it uses the ID of the destination radio device described in the downstream message and uses the existing wireless method (first PHY / MAC).

[0244] The features of the above-described embodiment are described below. A communication system 501 connects a master (first collection device 10) and multiple slaves (first slave device 10x) to a wireless mesh network constructed based on a first rank value (RPL rank 1) calculated using a first protocol. A communication system 502 includes a master (second collection device 20) and multiple slaves (first slave device 10x, second slave device 20x, third slave device 30x). The slaves (first slave device 10x, second slave device 20x, third slave device 30x) serve as nodes and are connected to the wireless mesh network. The slaves (second slave device 20x, third slave device 30x) replace the first slave device 10x of the communication system 501. The slave devices (second slave device 20x, third slave device 30x) include a communication device (second communication device 200), a protocol determination unit 330, an upstream route construction unit 360, and a multi-hop communication unit 340. The communication device (second communication device 200) receives one or more control messages (DIO-1, DIO-2) including route information related to route construction from one or more neighboring nodes (parent device or slave device). The route information includes node rank information. The protocol determination unit 330 determines whether to process the rank information using a first protocol or a second protocol. The protocol determination unit 330 determines the type of control message (DIO-1 or DIO-2) for each of the one or more control messages, and determines whether to process the control message using the first protocol or the second protocol. Based on the determination result of the protocol determination unit 330, the upstream route construction unit 360 calculates a first rank value (RPL rank 1) using rank information based on the first protocol, and calculates a second rank value (RPL rank 2) using rank information based on the second protocol. The first rank value (RPL rank 1) and the second rank value (RPL rank 2) are different values. The upstream route construction unit 360 selects one node as a parent node from one or more neighboring nodes based on one or more second rank values ​​(RPL rank 2). The upstream route construction unit 360 records the first rank value (RPL rank 1) and the second rank value (RPL rank 2) calculated using the parent node ID and the parent node rank information in the route table 902.The multi-hop communication unit 340 creates a notification message that notifies the parent node ID recorded in the route table 902 from the child node, and transmits the message to the parent device.

[0245] A communication device (second communication device 200) receives, as control messages, from one node: a first control message (DIO-1) including first rank information of the source node in its route information; and a second control message (DIO-2) including second rank information of the source node in its route information. The slave device has a first upstream route construction unit 311 and a second upstream route construction unit 321. The first upstream route construction unit 311 calculates a first rank value based on the first rank information of the source node. The second upstream route construction unit 321 calculates a second rank value based on the second rank information of the source node.

[0246] The rank information includes at least either first rank information or second rank information. The rank information includes a rank value and a minimum increase value of the rank value. The first rank information includes a first rank value (RPL Rank 1) and a first minimum increase value (MinimumHopRankIncrease-1). The second rank information includes a second rank value (RPL Rank 2) and a second minimum increase value (MinimumHopRankIncrease-2).

[0247] When a communication device (second communication device 200) receives only a first control message from one slave device as a control message, the first control message including first rank information in the route information, (1) the first upstream route construction unit 311 calculates a first rank value (RPL rank 1) based on the first rank information, and (2) the protocol conversion unit 370 calculates a second rank value (RPL rank 2) by weighting the second minimum increase value for all hops from the master device to the slave device.

[0248] When a communication device (second communication device 200) receives only a second control message from one slave device as a control message, the second control message including second rank information in the route information, (1) the protocol conversion unit 370 calculates the number of hops from the route information and calculates a first rank value based on the number of hops, and (2) the second upstream route construction unit 321 calculates a second rank value (RPL rank 2) based on the second rank information.

[0249] When calculating the second rank value (RPL rank 2), the second uplink route construction unit 321 calculates the second rank value by applying a weight so that the second rank value differs when the second communication method is used and when the first communication method is used.

[0250] The route information includes the number of consecutive routes of the second communication method (second PHY / MAC) on the route from the parent device. When selecting a parent node, if there are multiple nodes with the same rank value, the upstream route construction unit 360 selects the parent node based on the number of consecutive routes.

[0251] The route information includes whether or not there are nodes on the route from the parent device that are incapable of the second communication method (second PHY / MAC) (first child device 10x and third child device 30x that are only capable of the first communication method (first PHY / MAC)).When selecting a parent node, if there are multiple nodes with the same rank value, the upstream route construction unit 360 selects the parent node based on whether or not there are nodes (first child device 10x or third child device 30x) that are incapable of the second communication method (second PHY / MAC).

[0252] The path information includes the type of parent node (parent device, first child device 10x, second child device 20x, third child device 30x). The upstream path construction unit 360 selects a communication method with the parent node based on the type of parent node (parent device, first child device 10x, second child device 20x, third child device 30x) and the type of child node (first child device 10x, second child device 20x, third child device 30x), and records the communication method with the parent node in the path table 902. Alternatively, the upstream path construction unit 360 selects a communication method with the parent node based on the communication method of the parent node (first communication method or second communication method) and the communication method of the child node (first communication method or second communication method), and records the communication method with the parent node in the path table 902. The upstream path construction unit 360 selects the second communication method as the communication method with the parent node only when the type of the parent node is the parent device or the second child device 20x and the type of the child node is the second child device 20x.

[0253] When the parent node and child node respectively support the first communication method (first PHY / MAC) and the second communication method (second PHY / MAC), the upstream path construction unit 360 selects the second communication method (second PHY / MAC) as the communication method with the parent node.

[0254] If the parent node and child node each support a first communication method (first PHY / MAC) and either the parent node or the child node does not support a second communication method (second PHY / MAC), the upstream path construction unit 360 selects the first communication method (first PHY / MAC) as the communication method with the parent node.

[0255] A slave communication device (first communication device 100 or second communication device 200) receives a downlink message including the IDs of nodes present on a path to the slave device sending the downlink message and the communication method with the nodes. The first multi-hop communication unit 301 of the first slave device 10x identifies the IDs of the child nodes by referring only to the node IDs included in the downlink message, and forwards the downlink message to the child nodes. The multi-hop communication units 340 of the second slave device 20x and the third slave device 30x identify the IDs of the child nodes and the communication method with the child nodes by referring to the node IDs and communication method with the nodes included in the downlink message, and forwards the downlink message to the child nodes.

[0256] The parent device (second collection device 20) is connected to a wireless mesh network in which the parent device and multiple child devices communicate as nodes. The parent device (second collection device 20) includes a communication device (second communication device 200), a downlink path construction unit 350, and a multi-hop communication unit 340. The communication device (second communication device 200) receives a notification message (DAO-2) from a child node (second child device 20x, third child device 30x) notifying the parent node ID and the communication method with the parent node. The downlink path construction unit 350 records the parent node ID and the communication method with the parent node included in the notification message (DAO-2) in a downlink path table 902, corresponding them to the child node ID. The multi-hop communication unit 340 refers to the downlink path table 902 to identify one or more nodes on a path to the child device that sends a downlink message, and creates a downlink message including the node ID and the communication method with the node.

[0257] Downstream route construction unit 350 records first rank information (first rank value and MinimumHopRankIncrease-1) and second rank information (second rank value and MinimumHopRankIncrease-2) in rank table 903. Multihop communication unit 340 creates a first control message (DIO-1) including the first rank information and a second control message (DIO-2) including the second rank information, and transmits the first control message and the second control message to neighboring nodes.

[0258] The parent device (second collection device 20) and the child devices (second child device 20x, third child device 30x) are connected to a wireless mesh network that can communicate using the first protocol and the second protocol, and by stopping communication using the first protocol, they communicate only using the second protocol.

[0259] In the communication system 503, the parent device (second collection device 20) and the child devices (second child device 20x, third child device 30x) communicate only using the second protocol. The parent device (second collection device 20) transmits a downstream message including a node ID and a communication method with the node. The child devices (second child device 20x, third child device 30x) receive the downstream message, identify the child node ID and the communication method with the child node by referring to the node ID and communication method with the node included in the downstream message, and transfer the downstream message to the child node.

[0260] Fourth Embodiment In the first embodiment, a wireless mesh network is constructed with the second collection device 20, the first slave device 10x, the second slave device 20x, and the third slave device 30x, and a method has been described in which the second collection device 20 refers to the downlink route table 901 when transmitting a downlink message from the second collection device 20 and specifies a wireless system.

[0261] In the fourth embodiment, differences from the first embodiment will be described. In the present embodiment, a method will be described in which the second collection device 20 determines the downstream route and the wireless method when transmitting a downstream message using a downstream route table in a format different from the downstream route table 901.

[0262] Figure 49 shows a network in which a first terminal 10x, a second terminal 20x, and a third terminal 30x coexist in a communication system 504. In Figure 49, the first terminal 10x, the second terminal 20x, and the third terminal 30x are assumed to be able to use the Hop-by-Hop extension header of IPv6 (Internet Protocol Version 6). The Hop-by-Hop extension header is an area defined as an extension portion of the header in the IPv6 format. The Hop-by-Hop extension header is an area that can store information that should be referenced or processed by all nodes on the path of the IPv6 packet.

[0263] ●Second slave device 20b Figure 50 shows a situation in which the upstream message sent by the second slave device 20b uses the IPv6 Hop-by-Hop extension header to describe the wireless type of the nodes and links passed through to the second collection device.

[0264] ●Operation of child device (assigning child device ID and wireless method) The second child device 20b uses the multi-hop communication unit 340 to write an identifier: 1 and the ID: 20b of the second child device 20b in the Hop-by-Hop extension header, indicating that the second PHY / MAC was used as the wireless method for transmission to the parent node (the second collection device 20 in Figure 50), and sends an upstream message to the parent node, the second collection device 20.

[0265] The second slave device 20b may transmit an upstream message of this embodiment to the parent node at any time after the second slave device 20b has completed the operation of joining the communication system 504. Specifically, the following cases are possible: (1) When the slave device has completed the operation of joining the communication system 504; (2) When the slave device has changed its parent node and changed its route; (3) When all upstream messages are sent from the slave device to the parent device; (4) When periodically sending messages from the slave device to the parent device; (5) When a combination of the above (1) to (4) is performed.

[0266] ●Operation of parent device (receiving child device ID and wireless method) Figure 51 shows a situation in which the second collection device 20, having received an upstream message from the second child device 20b, registers the wireless method bitmap and passing nodes to be used for the downstream message to the second child device 20b in the passing node information table 904, which becomes part of the downstream route table.

[0267] When the second collection device 20 receives an upstream message from the second slave device 20b, the second downstream path construction unit 320 acquires the wireless method and transit nodes from the Hop-by-Hop extension header and creates a wireless method bitmap and source routing header addressed to the second slave device 20b. The second collection device 20 registers the information of the source routing header and wireless method bitmap in the transit node information table 904 as a source routing header and wireless method bitmap addressed to the second slave device 20b.

[0268] A destination ID, a source routing header, and a wireless communication method bitmap are registered in the passing node information table 904. The passing node information table 904 is also called a source routing table.

[0269] FIG. 51 shows a case where only the second slave device 20 b is registered in the passed node information table 904 .

[0270] When the second collection device 20 sends a downstream message addressed to the second slave device 20b, if the second slave device 20b is registered in the transit node information table 904, the second collection device 20 uses the source routing header and wireless method bitmap of the second slave device 20b.

[0271] ●Second slave device 20r Figure 52 shows a situation in which the upstream message sent by the second slave device 20r uses the IPv6 Hop-by-Hop extension header to describe the wireless type of the nodes and links passed through to the second collection device.

[0272] 52, it is assumed that the second slave device 20s, the first slave device 10f, and the second slave device 20l have already completed the operation of joining the communication system 504. It is assumed that the wireless methods for transmission to the parent node of the second slave device 20s, the first slave device 10f, and the second slave device 20l are the second PHY / MAC, the first PHY / MAC, and the first PHY / MAC, respectively.

[0273] ●Operation of the child device (assigning the child device ID and wireless method) The second child device 20r writes an identifier: 1 and the ID: 20r of the second child device 20r in the Hop-by-Hop extension header using the multi-hop communication unit 340, indicating that the second PHY / MAC was used as the wireless method for transmission to the parent node, and sends an upstream message to the second child device 20l, which is the parent node.

[0274] The second slave device 20l, which receives an upstream message from the second slave device 20r to the second collection device 20, writes an identifier: 0 and the ID: 20l of the second slave device 20l in the Hop-by-Hop extension header using the multi-hop communication unit 340, indicating that the first PHY / MAC was used as the wireless method for transmission to the parent node, and transmits the upstream message to the first slave device 10f, which is the parent node.

[0275] The first slave device 10f, which receives an upstream message from the second slave device 20l to the second collection device 20, writes an identifier: 0 indicating that the first PHY / MAC was used as the wireless method for transmission to the parent node and the ID: 10f of the first slave device 10f in the Hop-by-Hop extension header using the first multi-hop communication unit 301, and transmits the upstream message to the second slave device 20b, which is the parent node.

[0276] The second slave device 20b, which receives an upstream message from the first slave device 10f to the second collection device 20, writes an identifier: 1 and the ID: 20b of the second slave device 20b in the Hop-by-Hop extension header using the multi-hop communication unit 340, indicating that the second PHY / MAC was used as the wireless method for transmission to the parent node, and transmits the upstream message to the second collection device 20, which is the parent node.

[0277] The second slave device 20r may transmit the upstream message of this embodiment to the parent node at any time after the second slave device 20r completes the operation of joining the communication system 504. The second slave device 20r may transmit the upstream message of this embodiment to the parent node before the second slave device 20l, the first slave device 10f, and the second slave device 20b transmit the upstream message of this embodiment to the parent node.

[0278] ●Operation of parent device (receiving child device ID and wireless method) Figure 53 shows a situation in which the second collection device 20, having received an upstream message from the second child device 20r, registers the wireless method bitmap and passing nodes to be used for the downstream message to the second child device 20r in the passing node information table 904, which becomes part of the downstream route table.

[0279] When the second collection device 20 receives an upstream message from the second slave device 20r, the second downstream route construction unit 320 obtains the wireless method and the nodes to be passed through from the Hop-by-Hop extension header, and sorts them in reverse order to create a wireless method bitmap and source routing header addressed to the second slave device 20r.

[0280] The second collection device 20 registers the information of the source routing header and the wireless communication method bitmap in the transit node information table 904 by the second downstream route construction unit 320 as a source routing header and a wireless communication method bitmap addressed to the second slave device 20r.

[0281] The transit node information table 904 registers a destination ID, a source routing header, and a wireless system bitmap.

[0282] In the source routing header, all nodes to be passed from the second collection device 20 to the destination node are listed in the order of passing.

[0283] The wireless communication method bitmap lists the wireless communication methods with the parent nodes of all the nodes along the route from the second collection device 20 to the destination node in the order of the nodes along the route.

[0284] 53 shows a case where the second slave device 20b and the second slave device 20r have transmitted upstream messages of this embodiment to the parent node, and as a result, the second slave device 20b and the second slave device 20r are registered in the passed-through node information table 904. The passed-through node information table 904 can register the second slave device 20r even in a state where the second slave device 20l and the first slave device 10f have not transmitted upstream messages of this embodiment to the parent node.

[0285] When the multi-hop communication unit 340 of the second collection device 20 sends a downstream message addressed to the second slave device 20r, if the second slave device 20r is registered in the transit node information table 904, the multi-hop communication unit 340 uses the source routing header and wireless method bitmap of the second slave device 20r.

[0286] As described above, when transmitting or forwarding an upstream message addressed to a parent device, a child device in communication system 504 of embodiment 4 writes the node ID and communication method of the child device in the upstream message so that the order of the child devices can be determined. The parent device stores the node ID and communication method written in the upstream message in a memory or storage device, and uses the stored node ID and communication method to create a downstream message for the child device that sent the upstream message addressed to the parent device.

[0287] Summary of the Fourth Embodiment The communication system 504 of the fourth embodiment has a feature of recording the wireless method used in the wireless multi-hop network and using the recorded wireless method as is for the downlink route. When the communication system 504 of the fourth embodiment receives information about the uplink route including the wireless method, the communication system 504 uses the information about the uplink route to construct the downlink route including the wireless method.

[0288] When the multi-hop communication unit 340 (including the first multi-hop communication unit 301) of the child device (child node) creates an upstream message addressed to the parent device and sends it to the parent device, it creates an upstream message that includes the ID of its own node and the communication method with the parent node and sends it to the parent device.

[0289] When the multi-hop communication unit 340 (including the first multi-hop communication unit 301) of the child device (child node) receives an upstream message and forwards it to the parent device, it includes the ID of its own node and the communication method with the parent node in the upstream message and sends it to the parent device.

[0290] When a child device (child node) sends or forwards an upstream message addressed to a parent device, it assigns its own ID and the communication method with the parent node to the upstream message. An upstream message addressed to a parent device notifies the parent device of the route (all nodes the upstream message passed through) and communication method used in the upstream message forwarding.

[0291] The parent device's downstream route construction unit 350 acquires the transit nodes and communication methods attached to the upstream message received from the child node, sorts them in reverse order, and records them in the transit node information table 904 (source routing table).

[0292] When sending a downstream message to a child node, the second downstream route construction unit 320 of the parent device searches the transit node information table 904 (source routing table) for the target node ID and obtains the route and communication method to be used.

[0293] When the second downlink route construction unit 320 of the parent device receives an uplink message from a child node that contains the ID of the via node through which the uplink message passed and the communication method of the via node, the second downlink route construction unit 320 records the ID of the via node and the communication method with the via node that are contained in the uplink message in association with the ID of the child node in the via node information table 904.

[0294] When creating a downstream message for a child node, the multi-hop communication unit 340 of the parent device refers to the ID of the via node and the communication method of the via node listed in the via node information table 904, and creates a downstream message that includes the ID of the via node that exists on the route to the child device that sends the downstream message and the communication method with the via node.

[0295] Effect of embodiment 4 According to this embodiment 4, when sending a downstream message to a child device, the parent device (second collection device 20) can omit the process of creating a source routing header and a wireless method bitmap by tracing the combination of the destination ID and parent node listed in the downstream route table 901.

[0296] According to this fourth embodiment, the second collection device 20 can create a downstream message using the source routing header and wireless system bitmap recorded in the transit node information table 904 .

[0297] Another Example of the Fourth Embodiment In the present embodiment, the first handset 10x and the second handset 20x are used for explanation, but the third handset 30x also operates in the same manner as the first handset 10x.

[0298] In this embodiment, the IPv6 Hop-by-Hop extension header is used to add information when an upstream message is sent and forwarded, but any method can be used as long as it can notify the combination of the wireless system and the nodes passed through when an upstream message is sent and forwarded. For example, it may be added as an option header.

[0299] Furthermore, in this embodiment, a method is used in which two types of wireless systems, a first PHY / MAC and a second PHY / MAC, are represented by 0 or 1, but two or more types of wireless systems may be specified using multiple bits.

[0300] Furthermore, in the embodiment, an upstream message of the embodiment may be transmitted instead of the notification message (DAO message (DAO-2)) transmitted when the slave device completes the operation of joining the communication system 504. The second collection device 20 can create both the downstream route table 901 and the transit node information table 904 from the upstream message by the second downstream route construction unit 320.

[0301] Fifth Embodiment In the fourth embodiment, a method was described in which a slave device assigns an identifier indicating the slave device's ID and the communication method with the parent node when transmitting and transferring an upstream message, and the master device determines the downstream route and wireless method to be used for the downstream message by using the information in the upstream message.

[0302] In the fifth embodiment, differences from the fourth embodiment will be described. In the present embodiment, a method for determining a downstream route and a wireless method in the case where the ID of a slave device is assigned but the communication method is not assigned when an upstream message is transmitted and forwarded will be described.

[0303] FIG. 49 shows a network in which a first handset 10x, a second handset 20x, and a third handset 30x coexist in a communication system 504.

[0304] ●Operation of child device (only child device ID is assigned) Figure 54 shows a situation in which the nodes passed through on the way to the second collection device are added to the upstream message sent by the second child device 20r using the IPv6 Hop-by-Hop extension header.

[0305] The second slave device 20r writes the ID of the second slave device 20r (20r) in the Hop-by-Hop extension header by the multi-hop communication unit 340, and transmits the upstream message to the second slave device 20l, which is the parent node.

[0306] The second slave device 20l, which receives an upstream message from the second slave device 20r to the second collection device 20, writes the ID of the second slave device 20l: 20l in the Hop-by-Hop extension header using the multi-hop communication unit 340, and transmits the upstream message to the first slave device 10f, which is the parent node.

[0307] The first slave device 10f, which receives an upstream message from the second slave device 20l to the second collection device 20, writes the ID of the first slave device 10f: 10f in the Hop-by-Hop extension header using the first multi-hop communication unit 301, and transmits the upstream message to the second slave device 20b, which is the parent node.

[0308] The second slave device 20b, which receives an upstream message from the first slave device 10f to the second collection device 20, writes the ID of the second slave device 20b: 20b in the Hop-by-Hop extension header using the multi-hop communication unit 340 and transmits the upstream message to the parent node, the second collection device 20.

[0309] ●Operation of parent device (receiving only the child device ID) Figure 55 shows a situation in which the second collection device 20, having received an upstream message from the second child device 20r, registers the via node to be used for downstream traffic to the second child device 20r in the via node information table 905, which becomes part of the downstream route table.

[0310] When the second collection device 20 receives an upstream message from the second slave device 20r, the second downstream route construction unit 320 obtains the transit nodes from the Hop-by-Hop extension header and sorts them in reverse order to create a source routing header addressed to the second slave device 20r.

[0311] The second collection device 20 registers the source routing header and the wireless system bitmap information as a source routing header addressed to the second slave device 20r in the transit node information table 905 by the second downstream path construction unit 320. When transmitting a downstream message addressed to the second slave device 20r, if the second collection device 20r is registered in the transit node information table 905, the second collection device 20 uses the source routing header.

[0312] Furthermore, the multi-hop communication unit 340 of the second collection device 20 creates a wireless communication method bitmap by searching the downlink route table 901 for the destination ID written in the source routing header.

[0313] As described above, when transmitting or forwarding an upstream message addressed to a parent device, a child device in communication system 504 of embodiment 5 writes the node ID of the child device in the upstream message so that the order of the child devices can be determined. The parent device stores the node IDs written in the upstream message in a memory or storage device, and uses the stored node IDs to create a downstream message for the child device that sent the upstream message addressed to the parent device.

[0314] Summary of Fifth Embodiment The communication system 504 of the fifth embodiment has a feature that, when receiving information about an upstream route, the information about the upstream route is used to construct a downstream route.

[0315] When creating an upstream message addressed to the parent device and transmitting it to the parent device, the multi-hop communication unit 340 of the child device (child node) creates an upstream message including the ID of its own node and transmits it to the parent device.

[0316] When the multi-hop communication unit 340 of the child device (child node) receives an upstream message and transfers it to the parent device, it writes the ID of its own node in the upstream message and transmits it to the parent device.

[0317] When a child device (child node) sends or forwards an upstream message addressed to a parent device, it assigns its own ID to the upstream message. An upstream message addressed to a parent device notifies the parent device of the route (all nodes passed through) used in the message forwarding.

[0318] The second downstream route construction unit 320 of the parent device acquires the transit nodes attached to the upstream message received from the child node, sorts them in reverse order, and records them in the transit node information table 905 (source routing table).

[0319] When the second downlink route construction unit 320 of the parent device receives an upstream message from a child node containing the ID of a via node, it records the ID of the via node contained in the upstream message in association with the ID of the child node in the via node information table 905.

[0320] When transmitting a downstream message to a child node, the multi-hop communication unit 340 of the parent device searches the transit node information table 905 (source routing table) for the target node and acquires the route to be used.

[0321] When the multi-hop communication unit 340 of the parent device creates a downstream message for a child node, it refers to the ID of the transit node listed in the transit node information table 905 to identify the transit node that exists on the route to the child device to which the downstream message is sent.

[0322] The multi-hop communication unit 340 of the parent device acquires a wireless method from the downlink route table 901 using the IDs of the passed-through nodes on the route. The multi-hop communication unit 340 of the parent device refers to the downlink route table 901 to identify the communication method corresponding to the passed-through nodes on the route to the child device that sends the downlink message. The multi-hop communication unit 340 of the parent device creates a downlink message that includes the IDs of the passed-through nodes and the communication methods of the passed-through nodes.

[0323] Effect of embodiment 5 According to this embodiment 5, when sending a downstream message to a child device, the parent device (second collection device 20) can omit the process of creating a source routing header and a wireless method bitmap by tracing the combination of the destination ID and parent node listed in the downstream route table 901.

[0324] According to this fifth embodiment, the parent device (second collection device 20) can easily create a source routing header using the transit node information table 905.

[0325] Another Example of the Fifth Embodiment In the present embodiment, the first handset 10x and the second handset 20x are used for explanation, but the third handset 30x also operates in the same manner as the first handset 10x.

[0326] In addition, in this embodiment, the IPv6 Hop-by-Hop extension header is used to add information when sending and forwarding an upstream message, but any method can be used as long as it can notify the combination of the wireless method and the nodes passed through when sending and forwarding an upstream message, and for example, a method of adding it as an optional header can be used.

[0327] Furthermore, in this embodiment, a method is used in which two types of wireless systems, a first PHY / MAC and a second PHY / MAC, are represented by 0 or 1, but two or more types of wireless systems may be specified using multiple bits.

[0328] Furthermore, the passed node information table 905 may have an item for "wireless method bitmap" and may have the same format as the passed node information table 904. When the multi-hop communication unit 340 of the parent device identifies the communication method of the node by referring to the downlink route table 901, the multi-hop communication unit 340 writes the identified communication methods into the "wireless method bitmap" in order. As a result, a "wireless method bitmap" similar to the passed node information table 904 can be created.

[0329] Although multiple configurations have been described above, two or more of these configurations may be combined for implementation. Alternatively, one or a combination of two or more of these configurations may be partially implemented. Note that the present disclosure is not limited to the embodiments, and various modifications are possible as needed.

[0330] 10 First collection device, 20 Second collection device, 10x First child device, 20x Second child device, 30x Third child device, 100 First communication device, 101 Antenna, 102 First PHY, 103 First MAC, 111 Sensor device, 112 Actuator device, 113 Timekeeping calendar, 200 Second communication device, 201 Antenna, 202 Second PHY, 203 Second MAC, 300 Processor, 301 First multi-hop communication unit, 302 Second multi-hop communication unit, 310 First downlink path construction unit, 311 First uplink path construction unit, 320 Second downlink path construction unit, 321 Second uplink path construction unit, 330 Protocol determination unit, 340 Multi-hop communication unit, 350 Downlink path construction unit, 360 Uplink path construction unit, 370 Protocol conversion unit, 501 communication system, 502 communication system, 503 communication system, 504 communication system, 601 wireless link, 602 wireless link, 900 memory, 901 downstream route table, 902 route table, 903 rank table, 904 transit node information table, 905 transit node information table, 922 auxiliary storage device, 930 input interface, 940 output interface.

Claims

DEPCT6913 / 11 / 25681. A client unit connected to a wireless mesh network constructed based on the first-order value calculated by the first-order protocol, consists of: a communication device to receive one or more control messages indicating routing information, including node order information, from one or more neighboring nodes; a protocol decision unit to decide on the process to be executed according to the second-order protocol based on the first-order information; an ascending routing unit to calculate the second-order value using the first-order information of the second-order protocol based on the decision made by the protocol decision unit; to select one node from among one or more neighboring nodes based on one or more second-order values ​​as the primary node; and to record in the routing table the ID of the primary node and the second-order value calculated using the primary node's first-order information; and a multi-stage communication unit to generate alert messages to notify of the primary node ID recorded in the routing table and to transmit the alert message to the primary unit.2.The client unit, as defined in Claim 1, where the protocol decision unit decides to execute the protocol-first process based on the first-order information, and the ascending routing unit calculates the first-order value using the first-order information based on the first-order information according to the protocol-first decision unit, and records the first-order value calculated using the primary node's first-order information in the routing table.3 The client unit, as defined in Claim 1 or Claim 2, where the first-order information includes at least one of the first-order and second-order information; the first-order information includes the first-order value and the first minimum increment value; and the second-order information includes the second-order value and the second minimum increment value.4The client unit, as defined in claim 3, where the communication device receives from one node, is a first control message which includes the first-order information of the source node transmitting the control message, and a second control message which includes the second-order information of the source node transmitting the control message, and where the ascending path constructor includes the first ascending path constructor to calculate the first-order value based on the first-order information of the source node transmitting the control message, and the second ascending path constructor to calculate the second-order value based on the second-order information of the source node transmitting the control message.5The client unit, as defined in Claim 3, where the ascending routing constructor includes the protocol transformation unit to calculate the second-order value by applying weights to the entire connection interval from the master unit to the client unit when only the first control message, which includes the first-order information of the source node, is received from one node, and to calculate the first-order value based on the routing interval count when only the second control message, which includes the second-order information of the source node, is received from one node.

6. The client unit, as defined in any of Claim 1 through Claim 5, where, in calculating the second-order value, the ascending routing constructor calculates the second-order value by multiplying it by weights so that the difference in the second-order value occurs in the case of different communication systems being used.7.The client unit, as defined in any of Claims 1 through 6, where the routing information includes the number of consecutive paths in the second communication system in the path from the master unit, and when more than one node with the same second-order value exists, the upstream routing constructor selects the master node based on the number of consecutive paths.

8. The client unit, as defined in any of Claims 1 through 7, where the routing information includes the presence or absence of a node that can only communicate with the first communication system in the path from the master unit, and when more than one node with the same second-order value exists, the upstream routing constructor selects the master node based on the presence or absence of a node that can only communicate with the first communication system. 9.The client unit, as defined in any of Claims 1 through 8, where the routing information includes the type of the primary node or the primary node's communication system, and only when the primary and client nodes, respectively, correspond to the primary and secondary communication systems, the upstream routing constructor selects the secondary communication system as the communication system with the primary node, from the type of the primary node and the type of the client node, or by reference to the primary node's communication system and the client node's communication system, and records the communication system with the primary node in the routing table.

10. The client unit, as defined in Claim 9, where the multi-stage communication unit is indicated, in the notification message, the communication system with the primary node recorded in the routing table, and passes the notification message to the primary unit.11.The client unit, as defined in any of Claims 1 through 10, whereby the communication device receives a message downward which includes the ID of the node appearing in the path to the client unit to which the message is to be transmitted, and the communication system with the node, and the multistage communication unit connects to the ID of the node and the communication system with the node included in the message downward, specifies the ID of the client node and the communication system with the client node, and transfers the message downward to client node 12.A client unit, as defined in any of Claims 1 through 11, whereby when a multispan communicating unit creates and transmits an upstream message addressed to the master unit, the multispan communicating unit creates an upstream message indicating its own node ID and the system's communication with the master node, and transmits the upstream message to the master unit; and when a multispan communicating unit receives an upstream message and transmits it to the master unit, the multispan communicating unit indicates its own node ID and the system's communication with the master node in the upstream message, and transmits the upstream message to the master unit.13.A client unit as defined in any of Claims 1 through 11, whereby when a multispan communicating unit creates and transmits an upstream message addressed to the master unit, the multispan communicating unit creates an upstream message indicating its own node ID, and transmits the upstream message to the master unit; and when a multispan communicating unit receives an upstream message and transmits the upstream message to the master unit, the multispan communicating unit indicates its own node ID in the upstream message and transmits the upstream message to the master unit.14The master unit, connected to a wireless mesh network containing more than one client unit as a node, comprises: a communication device to receive notification messages informing client nodes of the master node's ID and the communication system with the master node; a downward routing unit to record, in the downward routing table, the master node's ID, the communication system with the master node included in the notification message, and the client node IDs in a related manner; and a multi-stage communication unit to reference the downward routing table, specifying one or more nodes appearing in the path to the client unit to which the downward message is transmitted, and to construct downward messages including the node ID and the communication system with node 15.The primary unit, as defined in claim 14, where the downward routing unit records the first and second information in the rank table, and the multi-stage communication unit constructs the first control message containing the first information and the second control message containing the second information, and transmits the first and second control messages to the adjacent node 16.The primary node, as defined in Claim 14 or Claim 15, whereby when a downward routing constructor receives an upward message indicating the traverse node ID and its communication system from a client node, the downward routing constructor records, in the traverse node information table, the traverse node ID and its communication system indicated in the upward message in relation to the client node ID. When a multistage communication unit constructs a downward message for a client node, the multistage communication unit refers to the traverse node ID and its communication system indicated in the traverse node information table and constructs a downward message that includes the traverse node ID and its communication system that appears in the path to the client unit to which the downward message is to be transmitted.17.The primary unit, as defined in Claim 14 or Claim 15, is that when a downward routing unit receives an upward message indicating the traverse node ID from a client node, the downward routing unit records, in the traverse node information table, the traverse node ID indicated in the upward message in relation to the client node ID. When a multistage communication unit constructs a downward message for a client node, the multistage communication unit identifies the traverse node appearing in the path to the client node by referencing the traverse node ID indicated in the traverse node information table, identifies the communication system of the corresponding traverse node appearing in the path to the client node by referencing the downward routing table, and constructs a downward message containing the traverse node ID and its communication system.18The communication system consists of: a master unit to transmit messages downward, which includes the node ID and the communication system with the node; and a client unit to receive messages downward, to specify the client node ID and the communication system with the client node by referencing the node ID and the communication system with the node included in the downward message; and to transfer the downward message to the client node.

19. The communication system as defined in claim 18, whereby when the client unit transmits and transfers messages upward addressed to the master unit, the client unit indicates the node ID and the client communication system in the upward message, and the master unit stores the node ID and the communication system indicated in the upward message, and constructs the downward message using the stored node ID and the communication system.20.A communication system as defined in claim 18, whereby when a client unit transmits and transfers an upward message addressed to a master unit, the client unit identifies the ID of the client node in the upward message, and the master unit stores the ID of the node identified in the upward message, and constructs a downward message using the stored node ID.

21. A communication system as defined in claim 18, where the master and client units are connected to a wireless mesh network capable of communicating using both first and second protocols, and the master and client units communicate using only the second protocol, terminating communication using the first protocol.22.The communication method of client units connected to a wireless mesh network constructed based on the first-order value calculated by the first-order protocol includes: by the communication device, receiving one or more control messages indicating routing information, including node order information, from one or more neighboring nodes; by the protocol decision unit, making decisions to execute the process according to the second-order protocol based on the first-order information; by the ascending routing unit, calculating the second-order value using the first-order information of the second-order protocol based on the decision made by the protocol decision unit, selecting one node from among one or more neighboring nodes as the principal node based on one or more second-order values, and recording the principal node ID and the second-order value calculated using the principal node's first-order information in the routing table; and by the multi-stage communication unit, creating and transmitting to the principal unit a notification message alerting the principal node ID recorded in the routing table.23The communication method of the master unit, which is connected to a wireless mesh network with more than one client unit as a node, consists of: by the communication device, receiving notification messages from the client nodes informing them of the master node's ID and the system communicating with the master node; by the downward routing unit, recording in the downward routing table the master node's ID and the system communicating with the master node, which are included in the notification message, and the client node IDs in a related manner; and by the multi-stage communication unit, referencing the downward routing table, specifying one or more nodes appearing in the path to the client unit to which the client transmits the downward message, and creating a downward message that includes the node's ID and the system communicating with the node.The program enables a client unit connected to a wireless mesh network constructed based on a first-order value calculated by the first-order protocol. The communication device receives one or more control messages indicating routing information, including node order information, from one or more neighboring nodes, in order to perform the following actions: a protocol decision process to decide whether to proceed with the second-order process based on the order information; an ascending routing process to calculate the second-order value using the second-order information based on the decision results from the decision process; to select one node from among one or more neighboring nodes based on one or more second-order values ​​as the primary node; and to record the primary node ID and the second-order value calculated using the primary node's order information in the routing table; and a multi-stage communication process to create and transmit to the primary unit an alert message notifying them of the primary node ID recorded in the routing table.25The program enables the master unit, connected to a wireless mesh network containing more than one client unit as a node, to perform communication processes. This process receives notification messages from client nodes informing them of the master node's ID and the system communicating with it. The master unit, receiving these notification messages, then executes the following processes: a downward routing process to record in the downward routing table the master node ID and the system communicating with the master node (included in the notification message), and the client node IDs in a related manner; and a multi-stage communication process to reference the upward routing table, specifying one or more nodes in the path to the client unit to which the downward message is transmitted, and to construct an upward message containing the node ID and the system communicating with the node.

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