Child unit, parent unit, communication system, communication method, and program

Abstract

The child device connected to the wireless mesh network includes a second communication device (200) that receives a control message from a neighboring node, a protocol determination unit (330) that determines whether the control message is to be processed by a first protocol or a second protocol, and an upstream route construction unit (360) that uses route information included in the control message to calculate a first rank value based on the first protocol and a second rank value based on the second protocol, selects a parent node from the neighboring nodes based on the first rank value and the second rank value, and records the ID of the parent node in a route table (902).

Description

[Technical field]

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

[0002] Wireless mesh networks are used for sensor networks to collect environmental information and for collecting electricity meter readings using smart meters. In a wireless mesh network, a data collector and a slave unit autonomously construct a network using wireless devices. In the future, it is possible that the communication methods used by existing smart meters will no longer be sufficient, and that next-generation smart meters with communication methods different from the current ones may become necessary.

[0003] As a routing protocol for wireless mesh networks, RPL (Routing Protocol for Low-Power and Lossy Networks) described in Non-Patent Document 1 is defined as an Internet standard. In wireless mesh networks using RPL, there is a demand to realize faster data collection cycles and broader communication bandwidth while maintaining the data collection function of existing 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 a wireless communication method in accordance with the wireless communication method. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6752383 [Non-patent literature]

[0005] [Non-Patent Document 1] 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> Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is 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. [Means for solving the problem]

[0007] A slave device according to one aspect of the present disclosure includes: A slave device connected to a wireless mesh network constructed based on a first rank value calculated by a first protocol, A communication device that receives one or more control messages from one or more neighboring nodes, the control messages including route information including rank information of the node; 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 a 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 an ID of the parent node and the second rank value calculated using the rank information of the parent node in a route table; a multi-hop communication unit that creates a notification message for notifying the ID of the parent node recorded in the route table and transmits the notification message to a parent device; The present invention is characterized by comprising: Effect of the Invention

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

[0009] [Figure 1] FIG. 5 is a configuration diagram of a communication system 501 according to the first embodiment. [Diagram 2] 1 is a configuration diagram of a first collection device 10 according to a first embodiment. [Diagram 3] FIG. 2 is a configuration diagram of a first slave unit 10x according to the first embodiment. [Figure 4] FIG. 5 is a configuration diagram of a communication system 502 according to the first embodiment. [Diagram 5] FIG. 2 is a configuration diagram of a second collection device 20 according to the first embodiment. [Figure 6] FIG. 2 is a configuration diagram of a second slave unit 20x according to the first embodiment. [Figure 7] FIG. 11 is a configuration diagram of a third slave unit 30x according to the first embodiment. [Figure 8] FIG. 11 is a diagram showing a sequence when a first handset 10a, a second handset 20d, and a third handset 30e join in the first embodiment. [Figure 9] FIG. 9 is a diagram showing a rank table 903 according to the first embodiment. [Figure 10] 13 is a diagram showing the RPL rank 1 held in the route table 902 of the first slave unit 10a in the first embodiment and the ID of a selected parent node. FIG. [Figure 11] 9 is a diagram illustrating a downstream route table 901 managed by the second collection device 20 in the first embodiment. FIG. [Figure 12]13 is a diagram showing a wireless system bitmap and a source routing header added to a downstream message addressed to a first slave unit 10a in a second collection device 20 in the first embodiment. FIG. [Figure 13] 9 is a diagram showing a route table 902 held by the second slave device 20d in the first embodiment. FIG. [Figure 14] 9 is a diagram illustrating a downstream route table 901 managed by the second collection device 20 in the first embodiment. FIG. [Figure 15] 13 is a diagram showing a wireless system bitmap and a source routing header added to a downstream message addressed to a second slave unit 20d in the second collection device 20 in the first embodiment. FIG. [Figure 16] 13 is a diagram showing a route table 902 held by the third slave device 30e in the first embodiment. FIG. [Figure 17] 9 is a diagram illustrating a downstream route table 901 managed by the second collection device 20 in the first embodiment. FIG. [Figure 18] 13 is a diagram showing a wireless system bitmap and a source routing header added to a downstream message addressed to a third slave device 30e in the second collection device 20 of the first embodiment. FIG. [Figure 19] FIG. 13 is a diagram showing a sequence when a second handset 20b, a first handset 10f, a second handset 20g, and a third handset 30h join in the first embodiment. [Figure 20] 9 is a diagram showing a route table 902 held by the second slave device 20b in the first embodiment. FIG. [Figure 21] 9 is a diagram illustrating a downstream route table 901 managed by the second collection device 20 in the first embodiment. FIG. [Figure 22] 13 is a diagram showing a wireless system bitmap and a source routing header added to a downstream message addressed to a second slave unit 20b in the second collection device 20 in the first embodiment. FIG. [Figure 23] 13 is a diagram showing the RPL rank 1 held in the route table 902 of the first slave device 10f in the first embodiment and the ID of a selected parent node. FIG. [Figure 24]9 is a diagram illustrating a downstream route table 901 managed by the second collection device 20 in the first embodiment. FIG. [Diagram 25] 13 is a diagram showing a wireless system bitmap and a source routing header added to a downstream message addressed to a first slave terminal 10f in the second collection device 20 of the first embodiment. FIG. [Figure 26] 9 is a diagram showing a route table 902 held by the second slave device 20g in the first embodiment. FIG. [Figure 27] 9 is a diagram illustrating a downstream route table 901 managed by the second collection device 20 in the first embodiment. FIG. [Figure 28] 13 is a diagram showing a wireless system bitmap and a source routing header added to a downstream message addressed to a second slave device 20g in the second collection device 20 of the first embodiment. FIG. [Figure 29] 13 is a diagram showing a route table 902 held by a third slave device 30h in the first embodiment. FIG. [Diagram 30] 9 is a diagram illustrating a downstream route table 901 managed by the second collection device 20 in the first embodiment. FIG. [Diagram 31] 13 is a diagram showing a wireless system bitmap and a source routing header added to a downstream message addressed to a third slave unit 30h in the second collection device 20 of the first embodiment. FIG. [Diagram 32] FIG. 13 is a diagram showing a sequence when a third handset 30c and a second handset 20i join in the first embodiment. [Diagram 33] 13 is a diagram showing a route table 902 held by the third slave device 30c in the first embodiment. FIG. [Diagram 34] 9 is a diagram illustrating a downstream route table 901 managed by the second collection device 20 in the first embodiment. FIG. [Diagram 35] 13 is a diagram showing a wireless system bitmap and a source routing header added to a downstream message addressed to a third slave unit 30c in the second collection device 20 of the first embodiment. FIG. [Diagram 36] 9 is a diagram showing a route table 902 held by the second slave unit 20i in the first embodiment. FIG. [Figure 37] 9 is a diagram illustrating a downstream route table 901 managed by the second collection device 20 in the first embodiment. FIG. [Figure 38] 13 is a diagram showing a wireless system bitmap and a source routing header added to a downstream message addressed to a second slave unit 20i in a second collection device 20 in the first embodiment. FIG. [Figure 39] 13 is a flowchart of parent node selection in the second child device and the third child device in the second embodiment. [Diagram 40] 13 is a diagram showing a situation in which a second slave device 20d joins a wireless mesh network configured with a second collection device 20, a first slave device 10a, a second slave device 20b, and a second slave device 20c according to the second embodiment. FIG. [Diagram 41] 13 is a diagram showing a situation in which a second slave device 20d joins a wireless mesh network configured with a second collection device 20 of the second embodiment and a first slave device 10a, a second slave device 20b, and a third slave device 30c. FIG. [Diagram 42] 13 is a diagram showing a situation in which a second slave device 20d joins a wireless mesh network configured with a second collection device 20, a first slave device 10a, and second slave devices 20b, 20c, and 20e according to the second embodiment. FIG. [Diagram 43] 13 is a diagram showing a situation in which a second slave device 20d joins a wireless mesh network configured with a second collection device 20, a first slave device 10a, and second slave devices 20b, 20c, and 20e according to the second embodiment. FIG. [Diagram 44] 13 is a diagram showing a situation in which a second slave device 20d joins a wireless mesh network configured with a second collection device 20, a first slave device 10a, and third slave devices 30b, 30c, and 30e according to the second embodiment. FIG. [Diagram 45] 13 is a diagram showing a situation in which a second slave device 20d joins a wireless mesh network configured with a second collection device 20, a first slave device 10a, and third slave devices 30b, 30c, and 30e according to the second embodiment. FIG. [Diagram 46]FIG. 13 is a diagram showing 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 according to the second embodiment. [Figure 47] FIG. 11 is a diagram showing a state in which a first handset 10x is replaced with a second handset 20x and a third handset 30x in a communication system 503 of the third embodiment. [Figure 48] FIG. 48 is a diagram showing 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 of the third embodiment. [Figure 49] FIG. 11 is a configuration diagram of a communication system 504 according to the fourth and fifth embodiments. [Figure 50] 13 is a diagram showing a Hop-by-Hop extension header that a slave device of the fourth embodiment adds to an upstream message. FIG. [Figure 51] 13 is a diagram showing a wireless system bitmap and a source routing header added to a downstream message addressed to a second slave unit 20b in a second collection device 20 of the fourth embodiment. FIG. [Figure 52] 13 is a diagram showing a Hop-by-Hop extension header that a slave device of the fourth embodiment adds to an upstream message. FIG. [Figure 53] 13 is a diagram showing a wireless system bitmap and a source routing header added to a downstream message addressed to a second slave device 20r in a second collection device 20 according to the fourth embodiment. FIG. [Figure 54] 13 is a diagram showing a Hop-by-Hop extension header that a slave device of embodiment 5 adds to an upstream message. FIG. [Figure 55] 13 is a diagram showing a wireless system bitmap and a source routing header added to a downstream message addressed to a second slave device 20r in a second collection device 20 according to a fifth embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0011] ●Terminology explanation node: Parent unit and child unit. Neighboring nodes: A node that is located within a communication range where radio waves can reach and is already part of the network and capable of communication. Parent unit: A radio unit of a root node corresponds to the first collecting device 10 and the second collecting device 20. Child unit: Wireless devices of the node, which correspond to the first slave unit 10x, the second slave unit 20x, and the third slave unit 30x. Rank Value: A value that expresses the relative position (distance) from the parent device to the child device. A route quality value that indicates the route quality from the collection device to the child device. The value increases as the number of hops from the parent device on the route from the parent device to the child device increases. It corresponds to the RPL rank. 1st Rank Value: Rank value calculated based on the first protocol. Equivalent to RPL rank 1. In this specification, the first rank value initially set in the parent device is 128. Second Rank Value: Rank value calculated based on the second protocol. Equivalent to RPL rank 2. In this specification, the second rank value initially set in the parent unit is 32. MinimumHopRankIncrease: The minimum increase in rank from a parent node to a child node. This value is stored in advance in each node. MinimumHopRankIncrease-1: First minimum increment value used in calculating the first rank value. In this specification, 128 is used as the first minimum increment value for using a low transmission rate wireless system. MinimumHopRankIncrease-2: A second minimum increment value used in calculating the second rank value. In this specification, 32 is used as the second minimum increment value for using a high transmission rate wireless system. The first minimum increment value (128) is weighted four times as much as the second minimum increment value (32). Control messages: A message sent by a neighboring node to invite it to join as a child node. A message that contains route information for building a route. Corresponds to DIO-1 and DIO-2. 1st rank information: Information of the sending node for calculating the first rank value. The first rank value of the sending node described in the control message and MinimumHopRankIncrease-1. Second rank information: Information of the sending node for calculating the second rank value. The second rank value of the sending node described in the control message and MinimumHopRankIncrease-2. First control message: A control message including the first rank value of the node that sent the control message and MinimumHopRankIncrease-1. Equivalent to DIO-1. Second control message: A control message containing the second rank value of the node that sent the control message and MinimumHopRankIncrease-2. Equivalent to DIO-2. protocol: A communication protocol or an algorithm for implementing a communication protocol executed by a parent or child device. First Protocol: A protocol that calculates a first rank value (RPL rank 1) using the first rank values ​​(RPL rank 1) of neighboring nodes and selects a parent device with the smallest first rank value (RPL rank 1).Furthermore, a protocol that notifies only the first rank value (RPL rank 1) to neighboring nodes.A protocol implemented by the 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 unit based on the second rank value (RPL rank 2).Further, a protocol that selects a communication method with the parent unit.Further, 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 unit 20x and the third child unit 30x. Upstream route construction section: A module that selects one node from among one or more neighboring nodes as a parent node and selects a communication method with the parent node, the module including a first upstream path construction unit and a second upstream path construction unit. First upstream path construction section: A route construction unit corresponding to the first protocol, which is a module for calculating a first rank value based on the first rank information of a source node. Second upstream path construction section: A route construction unit corresponding to the second protocol, which is a module for calculating a second rank value based on the second rank information of the source node. Multi-hop communication part: A communication unit implementing the protocol, the communication unit 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 part: A communications 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. If the communication speed, modulation method, or transmission output method is different, the communication method will be different. First communication method: A communication method used by the first PHY 102 and the first MAC 103. It corresponds to the first PHY / MAC. A specific example is a low transmission rate wireless method. Second communication method: A communication method used by the second PHY 202 and the second MAC 203. It corresponds to the second PHY / MAC. A specific example is a high-transmission-rate wireless method. Node ID: An identifier for identifying a wireless device, such as a MAC address. In this specification, symbols such as 10a, 10b, etc. are used as IDs.

[0012] Embodiment 1 In this first embodiment, a communication system 501 will be described in which communication devices (child devices) implemented in a plurality of smart meters construct a wireless mesh network using one communication method for communication paths to a collection device (parent device). A case will be described in which communication devices constructing the multi-hop network shown in communication system 501 are randomly replaced with new communication devices implementing a new communication method in communication system 502. In particular, a case will be described in which a multi-hop network is constructed that makes use of the advantages of the new communication method while maintaining the multi-hop communication of the existing communication devices.

[0013] FIG. 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 a plurality of first slave devices 10a, 10b, ..., 10i via wireless links 601. Hereinafter, the reference numerals 10a, 10b, ..., 10i may be simply written 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 the first protocol.

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

[0015] FIG. 2 is a configuration diagram of the first collection device 10. As shown in FIG. The first collection device 10 has a first communication device 100 for communicating with the first child 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" is 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 is part of the data link layer in the OSI layer model. "MAC" is an abbreviation for Medium Access Control. Here, "MAC" refers to a circuit (data link layer device) that implements the functions of a communication protocol that is part of the data link layer.

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

[0019] FIG. 3 is a diagram showing the configuration of the first slave unit 10x. The first slave 10x has a first communication device 100 for communicating with the first collection device 10 and other first slaves, and an antenna 101 for receiving radio signals. The first slave unit 10x includes a first communication device 100, a first PHY 102 that digitizes a wireless signal, and a first MAC 103 that performs media access control. The first slave unit 10x includes a sensor device 111 for sensing, an actuator device 112 operated from the slave unit, and a timekeeping calendar 113 for acquiring the date and time. The first slave device 10 x includes a processor 300 having a first multi-hop communication unit 301 and a first uplink route construction unit 311 . The first slave device 10x includes a memory 900 and an auxiliary storage device 922 for recording the next hop node to the first collection device 10 selected by route construction and various option settings. The first handset 10 x includes an input interface 930 and an output interface 940 .

[0020] The operation of the first slave device 10x when constructing a route for multi-hop communication will be described. The first multi-hop communication unit 301 transmits a DIS (DODAG Information Solicitation) message requesting the establishment of a route for multi-hop communication at an arbitrary timing. The first multi-hop communication unit 301 determines whether or not a DIO (DODAG Information Object) message has been received from a neighboring node after a certain delay. When the first multi-hop communication unit 301 receives a DIO message, which is a route establishment response message in response to the DIS message, from the first slave unit during a certain period of time, the first multi-hop communication unit 301 passes the DIO message to the first upstream route establishment unit 311 .

[0021] The first upstream path establishment unit 311 calculates the rank value of the first slave unit 10x from the information included in the DIO message. The first upstream route construction unit 311 selects the node for which the smallest rank value has been calculated as the parent node from among the neighboring nodes, and records the parent node's ID and rank value in association with each other. The first multi-hop communication unit 301 notifies the first communication device 100 of the ID of the parent node. The first communication device 100 records a pair of the ID of the parent node 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 called the first rank value. The communication method used by the first PHY 102 and the first MAC 103 is called a first communication method.

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

[0024] FIG. 5 is a diagram showing the configuration of the second collection device 20. As shown in FIG. The second collection device 20 has a second communication device 200 for communicating with the first handset 10x, the second handset 20x, and the third handset 30x, and an antenna 201 for receiving wireless signals. The second collection device 20 includes in the second communication device 200 a first PHY 102 for digitizing a wireless signal of a wireless link 601 and a first MAC 103 for performing media access control. The second collection device 20 has a second PHY 202 that digitizes a wireless signal 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 collection device 20 includes 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 collection device 20 includes a processor 300 having a protocol determination unit 330 that determines whether the communication is a first multi-hop communication or a second multi-hop communication. The multi-hop communication unit 340 includes a first multi-hop communication unit 301 and a second multi-hop communication unit 302 . The downstream path construction unit 350 includes a second downstream path construction unit 320 . The second collection device 20 implements the second protocol by means of the protocol determination unit 330, the multi-hop communication unit 340, and the downstream route construction unit 350.

[0025] FIG. 6 is a diagram showing the configuration of the second slave unit 20x. The second slave 20x has an antenna 201 for receiving radio signals in a second collecting device and a second communication device 200 for communicating with the first slave 10x, the second slave 20x and the third slave 30x. The second slave unit 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 20 x has a processor 300 including a first multi-hop communication unit 301 , a first upstream path establishment unit 311 , a second multi-hop communication unit 302 , and a second upstream path establishment unit 321 . The second slave unit 20x has, in the processor 300, a protocol determination unit 330 that determines between the first multi-hop communication and the second multi-hop communication, and a protocol conversion unit 370 that converts between the RPL rank value used in the first multi-hop communication and the RPL rank value used in the second multi-hop communication. The multi-hop communication unit 340 includes a first multi-hop communication unit 301 and a second multi-hop communication unit 302 . The upstream path construction unit 360 includes a first upstream path construction unit 311 , a second upstream path construction unit 321 , and a protocol conversion unit 370 . The second slave device 20x implements the second protocol by means of the protocol determination unit 330, the multi-hop communication unit 340, and the upstream route construction unit 360.

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

[0027] The meaning of each radio is explained below. The first collection device 10 and the first child device 10x are existing wireless devices to be replaced. The second collecting device 20 and the second child device 20x are new replacement wireless devices. The third slave unit 30x uses the same hardware as the first slave unit 10x as is, but has an upgraded software version that enables it to process 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 Protocol 1: Yes Second Protocol Not possible 1st rank value RPL rank 1 Remember Second rank value RPL rank 2 Do not remember MinimumHopRankIncrease-1 Pre-stored MinimumHopRankIncrease-2 Don't remember Control message DIO-1 can be created Control message DIO-2 cannot be created Notification message DAO-1 Processing possible Announcement message DAO-2 Processed as DAO-1

[0029] Second collection device 20 First communication method: Possible Second communication method: Possible Protocol 1: Yes Second Protocol: Yes The first rank value of the own node is stored (this value is known to the second child device 20x and the third child device 30x) The second rank value of the own node is stored (this value is known to the second child device 20x and the third child device 30x) MinimumHopRankIncrease-1: Prestored (known value for the second handset 20x and the third handset 30x) MinimumHopRankIncrease-2: Prestored (known value for the second handset 20x and the third handset 30x) Control message DIO-1 can be created Control message DIO-2 can be created Notification message DAO-1 Processing possible Notification message DAO-2 Processing possible

[0030] First handset 10x First communication method: Possible Second communication method Not possible Protocol 1: Yes Second Protocol Not possible Remember the first rank value of your node Second rank value of own node Not memorized MinimumHopRankIncrease-1: Pre-stored MinimumHopRankIncrease-2:Don't remember Control message DIO-1 can be created Control message DIO-2 cannot be created Announcement message DAO-1 can be created Notification message DAO-2 cannot be created

[0031] Second handset 20x First communication method: Possible Second communication method: Possible Protocol 1: Yes Second Protocol: Yes Remember the first rank value of your node Remember the second rank value of your node MinimumHopRankIncrease-1: Pre-stored MinimumHopRankIncrease-2: Pre-stored 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 handset 30x First communication method: Possible Second communication method Not possible Protocol 1: Yes Second Protocol: Yes Remember the first rank value of your node Remember the second rank value of your node MinimumHopRankIncrease-1: Pre-stored MinimumHopRankIncrease-2: Pre-stored Control message DIO-1 can be created Control message DIO-2 can be created Announcement message DAO-1 can be created Notification message DAO-2 Processing possible

[0033] ● Method and program explanation The "parts" of the first multi-hop communication unit 301, the first downlink path establishment unit 310, the first uplink path establishment unit 311, the second multi-hop communication unit 302, the second downlink path establishment unit 320, the second uplink path establishment unit 321, and the protocol conversion unit 370 may be read as "processing," "procedure," or "step." Also, the "processing" of the first multi-hop communication unit 301, the first downlink path establishment unit 310, the first uplink path establishment unit 311, the second multi-hop communication unit 302, the second downlink path establishment unit 320, the second uplink path establishment unit 321, and the protocol conversion unit 370 may be read as "program," "program product," or "computer-readable recording medium on which a program is recorded." The communication program causes the computer to execute each of the processes, procedures, or steps, where the "part" of each of the above parts is interpreted as a "process," "procedure," or "step." The communication method is carried out by each device in the communication system executing a communication program. The communication program may be provided by being stored in a computer-readable non-volatile recording medium, or may be provided as a program product.

[0034] 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 a single electronic circuit or may be distributed across multiple electronic circuits. As another variant, some 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 electronic circuits, and the remaining functions may be realized by software. As 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. In other words, the functions of the first multi-hop communication unit 301, the first downlink path establishment unit 310, the first uplink path establishment unit 311, the second multi-hop communication unit 302, the second downlink path establishment unit 320, the second uplink path establishment 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 handset 10a, the second handset 20d, and the third handset 30e join the communication system 502 in FIG. When the first slave unit 10a joins the second collection device The operation of the first handset 10a joining 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 .

[0037] The second collection device 20 that has received the DIS-1 from the first child device 10a 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 the DIS-1 by broadcasting the DIO-2 in the first MAC 103 and the first PHY 102. *RPL rank of own node is 2 *MinimumHopRankIncrease-2 used in the second multi-hop communication *Wireless systems that the node itself can support (wireless system using a first PHY 102 and a first MAC 103 (hereinafter referred to as a first PHY / MAC), and wireless system using a second PHY 202 and a second MAC 203 (hereinafter referred to as a second PHY / MAC)) *Device type of the own node * 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 path information in DIO-2 and broadcasts it. *RPL rank 2 of own node = 32 *MinimumHopRankIncrease-2=32 *Radio method = 2nd PHY / MAC *Device type = Secondary collection device *Continuous high transmission rate = 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 broadcasts DIO-1 in the first MAC 103 and the first PHY 102 to respond to DIS-1. *RPL rank of own node is 1 *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. *RPL Rank 1=128 *MinimumHopRankIncrease-1=128

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

[0042] The first upstream path construction unit 311 of the first slave unit 10a The RPL rank of the second collection device 20 described in the DIO-1 is 1; MinimumHopRankIncrease-1 described in the DIO-1; a metric indicating a state between the wireless link between the second communication device 200 of the second collection device 20 and the first communication device 100 of the first child device 10a, the metric being acquired when receiving the DIO-1; From this, the RPL rank 1 of the own node is calculated.

[0043] If the metric representing the state between the wireless links is 0, the first slave unit 10a is connected to the DIO-1 of the second collection device 20. RPL rank 1 = 128, MinimumHopRankIncrease-1=128 and Calculate the RPL rank 1 of the own node = 256 from this.

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

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

[0046] The second collection device 20 determines by 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 route construction unit 320. Since the type of wireless link (wireless system) is not described in DAO-1, ​​the second downlink path establishment unit 320 determines the wireless system to be the first PHY / MAC. The second downlink route construction unit 320 records in the downlink route table 901 the parent node ID selected by the first child device 10a described in DAO-1 and the type of wireless link (wireless method) used by the parent node selected by the first child device 10a to hop to the first child device 10a.

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

[0048] FIG. 12 shows a wireless system bitmap and a source routing header that are added to a downstream message addressed to the first slave unit 10a in the second collection device 20. In FIG. The wireless system bitmap specifies the wireless system from the first bit to the first hop, second hop, etc., using a reserved area that is ignored by the first child device. If the wireless system is the first PHY / MAC, the bit value is 0, and if it is the second PHY / MAC, the bit value is 1. The source routing header lists the node IDs of the nodes through which the message will travel on its way to its destination in the order of hops. When the first slave unit 10a receives a downstream message in which the wireless system bitmap and source routing header are described, 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 An operation for the second handset 20d to join the communication system 502 will be described. The second slave device 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 through the first MAC 103 and the first PHY .

[0050] The first slave device 10a that has received the DIS-1 from the second slave device 20d describes 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 1 of own node *MinimumHopRankIncrease-1 used in the first multi-hop communication

[0051] The first slave unit 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 unit 20d, which has received DIO-1 from the first slave unit 10a, determines in the protocol determination unit 330 that the first upstream path construction unit 311 should process the DIO-1. The first upstream route constructor 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 unit 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 *Minimum HopRank Increase-1 listed in the relevant DIO-1

[0053] If the metric indicating the state between the wireless links is 0, the second slave unit 20d receives the metric described in the DIO-1 of the first slave unit 10a. RPL rank 1 = 256, MinimumHopRankIncrease-1=128 and The RPL rank of the local node is calculated as 1=384.

[0054] Furthermore, the second slave unit 20d performs the following by the protocol conversion unit 370: The information listed in DIO-1 and The parameter MinimumHopRankIncrease-2=32 is stored in advance, Metrics that represent the state of wireless links Calculate RPL rank 2 from 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. Assume 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 child device 20d is calculated based on the information written in the LQL. Assume 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 child device." A weighting is applied to all hops based on the low transmission rate, 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) × weight of low transmission rate (= 2) + metric (= 0)) = 160

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

[0057] FIG. 13 shows a route table 902 held by the second child device 20d when the first child device 10a is selected as a parent node. The second child device 20d manages RPL rank 1, RPL rank 2, the ID of the parent node selected by RPL rank 2, the type of parent node, the wireless method 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 child device on the path, and the presence or absence of a first child device on the path.

[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 *Parent node type = 1st child *Wireless method with parent node = 1st PHY / MAC *Continuous high transmission rate = 0 (The details are unknown because the parent node is the first child device, but the default is set to 0) * Third child unit = No (The details are unknown because the parent node is the first child unit, but the default is set to No) *First child unit existence = Yes (because the parent node is the first child unit)

[0059] Furthermore, the second child device 20d creates, in the second multi-hop communication unit 302, 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. The second slave device 20d transmits the DAO-2 to the second collecting device 20 via the first slave device 10a that it 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 route construction unit 320. The second downstream path construction unit 320 records in the downstream path table 901 the parent node ID selected by the second slave device 20d written in DAO-2 and the wireless system for the parent node.

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

[0062] FIG. 15 shows a wireless system bitmap and a source routing header that are added to a downstream message addressed to the second slave unit 20d in the second collection device 20. In FIG. The wireless system bitmap specifies the wireless system from the first bit to the first hop, second hop, etc., using a reserved area that is ignored by the first child device. If the wireless system is the first PHY / MAC, the bit value is 0, and if it is the second PHY / MAC, the bit value is 1. The source routing header lists the node IDs of the nodes through which the message will travel on its way to its destination in the order of hops. 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 slave device 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 through the first MAC 103 and the first PHY .

[0064] The first slave device 10a that 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 own node is 1 *MinimumHopRankIncrease-1 used in the first multi-hop communication

[0065] The first slave unit 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 unit 30e, which has received the DIO-1 from the first slave unit 10a, determines in the protocol determination unit 330 that the DIO-1 should be processed in the first upstream path construction unit 311. The first upstream route constructor 311 of the third slave device 30e calculates the RPL rank 1 of its own node from the following information. *RPL rank 1 of the first slave unit 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 first communication device 100 of the third slave device 30e, acquired when receiving the DIO-1 *Minimum HopRank Increase-1 listed in the relevant DIO-1

[0067] If the metric indicating the state between the wireless links is 0, the third slave unit 30e receives the metric described in the DIO-1 of the first slave unit 10a. RPL rank 1 = 256, MinimumHopRankIncrease-1=128, The RPL rank of the local node is calculated as 1=384.

[0068] Furthermore, the third slave unit 30e, by the protocol conversion unit 370, The information listed in DIO-1 and The parameter MinimumHopRankIncrease-2=32 is stored in advance, Metrics that represent the state of wireless links Calculate RPL rank 2 from 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. In the communication system 502, it is assumed that LQL (Link Quality Level) is adopted as a metric representing the state between wireless links. The number of hops from the second collection device 20 to the third child device 30e is calculated based on 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 child device." A weighting is applied to all hops based on the low transmission rate, 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) × weight of low transmission rate (= 2) + metric (= 0)) = 160

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

[0071] FIG. 16 shows a route table 902 held by the third child device 30e when the first child device 10a is selected as a parent node. The third child device 30e manages RPL rank 1, RPL rank 2, the ID of the parent node selected by RPL rank 2, the type of parent node, the wireless method 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 child device on the path, and the presence or absence of a first child device on the path.

[0072] The route table 902 of the third slave unit 30e is as follows: *RPL Rank 1=384 *RPL Rank 2=160 *Parent node ID=10a *Parent node type = 1st child *Wireless method with parent node = 1st PHY / MAC *Continuous high transmission rate = 0 (The details are unknown because the parent node is the first child device, but the default is set to 0) * Third child unit = No (The details are unknown because the parent node is the first child unit, but the default is set to No) *First child unit existence = Yes (because the parent node is the first child unit)

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

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

[0075] FIG. 17 shows the downstream route table 901 managed by the second collection device 20. When the second collecting device 20 transmits a downstream message addressed to the third child device 30e, the second collecting device 20 confirms the nodes to be passed from the second collecting device 20 to the third child device 30e and the designated wireless method by tracing the downstream route table 901. That is, the downstream message from the second collecting device 20 to the third child device 30e is transmitted to the first child device 10a using the first PHY / MAC and to the third child device 30e using the second PHY / MAC.

[0076] FIG. 18 shows a wireless system bitmap and a source routing header that are added to a downstream message addressed to the third slave unit 30e in the second collection device 20. In FIG. The wireless system bitmap specifies the wireless system from the first bit to the first hop, second hop, etc., using a reserved area that is ignored by the first child device. If the wireless system is the first PHY / MAC, the bit value is 0, and if it is the second PHY / MAC, the bit value is 1. The source routing header lists the node IDs of the nodes through which the message will travel on its way to its destination in the order of hops.

[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] FIG. 19 shows a sequence in the case where the second handset 20b, the first handset 10f, the second handset 20g, and the third handset 30h join the communication system 502 in FIG. When the second slave device 20b joins the second collection device 20 The operation of the second handset 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 through the first MAC 103 and the first PHY .

[0079] The second collection device 20 that has received DIS-1 from the second child device 20b 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 of own node is 2 *MinimumHopRankIncrease-2 used in the second multi-hop communication *Wireless system that the node can support (first PHY 102 and first MAC 103, second PHY 202 and second MAC 203) *Device type of the own node * 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 path information in DIO-2 and broadcasts it. *RPL Rank 2=32 *MinimumHopRankIncrease-2=32 *Radio method = 2nd PHY / MAC *Device type = Secondary 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 broadcasts DIO-1 in the first MAC 103 and the first PHY 102 to respond to DIS-1. *RPL rank 1 of 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. *RPL Rank 1=128 *MinimumHopRankIncrease-1=128

[0083] The second child device 20b, which receives DIO-2 and DIO-1 from the second collection device 20, determines by its protocol determination unit 330 to process the DIO-2 in the second multi-hop communication unit 302 and the second upstream path construction unit 321, and to process the 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 The RPL rank 2 of the second collection device 20 described in the DIO-2; MinimumHopRankIncrease-2 described in the DIO-2; a metric indicating a state between the wireless link between the second communication device 200 of the second collection device 20 and the second communication device 200 of the second child device 20b, the metric being acquired when receiving the DIO-2; Calculate the RPL rank 2 of the own node from this.

[0085] The second slave device 20b calculates the RPL rank 2=64 from the information recorded in the DIO-2 of the second collection device 20 and the metric of the wireless link as follows. RPL rank 2 = (RPL rank 2 of the second collector 20 (= 32) + Minimum HopRank Increase - 2 (= 32) + metric (= 0)) = 64

[0086] The first upstream path construction unit 311 of the second slave device 20b The RPL rank of the second collection device 20 described in the DIO-1 is 1; MinimumHopRankIncrease-1 described in the DIO-1; a metric indicating a state between the wireless link between the second communication device 200 of the second collection device 20 and the second communication device 200 of the second child device 20b, the metric being acquired when receiving the DIO-1; From this, the RPL rank 1 of the own node is calculated.

[0087] If the metric representing the state between the wireless links is 0, the second child device 20b is the second child device 20b that is described in the DIO-1 of the second collection device 20. RPL rank 1 = 128, MinimumHopRankIncrease-1=128 and Calculate the RPL rank 1 of the own node = 256 from this.

[0088] The second slave unit 20b may not be able to receive DIO-1 due to a communication failure. If the second slave unit 20b can only receive DIO-2, the protocol conversion unit 370 calculates the number of hops from the information described in DIO-2 and calculates the RPL rank 1.

[0089] The operation of the protocol conversion unit 370 is as follows. In the communication system 502, it is assumed that LQL (Link Quality Level) is adopted as a metric representing the state between wireless links. The number of hops from the second collection device 20 to the second child device 20b is calculated based on the information described in the LQL. Assuming that all hops "use the first MAC 103 and the first PHY 102 with a low transmission rate", the 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 child device 20b selects, in the second upstream route construction unit 321, the node that has the smallest RPL rank 2 of the route from the second collection device 20 to the second child device 20b as the next upstream hop (parent node) to the second collection device 20.

[0091] FIG. 20 shows a route table 902 held by the second child device 20b when the second collection device 20 is selected as the parent node. The second child device 20b manages RPL rank 1, RPL rank 2, the ID of the parent node selected by RPL rank 2, the type of parent node, the wireless method 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 child device on the path, and the presence or absence of a first child device on the path.

[0092] The route table 902 of the second slave unit 20b is as follows: *RPL Rank 1=256 *RPL Rank 2=64 *Parent node ID=20 *Parent node type = Secondary collector *Wireless method with parent node = Second PHY / MAC *High transmission rate continuous = 1 * Third handset available = No *First handset available = No

[0093] Furthermore, the second child device 20b creates a DAO (DODAG Advertisement Object) message (DAO-2) in the second multi-hop communication unit 302, which includes the parent node ID, the node type of the own node, and the wireless system with the parent node. 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 child device 20b should be processed by the second multi-hop communication unit 302 and the second downlink route construction unit 320. The second downstream path construction unit 320 records in the downstream path table 901 the parent node ID selected by the second slave device 20b written in DAO-2 and the wireless system for the parent node.

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

[0096] FIG. 22 shows a wireless system bitmap and a source routing header that are added to a downstream message addressed to the second slave unit 20b in the second collection device 20. In FIG. The wireless system bitmap specifies the wireless system from the first bit to the first hop, second hop, etc., using a reserved area that is ignored by the first child device. If the wireless system is the first PHY / MAC, the bit value is 0, and if it is the second PHY / MAC, the bit value is 1. The source routing header lists the node IDs of the nodes through which the message will travel on its way to its destination in the order of hops.

[0097] When the second slave unit 20b receives the downstream message in which the wireless communication system bitmap and the source routing header are described, the second slave unit 20b refers to the wireless communication system bitmap and the source routing header and determines that the message is addressed to the own node.

[0098] When the first handset 10f joins via the second handset 20b The operation of the first handset 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 through the first MAC 103 and the first PHY .

[0099] The second slave device 20b, which has received the 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 the DIS-1 by broadcasting the DIO-2 in the first MAC 103 and the first PHY 102. *RPL rank of own node is 2 *MinimumHopRankIncrease-2 used in the second multi-hop communication *Wireless system that the node can support (first PHY 102 and first MAC 103, second PHY 202 and second MAC 203) *Device type of the own node * Consecutive high transmission rates from the second collection device

[0100] The second child device 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 *Radio method = 2nd PHY / MAC *Device type = Second handset *High transmission rate continuous = 1

[0101] Furthermore, the second slave device 20b 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 the DIS-1 by broadcasting the DIO-1 in the first MAC 103 and the first PHY 102. *RPL rank of own node is 1 *MinimumHopRankIncrease-1 used in the first multi-hop communication

[0102] The second child 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 the DIO-2 as an undefined message and decides to process the 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 written in the DIO-1, the MinimumHopRankIncrease-1 written 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 acquired when receiving the DIO-1.

[0105] If the metric representing the state between the wireless links is 0, the first slave unit 10f receives the metric described in the DIO-1 of the second slave unit 20b. RPL rank 1 = 256, MinimumHopRankIncrease-1=128 and The RPL rank of the local node is calculated as 1=384.

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

[0107] FIG. 23 shows the RPL rank 1 held in the route table 902 of the first child device 10f when the second child device 20b is selected as a parent node and the ID of the selected parent node. Furthermore, the first slave device 10a creates, in the first multi-hop communication unit 301, a DAO (DODAG Advertisement Object) message (DAO-1) including a parent node ID. The first slave device 10f transmits 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 by the protocol determination unit 330 that the DAO-1 received from the first slave device 10f should be processed by the first multi-hop communication unit 301 and the second downlink route construction unit 320. Since the type of wireless link (wireless system) is not described in DAO-1, ​​the second downlink path establishment unit 320 determines the wireless system to be the first PHY / MAC. The second downlink route construction unit 320 records in the downlink route table 901 the parent node ID selected by the first child device 10f described in DIO-1 and the type of wireless link (wireless method) used by the parent node to hop to the first child device 10f.

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

[0110] FIG. 25 shows a wireless system bitmap and a source routing header that are added to a downstream message addressed to the first slave unit 10f in the second collection device 20. In FIG. The wireless system bitmap specifies the wireless system from the first bit to the first hop, second hop, etc., using a reserved area that is ignored by the first child device. If the wireless system is the first PHY / MAC, the bit value is 0, and if it is the second PHY / MAC, the bit value is 1. The source routing header lists the node IDs of the nodes through which the message will travel on its way to its destination in the order of hops.

[0111] When the second slave device 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 transfers the message to the first slave device 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 slave device 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 through the first MAC 103 and the first PHY .

[0113] The second slave device 20b, which has received the 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 the DIS-1 by broadcasting the DIO-2 in the first MAC 103 and the first PHY 102. *RPL rank of own node is 2 *MinimumHopRankIncrease-2 used in the second multi-hop communication *Wireless system that the node can support (first PHY 102 and first MAC 103, second PHY 202 and second MAC 203) *Device type of the own node * Consecutive high transmission rates from the second collection device

[0114] The second child device 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 *Radio method = 2nd PHY / MAC *Device type = Second handset *High transmission rate continuous = 1

[0115] Furthermore, the second slave device 20b 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 broadcasts DIO-1 in the first MAC 103 and the first PHY 102 to respond to DIS-1. *RPL rank 1 of own node *MinimumHopRankIncrease-1 used in the first multi-hop communication

[0116] The second child 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 child device 20g, which receives DIO-2 and DIO-1 from the second child device 20b, determines by 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.

[0118] The second upstream path construction unit 321 of the second terminal 20g The RPL rank of the second slave unit 20b described in the DIO-2 is 2; MinimumHopRankIncrease-2 described in the DIO-2; a metric indicating a state 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 acquired when receiving the DIO-2; Calculate the RPL rank 2 of the own node from this.

[0119] The second slave device 20g calculates the RPL rank 2=96 from the information recorded in DIO-2 of the second slave device 20b and the metric of the wireless link as follows. RPL rank 2=(RPL rank 2 of the second child device 20b (=64)+MinimumHopRankIncrease-2 (=32)+Metric (=0))=96

[0120] The first upstream path establishment unit 311 of the second terminal 20g The RPL rank of the second slave unit 20b described in the DIO-1 is 1; MinimumHopRankIncrease-1 described in the DIO-1; a metric indicating a state between 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 acquired when receiving the DIO-1; From this, the RPL rank 1 of the own node is calculated.

[0121] If the metric representing the state between the wireless links is 0, the second slave device 20g receives the metric described in the DIO-1 of the second slave device 20b. RPL rank 1 = 256, MinimumHopRankIncrease-1=128 and The RPL rank of the local node is calculated as 1=384.

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

[0123] FIG. 26 shows the route table 902 held by the second child device 20g when the second child device 20b is selected as the parent node. The second child device 20g manages RPL rank 1, RPL rank 2, the ID of the parent node selected by RPL rank 2, the type of parent node, the wireless method 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 child device on the path, and the presence or absence of a first child device on the path.

[0124] The route table 902 of the second child device 20g is as follows: *RPL Rank 1=384 *RPL Rank 2=96 *Parent node ID=20b *Parent node type = 2nd child *Wireless method with parent node = Second PHY / MAC *High transmission rate continuous = 2 * Third handset available = No *First handset available=No

[0125] Furthermore, the second child device 20g creates, in the second multi-hop communication unit 302, 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. 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 route construction unit 320. The second downstream path construction unit 320 records in the downstream path table 901 the parent node ID selected by the second slave device 20g written in DAO-2 and the wireless system for the parent node.

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

[0128] FIG. 28 shows a wireless system bitmap and a source routing header that are added to a downstream message addressed to the second slave unit 20g in the second collection device 20. In FIG. The wireless system bitmap specifies the wireless system from the first bit to the first hop, second hop, etc., using a reserved area that is ignored by the first child device. If the wireless system is the first PHY / MAC, the bit value is 0, and if it is the second PHY / MAC, the bit value is 1. The source routing header lists the node IDs of the nodes through which the message will travel on its way to its destination in the order of hops.

[0129] When the second slave device 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 transfers the message to the second slave device 20g using the second PHY / MAC.

[0130] ● The third handset 30h joins via the second handset 20b An operation for the third handset 30h to join the communication system 502 will be described. The third slave device 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 through the first MAC 103 and the first PHY .

[0131] The second slave device 20b that has received the DIS-1 from the third slave device 30h 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 the DIS-1 by broadcasting the DIO-2 in the first MAC 103 and the first PHY 102. *RPL rank of own node is 2 *MinimumHopRankIncrease-2 used in the second multi-hop communication *Wireless system that the node can support (first PHY 102 and first MAC 103, second PHY 202 and second MAC 203) *Device type of the own node * Consecutive high transmission rates from the second collection device

[0132] The second child device 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 *Radio method = 2nd PHY / MAC *Device type = Second handset *High transmission rate continuous = 1

[0133] Furthermore, the second slave device 20b describes 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 the DIS-1 by broadcasting the DIO-1 in the first MAC 103 and the first PHY 102 of the second communication device 200. *RPL rank of own node is 1 *MinimumHopRankIncrease-1 used in the first multi-hop communication

[0134] The second child 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 child device 30h, which receives DIO-2 and DIO-1 from the second child 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.

[0136] The second upstream path construction unit 321 of the third slave unit 30h The RPL rank of the second slave unit 20b described in the DIO-2 is 2; MinimumHopRankIncrease-2 described in the DIO-2; A metric indicating a state between 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 acquired when receiving the DIO-2; The weight of using 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, and Calculate the RPL rank 2 of the own node from this.

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

[0138] The first upstream path establishment unit 311 of the third slave unit 30h The RPL rank of the second slave unit 20b described in the DIO-1 is 1; MinimumHopRankIncrease-1 described in the DIO-1; A metric indicating 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 acquired when receiving the DIO-1. From this, the RPL rank 1 of the own node is calculated.

[0139] If the metric representing the state between the wireless links is 0, the third slave unit 30h is in the state of the wireless link metric described in the DIO-1 of the second slave unit 20b. RPL rank 1 = 256, MinimumHopRankIncrease-1=128 and The RPL rank of the local node is calculated as 1=384.

[0140] The third slave unit 30h may not be able to receive DIO-1 due to a communication failure. If the third slave unit 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 the RPL rank 1.

[0141] The operation of the protocol conversion unit 370 is as follows. In the communication system 502, it is assumed that LQL (Link Quality Level) is adopted as a metric representing the state between wireless links. The number of hops from the second collection device 20 to the third child device 30h is calculated based on the information described in the LQL. Assuming that all hops "use the first MAC 103 and the first PHY 102 with a low transmission rate", the 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 child device 30h selects, in the second upstream route construction unit 321, the node that has the smallest RPL rank 2 of the route from the second collection device 20 to the third child device 30h as the next upstream hop (parent node) to the second collection device 20.

[0143] FIG. 29 shows a route table 902 held by the third child device 30h when the second child device 20b is selected as the parent node. The third child device 30h manages RPL rank 1, RPL rank 2, the ID of the parent node selected by RPL rank 2, the type of parent node, the wireless method 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 child device on the path, and the presence or absence of a first child device on the path.

[0144] The route table 902 of the third slave unit 30h is as follows: *RPL Rank 1=384 *RPL Rank 2=128 *Parent node ID=20b *Parent node type = 2nd child *Wireless method with parent node = 1st PHY / MAC *High transmission rate continuous = 1 * Third handset available = Yes *First handset available = No

[0145] Furthermore, the third slave device 30h creates, in the second multi-hop communication unit 302, 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. The third slave device 30h transmits the DAO-2 to the second collecting 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 route construction unit 320. The second downstream path construction unit 320 records in the downstream path table 901 the parent node ID selected by the third slave device 30h written in DAO-2 and the wireless system with the parent node.

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

[0148] FIG. 31 shows a wireless system bitmap and a source routing header that are added to a downstream message addressed to the second slave unit 20g in the second collection device 20. In FIG. The wireless system bitmap specifies the wireless system from the first bit to the first hop, second hop, etc., using a reserved area that is ignored by the first child device. If the wireless system is the first PHY / MAC, the bit value is 0, and if it is the second PHY / MAC, the bit value is 1. The source routing header lists the node IDs of the nodes through which the message will travel on its way to its destination in the order of hops.

[0149] When the second slave device 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 transfers the message to the third slave device 30h using the first PHY / MAC.

[0150] FIG. 32 shows a sequence when the third handset 30c and the second handset 20i join the communication system 502 in FIG. When the third slave unit 30c joins the second collection device An operation for the third handset 30c to join the communication system 502 will be described. The third slave terminal 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 through the first MAC 103 and the first PHY .

[0151] The second collection device 20 that has received DIS-1 from the third child device 30c 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 of own node is 2 *MinimumHopRankIncrease-2 used in the second multi-hop communication *Wireless system that the node can support (first PHY 102 and first MAC 103, second PHY 202 and second MAC 203) *Device type of the own node * 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 path information in DIO-2 and broadcasts it. *RPL Rank 2=32 *MinimumHopRankIncrease-2=32 *Radio method = 2nd PHY / MAC *Device type = Secondary 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 broadcasts DIO-1 in the first MAC 103 and the first PHY 102 to respond to DIS-1. *RPL rank of own node is 1 *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. *RPL Rank 1=128 *MinimumHopRankIncrease-1=128

[0155] The third child device 30c, which receives DIO-2 and DIO-1 from the second collection device 20, determines by 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 unit 30c is The RPL rank 2 of the second collection device 20 described in the DIO-2; MinimumHopRankIncrease-2 described in the DIO-2; A metric indicating a state between the wireless link between the second communication device 200 of the second collection device 20 and the first communication device 100 of the third child device 30c, which is acquired when receiving the DIO-2; The weight of using 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, and Calculate the RPL rank 2 of the own node from

[0157] The third slave 30c calculates RPL rank 2=96 from the information recorded in DIO-2 of the second collection device 20 and the metrics of the wireless link as follows. RPL rank 2 = (RPL rank 2 of the second collection device 20 (= 32) + Minimum HopRank Increase - 2 (= 32) x low transmission rate weight (= 2) + metric (= 0)) = 96

[0158] The first upstream path construction unit 311 of the third slave unit 30c The RPL rank of the second collection device 20 described in the DIO-1 is 1; MinimumHopRankIncrease-1 described in the DIO-1; a metric indicating a state between the wireless link between the second communication device 200 of the second collection device 20 and the first communication device 100 of the third child device 30c, the metric being acquired when receiving the DIO-1; Calculate the RPL rank 1 of the own node from

[0159] If the metric representing the state between the wireless links is 0, the third child device 30c is connected to the DIO-1 of the second collection device 20. RPL rank 1 = 128, MinimumHopRankIncrease-1=128 and Calculate the RPL rank 1 of the own node = 256 from this.

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

[0161] FIG. 33 shows the route table 902 held by the third child device 30c when the second collection device 20 is selected as the parent node. The third child device 30c manages RPL rank 1, RPL rank 2, the ID of the parent node selected by RPL rank 2, the type of parent node, the wireless method 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 child device on the path, and the presence or absence of a first child device on the path.

[0162] The route table 902 of the third slave unit 30c is as follows: *RPL Rank 1=256 *RPL Rank 2=96 *Parent node ID=20 *Parent node type = Secondary collector *Wireless method with parent node = 1st PHY / MAC *Continuous high transmission rate = 0 * Third handset available = Yes *First handset available=No

[0163] Furthermore, the third slave terminal 30c creates, in the second multi-hop communication unit 302, 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. The third child device 30c transmits the DAO-2 to the second collection 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 route construction unit 320. The second downstream path construction unit 320 of the second collection device 20 records in the downstream path table 901 the parent node ID selected by the third child device 30c described in DAO-2 and the wireless system with the parent node.

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

[0166] FIG. 35 shows a wireless system bitmap and a source routing header that are added to a downstream message addressed to the third slave unit 30c in the second collection device 20. In FIG. The wireless system bitmap specifies the wireless system from the first bit to the first hop, second hop, etc., using a reserved area that is ignored by the first child device. If the wireless system is the first PHY / MAC, the bit value is 0, and if it is the second PHY / MAC, the bit value is 1. The source routing header lists the node IDs of the nodes through which the message will travel on its way to its destination in the order of hops.

[0167] When the third slave unit 30c receives the downstream message in which the wireless communication system bitmap and the source routing header are described, the third slave unit 30c refers to the wireless communication system bitmap and the source routing header and determines that the message is addressed to the 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 slave device 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 through the first MAC 103 and the first PHY .

[0169] The third slave 30c, which has received the DIS-1 from the second slave 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 the DIS-1 by broadcasting the DIO-2 in the first MAC 103 and the first PHY 102. *RPL rank of own node is 2 *MinimumHopRankIncrease-2 used in the second multi-hop communication *Wireless system that the node can support (first PHY 102 and first MAC 103, second PHY 202 and second MAC 203) *Device type of the own node * Consecutive high transmission rates from the second collection device

[0170] The third child device 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 *Radio method = 1st PHY / MAC *Device type = 3rd handset *Continuous high transmission rate = 0 * Third handset available = Yes *First handset available=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 the DIS-1 by broadcasting the DIO-1 in the first MAC 103 and the first PHY 102. *RPL rank of own node is 1 *MinimumHopRankIncrease-1 used in the first multi-hop communication

[0172] The third child 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 child device 20i, which receives DIO-2 and DIO-1 from the third child device 30c, determines by 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.

[0174] The second upstream path construction unit 321 of the second slave unit 20i The RPL rank of the third slave unit 30c described in the DIO-2 is 2; MinimumHopRankIncrease-2 described in the DIO-2; A metric indicating a state between 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 acquired when receiving the DIO-2; The weight of using 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, and Calculate the RPL rank 2 of the own node from

[0175] The second slave device 20i calculates the RPL rank 2=160 from the information recorded in the DIO-2 of the third slave device 30c and the metric of the wireless link as follows. RPL rank 2 = (RPL rank 2 of the third child device 30c (= 96) + Minimum HopRank Increase - 2 (= 32) x low transmission rate weight (= 2) + metric (= 0)) = 160

[0176] The first upstream path construction unit 311 of the second slave unit 20i The RPL rank of the third slave unit 30c described in the DIO-1 is 1; MinimumHopRankIncrease-1 described in the DIO-1; A metric indicating 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 acquired when receiving the DIO-1. From this, the RPL rank 1 of the own node is calculated.

[0177] If the metric representing the state between the wireless links is 0, the second slave unit 20i is in the state of the DIO-1 of the third slave unit 30c. RPL rank 1 = 256, MinimumHopRankIncrease-1=128 and The RPL rank of the local node is calculated as 1=384.

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

[0179] FIG. 36 shows the route table 902 held by the second child device 20i when the third child device 30c is selected as the parent node. The second child device 20i manages RPL rank 1, RPL rank 2, the ID of the parent node selected by RPL rank 2, the type of parent node, the wireless method 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 child device on the path, and the presence or absence of a first child device on the path.

[0180] The route table 902 of the second child device 20i is as follows. *RPL Rank 1=384 *RPL Rank 2=160 *Parent node ID=30c *Parent node type = 3rd child *Wireless method with parent node = 1st PHY / MAC *Continuous high transmission rate = 0 * Third handset available = Yes *First handset available=No

[0181] Furthermore, the second child device 20i creates, in the second multi-hop communication unit 302, 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. 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 the DAO-2 received from the second slave device 20i should be processed by the second multi-hop communication unit 302 and the second downlink route construction unit 320. The second downstream path construction unit 320 records in the downstream path table 901 the parent node ID selected by the second slave device 20g written in DAO-2 and the wireless system for the parent node.

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

[0184] FIG. 38 shows a wireless system bitmap and a source routing header that are added to a downstream message addressed to the second child unit 20i in the second collection device 20. In FIG. The wireless system bitmap specifies the wireless system from the first bit to the first hop, second hop, etc., using a reserved area that is ignored by the first child device. If the wireless system is the first PHY / MAC, the bit value is 0, and if it is the second PHY / MAC, the bit value is 1. The source routing header lists the node IDs of the nodes through which the message will travel on its way to its destination in the order of hops.

[0185] When the third slave device 30c 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 20i using the first PHY / MAC.

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

[0187] In FIG. 4, even if the second child device 20d is capable of communicating with the third child device 30c in addition to the first child device 10a, the second child device 20d selects the third child device 30c, which does not have the first child device 10a on the path from the parent device, as the parent node. RPL rank 2 calculated from the first slave unit 10a=160 RPL rank 2 calculated from the third child device 30c=160 In this way, the second slave terminal 20x operating under the second protocol is a wireless device that is more likely to select the third slave terminal 30x as a parent node than the first slave terminal 10x (third slave terminal 30x>first slave terminal 10x).

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

[0189] Probability of being selected as a parent node (Second handset 20x>third handset 30x>first handset 10x) In FIG. 4, if the second child device 20d is capable of communicating with the second child device 20b in addition to the first child device 10a, the second child device 20d selects the second child device 20b as a parent node. RPL rank 2 calculated from the first slave unit 10a=160 RPL rank 2 calculated from the second child device 20b=96 Similarly, in FIG. 4, if the third child device 30e is able to communicate with the second child device 20b and the third child device 30c in addition to the first child device 10a, the third child device 30e selects the second child device 20b as its parent node. RPL rank 2 calculated from the first slave unit 10a=160 RPL rank 2 calculated from the second child device 20b=128 RPL rank 2 calculated from the third child device 30c=160 In this manner, the second slave device 20x operating under the second protocol is a wireless device that is more likely to be selected as a parent node than the first slave device 10a and the third slave device 30x (second slave device 20x>third slave device 30x, second slave device 20x>first slave device 10x).

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

[0191] Summary of the first embodiment As described above, in the first embodiment, the communication system 502 including the second collection device 20, the first slave device 10x, the second slave device 20x, and the third slave device 30x has been described. The second collection device 20, the second child device 20x, and the third child device 30x each transmit DIO-1 including RPL rank 1 used in the first multi-hop communication of the first child device 10x, and DIO-2 including RPL rank 2 used in the second multi-hop communication of the second child device and the third child device. This enables migration of the multi-hop network by establishing a second multi-hop communication while maintaining the first multi-hop communication. In addition, the calculation method of 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 slave device to select a wireless communication system with the second PHY / MAC (high transmission rate) for use on the path to the second collection device, thereby enabling an improvement in system throughput.

[0192] Explanation of the variation of the first embodiment ● Request DIO-2 only In this embodiment, the second and third slave devices participating in the wireless mesh network transmit DIS-1 and wait for responses from DIO-2 and DIO-1. The second and third slaves may transmit DIS-2 notifying that their own nodes support the second multi-hop communication, and may request only DIO-2 from the second collection device, the second slave, and the third slave that support the second multi-hop communication. Furthermore, if no response to DIS-2 is received within a certain period of time, the second or third slave may transmit DIO-1 to wait for DIO-1 from the first slave. When the second and third child 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 of 1.

[0193] Disposal of DIO-1 In this embodiment, the second and third child devices process DIO-1 transmitted from the other second and third child devices in the first multi-hop communication unit. By including an identifier in the DIO-1 of the second and third child devices that transmits the DIO-1 indicating that the transmission is from the second or third child device, the second and third child devices that receive the DIO-1 may discard the DIO-1 without processing it. Alternatively, if the second and third child devices have received DIO-2 from another second or third child device, the sending node may be recorded and DIO-1 sent from a node that has already received DIO-2 may not be processed. Even if the second and third child 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 the present embodiment, it has been 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 slave device and the third slave device may add route information that does not exist in DIO-1 and is described only in DIO-2 as an RPL option of DIO-1 and transmit the same to construct a wireless mesh network of the second multi-hop communication and the first multi-hop communication. Alternatively, the second slave device and the third slave device may construct a wireless mesh network of the second multi-hop communication and the first multi-hop communication by describing route information that does not exist in DIO-1 and is described only in DIO-2 in a reserved area of ​​DIO-1 that is ignored by the first slave device and transmitting the same.

[0195] ●Downstream message format In this embodiment, the wireless method (second PHY / MAC or first PHY / MAC) used by the second collection device when sending 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 collection device 10 In this embodiment, the second collection device 20 is used for the DAGRoot of the RPL, but the first collection device 10 may be used for the DAGRoot of the RPL. Even when the first collection device 10 is used, the second and third child devices can calculate the RPL rank 2 from the contents described in DIO-1 by the operation of the protocol conversion unit 370. Therefore, DIO-2 and DIO-1 can be transmitted downstream from the second and third child devices (when traffic destined for the collection device is considered as upstream). At that time, the first collection device 10 ignores the wireless system and node type information with the parent node notified by the second and third child devices via DAO-2, 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 with the second slave or the third slave.

[0197] Type of weighting In this embodiment, the transmission rate of the wireless link of the second handset is compared with the transmission rate of the wireless link of the first handset and the third handset, and the transmission rate of the wireless link of the first handset and the third handset is set to the low transmission rate. When calculating RPL rank 2, RPL rank 2 is calculated by multiplying MinimumHopRankIncrease-2 by a coefficient (weighted for low transmission rate). However, RPL rank 2 may be calculated by adding a cost for using a low transmission rate.

[0198] ● Weighting of RPL rank value In this embodiment, the RPL rank value is weighted (weighted four times) according to the difference in transmission rate of the wireless link, but weighting may also be performed according to the packet loss rate, delay, throughput, and their average and variance.

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

[0200] ●Type of line Although the present embodiment has been described with respect to wireless communication, wired communication may also be included in part.

[0201] Embodiment 2 In the first embodiment, the 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 the RPL rank 2, which is an index for route selection in the second multi-hop communication, in the second child device 20x and the third child device 30x will be described.

[0202] FIG. 39 is a flowchart showing parent node selection in the second and third child devices. FIG. 40 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 second slave 20c.

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

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

[0205] Under this condition, step S001 in the flowchart for parent node selection in the second and third child machines in Figure 39 is Yes, and step S002 causes the second child machine 20d to select the second child machine 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 20d receives DIO-1 from the first slave 10a and DIO-2 and DIO-1 from the third slave 30c by the process described in embodiment 1. The second slave 20d calculates RPL rank 2 when the first slave 10a is selected as the parent node and RPL rank 2 when the third slave 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 child device 10a is selected as the parent node is 160 (rank of the second collector (=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)×low transmission rate weight (=2)+metric (=0)).

[0209] Under this condition, step S001 in the flowchart of parent node selection in the second and third slave units in Figure 39 is 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 device 20d joins a wireless mesh network configured with a second collection device 20, a first slave device 10a, and second slave devices 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 by the process described in embodiment 1. The second slave 20d calculates RPL rank 2 when the first slave 10a is selected as the parent node and 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. The RPL rank 2 when the first child device 10a is selected as the parent node is 160 (rank of the second collector (=32)+MinimumHopRankIncrease-2 (=32)×number of hops (=2)×low transmission rate weight (=2)+metric (=0)).

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

[0212] Under this condition, step S001 in the flowchart for parent node selection in the second and third child devices in Figure 39 becomes No, step S003 becomes Yes, and step S004 causes the second child device 20d to select the second child device 20e, which has the largest value of the succession of high transmission rates, as its parent node.

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

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

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

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

[0217] Under this condition, step S001 in the flowchart of parent node selection in the second and third child devices in Figure 39 will be No, step S003 will be No, and step S005 will be Yes, and in step S006, the second child device 20d will select the third child device 30c, on whose path there is no first child device, as the parent node.

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

[0219] The second child device 20d receives DIO-1 from the first child devices 10e and 10c by the processing described in embodiment 1, and calculates the RPL rank 2 when the first child device 10e is selected as the parent node and the RPL rank 2 when the first child device 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 child device 10e is selected as the parent node is 224 (RPL rank 2 (=32) of the second collection device 20+MinimumHopRankIncrease-2 (=32)×low transmission rate weight (=2)×number of hops (=3)+metric (=0)).

[0221] Similarly, when the first child device 10c is selected as the parent node, the RPL rank 2 becomes 224 (RPL rank 2 of the second collection device 20 (= 32) + MinimumHopRankIncrease-2 (= 32) × low transmission rate weighting (= 2) × 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 child units in FIG. 39 will be No, step S003 will be No, and step S005 will be No, and step S007 will cause the second child unit 20d to randomly select either the first child unit 10e or the first child 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. In this way, a route in which the vicinity of the second collection device 20 is configured with a high transmission rate wireless link 602 is preferentially selected, and system throughput can be improved by avoiding passing through the first child device, which is a traffic bottleneck.

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

[0225] Embodiment 3 In the first embodiment, a sequence has been described in which the second child device 20x and the third child device 30x perform node replacement from the first child device 10x to the second child device 20x and the third child device 30x by transmitting DIO-2 and DIO-1. 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 node replacement is completed and the first child 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] Fig. 48 shows a sequence of transmitting DIO-2 and DIO-1 in the second collecting device 20, the second child devices 20b, 20f, 20g, and the third child device 30h in Fig. 47. The second collecting device 20, the second child devices 20b, 20f, 20g, and the third child 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 child 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 after the next expiration of the Trickle timer, and stops transmitting from DIO-1.

[0228] When the second slave units 20b, 20f, 20g and the third slave unit 30h receive DIO-2 with a flag set to indicate that the first slave unit 10x does not exist, they set a flag in DIO-2 to indicate that the first slave unit 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 collecting device 20 is notified that the first child unit is not present, and a flag is retained in DIO-2 to notify the second collecting device, the second child unit, and the third child unit that the first child unit is not present, thereby stopping transmission from DIO-1 and improving wireless usage efficiency.

[0230] In the third embodiment, the administrator 1000 directly instructs the second collection device 20 that the first child device does not exist. As another instruction method, the second collection 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 collection device may check the type of node participating in the communication system 503 and autonomously determine to stop transmission of DIO-1 by determining that the first child device is not present. Alternatively, the second and third child devices may determine that they have not received DIO-1 from the first child device for a certain period of time and autonomously decide to stop transmitting 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 an existing wireless device (first collection device 10, first slave device 10x) to a new wireless device (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) and selects a master unit. The communication system 502 calculates RPL rank 1 (first rank value) and RPL rank 2 (second rank value) to select a master unit. The new wireless device (second collection device 20: parent device) that will become DAGROOT supports an existing communication method (first PHY / MAC) and an existing first protocol, as well as a new communication method (second PHY / MAC) and a new second protocol. Some new wireless devices (second slave devices 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 slave devices 30x) are compatible with the existing communication method (first PHY / MAC) and the existing first protocol and the 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 child device 20x), and the new wireless device (third child device 30x) transmit a control message (DIO-2) for the new wireless device (second child device 20x, third child device 30x) and a control message (DIO-1) for the existing wireless device (first child device 10x). The control message (DIO-2) for the new wireless devices (second wireless device 20x, third wireless device 30x) is in a format that is discarded by the existing wireless device (first wireless device 10x). The control message (DIO-2) for the new wireless devices (second handset 20x, third handset 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) Number of consecutive new communication methods (second PHY / MAC) (2B) Presence or absence of existing wireless device (first handset 10x) (2C) Presence or absence of new wireless device (third handset 30x) By specifying a flag in a control message (DIO-2) for new wireless devices (second handset 20x, third handset 30x), the control message (DIO-1) for the existing wireless device (first handset 10x) can be stopped.

[0233] ● New radio (second handset 20x, third handset 30x) The new wireless device (second wireless device 20x, third wireless device 30x) calculates and stores RPL rank values ​​(RPL rank 2 and RPL rank 1) in a control message (DIO-2) for the new wireless device (second wireless device 20x, third wireless device 30x) and a control message (DIO-1) for the existing wireless device (first wireless device 10x). The new wireless device (second wireless device 20x, third wireless device 30x) selects a parent node using the RPL rank value (RPL rank 2) calculated in the control message (DIO-2) for the new wireless device (second wireless device 20x, third wireless device 30x).

[0234] When a new wireless device (second wireless device 20x, third wireless device 30x) can only receive a control message (DIO-1) for an existing wireless device (first wireless device 10x), the protocol conversion unit 370 assumes that all hops from the parent device have passed through the existing wireless device (first wireless device 10x) and calculates an RPL rank value (RPL rank 2). When a new wireless device (second wireless device 20x, third wireless device 30x) can only receive a control message (DIO-2) for the new wireless device (second wireless device 20x, third wireless device 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 wireless device 10x). When the new wireless device (second wireless device 20x, third wireless device 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 wireless device (first wireless device 10x).

[0235] Setting and calculating rank values The communication system 502 sets the RPL rank value in advance as follows, so that when calculating the RPL rank value, it is possible to calculate RPL rank 2 (second rank value) from RPL rank 1 (first rank value). (1) An initial rank value prestored in the second collection device 20 RPL Rank 1>RPL Rank 2 RPL Rank 1 = RPL Rank 2 x 4 (2) A minimum increment value per hop that is prestored in the second collection device 20 MinimumHopRankIncrease-1>MinimumHopRankIncrease-2 MinimumHopRankIncrease-1=MinimumHopRankIncrease-2x4 (3) A minimum increment value per hop that is prestored in the second handset 20x and the third handset 30x MinimumHopRankIncrease-1>MinimumHopRankIncrease-2 MinimumHopRankIncrease-1=MinimumHopRankIncrease-2x4

[0236] Priority of parent unit selection The case where the RPL rank value (RPL rank 2) is calculated and a parent node is selected based on a control message (DIO-2) for new wireless devices (second handset 20x, third handset 30x) is as follows.

[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 between 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) A large number of consecutive new communication methods (second PHY / MAC) (2B) An existing wireless device (first slave device 10x) does not exist on the path from the master device to the own node, or a new wireless device (third slave device 30x) does not exist on the path from the master device to the own node.

[0239] ● Announcement message (DAO-1 and DAO-2) The existing wireless device (first slave device 10x) notifies the master device of the ID of the parent node in a notification message (DAO-1) that is sent to the master device. The new wireless devices (the second slave device 20x and the third slave device 30x) record in the route table 902 the ID of the parent node and the wireless method (PHY / MAC) used for communication with the parent node. The new wireless devices (second child device 20x, third child device 30x) notify the parent node of the parent node ID, the device type of the node itself, and the wireless method (PHY / MAC) to be used for communication with the parent node in the announcement message (DAO-2) that they send to the parent node. The parent device holds in a downlink route table 901 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.

[0240] Downstream traffic operation of parent unit (1) The new wireless device (parent device) stores in a downlink route table 901 the wireless system (PHY / MAC) supported by each wireless device (child device). (2) When a new wireless device (parent device) sends downstream traffic, it specifies the wireless devices (child devices) to pass through and the wireless method (PHY / MAC) to use for the hop. The new wireless device (master) uses a bitmap as a method for specifying the wireless system, or uses a TLV as a method for specifying the wireless system. (3) If there is a wireless device (slave) 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 wireless device (first child device 10x) (1) When an existing wireless device (first child device 10x) forwards a downstream message in downstream traffic, it uses the ID of the destination wireless device described in the downstream message and uses the existing wireless method (first PHY / MAC).

[0242] Downstream traffic operation of the new wireless device (second handset 20x) (1) When a new wireless device (second child device 20x) forwards a downstream message in downstream traffic, it uses the ID of the destination wireless device and the wireless method (PHY / MAC) used for the forwarding, which are written in the downstream message. (2) If the wireless system (PHY / MAC) is not specified, the existing wireless system (first PHY / MAC) is used.

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

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

[0245] The communication device (second communication device 200) receives, as a control message, from one node, A first control message (DIO-1) including route information of the first rank information of the source node; A second control message (DIO-2) containing the second rank information of the source node in the route information. Receive. The slave device includes a first upstream path establishment unit 311 and a second upstream path establishment 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 one of first rank information and 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 (RPLRank1) and a first minimum increase value (MinimumHopRankIncrease-1). The second rank information includes a second rank value (RPLRank2) and a second minimum increase value (MinimumHopRankIncrease-2).

[0247] When a communication device (second communication device 200) receives only a first control message including first rank information in route information from one child device as a control message, (1) The first upstream route construction unit 311 calculates a first rank value (RPL rank 1) based on the first rank information. (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 parent device to the child device.

[0248] When the communication device (second communication device 200) receives only a second control message including second rank information in the route information from one child device as a control message, (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. (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 upstream route construction unit 321 calculates the second rank value by weighting so that there is a difference between the second rank value when the second communication method is used and the second rank value when the first communication method is used.

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

[0251] The route information includes the presence or absence of nodes on the route from the parent device that are not capable 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 path construction unit 360 selects the parent node based on whether or not there is a node (first child device 10x or third child device 30x) that is not capable of the second communication method (second PHY / MAC).

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

[0254] When a parent node and a 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 downstream message including the IDs of nodes present on the path to the slave device that sends the downstream message and the communication method with the nodes. The first multi-hop communication unit 301 of the first child device 10x identifies the ID of the child node by referring only to the node ID included in the downstream message, and transfers the downstream message to the child node. The multi-hop communication unit 340 of the second child device 20x and the third child device 30x identifies the child node ID and the communication method with the child node by referring to the node ID and the communication method with the node included in the downstream message, and forwards the downstream message to the child node.

[0256] A master device (second collection device 20) is connected to a wireless mesh network in which the master device and a plurality of slave devices communicate with each other as nodes. The master (second collection device 20) includes a communication device (second communication device 200), a downstream route construction unit 350, and a multi-hop communication unit 340. The communication device (second communication device 200) receives a notification message (DAO-2) from the child nodes (second child device 20x, third child device 30x) notifying the parent node ID and the communication method with the parent node. The downstream route construction unit 350 records the parent node ID and the communication method with the parent node contained in the announcement message (DAO-2) in the downstream route table 902 in association with the child node ID. The multi-hop communication unit 340 refers to the downstream route table 902, identifies one or more nodes existing on the route to the child device that sends the downstream message, and creates a downstream message including the node ID and the communication method with the node.

[0257] The downstream route construction unit 350 records in the rank table 903 the first rank information (the first rank value and MinimumHopRankIncrease−1) and the second rank information (the second rank value and MinimumHopRankIncrease−2). The multi-hop 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 capable of communicating using a first protocol and a 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 (the second collection device 20) and the child devices (the second child device 20x and the third child device 30x) communicate with each other using only the second protocol. The parent device (second collection device 20) transmits a downstream message including the node ID and the communication method with the node. The child devices (second child device 20x, third child device 30x) receive the downstream message, refer to the node ID and the communication method with the node contained in the downstream message to identify the child node ID and the communication method with the child node, and forward the downstream message to the child node.

[0260] Embodiment 4 In the first embodiment, a wireless mesh network is constructed with the second collecting device 20, the first child device 10x, the second child device 20x, and the third child device 30x, and a method is described in which the second collecting device 20 specifies the wireless method by referring to the downstream route table 901 when sending a downstream message from the second collecting device 20.

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

[0262] 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. In FIG. 49, it is assumed that the first terminal 10x, the second terminal 20x, and the third terminal 30x can 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 must be referenced or processed by all nodes on the route of an IPv6 packet.

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

[0264] ● Operation of the child device (assignment of child device ID and wireless method) The second handset 20b communicates with the multi-hop communication unit 340. 、H The op-by-hop extension header contains identifier: 1 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 ID: 20b of the second child device 20b, and the upstream message is sent to the parent node, the second collection device 20.

[0265] The second slave terminal 20b may transmit the upstream message of this embodiment to the parent node at any time after the second slave terminal 20b completes the joining operation to the communication system 504. Specifically, the following cases are possible: (1) When the slave unit completes the operation of joining the communication system 504 (2) When a child device changes its parent node and the route is changed (3) When sending all upstream messages from the child device to the parent device (4) Periodic transmission from the child device to the parent device (5) Combination of (1) to (4) above

[0266] ● Parent unit operation (receives child unit ID and wireless method) Figure 51 shows a situation in which the second collection device 20, upon receiving an upstream message from the second child device 20b, registers the wireless method bitmap and the intermediate nodes to be used for the downstream message to the second child device 20b in the intermediate 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 child device 20b, the second downstream route construction unit 320 obtains the wireless method and intermediate nodes from the Hop-by-Hop extension header, and creates a wireless method bitmap and source routing header addressed to the second child device 20b. The second collection device 20 registers the information of the source routing header and the wireless communication method bitmap in the route 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 20b.

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

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

[0270] When the second collection device 20 sends a downstream message addressed to the second child device 20b, if the second child 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 child device 20b.

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

[0272] In FIG. 52, the second handset 20 rIt is assumed that the first handset 10f and the second handset 20l have completed the joining operation to the communication system 504. Second handset 20 r It is assumed that the wireless systems for transmission to the parent node of 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 (assignment of child device ID and wireless method) The second child device 20r, via the multi-hop communication unit 340, writes identifier: 1 and ID: 20r of the second child device 20r 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, and transmits an upstream message to the parent node, the second child device 20l.

[0274] The second slave device 20l, which receives an upstream message from the second slave device 20r to the second collection device 20, writes identifier: 0 and ID: 20l of the second slave device 20l in the Hop-by-Hop extension header via 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 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 via the first multi-hop communication unit 301, and transmits the upstream message to the parent node, the second slave device 20b.

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

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

[0278] ● Parent unit operation (receives child unit ID and wireless method) Figure 53 shows a situation in which the second collection device 20, upon receiving an upstream message from the second child device 20r, registers the wireless method bitmap and the intermediate nodes to be used for the downstream message to the second child device 20r in the intermediate 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 child device 20r, the second downlink route construction unit 320 obtains the wireless method and intermediate nodes 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 child device 20r.

[0280] The second collection device 20 registers the information of the source routing header and the wireless communication method bitmap in the route 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] In the passing node information table 904, a destination ID, a source routing header, and a wireless communication system bitmap are registered.

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

[0283] In the wireless communication system bitmap, the wireless communication systems for the parent nodes of all the intermediate nodes from the second collection device 20 to the destination node are described in the order of the intermediate nodes.

[0284] Figure 53 shows a case where the second child device 20b and the second child device 20r send an upstream message of this embodiment to the parent node, and as a result, the second child device 20b and the second child device 20r are registered in the passing node information table 904. The transit node information table 904 can register the second slave unit 20r even in a state in which the second slave unit 20l and the first slave unit 10f have not transmitted an upstream message 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 child device 20r, if the second child device 20r is registered in the passing node information table 904, the multi-hop communication unit 340 uses the source routing header and wireless method bitmap of the second child device 20r.

[0286] As described above, when a slave unit in communication system 504 of embodiment 4 transmits or forwards an upstream message addressed to a master unit, the slave unit writes the slave unit's node ID and communication method in the upstream message so that the order in which the slave units are passed through can be determined. The parent unit stores the node ID and communication method described 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 unit that sent the upstream message addressed to the parent unit.

[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 on the downlink path. The communication system 504 of the fourth embodiment has a feature that, when receiving information about an uplink route including a wireless method, the information about the uplink route is used to construct a downlink route including a 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 transmits 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 transmits 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 sends the upstream message to the parent device, including the node's ID and the communication method with the parent node.

[0290] When a child device (child node) transmits or forwards an upstream message addressed to a parent device, it adds the child device's (child node's) ID and the communication method with the parent node to the upstream message. An upstream message addressed to the parent device notifies the parent device of the route (all the nodes through which the upstream message passed) and the communication method used in the upstream message transfer.

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

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

[0293] When the second downstream route construction unit 320 of the parent device receives an upstream message from a child node, which contains the ID of the via node through which the upstream message passed and the communication method of the via node, the second downstream route construction unit 320 records the ID of the via node and the communication method with the via node contained in the upstream 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 path to the child device sending the downstream message and the communication method with the via node.

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

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

[0297] Other examples 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 transmitted 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 transmitted and forwarded. For example, a method of adding it as an option header can be used.

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

[0300] Furthermore, in the embodiment, the upstream message of the embodiment may be transmitted instead of the notification message (DAO message (DAO-2)) transmitted when the child device completes the joining operation to the communication system 504. The second collection device 20 can generate 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] Embodiment 5. In the fourth embodiment, a method has been described in which, when sending and forwarding an upstream message, a child device assigns an identifier indicating the child device's ID and the communication method with the parent node, and the parent device uses the information in the upstream message to determine the downstream route and wireless method to be used for the downstream message.

[0302] In the fifth embodiment, differences from the fourth embodiment will be described. In this embodiment, a method for determining a downstream path and a wireless system when a slave unit ID is assigned but a communication system is not assigned when an upstream message is transmitted and transferred 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] ● Child unit operation (only child unit ID is assigned) FIG. 54 shows a situation in which the nodes through which the message has passed to the second collection device are added to the upstream message sent by the second slave device 20r by using the IPv6 Hop-by-Hop extension header.

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

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

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

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

[0309] ● Parent unit operation (receives only the child unit ID) Figure 55 shows a situation in which the second collection device 20, upon receiving an upstream message from the second child device 20r, registers the via nodes 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 child device 20r, the second downstream route construction unit 320 obtains the intermediate nodes from the Hop-by-Hop extension header and sorts them in reverse order to create a source routing header addressed to the second child device 20r.

[0311] The second collection device 20 establishes a source routing header by the second downstream path construction unit 320. Da's The information is registered in the transit node information table 905 as a source routing header addressed to the second child device 20r. When the second collection device 20 transmits a downstream message addressed to the second child device 20r, if the second child device 20r is registered in the passing node information table 905, the second collection device 20 uses the source routing header of the second child device 20r.

[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 transferring an upstream message addressed to a parent unit, the child unit of communication system 504 of the fifth embodiment writes the node ID of the child unit in the upstream message so that the order of the child units can be determined. The parent unit stores the ID of the node written in the upstream message in a memory or storage device, and uses the stored node ID to create a downstream message for the child unit that sent the upstream message addressed to the parent unit.

[0314] Summary of the fifth embodiment The communication system 504 of the fifth embodiment has a feature that, when information on an upstream route is received, the information on 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, the multi-hop communication unit 340 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) transmits or forwards an upstream message addressed to a parent device, it adds its own ID to the upstream message. An upstream message addressed to the parent device notifies the parent device of the route (all intermediate nodes) used in the message transfer.

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

[0319] When the second downstream 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 the via node information table 905 in association with the ID of the child node.

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

[0321] When creating a downstream message for a child node, the multi-hop communication unit 340 of the parent device refers to the IDs of the passed-through nodes listed in the passed-through node information table 905 to identify the passed-through nodes present on the path to the child device to which the downstream message is to be sent.

[0322] The multi-hop communication unit 340 of the parent device acquires the wireless system from the downlink route table 901 according to the ID of the transit node on the route. The multi-hop communication unit 340 of the parent device refers to the downstream route table 901 and identifies the communication method corresponding to the intermediate nodes present on the route to the child device to which the downstream message is to be sent. The multi-hop communication unit 340 of the master creates a downstream message including the IDs of the nodes to be passed through and the communication methods of the nodes to be passed through.

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

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

[0325] Other examples 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 provide information on the transmission and forwarding of 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 the upstream message is transmitted and forwarded, 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, the first PHY / MAC and the second PHY / MAC, are expressed by 0 or 1, but two or more types of wireless systems may be specified using multiple bits.

[0328] Also, the passed-through node information table 905 may be provided with an item of “wireless system bitmap” and may have the same format as the passed-through node information table 904 . When the multi-hop communication unit 340 of the parent device refers to the downlink route table 901 to identify the communication method of the node, the multi-hop communication unit 340 writes the identified communication methods in order to the "wireless method bitmap". As a result, a "wireless method bitmap" similar to the transit node information table 904 can be created.

[0329] Although a plurality of configurations have been described above, two or more of these configurations may be combined for implementation. Alternatively, one of these configurations 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 necessary. [Explanation of symbols]

[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 via node information table, 905 via node information table, 922 auxiliary storage device, 930 input interface, 940 output interface.

Claims

1. In a slave device connected to a wireless mesh network constructed based on the first rank value calculated by the first protocol, A communication device that receives one or more control messages from one or more neighboring nodes, the control messages including route information including rank information of the node; 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 a 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 an ID of the parent node and the second rank value calculated using the rank information of the parent node in a route table; a multi-hop communication unit that creates a notification message notifying the ID of the parent node recorded in the route table and transmits the notification message to a parent device; A sub-unit equipped with the above.

2. the protocol determination unit determines to perform processing based on a first protocol on the rank information; The slave device according to claim 1, wherein the upstream route construction unit calculates a first rank value using the rank information based on the first protocol based on the judgment result of the protocol judgment unit, and records the first rank value calculated using the rank information of the parent node in the route table.

3. The rank information includes at least one of first rank information and second rank information, the first rank information includes a first rank value and a first minimum increase value; The slave unit according to claim 1 or 2, wherein the second rank information includes a second rank value and a second minimum increase value.

4. The communication device receives, as the control message, from one node, A first control message including the first rank information of a node that transmits the control message; and receiving a second control message including the second rank information of the node that transmitted the control message; The upward path construction unit is a first upstream path construction unit that calculates the first rank value based on the first rank information of the source node; a second upstream path construction unit that calculates the second rank value based on the second rank information of the source node; 4. The handset according to claim 3, further comprising:

5. The upward path construction unit is The slave unit according to claim 3, further comprising a protocol conversion unit which, when receiving from one node only a first control message including first rank information of a source node of the control message, calculates a second rank value by weighting all hops from the parent unit to the slave unit, and, when receiving from one node only a second control message including second rank information of a source node of the control message, calculates a first rank value based on the number of hops in the route.

6. The slave unit according to claim 1 or 2, wherein when calculating the second rank value, the upstream route construction unit calculates the second rank value by weighting so that the second rank value differs when a different communication method is used.

7. the route information includes a number of consecutive routes of the second communication method in a route from a parent device, The slave unit according to claim 1 or 2, wherein the upstream path construction unit selects a parent node based on the consecutive number when there are a plurality of nodes having the same second rank value.

8. the route information includes whether or not there is a node on a route from a parent device that is capable of only the first communication method, The slave device according to claim 1 or 2, wherein when there are multiple nodes with the same second rank value, the upstream route construction unit selects a parent node based on whether or not there is a node that is capable of only the first communication method.

9. The path information includes a type of a parent node or a communication method of a parent node, The child device described in claim 1 or 2, wherein the upstream route construction unit selects the second communication method as the communication method with the parent node only if the parent node and the child node correspond to the first communication method and the second communication method, respectively, by referring to the type of parent node and the type of child node, or the communication method of the parent node and the communication method of the child node, and records the communication method with the parent node in the route table.

10. The child device according to claim 9 , wherein the multi-hop communication unit transmits the notification message to the parent device, the notification message including a communication method with the parent node recorded in the route table.

11. the communication device receives a downstream message including an ID of a node present on a path to a child device that transmits the downstream message and a communication method with the node; The child device according to claim 1 or 2, wherein the multi-hop communication unit identifies a child node's ID and a communication method with the child node by referring to the node's ID and the communication method with the node contained in the downstream message, and forwards the downstream message to the child node.

12. when creating an upstream message addressed to a parent device and transmitting the upstream message to the parent device, the multi-hop communication unit creates an upstream message including an ID of the node itself and a communication method with the parent node, and transmits the upstream message to the parent device; The child device according to claim 1 or 2, wherein when the multi-hop communication unit receives the upstream message and forwards it to the parent device, the multi-hop communication unit transmits the upstream message to the parent device, including the ID of the node itself and the communication method with the parent node.

13. When creating an upstream message addressed to a parent device and transmitting the message to the parent device, the multi-hop communication unit creates an upstream message including an ID of the node itself and transmits the message to the parent device; 3. The slave device according to claim 1, wherein, when the multi-hop communication unit receives the upstream message and transfers it to the master device, the multi-hop communication unit transmits the upstream message to the master device while describing an ID of the node itself in the upstream message.

14. In a parent device connected to a wireless mesh network in which multiple child devices serve as nodes, a communication device that receives a notification message from a child node, the notification message notifying the parent node ID and a communication method with the parent node; a downstream route construction unit that records in a downstream route table a parent node ID, a communication method with the parent node, and the child node ID included in the notification message in association with each other; a multi-hop communication unit that refers to the downlink route table, identifies one or more nodes that exist on a route to a child device that transmits a downlink message, and creates a downlink message that includes an ID of the node and a communication method with the node; A parent unit equipped with

15. the downlink route construction unit records the first rank information and the second rank information in a rank table; The parent device according to claim 14, wherein the multi-hop communication unit creates a first control message including the first rank information and a second control message including the second rank information, and transmits the first control message and the second control message to a neighboring node.

16. when the downstream route construction unit receives an upstream message from a child node, the downstream route construction unit records the ID of the via node and the communication method of the via node described in the upstream message in a via node information table in association with the ID of the child node; The parent device of claim 14 or 15, wherein when creating a downstream message for the child node, the multi-hop communication unit refers to the ID of the via node and the communication method of the via node listed in the via node information table, and creates a downstream message including the ID of the via node and the communication method with the via node present on the path to the child device sending the downstream message.

17. when the downstream route construction unit receives an upstream message from a child node, the downstream route construction unit records the ID of the via node described in the upstream message in a via node information table in association with the ID of the child node; The parent unit of claim 14 or 15, wherein when creating a downstream message for the child node, the multi-hop communication unit refers to the ID of the via node listed in the via node information table to identify the via node on the route to the child node, refers to the downlink route table to identify the communication method of the via node corresponding to the via node on the route to the child node, and creates a downstream message including the ID of the via node and the communication method of the via node.

18. A master unit that transmits a downstream message including a node ID and a communication method with the node; a child device that receives the downstream message, identifies a child node ID and a communication method with the child node by referring to a node ID and a communication method with the node included in the downstream message, and transfers the downstream message to the child node; A communication system comprising:

19. When transmitting and transferring an upstream message addressed to a parent device, the child device writes in the upstream message the node ID and the communication method of the child device, 20. The communication system according to claim 18, wherein the parent device stores the node ID and communication method described in the upstream message, and creates a downstream message using the stored node ID and communication method.

20. When transmitting and transferring an upstream message addressed to the parent device, the child device writes the node ID of the child device in the upstream message, 20. The communication system according to claim 18, wherein the master unit stores an ID of a node written in the upstream message, and creates a downstream message using the stored ID of the node.

21. the parent device and the child device are connected to a wireless mesh network capable of communicating with each other using a first protocol and a second protocol; 20. The communication system according to claim 18, wherein the master unit and the slave unit communicate only according to the second protocol by stopping communication according to the first protocol.

22. A communication method for a slave device connected to a wireless mesh network established based on a first rank value calculated by a first protocol, comprising: A communication device receives one or more control messages from one or more neighboring nodes, the control messages including route information including rank information of the node; a protocol determination unit determines to perform a process based on a second protocol on the rank information; an upstream route construction unit calculates a second rank value using the rank information based on the second protocol based on a determination result of the protocol determination unit, selects one node from among the one or more neighboring nodes as a parent node based on the one or more second rank values, and records an ID of the parent node and the second rank value calculated using the rank information of the parent node in a route table; A communication method in which a multi-hop communication unit creates a notification message notifying an ID of the parent node recorded in the route table and transmits the notification message to a parent device.

23. A communication method for a master device connected to a wireless mesh network in which multiple slave devices serve as nodes, comprising: A communication device receives, from a child node, a notification message notifying an ID of a parent node and a communication method with the parent node; a downstream route construction unit that records in a downstream route table the parent node ID, the communication method with the parent node, and the child node ID included in the notification message in association with each other; A communication method in which a multi-hop communication unit refers to the downstream route table to identify one or more nodes on a route to a child device sending a downstream message, and creates a downstream message including the node ID and a communication method with the node.

24. A slave connected to the wireless mesh network constructed based on the first rank value calculated by the first protocol, the slave receiving one or more control messages including route information including rank information of the node from one or more neighboring nodes. a protocol determination process for determining whether to perform a process based on a second protocol on the rank information; an upstream route construction process for calculating a second rank value using the rank information based on the second protocol based on a determination result of the protocol determination process, selecting one node from the one or more neighboring nodes as a parent node based on the one or more second rank values, and recording the ID of the parent node and the second rank value calculated using the rank information of the parent node in a route table; a multi-hop communication process of creating a notification message notifying the ID of the parent node recorded in the route table and transmitting the message to the parent device; A program that executes the following.

25. A parent device connected to a wireless mesh network with multiple child devices as nodes. A communication process of receiving, from a child node, a notification message notifying an ID of a parent node and a communication method with the parent node; In a parent device connected to a wireless mesh network in which a plurality of child devices serve as nodes, a communication device receives a notification message from a child node, the notification message notifying the child node of an ID of the parent node and a communication method with the parent node, a downstream route construction process for recording in a downstream route table a parent node ID, a communication method with the parent node, and a child node ID included in the notification message in association with each other; a multi-hop communication process of referring to the downlink route table, identifying one or more nodes existing on a route to a child device that transmits a downlink message, and creating a downlink message including an ID of the node and a communication method with the node; A program that executes the following.

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