WO2015015562A1 - Wireless data collection system, and wireless data collection method - Google Patents

Abstract

The present invention is capable of coping with an early stage fault in a communication path. A wireless data collection system (1) comprising a plurality of wireless sensor terminals (10) and a server (30) that acquires data from the plurality of wireless sensor terminals. If a polling packet is received from the server (30), the plurality of wireless sensor terminals (10) broadcast prescribed terminal information pertaining to a terminal in question to the wireless sensor terminals surrounding the terminal in question. The wireless sensor terminals (10) receive and hold prescribed terminal information which has been broadcast from the other wireless sensor terminals surrounding the terminal in question and pertains to the other wireless sensor terminals, and send the prescribed terminal information pertaining to the terminal in question and the prescribed terminal information pertaining to the other wireless sensor terminals to the server (30) as a polling response to the polling packet.

Description

Wireless data collection system and wireless data collection method

The present invention relates to a wireless data collection system and a wireless data collection method.

A system that automatically collects energy monitoring data in homes, buildings, factories, etc. by multi-hop communication of a large number of wireless sensor terminals has attracted attention. By connecting sensor terminals that detect power consumption and the like through a wireless multi-hop network, it is not necessary to perform cabling or the like, so that a data collection system can be constructed relatively easily.

However, wireless communication has a drawback in that the communication state changes from moment to moment due to changes in obstacles on the communication path and is not stable. In view of this, there has been proposed a technique for increasing the reliability of data collection by appropriately changing a communication path used for multi-hop communication.

In one conventional technique, data is exchanged between wireless communication terminals, and a routing table is created by collecting the results of data exchange at a higher node (Patent Document 1). In the prior art, when a communication failure occurs and polling fails, another route is selected by referring to the routing table, and polling from another route is attempted. Thereby, in the prior art, even when a communication failure occurs, polling can be performed by creating an alternative route in the upper node.

Japanese Patent Application Laid-Open No. 2011-4096

However, for example, when a construction work or the like starts or a new structure or vehicle is placed between the wireless sensor terminals for a long period of time, the surrounding environment of the wireless sensor terminal changes greatly. When the surrounding environment of a wireless sensor terminal changes greatly, a communication failure may occur in a plurality of links of a certain wireless sensor terminal. When a communication path failure occurs in a plurality of links of a wireless sensor terminal, it is necessary to perform polling from the parent node a plurality of times while changing the communication path, which may take a long time for recovery.

Especially when a wireless multi-hop network is used, a large delay occurs in proportion to the number of multi-hop hops. Therefore, it is necessary to estimate the time required for recovery from a failure according to the number of hops and the number of retries. As a result, for example, the number of terminals that can be managed by the system may be limited, or it may be difficult to recover within a fixed period. When the time required for recovery is too long or when it is difficult to predict, it is not convenient for a person who uses sensor data, and it is difficult to use it for a system that needs to collect data within a predetermined time.

In addition, in the prior art, an event can be issued from the wireless sensor terminal in order to update the routing information, but the management function of each wireless sensor terminal is controlled while suppressing radio wave interference in the wireless data collection system. In order to simplify, it is desirable not to perform communication other than polling as a starting point.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a wireless data collection system and a wireless data collection method capable of improving usability. Another object of the present invention is to provide a wireless data collection system and a wireless data collection method capable of handling a communication failure with a certain wireless sensor terminal in a relatively short time. .

In order to solve the above-described problem, a wireless data collection system according to the present invention is a wireless data collection system including a plurality of wireless sensor terminals and a server that acquires data from the plurality of wireless sensor terminals. When the sensor terminal receives the polling packet from the server, the sensor terminal broadcasts predetermined terminal information about the own terminal to wireless sensor terminals around the own terminal, and other wireless sensors broadcast from other wireless sensor terminals around the own terminal. Predetermined terminal information related to the terminal is received and held, and the predetermined terminal information related to the own terminal and the predetermined terminal information related to another wireless sensor terminal are transmitted to the server as a polling response to the polling packet.

According to the present invention, when receiving a polling packet, the wireless sensor terminal can broadcast and hold predetermined terminal information to other wireless sensor terminals in the vicinity. When responding to the polling packet, the wireless sensor terminal can transmit predetermined terminal information about the terminal itself and predetermined terminal information received from surrounding wireless sensor terminals to the server.

1 is an overall configuration diagram of a wireless data collection system. Explanatory drawing which shows the outline | summary of a radio | wireless-type data collection method. The block diagram of each apparatus which a wireless data collection system contains. (A) shows the structural example of the database which manages the data collected regularly from each wireless sensor terminal, (b) shows the structural example of the link database which manages the communication state between wireless sensor terminals. (A) shows the structural example of the database which manages routing, (b) shows the structural example of the database which manages the information of apparatuses, such as a sensor terminal and a gateway. (A) shows a configuration example of a database that manages node-specific information, and (b) shows a configuration example of a database that manages data related to neighboring terminals as “peripheral terminals”. The structural example of the database which manages the data collected regularly is shown. (A) is a configuration example of a common header, (b) is a configuration example of a polling packet, (c) is a configuration example of a polling response packet, (d) is a configuration example of a packet for notifying information, (E) shows a configuration example of an inquiry packet. The flowchart which shows the process which collects data regularly. The flowchart which shows a polling process. The flowchart which shows the packet communication process which receives and responds to a packet. The flowchart of the process which receives a polling packet. The flowchart of the process which receives a polling response packet. The flowchart of the process which receives an information notification packet. The flowchart of the process which receives an inquiry packet. The sequence diagram which shows the data collection method. The sequence diagram which shows the method of making an inquiry to a failure occurrence terminal from the adjacent terminal which can communicate with a failure occurrence terminal, and broadcasting information from a failure occurrence terminal to a peripheral terminal.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this embodiment, as will be described in detail below, each wireless sensor terminal can broadcast predetermined terminal information related to its own terminal before polling response, and predetermined terminal information related to other wireless sensor terminals received last time. And predetermined terminal information about the own terminal to the server. For a failed terminal, data is not collected directly from other routes, but by giving a trigger to the failed terminal from an adjacent terminal that can communicate with the failed terminal, the predetermined terminal information is obtained from the failed terminal. Broadcast. Therefore, in the present embodiment, the data detected by the faulty terminal can be collected in the next data collection cycle at the latest, and can be recovered in a short time without depending on the number of pops. Since the failure occurrence terminal is a terminal that has failed in polling communication, it may be called a polling failure terminal.

In this embodiment, for example, it can be expressed as follows.

A plurality of wireless sensor terminals whose communication timing is controlled by polling, a data collection server that periodically polls each wireless sensor terminal to collect data, each wireless sensor terminal, and the data collection server A data collection method in a wireless multi-hop communication polling system including a gateway that relays communication with

When the data collection server fails to collect data from a faulty terminal among the wireless sensor terminals, an inquiry is made to an adjacent terminal capable of directly communicating with the faulty terminal among the wireless sensor terminals. Sending a polling packet with a flag set;

The adjacent terminal that has received the polling packet with the inquiry flag set transmits an inquiry packet to the faulty terminal;

Receiving the inquiry packet and broadcasting the information notification packet by the failed terminal;

The neighboring terminal that has received the information notification packet transmits a polling response packet including data in the information notification packet to the data collection server;

The data collection server that has received the polling response packet, based on the polling response data and adjacent terminal data, manages the data collected periodically and the communication state between each wireless sensor terminal Updating a link database for managing
A data collection method comprising:

This embodiment can be further expressed as follows.

The data collection server transmits a polling packet including an information notification packet transmission code defining a transmission method of the information notification packet to the wireless sensor terminal,

The wireless sensor terminal that has received the polling packet broadcasts an information notification packet according to the information notification packet transmission code or broadcasts an information notification packet in which a save flag for preferentially storing the notified information is set. Selecting either method of not transmitting an information notification packet,

The neighboring terminal that has received the information notification packet updates the neighboring terminal database for managing neighboring terminals when the saving flag is set, or when the saving flag is not set. Selecting whether to update the neighboring terminal database based on a predetermined criterion or not to update the neighboring terminal database;

If each of the wireless sensor terminals has updated the adjacent terminal database since the previous polling, the wireless sensor terminal sends a polling response packet including the data of the adjacent terminal database to the data collection server when receiving the current polling packet. Sending, and

The data collection server that has received the polling response packet reflects the content of the adjacent terminal data in the link database;
A wireless multi-hop communication polling system.

According to the present embodiment, even when the surrounding environment of the wireless sensor terminal changes greatly and a communication path failure occurs in a plurality of links, data can be acquired from the failed terminal in a short time and recovered quickly. Furthermore, according to the present embodiment, recovery from failure of data collection due to communication failure can be performed only by communication starting from polling. For this reason, it is not necessary to issue an event from the wireless sensor terminal, and radio wave interference in the data collection system can be suppressed.

FIG. 1 shows an overall configuration of a wireless data collection system 1 according to the present embodiment. The system 1 collects sensing data from each wireless sensor terminal 10 by polling using wireless multi-hop communication.

In the present system 1, for example, a plurality of wireless sensor terminals 10 are distributed in a region such as a residential area, an office building area, an industrial park, or a facility such as a factory or a building. The data collection server 30 collects regularly collected data measured by the sensor unit 15 or the like by the wireless sensor terminal 10 arranged at each measurement point via the communication network 40. Regular collection data (also called regular collection value or regular collection information) is an example of “data detected by a wireless sensor terminal”.

The gateway 20 provided between the data collection server 30 and each wireless sensor terminal 10 receives periodic collection data from each wireless sensor terminal 10 using wireless multi-hop communication, and sends the received data to the data collection server 30. send. The data collection server 30 can manage a plurality of gateways 20, and each gateway 20 can accommodate a plurality of wireless sensor terminals 10. That is, the data collection server 30 can manage a plurality of sensor networks.

The wireless sensor terminal 10 periodically measures and holds data such as power consumption and power generation, for example. The information to be measured is not limited to information about power. For example, weather information such as temperature, humidity, and atmospheric pressure, social consumption data such as water and sewage usage and gas usage, or various controls such as temperature, pressure, flow rate, and speed It may be the information.

When the wireless sensor terminal 10 receives the information acquisition request by polling from the data collection server 30, the wireless sensor terminal 10 transmits the periodically collected information periodically measured to the upper node by wireless communication. Furthermore, the wireless sensor terminal 10 has a relay function of transferring packets transmitted from the wireless sensor terminal 10 and the gateway 20 toward another wireless sensor terminal 10 that is a destination.

The gateway 20 has a function of relaying communication between each wireless sensor terminal 10 and the data collection server 30 by absorbing differences in communication media and protocols.

The communication network 40 connects the communication between the gateway 20 and the data collection server 30 wirelessly or by wire, and is configured as Ethernet (registered trademark) or Internet, for example. Hereinafter, it is referred to as a network 40.

The data collection server 30 transmits an information acquisition request from the network 40 to the wireless sensor terminal 10 via the gateway 20 in order to periodically acquire the periodically collected information from each wireless sensor terminal 10. The data collection server 30 receives the regularly collected information transmitted as a response to the information acquisition request by the wireless sensor terminal 10, and accumulates and manages the received information.

In FIG. 1, the wireless communication paths are distinguished from solid lines and broken lines. A communication path indicated by a solid line indicates that the communication path is used as a communication path that enables direct wireless communication. A communication path indicated by a broken line indicates that wireless direct communication is possible, but it is not used as a communication path. Hereinafter, for a certain wireless sensor terminal 10, the wireless sensor terminal 10 or the gateway 20 that can directly communicate wirelessly is referred to as an adjacent terminal. An adjacent terminal is an example of a “peripheral terminal”.

In this embodiment, low-speed wireless communication represented by specific low-power wireless is assumed as wireless communication between the wireless sensor terminals 10 and wireless communication between the wireless sensor terminal 10 and the gateway 20. However, the present invention is not limited to this, and other wireless systems such as a wireless LAN standard represented by IEEE802.11a / b / g / n, IEEE802.15.4, Bluetooth (registered trademark), or UWB may be used.

The outline of the data collection method will be described with reference to FIG. Details of the processing contents will be described later. The data collection server 30 polls the wireless sensor terminal 10 in a predetermined order (for example, in the order of node identification numbers) and requests transmission of periodic collection information. Hereinafter, the wireless sensor terminal 10 may be abbreviated as the terminal 10 in some cases. The wireless sensor terminal 10 may be abbreviated as the wireless terminal 10.

Here, it is assumed that polling to a certain terminal 10 (# 5) has failed due to the presence of an obstacle CF (S1). The data collection server 30 tries to communicate from the gateway 20 to the polling target terminal 10 (# 5) via the terminal 10 (# 2), but between the terminal 10 (# 2) and the terminal 10 (# 5). If an obstacle CF such as a vehicle is present, communication from the terminal 10 (# 2) to the terminal 10 (# 5) cannot be performed. Therefore, if the data collection server 30 cannot receive the response from the terminal 10 (# 5) within a certain time, it determines that a failure has occurred.

In the present embodiment, since the following specific processing is executed, even when the occurrence of a failure of the terminal 10 (# 5) is detected, the data collection server 30 does not need to take immediate action for recovery. Information collection can be continued.

Suppose that the next polling target terminal is the terminal 10 (# 7). The data collection server 30 determines whether the next polling target terminal 10 (# 7) is an adjacent terminal capable of wireless communication with the faulty terminal 10 (# 5). When the data collection server 30 determines that the next polling target terminal 10 (# 7) is not an adjacent terminal of the faulty terminal 10 (# 5), the data collection server 30 transmits a normal polling packet to the terminal 10 (# 7). (S2). The polling packet reaches the terminal 10 (# 7) from the gateway 20 via the terminal 10 (# 3). When the terminal 10 (# 7) receives the polling packet, the terminal 10 (# 7) broadcasts predetermined terminal information (information notification packet 54, which will be described later) related to the terminal 10 (# 7) to the surroundings (S3). Information broadcast from the terminal 10 (# 7) is received by the terminal 10 (# 6) and the terminal 10 (# 10) and stored when a predetermined criterion is satisfied. After broadcasting the information, the terminal 10 (# 7) returns a polling response including the periodically collected information detected by the terminal (# 7) to the data collection server 30.

It is further assumed that the next polling target terminal is the terminal 10 (# 1). When the data collection server 30 determines that the next polling target terminal 10 (# 1) is an adjacent terminal of the faulty terminal 10 (# 5), the data collection server 30 transmits a polling packet including inquiry information to the terminal 10 (# 1). (S4).

The terminal 10 (# 1) inquires of the failure occurrence terminal 10 (# 5) about the state by wireless communication in accordance with the inquiry information included in the polling packet (S5). When the failure occurrence terminal 10 (# 5) receives the inquiry request from the terminal 10 (# 1), it broadcasts predetermined terminal information (information notification packet) related to the own terminal (# 5) to the surroundings (S6). That is, the inquiry request is an opportunity for the faulty terminal 10 (# 5) to simultaneously transmit information including the state of the own terminal to the other terminals 10 in the vicinity.

In this example, information broadcast from the faulty terminal 10 (# 5) is received by the terminals 10 (# 1), 10 (# 4), 10 (# 6), 10 (# 8), and 10 (# 9). Is done.

When the terminal 10 (# 1) as the inquiry source receives the information from the faulty terminal 10 (# 5), it returns a polling response including the update information to the data collection server 30 (S7).

The update information includes, for example, regular collection information measured by the own terminal 10 (# 1) and information received from the faulty terminal 10 (# 5) (periodic collection information measured by the faulty terminal 10 (# 5)). And information indicating the wireless communication state between other terminals measured in the previous periodic collection information collection cycle.

As will be described in detail later, when each terminal 10 receives a polling packet from the data collection server 30, it broadcasts information about its own terminal to the surroundings before returning a polling response. Other terminals around that have received the broadcast information hold the power value at the time of information reception as information indicating the state of wireless communication (communication quality). And when these other terminals receive the polling packet to an own terminal, they include the information which shows the state of radio | wireless communication with a surrounding terminal in a polling response.

Thus, in the present embodiment, the data collection server 30 does not need to immediately address the recovery of the failure terminal 10 (# 5) even when there is the failure terminal 10 (# 5) from which the periodic collection information cannot be obtained. Recovery of the faulty terminal 10 (# 5) can be attempted while continuing normal information collection processing.

The data collection server 30 requests an inquiry to the faulty terminal 10 (# 5) when transmitting a polling packet to the adjacent terminal 10 (# 1) that can wirelessly communicate with the faulty terminal 10 (# 5) ( S4). The adjacent terminal 10 (# 1) inquires of the failure occurrence terminal 10 (# 5) about the state instead of the polling packet (S5). Upon receiving this inquiry, the faulty terminal 10 (# 5) broadcasts the regularly collected information detected by the own terminal (# 5) to the neighboring terminal 10 (# 1) as the inquiry source (S6).

The adjacent terminal 10 (# 1) receives the periodic collection information detected by the own terminal (# 1), the periodic collection information detected by the failure occurrence terminal 10 (# 5), and terminals around the own terminal (# 1). The reception strength (communication state) of the received information is returned to the data collection server 30 as a polling response from the own terminal 10 (# 1) (S7). As a result, the data collection server 10 can acquire information from the failure occurrence terminal 10 (# 5) while continuing to obtain normal periodic collection information, and the failure collection terminal 10 (# 5) Recovery can be performed. Here, the recovery of the terminal means that the regularly collected information is acquired from the faulty terminal.

A configuration example of each of the devices 10, 20, and 30 constituting the system 1 will be described with reference to the block diagram of FIG. The data collection server 30, the gateway 20, and the terminal 10 will be described in this order. In the drawing, names of the respective parts are omitted as appropriate.

The data collection server 30 is an example of a “server” and includes, for example, a microprocessor (CPU) 31, a memory 32, an auxiliary storage device 33, an input device 34, an output device 35, and a communication I / F unit 36.

The memory 32 stores, for example, a periodic collection program 321 for periodically collecting data from each terminal 10 and a packet communication program 322 for controlling packet transmission / reception. The auxiliary storage device 33 stores, for example, a periodic collection value database 331, a link database 332, a routing database 333, and a device information database 334. A configuration example of these databases will be described later.

The input device 34 is a device for the system administrator to input information to the data collection server 30 and is configured by appropriately using, for example, a keyboard, a pointing device, a tablet, a voice input device, a line-of-sight detection device, a motion detection device, or the like. Is done. The output device 35 is a device that is used by the system administrator to extract information from the data collection server 30, and is configured using, for example, a display, a printer, a voice synthesizer, or the like as appropriate.

The periodic collection program 321 transmits a polling packet 52 (described later in FIG. 8) to each terminal 10 in order to periodically collect data from each terminal 10 under management. If the data collection from the terminal 10 fails, the periodic collection program 321 sends an inquiry packet 55 for requesting an inquiry from the adjacent terminal to the failed terminal when transmitting the polling packet 52 to the terminal adjacent to the failed terminal. (Described later in FIG. 8). The operation of the periodic collection program (which may be referred to as a data collection program) 321 will be described with reference to FIGS.

The packet communication program 322 is a program that transmits / receives data to / from other apparatuses 10 and 20 via the network 40 and the communication I / F unit 36. The packet communication program 322 of the data collection server 30 generates a polling packet 52 having a predetermined structure and transmits it to the terminal 10 to be polled, or periodically based on the contents of the packet received from each terminal 10 via the gateway 20. The collection value database 331, the link database 332, and the adjacent terminal database 223 are updated. The basic operation of the packet communication program is common to the program 322 of the data collection server 30, the program 221 of the gateway 20, and the program 122 of the terminal 10, and will be described later with reference to FIGS.

The regular collection value database 331 is a database for managing information collected by each terminal 10 for each time series, and a configuration example thereof will be described later with reference to FIG.

The link database 332 is a table for creating a routing table, and manages the state of the radio links of the terminal 10 and the gateway 20. A configuration example of the link database 332 will be described later with reference to FIG.

The routing database 333 is a database that manages the routing table of the communication path, and its configuration example will be described later with reference to FIG.

The device information database 334 is a database that manages device information of the terminal 10 and the gateway 20, and a configuration example thereof will be described later with reference to FIG.

Note that the data collection server 30 may be provided on one computer, or may be configured to realize the function as the data collection server 30 by cooperation of a plurality of computers. The data collection server 30 may be provided on a virtual machine. Further, an operation terminal may be connected to the data collection server 30, and the system administrator may use the data collection server 30 using the operation terminal.

A configuration example of the gateway 20 will be described. The gateway 20 includes, for example, a CPU 21, a memory 22, a display unit 23, an auxiliary storage device 24, a communication I / F 25, a wireless processing unit 26, and a wireless communication antenna 27. In the memory 22, for example, a packet communication program 221, a node specific information database 222, and an adjacent terminal database 223 are stored.

The display unit 23 is a device for displaying the state of the gateway 20 (eg, whether it is operating normally), and includes, for example, a liquid crystal display, an LED (Light Emitting Diode) lamp, and the like.

The packet communication program 221 relays a packet received by the gateway 20 from the network 40 or the wireless communication antenna 27 via the communication I / F 25 and the wireless processing unit 26 to the destination. The packet communication program 221 updates the adjacent terminal database 223 based on the received packet. The packet communication program 221 can be configured similarly to the packet communication program 322 of the data collection server 30 described above. The operation will be described later.

The node specific information database 222 is a database for managing information unique to each node such as a node ID (identifier, identification information) of the terminal 10 and a node ID specific to the gateway 20. An example of the configuration will be described later with reference to FIG.

The adjacent terminal database 223 is a database for managing information of the terminals 10 that can communicate directly by radio. An example of the configuration will be described later with reference to FIG.

A configuration example of the wireless sensor terminal 10 will be described. The terminal 10 includes, for example, a CPU 11, a memory 12, a display unit 13, an auxiliary storage device 14, a sensor unit 15, a wireless processing unit 16, and a wireless communication antenna 17. The display unit 13 is a device for displaying the state of the terminal 10 (eg, whether it is operating normally), and includes, for example, a liquid crystal display, an LED lamp, and the like. If neither the display unit 23 of the gateway 20 nor the display unit 13 of the terminal 10 is present, there is no problem in operation.

In the memory 12, for example, a periodic measurement program 121, a packet communication program 122, a periodic measurement value database 123, an adjacent terminal database 124, and a node specific information database 125 are stored.

The regular measurement program 121 is a program that stores data obtained from the sensor unit 15 in the regular measurement value database 123 at regular intervals.

The packet communication program 122 has a relay function for transmitting a packet received from another terminal (including a gateway) via the wireless communication antenna 17 and the wireless processing unit 16 toward the destination of the packet. Furthermore, the packet communication program 122 updates the periodic measurement value database 123 and the adjacent terminal database 124 according to the type of packet data. The packet communication program 122 can be configured similarly to the packet communication program 322 of the data collection server 30 described above. The operation will be described later.

The periodic measurement value database 123 manages the data obtained from the sensor unit 15 in association with the data detection time. An example of the configuration will be described later with reference to FIG.

The adjacent terminal database 124 is a database that manages information of terminals (including the gateway 20) that can communicate directly by radio, and can be configured in the same manner as the adjacent terminal database 223 of the gateway 20.

The node specific information database 125 is a database for managing information unique to a node such as the node ID of the terminal 10 and the node ID unique to the gateway 20, and is the same as the node specific information database 222 of the gateway 20.

The sensor unit 15 is configured as a power meter, a thermometer, a sunshine meter, a pressure gauge, a hygrometer, or the like, for example. The wireless sensor terminal 10 does not have to include the sensor body, and a configuration in which the separately provided sensor body and the terminal 10 are connected wirelessly or by wire may be used.

FIG. 4A shows an example of the regularly collected value database 331. The regular collection value database 331 stores, for example, a network ID, a regular collection number, a node ID 3311, a polling communication 3312, a regular collection value 3313, and a regular collection time 3314 in order to manage data collected from the terminal 10. The periodic collection value database 331 manages each information by a table uniquely determined from the values of the network ID and the periodic collection number. FIG. 4A shows a table structure when the network ID is “1” and the periodic collection number is “1”.

The node ID column 3311 manages an identifier that uniquely identifies the terminal 10 in each network ID. The identifier may call the identification information or the identification number.

The polling communication column 3312 manages information indicating the result of polling communication performed on the terminal 10. In the polling communication column 3312, an identifier indicating, for example, “success”, “failure”, or “not implemented” is set.

The periodic collection value column 3313 manages information acquired by the terminal 10 from the sensor unit 15. In the periodic collection value column 3313, for example, a numerical value representing the amount of power used in each power consumer (such as a home) is stored.

The regular collection time column 3314 manages the time when the terminal 10 acquires information from the sensor unit 15 (sensing data).

Note that the data collection server 30 can also manage a plurality of networks including one gateway 20 and a plurality of terminals 10. Therefore, the regular collection value database 331 prepares a table for each network ID and regular collection number in order to identify each network. The network ID of the periodic collection value database 331 is the same as the network ID of the node specific information databases 222 and 125.

The data collection server 30 acquires the regularly collected values in order from all the terminals 10 accommodated in each network identified by the network ID. Therefore, in the periodic collection value database 331, the periodic collection number is used to manage the number of regular collections from the terminal 10.

FIG. 4B shows an example of the link database 332. The link database 332 manages which node the terminal 10 and the gateway 20 can directly communicate with in order to create the routing database 333. Accordingly, the link database 332 stores, for example, the network ID, the reception node ID 3321, the transmission node ID 3322, the reception quality 3323, and the link update time 3324 in association with each other. The link database 332 manages each information by a table uniquely determined from the value of the network ID. The illustrated example shows a table whose network ID is “1”.

The receiving node ID column 3321 manages the receiving node ID indicating the node ID of the terminal 10 and the gateway 20 that have received wireless communication. The reception node ID corresponds to the node ID 3311 of the periodic collection value database 331.

The transmission node ID column 3322 manages the transmission node ID indicating the node ID of the terminal 10 and the gateway 20 transmitted by wireless communication. The transmission node ID corresponds to the node ID 3311 of the periodic collection value database 331.

The reception quality column 3323 records the quality when the packet transmitted from the transmission node is received by the reception node as the power value of the received radio wave. That is, the reception quality represents a received power value of radio waves when a wireless packet transmitted by the terminal 10 or the gateway 20 represented by the transmission node ID is received by the terminal 10 or the gateway 20 represented by the reception node ID.

The link update time column 3324 manages the link update time indicating the time when the terminal 10 or the gateway 20 indicated by the receiving node ID receives the wireless packet transmitted by the terminal 10 or the gateway 20 indicated by the sending node ID.

FIG. 5A shows an example of the routing database 333. The routing database 333 stores a communication path when the data collection server 30 communicates with each terminal 10. The routing database 333 manages each information by a table uniquely determined from the value of the network ID. The illustrated example shows a table whose network ID is “1”.

The routing database 333 manages, for example, a transmission node IP address column 3331, a destination node IP address column 3332, and a next relay destination node IP address column 3333 in association with each other.

The transmission node IP address column 3331 manages the transmission node IP address representing the IP address of the node that is the transmission source of the packet. The destination node IP address column 3332 manages the destination node IP address representing the IP address of the destination node that finally receives the packet. The next relay destination node IP address column 3333 is a node (terminal 10) selected as a communication relay destination when a packet cannot be transmitted directly from the source node indicated by the source node IP address to the destination node indicated by the destination node IP address. To manage the IP address of the relay destination node representing the IP address.

FIG. 5B shows an example of the device information database 334. The device information database 334 is a database for managing device information about the terminal 10 and the gateway 20. The device information database 334 stores, for example, a node ID 3341, a wireless MAC (Media Access Control Address) address 3342, an IP address 3343, and a subnet mask 3344. The device information database 334 manages each information by a table uniquely determined from the value of the network ID. The illustrated example shows a table when the network ID is “1”.

The node ID column 3341 manages a node ID that is an identifier for uniquely identifying the terminal 10 in each network ID. The node ID is the same as the node ID 3311 of the periodic collection value database 331.

The wireless MAC address column 3342 is an identifier that is uniquely assigned to a communication device, and manages a MAC address that is an identifier determined by IEEE or the like. The IP address column 3343 manages an IP address assigned to a communication device in network communication. The subnet mask column 3344 manages the subnet mask necessary for IP network communication.

FIG. 6A shows an example of the node specific information databases 222 and 125. Hereinafter, the node specific information database 222 (125) is shown. The code in parentheses corresponds to the node specific information database 125 of the terminal 10.

The node specific information database 222 (125) manages each item 2221 (1251) and its value 2222 (1252) related to the own device (gateway 20 or terminal 10) in association with each other. The item 2221 (1251) includes, for example, a node ID, a network ID, a wireless MAC address, an IP address, a subnet mask, a default gateway, and a server IP address.

The node ID is an identifier that uniquely identifies the terminal 10 or the gateway 20 in each network identified by the network ID, and is the same as the node ID 3311 of the periodic collection value database 331. The network ID is an identifier for identifying the networks when the data collection server 30 manages a plurality of networks. The wireless MAC address is an identifier uniquely assigned to the communication device, is an identifier determined by IEEE or the like, and is the same as the MAC address of the device information database 334.

The IP address is an IP address assigned to the communication device, and is the same as the IP address 3343 of the device information database 334. The subnet mask is a subnet mask necessary for IP network communication, and is the same as the subnet mask 3344 of the device information database 334. The default gateway is a default gateway necessary for IP network communication. The server IP address is an IP address assigned to the data collection server 30.

FIG. 6B shows an example of the adjacent terminal databases 223 and 124. Hereinafter, it is shown as the adjacent terminal database 223 (124). The code in parentheses corresponds to the adjacent terminal database 124 of the terminal 10.

The adjacent terminal database 223 (124) manages information on nodes (adjacent terminals) in which the own device (gateway 20 or terminal 10) can directly perform wireless communication. Thereby, in the communication between the terminal 10 and the data collection server 30, even when a failure occurs in the communication path, information can be collected from the failure occurrence terminal via the adjacent terminal. The adjacent terminal database 223 (124) includes, for example, the transmission node ID 2231 (1241), the reception quality 2232 (1242), the link update time 2233 (1243), the periodic collection value 2234 (1244) of the transmission source, and the collection time at the transmission source. 2235 (1245) is stored.

The transmission node ID column 2231 (1241) manages the transmission node ID which is an identifier representing the node ID of the terminal 10 that transmitted the packet or the node ID of the gateway 20 that transmitted the packet. The transmission node ID is the same as the transmission node ID 3322 of the link database 332.

The reception quality column 2232 (1242) is displayed when a wireless packet transmitted from the terminal 10 (or gateway 20) specified by the transmission node ID is received by the terminal 10 (or gateway 20) specified by the reception node ID. The reception quality representing the received power value of the radio wave is managed. The reception quality here is the same as the reception quality 3323 of the link database 332.

The link update time column 2233 (1243) indicates that a wireless packet transmitted from the terminal 10 (or gateway 20) specified by the transmission node ID is received by the terminal 10 (or gateway 20) specified by the reception node ID. Managing the reception time of. This reception time is stored in the field 2233 (1243) as the link update time. The link update time here is the same as the link update time 3324 of the link database 332.

The transmission source periodic collection value column 2234 (1244) manages data (periodic collection value) collected by the terminal 10 specified by the transmission node ID. The periodic collection time column 2235 (1245) at the transmission source manages the time when the terminal 10 specified by the transmission node ID acquires the regular collection value.

In the periodic collection value column 2234 (1244) of the transmission source and the periodic collection time column 2235 (1245) of the transmission source, communication between the data collection server 30 and the target terminal 10 fails, and the data collection server 30 detects that the target terminal 10 Even if the periodic collection value cannot be obtained from the adjacent terminal, the adjacent terminal adjacent to the target terminal holds the value.

Thereby, the data collection server 30 can collect the periodic collection value (periodic collection information) of the target terminal that failed last time from the adjacent terminal when polling the adjacent terminal.
However, when there are restrictions on the sizes of the memory 12 and the auxiliary storage device 14 of the terminal 10 or when it is desired to suppress communication traffic by reducing the size of data to be transmitted at once as much as possible, the periodic collection value column 2234 for transmission is used. (1244) and the periodic collection time column 2235 (1245) of transmission are also operable.

FIG. 7 shows an example of the periodic measurement value database 123. The regular measurement value database 123 is a database for storing data periodically acquired by the sensor unit 15 and includes, for example, a regular collection value 1231 field and a regular collection time field 1232.

The periodic collection value column 1231 manages information acquired by the terminal 10 by the sensor unit 15. The regular collection value here is the same as the regular collection value 3313 of the regular collection value database 331. The regular collection time column 1232 manages the time when the terminal 10 acquires information by the sensor unit 15. The regular collection time here is the same as the regular collection time 3314 of the regular collection value database 331.

A configuration example of a packet used in this embodiment will be described with reference to FIG. Details of the communication using the packet shown in FIG. 8 will be described later with reference to the flowcharts of FIGS.

FIG. 8A shows an example of the common header 51. The common header 51 is header information of an IP packet that is used in common among packets exchanged between the terminal 10, the gateway 20, and the data collection server 30.

The common header 51 includes, for example, a network ID 511, a transmission node IP address 512, a destination node IP address 513, a routing information length 514, a transmission node IP address 515, a next relay destination node IP address 516, a final destination node IP address 517, a packet An identification code 518 is included.

The network ID 511 is an identifier for specifying which of the plurality of networks managed by the data collection server 30, and is the same as the network ID of the node specific information databases 222 and 125.

The transmission node IP address 512 is information indicating the IP address of the transmission source node that first transmitted the packet. The destination node IP address 513 is information representing the IP address of the destination node that finally receives the packet. The routing information length 514 is information indicating the length of the communication path when the packet is transferred from the IP address 512 of the transmission source node to the IP address 513 of the destination node.

The transmission node IP address 515, the next relay destination node IP address 516, and the destination node IP address 517 represent routing information. The transmission node IP address 515 is information representing the IP address of the transmission source node of the packet, and has the same value as the transmission node IP address 512.

The next relay destination node IP address 516 is the IP address of the node selected as the relay destination of communication when communication from the transmission source node indicated by the transmission node IP address 515 to the destination node indicated by the destination node IP address 517 cannot be performed directly. Information representing an address. When the relay destination node passes through another node, the IP addresses of all the relay destination nodes that pass through are stored in the next relay destination node IP address 516 in the order of the communication path.

The destination node IP address 517 is information indicating the IP address of the destination node that finally receives the packet, and is the same as the destination node IP address 513. The packet identification code 518 is information representing the type of packet.

FIG. 8B shows an example of the polling packet 52. The polling packet 52 is a packet for the data collection server 30 to poll the terminal 10 in order to acquire a regularly collected value from the terminal 10. The polling packet 52 includes, for example, a common header 521, an information notification packet transmission code 522, an inquiry flag 523, and an inquiry destination node IP address 524.

The common header 521 is the same as the common header 51. The information notification packet transmission code 522 is information for controlling an information notification operation (broadcast operation) executed by the terminal 10 that has received the polling packet 52.

In accordance with the value of the information notification packet transmission code 522, the terminal 10 that has received the polling packet executes one of the following operations. In the first operation, the information of its own terminal is transmitted to the adjacent terminal as an information notification packet. In the second operation, the content of the information notification packet is preferentially stored in the other terminal 10 that has received the information notification packet. In the third operation, the information notification packet is not transmitted.

The inquiry flag 523 represents information for the terminal 10 that has received the polling packet 52 to determine whether to transmit an inquiry packet to an adjacent terminal. The inquiry destination node IP address 524 is information representing the IP address of the inquiry destination node of the inquiry packet when the inquiry packet is transmitted to the adjacent terminal.

The polling packet 52 may store a control instruction for instructing the terminal 10 to stop or restart the periodic collection by the sensor unit 15.

FIG. 8C shows an example of the polling response packet 53. The polling response packet 53 is a packet used when the terminal 10 that has received the polling packet 52 transmits information such as a regularly collected value to the data collection server 30. The polling response packet 53 includes, for example, a common header 531, polling response data code 532, polling response data length 533, polling response data 534, adjacent terminal data code 535, adjacent terminal data length 536, and adjacent terminal data 537. The

The common header 531 is the same as the common header 51. The polling response data code 532 is information indicating the type of polling response data 534. The polling response data length 533 is information indicating the length of the polling response data 534. The polling response data 534 is information representing data such as a regularly collected value and a regularly collected time of the terminal 10.

The adjacent terminal data code 535 is information indicating the type of the adjacent terminal data 537. The adjacent terminal data length 536 is information indicating the length of the adjacent terminal data 537. The adjacent terminal data 537 is information representing data such as reception quality and link update time of the adjacent terminals held in the adjacent terminal databases 223 and 124.

FIG. 8D shows an example of the information notification packet 54. The information notification packet 54 is a packet that is used by the terminal 10 that has received the polling packet 52 or the inquiry packet 55 to transmit predetermined terminal information about the own terminal to neighboring terminals. The information notification packet 54 includes, for example, a common header 541, an information notification priority storage flag 542, an information notification code 543, an information notification data length 544, and information notification data 545.

The common header 541 is the same as the common header 51. The information notification priority saving flag 542 is information for the terminal 10 (or gateway 20) that has received the information notification packet 54 to determine whether to save the information represented by the information notification data 545 or not.

Information notification code 543 is information indicating the type of information notification data 545. The information notification data length 544 is information indicating the length of the information notification data 545. The information notification data 545 represents information such as the regular collection value 1231 and the regular collection time 1232 stored in the regular measurement value database 123 of the terminal 10.

FIG. 8E shows an example of the inquiry packet 55. The inquiry packet 55 is a packet when the terminal 10 that has received the polling packet 52 responds according to the information of the inquiry flag 523, and includes a common header 551.

The common header 551 is the same as the common header 51. The inquiry packet 55 may include control information for designating the terminal 10 that is the inquiry destination as the number and type of data stored in the information notification packet 54 as a response to the inquiry.

FIG. 9 is a flowchart showing a process of collecting the regularly collected values from each terminal 10 executed by the regularly collecting program 321.

The periodic collection program 321 collects the regularly collected values detected at each terminal 10 at predetermined intervals by causing the data collection server 30 to sequentially perform polling processing (S12) on each terminal 10 under management.

When the polling communication to a certain terminal 10 fails, the periodic collection program 321 polls an adjacent terminal that is located around the failed terminal (failure-occurring terminal) and can communicate wirelessly with the failure-occurring terminal. At times, an inquiry packet 55 is transmitted. Thereby, in this embodiment, even when the environment of the wireless communication path changes and the acquisition of the periodic collection value fails, the periodic collection value can be acquired from the faulty terminal 10 only by the process starting from polling.

The regular collection program 321 first resets the regular collection number (S10), and then increments the regular collection number by one (S11). The periodic collection program 321 performs a polling process in which any one terminal is selected from the managed terminals 10 according to a predetermined selection criterion and the polling packet 52 is transmitted in order to acquire the regular collection value from the terminal 10. Perform (S12). The polling process will be described later with reference to FIG.

The periodic collection program 321 repeats the polling process in step S12 until the polling process for all the terminals 10 is performed (S13). The regular collection program 321 updates the routing table 333 based on the information in the polling response packet 53 received from the polling target terminal (S14).

The periodic collection program 321 determines whether a terminal (failure occurrence terminal) for which communication by polling has failed can be polled next time from a new wireless communication path (S15). If the periodic collection program 321 determines that there is a possibility of recovery for the terminal that has failed polling (S15: YES), after waiting for a certain time (S18), it returns to step S11, increments the periodic collection number by one, Regular collection. For example, when measuring power consumption, the next collection cycle is started after a predetermined time such as 30 minutes or 15 minutes has elapsed. In the new collection cycle, the neighboring terminal makes an inquiry to the failed terminal and acquires a regularly collected value from the failed terminal.

If the periodic collection program 321 is unable to create a new wireless communication path to the failed terminal and determines that there is no prospect of recovery of the failed terminal (S15: NO), the periodic collection program 321 starts from all adjacent terminals that can communicate with the failed terminal. It is determined whether the inquiry has been made (S16). If the periodic collection program 321 determines that the inquiry has been attempted from all the adjacent terminals (S16: YES), it issues an isolation warning to the terminal that has failed polling (S17). When there is an adjacent terminal that has not yet attempted an inquiry (S16: NO), in order to make an inquiry at the time of polling with the next periodic collection number, it waits for a certain time (S18) and returns to step S11.

Here, the update process of the routing table 333 in step S14 may be performed only when it can be determined that the link database 332 has changed from the adjacent terminal data 537 in the polling response packet 53. Thereby, the update frequency of the routing table 333 by the data collection server 30 can be reduced, and processing load can be reduced.

Examples of the case where it can be determined whether the link database 332 has changed based on the adjacent terminal data 537 include, for example, a case where a change of 3 dBm or more occurs in the reception quality, or a case where a terminal that has failed in polling is detected. it can.

An example of a method for updating the routing table 333 will be described. The periodic collection program 321 refers to the link database 332 to find, for example, the shortest path among a plurality of existing wireless communication path candidates, or to select a path with high reception quality, the number of hops and reception quality To create a new route.

As a method of issuing an isolation warning to the polling failure terminal in step S18, for example, there is a method of displaying a warning on the output device 35 or notifying the administrator of the data collection server 30 by e-mail or the like. For example, it is possible to propose a change of a wireless communication channel to be used or to prompt a field investigation by a maintenance staff by warning the administrator.

FIG. 10 is a flowchart showing details of the polling process described in step S12 in FIG.

As described with reference to FIG. 9, the polling process (S12) is a subroutine of the periodic collection program 321 and executes a normal polling process and a polling process for recovering a polling failure terminal.

The periodic collection program 321 first determines the terminal 10 to be polled (S120). The periodic collection program 321 checks whether there is a terminal that has failed in polling as an adjacent terminal of the polling target terminal (S121). That is, the periodic collection program 321 determines whether the polling target terminal is an adjacent terminal of the failed terminal.

If the periodic collection program 321 determines that the polling target terminal is an adjacent terminal of the failed terminal (S121: YES), it sets the inquiry flag 523 in the polling packet 52 (S122). Further, the periodic collection program 321 sets the information notification packet transmission code 522 of the polling packet 52 (S123). The periodic collection program 321 transmits the polling packet 52 generated in this way with the polling target terminal as the destination (S124).

The periodic collection program 321 waits for a predetermined time after the transmission of the polling packet 52, and determines whether the polling response packet 53 is received during the waiting or whether a timeout has occurred (S125).

The periodic collection program 321 updates the periodic collection value database 331 and the link database 332 with the data obtained from the polling response packet 53 when receiving the polling response packet 53 from the polling target terminal within a predetermined time. Thereby, the polling communication is successful (S126).

If the polling response packet 53 cannot be received from the polling target terminal within a certain time and a time-out occurs, the periodic collection program 321 assumes that polling communication has failed and cannot acquire data in the periodic collection value database 331. The fact is recorded (S127). In the next loop, the periodic collection program 321 sets an inquiry flag at the time of polling processing to the adjacent terminal of the polling failure terminal (S122).

Examples of criteria for determining a polling target terminal in step S120 include, for example, a node ID that is randomly selected from terminals that have not been polled, a node that has failed polling in the previous periodic collection number, and a node ID that is selected first. And so on.

Example of setting information notification packet transmission code 522 in step S123. For example, in a mode in which the information notification packet 54 is broadcasted or not transmitted at random, the amount of traffic is reduced, or information is recovered until a fixed periodic collection number is recovered after a communication path failure is recovered. A mode in which the notification priority storage flag 542 is set and the information notification packet 54 is transmitted can be set in the information notification packet transmission code 522.

FIG. 11 is a flowchart showing packet communication processing executed by the packet communication programs 322, 221 and 122. In the following description, the packet communication programs 322, 221 and 122 are abbreviated as packet communication programs. The packet communication program is executed by the server 30, the gateway 20, and the terminal 10, respectively, but the name of the device that executes the packet communication program is changed according to the characteristics of each process S23 to S26 described later. For example, the process of receiving a polling packet (S23), the process of receiving an information notification packet (S25), and the process of receiving an inquiry packet (S26) are mainly executed by the terminal 10, and thus focus on the terminal 10. explain. Since the process of receiving the polling response packet is executed by the data collection server 30, a description will be given focusing on the data collection server 30. The gateway 20 serves as a bridge between the data collection server 30 and each terminal 10 and may be described as being included in the terminal 10.

When the terminal receives the packet, the packet communication program confirms the network ID and the destination node IP address included in the common header of the packet. The packet communication program transfers the packet to the next relay terminal as necessary. When the destination of the received packet is its own terminal, the packet communication program performs polling packet reception processing (S23), polling response packet reception processing (S24), information notification packet reception processing (S25), inquiry according to the packet identification code 518 Packet reception processing (S26) is executed.

The packet communication program checks whether the ID of the network to which the terminal belongs and the network ID 511 of the packet match (S20). If the packet communication program determines that the ID of the network to which the terminal 10 belongs does not match the network ID set in the received packet (S20: NO), the process ends. This is because a packet outside the assigned range was received.

If the packet communication program determines that the ID of the network to which the terminal 10 belongs and the network ID of the received packet match (S20: YES), the packet communication program uses the destination node IP address 513 described in the common header 51 to It is determined whether the destination is its own terminal (S21).

When the packet communication program determines that the destination node that is the final delivery destination of the packet is not its own terminal (S21: NO), it refers to the next relay destination node IP address 516 set in the common header 51 of the packet. Then, the packet is transferred to the next terminal described therein (S27).

When the packet communication program determines that the destination of the received packet is its own terminal (S21: YES), it checks the packet identification code 518 of the packet (S22).

When the packet identification code is “00”, the packet communication program executes a process of receiving a polling packet (S23). When the packet identification code is “01”, the packet communication program receives a polling response packet (S24). Execute. When the packet identification code is “10”, the packet communication program executes a process of receiving an information notification packet (S25), and when the packet identification code is “11”, the packet communication program receives a query packet (S26). Execute. Details will be described later with reference to FIGS. 12, 13, 14, and 15, respectively.

FIG. 12 is a flowchart showing details of the polling packet reception process (S23) described in FIG. The polling packet reception processing S23 is one of the subroutines of the packet communication program as described in FIG. 11, and transmits the information notification packet 54 in accordance with the information notification packet transmission code 522 in the packet. Further, the polling packet reception process S23 transmits an inquiry packet 55 according to the inquiry flag 523 of the packet, and sets the data measured by the own terminal (periodically collected value) and the data detected by the adjacent terminal in the polling response packet 53. Then, the data is transmitted to the server 30.

The packet communication program confirms the value of the information notification packet transmission code 522 of the received polling packet 52 (S230). If the transmission code 522 is “00”, the packet communication program does nothing and moves to S233 described later. If the transmission code 522 is “10”, the packet communication program broadcasts the information notification packet 54 to surrounding terminals (S232). ", The information notification priority storage flag 542 is set (S231), and then the information notification packet 54 is broadcast (S232).

The packet communication program determines whether the inquiry flag 523 of the received polling packet 52 is set (S233). When the inquiry flag 523 is set (S233: TRUE), the packet communication program transmits an inquiry packet 55 to the terminal having the inquiry node IP address 524 (S234).

In the case where a timeout occurs after the inquiry packet 55 is transmitted or when the information notification packet 54 is received (S235), the packet communication program compares the adjacent terminal database 124 with the previous polling packet reception time. It is determined whether it has been updated (S236). The packet communication program can determine whether the adjacent terminal database 124 has been updated based on the reception strength of the information notification packet 54 received from another terminal (adjacent terminal) around the terminal.

If the packet communication program determines that the adjacent terminal database 124 has been updated (S236: YES), it stores data related to the adjacent terminal in the adjacent terminal database 124 (S237), and sends a polling response packet 53 to the data collection server 30. Transmit (S238).

When transmitting the polling response packet 53 in step S238, the routing information for transmitting the polling response packet 53 can be obtained by setting the routing information 515 to 517 of the received polling packet 52 in reverse order. Accordingly, the polling response packet 53 can be transmitted to the data collection server 30 by tracing back the route through which the polling packet 52 is relayed (S238).

If the inquiry flag 523 is determined not to be set (S233: FALSE), the packet communication program skips steps S234 and S235 and proceeds to step S236. If it is determined that the adjacent terminal database 124 is not updated (S236: NO), the packet communication program skips step S237 and proceeds to step S238.

FIG. 13 is a flowchart showing details of the polling response packet reception process (S24) described in FIG. The polling response packet reception process S24 is one of the subroutines of the packet communication program, and updates the periodic collection value database 331 and the link database 332 according to the data of the polling response packet 53 returned from the polling target terminal 10.

The packet communication program updates the regularly collected value database 331 based on the polling response data 534 of the received polling response packet 53 (S240). The packet communication program checks the adjacent terminal data code 535 of the polling response packet 53 and determines whether there is adjacent terminal data 537 (S241). If it is determined that there is adjacent terminal data 537 (S241: YES), the packet communication program updates the periodic collection value database 331 and the link database 332 with the adjacent terminal data 537 (S242).

In step S242, the packet communication program stores the data such as the periodic collection value of the adjacent terminal in the periodic collection value database 331, and further stores the data of the reception quality when the packet from the adjacent terminal is received in the link database 332. save.

FIG. 14 is a flowchart showing details of the information notification packet reception process S25 described in FIG. The information notification packet reception process S25 is one of subroutines of the packet communication program. In the information notification packet reception process S25, when the terminal 10 receives the information notification packet 54 transmitted from the adjacent terminal, the information notification data 545 is stored according to the priority.

The packet communication program checks whether the information notification priority storage flag 542 of the information notification packet 54 is set (S250). When it is determined that the save flag 542 is set (S250: TRUE), the packet communication program saves the information notification data 545 in the adjacent terminal databases 223 and 124 (S252).

When the packet communication program determines that the information notification priority saving flag 542 of the information notification packet 54 is not set (S250: FALSE), it determines whether to save the information notification (S251).

When it is determined that the packet communication program is to be saved, the information notification data 545 is saved in the adjacent terminal databases 223 and 124 (S252). If it is determined that the packet communication program is not to be saved, that is, if it is determined that the information notification data 545 is to be discarded, this processing ends.

Here, as a determination method in step S251, for example, whether or not to save is determined randomly based on a random number. When the power value at the time of reception of the information notification packet 54 is equal to or larger than a predetermined value, the information is stored and received. If the power value at the time is less than a predetermined value, it can be discarded, the gateway 20 does not store it, and the terminal 10 stores it as long as the memory is free.

If terminal 10 has a sufficient storage area, S250 and S251 may be removed, and information notification data 545 of all information notification packets 54 received by terminal 10 may be stored in adjacent terminal databases 223 and 124. .

FIG. 15 is a flowchart showing details of the inquiry packet reception process S26 described in FIG. The inquiry packet reception process S26 is one of the subroutines of the packet communication program. In the inquiry packet reception process S26, when the terminal 10 receives the inquiry packet 55 transmitted from the adjacent terminal, the information notification packet 54 in which the information notification priority storage flag 542 is set is broadcast.

The packet communication program sets the information notification priority storage flag 542 in the information notification packet 54 (S260). The packet communication program broadcasts the information notification packet 54 in which the information notification priority storage flag 542 is set (S261).

FIG. 16 is a sequence diagram illustrating an example of collecting data from each terminal 10 by polling using wireless multi-hop communication.

The periodic collection program 321 of the data collection server 30 determines the polling target to be the terminal 10 of the node ID 11 (S30), sets the information notification packet transmission code 522 to “10” (S31), and transmits the polling packet 52. (S32).

The packet communication program 221 of the gateway 20 transfers the polling packet 52 to the next relay destination node described in the routing information (S33).

When receiving the polling packet 52, the packet communication program 122 of the terminal 10 (ID11) determines the value of the information notification packet transmission code 522 (S34). Here, since “10” is set in the information notification packet transmission code in step S31, the packet communication program 122 broadcasts the information notification packet 54 in which the storage flag is not set (S35).

The terminal 10 (ID12) is an adjacent terminal that can directly perform wireless communication with the terminal 10 (ID11). When receiving the information notification packet 54 broadcast from the terminal 10 (ID11), the packet communication program 122 of the terminal 10 (ID12) determines whether or not to save the data of the packet 54 (S36). If it is determined that the packet communication program 122 of the terminal 10 (ID12) is to be saved, the information notification data 545 of the packet 54 received from the terminal 10 (ID11) is saved in the adjacent terminal database 124 of the terminal 10 (ID12) (S37). ). When the packet communication program 122 determines not to save, the packet communication program 122 discards the information notification packet 54 received from the terminal 10 (ID11).

On the other hand, when receiving the information notification packet 54 broadcast from the terminal 10 (ID11), the packet communication program 221 of the gateway 20 (ID1) determines whether or not to save the data of the packet 54 (S38). Here, it is assumed that the packet communication program 221 of the gateway 20 determines not to store the information notification data 545 of the information notification packet 54 and discards the packet 54.

The packet communication program 122 of the terminal 10 (ID11) confirms the data in the adjacent terminal database 124 possessed by the terminal 10 (ID11) (S39). If the packet communication program 122 of the terminal 10 (ID11) determines that there is no change in data compared to the previous transmission of the polling response packet 53, the packet communication program 122 transmits the normal polling response packet 53 to the server 30 (S40). .

The packet communication program 221 of the gateway 20 transfers the polling response packet 53 received from the terminal 10 (ID11) to the data collection server 30 as the next relay destination node (S41).

When receiving the polling response packet 53, the packet communication program 322 of the data collection server 30 stores the polling response data 534 in the periodic collection value database 331 (S42). When the packet communication program 322 confirms the adjacent terminal data code 535 (S43) and determines that the received polling response packet 53 does not include the data of the adjacent terminal, the packet communication program 322 ends.

By repeating the above operation, the data collection server 30 can update information (link information) about the adjacent terminals of the terminal 10 while collecting the regularly collected values from each terminal 10 in order.

FIG. 17 is a sequence diagram illustrating an example of acquiring the regularly collected value at the failed terminal via the adjacent terminal when polling the adjacent terminal of the terminal that has failed in the polling. Here, a case where polling to the terminal 10 (ID12) has failed will be described.

The periodic collection program 321 of the data collection server 30 sets the inquiry flag 523 for the terminal 10 (ID12) in the polling packet 52 to the terminal 10 (ID11) (S50), and sets the information notification packet transmission code 522 to “00”. (S51). The periodic collection program 321 transmits the polling packet 52 thus generated to the polling target terminal 10 (ID11) (S52).

The packet communication program 221 of the gateway 20 transmits the polling packet 52 to the terminal 10 (ID11) as the next relay destination node (S53).

When receiving the polling packet 52, the packet communication program 122 of the terminal 10 (ID11) determines the information notification packet transmission code 522 (S54). Here, since “00” is set in the information notification packet transmission code 522, the packet communication program 122 does not broadcast the information notification packet 54. That is, when an adjacent terminal (inquiry source terminal) that makes an inquiry to a failed terminal (failure-occurring terminal) receives a polling packet 52 addressed to itself, it does not broadcast the information notification packet 54 about the terminal. On the other hand, the information notification packet 54 may be broadcast from the inquiry source terminal.

The terminal 10 (ID11) confirms the inquiry flag 523, and transmits the inquiry packet 55 to the terminal 10 (ID12) that failed to poll (S56).

When the packet communication program 122 of the terminal 10 (ID12) receives the inquiry packet 55 from the adjacent terminal 10 (ID11) that is the inquiry source, the packet communication program 122 generates the information notification packet 54 in which the information notification priority storage flag 542 is set (S57), The information notification packet 54 is broadcast (S58).

When the packet communication program 122 of the terminal 10 (ID11) receives the information notification packet 54 broadcast from the failed terminal 10 (ID12), the information notification data 545 of the packet 54 is stored in the adjacent terminal database held by the terminal 10 (ID11). It is stored in 124 (S59). This is because the information notification priority saving flag 542 is set in step S57 in the information notification packet 54 received by the terminal 10 (ID11).

The packet communication program 122 of the terminal 10 (ID11) sets the data extracted from the information notification packet 54 of the terminal 10 (ID12) in the adjacent terminal data 537 of the polling response packet 53 (S60). The packet communication program 122 of the terminal 10 (ID11) transmits the polling response packet 53 having the adjacent terminal data to the data collection server 30 (S61).

The packet communication program 221 of the gateway 20 transmits the polling response packet 53 to the data collection server 30 which is the next relay destination node (S62). In FIG. 17, step S63 is shown as if executed backward, but in actuality, steps S63 to S66 are executed after steps S61 and S62.

When the packet communication program 322 of the data collection server 30 receives the polling response packet 53, it stores the periodic collection value of the terminal 10 (ID11) included in the polling response data 534 in the periodic collection value database 331 (S63).

The packet communication program 322 confirms the adjacent terminal data code 535 (S64), stores data such as a regularly collected value in the adjacent terminal data 537 in the regularly collected value database 331 (S65), and further receives reception quality data. Are stored in the link database 332 (S66).

As described above, even when polling to the terminal 10 fails due to a failure in the communication path, it is possible to give an opportunity for the terminal that has failed to transmit the information notification packet 54 by making an inquiry from the terminal 10 that is an adjacent terminal. . The data collection server 30 can collect the regularly collected values detected by the terminals that have failed polling via the neighboring terminal that is the inquiry source. As a result, the wireless data collection system 1 according to the present embodiment can quickly cope with a communication failure and has high usability.

Further, in this embodiment, when the inquiry from the adjacent terminal to the failed terminal succeeds, by setting a new communication path via the adjacent terminal, the new communication path is used in the next collection cycle. You can poll failed terminals. Therefore, according to the present embodiment, data of failed terminals can be collected and a new communication path can be set without depending on the number of pops to terminals that have failed polling. That is, in this embodiment, it is possible to recover from a failure regardless of the number of pops, and therefore it is easy to make a recovery plan outlook. Therefore, the wireless data collection system 1 of this embodiment has high fault tolerance and is easy to use.

In addition, this invention is not limited to the Example mentioned above. A person skilled in the art can make various additions and changes within the scope of the present invention.

10: Wireless sensor terminal, 20: Gateway, 30: Data collection server

Claims (10)

1. A wireless data collection system comprising a plurality of wireless sensor terminals and a server that acquires data from the plurality of wireless sensor terminals,
   The plurality of wireless sensor terminals are:
   Upon receiving a polling packet from the server, broadcast predetermined terminal information about the terminal to wireless sensor terminals around the terminal,
   Receives and holds predetermined terminal information related to the other wireless sensor terminals broadcast from other wireless sensor terminals around the terminal,
   Transmitting the predetermined terminal information regarding the own terminal and the predetermined terminal information regarding the other wireless sensor terminal to the server as a polling response to the polling packet;
   Wireless data collection system.
   
2. The predetermined terminal information related to the own terminal includes data detected by the own terminal,
   The predetermined terminal information related to the other wireless sensor terminal includes data detected by the other wireless sensor terminal.
   The wireless data collection system according to claim 1.
   
3. When the plurality of wireless sensor terminals hold the predetermined terminal information related to the other wireless sensor terminals, the wireless sensor terminals also hold information related to the state of wireless communication between the own terminal and the other wireless sensor terminals. And
   The polling response includes information related to the state of the wireless communication.
   The wireless data collection system according to claim 2.
   
4. Of the plurality of wireless sensor terminals, a faulty terminal that cannot respond to a polling packet from the server is located around the faulty terminal among the plurality of wireless sensor terminals and is capable of wireless communication with the faulty terminal. When a terminal receives a polling packet from the server, a predetermined inquiry is made from the peripheral terminal to the faulty terminal,
   When the failure occurrence terminal receives the inquiry from the peripheral terminal, it broadcasts the predetermined terminal information about the own terminal to wireless sensor terminals around the own terminal,
   The wireless data collection system according to claim 3.
   
5. The predetermined terminal information includes storage control information for controlling whether or not to store the predetermined terminal information.
   The wireless data collection system according to claim 4.
   
6. The polling packet issued by the server includes broadcast control information for controlling whether or not to permit broadcasting of the predetermined terminal information.
   The wireless data collection system according to claim 5.
   
7. When the predetermined inquiry is made from the peripheral terminal to the faulty terminal, the broadcast control information is set so as not to broadcast the predetermined terminal information from the peripheral terminal.
   The wireless data collection system according to claim 6.
   
8. The server includes a microprocessor, a memory for storing a predetermined server-side computer program executed by the microprocessor, and a communication unit for communicating with the plurality of wireless sensor terminals using a wireless multi-hop network. And
   By executing the predetermined server-side computer program by the microprocessor,
   Select a polling target terminal to be polled this time from the plurality of wireless sensor terminals,
   Determine whether the selected polling target terminal is a peripheral terminal capable of wireless communication with a faulty terminal that could not acquire data during the previous polling process,
   When it is determined that the polling target terminal is the peripheral terminal, a polling packet including inquiry information for requesting an inquiry to the faulty terminal is transmitted to the polling target terminal,
   When a polling response is received from the polling target terminal, from the predetermined terminal information included in the polling response, data detected by the polling target terminal and other wireless sensors located around the polling target terminal Retrieve information indicating a wireless communication state based on a reception state of predetermined terminal information broadcast from the terminal and data detected by the other wireless sensor terminal, update a predetermined database,
   The plurality of wireless sensor terminals use a microprocessor, a memory for storing a predetermined terminal-side computer program executed by the microprocessor, a sensor unit for detecting data, the server, and a wireless multi-hop network. A communication unit for communicating
   By executing the predetermined terminal-side computer program by the microprocessor,
   Receiving the polling packet from the server;
   Determine whether the inquiry information is included in the received polling packet,
   When it is determined that the inquiry information is included in the polling packet, a predetermined inquiry is performed to the failure occurrence terminal,
   Receiving predetermined terminal information from the faulty terminal responding to the inquiry;
   Transmitting the predetermined terminal information about the own terminal and the predetermined terminal information about the faulty terminal to the server as a polling response to the polling packet;
   The wireless data collection system according to claim 1.
   
9. A method of collecting data from each of the wireless sensor terminals using a plurality of wireless sensor terminals and a server that acquires data from the plurality of wireless sensor terminals,
   The plurality of wireless sensor terminals are:
   Upon receiving a polling packet from the server, broadcast predetermined terminal information about the terminal to wireless sensor terminals around the terminal,
   Receives and holds predetermined terminal information related to the other wireless sensor terminals broadcast from other wireless sensor terminals around the terminal,
   Transmitting the predetermined terminal information regarding the own terminal and the predetermined terminal information regarding the other wireless sensor terminal to the server as a polling response to the polling packet;
   Wireless data collection method.
   
10. A server used for a wireless data collection system comprising a plurality of wireless sensor terminals and a server for acquiring data from the plurality of wireless sensor terminals,
    Select a polling target terminal to be polled this time from the plurality of wireless sensor terminals,
    Determine whether the selected polling target terminal is a peripheral terminal capable of wireless communication with a faulty terminal that could not acquire data during the previous polling process,
    When it is determined that the polling target terminal is the peripheral terminal, a polling packet including inquiry information for requesting an inquiry to the faulty terminal is transmitted to the polling target terminal,
    When a polling response is received from the polling target terminal, from the predetermined terminal information included in the polling response, data detected by the polling target terminal and other wireless sensors located around the polling target terminal Extracting information indicating a wireless communication state based on a reception state of predetermined terminal information broadcast from the terminal and data detected by the other wireless sensor terminal, and updating a predetermined database;
    Server for wireless data collection system.

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