JP7074941B1 - Topology estimation system and topology estimation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately estimate a topology of a sensor network. SOLUTION: The topology estimation system of the present invention has a sensor node associated with each of a plurality of meters, a repeater connected to the sensor node and collecting meter information through the sensor node, and a sensor node and a repeater. , A center control unit that collects meter information by a multi-hop type sensor network and a topology control unit that estimates the topology of the sensor network, and the topology control unit satisfies the first communication distance condition N + 1 ( N ≧ 0) It is determined that the sensor node with the number of hops and the sensor node with the number of N hops are connected (S14), and the sensor nodes having the same number of hops and satisfying the second communication distance condition are connected to each other. It is determined that there is (S26). [Selection diagram] FIG. 6

Description

The present invention relates to a sensor network topology estimation system and a topology estimation method.

Gas companies and electric power companies place gas meters and electric power meters at demand points in order to integrate the amount of gas and electric power used by consumers. In recent years, the installation of smart meters that have a communication function, perform bidirectional data communication with gas companies and electric power companies, and can automatically remotely read the amount of gas and electric power used has been promoted. ing. Such smart meters can also be used as an information source for improving the safety and utilization efficiency of infrastructure networks such as gas and electric power.

In addition, various means have been proposed to realize data communication between the above-mentioned smart meter and a gas company or an electric power company. For example, a short-range wireless device may be installed in a smart meter to form a mesh-type network, a star-type network may be formed by a mobile phone network such as LTE (Long Term Evolution), or a star-type network may be created by power line communication. It is possible to form.

Further, Patent Document 1 discloses a sensor network system in which sensor information for each sensor node communication terminal is stored in a data server and the stored sensor information is analyzed by a data management unit. The data management unit can perform self-diagnosis of the sensor node communication terminal according to the failure diagnosis algorithm, and can perform maintenance of the sensor node communication terminal determined to be a failure.

Japanese Unexamined Patent Publication No. 2016-103187

For example, there is a sensor network in which a sensor node is associated with each meter that measures gas usage and the like, and meter information is collected in a center device through the sensor node and a repeater. In this sensor network, sensor nodes and the like are newly installed in accordance with the replacement of the meter, so that the sensor network is expanded or changed over time. Therefore, in this sensor network, the installation status and communication environment of each device may change with the passage of time. In order to properly perform failure diagnosis and maintenance of meters and sensor nodes in such a changing sensor network, it is necessary to properly estimate the topology of the sensor network.

An object of the present invention is to provide a topology estimation system capable of appropriately estimating the topology of a sensor network, and a topology estimation method.

In order to solve the above problems, the topology estimation system of the present invention has a sensor node associated with each of a plurality of meters, a repeater connected to the sensor node and collecting meter information through the sensor node, and a sensor node. A center control unit that collects meter information by a multi-hop type sensor network and a topology control unit that estimates the topology of the sensor network are provided, and the topology control unit satisfies the first communication distance condition. It is determined that the sensor node with the number of N + 1 (N ≧ 0) hops and the sensor node with the number of N hops are connected, and the sensor nodes having the same number of hops and satisfying the second communication distance condition are connected to each other. It is determined that it is.

The topology control unit determines that a sensor node with an N hop number whose connection date connected to the sensor network is later than the connection date of the sensor node with an N + 1 hop number is connected to the sensor node with an N + 1 hop number. It may be excluded.

When there is no sensor node with N + 1 hops and a sensor node with N hops that satisfies the first communication distance condition, the topology control unit determines the connection date connected to the sensor network from the connection date of the sensor node with N + 1 hops. It is determined that the sensor node with N + 1 hops, the sensor node with the shortest relative distance, and the sensor node with N + 1 hops are connected among the sensor nodes with N hops that are one of the previous days. You may do so.

The topology control unit does not have a sensor node with N + 1 hops and a sensor node with N hops that satisfies the first communication distance condition, and the connection date connected to the sensor network is from the connection date of the sensor node with N + 1 hops. If there is no sensor node with N hops that is one of the previous days, the sensor node with N + 1 hops, the sensor node with the shortest relative distance, and the sensor node with N + 1 hops are connected. It may be determined that.

The topology control unit may determine that the node having the number of N + M hops (M ≧ 2) and the node having the number of N hops are not connected.

In order to solve the above problems, a sensor node associated with each of a plurality of meters, a repeater connected to the sensor node and collecting meter information through the sensor node, and a multi-hop format through the sensor node and the repeater. The topology estimation method of the present invention, which estimates the topology of a sensor network having a center control unit that collects meter information by the sensor network of the above, has N + 1 (N ≧ 0) hops that satisfy the first communication distance condition. A topology estimation method in which it is determined that the sensor node and the sensor node having N hops are connected, and the sensor nodes having the same number of hops and satisfying the second communication distance condition are connected to each other.

According to the present invention, it is possible to appropriately estimate the topology of the sensor network.

It is explanatory drawing which showed the schematic structure of the sensor network to which a maintenance system is applied. It is a functional block diagram which showed the schematic structure of a center device. It is explanatory drawing for demonstrating the structure of a meter database. It is a functional block diagram which showed the schematic structure of the topology estimation apparatus. It is explanatory drawing for demonstrating the processing of a topology estimation part. It is a flowchart which showed the flow of the topology estimation method which concerns on 1st Embodiment. It is explanatory drawing for demonstrating other processing of a topology estimation part. It is explanatory drawing for demonstrating other processing of a topology estimation part. It is a functional block diagram which showed the schematic structure of the maintenance device. It is a flowchart explaining the operation flow of the maintenance control unit which concerns on 2nd Embodiment. It is a flowchart explaining the operation flow of the maintenance control unit which concerns on 2nd Embodiment. It is a flowchart explaining the operation flow of the maintenance control unit which concerns on 2nd Embodiment. It is a flowchart explaining the operation flow of the maintenance control unit which concerns on 2nd Embodiment. It is a flowchart explaining the operation flow of the maintenance control unit which concerns on 2nd Embodiment. It is a flowchart explaining the operation flow of the maintenance control unit which concerns on 2nd Embodiment. It is a flowchart explaining the operation flow of the maintenance control unit which concerns on 2nd Embodiment. It is a flowchart explaining the operation flow of the maintenance control unit which concerns on 3rd Embodiment. It is a flowchart explaining the operation flow of the maintenance control unit which concerns on 3rd Embodiment. It is a flowchart explaining the operation flow of the maintenance control unit which concerns on 3rd Embodiment. It is a flowchart explaining the operation flow of the maintenance control unit which concerns on 3rd Embodiment. It is a flowchart explaining the operation flow of the maintenance control unit which concerns on 3rd Embodiment. It is a flowchart explaining the operation flow of the maintenance control unit which concerns on 3rd Embodiment. It is a flowchart which showed the flow of the Lowlink method. It is explanatory drawing for demonstrating the processing of maintenance control part. It is explanatory drawing for demonstrating other processing of maintenance control part. It is explanatory drawing for demonstrating the image of grouping. It is explanatory drawing for demonstrating maintenance in a group. It is explanatory drawing for demonstrating maintenance between groups. It is explanatory drawing for demonstrating maintenance between groups.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, other specific numerical values, etc. shown in the embodiment are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and the drawings, elements having substantially the same function and configuration are designated by the same reference numerals to omit duplicate description, and elements not directly related to the present invention are not shown. do.

(Sensor network 100)
FIG. 1 is an explanatory diagram showing a schematic configuration of a sensor network 100 to which the maintenance system 1 is applied. As shown in FIG. 1, the sensor network 100 includes a plurality of meters 110, a plurality of sensor nodes 112, a plurality of repeaters 114, a center device 116, and a base station 118.

The meter 110 is, for example, a smart meter, and is installed for each dwelling unit of a consumer, that is, an individual house or an apartment house. The meter 110 is a device that automatically reads at least the amount of gas or electric power used when the gas operator supplies gas to the consumer or the electric power operator supplies electric power to the consumer. In this embodiment, for convenience of explanation, the gas meter 110 by a gas company is illustrated, but it goes without saying that it can also be applied to electric power (electricity).

The sensor nodes 112 are installed in a one-to-one correspondence with each of the meters 110, and at least transmit and receive information (data) used by the meters 110.

The repeater 114 functions as a gateway device for connecting different networks, and is installed in association with any of the plurality of sensor nodes 112. The repeater 114 establishes wire communication with the sensor node 112 associated with the repeater 114, and also establishes communication with the center device 116. Then, the repeater 114 establishes wireless communication with one or a plurality of surrounding sensor nodes 112 through the associated sensor node 112.

However, since communication between the sensor nodes 112 is realized by short-range radio, not all sensor nodes 112 can directly establish wireless communication with the sensor node 112 associated with the repeater 114. .. In this case, the sensor node 112 is connected to the repeater 114 by hopping (via) another sensor node 112 capable of wireless communication one or more times. In this way, the repeater 114 transmits the information of each sensor node 112 to the center device 116 and the information of the center device 116 to the surrounding sensor node 112 through the associated sensor node 112 and other sensor nodes 112 around it. Can be sent to. That is, the repeater 114 communicates with the sensor node 112 in a multi-hop format to collect information on the meter 110, and the center device 116 establishes communication with the repeater 114 and receives the information on the meter 110. At this time, since the transmitted information includes an identifier that identifies the repeater 114 and the base station 118 that were passed through when the information was transmitted, the center device 116 determines the source and route of the information. Can be identified.

The center device 116 is a device composed of a computer or the like and belongs to the administrator side of the sensor network 100 such as a gas company or an electric power company. The center device 116 establishes communication with one or more repeaters 114 to collect or transmit information. The position (coordinate information) where the meter 110 is installed is managed by the center device 116 through conduit mapping (GIS system). Therefore, the position of the sensor node 112 installed on the meter 110 and the position of the repeater 114 attached to the sensor node 112 can also be specified by the conduit mapping.

The base station 118 can establish communication with both the repeater 114 and the center device 116, and relays the communication between the repeater 114 and the center device 116.

By constructing the sensor network 100 as described above, it becomes possible to collect meter reading information (automatic meter reading) without the meter reading staff of the gas company directly reading the meter 110, thereby improving work efficiency. be able to.

Here, communication between each device will be described. For example, the wireless communication between the repeater 114 and the base station 118, and the communication between the base station 118 and the center device 116 are used for the communication volume of a mobile phone network, a PHS (Personal Handyphone System) network, for example, LTE. An existing pay communication network that incurs communication charges will be used accordingly. Such a pay communication network is managed by, for example, a communication company, which is different from a gas company or an electric power company.

The sensor nodes 112 establish wireless communication with each other, for example, through a wireless system for smart meters (U-Bus Air) using the 920 MHz band. It is assumed that the wireless communication between the sensor nodes 112 is free of charge, but the communication cost may be at least lower than the communication between the repeater 114 and the center device 116 regardless of whether the sensor nodes are charged or free of charge. Through such wireless communication, the repeater 114 is connected to the center device 116 through the pay communication network and is connected to each sensor node 112 through the smart meter wireless system.

In the sensor network 100, the meter 110 and the sensor node 112 are arranged for each consumer. Further, as described above, the repeater 114 may be provided side by side with the meter 110 and the sensor node 112. The center device 116 collects information on the meter 110 or controls the meter 110 through the sensor node 112 and the repeater 114. Therefore, the sensor node 112 and the repeater 114 will be arranged at any position where the consumer exists.

Here, the communication between the sensor node 112 and the center device 116 is performed by using the wireless system for the smart meter from the sensor node 112 to the repeater 114 and the existing pay communication network from the repeater 114 to the center device 116 together. Is realized at low cost. That is, the repeater 114 collects information from the plurality of sensor nodes 112 through ad hoc communication that does not require a separate communication fee. Then, the repeater 114 transmits the collected information to the center device 116 at a time, for example, once a day for a short time, although the communication fee is consumed. In this way, the use of the pay communication network of the repeater 114 can be minimized, and the communication cost of the entire sensor network 100 can be reduced.

Further, since the wireless system for smart meters assumes short-range wireless communication, the power consumed for wireless communication is relatively small. Therefore, the power source of the sensor node 112 can be supplied by a battery or the like, and the power consumption of the sensor network 100 can be reduced. Since the pay communication network consumes power relatively easily as compared with the wireless system for smart meters, it requires a large capacity battery or a separate power source. However, since the absolute number of repeaters 114 is smaller than that of the sensor node 112, and the communication frequency and communication time per unit are small, it is consumed as compared with the case where the mobile phone network is always used from all the sensor nodes 112. Power can be kept extremely low.

Further, in the sensor network 100, an allowable value indicating an allowable maximum value of the number of sensor nodes 112 (in other words, the number of meters 110) that can be assigned to one repeater 114 is predetermined. The permissible value is, for example, 47, but can be arbitrarily set according to the specifications of the sensor node 112 to which the repeater 114 is attached. The sensor node 112 to which the repeater 114 is attached knows the number of sensor nodes 112 assigned to the repeater 114 and the allowable value. The repeater 114 establishes communication with the meter 110 corresponding to the assigned sensor node 112.

Further, of the communication paths between the meter 110 and the center device 116, the one relatively close to the center device 116 may be referred to as an upstream, and the one relatively far from the center device 116 may be referred to as a downstream. Further, the sensor node 112 assigned to one repeater 114, and the sensor node 112 downstream of the repeater 114 may be referred to as a subordinate of the repeater 114. The repeater 114 and the sensor node 112 under the repeater 114 are managed with the same identifier (network ID described later).

FIG. 2 is a functional block diagram showing a schematic configuration of the center device 116. The center device 116 includes a center communication unit 122, a center holding unit 124, and a center control unit 126.

The center communication unit 122 establishes communication with the repeater 114 through the base station 118. The center holding unit 124 is composed of a RAM, a flash memory, an HDD, and the like, and holds various information such as a conduit mapping used for the center device 116 and a meter database described later. The center control unit 126 includes a processor and a memory for storing a program. The center control unit 126 manages the entire sensor network 100 by executing a program by the processor. The center control unit 126 acquires information on each meter 110 through each repeater 114, for example, at a predetermined time every day. Further, the center holding unit 124 stores a meter database including various information about each meter 110.

FIG. 3 is an explanatory diagram for explaining the configuration of the meter database. In the meter database, the meter ID, network ID, repeater ID, sensor node ID one hop upstream of the meter 110, communication success rate, number of hops, etc. are associated with all the meters 110 used in the sensor network 100. Has been done.

The meter ID is an identifier that uniquely identifies the meter 110. The network ID is an identifier that uniquely identifies one repeater 114 and a group of sensor nodes 112 under the repeater 114. Each meter 110 to which a common repeater 114 is assigned is assigned the same network ID. The repeater ID is an identifier that uniquely identifies the repeater 114 to which the sensor node 112 associated with the meter 110 actually establishes communication. The sensor node ID one hop upstream is an identifier that uniquely identifies the sensor node 112 one hop upstream from the sensor node 112 corresponding to the meter 110. The communication success rate is the ratio of the number of successful communications to the number of communication attempts between the meter 110 and the center device 116. The number of hops is the number of hops from the sensor node 112 corresponding to the meter 110 to the sensor node 112 to which the repeater 114 is attached.

The meter database is not limited to the illustrated information, and may include arbitrary information regarding the meter 110. For example, in the meter database, repeater attachment information indicating whether or not the repeater 114 is attached to the sensor node 112 corresponding to the meter 110 may be associated with the meter ID. Further, the meter database may be associated with load survey information indicating the result of success or failure of the daily load survey, which is associated with the meter ID. Further, in the meter database, the day when the meter 110 is installed, the day when the sensor node 112 corresponding to the meter 110 is installed (construction date), and the sensor node 112 corresponding to the meter 110 are added to the sensor network 100. Construction information showing the history of various works such as the date of connection (connection date), the date when the repeater 114 was attached to the meter 110, and the date when the repeater 114 was removed from the meter 110 is associated with the meter ID. May be.

(Topology estimation system according to the first embodiment)
By the way, in the sensor network 100, the verification validity period is fixed, for example, 10 years, and with the expiration of the verification validity period, the meter 110 is replaced in order to prevent problems due to aging deterioration. Further, the sensor node 112 and the repeater 114 may be replaced with the replacement of the meter 110. After that, the expiration of the valid period of the test may be referred to as the test.

For example, the meter 110 may be replaced by the inspection of the meter 110 to which the sensor node 112 is not attached, and the sensor node 112 may be newly attached to the replaced meter 110. When the number of sensor nodes 112 increases in this way, the number of repeaters 114 for the sensor nodes 112 may be insufficient in some cases. If the number of repeaters 114 is insufficient, it is necessary to newly install (in other words, retrofit) the repeaters 114. Further, when the building in which the meter 110 is installed is demolished, the meter 110, the sensor node 112, or the repeater 114 may also be removed. Further, it may be difficult to succeed in establishing communication between the sensor nodes 112 due to the construction of a new building around the sensor node 112. As described above, in the sensor network 100, the installation status of each device, the communication environment, and the like may change with the passage of time.

In order to perform failure diagnosis and maintenance of the meter 110 and the sensor node 112 in the sensor network 100 with such changes, the topology (connection relationship) of the sensor network must first be estimated. Here, it is an object to appropriately estimate the topology of the sensor network 100.

The sensor network 100 employs a multi-hop format, and it is not necessary to grasp the topology in advance in order to establish communication between the repeater 114 and each sensor node 112. Therefore, the topology is not generated in the existing sensor network 100.

As shown in FIG. 1, the topology estimation system of the sensor network 100 of this embodiment includes a topology estimation device 130. The topology estimation device 130 can establish communication with the center device 116, and can acquire necessary information from the center holding unit 124 of the center device 116. In the sensor network 100, as described above, the topology is not grasped, but the number of hops of the sensor node 110 is grasped because the communication between the repeater 114 and each sensor node 112 is established. Therefore, the topology estimation device 130 estimates the topology of the sensor network 100 based on the number of hops during operation of the sensor network 100.

FIG. 4 is a functional block diagram showing a schematic configuration of the topology estimation device 130. The topology estimation device 130 includes a topology communication unit 132, a topology holding unit 134, and a topology control unit 136.

The topology communication unit 132 establishes communication with the center device 116 by wired communication or wireless communication. The topology holding unit 134 is composed of a RAM, a flash memory, an HDD, and the like. The topology holding unit 134 holds various information such as information included in the meter database and information on conduit mapping acquired from the center device 116 through the topology communication unit 132. The topology control unit 136 includes a processor and a memory for storing a program.

The topology control unit 136 acquires information necessary for estimating the topology from the center device 116 and stores it in the topology holding unit 134. The topology control unit 136 executes a program and estimates the topology of the sensor network 100 with reference to the information (for example, a meter database) stored in the topology holding unit 134.

FIG. 5 is an explanatory diagram for explaining the processing of the topology control unit 136. In the sensor network 100 shown in FIG. 5, the sensor node 112 is represented by a circle “◯”, and the number of hops is indicated by the numerical value in the circle. For example, since the sensor node 112 associated with the repeater 114 located at the upper left of FIG. 5A has 0 hops, “0” is added in the circle. Further, the other sensor nodes 112 are assigned numerical values of "1" to "4" according to the number of hops.

The topology control unit 136 refers to the meter database held in the topology holding unit 134, and has the same network ID, that is, the meter ID to which the common repeater 114 shown in FIG. 5 is assigned, and the number of hops thereof. Get the connection date.

The topology control unit 136 estimates the topology for the number of hops based on the following concept. For example, a sensor node 112 with N + 1 hops (an integer of N ≧ 0) should be connected to at least one sensor node 112 with an N hop number. This is based on the fact that the sensor node 112 having the number of N + 1 hops has the number of hops N + 1 because it is connected to the sensor node 112 having the number of N hops. Further, the sensor node 112 of N + M hops (integer of M ≧ 2) and the sensor node 112 of the number of N hops should not be directly connected (in one hop). Assuming that the sensor node 112 with N + M hops and the sensor node 112 with N hops are connected, the sensor node 112 with N + M hops becomes the sensor node 112 with N + 1 and the sensor node with N + M hops. It is based on not being 112.

FIG. 6 is a flowchart showing the flow of the topology estimation method. The topology control unit 136 executes a topology estimation method for estimating the topology of the sensor network 100 shown in FIG. 5A based on the above concept. Here, the topology of the sensor network 100 is estimated based on the connection date of the sensor node 112 in addition to the number of hops.

First, the topology control unit 136 extracts the sensor node 112 having an arbitrary number of N + 1 hops (S10). Next, the topology control unit 136 determines that the sensor node 112 having an arbitrary N + 1 hop number is connected based on the connection date connected to the sensor network 100, and the sensor node has a predetermined N hop number. 112 is temporarily excluded (S12). This is based on the following reasons. That is, in the next step S14, it is determined that the sensor node 112 having an N hop number whose relative distance is equal to or less than the first specified value and the sensor node 112 having an arbitrary N + 1 hop number are connected (in S16). YES), the connection determination process of the subsequent steps S18 to S22 will not be executed. Then, originally, the connection determination process itself of the sensor node 112 having the number of N hops, which should be determined to be highly likely to be connected to the sensor node 112 having the number of N + 1 hops, is not executed by the connection determination process of steps S18 to S22. It will be.

Therefore, here, the sensor node 112 having a predetermined N hop number is temporarily excluded from the target for determining that the sensor node 112 having an arbitrary N + 1 hop number is connected based on the connection date connected to the sensor network 100. do. Then, by the connection determination process in steps S18 to S22, the sensor node 112 having the number of N hops that should be determined to have a high possibility of being originally connected can be extracted. If the sensor node 112 having a predetermined number of N hops is excluded, the sensor node 112 having such an N hop number will not be the target of the connection determination process in step S14. Therefore, as will be described later, in step S24, the same connection determination process as in step S14 is performed again for the sensor node 112 having a predetermined number of N hops.

FIG. 7 is an explanatory diagram for explaining other processes of the topology control unit 136. Here, it is assumed that the connection date of the sensor node 112 is associated with the meter ID in the meter database. Here, the connection date indicates the timing at which the sensor node 112 is first connected to the sensor network 100, and is represented by a year, a month, and a day. The time may be included in the connection date.

Specifically, in step S12, the topology control unit 136 attaches the sensor node 112 having an N hop number whose connection date connected to the sensor network 100 is later than the connection date of the sensor node 112 having an N + 1 hop number to N + 1 hops. Exclude from the target to be determined that the sensor node 112 is connected.

In FIG. 7A, it is assumed that the connection dates of the sensor nodes 112 having one hop are 1/1, 3/1, and 4/1, respectively. Further, it is assumed that the connection date of the sensor node 112 having two hops is 3/1. Here, for convenience of explanation, it is represented by month / day, and the year and time are omitted, but it is assumed that they are all connected to the same year, and the time is arbitrary.

Here, on 3/1, which is the connection date when the sensor node 112 having 2 hops is connected, the sensor node 112 having 1 hop number, which has a connection date of 4/1, is not connected to the sensor network 100, so that the sensor node 112 is connected. The sensor node 112 having a number of 2 hops with a date of 3/1 is connected to the sensor network 100 in a state where the sensor node 112 having a number of 1 hop with a connection date of 4/1 does not exist. That is, at least on 3/1, the sensor node 112 having 2 hops with a connection date of 3/1 is connected to any of the sensor nodes 112 with 1 hop number before 3/1, regardless of their relative distances. It will be done.

Therefore, the topology control unit 136 has a connection date later than the sensor node 112 having two hops from the target for determining that the sensor node 112 having two hops shown by the solid line in FIG. 7B is connected. The sensor node 112 with one hop number connected to 4/1 can be temporarily excluded (indicated by “x” in FIG. 7 (b)). In this way, the topology control unit 136 has 2 hops with a connection date of 3/1 from the remaining sensor nodes 112 with 1 hop with a connection date before 3/1 (1/1, 3/1, etc.). It is possible to extract the sensor node 112 having one hop number in which the sensor node 112 of the above is likely to be connected.

Even if the connection date of the sensor node 112 having one hop is 4/1, which is later than 3/1, the connection date is 4/1 with the sensor node 112 having 2 hops, which is 3/1. If the relative distance to the sensor node 112 for one hop is equal to or less than the specified value, it is determined in step S24 described later that the two are connected, so that there is no problem.

Returning to FIG. 6, the topology control unit 136 derives the installation position (latitude, longitude, altitude) of the extracted sensor node 112 with the number of N + 1 hops by referring to the information of the conduit mapping. Further, the topology control unit 136 determines the relative distance between the extracted sensor node 112 having N + 1 hops and the sensor node 112 having all N hops on the sensor network 100 having the same network ID. Derived. Here, the relative distance refers to the linear distance between the two sensor nodes 112. Then, the topology control unit 136 communicates with the sensor node 112 having the extracted N + 1 hops and the first communication if the derived relative distance satisfies the first communication distance condition, that is, if the relative distance is equal to or less than the first specified value. It is determined that the sensor node 112 having the number of N hops satisfying the distance condition is connected (S14).

Here, the first specified value is a distance according to the type of dwelling units in which the meter 110 associated with the sensor node 112 is installed, that is, a predetermined distance at which it can be determined that communication is possible, for example. The distance between detached houses is 30 m, the distance between detached houses and rebar apartments is 20 m, and the distance between rebar apartments is 10 m. In this way, as shown by the solid line in FIG. 5B, for example, the sensor node 112 having the number of hops “0” and the sensor node 112 having the number of hops “1” are connected to the sensor node 112 having the number of hops “1”. The sensor node 112 with the number of hops "2" is connected, the sensor node 112 with the number of hops "2" and the sensor node 112 with the number of hops "3" are connected, and the sensor node 112 with the number of hops "3" and the number of hops "4" are connected. The sensor node 112 is connected.

Next, in step S14, the topology control unit 136 determines whether or not the extracted sensor node 112 having N + 1 hops is connected to the sensor node 112 having any N hops (S16). As a result, when there is no sensor node 112 having the number of N hops connected to the sensor node 112 having the number of N + 1 hops extracted (NO in S16), the topology control unit 136 has a connection date of N + 1 connected to the sensor network 100. It is determined whether or not there is a sensor node 112 having an N hop number, which is any one from the connection date of the sensor node 112 having the number of hops to a predetermined number of days (for example, 3 days) (S18). As a result, if there is a sensor node 112 having an N hop number whose connection date connected to the sensor network 100 is any one from the connection date of the sensor node 112 having an N + 1 hop number to a predetermined number of days before (in S18). YES), the topology control unit 136 has one or more N-hop sensor nodes whose connection date connected to the sensor network 100 is any one from the connection date of the N + 1 hop sensor node 112 to a predetermined number of days before. Of the 112, it is determined that the sensor node 112 having the number of N + 1 hops, the sensor node 112 having the shortest relative distance, and the sensor node 112 having the number of N + 1 hops are connected (S20).

FIG. 8 is an explanatory diagram for explaining other processes of the topology control unit 136. Here, for convenience of explanation, the construction date is also shown as a reference in addition to the connection date of the sensor node 112. Here, the construction date indicates the timing when the sensor node 112 is constructed on the sensor network 100, and is represented by a year, a month, and a day. The time may be included on the construction date. When the meter 110 and the sensor node 112 are constructed at the same timing, the year, month, and day when the meter 110 is arranged in the sensor network 100 may be adopted as the construction date.

In FIG. 8A, the connection dates of the sensor nodes 112 having one hop are 1/1, 3/1, 4/1, respectively, and the construction dates are 1/1, 3/1, 4/1, respectively. Suppose. Further, it is assumed that the connection date of the sensor node 112 having 2 hops is 3/1 and the construction date is 2/1. Here, for convenience of explanation, it is represented by month / day, and the year and time are omitted, but it is assumed that they are all connected and constructed in the same year, and the time is arbitrary.

Then, it is assumed that there is no sensor node 112 having one hop number whose relative distance to the sensor node 112 having two hops is equal to or less than the specified value. In this case, as described with reference to FIG. 7, the topology control unit 136 determines that the sensor node 112 having two hops is connected based on the connection date, and the sensor node 112 having two hops is connected. The sensor node with one hop number connected to 4/1 whose connection date is later is excluded. In this way, the topology control unit 136 has the sensor node 112 having 2 hops with a connection date of 3/1, the remaining sensor node 112 having 1 hop with a connection date of 1/1, and the connection date of 1/3. When connected to any of the sensor nodes 112 having the number of hops, the target can be limited.

Here, the sensor node 112 having two hops is constructed on 2/1. If the sensor node 112 with 2 hops with a construction date of 2/1 and the sensor node 112 with 1 hop with a connection date of 1/1 and a construction date of 1/1 are connected, the number of 2 hops is assumed. The connection date of the sensor node 112 of the above should be 2/1, which is the construction date of the sensor node 112 having 2 hops, or at least 2/1 to within a predetermined number of days. However, the connection date of the sensor node 112 having two hops is from 2/1, which is the construction date, to 3/1, which is later than the predetermined number of days. Therefore, the topology control unit 136 can exclude at least one sensor node 112 having a construction date of 1/1 from the target for determining that the sensor node 112 having two hops is connected.

On the other hand, 3/1, which is the connection date of the sensor node 112 having 1 hop number of construction dates, is equal to 3/1, which is the connection date of the sensor node 112 having 2 hops. That is, the connection date of the sensor node 112 having one hop number of construction date is 3/1, whichever is from 3/1, which is the connection date of the sensor node 112 having 2 hops, to a predetermined number of days (for example, 3 days) before. It has become. Therefore, in the topology control unit 136, the sensor node 112 having 2 hops with a connection date of 3/1 has the shortest relative distance among the sensor nodes 112 having 1 hop with a connection date of 3/1. It can be determined that the node 112 is connected. Here, "the shortest relative distance" is defined as the sensor node 112 having a connection date of 3/1 and a number of 2 hops when there are a plurality of sensor nodes 112 having a connection date of 3/1 and a number of 1 hops. This is because the sensor node 112 having the shortest relative distance and having one hop number is most likely to be connected to the sensor node 112 having two hops having a connection date of 3/1.

Here, the sensor node 112 having any N-hop number from the connection date of the sensor node 112 having N + 1 hops to a predetermined number of days (for example, 3 days) before the connection date connected to the sensor network 100 is used. An example of determining that the sensor node 112 having N + 1 hops is connected has been described. This is because the sensor node 112 independently establishes communication with the other sensor node 112, so that the sensor node 112 having N + 1 hops has the number of N hops based on the connection of the sensor node 112 having N hops. This is because even if they are connected to the sensor node 112 of the above, the connection dates are not always the same (same day). Therefore, here, if the range is from the connection date to a predetermined number of days before, for example, from 3 days before to the connection date, the sensor node 112 with N + 1 hops has N hops based on the connection of the sensor node 112 with N hops. It can be determined that the sensor node 112 is connected to the sensor node 112.

With such a configuration, it becomes possible to stably extract the sensor node 112 having the number of N hops that should be determined to have a high possibility of being originally connected.

Returning to FIG. 6, if the connection date connected to the sensor network 100 is any one from the connection date of the sensor node 112 having N + 1 hops to a predetermined number of days before, the sensor node 112 having N hops does not exist (S18). NO), the topology control unit 136 states that the extracted sensor node 112 having N + 1 hops is connected to the sensor node 112 having the shortest relative distance among the sensor nodes 112 having N hops. Judgment (S22).

Here, it is not possible to specify which N-hop number sensor node 112 is actually connected to the extracted N + 1 hop number sensor node 112, but as long as it is N + 1 hop number, at least the N-hop number sensor node It should be connected to 112. Therefore, it is assumed that the sensor node 112 having N + 1 hops is connected to the sensor node 112 having the shortest relative distance. In this way, as shown by the broken line in FIG. 5B, for example, the sensor node 112 having the number of hops “2” and the sensor node 112 having the number of hops “3” are connected.

Next, if the relative distance between the sensor node 112 having the number of N hops excluded in step S12 and the sensor node 112 having the number of extracted N + 1 hops is equal to or less than the first specified value, the topology control unit 136 has extracted N + 1. It is determined that the sensor node 112 having the number of hops and the sensor node 112 having the number of N hops satisfying the first communication distance condition are connected (S24). In this way, the same connection determination process as in step S14 can be executed for the sensor node 112 having the number of N hops excluded in step S12.

Subsequently, the topology control unit 136 is a relative distance between the extracted position information of the sensor node 112 having the number of N + 1 hops and the position information of the sensor nodes 112 having the same number of N + 1 hops on the sensor network 100 having the same network ID. Is derived. Then, if the relative distance satisfies the second communication distance condition, that is, the relative distance is equal to or less than the second specified value, the topology control unit 136 sets the extracted sensor node 112 having N + 1 hops and the second communication distance condition. It is determined that the sensor node 112 having the number of N + 1 hops to be satisfied is connected (S26). In this way, as shown by the alternate long and short dash line in FIG. 5B, for example, the sensor nodes 112 having the number of hops "1" are connected to each other, and the sensor nodes 112 having the number of hops "2" are connected to each other.

As with the first specified value, the second specified value differs depending on the type of dwelling unit in which the meter 110 is installed. Therefore, the relative distance in step S26 also has a coefficient depending on the type of dwelling units in which the meter 110 is installed, for example, between detached houses, between detached houses and rebar apartment houses, or between rebar apartment houses. It may be determined by multiplying (weighting).

Note that the sensor nodes 112 having N + 1 hops are not always connected to each other, unlike the sensor nodes 112 having N + 1 hops and the sensor nodes 112 having N hops. Then, regarding the connection determination between the sensor nodes 112 having the number of N + 1 hops, it should be connected to any sensor node 112 such as the sensor node 112 having the number of N + 1 hops and the sensor node 112 having the number of N hops. There is no need to adopt the idea. Therefore, for the sensor nodes 112 having N + 1 hops, the processes such as steps S16 to S22 in the sensor nodes 112 having N + 1 hops and the sensor nodes 112 having N hops are not performed.

The topology control unit 136 determines whether or not the processes of steps S10 to S26 have been performed for all the sensor nodes 112 on the sensor network 100 having the same network ID (S28). As a result, if the processes of steps S10 to S26 have been performed for all the sensor nodes 112 (YES in S28), the topology control unit 136 ends the topology estimation method. If steps S10 to S26 have not been performed for all the sensor nodes 112 (NO in S28), the topology control unit 136 repeats the process (S10) of extracting the sensor node 112 having a new N + 1 hop number.

The topology estimation method by the topology control unit 136 makes it possible to appropriately estimate the topology of the sensor network 100.

Further, here, the topology as shown in FIG. 5B is referred to, and the route through which the sensor node 112 is connected can be grasped. Further, it is possible to specify a specific route or long-distance propagation from the positional relationship of the sensor node 112.

Here, as shown in FIG. 5B, the specific route is a route that does not have a detour route, that is, a route that the sensor node 112 downstream of the route cannot communicate with the upstream repeater 114 unless the route is passed. To tell. Further, a terminal upstream of a specific route may be referred to as a specific route terminal.

Since there is a high possibility that many sensor nodes 112 are connected to the specific route terminal downstream, the power consumption tends to increase, and the influence becomes large at the time of failure. On the other hand, since the specific route terminal can easily grasp the number of downstream sensor nodes 112, the power consumption can be easily distributed by rearranging the sensor network 100, and the sensor nodes 112 affected by the failure can be easily grasped.

Long-distance propagation refers to a route having a relative distance of a predetermined value (for example, 50 m) or more, as shown in FIG. 5 (b). Further, a terminal upstream of long-distance propagation may be referred to as a long-distance propagation terminal.

Long-distance propagation can reduce the communication success rate. If the communication success rate of the long-distance propagation terminal, that is, the sensor node 112 upstream of the long-distance propagation is high, and the communication success rate of the sensor node 112 downstream of the long-distance propagation is low, the cause is that the long-distance transmission is wireless. It is conceivable that the radio wave will fluctuate due to the connection with.

With such a configuration, it becomes possible to estimate the topology of the sensor network 100 with high accuracy.

It should be noted that each process described with reference to FIG. 6 does not necessarily have to be processed in chronological order according to the order shown in the flowchart, and the order may be changed. In the meantime, parallel or subroutine processing can be included.

(Maintenance system according to the second embodiment)
The topology of the sensor network 100 is estimated by the above topology estimation system. The topology estimation system also identifies specific routes and long-distance propagation. In such a sensor network 100, for example, a situation may occur in which it becomes difficult to make a wireless connection between the sensor nodes 112, and some devices may require maintenance. However, it is not easy to accurately grasp the equipment that requires maintenance.

Therefore, as shown in FIG. 1, the maintenance system 1 of the sensor network 100 of the present embodiment includes the maintenance device 150. The maintenance device 150 can establish communication with the center device 116 and can acquire necessary information from the center holding unit 124 of the center device 116.

FIG. 9 is a functional block diagram showing a schematic configuration of the maintenance device 150. The maintenance device 150 includes a maintenance communication unit 152, a maintenance holding unit 154, and a maintenance control unit 156.

The maintenance communication unit 152 establishes communication with the center device 116 by wired communication or wireless communication. The maintenance holding unit 154 is composed of a RAM, a flash memory, an HDD, and the like. The maintenance holding unit 154 holds various information such as information included in the meter database and information on conduit mapping acquired from the center device 116 through the maintenance communication unit 152. The maintenance control unit 156 is composed of a processor and a memory for storing a program. The maintenance control unit 156 functions as a functional module such as the maintenance control unit 156 by executing a program by the processor.

The maintenance control unit 156 controls the maintenance of the sensor network 100, which will be described in detail later. The maintenance control unit 156 acquires information necessary for performing control related to maintenance from the center device 116 and stores it in the maintenance holding unit 154. The maintenance control unit 156 controls maintenance by referring to the information stored in the maintenance holding unit 154.

Here, the maintenance control unit 156 sets any one of the plurality of meters 110 as the target meter to be determined for maintenance, and the sensor node 112 corresponding to the target meter as the target sensor node. Further, since the meter 110 and the sensor node 112 are associated with each other, for convenience of explanation, establishing communication with the sensor node 112 may be expressed as establishing communication with the meter 110. Similarly, attaching the repeater 114 to the sensor node 112 may be expressed as attaching the repeater 114 to the meter 110.

The maintenance control unit 156 determines whether or not the communication success rate of the target meter is less than a predetermined value. The communication success rate of the target meter indicates the ratio of the number of successful communications to the number of communication attempts between the target meter and the center device 116. If the communication success rate is less than a predetermined value, the maintenance control unit 156 determines whether or not the repeater 114 is attached to the target meter (more accurately, the target sensor node). If the repeater 114 is attached, the maintenance control unit 156 determines whether communication is established in the order of the repeater 114 and the target sensor node.

In this way, the maintenance control unit 156 determines the necessity of maintenance and the content of maintenance by performing determinations in a plurality of stages with respect to the target meter. Then, the maintenance control unit 156 sequentially changes the target meter, and makes a determination in a plurality of stages for each of the plurality of meters 110. As a result, the maintenance control unit 156 can extract the meter 110 that requires maintenance and can determine the coping method.

Further, if the repeater 114 is not attached to the target meter, the maintenance control unit 156 determines whether or not the failure of the load survey of the target meter continues for a predetermined number of days or more. The load survey is that the center device 116 collects information on the meter 110. The failure of the load survey corresponds to the fact that the information of the meter 110 could not be collected because the communication between the center device 116 and the meter 110 could not be established. If the failure of the load survey continues for a predetermined number of days or more, the maintenance control unit 156 determines whether or not the repeater 114 is connected to the sensor node 112 upstream of the target meter. On the other hand, if the failure of the load survey is less than the predetermined number of days, the maintenance control unit 156 determines whether or not the communication success rate difference is equal to or greater than the predetermined value. The communication success rate difference is the difference between the communication success rate of the meter 110 corresponding to the sensor node 112 one hop upstream of the target sensor node and the communication success rate of the target meter.

As described above, the maintenance control unit 156 can determine the necessity of maintenance more accurately by further adding the determination condition. Hereinafter, the operation flow of the maintenance control unit 156 according to the second embodiment will be described in detail.

10 to 16 are flowcharts illustrating an operation flow of the maintenance control unit 156 according to the second embodiment. The "A" in FIG. 10 follows the "A" in FIG. "B" in FIG. 11 follows "B" in FIG. The “C” in FIG. 11 follows the “C” in FIG. The "D" in FIG. 13 follows the "D" in FIG. The "E" in FIG. 14 follows the "E" in FIG. The "F" in FIG. 15 follows the "F" in FIG.

The maintenance control unit 156 executes a series of processes of FIGS. 10 to 16 with any one of the plurality of meters 110 as a target meter at a predetermined timing repeated at a predetermined cycle (for example, every day). Then, the maintenance control unit 156 sequentially changes the target meters, and executes a series of processes of FIGS. 10 to 16 for all the target meters.

First, as shown in FIG. 10, the maintenance control unit 156 determines whether or not the target meter is entering the sensor network 100 and the communication success rate of the target meter is less than a predetermined value (S10). .. Here, if any repeater ID is associated with the meter ID of the target meter in the meter database, the maintenance control unit 156 determines that the target meter is entering the sensor network 100. On the other hand, if no repeater ID is associated with the meter ID of the target meter, the maintenance control unit 156 determines that the target meter is separated from the sensor network 100 (not entering). In other words, entering the network means that the meter (more specifically, the sensor node corresponding to the meter) is in a state where communication is possible through the repeater 114. Further, the maintenance control unit 156 can acquire the communication success rate of the target meter from the meter database. The predetermined value is set to, for example, 98%, but can be arbitrarily set depending on the specifications of the sensor node 112, the installation position of the sensor node 112, and the like.

If the target meter is separated from the sensor network 100, or if the communication success rate of the target meter is equal to or higher than a predetermined value (NO in S10), the maintenance control unit 156 determines whether or not the setting of the target meter has failed. Is determined (S11). Here, in the initial state, the meter 110 is set so that the load survey function is not enabled and the load survey is not performed. Therefore, after the meter 110 is installed, the center device 116 sets the activation of the load survey function of the meter 110 to be turned on by remote control, and also sets the start timing of the load survey. Specifically, in step S11, it is determined whether or not such a load survey function is enabled and the load survey start timing is set.

If the setting of the target meter has failed (YES in S11), the maintenance control unit 156 presents maintenance for resetting the target meter by remote control from the center device 116 (S12), and the target meter is about the target meter. Ends the processing of. When the setting of the target meter has not failed (NO in S11), the maintenance control unit 156 presents the maintenance of the content to be the follow-up observation (S13), and ends the process for the target meter. Follow-up is to watch the situation without doing anything this time.

When the target meter is entering the sensor network 100 and the communication success rate of the target meter is less than a predetermined value (YES in S10), the maintenance control unit 156 has a repeater 114 attached to the target sensor node. It is determined whether or not it is present (S14). For example, in the meter database, repeater attachment information indicating whether or not the repeater 114 is attached to the sensor node 112 corresponding to the meter 110 is associated with the meter ID. The maintenance control unit 156 can determine whether or not the repeater 114 is attached to the target sensor node corresponding to the target meter by referring to the repeater attachment information.

When the repeater 114 is attached to the target meter (YES in S14), the maintenance control unit 156 determines whether or not communication between the center device 116 and the repeater 114 is established (S15). Here, the maintenance control unit 156 may cause the center device 116 to actually try communication addressed to the repeater 114, or may refer to the latest communication history stored in the center holding unit 124.

When communication between the center device 116 and the repeater 114 is not established (NO in S15), the maintenance control unit 156 presents maintenance related to the repeater 114 (S16), and ends the process for the target meter. Specifically, the maintenance control unit 156 presents maintenance for replacing the repeater 114 because the repeater 114 is defective.

When the communication between the center device 116 and the repeater 114 is established (YES in S15), the maintenance control unit 156 determines whether or not the communication between the center device 116 and the target sensor node is established (S17). Here, the maintenance control unit 156 may cause the center device 116 to actually try communication addressed to the target sensor node, or may refer to the latest communication history stored in the center holding unit 124.

When communication between the center device 116 and the target meter is not established (NO in S17), the maintenance control unit 156 presents maintenance related to the target sensor node or the target meter (S18), and ends the process for the target meter. Specifically, the maintenance control unit 156 presents maintenance for replacing the target sensor node or the target meter because the target sensor node or the target meter is defective. Further, the maintenance control unit 156 may present maintenance to the effect that the connection between the target sensor node and the target meter is defective. Further, the maintenance control unit 156 may present that a worker for investigating the detailed maintenance contents of the target sensor node or the target meter is dispatched to the site.

When communication between the center device 116 and the target sensor node is established (YES in S17), the maintenance control unit 156 determines whether or not the setting information about the target meter is retransmitted from the center device 116 to the target meter. (S19).

When the setting information about the target meter is retransmitted (YES in S19), the maintenance control unit 156 presents maintenance for replacing the repeater 114 because the repeater 114 upstream of the target meter is defective (S20). Then, the processing for the target meter is terminated. The maintenance control unit 156 is not limited to replacing the repeater 114, and may present maintenance for setting the set values of the repeater 114, the sensor node 112, or the meter 110 by remote control.

When the setting for the target meter is not retransmitted (NO in S19), the maintenance control unit 156 determines whether or not the target meter is a meter 110 not to be monitored (S21). The meter 110 that is not subject to monitoring is a meter 110 that has a contract not to perform a load survey.

When the target meter is a meter 110 that is not subject to monitoring (YES in S21), the maintenance control unit 156 ends the process for the target meter. When the target meter is not the meter 110 not subject to monitoring (NO in S21), the maintenance control unit 156 presents maintenance for resetting the target meter by remote control from the center device 116 (S22), and the target is concerned. End the processing for the meter.

In step S14, when the repeater 114 is not attached to the target meter (NO in S14), the maintenance control unit 156 proceeds to “A” and performs the processing after “A” in FIG.

As shown in FIG. 11, the maintenance control unit 156 that has advanced to “A” determines whether or not the failure of the load survey of the target meter continues for a predetermined number of days or more (S30). For example, in the meter database, load survey information indicating the success or failure result of the daily load survey is associated with the meter ID. The maintenance control unit 156 refers to this load survey information, derives the number of continuous days of load survey failure, and compares the derived number of continuous days with the predetermined number of days. The predetermined number of days is set to, for example, 7 days, but can be arbitrarily set depending on the specifications of the sensor node 112, the installation position of the sensor node 112, and the like.

When the failure of the load survey of the target meter continues for a predetermined number of days or more, in other words, when the failure of the load survey continues for a predetermined number of days or more (YES in S30), the maintenance control unit 156 performs the process of step S31. move on. On the other hand, when the failure of the load survey of the target meter does not continue for a predetermined number of days or more, in other words, when the failure of the load survey continues for less than a predetermined number of days (NO in S30), the maintenance control unit 156 steps. Proceed to the process of S37.

In step S31, the maintenance control unit 156 determines whether or not the repeater 114 is connected to the sensor node 112 upstream of the target meter (S31). The determination in step S31 corresponds to determining whether the repeater 114 upstream of the target meter has been removed. For example, in the meter database, construction information showing the history of various works such as the date when the repeater 114 is attached and the date when the repeater 114 is removed is associated with the meter ID. The maintenance control unit 156 has a history of removing the repeater 114 around the installation position of the target meter, and if there is no history of installing the repeater 114 after that, the repeater 114 is connected to the upstream of the target meter. It can be determined that it has not been done.

When the repeater 114 is not connected to the sensor node 112 upstream of the target meter (NO in S31), the maintenance control unit 156 restarts the sensor node 112 under the removed repeater 114, or restarts the sensor node 112. Maintenance of the content of attaching the removed repeater 114 to the predetermined sensor node 112 is presented (S32), and the process for the target meter is terminated. When the sensor node 112 is restarted, the restarted sensor node 112 can enter the network of another repeater 114 if there is a network of another repeater 114 in the vicinity. Also, when the removed repeater 114 is reattached to the sensor node 112, the network before the repeater 114 was removed can be restored. The repeater 114 is attached to the sensor node 112 that was attached before the removal, but may be attached to another sensor node 112 around the sensor node 112 that was attached before the removal.

When the repeater 114 is connected to the sensor node 112 upstream of the target meter (YES in S31), the maintenance control unit 156 determines whether or not communication between the center device 116 and the target sensor node is established (YES in S31). S33). Here, the maintenance control unit 156 may cause the center device 116 to actually try communication addressed to the target sensor node, or may refer to the latest communication history stored in the center holding unit 124.

When communication between the center device 116 and the target sensor node is not established (NO in S33), the maintenance control unit 156 presents maintenance related to the target sensor node (S34), and ends the process for the target meter. Specifically, the maintenance control unit 156 may present maintenance of the content that the target sensor node is defective, or may present maintenance of the content that the battery voltage of the target sensor node has dropped.

When communication between the center device 116 and the target sensor node is established (YES in S33), the maintenance control unit 156 determines whether or not the setting information about the target meter is retransmitted to the target meter (S35). When the setting information about the target meter is not retransmitted (NO in S35), the maintenance control unit 156 presents maintenance for resetting the target meter by remote control from the center device 116 (S36), and the target is concerned. The processing for the meter is finished. When the setting information about the target meter is retransmitted (YES in S35), the maintenance control unit 156 proceeds to the process of step S37.

In step S37, the maintenance control unit 156 determines whether or not the communication success rate difference indicating the difference between the communication success rate of the meter 110 one hop upstream of the target meter and the communication success rate of the target meter is equal to or greater than a predetermined value. (S37). The communication success rate difference indicates the degree of decrease in the communication success rate of the target meter with respect to the communication success rate of the meter 110 one hop upstream. The communication success rate of the target meter is almost the same as the communication success rate of the target sensor node. The communication success rate of the meter 110 one hop upstream of the target meter is substantially the same as the communication success rate of the sensor node 112 one hop upstream of the target sensor node. For example, the maintenance control unit 156 refers to the meter database, subtracts the communication success rate of the target meter from the communication success rate of the meter 110 one hop upstream, and derives the communication success rate difference. Compare the communication success rate difference with the predetermined value. The predetermined value is set to, for example, 2%, but is not limited to this example, and can be arbitrarily set depending on the specifications of the sensor node 112, the installation position of the sensor node 112, and the like.

When the communication success rate difference is equal to or greater than a predetermined value (YES in S37), the maintenance control unit 156 determines whether or not the sensor node 112 upstream of the target sensor node is a specific route terminal or a long-distance propagation terminal (YES in S37). S38). As described above, the specific route terminal is arranged so that the sensor node 112 downstream of the specific route terminal cannot communicate with the upstream repeater 114 without passing through the specific route terminal. Is shown. Further, as described above, the long-distance propagation terminal indicates a sensor node 112 whose relative distance to the sensor node 112 downstream of the specific route terminal is a predetermined value (for example, 50 m) or more. Such specific route terminals and long-distance propagation terminals are specified by the above-mentioned topology estimation system.

When the sensor node 112 upstream of the target sensor node is a specific route terminal or a long-distance propagation terminal (YES in S38), the maintenance control unit 156 proceeds to "B" and performs the processing after "B" in FIG. .. On the other hand, when the communication success rate difference is less than a predetermined value (NO in S37), or when the sensor node 112 upstream of the target sensor node is not a specific route terminal or a long-distance propagation terminal (NO in S38). The maintenance control unit 156 proceeds to "C" and performs the processing after "C" in FIG.

As shown in FIG. 12, the maintenance control unit 156 that has advanced to “B” determines whether or not a meter 110 different from the target meter exists within a predetermined distance from the target meter (S40). Specifically, the maintenance control unit 156 extracts the meter 110 around the installation position of the target meter by referring to the information of the conduit mapping, and the installation position of the meter 110 and the target meter extracted for each extracted meter 110. The distance from the installation position of is derived, and the derived distance is compared with the predetermined distance. If the derived distance is equal to or less than a predetermined distance, the maintenance control unit 156 determines that another meter 110 exists within a predetermined distance from the target meter. The predetermined distance is, for example, 30 m, but can be arbitrarily set in consideration of the distance at which wireless communication of the sensor node 112 is possible.

If a meter 110 other than the target meter does not exist within a predetermined distance from the target meter (NO in S40), the maintenance control unit 156 retrofits the repeater 114 or performs maintenance to reconstruct the network. Present (S41), and end the processing for the target meter. The repeater 114 is retrofitted to the extent that the target meter can communicate with the center device 116 through the repeater 114. For network reconstruction, for example, the target meter, the target sensor node, or the repeater 114 upstream of the target meter is remotely restarted from the center device 116. For example, when the repeater 114 is restarted, the repeater 114 reassigns the sensor node 112, so that a more appropriate sensor node 112 is placed under the repeater 114 as compared to before the restart. It is possible to improve the communication success rate of the target meter.

When a meter 110 different from the target meter exists within a predetermined distance from the target meter (S40), the maintenance control unit 156 determines whether or not the sensor node 112 is attached to the existing meter 110 (S42). ). Since the meter to which the sensor node 112 is not attached is not a smart meter, this determination corresponds to the determination of whether or not the existing meter 110 is a smart meter.

When the sensor node 112 is not attached to the existing meter 110 (NO in S42), the maintenance control unit 156 presents maintenance for waiting for the meter 110 around the target meter to reach full inspection (S43). , Ends the processing for the target meter. The waiting for the inspection of the surrounding meter 110 is substantially the same as the follow-up observation because the sensor node 112 that can communicate with the target sensor node waits until it occurs around the target sensor node.

When the sensor node 112 is attached to the existing meter 110 (YES in S42), the maintenance control unit 156 presents maintenance for reconstructing the network (S44), and ends the process for the target meter. In this case, since the sensor node 112 different from the target sensor node is around the target meter, the target sensor node is restarted. As a result, the target sensor node can be separated from the currently connected upstream sensor node 112, and the target sensor node can be connected to the other sensor node 112, thereby improving the communication success rate of the target sensor node. Is possible.

Further, as shown in FIG. 13, the maintenance control unit 156 advancing to “C” determines whether or not the building in which the target meter is installed is a reinforced apartment house having a predetermined number of units or more (S50). The predetermined number of units is, for example, 20 units, but it can be arbitrarily set in consideration of the allowable value of the number of sensor nodes 112 that can be assigned to one repeater 114.

When the building in which the target meter is installed is a reinforced apartment house with a predetermined number of units or more (YES in S50), the maintenance control unit 156 determines whether or not the repeater 114 upstream of the target meter is in the building. (S51). This is the same as determining whether or not the target meter has entered the network of repeaters 114 in the building.

When the repeater 114 upstream of the target meter is not in the building (NO in S51), the maintenance control unit 156 determines whether or not the repeater 114 is sufficiently installed in the building (S52). Specifically, the maintenance control unit 156 divides the number of units in the building (in other words, the total number of meters 110) by the number of repeaters 114 in the building, and divides the number of repeaters 114 in the building. Derived the number of allocations indicating the number of sensor nodes 112 assigned to. In the repeater 114, the permissible value of the number of sensor nodes 112 that can be assigned is predetermined. Therefore, the smaller the number of allocations here, the more room for allocation in the repeater 114, and the repeater in the building. It shows that many 114 are installed. If the derived allocation number is less than a predetermined value, the maintenance control unit 156 determines that the repeater 114 is sufficiently installed. The predetermined value is, for example, 30, but can be arbitrarily set in consideration of the allowable value of the number of sensor nodes 112 that can be assigned to one repeater 114.

When the repeater 114 is sufficiently installed in the building (YES in S52), the maintenance control unit 156 presents the maintenance of the contents for reconstructing the network (S53), and ends the processing for the target meter. do. If the repeater 114 is not sufficiently installed in the building (NO in S52), the maintenance control unit 156 presents maintenance for retrofitting the repeater 114 (S54), and performs processing on the target meter. finish.

In step S51, when the repeater 114 upstream of the target meter is in the building (YES in S51), the maintenance control unit 156 is equipped with the target sensor node and the repeater 114 upstream of the target sensor node. It is determined whether or not the number of hops with the sensor node 112 is equal to or greater than the predetermined number of hops (S55). The predetermined number of hops is, for example, 4 hops, but can be arbitrarily set depending on the specifications of the sensor node 112, the installation position of the sensor node 112, and the like.

When the number of hops is equal to or greater than the predetermined number of hops (YES in S55), the maintenance control unit 156 presents maintenance for reconstructing the network (S56), and ends the process for the target meter.

When the number of hops is less than the predetermined number of hops (NO in S55), the maintenance control unit 156 determines whether or not the target sensor node has frequently entered the network (S57). Entering the network withdrawal indicates that the target sensor node is disconnected from the control of the repeater 114 upstream of the target sensor node, or the target sensor node joins the control of another repeater 114. When the sensor node 112 enters the network, the network ID of the network is associated with the meter ID of the meter 110 corresponding to the sensor node 112 in the meter database. Further, when the sensor node 112 leaves the network, the association between the meter ID and the network ID is released. Therefore, the maintenance control unit 156 can determine whether or not the network exit entry occurs frequently by referring to the meter database and acquiring the time transition of the association of the network ID in the target meter. Frequent occurrence means that the frequency of network withdrawal entry is higher than the general predetermined frequency of occurrence, and specifically, the number of occurrence of network withdrawal entry within a predetermined period is more than a predetermined number of times. The predetermined period is, for example, one month, but can be arbitrarily set. The predetermined number of times is, for example, 5 times, but can be arbitrarily set depending on the specifications of the sensor node 112, the installation position of the sensor node 112, and the like.

When the network exit entry does not occur frequently (NO in S57), the maintenance control unit 156 acquires the operation information of the target meter or the target sensor node by remote control from the center device 116 and presents the maintenance of the content that needs to be examined. (S58), the process for the target meter is terminated. The operation information is log information of various communication histories such as the cumulative number of communication successes and the cumulative number of communication failures in the sensor node 112, and is stored in the internal memory of the sensor node 112. The operation information of the target meter or the target sensor node is used when considering further specific maintenance.

When the network exit entry occurs frequently (YES in S57), the maintenance control unit 156 acquires the operation information of the target meter or the target sensor node and performs maintenance of the content that needs to be examined, or the content of retrofitting the repeater 114. Maintenance is presented (S59), and the processing for the target meter is terminated.

In step S50, when the building in which the target meter is installed is not a reinforcing bar apartment house of a predetermined number or more (NO in S50), the maintenance control unit 156 proceeds to "D" and processes after "D" in FIG. I do.

As shown in FIG. 14, the maintenance control unit 156 that has advanced to “D” determines whether or not the building in which the target meter is installed is a reinforced apartment house with less than a predetermined number of units (S60). The predetermined house here is set to be the same as the predetermined house in step S50.

When the building in which the target meter is installed is a reinforced apartment building with less than a predetermined unit (YES in S60), the maintenance control unit 156 determines whether or not the repeater 114 is installed in the building (S61). ).

When the repeater 114 is not installed in the building (NO in S61), the maintenance control unit 156 determines whether or not a meter 110 different from the target meter exists within a predetermined distance from the target meter. (S62).

If there is no meter 110 other than the target meter within a predetermined distance from the target meter (NO in S62), the maintenance control unit 156 presents maintenance for retrofitting a repeater or reconstructing the network. (S63), the process for the target meter is terminated.

When a meter 110 different from the target meter exists within a predetermined distance from the target meter (YES in S62), the maintenance control unit 156 determines whether or not the sensor node 112 is attached to the existing meter 110 (YES in S62). S64).

When the sensor node 112 is not attached to the existing meter 110 (NO in S64), the maintenance control unit 156 presents maintenance for waiting for the meter 110 around the target meter to reach full inspection (S65). , Ends the processing for the target meter. When the sensor node 112 is attached to the existing meter 110 (YES in S64), the maintenance control unit 156 presents maintenance for reconstructing the network (S66), and ends the process for the target meter.

In step S61, when the repeater 114 is installed in the building (YES in S61), the maintenance control unit 156 determines whether or not the repeater 114 upstream of the target meter is in the building (YES in S61). S67).

If the repeater 114 upstream of the target meter is not in the building (NO in S67), the maintenance control unit 156 presents maintenance to reconstruct the network (S68), and ends the processing for the target meter. do.

When the repeater 114 upstream of the target meter is in the building (YES in S67), the maintenance control unit 156 includes the target sensor node and the sensor node 112 to which the repeater 114 upstream of the target sensor node is attached. It is determined whether or not the number of hops between is equal to or greater than the predetermined number of hops (S69). The predetermined number of hops is set to be the same as the predetermined number of hops in step S55. When the number of hops is equal to or greater than the predetermined number of hops (YES in S69), the maintenance control unit 156 presents maintenance for reconstructing the network (S70), and ends the process for the target meter.

When the number of hops is less than the predetermined number of hops (NO in S70), the maintenance control unit 156 determines whether or not the target sensor node has frequently entered the network (S71). When the network exit entry does not occur frequently (NO in S57), the maintenance control unit 156 acquires the operation information of the target meter or the target sensor node and presents the maintenance of the content that needs to be examined (S72), and the target meter. Ends the processing for. When the network exit entry occurs frequently (YES in S71), the maintenance control unit 156 acquires the operation information of the target meter or the target sensor node and requires maintenance, or the content of retrofitting the repeater 114. Maintenance is presented (S59), and the processing for the target meter is terminated.

In step S60, when the building in which the target meter is installed is not a reinforced apartment house with less than a predetermined unit (NO in S50), it can be considered that the building is not a reinforced apartment house but a detached house or a wooden apartment house. In this case, the maintenance control unit 156 proceeds to "E" and performs the processing after "E" in FIG.

As shown in FIG. 15, the maintenance control unit 156 that has advanced to “E” determines whether or not the sensor node 112 one hop upstream of the target sensor node is installed in the reinforcing bar apartment (S80). This is a determination of whether or not the sensor node 112 corresponding to the meter 110 installed in the reinforcing bar apartment building is upstream of the target meter, and the upstream sensor node 112 and the target sensor node are in direct communication. Corresponds to.

When the sensor node 112 one hop upstream is installed in the reinforcing bar apartment (YES in S80), the maintenance control unit 156 is the meter 110 (reinforcing bar apartment house) corresponding to the sensor node 112 one hop upstream of the target sensor node. It is determined whether or not the communication success rate difference indicating the difference between the communication success rate of the meter 110) inside and the communication success rate of the target meter (meter 110 outside the reinforcing bar apartment house) is equal to or more than a predetermined value (S81). ).

When the communication success rate difference is equal to or greater than a predetermined value (YES in S81), the maintenance control unit 156 has a repeater 114 in the reinforcing bar apartment house in which the sensor node 112 one hop upstream of the target sensor node is installed. It is determined whether or not to do so (S82).

When the repeater 114 exists in the reinforcing bar apartment (YES in S82), the maintenance control unit 156 determines whether or not a meter 110 different from the target meter exists within a predetermined distance from the target meter. (S83).

When a meter 110 different from the target meter exists within a predetermined distance from the target meter (YES in S83), the maintenance control unit 156 determines whether or not the sensor node 112 is attached to the existing meter 110 (YES in S83). S84).

When the sensor node 112 is attached to the existing meter 110 (NO in S84), the maintenance control unit 156 presents maintenance of the content for reconstructing the network (S85), and ends the process for the target meter. ..

If a meter 110 different from the target meter does not exist within a predetermined distance from the target meter (NO in S83), or the other meter 110 exists but the sensor node 112 is not attached to the existing meter 110. In the case (NO in S84), the maintenance control unit 156 presents maintenance for the content of waiting for the meters 110 around the target meter to reach full inspection (S86), and ends the processing for the target meter.

In step S80, when the sensor node 112 one hop upstream is not installed in the reinforcing bar apartment building (NO in S80), in step S81, the communication success rate difference is less than a predetermined value (NO in S81), or. If the repeater 114 does not exist in the reinforcing bar apartment building in step S82 (NO in S82), the maintenance control unit 156 proceeds to “F” and performs the processing after “F” in FIG.

As shown in FIG. 16, the maintenance control unit 156 that has advanced to “F” determines whether or not the target sensor node has frequently left or entered the network (S90).

When the network exit entry does not occur frequently (NO in S90), the maintenance control unit 156 has the number of hops between the target sensor node and the sensor node 112 to which the repeater 114 is attached upstream of the target sensor node. , It is determined whether or not the number of hops is equal to or greater than the predetermined number (S91).

When the number of hops is less than the predetermined number of hops (NO in S91), the maintenance control unit 156 has a distance between the target meter and the meter 110 corresponding to the sensor node 112 one hop upstream of the target sensor node. It is determined whether or not it is (S92).

When the distance is less than the predetermined distance (NO in S92), the maintenance control unit 156 acquires the operation information of the target meter or the target sensor node and presents the maintenance of the content requiring examination (S93), and the target meter. Ends the processing for.

In step S90, when network exit entry occurs frequently (YES in S90), in step S91, the number of hops is equal to or greater than the predetermined number of hops (YES in S91), or in step S92, the distance is a predetermined distance. In the above case (YES in S92), the maintenance control unit 156 determines whether or not a meter 110 different from the target meter exists within a predetermined distance from the target meter (S94).

When a meter 110 different from the target meter exists within a predetermined distance from the target meter (YES in S94), the maintenance control unit 156 determines whether or not the sensor node 112 is attached to the existing meter 110 (YES in S94). S95).

When the sensor node 112 is attached to the existing meter 110 (YES in S95), the maintenance control unit 156 presents maintenance for reconstructing the network (S96), and ends the process for the target meter.

If a meter 110 different from the target meter does not exist within a predetermined distance from the target meter (NO in S94), or the other meter 110 exists but the sensor node 112 is not attached to the existing meter 110. In the case (NO in S95), the maintenance control unit 156 presents maintenance for the content of waiting for the meters 110 around the target meter to reach full inspection (S97), and ends the processing for the target meter.

According to the maintenance system 1 according to the second embodiment, it is possible to grasp the equipment requiring maintenance in the sensor network 100. Further, in the maintenance system 1 according to the second embodiment, it is possible to grasp the contents of maintenance.

(Maintenance system according to the third embodiment)
In the second embodiment, various determinations are made using an arbitrary meter 110 of the sensor network 100 as a target meter. On the other hand, in the third embodiment, among the meters 110 installed in the apartment house (more specifically, the reinforcing bar apartment house), the meter 110 which has not entered the sensor network 100 is the target meter. Then, the maintenance control unit 156 of the third embodiment deals with the target meter by making various determinations on the target meter installed in such an apartment house and not entering the sensor network 100. Present the maintenance of.

In the second embodiment, the determination regarding the reinforcing bar apartment house is made in step S50 and step S60, but it is premised that the target meter has entered the sensor network 100 in step S10 in the first place. On the other hand, the third embodiment is different from the second embodiment in that the meter 110, which has not entered the sensor network 100, is the target meter. Hereinafter, the maintenance control unit 156 according to the third embodiment will be described.

The maintenance control unit 156 uses a meter installed in an apartment house and not entering the sensor network 100 as a target meter, and a sensor node 112 corresponding to the target meter as a target sensor node. If there are a plurality of meters installed in an apartment house and not participating in the sensor network 100, one of the meters 110 will be the target meter.

Here, the index obtained by dividing the number of meters 110 to which the sensor node 112 is associated in the apartment house by the total number of meters 110 including the meter 110 to which the sensor node 112 is not associated in the apartment house is a meter. The installation rate. The number of meters 110 to which the sensor node 112 is associated corresponds to the number of smart meters. The meter installation rate corresponds to the ratio of the number of meters on which the sensor node 112 is installed to the total number of meters in the apartment house in which the target meter is installed.

Further, the index obtained by dividing the number of units in the apartment house by the number of repeaters 114 in the apartment house is taken as an allocation number indicating the number of sensor nodes 112 assigned to one repeater 114 in the apartment house. .. Further, the ratio of the number of sensor nodes 112 capable of communicating with the center device 116 in the apartment house to the total number of sensor nodes 112 installed in each house of the apartment house is defined as the network entry rate.

Further, in the sensor network 100, in an apartment house having a predetermined number of units or more, the design is such that one or more repeaters 114 are installed in the apartment house. If the repeater 114 is not currently installed in the apartment house, the repeater 114 will be installed in the apartment house in the future. Further, in an apartment house where the number of units is less than a predetermined number, basically, the design is such that the repeater 114 is not installed in the apartment house. However, depending on the case, the repeater 114 may be installed in the apartment house. The predetermined number of units is, for example, 20 units, but it can be arbitrarily set in consideration of the allowable value of the number of sensor nodes 112 that can be assigned to one repeater 114.

As described above, the design policy regarding the installation of the repeater 114 differs depending on the number of units in the apartment house. Therefore, the maintenance control unit 156 makes the processing flow different depending on whether the number of apartments in which the target meter is installed is more than or less than the predetermined number of units or less than the predetermined number of units.

When the number of apartments in which the target meter is installed is equal to or greater than the predetermined number, the maintenance control unit 156 determines whether or not the meter installation rate in the apartment is equal to or greater than the predetermined first threshold value. If the meter installation rate is equal to or higher than the first threshold value, the maintenance control unit 156 determines whether or not the number of allocations in the apartment house is equal to or lower than the predetermined second threshold value. If the allocated number is equal to or less than the second threshold value, the maintenance control unit 156 determines whether or not the network entry rate in the apartment house is less than the third threshold value.

In this way, the maintenance control unit 156 determines the target meter in a plurality of stages, and determines the necessity of maintenance and the content of maintenance. If there are a plurality of meters installed in an apartment house and not participating in the sensor network 100, the target meters are sequentially changed, and each of the plurality of meters is judged in multiple stages. go. As a result, the maintenance control unit 156 can extract the meters that require maintenance and determine the coping method.

Further, when the number of apartments in which the target meter is installed is less than the predetermined number, the maintenance control unit 156 determines whether or not the meter installation rate in the apartment is equal to or higher than the predetermined seventh threshold value. do. If the meter installation rate is equal to or higher than the seventh threshold value, the maintenance control unit 156 determines whether or not the repeater 114 is installed in the apartment building. If the repeater 114 is installed in the apartment house, the maintenance control unit 156 determines whether or not the network entry rate in the apartment house is less than a predetermined eighth threshold value.

As described above, the maintenance control unit 156 can determine the necessity of maintenance more accurately by further adding the determination condition. Hereinafter, the operation flow of the maintenance control unit 156 according to the third embodiment will be described in detail.

17 to 22 are flowcharts illustrating an operation flow of the maintenance control unit 156 according to the third embodiment. The “G” in FIG. 17 follows the “G” in FIG. The “H” in FIG. 18 follows the “H” in FIG. The "I" in FIG. 17 follows the "I" in FIG. 20. The “J” in FIG. 20 follows the “J” in FIG. 21. The “K” in FIG. 21 follows the “K” in FIG. 22.

When the maintenance control unit 156 reaches a predetermined timing that is repeated at a predetermined cycle (for example, every day), the maintenance control unit 156 is a series of FIGS. 17 to 22 with one meter 110 that has not entered the sensor network 100 in the apartment house as a target meter. Executes the processing of. Then, the maintenance control unit 156 sequentially changes the target meters, and executes a series of processes of FIGS. 17 to 22 for all the target meters.

First, as shown in FIG. 17, the maintenance control unit 156 determines whether or not the number of units in the apartment house in which the target meter is installed is a predetermined number of units (for example, 20 units) or more (S100). The number of apartments can be obtained, for example, by referring to the information of the conduit mapping. When the number of the units is less than the predetermined number (NO in S100), the maintenance control unit 156 proceeds to "I". The details after "I" will be described later.

When the number of the units is equal to or greater than the predetermined number (YES in S100), the maintenance control unit 156 determines whether or not the meter installation rate in the apartment house in which the target meter is installed is equal to or greater than the predetermined first threshold value. (S101). The first threshold value is, for example, 80%, but can be arbitrarily set in consideration of the scale of the sensor network 100 and the like.

When the meter installation rate is less than the first threshold value (NO in S101), the maintenance control unit 156 presents maintenance of the content of waiting for the meter 110 around the target meter to reach full inspection (S102), and the target is concerned. End the processing for the meter.

When the meter installation rate is equal to or higher than the first threshold value (YES in S101), the maintenance control unit 156 has a predetermined number of allocations indicating the number of sensor nodes 112 assigned to one repeater 114 in the apartment building. It is determined whether or not it is 2 threshold values or less (S103). Specifically, the maintenance control unit refers to the meter database and the information of the conduit mapping, divides the number of units in the apartment house by the number of repeaters 114 in the apartment house, derives the allocation number, and derives it. Compare the number of allocations with the second threshold. The second threshold value is, for example, 30, but can be arbitrarily set in consideration of the allowable value of the number of sensor nodes 112 that can be assigned to one repeater 114. If the allocated number is equal to or less than the second threshold value, it corresponds to that the repeater 114 is sufficiently installed in the apartment house.

When the allocated number is larger than the second threshold value, that is, when the repeater 114 is not sufficiently installed (NO in S103), the maintenance control unit 156 determines whether or not the target meter is a property in which the repeater cannot be installed. (S104). The property in which the repeater cannot be installed is the meter 110 in which the repeater 114 cannot be attached because there is no space for attaching the repeater 114 at the installation location of the meter 110. Information on whether or not the property cannot be installed with a repeater can be obtained by referring to, for example, the construction information in the meter database.

When the target meter is a property where the repeater cannot be installed (YES in S104), the maintenance control unit 156 presents the maintenance of the content of retrofitting the repeater 114 to the meter 110 adjacent to the target meter (S105), and the target meter. Ends the processing for. The adjacent meter 110 is, for example, the meter 110 closest to the target meter, but may be any meter 110 within a predetermined distance from the target meter. Further, the maintenance control unit 156 may reconstruct the network after installing the repeater 114. For network reconstruction, for example, the target meter, the target sensor node, or the repeater 114 upstream of the target meter is remotely restarted from the center device 116.

If the target meter is not a property where the repeater cannot be installed, that is, there is space to install the repeater 114 (NO in S104), the maintenance control unit 156 plans to install the repeater 114 in the apartment house in the future. Whether or not it is determined (S106).

If there is a plan to install the repeater 114 (YES in S106), the maintenance control unit 156 presents maintenance to wait until the repeater 114 is installed according to the plan (S107), and processes the target meter. To finish.

If there is no plan to install the repeater 114 (NO in S106), the maintenance control unit 156 presents maintenance for retrofitting the repeater 114 to the target meter (S108), and ends the processing for the target meter. .. At this time, the installation status of the target meter may be confirmed by a photograph or the like.

In step S103, when the number of allocations is equal to or less than the second threshold value, that is, when the repeater 114 is sufficiently installed (YES in S103), the maintenance control unit 156 proceeds to “G” and proceeds to “G” in FIG. The subsequent processing is performed.

As shown in FIG. 18, the maintenance control unit 156 that has advanced to “G” determines whether or not the network entry rate in the apartment house is less than a predetermined third threshold value. Specifically, the maintenance control unit 156 refers to the meter database and the information of the conduit mapping, and refers to the total number of the sensor nodes 112 in the apartment house and the sensor nodes capable of communicating with the center device 116 in the apartment house. Get the number of 112. The maintenance control unit 156 divides the number of sensor nodes 112 capable of communicating with the center device 116 in the apartment house by the total number of sensor nodes 112 in the apartment house to derive the network entry rate in the apartment house. .. The third threshold value is set to, for example, 98%, but can be arbitrarily set in consideration of the scale of the sensor network 100 and the like.

When the network entry rate in the apartment house is equal to or higher than the third threshold value (NO in S110), the maintenance control unit 156 has the first average communication success rate of the meter in the apartment house less than the predetermined fourth threshold value. Whether or not it is determined (S111). The first average communication success rate is the sum of the communication success rates of the individual meters 110 to which the sensor node 112 is attached in the apartment house, for all the meters 110 to which the sensor node 112 is attached in the apartment house. It is an index obtained by dividing the total by the number of meters 110 to which the sensor node 112 is attached in the apartment house. The communication success rate of each meter 110 in the apartment house can be obtained by referring to the meter database. The fourth threshold value is set to, for example, 98%, but can be arbitrarily set depending on the installation position of the sensor node 112, the number of sensor nodes 112, and the like.

When the first average communication success rate is equal to or higher than the fourth threshold value (NO in S111), the maintenance control unit 156 has a predetermined total number of sensor nodes 112 under the repeater 114 located upstream of the target sensor node. It is determined whether or not it is the above (S112). At this time, the repeater 114 may be in the apartment house or may be outside the apartment house. Further, at this time, with respect to the sensor node 112 under the repeater 114, a part of the sensor node 112 may be located in a place other than the apartment house. The predetermined number is, for example, 30, but can be arbitrarily set in consideration of the allowable value of the number of sensor nodes 112 that can be assigned to one repeater 114.

When the total number of sensor nodes 112 under the repeater 114 located upstream of the target sensor node is equal to or greater than a predetermined number (YES in S112), the maintenance control unit 156 presents maintenance to reconstruct the network (YES in S112). S113), the process for the target meter is terminated. At this time, all the repeaters 114 and the sensor nodes 112 in the apartment house may be restarted, or some repeaters 114 or some sensor nodes 112 in the apartment house may be restarted. good. Further, at this time, the repeater 114 or the sensor node 112 other than the apartment house, which is involved in the repeater 114 or the sensor node 112 in the apartment house as well as in the apartment house, may be restarted.

When the total number of sensor nodes 112 under the repeater 114 located upstream of the target sensor node is less than a predetermined number (NO in S112), the maintenance control unit 156 presents maintenance as follow-up observation (S114). ), End the processing for the target meter.

In step S110, when the network entry rate is less than the third threshold value (YES in S110), or in step S111, the first average communication success rate is less than the fourth threshold value (YES in S111), the maintenance control unit. 156 determines whether or not the target sensor node is connected to the sensor node 112 other than the apartment house (S115). For example, the maintenance control unit 156 refers to the meter database and identifies the meter 110 corresponding to the sensor node 112 one hop upstream of the target sensor node. The maintenance control unit 156 refers to the information of the conduit mapping, and if the installation position of the meter 110 one hop upstream and the installation position of the target meter are different, the meter 110 one hop upstream is installed in a place other than the apartment house. That is, it is determined that the target sensor node is communicatively connected to the sensor node 112 other than the apartment house.

When the target sensor node is not connected to the sensor node 112 other than the apartment house (NO in S115), the maintenance control unit 156 allows the number of sensor nodes 112 under the repeater 114 in the apartment house. It is determined whether or not there is a network having the maximum value (allowable value) (S116). At this time, not only when all the sensor nodes 112 constituting the network are in the apartment house, but also when some sensor nodes 112 constituting the network are in the apartment house, the network is in the apartment house. May be determined to exist. For example, the maintenance control unit 156 extracts the meter 110 installed in the apartment house by referring to the conduit mapping and the meter database. The maintenance control unit 156 refers to the meter database and acquires the network ID corresponding to the extracted meter 110. The maintenance control unit 156 refers to the meter database and derives the number of meters 110 associated with the network ID for each acquired network ID. The number of meters 110 corresponds to the number of sensor nodes 112 under the repeater 114.

When there is a network in the apartment house in which the number of sensor nodes 112 under the repeater 114 is the maximum allowable value (YES in S116), the maintenance control unit 156 reconstructs the network. Maintenance is presented (S117), and the processing for the target meter is terminated. At this time, all the repeaters 114 in the apartment house may be restarted, or some repeaters 114 in the apartment house may be restarted.

If there is no network in the housing complex in which the number of sensor nodes 112 under the repeater 114 is the maximum allowable value (NO in S116), the maintenance control unit 156 will perform the maintenance control unit 156 in the housing complex. It is determined whether or not a radio wave has reached between the pipe shaft where the target sensor node is located and the pipe shaft where the other sensor node 112 is located (S118). For example, when the maintenance control unit 156 succeeds in communication between the center device 116 and the meter 110 corresponding to the sensor node 112 one hop upstream of the target sensor node, and the communication between the center device 116 and the target meter fails. It is judged that the radio wave does not reach between the pipe shafts. The maintenance control unit 156 may cause the center device 116 to actually try communication to the target meter, or may refer to the latest communication history stored in the center holding unit 124.

When the radio wave does not reach between the pipe shafts (YES in S118), the maintenance control unit 156 presents the maintenance of the content to be retrofitted with the repeater 114 (S119), and ends the process for the target meter.

When radio waves reach between the pipe shafts (NO in S118), the maintenance control unit 156 presents maintenance to replace the target sensor node or retrofit the repeater 114 (S120), and the target meter. Ends the processing for.

In step S115, when the target sensor node is connected to the sensor node 112 other than the apartment house (YES in S115), the maintenance control unit 156 proceeds to “H” and performs the processing after “H” in FIG. conduct.

Here, assuming that the sensor node 112 in the housing complex is connected to the sensor node 112 other than the housing complex, the group of the sensor nodes 112 under the repeater 114 upstream of the sensor node 112 in the housing complex is built. Use an external connection network. That is, the connection network outside the building includes a connection configuration in which the sensor node 112 in the housing complex is connected to the sensor node 112 other than the housing complex, and the sensor under the repeater 114 upstream of the sensor node 112 in the housing complex. The network composed of the node 112 is shown. If step S115 in FIG. 18 is YES, the target meter belongs to the out-of-building connection network because the target sensor node is connected to the sensor node 112 other than the apartment house.

As shown in FIG. 19, in the maintenance control unit 156 that has advanced to “H”, the number of meters in the apartment house among the meters 110 in the network outside the building to which the target meter belongs is equal to or less than the predetermined fifth threshold value. Whether or not it is determined (S130). For example, the maintenance control unit 156 refers to the meter database, acquires the network ID corresponding to the target meter, and extracts all the meters 110 to which the network ID is associated. The maintenance control unit 156 refers to the conduit mapping, and extracts the meter 110 in the apartment house where the target meter is installed from the meters 110 to which the network ID is associated. As a result, the number of meters in the apartment house can be derived from the sensor nodes 112 in the network connected outside the building to which the target meter belongs. The fifth threshold value is, for example, 30, but can be arbitrarily set in consideration of the allowable value of the number of sensor nodes 112 that can be assigned to one repeater 114.

When the number of meters in the apartment house exceeds the fifth threshold value (NO in S130) among the meters 110 in the network connected outside the building, the maintenance control unit 156 presents the maintenance of the contents to reconstruct the network (S131). ), End the processing for the target meter. At this time, the repeater 114 other than the apartment house, which is involved in the sensor node 112 in the apartment house, is restarted.

When the number of meters in the apartment house is equal to or less than the fifth threshold value among the meters 110 in the connection network outside the building (YES in S130), the maintenance control unit 156 is in the apartment house connected to the network other than the apartment house. It is determined whether or not the second average communication success rate of the meter 110 of the meter 110 is less than a predetermined sixth threshold value (S132). The second average communication success rate is the sum of the communication success rates of the individual meters 110 in the apartment house in the out-of-building connection network for all the meters 110 in the apartment house in the out-of-building connection network, and the derived total. It is an index divided by the number of meters 110 in the apartment house in the network connected outside the building. The sixth threshold value is set to, for example, 98%, but can be arbitrarily set depending on the specifications of the sensor node 112, the installation position of the sensor node 112, and the like.

When the second average communication success rate is equal to or higher than the sixth threshold value (NO in S132), the maintenance control unit 156 is located between the pipe shaft where the target sensor node is located and the pipe shaft where the other sensor node 112 is located. , It is determined whether or not the radio wave has arrived (S133).

When the radio wave does not reach between the pipe shafts (YES in S133), the maintenance control unit 156 presents the maintenance of the content to be retrofitted with the repeater 114 (S134), and ends the process for the target meter.

When radio waves reach between the pipe shafts (NO in S133), the maintenance control unit 156 presents maintenance to replace the target sensor node or retrofit the repeater 114 (S135), and the target meter. Ends the processing for.

In step S132, when the second average communication success rate is less than the sixth threshold value (YES in S132), the maintenance control unit 156 has two or more contacts other than the apartment house to which the sensor node 112 in the apartment house can be connected. It is determined whether or not there is (plural) (S136). The contact point here is a sensor node 112 other than the apartment house to which the sensor node 112 in the apartment house can be connected when viewed from the sensor node 112 in the apartment house connected to the network other than the apartment house. That is, if there are a plurality of contacts, the sensor node 112 in the apartment house has a plurality of routes that can be connected to the sensor node 112 other than the apartment house. On the other hand, when there is only one contact, the sensor node 112 in the apartment house cannot communicate with the center device 116 without passing through one sensor node 112 which is a contact point other than the apartment house.

When there are two or more contacts other than the apartment house to which the sensor node 112 in the apartment house can be connected (YES in S136), the maintenance control unit 156 presents maintenance of the content for reconstructing the network (S137), and the subject concerned. The processing for the meter is finished. At this time, the repeater 114 outside the apartment house is restarted.

When there is only one contact point other than the apartment house to which the sensor node 112 in the apartment house can be connected (NO in S136), the maintenance control unit 156 reconstructs the network or maintains the contents to which the repeater 114 is retrofitted. (S138), and the process for the target meter is terminated.

In step S100 of FIG. 17, when the number of units in the apartment house is less than a predetermined number (NO in S100), the maintenance control unit 156 proceeds to “I” and performs the processing after “I” in FIG. 20.

As shown in FIG. 20, the maintenance control unit 156 that has advanced to “I” determines whether or not the meter installation rate in the apartment house where the target meter is installed is equal to or higher than a predetermined seventh threshold value (. S140). The seventh threshold value is, for example, 80%, but can be arbitrarily set in consideration of the scale of the sensor network 100 and the like. The seventh threshold value may be the same as or different from the first threshold value in step S101 (see FIG. 17).

When the meter installation rate is less than the 7th threshold value (NO in S140), the maintenance control unit 156 presents maintenance for the content of waiting for the meter 110 around the target meter to reach full inspection (S141), and the target is concerned. End the processing for the meter.

When the meter installation rate is equal to or higher than the seventh threshold value (YES in S140), the maintenance control unit 156 determines whether or not one or more repeaters 114 are installed in the apartment house where the target meter is installed. (S142).

When no repeater 114 is installed in the apartment house (NO in S142), the maintenance control unit 156 determines whether or not the target meter is a property in which the repeater cannot be installed (S143).

When the target meter is a property where the repeater cannot be installed (YES in S143), the maintenance control unit 156 presents the maintenance of the content of retrofitting the repeater 114 to the meter 110 adjacent to the target meter (S144), and the target meter. Ends the processing for. Further, the maintenance control unit 156 may reconstruct the network after installing the repeater 114.

When the target meter is not a property in which the repeater cannot be installed (NO in S143), the maintenance control unit 156 determines whether or not there is a plan to install the repeater 114 in the apartment house in the future (S145).

If there is a plan to install the repeater 114 (YES in S145), the maintenance control unit 156 presents maintenance to wait until the repeater 114 is installed according to the plan (S146), and processes the target meter. To finish.

Maintenance when one or more repeaters 114 are installed in the apartment house in step S142 (YES in S142), or when there is no plan to install the repeater 114 in step S145 (NO in S145). The control unit 156 proceeds to "J" and performs the processing after "J" in FIG. 21.

As shown in FIG. 21, the maintenance control unit 156 that has advanced to “J” determines whether or not the network entry rate in the apartment house is less than a predetermined eighth threshold value (S150). The eighth threshold value is set to, for example, 90%, but can be arbitrarily set in consideration of the scale of the sensor network 100 and the like. Since the number of units in the apartment house is less than the specified number and the denominator of the network entry rate is small, the eighth threshold here is when the number of units in the apartment house is more than the specified number in consideration of the error of the network entry rate. It may be a value smaller than the third threshold value in the network entry rate of.

When the network entry rate is equal to or higher than the eighth threshold value (NO in S150), the maintenance control unit 156 determines whether or not the first average communication success rate of the meter 110 in the apartment building is less than the predetermined ninth threshold value. Is determined (S151). The ninth threshold value is set to, for example, 98%, but can be arbitrarily set depending on the installation position of the sensor node 112, the number of sensor nodes 112, and the like.

When the first average communication success rate is equal to or greater than the ninth threshold value (NO in S151), the maintenance control unit 156 has a predetermined number or more of the total number of sensor nodes 112 under the repeater 114 located upstream of the target sensor node. It is determined whether or not there is (S152). At this time, the repeater 114 may be inside the apartment house or outside the apartment house. Further, at this time, with respect to the sensor node 112 under the repeater 114, a part of the sensor node 112 may be located in a place other than the apartment house. The predetermined number is, for example, 30, but can be arbitrarily set in consideration of the allowable value of the number of sensor nodes 112 that can be assigned to one repeater 114.

When the total number of sensor nodes 112 under the repeater 114 located upstream of the target sensor node is equal to or greater than a predetermined number (YES in S152), the maintenance control unit 156 presents maintenance to reconstruct the network (YES in S152). S153), the process for the target meter is terminated. At this time, all the repeaters 114 and the sensor nodes 112 in the apartment house may be restarted, or some repeaters 114 or some sensor nodes 112 in the apartment house may be restarted. good. Further, at this time, the repeater 114 or the sensor node 112 other than the apartment house, which is involved in the repeater 114 or the sensor node 112 in the apartment house as well as in the apartment house, may be restarted.

When the total number of sensor nodes 112 under the repeater 114 located upstream of the target sensor node is less than a predetermined number (NO in S152), the maintenance control unit 156 presents maintenance as follow-up observation (S154). ), End the processing for the target meter.

In step S150, when the network entry rate is less than the eighth threshold value (YES in S150), or in step S151, the first average communication success rate is less than the ninth threshold value (YES in S151), the maintenance control unit. 156 determines whether or not the target sensor node is connected to the sensor node 112 outside the apartment building (S155).

If the target sensor node is not connected to the sensor node 112 outside the housing complex (NO in S155), the maintenance control unit 156 may or may not have entered the network even for one of the sensor nodes 112 in the housing complex. Is determined (S156).

If even one of the sensor nodes 112 in the apartment building has not entered the network (YES in S156), the maintenance control unit 156 presents maintenance to which the repeater 114 is retrofitted (S157), and the target meter is about the target meter. End the process.

When at least one or more of the sensor nodes 112 in the housing complex can enter the network (NO in S156), the maintenance control unit 156 may use the pipe shaft in which the target sensor node is located and other sensors in the housing complex. It is determined whether or not a radio wave has reached the pipe shaft on which the sensor node 112 is located (S158).

When the radio wave does not reach between the pipe shafts (YES in S158), the maintenance control unit 156 presents the maintenance of the content to be retrofitted with the repeater 114 (S159), and ends the process for the target meter.

When radio waves reach between the pipe shafts (NO in S158), the maintenance control unit 156 presents maintenance to replace the target sensor node or retrofit the repeater 114 (S160), and the target meter. Ends the processing for.

In step S155, when the target sensor node is connected to the sensor node 112 outside the apartment house (YES in S155), the maintenance control unit 156 proceeds to “K” and processes after “K” in FIG. 22. I do.

As shown in FIG. 22, in the maintenance control unit 156 advanced to “K”, the number of sensor nodes 112 under the repeater 114 in the out-of-building connection network to which the target sensor node belongs becomes the maximum allowable value. Whether or not it is determined (S170).

When the number of sensor nodes 112 under the repeater 114 in the out-of-building connection network to which the target sensor node belongs is the maximum allowable value (YES in S170), the maintenance control unit 156 reconstructs the network. The maintenance of the contents is presented (S171), and the processing for the target meter is terminated.

If the number of sensor nodes 112 under the repeater 114 in the out-of-building connection network to which the target sensor node belongs is less than the maximum allowable value (NO in S170), the maintenance control unit 156 will perform the maintenance control unit 156 in the apartment complex. It is determined whether or not a radio wave has reached between the pipe shaft where the target sensor node is located and the pipe shaft where the other sensor node 112 is located (S172).

When the radio wave does not reach between the pipe shafts (YES in S172), the maintenance control unit 156 presents the maintenance of the content to be retrofitted with the repeater 114 (S173), and ends the process for the target meter.

When radio waves reach between the pipe shafts (NO in S172), the maintenance control unit 156 presents maintenance to replace the target sensor node or retrofit the repeater 114 (S174), and the target meter. Ends the processing for.

According to the maintenance system 1 according to the third embodiment, it is possible to grasp the equipment requiring maintenance in the sensor network 100. Further, in the maintenance system 1 according to the second embodiment, it is possible to grasp the contents of maintenance.

(Maintenance system according to the fourth embodiment)
In the second embodiment and the third embodiment, various determinations are made for each of the plurality of meters 110 in the sensor network 100 as a target meter. However, in the sensor network 100, for example, 50 meters 110 (sensor nodes 112) are communicably arranged with respect to one repeater 114. If failure diagnosis and maintenance are performed individually for such a large number of meters 110, the processing becomes complicated and it may take time to complete.

Therefore, in the fourth embodiment, the meter 110 (sensor node 112) connected to the repeater 114 of 1 is divided into a plurality of groups, and the maintenance systems of the second embodiment and the third embodiment are applied to each group. Then perform failure diagnosis and maintenance.

In performing such grouping, an algorithm for identifying potential problem areas on the sensor network 100, such as joint points and bridges in graph theory, is applied to the topology estimated as shown in FIG. 5 (b). do. In the present embodiment, the joint point is the sensor node 112, and the bridge is the side (communication path) connecting the sensor nodes. Here, as an algorithm for specifying a joint point or a bridge, a Lowlink method using a depth-first search tree (DFStree) will be described.

FIG. 23 is a flowchart showing the flow of the Lowlink method. Here, first, the search order of each sensor node 112 of the sensor network 100 is arbitrarily determined, for example, from the root to the leaf direction, and a search number (ord) is assigned (S180). Here, the edge that does not pass when the edges of DFStree are searched in the order of search numbers is defined as the receding edge. Then, if the search number of the arbitrary sensor node 112 is larger than the search number of the sensor node 112 that can search through the receding side only once from the arbitrary sensor node 112, the search number of the arbitrary sensor node 112 recedes. It is updated to the search number (Low) of the sensor node 112 that can search through the side only once (S182). Further, when the search number of the arbitrary sensor node 112 is larger than the search number of the search destination sensor node 112 when the side of DFStree is searched in the order of the search number, the search number of the arbitrary sensor node 112 is the search destination. It is updated to the search number (Low) of the sensor node 112 (S184).

Thus, in the Lowlink method, the sensor node 112 that advances the DFStree side from any sensor node 112 in the order of search numbers (as many times as possible), and the receding side from any sensor node 112 from the leaf. The search numbers of the sensor nodes 112 that have advanced in the direction of the root (only once) are all equal at the minimum value (Low) of the search numbers.

FIG. 24 is an explanatory diagram for explaining the processing of the maintenance control unit 156. In the sensor network 100 shown in FIG. 24, the sensor node 112 is represented by a circle “◯”, and the number of hops is indicated by the numerical value in the circle. Here, it is assumed that the topology is estimated by the above-mentioned topology estimation system as shown in FIG. 24 (a).

It is assumed that the maintenance control unit 156 assigns a search number to each sensor node 112, for example, as shown in FIG. 24A. Here, it is assumed that the search is performed in ascending order of the number of hops. Is given. The numerical value next to the circle "○" in FIG. 24A indicates the updated search number, and the search number assigned first is indicated in parentheses next to it. Hereinafter, in order to identify each sensor node 112, the first assigned search number shown in parentheses in FIG. 24 is referred to as a “assigned search number”. In FIG. 24A, since the search number has not been updated yet, the updated search number and the assigned search number are equal to each other.

Next, the maintenance control unit 156 extracts the receding edge in the sensor network 100. Here, as shown by the broken arrow in FIG. 24 (b), the side from the sensor node 112 of the assigned search number “2” to the sensor node 112 of the assigned search number “0” is assigned. The side of the search number "1" assigned from the sensor node 112 of the search number "4" to the sensor node 112, and the sensor node of the search number "3" assigned from the sensor node 112 of the assigned search number "8". The side to 112 and the side from the sensor node 112 of the assigned search number "11" to the sensor node 112 of the search number "9" are the receding sides. Then, as shown in FIG. 24B, the maintenance control unit 156 updates the search number of the sensor node 112 of the assigned search number “2” to “0”, and the sensor of the assigned search number “4”. The search number of the node 112 is updated to "1", the search number of the sensor node 112 of the assigned search number "8" is updated to "3", and the search of the sensor node 112 of the assigned search number "11" is performed. Update the number to "9".

Subsequently, when the maintenance control unit 156 searches the side of DFStree from the root to the leaf direction, if the search number of the arbitrary sensor node 112 is larger than the search number of the search destination sensor node 112, the arbitrary sensor The search number of the node 112 is updated with the search number of the sensor node 112 to be searched. Here, as shown in FIG. 24 (c), the search number "10" of the sensor node 112 of the assigned search number "10" is the search of the sensor node 112 of the assigned search number "11" which is the search destination. Since it is larger than the number "9", the search number "10" of the sensor node 112 of the assigned search number "10" is the search number "9" of the sensor node 112 of the assigned search number "11" which is the search destination. Will be updated to. Similarly, since the search number "5" of the sensor node 112 of the assigned search number "5" is larger than the search number "3" of the sensor node 112 of the assigned search number "8" which is the search destination, it is assigned. The search number "5" of the sensor node 112 having the search number "5" is updated to the search number "3" of the sensor node 112 having the assigned search number "8" which is the search destination. Further, since the search number "3" of the sensor node 112 of the assigned search number "3" is larger than the search number "1" of the sensor node 112 of the assigned search number "4" which is the search destination, it is assigned. The search number "3" of the sensor node 112 of the search number "3" is updated to the search number "1" of the sensor node 112 of the assigned search number "4" which is the search destination. Further, since the search number "1" of the sensor node 112 of the assigned search number "1" is larger than the search number "0" of the sensor node 112 of the assigned search number "2" which is the search destination, it is assigned. The search number "1" of the sensor node 112 of the search number "1" is updated to the search number "0" of the sensor node 112 of the assigned search number "2" which is the search destination.

Here, when the two sensor nodes 112 forming the side in the direction of the leaves from the root have a relationship of the search number assigned to the upstream sensor node 112 <the updated search number of the downstream sensor node 112, the relationship thereof. The side is a specific route, and the upstream sensor node 112 is a specific route terminal. For example, as shown by the alternate long and short dash line in FIG. 24 (c), the search number "5" assigned to the sensor node 112 of the assigned search number "5" is the assigned search number which is the search destination. Since it is smaller than the updated search number "6" of the sensor node 112 of "6", the sensor node 112 of the search number "5" becomes a specific route terminal. Similarly, the sensor node 112 with the assigned search number “6” and the sensor node 112 with the assigned search number “10” are also specific route terminals. In this way, the search number is updated as shown in FIG. 24 (d).

FIG. 25 is an explanatory diagram for explaining other processes of the maintenance control unit 156. It is assumed that the maintenance control unit 156 assigns a search number to each sensor node 112, for example, as shown in FIG. 25A. Here, unlike FIG. 24A, a search number is assigned so that the number of hops is sequentially different for each search regardless of the number of hops, for example, as a counterclockwise search.

Next, the maintenance control unit 156 extracts the receding edge in the sensor network 100. Here, as shown by the broken arrow in FIG. 25 (b), the side from the sensor node 112 of the assigned search number “7” to the sensor node 112 of the assigned search number “2” is assigned. The side of the search number "0" assigned from the sensor node 112 of the search number "8" to the sensor node 112, and the sensor node of the search number "1" assigned from the sensor node 112 of the assigned search number "8". The side to 112 and the side from the sensor node 112 of the assigned search number "12" to the sensor node 112 of the search number "9" are the receding sides. Then, as shown in FIG. 25B, the maintenance control unit 156 updates the search number of the sensor node 112 of the assigned search number “7” to “2”, and the sensor of the assigned search number “8”. The search number of the node 112 is updated to "0", and the search number of the sensor node 112 of the assigned search number "12" is updated to "9".

Subsequently, when the maintenance control unit 156 searches the side of DFStree from the root to the leaf direction, if the search number of the arbitrary sensor node 112 is larger than the search number of the search destination sensor node 112, the arbitrary sensor The search number of the node 112 is updated with the search number of the sensor node 112 to be searched. Here, as shown in FIG. 25 (c), the search number “10” of the sensor node 112 with the assigned search number “10” is the search for the sensor node 112 with the assigned search number “12” which is the search destination. Since it is larger than the number "9", the search number "10" of the sensor node 112 of the assigned search number "10" is the search number "9" of the sensor node 112 of the assigned search number "12" which is the search destination. Will be updated to. Similarly, since the search number "2" of the sensor node 112 of the assigned search number "7" is larger than the search number "0" of the sensor node 112 of the assigned search number "8" which is the search destination, it is assigned. The search number "2" of the sensor node 112 of the search number "7" is updated to the search number "0" of the sensor node 112 of the assigned search number "8" which is the search destination. Further, since the search number "6" of the sensor node 112 of the assigned search number "6" is larger than the search number "0" of the sensor node 112 of the assigned search number "7" which is the search destination, it is assigned. The search number "6" of the sensor node 112 of the search number "6" is updated to the search number "0" of the sensor node 112 of the assigned search number "7" which is the search destination. Further, since the search number "3" of the sensor node 112 of the assigned search number "3" is larger than the search number "0" of the sensor node 112 of the assigned search number "6" which is the search destination, it is assigned. The search number "3" of the sensor node 112 of the search number "3" is updated to the search number "0" of the sensor node 112 of the assigned search number "6" which is the search destination. Further, since the search number "2" of the sensor node 112 of the assigned search number "2" is larger than the search number "0" of the sensor node 112 of the assigned search number "3" which is the search destination, it is assigned. The search number "2" of the sensor node 112 of the search number "2" is updated to the search number "0" of the sensor node 112 of the assigned search number "3" which is the search destination. Further, since the search number "1" of the sensor node 112 of the assigned search number "1" is larger than the search number "0" of the sensor node 112 of the assigned search number "2" which is the search destination, it is assigned. The search number "1" of the sensor node 112 of the search number "1" is updated to the search number "0" of the sensor node 112 of the assigned search number "2" which is the search destination.

Further, as shown by the alternate long and short dash line in FIG. 25 (c), the assigned search number "3" of the sensor node 112 of the assigned search number "3" is the assigned search number which is the search destination. Since it is smaller than the updated search number "4" of the sensor node 112 of "4", the sensor node 112 of the search number "3" becomes a specific route terminal. Similarly, the sensor node 112 with the assigned search number “4” and the sensor node 112 with the assigned search number “10” are also specific route terminals. In this way, the search number is updated as shown in FIG. 25 (d).

Here, the sensor node 112 is divided into a plurality of groups by using the search number updated by the Lowlink method. Specifically, the maintenance control unit 156 groups the sensor nodes 112 having the same search number after the update. Then, for example, as shown in FIGS. 24 (d) and 25 (d), a plurality of groups are formed.

However, in the present embodiment, if the group is too large, that is, if there are many sensor nodes 112 belonging to one group, the accuracy of specifying the device to be maintained in the group may be lowered. Therefore, in the present embodiment, although grouping is performed, the size of the group is limited and the number of groups is increased. Then, the number of groups in FIG. 24 (d) in which the search numbers are assigned in ascending order of the number of hops is larger than that in FIG. 25 (d) in which the search numbers are assigned so that the number of hops is sequentially different. Here, the specific accuracy can be improved by performing maintenance using the topology of FIG. 24 (d).

FIG. 26 is an explanatory diagram for explaining an image of grouping. The maintenance control unit 156 collects the topologies of FIG. 24D into groups having the same search number, and generates a simple topology as shown in FIG. 26. Here, seven groups with updated search numbers of "0", "1", "3", "6", "7", "9", and "12" are generated, respectively. The maintenance control unit 156 executes maintenance within the group for each group, and then performs maintenance between the groups.

FIG. 27 is an explanatory diagram for explaining maintenance in the group. In FIG. 27, the group of the search number “9” is taken as an example. Here, it is assumed that the communication success rate of the sensor node 112 of the assigned search number "9" and the sensor node 112 of the assigned search number "11" is 100%. On the other hand, it is assumed that the communication success rate of the sensor node 112 with the assigned search number "10" is 95%. In this case, successful communication between the sensor node 112 with the assigned search number "9", the sensor node 112 with the assigned search number "11", and the sensor node 112 with the assigned search number "10" in the group. The rate difference is equal to or greater than the first difference threshold (for example, 2%). The first difference threshold can be set arbitrarily.

In the example of FIG. 27, each of the sensor nodes 112 in the group can communicate with two or more sensor nodes 112, and since there is a communication circuit, the communication success rates should be approximately equal. However, the communication success rate of the sensor node 112 with the assigned search number "10" is 95%, and the communication success rate difference from the communication success rate 100% of the other sensor nodes 112 of the same group is the first difference. It is above the threshold. In this case, the maintenance control unit 156 has a problem with the sensor node 112 of the assigned search number “10” surrounded by a thick line in FIG. 27 (for example, the communication setting itself is incorrect), or the sensor node 112 is assigned. The communication route between the sensor node 112 with the assigned search number "10" and the sensor node 112 with the assigned search number "9", or the sensor node 112 with the assigned search number "10" and the assigned search. It is presumed that the connection environment of the communication route with the sensor node 112 of the number "11" has deteriorated, and it becomes possible to make it a target for maintenance.

28 and 29 are explanatory views for explaining maintenance between groups. In FIG. 28, a group having a search number “1” and a group having a search number “3” are taken as an example, and in FIG. 29, a group having a search number “9” and a group having a search number “12” are taken as an example. There is.

In the example of FIG. 28, it is assumed that the average value of the communication success rate of the group with the search number "1" is 100%, and the average value of the communication success rate of the group with the search number "3" is 95%. In this case, the communication success rate difference between the group with the search number "1" and the group with the search number "3" is equal to or larger than the second difference threshold value (for example, 2%).

Since there is a possibility that a plurality of sensor nodes 112 communicate with each other across the groups, the communication success rates should be approximately equal. However, the average value of the communication success rate of the group with the search number "3" located downstream is 95%, and the average value of the communication success rate of the group with the search number "1" located upstream is 100%. The communication success rate difference is equal to or greater than the second difference threshold. In this case, the maintenance control unit 156 presumes that there is a problem in the connection between the group with the search number "1" and the group with the search number "3" (for example, the communication setting itself is incorrect), and is subject to maintenance. It becomes possible to.

Further, in the example of FIG. 29, it is assumed that the average value of the communication success rate of the group with the search number "9" is 100%, and the average value of the communication success rate of the group with the search number "12" is 95%. In this case, the communication success rate difference between the group with the search number "9" and the group with the search number "12" is equal to or larger than the second difference threshold value (for example, 2%). The second difference threshold can be set arbitrarily.

As described above, since there is a possibility that a plurality of sensor nodes 112 are communicating with each other across the groups, the communication success rates should be approximately equal. However, the average communication success rate of the group with the search number "12" located downstream is 95%, and the average communication success rate of the group with the search number "9" located upstream is 100%. The communication success rate difference is equal to or greater than the second difference threshold. Further, the sensor node 112 with the assigned search number "10" is a specific route terminal. In this case, the maintenance control unit 156 connects the group of the search number "9" and the group of the search number "12", specifically, the sensor node 112 of the assigned search number "10" and the assigned search. It is possible to presume that there is a problem in the connection with the sensor node 112 of the number "12" (for example, the communication setting itself is incorrect).

Here, the reason why the communication success rate is averaged is that the communication success rate should be the same within the group, so that the communication success rate is specified by averaging to improve the accuracy. However, as described with reference to FIG. 27, when the sensor node 112 in question exists in the group, the sensor node 112 may be excluded and the communication success rate may be averaged. Furthermore, if there is a problematic sensor node 112 in the group, if the sensor node 112 is a specific route terminal or a long-distance propagation terminal, it is not excluded, and if there is a circuit, it is excluded and the communication success rate is averaged. It may be changed.

With such a configuration, it becomes possible to appropriately grasp the equipment requiring maintenance in the sensor network 100.

Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such an embodiment. It is clear that a person skilled in the art can come up with various modifications or modifications within the scope of the claims, which naturally belong to the technical scope of the present invention. Understood.

For example, in the maintenance system 1 according to each of the above embodiments, the topology estimation device 130 and the maintenance device 150 are provided separately from the center device 116, and the topology control unit 136 of the topology estimation device 130 estimates the topology of the maintenance device 150. An example in which the maintenance control unit 156 executes maintenance has been described. However, the topology control unit 136 and the maintenance control unit 156 may be provided in the center device 116 to estimate the topology or perform maintenance in the center device 116, and the topology estimation device 130 and the maintenance device 150 may not be provided.

Further, a program that causes the computer to function as the topology estimation device 130, the maintenance device 150, the meter 110, the sensor node 112, or the center device 116, and a computer-readable flexible disk or magneto-optical disk that records the program. , ROM, CD, DVD, BD and other storage media are also provided. Here, the program refers to a data processing means described in any language or description method.

It should be noted that each process shown in the present specification does not necessarily have to be processed in chronological order in the order described in the flowchart, and may include parallel or subroutine processing.

100 Sensor network 110 Meter 112 Sensor node 114 Repeater 116 Center device 118 Base station 126 Center control unit 130 Topology estimation device 136 Topology control unit 150 Maintenance device 156 Maintenance control unit

Claims (6)

Sensor nodes associated with each of the multiple meters and
A repeater connected to the sensor node and collecting information on the meter through the sensor node.
A center control unit that collects meter information through a multi-hop type sensor network through the sensor node and the repeater.
A topology control unit that estimates the topology of the sensor network, and
Equipped with
The topology control unit
It is determined that the sensor node with the number of N + 1 (N ≧ 0) hops satisfying the first communication distance condition and the sensor node with the number of N hops are connected.
A topology estimation system that determines that sensor nodes that have the same number of hops and satisfy the second communication distance condition are connected to each other. The topology control unit
A sensor node having an N hop number whose connection date connected to the sensor network is later than the connection date of the sensor node having the N + 1 hop number is excluded from the target for determining that the sensor node having the N + 1 hop number is connected. The topology estimation system according to claim 1. The topology control unit
When there is no sensor node having N + 1 hops and a sensor node having N hops satisfying the first communication distance condition, the connection date connected to the sensor network is a predetermined number of days before the connection date of the sensor node having N + 1 hops. It is determined that the sensor node having the shortest relative distance from the sensor node having the N + 1 hop number and the sensor node having the N + 1 hop number are connected to each other among the sensor nodes having the number of N hops. The topology estimation system according to claim 1 or 2. The topology control unit
There is no sensor node with N + 1 hops and no sensor node with N hops that satisfies the first communication distance condition, and the connection date connected to the sensor network is from the connection date of the sensor node with N + 1 hops to a predetermined number of days before. If there is no sensor node with N hops, it is determined that the sensor node with N + 1 hops, the sensor node with the shortest relative distance, and the sensor node with N + 1 hops are connected. The topology estimation system according to any one of claims 1 to 3. The topology control unit
The topology estimation system according to any one of claims 1 to 4, wherein it is determined that the node having the number of N + M hops (M ≧ 2) and the node having the number of N hops are not connected. A multi-hop type sensor network through a sensor node associated with each of a plurality of meters, a repeater connected to the sensor node and collecting information on the meter through the sensor node, and the sensor node and the repeater. It is a topology estimation method for estimating the topology of a sensor network having a center control unit that collects information on the meter.
It is determined that the sensor node with the number of N + 1 (N ≧ 0) hops satisfying the first communication distance condition and the sensor node with the number of N hops are connected.
A topology estimation method that determines that sensor nodes that have the same number of hops and satisfy the second communication distance condition are connected to each other.

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