How to design a sensor network system

Abstract

To construct a realistic sensor network system.SOLUTION: For each predetermined section of ground, any of use area identifiers showing use areas classified into a plurality of types is associated. The use area identifiers and propagation distances of radio waves radiated from a sensor are associated. A design method for a sensor network system includes: on the basis of a position of a first meter, identifying a use area identifier of a use area to which a first sensor node corresponding to the first meter belongs; on the basis of the identified use area identifier, setting a propagation distance of a radio wave radiated from the first sensor node; and, on the basis of the propagation distance, identifying a group to which the sensor node belongs.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a method for designing a sensor network system that collects information from a plurality of meters. [Background technology]

[0002] Gas and electric power companies install gas and electric power meters at points of demand in order to accumulate the amount of gas and electric power consumed by consumers. In recent years, the installation of smart meters that have communication functions and can communicate data bidirectionally with gas and electric power companies and automatically read the amount of gas and electric power used remotely has been promoted. Such smart meters can also be used as information sources to improve the safety and utilization efficiency of infrastructure networks such as gas and electric power.

[0003] In addition, various means have been proposed to realize data communication between the above-mentioned smart meters and gas and electric power companies. For example, a mesh network may be formed by equipping the smart meters with short-range wireless devices, a star network may be formed using a mobile phone network such as LTE (Long Term Evolution), or a star network may be formed using power line communication.

[0004] As an application of a mesh network, a technology is known in which a backbone network and ad-hoc communication by wireless LAN are provided in parallel, and smart meters are operated stably by switching to the ad-hoc communication in the event of a failure in the backbone network (for example, Patent Document 1). Technology related to network routing has also been disclosed (for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2012-065422 A [Patent Document 2] JP 2012-105258 A Summary of the Invention [Problem to be solved by the invention]

[0006] In a sensor network system, a sensor node is associated with each of a number of meters, and the sensor nodes establish communication with a center device via a repeater. The repeater acquires meter information from the sensor nodes and transmits it to the center device.

[0007] In a sensor network system, wireless communication is performed between sensor nodes. The location of a sensor node is limited to the meter corresponding to the sensor node or its vicinity, so the propagation distance of radio waves emitted from the sensor node varies depending on the installation environment of the sensor node. For this reason, if the propagation distance were set uniformly regardless of the sensor node, the set propagation distance may differ from the actual propagation distance, which may cause unstable communication. This may result in the sensor network system that is constructed being different from a realistic sensor network system.

[0008] In view of the above problems, an object of the present invention is to provide a method for designing a sensor network system that is capable of constructing a practical sensor network system. [Means for solving the problem]

[0009] In order to solve the above problems, the sensor network system design method of the present invention is a design method for a sensor network system comprising a plurality of sensor nodes each associated with a plurality of meters, and a center device that collects meter information through the sensor nodes, in which the plurality of sensor nodes transmit and receive meter information through wireless communication between the sensor nodes, in which each of a predetermined section of land is associated with one of a plurality of zoning identifiers indicating zoning zones classified into multiple types, and the zoning identifiers are associated with a propagation distance of radio waves emitted from the sensor nodes, and the zoning identifier of the zoning zone to which the first sensor node corresponding to the first meter belongs is identified based on the position of the first meter, the propagation distance of the radio waves emitted from the first sensor node is set based on the identified zoning identifier, and the group to which the sensor node belongs is identified based on the propagation distance.

[0010] In addition, for each specified section of land, a zoning identifier is associated with the land use identifier, and a building coverage ratio related to the zoning identifier is associated with the land use identifier. A combination of the zoning identifier and the building coverage ratio is associated with a propagation distance of radio waves emitted from the sensor node, and the propagation distance of the radio waves emitted from the first sensor node may be set based on the zoning identifier and the building coverage ratio associated with the position of the first meter.

[0011] In addition, for each specified section of land, a zoning identifier is associated with the land use identifier, and a floor area ratio related to the zoning identifier is associated with the land use identifier. The combination of the zoning identifier and the floor area ratio is associated with the propagation distance of the radio waves emitted from the sensor node, and the propagation distance of the radio waves emitted from the first sensor node may be set based on the zoning identifier and the floor area ratio associated with the position of the first meter.

[0012] In addition, a first use zone identifier of the use zone to which the first sensor node belongs may be identified based on the position of the first meter, and a second use zone identifier of the use zone to which the second sensor node corresponding to the second meter belongs may be identified based on the position of the second meter, and the propagation distance of the radio waves emitted from the first sensor node may be set based on the identified first use zone identifier and second use zone identifier.

[0013] In addition, a reference node, which is a sensor node that is a candidate for installing a relay that relays between the sensor node and a center device, may be specified, and a group may be generated with the reference node and a predetermined number or less of sensor nodes whose distance from the reference node satisfies a predetermined distance condition and which belong to the same zoning zone as the reference node, and the relay may be associated with the reference node of the generated group. Effect of the Invention

[0014] According to the present invention, it is possible to construct a practical sensor network system. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is an explanatory diagram showing a schematic configuration of a sensor network system. [Diagram 2] FIG. 2 is a functional block diagram showing a schematic configuration of a center device. [Diagram 3] FIG. 2 is a diagram showing an example of a land use district database. [Figure 4] FIG. 11 is a diagram illustrating an example of a propagation distance table. [Diagram 5] 11 is a flowchart illustrating a flow of processing executed by a network design unit. [Figure 6] FIG. 2 is an explanatory diagram for explaining a sensor network system to be constructed. [Figure 7] 11 is a flowchart illustrating a flow of a propagation distance setting process. [Figure 8] FIG. 11 is a diagram illustrating an example of a propagation distance table in the second embodiment. [Figure 9] 10 is a flowchart illustrating a flow of a propagation distance setting process in the second embodiment. [Figure 10] FIG. 13 is a diagram illustrating an example of a propagation distance table in the third embodiment. [Figure 11] 13 is a flowchart illustrating a flow of a propagation distance setting process according to the third embodiment. [Figure 12] 13 is a flowchart illustrating a flow of a process executed by a network design unit according to the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific values ​​shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are given the same reference numerals to avoid repeated explanations, and elements not directly related to the present invention are not shown.

[0017] (Sensor network system 100) Fig. 1 is an explanatory diagram showing a schematic configuration of a sensor network system 100. As shown in Fig. 1, the sensor network system 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.

[0018] The meter 110 is, for example, a smart meter, and is installed at each consumer, that is, at each dwelling unit of an individual house or an apartment building. The meter 110 is a device that automatically reads at least the amount of gas or electricity used when gas is supplied from a gas company to a consumer, or electricity is supplied from an electricity company to a consumer. In this embodiment, for convenience of explanation, a gas meter 110 provided by a gas company is illustrated, but it goes without saying that the meter 110 can also be applied to electricity (electricity).

[0019] The sensor nodes 112 are installed in one-to-one correspondence with each meter 110. For example, the sensor nodes 112 may be attached to the outside of the meter 110 or may be built into the meter 110. The location of the sensor nodes 112 is limited to the vicinity of the meter 110 (the vicinity of the consumer). The sensor nodes 112 can acquire information (data) used by the meter 110 from the associated meter 110. The sensor nodes 112 are capable of wireless communication between each other, and transmit and receive at least information used by the meter 110. Hereinafter, the information used by the meter 110 may be referred to as information of the meter 110. The information of the meter 110 may include any information used by the meter 110, such as the amount of gas used and information for identifying the meter 110.

[0020] The repeater 114 functions as a gateway device that connects different networks together, and is installed in association with one of the multiple sensor nodes 112. The repeater 114 establishes wired communication with the sensor node 112 associated with it, and also establishes communication with the center device 116. The repeater 114 then establishes wireless communication with one or more surrounding sensor nodes 112 through the associated sensor node 112.

[0021] However, since communication between sensor nodes 112 is realized by short-distance wireless communication, it is not necessarily the case that all sensor nodes 112 can directly establish wireless communication with the sensor nodes 112 associated with the repeaters 114. In this case, the sensor node 112 is connected to the repeater 114 by hopping (via) one or more other sensor nodes 112 that can wirelessly communicate. In other words, the sensor nodes 112 form a multi-hop network. In this way, the repeater 114 can collect information of each sensor node 112 through the associated sensor node 112 and other surrounding sensor nodes 112 and transmit it to the center device 116, and can also transmit information of the center device 116 to the surrounding sensor nodes 112. At this time, the transmitted information also includes an identifier that identifies the repeater 114 and the base station 118 through which the information was transmitted, so the center device 116 can identify the source and route of the information.

[0022] The center device 116 is composed of a computer or the like, and is a device that belongs to the administrator of the sensor network system 100, such as a gas supplier or an electric power supplier. The center device 116 establishes communication with one or more repeaters 114, and collects or transmits information.

[0023] The base station 118 can establish communication with both the repeater 114 and the center device 116, and relays communication between the repeater 114 and the center device 116.

[0024] Here, the 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 use existing paid communication networks, such as a mobile phone network or a PHS (Personal Handyphone System) network, for example, a 5G (Generation) communication network or a 4G communication network, in which communication fees are charged according to the amount of communication. Such paid communication networks are managed by, for example, a communication carrier, which is different from a gas company or an electric power company.

[0025] The sensor nodes 112 establish wireless communication with each other through a wireless system for smart meters (U-Bus Air) that uses, for example, the 920 MHz band. It is assumed that such wireless communication between the sensor nodes 112 is free, but it does not matter whether it is free or paid, as long as the communication cost is at least lower than that of the communication between the repeater 114 and the center device 116. Through such wireless communication, the repeater 114 is connected to the center device 116 through a paid communication network, and is connected to each sensor node 112 through the wireless system for smart meters.

[0026] In the sensor network system 100, a meter 110 and a sensor node 112 are arranged for each consumer. As described above, a repeater 114 may be arranged for each meter 110 and sensor node 112. The center device 116 collects information from 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 are arranged in any location where a consumer exists.

[0027] (Design method of the sensor network system 100 according to the first embodiment) As described above, by constructing a sensor network system 100 that transmits information between the sensor node 112 and the center device 116, it becomes possible for the gas company's meter readers to collect meter reading information (automatic meter reading) without having to directly read the meters 110, thereby improving the efficiency of operations.

[0028] In the sensor network system 100, the meters 110 are periodically replaced to eliminate problems caused by deterioration over time. The meters 110 have a set certification validity period, for example, 10 years, and must be replaced when the certification validity period expires. However, rather than replacing all the meters 110 at once, for example, 1 / 10 of the total amount is replaced every year, so that replacement of the entire amount is completed at least after 10 years.

[0029] Hereinafter, the expiration of the certification validity period may be referred to as a "full inspection", a meter 110 whose certification validity period will expire may be referred to as a "full inspection meter", and a sensor node 112 corresponding to a meter 110 whose certification validity period will expire may be referred to as a "full inspection node".

[0030] Here, it is preferable that the sensor node 112 is installed in association with the meter 110, and the location is limited to the vicinity of the meter 110 (the vicinity of the consumer), and the communication environment between the sensor nodes 112 is also limited depending on the arrangement conditions of the meter 110. The sensor network system 100 is designed to associate one repeater 114 with a predetermined number (for example, 30) of sensor nodes 112, but if the repeaters 114 are uniformly associated with each other, communication may become unstable. Therefore, it is preferable to build the sensor network system 100 taking into consideration the installation conditions of the meter 110, and it has been difficult to build an efficient sensor network system 100. In addition, since the meter 110 is replaced at the expiration date of the meter 110 (at the expiration of the valid period of the certification), when the meter 110 breaks down, or when the number of the meter 110 is changed, it is necessary to design the sensor network system 100 taking into consideration the time when each sensor node 112 can be effectively used.

[0031] As described above, in the sensor network system 100, wireless communication is performed between the sensor nodes 112. Since the location of the sensor node 112 is limited to the meter 110 corresponding to the sensor node 112 or its vicinity, the propagation distance of the radio waves emitted from the sensor node 112 varies depending on the installation environment of the sensor node 112. For this reason, if the propagation distance is set uniformly regardless of the sensor node 112, the set propagation distance may differ from the actual propagation distance, which may cause unstable communication. If this happens, there is a risk that the constructed sensor network system 100 will differ from a realistic sensor network system 100.

[0032] Therefore, in this embodiment, an efficient sensor network system 100 is constructed without installing an unnecessary large number of repeaters 114. In this case, in this embodiment, a realistic sensor network system 100 is constructed by appropriately setting the propagation distance for each sensor node 112. In this embodiment, for example, the center device 116 executes a process for designing the sensor network system 100, and the sensor network system 100 is actually constructed according to the result of the process.

[0033] (Configuration of the Center Apparatus 116) 2 is a functional block diagram showing a schematic configuration of the center device 116. The center device 116 includes a center communication unit 160, a center storage unit 162, and a center control unit 164.

[0034] The center communication unit 160 establishes communication with the repeater 114 through the base station 118 .

[0035] The center storage unit 162 is composed of a RAM, a flash memory, a HDD, etc. The center storage unit 162 holds various information such as conduit mapping used by the center device 116. In addition, the center storage unit 162 stores a use area database 170 and a propagation distance table 172.

[0036] 3 is a diagram showing an example of the use zoning database 170. Here, for each predetermined section of land, one of use zoning identifiers indicating use zoning classified into a plurality of types is associated with the land. Note that land means land that is not permanently covered by water such as the sea or a river. Therefore, for example, the sea or a river may not be assigned a use zoning identifier.

[0037] A use zone is a classification of the use of land in a specified area (i.e., a specified region) into multiple uses. More specifically, use zones are classified into 13 types: Type 1 low-rise residential zone, Type 2 low-rise residential zone, Type 1 medium- to high-rise residential zone, Type 2 medium- to high-rise residential zone, Type 1 residential zone, Type 2 residential zone, semi-residential zone, rural residential zone, neighborhood commercial zone, symptom zone, semi-industrial zone, industrial zone, and industrial zone.

[0038] The use zoning identifier is, for example, the name of the use zoning, such as a first-class low-rise residential exclusive zone. A use zoning classification code for identifying the use zoning may be assigned to each use zoning. In that case, the use zoning classification code may be used as the use zoning identifier. In other words, the use zoning identifier may be any information that can identify the use zoning corresponding to a specific section.

[0039] A predetermined section indicates an area surrounded by a predetermined plane polygon on a map, for example, as shown in Fig. 3. The coordinates of each vertex of a plane polygon are specified, and the plane polygon can be specified by connecting the coordinates of each vertex. The land use zoning database includes polygon data in which land on a map is divided by a plurality of plane polygons, as shown in Fig. 3. The polygon data is, for example, published by the Geospatial Information Authority of Japan.

[0040] In the polygon data published by the Geospatial Information Authority of Japan, the interior of each plane polygon is color-coded. However, in Fig. 3, for ease of explanation, the plane polygons are classified by the hatching pattern (direction of lines and spacing between lines) instead of color coding.

[0041] The hatching pattern or color within a planar polygon corresponds to the use zoning identifier corresponding to the planar polygon. In other words, in the use zoning database, a specific section on the map (a planar polygon of the polygon data) and a use zoning identifier are associated with each specific section.

[0042] Fig. 4 is a diagram showing an example of the propagation distance table 172. Note that the specific numerical values ​​shown in Fig. 4 are merely examples, and the numerical values ​​are not limited to those shown as examples, and may be set to any numerical values.

[0043] 4, in the propagation distance table, the use area identifier is associated with the propagation distance of the radio wave emitted from the sensor node 112 for each use area identifier. In other words, in the propagation distance table, the propagation distance of the radio wave emitted from the sensor node 112 installed in the use area indicated by the specified use area identifier is specified for each use area identifier.

[0044] For example, a sensor node 112 installed in a predetermined use area is set as a reference sensor node, and the connection probability of wireless communication between the reference sensor node and other sensor nodes 112 is derived by actual measurement or simulation. This derivation of the connection probability is repeated multiple times by changing the distance between the reference node and other sensor nodes 112. The minimum value of the distances between the reference sensor node and other sensor nodes 112 at which the connection probability is equal to or greater than a predetermined probability can be regarded as the propagation distance of the radio waves emitted from the reference sensor node.

[0045] The predetermined probability is set to, for example, 50%, but is not limited to this example and may be set to any value that allows proper connection of wireless communication between the reference sensor node and other sensor nodes 112. In short, with the propagation distance determined in this way, it can be expected that communication connection is possible with a probability of, for example, 50% or more. The propagation distance of the reference sensor node determined in this way is associated with the use zone identifier of the use zone to which the reference sensor node belongs, and a propagation distance table is created.

[0046] The propagation distance table may be created using machine learning. For example, the center device 116 performs machine learning using the use area classification code of the use area to which the first sensor node 112 corresponding to the first meter 110 belongs, the use area classification code of the use area to which the second sensor node 112 corresponding to the second meter 110 belongs, the distance between the first meter 110 and the second meter 110, and the presence or absence of a communication connection between the first sensor node 112 and the second sensor node 112 as teacher data to generate a machine learning model. When the use area classification code of the first sensor node 112 to be evaluated, the use area classification code of the second sensor node 112 to be evaluated, and the distance between the first meter 110 to be evaluated and the second meter 110 to be evaluated are input, the machine learning model outputs a connection probability of a communication connection between the first sensor node 112 to be evaluated and the second sensor node 112 to be evaluated.

[0047] The center device 116 inputs the distances to the machine learning model by shifting them little by little, and derives the connection probability for each distance. The center device 116 sets the threshold of the connection probability to 50%, and sets the distance when the connection probability changes from less than 50% to 50% or more as the propagation distance of the first sensor node 112 to be evaluated. The center device 116 may create a propagation distance table by associating the propagation distance of the first sensor node 112 to be evaluated with the use zone identifier of the use zone to which the first sensor node 112 to be evaluated belongs.

[0048] Returning to Fig. 2, the center control unit 164 is composed of a processor and a memory that stores a program. The processor executes the program, and the center control unit 164 functions as a network design unit 180. The network design unit 180 executes a process of designing the sensor network system 100. The process executed by the network design unit 180 will be described below.

[0049] Fig. 5 is a flowchart explaining the flow of processing executed by the network design unit 180. Fig. 6 is an explanatory diagram for explaining the sensor network system 100 to be constructed. In Fig. 6, a full inspection meter (or a full inspection node associated therewith) is shown in white, and a meter 110 whose valid inspection period has not yet expired is shown in solid black.

[0050] First, the network design unit 180 executes a propagation distance setting process (S100) for setting a propagation distance for each of a plurality of inspection-completed nodes to be designed in the sensor network system 100. The propagation distance setting process will be described in detail later. When the propagation distance setting process is executed, the propagation distance of the radio wave of the inspection-completed node is set for each inspection-completed node.

[0051] After setting the propagation distance, the network design unit 180 arbitrarily selects one of the multiple inspection-qualified nodes to be designed in the sensor network system 100 and sets it as the reference node (S200). Here, the inspection-qualified node indicated by "A" in FIG. 6(a) is set as the reference node.

[0052] Next, the network design unit 180 determines whether or not there are a predetermined number of sensor nodes 112 whose distance from the reference node satisfies a predetermined distance condition, for all sensor nodes 112 to be designed in the sensor network system 100 (S202).

[0053] Here, the predetermined distance condition is that the sensor nodes 112 are within a distance that is deemed to be adjacent to each other. More specifically, the predetermined distance condition is whether a sensor node 112 is located within a propagation distance at a reference node determined by a usage area to which the reference node belongs from the reference node, or whether another sensor node 112 is located within a propagation distance at the determined sensor node 112 determined by a usage area to which the determined sensor node 112 belongs from the sensor node 112 determined to be located within the propagation distance.

[0054] For example, the network design unit 180 extracts sensor nodes 112 whose distance from a reference node is within the propagation distance at the reference node determined by the use zone to which the reference node belongs. Furthermore, the network design unit 180 extracts sensor nodes 112 whose distance from the extracted sensor node 112 is within the propagation distance at the extracted sensor node 112 determined by the use zone to which the extracted sensor node 112 belongs. The network design unit 180 repeats such processing until there are no sensor nodes 112 whose distance from the sensor node 112 on the reference side of the distance is within the propagation distance at the sensor node 112 on the reference side of the distance, or until the number of extracted sensor nodes 112 reaches a predetermined number.

[0055] Therefore, among the sensor nodes 112 that are multiple hops away from the reference node, if the distance from the sensor node 112 on the reference side of the distance is within the propagation distance of the sensor node 112 on the reference side of the distance, all such sensor nodes 112 satisfy the distance condition.

[0056] In the example of Fig. 6(a), three sensor nodes 112 indicated by "B" are targeted based on the propagation distance of the reference node "A" for the reference node "A". Here, the sensor nodes 112 that satisfy a predetermined distance condition are shown connected by dashed lines.

[0057] The reason why the distance condition is judged not only for the fully inspected nodes but for all the sensor nodes 112 including the sensor nodes 112 that have not yet reached the valid inspection period is as follows: In other words, since all the meters 110 should be associated with sensor nodes 112 in 10 years, a predetermined number of nearby sensor nodes 112 that satisfy a predetermined distance condition are secured at the present time so that the group will be complete at that time. Also, it goes without saying that the fully inspected nodes may be included in the sensor nodes 112 that satisfy the predetermined distance condition.

[0058] The predetermined number is set to a number smaller than the maximum allowable number of sensor nodes 112 to which the repeater 114 can be connected. By making the predetermined number smaller than the maximum allowable number in this way, when a new meter 110 is added in the next fiscal year or later and the sensor node 112 of the meter 110 is adjacent to the reference node, communication between the reference node and the added sensor node 112 can be permitted. The predetermined number is an appropriate value assuming that each repeater 114 can permit communication with the maximum allowable number or less of sensor nodes 112 after a predetermined number of years (e.g., 10 years). For example, the predetermined number is set to "30" for the maximum allowable number of "50". However, in FIG. 6, the predetermined number is described as "3" for the convenience of explanation.

[0059] In this way, when the predetermined number of sensor nodes 112 satisfying the predetermined distance condition is reached during extraction (YES in S202), the network design unit 180 generates a group with the reference node and the extracted sensor nodes 112 regardless of whether there are any more sensor nodes 112 satisfying the predetermined distance condition (S204). For example, in the example of Fig. 6(a), a group "C" is generated that includes three sensor nodes 112 "B" with "A" as the reference node. At this time, a group ID that identifies the generated group is assigned to the sensor nodes 112 in group "C".

[0060] The sensor nodes 112 included in the group thus generated are established as part of the sensor network system 100. Therefore, the sensor nodes 112 included in the group thus generated are excluded from the design method of the sensor network system 100 for the next year and thereafter (S206). In this way, the sensor nodes 112 excluded from the target are not subject to the reference node setting process S200 or the test-satisfied node determination process S214 described below as a test-satisfied node, and are not subject to the distance condition determination process S202 as the sensor node 112.

[0061] In this way, in Fig. 6(a), the grouped "A" full inspection node and "B" sensor node 112 are excluded from the candidates for the reference node. Therefore, in the next reference node setting process S200, as shown in Fig. 6(b), the full inspection node excluding the "A" full inspection node, for example, the full inspection node shown by "D", is set as the reference node. Then, in the group generation process S204, the three sensor nodes 112 shown by "E" are targeted for the reference node "D" in Fig. 6(b), and a group "F" containing the three "E" sensor nodes 112 with "D" as the reference node is generated. In this way, new groups are generated sequentially.

[0062] If the number of sensor nodes 112 that satisfy the predetermined distance condition is less than the predetermined number (NO in S202), the network design unit 180 determines whether the sensor node group consisting of the reference node and the extracted sensor nodes 112 that are less than the predetermined number satisfies the predetermined distance condition with other groups that have already been generated (S208). If the sensor node group does not satisfy the predetermined distance condition with other groups (NO in S208), a group is generated with the sensor node group, i.e., the reference node and the extracted sensor nodes 112 that are less than the predetermined number (S210).

[0063] For example, if a sensor node group including two "H" sensor nodes 112 with "G" as the reference node in Fig. 6(c) does not satisfy a predetermined distance condition with other groups "C" and "F", a group "I" is generated including two "H" sensor nodes 112 with "G" as the reference node. At this time, a group ID that identifies the generated group is assigned to the sensor nodes 112 in group "I".

[0064] Since the sensor nodes in group "I" do not satisfy the predetermined distance condition with other groups, it is unlikely that communication will be established with the sensor nodes 112 in other groups not only this year, but also in the next year and thereafter. Here, even if the number of such sensor nodes is less than the predetermined number, by treating them as independent groups, it is possible to establish communication within group "I", for example, and to establish communication with many sensor nodes 112.

[0065] Then, in the same manner as when a group is generated in the group generation process S204, the sensor nodes 112 included in the generated group are excluded from the targets of the design method for the sensor network system 100 from the next year onwards (S206).

[0066] Also, if the sensor node group satisfies a predetermined distance condition with other groups (YES in S208), the reference node setting is cancelled and the sensor node becomes a simple test-satisfied node (S212). For example, if a sensor node group including the sensor node 112 of "K" with "J" as the reference node in FIG. 6(d) satisfies a predetermined distance condition with other groups "C" and "F", the reference node setting of "J" is cancelled. Here, the sensor node group is not grouped because it satisfies a predetermined distance condition with other groups, so it is expected that communication will be established with the sensor node 112 of the other groups, and even if communication is not established this year, there is a high possibility that communication will be established next year or later. In this way, by not setting an unnecessarily large number of reference nodes, an efficient sensor network system 100 can be constructed while suppressing the absolute number of repeaters 114.

[0067] In addition, simply canceling the reference node setting may result in the same node being set as the reference node again in the reference node setting process S200. Therefore, in order to prevent unnecessary processing from being repeated, all extracted nodes should be excluded from the candidates for the reference node. In addition, if the number of sensor nodes 112 that satisfy a predetermined distance condition is less than a predetermined number (NO in S202) and the sensor node group satisfies a predetermined distance condition with other groups (YES in S208), each sensor node 112 of the sensor node group will not be included in other groups in the following processing. Therefore, similar to the case where groups are generated in the group generation process S204, the sensor nodes 112 included in the extracted sensor node group are excluded from the design method of the sensor network system 100 for the next year and thereafter (S206).

[0068] In this way, the inspection nodes and sensor nodes 112 that have not been grouped may become eligible for grouping if, for example, a new building is constructed in the next fiscal year or later, and the number of sensor nodes 112 that satisfy the specified distance condition increases, and the number of sensor nodes 112 exceeds the specified number.

[0069] After excluding the sensor node 112 from the target (S206), the network design unit 180 judges whether there is a non-selected non-inspection node (S214). If there is a non-selected non-inspection node (YES in S214), one sensor node 112 is arbitrarily selected from the non-inspection nodes, and the process from the reference node setting process S200 is repeated.

[0070] On the other hand, if there are no unselected nodes (NO in S214), the network design unit 180 associates the repeater 114 with the reference node of the group generated in the group generation process S204 and the group generation process S210 (S216), and ends the series of processes.

[0071] In the sensor network system 100, wireless communication is performed between the multiple sensor nodes 112 belonging to the group thus generated, and this group corresponds to one network. That is, the group generation process S204 and the group generation process S210 identify the group to which the sensor node 112 belongs, in other words, the group indicating the group of sensor nodes that are capable of wireless communication between the sensor nodes 112.

[0072] 7 is a flowchart explaining the flow of the propagation distance setting process (S100). When the propagation distance setting process is started, the network design unit 180 arbitrarily selects one sensor node 112 from among the multiple sensor nodes 112 to be designed in the sensor network system 100, and specifies the meter 110 corresponding to the selected sensor node 112 (S300). Note that the sensor nodes 112 to be selected are not limited to full-test nodes, but include all sensor nodes 112 that have not yet reached full-test.

[0073] Here, the center storage unit 162 stores the positions of the respective meters 110. The network design unit 180 reads out the position of the specified meter 110 from the center storage unit 162 (S302).

[0074] Next, the network design unit 180 identifies the use area identifier of the use area to which the specified meter 110 belongs based on the read position of the meter 110 (S304). For example, the network design unit 180 refers to the use area database 170 stored in the center storage unit 162, identifies a section (planar polygon) that contains the position of the meter 110, and identifies the use area identifier of the use area corresponding to the section. Note that since the position of the sensor node 112 is limited to the vicinity of the meter 110, the use area identifier identified based on the position of the meter 110 corresponds to the land area information of the sensor node 112 corresponding to the meter 110.

[0075] Next, the network design unit 180 refers to the propagation distance table 172 stored in the center memory unit 162, and sets the propagation distance of the radio waves emitted from the selected sensor node 112 based on the identified use area identifier (S306).

[0076] Next, the network design unit 180 judges whether or not there is a sensor node 112 for which a propagation distance has not yet been set among the multiple sensor nodes 112 to be designed in the sensor network system 100 (S308). As a result, if there is a sensor node 112 for which a propagation distance has not yet been set (YES in S308), the network design unit 180 arbitrarily selects one sensor node 112 from the sensor nodes 112 for which a propagation distance has not yet been set, and repeats the meter specification process from S300.

[0077] On the other hand, if there is no sensor node 112 for which the propagation distance has not been set (NO in S308), the network design unit 180 ends the propagation distance setting process S100.

[0078] In the first embodiment, as shown in FIG. 5, the propagation distance setting process S100 is performed before the reference node setting process S200. However, the propagation distance setting process S100 may be performed after the reference node setting process S200. For example, after setting the reference node, the network design unit 180 may set the propagation distance of the radio wave emitted from the set reference node based on the use area identifier of the use area to which the reference node belongs. Also, the propagation distance setting process S100 may be performed during the distance condition determination process S202. For example, when the network design unit 180 extracts a sensor node 112 located within the propagation distance of the reference node, the network design unit 180 may set the propagation distance of the radio wave emitted from the extracted sensor node 112 based on the use area identifier of the use area to which the extracted sensor node 112 belongs.

[0079] As described above, in the design method for the sensor network system 100 according to the first embodiment, the use area identifier of the use area to which the first sensor node 112 corresponding to the first meter 110 belongs is identified based on the position of the first meter 110, the propagation distance of the radio waves emitted from the first sensor node 112 is set based on the identified use area identifier, and the group to which the sensor node 112 belongs is identified based on the propagation distance.

[0080] Therefore, in the design method for the sensor network system 100 according to the first embodiment, it is possible to set an appropriate propagation distance for each sensor node 112. As a result, in the sensor network system 100 constructed by this design method, wireless communication between the sensor nodes 112 can be stably performed. Therefore, according to the design method for the sensor network system 100 according to the first embodiment, a realistic sensor network system 100 can be constructed.

[0081] (Design method of the sensor network system 100 according to the second embodiment) In the first embodiment, the propagation distance of the sensor node 112 is set based on the use zone identifier. However, in addition to the use zone, there are also the building coverage ratio and the floor area ratio as indicators for dividing land. Therefore, in the second embodiment, the propagation distance of the sensor node 112 is set based on the use zone identifier, the building coverage ratio, and the floor area ratio.

[0082] More specifically, a land may be associated with a use zoning identifier for each predetermined section of land, and may also be associated with a building coverage ratio and a floor area ratio related to the use zoning identifier. The building coverage ratio indicates the ratio of the building area to the site area. The floor area ratio indicates the ratio of the three-dimensional volume of the building to the site area.

[0083] For example, in the use zoning database, a combination of a use zoning identifier, a building coverage ratio, and a floor area ratio is associated with each of the predetermined sections. For example, even if the use zoning identifier is the same for multiple sections, either or both of the building coverage ratio and the floor area ratio may be different for the multiple sections.

[0084] Fig. 8 is a diagram showing an example of the propagation distance table 172 in the second embodiment. Note that the specific numerical values ​​shown in Fig. 8 are merely examples, and are not limited to the illustrated numerical values, and may be set to any numerical values.

[0085] 8, in the propagation distance table 172 of the second embodiment, the use zone identifier, the building coverage ratio, the floor area ratio, and the propagation distance of the radio wave emitted from the sensor node 112 are associated with each combination of the use zone identifier, the building coverage ratio, and the floor area ratio. In other words, in the propagation distance table 172 of the second embodiment, the propagation distance of the radio wave emitted from the sensor node 112 installed in a section having a predetermined use zone identifier, a predetermined building coverage ratio, and a predetermined floor area ratio is defined for each combination of the use zone identifier, the building coverage ratio, and the floor area ratio.

[0086] As shown in FIG. 8, even if the use zoning identifier is the same, if the building coverage ratio or floor area ratio associated with the use zoning identifier is different, the propagation distance may be different.

[0087] Fig. 9 is a flowchart for explaining the flow of the propagation distance setting process (S100) of the second embodiment. As shown in Fig. 9, in the propagation distance setting process of the second embodiment, the identification process S404 and the setting process S406 are different from those of the first embodiment, and the other processes are the same as those of the first embodiment. Here, the processes different from those of the first embodiment will be explained, and the explanation of the processes the same as those of the first embodiment will be omitted.

[0088] As shown in FIG. 9, the network design unit 180 reads out the position of the specified meter 110 (S302), and then, based on the read out position of the meter 110, identifies the zoning identifier of the zoning of the section to which the specified meter 110 belongs, and the building coverage ratio and floor area ratio of the section to which the meter 110 belongs (S404).

[0089] For example, the network design unit 180 refers to the use zone database 170 stored in the center storage unit 162, and identifies the section (planar polygon) that includes the position of the meter 110. The network design unit 180 identifies the use zone identifier of the use zone corresponding to the identified section, the building coverage ratio corresponding to the identified section, and the floor area ratio corresponding to the identified section. Note that the use zone identifier, building coverage ratio, and floor area ratio identified based on the position of the meter 110 correspond to the land use zone information, building coverage ratio, and floor area ratio of the sensor node 112 corresponding to the meter 110.

[0090] After identifying the zoning identifier, the building coverage ratio, and the floor area ratio (S404), the network design unit 180 refers to the propagation distance table 172 and sets the propagation distance of the radio waves emitted from the selected sensor node 112 based on the identified zoning identifier, building coverage ratio, and floor area ratio (S406).

[0091] The propagation distance setting process S100 in the second embodiment may be performed after the reference node setting process S200, or may be performed during the distance condition determination process S202.

[0092] As described above, in the design method for the sensor network system 100 according to the second embodiment, the propagation distance of the radio waves emitted from the first sensor node 112 is set based on the zoning identifier, building coverage ratio, and floor area ratio associated with the position of the first meter 110.

[0093] Therefore, in the design method for the sensor network system 100 according to the second embodiment, the propagation distance in the sensor node 112 can be set in more detail for each sensor node 112. As a result, in the sensor network system 100 constructed by this design method, wireless communication between the sensor nodes 112 can be performed more stably. Therefore, according to the design method for the sensor network system 100 according to the second embodiment, a more realistic sensor network system 100 can be constructed.

[0094] In the second embodiment, a use zone identifier, a building coverage ratio, and a floor area ratio are associated with a specific section of land, and a combination of the use zone identifier, the building coverage ratio, and the floor area ratio is associated with a propagation distance in the sensor node 112. However, the provision of the floor area ratio may be omitted, and a use zone identifier and a building coverage ratio may be associated with the land for each specific section, and a combination of the use zone identifier and the building coverage ratio may be associated with a propagation distance in the sensor node 112. In this case, the propagation distance in the first sensor node 112 may be set based on the use zone identifier and the building coverage ratio associated with the position of the first meter 110. Also, the provision of the building coverage ratio may be omitted, and a use zone identifier and a floor area ratio may be associated with the land for each specific section, and a combination of the use zone identifier and the floor area ratio may be associated with a propagation distance in the sensor node 112. In this case, the propagation distance in the first sensor node 112 may be set based on the use zone identifier and the floor area ratio associated with the position of the first meter 110.

[0095] (Method of designing the sensor network system 100 according to the third embodiment) In the first and second embodiments, the propagation distance of any one sensor node 112 is set based on the use zone identifier of the use zone to which the sensor node 112 belongs. However, wireless communication between sensor nodes 112 may be affected not only by the installation environment of one sensor node 112 that performs wireless communication, but also by the installation environments of both sensor nodes 112 that perform wireless communication.

[0096] For example, when a first sensor node 112 and a second sensor node 112 that perform wireless communication belong to different use zones, the first sensor node 112 and the second sensor node 112 may be placed with a road between them. In such a case, since a wide space (e.g., a road) exists between the first sensor node 112 and the second sensor node 112, the propagation distance may be longer than when the first sensor node 112 and the second sensor node 112 belong to the same use zone and are placed close together.

[0097] Therefore, in the third embodiment, when deriving the propagation distance in the first sensor node 112, the propagation distance in the first sensor node 112 may be derived by taking into consideration not only the usage area to which the first sensor node 112 belongs, but also the usage area to which the second sensor node 112 attempting wireless communication with the first sensor node 112 belongs.

[0098] Fig. 10 is a diagram showing an example of the propagation distance table 172 in the third embodiment. Note that the specific numerical values ​​shown in Fig. 10 are merely examples, and are not limited to the illustrated numerical values, and may be set to any numerical values.

[0099] Here, the use area identifier of the use area to which the first sensor node 112 belongs may be called a first use area identifier. Also, the use area identifier of the use area to which the second sensor node 112 belongs may be called a second use area identifier.

[0100] 10, in the propagation distance table of the third embodiment, a combination of a first use area identifier and a second use area identifier and a propagation distance in a first sensor node are associated with each combination of the first use area identifier and the second use area identifier. In other words, in the propagation distance table 172 of the third embodiment, the propagation distance of the radio wave emitted from the first sensor node 112 is defined for each combination of a first use area identifier of the use area to which the first sensor node 112 belongs and a second use area identifier of the use area to which the second sensor node 112 that attempts wireless communication with the first sensor node 112 belongs.

[0101] As shown in FIG. 10, even if the first use area identifier is the same, if the second use area identifier is different, the propagation distance in the first sensor node 112 may be different.

[0102] Fig. 11 is a flowchart for explaining the flow of the propagation distance setting process (S100) of the third embodiment. As shown in Fig. 11, when the propagation distance setting process of the third embodiment is started, the network design unit 180 arbitrarily selects a first sensor node 112 from among a plurality of sensor nodes 112 to be designed in the sensor network system 100, and designates a first meter 110 corresponding to the selected first sensor node 112 (S500).

[0103] Next, the network design unit 180 reads out the location of the specified first meter 110 from the central storage unit 162 (S502).

[0104] Next, the network design unit 180 identifies the use zone identifier of the use zone to which the specified first meter 110 belongs based on the read position of the first meter 110 (S504). For example, the network design unit 180 refers to the use zone database 170 stored in the center storage unit 162, identifies a section (planar polygon) that includes the position of the first meter 110, and identifies the first use zone identifier of the first use zone corresponding to the section.

[0105] Next, the network design unit 180 designates the meter 110 that attempts wireless communication with the designated first meter 110 as the second meter 110 (S506).

[0106] Next, the network design unit 180 reads out the location of the specified second meter 110 from the central storage unit 162 (S508).

[0107] Next, the network design unit 180 identifies the use zone identifier of the use zone to which the specified second meter 110 belongs based on the read position of the second meter 110 (S510). For example, the network design unit 180 refers to the use zone database 170 stored in the center storage unit 162, identifies a section (planar polygon) that includes the position of the second meter 110, and identifies the second use zone identifier of the second use zone corresponding to the section.

[0108] Next, the network design unit 180 refers to the propagation distance table 172 stored in the center memory unit 162, and sets the propagation distance of the radio waves emitted from the selected first sensor node 112 based on the identified first and second use area identifiers (S512).

[0109] Next, the network design unit 180 determines whether or not there is a sensor node 112 for which a propagation distance has not yet been set among the multiple sensor nodes 112 to be designed in the sensor network system 100 (S514). As a result, if there is a sensor node 112 for which a propagation distance has not yet been set (YES in S514), the network design unit 180 arbitrarily selects a first sensor node 112 from among the sensor nodes 112 for which a propagation distance has not yet been set, and repeats the meter specification process from S500.

[0110] On the other hand, if there is no sensor node 112 for which the propagation distance has not been set (NO in S514), the network design unit 180 ends the propagation distance setting process S100.

[0111] The propagation distance setting process S100 in the third embodiment may be performed after the reference node setting process S200, or may be performed during the distance condition determination process S202.

[0112] As described above, in the design method for the sensor network system 100 according to the third embodiment, a first use area identifier of the use area to which the first sensor node 112 belongs is identified based on the position of the first meter 110, and a second use area identifier of the use area to which the second sensor node 112 corresponding to the second meter 110 belongs is identified based on the position of the second meter 110, and the propagation distance of the radio waves emitted from the first sensor node 112 is set based on the identified first use area identifier and second use area identifier.

[0113] Therefore, in the design method for the sensor network system 100 according to the third embodiment, the propagation distance in the sensor node 112 can be set in more detail for each sensor node 112. As a result, in the sensor network system 100 constructed by this design method, wireless communication between the sensor nodes 112 can be performed more stably. Therefore, according to the design method for the sensor network system 100 according to the third embodiment, a more realistic sensor network system 100 can be constructed.

[0114] (Design method of the sensor network system 100 according to the fourth embodiment) In the first embodiment, as shown in Fig. 5, groups are generated based on the distance condition and the condition of the number of sensor nodes 112. In the fourth embodiment, when generating these groups, one group may be generated with sensor nodes 112 that belong to the same use zone. That is, the network design unit 180 in the fourth embodiment may generate a group with the reference node and a predetermined number or less of sensor nodes 112 whose distance from the reference node satisfies a predetermined distance condition and which belong to the same use zone as the use zone to which the reference node belongs.

[0115] Fig. 12 is a flowchart for explaining the flow of processing executed by the network design unit 180 of the fourth embodiment. As shown in Fig. 12, in the fourth embodiment, the distance condition determination process S602 is different from that of the first embodiment, and the other processes are the same as those of the first embodiment. Here, the processes different from those of the first embodiment will be explained, and the explanation of the processes the same as those of the first embodiment will be omitted.

[0116] As shown in FIG. 12, after setting a reference node (S200), the network design unit 180 determines, for all sensor nodes 112 to be designed in the sensor network system 100, whether or not there are a predetermined number of sensor nodes whose distance from the reference node satisfies a predetermined distance condition and which belong to the same zoning area (S602).

[0117] Here, as in the first embodiment, the specified distance condition is whether a sensor node 112 is located within the propagation distance of the reference node from the reference node, or whether another sensor node 112 is located within the propagation distance of a sensor node 112 determined to be located within the propagation distance of the sensor node 112 determined to be located within the propagation distance.

[0118] The condition for belonging to the same use area is whether the use area identifier of the use area to which the reference node belongs is the same as the use area identifier of the use area to which the sensor node 112 determined to be located within the propagation distance of the reference node belongs, or whether the use area identifier of the use area to which the sensor node 112 determined to be located within the propagation distance belongs is the same as the use area identifier of the use area to which another sensor node 112 determined to be located within the propagation distance of the sensor node 112 determined to be located within the propagation distance belongs.

[0119] For example, the network design unit 180 extracts sensor nodes 112 whose distance from the reference node is within the propagation distance of the reference node and belongs to the same use area as the use area to which the reference node belongs. Furthermore, the network design unit 180 extracts sensor nodes 112 whose distance from the extracted sensor node 112 is within the propagation distance of the extracted sensor node 112 and belongs to the same use area as the use area to which the reference node belongs. The network design unit 180 repeats such processing until there are no sensor nodes 112 whose distance from the sensor node 112 on the reference side of the distance is within the propagation distance of the sensor node 112 on the reference side of the distance and belongs to the same use area as the use area to which the reference node belongs, or until the number of extracted sensor nodes 112 reaches a predetermined number.

[0120] Therefore, even if the distance condition is satisfied, if the sensor node 112 that satisfies the distance condition belongs to a different zone from the zone to which the reference node belongs, the sensor node 112 will not be extracted.

[0121] In this way, when a predetermined number of sensor nodes 112 that satisfy a predetermined distance condition and belong to the same use zone are extracted (YES in S602), the network design unit 180 generates a group with the reference node and the extracted sensor nodes 112 (S204). All sensor nodes 112 in the generated group belong to the same use zone as the reference node.

[0122] In addition, when the sensor nodes 112 that satisfy a predetermined distance condition and belong to the same usage area are extracted, and the number of the extracted sensor nodes 112 does not reach the predetermined number (NO in S602), the network design unit 180 determines whether the sensor node group consisting of the reference node and the extracted sensor nodes 112 that belong to the same usage area and are less than the predetermined number satisfies a predetermined distance condition with other groups that have already been generated (S208).

[0123] If the sensor node group here does not satisfy a predetermined distance condition with other groups (NO in S208), the network design unit 180 generates a group with the sensor node group, i.e., the reference node and the extracted sensor nodes 112 that belong to the same use area and are less than a predetermined number. Also, if the sensor node group here satisfies a predetermined distance condition with other groups (YES in S208), the network design unit 180 cancels the setting of the reference node and makes it a simple check-satisfied node (S212). In this case, a group including the reference node is not generated.

[0124] Then, the network design unit 180 finally associates the repeater 114 with the reference node of the generated group (S216).

[0125] The propagation distance setting process S100 in the fourth embodiment may be performed after the reference node setting process S200, or may be performed during the distance condition determination process S602.

[0126] As described above, in the design method for the sensor network system 100 according to the fourth embodiment, a reference node is designated, which is a sensor node 112 that is a candidate for installing a repeater 114 that relays between the sensor node 112 and the center device 116, and a group is generated with the reference node and a predetermined number or less of sensor nodes 112 whose distance from the reference node satisfies a predetermined distance condition and which belong to the same zoning as the reference node, and the repeater 114 is associated with the reference node of the generated group.

[0127] Therefore, in the design method for the sensor network system 100 according to the fourth embodiment, a group is generated of sensor nodes 112 having approximately the same propagation distance, making it easier to understand the constructed sensor network system 100.

[0128] 12, in the fourth embodiment as well, a propagation distance setting process (S100) is performed to set the propagation distance of the radio wave emitted from the sensor node 112 based on the use zone identifier. Therefore, in the design method for the sensor network system 100 according to the fourth embodiment, as in the first embodiment, an appropriate propagation distance can be set for each sensor node 112, and a realistic sensor network system 100 can be constructed.

[0129] 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 think of various modifications or alterations within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present invention.

[0130] For example, in the above-described embodiment, the center control unit 164 of the center device 116 functions as the network design unit 180. However, any computer other than the center device 116 may function as the network design unit 180. In this case, the use area database 170 and the propagation distance table 172 may be stored in a storage device of the computer, or the computer may acquire the use area database 170 and the propagation distance table 172 from the center storage unit 162.

[0131] Furthermore, the features of each embodiment may be combined as appropriate.

[0132] Also provided are programs that cause a computer to function as a device for designing the sensor network system 100, the meter 110, the sensor node 112, or the center device 116, as well as computer-readable storage media such as flexible disks, magneto-optical disks, ROMs, CDs, DVDs, and BDs on which the programs are recorded. Here, the program refers to data processing means written in any language or description method.

[0133] It should be noted that each process shown in this specification does not necessarily have to be performed in chronological order according to the order shown in the flowchart, and may include parallel or subroutine processes. [Explanation of symbols]

[0134] 100 Sensor Network System 110 meters 112 Sensor Nodes 114 Repeater 116 Central Equipment

Claims

1. A method for designing a sensor network system comprising a plurality of sensor nodes each corresponding to a plurality of meters, and a center device that collects meter information through the sensor nodes, the plurality of sensor nodes transmitting and receiving meter information through wireless communication between the sensor nodes, comprising the steps of: A land use zoning identifier indicating a use zoning classified into a plurality of types is associated with each predetermined parcel of land; the use zone identifier is associated with a propagation distance of a radio wave emitted from the sensor node, Identifying the use area identifier of a use area to which a first sensor node corresponding to the first meter belongs based on a position of the first meter; setting a propagation distance of radio waves emitted from the first sensor node based on the identified use zone identifier; A method for designing a sensor network system, comprising: identifying a group to which the sensor node belongs based on the propagation distance.

2. The land is associated with the use zoning identifier for each predetermined section of land, and is associated with a building coverage ratio related to the use zoning identifier; a combination of the zoning identifier and the building coverage ratio is associated with a propagation distance of a radio wave emitted from the sensor node; 2. The method for designing a sensor network system according to claim 1, further comprising the step of: setting a propagation distance of radio waves emitted from the first sensor node based on the zoning identifier and the building coverage ratio associated with the position of the first meter.

3. The land is associated with the use zoning identifier for each predetermined section of land, and is associated with a floor area ratio related to the use zoning identifier; a combination of the use zone identifier and the floor area ratio is associated with a propagation distance of a radio wave emitted from the sensor node; 3. The method for designing a sensor network system according to claim 1, further comprising: setting a propagation distance of radio waves emitted from the first sensor node based on the use zone identifier and the floor area ratio associated with the position of the first meter.

4. identifying a first use area identifier of a use area to which the first sensor node belongs based on a position of the first meter, and identifying a second use area identifier of a use area to which a second sensor node corresponding to the second meter belongs based on a position of a second meter; 2. The method for designing a sensor network system according to claim 1, further comprising the step of: setting a propagation distance of radio waves emitted from the first sensor node based on the identified first and second use zone identifiers.

5. A reference node is designated as the sensor node that is a candidate for installing a relay that relays between the sensor node and the center device; generating a group including a predetermined number or less of the sensor nodes whose distance from the reference node satisfies a predetermined distance condition and which belong to the same use zone as the use zone to which the reference node belongs, and the reference node; The method for designing a sensor network system according to claim 1 , further comprising the step of: associating the repeater with the reference node of the generated group.

Images