TW201431416A - Sensor network system and communication channel setting method - Google Patents

Abstract

This sensor network system (100) is equipped with: multiple sensor nodes (110) which are associated with smart meters; gateway devices (112) which collect data from the multiple sensor nodes and distribute data to the sensor nodes; and a center device (114) which receives data from the gateway devices and transmits data to the gateway devices. Radio communication is executed between the sensor nodes and between the sensor nodes and the gateway devices, and radio communication via a paid communication network is executed between the gateway devices and the center device.

Description

Sensor network system, and communication path setting method

The present invention relates to a sensor network system for collecting information from a plurality of sensor nodes, and a communication path setting method.

In order to settle the amount of gas or electricity consumed by the demander, the gas dealer or the electric power supplier may arrange a gas meter or a power meter at a required place. In addition, in recent years, it has a communication function, and can perform two-way data communication with a gas business or a power supplier, and automatically perform a remote look-up of gas or electricity usage, or can be obtained from a gas business or The smart meter that controls the home appliance of the demand side is attracting attention. The smart meter can also be utilized as a source of information needed to improve the security or utilization efficiency of a live network such as gas or electricity.

Further, various means have been proposed in order to realize the above-described data communication between the smart meter and the gas business or the electric power supplier. For example, consider (1) setting up a close-range wireless device in a smart meter to form a mesh network, or (2) forming a star network by using a mobile phone network such as 3G or LTE (Long Term Evolution). , or (3) by power line communication Form a star network.

In addition, as a network-type network application, the random communication caused by the backbone network and the wireless LAN is combined, and the technology for stably utilizing the smart meter is switched by switching to random communication in the event of a backbone network failure. Known (for example, Patent Document 1). Further, a technique related to routing of a network has also been disclosed (for example, Patent Document 2).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2012-065422

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2012-105258

However, in the above (1) mesh type network, the design cost of the coverage area of the short-range wireless device, the equipment and installation cost of the base station collecting data from the wireless device, and the maintenance management cost of the base station are expensive. The problem has emerged. In particular, it is extremely difficult to maintain the management of the area, such as the regional design of the base station and the resetting or burying of the poles of the base station.

Moreover, the mesh type network is required to be set up close to each other by the wireless device, so if the wireless device is not configured, the network cannot operate. Therefore, it takes time until it can work, and investment recovery will be delayed.

Moreover, in the star network caused by (2) mobile phone network, since the communication fee is required for each movement of the data, if the communication is performed by all the mobile phone terminals, the cost will be enormous. The communication cost described above loses the meaning of automation if it exceeds the manual checklist. Moreover, the mobile phone terminal requires a lot of power, so the battery is not enough, and the power supply means must be separately prepared.

Moreover, in the star network caused by (3) power line communication, when connecting to a gas meter, the danger of lightning is unavoidable.

The present invention has been made in view of the above problems, and an object thereof is to provide a sensor network system capable of suppressing equipment cost or area design cost to a minimum, and at the same time achieving stable operation of a smart meter and improvement of obstacle tolerance of the system. And the communication path setting method.

In order to solve the above problem, the sensor network system of the present invention is characterized in that: a complex sensor node corresponding to a smart meter; and a gateway machine collects data from a plurality of sensor nodes. And distributing data to the sensor node; and the central device receives data from the gateway machine and transmits data to the gateway machine; performing wireless communication between the sensor nodes and between the sensor node and the gateway machine, The wireless communication through the payment communication network is performed between the gateway machine and the central device.

The sensor node system may also have a ranking setting unit that associates the sensor node located at a position where the gateway device can communicate wirelessly with the gate device, and is located in the rank n (n=1 or more). Integer) wireless The sensor node that has the location of the communication and has not yet been associated with the ranks 1~n is associated with the rank n+1.

The ranking setting unit can also rank the next one of the highest-ranking sensor nodes among the sensor nodes that can wirelessly communicate once it is unable to communicate wirelessly with the higher-ranking sensor nodes. , establish correspondence.

The ranking setting unit can also limit the ranking of the sensor nodes to the predetermined ranking.

The sensor node system may also have: a data sending and receiving department, which receives data from a sensor node that ranks higher than itself, broadcasts the data, and if it is not ranked lower than itself in the range of wireless communication When the sensor node is present, the broadcast of the data is restricted.

In order to solve the above problem, the communication path setting method of the present invention is characterized in that: a complex sensor node corresponding to a smart meter is provided; and a gateway device collects data from a plurality of sensor nodes, and Distributing data to the sensor node; and the central device, which is a sensor network system that receives data from the gateway machine and transmits data to the gateway machine, between the sensor nodes and the sensor nodes and gates Wireless communication is performed between the machines, and the wireless communication through the payment communication network is performed between the gateway device and the central device; the sensor nodes are located at the sensor nodes that can communicate with the gateway device in wireless communication, and ranking 1 Correspondence is established, and a sensor node located at a position that can be wirelessly communicated with the rank n (n=1 or more) and has not yet been associated with the ranks 1~n is associated with the rank n+1.

According to the present invention, the equipment cost or the area design cost can be suppressed to a minimum, and the stable operation of the smart meter and the obstacle tolerance of the system can be achieved.

100‧‧‧Sensor Network System

110‧‧‧ sensor node

112‧‧‧gate machine

114‧‧‧Center installation

116‧‧‧Base station

130‧‧‧Communication Department

132‧‧‧Memory Department

134‧‧‧Central Control Department

142, 162‧‧‧Beacon Department

144, 164‧‧‧Form Generation Department

146, 166‧‧‧ form delivery department

148, 168‧‧‧Information sent to the receiving department

150‧‧‧Communication Department

152‧‧‧Memory Department

154‧‧‧Central Control Department

160‧‧‧ Ranking Setting Department

170‧‧‧Lower Ranking

172‧‧‧Upper ranking table

FIG. 1 is an explanatory diagram of a schematic configuration of a sensor network system.

[Fig. 2] An explanatory diagram of a connection relationship of a sensor network.

[Fig. 3] A functional block diagram of a schematic structure of a gateway machine.

[Fig. 4] An explanatory diagram for explaining a lower ranking table.

[Fig. 5] A functional block diagram of a schematic configuration of a sensor node.

[Fig. 6] An explanatory diagram for explaining a ranking table.

[Fig. 7] A flow chart showing the processing flow of the communication path setting method.

[Fig. 8] A flow chart showing the processing flow of the communication path setting method.

[Fig. 9] A flow chart showing the processing flow of the communication path setting method.

[Fig. 10] A flow chart showing the processing flow of the communication path setting method.

FIG. 11 is an explanatory diagram of a positional relationship between a gateway device and a sensor node when the ranking is limited to two.

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The method, material, and the method shown in the embodiment The specific numerical values and the like are merely exemplified for easy understanding of the invention, and are not intended to limit the invention unless otherwise stated. In the present specification and the drawings, elements that have substantially the same functions and configurations are denoted by the same reference numerals, and the description thereof will not be repeated, and the elements that are not directly related to the present invention are not shown.

(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 is comprised of a complex sensor node 110, a plurality of gateway devices 112, and a central device 114. For example, the sensor network system 100 is associated with a smart meter. The smart meter is used when a gas supplier supplies gas to a needr or supplies power to a power supplier from a power supplier, and is a device that automatically checks the amount of gas or electricity used.

The sensor node 110 corresponds to the smart meter, and at least performs the receiving and receiving of the data used on the smart meter. The gateway machine 112 and the sensor node 110, in the same manner, can correspond to the smart meter, collect data from the 1 or complex sensor nodes 110, and distribute the data to the 1 or complex sensor nodes 110. The central device 114 is constituted by a computer or the like, and is a device on the manager side of the sensor network system 100 such as a gas business or a power supplier, and collects data of one or a plurality of gateway devices 112, and Information is distributed to 1 or a plurality of gateway machines 112.

Here, the gateway device 112 and the central device 114 pass through, for example, a mobile telephone network or a PHS (including a base station 116). Handyphone System), etc., performs wireless communication with an existing payment communication network that generates communication charges with the amount of communication. Further, between the sensor nodes 110 and the sensor node 110 and the gateway device 112, wireless communication is performed through, for example, a wireless system (U-Bus Air) using a smart meter of the 920 MHz band. The wireless communication between the sensor nodes 110 and the sensor node 110 and the gateway machine 112 is intended to be free, but whether it is charged or free, as long as the communication cost is higher than the gateway device 112 and the central device 114. The wireless communication between them is still low. By such wireless communication, the gateway device 112 is connected to the central device 114 via the payment communication network, and is connected to the respective sensor nodes 110 via the wireless system for the smart meter.

In the present embodiment, a smart meter is disposed for each of the plurality of users. In addition, the smart meter system is respectively configured to correspond to the sensor node 110 or the gateway device 112, and the central device 114 collects the information of the smart meter through the sensor node 110 or the gateway device 112, or Control the smart meter. Therefore, the sensor node 110 or the gateway machine 112 is configured at any position where the person in need exists.

Here, in the gateway device 112, the wireless system and the payment communication network for the smart meter are used together, and the base station dedicated to the wireless system for the smart meter is not separately provided, and the existing payment communication network can be used simply and inexpensively. Communication between the central device 114 and the sensor node 110 is established. Moreover, in the combination of the gateway device 112 and the complex sensor node 110 therearound, only the gateway device 112 utilizes a pay communication network, and all other sensor nodes 110 utilize smart meters that do not generate communication fees. Wireless system. Therefore, communication costs can be drastically reduced.

The wireless system for smart meters is designed to be close-range wireless, so wireless communication consumes less power. Therefore, the power of the sensor node 110 can be served by a battery or the like, which can reduce the power consumption of the sensor network system 100. Moreover, the payment communication network is easier to consume power than the wireless system for smart meters, and therefore requires a large capacity battery or another power supply. However, the number of gateway machines 112 is much less than that of the sensor node 110, so the power consumption can be reduced to a very low level compared to the case where the mobile phone network is utilized from all smart meters. Hereinafter, the configuration of the sensor node 110 and the gateway machine 112 will be described in detail.

(Connection relationship of sensor network system 100)

2 is an explanatory diagram of a connection relationship of a sensor network. As shown in FIG. 2, in the present embodiment, a plurality of gateway devices 112 are connected to the center device 114, and a plurality of sensor nodes 110 are connected to the gateway device 112.

However, as described above, the sensor node 110 is implemented in short-range wireless, and thus does not necessarily have to be able to establish wireless communication with the gateway machine 112. In this case, the sensor node 110 is connected to the gateway machine 112 as a hop for other sensor nodes 110 that are capable of wireless communication.

In the sensor network system 100, in order to represent the number of hops of the sensor node 110, each sensor node 110 is assigned a periodic ranking by which the sensor node 110 is managed. For example, as shown in FIG. 2, the gateway machine 112 is assumed to rank 0, which will be with the gateway machine 112. The sensor node 110 that is directly connected without a hop is set to rank 1. Later, as the number of hops increases, the rank's ordinal value is incremented by one each time. Here, the higher the ranking, the smaller the ordinal number, the lower the ranking, the larger the ordinal number.

When the ranking is given as shown in FIG. 2, the data exchanged between the center device 114 and each of the sensor nodes 110 is sequentially hopped in accordance with the ranking. For example, when data is communicated from the central device 114 to the sensor node 110 of rank 2, the data is communicated via the gateway node 112 corresponding to rank 0 and the sensor node 110 of rank 1. The following is an example of a schematic construction of gateway machine 112 and sensor node 110, illustrating how the connection relationship on sensor network system 100 is established.

(Gateway Machine 112)

3 is a functional block diagram of a schematic construction of the gateway machine 112. The gateway device 112 includes a communication unit 130, a storage unit 132, and a central control unit 134. The communication unit 130 establishes wireless communication with the central device 114 (base station 116) through the payment communication network, and establishes wireless communication with the sensor node 110. The memory unit 132 is composed of a ROM, a RAM, a flash memory, an HDD, etc., and memorizes a program or various materials used in the gateway device 112, for example, a lower ranking table to be described later.

The central control unit 134 is composed of a CPU or a DSP (Digital Signal Processor), and controls the entire gateway device 112 by using a program stored in the storage unit 132. Further, the central control unit 134 functions as the beacon transmitting unit 142, the table generating unit 144, the form transmitting unit 146, and the data transmitting and receiving unit 148.

The beacon transmitting unit 142 transmits information necessary for identifying itself, for example, a beacon containing an identification element (ID) and a ranking (ranking 0), every predetermined time, for example, every 5 seconds, through the communication unit. 130 is sent (broadcast) to the outside.

The table generation unit 144 generates a lower ranking table in response to a beacon received from the sensor node 110 every predetermined time, for example, every hour.

Fig. 4 is an explanatory diagram for explaining a lower ranking table. The lower ranking table 170 includes: the identification element of each of the sensor nodes 110 that received the beacon 1 or the plurality of rankings 1, the ranking (fixed to rank 1), the electric field strength, the battery residual amount (or the past communication times) ), lower ranking table 170. Here, the lower ranking table 170 also contains a lower ranking table 170 for the lower ranked sensor nodes 110. Accordingly, a lower ranking table 170 associated with all of the sensor nodes 110 that can communicate information through the gateway machine 112 is included.

Referring back to FIG. 3, the form transmitting unit 146 transmits the latest lower ranking table 170 held in the gateway device 112 to the center device 114 every predetermined time, for example, every day (24 hours).

The data transmission and reception unit 148 receives the data from the center device 114 through the communication unit 130 at the transmission timing of the beacon caused by the beacon transmission unit 142, and transmits (broadcasts) the received data. . Further, the data transmission and reception unit 148 transmits the data received from the sensor node 110 to the center device 114.

(sensor node 110)

FIG. 5 is a schematic diagram of a functional block formed by the sensor node 110. The sensor node 110 includes a communication unit 150, a storage unit 152, and a central control unit 154. The communication unit 150 establishes wireless communication with the gateway machine 112 or other sensor nodes 110. The memory unit 152 is composed of a ROM, a RAM, a flash memory, an HDD or the like, and stores a program or various materials used in the sensor node 110, such as a lower ranking table 170 or a higher ranking table to be described later.

The central control unit 154 is composed of a CPU or a DSP, and controls the entire sensor node 110 by using a program stored in the storage unit 152. Further, the central control unit 154 functions as the ranking setting unit 160, the beacon transmitting unit 162, the table generating unit 164, the form transmitting unit 166, and the data transmitting and receiving unit 168.

The ranking setting unit 160 sets the ranking of its own sensor node 110. Specifically, the ranking setting unit 160 associates the sensor node 110 located at a position where the gateway device 112 can wirelessly communicate with the rank 1 and will be located in the rank n (n=1 or more integers) wirelessly. The sensor node 110 that has the location of the communication and has not yet been associated with the ranks 1~n is associated with the rank n+1. That is, the sensor nodes 110 located at locations that are wirelessly communicable with the gateway device 112 corresponding to rank 0 are all ranked 1 and are located at the sensor node 110 that can be ranked n (n is an integer greater than 1). The sensor nodes 110 at the location of the wireless communication are all set to rank n+1.

Therefore, the ranking setting unit 160 is able to wirelessly communicate with itself. Among the gateway machines 112 or other sensor nodes 110, the first or complex sensor nodes 110 ranked highest (the ordinal is the minimum) are set as the upper ranked sensor nodes 110 (or the gateway machine 112). ), set the ranking of the next one as your own ranking. As such, all of the sensor nodes 110 that can communicate wirelessly with the gateway machine 112 or the sensor node 110 can be ranked.

At this time, as shown in FIG. 2, the sensor node 110 is in communication with the first or plural sensor node 110 ranked first than itself, and the first or complex sensor node 110 ranked lower than the lower one. . In addition, it is not communicatively connected to the sensor node 110 of the same ranking.

In this way, the sensor node 110 capable of wireless communication has a plurality of upper and lower bits, whereby the sensor network system 100 can ensure other functions even if the sensor node 110 loses function due to something. Communication route. Therefore, the stable operation of the smart meter and the improvement of the obstacle tolerance of the system can be achieved.

Incidentally, the gateway device 112 and the sensor node 110, or the sensor nodes 110 are connected to each other by wireless communication, so that wireless communication is possible with the radio wave environment or the output power of the sensor node 110. The sensor node 110 becomes wireless communication, or the sensor node 110 that is otherwise incapable of wireless communication becomes wirelessly communicable. Therefore, the sensor node 110 migrates to the rank that it should be in accordance with the situation at this time, and updates the sensor node 110 of the upper rank or the sensor node 110 of the lower rank.

For example, the ranking setting unit 160 is once unable to compare with the ranking. The upper sensor node 110 wirelessly communicates, and among the wireless communication sensor nodes 110, the ranking of the lower one of the sensor nodes 110 ranked highest (the ordinal is the minimum value) is regarded as its own ranking. And set. Once their rankings are migrated, the sensor nodes 110 that can be ranked with their own wireless communication will also migrate. As a result, the management of the sensor node 110 capable of wireless communication can be maintained.

The beacon transmitting unit 162 transmits the information required to identify itself, for example, the beacon including the identification element and the ranking set by the ranking setting unit 160, for each predetermined time, for example, every 5 seconds, through the communication unit. 150 is sent (broadcast) to the outside.

Referring back to FIG. 5, the table generation unit 164 generates the upper ranking table and the lower ranking table 170 with the beacons received from the other sensor nodes 110 every predetermined time, for example, every hour. The lower ranking table 170 is a lower box equal to the lower ranking table 170 used in the gateway machine 112, so only the upper ranking table will be described here.

Fig. 6 is an explanatory diagram for explaining the upper ranking table. The upper ranking table 172 includes: the identification element, the ranking, the electric field strength, and the battery residual amount (or the number of past communication times) of each of the upper one or the plurality of sensor nodes 110.

For example, as shown in FIG. 6(a), in the sensor node 110 of the ranking 1, since the ranking setting unit 160 sets itself to the rank 1, the table generating unit 164 indicates that the ranking is in the ranking table 172. The gateway machine 112 of 0. Further, as shown in FIG. 6(b), in the sensor node 110 of the ranking 2, since the ranking setting unit 160 sets itself to rank 2, Therefore, the table generating unit 164 indicates the sensor node 110 which is the rank 1 in the upper ranking table 172.

The form server 166 is not included in the information held by the sensor node 110 for each predetermined time, for example, every hour, as required by the gateway machine 112 or other central node 110. It is included in the beacon (identification element, ranking) (light can not be transmitted by the beacon), but the information necessary for the generation of the lower ranking table 170, for example, the battery residual of the sensor node 110, and the sensor node The latest lower ranking table 170 of 110 (hereinafter referred to as insufficient information) is sent to the required gateway machine 112 or sensor node 110.

The data sending and receiving unit 168 receives the data from the gateway device 112 or the sensor node 110 through the communication unit 150 at the signaling timing of the beacon caused by the beacon transmitting unit 162, and receives the received data. The data is transmitted (broadcast) to other sensor nodes 110. Further, the data transmission and reception unit 168 transmits the data received from the sensor node 110 to the gateway device 112 or other sensor node 110.

However, as described above, if the sensor node 110 is unable to communicate directly with the gateway device 112, it is connected to the gateway device 112 with the other sensor nodes 110 that can communicate wirelessly as a hop. Thus, the data delivery and reception unit 168 receives or transmits the data based on the ranking set for each of the sensor nodes 110. Here, it is divided into a data sub-chain from the central device 114 to the sensor node 110 of the transmitting object, and a data upper chain from the sensor node 110 to the central device 114 to explain the connection path (routing) of the data. .

In the lower chain, first, the central device 114 sends the identifier of all the sensor nodes 110 included in the lower-level ranking table 170 to the sensor node 110 of the transmitting object, and sends it to the lower ranking. The gateway machine 112 of Table 170. The gateway machine 112 transmits data to the sensor node 110 of rank 1, and sequentially causes the lower ranked sensor node 110 to transmit the data to communicate the data to the sensor node 110 of the final destination.

At this time, the data transmission and reception sections 148 and 168 of the gateway device 112 or the respective sensor nodes 110 are considered to be dispersed by the sensor nodes 110 and b which have the largest average electric field intensity. The sensor nodes 110, c. function of one or a plurality of parameters selected in such sensor nodes 110 in which the communication traffic is dispersed, and the optimal sensor node 110 is selected as the target of the transmission.

Moreover, the sensor node 110, which is the object of the transmission, receives the data, and responds to the data, d. returns by means of the arrival of the data, or e. returns the highest electric field strength in the upper ranking table 172. , will choose one of the means. At this time, if the loopback fails, another route is selected and resend, and the arrival rate of the loopback can be improved.

In the uplink, the data transmission and reception unit 168 of the sensor node 110 transmits the data through the counterpart with the highest electric field strength in the upper ranking table 172, and the received sensor node 110 is also the highest through the electric field strength. Send the information to the other party. At this time, the sensor node 110 included in the route will express its own identification element in the message. At this time, if the transmission fails, another route is selected and re-sent, and the arrival rate of the transmission can be improved. Moreover, the central device 114 that receives the data transmits the response data in the same way according to the route shown in the message.

(Communication path setting method)

In the above-described sensor network system 100, regarding each wireless communication, there are: (1) beacon transmission every 5 seconds, and (2) updating the upper ranking table 172 and the lower ranking table 170 every one hour, ( 3) The first-day gate device 112 transmits the three kinds of communication timings of the lower ranking table 170 to the center device 114.

(1) The reason why the beacon is transmitted every 5 seconds is that in order to increase the reaction time of the entire sensor network system 100, the data transmission and reception unit 148, 168 is in the beacon transmission department when a data transmission accident occurs. At the timing of the beacon transmission caused by 162, the data will be sent at the latest within 5 seconds of the accident.

(2) The reason why the upper ranking table 172 and the lower ranking table 170 are updated every one hour is that, for the purpose of the soundness of the sensor network system 100, the gateway machine 112 confirms the lower ranking table 170 every hour. If it is updated, if there is a change (when an alarm occurs), the message is sent to the center device 114.

(3) The reason why the first-day gate device 112 transmits the lower ranking table 170 to the center device 114 is to confirm that the sensor network system 100 has a normal function. Here, by setting the transmission of the lower ranking table 170 from the gateway device 112 to every day, the use of the payment communication network of the gateway device 112 can be minimized, and the communication can be reduced. this.

In this way, the information of the center device 114 and the sensor node 110 can be quickly transmitted while reducing the communication cost.

7 to 10 are flowcharts showing a processing flow of the ranking setting of the sensor node 110 in the communication path setting method. In particular, FIGS. 7 and 8 illustrate the processing of the gateway device 112, and FIGS. 9 and 10 illustrate the processing of the sensor node 110. Further, FIGS. 7 and 9 illustrate the periodicity by means of a timer. The timing interruption processing occurs, and FIG. 8 and FIG. 10 are diagrams showing the reception cancellation processing that is interrupted as the beacon is received.

As described above, the sensor node 110 migrates as the mobile or radio wave environment changes. However, the gateway machine 112 does not have a ranking transition (fixed to rank 0). Further, in order to count the passage of time, the machine day counter, the machine time counter, and the node time counter are activated.

Referring to Fig. 7, a timing break occurs in the gateway machine 112 every predetermined time, here every 5 seconds. The table transmitting unit 146 determines whether or not the count value of the machine day counter has reached a value equivalent to one day (1 day/5 seconds = 17280) (S200).

As a result, when the machine day counter reaches the first day (YES in S200), the form transmitting unit 146 transmits the lower ranking table 170 managed by itself to the center device 114 via the payment communication network (S202). Then, the form transmitting unit 146 resets the machine day counter (S204). Further, if the machine day counter has not reached 1 day (NO in S200), the form transmitting unit 146 increments the machine day counter. 1 (S206). In this way, the latest lower ranking table 170 is uploaded to the central device 114 every day.

Next, the table generation unit 144 determines whether or not the count value of the machine time counter has reached a value of, for example, one hour (1 hour/5 seconds = 720) (S208). As a result, when the machine counter reaches 1 hour (YES in S208), the table generation unit 144 sets the device update permission flag to ON (S210). The machine update permission flag is used to update the flag required for the information received from the sensor node 110. Then, the table generation unit 144 resets the machine time counter (S212). When the machine time counter has not reached 1 hour (NO in S208), the table generation unit 144 increments the machine time counter by 1 (S214). In this way, the lower ranking table 170 can be updated every hour.

Next, the beacon transmitting unit 142 transmits information necessary for identifying itself, for example, a beacon including an identification element and a ranking (corresponding to rank 0) (S216), and ends the timing interruption processing. Here, since the burst period is 5 seconds, the beacon is transmitted every 5 seconds.

Referring to Figure 8, if the gateway machine 112 receives a beacon from the sensor node 110, a reception chopping occurs. The table generation unit 144 determines whether or not the device update permission flag is ON (S250). As a result, if the machine update permission flag is ON, that is, if the update timing every one hour has come (YES in S250), the table generation unit 144 updates its lower position based on the received beacon. The ranking table 170 (S252) sets the machine update permission flag to OFF (S254). Further, if the device update permission flag is not ON (NO in S250), the reception reception processing is ended.

Specifically, the table generation unit 144 performs the addition of the sensor node 110 that is newly wirelessly connectable, the overwriting of the existing sensor node 110, and the sensor node 110 that has been set but cannot be wirelessly communicated. delete. At this time, the table generation unit 144 acquires the insufficient information (the remaining battery level of the sensor node 110 of the rank 1 and the lower ranking table 170) by wireless communication, and measures the electric field intensity of each of the sensor nodes 110 of the rank 1.

Referring to Figure 9, a timing break occurs in the sensor node 110 for every predetermined time, here every 5 seconds. The table generation unit 164 determines whether or not the count value of the counter has reached a value of, for example, one hour (1 hour/5 seconds = 720) (S300). As a result, when the node-time counter reaches 1 hour (YES in S300), the table generation unit 164 sets the node update permission flag to ON (S302). The node update permission flag, like the machine update permission flag, is a flag required to update information received from other sensor nodes 110. Then, the table generation unit 164 resets the node time counter (S304).

Further, when the node time counter has not reached 1 hour (NO in S300), the table generation unit 164 increments the node time counter by 1 (S306). In this way, the lower ranking table 170 can be updated every hour.

Next, the beacon transmitting unit 162 transmits information necessary for identifying itself, for example, a beacon containing the identification element and the ranking (S308), and ends the timing interruption processing. Here, since the burst period is 5 seconds, the beacon is transmitted every 5 seconds.

Referring to FIG. 10, if the sensor node 110 receives a beacon from another sensor node 110, a reception chopping occurs. The ranking setting unit 160 determines whether or not the node update permission flag is ON (S350). As a result, if the node update permission flag is ON, that is, if the update timing every one hour has arrived (YES in S350), it is determined whether or not the received beacon has a ranking higher than its own ranking. The sensor node 110 (S352), if there is the upper ranked sensor node 110 (YES in S352), the process moves to step S354, and if there is no upper ranked sensor node 110 (NO in S352), Then the processing proceeds to step S358. Further, if the node update permission flag is not ON (NO in S350), the reception reception processing is ended.

If there is a sensor node 110 ranked higher, the ranking setting unit 160 determines whether there is a sensor node 110 whose ranking is higher than or equal to 2 or higher (S354), and if there is a sensor node 110 that ranks above 2 or higher. (YES in S354), the ranking setting unit 160 sets the ranking of the next one of the sensor nodes 110 as its own ranking, so that the ranking of the sensor node 110 is shifted to the upper position (S356). Further, if there is no sensor node 110 that ranks above 2 or higher (NO in S354), the processing proceeds to step S364.

Further, if there is no upper-level sensor node 110 (NO in S352), the ranking setting unit 160 determines whether or not there is a sensor node 110 (identifier) in the received beacon (S358), if There is a sensor node 110 (YES in S358), which sets the ranking of the next one of the highest ranked sensor nodes 110 among the wirelessly connectable sensor nodes 110. In order to shift the ranking of the sensor node 110 to the lower position (S360), the process proceeds to step S364. Further, if there is no sensor node 110 (NO in S358), the ranking setting unit 160 sets itself to the sensor node 110 that is not ranked, that is, the single-sensor node 110 (S362), which will be processed. The process proceeds to step S364.

Then, the table generation unit 164 updates its own upper ranking table 172 based on the received beacon (S364), and updates the lower ranking table 170 (S366), and sets the node update permission flag to OFF (S368). The end of the reception will be interrupted. Specifically, the table generation unit 164 performs the addition of the sensor node 110 that is newly wirelessly connectable, the overwriting of the existing sensor node 110, and the sensor node 110 that has been set but cannot be wirelessly communicated. delete. At this time, the ranking setting unit 160 acquires the insufficient information (the remaining battery level of the sensor node 110 and the lower ranking table 170) by wireless communication, and measures the electric field intensity of each of the sensor nodes 110.

(limitation of ranking)

In the above embodiment, the ranking is achieved without restriction, and the data transmission rate is improved. However, since the smart sensor corresponding to the sensor node 110 of the present embodiment is fixed for each user, it is possible to manage (master) its position. Therefore, by adjusting the number of gateway machines 112 or the distance between the gateway machines 112, the lowest position of the ranking can be limited. Here, for example, the ranking setting unit 160 is an example in which the ranking of the sensor node 110 is limited to a predetermined ranking (the ordinal number is equal to or less than a predetermined value).

The lowest position in this ranking is determined when When the ranking of the user is equal to the lowest position (the maximum number of the ordinal) (=end sensor node), since there is no sensor node 110 lower than the lower position, the data of the sensor node 110 is sent to the receiving unit 168. There is no need to send (broadcast) data. In this way, the power consumption of the sensor node 110 whose rank is the largest can be reduced. The following example illustrates an example of limiting the ranking to 2 or less.

FIG. 11 is an explanatory diagram of the positional relationship between the gateway device 112 and the sensor node 110 when the ranking is limited to two. Here, it is assumed that the sensor node 110 is arranged in a mesh shape, and the gateway machine 112 is disposed at an arbitrary position.

As shown in FIG. 11(a), the square 400 formed by the four sensor nodes 110 has a side length T _Node and an area S _Node , and the radius of the circle 402 corresponding to the communicable range of the gateway machine 112. Is R _1st and the area is S _1st . Under the condition of S _1st >>S _Node , the number N _1st of the sensor nodes 110 existing in S _1st can be approximated by the following formula 1.

N _1st =S _1st /S _Node =(π.R _1st ² )/T _Node ² ... (Expression 1 )

Here, in order to make the ratio of the gateway device 112 to the sensor node 110 about 1/10, if N _1st >>10, the relationship of the following Formula 2 is derived.

(π.R _1st ² )/T _Node ² >>10 R _1st /T _Node >>√(10/π)≒1.8...(Expression 2 )

If the radius R _1st of the circle 402 corresponding to the communication range of the gateway device 112, that is, the electric field strength (depending on the power of the transmitting side and the sensitivity of the receiving side) is 1.8 of the distance T _Node between the sensor nodes 110. When the ratio is more than (for example, 20 mW or more), one of the gateway devices 112 can wirelessly communicate with the ten sensor nodes 110 without a hop.

Further, as shown in FIG. 11(b), when the distance between the gateway devices 112 is set to be twice the radius R _1st (disposed to the circle 402 corresponding to the communication range of the gateway device 112) It can be seen that all of the sensor nodes 110 around it exist in a circle 402 having a radius R _1st centered on one gate machine 112 and at the same time as a radius centered on the other gateway machine 112. 2 × R _1st in the circle 404. This means that even if one of the gateway devices 112 has no function due to something like replacement, it can be connected to the gateway device 112 by migrating to rank 2 and passing through the hop. Therefore, the stable operation of the smart meter and the improvement of the obstacle tolerance of the system can be achieved.

Thus, even if the ranking is limited to two, one gateway machine 112 can manage ten sensor nodes 110. Moreover, even if the gateway machine 112 or the sensor node 110 temporarily loses functionality due to repair or replacement, the communication path can be maintained through the other sensor nodes 110, thereby maintaining the operation of the sensor network system 100.

Therefore, for example, when an existing gas meter or electric power meter is replaced with a smart meter, it can be replaced by 10 times (the life of the gas meter is 10 years, and it is replaced once a year). For example, you can replace a 10% gas meter with wisdom at intervals of 1 interval. Type gauge. At this time, the smart meter is associated with the gateway machine 112. Then, after that, it is only necessary to replace the 10% gas meter with the smart meter every time, so that it corresponds to the sensor node 110. As such, the sensor network system 100 can be readily adapted.

As described above, with the sensor network system 100 and the communication path setting method of the present embodiment, the equipment cost or the area design cost can be minimized, and the stable operation of the smart meter and the system obstacle can be achieved. Increased patience.

The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is of course not limited to the embodiments described above. As long as it is a practitioner, various modifications or corrections are naturally conceivable within the scope of the patent application, and these are of course also within the technical scope of the present invention.

Further, a program for causing the computer to function as the gateway device 112 or the sensor node 110 or a computer-readable floppy disk, optical disk, ROM, CD, DVD, BD, etc. for recording the program may be provided. Memory media. Here, the program refers to the data processing method written in any language or writing method.

Further, the respective items in the communication path setting method of the present specification are not necessarily processed in a time-series manner in the order described in the flowchart, and may be parallel or include a sub-normal processing.

[Possibility of industrial use]

The present invention is applicable to a sensor network system that collects information from a plurality of sensor nodes, and a communication path setting method.

100‧‧‧Sensor Network System

110‧‧‧ sensor node

112‧‧‧gate machine

114‧‧‧Center installation

116‧‧‧Base station

Claims (6)

A sensor network system is characterized in that: a complex sensor node corresponding to a smart meter; and a gateway machine collects data from a plurality of complex sensor nodes, and the sensor Node distribution data; and the central device receives data from the front gateway device and transmits data to the gateway device; the wireless communication between the sensor nodes and the sensor node and the front gate device is performed. The wireless communication between the gateway device and the pre-recording center device is performed through the payment communication network. The sensor network system as claimed in claim 1, wherein the pre-recorded sensor node is provided with: a ranking setting unit, which is a sensor node located at a position where wireless communication with the front gate device is possible, and rank 1 A correspondence is established, and a sensor node located at a position that can be wirelessly communicated with the rank n (n=1 or more) and has not yet been associated with the ranks 1 to n is associated with the rank n+1. The sensor network system as recited in claim 2, wherein the pre-recording setting unit, in the case of wireless communication with the higher-ranking sensor node, is in the wirelessly-sensing sensor node Correspond to the ranking of the next one of the top-ranked sensor nodes. The sensor network system as recited in claim 2 or 3, wherein the pre-recording ranking setting unit limits the ranking of the pre-recorded sensor node to the predetermined ranking. The sensor network system according to any one of claims 2 to 4, wherein the pre-sensor node further comprises: a data sending and receiving unit, which receives data from a sensor node ranked higher than the upper one. The material is broadcasted, and if there is no sensor node that ranks lower than the lower one within the range of wireless communication, the broadcast of the data is restricted. A communication path setting method, comprising: a complex sensor node corresponding to a smart meter; and a gateway machine collecting data from the complex sensor node, and the sensor node a distribution device; and a central device, in the sensor network system that receives data from the gateway device and transmits data to the gateway device, the sensor node and the sensor node and the gate Wireless communication is performed between the machines, and the gateway device and the central device perform wireless communication through the payment communication network; the pre-sensor node is a sensor located at a position where wireless communication with the front gate device is possible. The node, corresponding to the ranking 1, and located at a location that can be wirelessly communicated with the rank n (n=1 or more integers), and the sensor nodes that have not yet been associated with the ranks 1~n are associated with the rank n+1 .