JP6259622B2 - COMMUNICATION DEVICE, RADIO NETWORK SYSTEM, RADIO NETWORK CONTROL METHOD, AND RADIO NETWORK CONTROL PROGRAM - Google Patents

Description

  The present invention relates to a communication system in which a plurality of communication devices are connected by a wireless network.

  In recent years, a wireless communication terminal has been installed at each power consumer, and these are connected so as to be able to communicate with a collection server owned by the power company, and automatic meter reading is performed to periodically collect power meter reading data at each power consumer The system is being realized. In constructing such an automatic meter reading system, application of a so-called multi-hop wireless network system in which packets are sequentially transferred through the wireless communication terminal (node) is being studied.

  For example, a wireless data collection system has been proposed in which a tree-type network is configured with wireless communication terminals as nodes, meter-reading data is collected and integrated into a higher-level wireless communication device, and further transferred to the higher-level side ( Patent Document 1).

JP 2000-187793 A

  According to this technology, for example, if a tree is formed for each predetermined number of wireless communication terminals and meter reading data collected in the wireless communication device that is the root of each tree is collected, meter reading data is collected in a short time Will be able to.

  However, since wireless communication terminals perform data transmission / reception wirelessly, the radio wave environment may change due to weather, obstacles, etc., and data transmission / reception may not be possible. In addition, since the wireless communication terminal is installed in each electric power consumer, the number of data itself increases in an apartment house or a densely populated area, and the data may be complicated. In such a case, the wireless communication terminal secures a new route.

  Here, in a so-called proactive routing protocol in a multi-hop wireless network, each node transmits route update information to the entire network in response to a change in the network topology.

  Therefore, in a wireless network intended to collect meter reading data from the wireless communication terminals as described above, when the radio wave environment changes, route update information is transmitted from many wireless communication terminals at once, The data may be complicated and transmission / reception of meter reading data, which is the original purpose, may be hindered.

  Accordingly, an object of the present invention is to reduce the number of times route information is transmitted by a wireless communication terminal as much as possible in a multi-hop wireless network system.

Communication device according to one embodiment of the present invention is composed of a plurality of aggregation device and a plurality of communication devices, each of the plurality of communication devices, any one of the plurality of aggregation device, the multi-hop wireless communication The communication device of the connected wireless network system, which is a different aggregation device from the currently connected first aggregation device, and detects the second aggregation device that is currently connectable to the communication device An evaluation value indicating a degree of ease of connection between the detection means and a certain aggregation device, and an evaluation value calculation means for calculating an evaluation value indicating that the smaller the value is, the easier it is to connect, An evaluation value calculation unit calculates the evaluation values of the first aggregation device and the second aggregation device, and the evaluation value of the second aggregation device is equal to or greater than a predetermined ratio with respect to the evaluation value of the first aggregation device. Small value When the can, and a communication control means connected to the second aggregation device in place of the first aggregation device, wherein the evaluation value calculation means, wherein the transmitting the actual data to the plurality of aggregation device performance An evaluation value is calculated, and the communication control means sends the evaluation value calculating means to the first aggregation device after a fixed period of time from the connection to the first aggregation device to the stabilization of the path. When the evaluation value of the second aggregation device is smaller than the evaluation value of the first aggregation device by a predetermined ratio or more, the evaluation value of each of the second aggregation devices is calculated. The evaluation value of the second aggregation device is smaller than the evaluation value of the first aggregation device by a certain value or less than the evaluation value of the first aggregation device before connecting to the second aggregation device instead of the one aggregation device and the fixed period elapses. The second concentrator instead of the first concentrator. Characterized be tied about device.

A wireless network system according to another aspect of the present invention includes a plurality of aggregation devices and a plurality of communication devices, each of the plurality of communication devices being multi-hop with any one of the plurality of aggregation devices. A wireless network system connected by wireless communication, wherein the communication device is an aggregation device different from the first aggregation device currently connected, and a second aggregation device that is currently connectable to the communication device. An evaluation value calculating means for calculating an evaluation value indicating a degree of ease of connection to a certain aggregation device, an evaluation value indicating a degree of ease of connection as the value decreases; In a cycle, the evaluation value calculation means calculates the evaluation value of each of the first aggregation device and the second aggregation device, and the evaluation value of the second aggregation device corresponds to the evaluation value of the first aggregation device. Place If was smaller than the ratio, the first place to the aggregation device and a communication control means connected to the second aggregation device, wherein the evaluation value calculating means, actual data to the plurality of aggregation device The communication control means calculates the evaluation value to the evaluation value calculation means after a certain period of time until the route is stabilized after connecting to the first aggregation device. The evaluation values of the first aggregation device and the second aggregation device are calculated, and the evaluation value of the second aggregation device is a value smaller than a predetermined ratio with respect to the evaluation value of the first aggregation device. In this case, the evaluation value of the second aggregation device is connected to the second aggregation device instead of the first aggregation device, and the evaluation value of the second aggregation device is more than the evaluation value of the first aggregation device before the predetermined period has elapsed. Is less than a certain value, the first collection It characterized that you connected to the second aggregation device instead of the device.

A radio network control method according to another aspect of the present invention includes a plurality of aggregation devices and a plurality of communication devices, and each of the plurality of communication devices includes one of the plurality of aggregation devices and a plurality of aggregation devices. A wireless network control method used in the communication device of a wireless network system connected by hop wireless communication, wherein the wireless network control method is an aggregation device different from the currently connected first aggregation device, and is currently connected to the communication device An aggregation device detection step for detecting a possible second aggregation device, and an evaluation value indicating a degree of ease of connection with a certain aggregation device, and an evaluation value indicating that connection is easier as the value is smaller In the evaluation value calculating step, the evaluation value calculating step calculates the evaluation value of each of the first aggregation device and the second aggregation device, and the second aggregation device Worth, said the case was smaller than a predetermined percentage of the rated value of the first aggregation device, and a communication control step of connecting said second aggregation device in place of the first aggregation device, wherein In the evaluation value calculation step, the evaluation value is calculated from the actual data transmitted to the plurality of aggregation devices, and in the communication control step, a constant from the connection to the first aggregation device to the stabilization of the path. After the period has elapsed, in the evaluation value calculation step, the evaluation values of the first aggregation device and the second aggregation device are calculated, and the evaluation value of the second aggregation device is the evaluation value of the first aggregation device. When the value is smaller than a predetermined ratio with respect to the value, the evaluation value of the first aggregation device is connected to the second aggregation device instead of the first aggregation device, and before the predetermined period elapses. Than the above If the direction of evaluation value of the aggregation device is smaller than a predetermined value, characterized that you connected to the second aggregation device in place of the first aggregation device.

A wireless network control program according to another aspect of the present invention includes a plurality of aggregation devices and a plurality of communication devices, and each of the plurality of communication devices includes one of the plurality of aggregation devices, A wireless network control program used in the communication device of a wireless network system connected by hop wireless communication, which is an aggregation device different from the first aggregation device currently connected, and is currently connected to the communication device An evaluation value indicating the degree of ease of connection between the aggregation device detecting means for detecting a possible second aggregation device and a certain aggregation device, and an evaluation value indicating that the smaller the value is, the easier the connection is The evaluation value calculation means and the evaluation value calculation means cause the evaluation value calculation means to calculate the evaluation values of the first aggregation device and the second aggregation device at a predetermined cycle, and the second aggregation device When the evaluation value is a value smaller than a predetermined ratio with respect to the evaluation value of the first aggregation device, the computer functions as a communication control unit connected to the second aggregation device instead of the first aggregation device The evaluation value calculating means is for calculating the evaluation value based on actual results of transmitting data to the plurality of aggregation devices, and the communication control means is connected to the first aggregation device. Then, after a certain period of time until the route is stabilized, the evaluation value calculation means calculates the evaluation values of the first aggregation device and the second aggregation device, and the evaluation of the second aggregation device When the value is a value that is smaller than the evaluation value of the first aggregation device by a predetermined ratio or more, the value is connected to the second aggregation device instead of the first aggregation device, and before the predetermined period has elapsed. Is the first aggregation device If the direction of evaluation value of the second aggregation device than the evaluation value is smaller than a predetermined value, characterized that you connected to the second aggregation device in place of the first aggregation device.

According to the communication device, the wireless network system, the wireless network control method, and the wireless network control program having such a configuration, even if the second aggregation device is easier to connect than the first aggregation device, the second aggregation is performed. If the evaluation value of the device is not a value that is smaller than the evaluation value of the first aggregation device by a predetermined percentage or more, the second aggregation device is not connected instead of the first aggregation device. In other words, since the difference between the evaluation values, which is a condition for switching the connection, is determined as a ratio, those with smaller evaluation values can be switched even if the difference is small, and those with larger evaluation values are If the difference is not large, it cannot be switched. Since the larger the evaluation value, the harder the connection is. Therefore, when the evaluation values are high (the evaluation is low), that is, when the connection is difficult, the switching is difficult to occur. That is, when improvement in the communication quality of the wireless network cannot be expected, switching is difficult to occur, and as a result, transmission / reception of data associated with switching is difficult to occur. Therefore, it is possible to suppress the amount of data flowing through the network while maintaining the communication quality of the wireless network. Here, being easy to connect to the aggregation device means that a packet (data) transmitted from the communication device to the aggregation device is likely to reach the aggregation device.
In addition, the communication control unit calculates the evaluation value of each of the first aggregation device and the second aggregation device to the evaluation value calculation unit after a certain period of time has elapsed after connecting to the first aggregation device. If the evaluation value of the second aggregation device is smaller than the evaluation value of the first aggregation device by a predetermined ratio or more, the second aggregation device is connected to the second aggregation device instead of the first aggregation device. To do. According to this configuration, the evaluation value of the second aggregation device is smaller than the evaluation value of the first aggregation device by a predetermined ratio or more after a lapse of a certain period during which it can be estimated that the route to the first aggregation device is stable. It is possible to prevent immature pathways that are not stable from being fixed.

  The communication device further includes storage means for storing an identifier of an aggregation device that is a connection destination of the own device, and the storage means includes an identifier of the first aggregation device and an identifier of the second aggregation device. Is stored, the communication control means, when the aggregation device detection means detects a currently connectable third aggregation device, further adds the evaluation value calculation means to the third aggregation device. When the evaluation value of the third aggregation device is larger than the predetermined ratio with respect to the evaluation value of the second aggregation device, the second storage device stores the second evaluation value. It is preferable to maintain the identifier of the two aggregation devices.

  According to this configuration, when the evaluation value of the third aggregation device is larger than a predetermined ratio with respect to the evaluation value of the so-called spare second aggregation device, switching is not performed, that is, the third aggregation device is the second Since switching is not performed when the connection is not so easy as compared with the aggregation device, it is possible to suppress the amount of data flowing through the network without significantly changing the communication quality of the wireless network.

  Further, in the above communication device, the communication control means is configured such that the evaluation value of the third aggregation device is a value smaller than the predetermined ratio with respect to the evaluation value of the second aggregation device, and the first aggregation device If the value is equal to or greater than the evaluation value, it is preferable to store the identifier of the third aggregation device in the storage means instead of the identifier of the second aggregation device.

  According to this configuration, since the so-called spare second aggregation device is switched to the third aggregation device that is easily connected to a predetermined ratio or more, the communication quality of the wireless network can be further stabilized. In addition, since switching is not performed unless the communication quality of the wireless network is more stable, data transmission / reception associated with switching is less likely to occur, and as a result. It is possible to reduce the amount of data flowing through the network.

  Further, in the above communication device, when the communication control unit is connected to the second aggregation device instead of the first aggregation device, the communication control means transmits information indicating that the aggregation device has been replaced to the outside. Is preferred.

  In the above communication device, the communication control unit may replace the aggregation device when the identifier of the third aggregation device is stored in the storage unit instead of the identifier of the second aggregation device. It is preferable to transmit information indicating that to the outside.

  According to this configuration, since the information (data) is transmitted only when the aggregation device is switched, the amount of data flowing through the network can be suppressed.

  The multi-hop wireless network system according to the present invention can reduce the number of times route information is transmitted by a wireless communication terminal (communication device) as much as possible.

It is a figure which shows the usage example of the wireless network system for collecting meter-reading data from the terminal station of an electric power consumer. It is an example of the front view of the terminal station T. 1 is a diagram showing an outline of a wireless network system. It is a figure which shows the structural example of the functional block of a terminal station. It is a figure which shows the structural example of the functional block of gateway GW. It is a figure which shows the example of a structure and content of a GW information table. 5 is a diagram showing an example of the configuration and contents of a self-device information table 1820. FIG. (A) is a graph for demonstrating the evaluation value of gateway GW, (b) is a graph for demonstrating the evaluation value for determining switching. It is a figure for demonstrating the evaluation value for determining switching. It is a flowchart of an evaluation value update process. It is a flowchart of a gateway determination process. It is a flowchart of GW detection processing. It is a figure for demonstrating the data transmitted / received in a wireless network. It is a figure for demonstrating the data transmitted / received in a wireless network.

<Embodiment>
The wireless network system of the embodiment is a multi-hop wireless network, and is a system for collecting meter reading data from each power consumer.

  FIG. 1 is a diagram illustrating a usage example of the wireless network system according to the embodiment. This wireless network system includes power consumers H1, H2,..., H12 (collectively referred to as power consumer H), and a terminal station T1 that is a power meter installed in each power consumer H. , T2,..., T12 (when collectively referred to as a terminal station T), gateways GWa, GWb, and GWc (when collectively referred to as gateway GW), a network 2, and a server device 1. In addition, the number of the electric power consumer H, the terminal station T, the gateway GW, and the server apparatus 1 is not restricted to these numbers.

  The network 2 is a network managed by a network operating company such as an electric power company, and may be wired or wireless. The gateway GW is connected to the server device 1 that is provided in, for example, a main utility pole and managed by an electric power company or the like via the network 2.

  The terminal station T constitutes a node of a network using multihop and belongs to any gateway GW. The terminal station T has a function as an integrated watt-hour meter, and each meter reading data is sequentially transferred to the adjacent terminal station T and collected at the gateway GW to which the own apparatus belongs. The meter reading data collected in each gateway GW is transmitted to the server device 1 via the network 2. The terminal station T performs communication according to a wireless LAN (Local Area Network) standard, and performs one-to-one communication in an ad hoc mode as indicated by signals A1 to 4 and the like. Each gateway GW collects meter reading data of about several hundred terminal stations T.

  FIG. 2 is an example of a front view of the terminal station T. The terminal station T is configured by arranging a terminal block 6, a load switch 3000, a power meter 2000, and a communication device 1000 to which each distribution line in the home of a power consumer is connected. The power meter 2000 reads the accumulated power amount every predetermined period, for example, every 5 minutes. The meter reading data is transmitted every 30 minutes by the communication apparatus 1000 toward the gateway GW to which the own apparatus belongs. The load switch 3000 performs an opening / closing operation in accordance with control data transmitted from the server device 1.

  Here, FIG. 3 shows an outline of the network using the multi-hop of the embodiment. A double circle indicates the gateway GW, and an identifier “GWa” or the like of the gateway GW is described inside the circle. A single circle indicates the terminal station T, and an identifier “T1” or the like of the terminal station T is described inside the circle. A broken line connecting the circles indicates that the gateways GW or the terminal stations T indicated by circles at both ends thereof detect (learn) each other's existence.

  The server device 1 and the gateway GW are connected by a network (communication line) 2, and the gateway GW and each terminal station are connected by multi-hop. In the network of the embodiment, the number of hops is at most several tens, preferably 10 hops or less.

  The network of the embodiment is generated by, for example, OLSR (Optimized Link State Routing) which is one of so-called proactive routing protocols in a multi-hop wireless network. As for the route between the gateway GW and each terminal station T, each device (gateway GW, terminal station T) periodically transmits and receives a message for exchanging route information while transmitting the presence of the device itself. Thus, each device constructs autonomously. Each gateway GW and each terminal station T is a routing table (route table) which is topology information of the entire network, for example, a terminal station T in the learned network and an adjacent network for transmitting data to the terminal station T. The terminal station T that is the transmission destination is stored in association with it.

  Since each device autonomously constructs an optimum route according to changes in surrounding radio wave conditions, etc., the upstream route from the terminal station T to the gateway GW and the downstream route from the gateway GW to the terminal station T The route may be different.

  The meter reading data is transmitted on the upstream route toward the gateway GW to which the terminal station T belongs. For example, in FIG. 3, the hatched terminal T with the identifier “T8” (hereinafter referred to as “terminal T8”) is transferred to the gateway GW with the identifier “GWa” (hereinafter referred to as “gateway GWa”). The upstream route is indicated by a solid arrow facing the gateway GW. Specifically, the meter reading data transmitted from the terminal station T8 reaches the gateway GWa via the terminal station T6. FIG. 13A shows an example of a packet transmitted from the terminal station T8 to the terminal station T6, which is a higher adjacent transmission destination, in order to transmit the meter reading data to the gateway GWa. This packet includes the destination “T6-Addr” of the terminal station T6 as the adjacent destination, the destination “GWa-Addr” of the terminal station T8 as the final destination, “meter reading data” as the data type, and the meter reading data of the own apparatus. The terminal station T6 that has received the meter reading data packet from the terminal station T8 transfers the received packet to the destination on the path to the final destination “GWa-Addr”. In the case of FIG. 3, the terminal station T <b> 6 transfers the received packet to “GWa-Addr”, but transfers the packet to the terminal station T when passing through another terminal station T.

  In the embodiment, the destination of the terminal station T is a MAC (Media Access Control) address, and the gateway GW is an IP (Internet Protocol) address. Further, in the packet example shown in FIGS. 13 and 14, only item data necessary for explanation is described.

  Further, when transmitting control data to the terminal station T8, the server device 1 passes control data (command) to the gateway GWa to which the terminal station T belongs, and requests transmission to the terminal station T8. The control data is transmitted on the down route indicated by the solid arrow route toward the terminal station T8 in FIG. Specifically, the control data transmitted by the gateway GWa reaches the gateway GWa via the terminal station T1, the terminal station T3, and the terminal station T5.

  In order to transmit to the terminal station T8, the gateway GWa transmits a control data packet to the terminal station T1, which is an adjacent transmission destination. An example of a packet that the gateway GWa transmits to the terminal station T1 is shown in FIG. This packet includes the destination “T1-Addr” of the terminal station T1 as the adjacent destination, the “control data” as the data type, the destination “T8-Addr” of the gateway GWa as the final destination, and the control data. The terminal station T1 that has received the control data packet from the gateway GWa transfers the packet to the terminal station T3 that is an adjacent transmission destination to the final destination “T8-Addr”.

  Here, since communication between the terminal stations T is performed wirelessly, it is considered that the radio wave environment changes and communication cannot be performed. For example, the radio wave environment changes due to various factors such as worsening weather, increased traffic of large vehicles, and construction of large buildings. Therefore, even if the route is once determined, the communication device 1000 of the terminal station T according to the embodiment is currently used to transmit meter-reading data to the server device 1 in order to quickly respond to changes in the radio wave environment. A route other than the existing route is secured as a backup route (sub route). That is, a gateway GW other than the gateway GW to which it currently belongs (hereinafter referred to as “main gateway GW”) is secured as a spare gateway GW (hereinafter referred to as “sub-gateway GW”). For example, the terminal station T8 in FIG. 3 secures “GWb” as the sub-gateway GW, and constructs a route to the GWb (see the route indicated by the dashed arrow). Since the terminal station T knows the network status by receiving messages from other terminal stations T and the gateway GW, the route to the gateway GWc other than the main gateway GW and the sub-gateway GW is also available. It is constructed (see the route indicated by the one-dot chain line arrow).

  Each terminal station T of the wireless network system of the embodiment learns a plurality of gateways GW, and dynamically switches to a gateway GW capable of more stable transmission / reception, thereby constructing a more stable network. When the gateway GW is switched, data indicating the gateway GW to which the gateway GW is switched, that is, data indicating which gateway GW the current apparatus belongs to (location information data) is transmitted to the server apparatus 1. This is so that the server apparatus 1 can transmit control data to the terminal station T.

  Further, data indicating which gateway GW is secured as the sub-gateway GW is also transmitted. That is, the server device 1 is also notified when the sub-gateway GW is changed. This is because the server device 1 is used as a backup destination when communication toward the terminal station T via the main gateway GW fails.

  FIG. 14A shows an example of a packet for the terminal station T8 to transmit position information data indicating the main gateway GW and the sub-gateway GW to the server device 1. In this packet, the destination “T6-Addr” of the terminal station T6 as the destination, “position information” as the data type, the destination “T8-Addr” of the own apparatus as the transmission source, the identifier “GWa” of the main gateway GW, the sub-gateway The GW identifier “GWb” is included. This position information data is transmitted to the server device 1 via the main gateway GW.

  In a multi-hop wireless network, a situation in which a large number of pieces of position information data are transmitted to the server device 1 at a time may occur due to a change in communication environment due to weather or a temporary failure. In this case, traffic due to a large amount of position information data may increase and communication may not be performed as expected, and processing of the server device 1 may not be able to catch up.

  Therefore, in the wireless network system of the embodiment, the gateway GW switching logic is used so that the number of times the terminal station T switches the gateway GW can be reduced and a more stable network can be constructed.

  Hereinafter, an embodiment according to the present invention will be described with reference to the drawings.

<Configuration>
FIG. 4 is a diagram illustrating a configuration example of functional blocks of the terminal station T. The terminal station T includes a communication device 1000, a power meter 2000, and a load switch 3000. Dashed arrows indicate that some terminal stations T communicate with the gateway GW (aggregation device).

  The communication apparatus 1000 includes a wireless communication control unit 1100, a wireless communication unit 1200, a timer 1300, an in-flight communication control unit 1400, an interface 1410, an interface 1420, an external interface 1500, an input unit 1510, a GW determination unit 1600, an evaluation value calculation unit 1700, A link information storage unit 1800 (storage unit) and an electric energy information storage unit 1900 are provided.

  The wireless communication control unit 1100 includes a GW detection unit 1110 (aggregation device detection unit), and has a function of controlling wireless communication by controlling each functional unit. For example, the power amount stored in the power amount information storage unit 1900 is read every predetermined period, for example, every 30 minutes, and a packet destined for the gateway GW to which the terminal station T belongs is transmitted to the wireless communication unit 1200. Etc. The detection that the predetermined period has elapsed is detected by an interrupt from the timer 1300.

  The GW detection unit 1110 has a function of detecting information such as addition, deletion, or failure of the gateway GW from data received via the wireless communication unit 1200. The GW detection unit 1110 receives a message including information on the gateway GW from another terminal station T, analyzes the received message, and detects addition, deletion, failure, or the like of the gateway GW. This message is broadcast by each gateway GW and each terminal station T in a predetermined cycle. Note that the server device 1 may transmit information such as addition, deletion, and failure of the gateway GW via the gateway GW.

  Specifically, when a gateway GW is newly added, the added gateway GW transmits (for example, floods) a message including information on the own device. Accordingly, the GW detection unit 1110 detects that the gateway GW has been added when the received message includes information on a new gateway GW. Further, the gateway GW does not transmit a message when it is not operated due to being removed or stopped. Therefore, when the GW detection unit 1110 does not receive a message from the gateway GW for a certain period, it determines that the gateway GW has been deleted. Further, when the gateway GW detects a failure of its own device, the gateway GW transmits a message including that fact. Therefore, when the GW detection unit 1110 receives a message including a failure message, the GW detection unit 1110 detects that the gateway GW has failed.

  FIG. 14B shows an example of a message transmitted to the surroundings by the terminal station T8 of FIG. This message (packet) includes all destinations (broadcast addresses) as destinations, a destination “T8-Addr” of the own device as a transmission source, a list of identifiers of all gateways GW learned by the own device as learning GW information, As the adjacent node information, a list of identifiers (destination addresses) of adjacent terminal stations T (adjacent terminal stations), as the other station information, the identifiers of the terminal stations T learned by the own device and adjacent transmissions to the terminal stations T The first (next hop) and the like are included. When the terminal station T that has received this message includes an identifier of the gateway GW that the device itself has not learned in the “list of identifiers of all gateways GW that the device itself has learned” in the message, It can be detected that a new gateway GW has been added, and the terminal station T that is the transmission source of the message can be obtained as an adjacent transmission destination.

  When addition, deletion, failure, or the like of the gateway GW is detected, the GW detection unit 1110 stores it in the link information storage unit 1800.

  The wireless communication unit 1200 has a function of communicating with another terminal station T (“terminal station T ′” in FIG. 4) or the gateway GW in an ad hoc mode according to the wireless LAN standard.

  The timer 1300 has a function of notifying the wireless communication control unit 1100 and the in-flight communication control unit 1400 of the time and also interrupting at a predetermined cycle. For example, the wireless communication control unit 1100 is interrupted every 30 minutes. For example, an in-flight communication control unit 1400 is interrupted every 5 minutes. The wireless communication control unit 1100 reads and transmits the meter reading data for 30 minutes from the power amount information storage unit 1900 at the timing of interruption, and the in-flight communication control unit 1400 receives the received power amount for 5 minutes from the power meter 2000 at the timing of interruption. And stored in the power amount information storage unit 1900.

  The interface 1410 is an interface that receives meter reading data from the power meter 2000, and the interface 1420 is an interface that transmits control data to the load switch 3000.

  The in-flight communication control unit 1400 has a function of controlling communication with the power meter 2000 and the load switch 3000 via the interface 1410 and the interface 1420. The in-flight communication control unit 1400 has a function of periodically acquiring the received power amount from the power meter 2000 and storing the received power amount in the power amount information storage unit 1900.

  The external interface 1500 is an interface connected to an external setting tool or the like, and is used for setting initial values and the like when the terminal station T is initially set.

  The input unit 1510 has a function of accepting a user operation and storing data in the link information storage unit 1800 and the electric energy information storage unit 1900 or rewriting the stored data in accordance with the user operation. .

  The GW determination unit 1600 has a function of determining the main gateway GW and the sub-gateway GW. In the embodiment, the current primary gateway GW, the current secondary gateway GW, and the newly detected gateway GW, that is, the gateway GW that may be either the primary gateway GW or the secondary gateway GW (hereinafter, “ The main gateway GW and the sub-gateway GW are determined from the three gateways GW. There may be a plurality of candidate gateways GW. The method for determining the gateway GW will be described in the section <Method for determining the gateway GW>.

  The evaluation value calculation unit 1700 has a function of calculating the evaluation value of the gateway GW at the request of the wireless communication control unit 1100. The wireless communication control unit 1100 receives an evaluation value at a predetermined timing such as when a message is received, when a data communication arrival response is received, when a data communication failure is detected, when a loop route is detected, etc. The calculation unit 1700 is requested to calculate and update the evaluation value of the gateway GW. At this time, the wireless communication control unit 1100 stores information necessary for calculating an evaluation value such as received signal strength when a message is received in the link information storage unit 1800.

  The evaluation value refers to a value indicating the ease of connection to the gateway GW, and the smaller the value, the easier the connection. The method for calculating the evaluation value will be described in the section <Method for determining gateway GW>.

  The link information storage unit 1800 has a function of storing information necessary for data transmission / reception such as topology information of the entire network as shown in FIG. Furthermore, it is assumed that the link information storage unit 1800 stores information necessary for calculating evaluation values of the main gateway GW, the sub gateway GW, and the candidate gateway GW.

  The power amount information storage unit 1900 has a function of storing the power amount acquired from the power meter 2000 by the in-flight communication control unit 1400.

  FIG. 5 is a diagram illustrating a configuration example of functional blocks of the gateway GW. The gateway GW includes a wireless communication control unit 4100, a wireless communication unit 1200, a timer 1300, an external interface 1500, an input unit 1510, an external communication control unit 4000, a link information storage unit 1800, and a meter reading data storage unit 1850.

  The wireless communication control unit 4100 has a function of controlling each functional unit to control wireless communication. The meter reading data received from the terminal station T is stored in the meter reading data storage unit 1850. The wireless communication control unit 4100 reads meter-reading data stored in the meter-reading data storage unit 1850 at a predetermined timing, transmits the data to the server device 1 via the external communication control unit 4000, and the external communication control unit 4000. The packet from the server device 1 received via the wireless communication unit 1200 is transmitted to the terminal station T via the wireless communication unit 1200.

  The wireless communication unit 1200, the timer 1300, the external interface 1500, the input unit 1510, and the link information storage unit 1800 are the wireless communication control unit 1100, the wireless communication unit 1200, the timer 1300, the external interface 1500, the input unit 1510, and the link of the communication device 1000. The information storage unit 1800 has the same function.

  The external communication control unit 4000 has a function of communicating with the server device 1.

  The meter-reading data storage unit 1850 has a function of storing meter-reading data transmitted from the terminal station T belonging to the gateway GW that is its own device.

  Each of the communication apparatus 1000 and the gateway GW of the embodiment can be configured using, for example, a computer, and software that programs a gateway GW determination method and the like stored in a storage unit (not shown) such as a hard disk, When executed by the CPU, the wireless communication control unit 1100 and the like described above are functionally configured in the computer. A part of the functional unit may be realized by hardware.

<Data>
Hereinafter, main data used in the communication apparatus 1000 will be described with reference to FIGS. 6 and 7.

  FIG. 6 is a diagram showing an example of the configuration and contents of the GW information table 1810. The GW information table 1810 is stored in the link information storage unit 1800.

  The GW information table 1810 includes a GW type 1811, a GW-ID 1812, a destination 1813, and an evaluation value 1814.

  The GW type 1811 indicates the type of the gateway GW. “Main GW” means the main gateway GW, “Sub GW” means the sub-gateway GW, and “Candidate GW” means the candidate gateway GW.

  The GW-ID 1812 indicates an identifier that identifies the type of gateway GW indicated by the GW type 1811. For example, since “GWa” is set as the GW-ID 1812 whose GW type 1811 is “main GW”, the gateway GWa whose identifier is “GWa” is currently the main gateway GW.

  A destination 1813 indicates a destination of an adjacent terminal station T that is a direct transmission destination of data when data is transmitted to the gateway GW indicated by the GW-ID 1812.

  The evaluation value 1814 indicates the evaluation value of the gateway GW indicated by the GW-ID 1812.

  FIG. 7 is a diagram showing an example of the configuration and contents of the own device information table 1820. The own device information table 1820 is stored in the link information storage unit 1800.

  The own apparatus information table 1820 has an item 1821 and contents 1822.

  An item 1821 indicates an item of information regarding the own device. “Own device address” indicates a destination address of the own device.

  Content 1822 indicates the content of the item indicated by the item 1821. For example, since “T8-Addr” is set as the content 1822 of the “own device address” in the item 1821, the destination of the terminal station T storing the own device information table 1820 is “T8-Addr”. It will be. Therefore, the packet in which “T8-Addr” is set as the destination is determined to be a packet addressed to the own apparatus. In the embodiment, the own device address is a MAC address.

<Determination method of gateway GW>
Here, the gateway GW determination method performed by the communication apparatus 1000 will be described with reference to FIGS. 8 and 9.

  The communication apparatus 1000 calculates an evaluation value of each gateway GW registered in the GW information table 1810 (see FIG. 6) at a predetermined cycle, for example, every 10 minutes. Basically, the gateway GW having the highest evaluation is calculated. Is the main gateway GW, and the gateway GW having the next highest evaluation is the sub-gateway GW.

  In the embodiment, the evaluation value is calculated from a record of actually transmitting data to each gateway GW. For example, it is calculated based on the number of successful communications, the adjacent connection probability, the number of hops to the gateway GW, the electric field strength of the radio wave from the terminal station T, which is the direct transmission destination of data, and the like. Data necessary to calculate these evaluation values is stored in the link information storage unit 1800. The evaluation value is higher as the numerical value is smaller. Note that the data for calculating the evaluation value is not limited to these, and it is only necessary to be able to calculate the evaluation value indicating the ease of connection.

  Here, the gateway GW determination method will be described using the GW information table 1810 (see FIG. 6) as an example. FIG. 8A is a bar graph of evaluation values of each gateway GW. The vertical axis represents the evaluation value. The evaluation value of the gateway GWa that is the main gateway GW is “200” points, the evaluation value of the gateway GWb that is the sub-gateway GW is “400” points, and the evaluation value of the gateway GWc of the candidate gateway GW is “300” points.

  Considering the ease of connection with the gateway GW, it is conceivable that the gateway GWc having the next highest evaluation is the sub-gateway GW without changing the gateway GWa of the highest evaluation main gateway GW. However, in the embodiment, since the gateway GWc has a lower evaluation value (good evaluation) by “100” points than the gateway GWb, the secondary gateway GW is not switched.

  In the embodiment, only when the evaluation value of the gateway GWc is lower than the evaluation value of the gateway GWb by a certain proportion of the evaluation value of the gateway GWb (switching evaluation value adjustment rate), that is, the switching evaluation value adjustment rate. Switch if the rating is higher than min. That is, switching is not performed when there is a difference greater than a predetermined value, but switching is performed when there is a difference greater than a certain ratio (switching evaluation value adjustment rate) of the current gateway GW evaluation values. In addition, this difference must be a minimum difference (minimum difference threshold) necessary for switching, for example, “10” points or more.

Specifically, the gateway GW is switched when the following expressions (1) and (2) are satisfied. “Target GW” indicates a gateway GW that is a target for determining whether or not to switch, and in the embodiment, indicates a main gateway GW or a sub-gateway GW.
(Evaluation value of target GW−Evaluation value of candidate GW)>
(Evaluation value of target GW × switching evaluation value adjustment rate) (1)
(Evaluation value of target GW−Evaluation value of candidate GW)> Minimum difference threshold value (2)

  Therefore, for example, when the switching evaluation value adjustment rate is 40% and the minimum difference threshold is 10 points, the evaluation value of the gateway GWb is “400”, so the evaluation value of the gateway GWc exceeds the difference “160” points. If the evaluation value is lower than the gateway GWc, the gateway GWc is set as the secondary gateway GW. As shown in FIG. 8B, when the difference is “161” points or more, that is, when the evaluation value of the gateway GWc is “239” points or less, the sub-gateway GW is switched.

  Further, since the evaluation value of the gateway GWa of the main gateway GW is “200” points, the difference is “80” points, and when the evaluation value of the gateway GWc is “119” points or less, the main gateway GW is switched. It will be.

  Thus, when there is a difference greater than a predetermined value with respect to the evaluation value of the main gateway GW or the sub-gateway GW, switching is not performed, but the evaluation value of the current gateway GW is constant. The reason why the switching is not performed if the evaluation is not better than the above ratio is that a significant improvement in the quality of the wireless network cannot be expected when the low evaluation gateways GW are replaced. On the other hand, when switching is performed when there is a difference greater than a predetermined value, even if the gateway GWs are low in evaluation, they are switched if there is a difference greater than a predetermined value. Even though the quality remains low, data transmission associated with switching is performed.

  In other words, the communication apparatus 1000 according to the embodiment does not need to transmit data that must be transmitted along with the switching without switching the gateway GW when a significant quality improvement of the wireless network is not recognized. As a result, the maintenance of the quality of the wireless network and the securing of resources associated with the suppression of communication traffic, for example the securing of the necessary bandwidth, are realized at the same time. Therefore, the communication apparatus 1000 according to the embodiment can flexibly cope with various field environments and can be applied to various field environments.

FIG. 9 shows a correspondence table 9000 between the evaluation value of the main gateway GW or the sub-gateway GW and the evaluation value of the candidate gateway GW. The “main / sub evaluation value” indicates an evaluation value of the main gateway GW or the sub gateway GW, that is, an evaluation value of the target gateway GW. “Switching value” indicates the upper limit of the evaluation value of the candidate gateway GW when the main gateway GW or the sub-gateway GW is switched to the candidate gateway GW. That is, switching is performed when the evaluation value of the candidate gateway GW is equal to or lower than the switching value. The switching value is calculated using the following equation (3).
Switching value = evaluation value of target GW− (evaluation value of target GW × switching evaluation value adjustment rate)
... (3)
The “difference” in the correspondence table 9000 indicates the difference between the “main / sub evaluation value” and the “switching value”.

  As the correspondence table 9000 indicates, the “difference” increases as the evaluation value of the main gateway GW or the sub-gateway GW increases (the evaluation decreases). That is, switching is difficult to occur. On the other hand, the lower the evaluation value of the main gateway GW or the sub-gateway GW (the higher the evaluation), the smaller the “difference” and the easier the switching occurs. That is, it can be seen that switching is likely to occur higher when the quality of the wireless network is high, but switching is less likely to occur when the quality of the wireless network is low.

  In the embodiment, after the route to the gateway GW is determined (estimated), for example, after the route is used for 24 hours, the gateway GW switching process at a predetermined cycle as described above is started. To do. For a certain period of time until the route to the main gateway GW is stabilized, for example, when a gateway GW having an evaluation value lower (high evaluation) by “10” points or more than the evaluation value of the main gateway GW is found, Let the gateway GW be the main gateway GW. When the main gateway GW is switched, 24 hours are again measured from the beginning.

  When the gateway GW is switched using the ratio of the evaluation values as in this embodiment, switching is less likely to occur when there is a certain difference (for example, “10” points) in the evaluation values. . Therefore, after the path to the main gateway GW can be estimated to be stable, by performing switching using the ratio of the evaluation values as described above, an immature path that is not stable is prevented from being fixed. It is.

  Immediately after starting the terminal station T, the detected gateways GW are sequentially selected to perform communication. If the communication is successful, the evaluation of the gateway GW is increased. Therefore, even if the gateway GW that is originally not stable is selected, the evaluation of the gateway GW is increased due to the successful communication. This is because the GW is fixed. That is, immediately after activation, the gateways GW are selected in order to prevent the gateway GW from being fixed, and appropriate evaluation of each gateway GW is performed.

<Operation>
Hereinafter, the operation of the communication apparatus 1000 of the terminal station T will be described with reference to FIGS.

  FIG. 10 is a flowchart showing the evaluation value update process.

  When the wireless communication control unit 1100 receives a message via the wireless communication unit 1200 (step S40: Yes), the terminal station T that is the transmission source of the received message is an adjacent terminal station T to any gateway GW. The evaluation value calculation unit 1700 is requested to calculate and update the evaluation value of the gateway GW. At this time, the wireless communication control unit 1100 stores information such as the electric field strength of the message in the link information storage unit 1800.

  Upon receiving the request, the evaluation value calculation unit 1700 reads information necessary for calculating the evaluation value from the link information storage unit 1800, and calculates the evaluation value of the gateway GW instructed from the wireless communication control unit 1100. The evaluation value calculation unit 1700 that has calculated the evaluation value sets the calculated evaluation value as the evaluation value 1814 of the instructed gateway GW in the GW information table 1810 (see FIG. 6) stored in the link information storage unit 1800. In step S44, the wireless communication control unit 1100 is notified that the evaluation value has been calculated and updated.

  Receiving that the evaluation value has been calculated, the wireless communication control unit 1100 returns to step S40.

  When the wireless communication control unit 1100 receives a data communication arrival response packet (step S41: Yes), the terminal station T that is the transmission source of the received packet is an adjacent terminal station T to any gateway GW. The evaluation value calculation unit 1700 is requested to calculate and update the evaluation value of the gateway GW. At this time, the wireless communication control unit 1100 adds 1 to the number of successful communication records stored in the link information storage unit 1800. In addition, when the wireless communication control unit 1100 transmits a packet toward a gateway GW but does not receive a packet arrival response packet for a predetermined period (step S42: Yes), the evaluation value of the gateway GW The evaluation value calculation unit 1700 is requested to calculate and update. At this time, the wireless communication control unit 1100 subtracts 1 from the number of successful communication records stored in the link information storage unit 1800.

  Further, when the wireless communication control unit 1100 detects a loop route or the like on a route to a gateway GW (step S43: Yes), the wireless communication control unit 1100 requests the evaluation value calculation unit 1700 to calculate and update the evaluation value of the gateway GW. To do. At this time, the wireless communication control unit 1100 reduces the quality of the route stored in the link information storage unit 1800.

  Next, FIG. 11 is a flowchart showing the gateway GW determination process. The gateway GW determination process is a process for determining whether to switch the current main gateway GW or sub-gateway GW to the candidate gateway GW.

  When the wireless communication control unit 1100 detects the evaluation timing of the gateway GW by an interrupt from the timer 1300 (step S10: Yes), the wireless communication control unit 1100 determines whether to switch the primary gateway GW or the secondary gateway GW to the GW determination unit 1600. Ask for a decision.

  Upon receiving the request, the GW determination unit 1600 determines whether to switch the gateway GW as described in <Gateway GW Determination Method>. Specifically, the GW determination unit 1600 first reads the value set as the evaluation value 1814 in the record in which “main GW” is set as the GW type 1811 as the evaluation value of the main gateway GW. Further, the value set as the evaluation value 1814 in the record in which “candidate GW” is set as the GW type 1811 is read as the evaluation value of the candidate gateway GW.

  Then, when the evaluation value of the candidate gateway GW is smaller than the evaluation value of the main gateway GW (when the evaluation of the candidate gateway GW is higher) (step S12: Yes), the GW determination unit 1600 determines that the above equation (3) Is used to calculate the switching value of the main gateway GW (step S13). When the evaluation value of the candidate gateway GW is smaller than the calculated switching value (step S14: Yes), the GW determination unit 1600 switches the main gateway GW to the candidate gateway GW (step S15). Specifically, the data set as the GW-ID 1812, the destination 1813, and the evaluation value 1814 in the record in which “main GW” is set as the GW type 1811 of the GW information table 1810, and “candidate” as the GW type 1811 The data set as the GW-ID 1812, the destination 1813, and the evaluation value 1814 are exchanged in the record in which “GW” is set. Then, the GW determination unit 1600 notifies the wireless communication control unit 1100 that the main gateway GW and the candidate gateway GW have been switched.

  Receiving the notification that the main gateway GW has been switched, the wireless communication control unit 1100 creates a packet (see FIG. 14A) for notifying its own location information and transmits it to the server device 1 ( Step S16), the process is terminated.

  When the evaluation value of the candidate gateway GW is greater than or equal to the evaluation value of the main gateway GW in step S12 (step S12: No), or when the evaluation value of the candidate gateway GW is greater than or equal to the switching value of the main gateway GW (step S14) Step S14: No), the GW determination unit 1600 uses, as the evaluation value of the secondary gateway GW, the value set as the evaluation value 1814 in the record in which “secondary GW” is set as the GW type 1811 from the GW information table 1810. read out.

  Then, when the evaluation value of the candidate gateway GW is smaller than the evaluation value of the sub-gateway GW (when the evaluation of the candidate gateway GW is higher) (step S17: Yes), the GW determination unit 1600 determines the above equation (3). Is used to calculate the switching value of the sub-gateway GW (step S18). When the evaluation value of the candidate gateway GW is greater than or equal to the calculated switching value (step S19: No), the GW determination unit 1600 ends the process. On the other hand, when the evaluation value of the candidate gateway GW is smaller than the calculated switching value (step S19: Yes), the GW determination unit 1600 switches the secondary gateway GW to the candidate gateway GW (step S20). Specifically, the data set as the GW-ID 1812, the destination 1813, and the evaluation value 1814 in the record in which “secondary GW” is set as the GW type 1811 of the GW information table 1810, and “candidate” as the GW type 1811 The data set as the GW-ID 1812, the destination 1813, and the evaluation value 1814 are exchanged in the record in which “GW” is set. Then, the GW determination unit 1600 notifies the wireless communication control unit 1100 that the sub gateway GW and the candidate gateway GW have been switched.

  Receiving the notification that the sub-gateway GW has been switched, the wireless communication control unit 1100 creates a packet (see FIG. 14A) for notifying its own location information and transmits it to the server device 1 ( Step S21), the process is terminated.

  Next, the GW detection process will be described with reference to FIG. This GW detection process is a process performed by the GW detection unit 1110.

  Of the data received via the wireless communication unit 1200, the wireless communication control unit 1100 passes a message (see FIG. 14B) periodically transmitted by the peripheral terminal station T to the GW detection unit 1110.

  When the GW detecting unit 1110 receives a message periodically transmitted from a peripheral terminal station T from the wireless communication control unit 1100, the GW detecting unit 1110 analyzes the message, and the terminal station T includes information on a new gateway GW. Determines that a new gateway GW has been detected (step S30: Yes), and adds the gateway GW to the GW information table 1810 as a candidate gateway GW (step S31). Specifically, the identifier of the detected gateway GW is set as the GW-ID 1812 of the record in which “candidate GW” is set as the GW type 1811, and the destination of the terminal station T that transmitted the message is set as the destination 1813. .

  In addition, when the gateway GW is deleted or a failure is detected, the GW detection unit 1110 deletes the corresponding gateway GW from the GW information table 1810.

  In the embodiment, the switching of the gateway GW (aggregation device) in the wireless network system using the wireless LAN has been described. However, the embodiment is not limited to the wireless LAN, and may be a wireless network using a communication method of another standard. Alternatively, a data communication service such as PHS (Personal Handyphone System) may be used. Further, a part of the network system may be wired or a part may be connected wirelessly.

  In order to express the present invention, the present invention has been properly and fully described through the embodiments with reference to the drawings. However, those skilled in the art can easily change and / or improve the above-described embodiments. It should be recognized that this is possible. Therefore, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not covered by the claims. To be construed as inclusive.

GW gateway (aggregation device)
T terminal station H power customer 1 server device 2 network 1000 communication device 1100 wireless communication control unit 1110 GW detection unit (aggregation device detection means)
1200 Wireless communication unit 1300 Timer 1400 In-flight communication control unit 1500 External interface 1600 GW determination unit 1700 Evaluation value calculation unit 1800 Link information storage unit (storage means)
1900 Electric energy information storage unit 2000 Wattmeter 3000 Load switch 4000 External communication control unit

Claims (8)

The communication device includes a plurality of aggregation devices and a plurality of communication devices, and each of the plurality of communication devices is the communication device of the wireless network system connected to any one of the plurality of aggregation devices by multi-hop wireless communication. There,
Aggregation device detection means for detecting a second aggregation device that is a different aggregation device from the currently connected first aggregation device and is currently connectable to the communication device;
An evaluation value indicating a degree of ease of connection with a certain aggregation device, an evaluation value calculating means for calculating an evaluation value indicating that the connection is easier as the value is smaller;
In a predetermined cycle, the evaluation value calculation unit calculates the evaluation values of the first aggregation device and the second aggregation device, and the evaluation value of the second aggregation device becomes the evaluation value of the first aggregation device. If the value is smaller than a predetermined ratio, a communication control means for connecting to the second aggregation device instead of the first aggregation device ,
The evaluation value calculation means is for calculating the evaluation value from a record of actually transmitting data to the plurality of aggregation devices,
The communication control means includes
After the elapse of a certain period until the path is stabilized after connecting with the first aggregation device, the evaluation value calculation means calculates the evaluation values of the first aggregation device and the second aggregation device, If the evaluation value of the second aggregation device is a value smaller than a predetermined ratio with respect to the evaluation value of the first aggregation device, connect to the second aggregation device instead of the first aggregation device,
If the evaluation value of the second aggregation device is smaller than the evaluation value of the first aggregation device by a certain value or more before the fixed period elapses, the second aggregation is substituted for the first aggregation device. communication device characterized that you connected device. Storage means for storing the identifier of the aggregation device that is the connection destination of the device itself,
In the case where the storage means stores the identifier of the first aggregation device and the identifier of the second aggregation device,
The communication control unit causes the evaluation value calculation unit to further calculate an evaluation value of the third aggregation device when the aggregation device detection unit detects a third aggregation device that is currently connectable. When the evaluation value of the three aggregation devices is larger than the predetermined ratio with respect to the evaluation value of the second aggregation device, the identifier of the second aggregation device stored in the storage means is maintained. The communication apparatus according to claim 1. The communication control means is such that the evaluation value of the third aggregation device is smaller than the evaluation value of the second aggregation device by a value equal to or greater than the predetermined ratio and is equal to or greater than the evaluation value of the first aggregation device. In this case, the communication device according to claim 2, wherein an identifier of the third aggregation device is stored in the storage unit instead of the identifier of the second aggregation device. The communication control means, when connected to the second aggregation device instead of the first aggregation device, transmits information indicating that the aggregation device has been replaced to the outside. The communication device described. When the communication control unit stores the identifier of the third aggregation device in the storage unit instead of the identifier of the second aggregation device, the communication control unit transmits information indicating that the aggregation device has been replaced to the outside. The communication apparatus according to claim 3. A plurality of aggregation devices and a plurality of communication devices, each of the plurality of communication devices is a wireless network system connected by multi-hop wireless communication with any one of the plurality of aggregation devices,
The communication device
Aggregation device detection means for detecting a second aggregation device that is a different aggregation device from the currently connected first aggregation device and is currently connectable to the communication device;
An evaluation value indicating a degree of ease of connection with a certain aggregation device, an evaluation value calculating means for calculating an evaluation value indicating that the connection is easier as the value is smaller;
In a predetermined cycle, the evaluation value calculation unit calculates the evaluation values of the first aggregation device and the second aggregation device, and the evaluation value of the second aggregation device becomes the evaluation value of the first aggregation device. If the value is smaller than a predetermined ratio, a communication control means for connecting to the second aggregation device instead of the first aggregation device ,
The evaluation value calculation means is for calculating the evaluation value from a record of actually transmitting data to the plurality of aggregation devices,
The communication control means includes
After the elapse of a certain period until the path is stabilized after connecting with the first aggregation device, the evaluation value calculation means calculates the evaluation values of the first aggregation device and the second aggregation device, If the evaluation value of the second aggregation device is a value smaller than a predetermined ratio with respect to the evaluation value of the first aggregation device, connect to the second aggregation device instead of the first aggregation device,
If the evaluation value of the second aggregation device is smaller than the evaluation value of the first aggregation device by a certain value or more before the fixed period elapses, the second aggregation is substituted for the first aggregation device. wireless network system according to claim be tied with the device. The communication device includes a plurality of aggregation devices and a plurality of communication devices, and each of the plurality of communication devices is the communication device of the wireless network system connected to any one of the plurality of aggregation devices by multi-hop wireless communication. A wireless network control method used,
An aggregation device detection step for detecting a second aggregation device that is different from the first aggregation device that is currently connected and that is currently connectable to the communication device;
An evaluation value indicating a degree of ease of connection with a certain aggregation device, an evaluation value calculating step for calculating an evaluation value indicating that the smaller the value, the easier the connection;
At a predetermined period, the evaluation value calculation step calculates the evaluation values of the first aggregation device and the second aggregation device, and the evaluation value of the second aggregation device becomes the evaluation value of the first aggregation device. If the value is smaller than a predetermined ratio, a communication control step for connecting to the second aggregation device instead of the first aggregation device is provided .
In the evaluation value calculating step, the evaluation value is calculated from a record of actually transmitting data to the plurality of aggregation devices,
In the communication control step,
After the elapse of a certain period from when the first aggregation device is connected to when the route is stabilized, in the evaluation value calculation step, the evaluation values of the first aggregation device and the second aggregation device are calculated, If the evaluation value of the second aggregation device is a value smaller than a predetermined ratio with respect to the evaluation value of the first aggregation device, connect to the second aggregation device instead of the first aggregation device,
If the evaluation value of the second aggregation device is smaller than the evaluation value of the first aggregation device by a certain value or more before the fixed period elapses, the second aggregation is substituted for the first aggregation device. the radio network control method according to claim be tied with the device. The communication device includes a plurality of aggregation devices and a plurality of communication devices, and each of the plurality of communication devices is the communication device of the wireless network system connected to any one of the plurality of aggregation devices by multi-hop wireless communication. A wireless network control program used,
Aggregation device detection means for detecting a second aggregation device that is a different aggregation device from the currently connected first aggregation device and is currently connectable to the communication device;
An evaluation value indicating a degree of ease of connection with a certain aggregation device, an evaluation value calculating means for calculating an evaluation value indicating that the connection is easier as the value is smaller;
In a predetermined cycle, the evaluation value calculation unit calculates the evaluation values of the first aggregation device and the second aggregation device, and the evaluation value of the second aggregation device becomes the evaluation value of the first aggregation device. In contrast, if the value is smaller than a predetermined ratio, the computer functions as communication control means for connecting to the second aggregation device instead of the first aggregation device ,
The evaluation value calculation means is for calculating the evaluation value from a record of actually transmitting data to the plurality of aggregation devices,
The communication control means includes
After the elapse of a certain period until the path is stabilized after connecting with the first aggregation device, the evaluation value calculation means calculates the evaluation values of the first aggregation device and the second aggregation device, If the evaluation value of the second aggregation device is a value smaller than a predetermined ratio with respect to the evaluation value of the first aggregation device, connect to the second aggregation device instead of the first aggregation device,
If the evaluation value of the second aggregation device is smaller than the evaluation value of the first aggregation device by a certain value or more before the fixed period elapses, the second aggregation is substituted for the first aggregation device. the radio network control program characterized be tied with the device.

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