JP2011250301A - Remote meter reading system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a remote meter reading system capable of selecting and using an alternative communication channel different from that of a power-line carrier communication between a key station and a slave station so as to improve reliability of meter reading.SOLUTION: A slave station 10 acquires a used power amount of a user from an electricity meter 11. A key station 20 can communicate with the slave station 10 so as collect meter reading data acquired by the slave station 10 and notify an upper aggregation server 30 of meter reading information through a communication network 51. An inter-node communication is capable of using multi-hop communication among communication nodes such as the slave station 10 and the key station 20. When a pair of nodes between the slave station 10 and the key station 20 within a main route only including a communication channel by a power-line carrier communication cannot use the power-line carrier communication, a detour using radio communication is selected.

Description

  The present invention relates to a remote meter-reading system that enables transmission of meter-reading data using a communication path by power line carrier communication.

  In general, a supply medium such as electricity, gas, water, and heat is supplied to a customer from a supplier through a supply facility such as a transmission line, a gas conduit, a water pipe, and a heat conduit. The supply medium consumer measures the amount of supply medium used with a meter, and the supplier confirms the measurement result of the measuring instrument with a meter reader and asks the customer for the amount of supply medium used. You are charging for the price.

  The meter reading work by the meter reader requires labor costs and there are problems such as erroneous reading of the measured value. To solve this kind of problem, the measured value is managed without going through the meter reader. Various techniques have been proposed.

  For example, in an apartment house, a slave station as a communication device is connected to a meter (power meter, etc.) placed in each dwelling unit (customer), and between the master station and the slave station placed in the electrical room or manager room A technique for performing communication by power line carrier communication has been proposed (see, for example, Patent Document 1). That is, a technique has been proposed in which a distribution line laid in an apartment house is used for a communication path between a master station and a slave station, and meter reading data measured by a meter is transmitted from the slave station to the master station through the distribution line.

  In a detached house, in a customer to whom power is supplied from the secondary side of the pole transformer, a slave station is attached to the meter, and between the master station and the slave station arranged in the vicinity of the pole transformer, It has been proposed to use the distribution line on the secondary side of the pole transformer for a communication path in power line communication. A configuration has also been proposed in which a sub-master station that can communicate with the master station is provided, and meter reading data is transmitted from the slave station to the master station via the sub-master station.

  When the power line carrier communication technology is used as described above, the distribution lines for supplying power at each consumer can be used as a communication path between the master station and the slave stations, thus saving construction. However, since the communication signal used in the power line carrier communication is a small signal, it may not be able to reach directly between the master station and the slave station. In preparation for such a case, a technique for performing multi-hop communication using a slave station as a relay has been proposed.

JP 2006-180021 A

  By the way, in the above-described configuration, power line carrier communication is performed between the master station and the slave station using a distribution line as a communication path, and multihop communication is performed as necessary. Even if a long communication path exists, meter reading data can be transmitted in many cases. However, if some of the slave stations cannot be used for relaying, such as when noise is superimposed on the distribution line at the consumer, a communication path composed only of the distribution line may be used. Communication between the master station and the slave station may not be established.

  The present invention has been made in view of the above reasons, and its purpose is to make it possible to select and use a communication path different from the communication path by power line carrier communication between the master station and the slave station, To provide a remote meter-reading system that makes it possible to select a detour as a communication path, thereby improving the reliability of communication between the master station and the slave station and consequently improving the reliability of meter-reading It is in.

  In order to achieve the above object, the present invention is capable of communicating with a plurality of slave stations that acquire the usage amount of a supply medium purchased from a supplier through a supply facility in a consumer, and the slave stations can communicate with each other. Multi-hop communication in the communication between nodes with the master station that collects the acquired measurement results and notifies the upper aggregation server of meter reading information based on the measurement results through the communication network, with the master station and the slave stations as communication nodes Each node can select a first communication path by power line carrier communication using a distribution line as a communication path and a second communication path by wireless communication as communication paths with other nodes. When performing multi-hop communication between desired nodes among the nodes, when the first communication path cannot be used between any pair of nodes included in the main route including only the first communication path, This It employs a configuration for selecting the bypass path including a second communication channel between nodes.

  The detour route selected when the first communication path cannot be used between any pair of nodes included in the main route is selected by dynamically searching within the range including other nodes between the nodes. Is desirable.

  In this case, each node stores the detour route selected by dynamically searching, and when the first communication path cannot be used between the same nodes after the storage, the already stored detour route is stored. It is desirable to choose.

  Each node periodically grasps the first communication path and the second communication path between the nodes by periodically transmitting a confirmation packet for confirming the communication possibility with other nodes. One of the nodes that performs multi-hop communication sets a sub route including a detour in addition to the main route in advance, and when the first communication path cannot be used between any pair of nodes included in the main route, A sub route may be selected.

  In this case, when one of the nodes performing multi-hop communication sets the main route and the sub route, it is desirable to select a route with the best communication quality up to the other.

  Each node can select a signal strength of a radio signal from a plurality of stages, and by selecting a radio signal having a higher signal strength in order from the lowest signal strength, a node capable of communication by the selected radio communication It is desirable to form a detour between the two.

  According to the configuration of the present invention, it is possible to select and use a communication path different from the communication path by power line carrier communication between the master station and the slave station, and a detour can be selected in the communication path. Therefore, there is an advantage that the reliability of communication between the master station and the slave station is increased, and as a result, the reliability of meter reading can be increased.

It is a block diagram which shows embodiment. It is a block diagram which shows the slave station used for the same as the above. It is a block diagram which shows the master station used for the same as the above. FIG. 3 is an operation explanatory diagram of the first embodiment. FIG. 6 is an operation explanatory diagram illustrating Embodiment 2. FIG. 10 is an operation explanatory diagram illustrating the third embodiment.

  In the embodiment described below, a case where there are a plurality of consumers in one building such as a housing complex will be described. However, a case where a customer occupies one building as in a detached house. Even so, it is possible to employ a similar technique. When there are multiple customers in one building, the space where multiple customers are independent (offices, stores), such as tenant buildings used as offices and stores, as well as apartment buildings. May be occupied.

  In the embodiment, the supply company is described as an electric power company, and the supply medium is described as electricity. Therefore, each consumer measures the amount of power used by a power meter (measuring instrument). Each power meter is connected to a slave station, and the slave station acquires the amount of power used by the consumer from the power meter. Further, the slave station communicates with a master station arranged in an electrical room or a manager room in the building, and transmits a measurement result (hereinafter referred to as “meter reading data”) by the power meter to the master station. It is possible. A communication route between the slave station and the master station will be described later. In addition, when a consumer is a detached house, a master station is provided in one of the consumers connected to the secondary side of a pole transformer, or a master station is provided in a utility pole.

  In the following embodiments, the supply medium is electricity. However, meter reading data by a meter (measuring instrument) can be transmitted to the master station for a supply medium such as gas, water, and heat. A plurality of types of communication paths that constitute a communication route between the slave station and the master station are provided, and a distribution line that supplies power to each consumer is used as one of the communication paths. In order to use the distribution line for the communication path, the slave station includes a communication interface for performing power line carrier communication. In addition, a communication path using wireless communication is used as another communication path. Therefore, the slave station includes a communication interface for performing wireless communication.

(Embodiment 1)
As shown in FIG. 1, each dwelling unit provided in the apartment house 1 is a consumer, and a slave station 10 is provided in each dwelling unit. Each slave station 10 is set with a slave station ID as unique identification information to be identified during communication. Each slave station 10 is attached to a power meter 11 that individually measures the amount of power used in each dwelling unit. Therefore, the slave station ID can be used for identifying the power meter 11 for each consumer. In addition, in order to identify the power meter 11, identification information may be set in the power meter 11.

  As shown in FIG. 2, the slave station 10 includes a power line communication interface 12 for using a distribution line 50 laid in the apartment house 1 as a communication path. Furthermore, the slave station 10 includes a sub-communication interface 13 for using a communication path by wireless communication as a communication interface. The sub-communication interface 13 is normally used for communication with the maintenance terminal 40 used for maintenance of the slave station 10. The maintenance terminal 40 is used for performing inspection and setting change of the slave station 10 by performing wireless communication with the slave station 10. Therefore, the maintenance terminal 40 can be carried by a worker. Here, the master station 20 can also perform wireless communication with the maintenance terminal 40, and the master station 20 can also be maintained and inspected by the maintenance terminal 40 in the same manner as the slave station 10.

  The power line communication interface 12 is connected to the distribution line 50. The radio signal used in the sub communication interface 13 is preferably a radio wave as a transmission medium. Various standards of this type of wireless communication are known, and can be selected from various standards such as WiFi (registered trademark), ZigBee (registered trademark), and Bluetooth (registered trademark). As a transmission medium, it is also possible to use infrared rays such as IrDA instead of radio waves.

  The slave station 10 is also provided with a power meter information storage unit 14 for storing meter reading data acquired from the power meter 11. The power meter information storage unit 14 stores meter-reading data for a certain period (for example, for one day) every certain time (for example, every minute, every five minutes, every ten minutes, etc.). The slave station 10 has a slave station control unit 15 composed of a microcomputer, and the slave station control unit 15 gives various functions to the slave station 10 by executing a program. The slave station control unit 15 also has a function of determining a communication route to be described later. The function of the slave station 10 will be described later.

  The slave station 10 can communicate with the master station 20 through the distribution line 50 connected to the power line communication interface 12. The master station 20 is disposed in an electrical room or a manager room (not shown) in the apartment house 1. As shown in FIG. 3, the master station 20 includes a host system communication interface 21 for connecting to a communication network 51 (see FIG. 1) such as the Internet or a dedicated line for remote meter reading. The host communication interface 21 can perform high-speed and large-capacity communication by using, for example, an optical line as the communication network 51. The master station 20 uses a power line communication interface 22 for communicating with the slave station 10 using the distribution line 50 as a communication path, and a sub-communication interface 23 for using a communication path by wireless communication. Provide as an interface.

  The master station 20 can communicate with a plurality of slave stations 10, and includes a management information storage unit 24 that stores meter reading data acquired from the slave station 10 together with a slave station ID, and a master station control unit 25 that includes a microcomputer. Prepare. The master station control unit 25 gives various functions to the master station 20 by executing a program. The master station control unit 25 also has a function of determining a communication route to be described later. The function of the master station 20 will be described later.

  The master station 20 communicates with an upper aggregation server 30 (see FIG. 1) operated by a power company or a service provider that provides a total amount of power through the communication network 51. Thereby, the master station 20 transmits meter reading information based on the meter reading data (measurement result) for each power meter 11 acquired from the slave station 10 to the upper aggregation server 30. That is, the master station 20 processes the meter reading data acquired from the slave station 10 if necessary, and transmits the processed data to the upper aggregation server 30.

  The master station 20 collects and collects meter reading data from the slave station 10 to generate meter reading information, and transmits the generated meter reading information to the upper summarizing server 30. Further, the upper aggregation server 30 has a function of acquiring meter reading data from the slave station 10 via the master station 20 as necessary. The slave station 10 is provided with a switch (not shown) that can supply and shut off power to the consumer. The upper aggregation server 30 opens and closes the switch via the master station 20. It is also possible to instruct.

  Meter reading data collected by the slave station 10 and stored in the power meter information storage unit 14 is periodically collected by the master station 20. For example, the master station 20 requests the slave station 10 to transmit meter reading data by communication at a specified time (for example, 0:00) once a day, and transfers the meter reading data from the slave station 10. . At this time, the meter reading data stored in the power meter information storage unit 14 after the previous request is transferred to the master station 20. Such meter reading performed periodically is hereinafter referred to as “periodic meter reading”.

  By the way, when the master station 20 transmits the meter reading data acquired from the slave station 10 to the upper aggregation server 30 by the periodic meter reading, the meter reading data acquired by the upper aggregation server 30 may be leaked depending on the communication state or the like. . In preparation for such a case, the upper aggregation server 30 also has a function of designating the slave station 10 and acquiring meter reading data from the specific slave station 10 via the master station 20. By using this function, it is possible to complement the leaked meter reading data.

  In the above-described operation, the master station 20 performs communication using the power line carrier communication technique using the distribution line 50 as a communication path in order to receive meter reading data from the slave station 10. However, the communication signal used for the power line carrier communication does not affect the quality of the power supplied to the customer through the distribution line 50 or affect the electric equipment as radiation noise. A small electric power is used. Therefore, when the distance between the slave station 10 and the master station 20 increases, there may occur a problem that a communication signal with sufficient power cannot be transmitted from the slave station 10 to the master station 20.

  In order to avoid such a problem, the slave station 10 enables multi-hop communication. That is, the slave station 10 has a function of transferring the communication signal of the other slave station 10 to the other slave station 10 or the master station 20. Therefore, even when communication cannot be directly performed between the master station 20 and the slave station 10, it is possible to establish communication between the master station 20 and the slave station 10 via another slave station 10. It has become. By enabling multi-hop communication in this way, the communication success rate between the master station 20 and the slave station 10 is high.

  In determining a communication route using multi-hop communication, various proposed techniques may be used. For example, it is possible to use a technique in which each node (slave station 10 and master station 20) in communication periodically transmits a confirmation packet (a so-called Hall packet) to confirm the communication possibility between the nodes. In this case, the communication possibility information acquired by the response to the confirmation packet is notified to other nodes, and the communication route to the target node is searched. As this type of technology, there is known OLSR (Optimized Link State Routing Protocol) defined in RFC3626 issued by IEFT (Internet Engineering Task Force).

  In short, it is possible to apply a route search algorithm such as the Dijkstra algorithm by acquiring information on the possibility of communication with adjacent nodes. As a result, it becomes possible to search for an available communication route among a plurality of communication routes existing between the slave station 10 and the master station 20. Such communication route search is performed by the slave station control unit 15 in the slave station 10 and the master station control unit 25 in the master station 20.

  Hereinafter, an operation example will be described. Assume that the master station 20 is the node 0 and the meter reading data is acquired from the slave station 10 that is the node n. Here, the master station 20 that is the node 0 communicates with the slave station 10 that is the node n via the slave station 10 that is the node 1 and the slave station 10 that is the node 2 by the route selection technique as described above. A case where a communication route is selected will be described as an example. That is, as shown in the upper part of FIG. 4, communication by power line carrier communication is described in the communication route of node 0 → node 1 → node 2 → node n (in FIG. 4, “PLC data communication” is described later. The same applies to FIGS. 5 and 6.

  As described above, between the slave station 10 and the master station 20, each slave station 10 in the apartment house 1 is connected to the master station 20 by performing communication using the power line carrier communication technology and the multi-hop communication technology. Can communicate with each other through the distribution line 50. However, since the distribution line 50 is used for the communication path, the communication situation deteriorates due to a temporary increase in noise, and some of the slave stations 10 communicate with the master station 20 as shown in the lower part of FIG. There is a possibility that it becomes impossible (a cross indicates a communication failure).

  In preparation for such a case, in the present embodiment, sub-communication interfaces 13 and 23 are provided in the slave station 10 and the master station 20, and communication including a communication path by wireless communication between the slave station 10 and the master station 20 is provided. It is possible to form a route. When communication using the distribution line 50 fails as a communication path by wireless communication, or when communication using the distribution line 50 as a communication path cannot be used, each node (slave station 10 or master station 20). The control units 15 and 25 select. That is, when power line carrier communication using the distribution line 50 as a communication path cannot be used, the communication path by wireless communication can be used as a detour and the communication success rate is increased (communication path by wireless communication). 4 is described as “wireless communication data communication” in FIG. 4. Note that the same applies to FIGS.

  When nodes are arranged close to each other, it is possible to communicate with each other using a communication path by wireless communication. However, when nodes are not arranged adjacent to each other, wireless communication is relayed. Communication between nodes may be established via another device. In some cases, the maintenance terminal 40 used for maintenance inspection can be used for relaying.

  If there is a slave station 10 that has failed to acquire meter-reading data, the maintenance terminal 40 is used as a relay device in the vicinity of the slave station 10, so that the slave station 10 and another slave station 10 or the master station 20 are used. Communication is possible. For example, when a communication path using the distribution line 50 is temporarily unable to communicate and the maintenance terminal 40 inspects the slave station 10, the maintenance terminal 40 relays if the slave station 10 is not faulty. As a device, a communication path between the slave station 10 and the master station 20 is secured.

  In the example shown in FIG. 4, a case is shown in which a communication route using a communication path by wireless communication is predetermined between the node 1 and the node 2. This communication route is set as a communication route for performing direct communication between the node 1 and the node 2 without going through the maintenance terminal 40. In FIG. 4, among the arrows indicating communication, a solid line represents communication by power line carrier communication using the distribution line 50 as a communication path, and a broken line represents communication using a wireless communication path.

  Here, as shown in the lower part of FIG. 4, communication from node 0 (master station 20) to node n (slave station 10) via node 1 (slave station 10) and node 2 (slave station 10) is performed. Consider a case where communication between the node 1 and the node 2 fails when performing. In this case, since the slave station 10 serving as the node 1 detects a communication failure with the slave station 10 serving as the node 2, the control unit 15 of the node 1 selects a communication path by wireless communication as a communication route with the node 2. To do. Here, before performing communication between the node 1 and the node 2, it may be detected in advance whether or not the communication path between the node 1 and the node 2 can be used by using a confirmation packet. . After the node 1 succeeds in communication with the node 2 by wireless communication, the node 1 returns to the state where the distribution line 50 is used for the communication path. That is, after transmitting the prescribed number of packets to the node 2 using the communication path by wireless communication, the distribution line 50 is returned to the state used for the communication path.

  In the above-described operation, since the communication path by wireless communication is adopted only between the node 1 and the node 2, the distribution line 50 is used for the communication path between the node 2 and the node n. As described above, when the communication route between the slave station 10 and the master station 20 includes a communication path by power line carrier communication and a communication path by wireless communication, information used in the power line carrier communication in a packet used for wireless communication. It is desirable to encapsulate. In this case, since the message included in the wireless communication packet can be used as it is as a communication signal in the power line carrier communication at the node that has received the packet by wireless communication, the processing load on the receiving side is reduced.

  In addition, although the communication path which directly performs wireless communication and the communication path which performs wireless communication via the maintenance terminal 40 are illustrated as the communication path that bypasses the communication path by the power line carrier communication, the slave station 10 is a customer's wireless It is also possible to adopt a configuration in which communication is performed using a LAN as part of a communication path. As described above, when communication by power line carrier communication using the distribution line 50 as a communication path is temporarily disabled, communication can be performed through the detour, so that the success rate of communication can be increased.

(Embodiment 2)
In the first embodiment, the case where the communication path by wireless communication is predetermined between the nodes has been described. On the other hand, in the present embodiment, a case will be described in which it is determined whether or not a communication path by wireless communication is usable between each pair of nodes, and an available communication path is dynamically selected. That is, if there is a node that has failed to communicate with the next node in the communication path between the slave station 10 and the master station 20 from which the meter reading data is to be acquired, wireless communication including the other nodes is performed at the node. Search for possible nodes.

  When a node that can be used for wireless communication is detected in a communication path with the slave station 10 that is to acquire meter-reading data, wireless communication is performed with the node, and a target child is obtained. Communication with the station 10 is performed. Here, when searching for a node capable of wireless communication, a case where the searched node further performs wireless communication with another node is included. In other words, multi-hop communication by wireless communication between nodes is allowed. In the present embodiment, a wired communication path and a wireless communication path are provided between the nodes, and if the wired communication path cannot be used between the nodes, the communication path is duplexed so that the wireless communication path is used. In the above, multi-hop communication is enabled.

  As shown in FIG. 5, a specific example is shown in which the master station 20 (node 0) acquires meter reading data from the slave station 10 (node n) through the communication route of node 0 → node 1 → node 2 → node n. explain. Here, as in the first embodiment, if communication from the node 1 to the node 2 fails, the node 1 searches for a communication path to the node 2 from the communication paths by wireless communication. In the illustrated example, the search of the communication path results in that communication between the node 1 and the node 2 is possible if the communication route is the node 1 → the node 4 → the node 2 when passing through the node 4. Shows the case. Therefore, communication from the node 1 to the node 2 is performed using the extracted communication path by wireless communication. In the illustrated example, communication between the node 2 and the node n is performed by power line carrier communication.

  In searching for a communication path by wireless communication, for example, a technique such as DSR (Dynamic Source Routing) proposed by IEFT MANET (Mobile Ad-hoc Networks) WG is used.

  In the illustrated example, when communication with the node 2 in the node 1 fails, the communication route to the node 2 that is the communication partner of the node 1 in the power line carrier communication is searched. And the node n need only be able to communicate with each other. Therefore, when a communication failure is detected in node 1, a communication path that is not a communication route to node 2 but a communication route to node n may be searched.

  As described above, wired communication by power line carrier communication is always performed, and the communication path by wireless communication is used as a detour, so the power supplied to the sub communication interfaces 13 and 23 used for wireless communication is always reduced. It is desirable to make it. Therefore, it is desirable that the output is stopped or reduced in the sub-communication interfaces 13 and 23 on the transmission side, and the reception is intermittently performed in the sub-communication interfaces 13 and 23 on the reception side. . Alternatively, on the receiving side, it is possible to provide an activation circuit that is activated by reception of a radio signal and to supply power to the reception circuit by activation of the activation circuit. By using this type of circuit, a so-called sleep state is entered during standby, and power consumption is suppressed.

  As described above, when a wired communication path by power line carrier communication cannot be used, when a communication path by a wireless signal is searched and a communication path is dynamically determined, a wireless communication path once successful in communication is If it is stored in the station control unit 15 or the master station control unit 24, it can be used for the next time. In other words, since a node that has failed in communication may fail in the future, if communication with that node has failed, if a communication path of wireless communication that has already been used is preferentially used. The possibility of successful communication without searching for a communication path increases. As described above, if the search is not performed, the communication path is determined quickly, and it becomes possible to prevent the communication response speed from being lowered. In addition, the amount of wireless communication for searching for a detour is reduced, leading to suppression of power consumption.

  Furthermore, since the technology of multi-hop communication is used not only for the selection of the communication path by power line carrier communication but also for the determination of the communication path by wireless communication, a confirmation packet by wireless communication is sent from each node at predetermined intervals in advance. It is also possible to search and store communication paths (detours) that can be used between the nodes in advance. By searching for a detour in advance in this way, it is not necessary to search for a detour after communication by power line carrier communication has failed, and a decrease in communication response speed can be prevented. In addition, it is possible to cope with a case where the communication path by wireless communication changes dynamically.

  In the above-described operation, the strength of the wireless signal used for wireless communication is not mentioned, but the strength of the wireless signal can be selected from a plurality of stages, and a communication path capable of communicating with a wireless signal having the smallest possible strength is given priority. You may make it select. For example, the wireless signal strength can be selected from three levels, strong, medium and weak, and a communication path is searched using the wireless signal with the minimum strength. If no communication path is found, the wireless signal strength is set in order. It is possible to employ a configuration for performing a search for a communication channel by increasing it. With this configuration, it is possible to search for a communication path that requires less power for wireless communication. Further, since the strength of the radio signal is made as small as possible, interference of the radio signal can be prevented.

  If the technique of this embodiment is adopted, it is not necessary to set a fixed communication path by wireless communication as in the first embodiment, and an appropriate communication path is automatically searched. In addition, even if the wireless communication environment changes, the communication path is dynamically set, so that the communication success rate increases. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 3)
In the second embodiment, when communication by power line carrier communication between the parent electrode 20 and the slave station 10 fails, a wireless communication path is dynamically selected. On the other hand, in this embodiment, before starting communication between the master station 20 and the slave station 10, a search is made in advance for a communication route that can be used between the master station 20 and the slave station 10. A technology that uses a communication route including a communication path by wireless communication that is obtained in advance when communication by carrier communication fails is adopted.

  In this embodiment, in order to search for a communication route including a communication path by wireless communication in advance, information on communication possibility when wireless communication is performed between the slave stations 10 is acquired, and the acquired information is The data is transferred between the slave stations 10 by power line carrier communication. The communication possibility information in the power line carrier communication is acquired by using the confirmation packet in the same manner as the search for the communication path in the multi-hop communication of the slave station 10 in the power line carrier communication described in the first embodiment. That is, each node (slave station 10 and master station 20) periodically transmits a confirmation packet in power line carrier communication to acquire information on communication possibility between the nodes. On the other hand, the communication possibility of wireless communication is determined not using the confirmation packet but using the communication status acquired at the time of wireless communication transmission between nodes. The result is notified to each node as link information between nodes (communication node information and communication quality) included in a confirmation packet in power line carrier communication.

  In this way, since not only the communication path for power line carrier communication but also the communication path for wireless communication is searched, it is possible to dynamically select a detour that is a communication path for wireless communication. As described in the first embodiment, a technique similar to the selection of a communication path in multi-hop communication by power line carrier communication may be used for selecting a detour.

  Through the above-described operation, each node holds the link information of the communication path of the wireless communication along with the link information of the communication path of the power line carrier communication, so that the communication path by wireless communication from each node can be obtained. When obtaining a communication path between nodes, a communication route using only power line carrier communication is obtained as a main route, and a communication route including a communication route by wireless communication is also obtained as a sub route.

  For example, when performing communication from node 0 to node n, as shown in FIG. 6, “node 0 → node 1 → node 2 → node n” is obtained as a main route using only power line carrier communication, and wireless communication is performed. As a sub route including “node 0 → node 1 → node 4 → node 2 → node n”, it can be obtained. Thus, by obtaining the main route and the sub route in advance, when communicating from the node 0 to the node n, the communication using the main route is attempted first, and when the communication using the main route fails, A sub route can be selected and communicated.

  With the above-described operation, even when communication fails only with power line carrier communication, the communication success rate can be improved by performing communication using a communication route (sub route) including a bypass route by wireless communication. Moreover, since a bypass route by wireless communication is dynamically searched, there is no need to set a sub route. Furthermore, since the sub route including the detour route is searched in advance before the communication failure is detected, the communication responsiveness is improved as compared with the case where the detour is searched after the communication failure. . In addition, since the confirmation packet is transmitted by using only the power line carrier communication without transmitting the confirmation packet by wireless communication, the use frequency of the wireless communication can be reduced. It leads to reduction of power consumption.

  In addition, link information by wireless communication between nodes included in a confirmation packet in power line carrier communication may include not only link information on one type of signal strength but also link information when the signal strength is changed. . For example, link information between nodes may be obtained using strong, medium, and weak three-level signal strength, and a sub route may be obtained using link information corresponding to the signal strength. In this case, an increase in power consumption can be suppressed by selecting a sub route that minimizes the total strength of the radio signals.

  By the way, as described above, since the confirmation packet used in the power line carrier communication includes not only the link information of the power line carrier communication but also the link information of the wireless communication, the communication route in which the power line carrier communication and the wireless communication are mixed is used. It is possible to select. In this case, it is desirable to select the communication route by giving priority to the communication quality in consideration of the communication quality. When the communication route selected in this way is used as the main route, it is possible to select a communication route with a high communication success rate.

  However, since wireless communication is affected by the surrounding radio wave environment, the communication quality between nodes is likely to change compared to power line carrier communication, and the communication route is likely to change with time. In consideration of this point, when selecting the sub route, the communication quality between nodes should be weighted so that the communication path by power line carrier communication is preferentially adopted over the communication path by wireless communication. Is desirable.

  When weighting as described above is performed, when a sub route is selected, a communication path by power line carrier communication is preferentially selected while allowing a mixture of a communication path by power line carrier communication and a communication path by wireless communication to be allowed. Therefore, the stability of communication becomes high. Moreover, since the use of a communication path by wireless communication can be suppressed, an increase in power consumption can be suppressed.

  Other configurations and operations are the same as those in the first and second embodiments. In addition, in this embodiment, the same techniques as those in the first and second embodiments are adopted for techniques such as packet encapsulation, suppression of power consumption during standby of wireless communication, and selection of wireless signal strength. Can do.

10 Slave station 20 Master station 30 Host aggregation server 40 Maintenance terminal 50 Distribution line

Claims (6)

  A plurality of slave stations that acquire the usage amount of the supply medium purchased from the supplier through the supply equipment in the consumer, and the measurement results obtained by the slave stations that are communicable with the slave stations are collected through the communication network A master station for notifying the upper aggregation server of meter reading information based on the measurement result, and using the master station and the slave station as communication nodes, enabling multi-hop communication in communication between the nodes, Can select a first communication path by power line carrier communication using a distribution line as a communication path and a second communication path by wireless communication as communication paths with other nodes, respectively, When the first communication path cannot be used between any pair of the nodes included in the main route including only the first communication path when performing multi-hop communication between the desired nodes, the node Remote meter reading system and selects a detour path that includes a second communication path between the de.   The detour route selected when the first communication path cannot be used between any pair of nodes included in the main route is dynamically searched in a range including other nodes between the nodes. The remote meter reading system according to claim 1, which is selected by the following.   Each of the nodes stores the detour route selected by dynamically searching, and when the first communication path cannot be used between the same nodes after storage, the detour route already stored is stored The remote meter reading system according to claim 2, wherein:   Each of the nodes dynamically transmits a confirmation packet for confirming the possibility of communication with other nodes, thereby dynamically setting the first communication path and the second communication path between the nodes. And one of the nodes performing multi-hop communication sets in advance a sub route including the detour in addition to the main route, and between the pair of nodes included in the main route, The remote meter reading system according to claim 1, wherein the sub route is selected when one communication path cannot be used.   5. The remote meter reading system according to claim 4, wherein when one of the nodes performing multi-hop communication sets the main route and the sub route, the route having the best communication quality up to the other is selected. .   Each of the nodes is capable of selecting the signal strength of a radio signal from a plurality of stages, and by selecting a radio signal having a higher signal strength in order from the lowest signal strength, a node capable of communication by the selected radio communication The remote meter reading system according to any one of claims 2 to 5, wherein the detour is formed between the remote meter and the remote meter.

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