JP7755455B2 - Communication base station - Google Patents

Description

The present invention relates to a communication base station.

Patent Document 1 discloses a communication system comprising multiple communication terminal devices, a data accumulation server, and a network. The communication system of Patent Document 1 distributes the data transmission times of each communication terminal device to avoid congestion. Specifically, in the communication system of Patent Document 1, each communication terminal device calculates its own delay time relative to a set time common to all communication terminal devices so that the data transmission times of each communication terminal device are distributed, and determines the data transmission time by adding its own delay time to the set time.

JP 2017-175481 A

However, with the technology disclosed in Patent Document 1, the time interval between data transmission times for each communication terminal device is uniformly set to the same time interval. Therefore, as the number of communication terminal devices increases, the time required for all communication terminal devices to complete communication increases in proportion to the number of communication terminal devices.

The present invention was made in consideration of the above-mentioned problems, and its purpose is to provide a communication base station that can shorten the time required for communication to be completed by all communication slave stations, compared to a configuration in which the same time interval is uniformly set for the communication start times of each communication slave station.

According to one aspect of the present invention, a communication base station communicates with a plurality of communication slaves. The plurality of communication slaves includes a first communication slave and a second communication slave. The first communication slave communicates directly with the communication base station. The second communication slave communicates with the communication base station via at least one other communication slave among the plurality of communication slaves. Each of the plurality of communication slaves communicates with the communication base station via at least one link established between the communication base station and the communication base station. The hop count indicating the number of links of the first communication slave indicates 1. The hop count of the second communication slave increases in accordance with the number of other communication slaves between the communication base station and the communication base station. The communication base station includes a setting unit. The setting unit sets the communication start time of each of the plurality of communication slaves based on the hop count of each of the plurality of communication slaves.

The communication base unit according to the present invention can shorten the time required for all communication devices to complete communication, compared to a configuration in which the same time interval is uniformly set for the communication start times of each communication device.

1 is a diagram illustrating a communication system including a communication master unit according to an embodiment of the present invention. FIG. 2 is a block diagram showing a configuration of a communication master device according to the embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of a communication slave unit. 5 is a flowchart illustrating a process executed by a control unit of the communication master device according to the embodiment of the present invention. 5 is a flowchart illustrating a process executed by a control unit of the communication master device according to the embodiment of the present invention. FIG. 10 is a diagram illustrating an example of a time interval. FIG. 10 is a diagram illustrating an example of a communication start time. FIG. 4 is a sequence diagram illustrating an example of an operation of the communication master device according to the embodiment of the present invention. FIG. 4 is a sequence diagram illustrating an example of an operation of the communication master device according to the embodiment of the present invention. FIG. 10 is a sequence diagram illustrating an example of an operation of a communication slave device. FIG. 10 is a sequence diagram illustrating an example of an operation of a communication slave device. 5 is a flowchart illustrating a process executed by a control unit of the communication master device according to the embodiment of the present invention. FIG. 10 is a diagram illustrating an example of communication time. FIG. 10 is a diagram illustrating an example of an updated communication start time. FIG. 10 is a sequence diagram illustrating an example of an operation of a communication slave device.

The following describes an embodiment of the communication base unit of the present invention with reference to the drawings (Figs. 1 to 15). However, the present invention is not limited to the following embodiment, and can be implemented in various forms without departing from the spirit of the invention. Note that where explanations overlap, they may be omitted as appropriate. Furthermore, the same or equivalent parts in the drawings will be designated by the same reference numerals, and explanations will not be repeated.

Figure 1 shows a communication system 100 including a communication base unit 1 according to this embodiment. In this embodiment, the communication system 100 is a telemetry system in which measurement values from multiple meters 3 are collected by a central device 4.

As shown in FIG. 1, in this embodiment, the communication system 100 includes a communication base unit 1, multiple communication slave units 2, multiple meters 3, a center device 4, and a center-side network control device 5. Hereinafter, the communication base unit 1 may be referred to as the "base unit 1." Furthermore, the communication slave unit 2 may be referred to as the "slave unit 2."

Meter 3 is a measuring device related to resources or energy. Meter 3 measures, for example, gas, water, or electricity. Meter 3 is installed at each consumer, such as a private home, a company, or various facilities. Meter 3 measures, for example, the amount of gas, water, or electricity used, and outputs the measurement value as the measurement result.

The base unit 1 communicates with multiple slave units 2. A slave unit 2 is installed for each meter 3. Each slave unit 2 transmits to the base unit 1 a message indicating the measurement value output from the corresponding meter 3. Specifically, each slave unit 2 performs scheduled meter reading and transmits a message indicating the measurement value to the base unit 1 at a predetermined time. Scheduled meter reading refers to the process of obtaining a measurement value from a meter 3 at a predetermined date and time. For example, each slave unit 2 obtains a measurement value from its corresponding meter 3 at Y hour, Y minute, Y second on Y day of every month. Hereinafter, a message indicating a measurement value may be referred to as a "measurement value message."

The multiple handset units 2 include handset units 2 that communicate directly with the base unit 1 and handset units 2 that communicate with the base unit 1 via at least one other handset unit 2 among the multiple handset units 2. Hereinafter, a handset unit 2 that communicates directly with the base unit 1 may be referred to as a "first handset unit 2A." A handset unit 2 that communicates with the base unit 1 via at least one other handset unit 2 among the multiple handset units 2 may be referred to as a "second handset unit 2B." Communication between the base unit 1 and the first handset unit 2A, and communication between handset units 2, may use, for example, specified low-power radio communication. The frequency band for specified low-power radio communication is, for example, the 920 MHz band.

Each of the multiple slave devices 2 communicates with the base device 1 via at least one link L established between the base device 1 and the slave device 2 with which it communicates. Hereinafter, the number of links L established between the base device 1 and the slave device 2 with which it communicates may be referred to as the "hop count HP." The hop count HP of the first slave device 2A is "1." The hop count HP of the second slave device 2B increases in accordance with the number of other slave devices 2 between it and the base device 1.

In this embodiment, the multiple slave units 2 include five slave units 2a to 2e, and the multiple meters 3 include five meters 3a to 3e. After slave unit 2a acquires the measurement value of meter 3a, it creates and transmits to master unit 1 telegram D31 (measurement value telegram D31) indicating the measurement value of meter 3a. Similarly, slave units 2b to 2e transmit to master unit 1 telegrams D32 to D35 (measurement value telegram D32 to measurement value telegram D35) indicating the measurement values of meters 3b to 3e, respectively.

Of the five slave devices 2a to 2e, slave device 2a and slave device 2d are the first slave devices 2A, and slave devices 2b, 2c, and 2e are the second slave devices 2B. Therefore, the hop count HP for slave devices 2a and 2d is "1." The hop count HP for slave devices 2b, 2c, and 2e increases in accordance with the number of other slave devices 2 between them and the master device 1.

Specifically, of the five slave devices 2a-2e, three slave devices 2a-2c form the first communication route Rt1. Of the five slave devices 2a-2e, two slave devices 2d and 2e form the second communication route Rt2. Device 2b, which is included in the first communication route Rt1, communicates with the master device 1 via slave device 2a. Device 2c, which is included in the first communication route Rt1, communicates with the master device 1 via slave devices 2a and 2b. Device 2e, which is included in the second communication route Rt2, communicates with the master device 1 via slave device 2d. Therefore, the hop count HP of slave devices 2b and 2e is "2," and the hop count HP of slave device 2c is "3."

When handset 2a communicates with base unit 1, a first link L1 is formed between handset 2a and base unit 1. When handset 2b communicates with base unit 1, a first link L1 and a second link L2 are formed between handset 2b and base unit 1. The second link L2 is formed between handset 2b and base unit 2a. When handset 2c communicates with base unit 1, the first link L1 to the third link L3 are formed between handset 2c and base unit 1. The third link L3 is formed between handset 2c and base unit 2b. When handset 2d communicates with base unit 1, a fourth link L4 is formed between handset 2d and base unit 1. When handset 2e communicates with base unit 1, a fourth link L4 and a fifth link L5 are formed between handset 2e and base unit 1. The fifth link L5 is formed between handset 2e and base unit 2d.

Each of the multiple sub-units 2 is assigned an identification code ID. The identification code ID is, for example, a number. In this embodiment, sub-unit 2a is assigned the identification code ID "N1." Similarly, sub-units 2b to 2e are assigned the identification code IDs "N2" to "N5," respectively.

The parent unit 1 sets the communication start time T after the scheduled meter reading for each child unit 2. For example, the parent unit 1 sets the communication start time T after the scheduled meter reading for each child unit 2 when installing the parent unit 1 and five child units 2a to 2e. Alternatively, the parent unit 1 sets the communication start time T after the scheduled meter reading for each child unit 2 when installing additional child units 2. Hereinafter, the communication start time T after the scheduled meter reading may be referred to as the "communication start time T."

The communication start time T indicates the time at which the slave unit 2 starts communication to transmit the meter 3 measurement value to the master unit 1. The master unit 1 sets a different communication start time T for each slave unit 2. As a result, congestion can be avoided.

When the current time reaches communication start time T, each slave unit 2 starts communication and sends a measurement value message to the master unit 1. After master unit 1 receives measurement value messages D31 to D35 from slave units 2a to 2e, it sends message D3 indicating the measurement values of meters 3a to 3e to the center device 4. Note that master unit 1 may also send a message indicating the measurement value to the center device 4 each time it receives a measurement value message from a slave unit 2.

Specifically, the base unit 1 is connected to a wide-area wireless network Ne via wireless communication and is communicatively connected to a center-side network control device 5 via the wide-area wireless network Ne. The center device 4 is communicatively connected to the center-side network control device 5. The wide-area wireless network Ne is, for example, a PHS (Personal Handy-phone System) network, a FOMA (Freedom Of Mobile Multimedia Access) network, an LTE (Long Term Evolution) network, a 4G (Fourth Generation Mobile Communication System) network, or a 5G (Fifth Generation Mobile Communication System) network.

The center-side network control device 5 is installed, for example, in a telecommunications carrier's public network. The center-side network control device 5 controls communication between the base unit 1 and the center device 4 via the wide-area wireless network Ne.

For example, if the meter 3 is a gas meter, the center device 4 is managed by the gas supplier. The center device 4 acquires the meter 3 measurement values from messages received from the base unit 1 via the wide area wireless network Ne and the center-side network control device 5, and stores the measurement values for each meter 3. In other words, the center device 4 stores the meter 3 measurement values for each consumer. The center device 4 includes, for example, a server.

In this embodiment, the meter 3 is not connected to the parent unit 1, but the meter 3 may be connected to the parent unit 1.

Next, the base unit 1 will be described with reference to Figures 1 and 2. Figure 2 is a block diagram showing the configuration of the communication base unit 1 of this embodiment. As shown in Figure 2, the base unit 1 includes a first communication unit 11, a second communication unit 12, a memory unit 13, a clock circuit 14, and a control unit 15.

The first communication unit 11 is communicatively connected to the center device 4. Specifically, the first communication unit 11 is communicatively connected to the center device 4 via the wide area wireless network Ne and the center-side network control device 5. More specifically, the first communication unit 11 is communicatively connected to the wide area wireless network Ne via wireless communication. Then, it transmits and receives messages to and from the center-side network control device 5 via the wide area wireless network Ne. As a result, messages are transmitted and received between the first communication unit 11 and the center device 4. The first communication unit 11 is a communication module capable of wide area communication such as with a PHS network, a FOMA network, an LTE network, a 4G network, and a 5G network.

The second communication unit 12 performs wireless communication with the handset 2. Specifically, the second communication unit 12 forms a link L with the first handset 2A and transmits and receives messages to and from the first handset 2A. In this embodiment, the second communication unit 12 performs wireless communication with the handset 2a and handset 2d. The second communication unit 12 includes, for example, a communication module having an RF-LSI for 920 MHz band communication.

The memory unit 13 stores various computer programs and various data. The various computer programs include, for example, a computer program for setting the communication start time T for each handset 2. The various data include, for example, the identification code ID of the device itself (parent device 1) and each handset 2, destination information for the device itself (parent device 1) and each handset 2, the communication route Rt for each handset 2, and data indicating the number of hops HP for each handset 2. The memory unit 13 includes, for example, semiconductor memory such as ROM (Read Only Memory), RAM (Random Access Memory), and flash memory.

The clock circuit 14 keeps track of the time. The control unit 15 obtains the current time based on the time kept by the clock circuit 14.

The control unit 15 controls each element of the device. For example, the control unit 15 controls the first communication unit 11, the second communication unit 12, the memory unit 13, and the clock circuit 14. Specifically, the control unit 15 has a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The processor controls each element of the device by executing a computer program stored in the memory unit 13. The control unit 15 and the memory unit 13 may form a microcomputer.

The control unit 15 executes various processes. Specifically, the processor executes computer programs stored in the storage unit 13 to execute various processes. For example, the control unit 15 executes a process to set the communication start time T for each handset 2. Specifically, the control unit 15 sets the communication start time T for each of the multiple handset 2 based on the number of hops HP for each of the multiple handset 2. The control unit 15 is an example of a "setting unit."

According to this embodiment, the communication start time T for each handset 2 is set based on the hop count HP of each handset 2, which makes it possible to shorten the time required for all handset 2 to complete communication compared to a configuration in which the same time interval is set for all handset 2 communication start times T. Specifically, by making the time interval X between the communication start time T of a handset 2 with a low hop count HP and the communication start time T of the next handset 2 to start communication shorter than the time interval X between the communication start time T of a handset 2 with a high hop count HP and the communication start time T of the next handset 2 to start communication, it is possible to shorten the time required for all handset 2 to complete communication.

In this embodiment, the control unit 15 determines, for each of the multiple slave devices 2, a time interval X for starting communication with the base device 1 based on the hop count HP of each of the multiple slave devices 2. Then, based on each time interval X, a communication start time T is set for each of the multiple slave devices 2. Specifically, the time interval X includes a first time interval X1 and a second time interval X2. The first time interval X1 indicates the time interval X set after communication starts for a slave device 2 whose hop count HP is the first hop count. The second time interval X2 indicates the time interval X set after communication starts for a slave device 2 whose hop count HP is the second hop count, which is greater than the first hop count. The control unit 15 determines each time interval X so that the second time interval X2 is greater than the first time interval X1.

For example, the first hop count is "1," and the slave devices 2 with the hop count HP of the first hop count are slave devices 2a and 2d. Furthermore, the second hop count is "2," and the slave devices 2 with the hop count HP of the second hop count are slave devices 2b and 2e. The control unit 15 determines each time interval X so that the time interval X (second time interval X2) set after slave devices 2b and 2e start communication is longer than the time interval X (first time interval X1) set after slave devices 2a and 2d start communication.

More specifically, the parent unit 1 (first communication unit 11) receives a message D1 indicating the date and time of the scheduled meter reading from the center device 4. The control unit 15 extracts the meter reading time t1 from the date and time of the scheduled meter reading. Then, based on the meter reading time t1 and each time interval X, it sets the communication start time T for each of the multiple child units 2. The meter reading time t1 is an example of a "set time." Hereinafter, the message D1 indicating the date and time of the scheduled meter reading may be referred to as the "regular meter reading setting message D1." Furthermore, the date and time of the scheduled meter reading may be referred to as the "regular meter reading date and time."

Furthermore, when the second communication unit 12 receives a measurement value telegram, the control unit 15 acquires the reception time, which is the time when the measurement value telegram was received, and stores this in the memory unit 13. More specifically, when the second communication unit 12 receives a measurement value telegram, the control unit 15 acquires the current time from the clock circuit 14 and stores the time acquired from the clock circuit 14 in the memory unit 13 as the reception time. The control unit 15 is an example of an "acquisition unit." The control unit 15 receives measurement value telegrams D31 to D35 from all slave units 2a to 2e, stores the reception times of all measurement value telegrams D31 to D35 in the memory unit 13, and then updates the communication start time T of each slave unit 2 based on the reception times stored in the memory unit 13.

According to this embodiment, the communication start time T for each slave device 2 can be updated based on the actual time at which the measurement value was received from each slave device 2, thereby further shortening the time required for communication between all slave devices 2 to be completed.

Specifically, the control unit 15 updates the communication start time T of each handset 2 so that the handset 2 with the largest difference between its communication start time T and its reception time will be the last to start communicating with the base unit 1. More specifically, the time interval X set for the handset 2 with the largest difference between its communication start time T and its reception time is the longest among the time intervals X set for each handset 2. Therefore, by having the handset 2 with the largest difference between its communication start time T and its reception time communicate with the base unit 1 last, the waiting time due to the longest time interval X can be eliminated. As a result, the time required for all handset 2 to complete communication can be further shortened. In this embodiment, the control unit 15 updates the communication start time T of each handset 2 so that communication with the base unit 1 is performed in ascending order of the difference between the communication start time T and its reception time.

Next, the handset 2 will be described with reference to Figures 1 to 3. Figure 3 is a block diagram showing the configuration of the communication handset 2. As shown in Figure 3, the handset 2 includes a connection unit 21, a communication unit 22, a memory unit 23, a clock circuit 24, and a control unit 25.

The connection unit 21 connects to the meter 3. Specifically, the connection unit 21 has at least one port. One end of the electric wire PL is connected to the port of the connection unit 21. The electric wire PL includes a signal line and a ground line. The connection unit 21 is wired to the meter 3 via the electric wire PL. The control unit 25 acquires measurement values from the meter 3 via the connection unit 21.

The communication unit 22 performs wireless communication with the base unit 1 or other handset units 2. Specifically, the communication unit 22 of the first handset unit 2A forms a link L with the base unit 1 and sends and receives messages to and from the base unit 1. The communication unit 22 of the second handset unit 2B forms a link L with another handset unit 2 and sends and receives messages to and from the other handset unit 2. The communication unit 22 includes, for example, a communication module having an RF-LSI for 920 MHz band communication.

The memory unit 23 stores various computer programs and various data. The various computer programs include, for example, a computer program for acquiring meter 3 measurement values at the scheduled meter reading date and time, and a computer program for performing wireless communication with a communication partner. The various data include, for example, data indicating the scheduled meter reading date and time, the communication start time T of the own device, the number of hops HP of the own device, the identification code ID of the own device, destination information of the own device, and destination information of the communication partner. For example, the memory unit 23 of the slave unit 2a stores data indicating the destination information of the master unit 1 and the slave unit 2b as destination information of the communication partner. The memory unit 23 includes, for example, semiconductor memory such as ROM, RAM, and flash memory.

The clock circuit 24 keeps track of the time. The control unit 25 obtains the current time based on the time kept by the clock circuit 24. The control unit 25 also obtains the current date and time based on the current time and calendar information. The date and time includes the date and time. The calendar information is stored in the memory unit 23.

The control unit 25 controls each element of the device. For example, the control unit 25 controls the connection unit 21, communication unit 22, memory unit 23, and clock circuit 24. Specifically, the control unit 25 has a processor such as a CPU or MPU. The processor controls each element of the device by executing a computer program stored in the memory unit 23. The control unit 25 and memory unit 23 may form a microcomputer.

The control unit 25 executes various processes. Specifically, the processor executes computer programs stored in the memory unit 23 to execute various processes. For example, when the scheduled meter reading date and time arrives, the control unit 25 acquires the measurement value of the meter 3 and stores it in the memory unit 23. Furthermore, when the communication start time T arrives, the control unit 25 starts the process of transmitting a measurement value message to the parent unit 1.

Next, the processing executed by the control unit 25 of the master unit 1 will be described with reference to Figures 1 to 5. Figure 4 is a flowchart showing the processing executed by the control unit 25 of the communication master unit 1 in this embodiment. In detail, Figure 4 shows the processing for setting the regular meter reading date and time and the communication start time T for each slave unit 2. Hereinafter, the processing for setting the regular meter reading date and time and the communication start time T for each slave unit 2 may be referred to as the "communication start time, etc. setting processing." As shown in Figure 4, the communication start time, etc. setting processing includes steps S1 to S4.

First, the first communication unit 11 of the parent unit 1 receives the scheduled meter reading setting message D1 from the center device 4 (step S1). The center device 4 sends the scheduled meter reading setting message D1 to the parent unit 1 when installing the parent unit 1 and five slave units 2a to 2e. The center device 4 also sends the scheduled meter reading setting message D1 to the parent unit 1 when installing additional slave units 2.

When the first communication unit 11 receives the scheduled meter reading setting message D1, the control unit 15 of the parent unit 1 determines the communication start time T for each child unit 2 (step S2). Specifically, the control unit 15 extracts the meter reading time t1 from the scheduled meter reading setting message D1. The control unit 15 also determines, for each child unit 2, the time interval X for starting communication with the parent unit 1 based on the hop count HP of each child unit 2. The control unit 15 also determines the communication order of each child unit 2 based on the identification code ID of each child unit 2. The control unit 15 then determines the communication start time T for each child unit 2 based on the meter reading time t1, the time interval X determined for each child unit 2, and the communication order of each child unit 2.

Once the control unit 15 of the base unit 1 determines the communication start time T for each handset 2, it notifies the center device 4 of the communication start time T for each handset 2 (step S3). Specifically, the control unit 15 transmits a message indicating the communication start time T for each handset 2 to the center device 4 via the first communication unit 11.

After notifying the center device 4 of the communication start time T for each slave 2, the control unit 15 of the master 1 sets the regular meter reading date and time and the communication start time T for each slave 2 (step S4), and ends the communication start time, etc. setting process. Specifically, the control unit 15 of the master 1 notifies each slave 2 of the regular meter reading date and time and the communication start time T. In more detail, the control unit 15 of the master 1 sends a message D2 indicating the regular meter reading date and time and the communication start time T to each slave 2 via the second communication unit 12. Hereinafter, the message D2 indicating the regular meter reading date and time and the communication start time T may be referred to as the "communication start time, etc. setting message D2."

When the communication unit 22 receives the communication start time setting message D2, the control unit 25 of each slave unit 2 extracts the scheduled meter reading date and time and the communication start time T from the communication start time setting message D2 and stores them in the memory unit 23.

Figure 5 is a flowchart showing the processing executed by the control unit 25 of the communication base unit 1 in this embodiment. In particular, Figure 5 shows an example of the details of step S4 of the communication start time setting process (Figure 4).

After notifying the center device 4 of the communication start time T for each slave device 2 (step S3 in FIG. 4), the control unit 15 of the master device 1 determines whether the regular meter reading date and time and the communication start time T have been set for all slave devices 2 (step S41). In other words, the control unit 15 determines whether there are any slave devices 2 for which the regular meter reading date and time and the communication start time T have not been set. Specifically, the control unit 15 determines whether the communication start time setting message D2 has been sent to all slave devices 2.

If the control unit 15 of the parent unit 1 determines that there are any slave units 2 remaining for which the regular meter reading date and time and communication start time T have not been set (No in step S41), it sets the regular meter reading date and time and communication start time T for one of the slave units 2 for which the regular meter reading date and time and communication start time T have not been set (step S42). In other words, the control unit 15 of the parent unit 1 sends a communication start time setting message D2 to one of the slave units 2 for which the regular meter reading date and time and communication start time T have not been set. As a result, the process returns to step S41. On the other hand, if the control unit 15 determines that the regular meter reading date and time and communication start time T have been set for all slave units 2 (Yes in step S41), the process shown in Figures 4 and 5 ends.

Next, we will explain the time interval X and communication start time T with reference to Figures 1 to 7. Figure 6 is a diagram showing an example of the time interval X, and Figure 7 is a diagram showing an example of the communication start time T.

As shown in FIG. 6 , the control unit 15 of the base unit 1 determines the time interval X for each slave unit 2 so that the larger the hop count HP of the slave unit 2, the longer the time interval X between the slave unit 2 and the slave unit 2 that starts communication after that slave unit 2. In this embodiment, the control unit 15 of the base unit 1 sets a first time interval X1 for the slave units 2 (slave units 2a and 2d) with a hop count HP of "1," a second time interval X2 for the slave units 2 (slave units 2b and 2e) with a hop count HP of "2," and a third time interval X3 for the slave unit 2 (slave unit 2c) with a hop count HP of "3." The first time interval X1 is smaller than the second time interval X2 and the third time interval X3 (X1 < X2, X3). The second time interval X2 is larger than the first time interval X1 and smaller than the third time interval X3 (X1 < X2 < X3). The third time interval X3 is greater than the first time interval X1 and the second time interval X2 (X3 > X1, X2).

As shown in Figure 7, the control unit 15 of the master unit 1 determines the communication start time T for each slave unit 2 based on the meter reading time t1, the communication order of each slave unit 2, and the time interval X set for each slave unit 2. In this embodiment, the communication order of each slave unit 2 is in the order of the identification code ID of each slave unit 2. In other words, the smaller the identification code ID, the earlier the communication order. In this embodiment, the communication order of the five slave units 2a to 2e is slave unit 2a, slave unit 2b, slave unit 2c, slave unit 2d, slave unit 2e.

The control unit 15 of the parent unit 1 sets the communication start time T (t21) of the child unit 2 (child unit 2a) that will start communicating first to the meter reading time t1. The control unit 15 of the parent unit 1 determines the communication start time T of the child unit 2 (child unit 2b) that will start communicating second based on the communication start time T (t21) set for the child unit 2 (child unit 2a) that will start communicating first and the time interval X (first time interval X1). Specifically, the control unit 15 of the parent unit 1 sets the communication start time T of the child unit 2b to time t22, which is delayed by the first time interval X1 from time t21.

Similarly, the control unit 15 of the base unit 1 sets the communication start time T of the handset 2c to time t23, which is delayed by the second time interval X2 from time t22. The control unit 15 of the base unit 1 sets the communication start time T of the handset 2d to time t24, which is delayed by the third time interval X3 from time t23. The control unit 15 of the base unit 1 sets the communication start time T of the handset 2e to time t25, which is delayed by the first time interval X1 from time t24.

In other words, the communication start time T (t22) of handset 2b indicates a time delayed from meter reading time t1 by the first time interval X1 (the time interval X set for handset 2a). The communication start time T (t23) of handset 2c indicates a time delayed from meter reading time t1 by the sum of the first time interval X1 and the second time interval X2 (the time interval X set for handset 2b). The communication start time T (t24) of handset 2d indicates a time delayed from meter reading time t1 by the sum of the first time interval X1, the second time interval X2, and the third time interval X3 (the time interval X set for handset 2c). The communication start time T (t25) of handset 2e indicates a time delayed from meter reading time t1 by the sum of the first time interval X1, the second time interval X2, the third time interval X3, and the first time interval X1 (the time interval X set for handset 2d).

Next, the master unit 1 of this embodiment will be described with reference to Figures 1 to 8. Figure 8 is a sequence diagram showing an example of the operation of the communication master unit 1 of this embodiment. In detail, Figure 8 shows the operation of the master unit 1 when setting the scheduled meter reading date and time and the communication start time T for each slave unit 2.

As shown in FIG. 8, when the master unit 1 receives the scheduled meter reading setting message D1 from the center device 4, it transmits a response message Re1 to the center device 4. Specifically, the control unit 15 of the master unit 1 creates a message (response message Re1) indicating that the scheduled meter reading setting message D1 has been received, and transmits the response message Re1 to the center device 4 via the first communication unit 11. The control unit 15 then determines the communication start time T for each slave unit 2, as described with reference to FIGS. 6 and 7. Then, as described with reference to FIG. 4, it notifies the center device 4 of the communication start time T for each slave unit 2 (step S3 in FIG. 4).

After notifying the center device 4 of the communication start time T for each slave 2, the master 1 sets the scheduled meter reading date and time and the communication start time T for each slave 2 in sequence. Specifically, the master 1 sets the scheduled meter reading date and time and the communication start time T for slave 2a, slave 2b, slave 2c, slave 2d, and slave 2e in that order.

In detail, the control unit 15 of the master unit 1 creates a communication start time setting message D21 indicating the scheduled meter reading date and time and the communication start time t21, and transmits the communication start time setting message D21 to the slave unit 2a via the second communication unit 12.

When the control unit 15 of the master unit 1 receives a response message Re21 from the slave unit 2a indicating that the communication start time setting message D21 has been received, the control unit 15 creates a communication start time setting message D22 indicating the scheduled meter reading date and time and the communication start time t22, and transmits the communication start time setting message D22 to the slave unit 2b via the second communication unit 12.

When the control unit 15 of the master unit 1 receives a response message Re22 from the slave unit 2b indicating that the communication start time setting message D22 has been received, the control unit 15 creates a communication start time setting message D23 indicating the scheduled meter reading date and time and the communication start time t23, and transmits the communication start time setting message D23 to the slave unit 2c via the second communication unit 12.

When the control unit 15 of the master unit 1 receives a response message Re23 from the slave unit 2c indicating that the communication start time setting message D23 has been received, the control unit 15 creates a communication start time setting message D24 indicating the scheduled meter reading date and time and the communication start time t24, and transmits the communication start time setting message D24 to the slave unit 2d via the second communication unit 12.

When the control unit 15 of the master unit 1 receives a response message Re24 from the slave unit 2d indicating that the communication start time setting message D24 has been received, the control unit 15 creates a communication start time setting message D25 indicating the scheduled meter reading date and time and the communication start time t25, and transmits the communication start time setting message D25 to the slave unit 2e via the second communication unit 12.

When the control unit 15 of the base unit 1 receives a response message Re25 from the handset 2e indicating that the communication start time setting message D25 has been received, the control unit 15 terminates the communication start time setting process.

Next, the master unit 1 of this embodiment will be described with reference to Figures 1 to 9. Figure 9 is a sequence diagram showing an example of the operation of the communication master unit 1 of this embodiment. In particular, Figure 9 shows the details of the operation of the master unit 1 when setting the scheduled meter reading date and time and the communication start time T for the slave units 2a and 2b.

As shown in FIG. 9, when communicating with handset 2a, the control unit 15 of base unit 1 performs initial communication with handset 2a. Initial communication is a process for forming link L, as described with reference to FIG. 1. When communicating with handset 2a, the control unit 15 of base unit 1 establishes a first link L1 (see FIG. 1) with handset 2a through initial communication. After the first link L1 is established, the control unit 15 of base unit 1 transmits a communication start time and other setting message D21 to handset 2a via the second communication unit 12.

The communication start time setting message D21 includes destination information for the slave 2a. After the control unit 25 of the slave 2a confirms that the destination information in the communication start time setting message D21 matches the destination of its own device, it extracts the regular meter reading date and time and the communication start time T from the communication start time setting message D21 and stores them in the memory unit 23.

When the control unit 15 of the base unit 1 receives the response message Re21 from the handset 2a, it releases (disconnects) the first link L1. The control unit 15 of the base unit 1 then executes initial communication with the handset 2a and establishes the first link L1. After establishing the first link L1, the control unit 15 of the base unit 1 sends a communication start time setting message D22 to the handset 2a via the second communication unit 12.

The communication start time setting message D22 contains destination information for handset 2b, and the control unit 25 of handset 2a executes initial communication with handset 2b based on the destination information in the communication start time setting message D22. As a result, a second link L2 (see Figure 1) is established between handset 2a and handset 2b. After the second link L2 is established, the control unit 25 of handset 2a transmits the communication start time setting message D22 to handset 2b via the communication unit 22.

When the control unit 25 of the handset 2b receives the communication start time setting message D22, it sends a response message Re22 to the handset 2a. The response message Re22 includes destination information for the base unit 1, and the control unit 25 of the handset 2a sends the response message Re22 to the base unit 1 based on the destination information in the response message Re22. After sending the response message Re22 to the base unit 1, the control unit 25 of the handset 2a releases (disconnects) the second link L2. When the control unit 15 of the base unit 1 receives the response message Re22 from the handset 2a, it releases (disconnects) the first link L1.

Note that the operation of the parent unit 1 when setting the regular meter reading date and time and communication start time T for the other slave units 2c to 2e is the same as the operation of the parent unit 1 when setting the regular meter reading date and time and communication start time T for slave units 2a and 2b, so a description of this will be omitted.

Next, the slave unit 2 will be described with reference to Figures 1 to 10. Figure 10 is a sequence diagram showing an example of the operation of the communication slave unit 2. In detail, Figure 10 shows the operation when each slave unit 2 sends a measurement value message to the master unit 1.

As shown in FIG. 10, the control unit 25 of handset 2a transmits a measurement value telegram D31 to the base unit 1 via the communication unit 22 when the current time becomes communication start time t21. The control unit 25 of handset 2b transmits a measurement value telegram D32 to the base unit 1 via the communication unit 22 when the first time interval X1 has elapsed since communication start time t21 and the current time becomes communication start time t22. The control unit 25 of handset 2c transmits a measurement value telegram D33 to the base unit 1 via the communication unit 22 when the second time interval X2 has elapsed since communication start time t22 and the current time becomes communication start time t23. The control unit 25 of handset 2d transmits a measurement value telegram D34 to the base unit 1 via the communication unit 22 when the third time interval X3 has elapsed since communication start time t23 and the current time becomes communication start time t24. When the first time interval X1 has elapsed since the communication start time t24 and the current time reaches the communication start time t25, the control unit 25 of the slave unit 2e transmits a measurement value telegram D35 to the master unit 1 via the communication unit 22.

After receiving measurement value telegrams D31 through D35 from all of slave units 2a through 2e, the control unit 15 of master unit 1 creates telegram D3 indicating the measurement values of each of meters 3a through 3e. It then transmits telegram D3 to the center device 4 via the first communication unit 11.

Next, the base unit 1 and the slave unit 2 will be described with reference to Figures 1 to 11. Figure 11 is a sequence diagram showing an example of the operation of the communication slave units 2a and 2b. In more detail, Figure 11 shows the details of the operation of the slave units 2a and 2b when transmitting measurement value messages.

As shown in FIG. 11, when communicating with the base unit 1, the control unit 25 of the handset 2a performs initial communication with the base unit 1. As a result, a first link L1 (see FIG. 1) is established between the handset 2a and the base unit 1. After the first link L1 is established, the control unit 25 of the handset 2a transmits a measurement value telegram D31 to the base unit 1 via the communication unit 22.

When the control unit 15 of the parent device 1 receives the measurement value telegram D31, it creates a response telegram Re31 indicating that the measurement value telegram D31 has been received and sends the response telegram Re31 to the child device 2a via the second communication unit 12. The response telegram Re31 includes destination information for the child device 2a, and the control unit 25 of the child device 2a confirms that the destination information in the response telegram Re31 matches the destination of its own device, and then releases (disconnects) the first link L1.

The measurement value telegram D31 includes destination information for the parent device 1. After the control unit 15 of the parent device 1 confirms that the destination information in the measurement value telegram D31 matches the destination of its own device, it extracts the measurement values from the measurement value telegram D31 and stores them in the memory unit 13.

When the first time interval X1 has elapsed since communication start time t21 and the current time reaches communication start time t22, the control unit 25 of handset 2b executes initial communication with handset 2a. As a result, a second link L2 (see Figure 1) is established between handset 2a and handset 2b. After the second link L2 is established, the control unit 25 of handset 2b transmits a measurement value telegram D32 to handset 2a via the communication unit 22.

Measurement value telegram D32 includes destination information for the parent unit 1, and the control unit 25 of the child unit 2a performs initial communication with the parent unit 1 based on the destination information in the measurement value telegram D32. As a result, a first link L1 is established. After the first link L1 is established, the control unit 25 of the child unit 2a transmits the measurement value telegram D32 to the parent unit 1 via the communication unit 22.

When the control unit 15 of the parent device 1 receives the measurement value message D32, it creates a response message Re32 indicating that the measurement value message D32 has been received, and sends the response message Re32 to the child device 2a via the second communication unit 12. The response message Re32 includes destination information for the child device 2b.

When the control unit 25 of the slave device 2a receives the response message Re32, it sends the response message Re32 to the slave device 2b and releases (disconnects) the first link L1. When the control unit 25 of the slave device 2b receives the response message Re32, it releases (disconnects) the second link L2.

In this embodiment, when the control unit 15 of the parent unit 1 receives a measurement value telegram from the child unit 2, it stores the time at which the measurement value telegram was received in the memory unit 13. Specifically, when the control unit 15 of the parent unit 1 receives measurement value telegram D31, it stores reception time t31, which is the time at which measurement value telegram D31 was received, in the memory unit 13. Similarly, when the control unit 15 of the parent unit 1 receives measurement value telegrams D32 to D35, it stores reception times t32 to t35, which are the times at which measurement value telegrams D32 to D35 were received, in the memory unit 13.

Note that the operation of sub-units 2c to 2d when transmitting measurement value messages is the same as that of sub-units 2a and 2b, so a detailed explanation will be omitted.

Next, the base unit 1 will be described with reference to Figures 1 to 12. Figure 12 is a flowchart showing the processing executed by the control unit 15 of the communication base unit 1 of this embodiment. In detail, Figure 12 shows the processing for resetting the communication start time T. Hereinafter, the processing for resetting the communication start time T may be referred to as the "communication start time resetting processing." As shown in Figure 12, the communication start time resetting processing includes steps S11 to S15.

As described with reference to FIG. 11, the control unit 15 of the base unit 1 stores the reception times (reception times t31 to t35) of each measurement value telegram (measurement value telegram D31 to measurement value telegram D35) in the memory unit 13 (step S11). Specifically, each time the control unit 15 of the base unit 1 receives a measurement value telegram, it acquires the current time from the clock circuit 14 as the reception time. Then, it stores the time acquired from the clock circuit 14 in the memory unit 13 as the reception time.

The control unit 15 of the base unit 1 receives the measurement value telegrams from all the slave units 2 (slave units 2a to 2e) and stores the reception time of each measurement value telegram (measurement value telegram D31 to measurement value telegram D35) in the memory unit 13. Then, it calculates the communication time DL for each slave unit 2 (step S12). Here, the communication time DL indicates the difference between the communication start time T and the reception time.

The control unit 15 of the base unit 1 determines the communication start time T for each handset 2 based on the communication time DL of each handset 2 (step S13). Specifically, the control unit 15 determines the communication start time T for each handset 2 so that the handset 2 with the longest communication time DL starts communication with the base unit 1 last. In this embodiment, the control unit 15 of the base unit 1 updates the communication start time T for each handset 2 so that communication with the base unit 1 begins in order of shortest communication time DL.

Once the control unit 15 of the base unit 1 determines the communication start time T for each handset 2, it notifies the center device 4 of the communication start time T for each handset 2 (step S14), similar to step S3 in FIG. 4.

After notifying the center device 4 of the communication start time T for each handset 2, the control unit 15 of the base unit 1 sets the communication start time T for each handset 2 (step S15), similar to step S4 in FIG. 4, and ends the communication start time resetting process.

Next, the communication time DL and the updated communication start time T will be explained with reference to Figures 1 to 14. Figure 13 shows an example of the communication time DL, and Figure 14 shows an example of the updated communication start time T.

As shown in FIG. 13, communication time DL1 for handset 2a indicates the difference between communication start time t21 and reception time t31. Communication time DL2 for handset 2b indicates the difference between communication start time t22 and reception time t32. Communication time DL3 for handset 2c indicates the difference between communication start time t23 and reception time t33. Communication time DL4 for handset 2d indicates the difference between communication start time t24 and reception time t34. Communication time DL5 for handset 2e indicates the difference between communication start time t25 and reception time t35. In this embodiment, communication times DL1 and DL4 for handset 2a and 2d are the shortest, communication times DL2 and DL5 for handset 2b and 2e are next shortest, and communication time DL3 for handset 2c is the longest.

As shown in FIG. 14, the control unit 15 of the base unit 1 determines the communication start time T for each handset 2 so that communication with the base unit 1 begins in ascending order of communication time DL. In this embodiment, the control unit 15 determines the communication start time T for each handset 2 so that communication with the base unit 1 begins in the following order: handset 2a, handset 2d, handset 2b, handset 2e, and handset 2c. Note that the method for determining the communication order for handset 2 with the same communication time DL is arbitrary. For example, the control unit 15 may determine the communication start time T for handset 2 with the same communication time DL so that communication begins in the order of identification code ID.

In this embodiment, the control unit 15 of the master unit 1 sets the communication start time T (t41) of the slave unit 2a to the meter reading time t1. The control unit 15 of the master unit 1 sets the communication start time T of the slave unit 2d to time t42, which is delayed by the first time interval X1 from time t41. The control unit 15 of the master unit 1 sets the communication start time T of the slave unit 2b to time t43, which is delayed by the first time interval X1 from time t42. The control unit 15 of the master unit 1 sets the communication start time T of the slave unit 2e to time t44, which is delayed by the second time interval X2 from time t43. The control unit 15 of the master unit 1 sets the communication start time T of the slave unit 2c to time t45, which is delayed by the second time interval X2 from time t44.

Accordingly, according to this embodiment, the waiting time of the third time interval X3, which is the maximum time interval X, can be eliminated from the time required for all handset devices 2 to complete communication. This further shortens the time required for all handset devices 2 to complete communication.

Next, the slave unit 2 will be described with reference to Figures 1 to 15. Figure 15 is a sequence diagram showing an example of the operation of the communication slave unit 2. In detail, Figure 15 shows the operation when each slave unit 2 sends a measurement value message to the master unit 1 after the communication start time T is reset (updated).

As shown in FIG. 15, the control unit 25 of handset 2a transmits a measurement value telegram D31 to the base unit 1 via the communication unit 22 when the current time becomes communication start time t41. The control unit 25 of handset 2d transmits a measurement value telegram D34 to the base unit 1 via the communication unit 22 when the first time interval X1 has elapsed since communication start time t41 and the current time becomes communication start time t42. The control unit 25 of handset 2b transmits a measurement value telegram D32 to the base unit 1 via the communication unit 22 when the first time interval X1 has elapsed since communication start time t42 and the current time becomes communication start time t43. The control unit 25 of handset 2e transmits a measurement value telegram D35 to the base unit 1 via the communication unit 22 when the second time interval X2 has elapsed since communication start time t43 and the current time becomes communication start time t44. When the second time interval X2 has elapsed since the communication start time t44 and the current time reaches the communication start time t45, the control unit 25 of the slave unit 2c transmits a measurement value telegram D33 to the master unit 1 via the communication unit 22.

After receiving measurement value telegrams D31 through D35 from all of slave units 2a through 2e, the control unit 15 of master unit 1 transmits telegram D3 to the center device 4.

As described above with reference to Figures 1 to 15, this embodiment can shorten the time required for all communication devices 2 to complete communication, compared to a configuration in which the time interval for the communication start time T of each communication device 2 is uniformly set to the same time interval X. Furthermore, this embodiment can rearrange the communication order of each communication device 2 based on the communication time DL of each communication device 2. As a result, the time required for all communication devices 2 to complete communication can be further shortened.

Embodiments of the present invention have been described above with reference to the drawings (Figs. 1 to 15). However, the present invention is not limited to the above embodiments and can be implemented in various forms without departing from the spirit of the present invention. Furthermore, the multiple components disclosed in the above embodiments can be modified as appropriate. For example, some of the components shown in one embodiment may be added to the components of another embodiment, or some of the components shown in one embodiment may be deleted from the embodiment.

The drawings primarily show each component in a schematic manner to facilitate understanding of the invention, and the thickness, length, number, spacing, etc. of each component shown may differ from the actual configuration due to the convenience of creating the drawings. Furthermore, the configuration of each component shown in the above embodiment is merely an example and is not particularly limited, and it goes without saying that various modifications are possible within the scope of not substantially departing from the effects of the present invention.

For example, in the embodiment described with reference to Figures 1 to 15, the slave unit 2 and the meter 3 are connected by wire PL, but the slave unit 2 and the meter 3 may also be connected wirelessly.

In addition, in the embodiment described with reference to Figures 1 to 15, the communication start time T (t21) of the slave unit 2 (slave unit 2a) that first starts communication was set to the meter reading time t1, but the communication start time T (t21) of the slave unit 2 (slave unit 2a) that first starts communication may also be set to a time that is later than the meter reading time t1.

In addition, in the embodiment described with reference to Figures 1 to 15, the meter 3 is connected to the communication handset 2, but the present invention can also be applied to a communication system equipped with a meter that has the functionality of the communication handset 2.

The present invention is useful in the field of wireless communications.

1: Communication base unit 2, 2a to 2e: Communication slave unit 3, 3a to 3e: Meter 4: Center device 12: Second communication unit 13: Memory unit 15: Control unit HP: Number of hops L: Link L1: First link L2: Second link L3: Third link L4: Fourth link L5: Fifth link T, t21 to t25, t41 to t45: Communication start time X: Time interval X1: First time interval X2: Second time interval X3: Third time interval t1: Meter reading time (set time)
t31 to t35: Reception time

Claims (5)

A communication base unit that communicates with a plurality of communication slave units,
The plurality of communication slave units include:
a first communication slave unit that directly communicates with the communication master unit;
a second communication slave device that communicates with the communication master device via at least one other communication slave device among the plurality of communication slave devices,
each of the plurality of communication slave units communicates with the communication master unit via at least one link established between the communication slave units and the communication master unit;
the hop number indicating the number of links of the first communication slave device indicates 1,
the number of hops of the second communication terminal increases in accordance with the number of the other communication terminals interposed between the second communication terminal and the communication base terminal,
the communication base station includes a setting unit that sets a communication start time for each of the plurality of communication slave stations based on the number of hops for each of the plurality of communication slave stations ;
the setting unit determines, for each of the plurality of communication slave devices, a time interval for starting communication with the communication master device based on the number of hops of each of the plurality of communication slave devices, and sets the communication start time of each of the plurality of communication slave devices based on the time interval;
The time interval is:
a first time interval set after the communication slave device having the first hop number starts communication;
a second time interval provided after a communication slave device having a second hop number greater than the first hop number starts communication;
Including,
the setting unit determines the time interval such that the second time interval is greater than the first time interval;
the communication start time indicates a time when the communication slave device starts communication for transmitting the meter measurement value to the communication master device,
an acquisition unit that acquires each reception time, which is a time when the measurement value is received from each of the plurality of communication slave devices;
a storage unit that stores the reception times acquired by the acquisition unit;
Further provided with
The setting unit updates the communication start time of each of the plurality of communication slave devices based on the reception time . a communication unit that communicates with a center device and receives the set time from the center device;
The communication base unit according to claim 1 , wherein the setting unit sets the communication start time for each of the plurality of communication terminals based on the set time and the time interval. The communication base unit according to claim 1 or claim 2, wherein the setting unit updates the communication start time of each of the plurality of communication base units so that the communication base unit with the largest difference between the communication start time and the reception time starts communication with the communication base unit last. The communication base unit according to any one of claims 1 to 3, wherein the setting unit updates the communication start time of each of the plurality of communication slave units so as to communicate with the communication base unit in order of the smallest difference between the communication start time and the reception time. The communication master unit according to claim 1 , wherein the setting unit further sets a time at which each of the communication slave units acquires the measured value of the meter.