Communication terminal

Abstract

To provide a communication terminal capable of suppressing an unwanted communication.SOLUTION: A communication terminal 22a2 performs communication with a management device 11 via another communication terminal 22a1, 22a3, 22b1, or 22b2. The communication terminal 22a2 comprises a communication part 223 and a processing part 221. The communication part 223 performs communication with the other communication terminals 22a1, 22a3, 22b1, and 22b2. The processing part 221 determines whether or not the communication with the management device 11 is failed. In the case where it is determined that the communication with the management device 11 is failed, the processing part is transmitted to an origination restriction mode restricting the communication with the first communication terminal 22a3 opposite to the management device 11 side in a predetermined basic communication route Ra. The other terminals 22a1, 22a3, 22b1, and 22b2 contain the first communication terminal 22a3.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a communication terminal.

Background Art

[0002] Patent Document 1 discloses a plurality of child nodes, a parent node, and a monitoring center. The child nodes acquire sensor data. The parent node and the child nodes communicate with each other using specific low-power radio. The parent node collects sensor data from the child nodes. The parent node and the monitoring center are connected via a public line. The parent node transmits the sensor data collected from the child nodes to the monitoring center.

[0003] The plurality of child nodes include child nodes that can be directly wirelessly connected to the parent node and child nodes that cannot be directly wirelessly connected to the parent node. The child nodes that cannot be directly wirelessly connected to the parent node use other child nodes as relay nodes to transmit sensor data to the parent node.

[0004] The child nodes wirelessly connected to the parent node via a relay node, when the relay node fails, select other child nodes as relay nodes and transmit sensor data to the parent node using a detour relay path. Hereinafter, the child nodes directly wirelessly connected to the relay node are referred to as "first child nodes". Also, the child nodes wirelessly connected to the parent node using the first child node as a relay node are referred to as "second child nodes". The second child node is a communication terminal on the side opposite to the monitoring center (management device) side with respect to the first child node.

[0005] In a wireless communication system including child nodes that cannot be directly wirelessly connected to the parent node, when the relay node fails, the first child node searches for a detour relay node.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, even when the detour relay node fails, the first child node (communication terminal) communicates with the second child node. As a result, unnecessary communication is performed.

[0008] The present invention has been made in view of the above problems, and an object thereof is to provide a communication terminal capable of suppressing unnecessary communication.

Means for Solving the Problems

[0009] The communication terminal of the present invention communicates with a management device via another communication terminal. The communication terminal includes a communication unit and a processing unit. The communication unit communicates with the other communication terminal. The processing unit determines whether communication with the management device has failed, and when it is determined that communication with the management device has failed, transitions to a transmission restriction mode that restricts communication with a first communication terminal on the side opposite to the management device side in a predetermined basic communication route. The other communication terminal includes the first communication terminal.

Effects of the Invention

[0010] According to the communication terminal according to the present invention, unnecessary communication can be suppressed.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the communication terminal according to the present invention will be described with reference to the drawings (FIGS. 1 to 8). However, the present invention is not limited to the following embodiments, and can be implemented in various aspects without departing from the gist thereof. Note that descriptions of overlapping parts may be omitted as appropriate. Also, in the figures, the same or corresponding parts are denoted by the same reference numerals and the description will not be repeated.

[0013] First, the communication system 100 will be described with reference to FIG. 1. FIG. 1 is a diagram showing the communication system 100. In the present embodiment, the communication system 100 is a telemeter system. Hereinafter, the communication system 100 may be referred to as the "telemeter system 100". As shown in FIG. 1, the telemeter system 100 includes a center device 11, a master unit 21, and a plurality of slave units 22.

[0014] The center device 11 is communicably connected to the wide area wireless network N1 via the center-side network control device 12. The center-side network control device 12 is communicably connected to the master unit 21 via the wide area wireless network N1. The center-side network control device 12 is provided, for example, in the public network of a communication carrier. The center-side network control device 12 controls the communication between the master unit 21 and the center device 11 via the wide area wireless network N1.

[0015] The wide-area wireless network N1 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.

[0016] The master device 21 and the slave devices 22 are communication terminals. The master device 21 is communicably connected to a plurality of slave devices 22 via a short-range wireless network N2. The frequency band of the short-range wireless network N2 is, for example, the 920 MHz band. More specifically, the master device 21 and the slave devices 22 communicate by specific low-power radio (SLR). Hereinafter, communication by SLR may be referred to as "SLR communication".

[0017] The communication partner of the master device 21 is predetermined. Similarly, the communication partner of the slave device 22 is predetermined. Therefore, the communication route between the master device 21 and each slave device 22 is predetermined. Hereinafter, the predetermined communication route may be referred to as the "basic communication route R".

[0018] Specifically, the master device 21 stores pairing information. The pairing information stored in the master device 21 defines the communication partner of the master device 21. The master device 21 communicates with the communication terminal defined by the pairing information. Similarly, the slave device 22 stores pairing information. The pairing information stored in the slave device 22 defines the communication partner of the slave device 22. The slave device 22 communicates with the communication terminal defined by the pairing information. Hereinafter, the communication partner defined by the pairing information may be referred to as the "paired terminal".

[0019] In the example shown in FIG. 1, the plurality of slave devices 22 include eight slave devices 22a1 to 22a3, 22b1 to 22b2, and 22c1 to 22c3. Also, in the example shown in FIG. 1, the communication system 100 includes three basic communication routes R (first basic communication route Ra, second basic communication route Rb, and third basic communication route Rc).

[0020] The first basic communication route Ra includes the master unit 21 and three slave units 22a1 to 22a2. The second basic communication route Rb includes the master unit 21 and two slave units 22b1 and 22b2. The third basic communication route Rc includes the master unit 21 and three slave units 22c1 to 22c3.

[0021] Specifically, the edge connection terminals of the master unit 21 are the slave units 22a1, 22b1, and 22c1. The edge connection terminals of the slave unit 22a1 are the master unit 21 and the slave unit 22a2. The edge connection terminals of the slave unit 22a2 are the slave unit 22a1 and the slave unit 22a3. The edge connection terminal of the slave unit 22a3 is the slave unit 22a2. The edge connection terminals of the slave unit 22b1 are the master unit 21 and the slave unit 22b2. The edge connection terminal of the slave unit 22b2 is the slave unit 22b1. The edge connection terminals of the slave unit 22c1 are the master unit 21 and the slave unit 22c2. The edge connection terminals of the slave unit 22c2 are the slave unit 22c1 and the slave unit 22c3. The edge connection terminal of the slave unit 22c3 is the slave unit 22c2.

[0022] A meter 23 (see FIG. 5) is connected to the slave unit 22. The meter 23 is installed for each consumer such as a private house, a company, and various facilities. The meter 23 is a measuring device. The measurement target of the meter 23 is, for example, the usage amount of resources such as gas, water, or electricity. The meter 23 measures the usage amount of resources such as gas, water, or electricity and outputs the measurement result to the slave unit 22. The slave unit 22 transmits the measurement result obtained from the meter 23 to the center device 11. Specifically, the slave unit 22 creates a telegram D1 (data) including the measurement result and transmits the created telegram D1 to the center. Hereinafter, the telegram D1 to the center may be referred to as the "telegram D1 to the center".

[0023] The telegram D1 to the center is transmitted to the master unit 21 along the basic communication route R. The master unit 21 transmits the telegram D1 to the center transmitted from the slave unit 22 to the master unit 21 to the center device 11 via the wide area wireless network N1 and the center side network control device 12.

[0024] For example, the slave unit 22a3 transmits the center-directed telegram D1 to the slave unit 22a2. The center-directed telegram D1 transmitted from the slave unit 22a3 to the slave unit 22a2 is transmitted to the master unit 21 along the first basic communication route Ra. Specifically, the center-directed telegram D1 is transmitted from the slave unit 22a3 to the master unit 21 via the slave unit 22a2 and the slave unit 22a1 in this order.

[0025] Specifically, after the slave unit 22 executes a connection process to establish a communication connection with the pairing terminal, the slave unit 22 transmits the center-directed telegram D1 to the pairing terminal. More specifically, the slave unit 22 transmits a connection request signal to the pairing terminal. The pairing terminal that has received the connection request signal transmits an approval signal (Ack signal) to the slave unit 22 that is the source of the connection request signal. As a result, a communication connection is established between the slave unit 22 and the pairing terminal.

[0026] For example, when the center-directed telegram D1 is transmitted from the slave unit 22a3 to the master unit 21 along the first basic communication route Ra, first, after the slave unit 22a3 establishes a communication connection with the slave unit 22a2, the slave unit 22a3 transmits the center-directed telegram D1 to the slave unit 22a2. When the slave unit 22a2 receives the center-directed telegram D1, after establishing a communication connection with the slave unit 22a1, the slave unit 22a2 transmits the center-directed telegram D1 to the slave unit 22a1. When the slave unit 22a1 receives the center-directed telegram D1, after establishing a communication connection with the master unit 21, the slave unit 22a1 transmits the center-directed telegram D1 to the master unit 21.

[0027] The center device 11 acquires measurement results from the center-directed telegram D1 received via the wide area wireless network N1 and the center-side network control device 12, and stores the acquired measurement results for each meter 23 (see FIG. 5). More specifically, the center device 11 stores the measurement results of the meter 23 for each consumer. The center device 11 includes an information processing device such as a server or a personal computer, for example. When the meter 23 is a gas meter, for example, the center device 11 is managed by the utility that supplies the gas. The center device 11 is an example of a management device.

[0028] When the center device 11 receives the center-directed telegram D1, it transmits a slave unit-directed telegram D2 addressed to the slave unit 22 that is the source of the center-directed telegram D1 to the master unit 21 via the center-side network control device 12 and the wide-area wireless network N1. The slave unit-directed telegram D2 is a response telegram indicating that the center device 11 has received the center-directed telegram D1. Hereinafter, the slave unit 22 that is the destination of the slave unit-directed telegram D2 may be referred to as the "destination slave unit 22".

[0029] When the master unit 21 receives the slave unit-directed telegram D2 from the center device 11, it transmits the slave unit-directed telegram D2 to the destination slave unit 22. Specifically, the slave unit-directed telegram D2 is transmitted from the master unit 21 to the destination slave unit 22 along the basic communication route R.

[0030] For example, when the destination of the slave unit-directed telegram D2 is the slave unit 22a3, the slave unit-directed telegram D2 is transmitted from the master unit 21 to the slave unit 22a3 along the first basic communication route Ra. Specifically, the master unit 21 transmits the slave unit-directed telegram D2 to the slave unit 22a1. The slave unit 22a1 transmits the slave unit-directed telegram D2 to the slave unit 22a2. The slave unit 22a2 transmits the slave unit-directed telegram D2 to the slave unit 22a3. When the slave unit-directed telegram D2 is transmitted from the master unit 21 to the destination slave unit 22, the connection process is not executed. This is because the communication connection was established when the center-directed telegram D1 was transmitted.

[0031] Subsequently, with reference to FIGS. 2 and 3, the detour route search process executed by the slave unit 22 will be described. FIG. 2 is a diagram showing an example of a detour route. The slave unit 22 executes a detour route search process when it cannot establish a communication connection with the edge group terminal. The detour route search process is a process of searching for a slave unit 22 with which the own unit can communicate from among the slave units 22 other than the edge group terminal. Hereinafter, the detour route search process will be described using the slave unit 22a2 as an example.

[0032] As already described, when establishing a communication connection with the slave device 22a1, the slave device 22a2 transmits a connection request signal addressed to the slave device 22a1. More specifically, the slave device 22a2 emits radio waves including a connection request signal addressed to the slave device 22a1. These radio waves are received by the slave devices 22 within the communication range of the slave device 22a2. Therefore, the slave devices 22 not included in the first basic communication route Ra also receive the connection request signal addressed to the slave device 22a1. For example, the communication distance of the ultra-small wireless communication is 1 m or more and 1000 m or less. In the examples shown in FIGS. 1 and 2, the slave devices 22b1 and 22b2 receive the connection request signal addressed to the slave device 22a1.

[0033] When the slave device 22b1 receives a connection request signal addressed to the slave device 22a1 from the slave device 22a2, it transmits a response signal including its own (slave device 22b1) identification information to the slave device 22a2. Similarly, the slave device 22b2 transmits a response signal including its own (slave device 22b2) identification information to the slave device 22a2. The response signal is radio waves. The response signal is, for example, a beacon signal.

[0034] When the slave device 22a2 receives a response signal from the slave device 22b1, it acquires and stores the identification information of the slave device 22b1 from the response signal. Similarly, the slave device 22a2 stores the identification information of the slave device 22b2. Further, when receiving the response signal, the slave device 22a2 acquires and stores the electric field strength value of the response signal (radio waves). Hereinafter, the slave device 22 that has transmitted the response signal may be described as a "detour candidate terminal". The detour candidate terminal is an example of a "communication terminal not included in the basic communication route".

[0035] If the slave device 22a2 does not receive an approval signal from the slave device 22a1 during the first timeout period after transmitting the connection request signal, it determines that the establishment of the communication connection has failed. When the slave device 22a2 determines that the establishment of the communication connection has failed, it executes a detour route search process to determine one of the detour candidate terminals as the communication partner.

[0036] For example, the slave unit 22a2 may determine one of the detour candidate terminals as the communication partner based on the electric field strength value of the response signal received from the detour candidate terminals. Specifically, the slave unit 22a2 determines the detour candidate terminal with the largest electric field strength value of the response signal as the communication partner. Hereinafter, the detour candidate terminal determined as the communication partner may be described as the "detour terminal". The detour terminal is an example of a "communication terminal not included in the basic communication route".

[0037] When the slave unit 22a2 determines the detour terminal, it establishes a communication connection with the detour terminal. As a result, a detour route is formed between the slave unit 22a2 and the detour terminal. For example, as shown in FIG. 2, when the slave unit 22a2 determines the slave unit 22b1 as the communication partner, it establishes a communication connection with the slave unit 22b1. As a result, a detour route Rd1 is formed between the slave unit 22a2 and the slave unit 22b1.

[0038] When the slave unit 22a2 establishes a communication connection with the detour terminal, it transmits the center-directed message D1 to the detour terminal. That is, the center-directed message D1 is transmitted to the detour terminal along the detour route. For example, as shown in FIG. 2, the slave unit 22a2 forms the detour route Rd1 and transmits the center-directed message D1 to the slave unit 22b1.

[0039] The center-directed message D1 transmitted to the slave unit 22b1 is transmitted from the slave unit 22b1 to the master unit 21 along the second basic communication route Rb. Specifically, after the slave unit 22b1 establishes a communication connection with the master unit 21, it transmits the center-directed message D1 to the master unit 21.

[0040] As already described, the master unit 21 transmits the center-directed message D1 to the center device 11 via the wide area wireless network N1 and the center-side network control device 12. When the center device 11 receives the center-directed message D1, it transmits the slave-directed message D2 to the master unit 21 via the center-side network control device 12 and the wide area wireless network N1. The slave-directed message D2 is transmitted to the slave unit 22a2 via the second basic communication route Rb and the detour route Rd1.

[0041] If the slave unit 22a2 fails to receive the slave unit-destined message D2 during the second timeout period after transmitting the center-destined message D1, it stores the non-permission information in association with the identification information of the current detour terminal. The non-permission information indicates that communication with the center device 11 has failed. The non-permission information is, for example, a flag.

[0042] FIG. 3 is a diagram showing another example of a detour route. When the slave unit 22a2 fails again to establish a communication connection with the slave unit 22a1, it executes a detour route search process based on the response signal and the non-permission information, and determines another one of the detour candidate terminals as the communication partner (detour terminal). For example, the slave unit 22a2 may determine the detour candidate terminal with the next largest received field strength value of the response signal as the next communication partner (detour terminal). In the example shown in FIG. 3, the slave unit 22a2 determines the slave unit 22b2 as the next communication partner (detour terminal) and establishes a communication connection with the slave unit 22b2. As a result, a detour route Rd2 is formed between the slave unit 22a2 and the slave unit 22b2.

[0043] Subsequently, the transmission restriction mode will be described with reference to FIG. 4. FIG. 4 is a diagram showing the transmission restriction terminal of the present embodiment. The transmission restriction terminal indicates a communication terminal that has transitioned to the transmission restriction mode. Hereinafter, the transmission restriction mode will be described by taking the slave unit 22 as an example. In the example shown in FIG. 4, the slave unit 22a2 is the transmission restriction terminal.

[0044] When the communication between the slave unit 22 and the center device 11 fails, the slave unit 22 transitions to the transmission restriction mode. In the present embodiment, the slave unit 22 transitions to the transmission restriction mode when the number of times of communication failure with the center device 11 reaches a specified number of times. Hereinafter, the number of times of communication failure with the center device 11 may be referred to as the "NG count".

[0045] Specifically, the slave unit 22 executes a determination process for determining whether communication with the center device 11 has failed. When it is determined that communication with the center device 11 has failed, the NG count is incremented by one.

[0046] Specifically, when the slave unit 22 fails to establish a communication connection with the edge group terminal on the center device 11 side and is unable to receive the message D2 addressed to the slave unit via the detour route, it determines that the communication with the center device 11 has failed and increments the NG count by one. Also, when the slave unit 22 fails to establish a communication connection with the edge group terminal on the center device 11 side and there is no detour route, it determines that the communication with the center device 11 has failed and increments the NG count by one. Here, the absence of a detour route includes not only the absence of detour candidate terminals but also the inability to receive the message D2 addressed to the slave unit on all detour routes. In the following description, the edge group terminal on the center device 11 side may be referred to as the "upper terminal".

[0047] For example, the upper terminal of the slave unit 22a2 (the edge group terminal on the center device 11 side with respect to the slave unit 22a2) is the slave unit 22a1. Also, the detour candidate terminals of the slave unit 22a2 include the slave units 22b1 and 22b2. When the slave unit 22a2 fails to establish a communication connection with the slave unit 22a1 and is unable to receive the message D2 addressed to the slave unit via the slave unit 22b1 (detour route Rd1) or the slave unit 22b2 (detour route Rd2), it increments the NG count by one. Also, when the slave unit 22a2 fails to establish a communication connection with the slave unit 22a1 and the non - permission information is associated and stored in the identification information of both the slave units 22b1 and 22b2, it increments the NG count by one.

[0048] Note that the specified count for the NG count can be set to any value. The specified count may be one time or multiple times. For example, the specified count may be set to a value corresponding to the number of detour candidate terminals. Specifically, when the number of detour candidate terminals is two, the specified count may be three times or four or more times. Also, when the number of detour candidate terminals is zero, the specified count may be one time or two or more times.

[0049] The determination process is executed when the slave unit 22 transmits a center-directed telegram D1 including the measurement results obtained from the meter 23 (see FIG. 5) connected to the own unit. Further, the determination process is executed in response to the slave unit 22 establishing a communication connection with the edge unit terminal on the side opposite to the center device 11 side. For example, for the slave unit 22a2, the edge unit terminal on the side opposite to the center device 11 side is the slave unit 22a3. Therefore, the slave unit 22a2 executes the determination process in response to establishing a communication connection with the slave unit 22a3. Hereinafter, the case where the slave unit 22 transmits the center-directed telegram D1 including the measurement results obtained from the meter 23 connected to the own unit may be described as "self-transmission". Also, the edge unit terminal on the side opposite to the center device 11 side may be described as the "lower-stage terminal".

[0050] When the slave unit 22 transitions to the transmission restriction mode, it restricts communication with the lower-stage terminal. Specifically, the slave unit 22 (transmission restriction terminal) restricts the transmission of the approval signal. As a result, the lower-stage terminal executes a detour route search process.

[0051] For example, as shown in FIG. 4, when the slave unit 22a2 transitions to the transmission restriction mode, even if it receives a connection request signal from the slave unit 22a3, it does not transmit an approval signal. As a result, the slave unit 22a3 (lower-stage terminal) executes a detour route search process and forms a detour route Rd3 with the slave unit 22c3. Therefore, when the slave unit 22a3 does not receive an approval signal from the slave unit 22a2 during the first timeout period after transmitting the connection request signal, it can establish a communication connection with the slave unit 22c3 and transmit the center-directed telegram D1 to the slave unit 22c3. As a result, the center-directed telegram D1 is transmitted from the slave unit 22c3 to the master unit 21 along the third basic communication route Rc.

[0052] In this embodiment, the slave unit 22 (transmission control terminal) further controls its own transmission. That is, the slave unit 22 (transmission control terminal) controls the transmission of the center-directed telegram D1 including the measurement result obtained from the meter 23 (see FIG. 5) connected to its own unit. Further, the slave unit 22 (transmission control terminal) controls the transmission of the response signal. For example, when the slave unit 22b1 transitions to the transmission control mode, even if it receives a connection request signal from the slave unit 22a2, it does not transmit a response signal.

[0053] Note that the slave unit 22 (transmission control terminal) may cancel the transmission control mode in response to receiving a signal from the upper-stage terminal (the edge-set terminal on the center device 11 side with respect to the transmission control terminal). Alternatively, the slave unit 22 (transmission control terminal) may cancel the transmission control mode in response to receiving a cancellation signal from the center device 11 via the upper-stage terminal. Here, the cancellation signal is a signal for instructing the cancellation of the transmission control mode.

[0054] Subsequently, the master unit 21 will be described. Similar to the slave unit 22, when the communication with the center device 11 fails, the master unit 21 transitions to the transmission control mode. In this embodiment, when the number of NG times reaches the specified number, the master unit 21 transitions to the transmission control mode.

[0055] Specifically, the master unit 21 executes the determination process in the same manner as the slave unit 22. When it is determined that the communication with the center device 11 has failed, the number of NG times is increased by one.

[0056] Specifically, when the master unit 21 cannot establish a communication connection with the communication terminal on the center device 11 side, it determines that the communication with the center device 11 has failed and increases the number of NG times by one. Further, when the master unit 21 cannot receive the telegram D2 addressed to the slave unit, it determines that the communication with the center device 11 has failed and increases the number of NG times by one. Note that the communication terminal on the center device 11 side with respect to the master unit 21 is, for example, a base station forming the wide-area wireless network N1 or the center-side network control device 12.

[0057] The determination process is executed in response to the master device 21 establishing a communication connection with the lower terminal (the edge group terminal on the side opposite to the center device 11 side). In the example shown in FIG. 1, the determination process is executed in response to the master device 21 establishing a communication connection with the slave device 22a1, the slave device 22b1, or the slave device 22c1.

[0058] When the master device 21 transitions to the transmission restriction mode, it restricts communication with the lower terminal in the same manner as the slave device 22. Specifically, the master device 21 (the transmission restriction terminal) restricts the transmission of the approval signal.

[0059] Note that the master device 21 may release the transmission restriction mode in response to receiving a signal via the wide area wireless network N1. Alternatively, the master device 21 may release the transmission restriction mode in response to receiving a release signal from the center device 11.

[0060] As described above with reference to FIGS. 1 to 4, the master device 21 and the slave device 22 transition to the transmission restriction mode when communication with the center device 11 fails.

[0061] Subsequently, the configuration of the slave device 22 of the present embodiment will be described with reference to FIGS. 1 to 5. FIG. 5 is a block diagram showing the configuration of the slave device 22 of the present embodiment. As shown in FIG. 5, the slave device 22 includes a control unit 221, a storage unit 222, an N2 communication unit 223, and a connection unit 224. The control unit 221 is an example of the processing unit of the present invention. The N2 communication unit 223 is an example of the communication unit of the present invention.

[0062] The N2 communication unit 223 performs wireless communication with other communication terminals. The N2 communication unit 223, for example, as described with reference to FIGS. 1 to 4, establishes a communication connection with an edge group terminal or a detour terminal, and transmits and receives a connection request signal, an approval signal, a center-destined message D1 (measurement result), a slave device-destined message D2, and a response signal between the edge group terminal or the detour terminal. The N2 communication unit 223 includes, for example, a communication module having an RF-LSI for 920 MHz band communication.

[0063] Specifically, the N2 communication unit 223 has an antenna (not shown). The N2 communication unit 223 transmits and receives a radio signal (radio wave) through the antenna. The N2 communication unit 223 converts (decodes) the received radio signal into a signal that can be processed by the control unit 221 and outputs it to the control unit 221. Further, the N2 communication unit 223 converts the signal output from the control unit 221 to the N2 communication unit 223 into a signal compliant with the wireless communication method of the narrow area wireless network N2 (for example, the communication method of the very small wireless). This signal is output to the antenna. As a result, a radio signal (radio wave) is transmitted from the antenna.

[0064] In the present embodiment, the N2 communication unit 223 detects the electric field strength value of the radio wave received by the antenna. The N2 communication unit 223 outputs a signal indicating the detected electric field strength value to the control unit 221. The control unit 221 stores the data indicating the electric field strength value detected by the N2 communication unit 223 in the storage unit 222. Specifically, the control unit 221 stores the electrolytic strength value of the response signal in the storage unit 222 in association with the identification information (identification information of the detour candidate terminal) acquired from the response signal.

[0065] A wire PL connected to the meter 23 is connected to the connection unit 224. Therefore, the connection unit 224 is wired-connected to the meter 23 via the wire PL. The control unit 221 acquires the measurement result from the meter 23 via the wire PL and the connection unit 224, and stores the data indicating the measurement result in the storage unit 222. The control unit 221 reads out the data indicating the measurement result from the storage unit 222 and creates the center-destined telegram D1 described with reference to FIG. 1.

[0066] The control unit 221 controls each element of the own device (slave unit 22). For example, the control unit 221 controls the storage unit 222 and the N2 communication unit 223. The control unit 221 includes a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The processor controls each element of the own device (slave unit 22) by executing the computer program stored in the storage unit 222. Note that a microcomputer may be configured by the control unit 221 and the storage unit 222.

[0067] The control unit 221 executes the processes described with reference to FIGS. 1 to 4. For example, the control unit 221 executes the connection process, the detour route search process, and the determination process described with reference to FIGS. 1 to 4.

[0068] For example, the control unit 221 determines whether communication with the center device 11 has failed. If it is determined that communication with the center device 11 has failed, the control unit 221 transitions to the transmission restriction mode. In the present embodiment, the control unit 221 counts the number of times it is determined that communication with the center device 11 has failed, and when the count result (number of NG times) reaches a specified number of times, the control unit 221 transitions to the transmission restriction mode. For example, the control unit 221 determines that communication with the center device 11 has failed when communication with the center device 11 via the detour terminal is not successful.

[0069] When the control unit 221 transitions to the transmission restriction mode, it restricts communication with the lower-stage terminal. Specifically, the control unit 221 restricts the transmission of the approval signal. In the present embodiment, when the control unit 221 transitions to the transmission restriction mode, it further restricts the transmission of the response signal. Also, when the control unit 221 transitions to the transmission restriction mode, it restricts self-transmission. That is, the control unit 221 restricts the transmission of the measurement result (data) stored in the storage unit 222 to the center device 11.

[0070] In the present embodiment, when the N2 communication unit 223 receives a signal from the upper-stage terminal, the control unit 221 releases the transmission restriction mode. For example, the control unit 221 may release the transmission restriction mode in response to the N2 communication unit 223 receiving a release signal transmitted from the center device 11 from the upper-stage terminal.

[0071] The storage unit 222 stores various data. For example, the storage unit 222 stores the identification information of the own device (slave device 22), the electrolytic strength value of the response signal, and the measurement result. Further, the storage unit 222 stores the first timeout period, the second timeout period, the edge set information, the identification information of the detour candidate terminal, the non-permission information, and the number of NG times, which were described with reference to FIGS. 1 to 4. The storage unit 222 includes semiconductor memories such as a ROM (Read Only Memory), a RAM (Random Access Memory), and a flash memory, for example.

[0072] The storage unit 222 stores various computer programs executed by the control unit 221 (processor). The various computer programs include computer programs for executing the connection process, the detour route search process, and the determination process, which were described with reference to FIGS. 1 to 4.

[0073] Next, the configuration of the master device 21 will be described with reference to FIGS. 1 to 6. FIG. 6 is a block diagram showing the configuration of the master device 21 of the present embodiment. As shown in FIG. 6, the master device 21 includes a control unit 211, a storage unit 212, an N1 communication unit 213, and an N2 communication unit 214. The control unit 211 is an example of the processing unit of the present invention. The N1 communication unit 213 and the N2 communication unit 214 are examples of the communication unit of the present invention.

[0074] The N1 communication unit 213 is communicably connected to the center device 11. Specifically, the N1 communication unit 213 communicates with the center-side network control device 12 via the wide-area wireless network N1. Therefore, the N1 communication unit 213 is communicably connected to the center device 11 via the wide-area wireless network N1 and the center-side network control device 12. The N1 communication unit 213 is a communication module capable of wide-area communication such as a PHS network, a FOMA network, an LTE network, a 4G network, and a 5G network, for example. The N1 communication unit 213 transmits a center-destined message D1 (measurement result) to the center device 11. Also, the N1 communication unit 213 receives a slave-destined message D2 from the center device 11.

[0075] The N2 communication unit 214 performs wireless communication with the slave unit 22. The N2 communication unit 214 includes, for example, a communication module having an RF-LSI for 920 MHz band communication. The N2 communication unit 214 transmits and receives a connection request signal, an approval signal, a message D1 (measurement result) addressed to the center, and a message D2 addressed to the slave unit with the edge set terminal.

[0076] The control unit 211 controls each element of the own device (master unit 21). For example, the control unit 211 controls the storage unit 212, the N1 communication unit 213, and the N2 communication unit 214. The control unit 211 includes a processor such as a CPU or an MPU, for example. The processor controls each element of the own device (master unit 21) by executing a computer program stored in the storage unit 212. Note that a microcomputer may be configured by the control unit 211 and the storage unit 212.

[0077] The control unit 211 executes the processes described with reference to FIGS. 1 to 4. For example, the control unit 211 executes the determination process described with reference to FIG. 4. Specifically, the control unit 211 determines whether communication with the center device 11 has failed, and if it is determined that communication with the center device 11 has failed, the control unit 211 transitions to the transmission restriction mode. In the present embodiment, the control unit 211 counts the number of times it is determined that communication with the center device 11 has failed, and when the count result (number of NG times) reaches a specified number of times, the control unit 211 transitions to the transmission restriction mode.

[0078] When the control unit 211 transitions to the transmission restriction mode, the control unit 211 restricts communication with the lower terminal. Specifically, the control unit 211 restricts the transmission of the approval signal. In the present embodiment, when the N1 communication unit 213 receives a signal from the center device 11 via the wide area wireless network N1, the control unit 211 releases the transmission restriction mode. For example, the control unit 211 may release the transmission restriction mode in response to the N1 communication unit 213 receiving a release signal transmitted from the center device 11.

[0079] The storage unit 212 stores various data. For example, the storage unit 212 stores the identification information of the own device (parent device 21). Also, the storage unit 212 stores the first timeout period, the second timeout period, the pairing information, and the number of NG times described with reference to FIGS. 1 to 4. The storage unit 212 includes a semiconductor memory such as a ROM, a RAM, and a flash memory, for example.

[0080] The storage unit 212 stores various computer programs executed by the control unit 211 (processor). The various computer programs include a computer program for executing the determination process described with reference to FIG. 4.

[0081] Subsequently, with reference to FIGS. 1 to 5 and FIG. 7, the determination process executed by the control unit 221 of the slave device 22 will be described. FIG. 7 is a flowchart showing the determination process executed by the control unit 221 of the slave device 22 of the present embodiment. As already described, the control unit 221 starts the determination process when self-transmitting. Also, the control unit 221 starts the determination process in response to establishing a communication connection with the lower terminal.

[0082] As shown in FIG. 7, when starting the determination process, the control unit 221 determines whether a communication connection can be established with the upper terminal (step S1). When the control unit 221 determines that a communication connection can be established with the upper terminal (Yes in step S1), the determination process ends.

[0083] When the control unit 221 determines that a communication connection cannot be established with the upper terminal (No in step S1), it determines whether there is a detour route (step S2). Specifically, when the control unit 221 cannot receive a response signal, it determines that there is no detour route. Also, when non-permission information is associated with all the identification information obtained from the response signal, the control unit 221 determines that there is no detour route. On the other hand, when non-permission information is not associated with all or part of the identification information obtained from the response signal, the control unit 221 determines that there is a detour route.

[0084] When the control unit 221 determines that there is no detour route (No in step S2), it executes a counting process to increment the number of NG times by one (step S4).

[0085] When the control unit 221 determines that there is a detour route (Yes in step S2), it determines whether the communication with the center device 11 has been successful (step S3). Specifically, when the control unit 221 can receive the message D2 addressed to the slave unit from the center device 11, it determines that the communication with the center device 11 has been successful. On the other hand, when the control unit 221 cannot receive the message D2 addressed to the slave unit from the center device 11, it determines that the communication with the center device 11 has not been successful.

[0086] When the control unit 221 determines that the communication with the center device 11 has been successful (Yes in step S3), it ends the determination process. When the control unit 221 determines that the communication with the center device 11 has not been successful (No in step S3), it executes a counting process to increment the number of NG times by one (step S4).

[0087] After the counting process, the control unit 221 determines whether the number of NG times has reached the specified number (step S5). When the control unit 221 determines that the number of NG times has not reached the specified number (No in step S5), it ends the determination process. When the control unit 221 determines that the number of NG times has reached the specified number (Yes in step S5), it transitions to the transmission restriction mode (step S6) and ends the determination process.

[0088] In this embodiment, when the control unit 221 determines that there is no detour route, it increments the number of NG times by one. However, when the control unit 221 determines that there is no detour route, it may transition to the transmission restriction mode and end the determination process.

[0089] Next, with reference to FIGS. 1 to 4, 6, and 8, the determination process executed by the control unit 211 of the master unit 21 will be described. FIG. 8 is a flowchart showing the determination process executed by the control unit 211 of the master unit 21 in the present embodiment. As already described, the control unit 211 starts the determination process in response to establishing a communication connection with the lower terminal.

[0090] As shown in FIG. 8, when starting the determination process, the control unit 211 determines whether a communication connection can be established with the communication terminal on the center device 11 side (step S11). If the control unit 211 determines that a communication connection cannot be established with the communication terminal on the center device 11 side (No in step S11), it executes a count process to increase the number of NG times by one (step S13).

[0091] If the control unit 211 determines that a communication connection can be established with the communication terminal on the center device 11 side (Yes in step S11), it determines whether the communication with the center device 11 has been successful (step S12). Specifically, the control unit 211 determines that the communication with the center device 11 has been successful when it can receive the message D2 addressed to the slave unit from the center device 11. On the other hand, the control unit 211 determines that the communication with the center device 11 has not been successful when it cannot receive the message D2 addressed to the slave unit from the center device 11.

[0092] If the control unit 211 determines that the communication with the center device 11 has been successful (Yes in step S12), it ends the determination process. If the control unit 211 determines that the communication with the center device 11 has not been successful (No in step S12), it executes a count process to increase the number of NG times by one (step S13).

[0093] After the count process, the control unit 211 determines whether the number of NG times has reached the specified number (step S14). If the control unit 211 determines that the number of NG times has not reached the specified number (No in step S14), it ends the determination process. If the control unit 211 determines that the number of NG times has reached the specified number (Yes in step S14), it transitions to the transmission restriction mode (step S15) and ends the determination process.

[0094] As described above with reference to FIGS. 1 to 8, according to the present embodiment, when the main unit 21 and the sub-unit 22 fail to communicate with the center device 11, they transition to the outgoing restriction mode. As a result, it is possible to suppress unnecessary communication from being performed.

[0095] For example, in a situation where the sub-unit 22a2 fails to communicate with the center device 11, if the sub-unit 22a2 does not transition to the outgoing restriction mode, the sub-unit 22a3 always executes a connection process with the sub-unit 22a2. As a result, even in a situation where the sub-unit 22a2 fails to communicate with the center device 11, the sub-unit 22a3 transmits the center-destined message D1 to the sub-unit 22a2. However, since the sub-unit 22a2 fails to communicate with the center device 11, the center-destined message D1 is not transmitted to the center device 11. Therefore, the communication between the sub-unit 22a3 and the sub-unit 22a2 becomes unnecessary communication. On the other hand, according to the present embodiment, when the sub-unit 22a2 transitions to the outgoing restriction mode, the sub-unit 22a3 does not communicate with the sub-unit 22a2. Therefore, it is possible to suppress unnecessary communication from being performed between the sub-unit 22a3 and the sub-unit 22a2.

[0096] Also, unnecessary power is consumed by performing unnecessary communication. According to the present embodiment, since it is possible to suppress unnecessary communication from being performed, it is possible to suppress unnecessary power consumption. In particular, the power supplies of the main unit 21 and the sub-units 22 are often batteries. According to the present embodiment, it is possible to suppress battery consumption and extend the operation periods of the main unit 21 and the sub-units 22.

[0097] Furthermore, according to the present embodiment, when the sub-unit 22 transitions to the outgoing restriction mode, the lower-level terminal can transmit the center-destined message D1 using the detour route.

[0098] For example, in a situation where the slave unit 22a2 fails to communicate with the center device 11, if the slave unit 22a2 does not transition to the transmission restriction mode, as already described, the slave unit 22a3 always executes a connection process with the slave unit 22a2. Therefore, the slave unit 22a3 does not form a detour route Rd3 (see FIG. 4). On the other hand, according to the present embodiment, when the slave unit 22a2 transitions to the transmission restriction mode, the slave unit 22a3 forms a detour route Rd3. Therefore, the slave unit 22a3 can transmit the message D1 addressed to the center using the detour route Rd3.

[0099] Also, according to the present embodiment, since the transmission-restricted terminal does not perform self-transmission, it is possible to suppress unnecessary communication. Furthermore, since it is possible to suppress unnecessary communication, it is possible to suppress unnecessary power consumption.

[0100] Also, according to the present embodiment, the transmission-restricted terminal does not transmit a response signal. Therefore, since the transmission-restricted terminal does not become a detour candidate terminal, it is possible to suppress unnecessary communication. Furthermore, since it is possible to suppress unnecessary communication, it is possible to suppress unnecessary power consumption.

[0101] For example, in a situation where the slave unit 22b1 fails to communicate with the center device 11, if the slave unit 22b1 does not transition to the transmission restriction mode, the slave unit 22a2 forms a detour route (detour route Rd2) with the slave unit 22b1 by performing a detour route search process. As a result, even in a situation where the slave unit 22b1 fails to communicate with the center device 11, the slave unit 22a2 transmits the message D1 addressed to the center to the slave unit 22b1. However, since it is a situation where the slave unit 22b1 fails to communicate with the center device 11, the message D1 addressed to the center is not transmitted to the center device 11. Therefore, the communication between the slave unit 22a2 and the slave unit 22b1 becomes unnecessary communication. On the other hand, according to the present embodiment, when the slave unit 22b1 transitions to the transmission restriction mode, the slave unit 22a2 does not communicate with the slave unit 22b1. Therefore, it is possible to suppress unnecessary communication between the slave unit 22a2 and the slave unit 22b1.

[0102] The embodiments of the present invention have been described above with reference to the drawings (Figs. 1 to 8). However, the present invention is not limited to the above embodiments and can be implemented in various forms without departing from the gist thereof. Also, the plurality of components disclosed in the above embodiments can be modified as appropriate. For example, a component among all the components shown in a certain embodiment may be added to the components of another embodiment, or some of the components among all the components shown in a certain embodiment may be deleted from the embodiment.

[0103] The drawings schematically show each component mainly for easy understanding of the invention, and the thickness, length, number, interval, etc. of each illustrated component may be different from the actual ones for convenience in drawing creation. Also, it goes without saying that the configuration of each component shown in the above embodiments is an example and is not particularly limited, and various changes can be made without substantially departing from the effects of the present invention.

[0104] For example, in the embodiment described with reference to Figs. 1 to 8, the meter 23 was not connected to the master unit 21, but the meter 23 may be connected to the master unit 21. In this case, when the master unit 21 transitions to the transmission restriction mode, in addition to suppressing the transmission of the approval signal (Ack signal), it also suppresses its own transmission.

[0105] Also, in the embodiment described with reference to Figs. 1 to 8, the slave unit 22 and the meter 23 were connected by wire via the electric wire PL, but the slave unit 22 and the meter 23 may be wirelessly connected. Similarly, the master unit 21 and the meter 23 may be wirelessly connected.

[0106] Also, in the embodiment described with reference to Figs. 1 to 8, the slave unit 22 transitions to the transmission restriction mode when the number of times of communication failure with the center device 11 reaches a specified number, but the slave unit 22 may transition to the transmission restriction mode in response to a communication failure with the center device 11. Similarly, the master unit 21 may transition to the transmission restriction mode in response to a communication failure with the center device 11.

Industrial Applicability

[0107] The present invention provides a communication terminal and has industrial applicability.

Explanation of Signs

[0108] 11: Center device 21: Master unit 22: Slave unit 22a1 to 22a3: Slave units 22b1 to 22b2: Slave units 22c1 to 22c3: Slave units 211: Control unit 212: Storage unit 213: N1 communication unit 214: N2 communication unit 221: Control unit 222: Storage unit 223: N2 communication unit R: Basic communication route Ra: First basic communication route Rb: Second basic communication route Rc: Third basic communication route Rd1 to Rd3: Detour routes

Claims

1. A communication terminal that communicates with a management device via another communication terminal, comprising: a communication unit that communicates with the other communication terminal; a processing unit that determines whether communication with the management device has failed, and when it is determined that communication with the management device has failed, transitions to a transmission restriction mode that restricts communication with a first communication terminal on the side opposite to the management device side in a predetermined basic communication route; wherein the other communication terminal includes the first communication terminal; the processing unit counts the number of times it is determined that communication with the management device has failed, and when the count result reaches a specified number of times, transitions to the transmission restriction mode; the other communication terminal includes a second communication terminal not included in the basic communication route; the processing unit determines that communication with the management device has failed when communication with the management device via the second communication terminal is not successful.

2. The other communication terminal includes a third communication terminal not included in the basic communication route; when the communication unit receives a connection request signal from the third communication terminal, the processing unit transmits a response signal to the third communication terminal via the communication unit; when the processing unit transitions to the transmission restriction mode, the processing unit restricts the transmission of the response signal. The communication terminal according to claim 1.

3. further comprising a storage unit that stores data; when the processing unit transitions to the transmission restriction mode, the processing unit restricts the transmission of the data to the management device. The communication terminal according to claim 1 or claim 2.

4. The other communication terminal includes a fourth communication terminal on the management device side in the basic communication route; after the processing unit transitions to the transmission restriction mode, when the communication unit receives a signal from the fourth communication terminal, the processing unit releases the transmission restriction mode. The communication terminal according to any one of claims 1 to 3.

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