JP2022166625A - Communication system and wireless communication terminal - Google Patents

Abstract

To provide a communication system and a wireless communication terminal capable of grasping in advance a wireless communication terminal that cannot be detoured.SOLUTION: The communication system 100 includes a plurality of low order wireless communication terminals 22, and a high order wireless communication terminal 21. Each of the plurality of low order wireless communication terminals 22 broadcasts a response requiring signal, receives response information from a bypass destination candidate terminal that is another low order wireless communication terminal 22 within a wireless communication range of its own terminal, and transmits the received response information to the high order wireless communication terminal 21. The high order wireless communication terminal 21 includes a storage unit 212 and a processing unit 211. The storage unit 212 stores the response information received from each of the plurality of low order wireless communication terminals 22. The processing unit 211 identifies the low order wireless communication terminal 22 that cannot execute communication with corresponding detour destination candidate terminals from among the plurality of low order wireless communication terminals 22 on the basis of response information stored in the storage unit 212 and current response information received from each of the plurality of low order wireless communication terminals 22.SELECTED DRAWING: Figure 1

Description

The present invention relates to communication systems and wireless communication terminals.

One type of wireless communication system is a telemetry system (see Patent Document 1, for example). A telemetry system includes a parent device and a plurality of child devices. In the wireless telemetry system of Patent Literature 1, when a child device cannot communicate with a predetermined communication partner, another child device placed within its communication range is a bypass destination terminal ( relay terminal), forms a detour route with the detour destination terminal, and transmits a telegram to the detour destination terminal.

JP 2018-207250 A

However, the child device may not be able to communicate with the detour destination terminal for some reason (for example, an increase in traffic around the child device or a malfunction). In this case, the child device cannot bypass. In the wireless telemetry system of Patent Literature 1, it is not possible to know in advance which wireless communication terminals cannot be detoured when communication cannot be executed with a predetermined communication partner. Therefore, the wireless telemetry system of Patent Document 1 has room for improvement.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and aims to provide a communication system capable of grasping in advance a wireless communication terminal that cannot be bypassed when communication cannot be executed with a predetermined communication partner, and to provide a wireless communication terminal.

A communication system according to the present invention includes a plurality of lower-level wireless communication terminals and a higher-level wireless communication terminal that communicates with the plurality of lower-level wireless communication terminals. Each of the plurality of lower-level wireless communication terminals broadcasts a response request signal, receives response information from a detour destination candidate terminal that is another lower-level wireless communication terminal within the wireless communication range of the lower-level wireless communication terminal, and The response information is transmitted to the upper wireless communication terminal. The response information includes information specific to each of the other lower-layer wireless communication terminals. The upper wireless communication terminal includes a storage section and a processing section. The storage unit stores the response information received from each of the plurality of lower wireless communication terminals. Based on the response information stored in the storage unit and the current response information received from each of the plurality of lower wireless communication terminals, the processing unit selects one of the plurality of lower wireless communication terminals a first lower wireless communication terminal that has failed to receive the response information from each other; Identify the lower wireless communication terminal.

A wireless communication terminal of the present invention communicates with a plurality of lower wireless communication terminals. Each of the plurality of lower-level wireless communication terminals broadcasts a response request signal, receives response information from a detour destination candidate terminal that is another lower-level wireless communication terminal within the wireless communication range of the lower-level wireless communication terminal, and Sending response information to the wireless communication terminal. The response information includes information specific to each of the other lower-layer wireless communication terminals. The wireless communication terminal includes a storage section and a processing section. The storage unit stores the response information received from each of the plurality of lower wireless communication terminals. Based on the response information stored in the storage unit and the current response information received from each of the plurality of lower wireless communication terminals, the processing unit selects one of the plurality of lower wireless communication terminals a first lower wireless communication terminal that has failed to receive the response information from each other; Identify the lower wireless communication terminal.

According to the communication system and the wireless communication terminal of the present invention, it is possible to grasp in advance the wireless communication terminals that cannot be bypassed when communication cannot be executed with a predetermined communication partner.

1 is a diagram showing a communication system according to Embodiment 1 of the present invention; FIG. 3 is a block diagram showing the configuration of a slave device included in the communication system according to Embodiment 1 of the present invention; FIG. 2 is a block diagram showing the configuration of a parent device according to Embodiment 1 of the present invention; FIG. 4 is a flow chart showing processing executed by a control unit of the parent device according to Embodiment 1 of the present invention; 7 is a flow chart showing second determination processing, second notification processing, third determination processing, and third notification processing executed by the control unit of the parent device according to Embodiment 1 of the present invention; FIG. 10 is a sequence diagram showing beacon collection processing executed by the controller of the parent device; FIG. 11 is a sequence diagram showing detour destination candidate search processing executed by the control unit of the first child device; FIG. 11 is a sequence diagram showing a detour destination candidate search process executed by the control unit of the second child device; FIG. 11 is a sequence diagram showing detour destination candidate search processing executed by the control unit of the third child device; FIG. 11 is another sequence diagram showing the detour destination candidate search process executed by the control unit of the second child device; FIG. 12 is another sequence diagram showing the detour destination candidate search processing executed by the control unit of the third child device; FIG. 10 is a diagram showing previous beacon collection results stored in the storage unit of the parent device; FIG. 10 is a diagram showing beacon collection results received by the parent device this time from each of the first to third child devices; FIG. 4 is a sequence diagram showing first determination processing, setting processing, and first notification processing executed by a control unit of a parent device; FIG. 10 is a sequence diagram showing second determination processing and second notification processing executed by the control unit of the parent device; FIG. 11 is a sequence diagram showing third determination processing and third notification processing executed by the controller of the parent device; FIG. 4 is a diagram showing a communication system according to Embodiment 2 of the present invention;

Hereinafter, embodiments of a communication system and a wireless communication terminal according to the present invention will be described with reference to the drawings (FIGS. 1 to 16). It should be noted that descriptions of overlapping descriptions may be omitted as appropriate. Also, in the drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

[Embodiment 1]
Embodiment 1 of the present invention will be described below with reference to FIGS. First, a communication system 100 of this embodiment will be described with reference to FIG. FIG. 1 is a diagram showing a communication system 100 of this embodiment. In this embodiment, communication system 100 is a telemetry system. Hereinafter, the communication system 100 may be referred to as a "telemeter system 100". As shown in FIG. 1 , the telemetry system 100 includes a parent device 21 , a plurality of child devices 22 , and a center device 11 that manages the parent device 21 and the plurality of child devices 22 . The center device 11 is an example of a management device.

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

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 ( 5th generation mobile communication system) network.

In the telemetry system 100, for communication between the parent device 21 and the child device 22 and for communication between the child devices 22, for example, communication using a specified low-power radio (extra-low-power radio) is used. The frequency band for communication by special radio is, for example, the 920 MHz band. In the following, communication by special radio is sometimes referred to as "special radio communication".

A communication partner (wireless communication terminal) of the base unit 21 is predetermined. Similarly, the communication partner (wireless communication terminal) of the handset 22 is predetermined. Therefore, a communication route between the parent device 21 and the child device 22 is predetermined.

Specifically, the parent device 21 and the child device 22 store matching information that defines their own communication partners (wireless communication terminals). Parent device 21 communicates with the communication partner specified by the adoption information. Similarly, the handset 22 communicates with the communication partner specified by the adoption information. Hereinafter, the communication partner (wireless communication terminal) specified by the adoption information may be referred to as "adoption terminal".

In the example shown in FIG. 1, the plurality of child devices 22 includes a first child device 22a to a third child device 22c. The parent device 21 communicates with the first child device 22a to the third child device 22c. Therefore, the interlocking terminals of the parent device 21 include the first child device 22a to the third child device 22c. Each of the first child device 22a to the third child device 22c includes a parent device 21 as an interlaced terminal. In the present embodiment, the parent device 21 is an example of a "higher order wireless communication terminal", and the first handset 22a to the third handset 22c are examples of a "plurality of lower order wireless communication terminals".

Next, the detour destination selection process executed by the child device 22 will be described. When the child device 22 cannot execute communication with the adopted terminal for some reason (for example, an increase in traffic volume around the child device 22 or a failure), the child device 22 executes a detour destination selection process to select a detour destination terminal. Select. Then, communication is performed with the bypass destination terminal. Hereinafter, the child device 22 that executes the detour destination selection process may be referred to as a "detour route formation terminal".

By executing the detour destination selection process, the detour route forming terminal (child device 22) detours one of the wireless communication terminals installed within the communication range (wireless communication range) of itself. Select as the destination terminal. A child device 22 other than the adoption terminal is selected as the detour destination terminal. Hereinafter, among the wireless communication terminals installed within the communication distance range (wireless communication range) of the own device, the child device 22 other than the adopted terminal may be referred to as a "detour destination candidate terminal". The detour destination selection process is a process of selecting one of the detour destination candidate terminals as the detour destination terminal. In addition, the communication distance of the ultra-small wireless communication is 1 m or more and 1000 m or less.

In this embodiment, the detour route forming terminal (child device 22) selects a detour destination terminal by executing beacon collection processing. Specifically, the detour route forming terminal collects beacon information Be from wireless communication terminals set within its wireless communication range by executing beacon collection processing. Hereinafter, a wireless communication terminal set within the wireless communication range of its own device may be referred to as a "terminal within the communication range".

Specifically, the detour route forming terminal broadcasts a beacon request signal ReB. As a result, the detour route forming terminal receives the beacon information Be from the terminal within the communication range. The beacon information Be includes address information, hop count information, and received electric field strength information. The address information indicates the address of the wireless communication terminal. The hop count information indicates the hop count of the wireless communication terminal. The received electric field strength information indicates the received electric field strength.

The address is unique information for each wireless communication terminal. In the following description, unique information may be referred to as "unique information". The number of hops indicates what stage the wireless communication terminal is on from the parent device 21 . Specifically, the base unit 21 is the 0th stage wireless communication terminal. Therefore, the hop count of parent device 21 is "0". The first handset 22a to the third handset 22c are wireless communication terminals in the first stage. Therefore, the number of hops of the first handset 22a to the third handset 22c is "1".

The received electric field strength indicates the electric field strength value of the radio waves (radio waves carrying the beacon request signal ReB) received by the terminal within the communication range from the detour route forming terminal. The electric field strength value is, for example, an RSSI (Received Signal Strength Indicator) value.

The detour route forming terminal selects a detour destination terminal based on the collected beacon information Be. For example, the detour route forming terminal selects the detour destination candidate terminal having the highest received electric field strength from among the detour destination candidate terminals having the same hop count as the own device or a smaller hop count than the own device. It may be selected as a terminal.

In the example shown in FIG. 1, the wireless communication range of the parent device 21 includes the first child device 22a to the third child device 22c. The wireless communication range of the first child device 22a includes the master device 21 and the second child device 22b. The radio communication range of the second child device 22b includes the parent device 21, the first child device 22a, and the third child device 22c. The wireless communication range of the third child device 22c includes the master device 21 and the second child device 22b. Therefore, the detour destination candidate terminal for the first extension device 22a is the second extension device 22b. The detour destination candidate terminals for the second handset 22b are the first handset 22a and the third handset 22c. A detour destination candidate terminal for the third handset 22c is the second handset 22b.

For example, when the received electric field strength of the first handset 22a is greater than the received electric field strength of the third handset 22c as a result of collecting the beacon information Be, the second handset 22b selects the first handset 22a as the detour destination terminal. Select.

Next, a detour destination candidate search process executed by the adoption terminal (child device 22) of the parent device 21 will be described. The adopted terminal of parent device 21 searches for a detour destination candidate terminal by executing a detour destination candidate search process, and transmits detour destination candidate information to parent device 21 . The detour destination candidate information includes information unique to each of the detour destination candidate terminals (unique information). Note that the detour destination candidate search process is repeatedly executed at a predetermined cycle. The predetermined cycle is, for example, a 45-day cycle. Hereinafter, the predetermined cycle may be referred to as "first cycle".

In this embodiment, the adopted terminal (child device 22) of the parent device 21 executes the beacon collection process each time the first period elapses. That is, every time the first period elapses, the beacon request signal ReB is broadcast and the beacon information Be is received (collected) from the terminals within the communication range. Then, the collected beacon information Be is transmitted to the parent device 21 as detour destination candidate information. Hereinafter, the collected beacon information Be may be referred to as "beacon collection result C". The beacon request signal ReB is an example of a "response request signal", and the address information (unique information) included in the beacon information Be is an example of "response information".

Specifically, the first child device 22a transmits the beacon collection result C to the parent device 21 based on the beacon information Be received from each of the parent device 21 and the second child device 22b. Similarly, the second handset 22b transmits the beacon collection result C to the base 21 based on the beacon information Be received from each of the base 21, the first handset 22a and the third handset 22c. The third child device 22c transmits the beacon collection result C to the parent device 21 based on the beacon information Be received from each of the parent device 21 and the second child device 22b.

Note that the beacon collection result C includes the beacon information Be of the child device 22 that has the same number of hops as the child device 22 that transmits the beacon collection result C or has a smaller number of hops. However, the beacon collection result C may further include the beacon information Be of the child device 22 having a larger number of hops than the child device 22 transmitting the beacon collection result C.

Next, the isolated terminal specifying process executed by the parent device 21 will be described. The isolated terminal identification process is a process of searching for a child device 22 that cannot execute communication with a detour destination candidate terminal from among the adopted terminals of the parent device 21 . Hereinafter, the child device 22 that cannot communicate with the bypass destination candidate terminal may be referred to as an "isolated terminal". An isolated terminal cannot execute communication with a bypass destination terminal. Therefore, when the isolated terminal cannot execute communication with the master device 21, it cannot transmit a telegram addressed to the center device 11. FIG. An isolated terminal is an example of a “second lower wireless communication terminal”.

In the example shown in FIG. 1, the first handset 22a becomes an isolated terminal when communication with the second handset 22b cannot be executed for some reason. The second handset 22b becomes an isolated terminal when it cannot communicate with either the first handset 22a or the third handset 22c for some reason. When the third handset 22c cannot communicate with the second handset 22b for some reason, it becomes an isolated terminal.

As already explained, the parent device 21 receives the detour destination candidate information from its own adoption terminal. The parent device 21 stores the detour destination candidate information. Then, the stored past candidate detour destination information is compared with the received current candidate detour destination information, and an isolated terminal is specified based on the comparison result. Specifically, the master device 21 identifies the slave devices 22 that have failed to receive the beacon information Be (response information) from among its own adopted terminals, and selects the isolated terminal from among the identified slave devices 22. , the child device 22 that cannot communicate with the corresponding detour destination candidate terminal is specified.

For example, since the detour destination candidate terminal for the third handset 22c is only the second handset 22b, when the beacon information Be cannot be mutually received between the second handset 22b and the third handset 22c, The parent device 21 identifies the third child device 22c as an isolated terminal.

In the present embodiment, after identifying the isolated terminal, the master device 21 executes the first determination process of determining the state of wireless communication with the isolated terminal. Then, when the wireless communication state does not match a predetermined condition, the first notification process is executed. The first notification process is a process of transmitting the first notification information Nt1 to the center device 11. FIG. The first notification information Nt1 indicates that the child device 22 identified as the isolated terminal cannot communicate with the corresponding detour destination candidate terminal.

For example, the master device 21 may determine the radio wave condition with respect to the isolated terminal by the first determination process. Specifically, the base unit 21 may determine whether or not the electric field intensity of the radio waves received by the isolated terminal from the base unit 21 is equal to or less than a predetermined threshold. When the electric field intensity of the radio wave received by the isolated terminal from the base unit 21 is equal to or less than a predetermined threshold value, the radio wave condition between the base unit 21 and the isolated terminal is unstable. may not be able to communicate with When the electric field strength of the radio wave received by the isolated terminal from the base unit 21 is equal to or less than a predetermined threshold value, the base unit 21 transmits the first notification information Nt1 addressed to the center unit 11 to the center side network control unit 12. . As a result, the center device 11 receives the first notification information Nt1.

Note that the first determination process does not have to be executed. In this case, when identifying the isolated terminal, the master device 21 transmits the first notification information Nt1 to the center device 11 .

Next, the configuration of the handset 22 will be described with reference to FIGS. 1 and 2. FIG. FIG. 2 is a block diagram showing the configuration of the handset 22 included in the communication system 100 of this embodiment. As shown in FIG. 2 , the child device 22 includes a control section 221 , a storage section 222 , a communication section 223 and a connection section 224 .

The communication unit 223 performs wireless communication with other wireless communication terminals. For example, as described with reference to FIG. 1, the communication unit 223 establishes a communication connection with the adoption terminal and the detour destination terminal, and transmits and receives messages to and from the adoption terminal and the detour destination terminal. Also, as described with reference to FIG. 1, the communication unit 223 broadcasts the beacon request signal ReB and receives beacon information Be from terminals within the communication range. Furthermore, the communication unit 223 transmits the beacon collection result C to the parent device 21 as detour destination candidate information, as described with reference to FIG. The communication unit 223 includes, for example, a communication module having an RF-LSI for 920 MHz band communication.

Specifically, the communication unit 223 has an antenna (not shown). The communication unit 223 transmits and receives radio signals (radio waves) through an antenna. The communication unit 223 converts (decodes) the received radio signal into a signal that can be processed by the control unit 221 and outputs the signal to the control unit 221 . In addition, the communication unit 223 converts the signal output from the control unit 221 to the communication unit 223 into a signal conforming to a predetermined wireless communication system (for example, a communication system of extra-small wireless). This signal is output to the antenna. As a result, a radio signal (radio wave) is transmitted from the antenna.

In this embodiment, the communication unit 223 measures the electric field intensity value (received electric field intensity) of radio waves received by the antenna. The communication unit 223 outputs a signal indicating the measured electric field strength value to the control unit 221 .

An electric wire PL connected to the meter 23 is connected to the connection portion 224 . Therefore, the connecting portion 224 is wire-connected to the meter 23 via the electric wire PL. The meter 23 is installed for each consumer such as a private residence, company, and various facilities. The meter 23 is a measuring instrument. The measurement target of the meter 23 is, for example, the usage of resources such as gas, water, or electricity. The meter 23 measures the usage of resources such as gas, water, or electricity, and outputs the measurement result to the wire PL.

The control unit 221 acquires the measurement result from the meter 23 via the electric wire PL and the connection unit 224 and causes the storage unit 222 to store data indicating the measurement result. The control unit 221 reads the data indicating the measurement result from the storage unit 222 and creates a telegram addressed to the center indicating the measurement result. The center-addressed message is transmitted to the center device 11 . For example, the first handset 22a transmits a telegram addressed to the center to the base 21 via the communication unit 223 of its own handset 22a. As a result, the base unit 21 transmits the center-addressed message to the center device 11 via the wide area wireless network Ne and the center side network control device 12 .

The control unit 221 controls each element of its own device (child device 22). For example, the control section 221 controls the storage section 222 and the communication section 223 . The control unit 221 includes a processor such as a CPU (Central Processing Unit) or MPU (Micro Processing Unit). The processor controls each element of its own device (child device 22 ) by executing a computer program stored in the storage unit 222 . A microcomputer may be configured by the control unit 221 and the storage unit 222 .

The control unit 221 executes various processes. For example, the control unit 221 executes the detour destination selection process and the detour destination candidate search process described with reference to FIG. More specifically, the control unit 221 executes beacon collection processing.

The storage unit 222 stores various data. For example, the storage unit 222 stores self-adoption information, self-address information, self-hop number information, beacon information Be, and measurement results. The storage unit 222 also stores information indicating the first cycle described with reference to FIG. The storage unit 222 includes, for example, semiconductor memory such as ROM (Read Only Memory), RAM (Random Access Memory), and flash memory.

The storage unit 222 stores various computer programs executed by the control unit 221 (processor). Various computer programs include, for example, a computer program for executing the detour destination selection process and the detour destination candidate search process described with reference to FIG. In this embodiment, the computer program for executing the detour destination selection process and the detour destination candidate search process includes the computer program for executing the beacon collection process described with reference to FIG.

Next, the configuration of the parent device 21 will be described with reference to FIGS. 1 and 3. FIG. FIG. 3 is a block diagram showing the configuration of the parent device 21 of this embodiment. As shown in FIG. 3 , master device 21 includes control unit 211 , storage unit 212 , first communication unit 213 , and second communication unit 214 . The control unit 211 is an example of a processing unit. The first communication unit 213 and the second communication unit 214 are examples of a transmission unit.

The first communication unit 213 is communicably connected to the center device 11 . Specifically, the first communication unit 213 communicates with the center-side network control device 12 via the wide area wireless network Ne. Therefore, the first communication unit 213 is communicably connected to the center device 11 via the wide area wireless network Ne and the center side network control device 12 . The first communication unit 213 is, for example, a communication module capable of wide area communication such as a PHS network, FOMA network, LTE network, 4G network, and 5G network. The first communication unit 213 transmits the measurement results to the center device 11 . Also, the first communication unit 213 transmits the first notification information Nt1 to the center device 11 as described with reference to FIG.

The second communication unit 214 performs wireless communication with the adoption terminal. The second communication unit 214 includes, for example, a communication module having an RF-LSI for 920 MHz band communication. The second communication unit 214 establishes a communication connection with the adoption terminal and transmits/receives messages to/from the adoption terminal. For example, the second communication unit 214 receives measurement results from the adoption terminal. The second communication unit 214 also broadcasts a beacon request signal ReB and receives beacon information Be from terminals within the communication range. Furthermore, as described with reference to FIG. 1, the second communication unit 214 receives the beacon collection result C from the adopted terminal as detour destination candidate information.

The control unit 211 controls each element of its own device (master device 21). For example, the control section 211 controls the storage section 212 , the first communication section 213 and the second communication section 214 . The control unit 211 includes a processor such as a CPU or MPU, for example. The processor controls each element of its own device (master device 21 ) by executing a computer program stored in storage unit 212 . A microcomputer may be configured by the control unit 211 and the storage unit 212 .

The control unit 211 executes various processes. For example, the control unit 211 executes beacon collection processing. Further, the control unit 211 executes the isolated terminal specifying process and the first determination process described with reference to FIG. Furthermore, the control unit 221 executes the first notification process and transmits the first notification information Nt1 to the center device 11 as described with reference to FIG.

The storage unit 212 stores various data. For example, the storage unit 212 stores self-adoption information, self-address information, and self-hop count information. Further, the storage unit 212 stores the beacon collection result C (detour destination candidate information) described with reference to FIG. The storage unit 212 includes semiconductor memory such as ROM, RAM, and flash memory.

The storage unit 212 stores various computer programs executed by the control unit 211 (processor). For example, various computer programs include computer programs for performing beacon collection processes. Various computer programs include computer programs for executing the isolated terminal identification process and the first determination process described with reference to FIG. Further, various computer programs include computer programs for performing first notification processing.

Next, processing executed by the control unit 211 of the parent device 21 of the present embodiment will be described with reference to FIGS. 1 to 4. FIG. FIG. 4 is a flowchart showing processing executed by the control unit 211 of the master device 21 of this embodiment. The processing shown in FIG. 4 starts when the master device 21 receives the beacon collection result C from the adoption terminal.

Upon receiving the beacon collection result C transmitted from the adopted terminal via the second communication unit 214, the control unit 211 executes the isolated terminal identification process described with reference to FIG. In this embodiment, the control unit 211 first determines whether or not the previous beacon collection result C stored in the storage unit 212 matches the beacon collection result C received this time (step S1). Note that the previous beacon collection result C is the beacon collection result C obtained when the adopted terminals of the master device 21 do not include the isolated terminal.

When the control unit 211 determines that the previous beacon collection result C and the current beacon collection result C match (Yes in step S1), the processing shown in FIG. 4 ends. If the control unit 211 determines that the previous beacon collection result C and the current beacon collection result C do not match (No in step S1), it identifies an isolated terminal (step S2).

Specifically, the control unit 211 compares the beacon collection result C of the previous time with the beacon collection result C of this time, identifies the child devices 22 that could not receive the beacon information Be from each other, and identifies the child devices 22 that have not received the beacon information Be. Among them, the child device 22 that cannot execute communication with the corresponding detour destination candidate terminal is specified as an isolated terminal. Hereinafter, the slave unit 22 that cannot receive the beacon information Be from each other may be referred to as a "monitoring target terminal".

Note that if the previous beacon collection result C and the current beacon collection result C do not match, the control unit 211 does not store the current beacon collection result C in the storage unit 212 . Therefore, the storage unit 212 retains the previous beacon collection result C (the beacon collection result C acquired when no isolated terminal is included in the adopted terminals of the parent device 21).

After identifying the isolated terminal, the control unit 211 executes the first determination process described with reference to FIG. Specifically, the control unit 211 transmits a radio wave measurement request signal ReM to the isolated terminal. The radio wave measurement request signal ReM is a signal requesting the received electric field strength information M. FIG. Upon receiving the radio measurement request signal ReM, the communication unit 223 of the isolated terminal (child device 22) measures the electric field strength value of the radio wave carrying the radio measurement request signal ReM. The control unit 221 of the isolated terminal (child device 22) transmits received electric field strength information M indicating the measured electric field strength value to the master device 21 via the communication unit 223 based on the radio wave measurement request signal ReM. When the control unit 211 of the base device 21 acquires the received electric field strength information M via the second communication unit 214, it determines whether or not the electric field strength value is equal to or less than the threshold (step S3).

When the control unit 211 determines that the electric field strength value is not equal to or less than the threshold value (No in step S3), it ends the processing shown in FIG. When the control unit 211 determines that the electric field strength value is equal to or less than the threshold value (Yes in step S3), the control unit 211 executes the first notification process described with reference to FIGS. The notification information Nt1 is transmitted (step S4). As a result, it is possible to notify the administrator of the center device 11 that the telemetry system 100 includes an isolated terminal and that the radio wave environment of the isolated terminal is unstable.

In this embodiment, the control unit 211 executes the setting process after transmitting the first notification information Nt1 (step S5). The setting process is a process of changing the period in which the monitored terminal executes the detour destination candidate search process to a second period shorter than the first period. For example, if the first cycle is a 45 day cycle, the second cycle may be a 7 day cycle. After executing the setting process, the control unit 221 ends the process shown in FIG.

Specifically, the control unit 211 transmits the setting signal Set to the monitored terminal via the second communication unit 214 . The setting signal Set indicates an instruction to change the first period to the second period, and the execution count N, which is the number of times the detour destination candidate search process is executed in the second period. The execution count N is, for example, four or five.

When receiving the setting signal Set via the communication unit 223, the control unit 221 of the monitoring target terminal (child device 22) changes the cycle of the detour destination candidate search process from the first cycle to the second cycle based on the setting signal Set. change. Specifically, the second period is stored in the storage unit 222 . Further, the control unit 221 of the monitoring target terminal (child device 22) stores the execution count N in the storage unit 222 based on the setting signal Set. As a result, the monitored terminal executes the detour destination candidate search process N times in the second period.

Note that the setting process may be executed after the first notification process is executed.

Next, with reference to FIGS. 1 to 3 and 5, second determination processing, second notification processing, third determination processing, and third notification processing executed by control unit 211 of parent device 21 of the present embodiment explain. FIG. 5 is a flow chart showing the second determination process, the second notification process, the third determination process, and the third notification process executed by the control unit 211 of the master device 21 of this embodiment. The process shown in FIG. 5 starts when the master device 21 receives the beacon collection result C from the terminal to be monitored.

When the control unit 211 receives the beacon collection result C transmitted from the monitored terminal via the second communication unit 214, the control unit 211 determines whether the isolated terminal can communicate with the bypass destination candidate terminal. judge. Specifically, the control unit 211 determines whether or not the beacon collection result C of the monitored terminal held in the storage unit 212 matches the current beacon collection result C obtained from the monitored terminal. (Step S11).

As described with reference to FIG. 4, the beacon collection result C held in the storage unit 212 is the beacon collection result C obtained when the adopted terminal of the base unit 21 does not include an isolated terminal. be.

When the control unit 211 determines that the beacon collection result C of the monitored terminal held in the storage unit 212 matches the current beacon collection result C obtained from the monitored terminal (Yes in step S11), 2 Judgment processing is executed.

Specifically, the control unit 211 determines that the number of times the beacon collection result C of the monitored terminal held in the storage unit 212 and the current beacon collection result C obtained from the monitored terminal match consecutively is N2. It is determined whether or not the number of times has reached (step S12). Here, N2 is an integer equal to or greater than 2 and is stored in the storage unit 212 in advance. N2 times may indicate the same value as the number N of executions, or may indicate a value different from the number N of executions.

When it is determined that the beacon collection result C of the monitored terminal held in the storage unit 212 and the current beacon collection result C acquired from the monitored terminal have not consecutively matched N2 times ( No in step S12), the control unit 211 terminates the process shown in FIG.

When it is determined that the number of consecutive matches between the beacon collection result C of the monitored terminal held in the storage unit 212 and the current beacon collection result C obtained from the monitored terminal has reached N2 times ( Yes in step S12), the control unit 211 executes the second notification process (step S13), and ends the process shown in FIG.

The second notification process is a process of transmitting the second notification information Nt2 to the center device 11. FIG. The second notification information Nt2 indicates that the isolated terminal can now communicate with the bypass destination candidate terminal. In other words, the second notification information Nt2 indicates that the isolated terminal has recovered from the isolated state.

On the other hand, when the control unit 211 determines that the beacon collection result C of the monitored terminal held in the storage unit 212 does not match the current beacon collection result C obtained from the monitored terminal (No in step S11). ), the third determination process is executed.

Specifically, the control unit 211 determines that the number of times the beacon collection result C of the monitored terminal held in the storage unit 212 does not match the current beacon collection result C acquired from the monitored terminal reaches N3 times. It is determined whether or not (step S14). Here, N3 is an integer equal to or greater than 2, and is stored in advance in storage unit 212 . N3 times may indicate the same value as the number N of executions, or may indicate a value different from the number N of executions. Also, N3 times may indicate the same value as N1 times, or may indicate a different value from N1 times.

When it is determined that the number of discrepancies between the beacon collection result C of the monitored terminal held in the storage unit 212 and the current beacon collection result C obtained from the monitored terminal has not reached N3 times (step S14 No), the control unit 211 terminates the processing shown in FIG.

When it is determined that the number of discrepancies between the beacon collection result C of the monitored terminal held in the storage unit 212 and the current beacon collection result C obtained from the monitored terminal has reached N3 times (Yes in step S14). ), the control unit 211 executes the third notification process (step S15), and ends the process shown in FIG.

The third notification process is a process of transmitting the third notification information Nt3 to the center device 11. FIG. The third notification information Nt3 indicates, for example, that the isolated terminal is out of order. In other words, the control unit 211 may transmit the failure notification to the center device 11 .

Note that after the monitored terminal executes the detour destination candidate search process N times in the second cycle, the parent device 21 sends a setting signal to the monitored terminal to return the cycle of the detour destination candidate search process from the second cycle to the first cycle. Send to

Next, an example of operations of the parent device 21 and the first child device 22a to the third child device 22c will be described with reference to FIGS. 1 to 15. FIG. First, an example of the operation of the parent device 21 and the first child device 22a to the third child device 22c will be described with reference to FIGS. 6 to 9. FIG.

FIG. 6 is a sequence diagram showing beacon collection processing executed by control unit 211 of master device 21 . As shown in FIG. 6 , the control unit 211 of the base device 21 broadcasts the beacon request signal ReB via the second communication unit 214 . As a result, the control unit 211 of the parent device 21 receives the beacon information Be from each of the first child device 22a to the third child device 22c via the second communication unit 214. FIG. The control unit 211 of the master device 21 causes the storage unit 212 to store the beacon collection result C of the master device 21 .

The beacon collection result C of the parent device 21 indicates that the parent device 21 can communicate with the first child device 22a to the third child device 22c. Specifically, the beacon collection result C of the parent device 21 includes unique information (address information) of each of the first child device 22a to the third child device 22c.

FIG. 7 is a sequence diagram showing detour destination candidate search processing executed by the control unit 221 of the first child device 22a. As shown in FIG. 7, the control unit 221 of the first handset 22a broadcasts the beacon request signal ReB via the communication unit 223. As shown in FIG. As a result, the control unit 221 of the first child device 22a receives the beacon information Be from each of the parent device 21 and the second child device 22b via the communication unit 223. FIG.

Upon receiving the beacon information Be, the control unit 221 of the first child device 22a transmits the beacon collection result C to the parent device 21 . The control unit 211 of the parent device 21 causes the storage unit 212 to store the beacon collection result C of the first child device 22a.

The beacon collection result C of the first child device 22a indicates that the first child device 22a can communicate with the parent device 21 and the second child device 22b. Specifically, the beacon collection result C of the first child device 22a includes unique information (address information) of each of the parent device 21 and the second child device 22b.

FIG. 8 is a sequence diagram showing detour destination candidate search processing executed by the control unit 221 of the second child device 22b. As shown in FIG. 8, the control unit 221 of the second handset 22b broadcasts the beacon request signal ReB via the communication unit 223. FIG. As a result, the control unit 221 of the second child device 22b receives the beacon information Be from each of the parent device 21, the first child device 22a, and the third child device 22c via the communication unit 223.

Upon receiving the beacon information Be, the control unit 221 of the second child device 22b transmits the beacon collection result C to the parent device 21 . The control unit 211 of the parent device 21 causes the storage unit 212 to store the beacon collection result C of the second child device 22b.

The beacon collection result C of the second handset 22b indicates that the second handset 22b can communicate with the base 21, the first handset 22a, and the third handset 22c. Specifically, the beacon collection result C of the second child device 22b includes unique information (address information) of each of the parent device 21, the first child device 22a, and the third child device 22c.

FIG. 9 is a sequence diagram showing detour destination candidate search processing executed by the control unit 221 of the third child device 22c. As shown in FIG. 9, the control unit 221 of the third handset 22c broadcasts the beacon request signal ReB via the communication unit 223. FIG. As a result, the control unit 221 of the third child device 22c receives the beacon information Be from each of the parent device 21 and the second child device 22b via the communication unit 223. FIG.

Upon receiving the beacon information Be, the control unit 221 of the third child device 22c transmits the beacon collection result C to the parent device 21 . The control unit 211 of the parent device 21 causes the storage unit 212 to store the beacon collection result C of the third child device 22c.

The beacon collection result C of the third child device 22c indicates that the third child device 22c can communicate with the parent device 21 and the second child device 22b. Specifically, the beacon collection result C of the third child device 22c includes unique information (address information) of each of the parent device 21 and the second child device 22b.

Next, referring to FIGS. 10 and 11, when communication cannot be executed between the second child device 22b and the third child device 22c for some reason, the parent device 21, the second child device 22b and the The operation of the third handset 22c will be described.

FIG. 10 is another sequence diagram showing the detour destination candidate search processing executed by the control unit 221 of the second child device 22b. As shown in FIG. 10, the control unit 221 of the second handset 22b broadcasts the beacon request signal ReB via the communication unit 223. As shown in FIG. When communication cannot be executed between the second handset 22b and the third handset 22c for some reason, the communication unit 223 of the second handset 22b does not receive the beacon information Be from the third handset 22c. Therefore, the control unit 221 of the second child device 22b receives the beacon information Be from each of the parent device 21 and the first child device 22a via the communication unit 223. FIG.

Upon receiving the beacon information Be, the control unit 221 of the second child device 22b transmits the beacon collection result C to the parent device 21 . The control unit 211 of the parent device 21 causes the storage unit 212 to store the beacon collection result C of the second child device 22b.

When communication cannot be executed between the second handset 22b and the third handset 22c for some reason, the beacon collection result C of the second handset 22b indicates that the second handset 22b has 22a. Specifically, the beacon collection result C of the second child device 22b includes unique information (address information) of each of the parent device 21 and the first child device 22a.

FIG. 11 is another sequence diagram showing the detour destination candidate search process executed by the control unit 221 of the third child device 22c. As shown in FIG. 11, the control unit 221 of the third handset 22c broadcasts the beacon request signal ReB via the communication unit 223. FIG. When communication cannot be executed between the second handset 22b and the third handset 22c for some reason, the communication unit 223 of the third handset 22c does not receive the beacon information Be from the second handset 22b. Therefore, the control unit 221 of the third child device 22 c receives the beacon information Be from the parent device 21 via the communication unit 223 .

Upon receiving the beacon information Be, the control unit 221 of the third child device 22c transmits the beacon collection result C to the parent device 21 . The control unit 211 of the parent device 21 causes the storage unit 212 to store the beacon collection result C of the third child device 22c.

If communication cannot be executed between the second handset 22b and the third handset 22c for some reason, the beacon collection result C of the third handset 22c will Show what you can do. Specifically, the beacon collection result C of the third child device 22 c includes unique information (address information) of the parent device 21 .

Next, isolated terminal identification processing executed by the control unit 211 of the master device 21 will be described with reference to FIGS. 12A and 12B. 12A is a diagram showing the previous beacon collection result C stored in the storage unit 212 of the master device 21. FIG. FIG. 12B is a diagram showing the beacon collection results C received by the parent device 21 this time from each of the first child device 22a to the third child device 22c. Specifically, FIG. 12A shows the beacon collection result C obtained by the parent device 21 when the adopted terminals of the parent device 21 do not include the isolated terminal. FIG. 12B shows the beacon collection result C obtained by the parent device 21 when communication cannot be executed between the second mobile device 22b and the third mobile device 22c for some reason.

As shown in FIGS. 12A and 12B, when communication cannot be executed between the second handset 22b and the third handset 22c for some reason, the third handset 22c is obtained from the beacon collection result C of the second handset 22b. is lost, and the unique information of the second handset 22b is lost from the beacon collection result C of the third handset 22c. Therefore, the control unit 221 of the master device 21 compares the beacon collection result C of the previous time stored in the storage unit 212 with the beacon collection result C received this time, so that the beacon information Be (response information) can be exchanged with each other. The second handset 22b and the third handset 22c are specified as the handset 22 that could not receive the signal.

As shown in FIG. 12B, the second handset 22b is not an isolated terminal because it can communicate with the first handset 22a. On the other hand, the third handset 22c cannot communicate with other handsets 22 that have the same hop count or a smaller hop count than the third handset 22c. Therefore, the control unit 211 of the base device 21 identifies the third handset 22c as the isolated terminal based on the beacon collection result C received this time.

Next, referring to FIG. 13, the first determination processing, setting processing, and first notification processing executed by the control unit 211 of the parent device 21 will be described. FIG. 13 is a sequence diagram showing first determination processing, setting processing, and first notification processing executed by control unit 211 of master device 21 .

As shown in FIG. 13, when the control unit 211 of the base unit 21 identifies the third handset 22c as an isolated terminal, it transmits a radio wave measurement request signal ReM to the third handset 22c. As a result, the control unit 211 of the parent device 21 receives the received electric field strength information M from the third child device 22c via the second communication unit 214. FIG.

Upon receiving the received electric field strength information M, the control unit 211 of the master device 21 determines whether or not the electric field strength value is equal to or less than the threshold. When the controller 211 of the master device 21 determines that the electric field strength value is equal to or less than the threshold value, it transmits the setting signal Set to the second slave device 22b and the third slave device 22c, which are terminals to be monitored. As a result, the cycle in which the second handset 22b and the third handset 22c execute the detour destination candidate search process is changed from the first cycle to the second cycle. Also, the number of times the second handset 22b and the third handset 22c execute the detour destination candidate search process in the second cycle is set to N times.

In the example shown in FIG. 13 , the control unit 211 of the master device 21 executes the first notification process after executing the setting process, and transmits the first notification information Nt1 to the center device 11 .

Next, with reference to FIG. 14, the second determination process and second notification process executed by the control unit 211 of the parent device 21 will be described. FIG. 14 is a sequence diagram showing second determination processing and second notification processing executed by control unit 211 of master device 21 .

In the example shown in FIG. 14, N2 times is two times. As shown in FIG. 14, the control unit 211 of the master device 21 collects the beacon collection results C ( 12A) and the current beacon collection result C acquired from the monitored terminal reach twice (N2 times), the second notification process is executed, and the second notification information Nt2 is sent to the center device 11.

Next, with reference to FIG. 15, the third determination process and the third notification process executed by the controller 211 of the parent device 21 will be described. FIG. 15 is a sequence diagram showing the third determination process and the third notification process executed by control unit 211 of master device 21 .

In the example shown in FIG. 15, N3 times is N times. As shown in FIG. 15, the control unit 211 of the master device 21 collects the beacon collection results C ( 12A) and the current beacon collection result C acquired from the monitored terminal reach N times (N3 times), the third notification process is executed, and the third notification information Nt3 is sent to the center. Send to device 11 .

Embodiment 1 of the present invention has been described above with reference to FIGS. According to this embodiment, it is possible to grasp in advance the child device 22 (isolated terminal) that cannot be detoured when communication with the adopted terminal becomes impossible for some reason.

Further, according to the present embodiment, by the first determination process, it is possible to grasp in advance an isolated terminal that is more likely to be unable to communicate with the adopted terminal.

Further, according to the present embodiment, it is possible to temporarily shorten the cycle of the detour destination candidate search process by the monitored terminal by the setting process. Therefore, it is possible to confirm earlier whether deterioration of the radio wave environment is temporary or not.

Note that in the present embodiment, in the first determination process, the base device 21 determines the radio wave condition between the base device 21 and the isolated terminal based on the received electric field intensity of the isolated terminal. The radio wave condition between the parent device 21 and the isolated terminal may be determined based on the electric field strength of the radio wave received from the parent device 21 .

Further, in the present embodiment, the parent device 21 executes the setting process once, but the parent device 21 executes the setting process a plurality of times, and the cycle of the detour destination candidate search process is changed stepwise from the second cycle. may be close to the first period. For example, the master device 21 may set a third cycle shorter than the first cycle and longer than the second cycle after the monitored terminal executes the detour destination candidate search process N times in the second cycle. For example, if the first cycle is a 45-day cycle and the second cycle is a 7-day cycle, the third cycle may be a 15-day cycle.

Moreover, in the present embodiment, the master device 21 executes the second determination process and the third determination process, but both or one of the second determination process and the third determination process may be omitted.

In addition, in the present embodiment, the master device 21 has the beacon collection result C of the monitored terminal held in the storage unit 212 of the master device 21 and the current beacon collection result C acquired from the monitored terminal. When the number of matching times reached N2 times, the second notification process was executed. It may be determined whether or not the slave device 22 other than the wireless communication terminal included in the collection result C is included. In this case, the master device 21 includes the slave device 22 other than the wireless communication terminal included in the beacon collection result C of the isolated terminal held in the storage unit 212 in the current beacon collection result C acquired from the isolated terminal. When the number of times it is determined that there is N2 times, the second notification process is executed. For example, when the third handset 22c is an isolated terminal, the handset 22 different from the handset 21 and the second handset 22b is included in the beacon collection result C acquired from the third handset 22c. Determine whether or not Here, the child device 22 different from the parent device 21 and the second child device 22b is, for example, the child device 22 newly installed within the wireless communication range of the third child device 22c.

In addition, in the present embodiment, the master device 21 does not match the beacon collection result C of the monitored terminal held in the storage unit 212 of the master device 21 with the current beacon collection result C obtained from the monitored terminal. When the number of times reaches N3, the third notification process is executed. The third notification process may be executed when the number of times it is determined that the child device 22 other than the wireless communication terminal included in the list is not included reaches N3 times.

[Embodiment 2]
Next, Embodiment 2 of the present invention will be described with reference to FIG. However, matters different from those of the first embodiment will be explained, and explanations of matters that are the same as those of the first embodiment will be omitted. Embodiment 2 differs from Embodiment 1 in that the slave device 22 executes the isolated terminal identification process.

FIG. 16 is a diagram showing the communication system 100 of this embodiment. As shown in FIG. 16 , a communication system 100 (telemeter system) includes a parent device 21 , a plurality of child devices 22 and a center device 11 .

In the example shown in FIG. 16, the plurality of child devices 22 includes a first child device 22d, a second child device 22d1, a third child device 22d2, and a fourth child device 22d3. The parent device 21 communicates with the first child device 22d. Therefore, the framed terminals of the parent device 21 include the first child device 22d. Each of the second child device 22d1 to the fourth child device 22d3 includes a first child device 22d. In the present embodiment, the first handset 22d is an example of a "higher order wireless communication terminal", and the second handset 22d1 to the fourth handset 22d3 are examples of a "plurality of lower order wireless communication terminals".

Each of the second handset 22d1 to the fourth handset 22d3 executes a detour destination candidate search process and transmits detour destination candidate information to the first handset 22d. In this embodiment, the detour destination candidate information is the beacon collection result C. FIG.

The first handset 22d executes an isolated terminal specifying process. Therefore, based on the beacon collection result C (detour destination candidate information) received from each of the second handset 22d1 to the fourth handset 22d3, the first handset 22d receives the second handset 22d1 to the fourth handset 22d3. Identify an isolated terminal from among

After identifying the isolated terminal, the first handset 22d executes the first determination process. Then, when the wireless communication state between the first handset 22d and the isolated terminal does not meet the predetermined condition, the first notification process is executed to send the first notification information Nt1 addressed to the center device 11 to the parent device. machine 21. As a result, the center device 11 receives the first notification information Nt1.

The first child device 22d further executes setting processing, and changes the cycle in which the monitored terminal executes the detour destination candidate search processing to a second cycle shorter than the first cycle. After that, the first child device 22d determines whether or not the isolated terminal can now communicate with the detour destination candidate terminal.

When the isolated terminal becomes able to execute communication with the detour destination candidate terminal, the first child device 22d executes the second notification process and transmits the second notification information Nt2 addressed to the center device 11 to the parent device. 21. On the other hand, if the isolated terminal has not become able to execute communication with the detour destination candidate terminal, the first handset 22d executes the third notification process and sends the third notification information Nt3 addressed to the center device 11. to the base unit 21.

The second embodiment of the present invention has been described above with reference to FIG. According to this embodiment, it is possible to grasp in advance the child device 22 (isolated terminal) that cannot be detoured when communication with the adopted terminal becomes impossible for some reason.

The embodiments of the present invention have been described above with reference to the drawings (FIGS. 1 to 16). However, the present invention is not limited to the above-described embodiments, and can be embodied in various aspects without departing from the spirit of the present invention. Also, the plurality of constituent elements disclosed in the above embodiments can be modified as appropriate. For example, some of all the components shown in one embodiment may be added to the components of another embodiment, or some configurations of all the components shown in one embodiment may be added. Elements may be deleted from the embodiment.

In order to facilitate understanding of the invention, the drawings schematically show each component mainly, and the thickness, length, number, interval, etc. It may be different from the actual from the top. Further, the configuration of each component shown in the above embodiment is an example and is not particularly limited, and it goes without saying that various modifications are possible within a range that does not substantially deviate from the effects of the present invention. .

For example, in the embodiments described with reference to FIGS. 1 to 16, meter 23 was not connected to master device 21, but meter 23 may be connected to master device 21. FIG.

In addition, in the embodiment described with reference to FIGS. 1 to 16, slave unit 22 and meter 23 are connected by wire PL, but slave unit 22 and meter 23 may be wirelessly connected. Similarly, master device 21 and meter 23 may be wirelessly connected.

INDUSTRIAL APPLICABILITY The present invention provides a communication system and a wireless communication terminal, and has industrial applicability.

11: Center device 21: Parent device 22: Child device 100: Communication system (telemeter system)
211: Control unit 212: Storage unit Be: Beacon information C: Beacon collection result M: Received field strength information N: Number of executions Nt1: First notification information Nt2: Second notification information Nt3: Third notification information ReB: Beacon request signal ReM: Radio wave measurement request signal Set: Setting signal

Claims (8)

A communication system comprising a plurality of lower-level wireless communication terminals and a higher-level wireless communication terminal that communicates with the plurality of lower-level wireless communication terminals,
Each of the plurality of lower-level wireless communication terminals broadcasts a response request signal, receives response information from a detour destination candidate terminal that is another lower-level wireless communication terminal within the wireless communication range of the lower-level wireless communication terminal, and transmitting response information to the upper wireless communication terminal, the response information including information specific to each of the other lower wireless communication terminals;
The upper wireless communication terminal,
a storage unit that stores the response information received from each of the plurality of lower wireless communication terminals;
Based on the response information stored in the storage unit and the current response information received from each of the plurality of lower wireless communication terminals, the plurality of lower wireless communication terminals send the response information to each other. from among the identified first lower wireless communication terminals that cannot communicate with the corresponding bypass destination candidate terminals. A communication system comprising: an identifying processing unit; further comprising a management device that manages the upper wireless communication terminal and the plurality of lower wireless communication terminals;
2. The upper wireless communication terminal further comprises a transmitting unit configured to transmit information indicating that communication with the detour destination candidate terminal corresponding to the second lower wireless communication terminal is not possible to the management device. a communication system as described in . The processing unit causes the second lower wireless communication terminal to respond based on the response information stored in the storage unit and the current response information received from each of the first lower wireless communication terminals. determined whether or not communication could be executed with the corresponding detour destination candidate terminal, and if the second-lower wireless communication terminal was able to execute communication with the corresponding detour destination candidate terminal, the 3. The communication system according to claim 2, wherein information indicating that communication can be executed between said second-lower wireless communication terminal and said corresponding detour destination candidate terminal is transmitted to said management device via a transmission unit. The processing unit determines a wireless communication state with the second lower wireless communication terminal, and, if the wireless communication state does not match a predetermined condition, transmits the second lower wireless communication terminal through the transmitting unit. 4. The communication system according to claim 2, wherein the radio communication terminal transmits information indicating that communication with the corresponding detour destination candidate terminal is not possible to the management device. each of the plurality of low-order wireless communication terminals transmits the response request signal at a predetermined first period;
When the wireless communication state does not meet the condition, the processing unit transmits a signal for setting a cycle of transmitting the response request signal to a second cycle shorter than the first cycle. 5. The communication system according to claim 4, transmitting to the first lower wireless communication terminal. 6. The communication system according to claim 5, wherein said first lower-order wireless communication terminal transmits said response request signal a predetermined number of times in said second cycle. The processing unit transmits the response request signal via the transmission unit after the first lower wireless communication terminal transmits the response request signal the predetermined number of times in the second cycle. 7. The communication system according to claim 6, wherein a signal is transmitted to said first lower-order radio communication terminal to set the to a third period longer than said second period and shorter than said first period. A wireless communication terminal that communicates with a plurality of lower wireless communication terminals,
Each of the plurality of lower-level wireless communication terminals broadcasts a response request signal, receives response information from a detour destination candidate terminal that is another lower-level wireless communication terminal within the wireless communication range of the lower-level wireless communication terminal, and transmitting response information to the wireless communication terminal, the response information including information specific to each of the other lower wireless communication terminals;
The wireless communication terminal is
a storage unit that stores the response information received from each of the plurality of lower wireless communication terminals;
Based on the response information stored in the storage unit and the current response information received from each of the plurality of lower wireless communication terminals, the plurality of lower wireless communication terminals send the response information to each other. from among the identified first lower wireless communication terminals that cannot communicate with the corresponding bypass destination candidate terminals. A wireless communication terminal comprising: an identifying processing unit;

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