JP2019193200A - Wireless communication system - Google Patents

Abstract

To make it possible to convey a telegram sent by a slave unit that has exceeded the number of steps to a master unit in a wireless communication system composed of a master unit and a plurality of slave units wirelessly connected to the master unit at a plurality of levels of layers with limited number of levels.SOLUTION: If it is determined that the number of steps has been exceeded (step ST1: Yes) on the basis of report route information to an own terminal in a received message, a slave unit stores the report route to the own terminal and the report terminal in a step number over information table (step ST2) and resets a report terminal and the report route from the own terminal (step ST4).SELECTED DRAWING: Figure 4

Description

  The present invention relates to a wireless communication system.

  Monitor information (gas meter and water meter meter readings) acquired by the slave unit, including a master unit and a wireless communication system comprising a multi-stage slave unit that is wirelessly connected to the master unit and a center unit There is a remote monitoring system that reports a value, a gas leak alarm, a remaining battery charge alarm, etc.) to a center device via a parent machine (Patent Document 1).

  In this remote monitoring system, communication between the center unit and the master unit is performed via a wireless or wired commercial communication line, and the “master unit, first stage slave unit, second stage slave unit,... Wireless communication in a wireless communication system configured by “child devices” (N is an integer of 3 or more) is performed using specific low-power wireless or the like. The number of slave units is limited to a certain number (for example, four) at the stage of system design of the remote monitoring system.

  Sensors such as gas meters, water meters, gas leak detectors, etc. are connected to each slave unit. The monitoring information generated by these sensors is acquired, and the telegram containing the monitoring information is sent to the first-stage slave unit. Report directly to the master unit, the second-stage slave unit, ..., the N-th slave unit via the upper (upper) slave unit, that is, the higher-level slave unit as a relay slave unit, Perform relay communication.

  When constructing such a wireless communication system, it is a common practice to construct a network area of a wireless communication terminal over a wide area by sequentially installing slave units around the base unit after installation.

  When a slave unit is installed, a terminal search message (route search message) is broadcasted to surrounding terminals, and a response from the surrounding terminals (parent unit, slave unit) can be received to connect to the surrounding terminals. It is a mechanism to know what. At this time, in order to ensure a good communication state, a method of preferentially selecting from terminals responding with a predetermined received electric field strength of a certain level or higher is generally known.

  That is, when installing the slave unit, the slave unit broadcasts a terminal search message with the terminal ID (terminal identification information) of its own terminal added thereto, and a terminal response message (route) that is a response from surrounding terminals within a predetermined time. Check whether there is a response message. When there is a response, from the terminal ID, the received electric field strength (the received electric field strength of the terminal search message) and the number of stages included in the terminal response message, the terminal directly above the terminal with the received electric field strength equal to or greater than a certain threshold The terminal ID and the number of steps are registered in the storage unit of the terminal as report route information.

  In addition, if the received electric field strength decreases due to changes in the surrounding communication environment after installation, the communication route becomes unstable by newly searching for nearby terminals and re-registering the directly above terminals. Are also used.

JP 2010-87761 A

  However, in the conventional remote monitoring system described above, the number of slave units may fluctuate due to route reconstruction. Therefore, when the number of relay slave units decreases, the subordinate slave units, that is, the slave units are relayed. The number of slave units that have been used as slave units also decreases, and as a result of exceeding the limit number of steps, relaying may not be possible.

  A case where the number of limiting stages is four will be described with reference to FIGS. Here, FIG. 16 is a diagram showing a notification route before route reconstruction, and FIG. 17 is a diagram showing a notification route after route reconstruction. In the following description, a slave unit that acquires monitoring information and transmits a notification message including the monitoring information is referred to as a notification terminal.

  As shown in FIG. 16, when the fourth-stage slave unit h is a reporting terminal, the fourth-stage slave unit h → the third-stage slave unit g → the second-stage slave unit e → the first-stage slave unit b → the communication route of the master unit To the center device.

  On the other hand, as shown in FIG. 17, a communication abnormality occurs between the slave unit b and the master unit, and after the slave unit b reconfigures the route, it is directly below the first-stage slave unit a, that is, 2 When changing to the stage, the slave unit e, the slave unit g, and the slave unit h change to the third, fourth, and fifth stages, respectively. In this case, when the slave unit h reports to the center unit, the communication route is limited to the slave unit a because the slave unit h → the slave unit g → the slave unit e → the slave unit b → the slave unit a → the master unit. An excess of the number of steps (hereinafter referred to as an over-number of steps) is detected, relaying to the master unit is stopped, and reporting to the center device becomes impossible.

  The present invention has been made in order to solve such a problem, and the object of the present invention is to provide a master unit and a plurality of slave units wirelessly connected in a multi-stage hierarchy with the number of stages limited to the master unit. In the wireless communication system, it is possible to transmit a notification message transmitted from the slave unit that has exceeded the number of stages to the master unit.

  The present invention is a wireless communication system including a parent device and a plurality of child devices wirelessly connected in a plurality of layers whose number of steps is limited to the parent device, wherein the child device is connected to a center device from a subordinate terminal The message message receiving means for receiving the message message to the message, the stage number over detecting means for detecting overstage number based on the report route information to the own terminal in the message message received by the message message receiving means, and the number of stages The over-stage number information storage means for storing the over-stage number information consisting of the report route information and the terminal ID of the reporting terminal in the notification message when the over-number detection means detects over-stage number, and the notification It is a wireless communication system having route information processing means for rewriting report route information in a message only to report route information of its own terminal.

  According to the present invention, in a wireless communication system comprising a base unit and a plurality of slave units that are wirelessly connected in a multi-stage hierarchy with the number of stages limited to the base unit, a notification message transmitted from the slave unit that has exceeded the number of stages. Can be transmitted to the main unit.

It is a figure which shows the structure of the remote monitoring system which concerns on embodiment of this invention. It is a figure which shows the data frame of a message | telegram. It is a block diagram which shows schematic structure of a subunit | mobile_unit. It is a flowchart which shows the 1st example of a report message relay operation. It is a sequence diagram which shows the communication procedure of the report message | telegram when the step number over has not generate | occur | produced. It is a figure which shows schematic structure of the report message | telegram transmitted by the sequence shown by FIG. It is a sequence diagram which shows the communication procedure of the report message | telegram when the step number over has generate | occur | produced. It is a figure which shows schematic structure of the report message | telegram transmitted by the sequence shown by FIG. 7, and the overstage number information registered. It is a flowchart which shows the example of request | requirement message relay operation | movement. It is a sequence diagram which shows the communication procedure of the request | requirement message | telegram to the terminal in which the number of steps has exceeded. FIG. 11 is a diagram illustrating a schematic configuration of a request message transmitted in the sequence illustrated in FIG. 10 and referenced stage number over-information. It is a flowchart which shows the 2nd example of report message relay operation | movement. It is a figure which shows the 1st example of the request | requirement message relay operation | movement by the terminal holding the step number over information notified by broadcast transmission. It is a figure which shows the 2nd example of the request | requirement message | telegram relay operation | movement by the terminal holding the stage number over information notified by broadcast transmission. It is a figure which shows the 3rd example of the request | requirement message relay operation | movement by the terminal holding the step number over information notified by broadcast transmission. It is a figure which shows the report route before route reconstruction. It is a figure which shows the report route after route reconstruction.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<Configuration of remote monitoring system>
FIG. 1 is a diagram showing a configuration of a remote monitoring system according to an embodiment of the present invention.

  This remote monitoring system is used, for example, for automatic meter reading of a gas meter or a water meter, and is wirelessly connected to the center device 1, the master unit 2, and the master unit 2 in a plurality of stages with a limited number of stages. And a wireless communication system according to an embodiment of the present invention including a plurality of slave units 3. In this remote monitoring system, the number of slave units in the wireless communication system is limited to four.

  Communication between the parent device 2 and the center device 1 is performed via a commercial communication line such as a mobile phone line, and wireless communication in a wireless communication system including the parent device 2 and the first to fourth child devices 3 is performed. Is performed using a specific low power radio. In the following description, a terminal is used when the parent device and the child device are not distinguished.

  Sensors such as gas meters, water meters, and gas leak detectors are connected to each slave unit, and monitoring information generated by these sensors is acquired and relayed through the superior slave unit, that is, the superior slave unit. As a slave unit, multistage relay communication is notified to the master unit 2.

  In FIG. 1, the number of slave units in the wireless communication system is four, but there are three-stage configurations and five-stage or more configurations. In FIG. 1, each slave unit has a single directly-on terminal. However, there is a configuration having multiple directly-on terminals.

<Data frame of telegram>
FIG. 2 is a diagram showing a data frame of a telegram in the remote monitoring system according to the embodiment of the present invention. Here, FIG. 2A shows a data frame of a notification message that the slave unit reports to the center device, and FIG. 2B shows a data frame of a request message that the center device requests information from the slave unit.

  As shown in FIG. 2A, the data frame 100 of the report message includes report route information, that is, the storage areas 101 to 104 of the terminal ID of the terminal that becomes the report route, the storage area 105 of the terminal ID of the report terminal, It comprises command and argument storage areas 106 and 107 serving as report data.

  Each terminal stores its terminal ID in the terminal ID storage areas 101 to 104 in order when transmitting a notification message to the terminal directly above. That is, when the fourth-stage slave unit becomes a notification terminal and reports to the center apparatus 1, the fourth-stage slave unit stores the terminal ID of the third-stage slave unit in the terminal ID storage area 104, and the third-stage slave unit The terminal ID of the second stage slave unit is stored in the terminal ID storage area 103, the second stage slave unit stores the terminal ID of the first stage slave unit in the terminal ID storage area 102, and the first stage slave unit is the terminal ID. The terminal ID of the parent device is stored in the storage area 101.

  Further, as shown in FIG. 2B, the request message data frame 200 includes request route information, that is, storage areas 201 to 204 of terminal IDs of terminals that serve as request routes (communication routes of request messages), and request terminals. Terminal ID storage area 205 and command and argument storage areas 206 and 207 serving as request data.

  When the center device 1 transmits request data to the fourth-stage child device, the terminal device stores the request ID information in the terminal ID storage areas 201, 202, 203, and 204, respectively. The terminal ID of the third stage slave unit is stored. Each terminal, when receiving the request message, transmits (relays) the request message to the terminal immediately below based on the request route information.

<Schematic configuration of slave unit>
FIG. 3 is a block diagram showing a schematic configuration of the slave unit in the remote monitoring system shown in FIG.

  As illustrated, the slave unit 3 includes a control unit 31, a storage unit 32, a wireless transmission / reception unit 33, an external I / F (interface) unit 34, a display unit 35, and an operation input each connected to the control unit 31. A portion 36 is provided. An antenna 37 is connected to the wireless transmission / reception unit 33.

  The control unit 31 includes, for example, a microprocessor and its peripheral circuits, and performs control of the entire slave unit 3, arithmetic processing, and the like. In addition, the control unit 31 is a means realized by processing the program and data stored in the storage unit 32. As a means realized by processing the program and data, the step number over detection means 311, the step number over information storage means 312, the route information processing means 313, and Table reference means 314 is provided. Details of these means will be described later.

  Further, the control unit 31 processes the program and data stored in the storage unit 32 and controls the wireless transmission / reception unit 33 to thereby send a notification message transmission unit, a notification message reception unit, a step number over information transmission unit, a step number over limit. Realize information receiving means.

  The storage unit 32 includes a nonvolatile memory such as a ROM (including a rewritable memory) and a volatile memory such as a RAM. The ROM stores a control program necessary for operating the slave unit 3, various setting data, and the like. The RAM stores information necessary for each program being executed by the control unit 31 (terminal ID, wireless channel, communication electric field strength, number of stages of the terminal itself). Here, the stage number over information table 321 is illustrated (details will be described later).

  The wireless transmission / reception unit 33 performs wireless communication with other child devices 3 and the parent device 2 by a specific low power wireless or the like. External devices such as a gas meter and a water meter are connected to the external I / F unit 34. The display unit 35 is configured by an LED or the like, and is a user I / F that displays an operation state of the child device 3 and the like. The operation input unit 36 includes a button, a switch, and the like, and is a user I / F for inputting predetermined settings for the child device 3.

<Transmission of notification message from slave unit to center unit>
FIG. 4 is a flowchart showing a first example of the report message relay operation. FIG. 5 is a sequence diagram showing a communication procedure of a notification message when the number of stages has not exceeded. FIG. 6 shows a schematic configuration of a notification message transmitted in the sequence shown in FIG. FIG. FIG. 7 is a sequence diagram showing a communication procedure of a notification message when the number of steps is over. FIG. 8 is a notification message transmitted in the sequence shown in FIG. 7 and the number of registered steps. It is a figure which shows schematic structure of over information. Hereinafter, with reference to these drawings, an operation of reporting from the fourth-stage slave unit 3 to the center device 1 will be described.

《Relay operation of notification message》
First, a first example of the message telegram relay operation will be described with reference to FIGS.

  When receiving the notification message, the slave unit 3 analyzes the notification route information in the notification message and determines whether or not the number of steps has been exceeded (step ST1, step number detection means 311). This determination is made based on, for example, whether or not there is a vacancy (unstored part) in the terminal ID storage area (101 to 104) of the report route information in the data frame 100 of the received report message.

  When it is determined that the number of steps has not been exceeded (step ST1: No), that is, when the number of steps has not been detected, a report route to the terminal immediately above is added in the report message (step ST3, route information processing means) 313). Specifically, the terminal ID of the terminal directly above is stored in the terminal ID storage area (101 to 104) of the data frame 100. And it transmits to a terminal immediately above (step ST5), and a message | telegram message | telegram relay operation | movement is complete | finished.

  When it is determined that the number of steps has been exceeded (step ST1: Yes), that is, when the number of steps has been detected, the report route to the terminal itself and the report terminal (the report terminal and the report route information in the report message) Terminal IDs other than terminals) are stored in the over-stage information table (step ST2, over-stage information storage means 312).

  Next, the reporting route is reset from the reporting terminal and the terminal itself (step ST4). That is, the terminal ID other than the terminal ID of the own terminal in the data frame 100 in the notification message is deleted, the terminal ID of the own terminal is stored in the terminal ID storage area 104, and the terminal ID of the terminal directly above is stored in the terminal ID storage area 103. Store. And it transmits to a terminal immediately above (step ST5), and a message | telegram message | telegram relay operation | movement is complete | finished.

<Communication procedure of notification message when the number of steps is not over>
Next, with reference to FIG. 5 and FIG. 6, the communication procedure of the notification message and the content of the notification message when the number of stages has not exceeded will be described.

  As shown in FIG. 5, the terminals immediately above each of the slave unit E, the slave unit D, the slave unit C, and the slave unit B are the slave unit D, the slave unit C, the slave unit B, and the master unit. The number of stages of the machine B, the slave machine C, the slave machine D, and the slave machine E is the first stage, the second stage, the third stage, and the fourth stage. Since the number of stages has not been exceeded, the slave unit D, the slave unit C, and the slave unit B perform the operation in the case of “ST1: No” in FIG. 4 in this sequence.

  In response to the occurrence of the notification event, the slave unit E transmits a notification message to the slave unit D that is the terminal directly above (sequence S1). As shown in FIG. 6A, this report message has a report event as report data, a terminal ID of its own terminal as a report terminal, and a terminal ID of a terminal directly above (slave unit D) as a report route. .

  Slave device D transmits (relays) a notification message to slave device C, which is a terminal directly above (sequence S2). As shown in FIG. 6B, this notification message is obtained by adding the terminal ID of the terminal directly above (the child device C) to the notification route information in the notification message from the child device E.

  The subunit | mobile_unit C transmits (relays) a report message to the subunit | mobile_unit B which is a terminal immediately above (sequence S3). As shown in FIG. 6C, this notification message is obtained by adding the terminal ID of the terminal directly above (the child device B) to the notification route information in the notification message from the child device D.

  Slave device B transmits (relays) a notification message to the master device (sequence S4). As shown in FIG. 6D, this report message is obtained by adding the terminal ID of the terminal directly above (master unit) to the report route information in the report message from the slave unit C. Communication from the base unit to the center unit was omitted.

《Communication procedure of notification message when the number of steps is over》
Next, with reference to FIG.7 and FIG.8, the communication procedure of the report message | telegram when the number of steps over has occurred and the content of the report message will be described.

  As shown in FIG. 7, each terminal directly above the slave unit E, the slave unit D, the slave unit C, the slave unit B, and the slave unit A includes the slave unit D, the slave unit C, the slave unit B, and the slave unit. A, the master unit, the number of stages of each of the slave units A, B, C, D, E is 1st stage, 2nd stage, 3rd stage, 4th stage, 5th stage Eyes. This report route is a report route shown in FIG. 5, in which a communication abnormality occurs between the slave unit B and the master unit, and after the slave unit B reconstructs the route, it is directly below the first-stage slave unit A, that is, 2 This is the notification route when the stage changes.

  Since the terminals immediately above each of the slave unit E, the slave unit D, and the slave unit C are the same as those in FIG. 5, the messages in the sequences S11 to S13 in FIG. 7 are as shown in FIGS. This is the same as the notification message (FIGS. 6A to 6C) in sequences S1 to S3. However, since the terminal directly above the slave unit B has changed from the master unit to the slave unit A, the notification message in the sequence S14 is stored in the first notification route information (stored in the terminal ID storage area 101 as shown in FIG. 8D). Terminal ID) becomes the handset A.

  Next, handset A detects the number of steps over based on the report route information in the report message received from handset B, that is, based on the absence of space in terminal ID storage area (101-104), The step number over information is stored in the step number over information table 321 and the report route is reset (FIG. 4: steps ST1 → ST2 → ST4).

  FIG. 8E shows the over-stage information 321a stored in the over-stage information table 321. The over-stage information includes the terminal ID of the slave E as a reporting terminal and reporting route information to the terminal itself. Moreover, the report message including the reset report route is shown in FIG. 8F. In the reset report route, the terminal ID other than the terminal ID of the own terminal in the data frame 100 in the report message is deleted, the terminal ID of the own terminal is stored in the terminal ID storage area 104, and the terminal ID of the parent device is It is stored in the terminal ID storage area 101.

  The subunit | mobile_unit A transmits the report message | telegram containing the reset report route information to the main | base station which is an immediately above terminal (sequence S15). Communication from the base unit to the center unit was omitted.

<Transmission of request message from center unit to slave unit>
FIG. 9 is a flowchart illustrating an example of a request message relay operation. FIG. 10 is a sequence diagram showing a communication procedure of a request message to a terminal in which the number of stages has been exceeded. FIG. 11 is a request message transmitted in the sequence shown in FIG. It is a figure which shows schematic structure of stage number over information.

<< Relay operation of request message >>
First, an operation for relaying a request message from a terminal directly above will be described with reference to FIGS.

  When receiving the request message, handset 3 retrieves the terminal ID of the requesting terminal from data frame 200 and searches over-stage information table 321, and the terminal ID of the requesting terminal is the report destination (the terminal ID of the reporting terminal) in the table. ) (Step ST11 → ST12, table reference means 314).

  As a result of the determination, if they do not match (step ST12: No), a request message is transmitted (relayed) to the terminal immediately below according to the request route from the center apparatus 1, that is, the request route information in the data frame 200 (step ST14), and the request The telegram relay operation is terminated.

  As a result of the determination, if they match (step ST12: Yes), the reporting route corresponding to the requesting terminal is applied from the over-stage information table 321 and the request route starting from the own terminal, that is, the terminal ID of the own terminal is set as the terminal ID. The request route stored in the storage area 201 and stored in the terminal ID storage area in the subsequent terminal ID storage area is reset. Next, the request message is transmitted (relayed) to the terminal directly below (step ST13), and the request message relay operation is terminated.

<< Communication procedure of request message to terminal with overstage >>
With reference to FIG. 10 and FIG. 11, the content of the communication procedure of the request message to the terminal where the number of stages has exceeded will be described.

  As shown in FIG. 10, the direct terminals of the parent device, the child device A, the child device B, the child device C, and the child device D are the child device A, the child device B, the child device C, and the child device D. , Slave unit E, and slave unit A, slave unit B, slave unit C, slave unit D, and slave unit E have 1st stage, 2nd stage, 3rd stage, 4th stage, 5th stage, respectively. It is. That is, in the same state as FIG. 7, the slave unit E is over the number of stages, and the over-stage information table 321 of the slave unit A holds the over-stage information stored in the slave unit A in FIG. .

  The center device transmits a request message to the parent device in response to the occurrence of the request event (sequence S21). The base unit receives the request message, and transmits (relays) the request message to handset A, which is a direct terminal, according to the request route information in the request message (sequence S22). As shown in FIG. 11A, the request message includes a request event as request data, a terminal ID of a slave E as a request terminal, a terminal ID of a master as the head of the request route, and a request route. Terminal ID of handset A as the second. This request route is a return of the report route.

  The subunit | mobile_unit A receives a request | requirement message | telegram, takes out terminal ID of a request | requirement terminal, and searches the step number over information table 321 (FIG. 9: step ST11). FIG. 11B shows the over-stage information 321a held in the over-stage information table 321.

  Slave unit A determines that the number-of-stages over information is stored using the terminal ID of slave unit E, which is the terminal ID of the requesting terminal, as the reporting terminal (FIG. 9: step ST12: Yes). The request route is reset, and the request message is transmitted to the child device B (sequence S23, FIG. 9: step ST13). The request message transmitted at this time is shown in FIG. 11C.

  Slave unit B receives the request message and transmits (relays) it to slave unit C according to the request route information (sequence S24, FIG. 9: step ST14). Thereafter, the slave unit C and the slave unit D transmit request messages to the slave unit D and the slave unit E, respectively, according to the request route (sequences S25 and S26, FIG. 9: step ST14). The contents of the request message transmitted in sequences S24 to S26 are the same as the request message (FIG. 11C) transmitted in sequence S23. The request route information is used for the loopback communication of the slave unit E.

<Broadcast transmission of over-stage information>
In the embodiment described above, only the terminal that has detected the number of stages is stored with the number of stages information, so that if the terminal is replaced or removed, a request message is sent from the center device to the terminal that has exceeded the number of stages. I can't do that. Therefore, this problem is solved by executing the procedure shown in FIG.

  FIG. 12 is a flowchart showing a second example of the report message relay operation. In this figure, steps ST21, ST22, ST23, ST25, ST26 are the same as steps ST1, ST2, ST3, ST4, ST5 in the first example of the message telegram relay operation (FIG. 4), respectively.

  In other words, this second example is a step added to the first example in step ST24 in which a notification route to the terminal and the notification terminal, that is, a step of notifying the surrounding terminals by broadcast transmission of the over-stage information is broadcast. It is. The surrounding terminals receive this over-stage information and store it in the respective over-stage information table 321. Also, the peripheral terminals may notify the center apparatus 1 that the number of steps over information has been stored.

  In addition, for relaying a notification message from a subordinate terminal, even if a terminal that detected an over-stage is replaced or removed, another terminal executes the operation shown in FIG. 4 to detect an over-stage. No problem.

<Request message relay operation of the terminal holding the over-stage information notified by broadcast transmission>
Next, the request message relay operation by the terminal holding the over-stage information notified by broadcast transmission, that is, the over-stage information notified in step ST24 in FIG. 12 will be described with reference to three examples (FIGS. 13 to 15). . Note that the wireless connection relationship (directly above terminal, directly below terminal) of the slave units in the following examples is different from that in FIGS. 7 and 10. Further, in the following figure, the terminals holding the number of steps over information are hatched.

First example
FIG. 13 is a diagram illustrating a first example of a request message relay operation by a terminal that holds the number-of-stages over information notified by broadcast transmission.

Here, as the premise of the state shown in the figure, the following operations (i) to (ii) have been executed.
(i) Slave unit D detects the number of steps of subordinate terminals, and broadcasts the number of steps over information to the surrounding terminals (report terminal: slave unit H, report route information: slave unit E-slave unit F-slave unit G). Send.
(ii) The slave unit A, the slave unit B, and the slave unit C receive the stage number over information and store it in the stage number over information table 321.

  The base unit receives the request message sent from the center device to handset H, and transmits (relays) to handset B according to the request route information (sequence S31). Slave unit B retrieves the terminal ID of the requesting terminal, searches the over-stage information table 321, and if they match, resets the requested route information based on the report route information held in the over-stage information table 321. The request message is transmitted (relayed) to the slave E (sequence S32). Thereafter, the slave unit E, the slave unit F, and the slave unit G transmit (relay) request messages to the slave unit F, the slave unit G, and the slave unit H, respectively, according to the request route information. The request route information is used for the loopback communication of the slave unit E.

<< Second Example >>
FIG. 14 is a diagram illustrating a second example of the request message relay operation by the terminal holding the over-stage information notified by broadcast transmission.

The resetting of the request route information can be executed not only by the slave unit directly under the master unit but also by the slave unit under the slave unit. In this example, the slave unit B at the third stage executes. Here, as the premise of the state shown in the figure, the following operations (iii) to (iv) have been executed.
(iii) Slave unit I detects that the number of steps of subordinate terminals has been exceeded, and broadcasts the number of steps to the surrounding terminals (report terminal: slave unit H, report route information: slave unit E-slave unit F-slave unit G). Send.
(iv) The slave unit B, the slave unit C, and the slave unit D receive the stage number over information and store it in the stage number over information table 321.

  The parent device receives the request message sent from the center device to the child device H, and transmits (relays) it to the child device J according to the request route information (sequence S41). The slave unit J transmits (relays) the request message to the slave unit K according to the request route information (sequence S42), and the slave unit K transmits (relays) the request message to the slave unit B according to the request route information (sequence S43). ). Slave unit B retrieves the terminal ID of the requesting terminal, searches the over-stage information table 321, and if they match, resets the requested route information based on the report route information held in the over-stage information table 321. The request message is transmitted (relayed) to the slave E (sequence S44). Thereafter, the slave unit E, the slave unit F, and the slave unit G transmit (relay) request messages to the slave unit F, the slave unit G, and the slave unit H, respectively, according to the request route information. The request route information is used for the loopback communication of the slave unit H.

<Third example>
FIG. 15 is a diagram illustrating a third example of the request message relay operation by the terminal holding the over-stage information notified by broadcast transmission.

  In this example, the slave unit D and the slave unit T detect that the number of stages is over, and store the over-stage information in the stage number over information table 321 of the terminal itself. In addition, the slave unit D broadcasts and transmits the over-stage information to surrounding terminals, and the slave devices A, B, and C receive it and store them in the over-stage information table 321 of its own terminal.

  The parent device receives the request message sent from the center device to the child device H, and transmits (relays) the request message to the child device T according to the request route information (sequence S51). The slave unit T retrieves the terminal ID of the requesting terminal, searches the over-stage information table 321, and if they match, resets the requested route information based on the report route information held in the over-stage information table 321. The request message is transmitted (relayed) to the slave unit J (sequence S52). Slave device J transmits (relays) the request message to slave device K according to the request route information (sequence S53), and slave device K transmits the request message to slave device B according to the request route information in the request message (relay). (Sequence S54). Slave unit B retrieves the terminal ID of the requesting terminal, searches the over-stage information table 321, and if they match, resets the requested route information based on the report route information held in the over-stage information table 321. The request message is transmitted (relayed) to the slave E (sequence S55). Thereafter, the slave unit E, the slave unit F, and the slave unit G transmit (relay) request messages to the slave unit F, the slave unit G, and the slave unit H, respectively, according to the request route information. The request route information is used for the loopback communication of the slave unit H.

  Thus, the detection of the number of stages is not one place on the report route. If the upper terminal detects the number of steps over and stores it in the number of steps over information table 321 of its own terminal, it is possible to connect further, so theoretically infinite connection is possible.

As described above, according to the wireless communication system according to the embodiment of the present invention, the following effects (1) to (3) can be obtained.
(1) A terminal that has detected an overage in the process where the reporting terminal relays via a higher-level terminal stores the reporting route information that has reached the terminal, and the reporting route information in the reporting message that has reached the terminal. By omitting the reporting route information other than the reporting terminal and its own terminal, it becomes possible to make a relay request to a higher-level terminal.
(2) For returning a request message from the center device 1, the route information to the reporting terminal is searched from the reporting route information stored in the terminal that has received the relay request for the reporting message. Then, the corresponding route information in the table is reflected in the request route information in the request message, and the return communication to the reporting terminal in which the number of stages is over becomes possible.
(3) A terminal that has detected an excessive number of stages broadcasts the number of stages to the surrounding terminals and stores it in the surrounding terminals, so that even if the terminal that has detected the excessive number of stages is replaced, the center A request message can be delivered from the device 1 to a terminal whose number of stages is over.

  2 ... Master unit, 3 ... Slave unit, 33 ... Wireless transmission / reception unit, 311 ... Over-stage detection means, 312 ... Over-stage information storage means, 313 ... Route information processing means, 314 ... Table reference means, 321 ... Over-stage information table .

Claims (3)

A wireless communication system comprising a master unit and a plurality of slave units wirelessly connected in a multi-stage hierarchy with the number of stages limited to the master unit,
The slave is
A message telegram receiving means for receiving a message telegram from the subordinate terminal to the center device;
Based on the report route information to the own terminal in the report message received by the report message reception means, the number of stages over detection means for detecting the number of stages over;
When the over-stage detection means detects an over-stage number, the over-stage information storage means for storing the over-stage information consisting of the notification route information and the terminal ID of the notification terminal in the notification message in the storage unit in the terminal,
Route information processing means for rewriting the report route information in the report message to only the report route information of the terminal;
A wireless communication system. The wireless communication system according to claim 1, wherein
When the slave unit receives a request message from a center device to a subordinate terminal, if the information on the number of steps over the subordinate terminal is held in the storage unit, the slave unit receives the information from the notification route information of the number of oversteps information. A wireless communication system for resetting the request route information of the requested message. The wireless communication system according to claim 1 or 2,
The slave unit that has detected the over-stage number by the over-stage number detection means broadcasts the over-stage number information to surrounding terminals, and the slave unit that has received the over-stage number information stores the over-stage number information in its own storage unit. A wireless communication system for storing.

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