JP2006339762A - Wireless terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for executing an electric field strength test between slave units while preventing crosstalk and determining a communication destination (relay slave unit) in response to the electric field strength in a remote supervisory system. <P>SOLUTION: A transmission side slave unit A21 transmits a test signal to the other slave units A11 to A13, the other slave units A11 to A13 for receiving the test signal detect the electric field strength of the test signal and transmit a return signal to the transmission side slave unit A21. In this case, the other slave units A11 to A13 delay the transmission timing of the return signal in response to the detected electric field strength. The transmission side slave unit A21 discriminates the electric field strength of the test signal in the return signal sender slave units A11 to A13 on the basis of delay information of the return signal and registers the two receiver side slave units A11, A12 in the order of, e.g. greater electric field strength as a reception destination slave unit. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wireless terminal device used in a remote monitoring system such as an automatic meter reading of a gas or a water meter or a fire or abnormality monitoring.

  Conventionally, systems such as automatic meter reading of gas and water meters or remote monitoring of fires and abnormalities are known, but in this system, for example, the center device sends various request signals to the master unit, The master unit transmits a request signal from the center device to each wireless terminal device (also referred to as a slave unit), and the slave unit is connected to the water supply, gas meter, or sensor, and receives the detection signal in response to the request signal. The master unit transmits a detection signal of each slave unit to the center unit, and the center unit performs centralized management of monitoring data and the system.

  Specifically, for example, in meter reading of household gas and water meters, a slave unit is arranged near the installed meter, and meter reading data acquired on the slave unit side is transmitted to the master unit. It is transmitted to the center device via the telephone line network. The center device performs tasks such as issuing an invoice for the amount used based on the transmitted meter reading data.

  In such a remote monitoring system, when the master unit and the slave unit are installed, a test is performed to check whether communication is properly performed between the slave unit and the master unit. For example, when the slave unit and the master unit are installed at the mounting position, the test radio wave (test signal) is transmitted by pressing the radio wave test button attached to the slave unit. Radio waves are transmitted from the unit to the slave unit, and the strength of the electric field strength of the radio wave is displayed on the slave unit side as strong, medium, or weak, for example, depending on the number of blinking LEDs of the three LEDs. And checking whether or not wireless communication between the parent device and the child device is normally performed (see Patent Document 1).

  This system detects the strength of the electric field strength during communication between the two from the viewpoint of whether the communication between the master unit and the slave unit is properly performed. As a result, when an appropriate electric field strength cannot be secured between the parent device and the child device, it is conceivable to appropriately take measures such as installing a relay device.

  For example, in the wireless terminal device disclosed in Patent Literature 2, when meter reading data from a meter is transmitted to a center device via a wireless terminal device (corresponding to a slave unit), a relay station (corresponding to a master unit), and an exchange. If the wireless terminal device cannot perform wireless communication with the relay station, make a call to the other wireless terminal device, and transmit the data to the relay station via the other wireless terminal device, Data from the meter can be reliably transmitted to the center device via a wireless circuit without being affected by the installation location of the wireless terminal device (see Patent Document 2).

  As described above, in the system described in Patent Document 1, when the electric field strength capable of performing proper communication between the parent device and the child device cannot be obtained, for example, as described in Patent Document 2, between the child devices It is conceivable that the signal is transmitted to the master unit by relaying the slave unit in that case, but in that case, communication is also performed between specific slave units as in the case of the master unit and the slave unit. Sometimes it is necessary to test at the time of installation whether the required electric field strength can be obtained.

  Therefore, in order to know the electric field strength at the receiving handset when a signal is sent from a specific handset to another handset, a test signal is sent all at once from the specific handset to another handset (broadcast). Then, each of the other slave units that have received the test signal returns a reply signal to the specific slave unit (transmission side slave unit). Here, since there are a large number of slave units on the receiving side unlike the master unit, replies are also sent simultaneously from a large number of slave units.

  In such a case, the transmission slave unit of the reply signal that arrives first can be selected as the communication partner of the specific slave unit. However, it is desirable that the communication route from the child device to the parent device is performed along a route where a stronger electric field strength is obtained, and it is assumed that the transmission destination child device along the communication route where the strongest electric field strength is obtained. Even if it can be set, normal communication may not be possible due to subsequent changes in the communication environment, etc. It is desirable to set it.

  However, if reply signals are sent to the transmitting slave unit at the same time, there is a risk of interference on the receiving side of the reply signal, that is, the transmitting side slave unit of the test signal. When the first reply signal is received, even if a reply signal from another slave unit arrives during the reception process, it cannot be received. Therefore, the reply received accidentally when the reception process of the first received signal is completed. The signal is not limited to the second incoming signal, and it cannot be determined what number the received signal actually received. That is, it cannot be determined whether the second received reply signal is received second. In the first place, the electric field strength of the test signal in the transmission slave unit of the first reply signal is not always the strongest. Therefore, on the side of the slave unit (transmitting side slave unit) that transmitted the test signal, for example, even if trying to register the communication partner slave unit in the order of strong electric field strength, there is a problem that it is not known which slave unit should be registered. .

Thus, if the strength of the electric field strength in the communication between the slave units is not known, when communication is performed between the master unit and the slave unit using the slave unit as a relay unit, it is impossible to set the optimum communication route. . In other words, the optimum communication route between the parent device and the child device is set by transmitting the electric field strength information acquired on the child device side to the center device via the parent device and collecting it by the center device (for example, the management server of the center device). However, it is performed in consideration of other communication route information, which will be described later, but if the transmission side slave unit cannot collect the reception field strength information of the communication partner slave unit, the center device cannot set the optimum communication route. Problems arise.
JP 2004-341648 A JP 2001-217947 A

  The present invention has been made in view of such problems, and its purpose is to communicate between slave units when the slave unit communicates with the master unit by relaying another slave unit in communication between the master unit and the slave unit. For route setting, when transmitting a test signal from a transmitting slave unit, the transmitting slave unit can receive a reply signal transmitted from a plurality of receiving slave units without interference, and It is to be able to accurately grasp the electric field strength of each communication route in the communication between slave units, and as a result, the communication route between the master unit and the slave unit can be set accurately. Is to do.

The invention of claim 1 can be used in a remote management system comprising a plurality of wireless terminal devices, a parent device communicatively connected to the wireless terminal device, and a center device communicatively connected to the parent device. A wireless terminal device that receives a test signal transmitted by another wireless terminal device, a device that transmits a reply signal to the wireless terminal device when the test signal is received, and an electric field strength of the received signal. It is characterized by comprising means for detecting and means for delaying transmission of the reply signal in accordance with the detected electric field strength.
According to a second aspect of the present invention, in the wireless terminal device according to the first aspect, the reply signal is transmitted only when the electric field strength reaches a predetermined level.
The invention of claim 3 can be used in a remote management system comprising a plurality of wireless terminal devices, a parent device communicably connected to the wireless terminal device, and a center device communicably connected to the parent device. A wireless terminal device for transmitting a test signal, a means for receiving a reply signal transmitted from another wireless terminal device that has received the test signal, and a wireless terminal device that has transmitted the reply signal And means for performing.
According to a fourth aspect of the present invention, in the wireless terminal device according to the third aspect, the return signal receiving means receives only a return signal that arrives within a predetermined time from the test signal transmission.
The invention of claim 5 can be used in a remote management system comprising a plurality of wireless terminal devices, a parent device communicatively connected to the wireless terminal device, and a center device communicatively connected to the parent device. A wireless terminal device that transmits a test signal, a device that receives a test signal transmitted by another wireless terminal device, and a test signal that is transmitted by another wireless terminal device. Means for transmitting a reply signal to a transmission source wireless terminal device; means for detecting the electric field strength of the received test signal; means for delaying transmission of the reply signal according to the detected electric field strength; and another wireless terminal It is characterized by comprising means for receiving a reply signal transmitted from the apparatus and means for registering a transmission source wireless terminal apparatus of the reply signal.

According to the present invention, when the reception field strength in the reception-side wireless terminal device when the test signal is broadcast from the transmission-side wireless terminal device is transmitted to the transmission-side wireless terminal device, the reception-side wireless terminal device with strong electric field strength Since the transmission timing of the reply signal is delayed according to the electric field strength so that the reply signal can be received first, interference can be avoided even if replies are received from a large number of receiver wireless terminals, and each receiver wireless terminal It is possible to accurately determine the strength of the electric field strength in the apparatus.
In addition, when the electric field strength of the received signal is less than the predetermined value, no reply is made, and no reply signal is received after a predetermined time has elapsed, so there is no unnecessary communication and the communication cost is reduced. Can be reduced.

An embodiment of a handset that is a wireless terminal device according to the present invention will be described.
FIG. 1 is a block diagram schematically showing a system to which the slave unit of this embodiment can be applied.
This system includes, for example, automatic meter reading of gas and water meters, or remote monitoring systems such as monitoring of fires and abnormalities, that is, a slave unit that is a wireless terminal device provided in each monitoring device (meter, etc.) A remote monitoring system comprising a parent device that manages a child device, receives monitoring data from the child device, transmits the monitoring data to the center device 30, and a center device 30 that centrally manages monitoring data from a plurality of parent devices. Yes, as shown in the figure, a plurality of wireless terminal devices A11 to A22 and A11 'to A22' that are wirelessly connected to and managed by the parent devices 20 and 20 ', and the parent devices 20 and 20', for example, are portable The center device 30 is connected via a wireless communication network N such as a telephone line.

  In this remote monitoring system, each child device 10, the parent device 20, and the center device 30 are connected so as to be able to perform data communication in both directions, and each child device 10 and the parent device 20 have already been described. In this way, it is connected directly or via another slave unit 10.

FIG. 2 is a block diagram schematically showing the configuration of the slave unit according to the embodiment of the present invention.
As illustrated, the slave unit 10 includes a wireless transmission / reception unit 12 and an antenna 14 for performing wireless communication with another slave unit 10 or the master unit 20, and an I / F unit 15 connected to a meter, a sensor, or the like (not illustrated). And a storage unit 16 composed of a ROM for storing the operation program of the slave unit 10 and a RAM for temporarily recording processing data, etc., and a control unit 18 for controlling the entire slave unit 10 and performing arithmetic processing. .

  The slave unit 10 reads a test signal message stored in the storage unit 16 by operating a test signal transmission button, for example, at the time of setting, and waits for another reception from the wireless transmission / reception unit 12 via the antenna 14. In addition to transmitting to the slave unit in the middle, it also has a function of receiving a return signal transmitted from the test signal receiving side slave unit 10 and registering the slave unit information that has transmitted the return signal. At the same time, when a test signal is received from another slave unit 10, a function for reading a telegram of a predetermined reply signal from the recording unit 16 and returning it to the transmitting side slave unit 10, and the received test signal When the return electric field strength is detected and the reply signal is sent back to the transmitting side slave unit 10, the reply timing is delayed according to the detected electric field strength.

  Here, when the slave unit receives the telegram broadcast from the transmitting side slave unit and detects the electric field strength of the signal, for example, a data table (field strength and delay time stored in its own storage device) is detected. Refer to the control table (see FIG. 4) or calculate the delay time according to the electric field strength according to the function t = f (x) stored in advance (where t is the delay time and x represents the electric field strength of the received signal). Then, it is delayed by the delay time, and at that time, its own identification code is given and a reply signal is transmitted.

FIG. 3 shows an operation flow of the transmission side slave unit described above.
First, the transmitting-side slave unit 10 adds its own ID (identification information) to the broadcast message read from the storage unit 16 for transmission (broadcast) (S101), waits for a response from another slave unit for a predetermined time, If there is no reception response within the predetermined time and a timeout occurs (S102, YES), the processing is terminated assuming that there is no communication partner child device (S102). If there is a reception response (S103, YES) within a predetermined time (S103, YES), and if a response message is received (S104), processing for registering the information (ID) of the reply signal source slave unit in its own storage means (S105). If there is no reception response in step S103 (S103, NO), a response is waited until timeout.
Here, the predetermined time refers to the time corresponding to the lowest level (for example, level 3) of the electric field strength at which normal communication is possible. That is, if there is an incoming call within a predetermined time, it means that the electric field strength of the test signal in the transmission slave unit is equal to or higher than the lowest level at which communication is possible.

FIG. 4 shows an operation flow of the reception side slave unit.
First, the receiving side slave unit 10 is set in a reception waiting state (S201, YES). When a test signal is received in this state, the reception side field device 10 acquires or detects the field strength of the received signal (S202). On the basis of the above, referring to the table or calculating based on the function as described above, a delay time is generated (S203), and waiting for the delay time to elapse, that is, when the delay time elapses (S204), The message is sent with its own ID (S205).

FIG. 5 is a diagram for explaining a procedure for setting the communication route between the slave unit and the master unit by applying the slave unit to the remote monitoring system. Here, the subunit | mobile_unit is represented by code | symbol A11-A33.
First, in FIG. 5A, the slave units A11 to A33 are slave units that can communicate with the master unit 20 directly or indirectly. In setting a communication route with the master unit 20, first, a test signal is transmitted from each of the slave units A11 to A33 to the master unit 20 in the same manner as described in Patent Document 1, for example. In response to the test signals from the slave units A11 to A33, a reply signal is transmitted, and the strength of the reply signal is detected on the slave unit side.

In the illustrated example, the communication electric field strength of communication between the slave units A11 to A13 and the master unit 20 is level 7 for the slave unit A11, level 5 for the slave unit A12, level 4 for the slave unit A13, and level 2 for the slave unit A23. In the slave units A21 to A33, the electric field strength is not detected. Here, it is assumed that electric field strength level 3 is a reference value, and normal communication is possible if the electric field strength is higher than this level, and normal communication is impossible if the electric field strength is lower than that level.
The handset A23 is level 2, and the handset A21 to A33 cannot detect the electric field strength, so any direct communication is impossible.
Therefore, the slave units A11 to A13 register that the communication partner is the master unit in each storage unit 16 and notify the master unit 20 of the fact.

Next, as shown in FIG. 5B, the slave units A11 to A13 that have registered the master unit 20 as the communication destination are set in a test signal reception standby state, and it is determined that direct communication with the master unit 20 is impossible as shown in FIG. When the test signal is transmitted from the device A21, the slave devices A11 to A13 send back a predetermined signal (reply signal) with a delay according to the reception strength of the test signal.
Accordingly, the slave unit A21 can determine the electric field strength of the test signal in the receiver unit from the time lag of the received signal. That is, in this example, the slave unit A21 determines that the received electric field strength level of the test signal is 7 because the slave unit A11 has returned from the slave unit A11 without a delay time. Since the reply from the slave unit A12 arrives with a delay of 0.0200 S (seconds) from the slave unit A21, it is determined that the communication electric field strength to the slave unit A12 is level 5 from the delay time. Here, since the determined electric field strengths both exceed the reference value level 3, the two slave units are registered in the recording unit 16 of the slave unit A21 as communication counterparts, and the slave unit A11 is the main unit here. And the slave unit A12 as a sub-communication partner, the base station 20 is notified through the slave unit A11 or A12 together with the received electric field strength. In this case, after only the top two electric field strengths are registered, replies from other slave units are set to be ignored. Accordingly, the reply from the slave unit A13 is ignored. Further, the slave unit A21 that has completed the registration next enters a standby state for receiving a test signal from another slave unit.

In this way, the remaining child devices are also checked for communication electric field strength with other child devices in the same manner as the child device A13, and the upper two child devices are registered as communication destinations for each electric field strength. The slave unit that has completed registration in this way is in a standby state for receiving a test signal from another slave unit.
By repeating this operation up to the last child device, for example, other two child devices are registered as communication destinations in all child devices that cannot directly communicate with the parent, and the parent device 20 and the child device 10 as shown in FIG. A communication route (a main route indicated by a solid line and a sub route indicated by a broken line) based on the electric field strength is formed. For example, the child device A31 has the child device A31 → the child device A21 as a main route and the child device A31 → the child device A22 as a sub route.
Note that the receiving side slave unit can also send a reply signal only when the received signal is at a predetermined level (for example, level 3) or higher, and the transmitting side slave unit 10 can receive an incoming call within a predetermined time. It is also possible to register all the reply signal transmission slave units 10 that have been sent and transmit them to the center device 30 via the master unit 20 and use it as a judgment material when setting the optimum route on the center device side.

FIG. 6 shows an example of route management information created and registered based on the response slave unit information transmitted from the transmission side slave unit.
After the route management information is created and registered, the main route (first route) is preferentially communicated based on this route management information, and as described above, when the main route has trouble, the sub route Communication is performed on the (second route).

  The center device 30 acquires route information indicating the communication state in the communication route of each child device from the parent device 20, manages this in the storage unit 31, determines a communication route based on the route information, and determines the communication route. Set for each slave unit.

In order to select a route, the child device and the parent device are provided with means for detecting a communication state in the route, and from this detection result, the route information indicating the communication state of each route is sent to the center device 30 that manages this information. You can be notified.
The center device 30 receives route information of all routes that can communicate with each of the child devices A11 to A33 from the parent device 20, and stores the received route information in the storage unit 31 for management. The route information is based on the communication state (electric field strength, noise level, number of communication errors, etc.) between the slave unit and the route from the specific transmitter unit to the master unit 20 as basic information. In addition, the center device 30 can grasp route information including the number of slave units relayed in each route, the frequency of use of each slave device as a repeater, and manage the route information for each route. The data is stored in the storage unit 31 in a form.

The optimum route is determined in consideration of the requirements shown in the following (1) to (4), for example, in addition to the electric field strength of the route (a higher strength is given priority).
(1) Route noise level (priority with lower noise level)
(2) Slave unit communication error or error rate count value (priority with lower number of errors)
(3) The number of slave units that are routed through (priority is given to the smaller number of slave units)
(4) Usage as a relay device in the slave unit that passes through (priority is given to the one with lower usage)

  FIG. 7 is a diagram for explaining the optimum route review and the optimum route change operation. If the electric field strength (level 7) of the route to the child device A12 initially deteriorates to, for example, the electric field strength (level 4) due to a change in environment around the route or a change in characteristics of the child device A12, the child device X sends route information indicating that the electric field strength of the route to the child device A 12 has decreased to level 4 to the center device 30 via the parent device 20. Receiving this route information, the center device 30 reviews the route to the child device A12, determines the route to the child device A21 as the optimum route, and changes and corrects the optimum route set in the child device X according to this decision. .

It is a block diagram which shows roughly the system which the subunit | mobile_unit of this embodiment is applicable. It is a block diagram which shows roughly the structure of the subunit | mobile_unit which concerns on one Embodiment of this invention. Shows the processing flow of the sending slave unit The processing flow of the receiving side slave unit is shown. It is a figure explaining the procedure which sets the communication route of a subunit | mobile_unit and a main | base station by applying the said subunit | mobile_unit to a remote monitoring system. An example of route management information created and registered based on the response slave unit information transmitted from the transmission side slave unit is shown. FIG. 7 is a diagram for explaining the optimum route review and the optimum route change operation.

Explanation of symbols

  10 (A11 to A33) ... slave unit (wireless terminal device), 12 ... wireless transmission / reception unit, 14 ... antenna, 15 ... interface unit, 16 ... storage unit, 18 ... control , 20... Master device, 30... Center device, 31.

Claims (5)

A wireless terminal device usable in a remote management system comprising a plurality of wireless terminal devices, a parent device communicably connected to the wireless terminal device, and a center device communicably connected to the parent device. ,
Means for receiving a test signal transmitted by another wireless terminal apparatus; means for transmitting a return signal to the wireless terminal apparatus when receiving the test signal; means for detecting the electric field strength of the received signal; Means for delaying transmission of the reply signal according to the strength. The wireless terminal device according to claim 1,
The wireless terminal device transmits the reply signal only when the electric field strength reaches a predetermined level. A wireless terminal device usable in a remote management system comprising a plurality of wireless terminal devices, a parent device communicably connected to the wireless terminal device, and a center device communicably connected to the parent device. ,
Means for transmitting a test signal, means for receiving a reply signal transmitted from another wireless terminal device that has received the test signal, and means for registering a wireless terminal device that has transmitted the reply signal A wireless terminal device. The wireless terminal device according to claim 3,
The wireless terminal apparatus, wherein the reply signal receiving means receives only a reply signal that arrives within a predetermined time from the test signal transmission. A wireless terminal device usable in a remote management system comprising a plurality of wireless terminal devices, a parent device communicably connected to the wireless terminal device, and a center device communicably connected to the parent device. ,
A means for transmitting a test signal, a means for receiving a test signal transmitted by another wireless terminal device, and a test signal transmitted by another wireless terminal device, when a test signal transmitted by another wireless terminal device is received, a reply signal to the test signal transmission source wireless terminal device Means for transmitting, means for detecting the electric field strength of the received test signal, means for delaying transmission of the reply signal according to the detected electric field strength,
A wireless terminal apparatus comprising: means for receiving a reply signal transmitted from another wireless terminal apparatus; and means for registering a transmission source wireless terminal apparatus of the reply signal.

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