JP2014150458A - Remote meter reading communication terminal and remote meter reading communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a remote meter reading communication terminal and remote meter reading communication system capable of identifying illegal disturbing waves out of the radio law.SOLUTION: A pattern storage 1j previously stores signal generation patterns which are prescribed by the radio law on the communication made in a frequency band used by a transmission/reception section 1b. The signal generation pattern is a legal pattern which alternately repeats a permission period in which transmission of a radio wave signal is permitted and an inhibition period in which transmission of the radio wave signal is inhibited, and prescribes the time length of the permission period and the inhibition period. When the generation pattern of a disturbing wave received by the transmission/reception section 1b coincides with the legal pattern, a disturbing wave determination section 1h determines that the disturbing wave included in the communication is made based on the radio law, and when the generation pattern of a disturbing wave received by the transmission/reception section 1b does not coincide with the legal pattern, the disturbing wave determination section 1h determines that the disturbing wave included in the communication is made out of the radio law.

Description

  The present invention relates to a remote meter reading communication terminal and a remote meter reading communication system.

  Conventionally, a remote meter-reading system is configured by providing a remote meter-reading communication terminal to a customer who uses a supply medium supplied from a supplier. The remote meter reading communication terminal wirelessly transmits the meter reading information obtained by measuring the amount of supply medium used to the master station installed by the supplier, the handy terminal carried by the meter reader, etc. The usage amount is notified to the supplier (see, for example, Patent Document 1). Note that the supply medium includes electric power, water, gas, and the like.

JP2011-250301A

  The frequency band that the remote meter reading communication terminal uses for wireless communication is the 920 MHz band, and other communication terminals such as HEMS (Home Electrical Management System) devices, sensor devices, and tags are also used for communication. Therefore, if many communication terminals are communicating in the same frequency band, and another communication terminal communicates at the same time when communicating with the remote meter reading communication terminal, the radio signal transmitted by the other communication terminal is disturbed. There is a possibility of congestion and interference in the form of waves, and the communication of the remote meter reading communication terminal may fail.

  However, communication performed by a communication terminal is usually based on the Radio Law, and the radio signal transmitted by such a communication terminal is legal. Therefore, although the communication failure of the remote meter reading communication terminal temporarily occurs, this communication failure will eventually be solved.

  However, communication terminals that generate illegal radio signals that are not based on the Radio Law, whether intentional or unintentional, in the frequency band used for remote meter reading communication terminals, and vending machines, microwave ovens, etc. There is equipment. The radio signal generated by these communication terminals and devices becomes a disturbing wave for the remote meter reading communication terminal, and the remote meter reading communication terminal may fail to communicate. And since it is an illegal interference wave which is not based on the Radio Law, there is a possibility that a communication failure in which the communication of the remote meter reading communication terminal fails frequently or continues.

  The remote meter-reading communication terminal transmits meter-reading information in order for the supplier to charge the usage fee of the supply medium to the customer, and communication troubles due to illegal interference waves must be avoided.

  The present invention has been made in view of the above reasons, and an object thereof is to provide a remote meter reading communication terminal and a remote meter reading communication system that can identify illegal interference waves that are not based on the Radio Law. It is in.

  The remote meter-reading communication terminal of the present invention is a remote meter-reading communication terminal that includes a transmission / reception unit that transmits and receives radio signals, and transmits meter-reading information representing the usage amount of a supply medium supplied from a supplier. A pattern storage unit that stores in advance a signal generation pattern defined by the Radio Law for communications performed in a frequency band used by the transceiver, and when an interference wave is generated, the interference wave is applied to the Radio Law. An interference wave determination unit that determines whether or not the communication is based on communication, the signal generation pattern alternately includes a permission period in which transmission of a radio signal is permitted and a prohibition period in which transmission of the radio signal is prohibited Repeatedly, each time length of the permission period and the prohibition period is defined, and the interference wave determination unit determines that the generation pattern of the interference wave received by the transmission / reception unit matches the signal generation pattern. When the interference wave is determined to be due to communication based on the Radio Law, and the generation pattern of the interference wave received by the transceiver does not match the signal generation pattern, the interference wave is based on the Radio Law It is characterized in that it is determined that the communication is not due to communication.

  In this invention, an interference wave time storage unit that stores the time when the interference wave is received, a failure time storage unit that stores a time when reception of the radio signal by the transmission / reception unit fails, and a radio signal received by the transmission / reception unit A difference between the time when the reception failed and the time when the interference wave was received is equal to or less than a predetermined time, and the strength of the radio signal at the time when the reception failed is predetermined. When it is higher than the strength, it is preferable that the reception failure includes a communication failure determination unit that determines that the interference is caused by the interference wave.

  A communication system for remote meter reading according to the present invention comprises a plurality of communication terminals for remote meter reading according to the present invention and a master station that performs communication between the communication terminals for remote meter reading.

  In the present invention, when the remote meter-reading communication terminal detects an interference wave, the remote meter-reading communication terminal transmits information on the jamming wave to the master station, and the master station transmits the remote meter-reading communication terminal from each of the remote meter-reading communication terminals. It is preferable to specify the position of the source of the interference wave based on the information on the interference wave.

  In the present invention, when the remote meter-reading communication terminal detects an interference wave, the remote meter-reading communication terminal transmits information related to the disturbing wave to the other remote meter-reading communication terminal, and is transmitted from the other remote meter-reading communication terminal. If a jamming wave is received, the location of the source of the jamming wave is specified based on information on the jamming wave detected by the terminal and information on the jamming wave transmitted from the other remote metering communication terminal. And it is preferable to transmit the information on the position of the specified source of the disturbing wave to the master station.

  As described above, the present invention has an effect that it is possible to identify illegal interference waves that are not based on the Radio Law.

It is a block diagram which shows the system configuration | structure of embodiment. It is a sequence diagram which shows an example of communication same as the above. It is a table figure which shows a packet communication record same as the above. (A)-(d) It is explanatory drawing which shows the signal generation pattern same as the above. It is a table figure which shows disturbance reception recording same as the above. It is a block diagram which shows the system configuration | structure using the several communication terminal for remote meter-reading same as the above. It is a table figure which shows the reception log | history of a failure generation notification same as the above.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment)
FIG. 1 shows a configuration of a remote meter reading communication terminal 1. The remote meter-reading communication terminal 1 includes an antenna 1a, a transmission / reception unit 1b, a demodulation unit 1c, a modulation unit 1d, an RSSI unit 1e, an arithmetic processing unit 10, and a storage unit 11. The arithmetic processing unit 10 is configured by a CPU (Central Processing Unit) and has functions of a signal processing unit 1f, a reception success / failure determination unit 1g, an interference wave determination unit 1h, and a communication failure determination unit 1i. The storage unit 11 includes a pattern storage unit 1j and a reception state storage unit 1k.

  The remote meter reading communication terminal 1 is provided in a consumer who uses a supply medium supplied from a supplier, and wirelessly communicates with a master station 2 installed by the supplier, a handy terminal 3 carried by a meter reader, and the like. Communicate. Then, the remote meter-reading communication terminal 1 acquires meter-reading information obtained by metering the amount of supply medium from a meter-reading meter (not shown) and transmits it to the master station 2, the handy terminal 3, etc. The usage amount is notified to the supplier. The remote meter-reading communication terminal 1 is configured to directly communicate with the master station 2 and the handy terminal 3, or the multi-hop between the master station 2 and the handy terminal 3 using another remote meter-reading communication terminal 1 as a relay station. Any configuration that performs communication may be used. Note that the supply medium includes electric power, water, gas, and the like.

  Hereinafter, the operation of the remote meter reading communication terminal 1 will be described.

  The transmission / reception unit 1b performs transmission / reception of radio signals via the antenna 1a. Then, the demodulator 1c performs demodulation processing on the received radio signal. The signal processing unit 1f acquires a message from the demodulated signal, and based on the acquired message, each process such as an acquisition process of meter reading information, a process of transmitting meter reading information, and a response signal (ACK) reply based on the acquired meter I do. The signal processing unit 1f generates a signal to be transmitted and outputs the signal to the modulation unit 1d. The modulation unit 1d performs modulation processing on the transmission signal. The transceiver 1b outputs the signal received from the modulator 1d as a radio signal from the antenna 1a.

  The RSSI unit 1 e converts the radio signal received by the transmission / reception unit 1 b into an RSSI (Received Signal Strength Indicator) signal and outputs the signal to the arithmetic processing unit 10. The RSSI signal is a signal whose voltage changes according to the signal level of the received radio wave signal. For example, the voltage increases as the signal level increases.

  Further, when the signal demodulated by the demodulator 1c is addressed to its own terminal (including unicast, broadcast, and multicast), the reception success / failure determination unit 1g receives the signal addressed to this terminal. Determine if successful. Specifically, if the signal processing unit 1f succeeds in acquiring a message from the signal addressed to the terminal itself, the reception success / failure determination unit 1g determines that the reception is successful. When the signal processing unit 1f fails to acquire a message from the signal addressed to the terminal itself, the reception success / failure determination unit 1g determines that the reception has failed.

  Then, the reception success / failure determination unit 1g stores the reception success / reception failure determination result in the reception state storage unit 1k as a packet reception record.

  For example, it is assumed that the communication shown in FIG. 2 is performed between the remote meter-reading communication terminal 1 and the handy terminal 3. First, the handy terminal 3 transmits a packet P1 to the remote meter reading communication terminal 1, and the remote meter reading communication terminal 1 that has successfully received the packet P1 returns a response signal A1 to the handy terminal 3. Next, the handy terminal 3 transmits the packet P2 to the remote meter reading communication terminal 1, and the remote meter reading communication terminal 1 fails to receive the packet P2. Thereafter, the handy terminal 3 transmits the packet P3 to the remote meter reading communication terminal 1, and the remote meter reading communication terminal 1 also fails to receive the packet P3.

  In this case, the packet reception record shown in FIG. 3 is stored in the reception state storage unit 1k. The packet reception record is composed of items of reception success / failure of the packet addressed to the terminal (reception success: ◯, reception failure: ×), reception time, and received signal strength. In the reception success / failure item, a reception success / reception failure determination result by the reception success / failure determination unit 1g is stored. The reception time item stores the time when the packet is received. In the item of received signal strength, the received signal strength at the reception time of the packet is set based on the RSSI signal output by the RSSI unit 1e.

  Further, when an interference wave is generated, the interference wave determination unit 1h determines whether the interference wave is due to communication based on the Radio Law. The interference wave is a signal that cannot be synchronized in the signal processing unit 1f, a signal that is not addressed to the terminal itself, or the like.

  Here, various agreements are defined for communication by the Radio Law. The transmitter / receiver 1b performs communication using the 920 MHz band. For communication using the 920 MHz band, for example, according to the presence or absence of carrier sense and the length of the carrier sense time, for example, FIG. It is specified that the transmission time limit shown in c) is provided.

  FIG. 4A alternately repeats a permission period T11 of 100 msec in which transmission of radio signals is permitted and a prohibition period T12 of 100 msec in which transmission of radio signals is prohibited.

  In FIG. 4B, a 4 sec permission period T21 in which transmission of radio signals is permitted and a 50 msec inhibition period T22 in which transmission of radio signals is prohibited are alternately repeated.

  In FIG. 4C, a 400 msec permission period T31 permitted to transmit radio signals and a 2 msec prohibition period T32 prohibited to transmit radio signals are alternately repeated.

  The pattern storage unit 1j stores in advance each information (legal pattern which is a signal generation pattern defined by the Radio Law) of the permission period and the prohibition period shown in FIGS. 4 (a) to 4 (c).

  Then, when an interference wave is generated, the interference wave determination unit 1h refers to the legal pattern stored in the pattern storage unit 1j and determines whether the interference wave is due to communication based on the radio wave law. . The type of legal pattern may be other than those shown in FIGS. 4 (a) to 4 (c).

  Specifically, the interference wave determination unit 1h determines the generation pattern of the interference wave from the RSSI signal output from the RSSI unit 1e. The generation pattern of the interference wave is classified according to characteristics such as a time length in which the interference wave is generated and a time interval in which the interference wave is generated. Then, the interference wave determination unit 1h determines which of the legal patterns stored in the pattern storage unit 1j matches the generation pattern of the interference wave. When the generation pattern of the interference wave matches any legal pattern stored in the pattern storage unit 1j, the interference wave determination unit 1h is based on communication based on the radio wave law (interference signal) The wave is legal). Further, when the interference wave generation pattern does not match any legal pattern stored in the pattern storage unit 1j, the interference signal determination unit 1h does not receive the interference signal based on communication based on the Radio Law. It is determined that the disturbing wave is illegal. For example, the generation pattern of the interference wave that does not match the legal pattern includes a pattern in which radio signals are continuously output without providing a prohibition period, as shown in FIG.

  Then, the interference wave determination unit 1h stores the determination result as to whether the received interference wave is legal or illegal in the reception state storage unit 1k as an interference reception record. In other words, by determining whether the generation pattern of the interference wave matches the legal pattern by the interference wave determination unit 1h, it is possible to identify an illegal interference wave that is not based on the Radio Law.

  For example, when the communication shown in FIG. 2 is performed between the remote meter-reading communication terminal 1 and the handy terminal 3, it is assumed that the interference waves I1 and I2 are generated. The jamming wave I1 occurs immediately before the handy terminal 3 transmits the packet P2, and the jamming wave I2 occurs immediately after the handy terminal 3 transmits the packet P2.

  In this case, the interference reception record shown in FIG. 5 is stored in the reception state storage unit 1k. The jamming reception record is composed of items such as a legal / illegal judgment result of a jamming wave, a reception time, and a received signal strength. The legal / illegal item of the jamming wave stores the legal / illegal judgment result by the jamming wave judging unit 1h. The reception time item stores the time when the jamming wave is received. In the item of received signal strength, the received signal strength at the reception time of the jamming wave is set based on the RSSI signal output by the RSSI unit 1e.

  The communication failure determination unit 1i receives the signal when the difference between the time when the reception is failed and the time when the jamming wave is received is 30 seconds or less and the received signal strength at the time when the reception fails is −95 dBm or more. It is determined that the failure is caused by an interference wave. That is, the communication failure determination unit 1i determines that the cause of reception failure despite the high received signal strength is an interference wave generated in the vicinity of the reception failure time. Here, the disturbing wave time storage unit, the failure time storage unit, and the signal strength storage unit of the present invention are configured by a reception state storage unit 1k (packet reception record and jamming reception record). In addition, each value of 30 seconds and -95 dBm used for this determination process is an example, and may be set as appropriate according to the configuration, environment, and the like.

  Specifically, referring to the packet reception record (FIG. 3) and the disturbance reception record (FIG. 5), the reception time of the packet P2 that failed to receive: 14:12:30, the reception time of the illegal interference wave I1: 14:12 The reception time of the illegal interfering wave I2 is 14:13:00. That is, the interference waves I1 and I2 are generated within 30 seconds before and after the reception time of the packet P2. Further, the received signal strength of the packet P2 is -89 dBm. That is, the received signal strength of the packet P2 is −95 dBm or more. Therefore, the communication failure determination unit 1i determines that the failure to receive the packet P2 is caused by the illegal interference waves I1 and I2.

  Further, referring to the packet reception record (FIG. 3) and the disturbance reception record (FIG. 5), the reception time of the packet P3 that failed to be received: 14:15:00, the reception time of the illegal interference wave I1: 14:12:00 Second, the reception time of the illegal interfering wave I2: 14:13:00. That is, the interference waves I1 and I2 are not generated within 30 seconds before and after the reception time of the packet P3. Further, the received signal strength of the packet P3 is −106 dBm. That is, the received signal strength of the packet P3 is less than -95 dBm. Therefore, the communication failure determination unit 1i determines that the reception failure of the packet P3 is not caused by an illegal interference wave but is caused by insufficient received signal strength.

  Therefore, since the cause of the reception failure is specified by the communication failure determination unit 1i, the supplier can execute countermeasures and countermeasures against the reception failure according to the cause of the reception failure.

  When the communication failure determination unit 1i determines that a communication failure due to an illegal interference wave has occurred, the arithmetic processing unit 10 sends a communication failure occurrence notification (failure occurrence notification) due to the illegal interference wave to the master station 2. Send. The failure notification includes information such as the identification information of the remote remote meter reading communication terminal 1, the reception time of the illegal interference wave, and the received signal strength of the illegal interference wave.

  As shown in FIG. 6, the master station 2 constitutes a remote meter reading communication system together with a plurality of remote meter reading communication terminals 1 under its control. In FIG. 6, in order to distinguish the plurality of remote meter reading communication terminals 1 from each other, the remote meter reading communication terminals 1A, 1B, 1C,. . . . . . The symbol is attached.

  Then, when receiving the failure occurrence notification from each remote meter-reading communication terminal 1, the master station 2 creates a failure occurrence notification reception history shown in FIG. The master station 2 includes communication terminals 1A, 1B, 1C,. . . . . . Are identified in advance, and the position of the source of the illegal interfering wave is specified based on the reception time and the received signal intensity of the illegal interfering wave in each remote meter-reading communication terminal 1. For example, in the failure occurrence notification reception history shown in FIG. 7, the remote meter reading communication terminals 1A, 1B, 1C, 1E, 1G, and 1H have received illegal interference waves at the same time, and the remote meter reading communication terminal 1A, The received signal strength in 1B is the highest. Therefore, the master station 2 determines that there is an illegal interference wave source between the remote meter reading communication terminals 1A and 1B, and notifies the supplier to that effect. Accordingly, the supplier can take measures and countermeasures against the source of the illegal interference wave based on the content notified from the master station 2.

  In a configuration in which the remote meter-reading communication terminal 1 performs multi-hop communication using another remote meter-reading communication terminal 1 as a relay station, the remote meter-reading communication terminal 1 may operate as follows. The remote meter-reading communication terminal 1 broadcasts a failure occurrence notification (information on disturbing waves) to the other remote meter-reading communication terminals 1. Therefore, each remote meter-reading communication terminal 1 receives the fault occurrence notification transmitted from the other remote meter-reading communication terminal 1 to thereby determine the occurrence status of illegal interference waves generated in the other remote meter-reading communication terminals 1. I can grasp it. Each remote meter-reading communication terminal 1 identifies the position of the source of the illegal jamming wave based on the situation of the illegal jamming wave in its own terminal and the status of the illegal jamming wave in the other remote metering communication terminal 1 Then, the master station 2 is notified. The master station 2 notifies the supplier of information on the source of the illegal interference wave specified by each remote meter reading communication terminal 1. Accordingly, the supplier can take measures and countermeasures against the source of the illegal interference wave based on the content notified from the master station 2.

DESCRIPTION OF SYMBOLS 1 Remote meter-reading communication terminal 10 Arithmetic processing part 11 Storage part 1b Transmission / reception part 1e RSSI part 1f Signal processing part 1g Reception success / failure determination part 1h Interference wave determination part 1i Communication failure determination part 1j Pattern storage part 1k Reception state storage part (interference wave) Time storage unit, failure time storage unit, signal strength storage unit)

Claims (5)

A communication terminal for remote meter reading that includes a transmission / reception unit for transmitting and receiving radio signals, and transmits meter reading information representing the amount of use of a supply medium supplied by a supplier in a consumer,
A pattern storage unit that stores in advance a signal generation pattern defined by the Radio Law for communications performed in the frequency band used by the transceiver unit;
An interference wave determination unit that determines whether or not the interference wave is caused by communication based on the Radio Law when an interference wave occurs,
The signal generation pattern repeats alternately a permission period in which transmission of radio signals is permitted and a prohibition period in which transmission of radio signals is prohibited, and defines each time length of the permission period and the prohibition period. Yes,
When the interference wave generation pattern received by the transmission / reception unit matches the signal generation pattern, the interference wave determination unit determines that the interference wave is due to communication based on a radio law, and the transmission / reception unit A remote meter-reading communication terminal characterized in that, when the generated interference wave generation pattern does not match the signal generation pattern, the interference wave is determined not to be communication based on the Radio Law. An interfering wave time storage unit for storing a time when the interfering wave is received;
A failure time storage unit for storing a time at which reception of the radio signal by the transceiver unit fails;
A signal strength storage unit for storing the strength of the radio signal received by the transceiver unit;
When the difference between the time at which the reception has failed and the time at which the jamming wave has been received is equal to or less than a predetermined time, and the strength of the radio signal at the time at which the reception has failed is equal to or greater than a predetermined strength, the reception failure is The communication terminal for remote meter reading according to claim 1, further comprising: a communication failure determination unit that determines that the interference wave is a cause.   3. A remote meter reading communication system comprising: a plurality of remote meter reading communication terminals according to claim 1; and a master station that communicates with the remote meter reading communication terminal.   When the remote meter reading communication terminal detects an interference wave, the remote meter reading communication terminal transmits information on the interference wave to the master station, and the master station transmits information on the jamming wave transmitted from each of the remote meter reading communication terminals. 4. The remote meter reading communication system according to claim 3, wherein a position of a source of the disturbing wave is specified based on the information.   When the remote meter-reading communication terminal detects an interference wave, the remote meter-reading communication terminal transmits information related to the interference wave to the other remote meter-reading communication terminal and receives the interference wave transmitted from the other remote meter-reading communication terminal. In this case, the position of the source of the disturbing wave is identified based on the information regarding the disturbing wave detected by the terminal and the information regarding the disturbing wave transmitted from the other remote metering communication terminal. 4. The remote meter reading communication system according to claim 3, wherein the information on the position of the source of the disturbing wave is transmitted to the master station.

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