JP5588333B2 - Wireless communication device - Google Patents

Description

  The present invention relates to a wireless communication apparatus that is used in a wireless communication system or the like and can determine the occurrence of erroneous carrier sense due to noise.

  As a wireless communication device constituting a wireless communication system, typically, a wireless master device that collects data, a wireless slave device that transmits data to the wireless master device, and, if necessary, a wireless master device and a wireless slave device, And a wireless repeater that relays the communication. Among these, the wireless slave unit or the wireless relay unit can perform wireless communication using a specific channel and wireless communication using a sub-channel.

  In such a wireless communication device, a technique that can automatically switch to a sub-channel while using a main channel has been proposed. For example, in Patent Document 1, when carrier sense is performed on the main channel and the strength of the reception signal having the channel frequency of the main channel is equal to or lower than a threshold, it is determined that the main channel is usable, A wireless communication device having a configuration in which when the strength exceeds a threshold, the main channel is determined to be in use and is automatically switched to the sub-channel is disclosed.

JP 2009-290799 A

  However, in the technique disclosed in Patent Document 1, appropriate carrier sense cannot be performed in an environment in which noise is generated across the main channel and subchannel. In this case, for example, carrier sense is frequently repeated in order to check the communication status. Among the wireless communication devices, wireless slave devices and the like have a configuration having an internal battery as a power supply unit, and if such a wireless communication device, the internal battery is consumed due to frequent carrier sense, There is a risk that the communicable state may be shortened (lifetime shortened).

  Here, if it is possible to confirm in advance that noise over the main channel and the sub-channel exists, the installation location of the wireless communication device can be changed so that appropriate carrier sense is possible. However, if the presence of the noise is not noticed, the presence of the noise may be noticed after the installation of the wireless communication apparatus, after the internal battery is exhausted and the communication is disabled. In this case, it is necessary to replace or re-install the wireless communication device, which causes complicated maintenance and increased costs.

  The present invention has been made to solve such a problem, and by making it possible to determine the occurrence of erroneous carrier sense due to noise with a simple configuration, it suppresses unnecessary consumption of the internal battery and has a long service life. It is an object of the present invention to provide a wireless communication device that can be realized.

  In order to solve the above problems, a wireless communication apparatus according to the present invention includes a transmission / reception unit that performs carrier sense and wireless communication, a carrier sense counting unit that counts the number of times of carrier sense performed by the transmission / reception unit, And an erroneous carrier sense determination unit that determines that an erroneous carrier sense has occurred if the number of times counted by the carrier sense counting unit exceeds a preset determination reference number.

  In the above configuration, the carrier sense counting unit may be configured to count the number of times of starting demodulation of the received signal, or the carrier sense counting unit starts demodulating the received signal, and the received signal is automatically detected. It may be configured to count the number of times it is determined that the signal is not addressed to the machine.

  Further, the configuration further includes a control unit and a display unit, and the control unit displays warning information on the display unit when the occurrence of erroneous carrier sense is determined by the erroneous carrier sense determination unit. It may be.

  The configuration further includes a switch unit, and the control unit causes the transmission / reception unit to perform carrier sense and causes the erroneous carrier sense determination unit to perform determination when the switch unit is operated. It may be configured.

  In the configuration, the power supply unit further includes a built-in battery, and the control unit receives at least the transmission / reception unit from the power supply unit when occurrence of erroneous carrier sense is determined by the erroneous carrier sense determination unit. It may be configured to cut off the power supply to.

  In addition, the wireless communication device according to the present invention relays communication between a wireless slave that acquires and transmits data to a wireless master that collects data, or between the wireless master and the wireless slave. A wireless repeater may be used.

  As described above, the wireless communication device according to the present invention can suppress the occurrence of an erroneous carrier sense due to noise with a simple configuration, thereby suppressing unnecessary consumption of the internal battery and extending the life. There is an effect that it is possible.

(A) is a schematic diagram which shows an example of the radio | wireless communications system containing the radio | wireless communication apparatus which concerns on embodiment of this invention, (b) is a radio | wireless subunit | mobile_unit or radio | wireless relay of the radio | wireless communications system shown to (a). It is a flowchart which shows an example of the control of the carrier sense performed by a machine. It is a block diagram which shows an example of a structure of the radio | wireless communication apparatus corresponding to the radio | wireless subunit | mobile_unit or radio | wireless relay machine of the radio | wireless communications system shown in FIG. 3 is a flowchart illustrating an example of control for determining erroneous carrier sense performed by the wireless communication apparatus illustrated in FIG. 2. 7 is a flowchart illustrating another example of control for determining erroneous carrier sense performed in the wireless communication apparatus illustrated in FIG. 2.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference symbols throughout the drawings, and redundant description thereof is omitted.

[Wireless communication system and carrier sense]
A wireless communication system using a wireless communication apparatus according to an embodiment of the present invention and carrier sense performed by a wireless slave unit or the like constituting the system will be specifically described with reference to FIGS. explain.

  As shown in FIG. 1A, the wireless communication system according to the present embodiment includes a wireless master device 101, a wireless relay device 102, and a wireless slave device 103. The wireless master device 101 collects data and outputs the collected data to a host computer (not shown). The wireless relay device 102 relays communication between the wireless master device 101 and the wireless slave device 103. The wireless slave device 103 acquires data and transmits it to the wireless master device 101. In the present embodiment, the wireless slave device 103 is connected to a gas meter (not shown) in FIG. 1, acquires the gas flow rate in the gas pipe, and transmits it to the wireless master device 101. Note that the wireless repeater 102 may not be included in the system depending on the use conditions of the wireless communication system.

  In the wireless communication system configured as described above, the wireless slave device 103 performs carrier sense between the wireless master device 101 and the wireless relay device 102. The wireless relay device 102 performs carrier sense with the wireless master device 101. This carrier sense control will be described in detail. As shown in FIG. 1 (b), a signal equal to or higher than a threshold value is transmitted in a communication channel set in advance with the wireless master device 101 (or the wireless relay device 102). It is determined whether or not it has been received (step S101). If the received signal is less than the threshold value (NO in step S101), the signal reception determination is repeated.

  On the other hand, if the received signal is equal to or greater than the threshold (YES in step S101), demodulation of the received signal is started (step S102). Then, it is determined whether or not the demodulated signal is a signal addressed to the own device (step S103). If it is not addressed to itself (NO in step S103), the demodulation is stopped (step S104), and the signal reception determination is repeated. If it is addressed to the own device (YES in step S103), the demodulated data is received (step S105), and the carrier sense control is terminated.

[Configuration of wireless communication device]
Next, the configuration of the main part of the wireless communication apparatus according to the present embodiment, that is, the wireless slave device 103 or the wireless relay device 102 that performs the carrier sense will be specifically described with reference to FIG. 2 is the wireless slave device 103 connected to the gas meter 20, the wireless relay device 102 has the same configuration.

  As shown in FIG. 2, the wireless communication device (wireless handset 103) according to the present embodiment includes a transmission / reception unit 11, a control unit 12, a carrier sense counting unit 121, an erroneous carrier sense determination unit 122, an input / output unit 123, A storage unit 124, a display unit 13, a switch unit 14, a power supply unit 15 and the like are provided.

  The transmission / reception unit 11 performs wireless communication with other wireless communication devices such as the wireless master device 101 and the wireless relay device 102. This wireless communication includes the carrier sense described above. The control unit 12 controls the entire wireless communication apparatus, and also controls wireless communication and carrier sense of the transmission / reception unit 11. Therefore, the carrier sense control shown in the flowchart of FIG.

  The carrier sense counting unit 121 counts the number of carrier senses performed by the transmission / reception unit 11. The number of times of carrier sense may be the number of times of starting demodulation of the received signal (number of times of step S102 in FIG. 1B), or demodulation of the received signal is started, and the received signal is not a signal addressed to the own device. This may be the number of times determined (the number of times determined as NO in step S103). The former is referred to as “demodulation start number”, and the latter is referred to as “error carrier sense number”. The erroneous carrier sense determination unit 122 determines that an erroneous carrier sense has occurred if the number of times counted by the carrier sense counting unit 121 exceeds a preset determination reference number.

  The input / output unit 123 is connected to the gas meter 20 or another external device, and inputs / outputs data to / from the external device. In the present embodiment, the gas flow rate value measured by the gas meter 20 is input, or various command signals are output to the gas meter 20. The storage unit 124 can store various data, and is configured to be able to read or write data via the control unit 12. For example, the ID data of the wireless master device 101 or the wireless relay device 102, the ID data of the own device, the threshold value of the received signal for carrier sense determination, the number of determination criteria, various programs, etc. are stored in a readable manner. The gas flow rate value acquired from 20 can be stored.

  The display unit 13 is a low power consumption display device such as an LED lamp or a segment type small liquid crystal panel, and can display various information under the control of the control unit 12. The switch unit 14 includes a switch for turning on / off the power of the wireless communication device, a switch for turning on / off a specific function of the wireless communication device, and the like in the present embodiment. This switch is used both for power ON / OFF and erroneous carrier sense determination ON / OFF. The power supply unit 15 is composed of a built-in battery.

  The specific configuration of the wireless communication apparatus is not limited to the configuration example illustrated in FIG. 2 and the above-described configuration example, and various types of configurations known in the field can be suitably used. Further, a notification unit other than the display unit 13 may be provided, and the switch unit 14 may not be provided.

[Error carrier sense judgment]
Next, the erroneous carrier sense determination performed in the above-described wireless communication apparatus will be specifically described with reference to FIGS. First, the carrier sense determination control shown in FIG. 3 will be described. This control is a control for counting the number of times of demodulation start as the number of carrier senses.

  First, the control unit 12 determines the start of execution of carrier sense control shown in FIG. 1B (step S201). If carrier sense control is not started (NO in step S201), this determination is repeated. If the carrier sense control is started (YES in step S201), the carrier sense counter 121 counts (counts) the number of times of demodulation start (number of times of start of demodulation of the received signal) (step S202).

  Next, the control unit 12 determines whether or not the erroneous carrier sense determination unit 122 has the demodulation start count equal to or greater than the predetermined count, that is, the determination reference count (step S203). If it is less than the predetermined number (NO in step S203), the process returns to the determination of the start of carrier sense control (step S201). On the other hand, if it is equal to or greater than the predetermined number of times (YES in step S203), it is determined that an erroneous carrier sense has occurred.

  If an erroneous carrier sense has occurred, the control unit 12 informs the display unit 13 of an installation impossible display as warning information, for example (step S204). This installation impossible display is an error display indicating that the place where the wireless slave unit 103 is temporarily installed is inappropriate for installation, in other words, there is noise exceeding the receivable level at the temporary installation place. It is a display which shows that it exists. For example, if the display unit 13 is an LED lamp, it is normally displayed in green, and is displayed in red when the display is impossible. In addition, the display in the display part 13 should just be a display of warning information, and is not limited to an installation impossible display.

  The control of erroneous carrier sense determination may be terminated by displaying warning information, but preferably, as shown in FIG. 3, the control unit 12 shifts to a sleep mode after a predetermined time has elapsed (step S205). The control may be terminated after performing the above. The sleep mode here may be an operation mode that minimizes power consumption of the power supply unit 15, and at least power supply from the power supply unit 15 to the transmission / reception unit 11 may be cut off. In the wireless communication apparatus, power consumption due to the operation of the transmission / reception unit 11 normally occupies the largest ratio. Therefore, if at least the operation of the transmission / reception unit 11 is stopped, the power consumption of the power supply unit 15 can be suppressed. Of course, you may stop operation | movement of another component.

  Next, the carrier sense determination control shown in FIG. 4 will be described. This control is control when counting the number of erroneous carrier senses as the number of carrier senses.

  First, the control unit 12 determines the start of execution of the carrier sense control shown in FIG. 1B (step S301). If carrier sense control is not started (NO in step S301), this determination is repeated. If carrier sense control is started (YES in step S301), it is determined whether or not it is erroneous carrier sense, that is, whether or not the demodulated received signal is a signal addressed to the own device (step S302). If it is determined that there is an erroneous carrier sense, the carrier sense counting unit 121 counts (counts) the number of times (step S303).

  Next, the control unit 12 causes the erroneous carrier sense determination unit 122 to determine whether or not the number of erroneous carrier senses is equal to or greater than a predetermined number, that is, a determination reference number (step S304). If it is less than the predetermined number (NO in step S304), the process returns to the determination of the start of carrier sense control (step S301). On the other hand, if it is equal to or greater than the predetermined number of times (YES in step S304), it is determined that an erroneous carrier sense has occurred and, as described above, the display unit 13 is informed of an installation impossible display as warning information (step (S305) After the elapse of a predetermined time, the control is terminated after shifting to the sleep mode (step S306).

  The control of the erroneous carrier sense determination in FIG. 3 or FIG. 4 described above may be performed at any timing. For example, when the switch unit 14 is operated and the wireless communication apparatus shifts from OFF to ON. It is preferable that it is configured to be performed. That is, when the switch unit 14 is operated, the control unit 12 causes the transmission / reception unit 11 to perform carrier sense, and causes the erroneous carrier sense determination unit 122 to perform erroneous carrier sense determination from the count result of the carrier sense counting unit 121. May be.

  This makes it possible to investigate the wireless communication environment (presence / absence of noise) using the installation of the wireless communication device as a trigger, and to notify whether the communication environment is good or bad at the time of installation. This avoids the waste of installing a wireless communication device in a noisy environment, and the product life of the wireless communication device is inadvertently shortened, or once installed, the wireless communication device is moved to another location. There is no need to do.

  It should be noted that the present invention is not limited to the description of the above-described embodiment, and various modifications are possible within the scope shown in the scope of the claims, and are disclosed in different embodiments and a plurality of modifications. Embodiments obtained by appropriately combining the technical means are also included in the technical scope of the present invention.

  The present invention can be widely and suitably used in the field of wireless communication devices that require carrier sense.

DESCRIPTION OF SYMBOLS 11 Transmission / reception part 12 Control part 13 Display part 14 Switch part 15 Power supply part 101 Radio | wireless parent machine 102 Radio relay machine (wireless communication apparatus)
103 wireless handset (wireless communication device)
121 Carrier sense counting unit 122 Incorrect carrier sense determination unit

Claims (6)

A transceiver for performing carrier sense and wireless communication;
A carrier sense counting unit that counts the number of carrier senses performed by the transceiver unit;
An erroneous carrier sense determination unit that determines that an erroneous carrier sense has occurred if the number of times counted by the carrier sense counting unit exceeds a preset determination reference number ;
The wireless communication apparatus, wherein the carrier sense counting unit is configured to count the number of times of starting demodulation of a received signal .   2. The carrier sense counting unit according to claim 1, wherein the carrier sense counting unit is configured to start demodulation of a received signal and to count the number of times it is determined that the received signal is not a signal addressed to the own device. Wireless communication device. A control unit and a display unit;
The wireless communication apparatus according to claim 1, wherein the control unit displays warning information on the display unit when the occurrence of erroneous carrier sense is determined by the erroneous carrier sense determination unit. A switch part,
Wherein, when the switch unit is operated, to perform the carrier sense to the transceiver unit, characterized in that it is configured to perform the determination on the erroneous carrier sense determination unit, according to claim 3 A wireless communication device according to 1. It further includes a power supply unit including a built-in battery,
The control unit is configured to cut off power supply from the power supply unit to the transmission / reception unit at least when the occurrence of erroneous carrier sense is determined by the erroneous carrier sense determination unit. The wireless communication apparatus according to claim 1.   A wireless slave device that acquires and transmits data to a wireless master device that performs data collection, or a wireless relay device that relays communication between the wireless master device and the wireless slave device, The wireless communication apparatus according to claim 1.

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