JP2018174497A - Radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate channel change work at each installation place of a radio master unit and a radio slave unit and prevent of generation an increase in operating time and power consumption, even when the radio slave unit has an adverse of an interrupting electric wave.SOLUTION: A radio master unit 1 and radio slave units 2a-2d are initially set to 5 ch causing no interruption before starting the operation (S1). The radio master unit 1 concurrently wait for at 3-7 ch (S2). Each radio slave unit communicates with the radio master unit 1 at 5 ch when no interruption occurs at 5 ch (S3, S6, S9, S10). When interruption occurs, the radio communication system changes over the channel (S4, S7) and communicates with the radio master 1 (S5, S8).SELECTED DRAWING: Figure 6

Description

  In the present invention, in response to a call from the wireless master device, the wireless slave device transmits meter reading data such as gas and water to the wireless master device, and the wireless master device transmits the received meter reading data to the center device via the network. The present invention relates to a wireless communication system suitable for use in a meter reading data collection system.

  In recent years, a meter reading data collection system that automatically collects meter reading data such as a gas meter by a remote center device using a public line has been put into practical use. This system is installed in close proximity to each home gas meter, etc., and receives the measurement value transmitted from the wireless slave unit that transmits the measurement value (meter reading data) of the meter by specific low-power radio. And a wireless master device that transmits the measured value to the center device via a public line (see Patent Document 1).

  In such a meter reading data collection system, the wireless master device that has received a periodic meter reading request from the center device requests the wireless slave device to transmit meter reading data. In order to save power consumption of the slave unit, the wireless slave unit is intermittently driven. That is, power is supplied to the wireless communication means of the wireless slave unit for a certain period of time (for example, 1 to 500 msec) every predetermined time (for example, 1 to 60 seconds), and the presence or absence of a calling signal (transmission request for meter reading data) The intermittent drive is canceled only when the call signal is confirmed, and the meter value is measured and transmitted. Here, the presence / absence of a paging signal is checked by first determining the presence / absence of a radio carrier in the channel being used, and if there is, the radio carrier is demodulated and whether an ID addressed to itself is included. The process which determines is performed. If the calling signal from the wireless master unit is not confirmed within a certain time, the power supply to the wireless communication means is stopped until the next predetermined time comes. This makes it possible to extend the battery life in the wireless slave unit.

  Further, in such meter reading data collection system, specific low-power radio communication between the radio master unit and the radio slave unit constituting the radio communication system is performed from a plurality of channels provided within a predetermined frequency band. One channel is selected and operated. Further, when a plurality of wireless communication systems are adjacent to each other, the channel used for each wireless communication system is made different so as not to cause interference.

  Further, in such a wireless communication system, when a communication failure occurs due to the influence of noise or an interference wave from an adjacent wireless communication system, switching to another channel that is not affected is performed. In addition, in order to save the trouble of switching work, multi-channel operation is also performed in which a plurality of setting channels are automatically switched and used from the start of operation.

Japanese Patent No. 4026069

  The above-described channel switching (hereinafter sometimes referred to as “ch”) is a low-power wireless communication system, so that the terminal installation range is narrow (for example, a radius of 100 to 200 m from the wireless master unit). The movement distance of the worker at the time is short. In addition, since the installation range is narrow, all terminals often receive the same interference wave, and interference can be avoided by simple channel switching (for example, changing 5ch to 8ch) for all terminals.

  However, in a high-power wireless communication system, since the installation distance between terminals is about several kilometers away, not only the problem of long movement distance of workers but also noise and jamming waves affecting each terminal However, there is a problem that the influence cannot be avoided by simple channel switching for all terminals.

  In addition, since the multi-channel operation described above always operates in multi-channel, even when there is no influence of noise or interference from other wireless communication systems, communication operation in multiple channels (for each channel switching) Therefore, there is a problem that the operation time and power consumption are increased as compared with the operation on a single channel.

  The present invention has been made in order to solve such a problem, and its purpose is to provide a wireless communication system having a wireless master device and a wireless slave device, even if the wireless slave device is affected by jamming radio waves. It is to make it unnecessary to change the channel at each installation location of the wireless master device and the wireless slave device, and to prevent an increase in operation time and power consumption.

  A wireless communication system according to the present invention is a wireless communication system having a wireless master device and a wireless slave device, wherein the wireless master device includes a receiving means capable of simultaneously receiving radio waves of a plurality of continuous channels, Transmission means capable of transmitting a channel radio wave, and means for selecting a single channel of a radio wave to be transmitted to the wireless slave unit based on a frequency of the radio wave transmitted from the wireless slave unit, the radio The slave unit transmits a single channel radio wave selected from the plurality of channels to the wireless master unit, and when a jamming radio wave is detected in the selected single channel, the transmission unit Switching means for switching the radio wave channel to another channel.

  According to the present invention, in a wireless communication system having a wireless master device and a wireless slave device, even if the wireless slave device is affected by jamming radio waves, the channel change work at the respective installation locations of the wireless master device and the wireless slave device And an increase in operating time and power consumption can be prevented.

It is a figure which shows the structure of the radio | wireless communications system which concerns on embodiment of this invention. It is a block diagram which shows the structure of a wireless main | base station. It is a block diagram which shows the structure of a radio | wireless subunit | mobile_unit. It is a flowchart which shows operation | movement of a wireless main | base station. It is a flowchart which shows operation | movement of a radio | wireless subunit | mobile_unit. It is a sequence diagram which shows operation | movement of a radio | wireless communications system.

Embodiments of the present invention will be described below with reference to the drawings.
<Configuration of wireless communication system>
FIG. 1 is a diagram showing a configuration of a wireless communication system according to an embodiment of the present invention.
As illustrated, the wireless communication system includes a wireless master device 1 and a plurality (four in this case) of wireless slave devices 2a to 2d. The wireless master device 1 and the wireless slave devices 2 a to 2 d communicate using the specific low power wireless device 3. The wireless master device 1 is connected to the center apparatus via a public line such as a cellular phone line (not shown), and a gas meter or the like is connected to the wireless slave devices 2a to 2d. However, since these are not directly related to the present invention, the description is omitted. In the following description, when the wireless slave devices 2a to 2d are not distinguished, the wireless slave device 2 is assumed.

<Configuration of wireless base unit>
FIG. 2 is a block diagram showing a configuration of the wireless master device 1.
The wireless master device 1 includes a control unit 11 that controls the entire wireless master device, and a transmission / reception unit 12, a storage unit 13, a display unit 14, and an operation input unit 15 that are connected to the control unit 11, respectively. An antenna 16 is connected to the transmission / reception unit 12.

  The control unit 11 is composed of, for example, a microprocessor and its peripheral circuits, and performs control of the entire wireless master unit, arithmetic processing, and the like. Here, the slave unit channel determination unit 11a and the transmission channel selection unit 11b are illustrated as units realized by the control unit 11 processing programs and data stored in the storage unit 13. Details of these means will be described later.

  The transmission / reception unit 12 transmits / receives data to / from the wireless slave unit 2 using the specific low power radio by the antenna 16. Here, transmission is performed with a high output (for example, 250 mW) in the 920 MHz band. In addition, in the standard of 920 MHz (ARIB STD-T108), it is allowed to use a maximum of five unit channels having continuous frequencies at the same time. Therefore, in this embodiment, five unit channels (here, (X− 2) to (X + 2) ch).

  In addition, the transmission / reception unit 12 is configured to detect the frequency of the radio wave received from the wireless slave unit 2 received by the antenna 16 and supply it to the slave unit channel determination means 11a in the control unit 11 as frequency data. The handset channel determination means 11a determines which of the above five unit channels the channel used by the wireless handset 2 is based on the input frequency data. As will be described in detail later, the initial setting value of the channel used by the wireless slave unit 2 is Xch at the center of (X-2) to (X + 2) ch, but is switched when a jamming radio wave is detected on Xch. The determination result of the slave unit channel is stored in a slave unit channel management table 13b in the storage unit 13 to be described later, and is used by the transmission channel selection unit 11b that selects the radio wave channel transmitted to the wireless slave unit 2 by the transmission / reception unit 12. Is done.

  The storage unit 13 includes a nonvolatile memory such as a ROM, a rewritable nonvolatile memory such as a flash memory, and a volatile memory such as a RAM. The ROM stores a control program necessary for operating the wireless master device 1. The RAM stores each program being executed by the control unit 11 and information necessary for executing the programs. Various setting data and the like are stored in the rewritable nonvolatile memory.

  Here, the parent device channel management table 13a and the child device channel management table 13b are shown. The five unit channels described above are registered in advance in the parent device channel management table 13a. In addition, the slave channel management table 13b stores Xch as an initial set value, and is then updated by the determination result of the slave channel determination unit 11a. Here, the unit channels of the slave units 2a, 2b, 2c, and 2d represent the states of Xch, Xch, (X + 1) ch, and (X-1) ch, respectively.

  The display unit 14 is configured by an LED or the like, and is a user I / F that displays an operation state or the like of the wireless master device 1. The operation input unit 15 includes a button, a switch, and the like, and is a user I / F for inputting predetermined settings for the wireless master device 1.

<Configuration of wireless slave unit>
FIG. 3 is a block diagram illustrating a configuration of the wireless slave device 2.
The wireless slave unit 2 includes a control unit 21 that controls the entire wireless slave unit, and a transmission / reception unit 22, a storage unit 23, a display unit 24, and an operation input unit 25, each of which is connected to the control unit 21. An antenna 26 is connected to the transmission / reception unit 22.

  The control unit 21 includes, for example, a microprocessor and its peripheral circuits, and performs control of the entire wireless master unit, arithmetic processing, and the like. Here, the interference detection means 21a and the channel selection means 21b are illustrated as means realized by the control unit 21 processing the programs and data stored in the storage unit 23. Details of these means will be described later.

  The transmission / reception unit 22 performs data transmission / reception to / from the radio base unit 1 using the specific low power radio from the antenna 26. Here, transmission is performed with a high output (for example, 250 mW) in the 920 MHz band. In addition, one of five unit channels having continuous frequencies (here, (X-2) to (X + 2) ch) is selected and used.

  The transmission / reception unit 22 is configured to supply the jamming radio wave received by the antenna 26 to the jamming detection means 21 a in the control unit 21. The detection result of the interference detection unit 21a is used by a channel selection unit 21b that selects a radio wave channel used by the transmission / reception unit 22 for transmission / reception.

  The storage unit 23 includes a nonvolatile memory such as a ROM, a rewritable nonvolatile memory such as a flash memory, and a volatile memory such as a RAM. The ROM stores a control program necessary for operating the wireless slave unit 2. The RAM stores each program being executed by the control unit 21 and information necessary for the execution thereof. Various setting data and the like are stored in the rewritable nonvolatile memory.

  Here, the usable channel setting table 23a and the usable channel setting table 23b are illustrated. In the usable channel setting table 23a, (X-2) to (X + 2) ch that can be used for transmission / reception in the transmission / reception unit 22 are set in advance, and the channel being used is stored in the used channel setting table 23b. The The initial setting value of this use channel setting table is Xch, and is then updated to the channel selected by the channel selection means 21b. Here, Xch is being used.

  The display unit 24 is configured by an LED or the like, and is a user I / F that displays an operation state or the like of the wireless master device 1. The operation input unit 25 includes a button, a switch, and the like, and is a user I / F for inputting predetermined settings for the wireless master device 1.

<Operation of wireless master unit and wireless slave unit>
The operation of the wireless communication system having the above configuration will be described in the order of the operation flow of the wireless master device 1 and the wireless slave device 2.

<Operation of wireless base unit>
FIG. 4 is a flowchart showing the operation of the wireless master device 1.
First, the initial setting is set to the X channel (for example, 5 channels), the slave unit channel management table 13b is created (step ST1), and the standby state is set (step ST2).

  At the time of reception from the wireless slave unit 2, the transmission / reception unit 12 simultaneously receives five unit channels consisting of (X-2) to (X + 2) ch (step ST3), and the slave unit channel determination unit 11a receives the center frequency of the received radio wave. Thus, the unit channel of the wireless slave unit 2 is specified (step ST4).

  And it communicates with the radio | wireless subunit | mobile_unit 2 by the specified unit channel (step ST5), and if communication is complete | finished (step ST6), it will be judged whether a communication channel is the X channel initialized (step ST7).

  When the communication channel is the X channel (step ST7: Yes), the process proceeds to the standby state as it is, and when it is not the X channel (step ST7: No), the handset channel management table 13b is updated (step ST8). ), Transition to the standby state.

  At the time of transmission to the wireless slave unit 2, the unit channel of the partner slave unit is read from the slave unit channel management table 13b (step ST9), the unit channel is selected by the transmission channel selection unit 11b, and communication with the wireless slave unit 2 is performed. (Step ST10), the communication is terminated (Step ST11).

<Operation of wireless slave unit>
FIG. 5 is a flowchart showing the operation of the wireless slave device 2.
First, the initial setting of the use channel setting table 23b is set to X channel (for example, 5 channels) (step ST21), and a standby state is set (step ST22).

  When receiving from the wireless master device 1, it is received on the current setting channel (step ST23). And it communicates by the present setting channel (step ST24), and communication is complete | finished (step ST25).

  At the time of transmission to the wireless master device 1, a carrier check is performed on the current set channel (step ST26), and it is determined whether noise is detected (step ST27). If noise is not detected (step ST27: No), communication is performed using the current setting channel (step ST28), and communication is terminated (step ST29). When noise is detected (step ST27: Yes), the set channel is changed (step ST30), and the process proceeds to step ST26.

<Operation of wireless communication system>
FIG. 6 is a sequence diagram showing the operation of the wireless communication system. Here, a case will be described in which five consecutive unit channels are 3 to 7 channels and the initial setting channel is 5 channels.

  There is no interference such as noise in the five channels between the wireless master device 1 and the wireless slave devices 2a to 2d, and the initial setting of the single channel of the slave devices 2a to 2d is started as five channels (sequence S1). The handset channel management table 13b at this time is shown in Table 1 below.

  The wireless master device 1 simultaneously waits for 3 to 7 channels (sequence S2), and performs communication with the wireless slave device 2a using 5 channels (sequence S3). After that, since the wireless slave unit 2a detects interference in 5 channels and switches to 6 channels (sequence S4), the wireless master device 1 and the wireless slave device 2a communicate with each other in 6 channels (sequence S5). The handset channel management table 13b at this time is shown in Table 2 below.

  The wireless master device 1 communicates with the wireless slave device 2d using the five channels that are initially set (sequence S6). After that, the wireless slave unit 2d detects interference in 5 channels and detects interference even when switching to 6 channels, so it switches to 4 channels (sequence S7). The wireless master device 1 and the wireless slave device 2d communicate with each other through four channels (sequence S8). The handset channel management table 13b at this time is shown in Table 3 below.

  In the wireless slave devices 2b and 2c, since no interference has been detected since the initial setting, the wireless master device 1 communicates with the wireless master devices 2b and 2c through the initially set five channels (sequences S9 and S10). ).

As described above in detail, the wireless communication system according to the embodiment of the present invention has the following features (1) to (3).
(1) For the 920 MHz band, ARIB STD-T108 applies the rule that up to 5 unit channels can be used simultaneously only during the reception operation of the wireless master unit 1 and operates up to 5 unit channels simultaneously. . As a result, the wireless slave unit 2 selects and transmits one channel that is not affected by noise or other systems among the set maximum five simultaneous use channels, and the wireless master unit 1 selects the simultaneous use channel. Of these, the channel that has been received is identified using the frequency detection function, and is returned on that channel, so that wireless communication between the parent and the child can be established. That is, even if all the terminals in the communication system do not use the same channel, communication can be performed between the parent and the child regardless of which channel is used as long as it is within a preset maximum of five channels.
(2) It is no longer necessary to search for the same channel that can be used in common for all terminals that are not affected by noise or interference from other systems. Get better. For this reason, it is not necessary to suspend the operation for communication recovery.
(3) By performing reception using the simultaneous channels, a reception operation for a maximum of 5 channels can be performed in a reception operation time for one channel, and power consumption can be suppressed as compared with the conventional multi-channel method.

DESCRIPTION OF SYMBOLS 1 ... Radio | wireless main | base station, 2, 2a-2d ... Radio | wireless subunit | mobile_unit, 12, 22 ... Transmission / reception part, 11a ... Slave unit channel determination means, 11b ... Transmission channel selection means, 21a ... Interference detection means, 21b ... Channel selection means.

Claims (3)

A wireless communication system having a wireless master and a wireless slave,
The wireless master unit includes a receiving unit capable of simultaneously receiving radio waves of a plurality of continuous channels, a transmitting unit capable of transmitting radio waves of the plurality of channels, and a single channel of radio waves transmitted to the wireless slave unit. Selecting means for selecting based on the frequency of the radio wave transmitted from the wireless slave unit,
The wireless slave unit is configured to transmit a radio wave of a single channel selected from the plurality of channels to the radio base unit, and when a jamming radio wave is detected in the selected single channel, Switching means for switching the radio wave channel of the transmission means to another channel,
Wireless communication system. The communication system according to claim 1,
A communication system, wherein the plurality of consecutive central channels are set as an initial setting channel of the single channel. The communication system according to claim 2,
The switching means is a communication system for switching to an adjacent channel when interference is detected in an initially set channel.

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