JP2008312062A - Wireless communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce variations in power consumption of a plurality of wireless units, caused by a difference in the number of times of communication in a communication system which connects wirelessly the wireless units having an intermittent receiving function in a hierarchical structure. <P>SOLUTION: The system has a hierarchical structure in which three wireless slave units 3 to 5 exist under a wireless master unit 2, two wireless slave units 4 and 5 exist under the wireless slave unit 3, and one wireless slave unit 5 exists under the wireless slave unit 4. Wireless units at higher-order positions in the hierarchical structure relay data from wireless units at lower-order positions to ones at higher-order positions. The intermittent receiving interval of wireless units at higher-order positions having an increased number of times of communication is made longer than that of wireless units at lower-order positions. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wireless communication system suitable for an automatic meter reading system for automatically collecting meter reading data such as a gas meter and a water meter, or a security system for notifying information such as a gas leak sensor and a fire sensor.

  FIG. 10 is a diagram showing a schematic configuration of such a wireless communication system. This wireless communication system includes a center device 201, a wireless master device 202, and a wireless slave device 203. The center device 201 and the wireless master device 202 perform data communication using a public communication line such as a mobile phone network. The wireless master device 202 and the wireless slave device 203 perform data communication by specific low power wireless. The wireless slave device 203 is connected to a gas meter, a water meter, a gas leak sensor, and the like.

  In the communication system configured as described above, the center device 201 periodically collects gas and water usage (meter reading data) measured by a gas meter or a water meter connected to the wireless slave device 203. The apparatus 201 periodically calls the wireless master device 202 and requests transmission of meter reading data of a meter connected to the wireless slave device 203. The wireless master device 202 calls the wireless slave device 203 according to this request and requests transmission of meter-reading data. The wireless slave device 203 transmits the meter reading data to the wireless master device 202, and the wireless master device 202 transmits the received meter reading data to the center device 201.

  The wireless slave unit 203 is driven by a battery, and in order to save power consumption, for example, an intermittent reception operation is performed in which the power of the 10 msec reception circuit is turned on every 30 seconds during standby. Here, 30 sec and 10 msec are referred to as an intermittent reception interval and an intermittent reception time, respectively. Then, the presence or absence of a call (start message) from the wireless master device 202 is checked during the intermittent reception time, that is, the time when the power of the reception circuit is turned on. If there is, the data communication is performed. Turn off the power and wait (see Patent Document 1).

  Here, as shown in FIG. 11A, a system in which the master unit 202 collects meter reading data from a plurality of wireless slave units is configured such that a plurality (three in this case) of wireless slave units 203 to 205 are directly connected to the wireless master unit 202. When configured to perform communication, the number of communications of each wireless slave unit is the same, so the power consumption is also the same.

  However, as shown in FIG. 11B, a hierarchical structure in which the wireless slave devices 204 and 205 are accommodated under the wireless slave device 203, and the wireless slave device 203 has a relay function so that the meter reading data of the wireless slave devices 204 and 205 is obtained. When configured to transmit to the wireless master device 202 via the wireless slave device 203, the number of communications of the wireless slave device 203 increases, so the power consumption increases correspondingly and the battery of the wireless slave device 203 is depleted first. Resulting in. As a result, there is a problem in that the battery replacement work for each wireless slave unit is performed at different times, which increases the number of work steps.

JP-A-8-194022

  The present invention has been made in view of such problems, and an object of the present invention is to perform communication in a wireless communication system in which a plurality of wireless communication terminal devices having an intermittent reception function are wirelessly connected so as to have a hierarchical structure. It is to reduce the variation in power consumption of the wireless communication terminal device due to the difference in the number of times.

The invention of claim 1 is a wireless communication system for wirelessly connecting a plurality of wireless communication terminal devices having an intermittent reception function so as to have a hierarchical structure, wherein the intermittent reception interval of the wireless communication terminal devices is the hierarchical structure. It has the means to set according to, It is characterized by the above-mentioned.
According to a second aspect of the present invention, in the wireless communication system according to the first aspect, the means sets the discontinuous reception interval according to the number of wireless communication terminal devices existing below the wireless communication terminal device. To do.
According to a third aspect of the present invention, in the wireless communication system according to the first aspect, the means sets the discontinuous reception interval according to the number of wireless communication terminal devices existing immediately below and immediately above the wireless communication terminal device. Features.
According to a fourth aspect of the present invention, in the wireless communication system according to any one of the first to third aspects, the wireless communication terminal device has means for setting a calling time from the wireless communication terminal device to another wireless communication terminal device according to the hierarchical structure. It is characterized by.
According to a fifth aspect of the present invention, in the wireless communication system according to any one of the first to fourth aspects, means for correcting the set intermittent reception interval and calling time according to the number of communications of the wireless communication terminal device. It is characterized by having.

(Function)
According to the invention of claim 1, by setting the intermittent reception interval of the wireless communication terminal apparatuses wirelessly connected so as to have a hierarchical structure according to the hierarchical structure, the power consumption due to the intermittent reception of the wireless communication terminal apparatus is hierarchical. It can be set according to the structure.
According to the invention of claim 2, by setting the intermittent reception interval of the wireless communication terminal devices wirelessly connected so as to have a hierarchical structure according to the number of wireless communication terminal devices existing in the lower layer, the wireless communication terminal device Depending on the number of wireless communication terminal devices existing in the lower level, power consumption due to intermittent reception of the wireless communication terminal device can be set.
According to the invention of claim 3, the intermittent reception interval of the wireless communication terminal devices wirelessly connected so as to have a hierarchical structure is set according to the number of wireless communication terminal devices existing immediately below and directly above the wireless communication terminal device. Thus, the power consumption due to intermittent reception of the wireless communication terminal device can be set according to the number of wireless communication terminal devices that directly perform data communication with the wireless communication terminal device.
According to invention of Claim 4, while setting the intermittent reception interval of the radio | wireless communication terminal device wirelessly connected so that it may have a hierarchical structure according to a hierarchical structure, the calling time with respect to another wireless communication terminal device is made into a hierarchical structure. By setting accordingly, the power consumption due to intermittent reception of the wireless communication terminal device and the power consumption due to calling to another wireless communication terminal device can be set according to the hierarchical structure.
According to the invention of claim 5, the power consumption due to the intermittent reception of the wireless communication terminal device and other wireless communication are corrected by correcting the set values of the intermittent reception interval and the calling time according to the number of communication of the wireless communication terminal device. The power consumption by calling the terminal device can be set according to the hierarchical structure and can be corrected according to the number of communications.

  According to the present invention, in a wireless communication system in which a plurality of wireless communication terminal devices having an intermittent reception function are wirelessly connected so as to have a hierarchical structure, variation in power consumption of the wireless communication terminal device due to a difference in the number of communication times is reduced. Can be reduced.

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
FIG. 1 is a diagram illustrating a configuration of a wireless communication system according to a first embodiment of this invention. This wireless communication system includes a center device 1, a wireless master device 2, and wireless slave devices 3 to 5. The center device 1 and the wireless master device 2 perform data communication through a public communication line such as a cellular phone network. The wireless master device 2 and the wireless slave device 3 perform data communication by using a specific low power radio. The wireless slave unit 3 and the wireless slave unit 4, and the wireless slave unit 4 and the wireless slave unit 5 also perform data communication by a specific low power radio. A gas meter, a water meter, a gas leak sensor, and the like are connected to the wireless slave devices 3 to 5.

  Meter reading data of the meter connected to the wireless slave unit 3 is transmitted to the center device 1 via the wireless master unit 2. Meter reading data of the meter connected to the wireless slave unit 4 is transmitted to the center device 1 via the wireless slave unit 3 and the wireless master unit 2. Meter reading data of the meter connected to the wireless slave device 5 is transmitted to the center device 1 via the wireless slave device 4, the wireless slave device 3, and the wireless master device 2. The same applies to the case where the detection data of the gas leak sensor connected to each wireless slave is notified to the center device 1.

  That is, there are three wireless slave devices 3 to 5 under the wireless master device 2, two wireless slave devices 4 and 5 are present under the wireless slave device 3, and 1 is under the wireless slave device 4. It has a hierarchical structure in which a single wireless slave unit 5 exists. Further, the wireless slave devices 3 and 4 relay data transmitted from wireless slave devices located in the lower layer of the hierarchical structure to the upper layer of the hierarchical structure, so that data from all the wireless slave devices is transmitted to the wireless parent device 2. Delivered to the center apparatus 1.

  When the communication unit of the specific low power radio of the wireless master device 2 and the wireless slave devices 3 to 5 call the communication partner, an activation message is transmitted to the communication partner. In addition, the specific low power wireless communication unit of the wireless master device 2 and the wireless slave devices 3 to 5 perform an intermittent reception operation during standby. When the intermittent reception time during the intermittent reception operation, that is, the call (start command) addressed to itself is detected at the time when the power of the reception circuit is turned on every intermittent reception interval, the data can be transmitted and received If no call addressed to itself is detected, the receiving circuit is turned off and waits.

  Here, the intermittent reception interval (intermittent reception cycle) of the wireless master device 2 and the wireless slave devices 3 to 5 is not the same, and the more wireless slave devices there are, that is, the wireless devices present in the upper layer By making it longer, the number of intermittent receptions within a certain time is reduced, and the power consumption due to the accumulation of intermittent receptions is reduced. Thus, the increase in power consumption due to the increase in the number of data communication by relay is corrected by reducing the power consumption associated with intermittent reception in the wireless devices existing in the higher layers. Details of this point will be described later.

  FIG. 2 is a block diagram showing a configuration of the wireless slave device 3 of FIG. The wireless slave device 3 is connected to a control device 11 that controls the entire wireless slave device 3, an antenna 12, a transmission / reception switching circuit (SW) 13 connected to the antenna 12, and a transmission / reception switching circuit (SW) 13. The transmission circuit 14 and the reception circuit 15, the memory 16 for storing various data and programs used when the control device 11 operates, and an interface (I / I) connected to a meter and various sensors (not shown). F) A circuit 17 is provided.

  The control device 11 includes an intermittent reception timer 18 and a start command timer 19. The intermittent reception timer 18 is a timer for setting a time (intermittent reception time) for intermittently turning on the reception circuit 15 and an interval (intermittent reception interval). The activation command timer 19 sets a time (calling time) for transmitting the activation message generated by the control device 11 from the transmission circuit 14 when the wireless slave device 3 calls the wireless slave device 4 or the wireless master device 2. It is a timer for. Data for determining the set time of these timers is stored in the memory 16.

  The transmission / reception switching circuit (SW) 13 is a circuit that switches the antenna 12 to a transmission state or a reception state under the control of the control device 11. The transmission circuit 14 includes a modulation circuit for modulating data from the control device 11, and the reception circuit 15 includes a demodulation circuit for demodulating the received data. The interface (I / F) circuit 17 reads meter reading data of the meter in response to a command from the control device 11 and sends it to the control device 11. Further, when the gas leak sensor generates detection data, the control device 11 is notified.

  The wireless slave devices 4 and 5 are configured in the same manner as the wireless slave device 3 described above. The wireless master device 2 is obtained by adding a communication circuit for performing data communication to the configuration of the wireless slave device 3 via the mobile telephone network with the center device 1. However, the power source of the wireless master device 2 may be a battery or a commercial AC power source. Further, the center device 1 is configured by a computer having a communication function with the wireless master device 2.

  In the communication system having the above configuration, the procedure for collecting meter reading data of the meters connected to the wireless slave devices 3 to 5 by the center device 1 is described with reference to the sequence diagram shown in FIG. 3 and the timing diagram shown in FIG. While explaining.

  As shown in FIG. 3, the center apparatus 1 instructs the wireless master device 2 to collect meter reading data of the wireless slave devices 3 to 5 (step S1). When receiving the command, the wireless master device 2 transmits an activation command to the wireless slave device 3 (step S2). The reception circuit 15 of the wireless slave device 3 is performing an intermittent reception operation at the intermittent reception interval and intermittent reception time set by the intermittent reception timer 18, and demodulates the received signal and sends it to the control device 11. When the control device 11 detects the activation command addressed to the wireless slave unit 3 from the demodulated signal, the control device 11 controls the transmission circuit 14 and the reception circuit 15 to shift from the intermittent reception operation state to the state capable of data communication, and to respond to the activation response. It is created and transmitted from the transmission circuit 14 to the wireless master device 2 (step S3).

  Here, the transmission time (calling time) of the activation command to the wireless slave device 3 by the wireless master device 2 and the intermittent reception interval of the wireless slave device 3 are the intervals (4a) of the intermittent reception P2 as shown in FIGS. ) Is longer than the transmission time (4a + α) of the activation command P1. Accordingly, the wireless slave device 3 is activated by the first activation command.

  The wireless master device 2 that has received the activation response transmits a meter reading command of the wireless slave device 5 to the wireless slave device 3 (step S4). The wireless slave device 3 that has received this meter-reading command transmits an activation command to the wireless slave device 4 (step S5). The wireless slave device 4 is in the intermittent reception operation. When this activation command is detected, the wireless slave device 4 shifts from the intermittent reception operation state to a state where data communication is possible, and transmits an activation response to the wireless slave device 3 (step S6).

  Here, the transmission time (calling time) of the activation command to the wireless slave device 4 by the wireless slave device 3 and the intermittent reception interval of the wireless slave device 4 are the intervals (3a) of the intermittent reception P4 as shown in FIGS. 4C and D, respectively. ) Is longer than the transmission time (3a + α) of the start command P3. Accordingly, the wireless slave device 4 is activated by the first activation command.

  The wireless slave device 3 that has received the activation response transmits a meter reading command of the wireless slave device 5 to the wireless slave device 4 (step S7). The wireless slave device 4 that has received this meter-reading command transmits an activation command to the wireless slave device 5 (step S8). The wireless slave device 5 is performing an intermittent reception operation. When this activation command is detected, the wireless slave device 5 shifts from the intermittent reception operation state to a state where data communication is possible, and transmits an activation response to the wireless slave device 4 (step S9).

  Here, the transmission time (calling time) of the activation command to the wireless slave device 5 by the wireless slave device 4 and the intermittent reception interval of the wireless slave device 5 are the intervals (2a) of the intermittent reception P6 as shown in FIGS. ) Is longer than the transmission time (2a + α) of the activation command P5. Accordingly, the wireless slave device 5 is activated by the first activation command.

  The wireless slave device 4 that has received the activation response transmits a meter reading command of the wireless slave device 5 to the wireless slave device 5 (step S10). The wireless slave device 5 that has received the meter reading command transmits meter reading data of the meter connected to the wireless slave device 4 to the wireless slave device 4 (step S11). The wireless slave device 4 that has received the meter reading data transmits an acknowledgment response (ACK) to the wireless slave device 5 (procedure S12) and transmits the meter reading data of the wireless slave device 5 to the wireless slave device 3 (procedure S13). .

  The wireless handset 5 that has received the acknowledgment (ACK) returns to the intermittent reception operation state. The wireless slave device 3 that has received the meter reading data of the wireless slave device 5 transmits an acknowledgment response (ACK) to the wireless slave device 4 (step S14), and transmits the meter reading data of the wireless slave device 5 to the wireless master device 2. (Procedure S15).

  The wireless handset 4 that has received the acknowledgment (ACK) returns to the intermittent reception operation state. The wireless master device 2 that has received the meter reading data of the wireless slave device 5 transmits an acknowledgment response (ACK) to the wireless slave device 3 (step S16), and stores the meter reading data of the wireless slave device 5 in a built-in memory.

  The wireless handset 3 that has received the acknowledgment (ACK) returns to the intermittent reception operation state. The wireless master device 2 that has stored the meter reading data of the wireless slave device 5 then transmits an activation command to the wireless slave device 3 in order to acquire the meter reading data of the wireless slave device 4 (step S17). Thereafter, the meter reading data of the wireless slave device 4 is delivered to the wireless master device 2 by the same procedure (procedure S18 to S25) as when the meter reading data of the wireless slave device 5 is acquired.

  By repeating the above procedure, when the meter reading data of all the wireless slave devices 3 to 5 are delivered to the wireless master device 2, the wireless master device 2 collects the meter reading data of all the wireless slave devices 3 to 5 in the center device. Send to 1. Note that the wireless master device 2 may transmit the meter reading data of the wireless slave devices 3 to 5 individually, rather than collectively.

  Thus, when transmitting the meter reading data of the wireless slave devices 3 to 5 to the wireless master device 2, the wireless slave device 5 existing at the lowest level of the hierarchical structure only transmits its own meter reading data once. On the other hand, the wireless slave unit 4 transmits its own meter reading data and transmits the meter reading data of the wireless slave unit 5 in total, and the wireless slave unit 3 transmits its own meter reading data. The meter reading data is transferred and the meter reading data of the wireless slave unit 5 is transmitted three times in total.

  In other words, since the wireless slave units that are higher in the hierarchical structure and the number of times of meter reading data transmission increase, the power consumption associated with the transmission of meter reading data increases. Therefore, the battery is consumed in the order of the wireless slave units 3, 4, and 5 in this state. Therefore, in the present embodiment, as shown in FIG. 4, by shortening the intermittent reception interval in the order of the wireless slave devices 3, 4, and 5, the power consumption within a certain time due to the accumulation of intermittent reception is reduced. It is made to become large in order of 4,5. That is, by providing a difference in power consumption due to the accumulation of intermittent reception, variations in power consumption due to a difference in the number of times meter reading data is transmitted are reduced. As can be seen from FIG. 4, the transmission time (calling time) of the start command increases the variation in power consumption due to the difference in the number of times the meter reading data is transmitted, but the number of start commands is intermittent reception. Since it is far less than the number of times, it can be ignored.

  Next, a procedure for reporting the detection information (alarm) of the gas leak sensor connected to the wireless slave device 5 to the center device 1 will be described with reference to the sequence diagram shown in FIG. 5 and the timing diagram shown in FIG. .

  As shown in FIG. 5, in the wireless master device 2 and the wireless slave devices 3 to 5, each reception circuit 15 is performing an intermittent reception operation at the intermittent reception interval and intermittent reception time set by the intermittent reception timer 18. When the gas leak sensor connected to the wireless slave unit 5 detects gas, the gas leak sensor transmits an activation command to the wireless slave unit 5 (step S31). The wireless slave device 5 is activated by this activation command, shifts to a state where data communication is possible, and transmits an activation command to the wireless slave device 4 (step S32). The wireless slave device 4 is in the intermittent reception operation. When this activation command is detected, the wireless slave device 4 shifts from the intermittent reception operation state to a state where data communication is possible, and transmits an activation response to the wireless slave device 5 (step S33).

  Here, the transmission time (calling time) of the activation command to the wireless slave device 4 by the wireless slave device 5 and the intermittent reception interval of the wireless slave device 4 are the intervals (3a) of the intermittent reception P8 as shown in FIGS. 6A and 6B, respectively. ) Is longer than the transmission time (3a + α) of the activation command P7. Accordingly, the wireless slave device 4 is activated by the first activation command.

  The wireless slave device 5 that has received the activation response transmits an alarm from the wireless slave device 5 to the wireless slave device 4 (step S34). The wireless slave device 4 that has received this warning transmits an acknowledgment response (ACK) to the wireless slave device 5 (procedure S35) and transmits an activation command to the wireless slave device 3 (procedure S36). The wireless handset 5 that has received the acknowledgment (ACK) returns to the intermittent reception operation state.

  The wireless slave unit 3 is in the intermittent reception operation. When the activation instruction is detected, the wireless slave unit 3 shifts from the intermittent reception operation state to a state where data communication is possible, and transmits an activation response to the wireless slave unit 4 (step S37).

  Here, the transmission time (calling time) of the start command to the wireless slave device 3 by the wireless slave device 4 and the intermittent reception interval of the wireless slave device 3 are the intervals (4a) of the intermittent reception P10 as shown in FIGS. 6C and D, respectively. ) Is longer than the transmission time (4a + α) of the start command P9. Accordingly, the wireless slave device 3 is activated by the first activation command.

  The wireless slave device 4 that has received the activation response transmits an alarm from the wireless slave device 5 to the wireless slave device 3 (step S38). The wireless slave device 3 that has received this alarm transmits an acknowledgment response (ACK) to the wireless slave device 4 (step S39) and transmits an activation command to the wireless master device 2 (procedure S40). The wireless handset 4 that has received the acknowledgment (ACK) returns to the intermittent reception operation state.

  The wireless master device 2 is in the intermittent reception operation. When the activation command is detected, the wireless master device 2 shifts from the intermittent reception operation state to a state where data communication is possible, and transmits an activation response to the wireless slave device 3 (step S41).

  Here, the transmission time (calling time) of the start command to the wireless master device 2 by the wireless slave device 3 and the intermittent reception interval of the wireless master device 2 are the intervals (5a) of the intermittent reception P12 as shown in FIGS. ) Is longer than the transmission time (5a + α) of the start command P11. Accordingly, the wireless master device 2 is activated by the first activation command.

  The wireless slave device 3 that has received the activation response transmits an alarm from the wireless slave device 5 to the wireless master device 2 (step S42). The wireless master device 2 that has received this warning transmits an acknowledgment response (ACK) to the wireless slave device 3 (step S43) and transmits an alarm for the wireless slave device 5 to the center device 1 (procedure S44). Send a start command. The wireless handset 4 that has received the acknowledgment (ACK) returns to the intermittent reception operation state.

  The center device 1 that has received the alarm from the wireless slave device 5 transmits an acknowledgment response (ACK) to the wireless master device 2 (step S45). The wireless master device 2 that has received the acknowledgment (ACK) returns to the intermittent reception operation state.

  As described above, when the alarm from the wireless slave device 5 is transmitted to the center device 1, it is sent to the wireless master device 2 via the wireless slave devices 4 and 3 existing at the upper level of the hierarchical structure. Similarly, when an alarm from the wireless slave unit 4 is transmitted to the center device 1, the alarm is sent to the wireless master unit 2 via the wireless slave unit 3 existing at the upper level of the hierarchical structure. On the other hand, when an alarm from the wireless slave unit 3 is transmitted to the center device 1, it is sent directly to the wireless master unit 2.

  Therefore, if the gas leak sensors connected to each of the wireless slave units 3 to 5 detect the same gas leak frequency, the wireless slave units that are higher in the hierarchical structure and the number of alarms to be transmitted increase. Power consumption also increases. However, in the present embodiment, by providing a difference in power consumption due to intermittent reception, it is possible to reduce variations in power consumption due to differences in the number of alarm transmissions.

  Furthermore, if the wireless slave devices 3 to 5 are configured to count and store the number of transmissions of meter reading data and the number of transmissions of alarms, and periodically correct the intermittent reception interval according to the number of transmissions. In addition, it is possible to more accurately correct the variation in power consumption caused by the difference between the meter reading data of the wireless slave devices 3 to 5 and the number of times of alarm transmission.

  Thus, according to the communication system of the present embodiment, “intermittent reception interval (4a) of the wireless slave unit 3> intermittent reception interval (3a) of the wireless slave unit 4> intermittent reception interval (2a) of the wireless slave unit 5”. Therefore, it is possible to reduce the variation in power consumption caused by the difference in the number of meter reading data and alarm transmission times of the wireless slave units 3 to 5, and the variation in the battery consumption speed of the wireless slave units 3 to 5 can be reduced. Can be suppressed. Thereby, since the exchange time of the wireless subunit | mobile_units 3-5 can be match | combined, work man-hours can be reduced. The data for setting these intermittent reception intervals may be configured so that the user individually writes the data in the memory 16 of each wireless slave when constructing the communication system. You may comprise so that it may write in the memory 16 of a radio | wireless subunit | mobile_unit.

  In the above description, the wireless master device 2 is not connected to a meter or a gas leak sensor. However, the wireless master device 2 may be connected to transmit meter reading data or an alarm. Further, in the case of the wireless master device 2, data communication with the center device 1 is performed via a communication line such as a mobile phone network, so that the power consumption is higher than that of the wireless slave device 3. However, according to the present embodiment, since “intermittent reception interval (5a) of wireless master device 2> intermittent reception interval (4a) of wireless slave device 3” is set, the difference in power consumption can be reduced. it can.

[Second Embodiment]
FIG. 7 is a diagram illustrating a configuration of a wireless communication system according to the second embodiment of this invention. The wireless communication system includes a center device 100, a wireless master device 101, and wireless slave devices 102 to 117. The center device 100 and the wireless master device 101 perform data communication through a communication line such as a mobile phone network.

  The wireless master device 101 performs data communication with the wireless slave devices 102 and 103 existing immediately below the hierarchical structure by using a specific low-power wireless device or the like. The wireless slave devices 102 to 117 perform data communication with a wireless slave device that exists immediately below and directly above each hierarchical structure using a specific low-power radio. However, the wireless slave devices (107, 108, 112 to 117) in which no wireless slave device exists immediately below perform data communication only with the wireless slave device directly above. The wireless slave units 102 to 117 are connected to a gas meter, a water meter, a gas leak sensor, and the like.

  Also in this embodiment, as in the first embodiment, the wireless master device 101 has a hierarchical structure with the highest rank, and the meter reading data of wireless slave devices other than the wireless slave devices 102 and 103 immediately below the wireless master device 101 is provided. Since the alarm and the alarm are delivered to the wireless master device 101 via the wireless slave device existing above the wireless slave device, a difference occurs between the meter reading data and the number of times the alarm is transmitted. Therefore, as in the first embodiment, by providing a difference in the intermittent reception interval of the wireless slave unit, variation in power consumption due to a difference in the number of meter reading data and the number of alarm transmissions is reduced.

  FIG. 8 is a flowchart showing a procedure for setting the standby interval (intermittent reception interval) and calling time (start command transmission time) of the wireless master device 101 and the wireless slave devices 102 to 117. This procedure is executed by the center apparatus 100 when the communication system is constructed.

  First, the number of communications of each terminal device is obtained based on the connection relationship of each terminal device (wireless master device, wireless slave device) in the communication system (step ST1). Here, the connection relationship is the hierarchical structure shown in FIG. The number of communications is the number of times each terminal device transmits meter reading data when the center device 100 collects meter reading data of all the terminal devices (wireless slave devices 102 to 117 and the wireless master device 101). In the present embodiment, since the terminal device present in the higher order collects the meter reading data of the terminal device present in the lower order and its own meter reading data and transmits it to the higher order terminal device, the number of transmissions of the meter reading data of each terminal device Is the sum of the number of terminal devices directly below and above itself. Therefore, the table shown in FIG. 9A is created by step ST1.

  Next, based on the number of communication times of each terminal device, the terminal devices are divided into n groups (n is an integer of 2 or more) (step ST2), and groups G1 to Gn are set in order of the smaller number of communication times (step ST3). . Here, since the number of times of communication is 1 to 4, it is divided into four groups G1 to G4, and the table shown in FIG. 9B is created. G1 to G4 entered in the wireless master device 101 and the wireless slave devices 102 to 117 in FIG. 8 are the group names.

  Next, with reference to the table shown in FIG. 9D registered in advance, the standby interval and the calling time of each terminal device are obtained (step ST4). Finally, the obtained waiting interval and calling time are written in the memory 16 of each terminal device as initial setting values. The unit of the standby interval and the calling time in FIG. 9D is both sec (seconds).

  Here, the standby interval and the calling time of each group have the relationship shown in FIG. 9C. That is, the greater the number of communications, the shorter the call time and the longer the waiting interval. Therefore, similarly to the first embodiment, it is possible to reduce the variation in power consumption caused by the difference in the number of times the meter reading data is transmitted.

  Further, in the present embodiment, the center device 100 counts the number of meter reading data transmissions and the number of alarm transmissions of each terminal device, periodically compares the count value with the number of communications shown in FIG. 9A, and the difference is a predetermined threshold value. If there is a terminal device exceeding this value, the initially set group is updated based on the measured value of the number of communications, and the updated group is referred to the table shown in FIG. The standby interval and the calling time are obtained and written in the memory 16. Thereby, the variation in the power consumption resulting from the difference between the meter reading data of each terminal device and the number of times of alarm transmission can be corrected more accurately.

  In the table of FIG. 9D, when there are a plurality of groups, the longer the waiting interval, the shorter the calling time. However, the calling time of all the groups is set to the calling time of the group with the shortest waiting interval. Also good. That is, for example, when the number of groups is 4, the calling time of the groups G1 to G4 may be set to 80 seconds.

It is a figure which shows the structure of the radio | wireless communications system of the 1st Embodiment of this invention. It is a block diagram which shows the structure of the radio | wireless subunit | mobile_unit of FIG. It is a sequence diagram which shows the procedure in which the center apparatus of the 1st Embodiment of this invention collects the meter-reading data of the meter connected to the radio | wireless subunit | mobile_unit. It is a timing diagram which shows the procedure in which the center apparatus of the 1st Embodiment of this invention collects the meter-reading data of the meter connected to the wireless cordless handset. It is a sequence diagram which shows the procedure which transmits an alarm from the radio | wireless subunit | mobile_unit of the 1st Embodiment of this invention to a center apparatus. It is a timing diagram which shows the procedure which transmits an alarm from the radio | wireless subunit | mobile_unit of the 1st Embodiment of this invention to a center apparatus. It is a figure which shows the structure of the radio | wireless communications system of the 2nd Embodiment of this invention. It is a flowchart which shows the procedure for setting the waiting space | interval and ringing time of the radio | wireless main | base station of the 2nd Embodiment of this invention and a radio | wireless slave | mobile_unit. It is a figure which shows the table etc. which are produced | generated by the procedure shown in FIG. It is a figure which shows the structure of the conventional radio | wireless communications system. It is a figure which shows the structure of the radio | wireless communications system which has a some radio | wireless subunit | mobile_unit.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,100 ... Center apparatus, 2,101 ... Wireless master machine, 3-5, 102-117 ... Wireless slave machine, 11 ... Control apparatus, 18 ... Timer for intermittent reception, 19 ... Start command timer.

Claims (5)

  A wireless communication system for wirelessly connecting a plurality of wireless communication terminal devices having an intermittent reception function so as to have a hierarchical structure, comprising means for setting an intermittent reception interval of the wireless communication terminal devices according to the hierarchical structure A wireless communication system.   2. The radio communication system according to claim 1, wherein the means sets the intermittent reception interval according to the number of radio communication terminal apparatuses existing in a lower level of the radio communication terminal apparatus.   2. The radio communication system according to claim 1, wherein the means sets the intermittent reception interval in accordance with the number of radio communication terminal devices existing immediately below and immediately above the radio communication terminal device.   4. The wireless communication system according to claim 1, further comprising means for setting a calling time from the wireless communication terminal device to another wireless communication terminal device according to the hierarchical structure. .   5. The wireless communication system according to claim 1, further comprising means for correcting the set intermittent reception interval and call time according to the number of communications of the wireless communication terminal device. Communications system.

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