JP5480691B2 - Wireless communication system - Google Patents

Description

  The present invention relates to a radio communication system including a plurality of radio stations, and more particularly to a radio communication system in which each radio station operates using a battery as a power source.

  For radio stations used in Japan, the characteristics of radio waves used (RF characteristics) such as occupied frequency bandwidth and adjacent channel leakage power must satisfy the provisions of the Radio Law. In the Radio Law, different standards (communication standards) are defined for each purpose of use. For example, “low-power radio stations” defined as one of the radio stations that do not require a license in the proviso to Article 4 of the Radio Law include “wireless stations for cordless telephones”, “specified low-power radio stations”, “low-power radio stations” There are “security system”, “low-power data communication system radio station”, etc., and the standards for the radio equipment of each radio station are stipulated by the equipment regulations of the law.

  Conventionally, there is one described in Patent Document 1 as a wireless communication system including a plurality of wireless stations that operate using a battery as a power source. In the conventional system described in Patent Document 1, each radio station intermittently activates a reception circuit to check whether or not a desired radio wave (a radio signal transmitted by another radio station) can be received. If radio waves are not captured, the average power consumption is greatly reduced by immediately stopping the receiving circuit and shifting to a standby state.

  However, when the intermittent reception operation is performed as described above, the timing of receiving the radio signal that should be received is delayed by the intermittent reception interval of the reception circuit. Therefore, the intermittent reception interval cannot be simply extended for the purpose of reducing power consumption. In addition, since the timings at which the intermittent reception interval starts at a plurality of radio stations usually do not coincide with each other, the timing at which each radio station activates a receiving circuit and receives radio waves is also uneven.

  On the other hand, the present inventors transmit a synchronization signal from any one of the radio stations at a constant period (however, a period sufficiently longer than the intermittent reception interval), and each radio station receives the signal intermittently based on the synchronization signal. There has already been proposed a wireless communication system in which the interval count start timing is aligned. According to such a conventional system, intermittent reception is performed to reduce power consumption and extend battery life, while shortening a delay time until another radio station can receive a radio signal transmitted from one of the radio stations. be able to.

JP 2008-176515 A

  By the way, the intermittent reception interval in the conventional system is counted by counting a clock signal input from a clock circuit (oscillation circuit) externally attached to the microcontroller provided in the wireless station. For such a clock circuit, a tuning fork type crystal resonator (frequency is about 32 kilohertz) having a frequency deviation of about several tens of ppm is usually used. Therefore, if the intermittent reception interval is counted by the clock signal with such low accuracy, it is difficult for each wireless station to maintain synchronization of the intermittent reception interval over a long period of time.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a wireless communication system that can synchronize the intermittent reception interval in each wireless station over a longer period than before.

In order to solve the above-mentioned problem, the first invention is a wireless communication system comprising a plurality of wireless stations, and transmitting and receiving a wireless signal using a radio wave as a medium between the plurality of wireless stations, A transmission / reception unit for transmitting / receiving a radio signal; a timer unit for repeatedly counting a certain intermittent reception interval; and a transmission / reception unit that is activated when a predetermined event occurs, and includes a message corresponding to the event during a predetermined transmission period An operation of alternately transmitting a radio signal and pausing transmission of a radio signal during a predetermined pause period is repeated, and when the event does not occur, the transmission / reception unit is stopped, and further, the intermittent reception interval of the timer unit is set. The transmission / reception means is stopped during the counting, and the transmission / reception is performed each time the intermittent reception interval is counted by the timer means. A transmission / reception control means for activating the stage; and a power supply means for supplying an operating power for each means using a battery as a power supply, wherein the transmission / reception control means receives the synchronization signal by the transmission / reception means. Stop counting the intermittent reception interval, restart the counting of the intermittent reception interval by the timer means when a certain waiting time has elapsed from the end of the synchronization signal, and when the event occurs, In the wireless communication system in which a wireless signal is transmitted from the transmission / reception means in the transmission period overlapping with the time point when the counting of the intermittent reception interval by the timer means is completed, the transmission / reception control means of a specific wireless station among the plurality of wireless stations Transmits a synchronization signal from the transmission / reception means periodically at a period sufficiently longer than the intermittent reception interval. Both were transmitted multiple times in a cycle synchronized with the intermittent reception interval when sending the synchronization signal, the other the transmission and reception control means of the radio station, except for the specific radio station, the synchronization transmitted multiple times in the period When the signal is received by the transmitting / receiving means, the reception interval of the plurality of synchronization signals is measured, and the intermittent reception interval of itself is matched with the measured value of the reception interval.

  According to a second aspect, in the first aspect, the transmission / reception control unit of the other radio station causes the radio signal including a response request message to be transmitted from the transmission / reception unit to the specific radio station. The transmission / reception unit waits in a reception state after signal transmission, and the transmission / reception control unit of the specific radio station transmits a radio signal including a response message to the response request message from the transmission / reception unit, The transmission / reception control unit of the other radio station measures the reception interval of the synchronization signal when receiving the synchronization signal by the transmission / reception unit and transmits the synchronization signal a plurality of times in the cycle. Is matched with the measured value of the reception interval.

  According to the present invention, the intermittent reception interval in a specific wireless station that transmits a synchronization signal can be matched with the intermittent reception intervals in other wireless stations excluding the specific wireless station. The interval can be synchronized over a longer period than before.

It is a block diagram of a fire alarm device (parent device and child device) in an embodiment of the present invention. It is a frame format of the radio signal in the same as above. It is a flowchart for demonstrating the operation | movement which changes to a fire interlocking state from a standby state same as the above. It is a time chart for demonstrating the operation | movement which changes to the interlocking stop state from the interlocking ringing state same as the above. It is a time chart for demonstrating the operation | movement which changes to the interlocking stop state from the interlocking ringing state same as the above. It is a time chart for demonstrating the operation | movement which changes to a standby state from a fire interlocking state same as the above. It is a time chart for demonstrating the operation | movement in a fire interlocking state same as the above. It is operation | movement explanatory drawing at the time of transmission / reception of the synchronizing signal in the same as the above. It is a sequence diagram for demonstrating operation | movement of the registration operation | work in the same as the above.

  The technical idea of the present invention will be described below for a radio communication system (fire alarm system) in which a fire alarm is generated by detecting a fire and sounding an alarm sound and using radio waves as a medium and transmitting a radio signal including a fire alarm message. An embodiment to which is applied will be described.

  FIG. 1 is a system configuration diagram of the present embodiment, and a fire alarm system is configured by a plurality (only two in the drawing) of fire alarms TR. In the following description, when the fire alarms TR are individually indicated, they are indicated as fire alarms TR1, TR2,..., TRn, and when collectively indicated, they are indicated as fire alarms TR.

  The fire alarm TR includes a control unit 1 that is a transmission / reception control unit, a wireless transmission / reception unit 2 and an antenna 3 that are transmission / reception units, an oscillator 6 that oscillates a clock signal with a fixed period, a battery power supply unit 8 that is a power supply unit, and a fire detection unit. 4, the alarm part 5, the operation input reception part 7, etc. are provided.

  The radio transmission / reception unit 2 transmits / receives a radio signal using radio waves as a medium in accordance with “radio station of low power security system” defined in Article 6, Paragraph 4, Item 3 of the Radio Law Enforcement Regulations. For example, it is composed of a commercially available LSI for low-power wireless communication.

  The fire sensing unit 4 senses a fire by detecting smoke, heat, flame, etc. generated by the fire, for example. However, the detailed configuration of such a fire detection unit 4 is well known in the art and will not be described in detail.

  The alarm unit 5 notifies (fires from a speaker) a fire alarm (hereinafter referred to as “alarm sound”) by sound (such as a buzzer sound or a voice message). The operation input receiving unit 7 includes one or more switches (for example, push button switches), and outputs an operation input (operation signal) corresponding to each switch to the control unit 1 when the switch is operated. The battery power supply unit 7 supplies operation power to each unit using a battery such as a dry battery as a power source.

  The control unit 1 includes a memory unit 1a including a microcontroller (hereinafter abbreviated as a microcomputer), a rewritable nonvolatile semiconductor memory, and the like as main components. In the control unit 1, when the fire detection unit 4 detects a fire, the alarm unit 5 sounds an alarm sound and transmits a radio signal including a fire alarm message for notifying other fire alarms TR of the fire alarm. The wireless transmission / reception unit 2 transmits the data. The control unit 1 also controls the alarm unit 5 to sound an alarm sound when receiving a fire alarm message by receiving a radio signal transmitted from another fire alarm device TR by the radio transmission / reception unit 2. Each of the fire alarms TR1, TR2,... Is assigned a unique identification code and stored in the memory unit 1a. The destination of the radio signal and the source fire alarms TR1, TR2,. Can be identified.

  The oscillator 6 oscillates an operation clock (clock signal) of a microcomputer constituting the control unit 1 using a tuning fork type crystal resonator. However, since the circuit configuration of the oscillator 6 is well known in the art, a detailed description thereof will be omitted.

  Here, in the radio equipment regulation Article 49-17 “Radio equipment of radio stations of the low power security system” of the Radio Law Enforcement Regulation, the period during which radio signals may be continuously transmitted (transmission period) is 3 seconds or less. It is stipulated that the period (pause period) provided between the transmission period and the transmission period in which the radio signal should not be transmitted is 2 seconds or more (see No. 5 of the same article). For this reason, in the control unit 1 in the present embodiment, the wireless signal is transmitted during the transmission period that complies with the wireless facility rules, and the transmission is stopped and received during the suspension period.

  Moreover, the control part 1 is performing the intermittent reception demonstrated by the prior art in order to lengthen the battery life of the battery power supply part 7 as much as possible. That is, the control unit 1 repeatedly counts a predetermined intermittent reception interval with a timer (timer means), and activates the wireless transmission / reception unit 2 every time the intermittent reception interval is counted, and activates a desired radio wave (other fire alarm TR It is checked whether or not the radio signal transmitted by can be received. And if the said electromagnetic wave is not caught, the control part 1 will stop the radio | wireless transmission / reception part 2 immediately, and will reduce average power consumption significantly by making it transfer to a standby state. The radio wave reception check is performed by the control unit 1 based on a received signal strength display signal (RSSI signal) which is a DC voltage signal output from the wireless transmission / reception unit 2 and proportional to the magnitude of the received signal strength.

  Further, the control unit 1 of a specific fire alarm device TR1 (hereinafter referred to as a parent device) activates the wireless transmission / reception unit 2 periodically (for example, every 24 hours), and other fire alarm devices TR2, TR3,. (Hereinafter referred to as a slave unit) is caused to transmit a radio signal including a regular monitoring message (response request message). In the child device TRi (i = 2, 3,...), The control unit 1 monitors the fire detection unit 4 for failure and the battery power supply unit 7 for battery breakage at regular intervals (for example, every hour). At the same time, the monitoring results (whether there is a failure and whether the battery has run out) are stored in the memory unit 1a. When a regular monitoring message is received from the parent device TR1, a radio signal including a notification message (response message) for notifying the monitoring result stored in the memory unit 1a is returned to the parent device TR1. After transmitting the radio signal including the notification message, the control unit 1 of the master unit TR1 switches the radio transmission / reception unit 2 to the reception state and receives the radio signal transmitted from each slave unit TRi. Then, the control unit 1 of the parent device TR1 determines that there is a child device TRi that does not transmit the notification message within a predetermined time from the transmission of the regular monitoring message, or when the monitoring result of the notification message is faulty or the battery is dead. A buzzer included in the alarm unit 5 is driven to sound a notification sound. As a result, it is possible to notify the user that an abnormality (communication failure, failure, battery exhaustion, etc.) has occurred in any slave unit TRi. When the control unit 1 of the master unit TR1 and the slave unit TRi determines that a failure or a battery has run out, the alarm unit 5 immediately gives a warning sound (such as a buzzer sound or a voice message) to notify the occurrence of an abnormality. Let it ring.

  The control unit 1 of the master unit TR1 transmits an alarm sound from the alarm unit 5 and transmits a fire alarm message to each slave unit TRi, or after receiving a fire alarm message from any slave unit TRi, is transmitted wirelessly. The unit 2 is caused to transmit a synchronous beacon at a constant cycle. This synchronous beacon is a signal that defines a time slot necessary for performing TDMA (time division multiple access) wireless communication (hereinafter referred to as “synchronous communication”) between a plurality of fire alarms TR. That is, one period (cycle) of the synchronous beacon is divided into a plurality of time slots, and one different time slot is allocated to each of the slave units TRi. The message from the parent device TR1 to the child device TRi is transmitted in the synchronization beacon, and the message from the child device TRi to the parent device TR1 is stored and transmitted in the time slot assigned to each child device TRi. The Therefore, collision of radio signals transmitted from a plurality of fire alarm devices TR (master device TR1 and slave device TRi) can be reliably avoided. The time slot assignment for each fire alarm device TR may be fixed, but the time slot assignment information may be notified to each child device TRi by a synchronous beacon transmitted from the parent device TR1.

  FIG. 2 shows a frame format of a radio signal transmitted and received by the fire alarm TR, including a synchronization bit (preamble: PA), a frame synchronization pattern (unique word: UW), a destination address DA, a source address SA, a message M, One frame is composed of the CRC code. Here, if the identification code of each fire alarm device TR is set as the destination address DA, only the fire alarm device TR of the identification code receives a radio signal and acquires a message. On the other hand, if a special bit string (for example, a bit string with all bits set to 1) that is not assigned to any fire alarm TR is set as the destination address DA, the wireless signal is broadcast (multicast) and all A message can be acquired by the fire alarm TR. For example, a radio signal including a fire alarm message is broadcast from the parent device TR1 to all the child devices TRi.

  Next, the transmission / reception operation of this embodiment before and after the fire detection will be described with reference to the time chart of FIG.

  Here, the timing at which each fire alarm device TR starts to operate (the timer starts counting the intermittent reception interval) does not normally match, so the timing at which the control unit 1 activates the wireless transmission / reception unit 2 to receive radio waves ( (See the downward arrow in FIG. 3). On the other hand, in the present embodiment, when the synchronization signal is received by the radio transmission / reception unit 2 of each fire alarm device TR, the control unit 1 stops the counting of the intermittent reception interval Tx by the timer and ends the synchronization signal ( When a certain waiting time Tw elapses from t = t0), the counting of the intermittent reception interval Tx by the timer is resumed. Therefore, after receiving the synchronization signal, the timing at which the timer finishes counting the intermittent reception interval Tx is set in each fire alarm device TR. The synchronization signal is transmitted from the master unit TR1, which is a specific fire alarm, as will be described later.

  For example, when the fire detection unit 4 detects a fire in the child unit TR2, the control unit 1 of the child unit TR2 sounds an alarm sound from the alarm unit 5 and sets the wireless transmission / reception unit 2 before the completion of the intermittent reception interval Tx by the timer. to start. Then, the control unit 1 of the slave unit TR2 transmits the radio signal including the fire alarm message to all the other fire alarm devices TR (the master unit TR1 and the other slave units TR3,...) Within the transmission period including the count completion time. Send to. At this time, the control unit 1 of the slave unit TR2 as the transmission source continuously transmits the radio signal by the number of frames that can be transmitted within the transmission period, and the radio transmission / reception unit 2 during the pause period (reception period) after the transmission period. To the receiving state. Since each fire alarm device TR has the timing to complete the intermittent reception interval Tx, it is possible to receive a radio signal including a fire alarm message in one transmission period.

  Here, if low-power radio is used, the wireless communication distance can be sufficiently covered as long as it is within an area of a normal house. Therefore, the child unit TR2 of the fire source is connected to other fire alarms TR (master unit TR1 and It is usually possible to send a message to other child units TR3,. Further, as described above, the parent device TR1 periodically monitors the child devices TR2 to TR4, and the normality of the communication path is confirmed between the parent device TR1 and each child device TR2 to TR4. . However, since the communication path between the child devices TR2 to TR4 is not confirmed, there is a possibility that a message does not reach a certain child device due to the influence of an obstacle, for example.

  Therefore, the control unit 1 of the master unit TR1 that has received the fire alarm message sends a radio signal including the fire alarm message to the other slave units TR3 and TR4 other than the slave unit TR2 that is the transmission source, and an intermittent reception interval Tx by the timer. It is transmitted in the transmission period including the time point of completion of When the control unit 1 of the other slave units TR3 and TR4 receives the fire alarm message transmitted from the slave unit TR2 or the master unit TR1, it immediately sounds an alarm sound from the alarm unit 5 and sends a fire alarm message from the wireless transceiver unit 2. A response message (ACK) for confirming reception is returned by a radio signal. In addition, when all of the fire alarms TR notify a fire alarm (sound an alarm sound) when a fire is detected by at least one fire alarm TR in this way, it is hereinafter referred to as “fire interlocking”. .

  When the control unit 1 of the parent device TR1 receives ACK from all the other child devices TR3 and TR4, the control unit 1 causes the wireless transmission / reception unit 2 to transmit a synchronization beacon for defining a time slot at a constant period. In the present embodiment, the first time slot TS1 is assigned to the child device TR2, the second time slot TS2 is assigned to the child device TR3, and the third time slot TS3 is assigned to the child device TR4.

  Here, the parent device TR1 regularly monitors each child device TR2 to TR4, and the normality of the communication path is confirmed between the parent device TR1 and each child device TR2 to TR4. The communication path between the devices TR2 to TR4 has not been confirmed. When a large number of slave units TRi are arranged, the number of communication paths between the slave units TRi becomes very large. Therefore, when the normality of the communication paths between the slave units TRi is confirmed, battery consumption becomes severe. Therefore, as described above, a specific fire alarm device TR1 is used as a parent device, and other fire alarm devices TRi are used as child devices, so that a fire alarm message and other messages (described later) are notified from the parent device TR1 to each child device TRi. Thus, even if there are slave units that cannot establish a communication path with each other, it is possible to make sure that the fire is linked.

  When all the fire alarm devices TR sound an alarm sound, the synchronization is started, and as described above, a synchronization beacon is transmitted from the master device TR1 at a constant cycle, and the operation shifts to TDMA synchronous communication. In the synchronous communication, the control unit 1 of the parent device TR1 repeatedly transmits a fire alarm message to all the child devices TRi at regular intervals by being included in the synchronization beacon. And the control part 1 of each subunit | mobile_unit TRi confirms the state of the alarm part 5 whenever it receives the fire alarm message transmitted from the main | base station TR1, and if the alarm part 5 has stopped temporarily, it will ask the alarm part 5 again. Sound an alarm sound. Therefore, after fire alarms are started to be notified by all fire alarms TR, all other fire alarms (children) are placed in multiple time slots defined by the synchronized beacon transmitted by a specific fire alarm (master) TR1. ) Collision can be avoided by assigning TRi and performing wireless communication using time division multiple access (TDMA). In addition, the fire alarm message is included in the synchronous beacon periodically and sent to all other fire alarms (child units) TRi from a specific fire alarm (master unit) TR1. can do. As a result, a plurality of fire alarms TR can be effectively linked while avoiding radio signal collision.

  As described above, according to the present embodiment, since a fire alarm is notified by all the fire alarms TR in the event of a fire, the user has more opportunities to perceive the fire alarm (listen to the alarm sound), thereby increasing safety. Can be improved.

  By the way, the fire alarm system of this embodiment transits three operation states of a standby state, an interlocking ringing state, and an interlocking stop state. The standby state is a state in which no fire is detected in any fire alarm TR. The interlocking sounding state is a state where all the fire alarms TR are sounding an alarm sound. In addition, the interlock stop state means that only the fire alarm TR that detects fire (fire source) sounds the alarm sound and the fire alarm devices TR other than the fire source stop the alarm sound as described later. State. That is, when a fire is detected by at least one of the fire alarm devices TR (eg, child device TR2) in the standby state, as described above, all the other children from the fire child device TR2 and the parent device TR1. When the fire alarm message is transmitted to the devices TR3,..., An alarm sound is generated in all the fire alarm devices TR including the parent device TR1 and the child devices TR2,.

  When the operation input for stopping the alarm sound is received by the operation input receiving unit 7 of any fire alarm device TR in the interlocking sounding state, if the fire alarm device TR is the master device TR1, A message (alarm stop message) requesting stop of the alarm sound is transmitted from the device TR1 to all the child devices TRi. Alternatively, if the fire alarm device TR is the child device TRi, the parent device TR1 that has received the alarm stop message from the child device TRi transmits an alarm stop message to the other child devices TRi. Then, when the alarm stop message is received by the fire alarm device TR other than the fire source, the alarm sound of the alarm unit 5 is stopped and a transition to the interlock stop state is made. However, when an operation input for stopping the alarm sound is received by the operation input receiving unit 7 of the fire alarm device TR of the fire source, the alarm sound is also stopped in the fire alarm device TR of the fire source. Here, the control unit 1 of the master unit TR1 holds the fire detection status for each master unit TR1 and each slave unit TRi in the memory unit 1a while being updated as needed. Transition from the fire interlocking state to the standby state when no longer occurs.

  Further, when the interlocking sounding state is changed to the interlocking stop state, the control unit 1 of the parent device TR1 starts a time limit for a predetermined alarm sound stop time (for example, 5 minutes). After the alarm sound stop time has elapsed, the control unit 1 of the master unit TR1 refers to the fire detection status held in the memory unit 1a, and if all the fire alarms TR do not detect a fire, the control unit 1 Transition from the fire-linked state to the standby state by sending a recovery notification message using a beacon. On the other hand, if a fire is detected by at least one fire alarm device TR, a fire alarm message is transmitted by a synchronous beacon to make a transition from the interlock stop state to the interlock ringing state. Even if any fire alarm TR detects a new fire in the interlock stop state, the control unit 1 of the master unit TR1 transmits the fire alarm message by the synchronous beacon to switch from the interlock stop state to the interlock ringing state. Transition.

  For example, as shown in the time chart of FIG. 4, in a fire-linked state (linked ringing state) in which the parent device TR1 is a fire source, an operation input for stopping an alarm sound is received by the operation input reception unit 7 of the child device TR4 that is not a fire source When the alarm stop message is transmitted from the child unit TR4 by being accepted, the control unit 1 of the master unit TR1 that has received the alarm stop message transmits the alarm stop message M2 by the synchronous beacon and sets the time limit of the alarm sound stop time. Do. However, in the master unit TR1 that is the source of fire, the alarm unit 5 continues to sound an alarm sound. After the alarm sound stop time has elapsed, the control unit 1 of the parent device TR1 confirms the fire detection status of its own fire detection unit 4 and the fire detection status of the child device TRi. When at least one of the fire alarms TR detects a fire, the control unit 1 of the master unit TR1 transmits a fire alarm message to each slave unit TRi again by using a synchronous beacon so that the slave unit TR1 can be stopped. Transition to the linked ringing state.

  On the other hand, as shown in the time chart of FIG. 5, if the fire is extinguished within the alarm sound stop time and the fire detection unit 4 stops detecting the fire, the control unit 1 of the master unit TR1 After the elapse, a recovery notification message is transmitted to each slave unit TRi by a synchronous beacon. When the ACK returned from all the slave units TRi is received, the control unit 1 of the master unit TR1 shifts from the interlock stop state to the standby state, and stops the transmission of the synchronous beacon, thereby performing wireless communication by the TDMA method. Return to wireless communication by intermittent transmission and reception.

  In addition, as shown in the time chart of FIG. 6, if the fire of the fire source is extinguished and the fire detection unit 4 of the child device TR4 does not detect the fire in the interlocking ringing state using the child device TR4 as the fire source, A recovery notification message is transmitted from the device TR4 to the parent device TR1. The control unit 1 of the master unit TR1 that has received the recovery notification message refers to the fire detection status held in the memory unit 1a. If no fire is detected by all the fire alarms TR, the recovery notification message is sent by a synchronous beacon. M3 is transmitted to each slave unit TRi. When the control unit 1 of the master unit TR1 receives ACKs returned from all the slave units TRi, the state transitions from the interlocking stop state to the standby state, and the transmission of the synchronous beacon is stopped, thereby intermittently starting the wireless communication by the TDMA method. Return to wireless communication by transmission and intermittent reception.

  On the other hand, as shown in the time chart of FIG. 7, when a fire is newly detected by another fire alarm device (eg, child device TR3), a recovery notification message is received from the child device TR4 which is the first fire source. The control unit 1 of the parent device TR1 refers to the fire detection status held in the memory unit 1a. At this time, the control unit 1 of the parent device TR1 does not transmit the recovery notification message because the child device TR3 is detecting a fire, and continues to transmit the fire alarm message to maintain the fire-linked state.

  Here, in this embodiment, the timing which the control part 1 of each fire alarm device TR starts the radio | wireless transmission / reception part 2 is prepared by receiving a synchronizing signal. In addition, since the control unit 1 of the fire alarm device TR that has detected a fire transmits a radio signal in accordance with the activation timing, all the other fire alarm devices TR transmit the radio signal transmitted from one fire alarm device TR. It can be received almost simultaneously. As a result, the delay time until another fire alarm TR can receive the radio signal transmitted by one of the fire alarms TR while shortening the power consumption and extending the battery life by performing intermittent reception is shortened. be able to.

  Moreover, every time the transmission / reception control means (control unit 1) of a specific radio station (master unit TR1) among a plurality of radio stations (fire alarm device TR) completes the count of the intermittent reception interval by the timer means a predetermined number of times. If the synchronization signal is transmitted from the transmission / reception means (wireless transmission / reception unit 2), there is an advantage that a dedicated transmitter (transmission station) or the like for transmitting the synchronization signal is unnecessary and the system configuration can be simplified.

  In the present embodiment, since a specific radio station (master device TR1) transmits a radio signal including a regular monitoring message to other radio stations (child device TRi) at a constant period, the regular radio message is included. A radio signal may also be used as a synchronization signal.

  By the way, the intermittent reception interval is counted by counting the operation clock (the clock signal oscillated by the oscillator 6; the same shall apply hereinafter) by the microcomputer constituting the control unit 1. Since the vibration frequency of the tuning-fork type crystal resonator used for the oscillator 6 (= the oscillation frequency of the oscillator 6) is generally 32.768 kHz, for example, when the intermittent reception interval is 10 seconds, the control unit 1 is for operation. Intermittent reception is performed every time the clock is counted 327680 (= 32.768kHz × 10s). However, the frequency stability (frequency deviation) of the tuning fork type crystal resonator is about several tens of ppm, and there are individual differences. Therefore, when a tuning-fork type crystal resonator with a large frequency deviation is used for the oscillator 6, the time difference of the intermittent reception interval gradually increases due to long-term use, and synchronization is performed between the parent device TR1 and the child device TRi. There is a possibility that the intermittent reception interval by the signal cannot be synchronized.

  Therefore, in this embodiment, in order to make the intermittent reception interval Tx timed by the control unit 1 of the parent device TR1 coincide with the intermittent reception interval Tx timed by the control unit 1 of the child device TRi, the control unit of the parent device TR1. 1 and the control unit 1 of the slave unit TRi perform the following processing, respectively.

  First, as shown in FIG. 8A, the control unit 1 of the master unit TR1 transmits a plurality of times at a period synchronized with the intermittent reception interval Tx when transmitting a synchronization signal (three transmissions in the illustrated example). At this time, the transmission period of the synchronization signal coincides with the intermittent reception interval Tx in the parent device TR1.

  On the other hand, the control unit 1 of the slave unit TRi continues the reception state of the wireless transmission / reception unit 2 for a while after receiving the synchronization signal as shown in FIG. 8 (b), and is transmitted a plurality of times from the master unit TR1. Are received, and the reception interval of each synchronization signal, that is, the intermittent reception interval Tx in the parent device TR1 is measured. Then, the control unit 1 of the slave unit TRi makes its own intermittent reception interval Tx (count number of operation clocks) coincide with the measured value of the reception interval of the synchronization signal. For example, if the intermittent reception interval is 10 seconds, the intermittent reception interval Tx should be counted if the operation clock is counted 327680 (= 32.768 kHz × 10 s), but if the measured value is 327681 When the operation clock is counted 327681, the intermittent reception interval Tx is corrected to be completed.

  By matching the intermittent reception interval Tx timed by the control unit 1 of the parent device TR1 with the intermittent reception interval Tx timed by the control unit 1 of the child device TRi as described above, each fire alarm device TR The intermittent reception interval Tx can be synchronized over a longer period than before. The above-described processing may be performed every time a synchronization signal is transmitted, but may be performed every 1 to several weeks or every 1 to several months.

  By the way, in this embodiment, work (registration work) in which the parent device TR1 and the child device TRi register each other's identification code is required before the operation of the system is started. This registration work is started when the operation input of the registration work is received by the operation input receiving unit 7 in each of the parent device TR1 and the child device TRi. Hereinafter, the registration work will be described with reference to the sequence diagram of FIG.

  When the operation input for registration work is received by the operation input receiving unit 7, the control unit 1 of the slave unit TRi shifts to the registration mode and transmits a radio signal including a registration request message (response request message) from the radio transmitting / receiving unit 2. Send (multicast). When the operation input for the registration work is received by the operation input receiving unit 7, the control unit 1 of the parent device TR1 sets the wireless transmission / reception unit 2 to the reception state. When the wireless signal transmitted from the child device TRi is received by the wireless transmission / reception unit 2, the control unit 1 of the parent device TR1 stores the transmission source address (identification code of the child device TRi) of the wireless signal including the registration request message. The wireless signal including the registration command is transmitted from the wireless transmission / reception unit 2 to the slave unit TRi while being stored in the unit 1a.

  When the wireless signal transmitted from the parent device TR1 is received by the wireless transmission / reception unit 2, the control unit 1 of the child device TRi receives the transmission source address (identification code of the parent device TR1) of the wireless signal including the registration command message in the memory unit 1a. , The wireless signal including the ACK (response message) is returned from the wireless transmission / reception unit 2 to the parent device TR1, and then the registration mode is terminated and the wireless transmission / reception unit 2 is set in the reception state. When the radio signal including the ACK transmitted from the child device TRi is received by the wireless transmission / reception unit 2, the control unit 1 of the parent device TR1 transmits the synchronization signal a plurality of times at a period synchronized with the intermittent reception interval Tx. Note that the control unit 1 of the parent device TR1 ends the registration mode after transmission of the synchronization signal is completed. Then, the control unit 1 of the slave unit TRi measures the reception interval of the synchronization signal transmitted from the master unit TR1, and sets the measurement value to its own intermittent reception interval Tx. As a result, the intermittent reception interval Tx between the parent device TR1 and the child device TRi can be made to coincide with each other from the start of system operation.

TR1 Fire alarm (master unit)
TR2 Fire alarm (child unit)
1 Control unit (transmission / reception control means, timer means)
2 Radio transceiver (transmission / reception means)
6 Oscillator 7 Battery power supply (power supply means)

Claims (2)

A wireless communication system comprising a plurality of wireless stations and transmitting and receiving wireless signals using radio waves as a medium between the plurality of wireless stations,
Each radio station transmits / receives a radio signal, timer means for repeatedly counting a certain intermittent reception interval, and activates the transmitter / receiver when a predetermined event occurs, and the event is transmitted during a predetermined transmission period. The operation of transmitting and receiving a radio signal including a message corresponding to the above and repeating the operation of pausing the transmission of the radio signal during a predetermined pause period and stopping the transmission / reception means when the event has not occurred, further, the timer means The transmission / reception means is stopped during counting of the intermittent reception interval by the transmission / reception control means for starting the transmission / reception means each time counting of the intermittent reception interval by the timer means is completed; Power supply means for supplying operating power,
The transmission / reception control means stops counting the intermittent reception interval by the timer means when the synchronization signal is received by the transmission / reception means, and the timer when a certain waiting time has elapsed since the end of the synchronization signal. The counting of the intermittent reception interval by the means is restarted, and if the event occurs, a radio signal is transmitted from the transmission / reception means during the transmission period overlapping with the time when the counting of the intermittent reception interval by the timer means is completed. In a wireless communication system,
The transmission / reception control unit of a specific radio station of the plurality of radio stations periodically transmits a synchronization signal from the transmission / reception unit at a period sufficiently longer than the intermittent reception interval, and at the time of transmission of the synchronization signal Transmit multiple times at a period synchronized with the intermittent reception interval,
The transmission / reception control means of other wireless stations excluding the specific wireless station measures the reception interval of the synchronization signal of a plurality of times when the synchronization signal transmitted a plurality of times in the period is received by the transmission / reception means. A wireless communication system characterized in that its intermittent reception interval coincides with a measurement value of the reception interval. The transmission / reception control unit of the other radio station causes the radio signal including a response request message to be transmitted from the transmission / reception unit to the specific radio station, and waits for the transmission / reception unit in a reception state after the transmission of the radio signal. Let
The transmission / reception control unit of the specific radio station transmits a radio signal including a response message to the response request message from the transmission / reception unit, and then transmits the synchronization signal a plurality of times in the cycle.
The transmission / reception control unit of the other radio station measures the reception interval of the synchronization signal when the transmission / reception unit receives the synchronization signal, and matches its intermittent reception interval with the measurement value of the reception interval. The wireless communication system according to claim 1.

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