JP4848963B2 - Wireless transmission system - Google Patents

Description

  The present invention relates to a wireless transmission system for transmitting a wireless signal between a plurality of wireless devices.

  For radio equipment used in Japan, the characteristics of radio waves used (RF characteristics) such as occupied frequency bandwidth and adjacent channel leakage power must satisfy the regulations of the Radio Law. In the Radio Law, different standards (communication standards) are defined for each purpose of use. For example, the “specified low-power radio station” defined in Article 6 of the Radio Law Enforcement Regulations uses a telemeter for automatically displaying or recording the measurement results of remote measuring devices using radio waves. , For telecontrol that transmits signals for the purpose of starting, changing or terminating the function of a device at a remote point using radio waves, and transmission of information processed mainly by machines or transmission of processed information "Specified low-power radio station telemeter, telecontrol and data transmission radio equipment standard (Radio Industry Association Standard ARIB STD-T67)" or mainly fire "Small power," which is defined for wireless facilities of low power security systems that report theft or other abnormalities Curie tee system of the radio station radio equipment standards (Association of Radio Industries and Businesses Standard RCR STD-30) ", and the like.

  On the other hand, as a radio transmission system provided with the specific low-power radio station, there is a fire alarm system described in Patent Document 1, for example. Such a fire alarm system has a function in which a plurality of fire detectors (radio units) installed in many places sense a fire and sound a warning sound. When a fire is detected, the fire detector sounds an alarm sound and transmits information (fire detection information) to notify the fire detection to other fire detectors by wireless signals, so that not only the fire source fire detector. A plurality of fire detectors interlock and sound an alarm sound all at once, so that the occurrence of a fire can be notified quickly and reliably.

Such a fire detector (wireless device) is driven by a battery in order to take advantage of the characteristic of transmitting fire detection information with a radio signal, and is usually used for maintenance (battery replacement) like an indoor ceiling. Since it is installed in a difficult place, it is desirable that it can be used without maintenance for a long period of time such as several years. Therefore, each fire detector intermittently activates a receiving circuit to check whether or not a desired radio wave (a radio signal transmitted by another fire sensor) can be received. It is desired to significantly reduce the average power consumption by stopping the receiving circuit and shifting to the standby state.
JP 2006-343983 A

  However, when the intermittent reception operation is performed as described above, the timing of receiving the wireless signal that should be received originally is delayed by the intermittent reception interval of the reception circuit, and the response speed in the interlocking operation becomes slow. End up. Therefore, the intermittent reception interval cannot be simply extended for the purpose of reducing power consumption. For example, if the delay period until interlocking is to be suppressed to about 6 to 10 seconds at the maximum, at least the intermittent reception interval is set to 10 seconds or less. There is a need to. That is, in order to ensure the response speed required in practice, it is necessary to perform the reception operation to some extent frequently. In the above-mentioned standard for the specific low power radio station, a period during which radio waves can be continuously transmitted from the radio station (radio device) (transmission period) and a period during which radio waves are not transmitted (pause period) are defined. In order to comply with this rule, the fire detector of the fire source can also transmit a radio signal only during the transmission period, which may result in a slow response speed. Note that even in a wireless transmission system other than the fire alarm system, while one of the wireless devices is transmitting a wireless signal, the other wireless device cannot transmit the wireless signal, so the transmission period cannot be made too long. .

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a wireless transmission system capable of reducing the delay time of information transmission while reducing the power consumption of the wireless device.

In order to achieve the above object, a first aspect of the present invention is a wireless transmission system including a plurality of wireless devices and transmitting wireless signals between the plurality of wireless devices, wherein each wireless device transmits a wireless signal. At least one of transmitting means for transmitting or receiving means for receiving a radio signal and a battery for supplying power are commonly provided, and the wireless device including the transmitting means transmits when a predetermined event occurs. And a transmission control means for stopping the transmission means when the event does not occur and alternately repeating the operation of transmitting a radio signal during a predetermined transmission period and stopping the transmission of the radio signal during a predetermined pause period. A radio unit equipped with a receiving means, a timer means for repeatedly counting a constant intermittent reception interval, and the reception means is stopped during the counting of the intermittent reception interval by the timer means Allowed, provided with a reception control means for counting the intermittent receiving interval by the timer means starts receiving means every time to complete, the transmission period a, when the suspension periods is b, the intermittent reception interval T is T> a It is characterized in that values a and b satisfying a + 2b <T and 2a + b> T under the condition of > b are set in the transmission period and the pause period, respectively.

  The invention of claim 2 is characterized in that, in the invention of claim 1, the transmission period a is less than 3 seconds and the pause period b is longer than 2 seconds.

In order to achieve the above object, a third aspect of the present invention provides a wireless transmission system including a plurality of wireless devices and transmitting wireless signals between the plurality of wireless devices, wherein each wireless device transmits a wireless signal. At least one of transmitting means for transmitting or receiving means for receiving a radio signal and a battery for supplying power are commonly provided, and the wireless device including the transmitting means transmits when a predetermined event occurs. And a transmission control means for stopping the transmission means when the event does not occur and alternately repeating the operation of transmitting a radio signal during a predetermined transmission period and stopping the transmission of the radio signal during a predetermined pause period. A radio unit equipped with a receiving means, a timer means for repeatedly counting a constant intermittent reception interval, and the reception means is stopped during the counting of the intermittent reception interval by the timer means Allowed, provided with a reception control means for counting the intermittent receiving interval by the timer means starts receiving means every time to complete, the transmission period a, when the suspension periods is b, the intermittent reception interval T is T> a It is characterized in that values a and b satisfying 2a + b> T and a + 1.5b <T under the condition of > b are set in the transmission period and the pause period, respectively.

  The invention of claim 4 is characterized in that, in the invention of claim 3, the transmission period a is less than 40 seconds and the pause period b is longer than 2 seconds.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the wireless device including the transmission unit includes a fire detection unit that detects a fire, and the fire is detected by the fire detection unit. Sometimes, the transmission control means transmits a radio signal for notifying of fire detection from the transmission means, and the radio equipped with the reception means notifies when the reception means receives the radio signal for notifying of fire detection. An informing means is provided.

  According to a sixth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the wireless device including the transmission unit includes a security abnormality detection unit that detects a security-related abnormality, and the security abnormality detection unit detects an abnormality. When a signal is detected, the transmission control means transmits a radio signal for notifying of the occurrence of abnormality from the transmission means, and the radio equipped with the reception means receives the radio signal for notifying the occurrence of abnormality by the reception means. It is characterized by comprising an informing means for informing when it is done.

  The invention according to claim 7 is the invention according to any one of claims 1 to 4, wherein the wireless device including the transmission unit includes an operation input receiving unit that receives the operation input, and the operation input receiving unit receives the operation input. When received, the transmission control means causes the transmission means to transmit a radio signal for notifying the operation input acceptance, and the radio equipped with the reception means receives the radio signal for notifying the operation input acceptance by the receiving means. It is characterized by comprising an informing means for informing when it is done.

  According to the present invention, when the transmission period is a and the pause period is b, values a and b satisfying a + 2b <T and 2a + b> T are set under the condition that the intermittent reception interval T is T> a. Information transmission while reducing the power consumption of the radio by setting the values a and b such that 2a + b> T and a + 1.5b <T respectively for the transmission period and the suspension period. The delay time can be shortened.

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

  FIG. 1 is a system configuration diagram of this embodiment, and a radio transmission system is configured by a plurality of radio units TR (only two units are illustrated). In the following description, when the radio units TR are individually indicated, they are indicated as radio units TR1, TR2,..., TRn, and when collectively indicated, they are indicated as radio units TR.

  The radio TR transmits a radio signal using radio waves as a medium from the antenna 3 and receives a radio signal transmitted from another radio TR by the antenna 3, and an event generator having a microcomputer as a main component. When the occurrence of an event is notified from 4, the control unit 1 that transmits a radio signal for notifying the occurrence of the event to the other radio equipment TR from the wireless transmission / reception unit 2, and the occurrence of the event when the event occurs The event generating unit 4 that notifies the control unit 1, the notification unit 5 that notifies the event generation unit 4 that the event has been notified to the control unit 1, and a battery such as a dry battery as a power source. And a battery power supply unit 6 for supplying power.

  The radio transmission / reception unit 2 transmits / receives a radio signal using radio waves as a medium in accordance with “specific low-power radio stations” defined in Article 6 of the Radio Law Enforcement Regulations. Further, the event generation unit 4 detects suspiciously by detecting fire detection means for detecting a fire by detecting smoke, heat, flame, etc. generated by a fire or detecting a heat ray (infrared ray) emitted from a human body. Security anomaly detecting means for detecting an anomaly related to security such as an intruder, an operation input accepting means for accepting an operation input such as a push button switch. However, the fire detection means, the security abnormality detection means, and the operation input reception means are well known in the art and will not be described in detail.

  The control unit 1 realizes various functions to be described later by executing a program stored in the memory with a microcomputer. For example, when the event generation unit 4 has a fire detection means, when the event generation unit 4 notifies that the fire has been detected, the control unit 1 drives a buzzer included in the notification unit 5 to generate a notification sound. In addition to notifying the occurrence of fire by sounding (alarm sound), other wireless devices (fire detectors) TR also wirelessly transmit and receive wireless signals to notify the occurrence of fire in order to sound the sound of fire occurrence The data is transmitted from part 2. Also, when the wireless transmission / reception unit 2 receives a wireless signal transmitted from another wireless device TR (a notification of the occurrence of a fire), the control unit 1 drives a buzzer included in the notification unit 5 to generate a notification sound (alarm). Sound). That is, in the control unit 1, when the event generation unit 4 is notified of the occurrence of an event such as fire detection, human body detection, operation input reception, etc., the notification unit 5 generates a notification sound and notifies the occurrence of the event. The wireless transmission / reception unit 2 has a function of transmitting a wireless signal.

  Here, as described in the related art, “Standard Equipment for Specific Low Power Radio Station Telemeter, Telecontrol and Data Transmission (Radio Industry Association Standard ARIB STD-T67)” and “Low Power Security” In the radio equipment standard of the system radio station (Radio Industry Association Standard RCR STD-30), etc., a period during which radio signals may be transmitted continuously (transmission period a), a transmission period, and a transmission period A period during which radio signals should not be transmitted (pause period b) is defined. For example, the standard ARIB STD-T67 defines a transmission period a of 40 seconds or less and a pause period b of 2 seconds or more, and the standard RCR STD-30 defines a transmission period a of 3 seconds or less and a pause period b of 2 seconds or more. The control unit 1 transmits a radio signal in a transmission period a and a pause period b conforming to these standards.

  In order to extend the battery life of the battery power supply unit 6 as much as possible, the control unit 1 intermittently activates the radio transmission / reception unit 2 at predetermined time intervals (intermittent reception intervals T) to generate desired radio waves (other radio units TR). It is checked whether or not the wireless signal transmitted by the wireless communication device can be received. If the radio wave is not captured, the wireless transmission / reception unit 2 is immediately stopped to shift to the standby state, thereby greatly reducing the average power consumption. The radio wave reception check is performed based on the received signal strength indication signal (Receiving Signal Strength Indication: RSSI signal) output from the wireless transmission / reception unit 2 and is a DC voltage signal proportional to the magnitude of the received signal strength. The details are well known in the art and will be omitted.

By the way, as described in the prior art, when the intermittent reception operation is performed, the timing of receiving the wireless signal that should be received is delayed by the intermittent reception interval T. In order to reduce the average power consumption, it is necessary to simultaneously satisfy the conflicting condition of increasing the intermittent reception interval T to some extent. Therefore, under the condition that the intermittent reception interval T is at least longer than the transmission period a (a <T), the transmission is performed one after another (third time) when reception is not possible in the first (first) transmission period a. The values of a, b, and T that can be received in the period a were examined. That is, when the wireless signal cannot be received because the initial transmission period a ₁ overlaps the intermittent reception interval T as shown in FIG. 2, specifically, the initial pause period b ₁ coincides with the intermittent reception timing. In order to make the timing of intermittent reception coincide with the next transmission period a ₃ ,
T> b + (a + b) = a + 2b and T <(a + b) + a = 2a + b
The values of a, b, and T may be set so that For example, in the standard RCR STD-30, the transmission period a is defined as 3 seconds or less and the pause period b is defined as 2 seconds or more. Therefore, when the intermittent reception interval T is T = 8 seconds, a ≦ 3, b ≧ Under the condition (2), four straight lines b = −a / 2 + 4 (solid line A in FIG. 3) and b = −2a + 8 (FIG. 3) in the two-dimensional orthogonal coordinate system with a as the horizontal axis and b as the vertical axis. It is understood that a combination of values a and b in the region surrounded by a = 3 and b = 2 (the region hatched in FIGS. 3A and 3B) should be selected. . However, in order for the values of a and b that satisfy the above conditions to exist, the condition 6 <T <9 is necessary.

In addition, under the condition that the intermittent reception interval T is at least longer than the transmission period a (a <T), when reception is not possible in the first (first) transmission period a, one after another (fourth) The values of a, b, and T that can be received in the transmission period a are examined. That is, as shown in FIG. 2, when the first pause period b ₁ and the intermittent reception timing coincide with each other, in order to match the intermittent reception timing to the successive transmission periods a ₄ at the latest,
2T> b + 2 (a + b) = 2a + 3b and 2T <2 (a + b) + a = 3a + 2b
The values of a, b, and T may be set so that For example, in the standard ARIB STD-T67, the transmission period a is defined as 40 seconds or less and the pause period b is defined as 2 seconds or more. Therefore, when the intermittent reception interval T is T = 10 seconds, a ≦ 40, b ≧ Under the condition 2, four straight lines b = −a / 2 + 5, b = −1.5a + 10, a = 40, b = a in the two-dimensional orthogonal coordinate system having a as the horizontal axis and b as the vertical axis. It can be seen that a combination of the values of a and b in the area surrounded by 2 may be selected.

  The values of the intermittent reception interval T, the transmission period a, and the pause period b selected as described above are stored in a memory included in the control unit 1, and the control unit 1 performs the intermittent reception operation and the radio signal based on these values. If the transmission operation is executed, the delay time of information transmission (event occurrence notification) can be shortened while reducing the average power consumption of the radio equipment TR.

It is a system configuration figure showing an embodiment of the present invention. It is operation | movement explanatory drawing same as the above. (A), (b) is explanatory drawing explaining the examination result of the intermittent reception interval T in the same as the above, the transmission period a, and the idle period b.

Explanation of symbols

TR
1 Control unit (transmission control means, reception control means)
2 Radio transceiver (transmitting means, receiving means)
4 Event generator (fire detection means, security abnormality detection means, operation input reception means)
5 Notification unit 6 Battery power supply unit T Intermittent reception interval a Transmission period b Rest period

Claims (7)

A wireless transmission system comprising a plurality of wireless devices and transmitting wireless signals between the plurality of wireless devices,
Each radio unit includes at least one of a transmission unit that transmits a radio signal or a reception unit that receives a radio signal, and a battery for power supply in common.
The wireless device including the transmission unit activates the transmission unit when a predetermined event occurs, and alternately performs an operation of transmitting a radio signal during a predetermined transmission period and halting transmission of the radio signal during a predetermined pause period. Repetitively and comprising a transmission control means for stopping the transmission means when the event has not occurred,
The wireless device having the receiving means stops the receiving means during the counting of the intermittent reception interval by the timer means that repeatedly counts a certain intermittent reception interval, and completes the counting of the intermittent reception interval by the timer means. And receiving control means for starting the receiving means,
When the transmission period is a and the pause period is b, the values a and b satisfying a + 2b <T and 2a + b> T under the condition that the intermittent reception interval T is T> a > b are set as the transmission period and the pause period. A wireless transmission system characterized in that each is set.   The wireless transmission system according to claim 1, wherein the transmission period a is less than 3 seconds and the pause period b is longer than 2 seconds. A wireless transmission system comprising a plurality of wireless devices and transmitting wireless signals between the plurality of wireless devices,
Each radio unit includes at least one of a transmission unit that transmits a radio signal or a reception unit that receives a radio signal, and a battery for power supply in common.
The wireless device including the transmission unit activates the transmission unit when a predetermined event occurs, and alternately performs an operation of transmitting a radio signal during a predetermined transmission period and halting transmission of the radio signal during a predetermined pause period. Repetitively and comprising a transmission control means for stopping the transmission means when the event has not occurred,
The wireless device having the receiving means stops the receiving means during the counting of the intermittent reception interval by the timer means that repeatedly counts a certain intermittent reception interval, and completes the counting of the intermittent reception interval by the timer means. And receiving control means for starting the receiving means,
When the transmission period is a and the pause period is b, values a and b satisfying 2a + b> T and a + 1.5b <T under the condition that the intermittent reception interval T is T> a > b. A wireless transmission system characterized in that each period is set.   4. The wireless transmission system according to claim 3, wherein the transmission period a is less than 40 seconds and the pause period b is longer than 2 seconds. The wireless device including the transmission means includes a fire detection means for detecting a fire, and when the fire is detected by the fire detection means, the transmission control means transmits a wireless signal for notifying the fire detection from the transmission means. Become
5. The radio device comprising the receiving means comprises an informing means for informing when a radio signal for notifying of fire detection is received by the receiving means. 6. Wireless transmission system. The wireless device having the transmission means includes a security abnormality detection means for detecting an abnormality related to security, and transmits a wireless signal for notifying the occurrence of abnormality by the transmission control means when the abnormality is detected by the security abnormality detection means. Means to send it,
5. The radio device comprising the receiving means comprises an informing means for informing when a radio signal for notifying the occurrence of an abnormality is received by the receiving means. 6. Wireless transmission system. A wireless device including a transmission unit includes an operation input reception unit that receives an operation input, and when the operation input is received by the operation input reception unit, a transmission unit transmits a radio signal for notifying the operation input reception by the transmission control unit Let me send
The wireless device including the receiving unit includes a notifying unit that notifies when a receiving unit receives a radio signal for notifying operation input reception. Wireless transmission system.

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