JPH08102684A - Radio communication system - Google Patents

Abstract

PURPOSE: To reduce power consumption by detecting a synchroning signal within regulated time, executing receiving operation, and when the synchroning signal is not detected, setting up a stand-by state. CONSTITUTION: At the time of detecting gas leakage, a detector transmits an alarm signal to a transmitter, the alarm signal is sent from the transmitter to a receiver 9 by a radio signal and a gas meter microcomputer 11 interrupts gas supply. Since voltage is intermittently impressed from a power supply 23 to a receiving part 13, a carrier is sensed by the receiving part 13, and if no carrier exists, the receiving part 13 is turned to a stand-by state. At the time of detecting a carrier, a CPU 17 detects a synchroning signal corresponding to a signal sent from the receiving part 13, and when no synchronizing signal is detected, whether the regulated time has elapsed or not is judged. When the regulated time has not elapsed, the receiving part 13 is returned to the stand-by state to sense a carrier again. When the regulated time has elapsed, the receiving part 13 executes the sense of a carrier as it is.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power saving type wireless communication system.

[0002]

2. Description of the Related Art Recently, a detector for gas leak or the like is installed in a room, a wireless transmitter (transmitter) is installed in this detector, and a wireless receiver (receiver) is installed in an outdoor gas microcomputer meter. A wireless communication system has been developed in which, when a gas leak is detected by a detector, the gas microcomputer meter is notified of the gas leak by wireless communication, and the gas microcomputer meter shuts off the gas.

In a receiver of such a wireless communication system, in order to keep power consumption low, carrier sensing is performed intermittently, and when the carrier sense is performed and the communication is addressed to itself, the receiving operation is started. .

FIG. 6A shows the voltage supplied to the receiving section of the receiver when the carrier sense is intermittently performed. If the communication was addressed to you, start receiving operation,
The receiving operation is performed until the specified timeout time.

[0005]

However, since the receiving operation is performed for the time-out period, the time-out receiving operation can be performed even when there is another interfering radio wave (radio wave such as noise) in the target frequency band. will have to go. FIG. 6B shows a case where the jamming radio wave is detected and the timeout time T1 reception operation is performed.

As described above, since the receiving operation is performed even with respect to the interference radio wave, there is a problem that wasteful power consumption occurs, and in the case of a battery power source such as a battery, the operable time of the receiver is reduced. .

The present invention has been made in view of the above problems, and an object thereof is to provide a wireless communication system capable of reducing power consumption without entering a receiving operation even in the presence of an interfering radio wave or the like. Especially.

[0008]

In order to achieve the above-mentioned object, the present invention is a wireless communication system for performing wireless communication between a transmitter and a receiver, wherein the transmitter is at least synchronized when an alarm occurs. A transmission signal including a signal and an alarm signal is wirelessly transmitted, and the receiver performs carrier sensing intermittently, and when a carrier is detected, the synchronization signal is detected within a specified time, and the synchronization signal is detected. The wireless communication system is characterized in that the reception operation is started when the synchronization signal is received, and the standby state is entered when the synchronization signal is not detected.

[0009]

According to the present invention, the receiver intermittently carries out carrier sensing, detects a carrier, detects the synchronizing signal within a specified time, and when the synchronizing signal is detected, the receiver enters the receiving operation. If the sync signal is not detected, the standby state is entered.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of a wireless communication system according to an embodiment of the present invention. A detector 1 for detecting a gas leak or the like is installed indoors, and a wireless transmitter (transmitter) 3 having an antenna 5 is connected to the detector 1. For example, a receiver 9 having an antenna 7 is connected to a gas microcomputer meter 11 installed outdoors.

When the detector 1 detects a gas leak or the like, it sends an alarm signal to the transmitter 3, the alarm signal is sent from the transmitter 3 to the receiver 9 as a radio signal, and the gas microcomputer meter 11 shuts off the gas. .

FIG. 2 is a schematic block diagram of the receiver 9. The receiver 9 includes a receiver 13 and a wireless communication interface 1.
5, a CPU 17, a memory 19, a wired communication interface 21, and a power supply 23.

The receiving section 13 detects the signal sent from the antenna 7 and receives it. Wireless communication interface 1
Reference numeral 5 serves as an interface between the receiving unit 13 and the CPU 17. The CPU 17 processes the signal sent from the receiving unit 13. The wired communication interface 21 serves as an interface between the CPU 17 and the gas microcomputer meter 11.
The power supply 23 constantly supplies power to the CPU 17 and intermittently supplies power to the receiving unit 13. Therefore, the carrier sense is intermittently performed in the receiving unit 13. FIG.
FIG. 4 is a format diagram of a signal sent from the transmitter 3. This signal is a sync signal 31, an ID 33, and an alarm signal 3.
Have 5. The synchronization signal 31 is inserted by the transmitter 3. ID33 is the ID number of the receiver 9 and the alarm signal 3
Reference numeral 5 is an alarm signal sent from the detector 1. Sync signal 3
The time for sending 1, ID 33, and alarm signal 35 is T. The transmitter repeatedly sends the synchronization signal ID and the alarm signal radio wave for a certain period of time.

Next, the receiving operation of the receiver 9 will be described with reference to FIGS. FIG. 4 is a flowchart showing the operation of the receiver 9, and FIG. 5 shows the voltage supplied to the receiver 13. Since voltage is intermittently supplied from the power supply 23 to the receiving unit 13, carrier sensing is performed by the receiving unit 13 (step 401). If no carrier is present (step 402), the receiving unit 13 enters a standby state. (Step 403). Then, carrier sense is performed again (step 401).

FIG. 5A shows the voltage supplied to the receiver 13 when the carrier sense is intermittently performed in this way.

When the carrier can be detected in step 402, the CPU 17 detects the sync signal from the signal sent from the receiver 13 (step 404). When the sync signal cannot be detected (step 405), the specified time T is reached. Is determined (step 406). The specified time T is the same as the time for sending out the synchronization signal 31, the ID 33, and the alarm signal 35 shown in FIG. If the prescribed time T has not elapsed, the process returns to the standby state (step 40
3) Then, perform carrier sense again. If the specified time T has passed in step 406, carrier sensing is performed as it is.

FIG. 5B shows the voltage supplied to the receiving unit 13 when the receiving unit 13 detects an interfering radio wave. As shown in FIG. 5 (b), when an interfering radio wave is detected,
Although the voltage is supplied to the receiving unit 13 within the specified time T, the voltage is not supplied after the specified time T, and the standby state is entered.
Therefore, the receiving unit 13 is in a standby state before the conventional time-out period T1 and power consumption can be reduced.

In FIG. 4, when the synchronization signal can be detected in step 405 of FIG. 4, the receiver 9 performs the original receiving operation until the reception is completed (steps 407 and 408).
When the reception is completed, it enters the standby state (step 403),
After that, carrier sense is performed again (step 401).

FIG. 5C shows the case where a sync signal is detected.
It indicates the voltage supplied to the receiving unit 13, and the specified time T
When the sync signal is detected, the reception operation is started from the time when the sync signal is detected.

As described above, in this embodiment, when the interfering radio wave is received, the synchronizing signal 31 is detected only for the specified time, so that the power consumption can be reduced as compared with the conventional case, and the receiver When 9 uses a battery or the like as a power source, the operable time of the receiver 9 can be lengthened.

In the above-described embodiment, the specified time T is the time for transmitting the synchronization signal 31, ID 33 and alarm signal 35 from the transmitter 3. This is a case where the transmitter 3 and the receiver 9 operate independently of each other, and when the transmitter 3 and the receiver 9 start operating at the same time, the synchronization signal 31 is transmitted for a specified time T. It may be time.

[0022]

As described above in detail, according to the present invention, it is possible to reduce the power consumption without entering the receiving operation even if there is an interfering radio wave.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a wireless communication system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of a receiver 9.

FIG. 3 is a format diagram of a signal transmitted from the transmitter 3.

FIG. 4 is a flowchart showing the operation of the receiver 9.

FIG. 5 is a diagram showing a voltage supplied to a receiver 13.

FIG. 6 is a diagram showing a voltage supplied to a receiver of a conventional receiver.

[Explanation of symbols]

 1 ………… Sensor 3 ………… Transmitter 9 ………… Receiver 11 ………… Gas microcomputer meter 13 ………… Receiver 17 ………… CPU 23 ……… Power supply 31 ……… Synchronization signal

Claims (3)

[Claims] 1. A wireless communication system for performing wireless communication between a transmitter and a receiver, wherein the transmitter wirelessly transmits a transmission signal having at least a synchronization signal and an alarm signal during an alarm, and the reception The machine intermittently carries out carrier sensing, and when it detects a carrier, it detects the synchronization signal within a specified time, and if the synchronization signal is detected, it enters the receiving operation, and if the synchronization signal is not detected, it waits. A wireless communication system characterized by entering a state. 2. The wireless communication system according to claim 1, wherein the specified time is a time for transmitting the transmission signal. 3. The wireless communication according to claim 1, wherein when the transmitter and the receiver start operating at the same time, the specified time is a time for transmitting the synchronization signal. system.