JPH04309021A - Radio communication system - Google Patents

Abstract

PURPOSE:To attain quick and sure communication by all slave stations. CONSTITUTION:Communication with a master station 1 is implemented by using a 1st carrier frequency f1 by a 1st class slave station 2 in which communication is frequently implemented. Communication with the master station 1 is implemented by using a 2nd carrier frequency f2 by a 2nd class slave station 2 in which communication is rarely implemented. The master station 1 receives a signal of the 2nd carrier frequency f2 intermittently only for a short period while the master station 1 receives a signal of the 1st carrier frequency f1 to confirm whether or not a data transmission request of the 2nd class slave station 2 is in existence. When the slave station 2 of the 2nd class sends a data, the station 2 sends an acquisition signal to bring the master station 1 into a data receptible state.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication method used in a security system for transmitting sensor information and the like.

0002

[Background Art] A security system receives a plurality of slave stations to which disaster prevention and crime prevention devices such as disaster prevention sensors and crime prevention sensors are connected, and signals indicating the operating status of each disaster prevention and crime prevention device transmitted from these slave stations. Some devices include one master station that monitors the operating status of each disaster prevention and security device, and perform unidirectional wireless communication from the slave station to the master station.

0003

[Problem to be Solved by the Invention] However, since the carrier frequency for wireless communication from the slave station to the master station in this security system is fixed to one frequency, the transmission signals from each slave station collide, resulting in communication problems. There was a problem that made it impossible. In other words, in a security system equipped with disaster prevention and crime prevention devices such as this type of disaster prevention sensor and crime prevention sensor, for example, an intrusion warning sensor as a crime prevention sensor is frequently used in response to the opening and closing of doors and windows when family members are at home. If there is a slave station that communicates with the master station,
For example, if a fire is detected by a fire sensor,
Alternatively, if the emergency push button is pressed, the transmission signal of the slave station mentioned above collides with the transmission signal of the slave station connected to the fire sensor, etc., making communication impossible, resulting in delayed or missed fire alarms. There was a risk that this would occur.

The present invention has been made in view of the above points, and its purpose is to provide a wireless communication system in which all slave stations can communicate quickly and reliably.

[0005]

[Means for Solving the Problems] In order to achieve the above object, in the present invention, a first type slave station with which communication is frequently performed communicates with a master station using a first carrier frequency, and , the second type slave station, which rarely communicates, communicates with the master station using the second carrier frequency, and only intermittently during a short period of time while the master station receives the signal of the first carrier frequency. The second type of slave station receives the signal of the second carrier frequency and checks whether there is a data transmission request, and when the second type of slave station sends data to the master station, the second type of slave station A capture signal is being sent to enable data reception.

[0006]

[Operation] By configuring the present invention as described above,
By making the carrier frequencies different for slave stations that frequently communicate with the master station and slave stations that rarely communicate, the master station transmits data to the slave stations that rarely communicate. By checking whether or not there is a transmission request, it is possible to ensure that a slave station that frequently communicates has a sufficient communication period, and when transmitting data from a slave station that rarely communicates, it is possible to This system transmits a signal to put the master station in a state where it can receive data, so that even slave stations that rarely communicate can communicate reliably.

[0007]

Embodiment FIGS. 1 to 4 show an embodiment of the present invention. FIG. 2 shows a security system as an example to which the present invention is applied. In this security system, disaster prevention and crime prevention devices such as a fire sensor S1 as a disaster prevention sensor, a gas leak alarm sensor S2 and an emergency push button S3, and an intrusion warning sensor S4 as a crime prevention sensor, or an emergency notification device S5 are connected. The slave stations 2 and the sensors S receive transmission signals indicating the operating states (abnormality sensing states) of the various sensors S transmitted wirelessly from these slave stations 2.
It consists of one master station (controller) 1 that monitors the operating status of the controller. Note that FIG. 2 shows a case where the slave station 2 is integrated into each sensor S. The master station 1 includes a display section 1a that individually displays the operating status of each sensor S, and issues an alarm when an abnormality occurs. In addition, in this master station 1, telephone 9
is connected so that abnormalities can be reported by telephone using this telephone 9. In addition, some devices have a function that automatically contacts family members at their workplaces etc. in the event of an abnormality through a telephone line.

FIG. 4 shows an example of the configuration of the slave station 2.
Oscillator 211, frequency divider 221, phase comparator 231
, a low-pass filter 241, a VCO 251, a prescaler 261, and a programmable frequency divider 271. The carrier frequency can be variably set to an appropriate frequency. The data of the sensor S is given from the CPU 28 to the VCO 251 via the splatter filter 29 as a modulation signal indicating the data of the sensor S.
CO251 modulates the carrier wave, preamplifier 30,
It is transmitted from an antenna 33 via a power amplifier 31 and a bandpass filter 32. Note that the slave station 2 has a function of adjusting the power supplied from the power supply circuit 36 to the transmitting circuit under the control of the CPU 28 to adjust the transmission power.

FIG. 3 shows an example of the configuration of the master station 1.
The receiving circuit of the master station 1 also uses a PLL synthesizer circuit a2 having the same configuration as the slave station 2 side, and the signal received by the antenna 11 is passed through the bandpass filter 12 and the RF amplifier 1.
3 to the first mixer 141, the output of the PLL synthesizer circuit a2 is given to the first mixer 141 as the first local oscillation signal, and the first mixer 141 lowers the frequency of the received signal to the first intermediate frequency. , this first intermediate frequency is passed through the bandpass filter 15 and the IF amplifier 16.
1 to the second mixer 142 via oscillator 1
The second intermediate frequency is mixed with the second local oscillation signal output from 7 and further lowered to a second intermediate frequency, and the second intermediate frequency is amplified by an IF amplifier 162, the output is demodulated by a demodulator 18, and detected via a low-pass filter 19. I am trying to get the output. This detection output is input to the control CPU 20, where it is determined whether a fire has occurred or the presence of an intruder, and an abnormality notification is performed based on this determination. In this master station 1, the reception frequency can be changed as appropriate by changing the division ratio of the programmable frequency divider 272.

Among the slave stations 2, the slave station 2 that frequently communicates with the master station 1 is referred to as a first type slave station 2, and the first type slave station 2 is shown in FIG. As shown in the figure, communication is performed with the master station 1 using the first carrier frequency f1. The first type of slave station 2 is, for example, a slave station 2 to which an intrusion warning sensor S4 is connected. A slave station 2 that rarely communicates with the master station 1 is defined as a second type slave station 2, and the second slave station 2 communicates with the master station 1 using the second carrier frequency f2. Communicate between.

As shown in FIG. 1(b), the master station 1 intermittently receives the signal of the second carrier frequency f2 only for a very short period of time while receiving the signal of the first carrier frequency f1. That is, the period for receiving the signal from the first type slave station 2 is T1.
and the period for receiving the signal from the second type slave station 2 is T.
2, T1 >> T2, and during period T2, it is checked whether there is a data transmission request from fire sensor S1 or the like. Therefore, master station 1
Normally, data is sent only from the slave station 2 connected to the intrusion warning sensor S4, which communicates frequently, and other slave stations 2 that communicate less frequently only receive data transmission requests. It will operate as follows.

[0012] When transmitting data from the slave station 2, which has a low communication frequency, to the master station 1, the slave station 2 puts the master station 1 in a state where it can receive data before transmitting the data. Send acquisition signal. Specifically, the period for receiving the second carrier frequency f2 of the master station 1 using the acquisition signal is set to be longer than at least the period T1 (the intermittent reception state may be changed to the continuous reception state), and then It sends data. In this way, data from the second type slave station 2 can also be reliably transmitted to the master station 1. In addition, in FIG. 1(c), the acquisition signal is transmitted at the point indicated by the arrow, and the master station 1
is ready to receive data.

[0013]

Effects of the Invention As described above, the present invention provides that the first type slave station with which communication is frequently performed communicates with the master station using the first carrier frequency, and the second type slave station with which communication is rare. The slave station is the second
The master station communicates with the master station using the carrier frequency of The second type of slave station checks whether there is a request to send data to the slave station, and when the second type slave station sends data to the master station, it sends a capture signal that makes the master station ready to receive data. Since the carrier frequencies are different for slave stations that frequently communicate with the master station and slave stations that rarely communicate with each other, collisions of transmitted signals do not occur.
In addition, since the master station normally checks whether there is a data transmission request for a slave station with which communication is rare, it is possible to ensure that the communication period is sufficient for the slave stations that frequently communicate with the slave station, and that When transmitting data from the station, the slave station transmits a capture signal to put the master station in a state where it can receive data, so even slave stations that rarely communicate can reliably communicate.

[Brief explanation of drawings]

FIG. 1(a) is an explanatory diagram showing a schematic configuration of an embodiment of the present invention. (b) is an explanatory diagram of the operation during normal operation same as above. (c) is an explanatory diagram of the operation when receiving data from the second type slave station same as above.

FIG. 2 is a configuration diagram of a security system including the above.

FIG. 3 is a circuit configuration diagram of a master station.

FIG. 4 is a circuit configuration diagram of a slave station.

[Explanation of symbols]

1. Master station 2.Slave station S sensor

Claims (1)

[Claims] [Claim 1] Disaster prevention such as disaster prevention sensors and crime prevention sensors,
It is equipped with a plurality of slave stations to which crime prevention devices are connected, and a master station that receives signals indicating the operational status of each disaster prevention and crime prevention device transmitted from these slave stations and monitors the operational status of each disaster prevention and crime prevention device. In a wireless communication system in which communication is performed unidirectionally by radio from a slave station to a master station, a first type slave station with which communication is frequently performed communicates with the master station using a first carrier frequency, and The second type of slave station, which rarely communicates, communicates with the master station using the second carrier frequency, and only communicates with the master station intermittently for a short period while the master station receives the signal on the first carrier frequency. When the second type slave station receives the signal of the second carrier frequency and confirms whether there is a data transmission request, the second type slave station transmits data to the master station. A wireless communication method characterized by transmitting a capture signal to enable reception.