JP2001160189A - Radio transmitter for security information and radio transmitting/receiving system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make surely receivable a security signal with a simple configuration by avoiding the interference of a transmitting signal in a security system provided with plural transmitters. SOLUTION: By controlling the transmission cycle of security information at random, the mutual collision of plural transmitting signals is avoided. Concerning the transmission cycle, the delay time is controlled at random corresponding to random time generated by using the free-run counter of (n) bits of a CPU. During the operation of the CPU, the free-run counter performs counting-up at a speed of L/ϕ. When the security information from security equipment is detected, the value of the free-run counter of the CPU is read, a mask counter value is provided by masking that value with predetermined bits and a random time interval T is provided by a prescribed calculation expression. By setting this random time interval T to a delay timer, random delay time is generated and the random cyclic transmission of the security information is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a security information wireless transmission device and a wireless transmission / reception system,
The present invention relates to a security information wireless transmission device and a wireless transmission / reception system applicable to a wireless security monitoring system using wireless communication, a wireless meter reading system, a wireless medical telemeter, and the like.

[0002]

2. Description of the Related Art For example, there is a security system in which security information for the purpose of a fire alarm, an approach alarm, or an emergency call for an elderly person living alone is transmitted to a receiving device such as a security monitoring center by a wireless transmitting device.
In such a security system, when a case occurs in which a plurality of transmitters repeatedly transmit security information at the same time, a plurality of transmission signals interfere with each other, making it difficult for the receiver to receive the security information.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and avoids interference of transmission signals in a security system including a plurality of transmitters, and ensures security with a simple configuration. It is an object of the present invention to provide a security wireless transmission device and a wireless transmission / reception system capable of receiving information.

[0004]

According to a first aspect of the present invention, in a security information wireless transmitter for wirelessly transmitting security information generated from a security device to a wireless receiver, an n-bit free-run counter of a CPU is provided. The method is characterized in that a random time interval is repeatedly generated using the information, and the transmission of security information is set during the random time interval.

According to a second aspect of the present invention, in the first aspect of the invention, upon detecting security information from a security device, a counter value of a free-run counter of the CPU is read, and the read counter value is determined in advance. A bit mask is applied to obtain a mask counter value, a predetermined calculation process is performed on the mask counter value to generate a random time interval, and the random time interval is set as a delay timer when the security information is repeatedly transmitted. Thus, the transmission cycle of the security information is set at random.

According to a third aspect of the present invention, there is provided one wireless receiver,
In a security information wireless transmission / reception system having a plurality of wireless transmitters for transmitting security information, by using the security information wireless transmitter according to claim 1 or 2 as the wireless transmitter, security information from the wireless transmitter is obtained. Is different every time one wireless transmitter performs a transmitting operation and for each of the plurality of wireless transmitters.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram for explaining an outline of an operation of transmitting security information in a wireless transmission apparatus for security information according to the present invention. After detecting the security information, the transmitter calculates a delay time until the next transmission by a random time calculation process. Then, it waits in the wait processing until the time count of the calculated delay time, and after the timeout, transmits once. If there is no input of the stop process, the process returns to the random time process again, and the above operation is repeated.

FIG. 2 is a diagram showing a configuration of a transmission signal transmitted by the security information wireless transmission device of the present invention.
Is the delay time. According to the present invention, a collision between a plurality of transmission signals is avoided by controlling the transmission cycle of security information to be random. In the transmission cycle, a delay time T is set by a random time interval generated by using a 16-bit free-run counter of the CPU, thereby controlling the security information transmission cycle to be random. The free-run counter counts up at a speed of 1 / φ while the CPU is operating. In the present invention, the free-run counter is not limited to 16 bits, and an n-bit free-run counter can be used if necessary.

At the timing when the random time calculation process in FIG. 1 is performed, the value of the free-run counter of the CPU is read, a predetermined bit is masked by the read value to obtain a mask counter value A, and the random time interval T Is calculated by the following equation (1). T (sec) = A × 1 (sec) +2.2 (sec) (1) The random time interval T is generated by setting the obtained random time interval T in the delay timer. With this method, random periodic transmission can be realized.

FIG. 3 is a diagram for explaining the reception stability obtained by random periodic transmission by the security information transmitter of the present invention. Since the security information transmitted from the plurality of transmitters (transmitters 1 and 2) by the random period transmission as described above changes its transmission period for each transmission, for example, as shown in FIG. Even if the first transmission signal transmitted from the transmitter 2 collides with the transmission signal transmitted from the transmitter 1, the collision can be avoided by the second or multiple transmissions from the transmitter 2, and both transmissions can be performed. A signal is received at the receiver.

FIG. 4 is a flowchart showing a software control processing operation for transmitting security information in the security information wireless transmission apparatus of the present invention. First, the system state is initialized (step S1), and security information is detected (step S2). If security information is detected, a free-run counter is read (step S3). Then, a partial bit mask process of the read counter is performed (step S4), and a random time interval is calculated from the obtained value (step S4).
5). Then, a delay timer is set based on the obtained random time interval (step S6), and if a timeout occurs, a transmission process is executed (steps S7 to S8).
If there is a transmission stop instruction in step S9, the flow returns to step S2 to detect security information. If there is no transmission stop instruction, the flow returns to step S3 to read the free counter and continue the security information transmission processing.

[0012]

As described above, according to the present invention,
Since the random period transmission is realized using the free-run counter of the CPU, interference of security signals transmitted from a plurality of transmitters can be avoided with a simple configuration,
This makes it possible to build a highly reliable security system.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a transmission operation in a security information wireless transmission device according to the present invention.

FIG. 2 is a diagram showing a configuration of a transmission signal transmitted by the security information wireless transmission device of the present invention.

FIG. 3 is a diagram for explaining reception stability obtained by random periodic transmission by the security information wireless transmission device of the present invention.

FIG. 4 is a flowchart showing a software control processing operation for transmitting security information in the security information wireless transmission device of the present invention.

Continued on the front page F term (reference) 5C087 BB18 BB58 DD03 EE02 EE07 GG30 GG38 5K060 BB05 CC04 DD01 DD09 HH32 HH34

Claims (3)

[Claims] 1. A security information wireless transmitter for wirelessly transmitting security information generated from a security device to a wireless receiver, wherein a random time interval is repeatedly generated using an n-bit free-run counter of a CPU, A security information wireless transmitter, wherein transmission of security information is set during the random time interval. 2. The security information wireless transmitter according to claim 1, wherein when security information from a security device is detected, a counter value of a free-run counter of the CPU is read, and the read counter value is determined in advance. Applying a bit mask to obtain a mask counter value, performing a predetermined calculation process on the mask counter value to generate a random time interval, and using the random time interval as a delay timer when repeatedly transmitting the security information. A security information wireless transmitter characterized in that, by setting, a transmission cycle of the security information is set at random. 3. The security information wireless transmitter according to claim 1, wherein the security information wireless transmission / reception system includes one wireless receiver and a plurality of wireless transmitters for transmitting security information. The security information transmission cycle of the security information from the wireless transmitter is different every time one wireless transmitter performs a transmission operation and for each of the plurality of wireless transmitters. Transmission / reception system.