JPH0722280B2 - Wireless paging system - Google Patents

Description

TECHNICAL FIELD The present invention relates to a wireless paging system, and more particularly to a transmission / reception system thereof.

[Conventional technology]

The wireless paging system is a system for wirelessly transmitting an individual call message to a specific limited area such as a company, a hospital, and a factory.

In this system, the transmitter is installed on the ceiling of the room, etc., and the receiver is carried in the chest pocket of the recipient (pager) who receives the call. This receiver receives a paging signal composed of an individual identification code (ID code) and message data transmitted from a transmitter, generates a ringing tone by a buzzer, or displays a message on a display.

In such wireless paging, the level of the receiving side greatly changes due to the influence of fading and the movement of the receiving side, so that an error is likely to occur in the received data.

Therefore, in order to reduce the error rate, a signal in which a personal identification code and message data are consecutive is set as one block, this block is retransmitted multiple times by the transmitting side, and the receiving side averages the multiple blocks. A method of increasing the reception sensitivity and expanding the service area by improving the S / N ratio without increasing the transmission level has been conventionally proposed.

[Problems to be Solved by the Invention]

However, when the signal block in which the personal identification code and the message data are consecutive is retransmitted multiple times by averaging, the number of data included in one block is several.
Since it is 100 bits, if the number of retransmissions is 100 times, for example, the total number of bits will be tens of thousands of bits, and the time required to call a destination and send a message will be very long and the battery of the receiver will be drained. However, there is a problem in that the waiting time in other receivers becomes longer by that much.

To reduce this transmission time, it is desirable to increase the data transmission rate. However, increasing the data transmission rate increases the occupied frequency bandwidth of the signal, so it is necessary to widen the bandwidth of the band filter of the receiver, but with this, the external noise that enters the receiver becomes large. / N ratio gets worse.

Bandwidth is often regulated by legal regulations.

The present invention has been made to solve such conventional problems, and an object of the present invention is to provide a wireless paging system capable of reducing the waiting time for retransmission and reducing battery consumption.

[Means for Solving the Problems]

According to the present invention, a transmitter that repeatedly transmits data to be transmitted a predetermined number of times, and a receiver that includes an averaging means and that receives a repetitive signal transmitted from the transmitter and averages and reproduces the repetitive signal. In the provided wireless paging system, the receiver includes error detection means for extracting the error detection code included in the data for each averaging and stopping the averaging operation for the averaging means when it is determined that there is no error. It is characterized by that.

[Work]

The data repeatedly transmitted includes an error detection code such as a CRC code. This error detection code is detected by the error detection means, but when no error is detected, a signal is issued to the averaging means to stop the averaging operation, so that averaging is not performed thereafter, and operation such as display is performed. As a result, the power consumption in the receiver is reduced due to the shift to (1) and the waiting time in other receivers is also reduced because the data occupation time due to the retransmission is also reduced.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of a wireless paging system according to the present invention. According to the figure, the transmitter 10 is connected to a keyboard 1 for inputting an ID code, which is a paging-specific identification code for paging, and a message, which is the content of transmission, and the output of the keyboard 1 is in the transmitter 10. Is input to the continuous reproduction data generating circuit 2.

FIG. 2 shows the data output from the continuous reproduction data generating circuit 2. For example, a 10-bit preamble indicating that transmission is started is followed by a 16-bit ID code, for example, a 100-bit message. , A data block of a cycle T composed of a CRC (Cyclic Redundancy Check) code for error detection is retransmitted 100 times.

The data block generated by the continuous reproduction data generation circuit 2 in this way is, for example, the carrier frequency 400 MHz by the modulation circuit 3.
It is FM-modulated by and is transmitted to the air through the transmission circuit 4 including the antenna.

The transmitted signal is received by the receiving circuit 11 having the antenna in the receiver 20 and demodulated by the demodulating circuit 12,
The averaging processing circuit 13 performs averaging described later. The averaging result is the message decoding circuit 14
And the ID code are input to the determination circuit 17, respectively. ID
The code discrimination circuit 17 selectively extracts the ID code portion of the signal obtained by the processing in the averaging processing circuit 13 and compares it with the ID code stored in the ROM provided in the ID code discrimination circuit. To do. When the two match according to this comparison, the buzzer drive circuit 18 sounds the buzzer 19 to notify the receiver that the message has been sent. Further, a drive signal is sent from the ID code discrimination circuit to the display drive circuit 15 to enable display on the display unit 16. The message data decoded by the message decoding circuit 14 is sent to the display driving circuit 15 and the message is displayed on the display 16.

On the other hand, when the contents of the ID code portion of the received signal and the stored ID code do not match, the ID code determination circuit 17 generates a mismatch signal to the buzzer drive circuit 18 and the display drive circuit 15. Therefore, the buzzer 19 does not ring and the indicator
It is not displayed on 16.

FIG. 3 is a block diagram showing a detailed configuration of the averaging processing circuit 13. The signal e1 input to the input terminal 31 is stored in the addition circuit 32 after being delayed by one block by one block delay 33. The output is given to the switch 35 and fed back to the other side input of the adding circuit 32. The output of the 1-block delay 33 is set to 0 level before the input is added. The signal e1 is also input to the level conversion start detection circuit 34, the output of which is supplied to actuate the switch 35. The output side of the switch 25 is given to the decoder 37 via the 1 / n multiplication circuit 36, and the output signal is taken out from the output terminal 38. Therefore, the received data block is added to the previous data block, and this value is divided by the number of additions, so that the data is averaged. For example, the S / N ratio improved by averaging n times is 3lo based on the information theory.
Since it is g ₂ n (db), if the number of retransmissions n = 100, the S / N ratio is improved by about 20 dB, and the service area is expanded by about 3 times.

Further, in this embodiment, the averaging processing circuit 13
There is provided an error detection circuit 21 for receiving the output of the above. Here, the CRC code in the above-mentioned data is checked. When there is no error as a result of this check, the error detection circuit
21 outputs a signal for stopping the averaging to the averaging processing circuit 13. This signal activates the level conversion start detection circuit 34 in the averaging processing circuit 13, stops addition for each block, and switches the switch 35 to take out the averaging result.

As a result, the averaging is completed,
The above-described operations of calling the buzzer and displaying are performed. Therefore, when the reception state is good and there is no error, almost no averaging is performed and the operation immediately shifts to the buzzer calling and display operation and becomes the operation stop state, so that no unnecessary power is consumed. Also, in other receivers, the time occupied for data transmission is reduced and the waiting time is reduced.

Although the CRC code is used as the error detection code in the above embodiments, another error detection code such as parity may be used.

Further, in the embodiment, the system in which the electric wave is used for transmission is shown, but the present invention can be similarly applied to a system for transmitting by optical wireless.

〔The invention's effect〕

As described above, according to the present invention, the error detection code included in the data is extracted every time the received data is averaged, and when it is determined that there is no error, the error that causes the averaging means to stop the averaging operation is performed. Since the detection means is provided, when it is determined that there is no error, the process immediately shifts to calling or display, so power consumption can be significantly reduced by not performing extra operations. . In addition, the waiting time can be reduced because the time occupied for data transmission is reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a wireless paging system according to the present invention, FIG. 2 is an explanatory diagram showing a configuration of a signal to be transmitted, and FIG. 3 is a block diagram showing a configuration of an averaging processing circuit. 1 ... keyboard, 2 ... continuously retransmitted data generator, 3
...... Modulation circuit, 4 …… Transmission circuit, 10 …… Transmitter, 11 ……
Reception circuit, 12 ... Demodulation circuit, 13 ... Averaging processing circuit, 14 ... Message decoding circuit, 15 ... Display drive circuit, 16 ... Display, 17 ... ID code discrimination circuit, 18 ... Buzzer drive Circuit, 19 …… Buzzer, 20 …… Receiver, 21 …… Error detector, 32 …… Adder, 33 …… 1 block delay circuit, 34 ……
Level conversion start detection circuit, 35 …… switch, 36 …… 1 / n
Multiplier circuit, 37 ... Decoder.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-2439 (JP, A) JP-A-62-172830 (JP, A) JP-A-1-174129 (JP, A)

Claims (1)

[Claims] 1. A transmitter for repeatedly transmitting data to be transmitted a predetermined number of times, and a receiver including an averaging means for receiving a repeated signal transmitted from the transmitter and averaging the reproduced signal to reproduce the repeated signal. In the wireless paging system provided with, the receiver extracts an error detection code included in the data for each averaging, and an error that causes the averaging means to stop the averaging operation when it is determined that there is no error. A wireless paging system comprising a detecting means.