JPH01181250A - Radio paging system - Google Patents

Abstract

PURPOSE:To reduce the power consumption by extracting a error detection code included in a data for each averaging of a reception data and stopping the averaging processing to an averaging means at a point of time when it is discriminated that no error exists. CONSTITUTION:A sent signal is received by a reception circuit 11 provided with an antenna in a receiver 20, demodulated by a demodulation circuit 12 and subject to averaging processing by an averaging processing circuit 13. An error detection circuit 21 receiving an output of the averaging processing circuit 13 checks a CRC code in the data and outputs a signal stopping averaging to the averaging processing circuit 13 when no error exists. When the reception state is excellent and there exists no error, since the averaging is not almost caused but the buzzer call and display state is transited and the operation is stopped, no waste power is consumed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wireless paging system, and particularly to its transmission and reception method.

[Conventional technology]

A wireless paging system is a system that wirelessly transmits personal paging messages within a specific, limited area such as a company, hospital, or factory.

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

In such wireless paging, errors are likely to occur in received data because the level on the receiving side changes greatly due to the movement of the receiving side or the influence of fading.

Therefore, in order to reduce the error rate, the transmitting side retransmits a signal containing a continuous personal identification code and message data multiple times, and the receiving side performs averaging, which takes the average of multiple blocks. Conventionally, methods have been proposed to increase the reception sensitivity and expand the service area by improving the S/N ratio without increasing the transmission level.

[Problem to be solved by the invention]

However, when a signal program consisting of a continuous personal identification code and message data is retransmitted multiple times by averaging, the number of data contained in one block is several hundred bits, so if the number of retransmissions is, for example, 100, then The total number of bits is zero, and the time required to call a destination and send a message is extremely long, which consumes a lot of battery power in the receiver, and the waiting time in other receivers increases by that time. There is a problem with becoming.

In order to reduce this transmission time, it is desirable to increase the data transmission rate. However, as the data transmission rate increases, the occupied frequency bandwidth of the signal increases, so it is necessary to widen the bandwidth of the receiver's bandpass filter, but this also increases the amount of external noise that enters the receiver. /N
The ratio worsens.

Bandwidth is often regulated by legislation.

The present invention has been made to solve these conventional problems, and it is an object of the present invention to provide a wireless paging system that can shorten waiting time due to retransmission and reduce battery consumption.

[Means to solve the problem]

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 the repeated signal transmitted from the transmitter, averages it, and reproduces it. In the wireless paging system, the receiver extracts an error detection code included in the data each time the data is averaged, and when it is determined that there is no error, the receiver is equipped with an error detection means that causes the averaging means to stop the averaging operation. It is characterized by

[For production]

The repeatedly transmitted data includes an error detection code such as a CRC code. This error detection code is detected by the error detection means, but if no error is detected, a signal is issued to the averaging means to stop the averaging operation, so no averaging is performed after that, and the display etc. , the power consumption in the receiver is reduced, and the time occupied by data due to retransmission is also reduced, so the waiting time in other receivers is also reduced.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail 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, a keyboard 1 is connected to a transmitter 10 for inputting an ID code, which is an identification code unique to a pager subjected to paging, and a message, which is the content of the transmission. The data is input to the continuous reproduction data generation circuit 2 inside.

FIG. 2 shows the data output from the continuous playback data generation circuit 2. Following a preamble of, for example, 10 bits, which indicates the start of transmission, an ID code of, for example, 16 bits, for example, of 100 bits is shown. CRC for message and error detection (Cyc Red
A data block with a period T consisting of a undancyCheck) code is retransmitted 100 times.

The data blocks generated in the continuous reproduction data generation circuit 2 in this way are sent to the modulation circuit 3 at a carrier frequency of 400, for example.
The signal is FM modulated at MHz and sent into the air via a transmitting circuit 4 including an antenna.

The transmitted signal is received by a receiving circuit 11 equipped with an antenna in the receiver 20, demodulated by a demodulating circuit 12, and then averaged, which will be described later, by an averaging processing circuit 13. The averaging results are input to the message decoding circuit 14 and the ID code to the discriminating circuit 17, respectively.

! In the D code discrimination circuit 17, the averaging processing circuit 1
The ID code portion is selectively extracted from the signal obtained by the processing in step 3, and compared with the ID code stored in the ROM provided in the ID code discrimination circuit. If the two match as a result of this comparison, the buzzer drive circuit 1
8 causes the buzzer 19 to sound, informing the recipient that the message has been sent. Further, a drive signal is sent from the ID code discrimination circuit to the display drive circuit 15 and the display 16
display. 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, the contents of the ID code part of the received signal and the stored ID
If the codes do not match, the ID code discrimination circuit 17 sends information to the buzzer drive circuit 18 and the display drive circuit 15.
Since a discrepancy signal is generated, the buzzer 19 does not sound and the display 16 does not display anything.

FIG. 3 is a block diagram showing the detailed configuration of the averaging processing circuit 13, in which the signal e1 inputted to the input terminal 31 passes through the adder circuit 32 and is then 1 block delay 33.
It is stored with a block delay, and its output is sent to the switch 35.
and is fed back to the other side input of the adder circuit 32. Note that the output of the 1-block delay 33 was previously set to 0 level due to human input.

The signal el is also input to a level conversion start detection circuit 34, and the output of this circuit is supplied to a switch 35 to operate it. The output side of switch 25 is 1/n
It is applied to the decoder 37 via the multiplier circuit 36 and output to the output terminal 3.
An output signal is taken from 8. Therefore, the received data block is added to the previous data block and this value is divided by the number of additions, resulting in data averaging. For example, the S/N ratio improved by averaging n times is 31og2n (
dB), so if the number of retransmissions is n-100, the S/N is
The ratio will be improved by about 20 dB, and the service area will be expanded about three times.

Furthermore, in this embodiment, the averaging processing circuit 1
An error detection circuit 21 receiving the output of 3 is provided,
Here, the CRC code in the data mentioned above is checked. When no errors occur as a result of this check, the error detection circuit 21 outputs a signal to the averaging processing circuit 13 to stop averaging. This signal activates the level conversion start detection circuit 34 in the averaging processing circuit 13, stops addition for each block, switches the switch 35, and takes out the averaging result.

This means that the averaging has finished, so
The buzzer calling and display operations described above are performed. Therefore, if the reception condition is good and there are no errors, averaging is rarely performed (immediately the buzzer
- There is no needless consumption of power because the operation transitions to call and display operations and then stops. Also, in other receivers, the time occupied for data transmission is reduced and the waiting time is reduced.

In the above embodiment, CRC is used as the error detection code.
Although a code is used, other error detection codes such as parity may be used.

Furthermore, although the embodiment has shown a system that transmits by radio waves, the present invention can be similarly applied to a system that transmits by optical radio.

〔Effect of the invention〕

As described above, according to the present invention, the error detection code included in the data is extracted every time received data is averaged, and the error detection code is caused to stop the averaging operation at the time when it is determined that there is no error. Since a detecting means is provided, when it is determined that there is no error, the process immediately shifts to calling and displaying, so power consumption can be significantly reduced by not performing any extra operations. Furthermore, since the time occupied for data transmission is reduced, waiting time can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a wireless paging system according to the present invention, FIG. 2 is an explanatory diagram showing the configuration of transmitted signals, and FIG. 3 is a block diagram showing the configuration of an averaging processing circuit. DESCRIPTION OF SYMBOLS 1...Keyboard, 2...Continuous retransmission 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 device, 17...! D 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 power, arithmetic circuit, 37...Decoder. Applicant's agent Mr. Sato

Claims (1)

[Claims] 1. A receiver that includes a transmitter that repeatedly transmits data to be transmitted a predetermined number of times, and averaging means, and that receives the repeated signal transmitted from the transmitter, averages it, and reproduces it. In the wireless paging system, the receiver extracts an error detection code included in the data each time the averaging is performed, and when it is determined that there is no error, it causes the averaging means to perform an averaging operation. A wireless paging system characterized by comprising error detection means for stopping the paging system.