JPH01181241A - Radio paging system - Google Patents

Abstract

PURPOSE:To decrease the time occupied by data transmission and to reduce the waiting time by extracting an error detection code included in a data in case of transmission from a master equipment to a slave equipment and transmitting a transmission stop command from the slave equipment to the master equipment at the point of time of deciding that there exists no error. CONSTITUTION:A sent signal is received by an antenna 11 in the slave equipment 20, subjected to various processings such as demodulation by a reception circuit 12 and subjected to averaging being the processing of averaging data by an averaging processing circuit 13. Furthermore, the output of the averaging processing circuit 13 is inputted to an error detection circuit 14, and a transmission circuit 16 receiving a signal representing no error existence transmits a transmission stop command from the antenna 11. Since the transmission stop command is transmitted to the master equipment when the reception state is excellent and data transmission from the master equipment to the slave equipment is implemented without error in this way, no unnecessary transmission/reception is executed, the channel occupying time is reduced and the waiting time is decreased and the power consumption in the entire radio paging system is reduced.

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 block containing 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, all bits are The problem is that the number of bits is lost, and the time required to call a destination and send a message becomes very long, which increases the waiting time in other receivers and increases battery consumption. be.

In order to reduce this waiting 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 deteriorates, leading to a decrease in reception sensitivity.

The present invention has been made to solve these conventional problems, and provides a wireless paging system that can shorten waiting time due to retransmission without reducing reception sensitivity, and can reduce battery consumption. The purpose is to

[Means to solve the problem]

According to the present invention, a master device includes a first transmitting means that repeats data to be transmitted a predetermined number of times and transmits the same at a first frequency;
In a radio paging system comprising a first receiving means for receiving a repeated signal transmitted from a base unit, and a slave unit having an averaging means for averaging and reproducing data received by the receiving unit, the slave unit includes: error detection means for extracting an error detection code included in the data in the averaging poison;
and transmitting means for transmitting a transmission stop command at a second frequency when the error detection means determines that there is no error, and the transmitter receives the transmission stop command and transmits the transmission to the first transmitting means. It is characterized in that it includes a second receiving means for stopping the reception.

[For production]

The data transmitted from the transmission means of the base unit is received by the reception means of the slave unit, and the results are averaged by the averaging means and an error detection code is detected by the error detection means, but it is determined that there is no error. At the point in time, the transmitting means of the slave unit issues a transmission stop command to the base unit. The receiving means of the base unit receives this command and stops data transmission.

Therefore, no transmission is performed thereafter, the channel occupation time is reduced, the waiting time is reduced, and the power consumption in the base unit and the slave unit is 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 the base unit 10 as an input device for inputting an ID code, which is an identification code unique to the pager receiving paging, and a message, which is the content to be sent, and the output of the keyboard 1 is The signal is input to the transmitting circuit 2 in the transmitter 10. This transmitting circuit composes data to be transmitted, FM modulates the data at a carrier frequency of 400 MHz, for example, and transmits the data into the air through the antenna 4.

FIG. 2(a) shows data transmitted from the transmitting circuit 2. Following a preamble of, for example, 10 bits indicating that transmission is to be started, an ID code of, for example, 16 bits, for example, of 100 bits is shown. CRC (Cyclic Redundancy) for message and error detection
A data block of period T consisting of a Check) code is repeatedly retransmitted.

The transmitted signal is received by the antenna 11 in the handset 20, demodulated by the receiving circuit 12, and then averaged by the averaging processing circuit 13. The averaging results are input to a processing circuit 15 including a message decoding circuit and an ID code discriminating circuit (neither shown). In this processing circuit 15, the ID code portion is selectively extracted from the signal obtained by the processing in the averaging processing circuit 13, and this and R
Compare with the ID code stored in OM.

If the two match as a result of this comparison, the buzzer 17 will sound to notify the recipient that the message has been sent. Further, the message data decoded by the message decoding circuit is displayed on the display 18. On the other hand, I of the received signal
If the contents of the D code section and the stored ID code do not match, the ID code discrimination circuit generates a mismatch signal, so the buzzer 17 does not sound and the display 18 does not display the information. do not have.

Further, the output of the averaging processing circuit 13 is input to an error detection circuit 14, which checks the CRC code in the data described above. Figure 2 (b
) shows that an error is detected in this way, and this signal is given to the averaging processing circuit 13 to continue averaging.

No error is detected in the next block in FIG. 2(b). This causes the error detection port 14 to
) A check result signal indicating that there is no error is output. Averaging can also be stopped by inputting this signal to the averaging processing circuit 13.

Furthermore, upon receiving the signal indicating that there is no error, the transmitting circuit 16 transmits a transmission stop command from the antenna 11. In order to prevent interference, the transmission frequency at this time must be different from the transmission frequency from the base unit to the slave unit, for example, 40
It is 1MHz. The output of the error detection circuit 14 is given to a processing circuit 15 for controlling display processing and the like.

The transmission stop command transmitted in this manner is received by the antenna 4 of the base unit 10, demodulated by the reception circuit 3, and then given to the transmission circuit 2. As a result, the operation of the transmitting circuit 2 is stopped, so data transmission is no longer performed.

In this way, if the reception condition is good and data is transmitted from the base unit to the slave unit without errors, a transmission stop command is sent to the base unit, eliminating unnecessary transmission and reception and reducing channel occupation time. This reduces latency and reduces power consumption in the overall wireless paging system.

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 O level due to manual input.

The signal e1 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
The signal is applied to a decoder 371 via a multiplication circuit 36, and an output signal is taken out from an 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, resulting in data averaging. For example, based on information theory, the S/N ratio improved by averaging n times is 31og2n(d
B), so if the number of retransmission ports is n-”100, then SN
The ratio will be improved by about 20 dB, and the service area will be expanded about three times.

Note that, as described above, the output of the error detection circuit may be supplied to the level conversion detection circuit 34 to terminate the averaging at the time when no error is detected.

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 when the data is transmitted from the base unit to the slave unit, and when it is determined that there is no error, the slave unit issues a transmission stop command to the base unit. Since the time occupied by data transmission is reduced, the waiting time can be reduced. Furthermore, since unnecessary operations are not performed, power consumption can be significantly 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. 1... ID code/message input device, 2... Transmitting circuit, 3... Receiving circuit, 4.11... Antenna,
DESCRIPTION OF SYMBOLS 10... Base unit, 12... Receiving circuit, 13... Averaging processing circuit, 14... Error detection circuit, 15...
... Processing concave path, 16... Transmission circuit, 17... Buzzer drive circuit, 18... Buzzer, 20... Slave unit, 32...
...Adder, 33...1 block delay circuit, 34
...Level conversion start detection circuit, 35...Switch,
36...1/n multiplication circuit, 37... decoder. Applicant's agent Mr. Sato

Claims (1)

[Scope of Claims] 1. A base unit including a first transmitting means for repeating data to be transmitted a predetermined number of times and transmitting it at a first frequency; and a first unit for receiving the repeated signal transmitted from the base unit. In a wireless paging system, the handset includes a receiving means and an averaging means for averaging and reproducing data received by the receiving means, wherein the handset detects errors included in the data each time the averaging is performed. The transmitter includes an error detection means for extracting a detection code, and a transmission means for transmitting a transmission stop command at a second frequency when the error detection means determines that there is no error, and the transmitter receives the transmission stop command. A wireless paging system comprising: second receiving means for causing the first transmitting means to stop transmitting.