JPH06120869A - Radio selective call receiver - Google Patents

Abstract

PURPOSE:To provide a radio selective call receiver which enables an owner of a receiver to easily recognize the omission of the received message signals and can improve the omission detecting reliability in a radio paging system which adds a series of numbers to each message signal for each address receiver in order to detect the omission of a series of messages sent from a base station at an optional time interval. CONSTITUTION:A decoder 14 decodes a call signal and a message signal from a selective call signal Sa which is received and demodulated by a receiver/ demodulator 12. Then the decoder 14 decides whether these decoded signals are addressed to its own or not. A CPU 20 stores the message addressed to its own in a message memory 21 and also stores temporarily a series of numbers of message signals in a buffer 23 to calculate the difference from a series of numbers stored in a register 22 immediately before reception. When the calculated difference is equal to 2 or more, a reception omission alart signal generator 17 outputs a reception omission alart signal FA. Then a tone is produced through an amplifier 18 and a speaker 19 to show the reception omission of a message.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio selective call receiver for receiving a message included in a call signal transmitted from a base station by a radio frequency carrier, and more particularly to a radio selective call receiver suitable for receiving a message signal having a serial number. Regarding call receiver.

[0002]

2. Description of the Related Art A radio selective calling receiver (hereinafter referred to as a receiver) in a paging system using radio frequency signals is modulated by a digital selective calling signal including a calling number (address) signal and a message signal and transmitted from a base station. It receives the radio frequency signal, demodulates it into the digital selective call signal, and decodes the signal into the call number signal and the message signal. When this calling number signal matches with the own calling number stored in the memory built into the receiver, a notification operation such as sounding and vibration by the notification means such as a speaker and a message display by the message display means are performed to call the receiver carrier. Let us know that there is.
In recent receivers of this type, a message can be received without ringing sound by the switch operation of the receiver carrier. That is, in the reception mode without ringing sound, every time a call signal addressed to itself from the base station is received, the message signal included in the call signal is accumulated in the memory built in the receiver and received by the display means. Normally, only the number of message signals stored in the memory is displayed. The receiver carrier recognizes the presence or absence of the stored message signals from the display, and displays the message signals on the display means by operating the switch.

This type of receiver having such a ringing-free reception mode is described in U.S. Pat. S. Patent No. 4,412,217 (1
October 25, 983) “PAGE WITH VI
SILE DISPLAY INDICATING
STATUS OF MEMORY (Pager with visible display Indicating status of memory) ”. That is, this U.S. S. The receiver of Japanese Patent No. 4,412,217 receives a ringing signal, stores the message signals contained therein, displays the number of received and stored message signals, and according to the receiving order in those messages. It has functions such as assigning numbers and facilitating selective display of messages.

The message reception without ringing sound according to the prior art as described above enhances the confidentiality of the call or message addressed to the receiver carrier and contributes to the expansion of the use of the receiver.

On the other hand, when the call signal addressed to itself is transmitted from the base station as a radio frequency signal,
If the receiver carrier is outside the service area or inside the tunnel, the ringing signal will not be received by the receiver. In the case of a receiver that is always accompanied by a ringing sound, the above-mentioned lack of reception easily leads to another call from the caller, so the problem is small, but there is no ringing reception mode (with message storage memory). Since the receiver cannot recognize the lack of reception at the receiver, this may cause serious problems depending on the content of the transmitted message.

In order to enable the receiver carrier to confirm the presence or absence of the above-mentioned lack of reception, at the base station, each subscriber (radio selective call receiver) is added to the beginning of each message signal in the selective call signal. The method of inserting a serial number has recently begun to be adopted. According to this method, since this serial number is displayed on the display means of the receiver together with the message, the lack of reception is recognized by the receiver carrier and can be easily relieved by contacting the paging service company or the like.

[0007]

However, the above-mentioned U.S.P. S. Prior art receivers, including U.S. Pat. No. 4,412,217, have not been fully capable of receiving such serially numbered message signals. That is, in the receivers according to those prior arts, the above-mentioned serial number is only displayed on the display means as a part of the received message signal. You must remember the number at all times. Not only is it a burden on the receiver carrier,
The reliability of recognition of reception loss cannot be ensured.

Therefore, it is an object of the present invention to provide a radio selective calling receiver which facilitates recognition by the receiver carrier of the above-mentioned missing reception.

[0009]

SUMMARY OF THE INVENTION A radio selective call receiver according to the present invention comprises means for receiving from a base station a radio frequency signal modulated by a digital selective call signal including a call number signal and a message signal, and the radio selective call receiver. Means for demodulating a frequency signal into the digital selective calling signal, means for decoding the selective calling signal into the calling number signal and the message signal, and selectively generating a calling alert in response to the output of the decoding means. Means and a display means for selectively visually displaying the output of the decoding means, and a radio selective call receiver capable of receiving a series of the message signals transmitted from the base station at an arbitrary time interval, A means for detecting a serial number included in the message signal and indicating a transmission order from the base station, and a latest serial number output from the detecting means are displayed. A first storage means for temporarily storing, and at least the latest received sequence number corresponding to the message signal received immediately before the message signal to which the latest sequence number belongs among the series of message signals belongs to at least the latest sequence number. Second storage means for storing until the time of receiving the message signal, means for subtracting the output of the second storage means from the output of the first storage means, and output of the subtracting means being 2 or more Includes means for issuing an alarm.

In the above structure, the latest serial number and the immediately preceding received serial number are also displayed on the display means, and the output of the call alert generating means and the output of the alarm generating means are distinguished from each other. It may be configured to have a signal format that can be used.

[0011]

The present invention will be described below with reference to the drawings.

The radio selective calling receiver of one embodiment of the present invention shown in FIG. 1 demodulates a radio frequency signal transmitted from a base station (not shown) and received by an antenna 11 into the digital selective calling signal. The receiver / demodulator 12 for generating the digital selective calling signal Sa, and whether or not the calling number signal included in the digital selective calling signal Sa and its own address stored in the address memory 13 built in the receiver match. A decoder 14 for detecting and recognizing a call addressed to itself. A microprocessor (hereinafter abbreviated as CPU) 20 receiving the output of the decoder 14 is a program memory (not shown, the same hereinafter) storing a sequence of instructions to be executed, that is, a program, and a program for designating a read address of this memory. A counter, an instruction decoder that decodes an instruction read from this memory and supplies a control signal corresponding to the instruction to the inside and outside of the CPU, and an operation unit that performs various operations such as arithmetic operation and logical operation via an accumulator,
It incorporates a system clock generator for generating a system clock and a data bus, and operates according to the program read from the program memory. Decoder 1
When the output of 4 indicates that the received calling number signal and the address of itself from the memory 13 match, the CPU 20 instructs the calling alert signal generator 16 to generate a calling alert signal, and generates a signal in response to this instruction. The device 16 generates a ring alert signal PA. When the CPU 20 detects the above-mentioned reception loss by means and procedures described later, the CPU 20
Instructs the reception missing alert signal generator 17 to generate a reception missing alert signal, and in response to this instruction, the signal generator 1
7 generates a reception missing alert signal FA. These signals PA and FA are amplified by the amplifier 18 and applied to the speaker 19, and generate a sound of an audible frequency.

On the other hand, when the decoder 14 detects that the received calling number signal matches the memory 13, the decoder 1
The message signal destined for this receiver supplied to the CPU 20 from 4 is stored in the message memory 21. The memory 21 is composed of a random access memory (RAM), and receives a message from the digital selective call signal Sa.
It is stored together with the above-mentioned serial number included in. Register 2
2 stores the serial number of the message signal received immediately before the reception of the received message, and the buffer 23
Temporarily stores the serial number of the message signal just received. These received messages and related serial numbers are displayed on the message display unit 31 formed of a liquid crystal display panel via the display control unit 30. It should be noted that the receiver itself with a data display that employs a microprocessor belongs to the publicly known art, and its configuration is described in U.S. Pat. S. Patent No. 4,41
No. 2,217, etc., the description will be limited to the parts related to the gist of the present invention.

Referring to FIG. 2A showing an example of the signal format of the digital selective call signal Sa, this signal Sa is a so-called POCSAG (Post Office).
Code Standardization Advi
This is a standard format of the sory group (see CCIR Recommendation 584). That is, the signal Sa includes a preamble signal P having a length of 576 bits, which is formed by repeating "1" and "0", and a plurality of batches each including 17 codewords (32 bits in length of each codeword). Composed of. These codewords forming each batch form two frames, each of which is adjacent to each other except for the first one (SC) for synchronization, and thus forms a total of eight frames. The calling number signal A consists of one codeword and is inserted at a predetermined frame position of the above eight frames. Following the call number signal A, a message signal M consisting of a number of message codewords M0-Mn according to the size of the message to be transmitted is inserted. A predetermined idle code I is inserted in the remaining time slots assigned to these signals A and M.

A plurality of combinations of the calling number signal A and the message signal M can be included in one calling signal Sa. Each of these signals is configured 32 to allow distinction between the calling number signal A and the message signal M.
MSB (Most Signi) of bit codeword
ficant Bit) as a flag bit. That is, the flag bit "0" indicates that the code word is the calling number signal A, and the flag bit "1" indicates any of the message code words M0-Mn (FIG. 2 (b), 2 (c) and 2 (d)).
A check bit of 11 bits in length for error correction is added to each of the code words of these signals A and M (FIG. 2 (b), FIG. 2 (c) and FIG. 2 (d)).

In the digital selective call signal Sa to which the receiver of the present invention is compatible, the POCSAG mentioned above is used.
Of the 20 message bits of the first message codeword M0 of the system compatible format message signal M, 4 bits from the 2nd bit to the 5th bit are assigned to the data bit 201 corresponding to the serial number inserted by the base station, and 16 bits from 6th bit to 21st bit are allocated to the data bits 202 for the message addressed to the receiver (FIG. 2 (c)). For the subsequent message codewords M1 to Mn, this sequence number is not necessary, so the entire data bit 201 is also assigned to the data bit 202 for the message (FIG. 2 (d)).

Referring also to FIG. 3, which is a flow chart showing a procedure of signal processing leading to detection of reception loss, a digital selective call signal Sa obtained by demodulating a radio frequency signal from the antenna 11 by the reception / demodulator 12 is obtained. Is supplied to the decoder 14 (step 501), and the decoder 14 determines whether the address determined by the address code included in the calling number signal A in the signal Sa and the position of the inserted frame and the own address stored in the address memory 13 match. Is detected (step 502), the decoder 14 puts the CPU 20 into the operating state and calls the call number signal A.
Then, the message signal M following is sent to the CPU 20 (step 503).

The CPU 20 is activated by the decoder 14 and sends a command to the call alert signal generator 16 to generate the alert signal PA. The signal PA is composed of pulses having a period of 1 second and a duty factor of 75% as shown in FIG. The call alert signal PA is amplified by the amplifier 18 and drives the speaker 19 to notify the receiver carrier of the call.

On the other hand, the CPU 20 stores the second to fifth bits of the message code word M0 representing the serial number of the above-mentioned message signal M in the buffer 23 (step 504) and also flags of the code words M0-Mn. Message part except bits and check bits, that is, 2nd to 21st bits (data bit 20
1 and 202) in the message memory 21.
Since the register 22 stores the serial number of the message signal received immediately before the message signal, the storage content of the register 22 is subtracted from the storage content of the buffer 23 (step 505). When the difference between the two is 2 or more (YES in step 506), the CPU 20 sends an activation command to the reception missing alert signal generator 17 (step 507). In response to this command, the signal generator 17 generates the alert signal FA, and the signal FA
Is amplified by the amplifier 18 and drives the speaker 19. As shown in FIG. 5, this signal FA is composed of pulses having a cycle of 200 ms and a duty factor of 50% so that it can be distinguished from the call alert signal PA. On the other hand, the difference detected in step 506 is 1 (N in step 506
In the case of O), the activation command is not supplied from the CPU 20 to the signal generator 17. In any case, step 50
When the signal processing up to 7 is completed, the CPU 20 causes the buffer 23
The stored contents of (1) are transferred to the register 22 to prepare for a check for reception failure of the subsequent message signal (step 508).

When the receiver is used for the first time in a paging service network with message signal sequence number assignment, the sequence number stored in the register 22 is set to an initial value 0. Further, the content stored in the register 22 is increased by 1 each time a message signal addressed to itself is increased to reach 15 and when the next message signal is received, the content stored in the register 22 is returned to 0. So CPU2
0 is programmed.

The message code words M0-Mn stored in the message memory 21 are displayed on the display section 31 under the control of the CPU 20. That is, the codeword M0
The four data bits 201 corresponding to the above-mentioned sequence number and the other data bits 202 which form part of the above, and the data bits 20 of the other message codewords M1 to Mn.
2 is also displayed on the display unit 31. Further, the contents stored in the register 22, that is, the serial number of the message received immediately before is also displayed on the display unit 31. The latter side-by-side display facilitates the receiver carrier's recognition of the occurrence of missed reception and identification of missed messages.

Referring to FIG. 6 showing an example of the display appearing on the display unit 31, the display immediately after the message signal of the serial number "6" is received is shown in the same figure. Since the serial number "1" of the message signal received immediately before is also displayed, it can be seen that the reception of the four message signals of serial numbers "2" to "5" is missing.

Referring to FIG. 7, which shows a display similar to that of FIG. 6, it is indicated that the message signal received immediately before the message signal having the serial number "8" has the serial number "7". It can be seen that there was no omission.

In the embodiment shown in FIG. 1, the register 2
Reference numeral 2 is a non-volatile memory, such as an EEPROM.
Alternatively, if a non-volatile memory is not used, a memory with a backup battery is adopted to hold the stored data.

In the above embodiment, the digital selective call signal conforms to the POCSAG standard system. However, the idea of the present invention is not limited to the standard system, but paging by the digital selective call signal of other formats is also possible. It will be obvious that the method can be applied.

[0026]

As described above, since the receiver according to the present invention automatically detects the lack of reception of the message signal and issues an alarm, the receiver wearer can surely recognize the lack of reception. Further, since the serial number of the last received message signal can be displayed together with the serial number of the newly received message signal on the display unit, it becomes easy to recognize the above-mentioned reception loss and identify the missing message signal.

[Brief description of drawings]

FIG. 1 is a block diagram of a radio selective call receiver according to an embodiment of the present invention.

2A to 2D are diagrams showing a signal format of a digital selective call signal.

3 is a flowchart showing a procedure of signal processing leading to detection of reception loss and alarm generation in the embodiment of FIG.

4 is a waveform diagram of a ring alert signal in the embodiment of FIG.

5 is a reception missing alert signal in the embodiment of FIG. 1 >>
It is a waveform diagram of.

FIG. 6 is a diagram showing an example of a display that appears in the message display means of the embodiment shown in FIG. 1 when reception omission occurs.

7 is a diagram showing an example of a display appearing on the same message display means as in FIG. 6 when there is no reception omission.

[Explanation of symbols]

 11 antenna 12 reception / demodulator 13 address memory 14 decoder 16 ring alert signal generator 17 reception missing alert signal generator 18 amplifier 19 speaker 20 microprocessor (CPU) 21 message memory 22 register 23 buffer 30 display control unit 31 message display unit

Claims (3)

[Claims] 1. A means for receiving from a base station a radio frequency signal modulated by a digital selective call signal including a call number signal and a message signal, and means for demodulating this radio frequency signal into the digital selective call signal. Means for decoding the selective calling signal into the calling number signal and the message signal, means for selectively generating a calling alert in response to the output of the decoding means, and the output of the decoding means selectively visible In the radio selective call receiver capable of receiving a series of the message signals transmitted from the base station at an arbitrary time interval, including the display means for displaying, a transmission order from the base station included in the message signal is displayed. Means for detecting a serial number to be displayed, first storage means for temporarily storing the latest serial number output from the detecting means, and the series of messages. A second memory for storing the last-received sequence number corresponding to the message signal received immediately before the message signal to which the latest sequence number belongs among the digital signals at least until the time of receiving the message signal to which the latest sequence number belongs. Means for subtracting the output of the second storage means from the output of the first storage means, and means for issuing an alarm when the output of the subtraction means is 2 or more. Radio selective call receiver. 2. The radio selective calling receiver according to claim 1, wherein the latest serial number and the immediately preceding received serial number are also displayed on the display means. 3. The radio selective call receiver according to claim 1, wherein the output of the call alert generating means and the output of the alarm generating means are in a signal format that can be distinguished from each other.