JPS61269494A - Multiple access radio telephone system - Google Patents

Abstract

PURPOSE:To allow all radio circuits to be used for normal calling and to utilize radio waves effectively by providing a means which makes an interrupt connection for an emergency call if the emergency call is requested when all radio circuits are used for other calls as well. CONSTITUTION:An interruption radio terminal equipment 4 when receiving an emergency signal selects on radio circuit Fh at random, and locks the frequency of a receiver 43 and a transmitter 45 to the radio circuit Fh and also lowers the electric power of a transmit signal below that during calling. A receiver 32 corresponding to the radio circuit Fn of a radio base station device 3 has beats and a concentrator equipment 2 detects the beats and holds the connection of an interrupted subscriber line Ll. An interrupted radio terminal equipment 4 holds the connection of a chargeable circuit 401 and further stop the output of the transmit signal from the transmitter 45. The interrupted radio terminal equipment 4 varies the electric power of the transmitter 45 to the value during calling. The concentrator equipment 2 connects a subscriber line Lk to integrated circuits M1-h and M1-h. Then, the interrupted radio terminal equipment 4 connects the chargeable circuit 401 to the receiver 43 and transmitter 45.

Description

DETAILED DESCRIPTION OF THE INVENTION [Area of Application] The present invention relates to a multiple access radio telephone system, and more particularly to a multiple access radio telephone system used as an emergency interrupt connection in a subscriber radio telephone system.

[Conventional technology]

In remote areas and tourist areas, subscriber wireless telephone systems are used because subscribers are scattered over a wide area and it is not economical to install wired subscriber lines to connect exchanges and telephones. It will be done.

In a subscriber wireless telephone system, m subscriber lines connected to an exchange are converted into wireless lines at a wireless base station, while m telephones corresponding to each subscriber are converted into m subscriber lines connected to the wireless line. Connect to a wireless terminal device by wire. The time probability that each subscriber line is in use is small, and therefore it is not economical to provide the same number of wireless lines as the number of subscriber lines, m. It is common to use a multiple access wireless telephone system in which multiple subscriber lines share a wireless line in response to call requests.

A conventional multiple access wireless telephone system used as a subscriber wireless telephone system will be explained with reference to the drawings.

FIG. 2 is a block diagram showing an example thereof.

In this example, [n pairs of subscriber lines Li
(i is a natural number from 1 to m) to n pairs of concentrator lines M1-j;
2-j (J is a natural number from 1 to n), a concentrator device 2a, and a radio base station device that converts the concentrator line Ml-j; m11I, which is connected one-to-one to subscriber line L1 by sharing 1M2 and wireless line Fj with concentrator line M1-, and 3a with subscriber line L1! It consists of a wireless terminal device 4a of iI, and m telephones TI connected to each of the wireless terminal devices 4a through a wired line 401. The wireless line Fj is composed of a radio wave fj which is a reception wave and a radio wave f''/ which is a transmission wave when viewed from the side of the wireless terminal device 4a.

When the concentrator device 2a detects a call request from a subscriber line sick or a call request from the telephone T1, the concentrator device 2a connects the concentrator line M1, which is not used for calls, between the subscriber line Li and the corresponding telephone Ti. -j; M2-j and wireless line Fj are allocated to establish a call connection.

If all of the concentrator lines Mlj; M2j and the wireless line Fj are allowed to be assigned to normal calls, all of these lines may be used for normal calls and cannot respond to a request for an emergency call. In order to avoid such a situation, the concentration lines M1-j; M23 and the wireless line F
Some of the lines are reserved for emergency calls, and these lines are allocated only when an emergency call is requested.

As explained above, in the conventional multiple access radio telephone system used as a subscriber radio telephone system, some of the radio lines are used exclusively for emergency calls, and the remaining radio lines are used for normal calls. The disadvantage is that the efficiency of using wireless lines as a network is low, and radio waves, which are a limited resource, cannot be used effectively.

[Problem that the invention seeks to solve]

The problem to be solved by the present invention, or in other words, the purpose of the present invention is to eliminate the above-mentioned drawbacks and provide a multiple access wireless telephone system that can respond to emergency call requests and utilizes radio waves effectively. It's about doing.

[Failure to solve the problem]

The multiple access wireless telephone system of the present invention includes a concentrator device that concentrates a plurality of subscriber lines connected to an exchange into a plurality of concentration lines that are less than the number of subscriber lines, and a wireless base station that converts the concentration lines into the same number of wireless lines. In a multiple access wireless telephone system comprising a device, a plurality of wireless terminal devices wirelessly connected via the wireless line, and the telephone connected by wire to each of the wireless terminal devices, the concentrator device includes: a first hold means for holding connection of the subscriber line during a call under the control of a first control means; and a switch means for connecting or disconnecting the subscriber line under the control of the first control means. ,
a line concentration means for concentrating the subscriber lines and converting them from 2 lines to 4 lines;
a plurality of interference wave detection means that output an interference detection signal to the first control means when detecting that there is an interference wave on a corresponding wireless line; and the first holding means when the interference detection signal is input. and the first control means which controls the switch means and performs an interrupt connection for an emergency call together with the wireless terminal device via the concentrator line and the wireless line, and the wireless terminal device includes a second control means. a receiving means that is controlled by a receiver and outputs an electric field signal that is tuned to one receiving frequency of the wireless line and has a value corresponding to the received electric field strength; transmitting means that is tuned to one transmission frequency of a wireless line and outputs a transmission signal having controlled power corresponding to the electrical signal and normal connection and emergency connection; and upon detecting an emergency signal input from the telephone. a signal detection means for outputting an emergency detection signal to the second control means; a second holding means for holding connection of the wired line during a call under the control of the second control means; and the emergency detection signal. is input and there is no vacant line in the wireless line, the transmitter is controlled to output the transmission signal, which is the interference wave, to one of the wireless lines, and the concentrator device is transmitted through the wireless line and the concentrator line. and when it is detected through the concentrator device, the concentrator line, and the wireless line that there is an interference wave on the wireless line used for the call, the second hold means is activated. and the second control means for controlling and suspending connection of the wired line together with the concentrator device via the wireless line and the concentrator line.

[Implementation date]

The present invention will be described in detail below with reference to drawings showing embodiments.

FIG. 1 is a block diagram showing an embodiment of the multiple access wireless telephone system of the present invention.

This embodiment is configured as follows. That is, m pairs of subscriber lines L ii connected to the exchange 1, a concentrator device 2 that concentrates the lines to m pairs of concentrator lines M1j;
The wireless base station device 3 converts the signal into n wireless lines Fj in one-to-one correspondence and outputs the pre-demodulation signal 291, and the subscriber shares the concentrator lines M1-j; M2-j and the wireless line Fj. It is configured to include m wireless terminal devices 4 connected one-to-one to a line Li and connected to a telephone Ti via a wired line 401, and m telephones Ti. The radio line Fj is composed of a radio wave fj which is a received wave and a radio wave fJ/ which is a transmission wave when viewed from the wireless terminal device 4 side.

The concentrator device 2 includes a hold circuit 21 that is controlled by the control circuit 24 via a control line 294 and holds the connection of the subscriber line Li in use to the switch circuit 22;
94 to connect or disconnect subscriber line L1 and concentrator line M1-j; M2-j, and connect subscriber line Li and concentrator line Ml-j; M2-j to signal line. 293, and n interference wave detection circuits that output an interference detection signal 292 to the control circuit 24 when it detects that there is an interference liquid on the corresponding wireless line F by manually inputting the pre-demodulation signal 291. device 23 and signal line 29
3 to subscriber line Li or concentrator line M13; M2
transmits and receives signals with j, inputs the interference detection signal 292,
The control circuit 24 controls the hold circuit 21 or the switch circuit 22 via a control line 294 and performs a connection for a normal call or an interrupt connection for an emergency call. The interference wave detector 23 includes an AM detector that performs AM detection on the pre-demodulation signal 291, and a discriminator that outputs an interference detection signal 292 when the amplitude of the low frequency component of its output is equal to or higher than a certain value.

The radio base station device 3 receives a signal from one of the concentrator lines M1-3 and angle-modulates the radio wave f using the signal.

n transmitters 31 that output angle-modulated radio waves f
When jl is input, it is frequency-changed into an intermediate frequency signal, then angularly demodulated, the demodulated signal is outputted to the other side of the concentrating port -1〇- line Mi-j; M2-j, and the intermediate frequency signal is branched. It is linearly amplified and output as a pre-demodulation signal 291,
n receivers 32 which output squelch signals to the other concentrator line 21j when the radio wave fJ' is not input, and a transmitter 3.
1 and a receiver 32 to an antenna 34, and an antenna 34 for transmitting and receiving radio waves f''/f''/.

The wireless terminal device 4 includes an antenna 41 that transmits and receives radio waves fJ/.fJ, and a receiver 43 and a transmitter 45 that connect the antenna 41 to
is controlled by the control circuit 49 via the control line 498 and the transmitting/receiving duplexer 42 connected to it to tune to one frequency of the radio wave fj, input the radio wave fj as a received signal 491, angle demodulate it, and generate a demodulated signal 492. is output to the holding circuit 48 and the control circuit 49, and the receiver 43 outputs the electric field signal 493 having a value corresponding to the received electric field strength of the radio wave fj. A modulation signal 496 that is controlled by the control circuit 49 and tuned to one frequency of the radio wave f, / and input from the holding circuit 48 or the control circuit 49.
The radio wave fJL is angularly modulated and a transmission signal 495 is generated with controlled output corresponding to the electric field signal 493 and normal connection and emergency connection.
a transmitter 45 that outputs as
1 to a 4-wire system, and detects off-hook/on-knock or transmission of an emergency signal from the telephone Ti via the wired line 401 and the 2-wire/4-wire conversion circuit 46, and detects off-knock signal/on-hook. An emergency signal detector 47 outputs a signal or an emergency detection signal to the control circuit 49 via a signal line 497, and is controlled by the control circuit 49 via a control line 498 and connected via a wired line via a 2-wire/4-wire conversion circuit 46. The line 401 is connected or disconnected from the receiver 43 and the transmitter 45, and the connection of the wired line 401 to the receiver 43 and the transmitter 45 during a call is put on hold via the 2-wire conversion circuit 46. The circuit 48 inputs the signal via the signal line 497 and the demodulated signal 492, outputs the modulated signal 496, and outputs the modulated signal 496 via the control line 498 to the receiver 43/level signal generator 4.
4. A control circuit 49 that controls the transmitter 45 or the hold circuit 48 and holds the connection of a normal call, an interrupt connection of an emergency call, or a connection of the wired line 401 during a call. The receiver 43 includes a frequency converter that inputs a received signal 491, converts the frequency into an intermediate frequency signal, and outputs it, an intermediate frequency amplifier that amplifies and outputs the output, and angle demodulates the output and outputs a demodulated signal 492. It is equipped with a demodulator. The intermediate frequency amplifier includes a variable gain amplifier whose gain is controlled by a voltage signal, a detector that branches and detects the output thereof, and a DC amplifier that amplifies the output and outputs a voltage signal. The voltage signal is negatively fed back to the variable gain amplifier to create an automatic gain control loop, so the output level of the intermediate frequency amplifier remains constant regardless of changes in the input level. The voltage signal is branched and output as an electric field signal 493.

Next, the operation of the embodiment shown in FIG. 1 will be explained.

All of the transmitters 31 of the radio base station device 3 have the same power Pi.
It constantly outputs 5dBW radio waves fj. The radio wave fj of the radio line Fj used for the telephone call is modulated by a telephone call signal input to the transmitter 31 from one side 20j of the corresponding concentrator line. When there is a wireless line Fj that is not used for a call, an idle line signal tone is input from the control circuit 24 of the concentrator device 2 to the transmitter 31 corresponding to one of them via the signal line 293 and one side 20j of the concentrator line. and the corresponding radio wave fj is modulated with this signal tone. Radio waves fj of other wireless lines Fj other than this wireless line Fj and the wireless line FJ which is completely used for telephone calls are not transmitted.

The receiver 43 of the wireless terminal or terminal device 4 during a call receives a value corresponding to the received field strength of the radio wave fj of the wireless line Fj used for the call, that is, the input power (PrdBW) of the received signal 491.
An electric field signal 493 having a value corresponding to The correspondence relationship between the value of the electric field signal 493 and the value of the transmission level signal 494 in the level signal generator 44 is controlled by the control circuit 49 during a call, as will be explained below.

That is, the input power of the radio wave fJ/ input to the receiver 32 of the wireless base station device 3 is set to a constant value "rs dBW, and the power of the transmission signal 495 outputted from the transmitter 45 (PtdBw
) is determined by the relational expression Pt=Pts+PrsPr. Since the loss of the radio wave f on the path from the output end of the transmitter 31 to the input end of the receiver 43 is almost equal to the loss of the radio wave fj on the path from the output end of the transmitter 45 to the input end of the receiver 32, the reception The receiver 32 of the radio base station 3 maintains the same power (Prs dB W
) input the radio wave fjI.

The receiver 43 of the wireless terminal device 4 that is not on a call synchronously scans each wireless line F1 under the control of the control circuit 49, and when the control circuit 49 detects that there is an idle line signal tone in the demodulated signal 492, the receiver 43 scans each wireless line F1 synchronously under the control of the control circuit 49. The transmitter 45, which is frequency-locked to the wireless line Fj and is not in use, stops outputting the transmission signal 495.

Wireless line F, dust, subscriber line L not used for calls
The call request from 1 is sent to control circuit 2 via line 16 293.
4, or when the control circuit 49 detects a call request from the telephone FAT via the signal line 497, the control circuit 24 and the control circuit 49 connect the concentrator line Mlj; The selective calling signal tone output from the control circuit 24 and the number registration signal tone output from the control circuit 49 are transmitted and received through the concentrator lines M 1-''; M 2-J and Subscriber line Li and telephone T using wireless line F.
Establish a call connection with I.

When the telephone Ti requests an emergency call and sends out an emergency signal, the emergency signal detector 47 outputs an emergency detection signal to the control circuit 49 via the signal line 497. In this case, if there is a wireless line FJ that is not used for a call, a connection similar to a normal call is made. When all of the wireless lines Fj are used for other calls, an interrupt connection for an emergency call is made.

FIG. 3 is a flowchart showing the interrupt connection operation at the start of an emergency call.

The operation of interrupt connection for emergency calls will be explained with reference to FIG.

All of the wireless lines Fj are used for other calls, and the emergency signal detector 47 detects the telephone Tk (k is a natural number from 1 to m).
When detecting an emergency signal from (step 901), the control circuit 49 receives the emergency detection signal via the signal line 497, detects this, and connects one wireless line Fh (h is 1 to
n (natural number) is selected at random, and the receiver 43 and transmitter 45 are frequency-locked to the wireless line Fh. The level signal generator 44 is also controlled to set the power of the transmission signal 495 to a value lower (for example, about 20 dB) than the power during a call (step 3). That is, the transmission signal 495 at this time
The power (PtdBW) is expressed by the relational expression Pi:Pj, +P, , -
Made of Pr-20. Note that the transmission signal 495 is unmodulated.

Receiver 32 corresponding to the wireless line Fh of the wireless base station device 3
, the telephone Tl that is making a call using the wireless line Fh
(l is a natural number from 1 to m) The desired wave from the wireless terminal device 4 corresponding to the telephone Tk and the interference wave from the wireless terminal device 4 corresponding to the telephone Tk are input, and a beat occurs in the pre-demodulation signal 291, causing interference. The wave detector 23 detects this beat and outputs an interference detection signal 292 to the controller 24 (step 904).
).

The interference wave ratio D/U to the interference wave is 20dB, and the interference wave detector 23 having the configuration described above reliably detects the interference wave with a D/U of 20dB (for example, in Japanese Patent Laid-Open No. 58-151736).
Publication No.).

The speech signal to interference output ratio S/I of the demodulated signal outputted by the receiver 32 is S/I== assuming that the standard modulation degree is m radians.
It is expressed as D/U+2010gm. The standard modulation depth of transmitter 45 is chosen to be 3.0 radians. D/U is 20d
B, the S/I is 29.5 dB, and even if there is an interference wave, it is possible to continue the conversation between the telephone Tl and the subscriber line LO.

When the interference detection signal 292 is input to the control circuit 24,
The subscriber line Ll and one of the concentration lines M are connected via the signal line 293.
1- A hold signal is immediately output to give a notice of hold to the caller using the wireless line Fh. When the predetermined advance notice period has elapsed, the hold circuit 21 is controlled by the control circuit 24 to hold the connection of the subscriber line Ll (step 906). That is, the loop on the exchange 1 side of subscriber #Ll is closed, and the switch circuit 22 side is disconnected.

The control circuit 49 of the wireless terminal device (hereinafter referred to as the interrupted wireless terminal device) 4 corresponding to the telephone T, 5 receives the demodulated signal 492.
When a hold signal is detected and a certain notice period has passed,
The hold circuit 48 is controlled by a control circuit 49 and connected to the wired line 40.
1 connection is put on hold. The control circuit 49 outputs the suspension completion signal as the modulation signal 496 (step 908).

When the control circuit 24 of the concentrator device 2 receives the hold completion signal, it stops outputting the hold signal, and transmits the interrupt recognition signal to one side M, , -k of the concentrator line via the signal line 293.
(steps 909 and 910).

When the control circuit 49 of the interrupted wireless terminal device 4 detects that the reception of the hold signal has stopped, it stops sending out the hold completion signal, and controls the transmitter 45 to stop outputting the transmission signal 495 from the transmitter 45. Stop (steps 911 and 912)
).

When the control circuit 49 of the wireless terminal device (hereinafter referred to as the interrupt wireless terminal device) 4 corresponding to the telephone Tk receives the interrupt recognition signal, it controls the transmitter 45 to set the power of the transmitted signal 495 to the already-described value during the call. The modulated signal 496
A number registration signal is sent as (step 913).

When the control circuit 24 of the concentrator device 2 starts receiving the number registration signal, it stops the output of the interrupt recognition signal and outputs the selective call signal, and when the output is completed, it controls the switch circuit 22 to call the subscriber. Line Lk and concentration line M
1-11; Connect with M2-11 (step 91
4-916).

When the interrupt wireless terminal device 40 control circuit 49 receives the selective call signal, it controls the hold circuit 48 to connect the wired line 401 to the receiver 43 and transmitter 45.

This completes the interrupt connection operation at the start of an emergency call.

FIG. 4 is a flowchart showing the interrupt connection release operation at the end of an emergency call.

Referring to FIG. 4, the operation of canceling the interrupt connection of 7 ++@ at the end of an emergency call will be explained.

The control circuit 24 of the concentrator device 2 switches the subscriber line Lk/signal line 29 on-hook of the telephone on the receiving side of the interrupt call.
3 (step 918), the interrupt connection release operation starts.

The control circuit 24 controls the switch circuit 22 to connect the subscriber line L.
K and the concentrator line Ml-h: M2h are disconnected, and a disconnection signal is sent to one side of the concentrator line M1-h via the signal line 293.
(steps 919 and 920).

When the control circuit 49 of the interrupt wireless terminal device 4 receives the disconnection signal, it controls the hold circuit 48 to disconnect the wired line 401 from the receiver 43 and the transmitter 45, and outputs a call termination signal as a modulated signal 496. , then control the transmitter 45
Then, the output of the 1g signal 495 from the transmitter 45 is stopped (steps 921 to 923).

The control circuit 24 of the concentrator device 20 receives the end of call signal and the squelch signal via the one side 21h of the concentrator line and the signal line 293, and outputs a disconnection signal when it detects that the transmission signal 495 of the interrupt terminal device has stopped. It stops and outputs a hold release signal (steps 924 and 925).

Upon receiving the hold release signal, the control circuit 49 of the interrupted wireless terminal device 4 controls the hold circuit 48 to disconnect the wired line 401.
Release the connection hold and control the transmitter 45 to send @4
5, the transmission signal 495 is output with the power used during the call, and the hold release response signal is output as the modulation signal 496 (steps 926 and 927).

When the control circuits 2 and 1 of the concentrator device 2 receive the hold release response signal, they stop outputting the hold release signal, control the hold circuit 2 switch circuit 22, and switch the subscriber line Ll and the concentrator line IV1 jl ; M2 H (Steps 928 and 929).

This completes the interruption connection release operation at the end of the emergency call.

Note that as an interference wave detector that detects interference waves by inputting a pre-demodulation signal, a configuration different from the interference wave detector 23 used in the embodiment shown in FIG. 1 has been proposed (
For example, JP-A-58-151735, JP-A-58
-162144, JP-A-58-195333, etc.). A multiple access radio telephone system in which the interference wave detector 23 of the multiple access radio telephone system according to the embodiment shown in FIG. This is an example.

〔Effect of the invention〕

As explained in detail above, the multiple access wireless telephone system of the present invention is a means for interrupting emergency call connection if there is a request for an emergency call even when all of the wireless lines are being used for other calls. Therefore, by using the multiple access wireless telephone system of the present invention, all wireless lines can be used for normal calls and can also respond to requests for emergency calls, so radio waves can be used effectively. There is.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the multiple access wireless telephone system of the present invention, FIG. 2 is a block diagram showing an example of a conventional multiple access wireless telephone system, and FIG. 3 is an embodiment shown in FIG. 1. FIG. 4 is a flowchart showing the interrupt connection operation at the start of an emergency call in the embodiment shown in FIG. 2... Concentrator device, 3...
Base station device, 4... Radio terminal device. Agent Patent Attorney Hara Uchi 8 I″Il (No./

Claims (1)

[Scope of Claims] A concentrator device that concentrates a plurality of subscriber lines connected to an exchange into a plurality of concentration lines smaller than the number of subscriber lines, and a radio base station device that converts the concentration lines into the same number of radio lines. In a multiple access wireless telephone system comprising a plurality of wireless terminal devices wirelessly connected via the wireless line and a telephone connected by wire to each of the wireless terminal devices, the concentrator device includes a first control means. a first hold means for holding the connection of the subscriber line during a call under the control of the controller; a switch means for connecting or disconnecting the subscriber line under the control of the first control means; a plurality of interference detection means that outputs an interference detection signal to the first control means when detecting that there is an interference wave on the corresponding wireless line; The first control means controls the first hold means and the switch means when a detection signal is input, and performs an interrupt connection for an emergency call together with the wireless terminal device via the concentrator line and the wireless line, The wireless terminal device includes a receiving unit that is controlled by a second control unit and outputs an electric field signal that is tuned to one receiving frequency of the wireless line and has a value corresponding to a received electric field strength, and a receiving unit that receives the electric field signal. a transmitting means that is controlled by the second control means and is tuned to one transmission frequency of the wireless line and outputs a transmission signal having a controlled power corresponding to the electric field signal and the normal connection and the emergency connection; emergency signal detection means for outputting an emergency detection signal to the second control means when an emergency signal input from a telephone is detected; and for suspending connection of the wired line during a call under the control of the second control means. a second holding means, when the emergency detection signal is input and there is no vacant line in the wireless line, controlling the transmitting means to output the transmission signal, which is the interference wave, to any one of the wireless lines; The second control unit controls the emergency interrupt connection.
A multiple access wireless telephone system characterized by comprising a control means.