JP2599723B2 - Mobile communication system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a mobile communication system, particularly to a mobile telephone system.

(Prior Art) A conventional car phone system uses a car phone,
If a car enters a tunnel where radio waves cannot reach,
The line that was connected at the exchange was released. For this reason, there is a method of installing a leaky coaxial antenna in a tunnel where radio waves do not reach and relaying radio waves from a base station and a mobile phone.

However, this method is expensive to install, and it is not possible to install a leaky coaxial antenna in every tunnel.

(Problems to be Solved by the Invention) In a conventional car telephone, even if another radio wave is called from a public telephone waveform car radio wave and connected, for example, the car enters the tunnel almost at the same time and the line is opened. It costs a lot of money before the call starts (actually 100
Was also wasted. In other words, pay phone charges are high for payphone type
Since the call is made while inserting the yen, the loss of the charge when the call is interrupted is large, and the trouble of re-calling is troublesome.

(Means and Actions for Solving the Problems) The present invention solves the conventional drawbacks and does not immediately release the line even in the case of a tunnel that is not very long, even if the radio wave from the other party during the call weakens. The line is maintained in a hold state for a time, and the call is resumed when the radio wave becomes strong again within a predetermined time.

In order to achieve such an object, the present invention relates to a mobile communication system in which a mobile station communicates with a base station by radio, and the mobile station communicates with a partner device via a line connected to the base station. A base station and a mobile station each have a reception electric field level detection unit, and in a state where the end signal from the base station or the mobile unit is not detected, when the level detection unit detects a decrease in the level of the reception electric field strength, a predetermined level is set. Within a period of time, the mobile station and the base station keep transmitting a carrier wave to hold the wireless line, and put the telephone line connected to the base station in a talking state on hold, and furthermore, the mobile station and the telephone of the partner device And a control for generating a hold tone instead of a voice signal.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 2 is a diagram schematically showing a mobile communication system,
Telephone 12 connected to exchange 13 by telephone line 11
The call signal from the exchange 13, the radio network controller 14,
The signal is transmitted from the base station antenna 16 to the mobile device 20 through the radio base station 15. This signal is received by the mobile device antenna 26 of the mobile device 20, and is received by the mobile phone 22 via the mobile device transceiver 27.

The signal from the mobile station 20 is received by the base station antenna 16 via the mobile station transceiver 27 and the mobile station antenna 26, and is transmitted through the radio base station 15, the radio network controller 14, the switching office 13, and the telephone network 11 to the telephone. Arrived at 12.

The exchange 13 described in this embodiment is a combination of a general exchange and a mobile telephone exchange. In addition, this mobile communication system generally adopts a small zone system as shown in FIG.

FIG. 3 is a block diagram of a radio base station according to one embodiment of the present invention. The radio base station 15 connected to the radio network controller 14 includes a base station receiving unit 37 and a base station transmitting unit 47,
The input of the receiving unit 37 and the output of the transmitting unit 47 are connected to the base station antenna 16 by the duplexer 38, and transmit and receive signals to and from the mobile device. The output of the receiving unit 37 is divided into a voice channel 32 and a data channel 33, and the base station control unit
It is processed by 31 and sent to the radio network controller 14. The reception electric field level is input to the control unit 31 detected by the level detector 40 that detects the signal level of the intermediate frequency output of the reception unit 37.

The signal from the radio network controller 14 is an audio signal or data signal from the audio signal unit 42 processed by the base station controller 31.
The data signal of 43 is transmitted to the transmission unit 47, and transmitted from the antenna 16 to the mobile device via the duplexer 38.

FIG. 4 is a block diagram of a mobile device according to one embodiment of the present invention. The mobile transceiver 27 includes a mobile transmitter 53 and a mobile receiver 57. The output of the transmitter 53 and the input of the receiver 57 are connected to the mobile antenna 26 by the duplexer 58, and are connected to the base station or the base station. To send and receive signals from The output of the receiving unit 57 is processed by the mobile unit control unit 51, and
And the signal level of the receiving unit 57 is detected by a level detector.
Detected by 60 and input to mobile unit control unit 51.

The signal from the mobile telephone 22 is processed by the mobile control unit 51 and sent to the transmission unit 53. The signal is transmitted from the antenna 26 to the radio base station 15 via the duplexer 58.

Here, the operation of calling a mobile device from the telephone 12 through the base station will be described.

The radio network controller 14 receiving the call of the mobile station from the calling telephone 12 via the exchange 13 modulates the number data of the called mobile station 20 by the control channel from the radio base station 15 which has registered the call. Send out.

When the mobile station 20 receives its calling number, it sends out a response signal through the control channel. The wireless base station 15 adds the received electric field strength level detection output detected by the level detector 40 to the response signal and sends the response signal to the radio network controller 14. The radio network controller 14 detects an empty communication channel and sends a communication channel designation signal to the mobile device 20 and the exchange 13. Upon receiving this signal, the mobile device 20 controls the frequency synthesizer 59 to enable transmission and reception of the specified communication channel.

The radio network controller 14 sends the mobile station call signal on the call channel, and sends a ring back tone from the exchange 13 to the calling telephone 12. Mobile device operator is mobile phone
When the handset 22 is picked up, the response signal is transmitted to the exchange 13 via the radio network controller 14. The exchange 13 connects the calling telephone 12 and the mobile device 20 to each other,
20 and the calling telephone 12 enter the talking state. When the call ends and the handset of the mobile telephone 22 is picked up, a call termination signal from the mobile device 20 is transmitted to the radio network controller 14 via the radio base station 15 via the radio channel. The radio network controller 14 detects the end signal and sends the end data to the exchange 13. The exchange 13 receives the call termination data, releases the line, and ends the call state.

The following describes the operation performed when a vehicle equipped with a mobile device enters a tunnel where no measures are taken against dead zones during a call.

In the mobile device 20, the level of the intermediate frequency signal output of the receiving unit 57 is detected by the level detector 60, and a decrease in the level is detected. The mobile unit control unit 51 of the mobile unit 20 transmits a hold tone to the handset of the mobile telephone 22 whose handset is up, and continuously transmits a carrier wave from the transmission unit 53 through the communication channel.

On the other hand, the level of the intermediate frequency output of the receiving unit 37 of the wireless base station 15 is detected by the level detector 40 to detect a decrease in the level of the received electric field. Upon receiving this detection output, the radio network controller 14 continues to transmit a carrier wave and, at the same time,
Send a hold tone to 12. Here, since both the mobile station and the base station continue to transmit a carrier wave, the wireless channel is maintained.

When the car exits the tunnel, the level detector 60 of the mobile device 20 detects a high received electric field level, and the mobile device controller 51
The mobile device control unit 51 stops transmitting the hold sound and sets a state in which communication with the wireless base station 15 is possible.

On the other hand, the wireless base station 15 similarly detects that the level detecting section 40 is receiving the increased received electric field strength again, and sends a detection output to the wireless network control station 14. Radio circuit control station
14 stops sending the hold tone to the calling telephone set 12 via the exchange 13 so that the communication with the mobile unit 20 can be resumed.

However, when the hold state becomes longer than a predetermined time, such as when the tunnel is long, the mobile device 20 detects that a certain time has elapsed by the mobile device control unit 51, and sends a busy tone to the mobile phone 22. I do. Thereafter, the frequency synthesizer 59 is controlled to enable transmission / reception of the control channel, and to enter a standby state. The radio network controller 14 also detects that a predetermined time has elapsed, and sends a line release control signal to the exchange 13. The exchange 13 receives this signal and sends a busy tone to the calling telephone 12.

 The call is disconnected as described above.

In this way, even if the call from the mobile device 20 is interrupted in the middle of a short time, the line is held without disconnecting the call immediately, and when there is no obstacle, the call can be immediately returned to the call state.

The flow of these operations is shown by the control flow of the radio base station in FIG.

Also, in this method, when the mobile station 20 moves to another call zone while being on hold, the line between the mobile device 20 and the calling telephone 12 is released.

The operation after transmission from the mobile device 20 is the same as described above.

The present invention is not limited to the embodiments described above, and many modifications are possible.

(Effects) As described above, according to the present invention, even if the communication condition is deteriorated for a short time, the call is put on hold during that time, and the communication can be resumed immediately when the condition returns to the original state, so that a user-friendly mobile communication system can be realized.

[Brief description of the drawings]

FIG. 1 is a control flow chart on the radio base station side of the present invention. FIG. 2 is a schematic diagram of a mobile communication system. FIG. 3 is a block diagram of a radio base station according to one embodiment of the present invention. FIG. 4 is a block diagram of a mobile device according to one embodiment of the present invention. FIG. 5 is a diagram showing a call zone. 11 ... Telephone line, 12 ... Telephone 13 ... Switching station, 14 ... Radio circuit control station 15 ... Radio base station, 16 ... Base station antenna 20 ... Mobile unit, 22 ... Mobile unit telephone 26 ... … Mobile unit antenna, 27… mobile unit transceiver 31… base station control unit 32… voice channel 33… data channel 37… base station receiving unit 38… duplexer 39… frequency synthesizer 40 … Level detector, 42… Audio signal part 43… Data signal part, 47… Base station transmitting part 51… Mobile station control part, 53… Mobile station transmitting part 57… Mobile station receiving part, 58 …… Duplicator 59 …… Frequency synthesizer 60 …… Level detector

Claims (1)

(57) [Claims] 1. A wireless communication between a mobile station and a base station,
In a mobile communication system in which a mobile station communicates with a partner device via a line connected to a base station, the base station and the mobile station each include a reception electric field level detection unit, and a call termination signal from the base station or the mobile station. When the level detection unit detects a decrease in the received electric field strength without detecting the signal, the mobile station and the base station continue to transmit the carrier wave within a predetermined time, hold the wireless line, and connect to the base station. A mobile communication system comprising: placing a telephone line in a call state being held in a hold state; and performing control to generate a hold sound in place of a voice signal in a mobile device and a telephone of a partner device.