JPH07284147A - Mobile communication system - Google Patents

Abstract

PURPOSE:To quickly measure a position of a mobile station with high precision on emergency. CONSTITUTION:In the mobile communication system where a communication channel is connected between a mobile station 4 and a contact destination 7 specified in advance via a base station 2 and an exchange control station 3 on emergency and position information of the mobile station is informed to the contact destination simultaneously, an emergency communication channel 6 in common to the service area is provided as a radio channel between the mobile station 4 and the base station 2, each base station is provided with a timing detection means 11 receiving the transmission from the mobile station through the use of emergency communication channel to detect the reception timing, the exchange control station 3 is provided with a position detection means 8 detecting the position of the mobile station based on data from the timing detection means of each base station 2. When the mobile station 4 makes emergency communication, plural base stations 2 receives the communication to detect the reception timing 12 and to inform it to the exchange control station 3. The position detection means 8 detects the position of the mobile station 4 based on the deviation in the reception timing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system such as a digital car phone and a mobile phone, and more particularly to a mobile communication system which enables quick emergency communication.

[0002]

2. Description of the Related Art In a conventional mobile communication system, as shown in FIG. 4, a cell having a large number of service areas for communication is used.
The location registration area 19 is composed of a plurality of cells 18. In addition, a base station 20 is installed in each cell for each station and communicates with a mobile station 21 located in the cell via a wireless line. All the base stations are connected to the switching control station 22, and the switching control station 22 further connects to the fixed telephone network 23.
Connected to.

When the power of the mobile station 21 is turned on, the mobile station identification number and the position information in units of the position registration area 19 are transmitted to the exchange control station 22 via the base station 20 through the control channel to perform the position registration. , The mobile station 21 enters the standby state. Also, when the mobile station 21 crosses the location registration area 19, the location information is rewritten to the exchange control station 22 by the same operation.

When a mobile station 21 in the standby state receives an incoming call from the fixed telephone network 23, the exchange control station 22 causes all the base stations 20 in the location registration area 19 obtained from the location information of the mobile station 21.
Then, the paging signal is transmitted through the control channel.
When the mobile station 21 responds to the paging signal, the switching control station 22 performs line connection processing, identifies the base station 20 closest to the mobile station 21, and starts communication through the communication channel.

On the other hand, when originating from the mobile station 21, the mobile station 21 sends out a calling signal, and the exchange control station via each base station 20.
22 receives. The switching control station 22 performs line connection processing,
The base station 20 closest to the mobile station 21 is specified, and then the fixed telephone network 23 is connected.

In such mobile communication, Japanese Patent Laid-Open No. 4-360328 discloses a system for performing emergency communication from a mobile station to a notification destination such as a police station or a fire station.

In this system, the mobile station is provided with an operation button for outputting a predetermined request signal, and each base station is provided with a circuit for measuring the distance to the mobile station. When the caller presses the operation button of the mobile station, emergency call information is transmitted from the mobile station, and this information is received by the base station of the cell in which the mobile station is located. When the base station recognizes from the received information that it is an emergency call, it returns information such as a call response and instruction to the mobile station that made the emergency call, and at the same time, the surrounding base stations. To the mobile station are notified of the information necessary for measuring the distance to the mobile station, such as the occurrence of the emergency call, the transmission frequency of the mobile station making the emergency call, the identification code of the mobile station, and the like.

The mobile station further responds to the return from the base station (base station in charge), and each base station communicates with the base station in charge → the mobile station → the base station in charge and Based on the time difference between receiving the bursts sent from each of the mobile stations and the time until the base station in charge receives the burst transmitted by the mobile station, which is notified from the base station in charge, the mobile station and its own station Measure the distance. The distance measured by each base station is collected by the exchange control station, and the exchange control station measures the position of the mobile station from these distances, and notifies the emergency notification destination of the occurrence of the emergency and the position determination of the mobile station. Notify location and.

[0009]

However, this emergency communication system in mobile communication has the drawback that each base station must be equipped with a distance measuring circuit, and
Because distance measurement is performed based on the burst transmitted during the communication between the base station and the mobile station, or because it is necessary to receive information from the responsible base station for distance measurement at each base station, etc. In addition, there is a problem that the positioning of the position of the mobile station is delayed.

The present invention solves these conventional problems, and an object of the present invention is to provide a mobile communication system capable of quickly measuring the position of a mobile station with high accuracy in an emergency.

[0011]

Therefore, in the present invention, in an emergency, a call line is connected between a mobile station and a contact specified in advance via a base station and a switching control station, and at the same time, the mobile station is connected. In the mobile communication system that notifies the location information of this to the contact point, an emergency communication channel commonly used in the service area is provided as a wireless line between the mobile station and the base station, and the mobile station is moved to each base station. The switching control station is provided with timing detection means for detecting the reception timing by receiving the transmission performed by the station using the emergency communication channel, and the position of the mobile station based on the data received from the timing detection means of each base station. A position detecting means for detecting is detected.

Further, the mobile station and the base station are connected to each other by a radio line of a code division multiple access system, and an emergency spreading code commonly used in the service area is provided as an emergency communication channel.

[0013]

Therefore, when the mobile station makes an emergency communication using the emergency communication channel, the plurality of base stations intercept the communication of the channel, detect the reception timing, and notify the position detecting means of the exchange control station. To do. This reception timing is
There is a slight deviation according to the distance between the mobile station and each base station. The position detecting means detects the position of the mobile station based on the deviation of the reception timing.

In the mobile communication system using the code division multiple access system, an emergency spreading code is set as an emergency communication channel and is commonly used in the service area.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a mobile communication system in an embodiment of the present invention uses a normal communication channel and a control channel 5 as a wireless line between a mobile station 4 and a base station 2.
In addition, an emergency communication channel 6 common to all base stations is provided. Each base station 2 is additionally provided with a timing detection device 11 for detecting the reception timing of a signal transmitted from the mobile station 4 through the emergency communication channel 6. The exchange control station 3 is connected to the fixed telephone network 14 in the case of communication using the general communication line 5, and in the case of emergency communication using the channel 6 for emergency communication, the exchange control station 3 in advance such as police or a security company. It is directly connected to the communication device 9 of the specified destination 7. The exchange control station 3 is provided with a position detecting device 8 for detecting the position of the moving body 4 based on the information sent from each timing detecting device 11, and the position detecting device 8 detects the position. The position information is output to the position display device 10 of the emergency partner 7. In addition, the service area is divided into a large number of cells 1 and the configurations of the base station 2 and the switching control station 3 are the same as those of the conventional example.

In this system, when the mobile station 4 performs a normal communication procedure, the mobile station 4 passes through the base station 2 and the switching control station 3 as in the conventional example. Connected to 14. On the other hand, in an emergency, if the emergency switch of the mobile station 4 is operated, the channel is switched to the emergency communication channel 6 to make a call. The exchange control station 3 is connected to each base station 2
When a call signal from the emergency communication channel 6 is received via the line, a line connection process for directly connecting to the emergency contact 7 such as the police or security company is performed to establish a call state between the mobile station 4 and the emergency contact 7. enter.

In the call state, as shown in FIG. 2, the mobile station 4 inserts not only the voice signal 16 but also the timing detection signal 17 into the voice signal through the emergency communication channel 15 and sends it out. This timing detection signal 17 is received by a plurality of base stations 2, and each base station 2 detects the reception timing 12 of the timing detection signal 17 by the timing detection device 11 and detects the position of the exchange control station 3. Send to device 8.

The reception timing is deviated according to the distance between the mobile station 4 and each base station 2. The position detecting device 8 obtains the relative distance of the mobile station 4 from each base station 2 due to the deviation of the reception timing of each base station, and the position of the mobile station 4 is obtained using this relative distance. The location information 13 is sent to the emergency contact 7. At the emergency contact 7, the position information received by the mobile station 4 is displayed at the same time as the communication with the communication device 9 is performed using the position display device 10.

When this mobile communication system uses a code division multiple access (CDMA) system by direct spreading as an access system, a common emergency spreading code is prepared in the service area for emergency communication.

In this code division multiple access method, the transmitting side multiplies the information data to be transmitted by a code for distinguishing the channel, spreads the signal in a wide band, and transmits the signal. On the other hand, on the receiving side, the received information is reproduced by multiplying (despreading) the received signal by a code synchronized with the code multiplied on the transmitting side.

In this mobile communication system, each mobile station 4 is assigned a unique spreading code within the cell, and the mobile station 4 uses this spreading code to transmit information data by frequency in normal communication. Spread on the axis and transmit. On the other hand, in an emergency, similar transmission is performed using the emergency spreading code. The plurality of base stations 2 receive this and detect the timing of the spread code received by correlating with the emergency spread code used in the received signal,
The reception timing is transmitted to the position detecting device 8 of the exchange control station 3. FIG. 3 shows the received signal 20 after correlation. A sharp peak 22 appears in the cycle 21 of the spreading code, and the reception timing can be detected by detecting this. The position detecting device 8 detects the position of the mobile station by using the deviation of the reception timing of each base station, and transmits the obtained position information 13 to the emergency contact 7. When the emergency spreading code is used, it is possible to facilitate reception at a plurality of base stations by increasing the transmission power of the mobile station more than usual.

[0022]

As is apparent from the above description of the embodiments, in the mobile communication system of the present invention, a common emergency communication channel is provided in the service area, and the mobile station transmits using this emergency communication channel. At that time, the position of the mobile station is specified based on the deviation of the reception timing detected by the plurality of base stations. Therefore, it is not necessary to provide a measurement circuit in each of the base stations, and the position of the mobile station in an emergency can be specified quickly.

In addition, in the code division multiple access system, each base station can detect the reception timing from the call of the mobile station using the emergency spreading code, so that the timing can be detected during the emergency call. There is no need to insert a signal for detection.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a mobile communication system according to an embodiment of the present invention,

FIG. 2 is an example of an emergency communication channel used in the mobile communication system of the embodiment,

FIG. 3 is a diagram showing peaks of a received signal for measuring a reception timing in a communication system of an embodiment adopting a code division multiple access system;

FIG. 4 is a conceptual diagram of a conventional mobile communication system.

[Explanation of Codes] 1, 18 Cell 2, 20 Base Station 3, 22 Switching Control Station 4, 21 Mobile Station 5 Normal Control / Communication Channel 6 Emergency Communication Channel 7 Emergency Contact 8 Position Detection Device 9 Communication Device 10 Position display device 11 Timing detection device 12 Reception timing information 13 Position information 14, 23 Fixed telephone network

Claims (2)

[Claims] 1. In an emergency, a call line is connected between a mobile station and a contact specified in advance via a base station and a switching control station, and at the same time, the location information of the mobile station is notified to the contact. In a mobile communication system, an emergency communication channel commonly used in the service area is provided as a wireless line between the mobile station and the base station, and the mobile station uses the emergency communication channel for each base station. The switching control station is provided with timing detecting means for receiving the transmission to be performed and detecting the reception timing, and the switching control station is provided with position detecting means for detecting the position of the mobile station based on the data received from the timing detecting means of each base station. A mobile communication system characterized by the above. 2. The mobile station and the base station are connected to each other by a radio line based on a code division multiple access system, and an emergency spreading code commonly used in a service area is provided as the emergency communication channel. The mobile communication system according to claim 1, wherein: