JPH11252632A - Mobile communication system and method for detecting position of mobile radio terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily detect a position of a mobile radio terminal in the mobile communication system adopting an inter-base-station asynchronizing system. SOLUTION: An optional base station 101 obtains a time difference between timing signals 113-115 received from other base stations 102-104 and a timing signal 112 sent from its own base station 101, A mobile radio terminal 105 obtains an arrival time difference among the timing signals 112-115 received from pluralities of the base stations 101-104. A position calculation station 111 calculates position information of the mobile radio terminal 105 based on the time difference, the arrival time difference and the position information of pluralities of the base stations 101-104 decided in advance to easily detect the position of the mobile radio terminal 105 in the mobile communication system adopting an inter-base-station asynchronizing system.

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 for detecting the position of a mobile radio terminal device that performs radio communication via a base station, and a method for detecting the position of a mobile radio terminal. Suitable for use in a May Day (emergency call) system that automatically reports accident information and location in the event of an accident, a wandering elderly man tracking system that allows elderly people with dementia to have a mobile wireless terminal device to find their location, etc. TECHNICAL FIELD The present invention relates to a mobile communication system and a mobile wireless terminal position detecting method.

[0002]

2. Description of the Related Art In recent years, as the number of users of a mobile communication service has increased, it has been required to detect the position of a mobile radio terminal device such as a portable telephone or a PHS terminal.

[0003] For example, suppose that the caller was upset by a sudden accident or fire at the time of calling the numbers 110 and 119, and could not explain his / her exact location by telephone. In such a case, conventionally, when a general household uses a fixed telephone or an emergency telephone on an expressway is used for notification, a telephone station, a control station such as a control station,
By detecting the number of the called phone and notifying the caller's phone number to the other party, the location of the caller can be easily known using the phone number and installation location data registered in advance. Was completed.

However, in the case of a telephone call from a mobile radio terminal, even if the telephone number of the caller is known, the position cannot be known as described above. Proposed and put to practical use.

As one of the methods, there is a method in which a GPS (Global Positioning System) receiver is incorporated in a mobile radio terminal device, and position data of the terminal device calculated by GPS is notified to a control station side. This method has a disadvantage that it is difficult to reduce the size, power consumption, and cost of the mobile wireless terminal device.

For this reason, recently, with respect to a method of detecting the position of a mobile radio terminal, an MTPS which detects a position between a plurality of base stations and the mobile radio terminal without using a GPS receiver or the like has been proposed.
(Mobile Telephone Positioning Systems) technology is being proposed.

[0007] For example, at the ITS'96 World Congress (IT'96 World Congress)
e Location of Mobile Telephones, Chris Dra
ne, Professor, Univ of Tech, Australia), a method to obtain by measuring the reception intensity of the radio wave, a method to obtain by measuring the direction of the radio wave source, and the arrival time of the radio wave A method or the like that is required by this is proposed.

[0008] Among these various methods, one of the methods having high accuracy and relatively easy to realize in existing mobile communication systems is the arrival of a received signal between a plurality of base stations and a mobile radio terminal. There is a method of detecting a position based on a time difference.

As one of the methods, Japanese Patent Application Laid-Open No. 7-181
In the 242 publication, CDMA (Code
In order to measure the position of a mobile wireless terminal device that performs communication in the Division Multiple Access (DIW) method, the mobile wireless terminal device determines the arrival time difference of a signal received from each base station and a reference clock for each base station in advance. It is calculated using the obtained transmission time difference.

[0010] However, CDMA is a system in which transmission information is multiplied by a spreading code and transmitted in frame units, and the receiving side multiplies the same spreading code by a received signal to extract the original transmission information.

A similar method is adopted in Japanese Patent Application Laid-Open No. Hei 7-255079. However, since this method transmits signals synchronized between base stations in accordance with the same master clock, the transmission timing between base stations is shifted. There is no need to consider.

[0012]

However, the above-mentioned conventional Japanese Patent Application Laid-Open Nos. 7-181242 and 7-255079.
The method disclosed in the publication is based on the premise that each base station has the same clock between base stations, that is, a common reference timing. In Japanese Patent Laid-Open Publication No. Hei 7-181242, a mobile communication system is assumed in which a signal is transmitted in synchronization with a base station and a signal is transmitted with a predetermined time offset for each base station with respect to a reference timing. And

Such a system is called an inter-base-station synchronization system, and the United States CDMA system (IS95 system) and the like are known. In the inter-base-station synchronization method, it is necessary to know a high-precision reference timing for each base station. Therefore, each base station has a GPS clock using radio waves from GPS satellites, and time information from the clock is used as a reference timing. It is generally used as That is, each base station needs to be provided with a high-precision clock, and the base station becomes expensive.

In the method disclosed in Japanese Patent Laid-Open No. Hei 7-181242, the position of the mobile radio terminal is calculated on the mobile radio terminal side. This method is effective when the position is to be known on the mobile radio terminal side.

However, in this case, it is necessary to notify the position information of each base station and the transmission time difference between the base stations to the mobile radio terminal side, and for that purpose, a part of the radio signal transmitted from the base station must be notified. Must be assigned to the information. In addition, it is necessary to perform position calculation on the mobile wireless terminal device side, and the mobile wireless terminal device needs to perform CP calculation for calculation.
Since the U operation rate is increased and an extra memory is required, this has been a factor hindering power consumption and miniaturization.

On the other hand, there is no need to have a common reference timing between base stations, and therefore, there is no need to provide a high-precision clock for each base station. Asynchronous schemes have been proposed. In such a system, each base station performs transmission at an arbitrary timing without synchronization with the other base stations.

However, in such an asynchronous system between base stations, the time difference between signals transmitted from each base station cannot be known in advance, and therefore the position of the mobile radio terminal cannot be detected.

An object of the present invention is to provide a mobile communication system and a mobile wireless terminal position detecting method capable of detecting the position of a mobile wireless terminal device in an asynchronous system between base stations.

[0019]

Means for Solving the Problems The present invention has the following arrangement to solve the above-mentioned problems.

The mobile communication system according to the first aspect includes a plurality of timing signal time difference calculating means for calculating a time difference between a timing signal received from another base station device and a timing signal transmitted from the own base station device. A base station device, a mobile radio terminal device having an arrival time difference calculating means for calculating an arrival time difference between timing signals received from the plurality of base station devices, and the plurality of base station devices predetermined with the time difference and the arrival time difference And a position calculating station that calculates the position information of the mobile radio terminal device from the position information.

According to this configuration, the position of the mobile radio terminal can be easily detected in the mobile communication system of the asynchronous system between base stations.

A mobile communication system according to a second aspect of the present invention is the mobile communication system according to the first aspect, wherein the position calculation station device is provided in a control station device that controls a plurality of base station devices. did.

With this configuration, the position of the mobile radio terminal device can be easily detected in the CDMA mobile communication system.

According to a third aspect of the present invention, in the mobile communication system of the first aspect, the position calculating station is provided in a switching center in a fixed telephone network to which a control station is connected. Configuration.

According to this configuration, a wired line or the like connecting the plurality of base station apparatuses and the position calculation station apparatus becomes common, so that the apparatus can be downsized, and the base station position information and the mobile radio terminal apparatus position information can be collectively collected. Management becomes possible.

A mobile communication system according to a fourth aspect of the present invention is the mobile communication system according to any one of the first to third aspects, wherein the timing signals transmitted from a plurality of base station apparatuses are different from each other. The signal is a spectrum-spread signal with a different spreading code for each of the plurality of base station apparatuses or for each of the sectors under the plurality of base stations.

According to this configuration, a wired line or the like for connecting the plurality of base station apparatuses and the position calculation station apparatus becomes common, so that the apparatus can be reduced in size, the base station position information and the mobile wireless terminal apparatus position information can be collectively collected. Management becomes possible.

According to a fifth aspect of the present invention, there is provided a mobile radio terminal position detecting method, comprising the steps of: transmitting a timing signal received from another base station apparatus and a timing signal received from another base station apparatus to the base station apparatus; Determine the time difference between the timing signal and the mobile radio terminal device, determine the arrival time difference between the timing signals received from the plurality of base station devices, the position calculation station device, the time difference and the arrival time difference and the predetermined The position information of the mobile radio terminal device is calculated from the position information of a plurality of base station devices.

According to this method, the position of the mobile radio terminal can be easily detected in the mobile communication system of the asynchronous system between base stations.

According to a sixth aspect of the present invention, there is provided the mobile radio terminal position detecting method according to the fifth aspect, wherein the timing signals transmitted from the plurality of base station apparatuses are transmitted by the plurality of base station apparatuses. The signal is spread spectrum with a different spread code for each or each sector under the plurality of base stations.

According to this method, the position of a mobile radio terminal can be easily detected in a CDMA mobile communication system.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the mobile communication system of the present invention will be specifically described below with reference to the drawings.

(Embodiment) FIG. 1 is a block diagram showing a mobile communication system according to an embodiment of the present invention. FIG.
The mobile communication system according to the present embodiment shown in FIG. 1 includes a plurality of base stations 101, 102, 103, 1 located near each other.
04, a mobile wireless terminal device 105 that performs wireless communication with a plurality of base stations 101 to 104, and a plurality of base stations 101 to 10.
4 is provided with a position calculation station 111 connected by wired lines 106, 107, 108, 109.

Further, 112, 113, 114, 115
Is a timing signal transmitted from the base stations 101 to 104, and 117 is a transmission signal transmitted from the mobile radio terminal device 105, and here indicates a state transmitted to the base station 101. Further, various information described later is transmitted from each of the base stations 101 to 104 to the position calculation station 111.

Next, the internal configuration of each of the base stations 101 to 104 will be described with reference to FIG. However, each of the base stations 101 to 1
04 have the same configuration, and will be described using the base station 101 as a representative.

The base station 101 includes an antenna 200
And a plurality of other base stations 102 to 104 for transmitting the timing signal 112 shown in FIG.
Timing signal receiving means 202 for receiving the timing signals 113 to 115 transmitted from the
115 (see FIG. 1), a timing signal time difference calculating means 203 for calculating the time difference between the timing signals 112 transmitted from the base station 101, and the time difference calculated by the timing signal time difference calculating means 203 in a determined data format. A transmitting means 204 for converting and transmitting the converted data to the position calculating station 111 via the wired line 205;
0, the transmission signal 1 received from the mobile radio terminal 105.
And a signal transfer unit 206 that converts the data 17 into data and transmits the converted data to the position calculation station 111 via the wired line 205.

Next, the internal configuration of the mobile radio terminal 105 will be described with reference to FIG.

The mobile radio terminal device 105 is connected to the antenna 30
0, a timing signal receiving means 301 for receiving the timing signals 112 to 115 transmitted from the respective base stations 101 to 104, and an arrival time difference between the timing signals 112 to 115 received by the timing signal receiving means 301. It comprises an arrival time difference calculating means 302 for calculating, and an arrival time difference transmitting means 303 for transmitting the arrival time difference calculated by the arrival time difference calculating means 302 to a certain base station via the antenna 300.

Next, the internal configuration of the position calculation station 111 is shown in FIG.
This will be described with reference to FIG.

The position calculation station 111 receives the timing signal time difference and the arrival time difference transmitted from each of the base stations 101 to 104 via the wired line 205.
1, a base station position information storage unit 402 for storing position information 402 of each of the base stations 101 to 104, comprising X, Y, and Z coordinate values indicating a position on three-dimensional coordinates;
1. the timing signal time difference and the arrival time difference received at 1;
It comprises a position information calculation means 403 for calculating the position of the mobile radio terminal device 105 from the position information 402 of each of the base stations 101 to 104.

The operation of detecting the position of mobile radio terminal device 105 in the mobile communication system configured as described above will be described.

Each of the base stations 101 to 104 transmits the timing signals 112 to 115 to the timing signal transmitting means 2.
Send by 01. However, each timing signal 112
To 115 are transmitted with transmission power that can be received by another base station nearby.

When the CDMA system is used as the wireless system, for example, the timing signals 112 to 115 are spread and transmitted with different spreading codes predetermined for the respective base stations 101 to 104.

The base station 101 is connected to another base station 102
The timing signal transmitted from 104 is received by the timing signal receiving means 202. Here, in the timing signal receiving means 202 of the base station 101,
Since the base station 101 is spread with a different spreading code for each of the base stations 101 to 104, it is easy to know which base station 102 to 104 the timing signal 113 to 115 belongs to.

Next, the timing signal time difference calculating means 20
3, the timing signals 113-1 for each of the base stations 102-104 received by the timing signal receiving means 202
15 and the time difference between the timing of the timing signal 112 transmitted from the timing signal transmitting means 201 is calculated.

Here, the positions on the three-dimensional coordinates of each of the base stations 101 to 104 are represented by (X1, Y1, Z1) and (X
2, Y2, Z2) (X3, Y3, Z3) (X4, Y4,
Z4), and the propagation times required for the timing signals 113 to 115 transmitted from the base stations 102 to 104 to reach the base station 101 are tb12 and tb12, respectively.
13, tb14. Then, each of the base stations 102 to 104
And the distance to the base station 101 is equal to the product of the propagation time and the speed of the radio wave, that is, the speed of light C, so that the following (1)
Expressions (3) to (3) hold.

(X2-X1) ² + (Y2-Y1) ² + (Z2-Z1) ² = (tb12 × C) ² (1) (X3-X1) ² + (Y3-Y1) ² + (Z3 -Z1) ² = (tb13 × C) ² ... (2) (X4-X1) ² + (Y4-Y1) ² + (Z4-Z1) ² = (tb14 × C) ² ... (3) The times when the stations 101 to 104 transmit the same timing signals 112 to 115 are t1, t2, t3, t
4 is assumed. Here, since the base stations 101 to 104 are not operating in synchronization, t1, t2, t3, and t4 are different times.

Each of the base stations 102 to 104 calculated by the timing signal time difference calculating means 203 of the base station 101
And td12 and td12, respectively.
13, td14, the value is the transmission time lag between the base station 101 and the other base stations 102 to 104, and the propagation time for the timing signals of the other base stations 102 to 104 to reach the base station 101. And are represented by the following equations (4) to (6).

Td12 = (t2 + tb12) -t1 = (t2-t1) + tb12 = t12 + tb12 ... (4) td13 = (t3 + tb13) -t1 = (t3-t1) + tb13 = t13 + tb13 ... (5) td14 = (t4 + tb14) -t1 = (t4-t1) + tb14 = t14 + tb14 (6) Time difference td12, td13, td of this timing signal
14 is transmitted by the transmission means 204 to the position calculation station 111 via the wired line 205.

On the other hand, mobile radio terminal apparatus 105 receives timing signals 112 to 115 transmitted from a plurality of neighboring base stations 101 to 104 by timing signal receiving means 301 via antenna 300. Based on the received timing signals 112 to 115, the arrival time difference calculating means 302 calculates the timing signals 112 to 11
The timing time difference between the five is calculated.

Here, propagation times required for the timing signals 112 to 115 transmitted from the base stations 101 to 104 to reach the mobile radio terminal device 105 are tp1, tp2, tp3, and tp4, respectively. In this case, since the distance between each of the base stations 101 to 104 and the mobile radio terminal device 105 is equal to the product of the propagation time and the speed of the radio wave, that is, the speed of light C, the position of the mobile radio terminal device 105 is (X, Y , Z), the following equations (7) to (10) hold.

(X−X1) ² + (Y−Y1) ² + (Z−Z1) ² = (tp1 × C) ² (7) (X−X2) ² + (Y−Y2) ² + (Z -Z2) ² = (tp2 × C) ² … (8) (X-X3) ² + (Y−Y3) ² + (Z-Z3) ² = (tp3 × C) ² … (9) (X-X4 ) ² + (Y−Y 4) ² + (Z−Z 4) ² = (tp 4 × C) ² (10) Here, each timing signal 113-calculated by the arrival time difference calculating means 302 of the mobile radio terminal apparatus 105. Assuming that the time difference of 115 is tp12, tp13, tp14, the following equations (11) to (13) hold.

Tp12 = (t2 + tp2)-(t1 + tp1) = t12 + (tp2-tp1) (11) tp13 = (t3 + tp3)-(t1 + tp1) = t13 + (tp3-tp1) (12) Tp14 = (t4 + tp4)-(t1 + tp1) = t14 + (tp4-tp1) (13) Arrival time difference transmitting means 302 of the mobile wireless terminal device 105
Are the time differences tp12, tp13, tp of the timing signals.
14 is transmitted to the base station 101 using a radio signal.

The base station 101 determines the time difference tp12, tp13, tp1 of the timing signal transmitted as a radio signal.
4 is transferred to the position calculation station 111 via the wired line 205 after performing data conversion or the like by the signal transfer means 206.

The position calculation station 111 transmits the time differences td12, td13, and td14 of the timing signals calculated by the base station 101 and the timing signals calculated by the mobile radio terminal device 105, which are transmitted via the wired line 205. The time differences tp12, tp13, and tp14 are received by the receiving means 401 shown in FIG.

Next, the position information calculating means 403 calculates each of the base stations 10 stored in the base station position information storing means 402.
1 to 104, that is, (X1, Y1, Z
1), (X2, Y2, Z2), (X3, Y3, Z3),
The values of (X4, Y4, Z4) and td12, td13, td14 and tp12, tp received by the receiving means 401
13 and tp14 to simultaneously solve the above equations (1) to (13) to solve the problem.
The values of X, Y, and Z, which are the positions of, are obtained.

Here, all the equations are obtained from the equations (1) to (13).
And all unknowns are X, Y, Z and tb
12, tb13, tb14 and t12, t13, t14
And tp1, tp2, tp3, and tp4, and all these unknowns can be obtained.

In this example, the number of base stations receiving the timing signal is four. However, if five or more base stations can be used, the error is further reduced by solving the above equation using the least square method or the like. be able to.

Further, in an area where there is no undulation and the altitude is known in advance, the value of the Z coordinate is known, and the position can be calculated using three base stations.

As described above, according to the embodiment, even in a base station 101-104 asynchronous mobile communication system having no common clock between base stations 101-104 and having no reference timing. By calculating the time difference between the timing signals 112 to 115 between the base stations 101 to 104 and using the time difference between the timing signals 112 to 115 from the plurality of base stations 101 to 104 calculated by the mobile wireless terminal device 105, the mobile wireless terminal device 105 is used. Can be easily calculated.

The position calculation is performed by the mobile radio terminal device 105.
Therefore, there is an advantage that the processing in the mobile wireless terminal device 105 is simplified because the processing is performed by the position calculation station 111 without performing the processing.

In the above embodiment, the position calculation station 1
11 are provided independently, but in an actual mobile communication system, functions equivalent to those of a base station control station that controls a plurality of base stations 101 to 104 and an exchange control station that is a gateway to a fixed telephone network are provided. May be mounted. In this case, a wired line or the like is used in common, and there is an advantage that the device can be downsized and the location information of the base station and the location information of the mobile wireless terminal device can be collectively managed.

[0063]

As is apparent from the above description, according to the present invention, the position of a mobile radio terminal can be easily detected in a mobile communication system of an asynchronous system between base stations.

[Brief description of the drawings]

FIG. 1 is a block diagram of a mobile communication system according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram of a base station in the mobile communication system according to the embodiment.

FIG. 3 is a block diagram of a mobile wireless terminal device in the mobile communication system according to the embodiment.

FIG. 4 is a block diagram of a base station in the mobile communication system of the embodiment.

[Explanation of symbols]

101 to 104 Base station 105 Mobile radio terminal device 111 Position calculation station 112 to 115 Timing signal 203 Timing signal time difference calculation means 302 Arrival time difference calculation means 402 Base station position information storage means 403 Position information calculation means

Claims (6)

[Claims] 1. A plurality of base station apparatuses having timing signal time difference calculating means for calculating a time difference between a timing signal received from another base station apparatus and a timing signal transmitted from the base station apparatus; A mobile radio terminal device having an arrival time difference calculating means for obtaining an arrival time difference between timing signals received from a station device, and the mobile radio terminal based on the time difference and the arrival time difference and predetermined position information of the plurality of base station devices. A mobile communication system, comprising: a position calculation station device that calculates position information of the device. 2. The mobile communication system according to claim 1, wherein the position calculation station device is provided in a control station device that controls a plurality of base station devices. 3. The mobile communication system according to claim 1, wherein the position calculation station device is provided in an exchange device in a fixed telephone network to which the control station device is connected. 4. A timing signal transmitted from a plurality of base station apparatuses is a signal spread spectrum with a different spreading code for each of the plurality of base station apparatuses or for each sector under the plurality of base stations. The mobile communication system according to any one of claims 1 to 3, wherein: 5. A mobile radio terminal device, wherein at any one of a plurality of base station devices, a time difference between a timing signal received from another base station device and a timing signal transmitted from its own base station device is determined. Calculating the arrival time difference between the timing signals received from the plurality of base station devices, and calculating the mobile radio based on the time difference and the arrival time difference and the predetermined position information of the plurality of base station devices at the position calculation station device. A mobile wireless terminal position detecting method in a mobile communication system, wherein position information of a terminal device is calculated. 6. A timing signal transmitted from a plurality of base station apparatuses is a signal that is spread spectrum with a different spreading code for each of the plurality of base station apparatuses or for each sector under the plurality of base stations. The mobile wireless terminal position detecting method according to claim 5, wherein