KR100567489B1 - Terminal Location Estimation Method in Mobile Communication System - Google Patents

Abstract

The present invention relates to a method for estimating the position of a terminal so that the position of the terminal can be more accurately estimated by effectively compensating the delay delay effect using the base station position information and the repeater information in a mobile communication system. A first step of estimating a virtual position of the terminal using a coordinate value of each signal source and a time difference of arrival of each signal by considering each base station as a signal source after the terminal receives a signal transmitted from a base station or a repeater; Determining whether the received signal has passed through the repeater, and if the received signal has passed through the repeater, selecting the repeater; And a third step of estimating the position of the terminal using the coordinate values of each signal source and the arrival time difference of each signal after compensating the delay effect of the selected repeater by considering the selected repeater as a signal source. It is an invention to overcome the position error caused by the delay delay problem, and to estimate the position of the terminal more accurately by using the repeater information to estimate the position of the terminal without the repeater effect.

Terminal, base station, repeater, location estimation

Description

Terminal location estimation method in mobile communication system {METHOD FOR ESTIMATING LOCATION OF TERMINAL IN MOBILE COMMUNICATION SYSTEM}

1 is a diagram schematically illustrating an overall process of estimating the position of a terminal using repeater information in a mobile communication system;

2 is a diagram illustrating a location estimation method of a terminal in a TDOA method;

3 is a diagram showing respective distances in the position tracking system according to the first embodiment of the present invention;

4 is an orthogonality diagram of H-GX and GX vectors for minimizing errors in position calculation in the first embodiment;

5 is a flowchart for explaining an estimation method according to a second embodiment of the present invention;

6 is a diagram illustrating an error ellipse when there is no repeater delay;

7 is a diagram illustrating an error ellipse extended due to a relay delay;

8 is a diagram illustrating an error ellipse excluding a repeater delay effect according to the second embodiment;

9 is a diagram of an error ellipse determined at the time of position calculation according to the second embodiment;

The present invention relates to a terminal location estimation method for estimating the location of a mobile communication terminal (hereinafter referred to as a 'terminal') using base station location information and repeater information in a mobile communication system. If the error occurred when calculating the location with the base station information exceeds the standard limit error, it is judged to be a delay effect by the repeater.Replace the base station information (coordinate value of the base station) with the repeater value to minimize the error ellipse. Value, the time delay value of the repeater) and the terminal location estimation method in a mobile communication system to effectively compensate for the delay delay effect to estimate the position of the terminal more accurately.

In general, a repeater does not have a call capacity by itself, operates in a base station dependent manner, and plays a role of linearly relaying a change in base station output without any damage. And the signal reaching the user and the base station through the hardware time delay of the repeater is the same as the effect that the signal is transmitted from the base station or the user of a very long distance. Therefore, various window size parameters of the user and the base station should be appropriately set to compensate for propagation time delay in the distance, so that initial search of various signals (pilot, access, reverse call channel) is possible.

The hardware time delay of the repeater is mostly caused by surface acoustic wave (SAW) filter used in the repeater RF circuit, and depending on the characteristics of the surface acoustic wave filter, the time delay of 5-12μsec each occurs. In this case (low input, high output), the spurious signal of the transmit output becomes difficult to satisfy the propagation law, so a sharper surface acoustic wave filter is used. In this case, only one surface acoustic wave filter generates a time delay of about 10 μsec.

Due to this problem, it is necessary to clean up the neighbor list of the base station and the base stations around the repeater interworking with the repeater.If the base station is the one station such as the optical repeater, the list of neighbors is relatively simple. In the case of a repeater for receiving a plurality of base stations in the city center. In this case, the neighbor PN offset, which must be newly added to the repeater and the base station neighbor base station, is required a lot, which causes difficulty in processing the neighbor list. In the current mobile communication network, even if the state of the aerial is analyzed to solve the problem of the repeater, it is impossible to confirm whether the signal passes through the repeater.

Therefore, the time delay of the repeater when determining the position of the terminal serves as a significant factor to include a large error.

Korean Patent Application No. 10-1999-0049754 "Terminal Location Estimation Method in Mobile Communication System" can identify the location of a mobile terminal by making a database of the strength and regional characteristics of the multipath signal for the pilot signal received from the mobile terminal. It is open to the public.

Korean Patent Application No. 10-2001-0012148 "Terminal location tracking system and method of code division multiple access method" excludes pilot signals transmitted from repeaters and uses only pilot signals transmitted from at least three base stations located around the terminals. The method of calculating the position of the terminal is disclosed.

Korean Patent Application No. 10-2001-0030290 "Location tracking system using electric field and radio wave map" uses the electric field intensity of radio waves transmitted and received by base stations located in each region and radio maps previously identified for each base station. A system for identifying a location of a mobile terminal and providing the identified location of the mobile terminal through the Internet is disclosed.

The above-described prior arts only present methods for estimating the position of the terminal only in the relationship between the terminal and the base station, and do not mention a method of estimating the position of the terminal using a repeater directly with respect to a signal via the repeater. .

The present invention has been invented in view of the above circumstances, and in order to increase the accuracy of the estimated position of the terminal generated when the signal received at the terminal passes through the repeater, it is determined whether the signal received at the terminal has passed through the repeater. In case of passing through a repeater, a method for estimating the position of a terminal in a mobile communication system that selects the transited transiter and estimates the position of the terminal by considering the selected repeater as a signal source. It is an object of the invention to provide.

In order to achieve the above object, the present invention provides a method for estimating the position of a terminal in a mobile communication system using base station information and repeater information: the terminal receives a signal transmitted from the base station or repeater A first step of estimating a virtual position of the terminal using the coordinate values of each signal source and the time difference of arrival of each signal by considering each base station as a signal source; Determining whether the received signal has passed through the repeater, and if the received signal has passed through the repeater, selecting the repeater through the repeater; Considering the selected repeater as a signal source, compensating a delay effect of the selected repeater, and estimating the position of the terminal using a difference between the coordinate values of each signal source and the arrival time of each signal; Characterized in that comprises a.

In the above, the second step is an R value that is the average of the distance between the virtual position of the terminal and the coordinate value of each signal source, the distance between the virtual position of the terminal and the coordinate value of each signal source and the time difference of arrival of each signal. After calculating the W value that is the average of the difference between the measured distance of the terminal and each signal source calculated from the above, if the W value is greater than the R value, it is determined that the signal via the repeater, and if it is determined that the signal via the repeater Considering the repeater as a signal source, after estimating the position of the terminal to calculate the R value and the W value, it is preferable to select the repeater whose W value is less than the R value as the repeater via the received signal.

In the second step, the error limit of the position error generated by the delay delay effect is set, and then the virtual position of the terminal is compared with the error limit to determine whether the signal passes through the repeater. In the case where it is determined that the signal is passed, it is preferable to consider each repeater as a signal source to obtain an error ellipse, and to select a repeater that generates a minimum error ellipse as a repeater received by the received signal.

Hereinafter, the configuration and operation of the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 schematically illustrates the overall process of estimating the position of a terminal using repeater information in a mobile communication system.

2 illustrates a position estimation method of a terminal in the TDOA method.

First, the first embodiment will be described with reference to FIG. 3.

The location of the terminal is obtained as follows using the distance difference caused by the time difference between the terminal and the base station.

When the measured distance between mobile phone and base station is 'r', the distance difference between '0' base station and 'i' base station is

(Equation 1)

: 측정값

: Measures

Where c is the speed of light and d _io is the propagation time difference between the i-th base station and the 0-th base station.

The distance equation of the two-dimensional plane between each base station and the terminal is as follows (Equation 2).

(Equation 2)

(Equation 3)

Substituting r _i = r _io + r _o in (Equation 1) into (Equation 2) above

(Equation 4)

here

(Eq. 5)

here

Substituting Equation 5 into Equation 4,

If you unfold it

Here, if the right term is defined as h _i and the matrix is arranged as a matrix, the following determinant is displayed.

(Equation 6)

The above equation can be expressed as (Equation 7).

(Eq. 7)

G X = H

here,

Considering the error in the above equation,

(Eq. 8)

GX = H-ε

(Eq. 9)

ε = H-GX

Using the least square method to find the solution that minimizes the error,

(Eq. 10)

The graphical representation of H-GX is shown in FIG. 4.

Since the minimum H-GX is orthogonal to the G vector, the dot product of the two vectors becomes '0'.

So H-GX ┴G-> (H-GX) G = 0

This can be summarized as the equation (X) below.

(Eq. 11)

X = (x _p , y _p ): the location of the terminal

Accordingly, the distance between each base station and the terminal is calculated by calculating the actual distance r obtained using the calculated coordinates of the mobile phone and the coordinates between the base stations and the measured distance P measured in the mobile phone (hereinafter referred to as a rate).

                     :

Therefore, when R / S ≤ W / S, it is determined that the repeater time delay effect is a signal through the repeater for the signal source having the largest "real-side error", and the signal source of this signal is changed from the base station to the repeater. That is, change the position of the repeater, change the signal generation time to the signal generated after the delay effect of the repeater itself and the propagation time from the base station to the repeater, and then calculate it again by the position calculator to calculate R / S> W / By finding the repeater information to be S, it is possible to estimate the position value of the terminal more accurately.

In another embodiment of the present invention, a method of using a position error variance value of a terminal calculated in a mobile communication system is proposed as a method of using repeater information forming a minimum error ellipse.

The position estimation method of the terminal using the position error variance value of the terminal of the present embodiment proceeds as shown in the flowchart of FIG. 5.

Figure 6 shows a diagram of an error ellipse when there is no repeater delay, Figure 7 shows that the error ellipse is expanded due to the repeater delay, Figure 8 is an error ellipse excluding the repeater delay effect according to the present embodiment Figure is shown.

The covariance of the calculated position is

이 값은 측정값이 시간별로 서로 독립적인 관계를 가지고 있으므로 측정값의 분산들로 이루어진 대각행렬 형태를 가지고 있다.

This value is in the form of a diagonal matrix consisting of the variances of the measurements since the measurements are independent of each other over time.

값은 시스템에서 주어지는 측정값의 표준 편차이다.*

The value is the standard deviation of the measurements given by the system.

In the matrix above, the diagonal component is the position (x, y) variance of the mobile phone.

Therefore, the root square value of the diagonal component becomes the standard deviation value of the mobile telephone position.

The two-dimensional error ellipse is expressed as the position (x, y) or (east, north) of the terminal with the covariance information of the positions thus obtained.

Since the ellipsoid of FIG. 9 has an inclination by tan θ, x and y are projected on the new coordinate axis (Z axis) by θ.

therefore,

The relationship with the new coordinate axis is obtained by converting covariance information into eigenvalues.

->

->

->

eigenvalues can be obtained as

->

x and y are points on a curve expressed in quadratic form, where the quadratic curve is an ellipse.

Ellipses can be represented in quadratic form as follows:

->

In this case, C, which determines the size of the error ellipse, is determined by a chi distribution having a 95% probability of two degrees of freedom.

이므로 C값은 아래의 테이블에 의하여 결정된다.In other words,

Therefore, the C value is determined by the table below.

c

c 0.3935 (Standard ellipse) One 0.90 2.146 0.8647 (2 ellipse) 2 0.95 (Confidence level) 2.448 0.9889 3 0.99 3.035

The long and short radius of the error ellipse is obtained as follows.

--- Long radius of error ellipse:

--- Short radius of error ellipse:

Using the above equation, select the repeater so that the long and short radius of the error ellipse has the smallest value by calculating the long and short radius of the error ellipse instead of the coordinate of the repeater instead of the base station coordinates, and then correct the coordinates and time delay of the repeater The final position of the terminal can be obtained by using.

In the above, it is preferable that the signal received at the terminal is four or more. If it is less than 4, the number of cases where the repeater cannot be identified by the calculation, or the calculation is impossible due to the lack of a formula for calculating the two-dimensional plane, or the number of cases between the combination of repeaters in the multi-relay situation It is because it can make calculation difficult.

In the above, the database of the repeater includes the repeater number of each repeater, the repeater coordinate value, the delay time value of the repeater itself, the receiving main base station number and the distance from the base station to the repeater, the base station number of the second century being received, and from the base station. It is preferable to include information such as the distance to the repeater.

The above embodiments are only preferred embodiments of the present invention, and the embodiments are understood by those skilled in the art to which the present invention may be variously modified or adjusted. Such modifications and adjustments may be made to the following claims. If the invention described in this and equivalent invention, it belongs to the scope of the present invention.

As described above, the present invention overcomes the position error caused by the delay delay in estimating the position of the terminal, and estimates the position of the terminal more accurately by enabling the position estimation of the terminal without the repeater effect using the repeater information. can do.

Claims (3)

delete A first step of estimating a virtual position of the terminal using a coordinate value of each signal source and a time difference of arrival of each signal by considering each base station as a signal source after the terminal receives a signal transmitted from a base station or a repeater; Determining whether the received signal passes through a repeater, and selecting the repeater when the received signal passes through the repeater;  Considering the selected repeater as a signal source, compensating a delay effect of the selected repeater, and estimating the position of the terminal by using a coordinate value of each signal source and a time difference of arrival of each signal; A method of estimating a terminal position in a mobile communication system for estimating the position of a terminal using base station information and repeater information, The second step is the calculated R value which is the average of the distance between the virtual position of the terminal and the coordinate value of each signal source, the distance between the virtual position of the terminal and the coordinate value of each signal source and the time difference of arrival of each signal After calculating the W value which is the average of the difference between the measurement distances between the terminal and each signal source, if the W value is equal to or greater than the R value, it is determined that the signal is passed through the repeater. Calculating a R value and a W value by estimating the position of the terminal, and selecting a repeater having a W value less than the R value as a repeater via a received signal. Location estimation method. The method of claim 2, wherein in the second step, after setting an error limit of a position error generated by a repeater delay effect, the virtual position of the terminal is compared with the error limit to determine whether the signal passes through a repeater, and the repeater In the mobile communication system, if it is determined that the signal is passed through, each repeater is regarded as a signal source, and an error ellipse is obtained, and the repeater generating the least error ellipse is selected as a repeater through the received signal. Terminal location estimation method.

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