Method and System for Determining Position of Mobile Communication Device Using Ratio Metric

• US 20080261622A1
• Filed: 06/16/2006
• Published: 10/23/2008
• Est. Priority Date: 08/17/2005
• Status: Abandoned Application

• Current Assignee: Radiant Technologies, Inc. (Salesforce.com, Inc.)
• Original Assignee: Radiant Technologies, Inc. (Salesforce.com, Inc.)
• Inventors: Kim, Tae Il, Kwon, Tae Kyoung, Ha, Tae Joon, Lee, Jeong Keun, Lee, Hee Man
• Application Number:
  US11/596,375
• Publication Number:
  US 20080261622A1
• Time in Patent Office: Days
• US Class Current: 455/456.2
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A method of determining a location of a mobile communication terminal, the method including: receiving base station identification signals from a plurality of base stations; calculating distance ratios between the plurality of base stations and the mobile communication terminal, from the received base station identification signals; generating first variables and second variables from the distance ratios; and determining the location of the mobile communication terminal from the first variables and the second variables is provided.

Claims

1. A method of determining a location of a mobile communication terminal, the method comprising:

receiving base station identification signals from a plurality of base stations;

calculating distance ratios between the plurality of base stations and the mobile communication terminal, from the received base station identification signals;

generating first variables and second variables from the distance ratios; and

determining the location of the mobile communication terminal from the first variables and the second variables.

2. The method of claim 1, wherein each of the distance ratios designates a ratio which is acquired by comparing a distance between a particular base station and the mobile communication terminal with the distance between each of the plurality of base stations and the mobile communication terminal.

3. The method of claim 1, wherein the distance ratios are calculated based on a power difference between two base station identification signals which are received from the plurality of base stations.

4. The method of claim 1, wherein the first variables and the second variables correspond to centers and radiuses of an Apollonius circles respectively.

5. The method of claim 4, wherein the location of the mobile communication terminal corresponds to a location where a sum of squares of distances from the centers of the Apollonius circles to the location of the mobile communication terminal becomes a minimal value.

6. The method of claim 4, wherein the location of the mobile communication terminal is determined by,

$X$

( x , y ) = arg 

min X 

Q i = 1 n - 1 

( 

X - O i 

2 - P i 2 ) P i 2

where n designates a number of the base stations, X designates the location of the mobile communication terminal, O designates a center of the Apollonius circle, and P designates a radius of the Apollonius circle.

7. The method of claim 1, further comprising:

determining a center of the plurality of base stations from the received base station identification signals; and

extracting location values of virtual base stations from which a base station identification signal is not received within a predetermined radius from the determined center,

wherein the location values of the virtual base stations are utilized for determining the location of the mobile communication terminal.

8. The method of claim 7, wherein a location of a virtual base station, of which distance with the mobile communication terminal is greater than a threshold value, is reflected in determining the location of the mobile communication terminal, and a location of a virtual base station, of which distance with the mobile communication terminal is less than the threshold value, is not reflected in determining the location of the mobile communication terminal.

9. The method of claim 7, wherein:

the first variables and the second variables correspond to centers and radiuses of an Apollonius circles respectively, and

the location of the mobile communication terminal is determined by,

$X<br><br>\left(x,y\right)=\underset{X}{\arg <br><br><br><br>\min }<br><br>\left\{\begin{array}{c}\stackrel{n-1}{\underset{i=1}{Q}}<br><br>\frac{\left({<br><br>X-O_i<br><br>}^2-P_i^2\right)}{P_i^2}+\\ \stackrel{m}{\underset{j=1}{Q}}<br><br>\frac{\mathrm{SCALE}}{\left(1+\exp <br><br>\left(<br><br>X-V_j<br><br>-D_{\mathrm{th}}\right)\right)}\end{array}\right\}$

where n designates a number of the base stations, m designates a number of the virtual base stations, X designates the location of the mobile communication terminal, O designates a center of the Apollonius circle, P designates a radius of the Apollonius circle, SCALE designates a coefficient, V designates a location of a virtual base station, and D designates a threshold value.

17. A computer-readable recording medium storing a program for implementing the method according to claim 1.

10. A method of determining a location of a mobile communication terminal, the method comprising:

receiving base station identification signals from a plurality of base stations;

calculating weights based on a distance between each of the plurality of base stations and the mobile communication terminal, from the received base station identification signals; and

determining the location of the mobile communication terminal from the weights and location values of the plurality of base stations.

11. The method of claim 10, wherein each of the weights is an inverse of the distance between each of the plurality of base stations and the mobile communication terminal.

12. The method of claim 10, wherein each of the weights designates a ratio which is acquired by comparing a distance between a particular base station and the mobile communication terminal with the distance between each of the plurality of base stations and the mobile communication terminal.

13. The method of claim 10, wherein the mean of location values of the plurality of base stations based on the weights is determined as the location of the mobile communication terminal.

14. A system for determining a location of a mobile communication terminal, the system comprising:

a distance ratio calculation unit calculating distance ratios between a plurality of base stations and the mobile communication terminal, from base station identification signals which are received from the plurality of base stations;

a locus calculation unit generating first variables and second variables from the distance ratios; and

a location determination unit determining the location of the mobile communication terminal from the first variables and the second variables.

15. The system of claim 14, further comprising:

a virtual base station selection unit determining a center of the plurality of base stations from the received base station identification signals, and extracting location values of virtual base stations from which a base station identification signal is not received within a predetermined radius from the determined center,

wherein the location determination unit utilizes the location values of the virtual base stations for determining the location of the mobile communication terminal.

16. A system for determining a location of a mobile communication terminal, the system comprising:

a weight calculation unit calculating weights based on a distance between each of a plurality of base stations and the mobile communication terminal, from base station identification signals which are received from the plurality of base stations; and

a location determination unit determining the location of the mobile communication terminal from the weights and locations values of the plurality of base stations.