MOBILE STATION

• US 20110009068A1
• Filed: 07/07/2010
• Published: 01/13/2011
• Est. Priority Date: 07/08/2009
• Status: Active Grant

• Current Assignee: Kyocera Corporation
• Original Assignee: Kyocera Corporation
• Inventors: MIURA, Takanori
• Granted Patent: US 8,340,684 B2
• Time in Patent Office: Days
• US Class Current: 455/67.11
• CPC Class Codes: H04B 17/27 for locating or positioning the transmitter
• CPC Class Codes: H04B 17/318 Received signal strength

Abstract

A method of estimating a location of a mobile station is disclosed. A received signal strength of a signal transmitted from a base station is measured. Based on the received signal strength, determination is made whether a signal propagation path to the base station is non-line-of-sight. If the signal propagation path is non-line-of-sight, a distance to the base station is estimated based on a propagation model of the base station.

Claims

1. A mobile station comprising:

a signal-measuring module operable to measure a received signal strength of at least one signal from at least one base station to obtain a measured received signal strength;

a determining module operable to determine, based on the measured received signal strength, whether a propagation path to the at least one base station is non-line-of-sight; and

a distance-estimating module operable to estimate a distance to the at least one base station based on a propagation model of the at least one base station, if the propagation path is non-line-of-sight.

2. The mobile station according to claim 1, further comprising a reception level-estimating module operable to estimate an ideal signal level of a signal sent to the at least one base station.

3. The mobile station according to claim 2, wherein the determining module is further operable to determine that the propagation path is non-line-of-sight, if a difference between the measured received signal strength and the ideal signal level exceeds a predetermined value.

4. The mobile station according to claim 2, wherein the reception level-estimating module is further operable to estimate the ideal signal level based on a transmission power of the at least one base station.

5. The mobile station according to claim 2, wherein the received signal strength is measured substantially simultaneously with estimating the ideal signal level.

6. The mobile station according to claim 1, further comprising a control module operable to estimate a location of the mobile station based on the distance.

7. The mobile station according to claim 6, wherein:

the distance-estimating module is further operable to estimate respective distances to each of a plurality of base stations; and

the control module is further operable to calculate;

a plurality of circles having respective locations of each of the base stations as respective centers thereof and having each of the respective distances as a radius of each of the circles respectively; and

a location of the mobile station in an overlapping region where the circles overlap.

8. The mobile station according to claim 1, further comprising a storage module operable to store the propagation model.

9. The mobile station according to claim 1, wherein the propagation model comprises reception levels of at least one of the group consisting of:

reflected waves, diffracted waves, and reduced waves.

10. A method of estimating a location of a mobile station that communicates with base stations, the method comprising:

measuring a first received signal strength of a signal transmitted from a first base station to obtain a measured first received signal strength;

determining whether a first propagation path to the first base station is non-line-of-sight based on the measured first received signal strength; and

estimating a first distance to the first base station based on a first propagation model of the first base station, if the first propagation path is non-line-of-sight.

11. The method of estimating a location of a mobile station according to claim 10, further comprising receiving data comprising propagation models of one or more base stations from the first base station.

12. The method of estimating a location of a mobile station according to claim 10, further comprising estimating the first distance based on a combination of propagation models of the base stations, wherein each of the base stations is searched for and found by the mobile station.

13. The method of estimating a location of a mobile station according to claim 10, further comprising:

measuring a second received signal strength of a signal transmitted from a second base station to obtain a measured second received signal strength;

determining whether a second propagation path to the second base station is non-line-of-sight based on the measured second received signal strength;

estimating a second distance to the second base station based on a second propagation model of the second base station, if the second propagation path is non-line-of-sight; and

estimating the location of the mobile station based on the first distance and the second distance.

14. The method of estimating a location of a mobile station according to claim 13, wherein the second propagation model comprises reception levels of at least one of the group consisting of:

reflected waves, diffracted waves, and reduced waves.

15. The method of estimating a location of a mobile station according to claim 10, wherein the first propagation model comprises reception levels of at least one of the group consisting of:

reflected waves, diffracted waves, and reduced waves.

16. The method of estimating a location of a mobile station according to claim 10, further comprising:

estimating respective distances to each of a plurality of base stations;

calculating a plurality of circles having respective locations of each of the base stations as respective centers thereof and having each of the respective distances as a radius of each of the circles respectively; and

locating the mobile station in an overlapping region where the circles overlap.

18. The computer readable medium according to claim 16, further comprising program code for receiving data comprising propagation models of one or more base stations from the first base station.

19. The computer readable medium according to claim 16, further comprising program code for estimating the first distance to the first base station based on propagation models of a plurality of base stations, wherein each of the base stations is searched for and found by the mobile station.

20. The computer readable medium according to claim 16, further comprising program code for:

measuring a second received signal strength transmitted from a second base station to obtain a measured second received signal strength;

determining whether a second propagation path to the second base station is non-line-of-sight based on the measured second received signal strength;

estimating a second distance to the second base station based on the second propagation model related to the second base station, if the second propagation path is non-line-of-sight; and

estimating the location of the mobile station based on the first distance and the second distance.

17. A computer readable medium comprising program code for estimating a location of a mobile station, the program code for:

measuring a received signal strength of a signal transmitted from a first base station to obtain a measured first received signal strength;

determining whether a first propagation path to the first base station is non-line-of-sight based on the measured first received signal strength; and

estimating a first distance to the first base station based on the propagation model of the first base station, if the first propagation path is non-line-of-sight.