Method and system for estimating a subscriber's location in a wireless communication system service area

• US 6,161,018 A
• Filed: 02/27/1998
• Issued: 12/12/2000
• Est. Priority Date: 02/27/1998
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Wang, Shu-Shaw (Peter), Reed, John Douglas
• Primary Examiner(s): Tsang, Fan
• Assistant Examiner(s): Ferguson, Keith
• Application Number:
  US09/032,007
• Time in Patent Office: 1,019 Days
• Field of Search: 455/11.1, 455/67.6, 455/404, 455/422, 455/427, 455/456, 455/457, 455/521, 342/357, 342/453, 342/457, 342/450, 342/451, 342/458, 342/463, 342/464, 701/300
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/02526 using non-dedicated equipment, e.g. user equipment or crowd-sourcing
• CPC Class Codes: G01S 5/02528 Simulating radio frequency fingerprints
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

At a receiver location in a wireless communication system service area, a set of characteristics that describe a received ray of a subscriber signal is measured. In a model of the wireless communication system service area, a propagation path of a model ray launched from a location in the model of the wireless communication system service area that corresponds to the receiver location in the wireless communication system service area is determined, wherein the ray has model signal characteristics based upon the set of characteristics that describe the received ray of the subscriber signal. Thereafter, a subscriber location in the wireless communication system service area is estimated in response to the propagation path of the model ray.

Claims

1. A method for estimating a subscriber location of a subscriber unit in a wireless communication system service area comprising the steps of:

at a receiver location in the wireless communication system service area, measuring a set of characteristics that describe a received ray of a subscriber signal;

in a computer model of the wireless communication system service area, determining a propagation path of a model ray launched from a location in the model of the wireless communication system service area that corresponds to the receiver location in the wireless communication system service area, wherein the model ray has model signal characteristics based upon the set of characteristics that describe the received ray of the subscriber signal, and wherein the model includes an object that can change the propagation path of the model ray; and

estimating a subscriber location in the wireless communication system service area in response to the propagation path of the model ray.

2. The method for estimating a subscriber location according to claim 1 wherein the set of characteristics that describe the received ray of the subscriber signal include a time of flight, an angle of arrival, and a signal amplitude.

3. The method for estimating a subscriber location according to claim 1 wherein an angle of arrival measurement includes an angle of uncertainty, and further including the steps of:

in the model of the wireless communication system service area, determining M propagation paths of M model rays launched from the location in the model of the wireless communication system service area that corresponds to the receiver location, wherein M is an integer greater than 1, and wherein each of the M model rays are launched at an angle within the angle of uncertainty of the angle of arrival measurement;

estimating a first set of M estimated subscriber locations in the wireless communication system service area in response to the M propagation paths of the M model rays; and

estimating a subscriber location in the wireless communication system service area in response to the first set of M estimated subscriber locations.

4. The method for estimating a subscriber location according to claim 3 further including the steps of:

at a second receiver location in the wireless communication system service area, measuring a second set of characteristics that describe a second received ray of the subscriber signal;

in the model of the wireless communication system service area, determining N propagation paths of N model rays launched from a second location in the model of the wireless communication system service area that corresponds to the second receiver location in the wireless communication system service area, wherein N is an integer greater than 1, and wherein each of the N model rays are launched at an angle within a second angle of uncertainty of a second angle of arrival measurement;

estimating a second set of N estimated subscriber locations in the wireless communication system service area in response to the N propagation paths of the N model rays; and

selecting a final estimated subscriber location based on the first set of M estimated subscriber locations and the second set of N estimated subscriber locations.

5. The method for estimating a subscriber location according to claim 4 wherein the second receiver location is the same as the receiver location.

6. The method for estimating a subscriber location according to claim 4 wherein the step of selecting a final estimated subscriber location based on the estimated subscriber locations further includes the steps of:

determining a degree of clustering of clusters of estimated subscriber locations, wherein each cluster includes an estimated subscriber location in both the first and second sets of estimated subscriber locations; and

selecting a final estimated subscriber location based upon the degree of clustering of the clusters of estimated subscriber locations.

7. The method for estimating a subscriber location according to claim 6 wherein the step of determining a degree of clustering further includes determining a degree of clustering based upon distances between a selected point and selected estimated subscriber locations in the cluster of estimated subscriber locations.

8. The method for estimating a subscriber location according to claim 1 wherein the step of determining a propagation path of a model ray further includes determining a propagation path of a model ray using ray-tracing techniques.

9. The method for estimating a subscriber location according to claim 1 wherein the propagation path of the model ray has a terminal point, and wherein the step of estimating a subscriber location further includes estimating that the subscriber location is the terminal point of the propagation path of the model ray.

10. The method for estimating a subscriber location according to claim 1 further including the step of:

verifying the estimated subscriber location by;

launching, in the model, a verification ray from the estimated subscriber location;

estimating characteristics of the verification ray at the location in the model of the wireless communication system service area that corresponds to the receiver location in the wireless communication system service area;

comparing the estimated characteristics of the verification ray with the measured set of characteristics that describe the received ray of the subscriber signal; and

determining a quality of the estimated subscriber location based upon the comparison of the estimated characteristics of the verification ray and the measured set of characteristics that describe the received ray of the subscriber signal.

11. The method for estimating a subscriber location according to claim 10 wherein the step of determining a quality of the estimated subscriber location further includes decreasing a quality of the estimated subscriber location in response to the measured set of characteristics that describe the received ray of the subscriber signal differing, by a predetermined threshold, from the estimated characteristics of the verification ray.

12. The method for estimating a subscriber location according to claim 1 further including the steps of:

measuring a set of signal characteristics that describe a received ray of a subscriber signal transmitted from a known location in the wireless communication system service area; and

adjusting factors used in determining the estimated subscriber location in response to comparing a correlation between the estimated subscriber location and the known location.

13. A system for estimating a subscriber location of a subscriber unit in a wireless communication system service area comprising:

means for measuring a set of characteristics that describe a received ray of a subscriber signal at a receiver location in the wireless communication system service area;

means for determining a propagation path of a model ray in a model of the wireless communication system service area launched from a location in the model of the wireless communication system service area that corresponds to the receiver location in the wireless communication system service area, wherein the model ray has model signal characteristics based upon the set of characteristics that describe the received ray of the subscriber signal, and wherein the model includes an object that can change the propagation path of the model ray; and

means for estimating a subscriber location in the wireless communication system service area in response to the propagation path of the model ray.

14. The system for estimating a subscriber location according to claim 13 wherein the set of characteristics that describe the received ray of the subscriber signal include a time of flight, an angle of arrival, and a signal amplitude.

15. The system for estimating a subscriber location according to claim 14 wherein an angle of arrival measurement includes an angle of uncertainty, and further including:

means for determining M propagation paths of M model rays in the model of the wireless communication system service area launched from the location in the model of the wireless communication system service area that corresponds to the receiver location, wherein M is an integer greater than 1, and wherein each of the M model rays are launched at an angle within the angle of uncertainty of the angle of arrival measurement;

means for estimating a first set of M estimated subscriber locations in the wireless communication system service area in response to the M propagation paths of the M model rays; and

means for estimating a subscriber location in the wireless communication system service area in response to the first set of M estimated subscriber locations.

16. The system for estimating a subscriber location according to claim 15 further including:

means for measuring a second set of characteristics that describe a second received ray of the subscriber signal at a second receiver location in the wireless communication system service area;

means, in the model of the wireless communication system service area, for determining N propagation paths of N model rays launched from a second location in the model of the wireless communication system service area that corresponds to the second receiver location in the wireless communication system service area, wherein N is an integer greater than 1, and wherein each of the N model rays are launched at an angle within a second angle of uncertainty of a second angle of arrival measurement;

means for estimating a second set of N estimated subscriber locations in the wireless communication system service area in response to the N propagation paths of the N model rays; and

means for selecting a final estimated subscriber location based on the first set of M estimated subscriber locations and the second set of N estimated subscriber locations.

17. The system for estimating a subscriber location according to claim 15 wherein the second receiver location is the same as the receiver location.

18. The system for estimating a subscriber location according to claim 16 wherein the means for selecting a final estimated subscriber location based on the estimated subscriber locations further includes:

means for determining a degree of clustering of clusters of estimated subscriber locations, wherein each cluster includes an estimated subscriber location in both the first and second sets of estimated subscriber locations; and

means for selecting a final estimated subscriber location based upon the degree of clustering of the clusters of estimated subscriber locations.

19. The system for estimating a subscriber location according to claim 18 wherein the means for determining a degree of clustering further includes means for determining a degree of clustering based upon distances between a selected point and selected estimated subscriber locations in the cluster of estimated subscriber locations.

20. The system for estimating a subscriber location according to claim 13 wherein the means for determining a propagation path of a model ray further includes means for determining a propagation path of a model ray using ray-tracing techniques.

21. The system for estimating a subscriber location according to claim 13 wherein the propagation path of the model ray has a terminal point, and wherein the means for estimating a subscriber location further includes means for estimating that the subscriber location is the terminal point of the propagation path of the model ray.

22. The system for estimating a subscriber location according to claim 13 further including:

means for verifying the estimated subscriber location including;

means for launching, in the model, a verification ray from the estimated subscriber location;

means for estimating characteristics of the verification ray at the location in the model of the wireless communication system service area that corresponds to the receiver location in the wireless communication system service area;

means for comparing the estimated characteristics of the verification ray with the measured set of characteristics that describe the received ray of the subscriber signal; and

means for determining a quality of the estimated subscriber location based upon the comparison of the estimated characteristics of the verification ray and the measured set of characteristics that describe the received ray of the subscriber signal.

23. The system for estimating a subscriber location according to claim 22 wherein the means for determining a quality of the estimated subscriber location further includes means for decreasing a quality of the estimated subscriber location in response to the measured set of characteristics that describe the received ray of the subscriber signal differing, by a predetermined threshold, from the estimated characteristics of the verification ray.

24. The system for estimating a subscriber location according to claim 13 further including:

means for measuring a set of signal characteristics that describe a received ray of a subscriber signal transmitted from a known location in the wireless communication system service area; and

means for adjusting factors used in determining the estimated subscriber location in response to comparing a correlation between the estimated subscriber location and the known location.

25. A computer program product comprising:

a computer useable medium having computer readable program code means embodied therein for estimating a location of a subscriber unit in a wireless communication system service area comprising;

computer readable program code means for measuring a set of characteristics that describe a received ray of a subscriber signal at a receiver location in the wireless communication system service area;

computer readable program code means for determining a propagation path of a model ray launched in a model of the wireless communication system service area from a location in the model of the wireless communication system service area that corresponds to the receiver location in the wireless communication system service area, wherein the model ray has model signal characteristics based upon the set of characteristics that describe the received ray of the subscriber signal, and wherein the model includes an object that can change the propagation path of the model ray; and

computer readable program code means for estimating a subscriber location in the wireless communication system service area in response to the propagation path of the model ray.

26. The system for estimating a subscriber location according to claim 25 wherein the set of characteristics that describe the received ray of the subscriber signal include a time of flight, an angle of arrival, and a signal amplitude.

27. The system for estimating a subscriber location according to claim 26 wherein an angle of arrival measurement includes an angle of uncertainty, and further including:

computer readable program code means for determining M propagation paths of M model rays in the model of the wireless communication system service area launched from the location in the model of the wireless communication system service area that corresponds to the receiver location, wherein M is an integer greater than 1, and wherein each of the M model rays are launched at an angle within the angle of uncertainty of the angle of arrival measurement;

computer readable program code means for estimating a first set of M estimated subscriber locations in the wireless communication system service area in response to the M propagation paths of the M model rays; and

computer readable program code means for estimating a subscriber location in the wireless communication system service area in response to the first set of M estimated subscriber locations.

28. The system for estimating a subscriber location according to claim 27 further including:

computer readable program code means for measuring a second set of characteristics that describe a second received ray of the subscriber signal at a second receiver location in the wireless communication system service area;

computer readable program code means for determining N propagation paths of N model rays in the model of the wireless communication system service area launched from a second location in the model of the wireless communication system service area that corresponds to the second receiver location in the wireless communication system service area, wherein N is an integer greater than 1, and wherein each of the N model rays are launched at an angle within a second angle of uncertainty of a second angle of arrival measurement;

computer readable program code means for estimating a second set of N estimated subscriber locations in the wireless communication system service area in response to the N propagation paths of the N model rays; and

computer readable program code means for selecting a final estimated subscriber location based on the first set of M estimated subscriber locations and the second set of N estimated subscriber locations.

29. The system for estimating a subscriber location according to claim 28 wherein the second receiver location is the same as the receiver location.

30. The system for estimating a subscriber location according to claim 28 wherein the computer readable program code means for selecting a final estimated subscriber location based on the estimated subscriber locations further includes:

computer readable program code means for determining a degree of clustering of clusters of estimated subscriber locations, wherein each cluster includes an estimated subscriber location in both the first and second sets of estimated subscriber locations; and

computer readable program code means for selecting a final estimated subscriber location based upon the degree of clustering of the clusters of estimated subscriber locations.

31. The system for estimating a subscriber location according to claim 30 wherein the computer readable program code means for determining a degree of clustering further includes computer readable program code means for determining a degree of clustering based upon distances between a selected point and selected estimated subscriber locations in the cluster of estimated subscriber locations.

32. The system for estimating a subscriber location according to claim 25 wherein the computer readable program code means for determining a propagation path of a model ray further includes computer readable program code means for determining a propagation path of a model ray using ray-tracing techniques.

33. The system for estimating a subscriber location according to claim 25 wherein the propagation path of the model ray has a terminal point, and wherein the computer readable program code means for estimating a subscriber location further includes computer readable program code means for estimating that the subscriber location is the terminal point of the propagation path of the model ray.

34. The system for estimating a subscriber location according to claim 25 further including:

computer readable program code means for verifying the estimated subscriber location including;

computer readable program code means for launching, in the model, a verification ray from the estimated subscriber location;

computer readable program code means for estimating characteristics of the verification ray at the location in the model of the wireless communication system service area that corresponds to the receiver location in the wireless communication system service area;

computer readable program code means for comparing the estimated characteristics of the verification ray with the measured set of characteristics that describe the received ray of the subscriber signal; and

computer readable program code means for determining a quality of the estimated subscriber location based upon the comparison of the estimated characteristics of the verification ray and the measured set of characteristics that describe the received ray of the subscriber signal.

35. The system for estimating a subscriber location according to claim 34 wherein the computer readable program code means for determining a quality of the estimated subscriber location further includes computer readable program code means for decreasing a quality of the estimated subscriber location in response to the measured set of characteristics that describe the received ray of the subscriber signal differing, by a predetermined threshold, from the estimated characteristics of the verification ray.

36. The system for estimating a subscriber location according to claim 25 further including:

computer readable program code means for measuring a set of signal characteristics that describe a received ray of a subscriber signal transmitted from a known location in the wireless communication system service area; and

computer readable program code means for adjusting factors used in determining the estimated subscriber location in response to comparing a correlation between the estimated subscriber location and the known location.