Mobile user position locating system

• US 7,177,653 B2
• Filed: 09/17/2004
• Issued: 02/13/2007
• Est. Priority Date: 09/19/2003
• Status: Expired due to Fees

• Current Assignee: Bell Mobility Incorporated (BCE Incorporated)
• Original Assignee: Bell Mobility Incorporated (BCE Incorporated)
• Inventors: McAvoy, Derek
• Primary Examiner(s): Feild; Joseph
• Assistant Examiner(s): NGUYEN, KHAI MINH
• Application Number:
  US10/942,862
• Publication Number:
  US 20050064879A1
• Time in Patent Office: 879 Days
• Field of Search: 455/456.1, 455/456.2, 455/456.5, 455/456.6, 455/466, 455/7, 455/11.1, 455/13.1, 455/446, 455/436, 455/439, 455/442, 455/445, 342/450, 342/457
• US Class Current: 455/456.1
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A method and system for locating a mobile user of one or more mobile users while on a call in a wireless telecommunication network utilizes a decision network that determines if the call signal is propagating through a repeater station. When the call is propagating through a repeater station, the decision network alters the signal measurement parameters to correspond with the location of the mobile user relative to the repeater station co-ordinates. By revising signal measurement parameters to compensate for repeater stations, the present invention provides for improved position estimates of the location of the mobile user in the network. For multiple cell soft handoff conditions, the decision network utilizes trained neural networks.

Claims

1. A method of locating a mobile user in a wireless communication network comprising:

receiving a log of call history information records of the mobile user while on a call, the call history information records each comprising at least one distance related measurement parameter;

determining if the call is being routed through a repeater for each of the call history information records;

determining a position estimate of the mobile user, when the call is not routed through a repeater, based on base station cell site co-ordinates and the at least one distance related measurement; and

,

determining a repeater modified position estimate, when the call is routed through a repeater, by modifying the at least one distance related measurement parameter to reflect signal propagation delays associated with the repeater and utilizing the modified distance related measurement parameter with the repeater co-ordinates to determine the repeater modified position estimate.

2. The method of claim 1, wherein the at least one distance related measurement parameter is selected from the group comprising round trip delay (RTD) measurements, power strength measurement messages (PSMM), base station cell site co-ordinates, repeater co-ordinates, cell antenna azimuth, and repeater antenna azimuth, and wherein:

the determining a position estimate of the mobile user comprises utilizing base station cell site co-ordinates and an appropriate one of the RTD and PSMM measurements; and

the determining a repeater modified position estimate comprises modifying the appropriate one of the RTD and PSMM measurements to reflect signal propagation delays associated with the repeater and utilizing the modified RTD and PSMM measurements with the repeater co-ordinates to determine the modified repeater position estimate.

3. The method of claim 2, wherein the determining if the call is being routed through a repeater for a record involving a single base station cell site further comprises:

determining if the RTD measurements in one direction are less than one way delay through the repeater and transmission time from the base station cell site to the repeater, and

ignoring the RTD measurement when it is greater than one way delay through the repeater and transmission time from the base station cell site to the repeater.

4. The method of claim 3, wherein the determining a position estimate comprises triangulation using the RTD measurement and the cell antenna azimuth of the single cell site.

5. The method of claim 2, wherein the determining if a call is being routed through the repeater further comprises:

training an RTD neural network for each location between at least two cell sites with a plurality of predetermined normal and repeater enhanced RTD measurements to develop normal RTD measurement patterns and repeater enhanced RTD patterns,

comparing the RTD measurement of a call history record in the RTD neural network with normal and repeater enhanced RTD patterns to determine if the RTD measurement is being routed through the repeater,

training a PSMM neural network for each location between at least three cell sites with normal and repeater enhanced PSMM measurements to develop normal PSMM measurement patterns and repeater enhanced PSMM patterns, and

comparing the PSMM measurement of a call history record in the PSMM neural network with normal and repeater enhanced PSMM patterns to determine if the PSMM measurement is being routed through the repeater.

6. The method of claim 5, wherein the determining a position estimate and determining a repeater modified position estimate comprise:

a) where the call history record comprises a plurality of RTD measurements from a corresponding plurality of cell sites, utilizing circular trilateration using appropriate RTD and modified RTD measurements; and

,

b) where the call history record comprises PSMM messages from more than three corresponding cell sites, utilizing hyperbolic trilateration using the appropriate PSMM and PSMM modified measurements.

7. The method of claim 2, wherein the determining a position estimate and determining a repeater modified position estimate comprise:

a) where the call history record comprises a plurality of RTD measurements from a corresponding plurality of cell sites, utilizing circular trilateration using appropriate RTD and modified RTD measurements; and

,

b) where the call history record comprises PSMM messages from at least three corresponding cell sites, utilizing hyperbolic trilateration using the appropriate PSMM and PSMM modified measurements.

8. The method of claim 1 further comprising filtering the position estimate and repeater position estimate through a first filter to refine the position estimate and the repeater position estimate.

9. The method of claim 8 further comprising:

determining the end of the call history information and reverse filtering to thereby further refine all the refined position and repeater position estimates.

10. The method of claim 9, wherein the reverse filtering comprises a reverse Kalman filtering by comparing previous position estimates with succeeding position estimates.

11. The method of claim 8, wherein the filtering comprises a Kalman filtering by comparing a current position estimate with previous position estimates.

12. A system for locating a mobile user in a wireless communication network, the system comprising:

a decision network for determining if the call is being routed through a repeater for each of the call history information records; and

,

a position estimating processor responsive to the decision network for determining a position estimate of the mobile user, when the call is not routed through a repeater, based on the base station cell site co-ordinates and at least one distance related measurement parameter, and for determining a repeater modified position estimate, when the call is routed through a repeater, by modifying the at least one distance related measurement parameter to reflect signal propagation delays associated with the repeater and utilizing the modified distance related measurements with the repeater co-ordinates to determine the modified repeater position estimate.

13. The system of claim 12, wherein the system is responsive to logs of call history information records of the mobile user while on a call comprising at least one of the distance related measurement parameter selected from the group comprising round trip delay (RTD) measurements, power strength measurement messages (PSMM), base station cell site co-ordinates, repeater co-ordinates, cell antenna azimuth, and repeater antenna azimuth;

and

wherein the position estimating processor for determining a position estimate of the mobile user, when the call is not routed through a repeater, based on base station cell site co-ordinates and an appropriate one of the RTD and PSMM measurements and for determining a repeater modified position estimate, when the call is routed through a repeater, by modifying the appropriate one of the RTD and PSMM measurements to reflect signal propagation delays associated with the repeater and utilizing the modified RTD and PSMM measurements with the repeater co-ordinates to determine the repeater modified position estimate.

14. The system of claim 13, wherein the position estimate processor determines the position estimate and the repeater modified position:

a) where the call history record comprises a plurality of RTD measurements from a corresponding plurality of cell sites, utilizing a circular trilateration algorithm using appropriate RTD and modified RTD measurements; and

,

b) where the call history record comprises PSMM messages from more than three corresponding cell sites, utilizing a hyperbolic trilateration algorithm using the appropriate PSMM and PSMM modified measurements.

15. The system of claim 12 further comprising a first filter for receiving the position estimate and repeater position estimate from the position estimating processor and for refining the position estimate and the repeater position estimate.

16. The system of claim 15 further comprising a second reverse filter for reverse filtering the position refined position estimates and repeater position estimates to further refine all the refined position and repeater position estimates.

17. The system of claim 16, wherein the second reverse filter comprises a reverse Kalman filter.

18. The system of claim 15, wherein the first filter comprises a Kalman filter.

19. The system of claim 12, wherein the decision network comprises a single cell processor for determining if the RTD measurements in one direction are less than one way delay through the repeater and transmission time from the base station cell site to the repeater, and for discarding the RTD measurement when it is greater than one way delay through the repeater and transmission time from the base station cell site to the repeater.

20. The system of claim 19, wherein the position estimating processor utilizes a triangulation algorithm using the RTD measurement and the cell antenna azimuth of the single cell site.

21. The system of claim 19, wherein the decision network comprises an RTD neural network and a PSMM neural network,

a) the RTD neural network being trained for each location between at least two cell sites with a plurality of predetermined normal and repeater enhanced RTD measurements to develop normal RTD measurement patterns and repeater enhanced RTD measurement patterns, and the RTD neural network comprising a comparator for comparing the RTD measurement of a call history record with normal and repeater enhanced RTD measurement patterns to determine if the RTD measurement is being routed through the repeater, and,

b) the PSMM neural network being trained for each location between at least three cell sites with normal and repeater enhanced PSMM measurements to develop normal PSMM measurement patterns and repeater enhanced PSMM patterns, and the PSMM neural network comprising a comparator for comparing the PSMM measurement of a call history record in the PSMM neural network with normal and repeater enhanced PSMM patterns to determine if the PSMM measurement is being routed through the repeater.

22. The system of claim 21, wherein the position estimate processor determines the position estimate and the repeater modified position:

a) where the call history record comprises a plurality of RTD measurements from a corresponding plurality of cell sites, utilizing a circular trilateration algorithm using appropriate RTD and modified RTD measurements; and

,

b) where the call history record comprises PSMM messages from more than three corresponding cell sites, utilizing a hyperbolic trilateration algorithm using the appropriate PSMM and PSMM modified measurements.

23. An apparatus for locating a mobile user in a wireless communication network comprising:

means for receiving a log of call history information records of the mobile user while on a call, the call history information records each comprising at least one distance related measurement parameter;

means for determining if the call is being routed through a repeater for each of the call history information records;

means for determining a position estimate of the mobile user, when the call is not routed through a repeater, based on base station cell site co-ordinates and the at least one distance related measurement; and

,

means for determining a repeater modified position estimate, when the call is routed through a repeater, by modifying the at least one distance related measurement parameter to reflect signal propagation delays associated with the repeater and utilizing the modified distance related measurement parameter with the repeater co-ordinates to determine the repeater modified position estimate.

24. The apparatus of claim 23, wherein the at least one distance related measurement parameter is selected from the group comprising round trip delay (RTD) measurements, power strength measurement messages (PSMM), base station cell site co-ordinates, repeater co-ordinates, cell antenna azimuth, and repeater antenna azimuth, and wherein:

the means for determining a position estimate of the mobile user involves utilizing base station cell site co-ordinates and an appropriate one of the RTD and PSMM measurements; and

the means for determining a repeater modified position estimate involves modifying the appropriate one of the RTD and PSMM measurements to reflect signal propagation delays associated with the repeater and utilizing the modified RTD and PSMM measurements with the repeater co-ordinates to determine the repeater modified position estimate.

25. The apparatus of claim 24, wherein the means for determining if the call is being routed through a repeater for a record involves a single base station cell site further comprises:

means for determining if the RTD measurements in one direction are less than one way delay through the repeater and transmission time from the base station cell site to the repeater, and

means for ignoring the RTD measurement when it is greater than one way delay through the repeater and transmission time from the base station cell site to the repeater.

26. The apparatus of claim 25, wherein the means for determining a position estimate comprises triangulation using the RTD measurement and the cell antenna azimuth of the single cell site.

27. The apparatus of claim 24, wherein the means for determining if a call is being routed through the repeater further comprises:

means for training an RTD neural network for each location between at least two cell sites with a plurality of predetermined normal and repeater enhanced RTD measurements to develop normal RTD measurement patterns and repeater enhanced RTD patterns,

means for comparing the RTD measurement of a call history record in the RTD neural network with normal and repeater enhanced RTD patterns to determine if the RTD measurement is being routed through the repeater,

means for training a PSMM neural network for each location between at least three cell sites with normal and repeater enhanced PSMM measurements to develop normal PSMM measurement patterns and repeater enhanced PSMM patterns, and

means for comparing the PSMM measurement of a call history record in the PSMM neural network with normal and repeater enhanced PSMM patterns to determine if the PSMM measurement is being routed through the repeater.

28. The apparatus of claim 27, wherein the means for determining a position estimate and of determining a repeater modified position estimate comprise:

a) where the call history record comprises a plurality of RTD measurements from a corresponding plurality of cell sites, means utilizing circular trilateration using appropriate RTD and modified RTD measurements; and

,

b) where the call history record comprises PSMM messages from more than three corresponding cell sites, means utilizing hyperbolic trilateration using the appropriate PSMM and PSMM modified measurements.

29. The apparatus of claim 24, wherein the means for determining a position estimate and of determining a repeater modified position estimate comprise:

a) where the call history record comprises a plurality of RTD measurements from a corresponding plurality of cell sites, means utilizing circular trilateration using appropriate RTD and modified RTD measurements; and

,

b) where the call history record comprises PSMM messages from at least three corresponding cell sites, means utilizing hyperbolic trilateration using the appropriate PSMM and PSMM modified measurements.

30. The apparatus of claim 23 further comprising means for filtering the position estimate and repeater position estimate to refine the position estimate and the repeater position estimate.

31. The apparatus of claim 30, wherein the filtering means comprises a Kalman filter for comparing a current position estimate with previous position estimates.

32. The apparatus of claim 31, wherein the reverse filtering means comprises a reverse Kalman filter for comparing previous position estimates with succeeding position estimates.

33. The apparatus of claim 23 further comprising:

means for determining the end of the call history information and reverse filtering to thereby further refine all the refined position and repeater position estimates.