Methods and apparatus for mobile station location estimation

• US 20040152471A1
• Filed: 03/08/2004
• Published: 08/05/2004
• Est. Priority Date: 04/03/2001
• Status: Active Grant

• Current Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Original Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Inventors: Snapp, John Lawrence, MacDonald, Alan Denis, Sather, Marc W.
• Granted Patent: US 7,519,372 B2
• Time in Patent Office: Days
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/0252 Radio frequency fingerprinting
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04W 4/026 using orientation information, e.g. compass
• CPC Class Codes: H04W 4/90 Services for handling of emergency or hazardous situations, e.g. earthquake and tsunami warning systems [ETWS]
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 64/003 locating network equipment
• CPC Class Codes: H04W 88/14 Backbone network devices

Abstract

Methods and apparatus for estimating mobile station location include receiving reported signal strengths or other attachment indicator values from a mobile station. The reported signal strengths are compared with characteristic received signal strength values in a coverage area of a mobile network. A mobile switching center determines if a location function is requested and initiates a location estimation process by a mobile location module (MLM). The MLM receives the reported signal strength contours associated with the attachment points. Based on a comparison of the reported attachment indicator values with characteristic values, the MLM provides a mobile location estimate.

Claims

1. A mobile station location processor, comprising;

an input configured to receive attachment indicators associated with at least two points of attachment of the mobile station;

a memory configured to store sets of predetermined attachment indicators associated with the at least two points of attachment; and

an estimation unit configured to provide an estimate of the mobile station location based on a comparison of the received attachment indicators and at least one set of the at least two predetermined attachment indicators.

2. The mobile station location processor of claim 1, wherein the estimation unit is configured to provide the estimate of the mobile station location based on a comparison of the received attachment indicator values and the sets of attachment indicator values associated with the at least two points of attachment.

3. The mobile station location processor of claim 2, wherein the received attachment indicator values are reported by the mobile station.

4. The mobile station location processor of claim 3, wherein the attachment indicator values are received signal strength values.

5. The mobile station location processor of claim 1, wherein the attachment indicator values are received signal strength values reported by the mobile station.

6. A mobile location module, comprising:

a processor configured to compare at least two reported received signal strength values with received signal strength values associated with at least two geographical locations in a wireless network; and

an output configured to deliver a mobile location estimate based on the comparison.

7. The mobile location module of claim 6, wherein the processor is configured to determine a score associated with the comparison of the reported received signal strength values with the predetermined received signal strengths.

8. The mobile location module of claim 6, wherein the reported and received signal strength values related to mobile-assisted handoff.

9. A location unit for estimating a location of a mobile station, comprising:

an input configured to receive attachment indicator values associated with the mobile station; and

a processor configured to provide a mobile station location estimate based on predetermined attachment indicator contours associated with network attachment points.

10. The location unit of claim 9, wherein the attachment indicator values are received signal strength values reported by the mobile station and the attachment indicator contours are received signal strength contours.

11. A method of locating a mobile station, comprising:

obtaining a set of received signal strengths associated with the mobile station;

determining a mobile station location based on a comparison of the received signal strengths with predetermined signal strengths.

12. The method of claim 11, further comprising:

determining an error score based on the received signal strengths and the predetermined signal strengths;

wherein the mobile station location is determined by selecting a location associated with selected error score.

13. The method of claim 11, further comprising storing the predetermined signal strengths.

14. A method of locating a mobile station within a geographic service area, comprising:

obtaining attachment indicator values associated with a series of attachment points for the mobile station and; and

comparing the mobile station attachment indicator values with predetermined attachment indicator values associated with the series of attachment points to obtain a mobile station location estimate.

15. The method of claim 14, further comprising reporting the estimated mobile station location estimate.

16. The method of claim 14, wherein the attachment indicator values for the mobile station are reported by the mobile station.

17. The method of claim 16, wherein the attachment indicator values are received signal strength values associated with corresponding radio base stations.

18. The method of claim 14, wherein the attachment indicator values are received signal strength values associated with corresponding radio base stations.

19. The method of claim 14, wherein the mobile station attachment indicator values and the predetermined attachment indicator values are compared by determining a score associated with the predetermined attachment indicator values, and the estimated mobile station location is selected based on the associated score.

20. A method of locating a mobile station, comprising:

obtaining at least one of a latitude and a longitude location estimate based on a global positioning system; and

providing an estimate of mobile station location based on a comparison of mobile station attachment indicator values with predetermined attachment indicator values in a region associated with the latitude and longitude estimates.

21. A method of estimating a mobile station location, comprising:

receiving signal strength values associated with signals received by a mobile station from a plurality of antennas;

calculating a first location area of the mobile station as a geographic coverage area of a serving cell site; and

calculating a second location area of the mobile station based on a comparison of the received signal strength values with predetermined signal strength values associated with at least one location in the coverage area.

22. The method of claim 21, further comprising calculating the characteristic attachment indicator values based on at least one propagation characteristic.

23. The method of claim 22, wherein the at least one propagation characteristic is selected from a group consisting of transmitted power, propagation path slope, and antenna pattern roll-off.

24. A network configured to provide location estimates for a mobile station, comprising:

a processor configured to produce the location estimates based on characteristic attachment indicator values of the network and reported attachment indicator values associated with the mobile station; and

an output configured to deliver the location estimates.

25. The network of claim 24, further comprising a database that includes the characteristic attachment indicator values.

26. The network of claim 24, wherein the processor is configured to determine characteristic attachment indicator values based on at least one propagation characteristic.

27. A method of requesting services from a public-safety answering point (PSAP) with a mobile station, comprising:

delivering a message from the mobile station to the PSAP; and

providing the PSAP an estimate of mobile station location based on a comparison of mobile station attachment indicator values and characteristic attachment indicator values.

28. A method of providing a location estimate for a non-subscribing mobile station in a network, comprising:

receiving a series of attachment indicator values from the mobile station; and

estimating a mobile station location based on characteristic attachment indicator values associated with the network.

29. A method of determining characteristic attachment indicator values for at least a portion of a wireless network, comprising:

measuring the characteristic attachment indicator values; and

storing the characteristic attachment indicator values in a database.

30. The method of claim 29, further comprising associating at least one global positioning system coordinate with the measured characteristic attachment indicator values.

31. A method or revising a database of network characteristic attachment indicator values, comprising:

estimating a location of a mobile station based on a comparison of attachment indicator values reported by the mobile station with the characteristic attachment indicator values;

obtaining an associated global positioning system (GPS) location estimate from the mobile station; and

revising at least one characteristic attachment indicator value based on a comparison of the mobile station location estimate and the GPS location estimate.