Pattern-recognition-based geolocation

• US 6,496,701 B1
• Filed: 08/25/1998
• Issued: 12/17/2002
• Est. Priority Date: 08/25/1998
• Status: Expired due to Term

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Freidenfelds, John, Chen, Byron H., Chiang, Tung C.
• Primary Examiner(s): LEGREE, TRACY MICHELLE
• Application Number:
  US09/139,107
• Time in Patent Office: 1,575 Days
• Field of Search: 455/456, 455/457, 455/504, 455/505, 455/506, 455/67.6, 455/10, 342/378, 342/457, 342/417
• US Class Current: 455/456.5
• CPC Class Codes: G01S 5/02521 using a radio-map
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A technique for identifying a geographical location of a mobile terminal which includes receiving a set of characteristics from the mobile terminal, comparing the set of characteristics from the mobile terminal with a set of attributes for each of the cells, and identifying one of the sub-cells whose attributes most closely match the characteristics from the mobile terminal as the sub-cell in which the mobile terminal located. The attributes may include discrete RF attributes, such as average pilot strength, chip offset, or pilot strength. The attributes may also include continuous features, such as signature waveforms.

Claims

1. A method of identifying a geographical location of a mobile terminal, comprising the steps of:

comparing a set of discrete RF characteristics from the mobile terminal with a set of discrete RF attributes for each of a plurality of sub-cells; and

identifying a sub-cell of the plurality of sub-cells whose set of discrete RF attributes most closely match the set of discrete RF characteristics from the mobile terminal as the sub-cell in which the mobile terminal is located.

2. The method of claim 1, wherein the set of discrete RF attributes for each of the plurality of sub-cells is stored at a mobile system base station or at a mobile switching center.

3. The method of claim 2, wherein only one mobile system base station is required to identify the location of the mobile terminal.

4. The method of claim 1, wherein the comparing and identifying steps are performed using pattern recognition.

5. The method of claim 1, wherein the set of discrete RF attributes for each of the plurality of sub-cells vary based on weather conditions, time of day, and environmental factors.

6. The method of claim 1, wherein said comparing and identifying steps are repeated over time as the mobile terminal moves.

7. The method of claim 1,

said comparing step further comparing the set of discrete RF characteristics from the mobile terminal with the set of discrete RF attributes for each of the plurality of sub-cells and a waveform from the mobile terminal with at least one signature waveform for each of the plurality of sub-cells;

said identifying step identifying the sub-cell of the plurality of sub-cells whose set of discrete RF attributes and at least one signature waveform most closely match the set of discrete RF characteristics and the waveform from the mobile terminal as the sub-cell in which the mobile terminal is located.

8. The method of claim 1, wherein the set of discrete RF characteristics from the mobile terminal include pilot information.

9. The method of claim 8, wherein the pilot information includes at least one of pilot strength information, pilot strength ratio information, observed pilot strength information, average pilot strength information, and chip offset.

10. The method of claim 1, said identifying step utilizing conditional probability to identify the sub-cell of the plurality of sub-cells whose set of RF attributes most closely match the set of RF characteristics from the mobile terminal.

11. The method of claim 10, wherein the conditional probability includes Bayes Theorem.

12. A processor for identifying a geographical location of a mobile terminal, comprising:

a comparing unit for comparing a set of RF discrete characteristics from the mobile terminal with a set of discrete RF attributes for each of a plurality of sub-cells; and

an identifying unit for identifying a sub-cell of the plurality of sub-cells whose set of discrete RF attributes most closely match the set of discrete RF characteristics from the mobile terminal as the sub-cell in which the mobile terminal is located.

13. The processor of claim 12, wherein the set of discrete RF attributes for each of the plurality of sub-cells is stored at a mobile system base station or at a mobile switching center.

14. The processor of claim 13, wherein only one mobile system base station is required to identify the location of the mobile terminal.

15. The processor of claim 12, wherein the comparing and identifying units utilize pattern recognition.

16. The processor of claim 12, wherein the set of discrete RF attributes for each of the plurality of sub-cells vary based on weather conditions, time of day, and environmental factors.

17. The processor of claim 12, wherein said comparing and identifying units repeatedly operate over time as the mobile terminal moves.

18. The processor of claim 12,

said comparing unit further comparing the set of discretion RF characteristics from the mobile terminal with the set of discrete RF attributes for each of the plurality of sub-cells and a waveform from the mobile terminal with at least one. signature waveform for each of the plurality of sub-cells;

said identifying unit identifying the sub-cell of the plurality of sub-cells whose set of discrete RF attributes and at least one signature waveform most closely match the set of discrete RF characteristics and the waveform from the mobile terminal as the sub-cell in which the mobile terminal is located.

19. The processor of claim 12, wherein the set of discrete RF characteristics from the mobile terminal include pilot information.

20. The method of claim 19, wherein the pilot information includes at least one of pilot strength information, pilot strength ratio information, observed pilot strength information, average pilot strength information, and chip offset.

21. The processor of claim 12, said identifying unit utilizing conditional probability to identify the sub-cell of the plurality of sub-cells whose set of RF attributes most closely match the set of RF characteristics from the mobile terminal.

22. The processor of claim 21, wherein the conditional probability includes Bayes Theorem.

23. A computer program embodied in a computer-readable medium for identifying a geographical location of a mobile terminal, comprising:

a comparing source code segment for comparing a set of discrete RF characteristics from the mobile terminal with a set of discrete RF attributes for each of a plurality of sub-cells; and

an identifying source code segment for identifying a sub-cell of the plurality of sub-cells whose set of discrete RF attributes most closely match the set of discrete RF characteristics from the mobile terminal as the sub-cell in which the mobile terminal is located.

24. The computer program of claim 23, wherein the set of discrete RF attributes for each of the plurality of sub-cells is stored at a mobile system base station or at a mobile switching center.

25. The computer program of claim 24, wherein only one mobile system base station is required to identify the location of the mobile terminal.

26. The computer program of claim 23, wherein the comparing and identifying source code segments utilize pattern recognition.

27. The computer program of claim 23, wherein the set of discrete RF attributes for each of the plurality of sub-cells vary based on weather conditions, time of day, and environmental factors.

28. The computer program of claim 23, wherein said comparing and identifying source code segments are executed repeatedly over time as the mobile terminal moves.

29. The computer program of claim 23,

said comparing source code segment further comparing the set of discrete RF characteristics from the mobile terminal with the set of discrete RF attributes for each of the plurality of sub-cells and a waveform from the mobile terminal with at least one signature waveform for each of the plurality of sub-cells;

said identifying source code segment identifying the sub-cell of the plurality of sub-cells whose set of discrete RF attributes and at least one signature waveform most closely match the set of discrete RF characteristics and the waveform from the mobile terminal as the sub-cell in which the mobile terminal is located.

30. The computer program of claim 23, wherein the set of discrete RF characteristics from the mobile terminal include pilot information.

31. The computer program of claim 30, wherein the pilot information includes at least one of pilot strength information, pilot strength ratio information, observed pilot strength information, average pilot strength information, and chip offset.

32. The computer program of claim 23, said identifying source code segment utilizing conditional probability to identify the sub-cell of the plurality of sub-cells whose set of RF attributes most closely match the set of RF characteristics from the mobile terminal.

33. The computer program of claim 32, wherein the conditional probability includes Bayes Theorem.

34. A computer data signal for identifying a geographical location of a mobile terminal, comprising:

a comparing signal segment for comparing a set of discrete RF characteristics from the mobile terminal with a set of discrete RF attributes for each of a plurality of sub-cells; and

an identifying signal segment for identifying a sub-cell of the plurality of sub-cells whose set of discrete RF attributes most closely match the set of discrete RF characteristics from the mobile terminal as the sub-cell in which the mobile terminal is located.

35. The computer data signal of claim 34, wherein the set of discrete RF attributes for each of the plurality of sub-cells is stored at a mobile system base station or at a mobile switching center.

36. The computer data signal of claim 35, wherein only one mobile system base station is required to identify the location of the mobile terminal.

37. The computer data signal of claim 34, wherein the comparing and identifying signal segments utilize pattern recognition.

38. The computer data signal of claim 34, wherein the set of discrete RF attributes for each of the plurality of sub-cells vary based on weather conditions, time of day, and environmental factors.

39. The computer data signal of claim 34, wherein said comparing and identifying signal segments are repeated over time as the mobile terminal moves.

40. The computer data signal of claim 34,

said comparing signal segment further comparing the set of discrete RF characteristics from the mobile terminal with the set of discrete RF attributes for each of the plurality of sub-cells and a waveform from the mobile terminal with at least one signature waveform for each of the plurality of sub-cells; said identifying signal segment identifying the sub-cell of the plurality of sub-cells whose set of discrete RF attributes and at least one signature waveform most closely match the set of discrete RF characteristics and the waveform from the mobile terminal as the sub-cell in which the mobile terminal is located.

41. The computer data signal of claim 34, wherein the computer data signal is embodied in a carrier wave.

42. The computer data signal of claim 34, wherein the set of discrete RF characteristics from the mobile terminal include pilot information.

43. The computer data signal of claim 42, wherein the pilot information includes at least one of pilot strength information, pilot strength ratio information, observed pilot strength information, average pilot strength information, and chip offset.

44. The computer data signal of claim 34, said identifying signal segment utilizes conditional probability to identify the sub-cell of the plurality of sub-cells whose set of RF attributes most closely match the set of RF characteristics from the mobile terminal.

45. The computer data signal of claim 44, wherein the conditional probability includes Bayes Theorem.

46. A computer data signal for identifying a geographical location of a mobile terminal, comprising:

a comparing signal segment for comparing a waveform from the mobile terminal with at least one signature waveform for each of a plurality of sub-cells; and

an identifying signal segment for identifying a sub-cell of the plurality of sub-cells whose at least one waveform most closely matches the waveform from the mobile terminal as the sub-cell in which the mobile terminal is located,

wherein the comparing and identifying signal segments utilize fuzzy logic and the computer data signal is embodied in a carrier wave.