Systems and methods for mobile terminal location determination using profiles of radio signal parameter measurements

• US 8,463,285 B2
• Filed: 04/10/2006
• Issued: 06/11/2013
• Est. Priority Date: 04/08/2005
• Status: Active Grant

• Current Assignee: Smith Micro Software Incorporated
• Original Assignee: Wavemarket Incorporated (Gen Digital Inc.)
• Inventors: Drane, Christopher Ridgway, Scott, Craig Andrew, MacNaughtan, Malcolm, Brown, Stephen
• Primary Examiner(s): Bost, Dwayne
• Assistant Examiner(s): Johnson, Gerald
• Application Number:
  US11/887,948
• Publication Number:
  US 20090075651A1
• Time in Patent Office: 2,619 Days
• Field of Search: 455/456.1
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station
• CPC Class Codes: G01S 5/02525 Gathering the radio frequency fingerprints
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

Methods and systems for determining whether a mobile radio terminal is on or out of a zone in a radio communications network. The methods and systems provide for generating a profile representative of the zone using measurements taken by the mobile radio terminal and/or the network and/or using predicted values. A comparison is then made between subsequent measurements or values and the profile to make a determination as to whether the mobile radio terminal is in or out of the zone. The methods and systems are applicable to any zone-based application including differential call charging, security applications, buddy finder services, mobile gaming and location based services in general.

Claims

1. A method for generating a profile representative of a region expressed as one or more geographic coordinates about a mobile radio terminal in a radio communications network, the method comprising:

correlating the one or more geographic coordinates with one or more cell sites of the radio communications network;

predicting one or more radio signal parameter values and/or ranges in the correlated one or more cell sites;

obtaining at least one value of a first plurality of radio signal parameters from the region about the mobile radio terminal at a controlled rate from the mobile radio terminal, wherein the radio communications network controls the rate at which the mobile radio terminal transmits the at least one value of the first plurality of radio signal parameters from the region about the mobile radio terminal to the radio communications network for controlling a communications load on the radio communications network;

processing the at least one value of the first plurality of radio signal parameters to generate the profile representative of the region about the mobile radio terminal based at least in part on the predicted one or more radio signal parameter values and/or ranges in the correlated one or more cell sites; and

communicating the profile to a processor;

such that the processor is enabled to compare the profile with at least one value of a second plurality of radio signal parameters obtained at another mobile radio terminal to determine whether the another mobile radio terminal is within the region.

2. A method as claimed in claim 1 wherein the at least one value of the first plurality of radio signal parameters is obtained by the mobile radio terminal.

3. A method as claimed in claim 1 wherein the at least one value of the first plurality of radio signal parameters is obtained by a radio communications network device in the region about the mobile radio terminal.

4. A method as claimed in claim 1 wherein the at least one value of the first plurality of radio signal parameters is obtained by intercepting a communication between the mobile radio terminal and the radio communications network.

5. A method as claimed in claim 1 wherein at least one of the first plurality of radio signal parameters is a cell ID.

6. A method as claimed in claim 1 wherein the step of processing the at least one value of the first plurality of radio signal parameters is performed at the mobile radio terminal.

7. A method as claimed in claim 1 wherein the step of processing the at least one value of the first plurality of radio signal parameters is performed at a network processor of the radio communications network.

8. A method as claimed in claim 7 wherein the at least one value of the first plurality of radio signal parameters are transmitted from the mobile radio terminal to the network processor for processing to generate the profile.

9. A method as claimed in claim 1 wherein the step of processing the at least one value of the first plurality of radio signal parameters is performed at a processor external to the radio communications network.

10. A method as claimed in claim 9 wherein the at least one value of the first plurality of radio signal parameters are transmitted from the mobile radio terminal to the processor external to the radio communication network for processing to generate the profile.

11. A method as claimed in claim 1 wherein the processor is:

at a radio communication network element, external to the radio communications network, or in the mobile radio terminal.

12. A method as claimed in claim 1 wherein the step of processing the at least one value of the first plurality of radio signal parameters comprises averaging a plurality of values.

13. A method as claimed in claim 1 wherein the first plurality of radio signal parameters comprises one or more of a channel frequency identifier and an identifying code.

14. A method as claimed in claim 13 wherein the radio communications network is a GSM system and the channel, frequency identifier is the Absolute Radio Frequency Channel Numbers (ARFCN) and the identifying code is a Base Station Identity Code (BSTC).

15. A method as claimed in claim 1 wherein the at least one value of the first plurality of radio signal parameters is validated.

16. A method as claimed in claim 15 wherein the step of validating comprises calculating an approximate location of the mobile radio terminal and comparing the approximate location with a location associated with the region represented by the generated profile.

17. A method as claimed in claim 16 wherein if the approximate location of the mobile radio terminal and the location associated with the region are within a given distance of each other, accepting the at least one measurement, otherwise rejecting the at least one measurement.

18. A method as claimed in claim 1 wherein the step of obtaining the at least one value of the first plurality of radio signal parameters is controlled to control the extent of the region.

19. A method as claimed in claim 18 wherein the step of obtaining the at least one value of the first plurality of radio signal parameters is controlled by controlling a period of time during which the at least one value of the first plurality of radio signal parameters are obtained.

20. A method as claimed in claim 18 wherein the step of obtaining the at least one value of the first plurality of radio signal parameters is controlled by an external operator.

21. A method as claimed in claim 1 wherein at least one of the first plurality of radio signal parameters is an ambiguous radio signal parameter and at least one of the first plurality of radio signal parameters is an unambiguous radio signal parameter.

22. A method as claimed in claim 1 wherein at least one of the at least one values of the first plurality of radio signal parameters is obtained by measurement.

23. A method as claimed in claim 1 wherein at least one of the at least one values of the first plurality of radio signal parameters is predicted.

24. A system configured to perform the method of claim 1.

25. A machine readable medium containing instructions to cause a machine to perform the method of claim 1.

29. A method as claimed in claim 24 wherein the step of comparing the profile representing the predefined region with the at least one value of the second plurality of radio signal parameters is conducted at a processor external to the radio communications network element.

26. A method for determining whether a mobile radio terminal is within a predefined region of a radio communications network expressed as one or more geographic coordinates, the method comprising:

correlating the one or more geographic coordinates with one or more cell sites of the radio communications network;

predicting one or more radio signal parameter values and/or ranges in the correlated one or more cell sites;

obtaining a profile representing the predefined region of a radio communications network based at least in part on the predicted one or more radio signal parameter values and/or ranges in the correlated one or more cell sites, wherein the profile includes at least one value of a first plurality of radio signal parameters obtained at a controlled rate from the mobile radio terminal, wherein the radio communications network controls the rate at which the mobile radio terminal transmits the at least one value of the first plurality of radio signal parameters from the mobile radio terminal to the radio communications network for controlling a communications load on the radio communications network;

obtaining at least one value of a second plurality of radio signal parameters from a region about another mobile radio terminal;

comparing the profile representing the predefined region with the at least one value of the second plurality of radio signal parameters corresponding to the another mobile radio terminal; and

determining whether the another mobile radio terminal is within the predefined region on the basis of the comparison.

27. A method as claimed in claim 26 wherein the step of comparing the profile representing the predefined region with the at least one value of the second plurality of radio signal parameters is conducted by the mobile radio terminal.

28. A method as claimed in claim 26 wherein the step of comparing the profile representing the predefined region with the at least one value of the second plurality of radio signal parameters is conducted at a radio communications network element.

30. A method as claimed in claim 26 wherein there are a plurality of predefined regions, each having a respective representative profile.

31. A method as claimed in claim 30 wherein two or more of the plurality of predefined regions overlap.

32. A method as claimed in claim 31 wherein the at least one value of the second plurality of radio signal parameters is transmitted upon receiving a request from the radio communications network.

33. A method as claimed in claim 31 wherein the at least one value of the second plurality of radio signal parameters is transmitted upon receiving a request from a processor external to the radio communications network.

34. A method as claimed in claim 26 wherein least one of the at least one value of the second plurality of radio signal parameters is obtained by measurement.

35. A method as claimed in claim 34 wherein the at least one value of the second plurality of radio signal parameters is transmitted upon the user of the another mobile radio terminal initiating a call.

36. A method as claimed in claim 26 wherein least one of the at least one value of the second plurality of radio signal parameters is predicted.

37. The method of claim 26 further comprising the step of:

transmitting from the another mobile radio terminal, the at least one value of the second plurality of radio signal parameters to a processor for comparison with the profile of the predefined region.

38. A method as claimed in claim 37 wherein the at least one value of the second plurality of radio signal parameters is transmitted upon initiation by a user of the another mobile radio terminal.

39. The method of claim 26 further comprising the step of:

transmitting the determination to a processor.

40. A method as claimed in claim 39 wherein the processor is a processor in the radio communications network.

41. A method as claimed in claim 39 wherein the processor is a processor external to the radio communications network.

42. A method as claimed in claim 39 wherein the determination is transmitted to the processor upon initiation by a user of the mobile radio terminal.

43. A method as claimed in claim 39 wherein the determination is transmitted to the processor upon the user of the mobile radio terminal initiating a call.

44. A method as claimed in claim 39 wherein the determination is transmitted to the processor upon receiving a request from the radio communications network.

45. A method as claimed in claim 39 wherein the determination is transmitted to the processor upon receiving a request from external to the radio communications network.

46. A method as claimed in claim 39 wherein the determination is transmitted to the processor upon a change of the determination.

47. A method as claimed in claim 26 wherein the step of comparing comprises:

calculating a cost C associated with the at least one value of the second plurality of radio signal parameters and the profile; and

comparing the cost C with a threshold.

48. A method as claimed in claim 47 wherein the cost C is calculated as follows:

C=C_m+C_um+C_ur

where

C_m=Cost associated with cells that are observed and are matched in the profile

C_um=Cost associated with cells that are observed but are not matched in the profile

C_ur=Cost associated with cells that are in the profile but are not reported.

49. A method as claimed in claim 48 wherein each of C_m, C_um and C_ur are calculated as follows:

50. A method as claimed in claim 48 wherein:

C<

χ

² (x, N_T−

2) than in Zone

otherwise, not in Zone,

where

χ

² is the standard statistical function,

N_T=N_m+N_um+N_ur

x=a percentage between 0 and 100.

51. The method of claim 26 further comprising:

associating a threshold with a ratio of a probability of an Out-Given-In error and a probability of an In-Given-Out error; and

adjusting the threshold to achieve a desired performance.

52. A method as claimed in claim 51 whereinthe threshold may be adjusted from about 0% to about 100%.

53. A method as claimed in claim 51 wherein the size of the region increases as the probability of in-given-out errors increases.

54. A method as claimed in claim 26 wherein the mobile radio terminal transmits data relating to radio signal parameters about the mobile radio terminal.