Femto-Cell Location by Direct Methods

• US 20100120447A1
• Filed: 11/11/2008
• Published: 05/13/2010
• Est. Priority Date: 11/11/2008
• Status: Active Grant

• Current Assignee: Skyhook Holding, Inc. (Liberty Broadband Corp.)
• Original Assignee: TruePosition Incorporated
• Inventors: Anderson, Robert J., Mia, Rashidus S., Ward, Matthew L.
• Granted Patent: US 8,180,368 B2
• Time in Patent Office: Days
• US Class Current: 455/456.100
• CPC Class Codes: G01S 5/0242 Determining the position of transmitters to be subsequently used in positioning G01S5/0289 takes precedence
• CPC Class Codes: H04W 64/003 locating network equipment
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B

Abstract

Illustrative embodiments of the inventive subject matter described herein include, but are not limited to, the following: a femto-cell device, methods for use by a wireless location system (WLS) in locating a femto-cell device, and a wireless location system having certain features relating to the location of femto-cell devices. A femto-cell device used in a wireless communications system (WCS) includes a location subsystem configured to acquire information identifying the geographic location of the femto-cell device. The device also includes an antenna subsystem, a radio frequency (RF) block coupled to the antenna subsystem, a baseband block coupled to the RF block, and a communications block coupled to the baseband block. In addition, the device is configured to communicate with the WCS, including communicating at least some of the location information to the WCS.

Claims

1. A femto-cell device for use in a wireless communications system (WCS), comprising:

a location subsystem configured to acquire information identifying the geographic location of the femto-cell device;

an antenna subsystem;

a radio frequency (RF) block coupled to said antenna subsystem;

a baseband block coupled to said RF block;

a communications block coupled to said baseband block; and

a communications subsystem configured to communicate with the WCS, including communicating at least some of the location information to the WCS.

2. A femto-cell device as recited in claim 1, further comprising a triggering mechanism configured to actuate the location subsystem so as to cause the location subsystem to determine the geographic location of the femto-cell device.

3. A femto-cell device as recited in claim 2, wherein said triggering mechanism is configured to actuate the location subsystem in response to the femto-cell device being turned on.

4. A femto-cell device as recited in claim 2, wherein said triggering mechanism is configured to actuate the location subsystem periodically in response to a timer.

5. A femto-cell device as recited in claim 2, wherein said triggering mechanism is configured to actuate the location subsystem in response to a command from the WCS.

6. A femto-cell device as recited in claim 5, wherein said triggering mechanism is configured to actuate the location subsystem in response to a radio frequency command signal received from the WCS.

7. A femto-cell device as recited in claim 5, wherein said triggering mechanism is configured to actuate the location subsystem in response to a command signal received via a digital backhaul link to the WCS.

8. A femto-cell device as recited in claim 1, wherein said location subsystem includes a downlink receiver and is configured to acquire location information using downlink beacons from WCS base stations.

9. A femto-cell device as recited in claim 1, wherein said location subsystem includes a GPS receiver and is configured to acquire location information using GPS signals.

10. A femto-cell device as recited in claim 9, wherein said location subsystem is further configured to acquire GPS assistance information and to acquire GPS signals using said assistance information.

11. A femto-cell device as recited in claim 1, wherein said location subsystem includes a high definition television (HDTV) receiver and is configured to acquire location information using HDTV beacons.

12. A femto-cell device as recited in claim 8, wherein said location subsystem further includes a high definition television (HDTV) receiver and is configured to acquire location information using a hybrid of downlink WCS beacons and HDTV beacons.

13. A femto-cell device as recited in claim 1, wherein said location subsystem is configured to acquire location information from a mobile station (MS) being served by the femto-cell device and to use said location information to calculate the location of the femto-cell device.

14. A femto-cell device as recited in claim 1, wherein said communications subsystem is configured to communicate location information via a digital backhaul data link to the WCS.

15. A femto-cell device as recited in claim 1, wherein said communications subsystem is configured to communicate location information via a downlink beacon signal.

16. A femto-cell device as recited in claim 1, wherein said communications subsystem is configured to communicate location information via an uplink traffic channel signal.

17. A femto-cell device as recited in claim 1, wherein said communications subsystem is configured to communicate location information via an uplink access channel signal.

18. A method for use by a wireless location system (WLS) in locating a femto-cell device operating in a wireless communications system (WCS), comprising:

discovering and initiating location of the femto-cell device; and

determining the location of the femto-cell device.

19. A method as recited in claim 18, wherein initiating location of the femto-cell device comprises receiving a command from the WCS.

20. A method as recited in claim 18, wherein initiating location of the femto-cell device comprises receiving a wireless intelligent network trigger based on cell-ID information broadcast by the femto-cell device.

21. A method as recited in claim 18, wherein initiating location of the femto-cell device comprises detection of a new cell-ID.

22. A method as recited in claim 21, wherein the new cell-ID is detected by a radio network monitor (RNM) associated with the WLS.

23. A method as recited in claim 21, wherein the new cell-ID is detected by a link monitoring system (LMS) associated with the WLS.

24. A method as recited in claim 18, wherein the wireless communications system comprises, in addition to said femto-cell, a plurality of macro-cells and at least one micro-cell.

25. A method as recited in claim 24, wherein said femto-cell is an under-lay femto-cell situated within a radio footprint of a single macro-cell.

26. A method as recited in claim 24, wherein said femto-cell is a border femto-cell situated within the radio footprints of multiple macro-cells.

27. A method as recited in claim 24, wherein said femto-cell is a remote femto-cell situated outside the radio footprint and coverage areas of all macro-cells of the WCS.

28. A method as recited in claim 18, wherein the WLS includes a serving mobile location center (SMLC), a plurality of location measuring units (LMUs) in communication with the SMLC, a plurality of link monitors in communication with the SMLC, and a database in communication with the SMLC and containing cell locations and other radio aspects of the wireless communications system.

29. A method as recited in claim 18, wherein the location of the femto-cell is calculated by the femto-cell device and provided by the femto-cell device to the WLS.

30. A method as recited in claim 29, wherein the femto-cell device is a Global Navigation Satellite System (GNSS)-capable device comprising a receiver capable of receiving GNSS satellite signals.

31. A method as recited in claim 18, wherein the location of the femto-cell device is calculated by the WLS.

32. A method as recited in claim 31, wherein the location of the femto-cell device is determined using uplink transmissions during a handover procedure.

33. A method for use by a wireless location system (WLS) in locating a femto-cell device operating in a wireless communications system, wherein the WLS includes a serving mobile location center (SMLC), a plurality of location measuring units (LMUs) in communication with the SMLC, a plurality of link monitors in communication with the SMLC, and an SMLC database in communication with the SMLC and containing cell locations and other radio aspects of the wireless communications system, the method comprising:

discovering and initiating location of the femto-cell device, wherein said discovering and initiating comprises at least one of the following procedures;

(a1) receiving femto-cell ID information from the wireless communications system;

(a2) discovery of the femto-cell ID information via analysis of call detail records; and

(a3) discovery of the femto-cell ID information via monitoring of wireless communications system link traffic for new cell-IDs within messages related to call events;

storing femto-cell identification information in the SMLC database;

setting a trigger for location of the femto-cell, wherein said setting a trigger comprises at least one of the following procedures;

(c1) setting a femto-cell cell-ID trigger in the SMLC database via a wireless intelligent network (WIN) facility;

(c2) setting an internal femto-cell cell-ID trigger in the SMLC database to indicate to the WLS that mobile station (MS) location information should be examined to identify when the femto-cell device is serving the MS;

(c3) setting a femto-cell cell-ID trigger in a radio network monitor (RNM) or link monitoring system (LMS) associated with the WLS, wherein the WLS is configured such that detection of the femto-cell cell-ID provokes the WLS to attempt location of the femto-cell device;

determining the location of the femto-cell device and providing location information to the SMLC database;

calculating a confidence factor relating to the calculated location of the femto-cell device; and

comparing the calculated confidence factor with a confidence factor stored in the SMLC database.

34. A method as recited in claim 33, further comprising determining that the calculated confidence factor is better than the stored confidence factor, and updating location information in the SMLC database.

35. A method as recited in claim 33, further comprising determining that the calculated confidence factor is better than the stored confidence factor, and notifying an operator of the wireless communications system of an error in the stored location information associated with the femto-cell device.

36. A method as recited in claim 33, further comprising determining that the calculated confidence factor is below a prescribed value and attempting to obtain a more accurate location of the femto-cell device.

37. A method as recited in claim 33, further comprising use of the femto-cell location for RF planning and coordination.

38. A method as recited in claim 37, wherein said RF planning and coordination includes preventing the femto-cell device from interfering with other cells when the femto-cell device is re-located.

39. A method as recited in claim 33, further comprising use of the femto-cell location for emergency services.

40. A method as recited in claim 33, further comprising use of the femto-cell location for warning, alert and response network (WARN) services.

41. A method as recited in claim 33, further comprising use of the femto-cell location for commercial location services.

42. A method as recited in claim 33, wherein the wireless communications system comprises, in addition to said femto-cell, a plurality of macro-cells and at least one micro-cell.

43. A method as recited in claim 42, wherein said femto-cell device is deployed as an under-lay femto-cell situated within a radio footprint of a single macro-cell.

44. A method as recited in claim 42, wherein said femto-cell device is deployed as a border femto-cell situated within the radio footprints of multiple macro-cells.

45. A method as recited in claim 42, wherein said femto-cell device is deployed as a remote femto-cell situated outside the radio footprint and coverage areas of all macro-cells of the wireless communications system.

46. A method as recited in claim 33, wherein the location of the femto-cell device is calculated by the femto-cell device.

47. A method as recited in claim 46, wherein the femto-cell device is a Global Navigation Satellite System (GNSS)-capable device comprising a receiver capable of receiving GNSS satellite signals.

48. A method as recited in claim 33, wherein the location of the femto-cell device is calculated by the WLS.

49. A method as recited in claim 48, wherein the location of the femto-cell device is determined using uplink transmissions during a handover procedure.

50. A wireless location system (WLS), comprising:

a serving mobile location center (SMLC);

a plurality of location measuring units (LMUs) in communication with the SMLC;

a plurality of link monitors in communication with the SMLC;

an SMLC database in communication with the SMLC and containing cell locations and other radio aspects of the wireless communications system; and

a subsystem configured for locating a femto-cell device operating in the wireless communications system, including a subsystem configured for discovering and initiating location of the femto-cell device, and a subsystem configured for determining the location of the femto-cell device.

51. A WLS as recited in claim 50, wherein the a subsystem configured for initiating location of the femto-cell device comprises a subsystem configured for receiving a command from the wireless communications system.

52. A WLS as recited in claim 50, wherein the a subsystem configured for initiating location of the femto-cell device comprises a subsystem configured for receiving a wireless intelligent network trigger based on cell-ID information broadcast by the femto-cell device.

53. A WLS as recited in claim 50, wherein the subsystem configured for discovering and initiating location of the femto-cell device comprises a subsystem configured for detection of a new cell-ID.

54. A WLS as recited in claim 53, wherein the a subsystem configured for detection of a new cell-ID comprises a radio network monitor (RNM).

55. A WLS as recited in claim 53, wherein the subsystem configured for detection of a new cell-ID comprises a link monitoring system (LMS).

56. A WLS as recited in claim 50, wherein the wireless communications system comprises, in addition to said femto-cell, a plurality of macro-cells and at least one micro-cell.

57. A WLS as recited in claim 50, wherein the location of the femto-cell device is calculated by the femto-cell device.

58. A WLS as recited in claim 57, wherein the femto-cell device is a Global Navigation Satellite System (GNSS)-capable device comprising a receiver capable of receiving GNSS satellite signals.

59. A WLS as recited in claim 50, wherein the location of the femto-cell device is determined using uplink transmissions during a handover procedure.

60. A subsystem for use by a wireless location system (WLS) in locating a femto-cell device operating in a wireless communications system, wherein the WLS includes a serving mobile location center (SMLC), a plurality of location measuring units (LMUs) in communication with the SMLC, a plurality of link monitors in communication with the SMLC, and an SMLC database in communication with the SMLC and containing cell locations and other radio aspects of the wireless communications system, the subsystem comprising:

(a) a subsystem configured for discovering and initiating location of the femto-cell device, wherein said discovering and initiating comprises at least one of the following procedures;

(a1) receiving femto-cell ID information from the wireless communications system;

(a2) discovery of the femto-cell ID information via analysis of call detail records; and

(a3) discovery of the femto-cell ID information via monitoring of wireless communications system link traffic for new cell-IDs within messages related to call events;

(b) a subsystem configured for storing femto-cell identification information in the SMLC database;

(c) a subsystem configured for setting a trigger for location of the femto-cell, wherein said setting a trigger comprises at least one of the following procedures;

(c1) setting a femto-cell cell-ID trigger in the SMLC database via a wireless intelligent network (WIN) facility;

(c2) setting an internal femto-cell cell-ID trigger in the SMLC database to indicate to the WLS that mobile station (MS) location information should be examined to identify when the femto-cell device is serving the MS;

(c3) setting a femto-cell cell-ID trigger in a radio network monitor (RNM) or link monitoring system (LMS) associated with the WLS, wherein the WLS is configured such that detection of the femto-cell cell-ID provokes the WLS to attempt location of the femto-cell device;

(d) a subsystem configured for calculating the location of the femto-cell device;

(e) a subsystem configured for calculating a confidence factor relating to the calculated location of the femto-cell; and

(f) a subsystem configured for comparing the calculated confidence factor with a confidence factor stored in the SMLC database.

61. A subsystem as recited in claim 60, further comprising a subsystem configured for determining that the calculated confidence factor is better than the stored confidence factor, and in response thereto updating location information in the SMLC database.

62. A subsystem as recited in claim 60, further comprising a subsystem configured for determining that the calculated confidence factor is better than the stored confidence factor, and notifying an operator of the wireless communications system of an error in the stored location information associated with the femto-cell device.

63. A subsystem as recited in claim 60, further comprising a subsystem configured for determining that the calculated confidence factor is below a prescribed value and attempting to obtain a more accurate location of the femto-cell device.

64. A subsystem as recited in claim 60, wherein the location of the femto-cell device is calculated by the femto-cell device.

65. A subsystem as recited in claim 60, wherein the location of the femto-cell device is calculated by the femto-cell device.

66. A WLS as recited in claim 65, wherein the location of the femto-cell device is determined using uplink transmissions during a handover procedure.