Femto-cell location by proxy methods

• US 8,200,239 B2
• Filed: 11/11/2008
• Issued: 06/12/2012
• Est. Priority Date: 11/11/2008
• Status: Active Grant

• Current Assignee: Skyhook Holding, Inc. (Liberty Broadband Corp.)
• Original Assignee: TruePosition Incorporated
• Inventors: Mia, Rashidus S., Anderson, Robert J., Ward, Matthew L.
• Primary Examiner(s): Corsaro, Nick
• Assistant Examiner(s): Mapa, Michael
• Application Number:
  US12/269,000
• Publication Number:
  US 20100120394A1
• Time in Patent Office: 1,309 Days
• Field of Search: 4554561-458, 455/404.2, 455/444, 455/449
• US Class Current: 455/456.1
• 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

Location of small, consumer deployed femto-cells cannot be determined by the usual site survey methods. Location of attached mobiles allows for a proxy location of the femto-cell that can then be used for wireless network planning including the provisioning of a calculated default emergency services location for the femto-cell.

Claims

1. 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:

(a) 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) storing the femto-cell ID information in the SMLC database;

(c) setting a trigger for location of the femto-cell device, 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) determining an identification of a MS being served by the femto-cell device;

(e) determining the location of the MS and providing MS location information to the SMLC database;

(f) calculating the location of the femto-cell device using the location of the MS;

(g) calculating a confidence factor relating to the calculated location of the femto-cell device;

(h) comparing the calculated confidence factor with a confidence factor stored in the SMLC database;

(i) determining that the calculated confidence factor is better than the stored confidence factor; and

(j) taking a further action including at least one of;

notifying an operator of the wireless communications system of an error in stored location information associated with the femto-cell device; and

updating the location information associated with the femto-cell device in the SMLC database.

2. A method as recited in claim 1, 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.

3. A method as recited in claim 1, further comprising use of the femto-cell device location for radio frequency (RF) planning and coordination.

4. A method as recited in claim 3, 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.

5. A method as recited in claim 1, further comprising use of the femto-cell device location for emergency services.

6. A method as recited in claim 1, further comprising use of the femto-cell device location for warning, alert and response network (WARN) services.

7. A method as recited in claim 1, further comprising use of the femto-cell device location for commercial location services.

8. A method as recited in claim 1, further comprising determining a distance separating the femto-cell device from the MS, and calculating the location of the femto-cell device using the location of the MS and the distance separating the femto-cell device from the MS.

9. A method as recited in claim 1, wherein the wireless communications system comprises, in addition to said femto-cell device, a plurality of macro-cells and at least one micro-cell.

10. A method as recited in claim 9, wherein said femto-cell device is an under-lay femto-cell situated within a radio footprint of a single macro-cell.

11. A method as recited in claim 9, wherein said femto-cell device is a border femto-cell situated within the radio footprints of multiple macro-cells.

12. A method as recited in claim 9, wherein said femto-cell device is a remote femto-cell situated outside the radio footprint and coverage areas of all macro-cells of the wireless communications system.

13. A method as recited in claim 1, wherein the location of the MS is calculated by the MS and provided by the MS.

14. A method as recited in claim 13, wherein the MS is a Global Navigation Satellite System (GNSS)-capable device comprising a receiver capable of receiving GNSS satellite signals.

15. A method as recited in claim 1, wherein the location of the MS is calculated by a network-based wireless location system.

16. A method as recited in claim 15, wherein the location of the MS is determined using MS uplink transmissions during a handover procedure.

17. 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) means 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) means for storing the femto-cell ID information in the SMLC database;

(c) means for setting a trigger for location of the femto-cell device, 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) means for determining an identification of a MS being served by the femto-cell device;

(e) means for determining the location of the MS and providing MS location information to the SMLC database;

(f) means for calculating the location of the femto-cell device using the location of the MS;

(g) means for calculating a confidence factor relating to the calculated location of the femto-cell device; and

(h) means for comparing the calculated confidence factor with a confidence factor stored in the SMLC database.

18. A subsystem as recited in claim 17, further comprising means for determining that the calculated confidence factor is better than the stored confidence factor, and updating location information associated with the femto-cell device in the SMLC database.

19. A subsystem as recited in claim 17, further comprising means 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.

20. A subsystem as recited in claim 17, further comprising means 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.

21. A subsystem as recited in claim 17, further comprising means for determining a distance separating the femto-cell device from the MS, and means for calculating the location of the femto-cell device using the location of the MS and the distance separating the femto-cell device from the MS.

22. A subsystem as recited in claim 17, wherein the location of the MS is calculated by the MS and provided by the MS.

23. A subsystem as recited in claim 17, wherein the location of the MS is calculated by the WLS.

24. A subsystem as recited in claim 23, wherein the location of the MS is determined using MS uplink transmissions during a handover procedure.