Sparsed U-TDOA wireless location networks

• US 8,041,367 B2
• Filed: 04/18/2007
• Issued: 10/18/2011
• Est. Priority Date: 04/18/2007
• Status: Active Grant

• Current Assignee: Skyhook Holding, Inc. (Liberty Broadband Corp.)
• Original Assignee: TruePosition Incorporated
• Inventors: Anderson, Robert J., Ward, Matthew L.
• Primary Examiner(s): Afshar; Kamran
• Assistant Examiner(s): Zewari; Sayed T
• Application Number:
  US11/736,920
• Publication Number:
  US 20080261613A1
• Time in Patent Office: 1,644 Days
• Field of Search: 455/456.1, 4554221-460, 455524-525, 455/509, 455/464, 370/328, 370/329
• US Class Current: 455/456.1
• CPC Class Codes: H04W 16/18 Network planning tools
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

In an overlay, U-TDOA-based, Wireless Location System, LMUs typically co-located with BTSs, are used to collect radio signaling both in the forward and reverse channels. Techniques are used to compensate for sparse LMU deployments where sections of the U-TDOA service area are uplink demodulation or downlink beacon discovery limited.

Claims

1. A computer-implemented method for designing a sparse wireless location system (WLS) from an initial network design, wherein the sparse WLS is designed to be overlaid on a wireless communications system, comprising:

performing an intelligent WLS network design process to produce an initial network design;

storing the initial network design on a non-transitory computer readable medium;

determining that the initial network design is affected by an accuracy performance limiting factor;

modifying the initial network design by performing at least one of the following actions;

increasing an integration time at one or more location measuring units (LMUs);

deploying a hybrid time difference of arrival (TDOA)/ enhanced cell identification (ECID) location process in the WLS;

deploying a hybrid time TDOA/ angle of arrival (AoA) location process in the WLS; and

adding at least one LMU to the network design; and

saving the modified network design on the computer readable medium;

wherein said WLS comprises an uplink time difference of arrival (U-TDOA) system including a plurality of geographically dispersed location measuring units (LMUs); and

wherein said WLS is overlaid on a wireless communications system comprising a plurality of geographically dispersed bas e transceiver stations (BTSs).

2. A method as recited in claim 1, further comprising determining that the initial network design or a modified version thereof is affected by a downlink beacon discovery performance limiting factor.

3. A method as recited in claim 2, further comprising the following step based on the determination that the performance limiting factor is downlink beacon discovery:

deploying at least one enhanced downlink antenna.

4. A method as recited in claim 2, further comprising the following step based on the determination that the performance limiting factor is downlink beacon discovery:

deploying downlink interference cancellation.

5. A method as recited in claim 2, further comprising the following step based on the determination that the performance limiting factor is downlink beacon discovery:

deploying base transceiver station (BTS) synchronization.

6. A method as recited in claim 2, further comprising the following step based on the determination that the performance limiting factor is downlink beacon discovery:

adding at least one location measuring unit (LMU) to the network design.

7. A method as recited in claim 2, further comprising the following step based on the determination that the performance limiting factor is downlink beacon discovery:

determining that an Abis monitoring system (AMS) is not deployed, and then deploying at least one downlink-only location measuring unit (LMU) at an identified site.

8. A method as recited in claim 2, further comprising the following step based on the determination that the performance limiting factor is downlink beacon discovery:

determining that an Abis monitoring system (AMS) is deployed, and then enabling the use of Enhanced Beacon Synchronization (EBS) and AMS-derived beacon timing functions.

9. A method as recited in claim 1, further comprising determining that the initial network design or a modified version thereof is affected by an uplink demodulation performance limiting factor.

10. A method as recited in claim 9, further comprising the following step based on the determination that the performance limiting factor affecting the initial network design is uplink demodulation:

determining that communications system demodulation data is enabled, and enabling a demodulated data feature.

11. A method as recited in claim 9, further comprising the following step based on the determination that the performance limiting factor affecting the initial network design is uplink demodulation:

determining that communications system demodulation data is not enabled, and determining that an Abis monitoring system (AMS) is not deployed and enabling a mid-amble only correction feature.

12. A method as recited in claim 9, further comprising the following step based on the determination that the performance limiting factor affecting the initial network design is uplink demodulation:

determining that communications system demodulation data is not enabled, and determining that an Abis monitoring system (AMS) is deployed and enabling an AMS-derived demodulated data feature.

13. A method as recited in claim 9, further comprising the following step based on the determination that the performance limiting factor affecting the initial network design is uplink demodulation:

adding at least one location measuring unit (LMU) to the network design.

14. A method as recited in claim 9, further comprising the following step based on the determination that the performance limiting factor affecting the initial network design is uplink demodulation:

adding at least one dedicated antenna facility to the network design.

15. A computer readable medium comprising computer readable instructions for carrying out a prescribed method for designing a sparse wireless location system (WLS) from an initial network design, wherein the initial network design is produced by an intelligent network design process, wherein said WLS comprises an uplink time difference of arrival (U-TDOA) system including a plurality of geographically dispersed location measuring units (LMUs), and wherein said WLS is overlaid on a wireless communications system comprising a plurality of geographically dispersed base transceiver stations (BTSs), said method comprising:

determining that the initial network design is affected by an accuracy performance limiting factor; and

modifying the initial network design by performing at least one of the following actions;

increasing an integration time at one or more location measuring units (LMUs);

deploying a hybrid time difference of arrival (TDOA)/ enhanced cell identification (ECID) location process in the WLS;

deploying a hybrid time TDOA/ angle of arrival (AoA) location process in the WLS; and

adding at least one LMU to the network design.

16. A computer readable medium as recited in claim 15, wherein said method further comprises determining that the initial network design or a modified version thereof is affected by a downlink beacon discovery performance limiting factor.

17. A computer readable medium as recited in claim 16, wherein said method further comprises the following step based on the determination that the performance limiting factor is downlink beacon discovery:

deploying at least one enhanced downlink antenna.

18. A computer readable medium as recited in claim 16, wherein said method further comprises the following step based on the determination that the performance limiting factor is downlink beacon discovery:

deploying downlink interference cancellation.

19. A computer readable medium as recited in claim 16, wherein said method further comprises the following step based on the determination that the performance limiting factor is downlink beacon discovery:

deploying base transceiver station (BTS) synchronization.

20. A computer readable medium as recited in claim 16, wherein said method further comprises the following step based on the determination that the performance limiting factor is downlink beacon discovery:

adding at least one location measuring unit (LMU) to the network design.

21. A computer readable medium as recited in claim 16, wherein said method further comprises the following step based on the determination that the performance limiting factor is downlink beacon discovery:

determining that an Abis monitoring system (AMS) is not deployed, and then deploying at least one downlink-only location measuring unit (LMU) at an identified site.

22. A computer readable medium as recited in claim 16, wherein said method further comprises the following step based on the determination that the performance limiting factor is downlink beacon discovery:

determining that an Abis monitoring system (AMS) is deployed, and then enabling the use of Enhanced Beacon Synchronization (EBS) and AMS-derived beacon timing functions.

23. A computer readable medium as recited in claim 15, wherein said method further comprises determining that the initial network design or a modified version thereof is affected by an uplink demodulation performance limiting factor.

24. A computer readable medium as recited in claim 23, wherein said method further comprises the following step based on the determination that the performance limiting factor affecting the initial network design is uplink demodulation:

determining that communications system demodulation data is enabled, and enabling a demodulated data feature.

25. A computer readable medium as recited in claim 23, wherein said method further comprises the following step based on the determination that the performance limiting factor affecting the initial network design is uplink demodulation:

determining that communications system demodulation data is not enabled, and determining that an Abis monitoring system (AMS) is not deployed and enabling a mid-amble only correction feature.

26. A computer readable medium as recited in claim 23, wherein said method further comprises the following step based on the determination that the performance limiting factor affecting the initial network design is uplink demodulation:

determining that communications system demodulation data is not enabled, and determining that an Abis monitoring system (AMS) is deployed and enabling an AMS-derived demodulated data feature.

27. A computer readable medium as recited in claim 23, wherein said method further comprises the following step based on the determination that the performance limiting factor affecting the initial network design is uplink demodulation:

adding at least one location measuring unit (LMU) to the network design.

28. A computer readable medium as recited in claim 23, wherein said method further comprises the following step based on the determination that the performance limiting factor affecting the initial network design is uplink demodulation:

adding at least one dedicated antenna facility to the network design.