Sparsed U-TDOA Wireless Location Networks

• US 20080261612A1
• Filed: 04/18/2007
• Published: 10/23/2008
• 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., Mia, Rashidus S.
• Granted Patent: US 8,242,959 B2
• Time in Patent Office: Days
• 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 method for designing a sparse wireless location system (WLS) from an initial network design, comprising:

determining that the initial network design is affected by a downlink beacon discovery performance limiting factor; and

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

deploying at least one enhanced downlink antenna;

deploying downlink interference cancellation;

deploying base transceiver station (BTS) synchronization;

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

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;

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.

2. A method as recited in claim 1, wherein said WLS comprises an uplink time difference of arrival (U-TDOA) system including a plurality of geographically dispersed location measuring units (LMUs).

3. A method as recited in claim 1, wherein said WLS is overlaid on a GSM wireless communications system comprising a plurality of geographically dispersed base transceiver stations (BTSs).

4. A method as recited in claim 1, further comprising identifying at least one cluster of co-synchronized cell sectors and performing an intelligent network design process to produce said initial network design.

5. A method as recited in claim 2, further comprising determining that the initial network design or a modified version thereof is affected by an accuracy performance limiting factor, and modifying the 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.

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

7. 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, 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.

8. 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, 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.

9. A method as recited in claim 2, further comprising determining that the initial network design or a modified version thereof is affected by an uplink demodulation performance limiting factor, and adding at least one location measuring unit (LMU) to the network design.

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

11. 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, said prescribed method comprising:

determining that the initial network design is affected by a downlink beacon discovery performance limiting factor; and

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

deploying at least one enhanced downlink antenna;

deploying downlink interference cancellation;

deploying base transceiver station (BTS) synchronization;

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

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;

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.

12. A computer readable medium as recited in claim 11, wherein said WLS comprises an uplink time difference of arrival (U-TDOA) system including a plurality of geographically dispersed location measuring units (LMUs).

13. A computer readable medium as recited in claim 11, wherein said WLS is overlaid on a GSM wireless communications system comprising a plurality of geographically dispersed base transceiver stations (BTSs).

14. A computer readable medium as recited in claim 11, wherein said prescribed method further comprises identifying at least one cluster of co-synchronized cell sectors and performing an intelligent network design process to produce said initial network design.

15. A computer readable medium as recited in claim 11, wherein said prescribed method further comprises determining that the initial network design or a modified version thereof is affected by an accuracy performance limiting factor, and modifying the 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 11, wherein said prescribed method further comprises determining that the initial network design or a modified version thereof is affected by an uplink demodulation performance limiting factor, determining that communications system demodulation data is enabled, and enabling a demodulated data feature.

17. A computer readable medium as recited in claim 11, wherein said prescribed method further comprises determining that the initial network design or a modified version thereof is affected by an uplink demodulation performance limiting factor, 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.

18. A computer readable medium as recited in claim 11, wherein said prescribed method further comprises determining that the initial network design or a modified version thereof is affected by an uplink demodulation performance limiting factor, 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.

19. A computer readable medium as recited in claim 11, wherein said prescribed method further comprises determining that the initial network design or a modified version thereof is affected by an uplink demodulation performance limiting factor, and adding at least one location measuring unit (LMU) to the network design.

20. A computer readable medium as recited in claim 11, wherein said prescribed method further comprises determining that the initial network design or a modified version thereof is affected by an uplink demodulation performance limiting factor, and adding at least one dedicated antenna facility to the network design.