Method and system for using a wireless signal received via a repeater for location determination

• US 7,822,427 B1
• Filed: 10/06/2006
• Issued: 10/26/2010
• Est. Priority Date: 10/06/2006
• Status: Active Grant

• Current Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Original Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Inventors: Hou, Jiongkuan
• Primary Examiner(s): Kincaid; Lester
• Assistant Examiner(s): Batista; Marcos
• Application Number:
  US11/544,682
• Time in Patent Office: 1,481 Days
• Field of Search: 455/456.1, 455/456.2, 455/13.1, 455/561
• US Class Current: 455/456.2
• CPC Class Codes: H04W 36/385 of the core network
• CPC Class Codes: H04W 64/006 with additional information processing, e.g. for direction or speed determination

Abstract

A base station almanac (BSA) includes entries for a plurality of repeaters. An entry for a repeater includes location-determination parameters associated with that repeater, such as (i) a repeater forward link calibration (FLC) value that correct for transmission delay associated with the repeater and (ii) a center point of the repeater'"'"'s coverage area. A measured power level and a measured phase of a wireless signal transmitted by a base transceiver station (BTS) and received by the mobile station are obtained. An expected received power level is calculated based on the measured phase and the transmit power level of the BTS. If the measured power level exceeds the expected received power level by at least a predetermined amount, then it is determined that the mobile station received the wireless signal via a repeater and one or more location-determination parameters associated with the repeater are used to determine the mobile station'"'"'s location.

Claims

1. A method for mobile station location determination, said method comprising:

obtaining a measured power level and a measured phase of a wireless signal received by a mobile station;

calculating an expected received power level for said wireless signal based on said measured phase;

comparing said expected received power level to said measured power level to determine that said mobile station received said wireless signal via a repeater;

obtaining at least one location-determination parameter associated with said repeater; and

determining a location of said mobile station using said at least one location-determination parameter.

2. The method of claim 1, wherein said wireless signal is a pilot signal transmitted by a base transceiver station (BTS).

3. The method of claim 1, further comprising:

identifying a signal source associated with said wireless signal.

4. The method of claim 3, further comprising:

looking up said signal source in a base station almanac (BSA) to determine whether said signal source is associated with any repeater.

5. The method of claim 4, wherein calculating an expected received power level for said wireless signal based on said measured phase comprises:

calculating a transmission delay from said measured phase;

obtaining a transmit power level of said signal source; and

applying a path loss model that predicts said expected received power level based on said transmit power level and said transmission delay.

6. The method of claim 5, wherein obtaining a transmit power level of said signal source comprises:

looking up said signal source in said BSA to find said transmit power level.

7. The method of claim 1, further comprising:

determining that said measured power level exceeds said expected received power level by at least a predetermined amount.

8. The method of claim 1, wherein said at least one location-determination parameter includes a forward link calibration (FLC) value that corrects for transmission delay associated with said repeater.

9. The method of claim 8, wherein determining a location of said mobile station using said at least one location-determination parameter comprises:

using said FLC value to correct said measured phase in an advanced forward link trilateration (AFLT) or hybrid positioning algorithm.

10. The method of claim 1, wherein said at least one location-determination parameter includes a repeater coverage area center point.

11. The method of claim 10, wherein determining a location of said mobile station using said at least one location-determination parameter comprises:

using said repeater coverage area center point as said location of said mobile station.

12. A system for mobile station location determination, said system comprising:

data storage storing location-determination information, wherein said location-determination information includes location-determination parameters for a plurality of repeaters; and

a location engine for determining locations of mobile stations using said location-determination information, said location engine being configured to (i) calculate an expected received power level of a wireless signal based on a measured phase of said wireless signal reported by a mobile station and (ii) compare said expected received power level to a measured power level reported by said mobile station to determine whether said mobile station received said wireless signal via one of said repeaters.

13. The system of claim 12, wherein said location-determination information is a base station almanac (BSA).

14. The system of claim 12, wherein said location-determination parameters include repeater forward link calibration (FLC) values.

15. The system of claim 12, wherein said location-determination parameters include repeater coverage area center points.