Locating a mobile station inside a building

• US 7,860,518 B2
• Filed: 06/29/2007
• Issued: 12/28/2010
• Est. Priority Date: 11/17/2006
• Status: Expired due to Fees

• Current Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Original Assignee: Alcatel-Lucent USA, Inc. (Nokia Corporation)
• Inventors: Flanagan, Michael J., Pan, Vic, Nardozza, Gregg
• Primary Examiner(s): Afshar; Kamran
• Application Number:
  US11/770,957
• Publication Number:
  US 20080119208A1
• Time in Patent Office: 1,278 Days
• Field of Search: 4554561-457, 455/404.2, 455/442, 455 6711- 6713, 455/9, 455560-5621, 370331-332, 370/312, 370/328
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/02585 at least one of the measurements being a non-radio measurement
• CPC Class Codes: H04W 4/04 using association of physical positions and logical data in a dedicated environment, e.g. buildings or vehicles
• CPC Class Codes: H04W 4/33 for indoor environments, e.g. buildings
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

Locating mobile stations used for wireless communications even when the mobile station is within a building includes determining whether at least one indicator associated with a signal used by the mobile station identifies a single, known building location. Example types of indicators include a base station and sector identifier of a base station sector dedicated to a particular building, a delay associated with a radio frequency signal used by the mobile station when communicating from a particular building location or a combination of cell codes reported by a mobile station when it is within a particular building location. One or more of such indicators provides an indication of a building location from which the mobile station has placed a call. That building location can then be used as the determined mobile station location.

Claims

1. A method of locating a mobile station used for wireless communication, comprising the steps of:

determining whether at least one indicator associated with a signal used by the mobile station for a wireless communication identifies a single, known building location, the at least one indicator comprising a combination of cell codes reported by the mobile station, the combination of cell codes uniquely identifying the single, known building location, the combination of cell codes including a cell code included in a signal provided by a base station to identify at least one sector and at least one other cell code that is generated based upon the signal provided by the base station; and

determining a location of the mobile station as the known building location based on the determined indicator.

2. The method of claim 1, wherein the at least one indicator comprises at least one of

(i) a base station and sector designation that identifies a base station sector within which the mobile station was served, or

(ii) a delay of a radio frequency signal used for a communication with the mobile station.

3. The method of claim 1, comprising

establishing the at least one indicator based upon a delay of a radio frequency signal used for communication with the mobile station.

4. The method of claim 3, comprising

controlling an amount of the delay for a selected building based upon at least one of a delay associated with transmitting signals between base station sector equipment and a distributed antenna system or a delay spread associated with the distributed antenna system.

5. The method of claim 3, comprising

establishing a unique amount of delay for each of a plurality of building locations that are part of a single base station sector.

6. The method of claim 3, wherein the delay is associated with an over the air repeater used for repeating base station sector signals.

7. The method of claim 6, comprising introducing additional delay.

8. The method of claim 3, wherein the delay is associated with a fiber optic cable used for communicating signals between base station sector equipment and a distributed antenna system within a building.

9. The method of claim 8, comprising

selecting an amount of the fiber optic cable to control the amount of delay associated with signal transmissions along the fiber optic cable.

10. The method of claim 1, comprising

generating a plurality of cell codes at a repeater in a combination that uniquely identifies a selected building location;

and

associating the generated cell codes with a signal provided to the mobile station from the repeater.

11. The method of claim 1, wherein the generated cell codes comprise at least one of a PN offset or a scrambling code.

12. The method of claim 1, wherein the signal provided by the base station comprises a pilot signal and comprising

generating a plurality of cell codes by demodulating the pilot signal;

delaying the demodulated signal by a plurality of distinct amounts; and

adding the demodulated signal and the delayed signals to thereby generate multiple PN offsets, each of the PN offsets being included in the combination of cell codes reported by the mobile station.

13. The method of claim 1, wherein the signal provided by the base station comprises a pilot signal and the method includes

receiving the pilot signal from the base station at a repeater;

demodulating the pilot signal at the repeater;

delaying the demodulated pilot signal by a plurality of different amounts;

adding a result of each of the delays to the demodulated pilot signal to thereby produce a signal with a plurality of PN offsets, each of the PN offsets being included as the at least one other cell code.

14. The method of claim 13, comprising

selecting a size of each of a plurality of memory taps such that each memory tap will introduce a unique delay to the demodulated pilot signal to thereby produce a unique PN offset.

15. The method of claim 13, comprising

configuring a plurality of repeaters each with a unique combination of delays for delaying the demodulated pilot signal in a manner that each of the repeaters generates a unique combination of PN offsets.