Granted Patent B2

US 7,218,939 · App. 10/727,113 · Granted May 15, 2007

Abstract

Claims (21)

1. A method comprising:

estimating a delay of a signal received at a mobile station from a specific network element of a network within a search window; and

determining said search window based on location information available for said specific network element and based on a known distance of said mobile station to at least one other network element,

wherein said at least one other network element comprises at least two network elements, to which a respective distance was already determined based on delay measurements on signals from said at least two network elements,

wherein said search window is selected such that it covers intersection points of all circles around said at least two network elements with a radius of the respectively determined distance, and

wherein said search window is used to determine the location of said mobile station.

2. A method according to claim 1 , wherein said search window is subdivided into at least two sub-windows, each covering a respective intersection point.

3. A method according to claim 1 , wherein a respective search window is determined for at least two specific network elements in the order of their distance to said mobile station, beginning with the network element which is the closest to said mobile station.

4. A method according to claim 1 , wherein a search window is determined for at least two specific network elements in the order of the signal strength at said mobile station of signals transmitted by said network elements, beginning with the network element providing the strongest signal.

5. A method according to claim 1 , wherein the covering range of said specific network element is taken into account in addition for limiting said search window.

6. A method according to claim 1 , further comprising determining a threshold value based on the size of a determined search window, which threshold value defines the minimum signal strength of signals received at said mobile station for which a delay is estimated.

7. A method according to claim 1 , wherein said at least one other network element comprises a serving network element serving a server cell in which said mobile station is currently located.

8. Apparatus comprising:

means for receiving signals from a plurality of network elements of a network for determining the location of said mobile station and for receiving an indication of a size of a separate search window for each of said network elements; and

means for determining a delay of the received signals for each of said network elements using a respective search window having said indicated size, wherein the indication of the size of said search window increases an acquisition probability for said received signals,

wherein said search window is subdivided into at least two sub-windows, each covering a respective intersection point.

9. Apparatus comprising:

a receiver configured to receive signals from a plurality of network elements of a network for determining the location of said mobile station and for receiving an indication of a size of a separate search window for each of said network elements; and

a processor configured to determine a delay of the received signals for each of said network elements using a respective search window having said indicated size,

wherein the indication of the size of said search window increases an acquisition probability for said received signals, and

wherein said search window is subdivided into at least two sub-windows, each covering a respective intersection point.

Assignments (8)