Adaptive Polygon Computation in Adaptive Enhanced Cell Identity Positioning

• US 20100087198A1
• Filed: 03/27/2007
• Published: 04/08/2010
• Est. Priority Date: 03/27/2007
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Wigren, Torbjorn
• Granted Patent: US 8,494,550 B2
• Time in Patent Office: Days
• US Class Current: 455/446
• CPC Class Codes: G01S 5/02525 Gathering the radio frequency fingerprints
• CPC Class Codes: H04W 16/18 Network planning tools
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A method for provision of position determination assisting data in a cellular communication network comprises establishing (204) of a cell relation configuration for a user equipment. The cell relation configuration comprises cell identities of cells, in which signals fulfil a specific radio condition criterion when received. The method further comprises performing (206) of a high-precision position determination for the user equipment. The establishing and performing steps (204, 206) are repeated a plurality of times. Positioning points belonging to the same cell relation configuration are clustered (208) and a polygon is associated (212) with each result cluster. The association (212) comprises encompassing of a result cluster by a polygon, altering of the polygon corners along defined paths to improve a predetermined criterion, and counteracting that polygon corners are gathering at a minor portion of a circumference. The method finally comprises creating (212) of position determination assisting data comprising a relation between the cell relation configurations and the polygon.

Claims

1-26. -26. (canceled)

27. A method for providing position determination assisting data in a cellular communications network, comprising the steps of:

establishing a cell relation configuration for a user equipment, said cell relation configuration comprising at least cell identities of cells, in which signals to or from said user equipment fulfill at least a specific radio condition criterion when received;

performing a high-precision position determination for said user equipment;

repeating said establishing and performing steps a plurality of times;

clustering points being results of said high-precision position determinations belonging to the same cell relation configuration in separate result clusters;

associating a polygon with at least one of said result clusters, said associating step in turn comprises the steps of;

encompassing a first result cluster of said result clusters by a polygon;

altering the position of corners of said polygon along defined paths being curves through the original corner position and a single point to improve a predetermined criterion while maintaining at least a predetermined percentage of said results of high-precision position determinations of said first result cluster within the polygon; and

counteracting corners of said polygon from gathering at a minor portion of a circumference of said polygon;

creating position determination assisting data comprising a relation between said cell relation configurations and said polygon.

28. The method according to claim 27, wherein said single point is a center of gravity for said results of high-precision position determinations of said first result cluster within the polygon and wherein said step of counteracting comprises at least one reinitiation of a polygon encompassing results of high-precision position determinations of said first result cluster.

29. The method according to claim 28, wherein said reinitiated polygon is a polygon having corners distributed evenly along a circumference of the previous polygon and said step of counteracting further comprises recalculation of which points in the original cluster are situated within said reinitiated polygon.

30. The method according to claim 28, wherein said reinitiated polygon is a polygon having corners distributed evenly along a circumference of said reinitiated polygon and encompassing remaining results of high-precision position determinations of said first result cluster.

31. The method according to claim 30, wherein said corners of said reinitiated polygon are situated on an ellipse.

32. The method according to claim 28, wherein said re-initiation is performed intermittently.

33. The method according to claim 32, wherein said re-initiation is performed after a predetermined number of iterations of said altering step.

34. The method according to claim 32, wherein said re-initiation is performed when a measure of uneven corner distribution exceeds a predetermined threshold value.

35. The method according to claim 34, wherein said measure of uneven corner distribution is:

$\mathrm{\sigma <br><br>}=\frac{\underset{i}{\max <br><br><br><br>d_i^p}}{\underset{i}{\min }<br><br>d_i^p}$

where d_i^p are distances between adjacent corners.

36. The method according to claim 27, wherein said step of counteracting comprises selecting said single point as a point outside said polygon encompassing said first result cluster.

37. The method according to claim 36, wherein said polygon encompassing said first result cluster is a polygon having points located at two ellipsoid arc sections centered at said single point.

38. The method according to claim 27, wherein said defined path is a curve through the original corner position and a first point within said first result cluster, and wherein said step of counteracting comprises selecting a closest point of a plurality of points within said first result cluster as said first point for each polygon corner.

39. The method according to claim 27, wherein said step of counteracting comprises selection of said defined path as a curve asymptotically closing up to a path being equidistant to the two closest neighboring corners.

40. The method according to claim 27, wherein said step of counteracting comprised deletion of at least one polygon corner among polygon corners gathering at a minor portion of a circumference of said polygon.

41. The method according to claim 40, wherein said deletion is performed when a measure of uneven corner distribution exceeds a predetermined threshold value.

42. The method according to claim 41, wherein said measure of uneven corner distribution is:

$\mathrm{\sigma <br><br>}=\frac{\underset{i}{\max <br><br><br><br>d_i^p}}{\underset{i}{\min }<br><br>d_i^p}$

where d_i^p are distances between adjacent corners.

43. The method according to claim 27, wherein an area measure of said associated polygon is minimized during said step of altering.

44. The method according to claim 27, wherein said altering step comprises altering of one corner position at a time, allowing one of said high-precision position determinations of said result cluster to be placed outside said polygon, but not two of said high-precision position determinations.

45. The method according to claim 27, wherein said clustering, associating and creating steps are performed continuously or intermittently.

46. A method for radio network planning, comprising the steps of:

obtaining position determination assisting data according to claim 27, wherein said step of performing a high-precision position determination is performed on demand; and

evaluating said position determination assisting data regarding actual radio propagation.

47. A method for determining a position of a user equipment in a cellular communications network, comprising the steps of:

obtaining position determination assisting data according to claim 27;

establishing a cell relation configuration for said user equipment;

said cell relation configuration comprising at least cell identities of cells, in which signals to or from said user equipment fulfill at least a specific radio condition criterion when received; and

determining, by said position determination assisting data, a polygon related to said cell relation configuration as defining an area in which said user equipment is positioned.

48. An arrangement for providing position determination assisting data in a cellular communications network, comprising:

a cell relation configuration determining circuit for establishing a cell relation configuration for a user equipment;

said cell relation configuration comprising at least cell identities of cells, in which signals to or from said user equipment fulfill at least a specific radio condition criterion when received;

a high-precision position determining circuit for performing a high-precision position determination for said user equipment;

a clustering circuit for clustering points being results of a plurality of said high-precision position determinations belonging to the same cell relation configuration in separate result clusters; and

a computing circuit for associating a polygon with at least one of said result clusters, said computing circuit being arranged for;

encompassing a first result cluster of said result clusters by a polygon;

altering the position of corners of said polygon along defined paths being curves through the original corner position and a single point to improve a predetermined criterion while maintaining at least a predetermined percentage of said results of high-precision position determinations of said first result cluster within the polygon; and

counteracting corners of said polygon from gathering at a minor portion of a circumference of said polygon; and

an assisting data determining circuit for creating position determination assisting data comprising a relation between said cell relation configurations and said associated polygons.

49. The arrangement of claim 48, further comprising a position determining arrangement configured to determine a position of the user equipment based on the position determination assisting data, said position determining arrangement comprising a control circuit that is configured to determine, by said position determination assisting data, a polygon related to said cell relation configuration as defining an area in which said user equipment is positioned.

50. A node of a cellular communications network, comprising the arrangement of claim 48.

51. The node according to claim 50, wherein the node comprises one of:

a base station;

a base station controller;

a radio network controller;

a service mobile location center; and

a stand-alone service mobile location center.