Enhanced cell ID location method using non uniform subsectors and neighboring cell centroid

• US 9,176,216 B2
• Filed: 03/15/2013
• Issued: 11/03/2015
• Est. Priority Date: 12/14/2012
• Status: Active Grant

• Current Assignee: TeleCommunication Systems Inc (Comtech Telecommunications Corporation)
• Original Assignee: Maple Acquisition LLC (Verso Corporation)
• Inventors: Al-Mufti, Khalid, Hannan, Ariful, Kalenahalli, Suryanarayana, Srinivasan, Navin
• Primary Examiner(s): Agosta, Steve D
• Application Number:
  US13/834,057
• Publication Number:
  US 20140171105A1
• Time in Patent Office: 963 Days
• Field of Search: 455/404.1, 455/0.2, 455/414.1, 455/456.1, 455/0.3, 455/0.4, 455/0.5, 455/0.6, 455/457, 701/207, 701/213, 701/214, 701/216, 701/400, 701/408, 701/410, 701/411, 701/445, 701/454, 701/469, 340/988, 342/367.1, 342/0.06, 342/0.12, 342/450, 342/457, 342/357.2, 342/357.23
• US Class Current: 1/1
• CPC Class Codes: G01S 5/02955 by computing a weighted average of the positions of the signal transmitters
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A system and method of determining the location of a mobile device. Network measurement report information may be received from a target mobile device, the NMR having measurement information and range information of the target mobile device from a cell serving the device. The serving cell may be divided a plurality of subsectors and candidate locations placed on an intersection of a range formed from the range information and bisectors of the plurality of subsectors. A subset of neighboring and serving cells may be selected as a function of the NMR measurement information and a radio frequency (RF) coverage centroid determined for each of the selected neighboring cells. A centroid of the determined RF centroids may be determined, and a location of the target mobile device estimated as the candidate location having a minimum distance to the determined centroid.

Claims

1. A method of determining the location of a mobile device comprising the steps of:

(a) receiving measurement information from cells neighboring the serving cell and range information from the serving cell;

(b) dividing the serving cell into a plurality of subsectors;

(c) placing candidate locations on an intersection of bisectors of the plurality of subsectors and a range determined using the range information;

(d) selecting a subset of neighboring and serving cells as a function of the measurement information;

(e) determining a radio frequency (RF) coverage centroid for each of the selected neighboring cells;

(f) determining a centroid of the determined RF centroids based on a weighted average of selected neighboring cell centroids, wherein each of the weights of the weighted average vary as a function of at least one of a neighboring cell power level, a serving cell power level and an inter-site distance between neighboring cells and serving cells;

(g) determining a location of the target mobile device as the candidate location having a minimum distance to the determined centroid.

2. The method of claim 1 wherein the measurement information is selected from the group consisting of an absolute received signal power level observed at the target mobile device, a ratio of received signal power to maximum received power, and combinations thereof.

3. The method of claim 1 wherein the step of selecting a subset of neighboring and serving cells further comprises weighting measurement information for one or more of the neighboring and serving cells as a function of cell size.

4. The method of claim 1 further comprising the step of determining radial or angular uncertainties of the mobile device location.

5. The method of claim 1 wherein one determined RF centroid is a midpoint of the RF coverage area of the serving cell.

6. The method of claim 1 wherein one determined RF centroid is a function of values selected from the group consisting of antenna pattern, transmit power of the broadcast signal from a neighboring or serving cell, and combinations thereof.

7. The method of claim 1, wherein the RF coverage centroid for each of the selected neighboring cells is spaced apart from base stations that serve the neighboring cells.

8. A method of determining the location of a mobile device comprising the steps of:

(a) receiving measurement information from cells neighboring the serving cell and range information from the serving cell;

(b) dividing the serving cell into a plurality of subsectors;

(c) placing candidate locations on an intersection of bisectors of the plurality of subsectors and a range determined using the range information;

(d) selecting a subset of neighboring and serving cells as a function of the measurement information;

(e) determining a radio frequency (RF) coverage centroid for each of the selected neighboring cells;

(f) determining a centroid of the determined RF centroids;

(g) determining a location of the target mobile device as the candidate location having a minimum distance to the determined centroid;

wherein the step of selecting a subset of neighboring and serving cells further comprises weighting measurement information for one or more of the neighboring and serving cells as a function of cell size;

wherein cell size is determined as a function of transmission power level of the respective cell, timing advance values from mobile devices within the respective cell, and combinations thereof.

9. A method of determining the location of a mobile device comprising the steps of:

(a) receiving measurement information from cells neighboring the serving cell and range information from the serving cell;

(b) dividing the serving cell into a plurality of subsectors;

(c) placing candidate locations on an intersection of bisectors of the plurality of subsectors and a range determined using the range information;

(d) selecting a subset of neighboring and serving cells as a function of the measurement information;

(e) determining a radio frequency (RF) coverage centroid for each of the selected neighboring cells;

(f) determining a centroid of the determined RF centroids;

(g) determining a location of the target mobile device as the candidate location having a minimum distance to the determined centroid;

(h) determining a radial uncertainty of the mobile device location, wherein the radial uncertainty is determined as a function of type of range information.

10. A method of determining the location of a mobile device comprising the steps of:

(a) receiving measurement information from cells neighboring the serving cell and range information from the serving cell;

(b) dividing the serving cell into a plurality of subsectors;

(c) placing candidate locations on an intersection of bisectors of the plurality of subsectors and a range determined using the range information;

(d) selecting a subset of neighboring and serving cells as a function of the measurement information;

(e) determining a radio frequency (RF) coverage centroid for each of the selected neighboring cells;

(f) determining a centroid of the determined RF centroids;

(g) determining a location of the target mobile device as the candidate location having a minimum distance to the determined centroid;

(h) determining an angular uncertainty of the mobile device location, wherein the angular uncertainty is determined as a function of the selected subsector.

11. A method of determining the location of a mobile device comprising the steps of:

(a) receiving measurement information from cells neighboring the serving cell and range information from the serving cell;

(b) dividing the serving cell into a plurality of subsectors;

(c) placing candidate locations on an intersection of bisectors of the plurality of subsectors and a range determined using the range information;

(d) selecting a subset of neighboring and serving cells as a function of the measurement information;

(e) determining a radio frequency (RF) coverage centroid for each of the selected neighboring cells;

(f) determining a centroid of the determined RF centroids;

(g) determining a location of the target mobile device as the candidate location having a minimum distance to the determined centroid;

wherein the step of determining a centroid of the determined RF centroids further comprises performing an unequally weighted average of selected neighboring cell centroids;

wherein the weights are a function of values selected from the group consisting of neighboring cell power level, serving cell power level, inter-site distance between neighboring and serving cells, and combinations thereof.