METHOD AND APPARATUS FOR DETERMINING THE LOCATION OF A NODE IN A WIRELESS SYSTEM

• US 20090197613A1
• Filed: 01/31/2008
• Published: 08/06/2009
• Est. Priority Date: 01/31/2008
• Status: Abandoned Application

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Song, Goushu, Zhang, Chuntao, Babin, Thomas S., Wu, Xiaohua, Wang, Yinyan
• Application Number:
  US12/023,220
• Publication Number:
  US 20090197613A1
• Time in Patent Office: Days
• US Class Current: 455/456.1
• CPC Class Codes: H04W 8/30 Network data restoration; Network data reliability; Network data fault tolerance

Abstract

A method and apparatus for determining the location of a node within a wireless communication system is provided herein. In order to determine the location of a node, a series of GSM network measurement reports (NMRs) received at multiple base stations are analyzed by location-finding equipment. Multiple reports from the same mobile unit are analyzed for their received signal strength and multiple location estimates are then determined for the node. The location estimates are then averaged and weighted to determine an accurate location estimate for the node.

Claims

1. A method for determining a location of a node, the method comprising the steps of:

receiving a plurality of GSM network measurement reports;

determining a call group from those network measurement reports having a same identification;

determining signal-strength measurements from the plurality of GSM network measurement reports within the call group; and

determining a location from the signal-strength measurements.

2. The method of claim 1 wherein the location comprises an (x,y) location.

3. The method of claim 2 further comprising the step of:

averaging a plurality of locations to produce an average location.

4. The method of claim 3 wherein the step of averaging the plurality of locations to produce the average location comprises the step of calculating ( x, y) as:

5. The method of claim 4 further comprising the step of:

calculating ({circumflex over (x)}_i,ŷ

_i) based on weighting the ( x, y) location.

6. The method of claim 5 wherein the step of calculating ({circumflex over (x)}_i,ŷ

_i) comprises the step of calculating;

{circumflex over (x)}_i=w x+(1−

w)x_i and ŷ

_i=w y+(1−

w)y_i, where

w=exp(−

n²/c)

where n=N/N_max and the parameter c>

0 and controls a rate of fall-off of w having a call-group size of N.

7. An apparatus for determining a location of a node, the apparatus comprising:

a receiver receiving a plurality of GSM network measurement reports;

logic circuitry determining a call group from those measurement reports having a same identification, determining signal-strength measurements from the plurality of GSM network measurement reports within the call group, and determining a location from the signal-strength measurements.

8. The apparatus of claim 7 wherein the location comprises an (x,y) location.

9. The apparatus of claim 8 wherein the logic circuitry additionally averages a plurality of locations to produce an average location.

10. The apparatus of claim 9 wherein the logic circuitry calculates the averages by calculating ( x, y) as:

11. The apparatus of claim 10 wherein the logic circuitry calculates ({circumflex over (x)}_i,ŷ

_i) based on weighting the ( x, y) location.

12. The apparatus of claim 11 wherein calculating ({circumflex over (x)}_i,ŷ

_i) comprises calculating

{circumflex over (x)}_i=w x+(1−

w)x_i and ŷ

_i=w y+(1−

w)y_i, where

w=exp(−

n²/c)

where n=N/N_max and the parameter c>

0 and controls a rate of fall-off of w having a call-group size of N.