Method and apparatus for determining the location of a node in a wireless system

• US 7,436,781 B2
• Filed: 06/02/2005
• Issued: 10/14/2008
• Est. Priority Date: 06/02/2005
• Status: Active Grant

• Current Assignee: Ruckus IP Holdings LLC
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Shi, Qicai, Kyperountas, Spyros, Huang, Jian, Niu, Feng
• Primary Examiner(s): Ho, Duc C
• Application Number:
  US11/143,253
• Publication Number:
  US 20060274676A1
• Time in Patent Office: 1,230 Days
• Field of Search: 370/255, 370/328, 370/332, 370/338, 370/396, 370/400, 342/451, 342/458, 455/456.1, 455/456.5, 455/456.6, 455/513
• US Class Current: 370/252
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks
• CPC Class Codes: H04B 17/27 for locating or positioning the transmitter

Abstract

A method and apparatus for determining the path loss model of an object within a wireless communication system is provided herein. During operation, a path loss model for a node is generated based on path loss values and corresponding numbers of neighbors of the said node. The path loss model is used to determine a relationship between path loss and distance. With this relationship established, distances to known-located nodes may be obtained by obtaining a path loss to the known-located node. From these distances, a node can then be located.

Claims

1. A method for locating a node within a wireless communication system, the method comprising the steps of:

determining a plurality of path loss values to a plurality of nodes;

determining a path loss model that is a function of node density and the path loss to the plurality of nodes, wherein the node density comprises a value of nodes per unit area or volume;

determining distances to known located nodes based on the path loss model; and

locating the node based on distances to known located nodes.

2. The method of claim 1 wherein the step of determining the path loss model comprises the step of determining a relationship between path loss and distance.

3. The method of claim 1 wherein the step of determining the path loss model based on the node density comprises the step of determining the path loss model based on a number of nodes per square meter.

4. The method of claim 1 wherein the step of determining the path loss model based on the node density comprises the step of determining the path loss model based on a number of nodes per cubic meter.

5. The method of claim 1 wherein the step of determining the path loss comprises the step of determining a difference between a power a signal was received at and a power the signal was transmitted at.

6. The method of claim 1 wherein the step of determining the plurality of neighboring nodes comprises the step of determining the plurality of neighboring nodes form a neighbor list.

7. The method of claim 1 wherein the path loss model is not based on distance to other nodes.

8. A method comprising the steps of:

determining a plurality of neighboring nodes;

determining number of neighboring nodes having a path loss less than a particular neighboring node;

determining a path loss model based on a node density and the number of nodes having the path loss less than the particular node, wherein the node density comprises a value of nodes per unit area or volume;

determining distances to known-located nodes based on the path loss model; and

determining a location based on the distances to known-located nodes.

9. The method of claim 8 wherein the step of determining the path loss model comprises the step of determining a relationship between path loss and distance.

10. The method of claim 8 wherein the step of determining the path loss model based on the node density comprises the step of determining the path loss model based on a number of nodes per square meter.

11. The method of claim 8 wherein the step of determining the path loss model based on the node density comprises the step of determining the path loss model based on a number of nodes per cubic meter.

12. An apparatus comprising:

a receiver receiving signals from a plurality of nodes; and

logic circuitry analyzing the signals from the plurality of nodes to determine a number of nodes having a path loss less than a particular node, determine a path loss model based on a node density and a number of nodes having the path loss less than the particular node, determine distances to known-located nodes based on the path loss model, and determine a location based on the distances to known-located nodes, wherein the node density comprises a value of nodes per unit area or volume.

13. The apparatus of claim 12 wherein the path loss model comprises a relationship between path loss and distance.

14. The apparatus of claim 12 the node density comprises a number of nodes per square meter.

15. The apparatus of claim 12 wherein the node density comprises a number of nodes per cubic meter.

16. The apparatus of claim 12 wherein the path loss comprises a difference between a power a signal was received at and a power the signal was transmitted at.