Method for estimating the location of a wireless device in a communication network

• US 20060281470A1
• Filed: 06/08/2005
• Published: 12/14/2006
• Est. Priority Date: 06/08/2005
• Status: Active Grant

• Current Assignee: ARRIS Enterprises LLC (CommScope Holding Company, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Huang, Jian, Shi, Qicai, Kyperountas, Spyros, Correal, Neiyer S.
• Granted Patent: US 7,353,031 B2
• Time in Patent Office: Days
• US Class Current: 455/456.200
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks

Abstract

A method for estimating the location of a blindfolded node (235) in a wireless network having reference nodes (225, 230) is provided. The reference nodes (225, 230) are combined into pairs (301) and each pair is checked to determine if the reference nodes are within each other'"'"'s communication rage (304). A plurality of probable regions (315) for the blindfolded node are obtained (313, 315). These probable regions are overlapped (320), and the blindfolded node'"'"'s estimated location is estimated to be the geometric center of the overlapped regions (325).

Claims

1. A method of estimating a location of a blindfolded node in a wireless network having a plurality of reference nodes, the method comprising:

combining the plurality of reference nodes into reference pairs;

obtaining a plurality of probable regions for the blindfolded node based on the reference pairs;

overlapping the plurality of probable regions; and

estimating the location of the blindfolded node as a geometric center of the overlapped plurality of probable regions.

2. The method of claim 1, wherein the step of obtaining a plurality of probable regions for the blindfolded node based on the reference pairs, includes the steps of:

determining whether each reference pair'"'"'s reference nodes are not within communication range of each other; and

for each reference pair'"'"'s reference nodes that are not within communication range of each other, determining a common region between a first geometric region and a second geometric region, the first geometric region being determined by a geometric location of a first reference node and a maximum communication range of the first reference node, and the second geometric region being determined by a geometric location of the second reference node and a maximum communication range of the second reference node, the probable location of the blindfolded node being within the common region.

3. The methods of claim 2 wherein the geometric region is a circular region.

4. The method of claim 1, wherein the step of obtaining a plurality of probable regions for the blindfolded node based on the reference pairs, includes the steps of:

determining whether first and second reference nodes of the reference pair are within each other'"'"'s communication range; and

when the first and second reference nodes are within each other'"'"'s communication range, calculating proximity information between the blindfolded node and the first and second reference nodes to obtain first, second and third proximities; and

comparing the first proximity with the third proximity and the second proximity with the third proximity for each pair of reference nodes to obtain the plurality of probable regions.

5. The method of claim 4, wherein the step of calculating comprises:

calculating the first proximity between the blindfolded node and the first reference node based on a predetermined parameter;

calculating the second proximity between the blindfolded node and the second reference node based on the predetermined parameter; and

calculating a third proximity between the first reference node and the second reference node based on the predetermined parameter, the first reference node and the second reference node being within a communication range of each other.

6. The method of claim 5, wherein the predetermined parameter comprises at least one of received signal strength indicator, a magnetic strength indicator, an infrared strength indicator and a time of arrival indicator.

7. The method of claim 1, further comprising determining the location of another blindfolded node by using the estimated location of a current blindfolded node as a reference node in conjunction with the plurality of reference nodes.

8. The method of claim 1, wherein the step of overlapping further includes the step of expanding a probable region when there no overlapping area so as to create an overlapping area.

9. A method of determining a location of a blindfolded node using a plurality of reference nodes in a wireless network, the method comprising:

determining a plurality of reference node proximities for each reference node, the plurality of reference node proximities comprising a proximity of the reference node to each other reference node in the plurality of reference nodes based on a predetermined parameter;

determining a blindfolded node proximity between each reference node and the blindfolded node based on the predetermined parameter;

performing a comparison between the blindfolded node proximity and the plurality of reference nodes for each reference node to obtain a plurality of probable locations of the blindfolded node; and

identifying the location of the blindfolded node using the plurality of probable locations.

10. The method of claim 9, wherein the step of performing a comparison comprises:

determining the probable location of the blindfolded node to be within a geometric region when the blindfolded node proximity is greater than a maximum value of the plurality of proximities, the geometric region being determined by the location of the reference node and the distance between the reference node and a maximum value reference node, the maximum value reference node corresponding to the maximum proximity value.

11. The method of claim 9, wherein the step of performing a comparison comprises:

determining the probable location of the blindfolded node to be within a ring region when the blindfolded node proximity is between first value and a second value of the plurality of proximities, the ring region being a region between a first geometric region and a second geometric region, the first geometric region being determined by the location of the reference node and distance between the reference node and the reference node corresponding to the first value and the second geometric region being determined by the location of the reference node and the distance between the reference node and the reference node corresponding to the second value.

12. The method of claim 9, wherein the step of performing a comparison comprises:

determining the probable location of the blindfolded node to be a ring region when the blindfolded node proximity is less than the minimum value of the plurality of proximities, the ring region being a region between a first geometric region and a second geometric region, the first geometric region being determined by the location of the reference node and the distance between the reference node and a minimum value reference node, the minimum value reference node corresponding to the minimum proximity value and the second geometric region being determined by the location of reference node and a maximum communication range of the reference node.

13. The method of claim 9, wherein the plurality of reference node proximities is sorted before performing the comparison.

14. The method of claim 9, wherein the identifying step further comprises:

computing an overlapping area of the plurality of probable regions; and

determining a geometric center of the overlapping area.

15. The method of claim 9 further comprising:

determining the location of a blindfolded node by using the located blindfolded node within the communication range of the blindfolded node as a reference node along with all the reference nodes within the communication range of the blindfolded node.

16. The method of claim 9, wherein the predetermined parameter comprises at least one of received signal strength indicator, a magnetic strength indicator, an infrared strength indicator and a time of arrival indicator.

17. The method of claim 14, wherein the step of computing the overlapping area comprises expanding the probable regions when there no overlapping area so as to create an overlapping area.

18. A method of locating a blindfolded node in a wireless network, the method comprising:

providing a single reference node within the wireless network; and

determining a probable location of the blindfolded node to be within a geometric region, the geometric region being determined by the location of the single reference node and the maximum communication range of the single reference node.

19. The method of claim 18, wherein the geometric region is a circular region being centered by the location of the single reference node and with a radius substantially equal to the maximum communication range of the single reference node.

20. The method of claim 18 further comprising:

promoting the located blindfolded node within the communication range of the blindfolded node as reference nodes; and

re-determining the location of the blindfolded node with all the promoted reference nodes and the reference node.