DETERMINING NODE LOCATION IN A WIRELESS NETWORK

• US 20110249594A1
• Filed: 04/13/2010
• Published: 10/13/2011
• Est. Priority Date: 04/13/2010
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Florentino, Marco, Wu, Wei, Williams, R. Stanley
• Granted Patent: US 8,493,890 B2
• Time in Patent Office: Days
• US Class Current: 370/255
• CPC Class Codes: G01S 5/06 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/12 takes precedence

Abstract

Transmitting nodes broadcast chirped signals on a wireless network. The transmitting nodes are time-synchronized with each other and location of the transmitting nodes is known. A receiver node detects beat frequencies created by pairs of chirped signals from different pairs of transmitting nodes. Time delay differences between chirped signals in respective beat frequency pairs are determined. The receiver node'"'"'s location is determined in view of the time delay differences.

Claims

1. A method for determining node location in a wireless network, comprising:

receiving, at a receiver node, chirped signals broadcast from transmitting nodes in the wireless network, wherein the transmitting nodes are time-synchronized with each other and location of the transmitting nodes is known;

detecting beat frequencies created by pairs of chirped signals from different pairs of transmitting nodes;

determining time delay differences between chirped signals in respective beat frequency pairs; and

determining a location of the receiver node in view of the time delay differences.

2. The method of claim 1, wherein the transmitting nodes are base stations having known locations and wherein the base stations are time-synchronized via Global Position System (GPS).

3. The method of claim 1, wherein the chirped signals are linearly chirped.

4. The method of claim 1, further comprising:

collecting sensory data at the receiver node; and

tagging the sensory data with the determined location information.

5. The method of claim 4, further comprising:

combining tagged sensory data from the receiver node with tagged sensory data from other receiver nodes in the network to generate a map of sensory data for the network.

6. The method of claim 1, wherein broadcasting chirped signals from transmitting nodes comprises:

assigning two transmitting nodes a common timeslot;

broadcasting a first chirped signal from one of the transmitting nodes at the common timeslot; and

broadcasting a second chirped signal from the other transmitting node at the common timeslot, wherein the first and second chirped signals are identical.

7. The method of claim 1, wherein determining the location comprises:

triangulating the location in view of the time delay differences.

8. An apparatus, comprising:

a receiver node to receive chirped signals from a plurality of time-synchronized base stations, the chirped signals broadcast at assigned timeslots;

a measurement module to measure a beat frequency created by received chirped signals from a pair of base stations; and

a processing unit to determine a location of the receiver node based at least in part on beat frequency measurements for different base stations pairs.

9. The apparatus of claim 8, wherein each base station comprises:

a GPS chip to synchronize a base station clock with other base station clocks and to provide location information for the base station.

10. The system of claim 8, wherein the receiver node further comprises a sensor to collect external sensory information and wherein the system further comprises:

a tagging module to tag external sensory information with location information determined by the processing unit.

11. The system of claim 8, further comprising:

a timeslot management module to coordinate sharing of a timeslot by at least two base stations.

12. A computer-readable storage medium containing instructions, that when executed, cause a computer to:

detect beat frequencies created by chirped signals from different base stations;

determine time delay differences between the chirped signals based at least in part on the beat frequencies; and

determine a relative location of a receiver node with respect to the base stations via triangulation in view of the time delay differences.

13. The computer-readable storage medium of claim 12, comprising further instructions that cause the computer to:

collect sensory data at the receiver node; and

tag the sensory data with location information determined via the triangulation.

14. The computer-readable storage medium of claim 12, comprising further instructions that cause the computer to:

combine tagged sensory data from the receiver node with tagged sensory data from other receiver nodes in the network; and

generate a map of sensory data for the network.