US 8,576,818 B2Granted

Location of mobile network nodes

AssigneeDigi International Inc.

InventorsPaul A. Dahl, Scott McCall

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Abstract

The physical position of an unknown node in a network is determined by sending a first sent WiFi signal from one of an unknown node and a first reference node having a known location, and repeating the sent WiFi signal in the other of the unknown node and first reference node with a first reply WiFi signal. A distance is derived between the unknown node and the first reference node from the time of flight of the first sent and first reply WiFi signals. A second WiFi signal is sent from one of the unknown node and a second fixed node having a known location, and repeating the sent second WiFi signal in the other of the unknown node and second reference node with a second reply WiFi signal, and A distance is derived between the unknown node and the second reference node from the time of flight of the second sent and second reply WiFi signals. A physical location of the unknown node is determined based on the derived distances between the unknown node and the first and second reference nodes.

Claims10

Dependent claims

A method of determining the physical position of a movable node in a network, comprising:

sending a first sent WiFi signal from one of an unknown node and a first reference node having a known location, and repeating the sent WiFi signal in the other of the unknown node and first reference node with a first reply WiFi signal;
deriving a distance between the unknown node and the first reference node from the time of flight of the first sent and first reply WiFi signals;
sending a second sent WiFi signal from one of the unknown node and a second fixed node having a known location, and repeating the sent second WiFi signal in the other of the unknown node and second reference node with a second reply WiFi signal;
deriving a distance between the unknown node and the second reference node from the time of flight of the second sent and second reply WiFi signals;
and
determining a physical location of the unknown node based on the derived distances between the unknown node and the first and second reference nodes;
wherein repeating at least one of the first and second sent WiFi signals comprises repeating the respective sent WiFi signal with the respective first or second reply WiFi signal on a different frequency or channel than the respective sent WiFi signal without processing the respective sent WiFi signal.

4 more elements

A wireless network, comprising:

an unknown node having an unknown physical position;
a first reference node, wherein one of the unknown node and the first reference node is operable to send a first sent signal, and the other of the unknown node and first reference node is operable to repeat the first sent signal by sending a first reply signal;
and
a second reference node, wherein one of the unknown node and the second reference node is operable to send a second sent signal, and the other of the unknown node and second reference node is operable to repeat the second sent signal by sending a second reply signal;
at least one node in the wireless network further operable to derive a distance between the unknown node and the first reference node from the time of flight of the first sent and first reply signals, derive a distance between the unknown node and the second reference node from the time of flight of the second sent and second reply signals, and determine a physical location of the unknown node based on the derived distances between the unknown node and the first and second reference nodes;
wherein repeating at least one of the first and second sent signals comprises repeating the respective sent signal with the respective first or second reply signal on a different frequency or channel than the respective sent signal without processing the respective sent signal.

3 more elements

Dependencies are inferred from the claim text.