| US 7,558,583 B2 | ||
| System and methods of radio interference based localization in sensor networks | ||
| Akos Ledeczi, Nashville, Tenn. (US); Miklos Maroti, Szeged (Hungary); Peter Volgyesi, Balatonszarszo (Hungary); Andras Nadas, Kecskemet (Hungary); Karoly Molnar, Budapest (Hungary); Sebestyen Dora, Szekesfehervar (Hungary); Branislav Kusy, Banovce nad Bebravou (Slovakia (Slovak Republic)); and Gyorgy Balogh, Váchartyán (Hungary) | ||
| Assigned to Vanderbilt University, Nashville, Tenn. (US) | ||
| Filed on Apr. 10, 2006, as Appl. No. 11/401,115. | ||
| Claims priority of provisional application 60/669652, filed on Apr. 08, 2005. | ||
| Prior Publication US 2007/0042706 A1, Feb. 22, 2007 | ||
| Int. Cl. H04W 24/00 (2009.01) | ||
| U.S. Cl. 455—456.1 [455/1; 455/73; 455/39; 455/418; 455/404.2; 455/414.2; 455/9; 455/115.1; 455/115.2] | 26 Claims |
| 1. A method for radio interference based sensor localization in a wireless sensor network, wherein the wireless sensor network
has a plurality of spatially separated sensor nodes with each capable of transmitting and/or receiving a signal, comprising
the steps of:
a. selecting a first sensor node and a second sensor node as a pair of transmitters and each of the remaining sensor nodes
as a receiver in the wireless sensor network, respectively;
b. transmitting a first signal and a second signal from the selected first sensor node and the selected second sensor node,
respectively, to the wireless sensor network, wherein the first signal has a frequency, f1, and the second signal has a frequency, f2, the frequencies f1 and f2 being substantially close to each other such that a superposition of the first signal and the second signal in a position
of space where a receiver is located results in an interference signal;
c. using the interference signal received by each of the receivers to estimate a phase offset of the received interference
signal at the corresponding receiver, respectively;
d. obtaining a difference of the phase offsets of the interference signal for a pair of receivers;
e. calculating a distance range between the pair of transmitters and the corresponding pair of receivers from the obtained
difference of phase offsets of the interference signal for the pair of receivers;
f. repeating steps (d) and (e) for the remaining receivers to obtain a set of the distance ranges; and
g. localizing relative positions of the plurality of spatially separated sensor nodes in the wireless sensor network from
the set of the distance ranges,
wherein the method further comprises the step of performing a frequency tuninci algorithm to determine a radio frequency setting
for the pair of transmitters to transmit the first and second signals with a frequency difference substantially close to zero,
and wherein performing the frequency tuning algorithm comprises the steps of:
(i) transmitting a first signal at a frequency varied at a fine-grain step and a second signal at a fixed frequency from a
first and second transmitters of the pair of transmitters, respectively;
(ii) analyzing a frequency of the interference signal received by a receiver to determine the frequency of the first signal
for which the frequency of the interference signal substantially close to zero, wherein the frequency of the interference
signal is coincident with the frequency difference of the first signal and the second signal; and
(iii) propagating information of the analyzed frequency back to the first transmitter by the receiver, thereby causing the
first transmitter to determine the radio frequency setting of the pair of transmitters for which the frequency of the interference
signal is within a predetermined range.
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