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International Journal of Distributed Sensor Networks
Volume 2011 (2011), Article ID 980953, 17 pages
http://dx.doi.org/10.1155/2011/980953
Research Article

Low-Complexity, Distributed Characterization of Interferers in Wireless Networks

1Network Systems Engineering, AT&T Labs, 2600 Camino Ramon, CA 94583, USA
2Robert Bosch LLC, Research and Technology Center North America, 4009 Miranda Avenue, Palo Alto, CA 94304, USA
3School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Drive NW, Atlanta, GA 30332-0250, USA

Received 8 February 2011; Revised 21 May 2011; Accepted 25 May 2011

Copyright © 2011 Vibhav Kapnadak et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We consider a large-scale wireless network that uses sensors along its edge to estimate the characteristics of interference from neighboring networks or devices. Each sensor makes a noisy measurement of the received signal strength (RSS) from an interferer, compares its measurement to a threshold, and then transmits the resulting bit to a cluster head (CH) over a noisy communication channel. The CH computes the maximum likelihood estimate (MLE) of the distance to the interferer using these noise-corrupted bits. We propose and justify a low-complexity threshold design technique in which the sensors use nonidentical thresholds to generate their bits. This produces a dithering effect that provides better performance than previous techniques that use different non-identical thresholds or the case in which all the sensor motes use an identical non-optimal threshold. Our proposed technique is also shown (a) to be of low complexity compared to previous non-identical threshold approaches and (b) to provide performance that is very close to that obtained when all sensors use the identical, but unknown, optimal threshold. We derive the Cramér-Rao bound (CRB) and also show that the MLE using our dithered thresholds is asymptotically both efficient and consistent. Simulations are used to verify these theoretical results.