Cooperation Utility in Sensing

Yu-Ching Tong
Advisor: Greg Pottie

Monday, November 2, 2009 at 1:30pm-2:30pm
Engr IV Room 67-124

Abstract:
We present arguments that a small number of sensors within the network provide most of the utility. That is, cooperation of more than a small number of nodes has little benefit. We present two scenarios. In the first scenario, all sensors provide identical utility, and their utilities are aggregated sequentially. The second scenario is sensor fusion with signal strength decreasing with distance. In that scenario the source is at the origin and the sensors are distributed, either uniformly or according to a planar standard normal distribution. We also vary the total number of sensors distributed in both scenarios to observe the utility/density trade off. Localization using the Fisher Information as the utility metric is used to demonstrate that few sensors are sufficient to derive most of the utility out of the sensor network. Simulation results back up an order statistics analysis of the behavior.

The implication is that while co-operation is useful for some objectives such as combating fading and uncertainty of individual sensors, it is inefficient as a mean to increase the utility of a sensor network if the best sensor's utility is significantly short of the desired utility. In addition, asymptotic results under fixed density are presented. In this situation, the utility improvement is logarithmic at best as the number of sensors and the distance to the sensors increase. Coverage area as utility metric is considered in a lattice deployment and a random deployment scenario. In both cases small neighborhood of cooperation provide noticeable performance improvement. In reconstruction problem the effectiveness of global versus local cooperation depends heavily on the model relating the measurement and the source. When the model describes the relationship accurately, reconstruction, regardless of cooperation size, will work well. This problem illustrate the model has a larger impact then cooperation size.

Biography:
Yu-Ching Tong was born in Hong Kong, in 1979. He received the B.S. and M.S. degrees in Electrical Engineering from University of California, Los Angeles, in 2001 and 2002. He was a Payload System Engineer at Boeing Satellite System between 2001 and 2007. His research interests include communications and signal processing.