Distributed Detection and Fusion in a Large Wireless Sensor Network of Random Size
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Distributed Detection and Fusion in a Large Wireless Sensor Network of Random Size Ruixin Niu Department of Electrical Engineering and Computer Science, Syracuse University, 335 Link Hall, Syracuse, NY 13244-1240, USA Email: [email protected]
Pramod K. Varshney Department of Electrical Engineering and Computer Science, Syracuse University, 335 Link Hall, Syracuse, NY 13244-1240, USA Email: [email protected] Received 11 December 2004; Revised 9 May 2005 For a wireless sensor network (WSN) with a random number of sensors, we propose a decision fusion rule that uses the total number of detections reported by local sensors as a statistic for hypothesis testing. We assume that the signal power attenuates as a function of the distance from the target, the number of sensors follows a Poisson distribution, and the locations of sensors follow a uniform distribution within the region of interest (ROI). Both analytical and simulation results for system-level detection performance are provided. This fusion rule can achieve a very good system-level detection performance even at very low signalto-noise ratio (SNR), as long as the average number of sensors is sufficiently large. For all the different system parameters we have explored, the proposed fusion rule is equivalent to the optimal fusion rule, which requires much more prior information. The problem of designing an optimum local sensor-level threshold is investigated. For various system parameters, the optimal thresholds are found numerically by maximizing the deflection coefficient. Guidelines on selecting the optimal local sensor-level threshold are also provided. Keywords and phrases: wireless sensor networks, distributed detection, decision fusion, deflection coefficient.
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INTRODUCTION
Recently, wireless sensor networks (WSNs) have attracted much attention and interest, and have become a very active research area. Due to their high flexibility, enhanced surveillance coverage, robustness, mobility, and cost effectiveness, WSNs have wide applications and high potential in military surveillance, security, monitoring of traffic, and environment. Usually, a WSN consists of a large number of lowcost and low-power sensors, which are deployed in the environment to collect observations and preprocess the observations. Each sensor node has limited communication capability that allows it to communicate with other sensor nodes via a wireless channel. Normally, there is a fusion center that processes data from sensors and forms a global situational assessment. In a typical WSN, sensor nodes are powered by batteries, and hence have a very frugal energy budget. To maintain 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.
longer lifetimes of the sensors, all aspects of the network should be energy efficient. In [1], a data-centric energy efficient routing protocol is proposed. By using existing wireless local area network (WLA
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