جلوگیری از اطلاعات Decision-aware در شبکه های حسگر بی سیم برای برنامه های ردیابی هدف Decision-aware data suppression in wireless sensor networks for target tracking applications

1 Introduction Wireless sensor networks (WSNs) have demonstrated a great potential for a wide range of control applications, including building automation, industrial control systems, electricutility automation, military systems, road traffic control, inventory management, and target tracking [1–6]. In this kind of applications, data registered by sensor nodes are transferred wirelessly to a sink node. The sensor readings collected at sink node are then utilized for decision making. Such applications can provide a high performance only if the WSN ensures a reliable and timely data delivery. Transmission failures, delays and energy depletion of sensor nodes may result in non-optimal decisions. The probability of transmission failure and transmission delay as well as the energy consumption can be reduced by decreasing the amount of transmitted data [7]. Thus, minimization of data transfers from sensor nodes is an important research issue for the development of WSN applications. Data suppression is an approach to collect necessary information at a sink node, while reducing the data transfers from sensor nodes as much as possible [8,9]. When using suppression schemes, each sensor node collects data with a high sampling rate but sends only those data readings that represent a deviation from an expected behavior. Thus, the WSN is able to quickly recognize relevant events in the monitored environment. This cannot be ensured in case of adaptive sampling methods that reduce the data communication by adjusting the sampling rates of sensor nodes according to previously collected readings [10,11]. When using the adaptive sampling methods, the sampling rate is reduced if the previous measurements show that changes in a monitored process are slow. In such case, the information about unexpected abrupt changes of the monitored parameters may be missed or delivered with excessive delay. In such situation, the collected information would be insufficient for the target tracking applications. For instance, when the target remains in the same location for a long time and then moves rapidly to a new location, the new location may be reported belatedly and in result the tracking performance would be decreased. In this paper, a decision-aware data suppression approach is proposed for target chasing in WSNs. The aim of the considered target chasing task is to catch a moving target by a mobile sink in the shortest time. The mobile sink has to make decisions, i.e., select its movement direction, based on information about target position delivered from sensor nodes.