Consider typicalWSN applications involving the reliable de- tection and/or estimation of event features based on the collec- tive reports of several sensor nodes observing the event. Let us assume that for reliable temporal tracking, the sink must de- cide on the event features every time units. Here, represents the duration of a decision interval and is fixed by the applica- tion. At the end of each decision interval, the sink decides based on reports received from sensor nodes during that interval. The specifics of such a decision making process are application de- pendent and beyond the scope of our paper. The least we can assume is that the sink derives.
