Data and query dissemination in wireless sensor networks

This paper deals with the issue of communicating data and queries among the sensor nodes by wireless transmission. The nodes have limited battery power, memory and processing capacities. We assume that each node is aware of its geographic location, but the nodes do not have a priori information about the details of other nodes in the neighbourhood. Nodes detect events; and queries are posed by an external source or one of the internal nodes. The question is of data and query dissemination: where to store the event details and how to efficiently provide answers to the queries. When an event is detected by a node, it can be stored locally in the node, in some other node or in an external node. The queries have to be routed accordingly. The corresponding canonical methods are called as local, data centric and external storage techniques (S. Shenker et al., 2002). In this paper we propose an indexed data dissemination technique. A designated node, possibly the link node, maintains an index list of all nodes that have detected an event type in the network. The queries are appropriately routed using the index. We have provided an analysis of the cost benefit of the technique, in relation to the prior techniques. Our results indicate that the proposed technique outperforms the others when the number of events is large in comparison to the number of nodes