Service-Driven Query Routing in Sensor Networks

Query processing in sensor networks entails three phases: (i) query routing, (ii) query evaluation, and (iii) aggregating results and routing them back to the query source. Most existing query routing approaches are "overreaching", i.e., they use broadcasting schemes where nodes use some default transmission power to broadcast queries to all of their neighbors. Moreover, current routing schemes generally do not exploit the semantics of queries. As a result, a query may be routed through several hops to end up at nodes that do not provide the sensing capabilities that it requires or that do not have paths to nodes that provide the required capabilities. This obviously incurs excessive communication and processing overhead that is not strictly required to deliver the query to its recipients. To address these deficiencies, we introduce the notion of service-driven query routing (SQR) which is a routing scheme based on the idea of modeling nodes\´ capabilities as services. In SQR, nodes maintain local information about their neighbors\´ services. They combine this information with the queries\´ semantics to determine efficient routing paths and minimal radio transmission power levels when forwarding queries to their neighbors