An Area-Based Overlay Architecture for Scalable Integration of Sensor Networks

With many different sensor networks being deployed, there will be an increased need to facilitate their uniform and efficient access at a large, perhaps even global, scale. To this end, we present an overlay-based architecture for organizing and querying multiple sensor networks based on their geographical area. The nodes of the system, representing query processors and individual sensor network gateways, are organized in a hierarchy which is used for query forwarding and result delivery. The key features of our system are: (i) support for the dynamic addition and removal of query processors and sensor network gateways; (ii) automatic hierarchy construction and awareness of sensing capabilities based on explicit metadata information; and (iii) efficient query multiplexing and result de-multiplexing within the overlay. We present a first evaluation of the proposed architecture. Results indicate that our design considerably reduces the communication between the nodes of the overlay as well as the actual sensing load at the edges (sensor networks) of the system.