STDCS: A Spatio-Temporal Data-Centric Storage Scheme For Real-Time Sensornet Applications

Sensor networks will shortly consist of globally deployed sensors providing real-time geo-centric information to users. Particularly, users with mobile devices will issue ad-hoc queries usually from within, or nearby, the queried area. In this paper, we propose an in- network data-centric storage (DCS) scheme, namely the spatio-temporal data-centric storage (STDCS) scheme, to efficiently answer these mobile user queries. STDCS is designed to maintain load-balancing among sensors to cope with query hotspots in the network. It is different from previous proposals in two aspects. First, it is based on the novel idea of using a temporally evolving spatial indexing scheme to balance querying load among sensors. Furthermore, STDCS uses dynamic mechanisms for query hotspot detection and decomposition. We conducted extensive simulations that showed our scheme´s superiority to both local storage and spatial indexing (the only known geo-centric storage schemes) whenever experiencing query hotspots of different sizes.