Data Caching Based Queries in Multi-sink Sensor Networks

Considering limited storage space, limited energy and other constraints of sensors, a query mechanism based on data caching in Multi-Sink sensor networks is proposed. This mechanism extractes the common subtree of a network firstly, and then caches a sink's query results at the common root of a common subtree according to certain cashing strategies. When some other sinks submit the same query, it only needs to send the cached query results to the query sink. This data sharing mechanism based on common subtree caching can reduce communication cost obviously and improve query efficiency. In order to achieve a higher level of data sharing, we propose a Loop Removing Algorithm (LR) which can enlarge the size of a common subtree effectively. Simulation results indicate that the LR and the data caching based query processing method proposed in this paper can reduce the average energy consumption and response time of queries significantly.