Structure-free real-time data aggregation in wireless sensor networks

Data aggregation is a very important method to conserve energy by eliminating the inherent redundancy of raw data in dense WSNs. Although structured approaches are particularly useful for data gathering applications, they incur high maintenance overhead in dynamic scenarios for event-based applications. Moreover, a WSN should be capable of timely fulfilling its mission without losing important information in event-critical applications. In this paper, we focus on designing a structure-free Real-time data AGgregation protocol, RAG, using two mechanisms for temporal and spatial convergence of packets - Judiciously Waiting policy and Real-time Data-aware Anycasting policy. Using extensive simulations in NS-2, we investigate the performance of RAG in terms of aggregation gain, miss ratio, energy consumption, and end-to-end delay for WSNs. (C) 2011 Elsevier B.V. All rights reserved.