FOMA: Flexible overlay multi-path data aggregation in wireless sensor networks

Data aggregation is an efficient method to conserve energy by reducing packet transmissions in WSNs. However, providing end-to-end data reliability is a major challenge when the network uses data aggregation. In this case, a packet loss can miss a complete subtree of values, thus greatly affecting the final results. Data transmission in multiple paths can tolerate this problem, but it may incur some computation errors for duplicate-sensitive aggregates. In this paper, we propose a Flexible Overlay Multi-path data Aggregation protocol (FOMA) which uses the available path redundancy to deliver a correct aggregate result to the sink with high reliability in an energy-efficient manner. It aggregates data in two layers, routing layer and data aggregation layer, while eliminating the computation errors by using a signature-based method. We implement FOMA in TinyOs 2.x and test it by the TOSSIM simulator. The results reveal that the proposed algorithm outperforms other existing ones in terms of energy consumption and data accuracy.