Bidirectional data aggregation scheme for wireless sensor networks

In this paper, bidirectional data aggregation (BDA) scheme is proposed for wireless sensor networks. Traditionally, data aggregation bas been performed in backward direction (from source to sink) where each node in the network combines data from its child nodes. BDA algorithm, however, aggregates sensory data in both directions (sink to sources and sources to sink) when the sink is interested in gathering singular aggregates such as MAX and MIN. In forward aggregation (sink to sources), each node tags its sensor reading to the ongoing query only if its local reading is not redundant. Node receiving the tagged query suppresses its response if its local reading is redundant. By doing so, we can limit a number of redundant and unnecessary responses from the sensor nodes, saving energy. Performance evaluation shows that BDA algorithm significantly improves energy-efficiency as well as provides an accurate response for a given singular query in the presence of time-varying sensor readings.