Toward Performant and Energy-efficient Queries in Three-tier Wireless Sensor Networks

In a wireless sensor network (WSN) where nodes are mostly battery-powered, queries' energy consumption and response time are two of the most important metrics as they represent the network's sustainability and performance, respectively. Conventional techniques used to focus only one of the two metrics and did not attempt to optimize both in a coordinated manner. This work aims to achieve both high sustainability and high performance of WSN queries at the same time. To that end, a new mechanism is proposed to construct the topology of a three-tier WSN. The proposed mechanism eliminates routing tables and employs a novel and efficient addressing scheme inspired by the Chinese Remainder Theorem (CRT). The CRT-based topology allows for query parallelism, an unprecedented feature in WSNs. On top of the new topology encoded by CRT, a new protocol is designed to parallelly preprocess collected data on sensor nodes by effectively aggregating and deduplicating data in a neighborhood cluster. Moreover, a new algorithm is devised to allow the queries and results to be transmitted through low-power and fault-tolerant paths using recursive elections over a subset of the entire power range. With all these new techniques combined, the proposed system outperforms the state-of-the-art from various perspectives: (i) the query response is improved by up to 53%; (ii) the energy consumption is reduced by up to 70%; and (iii) the reliability is increased by up to 39%.