Continuous monitoring using event-driven reporting for cluster-based wireless sensor networks

Continuous-monitoring applications are an important class of wireless sensor network (WSN) applications. These applications require periodic refreshed data information at the sink nodes. To date, this entails the need for the sensor nodes to continuously transmit in a periodic fashion to the sink nodes, which may lead to excessive energy consumption. In this paper, we show that continuous monitoring does not necessarily imply continuous reporting. Instead, we demonstrate that we can achieve continuous monitoring using an event-driven reporting approach. Building on this idea, we propose two new mechanisms that enable energy conservation in continuous-monitoring WSNs. The first mechanism can augment any existing protocol, whereas the second mechanism is conceived for cluster-based WSNs. With both mechanisms, sensor nodes only transmit information whenever they sense relevant data. To evaluate the efficiency of our proposals, the basic unscheduled transmission model and three well-known cluster-based protocols are used as baseline examples. In particular, new analytical models for conventional cluster-based systems and for our approach-enabled systems are complemented by simulations to present a quantified perspective of the potential benefits of the proposed reporting technique. We prove that significant energy conservation can be achieved using our reporting approach.