Event Driven Protocols for Energy Efficient Wireless Sensor Networks

Abstract

As human sensory structures are often restricted to sensing a small range of visual, hearing, smell, taste, and touch events, the need for extending humans’ limited sensory abilities has been a driving force for research, inventions and innovations that have led to discoveries of tools such as wireless sensor nodes. Wireless sensor nodes are inexpensive, multifunctional devices capable of extending humans’ limited sensory abilities and they can be used easily to form wireless sensor networks (WSNs), which have a wide range of potential applications. Since wireless sensor nodes are typically battery-powered, a major concern in the design of WSNs is energy conservation as these networks are expected to operate autonomously for long periods. Therefore, this thesis presents a thorough research effort that has investigated ways of improving energy efficiency of WSNs. First, a theoretical model of a WSN’s lifetime was established. The model includes collaborative communication and enabled communication techniques to be identified that minimize idle listening and maximise collision avoidance, both of which waste energy. Then the Collaborative Event Driven Energy Efficient Protocol (CEDEEP), which ensures energyefficient operation of one-hop, event-driven WSNs, was introduced. CEDEEP takes advantage of the spatiotemporal correlation of wireless sensor nodes’ reporting in event-driven WSNs and uses collaborative communication to conserve energy. The presented analytical results prove the viability of this approach and show that CEDEEP offers considerable improvements in energy efficiency. Subsequently, a novel Energy Efficient Collision Avoidance Method (EECAM) for CEDEEP was proposed. EECAM makes possible higher energy savings by introducing node prioritization based on the distinctive properties of the CEDEEP protocol and event-driven WSN applications. Furthermore, a stochastic model of the one-hop network was developed and the higher energy efficiency of CEDEEP with EECAM was illustrated using the IEEE 802.15.4 and Sift protocols. Therefore, this thesis provides diverse analytical models and offers strong evidence that use of CEDEEP with EECAM, as an event-driven protocol, contributes considerably to the energy efficiency of event-driven WSNs. In this way not only has a superior event-driven protocol been proposed, but a robust basis for future research focused on energy-efficient, event-driven protocols for WSNs has been established.