Event-Triggered Sleeping for Synchronous DC MAC IN WSNs: Mechanism and DTMC Modeling

Abstract

Overhearing and idle listening are two primary sources for unnecessary energy consumption in wireless sensor networks. Although introducing duty cycling in medium access control (MAC) reduces idle listening, it cannot avoid overhearing in a network with multiple contending nodes. In this paper, we propose an event-triggered sleeping (ETS) mechanism for synchronous duty-cycled (DC) MAC protocols in order to avoid overhearing when a node is not active. This ETS mechanism applies to any synchronous DC MAC protocols and makes them more energy efficient. Furthermore, we develop a two dimensional discrete time Markov chain model to evaluate the performance of the proposed ETS mechanism by integrating it to a popular synchronous DC MAC protocol namely sensor-MAC. Using the developed model, energy consumption, energy efficiency and network lifetime are calculated. Numerical results obtained through both analytical model and discrete-event simulations demonstrate the effectiveness of the ETS mechanism, represented by lower energy consumption, higher energy efficiency and longer lifetime when compared with the conventional control packet triggered sleeping mechanism.