QoS-Oriented Asynchronous Clustering Protocol in Wireless Sensor Networks

The quality of service (QoS) to deliver time-and delay-sensitive data is critical in events-driven sensor network applications, which are constrained by energy consumption requirements. So far, most clustering proposals on this problem were based on periodic synchronous approaches, which require time synchronization and are not suitable for events-driven applications. We propose a QoS-oriented events-driven asynchronous clustering protocol, called EEAC (energy-efficient asynchronous clustering), which can deliver traffic in a timely and reliable manner. In EEAC, clustering starts asynchronously according to a probability, determined by cluster-heads' data transmission rate and residual energy. EEAC avoids time synchronization and adopts composite formula to elect cluster- heads. Simulation results show that EEAC ensures the real-time transmission of sensitive data, reduces the packet loss rate, and evenly distributes nodal energy consumption, thus prolonging network lifetime.