On energy-efficient and low-latency medium access control in wireless sensor networks

In wireless sensor networks, one of the big challenges is to achieve a satisfactory network lifetime while meeting quality of service (QoS) requirements. In this paper, we propose a novel MAC layer protocol which provides energy efficiency, latency guarantee, adaptability and scalability for wireless sensor networks carrying on delay-sensitive applications. Different from existing schemes, our protocol applies an opportunistic sleep scheme to adaptively balance the tradeoff between energy efficiency and the end-to-end delay. Each sensor node maintains its own wakeup probability which is adaptively adjusted according to the local network conditions to reduce the energy consumption without the increased transmission latency. In addition, an energyaware antcast-based data forwarding scheme is introduced to further reduce sleep latency influence on the end-to-end delay and improve the communication reliability. We implement our protocol in the ns-2 simulator and compare with other protocols. Simulation results show that our protocol outperforms other protocols in terms of balancing the tradeoff between energy efficiency and the end-to-end delay.