An energy-efficient and low-latency MAC protocol with Adaptive Scheduling for multi-hop wireless sensor networks

Medium access control (MAC) protocols play a crucial role in energy efficiency, latency reduction for sensor networks. Although some existing MAC protocols have achieved certain performance improvements, there are great potentials for further performance enhancement. In this paper, we propose a new MAC protocol called AS-MAC by introducing an Adaptive Scheduling (AS) period into the operational cycle within which the nodes' active duration is made adaptive to variable traffic load thus enabling AS-MAC to resiliently schedule data transmission in the sleep period. The algorithm is designated to schedule more data transmission in bursty and high traffic load, thus enabling rapid dissemination of data and reduction of latency. While under the light traffic load, nodes enter the sleep mode timely, mitigating idle listening and saving energy. Experiment results show that the proposed protocol is a great advancement of some existing protocols on the performance for both unicast and broadcast scenarios. Especially, under heavy unicast traffic load, AS-MAC can reduce end-to-end delay by about 65% and lowers energy consumption by about 40% compared to DW-MAC, while keeping nearly 100% packet delivery ratio.