A Novel Hybrid MAC Protocol for Sustainable Delay-Tolerant Wireless Sensor Networks

Efficient MAC protocols are fundamental to conserve energy and enable sustainable delay-tolerant sensor networks (DTSNs). They can be explored to reduce energy consumption, deal with relaxed latency requirements, support mobility and address diverse traffic loads. In this paper, we theoretically analyze the performance of reservation-based and contention-based MAC protocols in DTSNs regarding throughput and energy consumption, respectively. According to the derived theoretical results, we propose a TRaffic-adaptive energy-efficient MAC protocol (TREEM) to achieve better data transmissions as well as energy efficiency, in order to satisfy DTSN requirements. More precisely, our protocol can dynamically switch its working mode between contention and reservation to adapt to the varying data traffic. In addition, to further improve the energy efficiency of DTSN, our algorithm can also calculate the more suitable duty/active period length. The simulation results of TREEM demonstrate better performance in terms of energy efficiency and traffic adaptability than the schedule-based MAC protocol TDMA, the contention-based protocol CSMA, and the traffic-adaptive protocol TRAMA under mobile DTSN environments.