Payload-Adaptive Hybrid MAC Protocol for Sustainable Internet of Things Networks

Wireless energy transfer technology enables internet of things networks to have longer lifetime without the need of frequent battery replacements. Given the constrained computational resources and energy storage of sensors, the design of Medium Access Control (MAC) protocols demands targeted consideration. This paper proposes a hybrid MAC protocol for data reporting collection within radio frequency energy harvesting enhanced internet of things networks. The proposed protocol employs differentiated access strategies based on the payload size of data packets. When dealing with smaller data packets, sensors swiftly access the network through a contention-based access mechanism. Conversely, when encountering larger data packets, sensors split the packet and then utilize the first segment to compete for dedicated time slots for transmitting subsequent packets. Furthermore, leveraging synchronization mechanisms, the coordinator periodically dispatches energy packets to replenish the battery of all sensors. Through simulations comparing with both contention-based protocol CSMA/CA and a slot allocation protocol, our proposed protocol demonstrates lower energy consumption in low-traffic scenarios. Conversely, in high-traffic scenarios, it demonstrates higher throughput, lower latency, and lower energy consumption.