EH-mulSEP: Energy-harvesting enabled multi-level SEP protocol for IoT-based heterogeneous WSNs

In this paper, we propose an improved hierarchical clustering protocol called EH-mulSEP (Energy-Harvesting enabled Multi-level Stable Election Protocol) for green IoT-based heterogeneous WSNs. We study the impact of energy-harvesting techniques in the large-scale systems by adding a number of energy-harvesting relay nodes that receive the aggregated data from the elected cluster heads and transmit to the base stations layer. Besides, we introduce a general formula for multi-level weighted election probability that can support up to n levels of heterogeneous nodes with their respective amounts of initial energies. For this, we leverage a state of the art heterogeneity method that considers more than three types of heterogeneous nodes and provides general models for higher levels of initial energy in WSNs. EH-mulSEP aims to minimize the total energy usage of battery-powered sensor nodes in IoT-based systems so as to maximize energy conservation, extend the network lifetime and ensure a higher level of scalability. The simulation results show that EH-mulSEP highly enhances the network performance in terms of stability, network lifetime, energy consumption, and throughput compared to other versions of SEP protocol in all conditions and scenarios tested.