Multilevel sensor deployment approach in IIoT-based environmental monitoring system in underground coal mines

The Bord and Pillar methods are widely popular in an underground coal mine. Continuous monitoring of the environment is crucial to ensure the safety of miners. The Industrial Internet of Things (IIoT) is the contemporary technological advancement of wireless networks that makes environmental monitoring more sophisticated. However, deployment of sensor nodes is a complicated task as it is linear in structure. Furthermore, it is prone to failure owing to energy drain near the sink node. This paper proposes a hybrid sensor deployment approach which is implemented in a linear and integrated mine networks. This hybrid approach is an integration of two sensor deployment methods namely multi-level and grid methods. The simulation results prove that the proposed technique enhances the network's lifetime by limiting the tunneling effect near the sink. Furthermore, it uses more than 80% of the mean energy in the network system, compared to previous algorithms, which frequently fail even before utilizing 50% of the energy, and in some circumstances, even less. Hence, the proposed method brings an economic benefit by expanding the lifespan of the network through an increased number of nodes around the sink and minimizes the tunneling effect at each level in the network.