Conductor-aware Wireless Underground Sensor Networks Based on Magnetic Induction: Research Challenges

Underground wireless communication technique facilitates various emerging applications such as structural monitoring and post-earthquake rescue, which is suffering from a significant reliability problem. Magnetic induction (MI) thus was introduced to enhance the underground wireless transmission channel, as it can provide steadier and more robust communication links. However, earthquakes and other geological activities can change the underground environment, such as increasing the conductive medium, making MI-based underground wireless communications more complex and challenging. To address this issue and alleviate the ongoing networking challenges, we propose a novel concept called MI-based conductor-aware wireless underground sensor networks (MI-CWUSNs) that adequately integrates the influence of conductor medium on links. The integration empowers MI-CWUSNs unique features such as complex-multipath channel, frequency-selectivity link, and directional-difference network, which create a huge resistance to achieving reliable data transmission in MI-CWUSNs. To unlock the potential of MI-CWUSNs, we provide a systematic research roadmap for MI-CWUSN data collection, spreading from channel modeling to air interface designing and to routing establishment. In particular, we list and analyze the underlying challenges and related future issues in each direction.