Characteristics of Underground Channel for Wireless Underground Sensor Networks

Wireless Underground Sensor Networks (WUSN) constitute one of the promising application areas of the recently developed wireless sensor networking techniques. The main difference between WUSN and the terrestrial wireless sensor networks is the communication medium. The propagation characteristics of electromagnetic (EM) waves in soil and the significant differences between propagation in air prevent a straightforward characterization of the underground wireless channel. To this end, in this paper, advanced channel models are proposed to completely characterize the underground wireless channel and lay out the foundations for efficient communication in this environment. In particular, the underground communication channel is modeled considering not only the propagation of EM waves in soil, but also other affects such as multipath, soil composition, water content, and burial depth. The propagation characteristics are shown through simulation results of path loss between two underground sensors. Moreover, based on the proposed channel model, the resulting bit error rate is analyzed for different network and soil parameters. The theoretical analysis and the simulation results prove the feasibility of wireless communication in underground environment and highlight several important aspects in this field. This work will lead to the provision of a generic framework for underground wireless communication and the realization of WUSN.