Through-The-Earth Magneto-Quasi-Static OFDM Transmission

Through-The-Earth Magneto-Quasi-Static OFDM Transmission
April, 16, 2018
Room 1061 Electrical Eng. Building Technion City

Electro-Optics and Microelectronics Seminar

Graduate Seminar

Speaker: Lior Kissos
Affiliation: Electrical Eng., Technion

Recent years have witnessed an ever-growing need for a high-rate reliable Through-The-Earth (TTE) communication: two-way links between ground surface and underground devices separated by 10’s to 100’s of meters of soil. Such necessity has emerged in defense applications as well as in civilian applications such as the mining industry.
The Electro-Magnetic (EM) field characteristics in the weakly conducting underground medium, are best utilized for communication in the Very Low Frequency (VLF) spectral band, which corresponding to the magneto-quasi-static regime.
Although some commercial TTE communications transceivers have been developed, they all assume fixed deployment, are based on relatively old communication technologies and exhibit relatively poor performance.
We propose a modern approach of a TTE communication system integrating highly efficient and sensitive Magneto- Inductive analog hardware, together with state-of-the-art Digital Signal Processing communication formats and algorithms, adopting the Orthogonal Frequency Division Multiplexing (OFDM) transmission format. To our knowledge, such an approach has not been pursued so far. Our main achievement is a demonstration of an end-to-end TTE communication link tested in a real-time transmission of voice scenario, across several floors of a building. The system is realized with relatively lightweight analog equipment (comparing to the commercial transceivers including their antenna systems). Our system features state-of-the communication methods, namely the Software Defined Radio (SDR) architecture, PAPR reduction, MIMO equalization, Frequency & phase combined improved estimation, Improved channel estimation.

*MSc. student under the supervision of Prof. Moshe Nazarathy