5 research outputs found
On Capacity of Active Relaying in Magnetic Induction based Wireless Underground Sensor Networks
Wireless underground sensor networks (WUSNs) present a variety of new
research challenges. Magnetic induction (MI) based transmission has been
proposed to overcome the very harsh propagation conditions in underground
communications in recent years. In this approach, induction coils are utilized
as antennas in the sensor nodes. This solution achieves longer transmission
ranges compared to the traditional electromagnetic (EM) waves based approach.
Furthermore, a passive relaying technique has been proposed in the literature
where additional resonant circuits are deployed between the nodes. However,
this solution is shown to provide only a limited performance improvement under
practical system design contraints. In this work, the potential of an active
relay device is investigated which may improve the performance of the system by
combining the benefits of the traditional wireless relaying and the MI based
signal transmission.Comment: This paper has been accepted for presentation at IEEE ICC 2015. It
has 6 pages, 5 figures (4 colored), and 17 reference
Fields and coupling between coils embedded in conductive environments
An approximate solution is developed for the mutual inductance of two circular coils enclosed by insulating cavities in a conducting medium. This solution is used to investigate the variation of the mutual inductance upon the conductivity of the background (e.g., soil, seawater or human body), as well as upon other parameters such as the vertical of the coils and the displacement of one of the coils in the horizontal plane. Our theoretical results are compared with full wave simulations and a previous solution valid when a conductive slab is inserted between two coupled resonant coils. The proposed approach can have direct impact on the design and optimisation of magnetoinductive waveguides and wireless power transfer for underground/underwater networks and embedded biomedical systems
Underground Wireless Channel Bandwidth and Capacity
The UG channel bandwidth and capacity are vital parameters in wireless underground communication system design. In this chapter, a comprehensive analysis of the wireless underground channel capacity is presented. The impact of soil on return loss, bandwidth, and path loss is discussed. The results of underground multi-carrier modulation capacity are also outlined. Moreover, the single user capacity and multi-carrier capacity are also introduced with an in-depth treatment of soil texture, soil moisture, and distance effects on channel capacity. Finally, the chapter is concluded with a discussion of challenges and open research issues