Fundamentals and Advancements of Magnetic-Field Communication for Underwater Wireless Sensor Networks

Use of magnetic fields (MFs) for underwater wireless communication is very promising nowadays due to its advantages such as low power, low cost, no multipath, no Doppler effect, and instant communication. Considering the importance and potential of MF communication for underwater wireless sensor networks, this article presents a review on the fundamental concepts and theory of MF communication by identifying the main blocks, describing the limitation of each block and mentioning the advancements being done. The three fundamental blocks identified are: 1) the transmit and receive coils; 2) the matching network; and 3) the channel characteristics of the MFs. The first block explains how a single-dimensional coil is used to establish a directional communication link between a transmitter and a receiver and then the method by which the directionality problem is solved using multidimensional coils and metamaterial coils. Furthermore, the matching network explains the difference between the induction and resonance phenomena and their effect on the range and capacity. In the third block, the factors affecting the MFs are mentioned, which are critical to underwater wireless communication with MFs. Finally, this article introduces the recent advancements at the physical, MAC, and network layers.