Today, wireless communications underwater could be used for many civil and military applications, such as oceanographic data collection, scientific sampling of oceans, pollution and environmental monitoring, climate recording, marine exploration, disaster prevention, assisted navigation, surveillance distributed tactics and mine recognition. Additionally, the transmission of wireless signals could also be used to remotely control the instruments in the oceanic observatories and to allow the coordination of autonomous underwater vehicles, which will play the role of mobile nodes in future oceanic observation networks thanks to their flexibility and configurability.
However, this type of communication presents a series of difficulties so that they can be carried out effectively. For example, the high attenuation and dispersion that affect radio waves and optics does not allow applications to be made at distances greater than one hundred meters. The bandwidth of the acoustic channel is quite limited and depends on the distance. In addition, there are high propagation delays, high bit error rates and temporary connectivity losses can be experienced, underwater devices are prone to faults due to scale and corrosion, and batteries have energy limitations and cannot be easily recharged.
Therefore, making submarine applications viable and efficient communication protocols between underwater devices, based for example on acoustics or optics, is highly complicated and requires great research efforts to facilitate the development of advanced techniques of underwater communication.
