Underwater communications

Maxwell first described the theoretical basis for the propagation of electromagnetic waves in 1873[1]. For the next 140 years we have seen tremendous developments in the area of Wireless Communications. Today, virtually everything in the world is connected by wireless technologies, whether it´s on the surface of earth or in the deep space. Surprisingly, an important frontier is left out, which occupies 70% of our planet, where wireless technology has not able to penetrate so far. This is the underwater world, 95% of which is not yet explored. It is strange that we are able to communicate with farthest human made object (Voyager-1, ~10¹¹km away from earth) using few watts of power (18Watts in the high power mode) [2], but we don´t have reliable communication link with our strategic nuclear submarines lying few meters down the sea, in spite of the fact that we are pumping megawatts of power in the ELF/VLF facilities for one way communication with submarines. Fortunately, the new developments happening in the area wireless acoustic communications over last decade has made it possible for the first time to tweet the aquanauts from the bottom of Mariana Trench, the deepest point on the planet. This paper/presentation will cover some of the interesting sequence of events which has made it possible and the challenges that we are facing today in conquering the final frontier for wireless: the underwater.