The problem of multi-user access in undersea networks

Underwater acoustic networks (UWANs) can be applied in a vast range of applications. Unlike terrestrial networks, UWANs suffer from a much harsher communication environment. This paper starts by discussing the underwater environment characters, and examines the challenges in designing UWANs in detail. Although terrestrial MAC protocols have been extensively studied for a long time, they are not suitable in UWANs. This paper then discusses newly proposed MAC protocols tailored for UWANs by dividing them into broad categories according to their focus and strategies. Our further work will be simulating some proposed underwater acoustic MAC (UWA-MAC) protocols and then arranging practical underwater experiments to test their performance.