  This paper provides an overview of how and why acoustic waves are important
for underwater communication when compared with radio and optical waves,
underwater acoustic channel, it's characteristics and model. Also about the
underwater sensor architecture, challenges faced by sensor nodes in the network
and Media Acess Control(MAC) protocol solutions for them. This paper also
describes about the various communication approaches including channel coding
in underwater and their performance analysis for different approaches used.
Through these approaches, multiple underwater vehicles can communicate among
themselves as well as with the console with minimal Bit Error Rate.
