Background & Objective: Underwater acoustic channels suffer from multipath, attenuation,
noise, frequency selectivity and Doppler effect. Finding efficient methods to communicate over such
very poor quality and high latency channels has been a challenge. A multipath underwater acoustic
channel can be seen as a sparse system, whose impulse response contains many zeroes and very few
large coefficients. The underwater digital communication research studies and experiments have been
developing over the last three decades leading to achievements and improvements since it started. This
field of communications would support so many sectors such as defense, marine research, marine
commercial operations, oceanography, and the offshore oil industry.
Conclusion: This paper provides a thorough overview of the latest research in the area of sparse underwater
wireless channels’ estimation and also presents brief proposals for future research directions
to enhance the accuracy of the underwater channel estimation.