DOPPLER SHIFT ESTIMATION FOR UNDERWATER ACOUSTIC COMMUNICATION SYSTEM

Underwater Communication has been a thrust area for researchers and engineers. The major challenges faced in this underwater acoustic channel are due to multipath, frequency selective absorption, noise, and the Doppler Effect which is very much different from the terrestrial channel. Of all the challenges in UAC, this paper provides two robust techniques for Doppler Shift Estimation. The Doppler Shift estimation is performed at the receiver using any one of the two techniques; Preamble based method or MUSIC algorithm. Using these two techniques, the Doppler Shift within an OFDM frame is estimated in this paper. Based on estimated shift, compensation is performed later in frequency domain to reduce the errors.