Date Added: May 2012
Several time-domain receivers that adopt coherent modulation with an emphasis on channel equalization in order to increase communication reliability have been suggested. However, the time-varying doubly-spread characteristic of the UnderWater Acoustic (UWA) channel requires a highly complex equalizer. Recently, an alternative low-complexity, high-speed multicarrier communication system, in the form of OFDM, has attracted considerable interest in the field of UnderWater Acoustic Communication (UWAC). This is mainly due to its simplicity of operation by means of the Fast Fourier Transform (FFT) for the purpose of modulation/ demodulation. This system deals with the frequency selectivity of the channel by dividing the broadband data into parallel narrowband channels.