Estimation and compensation of Doppler effect using variable sub-carrier spacing in multiband UAC OFDM systems

Doppler shift causes loss of orthogonality in Orthogonal Frequency Division Multiplexing (OFDM), which in turn may severely degrade receiver performance. In high data rate underwater acoustic communication (UAC), the effect of Doppler varies considerably over OFDM subcarriers. This paper will propose an algorithm to estimate the varying effects of Doppler shift over subcarriers and to avoid/mitigate the ICI produced by such effects using variable sub-carrier spacing in multiband OFDM.