Differentially Coherent Detection of OFDM Signals in Underwater Acoustic Channels

Abstract

We propose a low complexity array processing method for differentially coherent detection of OFDM signals over underwater acoustic channels. The proposed method employs partial FFT demodulation technique and fractionally spaced equalization to mitigate the inter-carrier interference (ICI). Results from simulations and recent experiments show that the employed ICI mitigation techniques successfully mitigate Doppler distortions and enable the differentially coherent detection to outperform the coherent detection in cases where motion in the channel limits the performance.