An Improved Dictionary Design for Multicarrier Underwater Transmission

In this work, we study joint channel estimation and turbo equalization for coded orthogonal frequency division multiplexing (OFDM) in underwater acoustic (UWA) channels. We propose an alignment-aware basis (Aw-BS) design for compressed sensing (CS) based channel estimation that explicitly takes time alignment of the OFDM blocks into account after Doppler resampling and carrier frequency offset (CFO) compensation. Using the data collected from actual underwater experiments, our results show that the proposed Aw-BS design enhances the CS algorithm's ability to focus on dominant signal paths, and yields superior performance to existing works that use a fixed basis for the CS based channel estimation.