Prediction based sparse channel estimation for underwater acoustic OFDM

• A time domain predictor is proposed by exploiting the sparse features of underwater acoustic channel.
• Doppler shift is taken into account.
• Different channel estimation methods are compared for a better channel prediction performance.
• Simulated results and experimental results are carried out to verify the proposed methods.

Channel prediction has been becoming the key technique in adaptive underwater acoustic communication systems because it is always a challenge to transmit the exact channel state information back to transmitter in the range of several kilometers. In this paper, we focus on exploring a time domain predictor by exploiting the sparse features of underwater acoustic channel for OFDM systems. At the same time, it takes the presence of Doppler shifts into account. Different channel estimation methods are compared for a better channel prediction performance. The complexity of the proposed algorithm is low, because only a small number of significant channel paths are predicted. Simulated results and experimental results show that our proposed method has a better performance, and it is able to present a time domain predictor in an underwater acoustic channel and provide reliable channel state information (CSI) to the transmitter. According to the reliable CSI, an adaptive underwater acoustic communication system can be established and function well.