Characterization and receiver design for underwater acoustic channels with large Doppler spread

A time-varying underwater acoustic channel consists of multiple propagation paths which could have drastically distinct Doppler scaling factors. For example, in a communication scenario with mobile nodes, some paths might experience positive Doppler scales while others have negative Doppler scales, leading to a large Doppler spread. In this work, we address two issues. First, we quantify the channel Doppler spread of an underwater acoustic channel based on the instantaneous channel estimate from a probing signal. Second, we develop an OFDM receiver specifically for channels with large Doppler spread. Data sets collected from a swimming pool with a moving node are used for channel characterization and performance evaluation.