摘要： Underwater acoustic (UWA) channels are characterized by a severe spread in time and frequency, and are usually labeled as “doubly spread channels.” In this paper, we propose Doppler-resilient orthogonal signal-division multiplexing (D–OSDM), to provide a highly reliable communication environment in doubly spread channels for UWA communication. D–OSDM multiplexes several data vectors in addition to a pilot vector, and preserves orthogonality among them even after propagation through doubly spread channels, under the assumption that the channel can be modeled by a basis expansion model (BEM). We describe the signal processing steps at the transmitter and the receiver for D–OSDM, and evaluate its performance by both simulations and experiments. To generate a doubly spread channel, a test tank with a wave generator is employed. The obtained results suggest that D–OSDM can provide low-power and high-quality UWA communications in channels with large delay and Doppler spreads; for example, D–OSDM succeeds to achieve a block error rate (BLER) of 10 while BEM-based orthogonal frequency-division multiplexing (OFDM) has a BLER ?oor of in the experiments. Equivalently, D–OSDM can reduce the 10 signal power required for communications to achieve the same BER signi?cantly. Overall, it was found that D–OSDM can become a powerful communication tool for underwater operations.