Researchers at Scripps Institution of Oceanography and NATO Undersea Research Center have developed an “acoustic time reversal” technique that boosts underwater wireless broadband speed by up to three times, or extends the range up to 3500 km.

The system compensates for reduced signal/noise ratio due to phase-delay artifacts from surface and sea-bottom echoes. A receiver first transmits an acoustic carrier signal. The sender then time-reverses what they receive, and also modulates the signal to carry a message.