Digital Acoustic Telemetry

Professor Baggeroer was one of the early pioneers who introduced digital acoustic telemetry in the oceans.

The early 1980s saw telemetry systems capable of achieving a (data-rate)(range) product of approximately 0.5 kbit-km. By the mid-1990s, fielded systems were achieving rates of nearly 40 kbitkm in shallow waters and approximately 100 kbit-km in deep waters. Much of this advance came with the introduction of coherent modulation systems and the concurrent availability of processors that could support the complex receiver algorithms being employed. Many other important advances have been made in the areas of high-rate incoherent modulation and error-control coding. Nonetheless, modern operation in more adverse channels would seem to require explicit incorporation of the underlying ocean-telemetry-channel physics. Professor Baggeroer and his students are using acousticpropagation models tailored to telemetry applications to further improve data rates. Channel characterization capturing the time variability of the channel is a necessary component of these models. With such a priori knowledge in hand, one can envision model-based receivers that can efficiently represent the challenging littoral and surf-zone environments currently under consideration.