Research Summaries

Back Time and Frequency Relationships of an FFT-Based Acoustic Modem

Fiscal Year 2010
Division Graduate School of Engineering & Applied Science
Department Physics
Investigator(s) Jenkins, William F.
Sponsor Space & Naval Warfare Systems Center-Pacific (Navy)
Summary The goal of this research is to implement MFSK modulation for underwater acoustic communications in an adaptive manner by exploiting basic time-frequency relationships. Signal parameters such as spectral bandwidth and symbol duration may be adjusted on a packet-by-packet basis such that transmitted acoustic signals are well matched to the physical through-water communications medium and its prevailing channel scattering function.
This research will be an analytical comparison of the advantages and disadvantages of using bandwidth scaling and bandwidth multiplexing at the high frequencies at which Seastar short-range underwater acoustic modems operate. As such, the scope of this research will be defined by any case studies that are modeled, and by any experimental data that are acquired either from the laboratory or from sea trials.
The immediate contribution of this research will be to determine a more efficient method of transmitting digital data at high frequencies through the short-range (50-500 m) underwater acoustic channel. Currently, NPS is in possession of two high frequency modems as part of the Seastar project. The results of this research will directly impact their operational roles in the development of the Seastar network, as well as the greater Seaweb network. Organizations that will benefit from this work include SPAWAR and NRL.
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Publications Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal
Data Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal