Abstract
During a 12-h period in the 2006 Shallow Water Experiment (SW06), binary phase shift keying (BPSK) signals at the carrier frequencies of 813 and 1627 Hz were propagated over a 19.8-km sourcereceiver range when a packet of strong internal waves passed through the acoustic track. The communication data are analyzed by time reversal processing followed by a single-channel decision feedback equalizer. Two types of internal wave effects are investigated in the context of acoustic communications. One is the rapid channel fluctuation within 90-s data packets. It can be characterized as decreased channel coherence, which was the result of fast sound-speed perturbations during the internal wave passage. We show its effect on the time reversal receiver performance and apply channel tracking in the receiver to counteract such fluctuation. The other one is the long-term (in the scale of hours) performance degradation in the depressed waveguide when the internal waves passed through the acoustic track. Even with channel tracking, the time reversal receiver experiences average 34-dB decrease in the output signal-to-noise ratio (SNR). Such long-term performance degradation is explained by the ray approximation in the depressed waveguide.
Original language | English |
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Article number | 5618583 |
Pages (from-to) | 756-765 |
Number of pages | 10 |
Journal | IEEE Journal of Oceanic Engineering |
Volume | 35 |
Issue number | 4 |
DOIs | |
State | Published - Oct 2010 |
Externally published | Yes |
Bibliographical note
Funding Information:Manuscript received February 03, 2009; revised December 23, 2009, March 17, 2010, and June 25, 2010; accepted June 26, 2010. Date of publication November 09, 2010; date of current version November 30, 2010. This work was supported by the U.S. Office of Naval Research (ONR) Code 322OA under Grants N00014-07-1-0546 and N00014-06-1019. Associate Editor: H. Song. A. Song and M. Badiey are with the College of Earth, Ocean, and Environment, University of Delaware, Newark, DE 19716 USA (e-mail: ajsong@udel. edu). A. E. Newhall and J. F. Lynch are with the Department of Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, MA 02543 USA. H. A. DeFerrari is with the Division of Applied Marine Physics, University of Miami, Miami, FL 33149 USA. Boris G. Katsnelson is with the Physics Department, Voronezh State University, Voronezh 394006, Russia. Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/JOE.2010.2060530
Keywords
- Acoustic communications
- decision feedback equalizers
- internal waves
- time reversal processing
ASJC Scopus subject areas
- Ocean Engineering
- Mechanical Engineering
- Electrical and Electronic Engineering