DocumentCode :
1953160
Title :
Underwater acoustic communication using time reversal
Author :
Edelmann, G.F. ; Hodgkiss, W.S. ; Kim, S. ; Kuperman, W.A. ; Song, H.C. ; Akal, T.
Author_Institution :
Marine Phys. Lab., California Univ., San Diego, La Jolla, CA, USA
Volume :
4
fYear :
2001
fDate :
2001
Firstpage :
2231
Abstract :
Time reversal, or phase-conjugation, refocuses energy back to a probe source location despite the complexity of the propagation channel. A probe source pulse is transmitted and a complicated multipath signal is measured by an array of source/receiver elements. The signal is time reversed and retransmitted into the ocean. The time-reversal process recombines this temporal multipath at the original probe source range and depth. The ability of time reversal to reduce dispersion and its simplicity of implementation makes it ideal for underwater acoustic communications, which must mitigate the inter-symbol interference caused by the time-varying multipath dispersion. Furthermore, time reversal focuses energy at the desired depth, thus mitigating the effects of channel fading. An experiment was conducted in June 2000 demonstrating that the time-reversal process recombined the temporal multipath resulting in reduced bit errors for communication. Communication sequences were transmitted over a distance of 10 km both in range independent and range dependent environments north of Elba Island, Italy. The range independent transmissions were made in 110-m deep water and the range dependent transmissions were made upslope from 110-m deep water into 40-m deep water. Single source transmissions were also measured in the same channels. Quantitative bit error results are shown for BPSK (binary phase shift keying) and QPSK (quadrature phase shift keying)
Keywords :
dispersive channels; fading channels; interference suppression; intersymbol interference; multipath channels; quadrature phase shift keying; time-varying channels; underwater acoustic communication; 10 km; BPSK; Elba Island; Italy; QPSK; binary phase shift keying; bit errors; channel fading; communication sequences; depth; dispersion; inter-symbol interference; multipath signal; phase-conjugation; probe source location; probe source pulse; propagation channel; quadrature phase shift keying; range independent transmissions; time reversal; time-varying multipath dispersion; underwater acoustic communication; Acoustic propagation; Acoustic pulses; Binary phase shift keying; Position measurement; Probes; Pulse measurements; Quadrature phase shift keying; Sea measurements; Underwater acoustics; Underwater communication;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
OCEANS, 2001. MTS/IEEE Conference and Exhibition
Conference_Location :
Honolulu, HI
Print_ISBN :
0-933957-28-9
Type :
conf
DOI :
10.1109/OCEANS.2001.968345
Filename :
968345
Link To Document :
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