Performance enhancement of blind adaptive equalizers using environmental knowledge

In this paper, a multichannel equalizer that utilizes information of the surrounding environment is proposed. The structure of this receiver consists of a bank of prefilters matched to the deterministic part of the channel impulse response, whose outputs are fed to a conventional blind multichannel equalizer. If information on the source-receiver geometry as well as physical properties of the channel are available the unknown impulse responses can be estimated using a numerical propagation model. Assuming a Pekeris model for the physical channel and utilizing a ray propagation, model the receiver structure is tested with measured shallow water data gathered during the ROBLINKS 1999 sea trial. The obtained results demonstrate that incorporating environmental knowledge into the signal processing scheme leads to an improved performance compared to a conventional blind receiver.

[1]  V. Barroso,et al.  Blind decision-feedback equalization of underwater acoustic channels , 1998, IEEE Oceanic Engineering Society. OCEANS'98. Conference Proceedings (Cat. No.98CH36259).

[2]  D. Jackson,et al.  Phase conjugation in underwater acoustics , 1991 .

[3]  A. Baggeroer,et al.  Acoustic telemetry - An overview , 1984, IEEE Journal of Oceanic Engineering.

[4]  Bayan S. Sharif,et al.  A blind multichannel combiner for long range underwater communications , 1997, 1997 IEEE International Conference on Acoustics, Speech, and Signal Processing.

[5]  Jean-Pierre Hermand,et al.  Acoustic model-based matched filter processing for fading time-dispersive ocean channels: theory and experiment , 1993 .

[6]  Philip Balaban,et al.  Optimum Diversity Combining and Equalization Digital Data Transmission with Applications , 1992 .

[7]  Johann F. Böhme,et al.  Initializing Blind Adaptive Equalizers Using A-Priori Environmental Knowledge , 2002 .

[8]  Sergio M. Jesus,et al.  UNDERWATER ACOUSTIC COMMUNICATION USING A "VIRTUAL" ELECTRONIC TIME-REVERSAL MIRROR APPROACH , 2000 .

[9]  C. H. Harrison,et al.  Modelling acoustic propagation in the time domain , 1998, IEEE Oceanic Engineering Society. OCEANS'98. Conference Proceedings (Cat. No.98CH36259).

[10]  Christopher D. Jones,et al.  Underwater acoustic communication using passive phase conjugation , 2001, MTS/IEEE Oceans 2001. An Ocean Odyssey. Conference Proceedings (IEEE Cat. No.01CH37295).

[11]  J. Gomes,et al.  A matched field processing approach to underwater acoustic communication , 1999, Oceans '99. MTS/IEEE. Riding the Crest into the 21st Century. Conference and Exhibition. Conference Proceedings (IEEE Cat. No.99CH37008).

[12]  W. Kuperman,et al.  Phase conjugation in the ocean: Experimental demonstration of an acoustic time-reversal mirror , 1998 .

[13]  Milica Stojanovic,et al.  Recent advances in high-speed underwater acoustic communications , 1996 .

[14]  J. Proakis,et al.  Adaptive multichannel combining and equalization for underwater acoustic communications , 1993 .

[15]  C. Pekeris.  THEORY OF PROPAGATION OF EXPLOSIVE SOUND IN SHALLOW WATER , 1948 .

[16]  R. Weber,et al.  Blind receivers for MSK signals transmitted through shallow water , 2001, MTS/IEEE Oceans 2001. An Ocean Odyssey. Conference Proceedings (IEEE Cat. No.01CH37295).