Title :
Shallow underwater communication with passive phase conjugation and iterative demodulation and decoding
Author :
Keeser, Christopher ; Belzer, Benjamin J. ; Fischer, Thomas R.
Author_Institution :
Cypress Semicond., Lynnwood, WA
Abstract :
We propose passive phase conjugation (PPC) with iterative demodulation and decoding for communication over the shallow underwater acoustic channel. PPC mitigates inter-symbol interference (ISI) caused by multipath in the channel. A soft-input, soft-output (SISO) differential BPSK (DBPSK) demodulator and a SISO irregular repeat accumulate (IRA) channel decoder arranged in an iterative dasiaturbopsila structure improve the bit error rate (BER) at higher symbol rates. A linear estimator tracks channel phase variations arising from Doppler effects and wave motion. The system was tested at Lake Pend Oreille in Idaho over a distance of 1.78 km in shallow water with BERs below 10-5 at 2,500 information bits per second.
Keywords :
error statistics; intersymbol interference; iterative decoding; multipath channels; phase shift keying; underwater acoustic communication; BER; Doppler effects; Lake Pend Oreille; differential BPSK; distance 1.78 km; intersymbol interference; irregular repeat accumulate channel decoder; iterative decoding; iterative demodulation; iterative turbo structure; linear estimator; multipath channel; passive phase conjugation; shallow underwater acoustic channel; shallow underwater communication; soft- input soft-output; wave motion; Binary phase shift keying; Bit error rate; Demodulation; Intersymbol interference; Iterative decoding; Motion estimation; Phase estimation; Underwater acoustics; Underwater communication; Underwater tracking;
Conference_Titel :
Information Sciences and Systems, 2009. CISS 2009. 43rd Annual Conference on
Conference_Location :
Baltimore, MD
Print_ISBN :
978-1-4244-2733-8
Electronic_ISBN :
978-1-4244-2734-5
DOI :
10.1109/CISS.2009.5054846
