Multiuser undersea acoustic communications in the presence of multipath propagation

2002 ◽  
Author(s):  
M. Stojanovic ◽  
L. Freitag
Keyword(s):  
Multipath Propagation ◽  
Acoustic Communications

scholarly journals Combined Hybrid DFE and CCK Remodulator for Medium-Range Single-Carrier Underwater Acoustic Communications

2017 ◽  
Vol 2017 ◽  
pp. 1-11
Author(s):  
Xialin Jiang ◽  
Wei Su ◽  
En Cheng
Keyword(s):  
Frequency Domain ◽  
Multipath Propagation ◽  
Underwater Acoustic Communications ◽  
Acoustic Communications ◽  
Detection Scheme ◽  
Underwater Acoustic ◽  
Time Frequency ◽  
Single Carrier ◽  
Medium Range ◽  
Underwater Acoustic Channels

Advanced modulation and channel equalization techniques are essential for improving the performance of medium-range single-carrier underwater acoustic communications. In this paper, an enhanced detection scheme, hybrid time-frequency domain decision feedback equalizer (DFE) combined with complementary code keying (CCK) remodulator, is presented. CCK modulation technique provides strong tolerance to intersymbol interference caused by multipath propagation in underwater acoustic channels. The conventional hybrid DFE, using a frequency domain feedforward filter and a time domain feedback filter, provides good performance along with low computational complexity. The error propagation in the feedback filter, caused by feedbacking wrong decisions prior to CCK demodulation, may lead to great performance degradation. In our proposed scheme, with the help of CCK coding gain, more accurate remodulated CCK chips can be used as feedback. The proposed detection scheme is tested by the practical ocean experiments. The experimental results show that the proposed detection scheme ensures robust communications over 10-kilometre underwater acoustic channels with the data rate at 5 Kbits/s in 3 kHz of channel bandwidth.

ADAPTIVE BEAMFORMING FOR ACOUSTIC COMMUNICATIONS

1990 ◽  
Vol 51 (C2) ◽  
pp. C2-699-C2-702
Author(s):  
G. S. HOWE ◽  
O. R. HINTON ◽  
A. E. ADAMS ◽  
A. G.J. HOLT
Keyword(s):  
Adaptive Beamforming ◽  
Acoustic Communications
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