3aUW12. Sea-surface roughness effect on underwater coherent acoustic communications.

Session: Wednesday Morning, December 4

Time: 10:44

Author: Azmi A. Al-Kurd
Location: Naval Res. Lab., Code 7120, Washington, DC 20375


The ocean represents a band-limited, temporally unstable multipath, and rapidly fading communication channel. Although the joint implementation of an adaptive decision feedback equalizer and phase-locked loop synchronizer updates the receiver filter coefficients to offset the signal error introduced by the time-varying channel transfer function, the effects of the temporal variation on the symbol rate and bit error rate have not been quantitatively investigated. This is because several oceanographic processes with inherently different temporal and spatial scales are simultaneously contributing to the amplitude and phase fluctuations of the signal; these factors are not easily isolated in the received data. In this study a full-field wave propagation code is used to simulate the transfer function for a temporally varying oceanic waveguide. An exact and approximate methods are being used to compute the rough surface scatter. The signal intensity and phase fluctuation statistics are investigated, and the effect of the magnitude, spatial coherence, and temporal variabilities of the surface roughness on the maximum communication data rate and the average bit error rate are being evaluated.

ASA 132nd meeting - Hawaii, December 1996