Performance of hydro-acoustic data transmission in horizontal channels using sweep-spread signaling and turbo-coding

Using the sweep-spread carrier it can be demonstrated that in result of optimal filtering of dominated (synchronous) multipath all other (non-synchronous) multipaths become attenuated. This causes an increase of the ratio between the energy of synchronous multipath component and scattered energy of non-synchronous multipaths. Thus the probability distributions of signal envelope and phase become closer to Gaussian one. So the use of the sweep-spread carrier in hydro-acoustic channels allows for application of turbo-codes, what, in turn, leads to increase of reliability of data transmission under condition of low ratios between signal energy and the energy of ambient noise (few decibels). The paper characterizes performance of a receiver combining the optimal quadrature demodulator and turbo-decoder.