Learn More
—We investigate turbo equalization, or iterative equalization and decoding, as a receiver technology for systems where data is protected by an error-correcting code, shuffled by an in-terleaver, and mapped onto a signal constellation for transmission over a frequency-selective channel with unknown time-varying channel impulse response. The focus is the(More)
— Low-complexity soft-in soft-out (SISO) equalizers based on time-varying linear filters and soft inter-symbol interference cancellation are known to be a viable alternative to the optimal trellis-based SISO equalizers when used in receivers based on iterative equalization and decoding. In particular, when the signal constellation is large and/or the(More)
—To combat the effect of intersymbol interference (ISI) while transmitting data over an ISI channel in a coded data transmission system, the impulse response of the channel is required. As part of the turbo equalization approach, which facilitates iterative equalization and decoding, we introduce a method to iteratively improve the quality of the estimate(More)
This is the authors' manuscript of the literature survey monograph " Underwater acoustic networking techniques " , published in the series " SpringerBriefs in Electrical and Computer Engineering ". The content is identical, but the published version has a much nicer layout, a handier format, and separate reference lists for each chapter. The authors have(More)
– In a receiver employing Turbo equalization for an unknown, time-varying, frequency-selective channel, the channel estimate can be improved for each iteration by using soft information fed back from the decoder. The reference signal to the channel estimator is then the expected value of each transmitted symbol and not the symbol itself. Therefore,(More)
This paper considers the application of iterative equalization and decoding, also known as Turbo equalization, to high frequency (HF) serial-tone modems. The soft-in soft-out (SISO) equalizer required for this approach is based on a linear filter, since a trellis-based equal-izer's computational complexity is too large for this application. Linear(More)
The theory of underwater sound interacting with the sea surface predicts a Gaussian-spread frequency spectrum in the case of a large Rayleigh parameter. However, recent channel soundings reveal more sharply peaked spectra with heavier tails. The measured Doppler spread increases with the frequency and differs between multipath arrivals. The overall Doppler(More)