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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 interleaver, 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)
Abstract—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(More)
We address the problem of improving the throughput and the availability of digital communications in the High Frequency (HF, 3-30 MHz) band. In standardized military waveforms, the data is protected by an error-correcting code (ECC), and the code bits are shuffled by an interleaver and mapped onto a signal constellation for modulation onto a single carrier.(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, classical(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)
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)