Title :
Communication over Doppler spread channels. Part I: Channel and receiver presentation
Author :
Eggen, Trym H. ; Baggeroer, Arthur B. ; Preisig, James C.
Author_Institution :
Simrad AS, Horten, Norway
Abstract :
Scattering functions from several experiments demonstrate that acoustic underwater channels are doubly spread. Receivers used on these channels to date have difficulty with large Doppler spreads. A receiver to perform coherent communication over Doppler spread channels is presented in this first paper of two. The receiver contains a channel tracker and a linear decoder. The tracker operates by means of a modified recursive least squares algorithm which makes use of frequency-domain filters called Doppler lines. The decoder makes use of the channel tracker coefficients in order to perform minimum mean square error decoding. This first paper treats theoretical aspects whereas the second part presents implementation issues and results.
Keywords :
Doppler shift; Wiener filters; acoustic correlation; acoustic receivers; adaptive decoding; adaptive signal processing; filtering theory; least squares approximations; mean square error methods; quadrature phase shift keying; time-varying channels; underwater acoustic communication; Doppler lines; Doppler spread channels; QPSK modulation; Wiener filter; acoustic signal processing; acoustic underwater channels; channel model; channel tracker; coherent communication; correlation; digital communication; doubly spread channels; frequency-domain filters; linear decoder; minimum mean square error decoding; modified recursive least squares algorithm; receiver; scattering functions; Decoding; Diversity reception; Frequency shift keying; Least squares methods; Oceans; Phase shift keying; Signal processing algorithms; Underwater acoustics; Underwater communication; Underwater tracking;
Journal_Title :
Oceanic Engineering, IEEE Journal of
