Utilizing a Parametric Channel Model to Improve Turbo Equalization for Underwater Communications
نویسنده
چکیده
A model based method for channel estimation and synchronization in a sevearly doppler spread channel is presented. The model parameters are delay, amplitude and doppler (compression/expansion). The parametrs are succesively determined for a number of signal arrivals starting with the strongest and down to the level that is considered significant for the communication. The residual is taken care of by an ordinary non parametric channel estimation. Another novelty is the signal model that is presented. In soft recursive estimation of a message the channel is overestimated when the knowledge of the received symbols is small. To overcome this the phases or amplitudes are constrained to the values that are possible with respect to the modulation format. The results show considerably better convergence in channels with severe doppler shift and varying channel coefficients. The abstract goes here.
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