Adaptive equalization of nonlinear digital satellite channels using a frequency-domain Volterra filter

The objective of this paper is to present a new structure for an adaptive nonlinear equalizer for digital transmission over a nonlinear satellite channel with PSK modulation. The adaptive nonlinear equalizer is based on a discrete frequency-domain, third-order Volterra filter with the multidimensional overlap-save filtering technique, and on the block least mean square (BLMS) algorithm for updating the filter coefficients. Since the proposed equalizer performs fast convolution by blocks, in decision-directed mode, it provides potentially larger savings in computational complexity compared to the conventional time-domain Volterra equalizers. The feasibility and practicality of the proposed equalizer structure is demonstrated by utilizing it to equalize a nonlinear satellite channel.