Optimal sequence detection based on oversampling for bandlimited nonlinear channels

Based on a polynomial representation of a memoryless bandpass nonlinearity, a new realization of an optimal receiver is proposed to perform maximum likelihood detection of data sequences transmitted over nonlinear, possibly time-dispersive, channels. The receiver employs oversampling of the observed signal to compute proper branch metrics for a Viterbi processor. Error performance is compared to that of an optimal receiver for the linear channel obtained by ideal analog predistortion of the nonlinear device under a peak-power constraint. In the presence of nonlinear distortion, a significant improvement in the symbol error rate is shown to be achievable by optimal detection with respect to ideal predistortion. The numerical results are based on both analytic and simulation methods.