Parameter Estimation of DSSS Signals with Line Enhancement

A new adaptive estimator for direct sequence spread spectrum (DSSS) signals using fourth-order cumulant based adaptive method is considered. The general higher-order statistics may not be easily applied in signal processing with too complex computation. Based on the fourth-order cumulant with 1-D slices and adaptive filters, an efficient algorithm is proposed to solve the problem and extended for non-stationary stochastic processes. In order to achieve accurate parameter estimation of direct sequence spread spectrum (DSSS) signals, the first step uses the modified fourth-order cumulant to reduce the computing complexity. While the second step employs an adaptive recursive system to estimate the power spectrum in the frequency domain. For the case of intercepted signals without large enough data samples, the estimator provides good performance in parameter estimation and white Gaussian noise suppression. Computer simulations are included to corroborate the theoretical development with different signal-to-noise ratio conditions and recursive coefficients.