Hybrid higher-order cepstrum and functional link network-based blind equaliser (HOCFLN)

Abstract

A new hybrid higher-order cepstrum (HOC) and functional link network (FLN)-based blind equaliser (HOCFLN) is presented. The system initially uses the complex cepstrum of the 1-D slice of the fourth-order cumulants of the unknown received signal to partially estimate the equaliser coefficients, then it switches to an FLN adaptive equaliser operating in the decision directed mode (DDM) to further improve the mean-squared error (MSE) convergence. In this system two nonlinearities are used; one on the input data where the HOC is used and the other one in the FLN equaliser filter. It is shown that in the new HOCFLN system multiple nonlinearities give significant performance improvement with less computational complexity, particularly in severe channel distortion compared to the conventional equalisation algorithms. This method can accommodate both nonminimum phase MA and ARMA channels. Performance results for channels exhibiting abrupt characteristic changes are also shown.