Blind Channel Equalization and Carrier Phase Tracking with Application to Offset Quadrature Signals

摘要

A joint blind equalizer and carrier phase tracking loop is presented for a non-linearly amplified(NLA) offset quadrature signals(OQS) and more specifically Feher's quadrature phase shift keying(FQPSK) signal transmitted over a multipath frequency selective fading channel. By using an offset samplig scheme to estimate the pahse error, a T_s/2-spaced fractionally spaced equalizer(T_s/2-FSE) based on a widely referenced constant modulus algorithm (CMA) can converge to the minimum mean-squared error(MMSE) and exhibits fast carrier fequency offset tracking. The simulation results confirm that the blind T_s/2-FSE which uses the porposed scheme for FQPSK can effectively reduce intersymbol interference (ISI) and correct carrier phase error.