Adaptively Varying Modulus Blind Equalization Algorithm Using Fractionally-Spaced Equalizer

A new blind equalization scheme for QAM systems is proposed, which is referred to adaptively varying modulus algorithm based on SCA (A VSCA). The A VSCA changes the SCA from single modulus to multi-modulus for the characteristics of the QAM systems and then adapts the zero- error contours adaptively according to the decision of the equalizer output. Simulation using a fractionally-spaced equalizer for a typical voice-band communication channel and a practical microwave channel is evaluated to compare the proposed algorithm with the CMA, GSA and SCA. Theoretical analysis and simulation results demonstrate that A VSCA improves equalization performance by increasing the convergence speed and decreasing the residual inter-symbol interference.