A new blind equalization scheme for QAM systems based on fractionally-spaced equalizer

A new blind equalization scheme is proposed based on fractionally-spaced equalizer, which referred to concurrent modified square contour algorithm (MSCA) and a novel soft decision-directed (SDD) adaptation. This proposed blind equalization scheme (MSCA+SDD) may be viewed as operating a MSCA fractionally-spaced equalizer which provides good steady-state equalization performance and global convergence and a SDD fractionally-spaced equalizer which helps to accelerate convergence and reduce inter-symbol interference concurrently. Simulation using a fractionally-spaced equalizer for a practical microwave channel is evaluated to compare the proposed algorithm with the MSCA and SCA. Theoretical analysis and simulation results demonstrate that MSCA+SDD using fractionally-spaced equalizer improves equalization performance by increasing the convergence speed and decreasing the residual inter-symbol interference.