Blind MIMO equalization using subband affine projection algorithm with IIR filterbank

If the data are prewhitened, then gradient adaptive algorithms which are simpler than higher order statistics algorithm, can be used in blind equalization. In this paper, we propose a subband affine projection algorithm with improved convergence performance and reduced computational complexity for multiple-input multiple-output equalization in the blind environments. All of the adaptive filters in subband affine projection equalization are decomposed to polyphase components, and the coefficients of the decomposed adaptive subfilters are updated by defining the multiple cost functions. An infinite impulse response filterbank is designed for the data prewhitening. Prewhitening data through subband filtering can speed up the convergence rate without additional computation. Simulation results are presented showing the proposed algorithm´s convergence rate and constellation equalization performance.