Column-anchored zeroforcing blind equalization for multiuserwireless FIR channels

摘要

We propose a direct blind zeroforcing approach to cancelnintersymbol interference (ISI) in multiple user finite impulse responsen(FIR) channels. By selectively anchoring columns of the channelnconvolution matrix, we present two column-anchored zeroforcingnequalizers (CAZE), one without output delay and one with a chosen delay.nUnlike many known blind identification algorithms, these equalizers donnot need an accurate estimate of the channel orders. Exploitingnsecond-order statistics (SOS) of the received signals, they can retainnpreselected d columns in the channel convolution matrix (d is the numbernof users) and force the remaining columns to zero. CAZE can effectivelynequalize single-input-multiple-output (SIMO) systems and can reducendynamic multiple-input-multiple-output (MIMO) systems into a memorylessnsignal mixing system for source separation. Simulation results show thatnthe CAZE is not only effective for blind equalization of linearnquadrature amplitude modulation (QAM) systems, but it is also applicablento the nonlinear GMSK modulation in the popular wireless GSM systemsnwhen computational cost severely limits the use of nonlinear methodsnsuch as the Viterbi algorithm