Adaptive Conjugate Gradient DFEs for Wideband MIMO Systems
New adaptive equalization algorithms for wireless systems operating over wideband multiple-input multiple-output (MIMO) channels are proposed. The problem of MIMO decision feedback equalizer (DFE) design is formulated as a set of linear equations with multiple right-hand sides (RHSs) evolving in time. By applying an adaptive modified conjugate gradient algorithm, we derive an equalizer with identical convergence, improved tracking capabilities, but higher computational load as compared to the Recursive Least Squares (RLS) algorithm. To reduce its complexity, two updating strategies of the equalizer filters based on Galerkin projections are employed.