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.
Bibliographical noteFunding Information:
Manuscript received July 30, 2008; accepted January 15, 2009. First published February 24, 2009; current version published May 15, 2009. The associate editor coordinating the review of this manuscript and approving it for publication was Dr. Aleksandar Dogandzic. This work was supported in part by the EU FP6 COOPCOM project (#FP6-033533) and in part by the PENED #03ED838 research project, co-financed by national and E.C. funds. This work was presented in part at the IEEE Vehicular Technology Conference, Baltimore, MD, October 2007.
- Adaptive equalizers
- Conjugate gradient methods
- Decision feedback equalizers
- Galerkin method
- MIMO systems