Low-Complexity MIMO Detection Based on Post-Equalization Subspace Search

Two low-complexity effective detection schemes for multiple-input-multiple-output (MIMO) systems based on post-equalization subspace search are proposed in this paper. With the initial solution given by the linear detector, calibrated constellation search is conducted in symbol subspace and eigenspace associated with the largest estimation errors in linear detection to identify improved solutions. Complexity analysis is performed to understand the cost of the proposed add-on procedures. Simulation results demonstrate that the proposed schemes yield noticeable performance gains over linear detectors at moderate additional computational cost.