List LRAD based on Semi-Definite Relaxaion for MIMO Systems

We already know that the Maximum Likelihood (ML) detection in multiple-input multiple-output (MIMO) channels has optimal performance. However its complexity is very serious problem to make it in capable of real time implementation. To simplify the complexity of MLD, many linear and nonlinear techniques have been proposed. In this paper, we propose the list Lattice Reduction Aided detector (LRAD) based on semi-definite relaxation(SDR) for MIMO systems. Simulation results in MIMO system, the proposed scheme has 2dB better performance than the LR-MMSE (H) for a BER of 10^-4. Although the complexity of the proposed scheme is slightly higher than conventional LRAD, its performance is closed to MLD in high SNR region.