Low complexity QRM-MLD algorithm for MIMO systems with 256 QAM modulations

An improved detection scheme is proposed for the MIMO-OFDM system with 256QAM modulation. Unlike the conventional QRM-MLD approaches, the proposed scheme reduces the expanded nodes of every parent nodes in each layer using the hierarchical structure of 256 QAM. Simulation results show the complexity of the proposed method is about one-sixth that of QRM-MLD significantly for the same performance. Moreover, for similar complexity, the proposed method has the 2dB gain compared with QRM-MLD method at the BER of 10−4.