A suboptimal equalizer for mimo systems to guarantee maximum diversity and near linear equalization complexity

MIMO transmissions (e.g., V-BLAST) have been widely adopted for high-rate high-performance systems. When the maximum likelihood (ML) or near-ML detector is employed, receive diversity is collected for V-BLAST systems with high complexity. On the other hand, linear equalizers (LEs) require much lower complexity but degrade performance due to the loss of diversity. Lattice reduction (LR) technique has been introduced to restore the diversity of LEs with increased complexity. To further reduce the complexity of LR- aided LEs, in this paper, we propose a suboptimal equalizer which achieves the same diversity order as that collected by ML detector while keeping the complexity close to LEs. Furthermore, the proposed hybrid equalizer also enables trade-off between performance (coding gain) and complexity based on the channel orthogonality deficiency value. Simulation results corroborate our theoretical claims.