Reduced-complexity LLL algorithm for lattice-reduction-aided MIMO detection

In this paper, we propose a low-complexity constant-throughput LLL algorithm for lattice-reduction-aided (LRA) multi-input multi-output (MIMO) detection. The traditional LLL algorithm for the lattice reduction has a drawback of varying throughput due to the variable iteration loops for the size-reduction and LLL-reduction checks. To address this problem, we propose a constant-throughput LLL (CT-LLL) algorithm that is well suited for real-time implementation. We further propose some techniques to reduce the redundant operations in the CT-LLL algorithm so that the computational complexity can be reduced. Simulation and analysis results show that the proposed low-complexity CT-LLL algorithm reduces the complexity of the CT-LLL algorithm for 4×4 and 8×8 MIMO systems to 80% and 72.94%, respectively, with negligible performance degradation.