Near-optimal MIMO detection algorithm with low and fixed complexity

In this paper, we propose a near-optimal multiple-input multiple-output (MIMO) detection algorithm with low and fixed complexity, which is based on the fixed-complexity sphere decoder (FSD). By employing the lattice reduction (LR) to the FSD, the computational complexity is reduced considerably while maintaining the near-optimal bit-error-rate (BER) performance. Although the application of LR to the FSD is not straightforward, an efficient solution is proposed in this paper. The numerical results demonstrate that the computational complexity of the proposed algorithm is reduced by about 43.02% and 76.49% for 64-QAM and 256-QAM compared to the optimal FSD while the performance degradation is negligible.