Low-complexity lattice reduction-aided channel inversion methods for large multi-User MIMO systems

Low-complexity precoding algorithms are proposed in this work to reduce the computational complexity and improve the performance of regularized block diagonalization (RBD) based precoding schemes for large multi-user MIMO (MU-MIMO) systems. The proposed algorithms are based on a channel inversion technique, QR decompositions, and lattice reductions to decouple the MU-MIMO channel into equivalent SU-MIMO channels. Simulation results show that the proposed precoding algorithms can achieve almost the same sum-rate performance as RBD precoding, substantial bit error rate (BER) performance gains, and a simplified receiver structure, while requiring a lower complexity.