Complex structured lattice reduction aided linear detection with lower complexity for STBC two-user uplink MIMO systems

In this paper, we propose a simple but effective lattice reduction (LR) scheme for an uplink with two antennas at the base station and two-users, each employing the Alamouti space-time block coding (STBC). By exploiting the inherent STBC structure of transmitted symbols from users, the proposed scheme computes the LLL-reduced channel matrix with low complexity. Simulation results reveal that the proposed scheme can achieve the same performance as a conventional lattice reduction schemes while saving about 70% computational complexity in terms of floating-point operations (flops).