Reduced search space scheme for detection of spatial division multiplexing

We introduce a suboptimal detection scheme for spatial division multiplexing (SDM) using multiple transmit and receive antennas. As a conventional detection method, zero-forcing (ZF) detection shows inferior performance to the optimal maximum likelihood (ML) scheme because it does not exploit the pattern of the weighted noise characterized by singular values and vectors of a corresponding channel matrix. Therefore, the proposed scheme finds a tentative solution with reduced candidates near the ZF filtering output. The search space is extend in the direction of minimizing the ML cost function and we find the final solution to overcome the ZF performance loss. The proposed detector has low complexity while keeping the performance comparable to the ML and other detection methods.