A Leakage-Based Precoding Scheme for Cognitive Multiuser MIMO Systems

In this paper, we develop linear precoding schemes for cognitive radio (CR) multiuser multiple-input multiple-output (MU-MIMO) downlink systems. A secondary user base station (SBS) with multiple secondary users (SUs) sharing the primary user (PU) spectrum is considered. In the proposed scheme, the block diagonalization (BD) algorithm is adopted to remove the co-channel interference from the SBS to the PU completely, and the matching weighted signal-to-leakage-and-noise ratio (SLNR) maximization algorithm is proposed to mitigate interference between SUs. The proposed scheme does not require a strict restriction on the number of transmit and receive antennas. Simulation results show that the proposed scheme can achieve high sum rate throughput with affordable complexity.