Linear precoding design for cognitive multiuser MIMO systems using a leakage-based approach

Abstract

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 diagonalisation (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) maximisation algorithm is proposed to mitigate interference between SUs. We also discuss the cases where the SBS has only partial channel information and the channel estimation with errors, respectively. 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.