Nonlinear precoding scheme for the downlink of multiuser MIMO cognitive radio networks

This paper aims to solve the problem that the cognitive base station (CBS) minimizes the BER and maximizes the sum capacity in the condition of the interference constraint for the primary users (PUs). The main contribution of this paper is applying three kinds of THP algorithm in the multiple user multi-input multi-output (MU-MIMO) system to cognitive radio (CR) network by using matrix decomposition. The Computer simulations of these modified algorithm shows that cognitive minimum mean square error block diagonal Tomlinson-Harashima precoding (CR-MMSE-BD-THP) has better performance.