An iterative beamforming scheme based on leakage sum-rate maximization criterion

In this paper, we study an iterative beamforming scheme for downlink multiuser channels. The sum-rate of the system can be maximized by weighted sum-rate maximization method. However, the interference of leakage signal is not considered in this method. We propose a new metric named leakage sum-rate (LSR) to treat leakage interference. Then, the leakage sum-rate maximization is modeled by the power budget constraint of base stations. The optimization problem can be transformed to an equivalent weighted mean-square error minimization (WMMSE) problem and an iterative algorithm is proposed to solve it. In the algorithm, weighted factors, transmit and receive beamformers are updated iteratively. The proposed algorithm outperforms the SLNR maximizing algorithm in terms of the system sum-rate. Compared with the weighted sum-rate maximization scheme, the proposed algorithm can converge to a stationary point more quickly although the system performance is lower. Simulation results illustrate that the algorithm can make a good balance between system performance and complexity.