Robust and fair multiuser downlink precoding scheme based on weighted generating interference

In this paper a novel downlink precoding algorithm is proposed and assessed in the presence of imperfect channel state information. In this scheme, we focus on protecting the cell-edge user´s performance to solve the fairness issue in conventional downlink precoder which is based on the criteria of maximizing the signal to leakage interference plus noise ratio (SLNR). Weighted factors are introduced into the expression of transmitter´s SLNR to fairly distribute the generating interference among co-channel users. Additionally, through introducing the channel ambiguity into the design of downlink precoder, a robust precoding vector is computed according to the newly defined signal to weighted generating interference plus noise ratio. Simulation results demonstrate the superiority of proposed scheme over conventional schemes in terms of fairness among all users and robustness against the channel uncertainty.