PSO-based Searching Precoding for MU-MIMO System

This paper deals with the design of optimal linear precoder for multi-user multiple-input multiple-output (MU-MIMO) system. The singular value decomposition (SVD) precoder under the ideal channel condition is introduced. However, in the circumstance with general conditions, due to co-channel interference (CCI), the system capacity degradation of MU-MIMO system is influenced by the efficacy decreasing of the precoder. Therefore, a linear precoder based on particle swarm optimization (PSO) algorithm to conduct optimal searching of the precoding matrix for the individual users is proposed in this paper. With the objective function for maximizing output signal to interference plus noise ratio, the proposed PSO-searching based (PSB) precoder can suppress CCI and improve system capacity effectively. For the purpose to enhance the accuracy and speed of the optimal solution searching, the improved PSO-searching based (IPSB) precoder has been provided, which depends on the marginal effect of capability of the global exploration. Several computer simulations are provided for illustration and comparison.