A zero-forcing linear precoder for downlink multi-user LoS MIMO channels

Abstract

In this paper we introduce an algorithm to design a zero-forcing linear precoder for downlink multi-user Line-of-Sight (LoS) MIMO systems. We observe that the existence of LoS component, changes the restrictions of conventional SVD-BD approach on channel dimensions and correlation of users. In addition, we find a new criterion that relates the received signal to noise ratio and optimal form of pure LoS channel matrix. We perceive that this algorithm improves performance nearly 1.5 dB in compare to the SVD-BD method for Rayleigh channels in the case of two users.