MU-MIMO Downlink Sum Rate Analysis Based on SLNR and Optimum Code Vector Design for Millimeter Wave Communications

Abstract

Multi User-Multiple Input Multiple Output (MU-MIMO) wireless communication systems, can provide substantial downlink throughput in millimetre wave (mmW) communication by allowing multiple users to communicate on the same frequency and time slots. However, the design of an optimum beam-vector for each user to minimise the interference from other users is challenging. In this work, based on the concept of signal to leakage plus noise ratio (SLNR), we discuss the statistical eigenmode (SE) and zero-forcing (ZF) in Ricean fading channels regarding the ergodic sum-rate capacity. Moreover, also we show the effects of the number of antenna elements, on the achievable rate obtained by dirty paper coding method (DPC). Furthermore, we proposed a new solution method to find an optimum beam-vector, which maximise the SLNR and lead to increase the system capacity directly. The proposed method is based on power approximation, to find the most dominant eigenvector iteratively, to minimise the co-channel interference (CCI). Compared the proposed method with the singular value decomposition (SVD) solution, our proposed method achieved higher performance than SVD regarding achievable sum rate. Indeed, the maximum achieved average system capacity, for our proposed method is almost two times of the capacity achieved by SVD.