Leakage based users selection for hybrid beamforming in millimeterwave MIMO
Résumé
Millimeter-Wave (mmWave) channels are characterized as being sparse and Line of Sight (LoS) dominated. Applying hybrid beamforming in mmWave systems guarantees Multi-User (MU) transmission with low hardware requirements. Zero Forcing (ZF) precoding can be utilized at the digital layer of the hybrid beamformer to mitigate the Inter User Interference (IUI). However, due to the sparse nature of the mmWave channels, a ZF precoder may provide limited performance due to the highly correlated MU channel matrix. The aim of this paper is hence to address the interference mitigation problem in the analog domain before handling it at the ZF digital level. Signal to Leakage and Noise Ration (SLNR) based users selection algorithm is introduced for maximizing the Spectral Efficiency (SE) of the system with low complexity requirements.We finally highlight by simulations the potential gains achieved by the introduced interference aware users selection approach.