Normalized Volume of Hyperball in Complex Grassmann Manifold and Its Application in Large-Scale MU-MIMO Communication Systems

摘要

This paper provides a solution to a critical issue in large-scale Multi-UserMultiple-Input Multiple-Output (MU-MIMO) communication systems: how to estimatethe Signal-to-Interference-plus-Noise-Ratios (SINRs) and their expectations inMU-MIMO mode at the Base Station (BS) side when only the Channel QualityInformation (CQI) in Single-User MIMO (SU-MIMO) mode and non-ideal ChannelState Information (CSI) are known? A solution to this problem would be verybeneficial for the BS to predict the capacity of MU-MIMO and choose the propermodulation and channel coding for MU-MIMO. To that end, this paper derives anormalized volume formula of a hyperball based on the probability densityfunction of the canonical angle between any two points in a complex Grassmannmanifold, and shows that this formula provides a solution to the aforementionedissue. It enables the capability of a BS to predict the capacity loss due tonon-ideal CSI, group users in MU-MIMO mode, choose the proper modulation andchannel coding, and adaptively switch between SU-MIMO and MU-MIMO modes, aswell as between Conjugate Beamforming (CB) and Zero-Forcing (ZF) precoding.Numerical results are provided to verify the validity and accuracy of thesolution.