Near-Field Modeling and Performance Analysis for Multi-User Extremely Large-Scale MIMO Communication

This letter studies the near-field modeling and performance analysis for multi-user extremely large-scale multiple-input multiple-output (XL-MIMO) communication. With the spherical wavefront phase modeling, and by taking into account the variations of signal amplitude and projected aperture across array elements, the performance of the three typical beamforming schemes are investigated, namely the maximal-ratio combining (MRC), zero-forcing (ZF), and minimum mean-square error (MMSE) beamforming. Compared to existing uniform plane wave (UPW) model where inter-user interference (IUI) can only be suppressed in angular domain, XL-MIMO enables a new degree-of-freedom (DoF) for IUI suppression by distance separation, even for users along the same direction. Simulation results are provided to validate the modeling and performance analysis of multi-user XL-MIMO communications.