Linear Receivers in Non-stationary Massive MIMO Channels with Visibility Regions

TL;DR

This paper analyzes the impact of spatial non-stationarity in massive MIMO channels with visibility regions, deriving SINR expressions for linear receivers and comparing their performance.

Contribution

It introduces a channel model based on visibility regions and provides new SINR expressions and deterministic equivalents for non-stationary massive MIMO channels.

Findings

Visibility regions significantly affect SINR performance.

ZF precoders outperform conjugate beamforming in certain configurations.

Non-stationary channel models provide more accurate performance predictions.

Abstract

In a massive MIMO system with large arrays, the channel becomes spatially non-stationary. We study the impact of spatial non-stationarity characterized by visibility regions (VRs) where the channel energy is significant on a portion of the array. Relying on a channel model based on VRs, we provide expressions of the signal-to-interference-plus-noise ratio (SINR) of conjugate beamforming (CB) and zero-forcing (ZF) precoders. We also provide an approximate deterministic equivalent of the SINR of ZF precoders. We identify favorable and unfavorable multi-user configurations of the VRs and compare the performance of both stationary and non-stationary channels through analysis and numerical simulations.