Non-Stationarities in Extra-Large Scale Massive MIMO

Understand

Massive MIMO, a key technology for increasing area spectral efficiency in cellular systems, was developed assuming moderately sized apertures.

• In this paper, we argue that massive MIMO systems behave differently in large-scale regimes due to spatial non-stationarity.
• In the large-scale regime, with arrays of around fifty wavelengths, the terminals see the whole array but non-stationarities occur because different regions of the array see different propagation paths.
• At even larger dimensions, which we call the extra-large scale regime, terminals see a portion of the array and inside the first type of non-stationarities might occur.