Non-Stationarities in Extra-Large-Scale Massive MIMO

By E. de Carvalho, Anum Ali, A. Amiri, Marko Angjelichinoski, Robert W. Heath. IEEE wireless communications, 2019

308 citations recorded by the source corpus.

Massive MIMO, a key technology for increasing area spectral efficiency in cellular systems, was developed assuming moderately sized apertures. In this article, 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 50 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. We show that the non-stationarity properties of the massive MIMO channel change several important MIMO design aspects. In simulations, we demonstrate how non-stationarity is a curse when neglected but a blessing when embraced in terms of computational load and multi-user transceiver design.

Subfields: Aerospace Engineering, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/8c468e2460ebe4104ac1efccb13b491e002f4489

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Citations in the corpus

Channel Estimation for Extremely Large-Scale MIMO: Far-Field or Near-Field? (2021, background): “For future 6G communications, extremely large-scale MIMO (XL-MIMO) [3], where the number of antennas can be much larger than that for massive MIMO, can effectively achieve 10-fold increases in spectrum efficiency [4].”
An Overview of Signal Processing Techniques for Terahertz Communications (2020, background): “This results in non-stationarity [117] and variations in the time of arrival, angle of arrival (as well as the angle of departure), and receive amplitudes across the antenna array.”
Prospective Multiple Antenna Technologies for Beyond 5G (2019, background): “Scaling laws should also be investigated for real-world channels, such as with mixed line-of-sight (LoS) and non-LoS propagation, and other non-stationary channels [79], [80].”
Communicating With Extremely Large-Scale Array/Surface: Unified Modeling and Performance Analysis (2021, unknown): “Speciﬁcally, as the array size increases, different regions of the array may observe distinct propagation environment, e.g., different blockers and/or cluster sets, and hence exhibit different levels of received power [15].”
A Tutorial on Extremely Large-Scale MIMO for 6G: Fundamentals, Signal Processing, and Applications (2023, background): “…to be considered in mMIMO The consideration of new EM characteristics such as the spherical wave characteristic [45] and spatial non-stationarity [46], and brand-new near-field based channel models such as the Fourier plane-wave representation based channel models [47] The capture of actual EM…”
6G Wireless Systems: Vision, Requirements, Challenges, Insights, and Opportunities (2020, background): “Several measurement-based studies have demonstrated the above effects quantitatively (see [148]–[150] and [158]).”
Convergent Communication, Sensing and Localization in 6G Systems: An Overview of Technologies, Opportunities and Challenges (2021, background): “However, the channel model becomes non-stationary in space since certain parameters, e.g., path loss and angle of arrival (AoA), can not be assumed to be constant between the antennas [30].”
A Tutorial on Near-Field XL-MIMO Communications Toward 6G (2023, unknown): “The occurrence of BS-side VR can be viewed as two major manifestations [26]: 1) unequal pathloss across the array, and 2) signal blockage stemming from obstacles between the UE and the array.”