Bayesian Learning for Pilot Decontamination in Cell-Free Massive MIMO

Forsch C, Zhao Z, Slock D, Cottatellucci L (2025)

Publication Type: Conference contribution

Publication year: 2025

Publisher: IEEE

City/Town: New York City

Pages Range: 19-25

Conference Proceedings Title: 2025 28th International Workshop on Smart Antennas (WSA)

Event location: Erlangen DE

DOI: 10.1109/WSA65299.2025.11202775

Abstract

Pilot contamination (PC) arises when the pilot sequences assigned to user equipments (UEs) are not mutually orthogonal, eventually due to their reuse. In this work, we propose a novel expectation propagation (EP)-based joint channel estimation and data detection (JCD) algorithm specifically designed to mitigate the effects of PC in the uplink of cell-free massive multiple-input multiple-output (CF-MaMIMO) systems. This modified bilinear-EP algorithm is distributed, scalable, demonstrates strong robustness to PC, and outperforms state-of-the-art Bayesian learning algorithms. Through a comprehensive performance evaluation, we assess the performance of Bayesian learning algorithms for different pilot sequences and observe that the use of non-orthogonal pilots can lead to better performance compared to shared orthogonal sequences. Motivated by this analysis, we introduce a new metric to quantify PC at the UE level. We show that the performance of the considered algorithms degrades monotonically with respect to this metric, providing a valuable theoretical and practical tool for understanding and managing PC via iterative JCD algorithms.

Authors with CRIS profile

Christian Forsch Lehrstuhl für Digitale Übertragung (IDC) Laura Cottatellucci Professur für Digitale Übertragung

Involved external institutions

Institut Eurécom (EURECOM) FR France (FR)

How to cite

APA:

Forsch, C., Zhao, Z., Slock, D., & Cottatellucci, L. (2025). Bayesian Learning for Pilot Decontamination in Cell-Free Massive MIMO. In 2025 28th International Workshop on Smart Antennas (WSA) (pp. 19-25). Erlangen, DE: New York City: IEEE.

MLA:

Forsch, Christian, et al. "Bayesian Learning for Pilot Decontamination in Cell-Free Massive MIMO." Proceedings of the 2025 28th International Workshop on Smart Antennas (WSA), Erlangen New York City: IEEE, 2025. 19-25.

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