SPS Webinar: Bilinear Expectation Propagation for Distributed Semi-Blind Joint Channel Estimation and Data Detection in Cell-Free Massive MIMO
Date: 07-November-2025
Time: 08:00 AM ET (New York Time)
Presenters: Mr. Alexander Karataev, Mr. Christian Forsch & Dr. Laura Cottatellucci
Based on the IEEE Xplore® article under the same title
Published: IEEE Open Journal of Signal Processing, January 2024.
Download article: Original article is open access and publicly available for download.
ARTICLE LINK
Abstract
We consider a cell-free massive multiple-input multiple-output (CF-MaMIMO) communication system in the uplink, which is particularly prone to the detrimental effects of pilot contamination (PC), a phenomenon that occurs when pilot sequences assigned to user equipments (UEs) are not mutually orthogonal, eventually due to their reuse. To combat PC, the presenters propose a novel algorithm for blind or semi-blind joint channel estimation and data detection (JCD). They formulate the problem in the framework of bilinear inference and develop a solution based on the expectation propagation (EP) method for both channel estimation and data detection. Specifically, they introduce a new approximation of the joint a posteriori distribution of the channel and transmitted data whose representation as a factor graph enables the application of EP through message-passing. This allows for local low-complexity computations at the nodes and effectively capture the interplay between channel and data. The resulting algorithm, called bilinear-EP JCD, supports distributed implementation across access points (APs) and the central processing unit (CPU) and operates with polynomial complexity. Their simulation results show that their approach outperforms existing EP-based, state-of-the-art polynomial-time algorithms and effectively reduce pilot contamination.
Biography
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Alexander Karataev is specializing in signal processing and communications, with a focus on distributed inference, channel estimation, and efficient computation in wireless networks.
His recent work includes the development of novel algorithms for joint channel estimation and data detection in cell-free massive MIMO systems. His research interests span statistical signal processing, distributed communication systems, and algorithmic approaches for scalable computation in networked systems.
Christian Forsch (S’22) received the B.Sc. and M.Sc. degrees in electrical engineering from the Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany, in 2019 and 2021, respectively, where he is currently working toward the Ph.D. degree. His research interests include Bayesian learning, cell-free massive MIMO communication systems, and terahertz communications.
Laura Cottatellucci (S’01–M’06) received the M.Sc. degree in electrical engineering from La Sapienza University of Rome, Italy, the Ph.D. degree from the Technical University of Vienna, Austria, in 2006, and the Habilitation degree from the University of Nice–Sophia Antipolis, France.
She is currently a Professor at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Germany, since 2017 and since September 2021, she has also held the position of Adjunct Professor at EURECOM, France. Earlier in her career, she worked for five years (1995–2000) at Telecom Italia, focusing on the design of telecommunications networks, and subsequently served as a Senior Researcher at Forschungszentrum Telekommunikation Wien, Austria (2000–2005). She was a Research Fellow at INRIA, France, from October to December 2005, and at the University of South Australia in 2006. From December 2006 to November 2017, she was an Assistant Professor at EURECOM, where she also served as an Adjunct Professor from 2018 to 2019. Her research interests include communication and information theory, and signal processing for wireless communications, satellite systems, and complex networks.
Dr. Cottatellucci was an elected member of the IEEE Technical Committee on Signal Processing for Communications and Networking (2017–2022), and served as an Associate Editor for both the IEEE Transactions on Communications (2015–2020) and the IEEE Transactions on Signal Processing (2016–2020). Since September 2022, she has been a Senior Member of the Editorial Board of the IEEE Signal Processing Magazine.
