【GIR Open Seminar】 Dr. Antti Tölli / University of Oulu (Finland)

Date	2023.11.17 (15：00 - 17：00)
Venue	Lecture Room L0831, 3F, Building 8, Koganei Campus, TUAT Zoom Meeting ID:825 5899 4133 Passcode:824628
Speaker	Dr. Antti Tölli
Affiliation	University of Oulu (Finland)
Title	"Distributed Unicast and Multicast Precoding Design via Over-the-Air Signaling for Cell-Free Massive MIMO" ＜Abstract＞ Most works on cell-free massive multiple-input multiple-output (MIMO) consider non-cooperative precoding strategies at the base stations (BSs) to avoid extensive channel state information (CSI) exchange via backhaul signaling. However, considerable performance gains can be achieved by allowing for (limited) coordination among the BSs. This talk introduces a fully distributed framework for cooperative precoding design in cell-free massive MIMO (and, more generally, in joint transmission coordinated multi-point) systems that entirely eliminates the need for backhaul signaling for CSI exchange. The proposed novel over-the-air (OTA) signaling mechanism allows each BS to obtain the same cross-term information that is traditionally exchanged among the BSs via backhaul signaling. To design the joint network-wide unicast and multi-group multicast precoders at the BSs and the combiners at the user equipment (UE) in a fully distributed fashion, we adopt an iterative bi-directional training scheme with UE-specific and/or group-specific precoded uplink and downlink pilots. The proposed distributed precoding designs enjoy desirable flexibility and scalability properties, as the amount of OTA signaling does not scale with the number of BSs or UEs. Numerical results show fast convergence and remarkable performance gains compared with non-cooperative precoding designs. The proposed schemes can also outperform centralized precoding designs under realistic CSI acquisition.
Language	English
Intended for	Everyone is welcome to join.
Co-Organized by	Institute of Global Innovation “Life Science” Umebayashi Team Excellent Leader Development for Super Smart Society by New Industry Creation and Diversity
Contact	Institute of Global Innovation Research, Institute of Engineering Prof. Kenta Umebayashi e-mail: ume_k (at) cc.tuat.ac.jp
Remarks	-Bio- Antti Tölli (M’08, SM’14) is a Professor at the Centre for Wireless Communications (CWC), University of Oulu. He received his Dr.Sc. (Tech.) degree in electrical engineering from the University of Oulu, Finland, in 2008. From 1998 to 2003, he worked at Nokia Networks as a Research Engineer and Project Manager in both Finland and Spain. In May 2014, he was granted a five-year (2014-2019) Academy Research Fellow post by the Academy of Finland. During the academic year 2015-2016, he visited EURECOM in Sophia Antipolis, France, while from August 2018 to June 2019, he visited the University of California, Santa Barbara, USA. He has authored numerous papers in peer-reviewed international journals and conferences and holds several patents in the area of signal processing and wireless communications. His research interests include radio resource management and transceiver design for broadband wireless communications, with a special emphasis on distributed interference management in heterogeneous wireless networks. From 2017 to 2021, he served as an Associate Editor for the IEEE Transactions on Signal Processing.

Event

【GIR Open Seminar】 Dr. Antti Tölli / University of Oulu (Finland)