题目：Fundamentals of Cell-Free Massive MIMO: From Ground to Space
摘要：After five generations of cellular network technology, we are approaching the end of its evolution due to unavoidable intercell interference and geometric variations in signal strength. Suppose all the antennas serving mobile terminals are distributed across the coverage area rather than co-located in arrays at a few elevated locations, as in cellular networks. In such a post-cellular network, mobile terminals are surrounded by antennas rather than having a few base stations surrounded by terminals. If each terminal is served by joint transmission and reception from multiple neighboring base stations, we have a “User-Centric Cell-Free Massive MIMO system”.
In this talk, we will first go through the fundamentals and motivation behind the cell-free technology. This includes the basic models and algorithms for channel estimation and data transmission in ground networks, considering both uplink and downlink. Tradeoffs between centralized, sequential, and distributed signal processing are covered, and the radio stripes topology. We then explore whether some form of cell-free networks could be used in emerging low-Earth-orbit (LEO) satellite networks. Would it be feasible for multiple satellites to jointly transmit to users on the ground, or are such networks poised to be cellular?
时间：2026年7月10日，10:00-11:00
地点：紫金山实验室二楼报告厅2
个人简介：
Emil Björnson is a Professor of Wireless Communication at the KTH Royal Institute of Technology, Stockholm, Sweden. He is an IEEE Fellow, Digital Futures Fellow, Wallenberg Academy Fellow, and Clarivate Highly Cited Researcher. He has a podcast and YouTube channel called Wireless Future. His research focuses on multi-antenna communications and radio resource management, using methods from communication theory, signal processing, and machine learning. He has authored four textbooks and published 70 simulation code repositories.
He has received the 2018 and 2022 IEEE Marconi Prize Paper Awards in Wireless Communications, the 2019 EURASIP Early Career Award, the 2019 IEEE Communications Society Fred W. Ellersick Prize, the 2019 IEEE Signal Processing Magazine Best Column Award, the 2020 Pierre-Simon Laplace Early Career Technical Achievement Award, the 2020 CTTC Early Achievement Award, the 2021 IEEE ComSoc RCC Early Achievement Award, the 2023 IEEE ComSoc Outstanding Paper Award, and the 2024 IEEE Stephen O. Rice Prize.
