Cell-Free Massive MIMO with Large-Scale Fading Decoding and Dynamic Cooperation Clustering

Konferenz: WSA 2021 - 25th International ITG Workshop on Smart Antennas
10.11.2021 - 12.11.2021 in French Riviera, France

Tagungsband: ITG-Fb. 300: WSA 2021

Seiten: 6Sprache: EnglischTyp: PDF

Demir, Oezlem Tugfe (Department of Computer Science, KTH Royal Institute of Technology, Sweden)
Bjoernson, Emil (Department of Computer Science, KTH Royal Institute of Technology, Sweden & Department of Electrical Engineering (ISY), Linköping University, Sweden)
Sanguinetti, Luca (Dipartimento di Ingegneria dell’Informazione, University of Pisa, Italy)

This paper considers the uplink of user-centric cellfree massive MIMO (multiple-input multiple-output) systems. We utilize the user-centric dynamic cooperation clustering (DCC) framework and derive the achievable spectral efficiency with two-layer decoding that is divided between the access points and the central processing unit (CPU). This decoding method is also known as large-scale fading decoding (LSFD). The fronthaul signaling load is analyzed and a nearly optimal second-layer decoding scheme at the CPU is proposed to reduce the fronthaul requirements compared to the optimal scheme.We also revisit the joint optimization of LSFD weights and uplink power control and show that the corresponding max-min fair optimization problem can be solved optimally via an efficient fixed-point algorithm. We provide simulations that bring new insights into the cell-free massive MIMO implementation.