[en] We consider a two-way half-duplex decode-and-forward (DF) relaying system with multiple pairs of single-antenna users assisted by a cell-free (CF) massive multiple-input multiple-output (mMIMO) architecture with multiple-antenna access points (APs). Under the practical constraint of imperfect channel state information (CSI), we derive the achievable sum spectral efficiency (SE) for a finite number of APs with maximum ratio (MR) linear processing for both reception and transmission in closed-form. Notably, the proposed CF mMIMO relaying architecture, exploiting the spatial diversity, and providing better coverage, outperforms the conventional collocated mMIMO deployment. Moreover, we shed light on the power-scaling laws maintaining a specific SE as the number of APs grows. A thorough examination of the interplay between the transmit powers per pilot symbol and user/APs takes place, and useful conclusions are extracted. Finally, differently to the common approach for power control in CF mMIMO systems, we design a power allocation scheme maximizing the sum SE.
Disciplines :
Computer science
Author, co-author :
PAPAZAFEIROPOULOS, ANASTASIOS K.
KOURTESSIS, PANDELIS
Chatzinotas, Symeon ; University of Luxembourg > Interdisciplinary Centre for Security, Reliability and Trust (SNT) > SigCom
SENIOR, JOHN M.
External co-authors :
yes
Language :
English
Title :
Multipair Two-Way DF Relaying with Cell-Free Massive MIMO
Publication date :
2021
Journal title :
IEEE Open Journal of the Communications Society
ISSN :
2644-125X
Publisher :
Institute of Electrical and Electronics Engineers (IEEE), New York, United States - New York