Michail Matthaiou

TL;DR: A comprehensive survey of mmWave communications for future mobile networks (5G and beyond) is presented, including an overview of the solution for multiple access and backhauling, followed by the analysis of coverage and connectivity.

TL;DR: It is found that regardless of the Ricean K-factor, in the case of perfect CSI, the approximations converge to the same constant value as the exact results, as the number of base station antennas grows large, while the transmit power of each user can be scaled down proportionally to 1/M.

TL;DR: This work considers the cell-free massive multiple-input multiple-output (MIMO) downlink, where a very large number of distributed multiple-antenna access points (APs) serve many single-ant antenna users in the same time-frequency resource, and derives a closed-form expression for the spectral efficiency taking into account the effects of channel estimation errors and power control.

TL;DR: In this article, the authors survey three new multiple antenna technologies that can play key roles in beyond 5G networks: cell-free massive MIMO, beamspace massive mIMO and intelligent reflecting surfaces.

TL;DR: In this article, the authors considered a multi-user decode-and-forward relay channel, where multiple sources transmit simultaneously their signals to multiple destinations with the help of a full-duplex relay station and derived an exact achievable rate expression in closed-form for MRC/MRT processing and an analytical approximation of the achievable rate for ZF processing.