Abstract
With the increment in users' data demand and the emergence of applications with stringent Quality of Service requirements, important improvements in cellular network architecture need to be made. In this paper we explore the symbiosis of three key communication technologies in 5G: Device-to-Device communications, 60 GHz unlicensed band transmissions and adaptive beamforming techniques. It provides notable energy saving, improvement in the system spectral efficiency, high achievable data rate and strong interference reduction. Despite these benefits, there are some issues to be analyzed: a limited communication range due to the high path loss, and the interferences among D2D communications, especially if users' density is high. To manage these problems, on the basis of a mmWave network architecture for high UE density indoor environments, we propose a new centralized control for radio access and an efficient multi-criteria scheduling algorithm using greedy graph vertex-coloring techniques. We aim to enhance transmission efficiency, exploiting concurrent transmissions, maximize throughput and minimize end-to-end delay, while taking into account to keep the computational load low.